Feedback parameters for closed-loop neuromodulation systems

Abstract

A system may include a memory configured to store at least one feedback parameter that at least partially defines closed-loop control of one or more stimulation parameters that define electrical stimulation therapy. The system may further include processing circuity configured to receive a first signal indicative of a patient condition of a patient; determine, based on the first signal, an adjusted value of the at least one feedback parameter; receive sensed information representative of a second signal sensed from the patient; compare the sensed information to the adjusted value of the at least one feedback parameter; and control, based on the comparison of the sensed information to the adjusted value, stimulation circuitry to deliver the electrical stimulation therapy.

Description

Docket No.: A0012338W001FEEDBACK PARAMETERS FOR CLOSED-LOOP NEUROMODULATION SYSTEMSCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority to U.S. Provisional Application No. 63 / 726,105 filed November 27, 2024, which is incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The present disclosure generally relates to medical devices and, more particularly, electrical stimulation therapyBACKGROUND

[0003] Medical devices may be external or implanted and may be used to deliver electrical stimulation therapy to various tissue sites of a patient to treat a variety of symptoms or conditions such as chronic pain, tremor, Parkinson’s disease, other movement disorders, epilepsy, urinary or fecal incontinence, sexual dysfunction, obesity, or gastroparesis. A medical device may deliver electrical stimulation therapy via one or more leads that include electrodes located proximate to target locations associated with the brain, the spinal cord, pelvic nerves, peripheral nerves, or the gastrointestinal tract of a patient. Hence, electrical stimulation may be used in different therapeutic applications, such as deep brain stimulation (DBS), spinal cord stimulation (SCS), pelvic stimulation, gastric stimulation, or peripheral nerve field stimulation (PNFS).SUMMARY

[0004] In general, the present disclosure describes devices, systems, and techniques for determining a value of at least one parameter involved in closed-loop control of electrical stimulation therapy. The parameter may be a feedback parameter (e.g., sensed electrical signal) with a value that is tracked to identify when the system need to adjust a stimulation parameter defining the electrical stimulation therapy. In some examples, the determined parameter may even be one or more stimulation parameters that define the electrical stimulation therapy according to closed-loop control.

[0005] In some examples, the at least one feedback parameter may include a threshold value, and electrical stimulation therapy may be controlled based on a comparison of one or more features of a signal sensed from a patient with the at least one feedback parameter. For example, the at least one feedback parameter may include a local field potential (LFP) activity (e.g., spectral power of the LFP signal), an evoked resonant neural activity, or an evoked potential neural activity. An initial value for the threshold value of the at least one feedback parameterDocket No.: A0012338W001 may initially be set based on patient assessment made in a clinical setting. However, the effectiveness of the threshold value can be influenced by factors of daily life outside the clinic setting, such as medication (e.g., wash in / out, changes, or dosing times), exercise, and disease progression. Thus, the threshold value may be adjusted, partially or fully automatically, based on a patient condition. The patient condition may be based on a signal indicative of a change of a state of the patient. For example, the signal may indicate that the patient is engaged in exercise or some strenuous activity, or that the patient is relatively sedentary, and the system may automatically adjust the threshold accordingly. The patient may provide an input to generate the signal indicative of the change of the state of the patient (e.g., tap a screen or press a button). In some examples, the signal is received from a sensor, for example, an accelerometer, electrical sensing circuitry, etc.

[0006] In examples, an example system includes a memory configured to store at least one feedback parameter that at least partially defines closed-loop control of one or more stimulation parameters that define electrical stimulation therapy. The example system further includes processing circuity configured to receive a first signal indicative of a patient condition of a patient. The processing circuitry may be further configured to determine, based on the first signal, an adjusted value of the at least one feedback parameter. The processing circuitry may be further configured to receive sensed information representative of a second signal sensed from the patient. The processing circuitry may be further configured to compare the sensed information to the adjusted value of the at least one feedback parameter. The processing circuitry may be further configured to control, based on the comparison of the sensed information to the adjusted value, stimulation circuitry to deliver the electrical stimulation therapy.

[0007] In examples, an example method includes receiving, by processing circuitry, a first signal indicative of a patient condition of a patient. The method may further include determining, by the processing circuitry, based on the first signal, an adjusted value of at least one feedback parameter that at least partially defines closed-loop control of one or more stimulation parameters that define electrical stimulation therapy. The method may further include receiving, by the processing circuitry, sensed information representative of a second signal sensed from the patient. The method may further include comparing, by the processing circuitry, the sensed information to the adjusted value of the at least one feedback parameter. The method may further include controlling, by the processing circuitry, based on the comparison of the sensed information to the adjusted value, stimulation circuitry to deliver the electrical stimulation therapy.

[0008] In examples, an example system includes a memory configured to store at least one feedback parameter that at least partially defines closed-loop control of one or more stimulationDocket No.: A0012338W001 parameters that define electrical stimulation therapy. The system further includes processing circuitry configured to receive a first signal indicative of a patient condition of a patient. The processing circuitry may be further configured to receive sensed information representative of a second signal sensed from the patient. The processing circuitry may be further configured to receive a third signal indicative of a time period. The processing circuitry may be further configured to determine, based on the first signal and the third signal, an adjusted value of the at least one feedback parameter. The processing circuitry may be further configured to compare the sensed information to the adjusted value of the at least one feedback parameter. The processing circuitry may be further configured to control, based on the comparison of the sensed information to the adjusted value, stimulation circuitry to deliver the electrical stimulation therapy.

[0009] In examples, an example method includes receiving, by processing circuitry, a first signal indicative of a patient condition of a patient. The method may further include receiving, by the processing circuitry, sensed information representative of a second signal sensed from the patient. The method may further include receiving, by the processing circuitry, a third signal indicative of a time period. The method may further include determining, by the processing circuitry, based on the first signal and the third signal, an adjusted value of at least one feedback parameter that at least partially defines closed-loop control of one or more stimulation parameters that define electrical stimulation therapy. The method may further include comparing, by the processing circuitry, the sensed information to the adjusted value of the at least one feedback parameter. The method may further include controlling, by the processing circuitry, based on the comparison of the sensed information to the adjusted value, stimulation circuitry to deliver the electrical stimulation therapy.

[0010] The details of one or more examples of the techniques of this disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the techniques will be apparent from the description and drawings, and from the claims.BRIEF DESCRIPTION OF DRAWINGS

[0011] FIG. l is a conceptual diagram illustrating an example system that includes an implantable medical device (IMD) configured to deliver DBS to a patient according to an example of the techniques of the disclosure.

[0012] FIG. 2 is a block diagram of the example IMD of FIG. 1 for delivering DBS therapy according to an example of the techniques of the disclosure.

[0013] FIG. 3 is a block diagram of the external programmer of FIG. 1 for controlling delivery of DBS therapy according to an example of the techniques of the disclosure.Docket No.: A0012338W001

[0014] FIG. 4 is a conceptual diagram illustrating an example home screen for navigating within a user interface according to an example of the techniques of the disclosure.

[0015] FIG. 5 is a conceptual diagram illustrating an example screen for displaying a selected sensing electrode combination and signal of interest for a lead according to an example of the techniques of the disclosure.

[0016] FIG. 6 is a conceptual diagram illustrating an example screen for selecting an adaptive therapy mode according to an example of the techniques of the disclosure.

[0017] FIG. 7 is a conceptual diagram illustrating an example screen for determining one or more thresholds according to an example of the techniques of the disclosure.

[0018] FIG. 8 is a conceptual diagram illustrating a scheme for determining a threshold based on a sensed value of a feedback parameter according to an example of the techniques of the disclosure.

[0019] FIG. 9 is a conceptual diagram illustrating scheme for determining a threshold based on sensed values of a feedback parameter over a time period before, during, or after a patient condition according to an example of the techniques of the disclosure.

[0020] FIG. 10 is a conceptual diagram illustrating scheme for determining a threshold based on sensed values of a feedback parameter associated with occurrences of a patient condition at different time periods according to an example of the techniques of the disclosure.

[0021] FIG. 11 is a flowchart illustrating an example operation for adjusting one or more thresholds and controlling adjustment of electrical stimulation based on the one or more thresholds according to an example of the techniques of the disclosure.DETAILED DESCRIPTION

[0022] The present disclosure describes example devices, systems, and techniques for adjusting at least one parameter (e.g., a feedback parameter that may include a threshold value or a stimulation parameter) at least partially defining electrical stimulation therapy. The electrical stimulation therapy may be adaptive electrical stimulation therapy in which a system can adjust one or more parameters of stimulation therapy, based on chronic, averaged, and, optionally, filtered data. The data may include characteristic values, e.g., amplitude values, of a bioelectric signal, such as a local field potential (LFP) signal, or an evoked resonant neural activity (ERNA) signal, of a patient. A patient may suffer from one or more symptoms treatable by electrical stimulation therapy. For example, a patient may suffer from brain disorder such as Parkinson’s disease, Alzheimer’s disease, or another type of movement disorder. Deep brain stimulation (DBS) may be an effective treatment to reduce the symptoms associated with such disorders.Docket No.: A0012338W001

[0023] At least one feedback parameter may be used for closed-loop control of electrical stimulation therapy. For example, the at least one feedback parameter may include an LFP signal. In an example monitoring scheme based on a single-threshold, electrical stimulation is delivered if the LFP signal exceeds a threshold, and electrical stimulation is terminated when the LFP signal is reduced below the threshold. This threshold may be an instantaneous amplitude of a characteristic of the LFP signal, such as the amplitude of spectral power of a predetermined frequency band, but the threshold may be other features or characteristics of the LFP signal such as overall LFP power, strongest LFP frequency band, LFP voltage (e.g., sensed voltage in the time domain), etc. Certain techniques of configuring DBS therapy, e.g., automated DBS (aDBS) therapy, for a patient may include setting the threshold value of at least one feedback parameter that at least partially defines closed-loop control of one or more stimulation parameters that define electrical stimulation therapy. The threshold value may be initially set based on an acute bioelectric signal sensed in a clinic, such as during system calibration. In some examples, the acute bioelectric signal sensed in the clinic may not be representative of typical system performance. For example, the in-clinic time may be for a very short time (e.g., less than 30 minutes) and the patient may not conduct normal activities or experience normal medication changes that would occur during a typical day. Thus, the threshold that is initially set may not account for deviations caused by conditions that a patient may face outside a clinical setting. Based on the initially set threshold, the patient may not receive adequate stimulation, or may receive overstimulation, outside the clinical setting.

