Control strategy setting for electrical stimulation therapy

Abstract

The present disclosure relates to devices, systems, and techniques for controlling electrical stimulation. In some examples, a system includes a user interface and processing circuitry. The processing circuitry is configured to: output, for display by the user interface, a message requesting a patient to perform a set of actions; receive, from the user interface, user input indicative of a patient response associated with the set of actions; and based on the user input, determine one or more adjustments to a control policy that controls electrical stimulation delivered by a medical device based on a plurality of evoked compound action potentials (ECAPs) sensed by the medical device.

Description

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 037,361, filed June 10, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates generally to electrical stimulation therapy, and more specifically to the control of electrical stimulation therapy. Background Technology

[0003] Medical devices can be external or implanted and can be used to deliver electrical stimulation therapy to patients via various tissue sites to treat a variety of symptoms or conditions, such as chronic pain, tremor, Parkinson's disease, epilepsy, urinary and fecal incontinence, sexual dysfunction, obesity, or gastroparesis. Medical devices can deliver electrical stimulation therapy via one or more leads comprising electrodes positioned near target locations associated with the patient's brain, spinal cord, pelvic nerves, peripheral nerves, or gastrointestinal tract. Stimulation near the spinal cord, sacral nerves, brain, and peripheral nerves is commonly referred to as spinal cord stimulation (SCS), sacral nerve modulation (SNM), deep brain stimulation (DBS), and peripheral nerve stimulation (PNS), respectively.

[0004] Evoked compound action potentials (ECAPs) are synchronous firings of a group of neurons in response to the application of a stimulus (in some cases, including electrical stimulation from a medical device). ECAPs can be detected as separate events from the stimulus itself, and they can reveal the characteristics of the stimulus's effect on nerve fibers. Electrical stimulation can be delivered to the patient by a medical device as a series of electrical pulses, and the parameters of these pulses can include frequency, amplitude, pulse width, and pulse shape. The parameters of the electrical pulses can be altered in response to sensory input, such as ECAPs sensed in response to a series of electrical pulses. Such alterations may affect the patient's perception of the electrical pulses, or render them imperceptible. Summary of the Invention

[0005] In general, this disclosure relates to devices, systems, and techniques for controlling electrical stimulation therapy. For example, a medical device may control the level of electrical stimulation based on sensing multiple evoked compound action potentials (ECAPs). In some cases, the medical device may reduce the intensity of the stimulation pulse in response to the characteristics of a detected ECAP signal exceeding a threshold ECAP value, and subsequently increase the intensity of the stimulation pulse after the characteristics of the ECAP signal later fall back below the threshold ECAP value. It may be beneficial to modify the control strategy defining the electrical stimulation to account for the movement of electrodes coupled to the medical device (e.g., one or both of short-term and long-term migrations). More specifically, the techniques of this disclosure may allow processing circuitry to execute algorithms for modifying (e.g., automatically modifying or recommending user modification) the control strategy, which determines how the medical device changes the parameter values ​​defining the electrical stimulation.

[0006] Control strategies can be established at the start of treatment for a patient, changed periodically over time, or changed in response to triggering events. Control strategies can reduce the likelihood that stimuli will cause the patient to experience discomfort (e.g., “transient overstimulation”) and reduce the likelihood that stimuli will cause the patient to experience reduced treatment benefits. The parameters defining the control strategy may also need to be established first and then adjusted over time to maintain effective treatment benefits and reduce the likelihood of undesirable stimuli. The medical device or an external device associated with the medical device can execute an algorithm that elicits a response from the user and determines adjustments to the parameters defining the control strategy based on the user's response.

[0007] Additionally, one or more techniques disclosed herein include receiving and analyzing ECAP data corresponding to events indicated by a patient, wherein the ECAP data may be a factor in determining recommended changes to a control strategy. For example, a medical device may capture ECAP data corresponding to a time period in which a patient responds to a received indication that an event has occurred, the time period including the occurrence of the event. The medical device may output the ECAP data in some format (e.g., a histogram) for later analysis. The device may use the captured ECAP data to recommend one or more changes to a control strategy, or to determine whether to prompt the patient for information useful for making one or more changes to the control strategy.

[0008] In some examples, a system includes a user interface and processing circuitry. The processing circuitry is configured to: output a message requesting a patient to perform a set of actions for display on the user interface; receive user input from the user interface indicating a patient response associated with the set of actions; and, based on the user input, determine one or more adjustments to a control strategy, the control strategy controlling electrical stimulation delivered by the medical device based on at least one evoked compound action potential (ECAP) sensed by the medical device.

[0009] In some examples, one method includes: outputting a message from processing circuitry requesting a patient to perform a set of actions for display by the user interface; receiving user input from the user interface by the processing circuitry indicative of a patient response associated with the set of actions; and determining, based on the user input, one or more adjustments to a control strategy, the control strategy controlling electrical stimulation delivered by the medical device based on at least one evoked compound action potential (ECAP) sensed by the medical device.

[0010] In some examples, a computer-readable medium includes instructions that, when executed by a processor, cause the processor to: output a message requesting a patient to perform a set of actions for display by the user interface; receive user input from the user interface indicating a patient response associated with the set of actions; and, based on the user input, determine one or more adjustments to a control strategy that controls electrical stimulation delivered by the medical device based on at least one evoked compound action potential (ECAP) sensed by the medical device.

[0011] In some examples, a medical device includes: a stimulation generating circuit configured to deliver electrical stimulation to a patient, wherein the electrical stimulation treatment includes a plurality of stimulation pulses; a sensing circuit configured to sense one or more evoked compound action potentials (ECAPs), wherein the sensing circuit is configured to sense each of the one or more ECAPs induced by a corresponding stimulation pulse among the plurality of stimulation pulses; and a processing circuit configured to store a histogram dataset corresponding to a set of ECAPs among the plurality of ECAPs, the set of ECAPs being sensed by the sensing circuit within a time window.

[0012] In some examples, a method includes: delivering electrical stimulation to a patient by a stimulation generation circuit, wherein the electrical stimulation treatment comprises a plurality of stimulation pulses; sensing one or more evoked compound action potentials (ECAPs) by a sensing circuit, wherein the sensing circuit is configured to sense each of the one or more ECAPs evoked by a corresponding stimulation pulse among the plurality of stimulation pulses; and storing by a processing circuit a histogram dataset corresponding to a set of ECAPs among the plurality of ECAPs, the set of ECAPs being sensed by the sensing circuit within a time window.

[0013] In some examples, a computer-readable medium includes instructions that, when executed by a processor, cause the processor to: deliver electrical stimulation to a patient, wherein the electrical stimulation treatment includes a plurality of stimulation pulses; sense one or more evoked compound action potentials (ECAPs), wherein the sensing circuitry is configured to sense each of the one or more ECAPs evoked by a corresponding stimulation pulse from the plurality of stimulation pulses; and store a histogram dataset corresponding to a set of ECAPs from the plurality of ECAPs, the set of ECAPs being sensed by the sensing circuitry within a time window.

[0014] This summary is intended to provide an overview of the subject matter described in this disclosure. It is not intended to provide an exclusive or exhaustive explanation of the systems, apparatus, and methods described in detail in the following drawings and specification. Further details of one or more examples of this disclosure are set forth in the following drawings and specification. Other features, objects, and advantages will become apparent from this specification and drawings, and from the claims. Attached Figure Description

[0015] Figure 1 The present disclosure illustrates a conceptual diagram of an example system comprising an implantable medical device (IMD) configured to deliver spinal cord stimulation (SCS) therapy and an external programmer.

[0016] Figure 2 This is a block diagram illustrating an example configuration of components of an IMD based on one or more techniques disclosed herein.

[0017] Figure 3 This is a block diagram illustrating an example configuration of components of an external programmer according to one or more techniques disclosed herein.

[0018] Figure 4 This is a graph of an example evoked compound action potential (ECAP) for sensing a corresponding stimulus impulse according to one or more techniques of this disclosure.

[0019] Figure 5A This is a timing diagram illustrating examples of electrical stimulation pulses, corresponding stimulation signals, and corresponding sensed ECAPs according to one or more techniques disclosed herein.

[0020] Figure 5B This is a timing diagram illustrating an example of an electrical stimulation pulse, a corresponding stimulation signal, and a corresponding sensed ECAP, according to one or more techniques disclosed herein.

[0021] Figure 6A This is a timing diagram illustrating examples of electrical stimulation pulses, corresponding stimulation signals, and corresponding sensed ECAPs according to one or more techniques disclosed herein.

[0022] Figure 6B This is a timing diagram illustrating another example of an electrical stimulation pulse, a corresponding stimulation signal, and a corresponding sensed ECAP, based on one or more techniques disclosed herein.

[0023] Figure 7 This is a timing diagram illustrating another example of an electrical stimulation pulse, a corresponding stimulation signal, and a corresponding ECAP, based on one or more techniques of this disclosure.

[0024] Figure 8 This is a timing diagram illustrating another example of an electrical stimulation pulse, a corresponding stimulation signal, and a corresponding ECAP, based on one or more techniques of this disclosure.

[0025] Figure 9 The flowchart illustrates an example operation of controlling stimuli based on one or more sensed ECAPs, according to one or more techniques disclosed herein.

[0026] Figure 10 According to one or more techniques disclosed herein, a voltage / current / time graph is shown, which plots the control pulse current amplitude, notification pulse current amplitude, ECAP voltage amplitude, and second ECAP voltage amplitude as a function of time.

[0027] Figure 11 The flowchart illustrates an example operation of controlling stimuli based on one or more sensed ECAPs, according to one or more techniques disclosed herein.

[0028] Figure 12 Voltage / current / time graphs are shown according to one or more techniques disclosed herein, the graphs plotting the amplitude of the control pulse current, the amplitude of the notification pulse current, and the amplitude of the ECAP voltage as a function of time.

[0029] Figure 13 The present disclosure illustrates a block diagram of a system for determining a control strategy for an IMD, based on one or more techniques.

[0030] Figure 14 It demonstrates one or more techniques according to this disclosure for adjusting Figure 1 A flowchart illustrating an example operation of the control strategy for IMD.

[0031] Figure 15 The flowchart illustrates an example operation for generating recommended procedures for controlling one or more treatment parameters, based on one or more techniques disclosed herein.

[0032] Figure 16 This disclosure illustrates one or more techniques for outputting one or more requests and receiving one or more responses to adjust the output by... Figure 1A flowchart illustrating an example of how the IMD stimulates a patient.

[0033] Figures 17A to 17B The flowchart illustrates example operations for outputting one or more requests and receiving one or more responses, based on one or more techniques disclosed herein.

[0034] Figure 18 The flowchart illustrates an example of storing one or more histogram datasets based on one or more techniques disclosed herein.

[0035] Figure 19 It demonstrates, based on one or more techniques of this disclosure, that by Figure 1 A graph showing the ECAP magnitude of a set of ECAPs sensed by the IMD.

[0036] Figure 20 This disclosure illustrates one or more techniques including those related to... Figure 19 A chart of histogram data corresponding to the curve graph.

[0037] The same reference numerals denote the same elements throughout the description and figures. Detailed Implementation

[0038] This disclosure describes examples of medical devices, systems, and techniques for setting or adjusting parameters that define a control strategy, which the medical device uses to automatically adjust stimulation parameters that define electrical stimulation. Thus, the medical device can automatically adjust the electrical stimulation therapy delivered to the patient based on the control strategy and one or more characteristics of evoked compound action potentials (ECAPs) received by the medical device. This disclosure also describes one or more techniques for adjusting a control strategy that the medical device uses to adjust stimulation parameter values ​​that define electrical stimulation therapy. Electrical stimulation therapy is typically delivered to a patient's target tissue (e.g., one or more nerves or muscles) via two or more electrodes. Parameters of the electrical stimulation therapy (e.g., electrode combination, voltage or current amplitude, pulse width, pulse frequency, etc.) are selected by the clinician and / or patient to relieve various symptoms, such as pain, muscle dysfunction, etc.

[0039] However, the distance between the electrodes and the target tissue changes as the patient moves. Postural changes or patient activity may cause the electrodes to move closer to or further away from the target nerve. The migration of the lead over time may also alter the distance between the electrodes and the target tissue. In some cases, transient patient conditions such as coughing, sneezing, laughing, Valsalva maneuvers, leg raises, neck movements, or deep breathing may temporarily cause the stimulating electrodes of the medical device to move closer to the patient's target tissue, thus intermittently altering the patient's perception of electrical stimulation therapy.

[0040] Since neural recruitment is a function of stimulus intensity and the distance between the target tissue and the electrode, moving the electrode closer to the target tissue may lead to increased patient perception (e.g., possible discomfort, unpleasantness, or pain), while moving the electrode away from the target tissue may lead to decreased therapeutic efficacy. For example, if the stimulus remains constant and the stimulating electrode moves closer to the target tissue, the patient may perceive the stimulus as stronger, more uncomfortable, or even painful. Conversely, consistent stimulation when the electrode moves away from the target tissue may result in less intense stimulation perceived by the patient, which may reduce the therapeutic effect. Discomfort or pain caused by transient patient conditions may be referred to herein as “transient overstimulation.” Therefore, in some cases, adjusting the stimulus parameters in response to patient movement or other conditions that may lead to transient overstimulation may be beneficial.

[0041] ECAP can be induced by stimulating pulses delivered to the patient's nerve fibers. After being induced, the ECAP may propagate along the nerve fiber away from the initial stimulus. In some cases, the sensing circuitry of the medical device can detect this ECAP. The characteristics of the detected ECAP signal may indicate a change in the distance between the electrode and the target tissue. For example, a sharp increase in ECAP amplitude over a short period of time (e.g., less than one second) may indicate a decrease in the distance between the electrode and the target tissue due to transient patient movements (e.g., coughing). A gradual increase in ECAP amplitude over a longer period of time (e.g., days, weeks, or months) may indicate a decrease in the distance between the electrode and the target tissue due to long-term lead migration after the medical device has been implanted. Adjusting one or more treatment parameter values ​​may be beneficial in preventing the patient from experiencing discomfort due to either short-term or long-term electrode movement relative to the target tissue.

[0042] To facilitate the sensing of ECAPs, in some examples, the medical device may deliver pulses (e.g., notification pulses) as part of treatment and also deliver multiple control pulses designed to trigger a detectable ECAP when the notification pulse does not. For example, the duration of the control pulses may be shorter than that of the notification pulses to reduce or eliminate signal artifacts caused by the notification pulses and to prevent or limit the detection of ECAPs received at the sensing electrodes. In certain embodiments, the control pulses are short enough that the pulses end before all or most of the ECAP signal reaches the sensing electrodes(s). In this way, the medical device may interleave multiple control pulses with at least some of the notification pulses. For example, the medical device may deliver notification pulses for a period of time, then deliver control pulses and sense the corresponding ECAP (if any). The medical device may then resume the delivery of notification pulses for another period of time. In some examples, the pulse duration of the control pulses is shorter than that of the notification pulses, and the pulse duration of the control pulses is short enough that the medical device can sense a single ECAP within each control pulse. In some examples, the control pulses may provide or contribute to treatment perceived by the patient.

[0043] As described herein, transient patient movements can cause a temporary change in the distance between the electrode and the target tissue during the corresponding transient patient movement. Such transient patient movements can include one or more rapid movements lasting approximately several seconds or less. During such transient movements, the distance between the electrode and the target tissue may change, affecting the patient's perception of electrical stimulation therapy delivered by the medical device. If the stimulation pulse is constant and the electrode moves closer to the target tissue, the patient may experience a greater or deeper "feeling" or sensation from the treatment. This deepened feeling may be perceived as discomfort or pain (e.g., transient overstimulation) in response to the electrode moving closer to the target tissue. ECAP is a measure of neural recruitment because each ECAP signal represents a superposition of potentials generated in response to axonal firing in response to electrical stimulation (e.g., a stimulation pulse). Variations in the characteristics of the ECAP signal (e.g., the amplitude of a portion of the signal) occur depending on how many axons are activated by the delivered stimulation pulse.

[0044] Since the ECAP can provide an indication of a patient's perception of electrical stimulation therapy, the technology of this disclosure enables a medical device to reduce one or more parameters of the stimulation pulse delivered to the target tissue in response to a first ECAP exceeding a threshold ECAP characteristic value. By reducing one or more parameters of the notification pulse, the medical device can prevent the patient from experiencing transient overstimulation. Subsequently, if the medical device determines that the sensed ECAP later drops below the threshold ECAP characteristic value, the medical device can restore the stimulation pulse to the parameter values ​​set before the medical device reduced the stimulation pulse in response to the threshold ECAP characteristic value exceeding the threshold ECAP characteristic value.

[0045] The technology disclosed herein can provide one or more advantages. For example, it may be beneficial to change the rate at which a medical device decreases and subsequently increases one or more parameters of a stimulation pulse delivered to a target tissue in response to a transient patient action or a change in a control strategy. For example, processing circuitry can execute algorithms that generate one or more recommendations or automatically change one or more parameters defining a control strategy, which controls how the medical device changes stimulation parameters based on physiological signals such as ECAP characteristic values. Based on receiving an indication that the patient experienced transient overstimulation at the onset of a transient patient action, the processing circuitry can increase the rate at which the medical device decreases one or more stimulation parameters defining the stimulation pulse in response to a first ECAP exceeding a threshold ECAP characteristic value. Alternatively, based on receiving an indication that the patient experienced transient overstimulation at the end of a transient patient action, the processing circuitry can decrease the rate at which the medical device increases one or more parameters of the stimulation pulse after decreasing one or more parameters in response to a first ECAP exceeding a threshold ECAP characteristic value. Instead of automatically adjusting the parameters of the control strategy, the system can generate recommendations to be presented to the user to indicate appropriate adjustments to the control strategy. In this way, in some examples, a user, such as a clinician or patient, can accept or confirm the changes in the recommendations.

[0046] Executing an algorithm to output a set of prompts for display on a user interface of an external device can be beneficial, enabling the patient to provide a set of responses indicating various aspects of one or more sensations experienced by the patient. For example, the set of prompts may include prompts that cause the patient to perform an action. Alternatively, the set of prompts may include one or more prompts that allow the patient to characterize one or more sensations before, during, or after the action performed by the patient. Based on this set of responses, processing circuitry may execute an algorithm to provide one or more changes to a control strategy that determines adjustments to stimulation parameters defining the treatment delivered to the target tissue. The processing circuitry may automatically change one or more parameters of the control strategy based on recommendations, but this is not required.

[0047] Additionally, medical devices can capture histogram data for analysis. In some examples, histogram data may include one or more sets of histograms, each of which comprises a set of bins. The histograms may include multiple ECAP amplitudes measured by the medical device over a period of time. A set of histograms may represent a histogram sequence, with each histogram corresponding to a time period (e.g., one second). That is, the first histogram may correspond to a first time period, the second histogram may correspond to a second time period immediately following the first, the third histogram may correspond to a third time period immediately following the second, and so on. Each histogram in the histogram sequence may include a set of "bins," where each bin in the set corresponds to a range of ECAP amplitudes. In this way, the medical device or user can identify the number of times a patient may have experienced transient hyperstimulation based on the changes in the histograms and the histogram sequence over time.

[0048] Medical devices can capture each histogram in one or more sets of histograms based on one or more triggers. For example, a medical device can capture at least one histogram in one or more sets of histograms based on receiving an instruction to capture a set of histograms; a medical device can capture at least one histogram in one or more sets of histograms based on detecting one or more events that trigger the medical device to capture a set of histograms; a medical device can capture at least one histogram in one or more sets of histograms based on a schedule (e.g., daily, hourly, or any other time interval), or any combination thereof. The medical device can save each histogram in one or more sets of histograms to memory, where each histogram in one or more sets of histograms is associated with a timestamp. In this way, processing circuitry can analyze these sets of histograms and the associated timestamps when determining a control strategy to adjust the control strategy to improve the detection of overstimulation events.

[0049] In some examples, the medical device may deliver stimulations including pulses (e.g., control pulses) that aid in treatment and also elicit a detectable ECAP signal. In other examples, the medical device may deliver stimulation pulses to include both control and notification pulses. A nerve impulse can be detected when the ECAP signal propagates rapidly along the nerve fiber after the delivered stimulation pulse initially depolarizes the nerve. Therefore, if the stimulation pulse delivered by the first electrode has too long a pulse width, different electrodes configured to sense the ECAP will sense the stimulation pulse itself as an artifact masking a lower amplitude ECAP signal. However, the ECAP signal loses fidelity as the potential propagates from the electrical stimulation because different nerve fibers propagate the potential at different speeds. Therefore, sensing the ECAP at a distance from the stimulation electrode can avoid artifacts caused by stimulation pulses with long pulse widths, but the ECAP signal may lose the fidelity required to detect changes in the ECAP signal that occur as the distance between the electrode and the target tissue changes. In other words, the system may not be able to identify the ECAP from the stimulation pulse configured to provide treatment to the patient at any distance from the stimulation electrode. Therefore, medical devices can employ control pulses configured to trigger detectable ECAPs and notification pulses that may contribute to the treatment effect on the patient but may not trigger detectable ECAPs.

[0050] In these examples, the medical device is configured to deliver multiple notification pulses configured to provide treatment to a patient and multiple control pulses that may or may not contribute to the treatment. At least some of the control pulses can trigger a detectable ECAP signal, even if the primary purpose is not to provide treatment to the patient. The delivery of control pulses can be interleaved with the delivery of notification pulses. For example, the medical device can deliver notification pulses and control pulses alternately, such that control pulses are delivered between consecutive notification pulses and ECAP signals are sensed. In some examples, multiple control pulses are delivered between consecutive notification pulse deliveries and corresponding ECAP signals are sensed. In some examples, multiple notification pulses are delivered between consecutive control pulses. In any case, notification pulses can be delivered according to a selected predetermined pulse frequency, such that the notification pulses can produce a therapeutic outcome for the patient. Then, one or more control pulses are delivered within one or more time windows between consecutive notification pulses delivered according to the predetermined pulse frequency, and corresponding ECAP signals are sensed. In this way, the medical device can deliver notification pulses uninterruptedly while sensing ECAP from control pulses delivered during periods when no notification pulses are delivered. In other examples described herein, the medical device senses the ECAP in response to a notification pulse delivered by the medical device, while a control pulse is not used to trigger the ECAP.

[0051] Based on the examples described herein, a medical device can be configured to deliver stimulation pulses comprising control pulses or a combination of multiple control pulses and multiple notification pulses. In some cases, the multiple control pulses may be therapeutic and contribute to the treatment received by the patient. In other examples, the multiple control pulses may be non-therapeutic and not contribute to the treatment received by the patient. In other words, a control pulse configured to elicit a detectable ECAP may or may not contribute to alleviating the patient's condition or symptoms of the patient's condition. In contrast to control pulses, notification pulses may not elicit a detectable ECAP, or the system may not utilize the ECAP from the notification pulse as feedback for controlling treatment. Therefore, the medical device or other components associated with the medical device may alternatively determine the values ​​of one or more stimulation parameters that at least partially define the notification pulse based on the ECAP signal elicited by the control pulse. In this way, the notification pulse can be notified by the ECAP elicited from the control pulse. The medical device or other components associated with the medical device may determine the values ​​of one or more stimulation parameters that at least partially define the control pulse based on the ECAP signal elicited by a previous control pulse.

[0052] Although electrical stimulation is typically described herein as an electrical stimulation pulse, it can be delivered in a non-pulse form in other examples. For instance, electrical stimulation can be delivered as a signal with various waveform shapes, frequencies, and amplitudes. Thus, electrical stimulation in the form of a non-pulse signal can be a continuous signal, possibly with a sinusoidal waveform or other continuous waveforms.

[0053] Figure 1 This disclosure illustrates a conceptual diagram of an example system 100, comprising an implantable medical device (IMD) 110 configured to deliver spinal cord stimulation (SCS) therapy and an external programmer 150, based on one or more techniques. While the techniques described in this disclosure are generally applicable to a wide range of medical devices, including external devices and IMDs, for illustrative purposes, the application of such techniques to IMDs, and more specifically, to implantable electrical stimulators (e.g., neurostimulators), will be described. More specifically, for illustrative purposes, this disclosure relates to implantable SCS systems, but is not limited to other types of medical devices or other therapeutic applications of medical devices.

[0054] like Figure 1 As shown, system 100 includes IMD 110, leads 130A and 130B, and an external programmer 150 shown with patient 105 (which is typically a human patient). Figure 1In one example, IMD 110 is an implantable electrical stimulator configured to generate and deliver electrical stimulation therapy to patient 105 via one or more electrodes of leads 130A and / or 130B (collectively, “leads 130”), for example, to relieve chronic pain or other symptoms. In other examples, IMD 110 may be coupled to a single lead carrying multiple electrodes or more than two leads, each carrying multiple electrodes. As part of the stimulation pulses delivering the electrical stimulation therapy, IMD 110 may be configured to generate and deliver control pulses configured to trigger an ECAP signal. In some examples, the control pulses may provide therapy. In other examples, IMD 110 may deliver notification pulses that aid in patient treatment but do not trigger a detectable ECAP. IMD 110 may be a chronic electrical stimulator that remains implanted in patient 105 for weeks, months, or even years. In other examples, IMD 110 may be a temporary or experimental stimulator used to screen or evaluate the efficacy of electrical stimulation for chronic treatment. In one example, the IMD 110 is implanted in patient 105, while in another example, the IMD 110 is an external device coupled to a percutaneously implanted lead. In some examples, the IMD 110 uses one or more leads, while in others, the IMD 110 is leadless.

[0055] IMD 110 can be made of components sufficient to mount IMD 110 (e.g., Figure 2 The component shown may be constructed from any polymer, metal, or composite material housed within the patient 105. In this example, the IMD 110 may be constructed with a biocompatible shell (such as titanium or stainless steel) or a polymeric material (such as silicone, polyurethane, or liquid crystal polymer) and surgically implanted into a site near the pelvis, abdomen, or buttocks of the patient 105. In other examples, the IMD 110 may be implanted into other suitable sites within the patient 105, depending on, for example, the target site within the patient 105 where electrical stimulation therapy needs to be delivered. The shell of the IMD 110 may be configured to provide an hermetically sealed component, such as a rechargeable or non-rechargeable power source. Additionally, in some examples, the shell of the IMD 110 is selected from materials that facilitate the reception of energy to charge a rechargeable power source.