[0024] As described herein, various devices, systems, and techniques enable determination of an adjusted value of the at least one feedback parameter. For example, a patient may generate an input marking an event, for example a perception of overstimulation. The adjusted value may be determined based on the patient input. Thus, the initially set threshold may be adjusted to a new threshold value accounting for a patient input, or a signal indicative of a patient state.

[0025] In some examples, an example system includes a memory configured to store at least one feedback parameter that at least partially defines closed-loop control of one or more stimulation parameters that define electrical stimulation therapy. The system may further include processing circuity configured to receive a first signal indicative of a patient condition of a patient. The processing circuitry may be further configured to determine, based on the first signal, an adjusted value of the at least one feedback parameter. The processing circuitry may be further configured to receive sensed information representative of a second signal sensed from the patient. The processing circuitry may be further configured to compare the sensed information to the adjusted value of the at least one feedback parameter. The processing circuitry may be further configured to control, based on the comparison of the sensed information to theDocket No.: A0012338W001 adjusted value, stimulation circuitry to deliver the electrical stimulation therapy. By determining the adjusted value of the at least one feedback parameter based on the first signal indicative of the patient condition, the stimulation circuitry may be controlled to deliver electrical stimulation while resisting or preventing under-stimulation, over-stimulation, or inducing an onset of side effects.

[0026] These various features of the systems and techniques described herein may provide advantages over other systems and improve system functionality and patient outcomes. For example, by controlling stimulation therapy according to the adjusted threshold value, the techniques of this disclosure may result in the threshold value being more representative of typical system operation and typical patient activity and condition. By selecting more representative thresholds, the techniques of this disclosure may improve an accuracy of patient therapy, which may help to reduce or prevent patient side effects and symptoms. In some examples, an initial value for the threshold may also be determined based on a patient condition, for example, in a non-clinical setting, or without requiring a clinician’s intervention. Thus, a need for clinical intervention may be reduced for setting or adjusting threshold values used for controlling electrical stimulation therapy.

[0027] In some examples, more than one threshold value may be used to control electrical stimulation therapy. For example, an upper threshold value may be associated with a symptom of a disease, and a lower threshold maybe associated with an onset of at least one side effect. In such examples, a reduction in a sensed value below the upper threshold value is indicative of a reduction in at least one symptom of a disease, and a reduction in the sensed value of the activity parameter below the lower threshold value is indicative of an onset of at least one side effect associated with the deep brain stimulation. Because electrical stimulation is not changed until the LFP passes the thresholds, patients may experience either symptoms, or side effects, if the thresholds are not properly set, or if the thresholds do not account for present patient conditions.

[0028] Systems and techniques according to the present disclosure may be used to set initial values or determine adjusted values for the upper threshold and / or the lower threshold, while accounting for a patient condition. Thus, the electrical stimulation therapy may be controlled to maintain the sensed value (e.g., associated with an LFP signal) between the two thresholds.

[0029] FIG. 1 is a conceptual diagram illustrating an example system 100 that includes an implantable medical device (IMD) 106 configured to deliver electrical stimulation therapy to a patient 112 according to an example of the techniques of the disclosure, in accordance with one or more techniques of this disclosure. In some examples, the electrical stimulation therapy includes deep brain stimulation (DBS). In some examples, DBS may be adaptive (aDBS) in the sense that IMD 106 may adjust, increase, or decrease the value of one or more stimulationDocket No.: A0012338W001 parameters that define the DBS in response to changes in patient activity or movement, a severity of one or more symptoms of a disease of the patient, a presence of one or more side effects due to the DBS, or one or more sensed signals of the patient, etc. For example, system 100 may use a bioelectric signal, e.g., an LFP signal, of patient 112 as a control signal such that the IMD 106 adjusts the magnitude of the one or more parameters of the electrical stimulation in response to the magnitude or change in magnitude of characteristic values of the sensed signal, e.g., an amplitude, of the bioelectric signal. This process enables system 100 to automatically adjust stimulation therapy in response to changes to the patient condition, such as changes to brain activity indicative of a level of therapy efficacy.

[0030] Example therapy system 100 includes medical device programmer 104, IMD 106, lead extension 110, and leads 114A and 114B with respective sets of electrodes 116, 118. In the example shown in FIG. 1, electrodes 116, 118 of leads 114 A, 114B are positioned to deliver electrical stimulation to a tissue site within brain 120, such as a deep brain site under the dura mater of brain 120 of patient 112. In some examples, delivery of stimulation to one or more regions of brain 120, such as the subthalamic nucleus, globus pallidus or thalamus, may be an effective treatment to manage movement disorders, such as Parkinson’s disease. Some or all of electrodes 116, 118 also may be positioned to sense the bioelectric signal within brain 120 of patient 112. In some examples, some of electrodes 116, 118 may be configured to sense the bioelectric signal and others of electrodes 116, 118 may be configured to deliver adaptive electrical stimulation to brain 120. In other examples, all of electrodes 116, 118 are configured to both sense the bioelectric signal and deliver adaptive electrical stimulation to brain 120.

[0031] IMD 106 includes a therapy module (e.g., which may include processing circuitry, signal generation circuitry or other electrical circuitry configured to perform the functions attributed to IMD 106) that includes a stimulation generator configured to generate and deliver electrical stimulation therapy to patient 112 via a subset of electrodes 116, 118 of leads 114A and 114B, respectively. The subset of electrodes 116, 118 that are used to deliver electrical stimulation to patient 112, and, in some cases, the polarity of the subset of electrodes 116, 118, may be referred to as a stimulation electrode combination. As described in further detail below, the stimulation electrode combination can be selected for a particular patient 112 and target tissue site (e.g., selected based on bioelectric signal information and the patient condition). The group of electrodes 116, 118 includes at least one electrode and can include a plurality of electrodes. In some examples, the plurality of electrodes 116 and / or 118 may have a complex electrode geometry such that two or more electrodes are located at different positions around the perimeter of the respective lead.Docket No.: A0012338W001

[0032] According to some techniques of the disclosure, system 100, via IMD 106, delivers electrical stimulation therapy defined by one or more parameters, such as voltage or current amplitude within a therapeutic window (e.g., a window defined by one or more limits for the voltage or current amplitude), adjusted based on the characteristic the bioelectric signal feature and the one or more threshold values. System 100 may continuously monitor the bioelectric signal feature.

[0033] In some examples, system 100 is configured to adjust at least one parameter of the electrical stimulation therapy in response to the bioelectric signal crossing the one or more threshold values. In some examples, the one or more threshold values include one or both of an upper threshold value or a lower threshold value that forms a homeostatic window. The homeostatic window may be used as part of an adaptive mode for adjusting stimulation therapy over time. In some examples, system 100 may change other parameters in response to sensed signals such as stimulation pulse frequency, pulse burst duration, pulse burst frequency, duty cycle, or electrode combination. Throughout this disclosure, the terms “limit,” “threshold,” and “bound” can refer to similar concepts, e.g., each defines a window or range of acceptable values associated with adaptive therapy. Although the homeostatic window may be described as including an upper and lower threshold value, only a single threshold value (e.g., upper threshold or lower threshold) may be used in other examples.

[0034] In some examples, system 100 is configured to receive a first signal indicative of a patient condition of a patient. System 100 may be further configured to determine, based on the first signal, an adjusted value of the at least one feedback parameter. System 100 may be further configured to receive sensed information representative of a second signal sensed from the patient. System 100 may be further configured to compare the sensed information to the adjusted value of the at least one feedback parameter. System 100 may be further configured to control, based on the comparison of the sensed information to the adjusted value, stimulation circuitry (e.g., of IMD 106) to deliver the electrical stimulation therapy (e.g., via electrodes 116 and 118).

[0035] As described herein, system 100 can monitor one or more signals of patient 112 for selecting one or more parameters defining stimulation and / or adjusting stimulation in a closed- loop manner. In one example, the signal is a bioelectric signal of patient 112, such as an LFP signal with a frequency within a Beta frequency band and / or a Gamma frequency band of the brain of patient 112. For example, the monitored signal may be a power of the respective Beta frequency band and / or Gamma frequency band. In yet a further example, the signal can be a signal indicative of a bioelectric parameter of the patient, such as a severity of a symptom of the patient, a movement of the patient, a posture of the patient, a respiratory function of the patient, a heart rate, or an activity level of the patient. System 100 may use a single signal or combinationDocket No.: A0012338W001 of different signals for initially selecting and / or adjusting one or more parameters that define subsequent electrical stimulation therapy. System 100, via IMD 106, can be configured to deliver electrical stimulation to patient 112, wherein one or more parameters defining the electrical stimulation are related by a transfer function (which may or may not be proportional to the magnitude of the monitored signal or adjusted in response to a magnitude of the monitored signal exceeding one or more thresholds).

[0036] System 100 may be configured to treat one or more patient conditions, such as a movement disorder, neurodegenerative impairment, a mood disorder, or a seizure disorder of patient 112. Patient 112 ordinarily is a human patient. In some cases, however, therapy system 100 may be applied to other mammalian or non-mammalian, non-human patients. While movement disorders and neurodegenerative impairment are primarily referred to herein, in other examples, therapy system 100 may provide therapy to manage symptoms of other patient conditions, such as, but not limited to, seizure disorders (e.g., epilepsy) or mood (or psychological) disorders (e.g., major depressive disorder (MDD), bipolar disorder, anxiety disorders, post-traumatic stress disorder, dysthymic disorder, and obsessive-compulsive disorder (OCD)). At least some of these disorders may be manifested in one or more patient movement behaviors. As described herein, a movement disorder or other neurodegenerative impairment may include symptoms such as, for example, muscle control impairment, motion impairment or other movement problems, such as rigidity, spasticity, bradykinesia, rhythmic hyperkinesia, nonrhythmic hyperkinesia, and akinesia. In some cases, the movement disorder may be a symptom of Parkinson’s disease. However, the movement disorder may be attributable to other patient conditions.

[0037] In some examples, the bioelectric signals sensed within brain 120 may reflect changes in electrical current produced by the sum of electrical potential differences across brain tissue, or any voltage potentials between electrodes. In some examples, the bioelectric signal that is used to select a stimulation electrode combination may be sensed within the same region of brain 120 as the target tissue site for the electrical stimulation. As previously indicated, these tissue sites may include tissue sites within anatomical structures such as the thalamus, subthalamic nucleus or globus pallidus of brain 120, as well as other target tissue sites. The specific target tissue sites and / or regions within brain 120 may be selected based on the patient condition. Thus, in some examples, the electrodes used for delivering electrical stimulation may be different than the electrodes used for sensing the bioelectric signal. In other examples, the same electrodes may be used to deliver electrical stimulation and sense brain signals. However, this configuration may require system 100 to switch between stimulation generation and sensing circuitry and may reduce the time system 100 can sense brain signals.Docket No.: A0012338W001

[0038] Electrical stimulation generated by IMD 106 may be configured to manage a variety of disorders and conditions. In some examples, the stimulation generator of IMD 106 is configured to generate and deliver electrical stimulation pulses to patient 112 via electrodes of a selected stimulation electrode combination. However, in other examples, the stimulation generator of IMD 106 may be configured to generate and deliver a continuous wave signal, e.g., a sine wave or triangle wave. In either case, a stimulation generator within IMD 106 may generate the electrical stimulation therapy for DBS according to a therapy program that is selected at that given time in therapy. In examples in which IMD 106 delivers electrical stimulation in the form of stimulation pulses, a therapy program may include a set of therapy parameter values (e.g., stimulation parameters), such as a stimulation electrode combination for delivering stimulation to patient 112, pulse frequency, pulse width, stimulation cycling, and a current or voltage amplitude of the pulses. As previously indicated, the electrode combination may indicate the specific electrodes 116, 118 that are selected to deliver stimulation signals to tissue of patient 112 and the respective polarities of the selected electrodes. In some examples, a clinician may set up a plurality of therapy programs that patient 112 can manually switch between and / or that IMD 106 can cycle through. Based on patient feedback and / or sensed signals, the clinician, the patient, and / or IMD 106 may select a therapy program for subsequent use.

[0039] IMD 106 may be implanted within a subcutaneous pocket above the clavicle, or, alternatively, on or within cranium 122 or at any other suitable site within patient 112. Generally, IMD 106 is constructed of a biocompatible material that resists corrosion and degradation from bodily fluids. IMD 106 may comprise a hermetic housing to substantially enclose components, such as a processor, therapy module, and memory.

[0040] As shown in FIG. 1, implanted lead extension 110 is coupled to IMD 106 via connector 108 (also referred to as a connector block or a header of IMD 106). In the example of FIG. 1, lead extension 110 traverses from the implant site of IMD 106 and along the neck of patient 112 to cranium 122 of patient 112 to access brain 120. In the example shown in FIG. 1, leads 114A and 114B (collectively “leads 114”) are implanted within the right and left hemispheres, respectively, of patient 112 in order deliver electrical stimulation to one or more regions of brain 120, which may be selected based on the patient condition or disorder controlled by therapy system 100. 1 n some examples, more than two leads may be used in total or in each hemisphere, e.g., two leads per hemisphere (4 leads total), or an uneven number of leads between the hemispheres. The specific target tissue site and the stimulation electrodes used to deliver stimulation to the target tissue site, however, may be selected, e.g., according to the identified patient behaviors and / or other sensed patient parameters. Other lead 114 and IMD 106 implantDocket No.: A0012338W001 sites are contemplated. For example, IMD 106 may be implanted on or within cranium 122, in some examples. Or leads 114 may be implanted within the same hemisphere or IMD 106 may be coupled to a single lead implanted in a single hemisphere.

[0041] Existing lead sets include axial leads carrying ring electrodes disposed at different axial positions and so-called “paddle” leads carrying planar arrays of electrodes. Selection of electrode combinations within an axial lead, a paddle lead, or among two or more different leads presents a challenge to the clinician. In some examples, more complex lead array geometries may be used.

[0042] Although leads 114 are shown in FIG. 1 as being coupled to a common lead extension 110, in other examples, leads 114 may be coupled to IMD 106 via separate lead extensions or directly to connector 108. Leads 114 may be positioned to deliver electrical stimulation to one or more target tissue sites within brain 120 to manage patient symptoms associated with a movement disorder of patient 112. Leads 114 may be implanted to position electrodes 116, 118 at desired locations of brain 120 through respective holes in cranium 122. Leads 114 may be placed at any location within brain 120 such that electrodes 116, 118 are capable of providing electrical stimulation to target tissue sites within brain 120 during treatment. For example, electrodes 116, 118 may be surgically implanted under the dura mater of brain 120 or within the cerebral cortex of brain 120 via a burr hole in cranium 122 of patient 112, and electrically coupled to IMD 106 via one or more leads 114.

[0043] In the example shown in FIG. 1, electrodes 116, 118 of leads 114 are shown as ring electrodes. Ring electrodes may be used in aDBS applications because they are relatively simple to program and are capable of delivering an electrical field to any tissue adjacent to electrodes 116, 118. In other examples, electrodes 116, 118 may have different configurations. For example, in some examples, at least some of the electrodes 116, 118 of leads 114 may have a complex electrode array geometry that is capable of producing shaped electrical fields. The complex electrode array geometry may include multiple electrodes (e.g., partial ring or segmented electrodes) around the outer perimeter of each lead 114, rather than one ring electrode. In this manner, electrical stimulation may be directed in a specific direction from leads 114 to enhance therapy efficacy and reduce possible adverse side effects from stimulating a large volume of tissue. In some examples, a housing of IMD 106 includes one or more stimulation and / or sensing electrodes. In alternative examples, leads 114 may have shapes other than elongated cylinders as shown in FIG. 1. For example, leads 114 may be paddle leads, spherical leads, bendable leads, or any other type of shape effective in treating patient 112 and / or minimizing invasiveness of leads 114.Docket No.: A0012338W001

[0044] In the example shown in FIG. 1, IMD 106 includes a memory to store a plurality of therapy programs that each define a set of therapy parameter values. In some examples, IMD 106 may select a therapy program from the memory based on various parameters, such as sensed patient parameters and the identified patient behaviors. IMD 106 may generate electrical stimulation based on the selected therapy program to manage the patient symptoms associated with a movement disorder.

[0045] External programmer 104 is configured to wirelessly communicate with IMD 106 as needed to provide or retrieve therapy information. Programmer 104 is an external computing device that a user, e.g., a clinician and / or patient 112, may use to communicate with IMD 106. For example, programmer 104 may be a clinician programmer that the clinician uses to communicate with IMD 106 and program one or more therapy programs for IMD 106. Alternatively, programmer 104 may be a patient programmer that allows patient 112 to select programs and / or view and modify therapy parameters. The clinician programmer may include more programming features than the patient programmer. In other words, more complex or sensitive tasks may only be allowed by the clinician programmer to prevent an untrained patient from making undesirable changes to IMD 106.

[0046] When programmer 104 is configured for use by the clinician, programmer 104 may be used to transmit initial programming information to IMD 106. This initial information may include hardware information, such as the type of leads 114 and the electrode arrangement, the position of leads 114 within brain 120, the configuration of electrode array 116, 118, initial programs defining therapy parameter values, and any other information the clinician desires to program into IMD 106. Programmer 104 may also be capable of completing functional tests (e.g., measuring the impedance of electrodes 116, 118 of leads 114). In addition, or as an alternative, to programmer 104, a different external computing device may perform any of the functionality of programmer 104. The external computing device may be a networked device and in communication with IMD 106 directly or via programmer 104.

[0047] The clinician may also store therapy programs within IMD 106 with the aid of programmer 104. During a programming session, system 100 may determine one or more therapy programs that may provide efficacious therapy to patient 112 to address symptoms associated with the patient condition, and, in some cases, specific to one or more different patient states, such as a sleep state, movement state or rest state. For example, system 100 may select one or more stimulation electrode combinations with which stimulation is delivered to brain 120. During the programming session, system 100 may evaluate the efficacy of the specific program being evaluated based on feedback provided by the clinician or patient 112 or based on one or more physiological parameters of patient 112 (e.g., muscle activity, muscle tone, rigidity, tremor,Docket No.: A0012338W001 etc.). Alternatively, identified patient behavior from video information may be used as feedback during the initial and subsequent programming sessions.

[0048] Programmer 104 may also be configured for use by patient 112. When configured as a patient programmer, programmer 104 may have limited functionality (compared to a clinician programmer) in order to prevent patient 112 from altering critical functions of IMD 106 or applications that may be detrimental to patient 112. In this manner, programmer 104 may only allow patient 112 to mark events and to adjust values for certain therapy parameters or set an available range of values for a particular therapy parameter. When programmer 104 is configured for use by patient 112 (e.g., a patient programmer), programmer 104 may have a limited set of adjustments and / or data available to the user compared with a clinician programmer. In this manner, the patient programmer version may prevent the patient from causing detrimental changes to therapy but allow the patient to make some adjustments to therapy as desired.

[0049] Therapy system 100 may be implemented to provide chronic stimulation therapy to patient 112 over the course of several months or years. However, system 100 may also be employed on a trial basis to evaluate therapy before committing to full implantation. If implemented temporarily, some components of system 100 may not be implanted within patient 112. For example, patient 112 may be fitted with an external medical device, such as a trial stimulator, rather than IMD 106. The external medical device may be coupled to percutaneous leads or to implanted leads via a percutaneous extension. If the trial stimulator indicates DBS system 100 provides effective treatment to patient 112, the clinician may implant a chronic stimulator within patient 112 for relatively long-term treatment.

[0050] Although IMD 104 is described as delivering electrical stimulation therapy to brain 120, IMD 106 may be configured to direct electrical stimulation to other anatomical regions of patient 112 in other examples. As examples, IMD 106 may be configured to sacral neuromodulation therapy or tibial neuromodulation therapy. In some examples, system 100 may include an implantable drug pump in addition to, or in place of, IMD 106. Further, an IMD may provide other electrical stimulation such as spinal cord stimulation to treat a movement disorder.

[0051] According to the techniques of the disclosure, system 100 can define a homeostatic window and / or a therapeutic window for delivering aDBS to patient 112. System 100 may adaptively deliver electrical stimulation and adjust one or more parameters defining the electrical stimulation within a parameter range defined by upper and lower limits of the therapeutic window based on the activity of the bioelectric signal, e.g., LFP signal, within the homeostatic window. For example, system 100 may adjust the one or more parameters defining the electrical stimulation in response to the sensed bioelectric signal falling below the lower threshold value orDocket No.: A0012338W001 exceeding the upper threshold value of the homeostatic window but may not adjust the one or more parameters defining the electrical stimulation such that they fall below the lower limit or exceed the upper limit of the therapeutic window.