[0056] For example, electrical stimulation energy (which may be pulses based on constant current or constant voltage) is delivered from the IMD 110 to one or more target tissue sites in the patient 105 via one or more electrodes (not shown) of the implanted lead 130. Figure 1In one example, lead 130 carries an electrode positioned near the target tissue, the spinal cord 120. One or more electrodes may be positioned at the distal end of lead 130 and / or at other locations along the midpoint of lead 130. Lead 130 may be implanted and coupled to IMD 110. The electrodes may deliver electrical stimulation generated by an electrical stimulation generator in IMD 110 to the tissue of patient 105. Although each lead 130 may be a single lead, lead 130 may include lead extensions or other segments that may facilitate implantation or positioning of lead 130. In some other examples, IMD 110 may be a leadless stimulator with one or more electrode arrays disposed on a stimulator housing rather than on leads extending from the housing. Additionally, in some other examples, system 100 may include one or more leads, each coupled to IMD 110 and guided to similar or different target tissue sites.

[0057] The electrodes of lead 130 may be electrode pads on a paddle-shaped lead, circular (e.g., annular) electrodes surrounding the lead body, adhesive electrodes, cuff electrodes, segmented electrodes (e.g., electrodes positioned at different circumferential locations on the lead instead of a continuous annular electrode), any combination thereof (e.g., annular and segmented electrodes), or any other type of electrode capable of forming a combination of monopolar, bipolar, or multipolar electrodes for treatment. Annular electrodes positioned at different axial locations at the distal end of lead 130 will be described for illustrative purposes.

[0058] Electrodes have been described via lead 130 for illustrative purposes, but electrode arrays can be deployed in different ways. For example, a housing associated with a leadless stimulator can carry an electrode array, for example, in rows and / or columns (or other patterns), to which displacement operations can be applied. Such electrodes can be arranged as surface electrodes, ring electrodes, or protrusions. Alternatively, the electrode array can be formed from rows and / or columns of electrodes on one or more paddle-shaped leads. In some examples, the electrode array includes electrode segments arranged at corresponding locations on the periphery of the leads, for example, arranged as one or more segmented rings on the circumference of a cylindrical lead. In other examples, one or more leads 130 are linear leads with eight ring electrodes along the axial length of the lead. In yet another example, the electrodes are segmented rings arranged linearly along the axial length of the lead and on the periphery of the lead.

[0059] The stimulation parameters defining the therapeutic stimulation program for electrical stimulation therapy via electrodes of lead 130 using the IMD 110 may include information identifying which electrodes have been selected for delivering stimulation according to the stimulation program, the polarity of the selected electrodes (i.e., the electrode combination of the program), and the voltage or current amplitude, pulse frequency, pulse width, and pulse shape of the stimulation delivered by the electrodes. These stimulation parameters of the stimulation pulses (e.g., control pulses and / or notification pulses) are typically predetermined parameter values ​​determined before the delivery of the stimulation pulses (e.g., set according to the stimulation program). However, in some examples, system 100 automatically changes one or more parameter values ​​based on one or more factors or based on user input and / or control strategies.

[0060] ECAP test stimulation procedures can define stimulation parameter values ​​that define control pulses delivered by the IMD 110 through at least some electrodes of the lead 130. These stimulation parameter values ​​may include information identifying which electrodes have been selected for delivering control pulses, the polarity of the selected electrodes (i.e., the electrode combination of the procedure), and the voltage or current amplitude, pulse frequency, pulse width, and pulse shape of the stimulation delivered by the electrodes. The stimulation signal (e.g., one or more stimulation pulses or a continuous stimulation waveform) defined by the parameters of each ECAP test stimulation procedure is configured to induce compound action potentials from the nerve. In some examples, the ECAP test stimulation procedure defines when to deliver control pulses to the patient based on the frequency and / or pulse width of the notification pulse, when a notification pulse is also delivered. In some examples, the stimulation defined by each ECAP test stimulation procedure is not intended to provide or facilitate treatment for the patient. In other examples, the stimulation defined by each ECAP test stimulation procedure may facilitate treatment when the control pulse elicits a detectable ECAP signal and facilitates treatment. In this way, the ECAP test stimulation procedure can define stimulation parameters that are the same as or similar to the stimulation parameters of a treatment stimulation procedure.

[0061] although Figure 1 This relates to SCS therapy, for example, for treating pain, but in other examples, system 100 can be configured to treat any other condition that can benefit from electrical stimulation therapy. For example, system 100 can be used to treat tremor, Parkinson's disease, epilepsy, pelvic floor dysfunction (e.g., urinary incontinence or other bladder dysfunction, fecal incontinence, pelvic pain, bowel dysfunction, or sexual dysfunction), obesity, gastroparesis, or mental disorders (e.g., depression, mania, obsessive-compulsive disorder, anxiety, etc.). In this way, system 100 can be configured to provide therapy in the form of deep brain stimulation (DBS), peripheral nerve stimulation (PNS), peripheral nerve field stimulation (PNFS), cortical stimulation (CS), pelvic floor stimulation, gastrointestinal stimulation, or any other stimulation therapy capable of treating the condition of patient 105.

[0062] In some examples, lead 130 includes one or more sensors configured to allow IMD 110 to monitor one or more parameters of patient 105, such as patient activity, pressure, temperature, or other characteristics. One or more sensors may be provided to supplement or replace the therapeutic delivery of lead 130.

[0063] The IMD 110 is configured to deliver electrical stimulation therapy to a patient 105, either alone or in combination with electrodes carried or defined by the housing of the IMD 110, via one or two leads 130. The target tissue for the electrical stimulation therapy can be any tissue affected by electrical stimulation, which can take the form of pulses or continuous waveforms. In some examples, the target tissue includes nerves, smooth muscle, or skeletal muscle. Figure 1 In the example shown, the target tissue is tissue near the spinal cord 120, such as within the intrathecal or epidural space of the spinal cord 120, or, in some examples, adjacent nerves branching off from the spinal cord 120. The lead 130 can be introduced into the spinal cord 120 via any suitable region (e.g., the thoracic, cervical, or lumbar region). Stimulation of the spinal cord 120, for example, can prevent pain signals from propagating through the spinal cord 120 and reaching the brain of the patient 105. The patient 105 can perceive the interruption of the pain signal as pain relief, and thus as an effective therapeutic outcome. In other examples, stimulation of the spinal cord 120 can produce sensory abnormalities, which can reduce the patient 105's perception of pain and thus provide an effective therapeutic outcome.

[0064] The IMD 110 generates electrical stimulation therapy according to one or more therapeutic stimulation programs and delivers it to a target stimulation site within the patient 105 via electrodes connected to a lead 130 to the patient 105. The therapeutic stimulation program defines values ​​for one or more parameters that define one aspect of the therapy delivered by the IMD 110 according to the program. For example, a therapeutic stimulation program that controls the IMD 110 to deliver stimulation in pulses can define values ​​for the voltage or current pulse amplitude, pulse width, and pulse rate (e.g., pulse frequency) of the stimulation pulses delivered by the IMD 110 according to the program.

[0065] In some examples where the ECAP signal cannot be detected from the types of pulses intended to be delivered to provide treatment to the patient, control pulses and notification pulses may be delivered. For example, IMD 110 is configured to deliver control stimulation to patient 105 individually or in combination with electrodes carried or defined by the housing of IMD 110 via an electrode combination of lead 130. The tissue targeted by the control stimulation may be the same tissue targeted by the electrical stimulation therapy, but IMD 110 may deliver control stimulation pulses via the same electrodes, at least some of the same electrodes, or different electrodes. Because the control stimulation pulses are delivered in an interleaved manner with the notification pulses, clinicians and / or users can select any desired electrode combination for the notification pulses. As with electrical stimulation therapy, the control stimulation may be in the form of electrical stimulation pulses or continuous waveforms. In one example, each control stimulation pulse may include a balanced biphasic square wave pulse employing an active charging phase. However, in other examples, the control stimulation pulse may include a monophasic pulse followed by a passive charging phase. In other examples, the control pulse may include an unbalanced biphasic portion and a passive charging portion. Although not strictly necessary, biphasic control pulses may include an interphase interval between the positive and negative phases to facilitate the propagation of nerve impulses in response to the first phase of the biphasic pulse. Control stimulation can be delivered without interrupting the delivery of electrical stimulation notification pulses, such as during a window between consecutive notification pulses. Control pulses can induce ECAP signals from tissue, and the IMD 110 can sense the ECAP signals via two or more electrodes on the lead 130. When control stimulation pulses are applied to the spinal cord 120, the IMD 110 can sense the signal from the spinal cord 120.

[0066] The IMD 110 can deliver control stimulation to a target stimulation site within the patient 105 via electrodes of lead 130 according to one or more ECAP test stimulation programs. One or more ECAP test stimulation programs can be stored in the storage device of the IMD 110. Each of the one or more ECAP test stimulation programs includes values ​​for one or more parameters that define one aspect of the control stimulation delivered by the IMD 110 according to that program, such as current or voltage amplitude, pulse width, pulse frequency, electrode combination, and, in some examples, timing based on a notification pulse to be delivered to the patient 105. In some examples, the IMD 110 delivers control stimulation to the patient 105 according to multiple ECAP test stimulation programs.

[0067] A user (e.g., a clinician or patient 105) can interact with the user interface of an external programmer 150 to program the IMD 110. Programming the IMD 110 can generally refer to generating and transmitting commands, programs, or other information for controlling the operation of the IMD 110. In this way, the IMD 110 can receive transmitted commands and programs from the external programmer 150 to control electrical stimulation therapy (e.g., notification pulses) and control stimulation (e.g., control pulses). For example, the external programmer 150 can transmit treatment stimulation programs, ECAP test stimulation programs, stimulation parameter adjustments, treatment stimulation program selection, ECAP test program selection, user input, or other information for controlling the operation of the IMD 110, for example, via wireless telemetry or a wired connection. As described herein, stimulation delivered to the patient may include control pulses, and in some examples, stimulation may include both control pulses and notification pulses.

[0068] In some cases, if the external programmer 150 is primarily intended for use by a physician or clinician, it can be characterized as a physician or clinician programmer. In other cases, if the external programmer 150 is primarily intended for use by a patient, it can be characterized as a patient programmer. The patient programmer is typically accessible to the patient 105 and, in many cases, can be a portable device that accompanies the patient 105 throughout their daily life. For example, the patient programmer can receive input from the patient 105 when the patient wishes to terminate or change electrical stimulation therapy. Typically, a physician or clinician programmer can support the clinician in selecting and generating programs for use by the IMD 110, while a patient programmer can support the patient in adjusting and selecting these programs during normal use. In other examples, the external programmer 150 may include, or be part of, an external charging device for powering the IMD 110. In this way, a user can program and charge the IMD 110 using one or more devices.

[0069] As described herein, information can be transmitted between the external programmer 150 and the IMD 110. Therefore, the IMD 110 and the external programmer 150 can communicate wirelessly using any technology known in the art. Examples of communication technologies may include, for example, radio frequency (RF) telemetry and inductive coupling, but other technologies are also contemplated. In some examples, the external programmer 150 includes a communication head that can be placed near the patient's body close to the IMD 110 implantation site to improve the quality or security of communication between the IMD 110 and the external programmer 150. Communication between the external programmer 150 and the IMD 110 can occur during or separate from power transmission.

[0070] In some examples, in response to commands from an external programmer 150, the IMD 110 delivers electrical stimulation therapy to a target tissue site on the spinal cord 120 of the patient 105 via electrodes (not depicted) on lead 130 according to multiple therapeutic stimulation programs. In some examples, the IMD 110 can modify the therapeutic stimulation programs as the patient 105's treatment needs evolve over time. For example, modification of the therapeutic stimulation programs can result in adjustment of at least one parameter of multiple notification pulses. The efficacy of the treatment may decrease when the patient 105 receives the same treatment over extended periods. In some cases, the parameters of the multiple notification pulses can be updated automatically.

[0071] In this disclosure, the efficacy of electrical stimulation therapy can be indicated by one or more characteristics of the action potentials induced by stimulation pulses delivered by the IMD 110 (e.g., the amplitude of one or more peaks, the amplitude between one or more peaks, or the area under the curve of one or more peaks) (i.e., characteristics of the ECAP signal). Electrical stimulation therapy delivered via the leads 130 of the IMD 110 may induce compound action potentials in neurons within the target tissue, which propagate up and down from the target tissue and ultimately reach the sensing electrodes of the IMD 110. Furthermore, controlled stimulation can also induce at least one ECAP, and the ECAP in response to controlled stimulation can also be a surrogate indicator of therapeutic efficacy. The amount of induced action potentials (e.g., the number of neurons propagating the action potential signal) can be based on various parameters of the electrical stimulation pulse, such as amplitude, pulse width, frequency, pulse shape (e.g., the switching rate at the start and / or end of the pulse), etc. The switching rate can be defined as the rate of change of the voltage and / or current amplitude of the pulse at the start and / or end of each phase of each pulse or within a pulse. For example, a very high slew rate indicates a steep, even near-vertical, pulse edge, while a low slew rate indicates a longer rise (or fall) in pulse amplitude. In some examples, these parameters contribute to the intensity of the electrical stimulation. Additionally, the characteristics of the ECAP signal (e.g., amplitude) may vary based on the distance between the stimulating electrode and the nerve affected by the electric field generated by the delivered controlled stimulation pulse.

[0072] In one example, each treatment pulse may have a pulse width greater than approximately 300 μs, for example, between approximately 300 μs and 1000 μs (i.e., 1 ms) in some examples. At these pulse widths, the IMD 110 may not be able to adequately detect the ECAP signal because the treatment pulse is also detected as an artifact masking the ECAP signal. If the ECAP is not adequately recorded, the ECAP arriving at the IMD 110 cannot be compared to the target ECAP characteristics (e.g., target ECAP amplitude), and the electrotherapy stimulation cannot be changed based on the responsive ECAP. When the notification pulse has these longer pulse widths, the IMD 110 can deliver control stimulation in the form of control pulses. Control pulses may have pulse widths less than approximately 300 μs, such as biphasic pulses with a duration of approximately 100 μs per phase. Because the control pulses may have shorter pulse widths than the notification pulses, ECAP signals can be sensed and identified after each control pulse, and these signals can be used to notify the IMD 110 of any changes that should be made to the notification pulses (and, in some examples, the control pulses). Typically, the term "pulse width" refers to the total duration of each phase of a single pulse, plus the phase-to-phase intervals when appropriate. A single pulse may include a single phase in some examples (i.e., a single-phase pulse) or two or more phases in others (e.g., a biphase or triphase pulse). The pulse width defines the time period from the start time of the first phase of the pulse to the end time of the last phase of the pulse (e.g., a biphase pulse with a 100 μs positive phase, a 100 μs negative phase, and a 30 μs phase-to-phase interval defines a pulse width of 230 μs). In another example, a control pulse may include a 90 μs positive phase, a 90 μs negative phase, and a 30 μs phase-to-phase interval to define a pulse width of 210 μs. In yet another example, a control pulse may include a 120 μs positive phase, a 120 μs negative phase, and a 30 μs phase-to-phase interval to define a pulse width of 270 μs.

[0073] As described, an example technique for adjusting the stimulation parameter values ​​of the notification pulse is based on comparing the characteristic values ​​of a measured ECAP signal with the characteristic values ​​of a target ECAP. During the delivery of a control stimulation pulse defined by one or more ECAP testing stimulation procedures, the IMD 110 senses the potentials of tissues of the spinal cord 120 of the patient 105 via two or more electrodes placed on lead 130 to measure the electrical activity of the tissue. The IMD 110, for example, utilizes electrodes on one or more leads 130 and associated sensing circuitry to sense the ECAP from the target tissue of the patient 105. In some examples, the IMD 110 receives signals indicative of the ECAP from one or more sensors (e.g., one or more electrodes and circuits) inside or outside the patient 105. Such example signals may include signals indicative of the ECAP of the tissues of the patient 105. Examples of the one or more sensors include one or more sensors configured to measure the compound action potential of the patient 105 or indicative of the physiological effects of the compound action potential. For example, to measure the physiological effects indicative of a compound action potential (ECAP), one or more sensors may be an accelerometer, a pressure sensor, a flexure sensor, a sensor configured to detect the posture of patient 105, or a sensor configured to detect the respiratory function of patient 105. In this way, while the ECAP may indicate postural changes or other patient movements, other sensors may also detect similar postural changes or movements using modalities separate from the ECAP. However, in other examples, the external programmer 150 receives a signal indicating a compound action potential in target tissue of patient 105 and transmits the notification to the IMD 110.

[0074] In the example technology described in this disclosure, the control of stimulation parameters and target ECAP characteristic values ​​can initially be set in the clinic, but can be set and / or adjusted by the patient 105 at home. Once the target ECAP characteristic value is set, the example technology allows for automatic adjustment of treatment pulse parameters to maintain a consistent level of neural activation and consistent treatment perception for the patient as the distance between the electrode and the neuron changes. The ability to change the stimulation parameter values ​​also allows for long-term therapeutic efficacy, enabling the intensity of stimulation (e.g., as indicated by the ECAP) to remain consistent by comparing the measured ECAP value with the target ECAP characteristic value. IMD 110 can perform these changes without intervention from the physician or patient 105.

[0075] In some examples, the system changes the target ECAP characteristic value over a period of time. The system can be programmed to change the target ECAP characteristic to adjust the intensity of the notification pulse, thereby providing the patient with different sensations (e.g., increasing or decreasing neural activation). In one example, the system can be programmed to cause the target ECAP characteristic value to oscillate at a predetermined frequency between a maximum and a minimum target ECAP characteristic value to provide the patient with a sensation that can be perceived as a wave or other sensations that can provide therapeutic relief. The maximum target ECAP characteristic value, the minimum target ECAP characteristic value, and the predetermined frequency can be stored in the storage device of IMD 110 and can be updated in response to signals from external programmer 150 (e.g., user requests to change values ​​stored in the storage device of IMD 110). In other examples, the target ECAP characteristic value can be programmed to steadily increase or steadily decrease to a baseline target ECAP characteristic value over a period of time. In other examples, external programmer 150 can be programmed to automatically change the target ECAP characteristic value over time according to other predetermined functions or patterns. In other words, the target ECAP characteristic value can be programmed to change incrementally by a predetermined amount or percentage, said predetermined amount or percentage being selected according to a predetermined function (e.g., a sine function, ramp function, exponential function, logarithmic function, etc.). The increment for changing the target ECAP characteristic value can be varied for each specific number of pulses or a specific time unit. Although the system can change the target ECAP characteristic value, the received ECAP signal can still be used by the system to adjust one or more parameter values ​​of the notification pulse and / or control pulse to meet the target ECAP characteristic value.

[0076] In some examples, IMD 110 includes stimulation generation circuitry configured to deliver electrical stimulation therapy to patient 105, wherein the electrical stimulation therapy comprises a plurality of notification pulses. Additionally, the stimulation generation circuitry of IMD 110 may be configured to deliver a plurality of control pulses, wherein the plurality of control pulses are interleaved with at least some of the notification pulses. In some examples, IMD 110 includes sensing circuitry configured to detect a plurality of ECAPs, wherein the sensing circuitry is configured to detect each of the plurality of ECAPs after one of the control pulses and before a subsequent treatment pulse of the plurality of notification pulses. Although IMD 110 may receive a plurality of ECAPs based on the delivery of a plurality of control pulses (e.g., the plurality of control pulses may induce a plurality of ECAPs received by IMD 110), the plurality of ECAPs may indicate the efficacy of the plurality of notification pulses. In other words, although in some cases the plurality of ECAPs may not be induced by the plurality of notification pulses themselves, the plurality of ECAPs may still reveal one or more characteristics of the plurality of notification pulses or one or more effects of the plurality of notification pulses on patient 105. In some examples, IMD 110 delivers multiple notification pulses at a level above the perception threshold, wherein the patient 105 is able to perceive the multiple notification pulses delivered at the level above the perception threshold. In other examples, IMD 110 delivers multiple notification pulses at a level below the perception threshold, wherein the patient 105 is unable to perceive the multiple notification pulses delivered at the level below the perception threshold.

[0077] IMD 110 may include processing circuitry configured in some examples to process multiple ECAPs received by the sensing circuitry of IMD 110. For example, the processing circuitry of IMD 110 is configured to determine whether a parameter of a first ECAP is greater than a threshold parameter value. The processing circuitry may monitor a characteristic value of each of the multiple ECAPs, and the first ECAP may be the first ECAP among the multiple ECAPs recorded by IMD 110 that exceeds the threshold characteristic value. In some examples, the characteristic monitored by IMD 110 may be the ECAP amplitude. In some examples, the ECAP amplitude may be given by the voltage difference between the peak value of N1 ECAP and the peak value of P2 ECAP. Further description relating to the peak value of N1 ECAP and other ECAP peak values ​​is provided below. Figure 4 The description can be found therein. In other examples, the IMD 110 can monitor one or more characteristics of multiple ECAPs, such as current amplitude, slope, slew rate, ECAP frequency, ECAP duration, or any combination thereof. In some examples where the characteristic includes ECAP amplitude, the threshold ECAP characteristic value can be selected from a range of approximately 5 microvolts (μV) to approximately 30 μV.

[0078] If the processing circuitry of IMD 110 determines that the characteristic of the first ECAP is greater than a threshold ECAP characteristic value, the processing circuitry may decrement (or reduce) the parameters of a set of notification pulses delivered by the stimulation generation circuitry after the first ECAP. In some examples, to decrement the parameters of the set of notification pulses, IMD 110 may reduce the current amplitude of each treatment pulse in each successive treatment pulse of the set of notification pulses by a certain current amplitude value. In other examples, to decrement the parameters of the set of notification pulses, IMD 110 may reduce the amplitude of parameters other than current (e.g., voltage). Since multiple ECAPs can indicate some effect of the treatment delivered by IMD 110 on patient 105, IMD 110 may decrement the parameters of the set of notification pulses to improve the treatment delivered to patient 105. In some cases, an ECAP received by IMD 110 exceeding a threshold ECAP characteristic value may indicate to IMD 110 that one or more leads 130 have moved close to the target tissue (e.g., spinal cord 120) of patient 105. In these cases, if the treatment delivered to the spinal cord 120 remains at the current level, the patient 105 may experience transient overstimulation because the distance between the lead 130 and the target tissue of the patient 105 is a factor in determining the effect of electrical stimulation treatment on the patient 105. Therefore, reducing the first set of notification pulses based on determining that the first ECAP exceeds the threshold ECAP characteristic value can prevent the patient 105 from experiencing transient overstimulation due to electrical stimulation treatment delivered by the IMD 110.

[0079] After determining that the first ECAP exceeds the threshold ECAP characteristic value, the processing circuitry of IMD 110 can continue to monitor multiple ECAPs detected by the sensing circuitry. In some examples, the processing circuitry of IMD 110 can identify a second ECAP occurring after the first ECAP, wherein the characteristic of the second ECAP is less than the threshold ECAP characteristic value. In some cases, the second ECAP can be the first ECAP occurring after the first ECAP whose characteristic value is less than the threshold ECAP characteristic value. In other words, the characteristic value of each ECAP occurring between the first and second ECAPs can be greater than or equal to the threshold ECAP characteristic value. In this way, since IMD 110 can decrement the notification pulses delivered to the patient 105 between the first and second ECAPs, the risk of the patient 105 experiencing transient overstimulation during the extended time period between the reception of the first and second ECAPs is reduced. Based on the fact that the characteristic of the second ECAP is less than the threshold ECAP characteristic value, the processing circuitry of IMD 110 can increment the parameters of a second set of notification pulses delivered by the stimulation generation circuitry after the second ECAP.

[0080] In some examples, the IMD 110 can deliver electrical stimulation therapy to patient 105 based on a "control strategy." In some examples, the IMD 110 stores the control strategy in memory. Figure 1 (Not shown in the image). The control strategy can be set and / or updated by the processing circuitry of the IMD 110 or the processing circuitry of the external programmer 150, the processing circuitry of one or more other devices, or any combination thereof. The control strategy drives one or more treatment configurations of electrical stimulation therapy delivered by the IMD 110. For example, the control strategy can determine the amplitude of one or more stimulation pulses delivered by the IMD 110, the frequency of electrical stimulation therapy delivered by the IMD 110, the response to one or more detected ECAPs (e.g., changes in pulse amplitude and / or pulse frequency), or any combination thereof.

[0081] External programmer 150 or another device may include a user interface. Processing circuitry (e.g., processing circuitry of external programmer 150 and / or processing circuitry of IMD 110) may output a message requesting patient 105 to perform a set of actions for display on the user interface. The processing circuitry may receive user input from the user interface indicating a patient response associated with that set of actions. Additionally, the processing circuitry may determine one or more adjustments to a control strategy based on the user input, the control strategy controlling the electrical stimulation delivered by IMD 110 based on at least one evoked compound action potential (ECAP) sensed by IMD 110.

[0082] In some examples, in response to determining one or more adjustments to the control strategy, the processing circuitry is configured to output instructions for configuring one or more adjustments to the control strategy to the IMD 110 via the communication circuitry of the external programmer 150, but this is not required. The one or more adjustments may be implemented in other ways.