[0052] In one example, external programmer 104 is configured to issue commands to IMD 106, via instructions transmitted from external programmer 104 to IMD 106, causing IMD 106 to deliver electrical stimulation therapy via electrodes 116, 118 via leads 114. As described above, in one example, the therapeutic window can define an upper bound and / or a lower bound for one or more parameters defining the delivery of electrical stimulation therapy to patient 112. In other words, the one or more bounds for the therapeutic window may refer to the limits of values that the parameter defining stimulation can be adjusted. For example, the one or more parameters include a current amplitude (for a current-controlled system) or a voltage amplitude (for a voltage-controlled system), a pulse rate or frequency, and a pulse width. In examples where the electrical stimulation is delivered according to a “burst” of pulses, or a series of electrical pulses defined by an “on-time” and an “off-time,” the one or more parameters may further define one or more of a number of pulses per burst, an on-time, and an off-time. In one example, the therapeutic window defines an upper bound and a lower bound for one or more parameters, such as upper and lower threshold for a current amplitude of the electrical stimulation therapy (in current-controlled systems) or upper and lower threshold of a voltage amplitude of the electrical stimulation therapy (in voltage-controlled systems). While the examples herein are typically given with respect to adjusting a voltage amplitude or a current amplitude, the techniques herein may equally be applied to a homeostatic window and a therapeutic window using other parameters, such as, e.g., pulse rate or pulse width.

[0053] In some examples, a patient may provide feedback, e.g., via programmer 104, to adjust a threshold. The threshold may include one or both thresholds of the homeostatic window, or a threshold associated with any suitable control scheme. For example, programmer 104 may provide an input mechanism for the patient to provide an input indicating when therapy is no longer effective or a side effect is felt by patient 112. Programmer 104 may then adjust a threshold of the homeostatic window and / or a bound of the therapeutic window to reduce the issue associated with the patient feedback.

[0054] For example, system 100 may be configured to receive, via programmer 104 or IMD 106, a first signal indicative of a patient condition of the patient. System 100 may be further configured to determine, based on the first signal, an adjusted value of the at least one feedback parameter. For example, the adjusted value may be adjusted from an initial value, or may be used to set the initial value. The adjusted value is compared with a physiological signal or a bioelectric signal. For example, system 100 may be further configured to receive, viaDocket No.: A0012338W001 programmer 104 or IMD 106, sensed information representative of a second signal sensed from the patient. The second signal may be the bioelectric signal. System 100 may be further configured to compare the sensed information to the adjusted value of the at least one feedback parameter, and control stimulation circuitry based on the comparison.

[0055] For example, system 100, via programmer 104 or IMD 106, may adjust one or more parameters of the electrical stimulation, such as voltage or current amplitude, within the therapeutic window based on patient input that adjusts the homeostatic window, or based on the bioelectric signal. In particular, system 100 may adjust a parameter of the electrical stimulation, automatically in response to the sensed signal satisfying the one or more thresholds of the homeostatic window and / or in response to patient input that adjusts the homeostatic window, provided the value of the electrical stimulation parameter is constrained to remain within a range specified by the upper and lower bound of the therapeutic window. This range may be considered to include the upper and lower bound themselves.

[0056] In some examples where system 100 adjusts multiple parameters of the electrical stimulation, system 100 may adjust at least one of a voltage amplitude or current amplitude, a stimulation frequency, a sensing frequency of interest, a pulse width, a stimulation cycling setting, a selection of electrodes, and the like. In such an example, system 100 may set an order or sequence for adjustment of the parameters (e.g., adjust voltage amplitude or current amplitude, then adjust stimulation frequency, and then adjust the selection of electrodes). In other examples, system 100 may randomly select a sequence of adjustments to the multiple parameters. In either example, system 100 may adjust a value of a first parameter of the parameters of the electrical stimulation. If the signal does not exhibit a response to the adjustment of the first parameter, system 100 may adjust a value of a second parameter of the parameters of the electrical stimulation, and so on until the signal returns to within the homeostatic window.

[0057] To adaptively adjust a parameter that defines DBS based on the bioelectric signal, for example, two or more electrodes 116, 118 of IMD 106 may be configured to monitor the bioelectric signal of patient 112. In some examples, at least one of electrodes 116, 118 may be provided on a housing of IMD 106, providing a unipolar stimulation and / or sensing configuration. In one example, the bioelectric signal may be selected to be a signal within a Beta frequency band of brain 120 of patient 112. For example, bioelectric signals within the Beta frequency band of patient 112 may correlate to one or more symptoms of Parkinson’s disease in patient 112. Generally, bioelectric signals within the Beta frequency of patient 112 may be approximately proportional to the severity of the symptoms of patient 112. For example, as tremor induced by Parkinson’s disease increases, bioelectric signals within the Beta frequency of patient 112 increase (e.g., magnitude of the signal and / or spectral power). Moreover, bioelectricDocket No.: A0012338W001 signals within the Beta frequency are considered proportional because system 100 may be configured such that an increase in signal magnitude may trigger system 100 to increase delivered stimulation therapy magnitude according to disclosed techniques. Similarly, as tremor induced by Parkinson’s disease decreases, bioelectric signals within the Beta frequency of patient 112 decrease (e.g., magnitude of the signal and / or spectral power), and the decrease may trigger system 100 to decrease the magnitude of delivered stimulation. However, in some examples, these relationships between signal changes and symptom changes may be inversed for some patients which require the system to react in an inverse manner.

[0058] In some examples, IMD 106 may include a sensor, for example, one or more of an accelerometer, a bonded piezoelectric crystal, a mercury switch, or a gyro. In some examples, these sensors may provide a signal that indicates a bioelectric parameter of the patient, which in turn varies as a function of patient activity or patient state. For example, the device may monitor a signal that indicates the heart rate, electrocardiogram (ECG) morphology, electroencephalogram (EEG) morphology, respiration rate, respiratory volume, core temperature, subcutaneous temperature, or muscular activity of the patient.

[0059] The architecture of system 100 illustrated in FIG. 1 is shown as an example. The techniques as set forth in this disclosure may be implemented in the example system 100 of FIG. 1, as well as other types of systems not described specifically herein. Nothing in this disclosure should be construed so as to limit the techniques of this disclosure to the example architecture illustrated by FIG. 1.

[0060] FIG. 2 is a block diagram of the example IMD 106 of FIG. 1 for delivering DBS therapy according to an example of the techniques of the disclosure, in accordance with one or more techniques of this disclosure. In the example shown in FIG. 2, IMD 106 includes processing circuitry 210, memory 211, stimulation generator 202, sensing circuitry 204, switch module 206, telemetry module 208, sensor 212, and power source 220. Each of these modules may be or may include electrical circuitry configured to perform the functions attributed to each respective module. For example, processing circuitry 210 may include one or more processors as part of the processing circuitry, switch module 206 may include switch circuitry, sensing circuitry 204 may include sensing circuitry, stimulation generator 202 may include stimulation generation circuitry, and telemetry module 208 may include telemetry circuitry. Switch module 206 may not be necessary for multiple current source and sink configurations in which each current source and sink are directly connected to each electrode but may be connected or disconnected via a respective switch. Memory 211 may include any volatile or non-volatile media, such as a random-access memory (RAM), read only memory (ROM), non-volatile RAM (NVRAM), electrically erasable programmable ROM (EEPROM), flash memory, and the like.Docket No.: A0012338W001Memory 211 may store computer-readable instructions that, when executed by processing circuitry 210, cause IMD 106 to perform various functions. Memory 211 may be a storage device or other non-transitory medium.

[0061] In the example shown in FIG. 2, memory 211 stores therapy programs 214 and sense electrode combinations and medication information 218 in separate memories within memory 211 or separate areas within memory 211. Sense and stimulation electrode combinations 218 stores sense electrode combinations and associated stimulation electrode combinations. As described above, in some examples, the sense and stimulation electrode combinations may include the same subset of electrodes 116, 118, a housing of IMD 106 functioning as an electrode, or may include different subsets or combinations of such electrodes. Thus, memory 211 can store a plurality of sense electrode combinations and, for each sense electrode combination, store information identifying the stimulation electrode combination that is associated with the respective sense electrode combination. The associations between sense and stimulation electrode combinations can be determined, e.g., automatically by processing circuitry 210. In some examples, corresponding sense and stimulation electrode combinations may comprise some or all of the same electrodes. In other examples, however, some or all of the electrodes in corresponding sense and stimulation electrode combinations may be different. For example, a stimulation electrode combination may include more electrodes than the corresponding sense electrode combination in order to increase the efficacy of the stimulation therapy. In some examples, as discussed above, stimulation is delivered via a stimulation electrode combination to a tissue site that is different than the tissue site closest to the corresponding sense electrode combination but is within the same region, e.g., the thalamus, of brain 120 in order to mitigate any irregular oscillations or other irregular brain activity within the tissue site associated with the sense electrode combination. Alternatively, stimulation may be delivered via one of leads 114, and sensing may be performed via the other lead of leads 114.

[0062] Stimulation generator 202, under the control of processing circuitry 210, generates stimulation signals for delivery to patient 112 via selected combinations of electrodes 116, 118. An example range of electrical stimulation parameters believed to be effective in DBS to manage a movement disorder of patient include:

[0063] 1. Pulse Rate, i.e., Frequency: between approximately 40 Hertz and approximately500 Hertz, such as between approximately 1 to 185 Hertz or such as approximately 140 Hertz.

[0064] 2 In the case of a voltage controlled system, Voltage Amplitude: between approximately 0.1 volts and approximately 50 volts, such as between approximately 2 volts and approximately 3 volts.Docket No.: A0012338W001

[0065] 3. In the alternative case of a current controlled system, Current Amplitude: between approximately 0.2 milliamps to approximately 100 milliamps, such as between approximately 1.3 milliamps and approximately 2.0 milliamps.

[0066] 4. Pulse Width: between approximately 10 microseconds and approximately 5000 microseconds, such as between approximately 100 microseconds and approximately 1000 microseconds, or between approximately 180 microseconds and approximately 450 microseconds.