[0083] In some examples, to determine one or more adjustments to the control strategy, the processing circuitry is configured to determine one or more adjustments such that the control strategy performs any one or a combination of the following: decreasing the decrement step size or decrement step rate of a plurality of stimulation pulses delivered to the IMD 110 in response to one or more events associated with a patient response; increasing the decrement step size or decrement step rate of a plurality of stimulation pulses in response to one or more events associated with a patient response; decreasing the increment step size or increment step rate of a plurality of stimulation pulses in response to one or more events associated with a patient response; or increasing the increment step size or increment step rate of a plurality of stimulation pulses in response to one or more transient events associated with a patient response. The one or more adjustments to the control strategy are not intended to be limited to these examples. Adjustments to the control strategy can cause any kind of change in the control strategy toward treatment delivered to the patient 105 by the IMD 110 or another device.

[0084] The message requesting the patient 105 to perform a set of actions, and the user input instructing the patient to respond, associated with the assessment technology, are referred to herein as a "patient guidance wizard" (e.g., a method for providing and receiving information from a user (e.g., a clinician and / or patient) using a user interface to set up stimulation therapy and / or control strategies for treatment). The patient guidance wizard can represent a technology that outputs messages requesting the patient 105 to perform actions (e.g., arching the back, coughing, or other actions) on behalf of the processing circuitry. Subsequently, to execute the patient guidance wizard, the processing circuitry can output a set of requests and receive a set of responses to those requests via a user interface of an external programmer 150 or another device. Each request in the set of requests may include prompts for obtaining information related to one or more patient sensations corresponding to the action, and each response may include information related to the corresponding request. Based on the set of responses received from the user interface, the processing circuitry can determine one or more adjustments to be made to the treatment delivered to the patient 105.

[0085] In some examples, the stimulation generation circuitry of the IMD 110 is configured to deliver electrical stimulation to the patient 105, wherein the electrical stimulation therapy comprises multiple stimulation pulses. Additionally, the IMD 110 may include sensing circuitry configured to sense one or more evoked compound action potentials (ECAPs), wherein the sensing circuitry is configured to sense each of the one or more ECAPs induced by a corresponding stimulation pulse from the plurality of stimulation pulses. The processing circuitry of the IMD 110 may store histogram data corresponding to a set of ECAPs from the plurality of ECAPs sensed by the sensing circuitry of the IMD 110 within a certain time window.

[0086] In some examples, histogram data comprises a set of histograms. Each histogram in this set comprises a set of histogram bins. Each histogram bin in this set corresponds to a range of ECAP parameter values, and each histogram bin in this set includes a number of ECAPs associated with parameter values ​​within the corresponding range of ECAP parameter values ​​from the set of ECAPs. The number of ECAPs in each histogram bin can be any number greater than or equal to zero. The set of histograms can represent a histogram sequence, where each histogram in the histogram sequence corresponds to a set of ECAPs detected by IMD 110 during a corresponding time period. For example, a histogram dataset can include a histogram sequence where each histogram in the histogram sequence corresponds to a one-second time window. That is, the first histogram in the histogram sequence corresponds to the first one-second window, the second histogram in the histogram sequence corresponds to the second one-second window immediately following the first one-second window, and so on. However, the histogram sequence can correspond to a time period of any length.

[0087] In some examples, the processing circuitry of IMD 110 may receive user input from an external device (e.g., an external programmer 150). IMD 110 may capture histogram data from a “rolling buffer” in response to receiving user input and store the captured histogram data in memory. Alternatively, IMD 110 may capture histogram data from the rolling buffer in response to detecting a pattern of interest in a set of ECAPs, detecting a pattern in an accelerometer signal, detecting a state change in an algorithm, or detecting noise in any one or more of IMD 110’s signals. The histogram dataset may include data representing patient responses. That is, IMD 110 may store histogram data in a “rolling buffer” that is updated over time. In some cases, IMD 110 may erase data from the end of the rolling buffer and add data to the beginning of the rolling buffer over time. When IMD 110 receives user input (which may represent a request to capture histogram data from the rolling buffer), IMD 110 may capture or permanently store the histogram data currently in the rolling buffer at the time IMD 110 received the user request.

[0088] In some examples, the IMD 110 can permanently store histogram data without first capturing it in a rolling buffer. For instance, the IMD 110 can receive user reports of the start of patient activity and store a first timestamp corresponding to the start of the patient activity. Additionally, the IMD 110 can receive user reports of the end of patient activity and store a second timestamp corresponding to the end of the patient activity, where the first timestamp corresponds to one of multiple second histogram datasets and the second timestamp corresponds to one of multiple second histogram datasets. The IMD 110 can analyze the stored histogram data based on the timestamps.

[0089] The rolling buffer can correspond to a time window extending from a first time to a second time, where the second time represents the current time and the first time represents a point in time prior to the current time, and where the second time represents the current time or some future time. When the IMD 110 receives user input to capture histogram data in the rolling buffer, the IMD 110 can capture the histogram data currently stored in the rolling buffer, and this histogram data can correspond to the time period in which the patient response occurred. That is, the histogram data can include one or more indicators (e.g., an increased ECAP amplitude) that indicate a patient response such as transient overstimulation.

[0090] The IMD 110 can receive user requests to set one or more histogram parameters for collecting histogram datasets. The one or more histogram parameters may include the length of the time period corresponding to each histogram within the histogram data, a range of ECAP parameters corresponding to each histogram bin, or any other parameters associated with the histogram data. The IMD 110 can set one or more histogram parameters based on user requests, wherein the one or more histogram parameters include a set of parameter ranges that define one or more histogram bins included in a set of histogram bins within the histogram data.

[0091] The histogram data may include: a first set of histograms corresponding to the amplitude values ​​of a set of stimulus pulses delivered by the stimulus generation circuit; and a second set of histograms corresponding to the amplitude values ​​of the ECAP sensed by the sensing circuit in response to the set of stimulus pulses delivered by the stimulus generation circuit. In this way, when evaluating the second set of histograms including the ECAP amplitude values, the processing circuit can evaluate the ECAP amplitude values ​​based on the amplitude of the stimulus pulses that evoked the corresponding ECAP.

[0092] Figure 2 This is a block diagram illustrating an example configuration of components of the IMD 200 according to one or more techniques disclosed herein. The IMD 200 can be... Figure 1 An example of IMD 110. In Figure 2 In the example shown, IMD 200 includes a stimulus generation circuit 202, a switching circuit 204, a sensing circuit 206, a communication circuit 208, a processing circuit 210, a storage device 212, multiple sensors 222, and a power supply 224.

[0093] exist Figure 2In the example shown, storage device 212 stores therapeutic stimulation program 214 and ECAP test stimulation program 216 in a separate memory or a separate area within storage device 212. Storage device 212 also stores a scroll buffer 218 and histogram data 220. Each stored therapeutic stimulation program in therapeutic stimulation program 214 defines values ​​for a set of electrical stimulation parameters (e.g., a set of stimulation parameters), such as the combination of stimulation electrodes, electrode polarity, current or voltage amplitude, pulse width, pulse rate, and pulse shape. Each stored ECAP test stimulation program 216 defines values ​​for a set of electrical stimulation parameters (e.g., a set of control stimulation parameters), such as the combination of stimulation electrodes, electrode polarity, current or voltage amplitude, pulse width, pulse rate, and pulse shape. ECAP test stimulation program 216 may also have additional information, such as instructions on when to deliver control pulses based on the pulse width and / or frequency of notification pulses defined in therapeutic stimulation program 214. In examples where control pulses are provided to the patient without notification pulses, a separate ECAP test stimulation program may not be necessary. Conversely, an ECAP test stimulation procedure for treatment that includes only control pulses can define the same control pulses as the corresponding treatment stimulation procedure that includes those control pulses.

[0094] Therefore, in some examples, the stimulation generation circuit 202 generates an electrical stimulation signal according to the described electrical stimulation parameters. Other ranges of stimulation parameter values ​​may also be used, depending on the target stimulation site within the patient 105. Although stimulation pulses are described, the stimulation signal can be of any form, such as a continuous-time signal (e.g., a sine wave). The switching circuit 204 may include one or more switch arrays, one or more multiplexers, one or more switches (e.g., a switch matrix or other set of switches), or other circuitry configured to direct stimulation signals from the stimulation generation circuit 202 to one or more of electrodes 232 and 234 or to direct sensing signals from one or more of electrodes 232 and 234 to sensing circuit 206. In other examples, the stimulation generation circuit 202 and / or sensing circuit 206 may include sensing circuitry that directs signals to and / or from one or more of electrodes 232 and 234, which may or may not include the switching circuit 204.

[0095] Sensing circuit 206 monitors signals from any combination of electrodes 232, 234. In some examples, sensing circuit 206 includes one or more amplifiers, filters, and analog-to-digital converters. Sensing circuit 206 can be used to sense physiological signals, such as ECAP. In some examples, sensing circuit 206 detects ECAP from a specific combination of electrodes 232, 234. In some cases, the specific combination of electrodes used to sense ECAP includes electrodes different from the set of electrodes 232, 234 used to deliver stimulation pulses. Alternatively, in other cases, the specific combination of electrodes used to sense ECAP includes at least one of the same set of electrodes used to deliver stimulation pulses to patient 105. Sensing circuit 206 can provide signals to analog-to-digital converters for conversion into digital signals for processing, analysis, storage, or output by processing circuit 210.

[0096] Under the control of the processing circuit 210, the communication circuit 208 supports communication between the IMD 200 and an external programmer. Figure 2 Wireless communication between the IMD 200 (not shown) or another computing device. The processing circuitry 210 of the IMD 200 can receive values ​​of various stimulation parameters (e.g., amplitude and electrode combinations) from an external programmer via the communication circuitry 208 as updates to the program. Updates to the therapeutic stimulation program 214 and the ECAP test stimulation program 216 can be stored in the storage device 212. The communication circuitry 208 in the IMD 200, as well as telemetry circuitry (e.g., external programmers) in other devices and systems described herein, can communicate via radio frequency (RF) communication technology. Additionally, the communication circuitry 208 can interact with an external medical device programmer (IMD 200) via proximity sensing interaction between the IMD 200 and the external programmer. Figure 2 (Not shown in the image) Communication. An external programmer can be... Figure 1 An example of an external programmer 150. Therefore, the communication circuit 208 can continuously, at periodic intervals, or upon request from the IMD 110 or the external programmer.

[0097] Processing circuitry 210 may include any one or more of the following: a microprocessor, a controller, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), discrete logic circuitry, or any other processing circuitry configured to provide functionality attributable to processing circuitry 210, which may be embodied herein as firmware, hardware, software, or any combination thereof. Processing circuitry 210 controls stimulation generation circuitry 202 to generate stimulation signals according to therapeutic stimulation program 214 and ECAP test stimulation program 216 stored in storage device 212, applying stimulation parameter values ​​specified by one or more programs, such as the amplitude, pulse width, pulse rate, and pulse shape of each stimulation signal.

[0098] exist Figure 2 In the example shown, the set of electrodes 232 includes electrodes 232A, 232B, 232C, and 232D, and the set of electrodes 234 includes electrodes 234A, 234B, 234C, and 234D. In other examples, a single lead may include all eight electrodes 232 and 234 along a single axial length of the lead. The processing circuit 210 also controls the stimulation generation circuit 202 to generate stimulation signals and apply them to selected combinations of electrodes 232, 234. In some examples, the stimulation generation circuit 202 includes switching circuitry (as an alternative to or complement to switching circuitry 204) that can couple stimulation signals to selected conductors within the lead 230, which in turn deliver stimulation signals across the selected electrodes 232, 234. Such switching circuitry may be a switch array, switch matrix, multiplexer, or configured to selectively couple stimulation energy to selected electrodes 232, 234 and selectively utilize the selected electrodes 232, 234 to sense bioelectric nerve signals in the patient's spinal cord. Figure 2 (not shown) any other type of switching circuit.

[0099] However, in other examples, the stimulus generation circuit 202 does not include a switching circuit, and the switching circuit 204 does not interface between the stimulus generation circuit 202 and the electrodes 232, 234. In these examples, the stimulus generation circuit 202 includes multiple pairs of voltage sources, current sources, voltage sinks, or current sinks connected to each electrode 232, 234, such that each pair of electrodes has a unique signal circuit. In other words, in these examples, each of the electrodes 232, 234 is independently controlled via its own signal circuit (e.g., via regulating a combination of voltage sources and sinks or regulating a combination of current sources and sinks), which is the opposite of the switching signal between the electrodes 232, 234.

[0100] The electrodes 232, 234 on the corresponding leads 230 can be constructed in various different designs. For example, one or two leads 230 may include one or more electrodes at each longitudinal location along the length of the lead, such as one electrode at each location A, B, C, D at different peripheral locations on the periphery of the lead. In one example, the electrodes may be electrically coupled to the stimulation generation circuit 202 via corresponding wires, for example, via a switching circuit 204 and / or a switching circuit of the stimulation generation circuit 202, which are straight or coiled within the housing of the lead and extend to a connector at the proximal end of the lead. In another example, each electrode on the lead may be an electrode disposed on a thin film. The thin film may include conductive traces of each electrode extending the length of the thin film to the proximal connector. The thin film may then be wrapped around an internal component (e.g., in a spiral shape) to form the lead 230. These and other configurations can be used to construct leads with complex electrode geometries.

[0101] Despite Figure 2 The sensing circuit 206 is embedded in a common housing together with the stimulus generation circuit 202 and the processing circuit 210. However, in other examples, the sensing circuit 206 may be in a different housing from the IMD 200 and may communicate with the processing circuit 210 via wired or wireless communication technology.

[0102] In some examples, one or more of electrodes 232 and 234 are used to sense the ECAP. For example, electrodes 232 and 234 can sense the voltage amplitude of a portion of the ECAP signal, wherein the sensed voltage amplitude is a characteristic of the ECAP signal.

[0103] Storage device 212 can be configured to store information within IMD 200 during operation. Storage device 212 may include a computer-readable storage medium or a computer-readable storage device. In some examples, storage device 212 includes one or more of short-term memory or long-term memory. Storage device 212 may include, for example, random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), ferroelectric random access memory (FRAM), magnetic disk, optical disk, flash memory, or electrically programmable memory (EPROM) or electrically erasable programmable memory (EEPROM). In some examples, storage device 212 is used to store data indicating instructions to be executed by processing circuitry 210. As discussed above, storage device 212 is configured to store therapeutic stimulation program 214 and ECAP test stimulation program 216.

[0104] In some examples, the stimulation generation circuit 202 may be configured to deliver electrical stimulation therapy to the patient 105. In some cases, the electrical stimulation therapy may include multiple notification pulses. Additionally, the stimulation generation circuit 202 may be configured to deliver multiple control pulses, wherein the multiple control pulses are interleaved with at least some of the notification pulses. The stimulation generation circuit may deliver the multiple notification pulses and multiple control pulses to a target tissue (e.g., spinal cord 120) of the patient 105 via electrodes 232, 234 of lead 230. By delivering such notification and control pulses, the stimulation generation circuit 202 may induce responsive ECAPs in the target tissue, which propagate through the target tissue and then return to electrodes 232, 234. In some examples, combinations of electrodes 232, 234 different from the combinations of electrodes 232, 234 delivering notification pulses and electrodes 232, 234 delivering control pulses may sense responsive ECAPs. Sensing circuit 206 may be configured to detect responsive ECAPs via electrodes 232, 234 and lead 230. In other examples, when the control pulses also provide a therapeutic effect to the patient, the stimulation generation circuit 202 can be configured to deliver multiple control pulses without delivering any notification pulses.

[0105] In some cases, processing circuitry 210 may instruct sensing circuitry 206 to continuously monitor ECAP. In other cases, processing circuitry 210 may instruct sensing circuitry 206 to monitor ECAP based on signals from sensors(s)222. For example, processing circuitry 210 may activate sensing circuitry 206 based on the patient 105's activity level exceeding an activity level threshold (e.g., the accelerometer signals from sensors(s)222 rise above the threshold). In some examples, activating and deactivating sensing circuitry 206 may extend the battery life of power supply 224.

[0106] In some examples, processing circuitry 210 determines whether a characteristic of the first ECAP is greater than a threshold ECAP characteristic value. The threshold ECAP characteristic value may be stored in storage device 212. In some examples, the characteristic of the first ECAP is the voltage amplitude of the first ECAP. In some such examples, the threshold ECAP characteristic value is selected from a range of approximately 10 microvolts (μV) to approximately 20 μV. In other examples, processing circuitry 210 determines whether another characteristic of the first ECAP (e.g., ECAP current amplitude, ECAP slew rate, area under the ECAP, ECAP slope, or ECAP duration) is greater than the threshold ECAP characteristic value.

[0107] If processing circuit 210 determines that the characteristic of the first ECAP is greater than a threshold ECAP characteristic value, processing circuit 210 is configured to activate a decrement mode, thereby changing at least one parameter of each treatment pulse in a set of notification pulses delivered by IMD 200 after sensing circuit 206 senses the first ECAP. Additionally, when decrement mode is activated, processing circuit 210 may change at least one parameter of each control pulse in a set of control pulses delivered by IMD 200 after sensing circuit 206 senses the first ECAP. In some examples, at least one parameter of the notification pulse and at least one parameter of the control pulse adjusted by processing circuit 210 during decrement mode includes the stimulation current amplitude. In some such examples, during decrement mode, processing circuit 210 reduces the current amplitude of each successive stimulation pulse (e.g., each treatment pulse and each control pulse) delivered by IMD 200. In other examples, at least one parameter of the stimulation pulse adjusted by processing circuit 210 during decrement mode includes any combination of current amplitude, voltage amplitude, slew rate, pulse shape, pulse frequency, or pulse duration.

[0108] exist Figure 2 In the example shown, the decrementing pattern is stored in storage device 212 as part of control strategy 213. The decrementing pattern may include a list of instructions that enable processing circuitry 210 to adjust the parameters of the stimulation pulses according to a function. In some examples, when the decrementing pattern is activated, processing circuitry 210 decreases the parameters (e.g., current) of each successive treatment pulse and each successive control pulse according to a linear function. In other examples, when the decrementing pattern is activated, processing circuitry 210 decreases the parameters (e.g., current) of each successive treatment pulse and each successive control pulse according to an exponential, logarithmic, or piecewise function. When the decrementing pattern is activated, sensing circuitry 206 may continue to monitor the responsiveness ECAP. Furthermore, sensing circuitry 206 may detect the ECAP in response to control pulses delivered by IMD 200.

[0109] Throughout the decrementing mode, the processing circuitry can monitor the ECAP in response to the stimulation pulse. The processing circuitry 210 can determine whether the characteristic of the second ECAP is less than a threshold ECAP characteristic value. In some cases, the second ECAP may be the first ECAP that is less than the threshold ECAP characteristic value after the first ECAP. In other words, each ECAP recorded by the sensing circuitry 206 between the first and second ECAP is greater than or equal to the threshold ECAP characteristic value. Based on the fact that the characteristic of the second ECAP is less than the threshold ECAP characteristic value, the processing circuitry 210 can deactivate the decrementing mode and activate the incrementing mode, thereby changing at least one parameter of each treatment pulse in a set of notification pulses delivered by the IMD 200 after the sensing circuitry 206 senses the second ECAP. Additionally, when the incrementing mode is activated, the processing circuitry 210 can change at least one parameter of each control pulse in a set of control pulses delivered by the IMD 200 after the sensing circuitry 206 senses the second ECAP.

[0110] In some examples, at least one parameter of the notification pulse and at least one parameter of the control pulse adjusted by the processing circuit 210 during the increment mode include the stimulation current amplitude. In some such examples, during the increment mode, the processing circuit 210 increases the current amplitude of each successive stimulation pulse (e.g., each treatment pulse and each control pulse) delivered by the IMD 200. In other examples, at least one parameter of the stimulation pulse adjusted by the processing circuit 210 during the increment mode includes any combination of current amplitude, voltage amplitude, slew rate, pulse shape, pulse frequency, or pulse duration.

[0111] exist Figure 2 In the example shown, the incrementing pattern is stored in storage device 212 as part of control strategy 213. The incrementing pattern may include a list of instructions that enable processing circuitry 210 to adjust the parameters of the stimulation pulses according to a function. In some examples, when the incrementing pattern is activated, processing circuitry 210 increases the parameters (e.g., current) of each successive treatment pulse and each successive control pulse according to a linear function. In other examples, when the incrementing pattern is activated, processing circuitry 210 increases the parameters (e.g., current) of each successive treatment pulse and each successive control pulse according to a non-linear function (such as an exponential, logarithmic, or piecewise function). When the incrementing pattern is activated, sensing circuitry 206 may continue to monitor the responsiveness ECAP. Furthermore, sensing circuitry 206 may detect the ECAP in response to control pulses delivered by IMD 200.

[0112] Processing circuit 210 can perform an incrementing mode, causing one or more parameters of the stimulation pulse to return to the baseline parameter values ​​of the stimulation pulse delivered before processing circuit 210 activates the decrementing mode (e.g., before sensing circuit 206 detects the first ECAP). By first decrementing and then incrementing the stimulation pulse in response to ECAP exceeding a threshold ECAP characteristic value, processing circuit 210 can prevent patient 105 from experiencing transient hyperstimulation or reduce the severity of transient hyperstimulation experienced by patient 105.

[0113] Although in some examples, sensing circuit 206 senses an ECAP occurring in response to a control pulse delivered according to ECAP test stimulation procedure 216, in other examples, sensing circuit 206 senses an ECAP occurring in response to a notification pulse delivered according to treatment stimulation procedure 214. The techniques disclosed herein enable IMD 200 to switch between decrement and increment modes using any combination of ECAPs corresponding to notification pulses and ECAPs corresponding to control pulses.

[0114] The multiple sensors 222 may include one or more sensing elements that sense values ​​of corresponding patient parameters. As described, electrodes 232 and 234 may be electrodes that sense characteristic values ​​of the ECAP. The multiple sensors 222 may include one or more accelerometers, optical sensors, chemical sensors, temperature sensors, pressure sensors, or any other type of sensor. The multiple sensors 222 may output patient parameter values ​​that can be used as feedback to control the delivery of treatment. For example, the multiple sensors 222 may indicate patient activity, and the processing circuitry 210 may increase the frequency of control pulses and ECAP sensing in response to detecting an increase in patient activity. In one example, the processing circuitry 210 may initiate control pulses and corresponding ECAP sensing in response to a signal from the multiple sensors 222 indicating that patient activity has exceeded an activity threshold. Conversely, the processing circuitry 210 may decrease the frequency of control pulses and ECAP sensing in response to detecting a decrease in patient activity. For example, in response to the multiple sensors 222 no longer indicating that the sensed patient activity exceeds a threshold, the processing circuitry 210 may pause or stop the delivery of control pulses and ECAP sensing. In this way, processing circuitry 210 can dynamically deliver control pulses and sense ECAP signals based on patient activity to reduce system power consumption when the distance between the electrode and neuron is unlikely to change and to increase system responsiveness to ECAP changes when the distance between the electrode and neuron is likely to change. IMD 200 may include additional sensors that are housed within the IMD 200 housing and / or coupled via lead 130 or one of other leads. Additionally, IMD 200 may wirelessly receive sensor signals from remote sensors, for example, via communication circuitry 208. In some examples, one or more of these remote sensors may be located outside the patient's body (e.g., carried on the skin surface, attached to clothing, or otherwise positioned outside the patient 105). In some examples, signals from sensor(s)(s)222 indicate location or body state (e.g., asleep, awake, sitting, standing, etc.), and processing circuitry 210 can select a target ECAP characteristic value based on the indicated location or body state.

[0115] Power source 224 is configured to deliver operating power to components of IMD 200. Power source 224 may include a battery and power generation circuitry to generate operating power. In some examples, the battery is rechargeable to allow for extended operation. In some examples, charging is accomplished through proximity-inductive interaction between an external charger and an inductive charging coil within IMD 200. Power source 224 may include any one or more of a variety of battery types, such as nickel-cadmium batteries and lithium-ion batteries.

[0116] Figure 3This is a block diagram illustrating an example configuration of components of an external programmer 300 according to one or more techniques disclosed herein. The external programmer 300 may be... Figure 1 An example of an external programmer 150. Although the external programmer 300 is generally described as a handheld device, it can be a larger portable device or a more stationary device. Additionally, in other examples, the external programmer 300 may be included as part of an external charging device, or may include the functionality of an external charging device. Figure 3 As shown, the external programmer 300 may include processing circuitry 352, storage device 354, user interface 356, communication circuitry 358, and power supply 360. Storage device 354 may store instructions that, when executed by processing circuitry 352, enable processing circuitry 352 and external programmer 300 to provide the functions attributed to external programmer 300 in this disclosure. Each of these components, circuits, or modules may include circuitry configured to perform some or all of the functions described herein. For example, processing circuitry 352 may include processing circuitry configured to perform the processes discussed with respect to processing circuitry 352.

[0117] Generally, the external programmer 300 includes any suitable hardware arrangement, either individually or in combination with software and / or firmware, to perform techniques attributable to the external programmer 300 and its processing circuitry 352, user interface 356, and communication circuitry 358. In various examples, the external programmer 300 may include one or more processors, such as one or more microprocessors, DSPs, ASICs, FPGAs, or any other equivalent integrated or discrete logic circuitry, and any combination of such components. In various examples, the external programmer 300 may also include a storage device 354, such as RAM, ROM, PROM, EPROM, EEPROM, flash memory, hard disk, CD-ROM, containing executable instructions to cause one or more processors to perform actions attributable to those processors. Additionally, while the processing circuitry 352 and communication circuitry 358 are described as separate modules, in some examples, they are functionally integrated. In some examples, the processing circuitry 352 and communication circuitry 358 correspond to separate hardware units, such as ASICs, DSPs, FPGAs, or other hardware units.

[0118] Storage device 354 (e.g., a storage device) may store instructions that, when executed by processing circuitry 352, cause processing circuitry 352 and external programmer 300 to provide the functions attributed to external programmer 300 in this disclosure. For example, storage device 354 may include instructions instructing processing circuitry 352 to retrieve a parameter set from memory, select a spatial electrode movement mode, or receive user input and send a corresponding command to IMD 200, or instructions for any other function. Additionally, storage device 354 may include multiple programs, each including a parameter set defining stimulation pulses (e.g., control pulses and / or notification pulses). Storage device 354 may also store data received from a medical device (e.g., IMD 110). For example, storage device 354 may store ECAP-related data recorded at the sensing module of the medical device, and storage device 354 may also store data from one or more sensors of the medical device.

[0119] User interface 356 may include buttons or a keyboard, lights, a voice command speaker, a display (such as a liquid crystal display (LCD)), a light-emitting diode (LED), or an organic light-emitting diode (OLED). In some examples, the display includes a touchscreen. User interface 356 may be configured to display any information related to the delivery of electrical stimulation, identified patient behaviors, sensed patient parameter values, patient behavior criteria, or any other such information. User interface 356 may also receive user input via user interface 356. Input may, for example, be in the form of pressing a button on a keypad or selecting an icon from a touchscreen. Input may request to start or stop electrical stimulation, input may request a new spatial electrode movement pattern or a change to an existing spatial electrode movement pattern, input may request some other change to the delivery of electrical stimulation. In some examples, user interface 356 may display one or more requests from a patient guidance wizard executed by a system including an external programmer 300 and / or an IMD 110, and user interface 356 may receive one or more user responses to one or more requests.

[0120] Communication circuitry 358, under the control of processing circuitry 352, can support wireless communication between the medical device and external programmer 300. Communication circuitry 358 can also be configured to communicate with another computing device via wireless communication technology or directly via a wired connection. In some examples, communication circuitry 358 provides wireless communication via RF or proximity sensing media. In some examples, communication circuitry 358 includes an antenna, which can take various forms, such as internal or external antennas.

[0121] Examples of local wireless communication technologies that can be used to facilitate communication between the external programmer 300 and the IMD 110 include RF communication conforming to the following standards: 802.11 standard, or Specification sets, or other standards or proprietary telemetry protocols. In this way, other external devices may be able to communicate with the external programmer 300 without establishing a secure wireless connection. As described herein, the communication circuitry 358 can be configured to transmit spatial electrode movement patterns or other stimulation parameter values ​​to the IMD 110 for the delivery of electrical stimulation therapy.

[0122] In some examples, the selection of stimulation parameters or therapeutic stimulation procedures is transmitted to a medical device for delivery to the patient (e.g., Figure 1 (Patient 105). In other examples, treatment may include medications, activities, or other instructions that patient 105 must perform themselves or that a caregiver performs for patient 105. In some examples, the external programmer 300 provides visual, auditory, and / or tactile notifications indicating that a new instruction has been given. In some examples, the external programmer 300 requires user input confirming that the instruction has been completed.

[0123] According to the technology disclosed herein, the user interface 356 of the external programmer 300 receives instructions from a clinician to instruct the processor of the medical device to update one or more therapeutic stimulation programs or to update one or more ECAP test stimulation programs. Updating the therapeutic stimulation program and the ECAP test stimulation program may include changing one or more parameters of the stimulation pulses delivered by the medical device according to the program, such as the amplitude, pulse width, frequency, and pulse shape of the notification and / or control pulses. The user interface 356 may also receive instructions from the clinician to command any electrical stimulation, including the start or stop of the control and / or notification pulses.

[0124] Power supply 360 is configured to deliver operating power to components of external programmer 300. Power supply 360 may include a battery and power generation circuitry to generate operating power. In some examples, the battery is rechargeable to allow for extended operation. Charging can be achieved by electrically coupling power supply 360 to a bracket or plug connected to an AC outlet. Alternatively, charging can be achieved through proximity-induced interaction between an external charger and an inductive charging coil within external programmer 300. In other examples, conventional batteries (e.g., nickel-cadmium batteries or lithium-ion batteries) can be used. Additionally, external programmer 300 may be directly coupled to an AC outlet for operation.

[0125] Figure 3 The architecture of the external programmer 300 shown in the illustration is for illustrative purposes only. The technologies described in this disclosure can be used in… Figure 3 The example external programmer 300 is implemented, but it can also be implemented in other types of systems not specifically described herein. Nothing in this disclosure should be construed as limiting these techniques to... Figure 3 The example architecture shown.

[0126] Figure 4 This is an example evoked compound action potential (ECAP) curve 402 for sensing a corresponding stimulus impulse according to one or more techniques of this disclosure. Figure 4 As shown, graph 402 illustrates example ECAP signals 404 (dashed line) and 406 (solid line). In some examples, each of ECAP signals 404 and 406 is sensed from a control pulse delivered from the protective cathode, wherein the control pulse is a biphase pulse comprising the phase-to-phase interval between each positive and negative phase of the pulse. In some such examples, the protective cathode comprises an 8-electrode lead (e.g., ...). Figure 1 The stimulation electrode is located at the end of lead 130, while two sensing electrodes are provided at the other end of the 8-electrode lead. The ECAP signal 404 represents the sensed voltage amplitude as a result of a sub-detection threshold stimulation pulse or a stimulation pulse that results in an undetectable ECAP. A peak 408 is detected in the ECAP signal 404, and this peak represents an artifact of the delivered control pulse. However, no propagating signal is detected after the artifact in the ECAP signal 404 because the control pulse is a sub-detection threshold stimulation pulse.

[0127] In contrast to ECAP signal 404, ECAP signal 406 represents the voltage amplitude detected from the supra-detection stimulation threshold control pulse. A peak 408 is detected in ECAP signal 406, and this peak represents an artifact of the delivered control pulse. Following peak 408, ECAP signal 406 also includes peaks P1, N1, and P2, which are three typical peaks representing the propagating action potential from ECAP. The artifact and peaks P1, N1, and P2 typically last for approximately 1 millisecond (ms). Different characteristics can be identified when ECAP is detected in ECAP signal 406. For example, the characteristic of ECAP might be the amplitude between N1 and P2. Even if the artifact affects the relatively large signal P1, the N1-P2 amplitude can be easily detected, and the N1-P2 amplitude is likely to be minimally affected by electron drift in the signal. In other examples, the characteristic of ECAP used to control subsequent control pulses and / or notification pulses could be the amplitude of P1, N1, or P2 relative to a neutral or zero voltage. In some examples, the characteristic of the ECAP used to control subsequent control or notification pulses is the sum of two or more of the peaks P1, N1, or P2. In other examples, the characteristic of the ECAP signal 406 may be the area under one or more of the peaks P1, N1, and / or P2. In other examples, the characteristic of the ECAP may be the ratio of one of the peaks P1, N1, or P2 to another of these peaks. In some examples, the characteristic of the ECAP is the slope between two points in the ECAP signal, such as the slope between N1 and P2. In other examples, the characteristic of the ECAP may be the time between two points in the ECAP, such as the time between N1 and P2. The time between the delivery of the stimulation pulse and the point in the ECAP signal may be referred to as the latency of the ECAP and may indicate the type of fiber captured by the stimulation pulse (e.g., control pulse). An ECAP signal with a lower latency (i.e., a smaller latency value) indicates a higher percentage of nerve fibers with a higher signal propagation speed, while an ECAP signal with a higher latency (i.e., a larger latency value) indicates a higher percentage of nerve fibers with a slower signal propagation speed. Latency can also refer to the time between detecting an electrical feature at one electrode and then detecting it again at a different electrode. This time, or latency, is inversely proportional to the conduction velocity of the nerve fiber. Other characteristics of the ECAP signal can be used in other examples.

[0128] As long as the pulse amplitude is greater than a threshold, thereby depolarizing the nerve and propagating the signal, the amplitude of the ECAP signal increases with the increase of the control pulse amplitude. When the notification pulse is determined to deliver effective treatment to the patient 105, the target ECAP characteristic (e.g., target ECAP amplitude) can be determined based on the ECAP signal detected from the control pulse. Therefore, the ECAP signal represents the distance between the stimulating electrode and the nerve, which is suitable for the stimulation parameter value of the notification pulse being delivered at that time. Therefore, the IMD110 can attempt to use the detected changes in the measured ECAP characteristic value to change the treatment pulse parameter value and maintain the target ECAP characteristic value during treatment pulse delivery.

[0129] Figure 5A A timing diagram 500A illustrates an example of an electrical stimulation pulse, a corresponding stimulation signal, and a corresponding sensed ECAP, according to one or more techniques disclosed herein. For convenience, refer to... Figure 2 IMD 200 description Figure 5A As shown in the figure, timing diagram 500A includes a first channel 502, multiple stimulation pulses 504A-504N (collectively referred to as "stimulation pulses 504"), a second channel 506, multiple corresponding ECAPs 508A-508N (collectively referred to as "ECAPs 508"), and multiple stimulation signals 509A-509N (collectively referred to as "stimulation signals 509"). In some examples, stimulation pulse 504 may represent a control pulse configured to elicit ECAPs 508 that can be detected by IMD 200, but this is not necessary. Stimulation pulse 504 can represent any type of pulse that can be delivered by IMD 200. Figure 5A In the example, the IMD 200 can deliver treatment using a control pulse instead of a notification pulse or without using a notification pulse.

[0130] The first channel 502 is a time / voltage (and / or current) graph indicating the voltage (or current) of at least one of the electrodes 232, 234. In one example, the stimulating electrode of the first channel 502 may be located on the side of the lead opposite to the sensing electrode of the second channel 506. The stimulation pulse 504 may be an electrical pulse delivered to the patient's spinal cord by at least one of the electrodes 232, 234, and the stimulation pulse 504 may be a balanced biphasic square wave pulse with phase intervals. In other words, each stimulation pulse 504 is shown as having a negative phase and a positive phase separated by phase intervals. For example, the duration and amplitude of the negative voltage of the stimulation pulse 504 may be the same as its positive voltage. Note that the negative voltage phase may precede or follow the positive voltage phase. The stimulation pulse 504 may be delivered according to a test stimulation program 216 stored in the storage device 212 of the IMD 200, and the test stimulation program 216 may be updated according to user input via an external programmer and / or according to signals from sensors(s)222. In one example, the stimulation pulse 504 may have a pulse width of less than approximately 300 microseconds (e.g., the total time of the positive phase, negative phase, and phase interval is less than 300 microseconds). In another example, for each phase of the biphasic pulse, the stimulation pulse 504 may have a pulse width of approximately 100 μs. Figure 5A As shown, the stimulation pulse 504 can be delivered via channel 502. The delivery of the stimulation pulse 504 can be achieved by lead 230 in the form of a protective cathode electrode assembly. For example, if lead 230 is a linear 8-electrode lead, the protective cathode assembly consists of a central cathode electrode and an anode electrode adjacent to the cathode electrode.

[0131] The second channel 506 is a time / voltage (and / or current) graph indicating the voltage (or current) of at least one of the electrodes 232, 234. In one example, the electrode of the second channel 506 may be located on the side of the lead opposite to the electrode of the first channel 502. In response to the stimulation pulse 504, an ECAP 508 can be sensed from the patient's spinal cord at electrodes 232, 234. The ECAP 508 is an electrical signal that can propagate along the nerve away from the origin of the stimulation pulse 504. In one example, the ECAP 508 is sensed by an electrode different from the electrode used to deliver the stimulation pulse 504. Figure 5A As shown, ECAP 508 can be recorded on the second channel 506.

[0132] Stimulus signals 509A, 509B, and 509N can be sensed by lead 230 and sensing circuit 206, and can be sensed during the same time period as the delivery of stimulation pulse 504. Because the stimulation signals may have a larger amplitude and intensity than ECAP 508, any ECAP arriving at IMD 200 during the occurrence of stimulation signal 509 may not be sufficiently sensed by sensing circuit 206 of IMD 200. However, because at least a portion of each ECAP 508, or an ECAP 508 used as feedback for stimulation pulse 504, decreases after each stimulation pulse 504, ECAP 508 can be sufficiently sensed by sensing circuit 206. Figure 5A As shown, stimulation signals 509 and ECAP 508 can be recorded on channel 506. In some examples, ECAP 508 may not follow the corresponding stimulation signal 509 when ECAP is not triggered by stimulation pulse 504 or when the amplitude of ECAP is too low (e.g., below the detection threshold) to be detected.

[0133] Figure 5B This is a timing diagram 500B illustrating an example of an electrical stimulation pulse, a corresponding stimulation signal, and a corresponding sensed ECAP, according to one or more techniques of this disclosure. For convenience, refer to... Figure 2 IMD 200 description Figure 5B As shown in the figure, the timing diagram 500B includes a first channel 510, multiple control pulses 512A-512N (collectively referred to as "control pulses 512"), a second channel 520, multiple notification pulses 524A-524N (collectively referred to as "notification pulses 524") including passive charging phases 526A-526N (collectively referred to as "passive charging phases 526"), a third channel 530, multiple corresponding ECAPs 536A-536N (collectively referred to as "ECAPs 536") and multiple stimulation signals 538A-538N (collectively referred to as "stimulation signals 538").

[0134] The first channel 510 is a time / voltage (and / or current) graph indicating the voltage (or current) of at least one of the electrodes 232, 234. In one example, the stimulating electrode of the first channel 510 may be located on the side of the lead opposite to the sensing electrode of the third channel 530. The control pulse 512 may be an electrical pulse delivered to the patient's spinal cord by at least one of the electrodes 232, 234, and the control pulse 512 may be a balanced biphasic square wave pulse with phase intervals. In other words, each control pulse 512 is shown as having a negative phase and a positive phase separated by phase intervals. For example, the duration of the negative voltage of the control pulse 512 may be the same as its positive voltage. Note that the negative voltage phase may precede or follow the positive voltage phase. The control pulse 512 may be delivered according to a test stimulation program 216 stored in the storage device 212 of the IMD 200, and the test stimulation program 216 may be updated according to user input via an external programmer and / or according to signals from sensors(s)222. In one example, the control pulse 512 can have a pulse width of 300 microseconds (e.g., the total time for the positive phase, negative phase, and phase-to-phase interval is 300 microseconds). In another example, for each phase of the biphase pulse, the control pulse 512 can have a pulse width of approximately 100 μs. Figure 5B As shown, control pulse 512 can be delivered via first channel 510. The delivery of control pulse 512 can be achieved by lead 230 in the form of a protective cathode electrode assembly. For example, if lead 230 is a linear 8-electrode lead, the protective cathode assembly consists of a central cathode electrode and an anode electrode immediately adjacent to the cathode electrode.

[0135] The second channel 520 is a time / voltage (and / or current) graph indicating the voltage (or current) of at least one of the electrodes 232, 234 used for the notification pulse. In one example, the electrodes of the second channel 520 may partially or completely share a common electrode with the electrodes of the first channel 510 and the third channel 530. The notification pulse 524 may also be delivered by the same lead 230 configured to deliver the control pulse 512. The notification pulse 524 may be interleaved with the control pulse 512 such that the two types of pulses are not delivered during overlapping time periods. However, the notification pulse 524 may or may not be delivered by the same electrode that delivers the control pulse 512. The notification pulse 524 may be a single-phase pulse with a pulse width greater than about 300 μs and less than about 1000 μs. In fact, the notification pulse 524 may be configured to have a longer pulse width than the control pulse 512. Figure 5B As shown, notification pulse 524 can be delivered on the second channel 520.

[0136] Notification pulse 524 can be configured for passive charging. For example, each notification pulse 524 can be followed by a passive charging phase 526 to equalize the charge on the stimulating electrodes. Unlike pulses configured for active charging, where any remaining charge on the tissue after the stimulation pulse is immediately removed from the tissue by an oppositely applied charge, passive charging allows the tissue to discharge naturally to a reference voltage (e.g., ground or rail voltage) after the treatment pulse terminates. In some examples, the electrodes of the medical device can be grounded at the medical device body. In this case, after notification pulse 524 terminates, the charge on the tissue surrounding the electrodes can dissipate to the medical device, resulting in a rapid decay of the remaining charge on the tissue after the pulse terminates. This rapid decay is demonstrated in passive charging phase 526. Passive charging phase 526 can have a duration in addition to the pulse width of the preceding notification pulse 524. In other examples ( Figure 5B (Not depicted in the text), the notification pulse 524 can be a biphase pulse with positive and negative phases (and in some examples, with phase-to-phase intervals between each phase), which can be referred to as a pulse that includes active charging. The notification pulse as a biphase pulse may or may not have a subsequent passive charging phase.

[0137] The third channel 530 is a time / voltage (and / or current) graph indicating the voltage (or current) of at least one of the electrodes 232, 234. In one example, the electrode of the third channel 530 may be located on the side of the lead opposite to the electrode of the first channel 510. In response to the control pulse 512, an ECAP 536 can be sensed from the patient's spinal cord at electrodes 232, 234. The ECAP 536 is an electrical signal that can propagate along the nerve away from the origin of the control pulse 512. In one example, the ECAP 536 is sensed by an electrode different from the electrode used to deliver the control pulse 512. Figure 5B As shown, ECAP 536 can be recorded on the third channel 530.

[0138] Stimulus signals 538A, 538B, and 538N can be sensed by lead 230 and can be sensed during the same time period as the delivery of control pulse 512 and notification pulse 524. Because the stimulation signals may have a larger amplitude and intensity than ECAP 536, any ECAP arriving at IMD 200 during the occurrence of stimulation signal 538 may not be sufficiently sensed by sensing circuitry 206 of IMD 200. However, because each ECAP 536 decreases after each control pulse 512 completes and before the delivery of the next notification pulse 524, ECAP 536 can be sufficiently sensed by sensing circuitry 206. Figure 5B As shown, stimulation signals 538 and ECAP 536 can be recorded on channel 530.

[0139] Figure 6A A timing diagram 600A illustrates an example of an electrical stimulation pulse, a corresponding stimulation signal, and a corresponding sensed ECAP, according to one or more techniques of this disclosure. For convenience, refer to... Figure 2 IMD 200 description Figure 6A As shown in the figure, timing diagram 600A includes a first channel 602, multiple stimulation pulses 604A-604N (collectively referred to as "stimulation pulses 604"), a second channel 606, multiple corresponding ECAPs 608A-608N (collectively referred to as "ECAP 608"), and multiple stimulation signals 609A-609N (collectively referred to as "stimulation signals 609"). In some examples, stimulation pulse 604 may represent a control pulse configured to elicit ECAP 608 that can be detected by IMD 200, but this is not necessary. Stimulation pulse 604 can represent any type of pulse that can be delivered by IMD 200. Figure 6A In the example, the IMD 200 can deliver treatment using a control pulse instead of a notification pulse or without using a notification pulse.

[0140] Figure 6A The timing diagram 600A can be used with Figure 5A The timing diagram 500A is basically the same, the difference being that stimulation pulses 604A and 604N did not induce ECAPs detectable by the IMD 200. Although stimulation pulse 604B emitted ECAP 608B detectable by the IMD 200, Figure 6A In some examples, there may be situations where the IMD 200 does not sense enough detectable ECAP for treatment determination. In such cases, the IMD 200 can determine one or more characteristics of the stimulation signal 609 to determine one or more parameters of the upcoming stimulation pulse following the stimulation pulse 604N. For example, the IMD 200 can determine the amplitude of at least a portion of each stimulation signal of the stimulation signal 609 and determine one or more parameters of the upcoming stimulation pulse based on the determined amplitude. Although the stimulation signal 609 is shown as a square pulse, in some examples, the stimulation signal 609 may include other shapes and / or waveforms. In some examples, each stimulation signal in the stimulation signal 509 may include two or more phases. The processing circuitry 210 of the IMD 200 can analyze two or more phases of the stimulation signal 509 to determine the treatment.

[0141] Figure 6B This is a timing diagram 600B illustrating another example of an electrical stimulation pulse, a corresponding stimulation signal, and a corresponding sensed ECAP, based on one or more techniques of this disclosure. For convenience, refer to... Figure 2 IMD 200 description Figure 6BAs shown in the figure, timing diagram 600B includes a first channel 610, multiple control pulses 612A-612N (collectively referred to as "control pulses 612"), a second channel 620, multiple notification pulses 624A-624N (collectively referred to as "notification pulses 624") including passive charging phases 626A-626N (collectively referred to as "passive charging phases 626"), a third channel 630, multiple corresponding ECAPs 636A-636N (collectively referred to as "ECAP 636") and multiple stimulation signals 638A-638N (collectively referred to as "stimulation signals 638").

[0142] Figure 6B The timing diagram 600B can be used with Figure 5B The timing diagram 500B is basically the same, the difference being that control pulses 612A and 612N do not induce ECAP that can be detected by IMD 200. Although control pulse 612B emits ECAP 636B that can be detected by IMD 200, Figure 6B In some examples, there may be situations where the IMD 200 does not sense enough detectable ECAP for treatment determination. In such cases, the IMD 200 can determine one or more characteristics of the stimulation signal 638 to determine one or more parameters of the upcoming stimulation pulse following the control pulse 612N. For example, the IMD 200 can determine the amplitude of at least a portion of each stimulation signal of the stimulation signal 638 and determine one or more parameters of the upcoming stimulation pulse based on the determined amplitude. Although the stimulation signal 638 is shown as a square pulse, in some examples, the stimulation signal 639 may include other shapes and / or waveforms. In some examples, each stimulation signal in the stimulation signal 638 may include two or more phases. The processing circuitry 210 of the IMD 200 can analyze two or more phases of the stimulation signal 638 to determine the treatment.

[0143] Figure 7 A timing diagram 700 illustrating another example of an electrical stimulation pulse, a corresponding stimulation signal, and a corresponding ECAP, according to one or more techniques of this disclosure. For convenience, refer to... Figure 2 IMD200 description Figure 7 As shown in the figure, the timing diagram 700 includes a first channel 710, multiple control pulses 712A-712N (collectively referred to as "control pulses 712"), a second channel 720, multiple notification pulses 724A-724B (collectively referred to as "notification pulses 724") including passive charging phases 726A-726B (collectively referred to as "passive charging phases 726"), a third channel 730, multiple corresponding ECAPs 736A-736N (collectively referred to as "ECAP 736"), and multiple stimulus interference signals 738A-738N (collectively referred to as "stimulus interference signals 738"). Figure 7 It can be basically similar to Figure 5B Apart from the differences detailed below.

[0144] Two or more control pulses 712 may be delivered during each of the multiple time events (e.g., a window), and each time event represents the time between two consecutive notification pulses 724. For example, during each time event, a first control pulse may be immediately followed by a first corresponding ECAP, and after the first corresponding ECAP completes, a second control pulse may be immediately followed by a second corresponding ECAP. A notification pulse may begin after the second corresponding ECAP. In other examples not shown here, three or more control pulses 712 may be delivered during each of the multiple time events, and corresponding ECAP signals may be sensed.

[0145] Figure 8 A timing diagram 800 illustrating another example of an electrical stimulation pulse, a corresponding stimulation signal, and a corresponding ECAP, according to one or more techniques of this disclosure. For convenience, refer to... Figure 2 IMD200 description Figure 8 As shown in the figure, the timing diagram 800 includes a first channel 810, multiple control pulses 812A-812N (collectively referred to as "control pulses 812"), a second channel 820, multiple notification pulses 824A-824B (collectively referred to as "notification pulses 824") including passive charging phases 826A-826B (collectively referred to as "passive charging phases 826"), a third channel 830, a corresponding ECAP 836B (collectively referred to as "ECAP 836"), and multiple stimulus interference signals 838A-838N (collectively referred to as "stimulus interference signals 838"). Figure 8 The timing diagram 800 can be compared with Figure 7 The timing diagram 700 is basically the same, the difference being that control pulses 812A and 812N do not induce ECAP that can be detected by IMD 200. Although control pulse 812B emits ECAP 836B that can be detected by IMD 200, Figure 8 In the example, there may be a situation where IMD 200 does not sense enough detectable ECAP for treatment determination. In this case, IMD 200 can determine one or more characteristics of the stimulation signal 838 in order to determine one or more parameters of the upcoming stimulation pulse following the control pulse 812N.

[0146] Figure 9 The flowchart illustrates an example operation of controlling stimuli based on one or more sensed ECAPs, according to one or more techniques disclosed herein. For convenience, refer to... Figure 2 IMD200 description Figure 9.However, Figure 9 The technology can be performed by different components of the IMD 200 or by additional or alternative medical devices.

[0147] The stimulation generation circuit 202 of the IMD 200 can deliver electrical stimulation therapy to a patient (e.g., patient 105). To control the electrical stimulation therapy, the processing circuit 210 can guide the delivery of at least some stimulation pulses according to a treatment stimulation program 214 stored in the storage device 212, wherein the electrical stimulation therapy may include multiple control pulses and / or notification pulses. In some cases, the notification pulses may generate an ECAP that can be detected by the IMD 200. However, in other cases, the polarization of the notification pulses may interfere with the sensing of the ECAP in response to the notification pulses. In some examples, to induce an ECAP that can be detected by the IMD 200, the stimulation generation circuit 202 delivers multiple control pulses, which are interleaved with at least some of the notification pulses. The processing circuit 210 can control the delivery of the control pulses according to an ECAP testing stimulation program 216. Because the control pulses can be interleaved with the notification pulses, the sensing circuit 206 of the IMD 200 can detect multiple ECAPs. The sensing circuit 206 is configured to detect each of the multiple ECAPs after one of the control pulses and before a subsequent notification pulse of the multiple notification pulses. In this way, the IMD 200 can induce multiple ECAPs in the target tissue by delivering control pulses, without the notification pulses interfering with the IMD 200's sensing of the ECAPs.

[0148] like Figure 9 As shown, processing circuit 210 instructs stimulation generation circuit 202 to deliver control pulses (902). Stimulation generation circuit 202 can deliver control pulses to target tissue of patient 105 via any combination of electrodes 232, 234 of lead 230. In some examples, the control pulse may include a balanced biphasic square wave pulse employing an active charging phase. However, in other examples, the control pulse may include a monophasic pulse followed by a passive charging phase. In other examples, the control pulse may include an unbalanced biphasic portion and a passive charging portion. Although not required, the biphasic control pulse may include an interphase interval between the positive and negative phases to facilitate nerve impulse propagation in response to the first phase of the biphasic pulse. The control pulse may have a pulse width of 300 μs, such as a biphasic pulse with a duration of approximately 100 μs per phase.