[0067] Accordingly, in some examples, stimulation generator 202 generates electrical stimulation signals in accordance with the electrical stimulation parameters noted above, subject to application of the upper and lower limit of a therapeutic window to one or more of the parameters, such that an applicable parameter resides within the range prescribed by the window. Other ranges of therapy parameter values may also be useful and may depend on the target stimulation site within patient 112. While stimulation pulses are described, stimulation signals may be of any form, such as continuous-time signals (e.g., sine waves) or the like.

[0068] Processing circuitry 210 may include fixed function processing circuitry and / or programmable processing circuitry, and may comprise, for example, any one or more of 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 the functions attributed to processing circuitry 210 herein may be embodied as firmware, hardware, software or any combination thereof. Processing circuitry 210 may control stimulation generator 202 according to therapy programs 214 stored in memory 211 to apply particular stimulation parameter values specified by one or more of programs, such as voltage amplitude or current amplitude, pulse width, or pulse rate.

[0069] In the example shown in FIG. 2, the set of electrodes 116 includes electrodes 116A, 116B, 116C, and 116D, and the set of electrodes 118 includes electrodes 118A, 118B, 118C, and 118D. Processing circuitry 210 also controls switch module 206 to apply the stimulation signals generated by stimulation generator 202 to selected combinations of electrodes 116, 118. In particular, switch module 206 may couple stimulation signals to selected conductors within leads 114, which, in turn, deliver the stimulation signals across selected electrodes 116, 118. Switch module 206 may be a switch array, switch matrix, multiplexer, or any other type of switching module configured to selectively couple stimulation energy to selected electrodes 116, 118 and to selectively sense the bioelectric signal with selected electrodes 116, 118. Hence, stimulation generator 202 is coupled to electrodes 116, 118 via switch module 206 and conductors within leads 114. In some examples, however, IMD 106 does not include switch module 206.Docket No.: A0012338W001

[0070] Stimulation generator 202 may be a single channel or multi-channel stimulation generator. In particular, stimulation generator 202 may be capable of delivering a single stimulation pulse, multiple stimulation pulses, or a continuous signal at a given time via a single electrode combination or multiple stimulation pulses at a given time via multiple electrode combinations. In some examples, however, stimulation generator 202 and switch module 206 may be configured to deliver multiple channels on a time-interleaved basis (e.g., pulses from one channel are at least partially alternating with at least some pulses from another channel). For example, switch module 206 may serve to time divide the output of stimulation generator 202 across different electrode combinations at different times to deliver multiple programs or channels of stimulation energy to patient 112. Alternatively, stimulation generator 202 may comprise multiple voltage or current sources and sinks that are coupled to respective electrodes to drive the electrodes as cathodes or anodes. In this example, IMD 106 may not require the functionality of switch module 206 for time-interleaved multiplexing of stimulation via different electrodes.

[0071] Electrodes 116, 118 on respective leads 114 may be constructed of a variety of different designs. For example, one or both of leads 114 may include two or more electrodes at each longitudinal location along the length of the lead, such as multiple electrodes at different perimeter locations around the perimeter of the lead at each of the locations A, B, C, and D. In one example, the electrodes may be electrically coupled to switch module 206 via respective wires that are straight or coiled within the housing the lead and run to a connector at the proximal end of the lead. In another example, each of the electrodes of the lead may be electrodes deposited on a thin film. The thin film may include an electrically conductive trace for each electrode that runs the length of the thin film to a proximal end connector. The thin film may then be wrapped (e.g., a helical wrap) around an internal member to form the lead 114. These and other constructions may be used to create a lead with a complex electrode geometry.

[0072] Although sensing circuitry 204 is incorporated into a common housing with stimulation generator 202 and processing circuitry 210 in FIG. 2, in other examples, sensing circuitry 204 may be in a separate housing from IMD 106 and may communicate with processing circuitry 210 via wired or wireless communication techniques.

[0073] Sensor 212 may include one or more sensing elements that sense values of a respective patient parameter. For example, sensor 212 may include one or more accelerometers, optical sensors, chemical sensors, temperature sensors, pressure sensors, or any other types of sensors. Sensor 212 may output patient parameter values that may be used as feedback to control delivery of therapy. IMD 106 may include additional sensors within the housing of IMD 106 and / or coupled via one of leads 114 or other leads. In some examples, IMD 106 receives sensorDocket No.: A0012338W001 signals wirelessly from remote sensors via telemetry module 208. In some examples, one or more of these remote sensors is external to patient (e.g., carried on the external surface of the skin, attached to clothing, or otherwise positioned external to the patient).

[0074] Telemetry module 208 is configured to support wireless communication between IMD 106 and an external programmer 104 or another computing device under the control of processing circuitry 210. Processing circuitry 210 of IMD 106 may receive, as updates to programs, values for various stimulation parameters such as magnitude and electrode combination, from programmer 104 via telemetry module 208. The updates to the therapy programs may be stored within therapy programs 214 portion of memory 211. Telemetry module 208 in IMD 106, as well as telemetry modules in other devices and systems described herein, such as programmer 104, may accomplish communication by radiofrequency (RF) communication techniques. In addition, telemetry module 208 may communicate with external medical device programmer 104 via proximal inductive interaction of IMD 106 with programmer 104. Accordingly, telemetry module 208 may send information to external programmer 104 on a continuous basis, at periodic intervals, or upon request from IMD 106 or programmer 104.

[0075] Power source 220 delivers operating power to various components of IMD 106. Power source 220 may include a rechargeable or non-rechargeable battery and a power generation circuit to produce the operating power. Recharging may be accomplished through proximal inductive interaction between an external charger and an inductive charging coil within IMD 220. In some examples, power requirements may be small enough to allow IMD 220 to utilize patient motion and implement a kinetic energy-scavenging device to trickle charge a rechargeable battery. In other examples, traditional batteries may be used for a limited period of time.

[0076] According to the techniques of the disclosure, processing circuitry 210 of IMD 106 controls stimulation generator 202 to deliver of electrical stimulation therapy to patient 112 via electrodes 116, 118 interposed along leads 114 (and optionally switch module 206). One or more parameters of the electrical stimulation therapy may include a current amplitude (for a current- controlled system) or a voltage amplitude (for a voltage-controlled system), a pulse rate or frequency, and a pulse width, or quantity of pulses per cycle. The collection of one or more of these parameter values may define a parameter set that defines a therapy program. In examples where the electrical stimulation is delivered according to a “burst” of pulses, or a series of electrical pulses defined by an “on-time” and an “off-time,” the one or more parameters may further define one or more of a number of pulses per burst, an on-time, and an off-time. In one example, the therapeutic window defines an upper limit and / or a lower limit for a voltage amplitude of the electrical stimulation therapy. In another example, the therapeutic windowDocket No.: A0012338W001 defines an upper limit and / or a lower limit for a current amplitude of the electrical stimulation therapy. In particular, a parameter of the electrical stimulation therapy, such as voltage or current amplitude, is constrained to a therapeutic window having an upper limit and a lower limit, such that the voltage or current amplitude may be adjusted provided the amplitude remains greater than or equal to the lower limit and less than or equal to the upper limit. It is noted that a single limit may be used in some examples.

[0077] In one example, processing circuitry 210, via electrodes 116, 118 of IMD 106, is configured to monitor the behavior of a signal of patient 112 that correlates to one or more symptoms of a disease of patient 112 within a homeostatic window. Processing circuitry determines one or more threshold values associated with the homeostatic window based on a chronically sensed bioelectric signal, e.g., LFP signal. Processing circuitry 210, via electrodes 116, 118, delivers aDBS to patient 112 and may adjust one or more parameters defining the electrical stimulation within a parameter range defined by lower and upper limits of a therapeutic window based on the activity of the sensed signal within the homeostatic window.

[0078] In some examples, processing circuitry 210 continuously measures the signal in real time or near-real time. In other examples, processing circuitry 210 periodically samples the signal according to a predetermined frequency or after a predetermined amount of time. In some examples, processing circuitry 210 periodically samples the signal at a frequency selected from a range of appropriate frequencies, such as a frequency of approximately 150 Hertz.

[0079] Furthermore, processing circuitry 210 delivers electrical stimulation therapy that is constrained by an upper limit and a lower limit of a therapeutic window. In some examples, values defining the therapeutic window are stored within memory 211 of IMD 106. For example, in response to detecting that characteristic values, e.g., amplitude values, of the bioelectric signal have deviated from the homeostatic window, processing circuitry 210 of IMD 106 may adjust one or more parameters of the electrical stimulation therapy to provide responsive treatment to patient 112.

[0080] In response to detecting that the signal has exceeded an upper threshold of the homeostatic window and prior to delivering the electrical stimulation therapy, processing circuitry 210 increases an amplitude of stimulation (e.g., but not above the upper limit) in order to bring the signal back down below the upper threshold value. For example, in a voltage- controlled system wherein the clinician has set the upper limit of the therapeutic window to be 3 Volts, processing circuitry 210 can increase the voltage amplitude to values no greater than 3 Volts in an attempt to decrease the brain signal below the upper threshold value.

[0081] In another example, in response to detecting that the signal has fallen below a lower threshold value of the homeostatic window and prior to delivering the electrical stimulationDocket No.: A0012338W001 therapy, processing circuitry 210 decreases the voltage amplitude, for example, but not lower than the magnitude of the lower limit. For example, in the above voltage-controlled system wherein the clinician has set the lower bound of the therapeutic window to be 1.2 Volts, processing circuitry 210 can decrease the voltage amplitude down to no lower than 1.2 Volts in an attempt to raise the brain signal back above the lower threshold value and into the homeostatic window. Thus, processing circuitry 210 of IMD 106 may deliver aDBS to patient 112 wherein the one or more parameters defining the aDBS is within the therapeutic window defined by a lower and upper limit for the parameter.

[0082] In the foregoing example, the limit of the therapeutic window is inclusive (i.e., the upper and lower limit are valid values for the one or more parameters). However, in other examples, the limit of the therapeutic window is exclusive (i.e., the upper and lower limits are not valid values for the one or more parameters). In such an example of an exclusive therapeutic window, processing circuitry 210 instead sets the adjustment to the one or more parameters to be the next highest valid value (in the case of an adjustment potentially exceeding the upper limit) or the next lowest valid value (in the case of an adjustment potentially exceeding the lower limit).