[0149] After the delivery of the control pulse, the IMD 200 attempts to detect the ECAP (904). For example, the sensing circuit 206 may monitor signals from any combination of electrodes 232, 234 of the lead 230. In some examples, the sensing circuit 206 detects the ECAP from a specific combination of electrodes 232, 234. In some cases, the specific combination of electrodes used to sense the ECAP includes electrodes different from the set of electrodes 232, 234 used to deliver the stimulation pulse. Alternatively, in other cases, the specific combination of electrodes used to sense the ECAP includes at least one of the same set of electrodes used to deliver the stimulation pulse to the patient 105. In some examples, the specific combination of electrodes used to sense the ECAP may be located on the opposite side of the lead 230 to the specific combination of electrodes used to deliver the stimulation pulse. The IMD 200 may detect the ECAP in response to the control pulse. The IMD 200 may measure one or more characteristics of the responsive ECAP, such as ECAP amplitude, ECAP duration, peak-to-peak duration, or any combination thereof. For example, to measure the magnitude of ECAP, the IMD 200 can determine the voltage difference between the peak value of N1 ECAP and the peak value of P2 ECAP.

[0150] At block 906, processing circuitry 210 determines whether the ECAP amplitude of the responsive ECAP is greater than an ECAP amplitude threshold. If the ECAP amplitude is greater than the ECAP amplitude threshold (the "Yes" branch of block 906), processing circuitry 210 activates / continues the decrementing mode in IMD 200 (908). For example, if the decrementing mode is already "on" in IMD 200 when processing circuitry determines that the ECAP amplitude is greater than the ECAP amplitude threshold, processing circuitry 210 keeps IMD 200 in the decrementing mode. If the decrementing mode is "off" in IMD 200 when processing circuitry determines that the ECAP amplitude is greater than the ECAP amplitude threshold, processing circuitry 210 activates the decrementing mode. In some examples, the decrementing mode may be stored in storage device 212 as part of control strategy 213. The decrementing mode may be a set of instructions that cause IMD 200 to decrease one or more parameter values ​​for each successive notification pulse from a corresponding predetermined value (e.g., a value determined by the stimulus program) and to decrease one or more parameter values ​​for each successive control pulse from a corresponding predetermined value (e.g., a value determined by the stimulus program). In other words, the parameter value can be reduced from the value used by IMD 200 to define the corresponding pulse, provided that the ECAP amplitude does not exceed the threshold ECAP amplitude. For example, when the decrement mode is activated, processing circuitry 210 can reduce the current amplitude of each consecutive notification pulse delivered by IMD 200 and reduce the current amplitude of each consecutive control pulse delivered by IMD 200. After processing circuitry 210 activates / continues the decrement mode, the example operation can return to block 902, and IMD 200 can deliver another control pulse.

[0151] If the ECAP amplitude is not greater than the ECAP amplitude threshold (the "No" branch of box 906), then processing circuitry 210 determines whether a decrementing mode is activated in IMD 200 (910). If a decrementing mode is activated in IMD 200 (the "Yes" branch of box 910), then processing circuitry 210 deactivates the decrementing mode and activates an incrementing mode in IMD 200 (912). In some examples, the incrementing mode may be stored in storage device 212 as part of control strategy 213. An incrementing mode may be a set of instructions that cause IMD 200 to increment one or more parameter values ​​for each consecutive notification pulse and one or more parameter values ​​for each consecutive control pulse. For example, when the incrementing mode is activated, processing circuitry 210 may increase the current amplitude of each consecutive notification pulse delivered by IMD 200 and increase the current amplitude of each consecutive control pulse delivered by IMD 200. After the processing circuit 210 disables the decrement mode and activates the increment mode, the example operation can return to box 902 and IMD 200 can deliver another control pulse.

[0152] when Figure 9When the example operation reaches box 910 and the decrementing mode is not activated in IMD 200 (the "No" branch of box 910), processing circuitry 210 determines whether an incrementing mode is activated in IMD 200 (914). If the incrementing mode is activated in IMD 200 (the "Yes" branch of box 914), processing circuitry 210 can complete the incrementing mode in IMD 200 (916). In some examples, to complete the incrementing mode, processing circuitry 210 may increase the current amplitude of each successive notification pulse delivered by IMD 200 and increase the current amplitude of each successive control pulse delivered by IMD 200 until the pulse amplitude of the stimulation pulse reaches the current amplitude of the stimulation pulse delivered by IMD 200 before the decrementing mode was activated (e.g., a predetermined value that may be set by the stimulation program selected for treatment). In this way, the process may not be referred to as a fully closed-loop system. In other words, IMD 200 can monitor the high end (ECAP amplitude threshold) to adjust the stimulation pulse, without monitoring any low end of the sensed ECAP amplitude. For example, IMD 200 can continue to increase the current amplitude of successive notification pulses without any feedback from the sensed ECAP, unless the sensed ECAP value exceeds the ECAP amplitude threshold again. After processing circuitry 210 completes the incrementing mode, the example operation can return to block 902, and IMD 200 can deliver another control pulse. When Figure 9 When the example operation reaches box 914 and the incremental mode is not activated in IMD 200 (the "No" branch of box 914), the processing circuit 210 holds the stimulus (918) in IMD 200. Although Figure 9 The description covers both notification and control pulses, but it also addresses situations where the IMD200 only delivers control pulses to the patient (e.g., no notification pulses) for treatment. Figure 9 The technology is also applicable.

[0153] Figure 10 According to one or more techniques disclosed herein, a voltage / current / time graph 1000 is shown, which plots the control pulse current amplitude 1002, the notification pulse current amplitude 1004, the ECAP voltage amplitude 1008, and the second ECAP voltage amplitude 1010 as a function of time. Additionally, Figure 10 The threshold ECAP amplitude of 1006 is shown. For convenience, please refer to... Figure 2 IMD 200 description Figure 10 .However, Figure 10 The technology can be performed by different components of the IMD 200 or by additional or alternative medical devices.

[0154] Voltage / current / time plot 1000 illustrates the relationship between the sensed ECAP voltage amplitude and the stimulation current amplitude. For example, the control pulse current amplitude 1002 and the notification pulse current amplitude 1004 are plotted together with the ECAP voltage amplitude 1008 as a function of time, thus showing how the stimulation current amplitude varies relative to the ECAP voltage amplitude. In some examples, IMD 200 delivers multiple control pulses and multiple notification pulses, respectively, with control pulse current amplitude 1002 and notification pulse current amplitude 1004. Initially, IMD 200 may deliver a first set of control pulses, wherein IMD 200 delivers the first set of control pulses with a current amplitude I2. Additionally, IMD 200 may deliver a first set of notification pulses, wherein IMD 200 delivers the first set of control pulses with a current amplitude I1. I1 and I2 may be referred to as predetermined values ​​for the amplitudes of the corresponding control pulses and notification pulses. This predetermined value can be a programmed value or a value selected in another way, chosen by the stimulation procedure to at least partially define the stimulation pulse for the patient in the absence of transient conditions (e.g., when the ECAP amplitude is below a threshold ECAP value). The first set of control pulses and the first set of notification pulses can be delivered before time T1. In some examples, I1 is 4 mA and I2 is 8 mA. Although the control pulse current amplitude 1002 is shown as greater than the notification pulse current amplitude 1004, in other examples, the control pulse current amplitude 1002 may be less than or equal to the notification pulse current amplitude 1004.

[0155] During the delivery of the first set of control pulses and the first set of notification pulses, the IMD 200 can record the ECAP voltage amplitude 1008. During dynamic and transient conditions occurring in patient 105 (such as coughing, sneezing, laughing, Valsalva maneuver, leg raising, neck movement, or deep breathing), if the control pulse current amplitude 1002 and the notification pulse current amplitude 1004 remain constant, the ECAP voltage amplitude 1008 may increase. This increase in the ECAP voltage amplitude 1008 may be due to a decrease in the distance between the electrode and the nerve. For example, as... Figure 10 As shown, when the stimulation current amplitude remains constant, the ECAP voltage amplitude 1008 can increase before time T1. The increased ECAP voltage amplitude 1008 may indicate that the patient 105 is at risk of experiencing transient overstimulation due to the control pulses and notification pulses delivered by the IMD 200. To prevent the patient 105 from experiencing transient overstimulation, the IMD 200 can decrease the control pulse current amplitude 1002 and the notification pulse current amplitude 1004 in response to the ECAP voltage amplitude 1008 exceeding the threshold ECAP amplitude 1006. For example, if the IMD 200 senses that the ECAP voltage amplitude 1008 of the ECAP reaches or exceeds the threshold ECAP amplitude 1006, as... Figure 10As shown in time T1, IMD 200 can enter a decrementing mode, where the control pulse current amplitude 1002 and the notification pulse current amplitude 1004 are reduced. In some examples, the threshold ECAP amplitude 1006 is selected from the range of approximately 5 microvolts (μV) to approximately 30 μV, or from the range of approximately 10 microvolts (μV) to approximately 20 μV. For example, the threshold ECAP amplitude 1006 is 15 μV. In other examples, the threshold ECAP amplitude 1006 is less than or equal to 5 μV or greater than or equal to 30 μV.

[0156] The IMD 200 can respond relatively quickly to ECAP voltage amplitudes 1008 exceeding a threshold ECAP amplitude 1006. For example, the IMD can be configured to detect ECAP amplitudes exceeding the threshold within 20 milliseconds (ms). If the IMD 200 delivers a control pulse at a frequency of 50 Hz, the time interval for a single sample, including the delivery of the control pulse and the detection of the resulting ECAP signal, can be 20 ms or less. However, since the ECAP signal may appear within one or two milliseconds after the delivery of the control pulse, the IMD 200 can be configured to detect ECAP signals exceeding the threshold ECAP amplitude within less than 10 ms. For transient conditions, such as a patient coughing or sneezing, these sampling intervals are sufficient to identify ECAP amplitudes exceeding the threshold and to responsively reduce the amplitude of subsequent pulses before the ECAP amplitude reaches a higher level that may cause discomfort to the patient.

[0157] In some cases, the decrementing pattern can be stored as part of the control policy 213 in the storage device 212 of the IMD 200. Figure 10In the example shown, the decreasing mode is executed by IMD 200 on a second set of control pulses and a second set of notification pulses occurring between time T1 and time T2. In some examples, to execute the decreasing mode, IMD 200 reduces the control pulse current amplitude 1002 of each control pulse in the second set of control pulses according to a first function with respect to time. In other words, IMD 200 reduces each consecutive control pulse in the second set of control pulses proportionally to the amount of time elapsed since the previous control pulse. Additionally, during the decreasing mode, IMD 200 can reduce the notification pulse current amplitude 1004 of each notification pulse in the second set of notification pulses according to a second function with respect to time. Although linear first and second functions are shown, in other examples, the first and / or second functions can be nonlinear, such as logarithmic functions (e.g., a rate of change decreasing with time), exponential functions (e.g., a rate of change increasing with time), parabolic functions, step functions, multiple different functions, etc. During the time period when the IMD200 operates in decrement mode (e.g., time interval T2-T1), the ECAP voltage amplitude 1008 sensed by the IMD200 can be greater than or equal to the threshold ECAP amplitude 1006.

[0158] exist Figure 2 In the example shown, IMD 200 can sense ECAP at time T2, where ECAP has an ECAP voltage amplitude 1008 that is less than the threshold ECAP amplitude 1006. In some cases, the ECAP sensed at time T2 may be the first ECAP with an amplitude below the threshold sensed by IMD 200 since IMD 200 started the decrementing mode at time T1. Based on the ECAP sensed at time T2, IMD 200 can deactivate the decrementing mode and activate the incrementing mode. In some cases, the incrementing mode may be stored in the storage device 212 of IMD 200 as part of control strategy 213. IMD 200 can execute the incrementing mode on a third set of control pulses and a third set of notification pulses occurring between time T2 and time T3. In some examples, to execute the incrementing mode, IMD 200 increases the control pulse current amplitude 1002 of each control pulse in the third set of control pulses according to a third function relating to time. In other words, IMD 200 increases each consecutive control pulse in the third set of control pulses proportionally to the amount of time elapsed since the previous control pulse. Additionally, during the increment mode, IMD 200 can increase the notification pulse current amplitude 1004 of each notification pulse in the third set of notification pulses according to a fourth function relating to time.

[0159] like Figure 10As shown, IMD 200 is configured to decrease the amplitude at a faster rate than it increases after the ECAP voltage amplitude 1008 drops below the threshold ECAP amplitude 1006. In other examples, the rate of change may be similar during the decreasing and increasing modes. In other examples, IMD 200 may be configured to increase the amplitude of the notification pulse and control pulse at a faster rate than when decreasing the amplitude. In other examples, the rate of change of the pulse amplitude may be relatively instantaneous (e.g., a very fast rate). For example, in response to the ECAP voltage amplitude 1008 exceeding the threshold ECAP amplitude 1006, IMD 200 may immediately reduce the amplitude of one or both of the control pulse current amplitude 1002 or the notification pulse current amplitude 1004 to a predetermined or calculated value. Then, in response to the ECAP voltage amplitude 1008 falling back below the threshold ECAP amplitude 1006, IMD 200 may enter the increasing mode as described above.

[0160] When the control pulse current amplitude 1002 and the notification pulse current amplitude 1004 return to current amplitudes I2 and I1, respectively, the IMD 200 can deactivate the incremental mode and deliver stimulation pulses with a constant current amplitude. By reducing stimulation in response to the ECAP amplitude exceeding a threshold and subsequently increasing stimulation in response to the ECAP amplitude falling below a threshold, the IMD 200 can prevent patient 105 from experiencing transient hyperstimulation or reduce the severity of transient hyperstimulation experienced by patient 105, whether by reducing the duration, relative intensity, or both.

[0161] Figure 10 This is described in the case where the IMD 200 simultaneously delivers control pulses and notification pulses. However, the IMD 200 can... Figure 10 The technology is applied to situations where only control pulses are delivered to provide treatment to the patient. In this way, the IMD 200 will similarly enter a decreasing or increasing mode for the control pulse current amplitude 1002 based on the detected ECAP voltage amplitude 1008, without adjusting the amplitude or other parameters of any other type of stimulation pulse.

[0162] Figure 11 The flowchart illustrates an example operation of controlling stimuli based on one or more sensed ECAPs, according to one or more techniques disclosed herein. Figure 11 Similar to the above Figure 9 The difference is that, Figure 11 A buffer defined by an upper and lower threshold is used, which defines when the amplitude value increases or decreases. For convenience, refer to... Figure 2 IMD 200 description Figure 11 .However, Figure 11The technology can be performed by different components of the IMD 200 or by additional or alternative medical devices.

[0163] The stimulation generation circuit 202 of the IMD 200 can deliver electrical stimulation therapy to a patient (e.g., patient 105). To control the electrical stimulation therapy, the processing circuit 210 can guide the delivery of at least some stimulation pulses according to a treatment stimulation program 214 stored in the storage device 212, wherein the electrical stimulation therapy may include multiple control pulses and / or notification pulses. In some cases, the notification pulses may generate an ECAP that can be detected by the IMD 200. However, in other cases, the polarization of the notification pulses may interfere with the sensing of the ECAP in response to the notification pulses. In some examples, to induce an ECAP that can be detected by the IMD 200, the stimulation generation circuit 202 delivers multiple control pulses, which are interleaved with at least some of the notification pulses. The processing circuit 210 can control the delivery of the control pulses according to an ECAP testing stimulation program 216. Because the control pulses can be interleaved with the notification pulses, the sensing circuit 206 of the IMD 200 can detect multiple ECAPs. The sensing circuit 206 is configured to detect each of the multiple ECAPs after one of the control pulses and before a subsequent notification pulse of the multiple notification pulses. In this way, the IMD 200 can induce multiple ECAPs in the target tissue by delivering control pulses, without the notification pulses interfering with the IMD 200's sensing of the ECAPs.

[0164] like Figure 11 As shown, processing circuitry 210 instructs stimulation generation circuitry 202 to deliver control pulses (1102). Stimulation generation circuitry 202 can deliver control pulses to target tissue of patient 105 via any combination of electrodes 232, 234 of lead 230. In some examples, the control pulse may include a balanced biphasic square wave pulse employing an active charging phase. However, in other examples, the control pulse may include a monophasic pulse followed by a passive charging phase. In other examples, the control pulse may include an unbalanced biphasic portion and a passive charging portion. Although not strictly necessary, biphasic control pulses may include an interphase interval between the positive and negative phases to facilitate nerve impulse propagation in response to the first phase of the biphasic pulse. The control pulse may have a pulse width of approximately 300 μs, such as a biphasic pulse with a duration of approximately 100 μs per phase.

[0165] After the delivery of the control pulse, the IMD 200 attempts to detect the ECAP (1104). For example, the sensing circuit 206 can monitor signals from any combination of electrodes 232, 234 of the lead 230. In some examples, the sensing circuit 206 detects the ECAP from a specific combination of electrodes 232, 234. In some cases, the specific combination of electrodes used to sense the ECAP includes electrodes different from the set of electrodes 232, 234 used to deliver the stimulation pulse. Alternatively, in other cases, the specific combination of electrodes used to sense the ECAP includes at least one of the same set of electrodes used to deliver the stimulation pulse to the patient 105. In some examples, the specific combination of electrodes used to sense the ECAP may be located on the opposite side of the lead 230 to the specific combination of electrodes used to deliver the stimulation pulse. The IMD 200 can detect the ECAP in response to the control pulse. The IMD 200 can measure one or more characteristics of the responsive ECAP, such as ECAP amplitude, ECAP duration, peak-to-peak duration, or any combination thereof. For example, to measure the magnitude of ECAP, the IMD 200 can determine the voltage difference between the peak value of N1 ECAP and the peak value of P2 ECAP.

[0166] At block 1106, processing circuitry 210 determines whether the ECAP amplitude of the responsive ECAP is greater than an upper limit ECAP amplitude threshold. If the ECAP amplitude is greater than the upper limit ECAP amplitude threshold (the "Yes" branch of block 1106), processing circuitry 210 activates / continues a decreasing mode in IMD 200 (1108). For example, if a decreasing mode is already "on" in IMD 200 when processing circuitry determines that the ECAP amplitude is greater than the upper limit ECAP amplitude threshold, processing circuitry 210 keeps IMD 200 in decreasing mode. If a decreasing mode is "off" in IMD 200 when processing circuitry determines that the ECAP amplitude is greater than the upper limit ECAP amplitude threshold, processing circuitry 210 activates a decreasing mode to reduce the pulse amplitude from a predetermined value programmed for the stimulus. In some examples, the decreasing mode may be stored in storage device 212 as part of control strategy 213. The decreasing mode may be a set of instructions that cause IMD 200 to decrease one or more parameter values ​​for each consecutive notification pulse and decrease one or more parameter values ​​for each consecutive control pulse. For example, when the decrement mode is activated, processing circuit 210 can reduce the current amplitude of each successive notification pulse delivered by IMD 200 and reduce the current amplitude of each successive control pulse delivered by IMD 200. After processing circuit 210 activates / continues the decrement mode, the example operation can return to block 1102, and IMD 200 can deliver another control pulse.

[0167] If the ECAP amplitude is not greater than the ECAP amplitude threshold (the "No" branch of box 1106), then processing circuitry 210 determines at box 1110 whether the ECAP amplitude is less than the lower limit ECAP amplitude threshold. If the ECAP amplitude is less than the lower limit ECAP amplitude threshold (the "Yes" branch of box 1110), then processing circuitry 210 activates an increment mode (1112) in IMD 200. In some examples, the increment mode may be stored in storage device 212 as part of control strategy 213. The increment mode may be a set of instructions that cause IMD 200 to increment one or more parameter values ​​for each consecutive notification pulse and to increment one or more parameter values ​​for each consecutive control pulse. For example, when the increment mode is activated, processing circuitry 210 may increase the current amplitude of each consecutive notification pulse delivered by IMD 200 and increase the current amplitude of each consecutive control pulse delivered by IMD 200. After processing circuitry 210 activates the increment mode, the example operation may return to box 1102, and IMD 200 may deliver another control pulse. The processing circuit 210 can continue to increment the pulse amplitude until the pulse amplitude returns to a predetermined value that was programmed to be used for delivery before the ECAP amplitude exceeds the upper limit ECAP amplitude threshold.

[0168] If the ECAP amplitude is not less than the lower limit ECAP amplitude threshold (the "No" branch of box 1110), then processing circuit 1114 maintains the pulse amplitude currently used to at least partially define the parameter value. In this way, when the ECAP amplitude is between the upper and lower limit ECAP amplitude thresholds, processing circuit 210 does not increase the amplitude value back to a predetermined value or decrease the amplitude. This "buffer" region can reduce the amplitude value of oscillations when the ECAP amplitude is similar to the ECAP amplitude threshold. These oscillation amplitude values ​​may be perceived as uncomfortable or unwanted by the patient. However, once the ECAP amplitude drops below the lower limit ECAP amplitude threshold, processing circuit 210 can return the amplitude value to the predetermined amplitude value intended for therapeutic use.

[0169] In some examples, an upper limit ECAP amplitude threshold and a lower limit ECAP amplitude threshold are defined. In other examples, processing circuitry 210 may define the upper limit ECAP amplitude threshold and / or the lower limit ECAP amplitude threshold as a buffer or deviation from a single defined ECAP threshold. For example, processing circuitry 210 may define the lower limit ECAP amplitude threshold based on an upper limit ECAP amplitude threshold defined by the user or calculated based on an initial patient-perceived threshold and / or discomfort threshold. Although Figure 11 The amplitude of both the notification pulse and the control pulse is described, but when the IMD 200 only delivers a control pulse to the patient (e.g., no notification pulse) for treatment, Figure 11 The technology is also applicable.

[0170] Figure 12 According to one or more techniques disclosed herein, a voltage / current / time graph 1200 is shown, which plots the control pulse current amplitude 1202, the notification pulse current amplitude 1204, and the ECAP voltage amplitude 1210 as a function of time. Additionally, Figure 12 The upper threshold ECAP range of 1206 and the lower threshold ECAP range of 1208 are shown. Figure 12 It can be similar to Figure 10 ,but Figure 12 This demonstrates a technique that uses two thresholds for the ECAP voltage amplitude 1210 to provide buffering, which reduces the potential oscillation of the pulse amplitude when the ECAP amplitude oscillates around a single ECAP amplitude threshold. For convenience, refer to... Figure 2 IMD 200 description Figure 10 .However, Figure 12 The technology can be performed by different components of the IMD 200 or by additional or alternative medical devices.

[0171] Voltage / current / time plot 1200 illustrates the relationship between the sensed ECAP voltage amplitude and the stimulation current amplitude. For example, the control pulse current amplitude 1202 and the notification pulse current amplitude 1204 are plotted together with the ECAP voltage amplitude 1210 as a function of time, thus showing how the IMD 200 is configured to vary the stimulation current amplitude relative to the detected ECAP voltage amplitude (or some other ECAP characteristic value). In some examples, the IMD 200 delivers multiple control pulses and multiple notification pulses, respectively, with control pulse current amplitude 1202 and notification pulse current amplitude 1204. Initially, the IMD 200 may deliver a first set of control pulses, wherein the IMD 200 delivers the first set of control pulses with a current amplitude I2. Additionally, the IMD 200 may deliver a first set of notification pulses, wherein the IMD 200 delivers the first set of notification pulses with a current amplitude I1. I1 and I2 may be referred to as predetermined values ​​for the amplitudes of the corresponding control pulses and notification pulses. This predetermined value can be a programmed value or a value selected in another way, chosen by the stimulation procedure to at least partially define the stimulation pulse for the patient in the absence of transient conditions (e.g., when the ECAP amplitude is below a threshold ECAP value). The first set of control pulses and the first set of notification pulses can be delivered before time T1. In some examples, I1 is 4 mA and I2 is 8 mA. Although the notification pulse current amplitude 1202 is shown as greater than the control pulse current amplitude 1204, in other examples, the notification pulse current amplitude 1202 may be less than or equal to the control pulse current amplitude 1204.

[0172] During the delivery of the first set of control pulses and the first set of notification pulses, the IMD 200 can determine the ECAP voltage amplitude 1210 based on the corresponding ECAP signal. During dynamic and transient conditions occurring in the patient 105 (such as coughing, sneezing, laughing, Valsalva maneuver, leg raising, neck movement, or deep breathing), if the control pulse current amplitude 1202 and the notification pulse current amplitude 1204 remain constant, the ECAP voltage amplitude 1210 may increase. This increase in the ECAP voltage amplitude 1210 may be due to a decrease in the distance between the electrode and the nerve. For example, as... Figure 12 As shown, when the stimulation current amplitude remains constant, the ECAP voltage amplitude 1208 can increase before time T1. An increased ECAP voltage amplitude 1208 may indicate that patient 105 is at risk of experiencing transient overstimulation due to the control and notification pulses delivered by IMD 200. However, IMD 200 may take no action until the ECAP voltage amplitude 1210 exceeds or is greater than the upper limit threshold ECAP amplitude 1206. To prevent patient 105 from experiencing transient overstimulation, IMD 200 may reduce the control pulse current amplitude 1202 and the notification pulse current amplitude 1204 in response to the ECAP voltage amplitude 12010 exceeding the upper limit threshold ECAP amplitude 1206. For example, if IMD 200 senses that the ECAP voltage amplitude 1210 of the ECAP reaches or exceeds the upper limit threshold ECAP amplitude 1206, as... Figure 12 As shown in time T1, IMD 200 can enter a decrementing mode, where IMD 200 reduces the control pulse current amplitude 1202 and the notification pulse current amplitude 1204. In some examples, the upper limit threshold ECAP amplitude 1206 is selected from the range of approximately 5 microvolts (μV) to approximately 30 μV, or from the range of approximately 10 microvolts (μV) to approximately 20 μV. For example, the upper limit threshold ECAP amplitude 1206 is 15 μV. In other examples, the upper limit threshold ECAP amplitude 1206 is less than or equal to 5 μV or greater than or equal to 30 μV. In some examples, IMD 200 can determine the upper limit threshold ECAP amplitude 1206 based on a target threshold, such that the upper limit threshold ECAP amplitude 1206 is higher than the target threshold and the lower limit threshold ECAP amplitude 1208 is lower than the target threshold.

[0173] The IMD 200 can respond relatively quickly to ECAP amplitudes 1210 exceeding the upper threshold ECAP amplitude 1206. For example, the IMD can be configured to detect ECAP amplitudes exceeding the threshold within 20 milliseconds (ms). If the IMD 200 delivers a control pulse at a frequency of 50 Hz, the time interval for a single sample, including the delivery of the control pulse and the detection of the resulting ECAP signal, can be 20 ms or less. However, since the ECAP signal may appear within one or two milliseconds after the delivery of the control pulse, the IMD 200 can be configured to detect ECAP signals exceeding the threshold ECAP amplitude within less than 10 ms. For transient conditions, such as a patient coughing or sneezing, these sampling intervals are sufficient to identify ECAP amplitudes exceeding the threshold and to responsively reduce the amplitude of subsequent pulses before the ECAP amplitude reaches a higher level that may cause discomfort to the patient.

[0174] In some cases, the decrementing pattern can be stored as part of the control policy 213 in the storage device 212 of the IMD 200. Figure 10 In the example shown, the decreasing mode is executed by IMD 200 on a second set of control pulses and a second set of notification pulses occurring between time T1 and time T2. In some examples, to execute the decreasing mode, IMD 200 reduces the control pulse current amplitude 1202 of each control pulse in the second set of control pulses according to a first function with respect to time. In other words, IMD 200 reduces each consecutive control pulse in the second set of control pulses proportionally to the amount of time elapsed since the previous control pulse. Additionally, during the decreasing mode, IMD 200 can reduce the notification pulse current amplitude 1204 of each notification pulse in the second set of notification pulses according to a second function with respect to time. Although linear first and second functions are shown, in other examples, the first and / or second functions can be nonlinear, such as logarithmic functions (e.g., a rate of change decreasing with time), exponential functions (e.g., a rate of change increasing with time), parabolic functions, step functions, multiple different functions, etc. During the time period when the IMD200 operates in decrement mode (e.g., time interval T2-T1), the ECAP voltage amplitude 1210 sensed by the IMD200 can be greater than or equal to the upper limit threshold ECAP amplitude 1206.

[0175] exist Figure 12In the example shown, IMD 200 can sense ECAP at time T2, where ECAP has an ECAP voltage amplitude 1210 that is less than the upper threshold ECAP amplitude 1206. However, the ECAP voltage amplitude 1210 may still be greater than the lower threshold ECAP amplitude 1208. In this region between the upper threshold ECAP amplitude 1206 and the lower threshold ECAP amplitude 1208, IMD 200 can maintain the control pulse current amplitude 1202 and the notification pulse current amplitude 1204 (e.g., between T2 and T3). By responding to a drop in ECAP voltage amplitude 1210 below the upper threshold ECAP amplitude 1206 without immediately increasing the amplitudes of the control pulse current amplitude 1202 and the notification pulse current amplitude 1204, IMD 200 can prevent these pulse amplitudes from increasing again due to only another spike in ECAP voltage amplitude 1210. These subsequent spikes, which may be perceived by the patient, have undesirable fluctuations or oscillations in treatment intensity. The lower threshold ECAP amplitude 1208 can be set as a certain percentage of the upper threshold ECAP amplitude 1206 or the target threshold, or as an absolute value lower than the upper threshold ECAP amplitude or the target threshold. In some examples, the region between the upper threshold ECAP amplitude 1206 and the lower threshold ECAP amplitude 1208 can have a predetermined amplitude and / or be adjustable by the patient or physician. For example, if the patient is still experiencing oscillations in treatment intensity, the upper threshold ECAP amplitude 1206 and / or the lower threshold ECAP amplitude 1208 can be adjusted to increase said region.

[0176] At time T3, IMD 200 can again detect that the ECAP voltage amplitude 1210 exceeds the upper threshold ECAP amplitude 1206 and responsively further reduce the control pulse current amplitude 1202 and the notification pulse current amplitude 1204. At time T4, the ECAP voltage amplitude 1210 drops below the upper threshold ECAP amplitude 1206 but remains above the lower threshold ECAP amplitude 1208. Therefore, between times T4 and T5, IMD 200 can maintain the control pulse current amplitude 1202 and the notification pulse current amplitude 1204. At time T5, IMD 200 determines that the ECAP voltage amplitude 1210 has dropped below and is less than the lower threshold ECAP amplitude 1208. In response to the ECAP voltage amplitude 1210 dropping below the lower threshold ECAP amplitude 1208, IMD 200 can begin to increase the control pulse current amplitude 1202 and the notification pulse current amplitude 1204, returning to the corresponding predetermined values ​​I1 and I2 at time T6. If the ECAP voltage amplitude 1210 exceeds the upper limit threshold ECAP amplitude 1206 again before time T6, then IMD 200 will reduce the control pulse current amplitude 1202 and the notification pulse current amplitude 1204 as discussed above regarding the time period between T1 and T2.

[0177] In other examples, the rate of change of the pulse amplitude can be relatively instantaneous (e.g., a very fast rate). For example, in response to the ECAP voltage amplitude 1210 exceeding the upper threshold ECAP amplitude 1206, the IMD 200 can immediately reduce the amplitude of one or both of the control pulse current amplitude 1202 or the notification pulse current amplitude 1204 to a predetermined or calculated value. Then, in response to the ECAP voltage amplitude 1210 falling back below the lower threshold ECAP amplitude 1208, the IMD 200 can enter an incrementing mode as described above.

[0178] When the control pulse current amplitude 1002 and the notification pulse current amplitude 1004 return to current amplitudes I2 and I1 (e.g., predetermined or programmed values ​​for each type of pulse), the IMD 200 can deactivate the incremental mode and deliver stimulation pulses again at a constant current amplitude. By reducing stimulation in response to the ECAP amplitude exceeding the upper threshold and subsequently increasing stimulation in response to the ECAP amplitude falling below the lower threshold, the IMD 200 can prevent the patient 105 from experiencing transient overstimulation or reduce the severity of transient overstimulation experienced by the patient 105, whether by reducing the duration, relative intensity, or both, while also reducing potential oscillations that may occur in a single-threshold condition.

[0179] Figure 12 This is described in the case where the IMD 200 simultaneously delivers control pulses and notification pulses. However, the IMD 200 can... Figure 10 The technology is applied to situations where only control pulses are delivered to provide treatment to the patient and elicit a detectable ECAP signal. In this way, the IMD 200 will similarly enter a decreasing or increasing mode for the control pulse current amplitude 1202 based on the detected ECAP voltage amplitude 1210, without adjusting the amplitude or other parameters of any other type of stimulation pulse.

[0180] Figure 13 This is a block diagram illustrating a system 1300 for determining a control strategy 1300 for an IMD, based on one or more techniques disclosed herein. Figure 13 As shown, the system 1300 includes a user interface 1302, a control strategy monitoring unit 1310, a diagnostic / debugging unit 1320, a status classification unit 1330, a control strategy unit 1340, and a stimulus configuration unit 1350.

[0181] In some examples, the state classification unit 1330 can estimate the state of the monitored system based on input data. For example, the ECAP can represent the input of the state classification unit 1330 to estimate tissue activation (e.g., ECAP characteristic value) during the delivery of one or more stimulation pulses to a target tissue of the patient (e.g., the spinal cord 120 of patient 105). The state classification unit 1330 can generate one or more outputs to be sent to the control strategy unit 1340. Furthermore, the control strategy unit 1340 can receive one or more outputs from the state classification unit 1330 and receive one or more additional inputs from other parts of the system or external sources (e.g., modulated signals, patient inputs, control strategy monitoring unit 1310). The control strategy unit 1340 can determine a control strategy based on the received inputs, wherein the control strategy drives one or more treatment configuration updates at the stimulation configuration unit 1350. Adjustments to the state classification unit 1330 and the control strategy unit 1340 may be beneficial when patient symptoms and other factors change (e.g., lead migration).

[0182] System 1300 can monitor the properties of input data (e.g., the output of state classification unit 1330 and the output of control strategy monitoring unit 1310) and generate control strategies to improve the performance of IMD 110 compared to systems that do not use input data to determine control strategies. For example, compared to systems that do not determine control strategies based on measured signals, system 1300 can reduce the number of patient interactions required to update system configuration and reduce the number of sudden, undesirable changes in the level of sensory abnormalities perceived by IMD 110 (e.g., transient overstimulation events). Additionally, control strategy unit 1340 can adjust the stimuli delivered by IMD 110 based on the time of day.

[0183] like Figure 13As shown, the input signals (e.g., physiological signal 1332 and inertial signal 1336) can be modulated by signal conditioning unit 1334 and signal conditioning unit 1338, respectively. In some examples, physiological signal 1332 may include cardiac signals (e.g., heart rate, heart rate variability, blood pressure, and blood pressure variability), respiratory signals (e.g., respiratory rate and respiratory rate variability), and ECAP. In some examples, inertial signal 1336 may include accelerometer data and / or gyroscope data indicating patient movement and posture. During conditioning, one or more features may be calculated to identify one or more attributes of the input signals. State classification unit 1330 may use these attributes to classify the state of the stimulus delivered by IMD 110 (e.g., too much or too little activated tissue). The determined state may be used as input to a control strategy determined by control strategy unit 1340. Other inputs to control strategy unit 1340 may include one or more user inputs from user interface 1302 and one or more inputs from control strategy monitoring unit 1310. After the control strategy unit 1340 determines the control strategy based on the input, the control strategy unit 1340 can output instructions to use the stimulus configuration unit 1350 to set one or more stimulus parameters.

[0184] In some examples, one or more configurable parameters defining the control strategy may be determined by the control strategy unit 1340. These parameters may include, for example, upper and lower limits of the buffer, an overstimulation threshold, a maximum stimulation amplitude, a minimum stimulation amplitude, a stimulation increment step size, a stimulation increment step duration, a stimulation decrement step size, a stimulation decrement step duration, and a scaling factor between the control pulse amplitude and the notification pulse amplitude. Attributes monitored by the control strategy monitoring unit 1310 may include, for example, any one or a combination of the following: the number of state changes over a period of time, the number, frequency, or time of day of patient adjustments, the lack of control strategy state changes, reported undesirable stimulus events, and changes in stimulation amplitude.

[0185] In some examples, the processing circuitry (e.g., the processing circuitry of IMD 110 and / or the processing circuitry of external programmer 150) can execute any one or a combination of the control strategy monitoring unit 1310, the diagnostic / debugging unit 1320, the state classification unit 1330, the control strategy unit 1340, and the stimulus configuration unit 1350.

[0186] Figure 14 This is a flowchart illustrating example operations for adjusting the control strategy of the IMD 110, based on one or more techniques disclosed herein. About Figure 1 IMD 110 and external programmer 150, Figure 2 IMD 200 and Figure 3The external programmer 300 is described Figure 14 .However, Figure 14 The technology can be performed by different components of IMD 110, external programmer 150, IMD 200 and external programmer 300, or by additional or alternative medical devices.

[0187] The processing circuitry can record the occurrence of self-monitoring events and record one or more updated settings associated with the self-monitoring events (1402). The processing circuitry can determine whether the number of control strategy state changes within a first duration exceeds a threshold number of control strategy state changes (1404). When the number of control strategy state changes exceeds the threshold number of control strategy state changes (the "Yes" branch of box 1404), the processing circuitry can determine whether an undesirable patient indication of abnormal sensation has been received (1406). When no undesirable patient indication of abnormal sensation has been received (the "No" branch of box 1406), the processing circuitry can determine whether a patient indication of reduced treatment benefit has been received (1408). When no patient indication of reduced treatment benefit has been received (the "No" branch of box 1408), the processing circuitry can determine that no control strategy change is required.

[0188] When a patient indication of undesirable abnormal sensation is received ("Yes" branch of box 1406) or when a patient indication of reduced treatment benefit is received ("Yes" branch of box 1408), the processing circuitry may perform a lead integrity test (1410) on one or more leads 130. Subsequently, the processing circuitry may execute a "patient guidance wizard" algorithm (1412). After executing the patient guidance wizard algorithm, the processing circuitry may recommend one or more control strategy changes for implementation by the IMD 110.

[0189] When the number of control strategy state changes is not greater than the threshold number of control strategy state changes (the "No" branch of box 1404), the processing circuit can determine whether zero state changes occurred during the second duration (1414). If zero state changes occurred during the second duration (the "Yes" branch of box 1414), the processing circuit can perform a lead integrity test on one or more leads 130 (1410). If more than zero state changes occurred during the second duration (the "No" branch of box 1414), the processing circuit determines whether the number of patient parameter adjustments during the third duration is greater than the threshold number of patient parameter adjustments (1416). If the number of patient parameter adjustments during the third duration is greater than the threshold number of patient parameter adjustments (the "Yes" branch of box 1416), the processing circuit can perform a lead integrity test on one or more leads 130 (1410). If the number of patient parameter adjustments during the third duration is not greater than the threshold number of patient parameter adjustments (the "No" branch of box 1416), then the external programmer 150 can determine whether an indication of discomfort has been received (1418). Discomfort may be referred to herein as "zinger." The processing circuitry can be configured to communicate with the external programmer, for example... Figure 3 An external programmer 300. A user interface 356 can receive user input indicating unwanted sensory attributes and direct the user input to the processing circuitry.

[0190] When the processing circuitry determines that it has received an indication of discomfort (the "Yes" branch of box 1418), it outputs a request to record the histogram data stored in the rolling buffer (1420) of the IMD 110. In some examples, the processing circuitry may receive and analyze the histogram data, which represents the histogram data of a set of ECAPs sensed by the IMD 110 in response to a stimulus pulse delivered by the IMD 110. To analyze the histogram data, the processing circuitry may determine whether one or more ECAP features exceed an ECAP feature threshold (1422). For example, if the histogram data indicates that one or more ECAP features do not exceed an ECAP feature threshold (the "No" branch of box 1422), the processing circuitry may initiate a patient guidance wizard (1412) to obtain information related to the discomfort indicated by the patient. When histogram data indicates that one or more ECAP features do indeed exceed the ECAP feature threshold (the "Yes" branch of box 1422), the processing circuitry can output a recommendation to modify the control strategy of IMD 110 by increasing the decrement step size (1424) of one or more stimulation pulses delivered by IMD 110. For example, IMD 110 can be programmed to decrement the stimulation pulses in response to the detection of an increase in ECAP amplitude. By increasing the decrement step size, the processing circuitry can reduce the likelihood that patient 105 will experience transient overstimulation events in the future.

[0191] When the processing circuitry determines that no indication of discomfort is received (No branch of box 1418), it can determine whether there is a trend in the amplitude of the stimulus pulses delivered by IMD 110 over a period of time (1426). When the processing circuitry identifies a trend (Yes branch of box 1426), it determines the current posture of patient 105 based on accelerometer data and records the current time of day during the period in which the trend occurred (1428). This trend can represent the trend of the stimulus amplitude that evokes the desired sensation in patient 105 when the patient adopts this posture. The processing circuitry can determine whether this trend has occurred more than a threshold number of times over a period of time (1430). If the trend has occurred more than the threshold number of times (Yes branch of box 1430), the processing circuitry can determine whether the trend is related to the posture of patient 105 (1432). If the processing circuitry determines that the trend is posture-related (the "Yes" branch of box 1432), it can add a new state to the control policy (1434) of the IMD 110, which updates one or more stimulus parameters when the trend is detected. If the processing circuitry determines that the trend is not posture-related (the "No" branch of box 1432), it can add a new state to the control policy (1436) of the IMD 110, which updates one or more stimulus parameters at the time of day when the trend is detected.

[0192] Figure 15 This is a flowchart illustrating example operations for generating recommended procedures for controlling one or more treatment parameters, based on one or more techniques disclosed herein. For convenience, regarding... Figure 1 IMD 110 and external programmer 150, Figure 2 IMD 200 and Figure 3 The external programmer 300 is described Figure 15 .However, Figure 15 The technology can be performed by different components of IMD 110, external programmer 150, IMD 200 and external programmer 300, or by additional or alternative medical devices.

[0193] The processing circuitry can execute an algorithm to recommend changes to a control strategy that determines one or more parameters of the electrical stimulation delivered by the IMD 110. For example, it may be beneficial to customize the electrical stimulation parameters on a patient-by-patient basis, as the way the lead 130 is implanted may differ slightly from patient to patient. For instance, the distance between electrodes 232, 234 and the target tissue of patient 105 may differ from the distance between electrodes and the target tissue of another patient. Additionally, the lead 130 may migrate within patient 105 over a period of time, thereby altering the stimulation parameters required for patient 105 to experience the desired effect. The processing circuitry can execute the algorithm to obtain information for determining one or more parameter recommendations to prevent the IMD 110 from delivering transient overstimulation to patient 105.

[0194] The processing circuit can output a message requesting the patient 105 to perform an action for the user interface (e.g., Figure 3 The user interface 356 is displayed (1502). The message displayed on the user interface can be in text form, such as “Cough once” or “Please arch your back”, but this is not required. The message may include symbols, such as symbols depicting the action prompted to be performed by patient 105. In some examples, the processing circuitry may output a message in response to receiving an instruction to execute the algorithm. In some examples, the processing circuitry outputs a message even without receiving a prompt to output a message. The processing circuitry may receive a message indicating that the action has been completed, but this is not required. In some examples, the processing circuitry may continue the algorithm even without receiving an indication that the action of patient 105 has been completed.

[0195] The processing circuitry can output a set of requests (1504) for display on the user interface. The processing circuitry can output this set of requests sequentially. That is, the processing circuitry can output a first request for display, followed by a second request, then a third request, and so on. This set of requests can represent requests for information, such as requests for information about the presence or nature of one or more sensations experienced by patient 105 in relation to an action performed by patient 105. For example, the set of requests may include one or more requests prompting the user to indicate whether the action caused an undesirable attribute during and / or after the action. The set of requests may also include one or more requests prompting the user to indicate an identifier of an undesirable attribute (e.g., a strong sensation, increased position, pulsation, tingling, pressure, tapping, vibration, or any combination thereof).

[0196] In some examples, the processing circuitry may output one or more requests prompting the user to identify a sensation as a menu of sensations selectable via a user interface. In some examples, the processing circuitry may output one or more requests prompting the user to identify a sensation as a sequence of requests. Each request in the sequence of requests may include a prompt causing the patient 105 to indicate whether a particular sensation occurred in response to the action.

[0197] The processing circuitry can receive a set of responses (1506) from the user interface. In some examples, the set of responses may include a response corresponding to each request in the set of requests, but this is not required. In some examples, the set of responses may not include responses to one or more requests in the set of requests. When the first request in the set of requests includes a prompt that instructs the user whether the action caused an undesirable attribute during the action, the first response in the set of responses may include a "yes" or "no" response to indicate whether the action caused the undesirable attribute. In some examples, the processing circuitry may receive the set of responses as a sequence of responses. For example, the set of requests and the set of responses may be interleaved, such that the processing circuitry receives a response to the corresponding request before outputting subsequent requests in the request sequence. The processing circuitry may determine one or more parameters defining the electrical stimulation (1508) delivered by the IMD 110 based on the set of responses. The processing circuitry may determine one or more parameters based on whether the set of requests indicates an undesirable attribute, when the undesirable attribute occurs relative to the action, the identifier of the undesirable attribute, or any combination thereof.

[0198] Figure 16 This is a flowchart illustrating example operations for outputting one or more requests and receiving one or more responses to adjust stimulation of a patient by the IMD 110, based on one or more techniques disclosed herein. About Figure 1 IMD 110 and external programmer 150, Figure 2IMD 200 and Figure 3 The external programmer 300 is described Figure 16 .However, Figure 16 The technology can be performed by different components of IMD 110, external programmer 150, IMD 200 and external programmer 300, or by additional or alternative medical devices.

[0199] In some examples, Figure 16 Example operation involves outputting one or more requests and receiving one or more responses to these requests to determine one or more parameters for delivering electrical stimulation to patient 105. The processing circuitry can trigger the IMD 110 to collect one or more baseline measurements (1602). For example, before guiding patient 105 to perform any action, the processing circuitry can trigger the recording of baseline data in the neurostimulator, and the processing circuitry can prompt patient 105 to rate various sensory levels. Baseline measurements may include, for example, accelerometer data, temperature data, blood oxygen data, ECAP data, heart rate, blood pressure, tissue impedance, or any combination thereof. Subsequently, the IMD 110 can record the baseline measurements (1604).

[0200] The processing circuitry can trigger IMD 110 to begin continuous measurement (1606). For example, before instructing patient 105 to perform one or more actions, the processing circuitry can trigger IMD 110 to begin continuously recording parameters such as stimulus amplitude, ECAP characteristics, the current classification of the characteristics (e.g., stimulus characteristics and / or ECAP characteristics), the current control strategy state, or any combination thereof. Subsequently, the processing circuitry can output an instruction (1608) to cause patient 105 to perform the action. In some examples, box 1608 may be... Figure 15 Example of box 1502. After the output command, the processing circuitry can trigger the IMD 110 to stop recording continuous measurements (1610). In some examples, the processing circuitry can instruct the IMD 110 to perform continuous measurements, making data corresponding to one or more patient parameters accessible for analysis during the execution of the action. In some cases, the processing circuitry can analyze ECAP data during the execution of the action to determine adjustments to one or more stimulation parameters to avoid transient overstimulation.

[0201] The processing circuit can output a request indicating whether an undesirable sensory attribute occurred during the execution of the action (1612). If the processing circuit receives a response indicating that an undesirable attribute occurred during the action (the "Yes" branch of box 1612), the processing circuit can determine whether to change the control strategy for determining the electrical stimulation delivered by IMD 110 (1614). The processing circuit can determine whether to prompt the patient 105 to perform a new action or to prompt the patient 105 to perform the same action (1616). If the processing circuit receives a response indicating that no undesirable attribute occurred during the action (the "No" branch of box 1612), the processing circuit can output a request indicating whether an undesirable attribute occurred after the execution of the action (1618).

[0202] If the processing circuit receives an indication that an undesirable attribute response occurred after the action (the "Yes" branch of box 1618), the processing circuit can determine whether to change the control strategy for determining the electrical stimulation delivered by IMD 110 (1620), and then the example operation proceeds to box 1616. If the processing circuit receives an indication that no undesirable attribute response occurred after the action (the "No" branch of box 1618), the example operation proceeds to box 1616.

[0203] Figures 17A to 17B This is a flowchart illustrating example operations for outputting one or more requests and receiving one or more responses, based on one or more techniques disclosed herein. About Figure 1 IMD 110 and external programmer 150, Figure 2 IMD 200 and Figure 3 The external programmer 300 is described Figures 17A to 17B .However, Figures 17A to 17B The technology can be performed by different components of IMD 110, external programmer 150, IMD 200 and external programmer 300, or by additional or alternative medical devices.

[0204] In some examples, the processing circuitry outputs instructions for display by the user interface of the patient programmer (e.g., user interface 356 of the external programmer 300), indicating prompts for the patient 105 to perform an action. After the patient 105 completes the action, the external programmer 300 may "interview" the patient 105 to gather information about specific attributes of one or more sensations felt by the patient 105 during or near the time period in which the action was performed. In some examples, the processing circuitry may use the current settings of the control strategy in conjunction with patient-perceived input to determine recommended changes to the control strategy of the IMD 110. These recommended changes may be implemented automatically by the processing circuitry in some cases, or by a user (e.g., the patient 105 or a clinician) in others. After implementing the recommended changes, the processing circuitry may determine whether to output instructions for the patient 105 to repeat the action in order to perform a follow-up assessment to interview the patient 105 again. Compared to technologies that do not store patient responses, processing circuitry that stores patient responses over a period of time may be beneficial in order to employ smarter, more refined methods to modify stimulation parameters and store information about other stimuli and lead properties (e.g., lead migration).

[0205] The processing circuitry can receive an instruction to execute an inquiry procedure (1702). In some cases, the inquiry procedure may be referred to herein as a "patient guidance wizard." In some examples, the instruction to execute the inquiry procedure represents user input to the device (e.g., input to the user interface 356 of the external programmer 300). In some examples, the instruction to execute the inquiry procedure represents an automatic instruction, such as an instruction to execute the inquiry procedure periodically at a certain time. In some examples, the processing circuitry receives the instruction in response to the external programmer 300 being turned on. In some examples, the processing circuitry can respond to... Figure 14 The example operation reaches box 1412 and receives an instruction to execute the query procedure.

[0206] To initiate the interrogation procedure, the processing circuitry triggers one or more baseline measurements (1704). In some examples, the one or more baseline measurements may include biomarker measurements and system state measurements. For example, baseline measurements may include one or more of the following: baseline ECAP measurement, baseline heart rate measurement, baseline respiratory rate measurement, baseline blood pressure measurement, and other types of baseline biometric measurements. The one or more baseline measurements may be used for comparison with one or more parameter measurements captured throughout the interrogation procedure.

[0207] Additionally, the processing circuitry can output one or more prompts (1706) for obtaining information about the patient 105's baseline perception level and the baseline location of the sensory abnormality sensation. Furthermore, the processing circuitry can receive information indicating the patient 105's baseline perception level and baseline location. The baseline perception level may represent one or more sensations felt by the patient 105 before performing any action related to the inquiry procedure, and the baseline location may represent the location of the stimulus before performing any action related to the inquiry procedure. One or more prompts for obtaining information about the patient 105's baseline perception level may include prompts for obtaining the current state of the sensory abnormality delivered by the IMD 110. Prompts for obtaining the current state of the sensory abnormality may include a request for a proportional numerical rating, such as a stimulus intensity rating from 1 to 10. In some examples, a rating "1" represents a slight tingling sensation, a rating "5" represents a moderate pricking sensation, and a rating "10" represents a heavy thud. Alternatively or additionally, prompts for obtaining the current state of the sensory abnormality may include a request for the patient 105's baseline discomfort level, where "1" represents the minimum discomfort and "10" represents the maximum discomfort. The prompts used to obtain a baseline location may include a request to identify the location where the patient 105 felt the stimulus (e.g., the location of the body).