[0083] FIG. 3 is a block diagram of the external programmer of FIG. 1 for controlling delivery of DBS therapy according to an example of the techniques of the disclosure, in accordance with one or more techniques of this disclosure. FIG. 3 is a block diagram of the external programmer 104 of FIG. 1. Although programmer 104 may generally be described as a hand-held device, programmer 104 may be a larger portable device or a more stationary device. In some examples, programmer 104 may be referred to as a tablet computing device. In addition, in other examples, programmer 104 may be included as part of an external charging device or include the functionality of an external charging device.

[0084] As illustrated in FIG. 3, programmer 104 may include a processing circuitry 310, memory 311, user interface 302, telemetry module 308, and power source 320. Memory 311 may store instructions that, when executed by processing circuitry 310, cause processing circuitry 310 and external programmer 104 to provide the functionality ascribed to external programmer 104 throughout this disclosure. Each of these components, or modules, may include electrical circuitry that is configured to perform some or all of the functionality described herein. For example, processing circuitry 310 may include processing circuitry configured to perform the processes discussed with respect to processing circuitry 310.

[0085] In general, programmer 104 comprises any suitable arrangement of hardware, alone or in combination with software and / or firmware, to perform the techniques attributed to programmer 104, and processing circuitry 310, user interface 302, and telemetry module 308 of programmer 104. In various examples, programmer 104 may include one or more processors,Docket No.: A0012338W001 which may include fixed function processing circuitry and / or programmable processing circuitry, as formed by, for example, one or more microprocessors, DSPs, ASICs, FPGAs, or any other equivalent integrated or discrete logic circuitry, as well as any combinations of such components. Programmer 104 also, in various examples, may include a memory 311, such as RAM, ROM, PROM, EPROM, EEPROM, flash memory, a hard disk, or an optical media (e.g., DVD or CD- ROM), comprising executable instructions for causing the one or more processors to perform the actions attributed to them. Moreover, although processing circuitry 310 and telemetry module 308 are described as separate modules, in some examples, processing circuitry 310 and telemetry module 308 may be functionally integrated with one another. In some examples, processing circuitry 310 and telemetry module 308 correspond to individual hardware units, such as ASICs, DSPs, FPGAs, or other hardware units.

[0086] Memory 311 (e.g., a storage device) may store instructions that, when executed by processing circuitry 310, cause processing circuitry 310 and programmer 104 to provide the functionality ascribed to programmer 104 throughout this disclosure. For example, memory 311 may include instructions that cause processing circuitry 310 to select one or more parameters for electrical stimulation or adaptive stimulation according to sensed signals or receive user input and send a corresponding command to IMD 104, or instructions for any other functionality. In addition, memory 311 may include a plurality of programs, where each program includes a parameter set that defines stimulation therapy.

[0087] User interface 302 may include a button or keypad, lights, a speaker for voice commands, a display, such as a liquid crystal (LCD), light-emitting diode (LED), or organic light-emitting diode (OLED). In some examples the display may be a touch screen. User interface 302 may be configured to display any information related to the delivery of stimulation therapy, identified patient behaviors, sensed patient parameter values, automatically selected parameters, prompts for user input regarding stimulation parameters or adaptive stimulation parameters, patient behavior criteria, or any other such information. User interface 302 may also receive user input via user interface 302. The input may be, for example, in the form of pressing a button on a keypad or selecting an icon from a touch screen. User interface 302 may refer to hardware configured to present information to the user and / or receive input from the user. In some examples, processing circuitry 310 directly controls this hardware. In other examples, processing circuitry 310 may communicate with drive hardware that controls hardware of user interface 302. In some examples, user interface 302 may include display and / or interactive display configurations as described herein.

[0088] Telemetry module 308 may support wireless communication between IMD 106 and programmer 104 under the control of processing circuitry 310. Telemetry module 308 may alsoDocket No.: A0012338W001 be configured to communicate with another computing device via wireless communication techniques, or direct communication through a wired connection. In some examples, telemetry module 308 provides wireless communication via an RF or proximal inductive medium. In some examples, telemetry module 308 includes an antenna, which may take on a variety of forms, such as an internal or external antenna. In some examples, telemetry modules 308 may support communications with intermediate devices between programmer 104 and IMD 106 or other external devices.

[0089] Examples of local wireless communication techniques that may be employed to facilitate communication between programmer 104 and IMD 106 include RF communication according to the 802.11 or Bluetooth specification sets or other standard, inductive telemetry, or any proprietary telemetry protocols. In this manner, other external devices may be capable of communicating with programmer 104 without needing to establish a secure wireless connection. As described herein, telemetry module 308 may be configured to transmit a spatial electrode movement pattern or other stimulation parameter values to IMD 106 for delivery of stimulation therapy.

[0090] According to the techniques of the disclosure, in some examples, processing circuitry 310 of external programmer 104 defines the parameters of a therapeutic window, stored in memory 311, for delivering DBS to patient 112. In one example, processor 311 of external programmer 104, via telemetry module 308, issues commands to IMD 106 causing IMD 106 to deliver electrical stimulation therapy via electrodes 116, 118.

[0091] In another example, values defining the therapeutic window are stored within a memory 311 (FIG. 3) of external programmer 104. In this example, in response to detecting that the signal has deviated from the homeostatic window, processing circuitry 210 of IMD 106 transmits, via telemetry module 208, data representing the measurement of the signal to external programmer 104.

[0092] In some examples, in response to detecting that the signal has exceeded an upper threshold of the homeostatic window, processing circuitry 210 of IMD 106 transmits, via telemetry module 208, data representing the measurement of the signal to external programmer 104. External programmer 104 may determine to adjust a parameter value to reduce the signal below the upper threshold as long as the parameter value remains within the one or more limits to the parameter.

[0093] The following examples illustrate various user interfaces and techniques for managing the sensing of bioelectric signals, programming adaptive stimulation therapy, and managing electrical stimulation as described herein. Programmer 104, or another external computing device, may output the user interfaces and screens described herein. The example user interfaceDocket No.: A0012338W001 screens may be separately presented or selectable in any order, or programmer 106 (for example) may present each screen in order as part of a guided programming process to assist the user through the programming process and during follow-up visits. During programming, user input may be prompted at various times, either to select parameter values or to confirm automatically selected parameter values. In some examples, programmer 106 may perform each step automatically and present the user with fully automated and selected parameters at the end of the process. The user may confirm the parameter values or review one or more of the parameter values using each respective screen of the user interface as needed to customize the stimulation therapy, which may include adaptive stimulation therapy such as aDBS. During follow-up visits or at other times after programming, the user interface screens may present alerts and other information to the clinician.

[0094] FIG. 4 is a conceptual diagram illustrating an example home screen for navigating within a user interface according to an example of the techniques of the disclosure. User interface 400 may include several different screens as the user can navigate to different functions to view sensed information, view stored data, or adjust various stimulation parameter values. As shown in the example of FIG. 4, home screen 402 includes information associated with patient 112, such as patient specific information 406 such as name, patient ID, date of birth, and patient diagnosis. Other information may include device specific information such as model number, implant date, battery level, and estimated batter life remaining. Information such as impedance status for the system and event summary may also be provided in the home screen 402. Screen 402 may also include stimulation toggle switch 404 that, when selected, toggles between turning stimulation on or turning stimulation off. Stimulation toggle switch 404 may be provided in some, most, or all of the different screens within user interface 400 to enable the user to turn stimulation on or off at any time. Alert button 410 shows “no alerts” because there are no alerts to be shown. However, if there are alerts for the user, alert button 410 may indicate that there are alerts, or the number of alerts, and alert button 410 may be selectable to cause user interface 400 to show a list of the alerts for the user.

[0095] The home screen 402 in FIG. 4 may also include a menu 408 that includes several selectable buttons that enable the user to navigate to other screen and functionality supported by user interface 400. These selectable buttons include “setup,” “stimulation,” “impedance,” “MRI eligibility,” “replacement,” “events,” and “end session.” Programmer 104 may switch to the appropriate screen in response to user selection of the respective selectable button.

[0096] As shown in the example of FIG. 4, in response to user selection, the setup button takes the user to screens associated with selecting electrode combinations for sensing and / or stimulation and / or frequency for sensing. In response to user selection, the stimulation buttonDocket No.: A0012338W001 takes the user to screens associated with managing electrical stimulation therapy for the patient, such as selecting an adaptive stimulation mode, selecting thresholds for the adaptive mode, selecting parameters that define stimulation, bounds for stimulation parameters, or any other parameters related to stimulation therapy. In response to user selection, the impedance button takes the user to screens associated with viewing impedances of one or more electrode combinations and / or leads and running impedance testing for any electrical pathways.

[0097] The MRI eligibility button takes the user to screens associated with checking MRI eligibility of any implanted device (e.g., IMD 106) and / or placing the implanted device into an MRI eligible mode. The replacement button causes user interface 400 to displace screens related to when the IMD 106 should be replaced (e.g., remaining operational life for a primary cell non- rechargeable power supply). The events button enables the user to navigate to various screens that display events and data associated with sensing and delivering electrical stimulation. The end session button enables the user to terminate the management session via user interface 400. In addition to the menu, user interface 400 may include a stimulation toggle switch that enables the user to request turning stimulation on or off. These different navigation categories in menu 408 are merely examples, and the functionality within each category may be separated into additional categories or combined into fewer categories in other examples.

[0098] User interface 400 may be configured for a clinician programmer that enables the clinician to oversee all aspects of stimulation therapy and / or sensing, both manual and / or automated. In some examples, user interface 400 may enable the language of the clinician programmer to be different from a patient programmer configured to enable the patient to control a subset of features related to IMD 106. For example, user interface 400 may enable the clinician to set up the patient programmer language in the setup button, where the patient programmer language is different from the language of user interface 400 presented by the clinician programmer. For example, user interface 400 may enable the clinician to set up therapy group names, device names, and patient events to appear in a patient’s local language irrespective of the primary or supported clinician language of user interface 400. In this manner, user interface 400 may enable the clinician (or a translator assisting the clinician) to program group names and patient events in the desired language for the patient even if it is not the primary language of the clinician.