[0208] The processing circuitry triggers the IMD 110 to begin collecting one or more continuous measurements (1708). As mentioned herein, a “continuous measurement” can refer to a parameter measurement that is recorded so that changes in the corresponding parameter can be viewed over the time period during which the continuous measurement is performed. In other words, a continuous measurement can refer to a sample sequence of a corresponding parameter, wherein the sample sequence is collected by the IMD 110 at a certain sampling rate. In some examples, one or more continuous measurements may include continuous heart rate measurements, continuous blood pressure measurements, continuous respiratory measurements, continuous accelerometer measurements, continuous ECAP measurements, or any combination thereof. A continuous ECAP measurement can refer to a continuous sensing signal comprising one or more ECAPs, wherein the processing circuitry is configured to identify one or more ECAPs in the sensing signal.

[0209] The processing circuitry outputs an instruction (1710) to cause patient 105 to perform an action for display via a user interface. The action may include any one or more of a set of transient patient actions, such as coughing, arching the back, Valsalva maneuver, leg raising, or other types of movement. Transient patient actions may include any kind of movement that could cause one or more electrodes of lead 130 to move closer to or further away from the target tissue of patient 105. As an example, in response to the output instruction, user interface 356 may display the message “PLEASE COUGH ONCE”, instructing the patient to cough to perform a transient patient action, which may briefly change the distance between one or more electrodes of lead 130 and the target tissue of patient 105. In some examples, the processing circuitry may receive an indication of action completion from external programmer 300 or another device. For example, when the action is a cough, patient 105 may provide input to user interface 356 indicating that the cough is complete, and external programmer 300 may forward the patient input to the processing circuitry. In response to action completion, the processing circuitry triggers a halt to the collection of one or more continuous measurements (1712). In some examples, the processing circuitry may save one or more continuous measurements to memory for analysis.

[0210] An interrogation procedure may include a set of requests delivered sequentially and a set of responses, wherein the set of requests depends at least in part on the set of responses. The set of requests and the set of responses may be interleaved. For example, the processing circuitry may output a first request, receive a first response to the first request, output a second request based on the first response, receive a second response, and so on. Thus, the interrogation procedure can represent a logical flow that can be based on a set of responses received by the processing circuitry.

[0211] The processing circuitry can output a request to identify whether an undesirable attribute occurred during the execution of an action, for display on the user interface 356 (1714). For example, the processing circuitry can output a request including the message: “Are certain attributes of the abnormal sensation during the execution of the action undesirable? (Yes or No).” In this way, the request to identify whether an undesirable attribute occurred during the execution of an action can represent the first request in a set of requests that prompt the user to identify whether the action caused an undesirable attribute (e.g., an undesirable sensation). The processing circuitry can receive a response to the request from the external programmer 300 to identify whether an undesirable attribute occurred during the execution of the action (1716). In response to receiving a response indicating that an undesirable attribute occurred during the execution of the action (the “Yes” branch of box 1716), the processing circuitry can output one or more requests identifying the identifier of the undesirable attribute (1718). For example, the processing circuitry can output the message “Select undesirable abnormal sensation attributes during operation: too strong, pulsating, increased position, or none.”

[0212] One or more requests identifying the identifier of an undesirable attribute may include requests corresponding to each of a set of undesirable attributes (including, but not limited to, high intensity, pulsation, and increased or undesirable position). The processing circuitry outputs a request (1720) to obtain an indication of whether the intensity of the stimulus delivered by IMD 110 is uncomfortably high during the execution of the action. In response to receiving a response that the intensity of the stimulus is not uncomfortably high during the execution of the action (the "No" branch of box 1720), the processing circuitry outputs a request regarding whether the undesirable attribute indicates increased positional sensation (1722). In response to receiving a response that the undesirable attribute is not increased positional sensation (the "No" branch of box 1722), the processing circuitry outputs a request regarding whether the undesirable attribute indicates undesirable pulsation (1724). In response to receiving a response that the undesirable attribute is not a pulsating sensation (the "No" branch of box 1722), the processing circuitry can determine that the undesirable attribute is not any of the uncomfortable high intensity, increased location, or pulsating sensation, and the interrogation proceeds to box 1726, where the processing circuitry sets an indication to request the patient 105 to perform a "next" action different from the action corresponding to the current interrogation. The processing circuitry does not need to output three requests (boxes 1720, 1722, 1724), each representing one of the three sensations. Alternatively, in some cases, the processing circuitry may output a single request including a menu of sensations for the patient 105 to choose from.

[0213] In response to receiving a response that the stimulus intensity is uncomfortably high during the execution of an action (the "Yes" branch of box 1720), the processing circuit can output one or more requests (1728) identifying whether the uncomfortably high intensity occurs at the beginning of the action, at the end of the action, or throughout the entire duration of the action. Additionally, in response to receiving a response that the undesirable attribute is an increased sense of position (the "Yes" branch of box 1722), the processing circuit can output one or more requests (1730) identifying whether the uncomfortably increased sense of position occurs at the beginning of the action, at the end of the action, or throughout the entire duration of the action. In this way, the processing circuit can output prompts to obtain information about when the undesirable attribute occurs relative to the action in both cases where the undesirable attribute represents an uncomfortably high intensity and where the undesirable attribute represents an increased stimulus location.

[0214] The processing circuit outputs a request to identify whether the undesirable attribute appears at the beginning of the action execution (1732). In response to receiving a response indicating that the undesirable attribute did not appear at the beginning of the action execution (the "No" branch of box 1732), the processing circuit outputs a request to identify whether the undesirable attribute appears at the end of the action execution (1734). In response to receiving a response indicating that the undesirable attribute did not appear at the end of the action execution (the "No" branch of box 1734), the processing circuit determines that the undesirable attribute appeared throughout the entire action execution, and the processing circuit outputs a request to identify whether the overstimulation threshold of IMD 110 is currently higher than the expected overstimulation threshold (1736).

[0215] It may be helpful for the processing circuitry to determine whether the discomfort occurs at the beginning, end, throughout the entire action, or intermittently throughout the action. In this way, the processing circuitry can determine one or more control strategy changes to implement so that the patient does not experience discomfort when the same action is performed again. Figures 17A to 17B The same undesirable attributes felt during the inquiry process.

[0216] In response to receiving a response indicating that an undesirable attribute appears at the beginning of an action (the "Yes" branch of box 1732), the processing circuitry may generate a recommendation (1738) to increase the decrement step size of one or more stimulation pulses delivered by IMD 110. In response to receiving a response indicating that an undesirable attribute appears at the end of an action (the "Yes" branch of box 1734), the processing circuitry may generate a recommendation (1740) to decrease the increment step size of one or more stimulation pulses delivered by IMD 110. The processing circuitry prompts the patient 105 to perform an action that may represent a transient patient action, which moves one or more electrodes of lead 130 closer to the target tissue of the patient 105, causing IMD 110 to decrement the amplitude of the stimulation pulse delivered to the target tissue at the beginning of the transient patient action and to increment the amplitude of the stimulation pulse delivered to the target tissue at the end of the transient patient action.

[0217] When the processing circuit receives an indication that discomfort has occurred at the start of an action, it may be beneficial for the processing circuit to recommend increasing the decrement step size of the stimulation pulse delivered by the IMD 110, such that if the recommendation is implemented, the stimulation pulse decreases at a faster rate compared to the time prior to the processing circuit's recommendation. Conversely, when the processing circuit receives an indication that discomfort has occurred at the end of an action, it may be beneficial for the processing circuit to recommend decreasing the increment step size of the stimulation pulse delivered by the IMD 110, such that if the recommendation is implemented, the stimulation pulse increases at a slower rate compared to the time prior to the processing circuit's recommendation. When implemented, such recommendations from the processing circuit can reduce the likelihood that the patient 105 will experience uncomfortable stimulation (e.g., transient overstimulation) when performing the same action prompted by the processing circuit as part of an interrogation in the future.

[0218] When the processing circuit receives an indication that the overstimulation threshold is currently higher than the desired overstimulation threshold (the "Yes" branch of box 1736), the processing circuit can generate a recommendation to reduce the overstimulation threshold. When the processing circuit receives an indication that the overstimulation threshold is currently not higher than the desired overstimulation threshold (the "No" branch of box 1736), the processing circuit can generate a recommendation (1744) to reduce the lower limit boundary of the buffer for one or more stimulation pulses delivered by the IMD 110. The buffer may represent the range of ECAP amplitude that the IMD 110 maintains for the stimulation element to remain constant. Thus, by reducing the lower limit boundary of the buffer, the IMD 110 can reduce the threshold used to increase the stimulation amplitude.

[0219] When the processing circuit receives a response indicating an undesirable pulsation (the "Yes" branch of box 1724), it can determine whether the rate of increase (e.g., increment step size) of one or more stimulus pulses delivered by the IMD 110 is greater than an ideal rate of increase value. When the processing circuit determines that the rate of increase is greater than the desired rate of increase value (the "Yes" branch of box 1746), it can generate a recommendation to reduce the rate of increase (1748). When the processing circuit determines that the rate of increase is not greater than the desired rate of increase value (the "No" branch of box 1746), it can generate a recommendation to increase the size of the hysteresis band to allow the IMD 110 to deliver more stimulus pulses (1750).

[0220] In response to generating a recommendation to increase the deceleration rate (e.g., deceleration step size) of one or more stimulation pulses delivered by IMD 110, to decrease the increase rate of the acceleration rate of one or more stimulation pulses delivered by IMD 110, to lower the overstimulation threshold, to increase the buffer size, or to decrease the lower boundary of the buffer, the processing circuitry can set an indication to prompt the patient 105 to repeat the same action prompted by the processing circuitry during the current interrogation (1752). This allows for repetition. Figures 17A to 17B The inquiry operation prompts the processing circuit to prompt the patient 105 to perform the same action again and allows the processing circuit to re-evaluate the same action.

[0221] When the processing circuit receives a response indicating that no undesirable attribute occurred during the execution of an action in response to a request to identify whether an undesirable attribute occurred during the execution of the action (the "No" branch of box 1716), the processing circuit may output a request to obtain information about whether an undesirable attribute occurred after the execution of the action (1754), and the processing circuit may receive a response to the request (1756). When the response indicates that no undesirable attribute occurred after the execution of the action (the "No" branch of box 1756), the processing circuit may determine whether to repeat the query operation. When the response indicates that an undesirable attribute did occur after the execution of the action (the "Yes" branch of box 1756), the processing circuit may output a request to obtain information about the identifier of the undesirable attribute that occurred after the execution of the action for display on the user interface (1758). For example, the processing circuit may output the message: "Select undesirable sensory abnormality attribute after the action: too strong, temporary loss of sensory abnormality, none," for display on the user interface. The processing circuit may receive a response that the stimulus intensity is uncomfortably high (1760). In this case, the processing circuit generates a recommendation to reduce the maximum stimulus amplitude (1764). The processing circuitry can receive a response indicating a temporary loss of sensation due to discomfort (1762). In this case, the processing circuitry generates a recommendation to increase the step size of one or more stimulus pulses generated by the IMD 110 (1766).

[0222] If the processing circuitry determines that the undesirable attribute following the sensation is neither related to high intensity nor to temporary loss of sensation, the inquiry operation can proceed to box 1726, and the processing circuitry can set an instruction to perform the next action. In response to the recommendations in generating boxes 1764 and 1766, the processing circuitry can set an instruction (1752) to prompt the patient 105 to repeat the same action prompted by the processing circuitry during the current inquiry operation. At box 1772, the processing circuitry can determine whether to restart the inquiry operation by generating a request for the patient 105 to perform an action or to end the procedure.

[0223] Figure 18 This is a flowchart illustrating an example of storing one or more histogram datasets, based on one or more techniques disclosed herein. About Figure 1 IMD 110 and external programmer 150, Figure 2 IMD 200 and Figure 3 The external programmer 300 is described Figure 18 .However, Figure 18 The technology can be performed by different components of IMD 110, external programmer 150, IMD 200 and external programmer 300, or by additional or alternative medical devices.

[0224] When estimating tissue activation using evoked compound action potentials (ECAPs) as input during the delivery of electrical current to the nervous system (e.g., the spinal cord), it is necessary to record physiological signals and properties of the delivery system, which are then correlated with the patient's perception of treatment and / or therapeutic efficacy. If too much tissue is activated, the patient may experience a sharp increase in sensory abnormalities or similar unwanted side effects perceived from or received by the stimulation delivered by the IMD110. If too little tissue is activated, the patient may lose the therapeutic benefit and experience symptom relapse. Control strategies executed by the IMD110 measure tissue activation and adjust the stimulation based on the amount of activated tissue.

[0225] During the configuration and tuning of the control strategy executed by the IMD 110, measurements of one or more characteristics can be used to allow for continuous refinement of the control strategy, including characteristics such as: patient input of the intensity of the undesirable attribute, various ECAP features when the undesirable attribute is present, stimulus amplitude when the undesirable attribute is present, response time of the control strategy when the undesirable attribute is present, and background symptom level. Data should be collected throughout the day, even if the patient does not perceive any unwanted side effects. For example, the control strategy may be overly sensitive to potential undesirable attributes, thus reducing the delivered stimulus amplitude, leading to symptom relapse and / or loss of sensory abnormalities. In these cases, the system may respond prematurely to measured biomarkers that do not accurately indicate potential undesirable attributes. This data is used to evaluate the effectiveness of ECAP stimulus control in improving pain management and patient comfort. This requires evaluation relative to the optimization of system parameters.

[0226] This disclosure describes one or more techniques for addressing the need to collect the properties described above using a limited amount of memory located on the IMD 110. For example, it may not be possible to continuously collect and store histogram data in memory for days or weeks. Thus, the IMD 110 can periodically collect histogram data over a period of time within the limitations of its memory. The duration and resolution of the histograms generated by the IMD 110 can be configurable.

[0227] The IMD 110 can collect multiple sets of periodic histogram data for one or more attributes from a set of properties in the background. This set of properties may include stimulus amplitude, ECAP characteristic amplitude, the time duration of each control strategy state, and motion signal amplitude. In some examples, each histogram dataset may correspond to a specific time window. In some examples, the duration of the time window may range from 3 to 10 minutes (e.g., 5 minutes), but this is not required. In some examples, the duration of the histogram's time window may be greater than 10 minutes or less than 3 minutes. Because the range of attribute amplitudes varies for each patient, the "divider" of the histogram bins is configurable.

[0228] The IMD 110 can also collect histogram data from a rolling buffer (the shorter the duration of each histogram, the higher the overall temporal resolution of the recording). The histogram buffer is not saved to the recording memory until an external indication is received from the patient indicating that an unwanted attribute has been experienced. The idea is that a 3-minute buffer will have a sufficiently long duration to capture the characteristics of unwanted attributes that occur before the patient triggers the event. When an unwanted attribute is experienced, the patient needs time to retrieve the patient programmer, activate the programmer, and send the trigger.

[0229] Other external events may be related to physiological conditions, such as when a patient starts and stops activity (e.g., walking, sleeping) and when a patient adjusts some parameters of the system (e.g., control strategy thresholds). These events are recorded as timestamps, which can then be indexed into a periodic histogram during post-processing.

[0230] In some examples, patient 105 may respond to experiencing an unwanted attribute retrieval by external programmer 150 (1802). External programmer 150 receives user input indicating an unwanted attribute (e.g., “sensory dullness”) (1804). Additionally, in some cases, external programmer 150 may receive data indicating the cause and intensity of the unwanted attribute. External programmer 150 records the intensity and cause of the unwanted attribute in storage device 354 (1806).

[0231] In response to receiving user input indicating an unwanted attribute, external programmer 150 sends an event trigger (1808) to IMD 110, wherein the event trigger indicates the user identifier of the unwanted attribute. IMD 110 may store histogram data (1810) in a rolling buffer of IMD 110. For example, the histogram data stored in the rolling buffer when IMD 110 receives the event trigger may include histogram data 1812. To permanently store histogram data 1812, IMD 110 may permanently store histogram data 1812 in the memory of IMD 110. The permanently stored histogram data may include histogram data 1816.

[0232] In some cases, the IMD 110 can periodically and permanently store multiple histogram datasets. For example, histogram datasets 1818, 1820, 1850, 1852, and 1854 can represent histogram datasets periodically stored by the IMD 110. In some examples, the IMD 110 can automatically store histogram datasets according to a predetermined frequency (e.g., hourly, daily). These automatically recorded histogram datasets can each correspond to a time window with a predetermined length (e.g., 5 minutes).

[0233] In some examples, IMD 110 may also permanently store information corresponding to the event indicated by patient 105 (e.g., event type and timestamp). For example, external programmer 150 may receive user input indicating the start of the event (1822). Additionally, external programmer 150 may also receive information indicating an event description. External programmer 150 records the information indicating the event description in memory (1824). External programmer 150 sends a message to IMD 110 indicating a first timestamp marking the start of the event (1826). IMD 110 saves the first timestamp marking the start of the event and saves the event type (1828). Information including the first timestamp and type is saved as information 1830 to the memory of IMD 110. External programmer 150 may receive user input indicating the end of the event (1832). External programmer 150 sends a message to IMD 110 indicating a second timestamp marking the end of the event (1834). IMD 110 saves the second timestamp marking the end of the event (1836). The second timestamp, 1838, marks the end of the event in the IMD 110 memory.

[0234] The first and second timestamps can be applied during the analysis of histogram data automatically captured by the IMD 110. For example, the processing circuitry can identify the first histogram data collected by the IMD 110 that is closest to the first timestamp, and the processing circuitry can identify the second histogram data collected by the IMD 110 that is closest to the second timestamp. In some cases, the processing circuitry can identify one or more additional histogram datasets that appear between the first and second histogram datasets (e.g., during an event). The first histogram data may indicate one or more conditions at the start of the event, and the second histogram data may indicate one or more conditions at the end of the event. The processing circuitry can analyze the first and second histogram data to determine whether any of the one or more conditions have changed from the start of the event to the end of the event. Based on this analysis, the processing circuitry can determine whether one or more changes to the control strategy of the IMD 110 are recommended. Additionally, the description of the event can be applied during the analysis of the histogram data automatically captured by the IMD 110. Histogram data collected by IMD 110 during or near an event can be analyzed to be associated with the event, enabling processing circuitry to identify one or more trends associated with the event.

[0235] The processing circuitry can record one or more timestamps corresponding to parameter changes initiated by the external programmer 150. For each instance where the external programmer 150 initiates a change in one or more parameters defining a stimulus delivered by the IMD 110, the processing circuitry can record a timestamp corresponding to the parameter change. For example, the external programmer 150 can receive a user's selection of a new parameter (1840). The external programmer 150 initiates a change to the new parameter (1842) and records a timestamp corresponding to the change (1846). The timestamp can be saved as information 1848 to the memory of the IMD 110 and / or the memory of the external programmer 150.

[0236] The timestamp indicating a parameter change can be applied during the analysis of histogram data automatically captured by IMD 110. For example, histogram data 1852 is collected by IMD 110 close to the timestamp indicating a parameter change (e.g., information 1848). Additionally, histogram data 1850 and histogram data 1854 are collected by IMD 110 before the timestamp indicating a parameter change. Thus, the processing circuitry can analyze histogram data 1850, 1852, and 1854 to determine the impact of the parameter change on one or more aspects of the histogram data (e.g., the size of one or more bins). In some examples, based on this analysis, the processing circuitry can generate recommendations for changing the control strategy of IMD 110. In some examples, based on this analysis, the processing circuitry can generate recommendations for maintaining the control strategy of IMD 110 in its current state.

[0237] Figure 19 A graph 1900 illustrates the ECAP amplitude of a set of ECAPs sensed by the IMD 110 over an 11-second time period associated with a transient overstimulation event, according to one or more techniques disclosed herein. In some examples, the IMD 110 records the ECAP at a frequency of 50 Hz. As shown in graph 1900, the ECAP amplitude is maximum during the 6th–8th second of the plot. This increase in ECAP amplitude may indicate that the patient experienced a sensory attribute of discomfort. Figure 19 As shown, each one-second window of graph 1900 includes a set of data points, where each data point represents the magnitude of the ECAP measured by the IMD 110 at the time corresponding to the position of the corresponding data point on the x-axis of graph 1900. The magnitude of the measured ECAP varies within the corresponding one-second window, and this variation can be seen in the histogram data corresponding to the data points shown in graph 1900.

[0238] Figure 20 This disclosure illustrates one or more techniques including those related to... Figure 19 The curve graph of 1900 corresponds to a set of histograms of histogram data for 2000. For example... Figure 20 As shown, graph 2000 includes a set of histograms 2010-2030. Although the set of histograms shown in graph 2000 includes 11 histograms (e.g., one histogram corresponds to each second of a total of 11 seconds of events), a histogram dataset representing 11 seconds can include more or fewer than 11 histograms. For example, in other examples, histogram data could include 3 minutes of one-second histograms, i.e., 180 one-second histograms. However, in other examples, each time "bin" of the corresponding histogram can be shorter or longer than 1 second. Figure 20As shown in the examples, histograms 2020, 2022, and 2024 indicate that the 6–8 sec interval includes more high-amplitude ECAPs than other histograms (such as histogram 2010). This may indicate that patient 105 experienced transient overstimulation during the 6–8 sec interval, as well as the amplitude of those sensed ECAPs.

[0239] The following examples are sample systems, devices, and methods described in this article.

[0240] Example 1: A system comprising: a user interface; and processing circuitry configured to: output a message requesting a patient to perform a set of actions for display by the user interface; receive user input from the user interface indicating a patient response associated with the set of actions; and, based on the user input, determine one or more adjustments to a control strategy, the control strategy controlling electrical stimulation delivered by the medical device based on at least one evoked compound action potential (ECAP) sensed by the medical device.

[0241] Example 2: The system as described in Example 1, wherein the system further includes: a communication circuit configured to communicate with the medical device, wherein the processing circuit is configured to output instructions to the medical device via the communication circuit for configuring the one or more adjustments to the control strategy.

[0242] Example 3: A system as described in any one of Examples 1 to 2, wherein the electrical stimulation includes a plurality of notification pulses and a plurality of control pulses, each of the plurality of control pulses triggering a corresponding ECAP among the plurality of ECAPs, wherein the control strategy controls one or more parameters corresponding to the plurality of control pulses delivered by the medical device based on the plurality of ECAPs, and wherein the control strategy controls one or more parameters corresponding to the plurality of notification pulses delivered by the medical device based on the plurality of ECAPs.

[0243] Example 4: A system as described in any one of Examples 1 to 3, wherein the control strategy controls one or more parameters of the electrical stimulation therapy delivered by the medical device, wherein the electrical stimulation therapy comprises a plurality of stimulation pulses, and wherein, in order to determine the one or more adjustments to the control strategy, the processing circuitry is configured to: determine the one or more adjustments to cause the control strategy to perform any one or a combination of the following: decreasing the decrement step size or decrement step rate of the plurality of stimulation pulses in response to one or more events associated with the patient response; increasing the decrement step size or decrement step rate of the plurality of stimulation pulses in response to the one or more events associated with the patient response; decreasing the increment step size or increment step rate of the plurality of stimulation pulses in response to the one or more events associated with the patient response; and increasing the increment step size or increment step rate of the plurality of stimulation pulses in response to one or more transient events associated with the patient response.

[0244] Example 5: A system as described in any one of Examples 1 to 4, wherein the processing circuitry is further configured to: output a set of requests for display on the user interface, wherein each of the set of requests includes a prompt for obtaining information relating to one or more patient sensations corresponding to the action, and wherein, in order to receive the user input instructing the patient to respond, the processing circuitry is configured to: receive a set of responses from the user interface, wherein each of the set of responses represents a patient response to a corresponding request in the set of requests.

[0245] Example 6: A system as described in any one of Examples 1 to 5, wherein the processing circuitry is configured to: output a first request from the set of requests for display on the user interface, wherein the first request includes a prompt that causes the user to indicate whether the set of actions caused an undesirable sensation during the set of actions; and receive a first response from the user interface from the set of responses, wherein the first response includes a patient response that the set of actions caused an undesirable sensation during the set of actions or a patient response that the set of actions did not cause an undesirable sensation during the set of actions.

[0246] Example 7: A system as described in any one of Examples 1 to 6, wherein, in response to receiving a patient response that the set of actions causes an undesirable sensation during the set of actions, the processing circuitry is configured to: output a second set of requests from the set of requests for display on the user interface, wherein the second set of requests includes a prompt instructing the user to identify the undesirable sensation from a menu of possible undesirable sensations; receive a second set of responses from the set of responses from the user interface, wherein the second set of responses includes the user's identification of the undesirable sensation from the menu of possible undesirable sensations; and determine the one or more adjustments to the control strategy based on the second set of responses.

[0247] Example 8: A system as described in any one of Examples 1 to 7, wherein, in response to receiving a patient response that the set of actions did not cause an undesirable sensation during the set of actions, the processing circuitry is configured to: output a second request from the set of requests for display on the user interface, wherein the second request includes a prompt causing the user to indicate whether the set of actions caused an undesirable sensation after the set of actions; and receive a second response from the user interface, wherein the second response includes a patient response that the set of actions caused an undesirable sensation after the set of actions or a patient response that the set of actions did not cause an undesirable sensation after the set of actions.

[0248] Example 9: A system as described in any one of Examples 1 to 8, wherein, in response to receiving a patient response that the set of actions causes an undesirable sensation after the set of actions, the processing circuitry is configured to: output a third set of requests from the set of requests for display on the user interface, wherein the third set of requests includes a prompt that enables the user to identify the undesirable sensation from a menu of possible undesirable sensations; receive a third set of responses from the set of responses from the user interface, wherein the third set of responses includes the user's identification of the undesirable sensation from the menu of undesirable sensations; and determine the one or more adjustments to the control strategy based on the third set of responses.