[0099] FIG. 5 is a conceptual diagram illustrating an example screen 500 of user interface 400 for displaying a selected sensing electrode combination and signal of interest for a lead according to an example of the techniques of the disclosure. In some examples, electrode combinations 502 may be referred to as sense channels. In some examples, system 100 may automatically select an electrode combination based on a weighted summation of multipleDocket No.: A0012338W001 sensing metrics (or other criteria). In some examples, the sensing metric information is collected when system 100 controls sensing circuitry to sense respective bioelectric signals from each of the plurality of electrode combinations 502. System 100 may perform this collection of the bioelectric signals upon navigation to screen 500 or prior to this step of the process. System 100 may in any example analyze the sensed signals and generate one or more recommended electrode combinations for sensing and / or a frequency for sensing signals during therapy, such as during adaptive stimulation (e.g., aDBS). In some examples, sensing metrics include bioelectric signal information, e.g., LFP signal information, whether the electrode combination supports already configured therapy electrodes, and the quantity of artifacts associated with each electrode combination.

[0100] Screen 500 may include information summarizing the metrics of selected electrode combination 504. Lead 516 shows the electrodes of the lead used for the selected electrode combination 504. Screen 500 may include a LFP power (e.g., the magnitude of the spectral power) vs. frequency graph 512. In other words, graph 512 shows data in the frequency domain. Data line 510 corresponds to the powers for the combination “0 to 2” that is selected and shows the highest magnitude of power at the frequency of 22.48 Hz. This frequency may also be recommended for this reason. Processing circuitry, e.g., processing circuitry 210 and / or 310, may control sensing circuitry 204 to sense and record the LFP signal within a 5 Hz band including the 22.48 Hz frequency. In some examples, the LFP signal within the 5 Hz band and / or the LFP signal at the 22.48 Hz frequency may be referred to as the signal of interest. Generally, the recommended electrode combinations are those with peaks present at a certain frequency as shown in the LFP power vs. frequency graph. Additionally, electrode combinations with relatively low artifact levels and already supported therapy electrodes are the best electrode combinations. In some examples, the weighting of each metric may be patient-dependent. In other examples, the metric weights are based on aggregate patient data.

[0101] If desired, the user may choose different electrode combinations and frequencies. For example, screen 500 may receive user selection of a different electrode combination of electrode combinations 504, which may cause screen 500 to update the corresponding selected data line in graph 512 and, if necessary, the frequency. The user may select a different frequency using slider 506 on graph 512 or another numerical input field in other examples. Selection of the close button 518 will accept the selected or recommended parameters shown in screen 500 for subsequent sensing, close screen 500, and may prompt system 100 to continue automated programming. In some examples, a different “save” or “confirm” button may be presented for the user to select when satisfied with the identified parameters in screen 500. The techniquesDocket No.: A0012338W001 described herein are not limited to LFP signals. Other bioelectric signals may be used in other examples (e.g., ERNA signals). LFP signals serve merely as a non-limiting example.

[0102] In some examples, screen 500 includes auto selection button 508. The user may select auto selection button 508, and processing circuitry 310 may select an electrode combination and a signal of interest. Screen 500 may include a pop-up window (not depicted), confirming the selections. The user may either confirm the selections or adjust the selections.

[0103] During the automated selection process discussed herein, programmer 104 may initiate an automatic scan of brain signals from all or most electrode combinations available to enable programmer 104 or the user to identify where signals might be located (which hemisphere, which region of a lead, which specific combinations of contacts) for the purpose of identifying such signals, the integrity or quality of the recording system, and then guiding sensing configuration and / or stimulation parameters values

[0104] In this manner, user interface 400 can provide a view of all signals in a hemisphere simultaneously and enable selection of one signal to be compared to the others. Programmer 104 may measure aspects of the signal (e.g., difference between maximum and / or minimum at a specific frequency of interest). Programmer 104 may enable IMD 106 to continuously record a subset of signals. In some examples, programmer 104 performs statistical comparisons (e.g., an energy in a region of frequencies compared to the energy at a specific peak, the relative amplitude above 1 / frequency of the curve, the width of the peak, or simultaneous comparison or measurement of two or more peaks. In some examples, user interface 400 may provide additional views for leads having electrodes at different locations around a perimeter of a lead (e.g., segmented electrodes of directional leads). User interface 400 may also provide visualization of anatomic structures or other reference in combination with a signal location (e.g., whether or not a signal is in or out of target, or if a signal is medial or lateral from an anatomical structure).

[0105] FIG. 6 is a conceptual diagram illustrating an example screen 600 of user interface 400 for selecting an adaptive therapy mode, e.g., an aDBS mode, from two or more different adaptive modes. As shown in the example of FIG. 6, user interface 400 may include screen 600 that indicates the automated system selection of dual threshold mode 604, single threshold mode 606, or single threshold inverse mode 608. Dual threshold mode 604 is shown as selected. Dual threshold mode 604 enables the system to adjust stimulation amplitude based on upper and lower thresholds of the LFP signals. Single threshold mode 606 enables the system to increase stimulation when LFP signals are above the threshold, and single threshold inverse mode 608 enables the system to decrease stimulation when LFP signals are above the threshold.Docket No.: A0012338W001

[0106] This feature of user interface 400 for programming aDBS is intended to enable IMD 106 to automatically adjust, within system-defined limits and / or clinician-defined limits, one or more stimulation parameters based on changes in brain state. A patient’s brain state will be measured using a brain signal, such as LFPs, recorded concurrently from the implanted electrodes during therapy. The goal of the automatic adjustment of therapy may be to maintain the brain state (as defined by these signals) within a specified range (e.g., the range between an upper and lower threshold in the dual threshold mode example), understanding that clinical symptoms and side effects may be well correlated with these detected brain states. In this manner of managing brain states, the user may be able to manage clinical symptoms and side effects. This feature is referred to as closed loop DBS or aDBS.

[0107] In this manner, user interface 400 enables the user to monitor automated adaptive therapy configuration by confirming or modifying algorithm, thresholds, and / or stimulation settings for adaptive stimulation modes. Menu 602 allows the user to monitor the automated programming process and to switch between setup stages. Adaptive mode is the current setup stage in this example. The user may select previous button 610 to go back to a previous setup stage, e.g., BrainSense setup, or may select next button 612 to move on to a next setup stage, e.g., thresholds. In some examples, processing circuitry 310 (or processing circuitry 210) controls stimulation generator 202 to generate electrical stimulation at a plurality of values of a stimulation parameter, e.g., current amplitude, that at least partially defines the electrical stimulation during a period of time. In some examples, user interface 400 presents screen 600 to the user after selecting an adaptive mode based on information representative of bioelectric signals sensed by sensing circuitry 204.

[0108] In some examples, in addition to the information representative of the bioelectric signals, processing circuitry 310 determines which adaptive mode of the plurality of adaptive modes to select based on user input. For example, user input may comprise information regarding a condition of a patient, e.g., patient 112, which may be used to determine which aDBS mode to use for patient 112. Example conditions may include different symptoms or diseases, patient specific reactions to stimulation (e.g., dyskinesia at higher stimulation amplitudes), or unstable reactions to medication also consumed by the patient. For example, single threshold inverse mode may be selected for patients that have dyskinesia at higher stimulation amplitudes or if the patient responds in the Gamma band. In some examples, the system selects the single or dual threshold for Beta band sensing when the patient needs help controlling swings in symptoms from taking medication. Additionally, or alternatively, user interface 400 may enable the user to select a different aDBS mode, i.e., override the aDBS selection made by processing circuitry 310, by selecting a different adaptive mode in screen 600.Docket No.: A0012338W001

[0109] While the techniques are described using processing circuitry 310, other processing circuitry, such as processing circuitry 210 or a combination of processing circuitry 310 and processing circuitry 210, may also be used. Selection of next button 612 may save the selected adaptive mode and move to the next screen of user interface 400.

[0110] FIG. 7 is a conceptual diagram illustrating an example screen 700 of user interface 400 for determining one or more thresholds (e.g., example feedback parameters) according to an example of the techniques of the disclosure. Example screen 700 may include a graph 702 of a bioelectric sign (e.g., an LFP signal) vs. time. Default, placeholder, or historical values for threshold values, e.g., for an upper threshold value 704 and a lower threshold value 706, may be represented by respective threshold lines superimposed over graph 702. A period of time 708 may be marked on graph 702.[oni] In some examples, screen 700 includes an initial selection button 714, and an auto adjustment button 716. When the user (e.g., a clinician) selects initial selection button 714, the user is able to set or change at least one threshold value (e.g., one or both of upper threshold value 704 or lower threshold value 706). For example, graph 702 may represent an LFP signal sensed during a clinical observation period of time 708. Based on graph 702, or some other criteria, the user may set initial values for one or both of upper threshold value 704 or lower threshold value 706. As an example, the user sets initial values for the thresholds, then continue observing the patient in a clinical setting, and continue adjusting the thresholds in the clinical setting. For example, the user may raise the upper threshold until the patient exhibits a sufficient reduction in symptoms. If the patient exhibits side effects, the user may raise the lower threshold value. After the patient exhibits a predetermined response (e.g., with a reduction in symptoms and in the absence of side effects) to electrical stimulation therapy delivered in accordance to the thresholds, the clinical session may be considered complete. After the initial values are set, the user may select auto adjustment button 716, to mark commencement of automatic adjustment of one or both off upper threshold value 704 and lower threshold value 706, as described with reference to FIGS. 8 to 11. For example, the automatic adjustment may cause the initially set threshold values to be adjusted (for example, increased or decreased), in response to sensed patient conditions or patient input.

[0112] FIG. 8 is a conceptual diagram illustrating a scheme for determining a threshold based on a sensed value of a feedback parameter according to an example of the techniques of the disclosure. For example, a patient condition Cl associated with a chart of a magnitude M of at least one feedback parameter over time may be indicative of a symptom. Sensed value SI of the feedback parameter may be associated with the patient condition Cl. In some examples, processing circuitry 310 may set an adjusted value (e.g., an upper threshold value) of the at leastDocket No.: A0012338W001 one feedback parameter to be equal to sensed value SI associated with the feedback parameter. Thus, in a subsequent therapy session, when a future value of the feedback parameter increases beyond the value SI, processing circuitry 310 may cause the stimulation intensity to be increased. In other examples, processing circuitry 310 may set an adjusted value (e.g., an upper threshold value) of the at least one feedback parameter to be a modified value SMI that is a predetermined percentage or predetermined number of units less than the sensed value SI associated with the feedback parameter. For example, processing circuitry 310 may set the adjusted value of the at least one feedback parameter to be 1%, 5%, 10%, or 20% lower than the sensed value of the at least one feedback parameter associated with the patient condition, or -1, - 5, -10, or -20 units relative to a unit of measurement of the sensed value of the at least one parameter (e.g., a voltage, a charge, a current, a frequency, or some dimensionless unit). Thus, in a subsequent therapy session, when a future value of the feedback parameter increases beyond the modified value SMI (but even without reaching the sensed value SI), processing circuitry 310 may cause the stimulation intensity to be increased. In such examples, the increase in stimulation intensity may preempt an occurrence of a symptom, without the patient sensing the symptom.