[0249] Example 10: A system as described in any one of Examples 1 to 9, wherein the set of actions is a first set of actions, wherein the message is a first message, and wherein, in response to receiving a patient response that the first set of actions does not elicit an undesirable sensation after the first set of actions, the processing circuitry is configured to: determine whether to prompt the patient to perform a second set of actions; and in response to determining that the patient is prompted to perform a second set of actions, output a second message to be displayed by the user interface, the second message requesting the patient to perform the second set of actions.

[0250] Example 11: The system of any one of Examples 1 to 10, wherein the processing circuitry is further configured to: output an instruction to cause the medical device to measure one or more parameters before outputting a message requesting the patient to perform the set of actions; and receive data from the medical device indicating the one or more measurement parameters, wherein the data corresponds to a time period including the period during which the patient performs the set of actions.

[0251] Example 12: A system as described in any one of Examples 1 to 11, wherein the one or more parameters include any one or a combination of the following: the amplitude of one or more stimulation pulses of the electrical stimulation therapy, the characteristics of the evoked compound action potential (ECAP) in response to the one or more stimulation pulses, the patient's electrocardiogram (EGM), the patient's exercise level, or any combination thereof.

[0252] Example 13: A system as described in any one of Examples 1 to 12, wherein the medical device includes an implantable medical device (IMD).

[0253] Example 14: A system as described in any one of Examples 1 to 13, wherein the external device includes the user interface.

[0254] Example 15: A method comprising: outputting a message requesting a patient to perform a set of actions by a processing circuit for display by the user interface; receiving user input from the user interface by the processing circuit indicative of a patient response associated with the set of actions; and determining, based on the user input, one or more adjustments to a control strategy, the control strategy controlling electrical stimulation delivered by the medical device based on at least one evoked compound action potential (ECAP) sensed by the medical device.

[0255] Example 16: The method of Example 15 further includes: the processing circuit outputting instructions via a communication circuit to the medical device for configuring the one or more adjustments to the control strategy.

[0256] Example 17: A method as described in any one of Examples 15 to 16, wherein the control strategy controls one or more parameters of the electrical stimulation therapy delivered by the medical device, wherein the electrical stimulation therapy comprises a plurality of stimulation pulses, and wherein determining the one or more adjustments to the control strategy comprises: determining the one or more adjustments to cause the control strategy to perform any one or a combination of: decreasing the decrement step size or decrement step rate of the plurality of stimulation pulses in response to one or more events associated with the patient response; increasing the decrement step size or decrement step rate of the plurality of stimulation pulses in response to the one or more events associated with the patient response; decreasing the increment step size or increment step rate of the plurality of stimulation pulses in response to the one or more events associated with the patient response; and increasing the increment step size or increment step rate of the plurality of stimulation pulses in response to one or more transient events associated with the patient response.

[0257] Example 18: The method of any one of Examples 15 to 17, wherein the method further comprises: outputting a set of requests by the processing circuit for display by the user interface, wherein each of the set of requests includes a prompt for obtaining information relating to one or more patient sensations corresponding to the action, and wherein receiving the user input instructing the patient to respond comprises: receiving a set of responses from the user interface, wherein each of the set of responses represents a patient response to a corresponding request in the set of requests.

[0258] Example 19: The method of any one of Examples 15 to 18, wherein the method further comprises: outputting a first request from the set of requests by the processing circuit for display by the user interface, wherein the first request includes prompting the user to indicate whether the set of actions caused an undesirable sensation during the set of actions; and receiving a first response from the set of responses by the processing circuit from the user interface, wherein the first response includes a patient response in which the set of actions caused an undesirable sensation during the set of actions or a patient response in which the set of actions did not cause an undesirable sensation during the set of actions.

[0259] Example 20: A method as described in any one of Examples 15 to 19, wherein, in response to receiving a patient response that the set of actions causes an undesirable sensation during the set of actions, the method further comprises: outputting a second set of requests from the set of requests to the user interface for display, wherein the second set of requests includes a prompt instructing the user to identify the undesirable sensation from a menu of possible undesirable sensations; receiving a second set of responses from the user interface, wherein the second set of responses includes the user's identification of the undesirable sensation from the menu of undesirable sensations; and determining, based on the second set of responses, one or more adjustments to the control strategy.

[0260] Example 21: The method of any one of Examples 15 to 20, wherein, in response to receiving a patient response that the set of actions did not cause an undesirable sensation during the set of actions, the method further comprises: outputting a second request from the set of requests by the processing circuit for display by the user interface, wherein the second request includes prompting the user to indicate whether the set of actions caused an undesirable sensation after the set of actions; and receiving a second response from the set of responses by the processing circuit, wherein the second response includes a patient response that the set of actions caused an undesirable sensation after the set of actions or a patient response that the set of actions did not cause an undesirable sensation after the set of actions.

[0261] Example 22: The method of any one of Examples 15 to 21, wherein, in response to receiving a patient response that causes an undesirable sensation after the set of actions, the method further comprises: outputting a third set of requests from the set of requests to the user interface for display, wherein the third set of requests includes a prompt instructing the user to identify the undesirable sensation from a menu of possible undesirable sensations; receiving a third set of responses from the user interface, wherein the third set of responses includes the user's identification of the undesirable sensation from the menu of undesirable sensations; and determining, based on the third set of responses, one or more adjustments to the control strategy.

[0262] Example 23: The method of any one of Examples 15 to 22, wherein the set of actions is a first set of actions, wherein the message is a first message, and wherein, in response to receiving a patient response that the first set of actions does not cause an undesirable sensation after the first set of actions, the method further includes: determining by the processing circuit whether to prompt the patient to perform a second set of actions; and in response to determining that the patient is prompted to perform a second set of actions, the processing circuit outputs a second message to be displayed by the user interface, the second message requesting the patient to perform the second set of actions.

[0263] Example 24: The method of any one of Examples 15 to 23 further includes: before outputting a message requesting the patient to perform the set of actions, the processing circuit outputs an instruction to cause the medical device to measure one or more parameters; and the processing circuit receives data from the medical device indicating the one or more measurement parameters, wherein the data corresponds to a time period including the period during which the patient performs the set of actions.

[0264] Example 25: A computer-readable medium including instructions that, when executed by a processor, cause the processor to: output a message requesting a patient to perform a set of actions for display by a user interface; receive user input from the user interface indicating a patient response associated with the set of actions; and, based on the user input, determine one or more adjustments to a control strategy, the control strategy controlling electrical stimulation delivered by the medical device based on at least one evoked compound action potential (ECAP) sensed by the medical device.

[0265] Example 26: A medical device comprising: a stimulation generating circuit configured to deliver electrical stimulation to a patient, wherein the electrical stimulation therapy includes a plurality of stimulation pulses; a sensing circuit configured to sense one or more evoked compound action potentials (ECAPs), wherein the sensing circuit is configured to sense each of the one or more ECAPs evoked by a corresponding stimulation pulse of the plurality of stimulation pulses; and a processing circuit configured to store a histogram dataset corresponding to a set of ECAPs of the plurality of ECAPs, the set of ECAPs being sensed by the sensing circuit within a time window.

[0266] Example 27: A medical device as described in Example 26, wherein the histogram dataset comprises a set of histogram bins, wherein each histogram bin in the set corresponds to a range of ECAP parameter values, and wherein each histogram bin in the set comprises a number of ECAPs associated with parameter values ​​within a corresponding range of ECAP parameter values ​​in the set of ECAPs.

[0267] Example 28: A medical device as described in any one of Examples 26 to 27, wherein the processing circuitry is further configured to: receive information instructing a patient response; and, in response to receiving user input instructing the patient response, capture the histogram dataset in a memory, wherein the histogram dataset includes data representing the patient response.

[0268] Example 29: A medical device as described in any one of Examples 26 to 28, wherein, in order to store the histogram dataset, the processing circuitry is configured to temporarily store the histogram dataset in a rolling buffer that is updated over time.

[0269] Example 30: A medical device as described in any one of Examples 26 to 29, wherein the processing circuitry is configured to capture a histogram dataset stored in the rolling buffer at the time when the processing circuitry receives user input indicating the patient's response, wherein the time window extends from a first time to a second time representing either the time when the processing circuitry receives the user input or a time after the processing circuitry receives the user input, and wherein the time window includes the time period during which the patient's response occurs.

[0270] Example 31: A medical device as described in any one of Examples 26 to 30, wherein the processing circuitry is configured to capture a histogram dataset stored in the rolling buffer after the time when the processing circuitry receives user input indicating the patient's response, wherein the time window extends from a first time to a second time representing the time after the processing circuitry receives the user input, and wherein the time window includes the time period during which the patient's response occurs.

[0271] Example 32: A medical device as described in any one of Examples 26 to 31, wherein the processing circuitry is configured to: receive a user request for setting one or more histogram parameters to collect the histogram dataset; and set the one or more histogram parameters based on the user request, wherein the one or more histogram parameters include a set of parameter ranges, the parameter ranges defining one or more histogram bins included in a set of histogram bins of the histogram data.

[0272] Example 33: A medical device as described in any one of Examples 26 to 32, wherein the histogram dataset comprises: a first histogram corresponding to the amplitude values ​​of a set of stimulus pulses delivered by the stimulus generation circuit; and a second histogram corresponding to the amplitude values ​​of the ECAP sensed by the sensing circuit in response to a set of stimulus pulses delivered by the stimulus generation circuit.

[0273] Example 34: A medical device as described in any one of Examples 26 to 33, wherein the time window is a first time window, wherein the histogram dataset includes a first histogram dataset, and wherein the processing circuitry is further configured to: store a plurality of second histogram datasets, wherein each of the plurality of second histogram datasets corresponds to one or more ECAPs sensed by the sensing circuitry within a second time window of the plurality of second time windows; and capture each of the plurality of second histogram datasets into a memory.

[0274] Example 35: A medical device as described in any one of Examples 26 to 34, wherein the processing circuitry is configured to: receive a user report of the start of a patient activity; save a first timestamp corresponding to the start of the patient activity; receive a user report of the end of the patient activity; and save a second timestamp corresponding to the end of the patient activity, wherein the first timestamp corresponds to one of the plurality of second histogram datasets and the second timestamp corresponds to one of the plurality of second histogram datasets.

[0275] Example 36: A method comprising: delivering electrical stimulation to a patient by a stimulation generation circuit, wherein the electrical stimulation treatment includes a plurality of stimulation pulses; sensing one or more evoked compound action potentials (ECAPs) by a sensing circuit, wherein the sensing circuit is configured to sense each of the one or more ECAPs evoked by a corresponding stimulation pulse of the plurality of stimulation pulses; and storing by a processing circuit a histogram dataset corresponding to a set of ECAPs of the plurality of ECAPs, the set of ECAPs being sensed by the sensing circuit within a time window.

[0276] Example 37: The method as described in Example 36, wherein the histogram dataset comprises a set of histogram bins, wherein each histogram bin in the set corresponds to a range of ECAP parameter values, and wherein each histogram bin in the set comprises a number of ECAPs associated with parameter values ​​within a corresponding range of ECAP parameter values ​​in the set of ECAPs.

[0277] Example 38: The method of any one of Examples 36 to 37, wherein the method further comprises: receiving information indicating a patient response by the processing circuit; and capturing the histogram dataset in a memory by the processing circuit in response to receiving user input indicating the patient response, wherein the histogram dataset includes data representing the patient response.

[0278] Example 39: The method of any one of Examples 36 to 38, wherein storing the histogram dataset includes temporarily storing the histogram dataset in a rolling buffer that is updated over time.

[0279] Example 40: The method of any one of Examples 36 to 39, wherein the method further comprises: capturing a histogram dataset stored in the rolling buffer by the processing circuit at the time when the processing circuit receives user input indicating the patient response, wherein the time window extends from a first time to a second time representing the time when the processing circuit receives the user input or a time after the processing circuit receives the user input, and wherein the time window includes the time period during which the patient response occurs.

[0280] Example 41: The method of any one of Examples 36 to 40, wherein the method further comprises: capturing a histogram dataset stored in the rolling buffer by the processing circuit at a time after the processing circuit receives user input indicating the patient's response, wherein the time window extends from a first time to a second time representing the time after the processing circuit receives the user input, and wherein the time window includes the time period during which the patient's response occurs.

[0281] Example 42: The method of any one of Examples 36 to 41, wherein the method further comprises: receiving a user request by the processing circuit for setting one or more histogram parameters to collect the histogram dataset; and setting the one or more histogram parameters by the processing circuit based on the user request, wherein the one or more histogram parameters include a set of parameter ranges, the parameter ranges defining one or more histogram bins included in a set of histogram bins of the histogram data.

[0282] Example 43: The method of any one of Examples 36 to 42, wherein the time window is a first time window, wherein the histogram dataset includes a first histogram dataset, and wherein the method further comprises: storing a plurality of second histogram datasets by the processing circuitry, wherein each of the plurality of second histogram datasets corresponds to one or more ECAPs sensed by the sensing circuitry within a second time window of a plurality of second time windows; and capturing each of the plurality of second histogram datasets into a memory by the processing circuitry.

[0283] Example 44: The method as described in any one of Examples 36 to 43, wherein the method further comprises: receiving a user report of the start of patient activity by the processing circuit; storing a first timestamp corresponding to the start of the patient activity by the processing circuit; receiving a user report of the end of the patient activity by the processing circuit; and storing a second timestamp corresponding to the end of the patient activity by the processing circuit, wherein the first timestamp corresponds to one of the plurality of second histogram datasets and the second timestamp corresponds to one of the plurality of second histogram datasets.

[0284] Example 45: A computer-readable medium comprising instructions that, when executed by a processor, cause the processor to: deliver electrical stimulation to a patient, wherein the electrical stimulation treatment comprises a plurality of stimulation pulses; sense one or more evoked compound action potentials (ECAPs), wherein the sensing circuitry is configured to sense each of the one or more ECAPs evoked by a corresponding stimulation pulse among the plurality of stimulation pulses; and store a histogram dataset corresponding to a set of ECAPs among the plurality of ECAPs, the set of ECAPs being sensed by the sensing circuitry within a time window.

[0285] The techniques described in this disclosure can be implemented, at least in part, in hardware, software, firmware, or any combination thereof. For example, aspects of the techniques can be implemented in one or more microprocessors, DSPs, ASICs, FPGAs, or any other equivalent integrated or discrete logic QRS circuitry, and any combination of such components (embodied in external devices such as physician or patient programmers, stimulators, or other devices). The terms “processor” and “processing circuitry” can generally refer to any of the aforementioned logic circuitry, alone or in combination with other logic circuitry, or any other equivalent circuitry, alone or in combination with other digital or analog circuitry.

[0286] For aspects implemented in software, at least some of the functions attributable to the systems and devices described in this disclosure may be embodied as instructions on a computer-readable storage medium (such as RAM, DRAM, SRAM, FRAM, disk, optical disk, flash memory, or EPROM or EEPROM). These instructions may be executed to support one or more aspects of the functions described in this disclosure.

[0287] Furthermore, in some aspects, the functionality described herein can be provided within dedicated hardware and / or software modules. Describing different features as modules or units is intended to highlight functional differences and does not imply that such modules or units must be implemented by different hardware or software components. Rather, the functionality associated with one or more modules or units can be performed by different hardware or software components, or integrated within common or different hardware or software components. Moreover, these techniques can be implemented entirely within one or more circuit or logic elements. The techniques disclosed herein can be implemented in a wide range of devices or apparatuses, including IMDs, external programmers, combinations of IMDs and external programmers, integrated circuits (ICs) or a set of ICs, and / or discrete circuits residing in IMDs and / or external programmers.

Claims

1. A system for controlling electrical stimulation therapy, the system comprising: user interface; as well as Processing circuit, the processing circuit being configured to: Output a message requesting the patient to perform a set of actions for display on the user interface; Receive user input from the user interface, the user input indicating a patient response associated with the set of actions; as well as Based on the user input, one or more adjustments to a control strategy are determined, the control strategy controlling electrical stimulation delivered by the medical device based on at least one evoked compound action potential (ECAP) sensed by the medical device.

2. The system as claimed in claim 1, wherein, The system further includes: A communication circuit configured to communicate with the medical device. The processing circuit is configured to output instructions to the medical device via the communication circuit for configuring one or more adjustments to the control strategy.

3. The system as described in claim 1, in, The electrical stimulation includes multiple notification pulses and multiple control pulses, each of the multiple control pulses triggering a corresponding ECAP among the multiple ECAPs. The control strategy, based on the plurality of ECAPs, controls one or more parameters corresponding to the plurality of control pulses delivered by the medical device. The control strategy controls one or more parameters corresponding to the plurality of notification pulses delivered by the medical device, based on the plurality of ECAPs.

4. The system as claimed in claim 1, wherein, The control strategy controls one or more parameters of the electrical stimulation therapy delivered by the medical device, wherein the electrical stimulation therapy comprises a plurality of stimulation pulses, and wherein, in order to determine the one or more adjustments to the control strategy, the processing circuitry is configured to: The one or more adjustments are determined to cause the control strategy to perform any one or a combination of the following: decreasing the decrement step size or decrement step rate of the plurality of stimulation pulses in response to one or more events associated with the patient response; increasing the decrement step size or decrement step rate of the plurality of stimulation pulses in response to the one or more events associated with the patient response; decreasing the increment step size or increment step rate of the plurality of stimulation pulses in response to the one or more events associated with the patient response; and increasing the increment step size or increment step rate of the plurality of stimulation pulses in response to one or more transient events associated with the patient response.

5. The system as claimed in claim 1, wherein, The processing circuit is further configured to: A set of requests is output for display on the user interface, wherein each request includes a prompt for obtaining information relating to one or more patient sensations corresponding to the action, and wherein, in order to receive user input instructing the patient to respond, the processing circuitry is configured to: A set of responses is received from the user interface, wherein each response in the set represents a patient's response to a corresponding request in the set of requests.

6. The system of claim 5, wherein, The processing circuit is configured as follows: Output the first request in the group of requests for display on the user interface, wherein the first request includes a prompt for the user to indicate whether the group of actions caused an unpleasant sensation during the group of actions; and Receive a first response from the group of responses from the user interface, wherein the first response includes a patient response in which the group of actions causes an undesirable sensation during the group of actions or a patient response in which the group of actions does not cause an undesirable sensation during the group of actions.

7. The system of claim 6, wherein, In response to receiving a patient response that the set of actions causes one or more undesirable sensations during the set of actions, the processing circuit is configured to: Output a second set of requests from the set of requests for display on the user interface, wherein the second set of requests includes prompts that enable the user to identify the unpleasant feeling from a menu that may contain an unpleasant feeling; Receive a second set of responses from the set of responses received from the user interface, wherein the set of second responses includes the user's identification of the undesirable sensation described in the menu of the undesirable sensation; and Based on the second response of this group, one or more adjustments to the control strategy are determined.

8. The system of claim 6, wherein, In response to receiving a patient response that the set of actions did not cause an undesirable sensation during the set of actions, the processing circuit is configured to: Output the second request in the group of requests for display on the user interface, wherein the second request includes a prompt for the user to indicate whether the group of actions caused an unpleasant sensation after the group of actions; and Receive a second response from the group of responses from the user interface, wherein the second response includes a patient response in which the group of actions causes an undesirable sensation after the group of actions or a patient response in which the group of actions does not cause an undesirable sensation after the group of actions.

9. The system of claim 8, wherein, In response to a patient response that the set of actions causes an undesirable sensation after the set of actions, the processing circuit is configured to: Output a third set of requests from the set of requests for display on the user interface, wherein the set of third requests includes prompts that enable the user to identify the undesirable sensation from a menu that may contain such sensations; Receive a third set of responses from the set of responses received from the user interface, wherein the set of third responses includes the user's identification of the undesirable sensation described in the menu of the undesirable sensation; and Based on the third response of this group, one or more adjustments to the control strategy are determined.

10. The system of claim 9, wherein, This set of actions is the first set of actions, wherein the message is the first message, and wherein, in response to receiving a patient response that the first set of actions does not cause an undesirable sensation after the first set of actions, the processing circuit is configured to: Determine whether to prompt the patient to perform the second set of actions; and In response to determining that the patient is prompted to perform a second set of actions, a second message is output to be displayed by the user interface, the second message requesting the patient to perform the second set of actions.

11. The system of claim 1, wherein, The processing circuit is further configured to: Before outputting a message requesting the patient to perform the set of actions, an instruction is output to cause the medical device to measure one or more parameters; and The medical device receives data indicating one or more measurement parameters, wherein the data corresponds to a time period during which the patient performs the set of actions.

12. The system of claim 11, wherein, The one or more parameters include any one or a combination of the following: the amplitude of one or more stimulation pulses of the electrical stimulation therapy, the characteristics of the evoked compound action potential (ECAP) in response to the one or more stimulation pulses, the patient's electrocardiogram (EGM), the patient's exercise level, or any combination thereof.

13. The system of claim 1, wherein, The medical devices include implantable medical devices (IMDs).

14. The system of claim 1, wherein, The external device includes the user interface.

15. A system for controlling electrical stimulation therapy, the system comprising: Processing circuitry; A storage device storing instructions, which, when executed by the processing circuit, cause the processing circuit to perform a method comprising: Output a message requesting the patient to perform a set of actions for display on the user interface; Receive user input from the user interface, the user input indicating a patient response associated with the set of actions; and Based on the user input, one or more adjustments to a control strategy are determined, the control strategy controlling electrical stimulation delivered by the medical device based on at least one evoked compound action potential (ECAP) sensed by the medical device.

16. The system of claim 15, the method further comprising outputting instructions via a communication circuit to the medical device for configuring the one or more adjustments to the control strategy.

17. The system of claim 15, wherein, The control strategy controls one or more parameters of the electrical stimulation therapy delivered by the medical device, wherein the electrical stimulation therapy comprises a plurality of stimulation pulses, and wherein determining the one or more adjustments to the control strategy includes: The one or more adjustments are determined to cause the control strategy to perform any one or a combination of the following: decreasing the decrement step size or decrement step rate of the plurality of stimulation pulses in response to one or more events associated with the patient response; increasing the decrement step size or decrement step rate of the plurality of stimulation pulses in response to the one or more events associated with the patient response; decreasing the increment step size or increment step rate of the plurality of stimulation pulses in response to the one or more events associated with the patient response; and increasing the increment step size or increment step rate of the plurality of stimulation pulses in response to one or more transient events associated with the patient response.

18. The system of claim 15, wherein, The method further includes: A set of requests is output for display on the user interface, wherein each request in the set includes a prompt for obtaining information relating to one or more patient sensations corresponding to the action, and wherein receiving the user input instructing the patient to respond includes: A set of responses is received from the user interface, wherein each response in the set represents a patient's response to a corresponding request in the set of requests.

19. The system of claim 18, wherein, The method further includes: Output the first request in the group of requests for display on the user interface, wherein the first request includes a prompt for the user to indicate whether the group of actions caused an unpleasant sensation during the group of actions; and Receive a first response from the group of responses from the user interface, wherein the first response includes a patient response in which the group of actions causes an undesirable sensation during the group of actions or a patient response in which the group of actions does not cause an undesirable sensation during the group of actions.

20. The system of claim 19, wherein, In response to receiving a patient response that the set of actions causes one or more undesirable sensations during the set of actions, the method further includes: Output a second set of requests from the set of requests for display on the user interface, wherein the second set of requests includes prompts that enable the user to identify the unpleasant feeling from a menu that may contain an unpleasant feeling; Receive a second set of responses from the set of responses received from the user interface, wherein the set of second responses includes the user's identification of the undesirable sensation described in the menu of the undesirable sensation; and Based on the second response of this group, one or more adjustments to the control strategy are determined.

21. The system of claim 19, wherein, In response to receiving a patient response that the set of actions did not cause an undesirable sensation during the set of actions, the method further includes: Output the second request in the group of requests for display on the user interface, wherein the second request includes a prompt for the user to indicate whether the group of actions caused an unpleasant sensation after the group of actions; and Receive a second response from the group of responses from the user interface, wherein the second response includes a patient response in which the group of actions causes an undesirable sensation after the group of actions or a patient response in which the group of actions does not cause an undesirable sensation after the group of actions.

22. The system of claim 21, wherein, In response to a patient response to receiving a set of actions that elicits an undesirable sensation following the set of actions, the method further includes: Output a third set of requests from the set of requests for display on the user interface, wherein the set of third requests includes prompts that enable the user to identify the undesirable sensation from a menu that may contain such sensations; Receive a third set of responses from the set of responses received from the user interface, wherein the set of third responses includes the user's identification of the undesirable sensation described in the menu of the undesirable sensation; and Based on the third response of this group, one or more adjustments to the control strategy are determined.

23. The system of claim 22, wherein, The set of actions is the first set of actions, wherein the message is the first message, and wherein, in response to receiving a patient response that the first set of actions does not cause an undesirable sensation after the first set of actions, the method further includes: Determine whether to prompt the patient to perform the second set of actions; and In response to determining that the patient is prompted to perform a second set of actions, a second message is output to be displayed by the user interface, the second message requesting the patient to perform the second set of actions.

24. The system of claim 15, wherein the method further comprises: Before outputting a message requesting the patient to perform the set of actions, output an instruction for the medical device to measure one or more parameters; as well as The medical device receives data indicating one or more measurement parameters, wherein the data corresponds to a time period during which the patient performs the set of actions.

25. A computer-readable medium comprising instructions that, when executed by a processor, cause the processor to: Output a message requesting the patient to perform a set of actions for display on the user interface; Receive user input from the user interface, the user input indicating a patient response associated with the set of actions; and Based on the user input, one or more adjustments to a control strategy are determined, the control strategy controlling electrical stimulation delivered by the medical device based on at least one evoked compound action potential (ECAP) sensed by the medical device.

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