[0113] A patient condition C2 may be indicative of a side effect. Sensed value S2 of the feedback parameter may be associated with the patient condition C2. In some examples, processing circuitry 310 may set an adjusted value (e.g., a lower threshold value) of the at least one feedback parameter to be equal to sensed value S2 associated with the feedback parameter. Thus, in a subsequent therapy session, when a future value of the feedback parameter reduces beyond the value S2, processing circuitry 310 may cause the stimulation intensity to be reduced. In other examples, processing circuitry 310 may set an adjusted value (e.g., a lower threshold value) of the at least one feedback parameter to be a modified value SM2 that is a predetermined percentage or predetermined number of units greater than the sensed value SI associated with the feedback parameter. For example, processing circuitry 310 may set the adjusted value of the at least one feedback parameter to be 1%, 5%, 10%, or 20% higher than the sensed value of the at least one feedback parameter associated with the patient condition, or +1, +5, +10, or +20 units relative to a unit of measurement of the sensed value of the at least one parameter (e.g., a voltage, a charge, a current, a frequency, or some dimensionless unit). Thus, in a subsequent therapy session, when a future value of the feedback parameter reduces beyond the modified value SM2 (but even without reaching the sensed value S2), processing circuitry 310 may cause the stimulation intensity to be reduced. In such examples, the increase in stimulation intensity may preempt an occurrence of a side effect, without the patient sensing the side effect.Docket No.: A0012338W001

[0114] FIG. 9 is a conceptual diagram illustrating scheme for determining a threshold based on sensed values of a feedback parameter over a time period before, during, or after a patient condition according to an example of the techniques of the disclosure. For example, a patient condition Cl in a chart of a magnitude M of at least one feedback parameter over time may be indicative of a symptom. Processing circuitry 310 may determine a plurality of sensed values over a period of time Pl associated with the patient condition Cl. For example, the period of time may initiate with the patient condition Cl, terminate with the patient condition Cl, or straddle the patient condition Cl symmetrically or asymmetrically. Processing circuitry 310 may set an adjusted value (e.g., an upper threshold value) of the at least one feedback parameter based on the plurality of sensed values associated with the period of time Pl. For example, processing circuitry 310 may set the adjusted value of the at least one feedback parameter to be an average of, a mean of, or a maximum of, or some predetermined percentage or numeric offset from the average, mean, or maximum, of the plurality of sensed values. In this way, the adjusted value of the at least one feedback parameter may account for variations in the sensed values of the at least one feedback parameter before, during, or after the patient condition.

[0115] FIG. 10 is a conceptual diagram illustrating scheme for determining a threshold based on sensed values of a feedback parameter associated with occurrences of a patient condition at different time periods according to an example of the techniques of the disclosure. For example, the patient may exhibit the same patient condition Cl in different periods Pl, P2, and P3 (during a therapy session or in different therapy sessions). For example, a certain symptom may manifest at different time periods. Processing circuitry 310 may determine a plurality of adjusted values for the periods Pl, P2, and P3 (e.g., using schemes similar to those described with reference to FIGS. 8 and 9 or any other scheme), and then determine a single adjusted value based on the plurality of adjusted values. For example, processing circuitry 310 may determine a plurality of adjusted values VI, V2, and V3 for the at least one feedback parameter for the respective time periods Pl, P2, and P3. Then, processing circuitry 310 may determine the single adjusted value as a mean, an average, a maximum, or a minimum of the plurality of adjusted values. In some examples, instead of patient condition Cl in different periods for the same patient, processing circuitry may determine the adjusted value of the at least one feedback parameter based on a cohort of patient data, or based on historical data associated with the respective patient. In some examples, processing circuitry 310 may account for different patient conditions (e.g., Cl, C2, and C3) in determining the single adjusted value, such that stimulation therapy based on the single adjusted value ultimately prevents any of the patient conditions.

[0116] While processing circuitry 310 may determine an adjusted value for at least one feedback parameter based on sensed values (e.g., magnitudes) of at least one feedback parameterDocket No.: A0012338W001(e.g., as described with reference to FIGS. 8 to 10), in some examples, processing circuitry 310 may determine the adjusted value as a rate of change threshold for the at least one feedback parameter (e.g., power of a LFP signal). For example, if the rate of change of the at least one feedback parameter is greater than a predetermined threshold, the stimulation intensity may be increased, and if the rate of change of the at least one feedback parameter is less than a predetermined threshold, the stimulation intensity may be decreased. Thus, processing circuitry 310 may determine different rates of changes of the at least one feedback parameter associated with a patient condition, and set the adjusted value as a rate of change selected from the sensed rate of changes. For example, if a first (e.g., lower) rate of change does not affect a patient condition (e.g., a symptom), but a second (e.g., higher) rate of change affects the patient condition (e.g., reduces the severity of the symptom), processing circuitry 310 may set the second rate of change as the adjusted value of the at least one feedback parameter.

[0117] In some examples, processing circuitry 310 may determine a first adjusted value based on sensed values of the at least one feedback parameter, and may determine a second adjusted value based on a rate of change of the at least one feedback parameter. For example, processing circuitry 310 may monitor the at least one feedback parameter based on the first adjusted value (e.g., a magnitude-based adjusted value). If the first adjusted value is reached, then processing circuitry 310 may monitor the at least one feedback parameter based on the second adjusted parameter (e.g., a rate-of-change based adjusted value).

[0118] In some examples, processing circuitry 310 may determine a nested set of adjusted values. For example, a first set of adjusted values (e.g., a first lower threshold value and a first upper threshold value) may be associated with a first ramp rate of stimulation (e.g., a rate of change of stimulation intensity). Processing circuitry 310 may further determine a second set of adjusted values (e.g., a second lower threshold value and a second upper threshold value) associated with a second ramp rate of stimulation. The second lower threshold value may be higher than the first lower threshold value, and the second upper threshold value may be lower than the first upper threshold value. Thus, the second ramp rate of stimulation signal may be used as long as the feedback parameter is between the second lower threshold value and the second upper threshold value, and the first ramp rate of stimulation may be used when the feedback parameter exceeds the second set of threshold values and is within the first set of threshold values.

[0119] In some examples, processing circuitry 310 may determine a predicted crossing of a threshold (e.g., an upper threshold and a lower threshold) based on a rate of change. In some such examples, processing circuitry 310 may dynamically adjusting the stimulation therapy to prevent or reduce the likelihood of crossing the threshold, without waiting for the threshold to beDocket No.: A0012338W001 reached. For example, processing circuitry may preemptively reduce stimulation intensity based on a predicted reduction of feedback parameter beyond a lower threshold value (e.g., to avoid side effects), and may preemptively increase stimulation intensity based on a predicted increase of the feedback parameter beyond an upper threshold value (e.g., to avoid a symptom).

[0120] FIG. 11 is a flowchart illustrating an example operation for selecting one or more thresholds and controlling adjustment of electrical stimulation based on the one or more thresholds according to an example of the techniques of the disclosure. The example operation of FIG. 11 will be described with respect to processing circuitry 310 of programmer 104, but any processing circuitry of system 100 may additionally or alternatively perform the example operation, such as processing circuitry 210 of IMD 106 and / or other devices or systems may be used in other examples to select the one or more thresholds for controlling adjustment of electrical stimulation. In some examples, processing circuitry of different devices may be used to collectively perform this technique in a distributed computing model.

[0121] As shown in the example of FIG. 11, the technique may include receiving, by processing circuitry 310, a first signal indicative of a patient condition of a patient (802). For example, processing circuitry 310 may receive the first signal from user interface 302. The patient condition may influence the patient’s responsivity to stimulation therapy, and thus, at least one feedback parameter may be adjusted to account for the patient condition. In some examples, the patient condition includes a patient input (for example, an input selected by the patient). For example, the patient may select an input indicative of onset of or increase in a side effect, reduction in the side effect, onset of or increase a symptom, reduction in the symptom, or an input indicating a change in patient activity (e.g., a transition between a sedentary position and performing an activity or exercise). The patient condition may include any suitable patient state. For example, the patient condition may include a sleeping state, a wakeful state, a wakeful sedentary state, a wakeful active state, an exercise state, a breathing state, a heart rate state, or a blood pressure state.

[0122] In some examples, if at least one the feedback parameter is an upper threshold associated with a symptom, the patient condition may include the symptom (e.g., tremor, gait issues or changes, or movement problems). In some examples, the at least one feedback parameter is a lower threshold associated with onset of a side effect or overstimulation, and the patient condition may include dyskinesia. Thus, the at least one feedback parameter may be adjusted based on the patient condition. For example, if the patient condition indicates that the patient may exhibit a greater susceptibility to a side effect (e.g., an active patient may be more susceptible to a side effect compared to a sedentary patient), at least one feedback parameter that is a lower threshold value may be increased. Thus, the stimulation intensity may be modifiedDocket No.: A0012338W001 based on the increase in the lower threshold value to account for a patient condition indicative of an increased patient susceptibility to a side effect. Likewise, if the patient condition is indicative of an increased effect of stimulation on a patient symptom (e.g., a symptom of a sedentary patient may reduce at a lower stimulation intensity compared to an active patient), at least one feedback parameter that is an upper threshold value may be increased. Thus, the stimulation intensity may be modified based on the reduction in the upper threshold value to account for a patient condition indicative of an increased patient responsiveness to stimulation for reducing a symptom.

[0123] In some examples, processing circuitry 310 may adjust the at least one feedback parameter based on a patient condition alone. For example, a patient may tend to get overstimulated when the patient is in an active condition (e.g., when the patient is exercising). Thus, processing circuitry 310 may raise a single threshold to a greater magnitude if the patient condition is indicative of patient activity (e.g., exercise), to cause stimulation to be applied only when the relatively greater magnitude of the single threshold is exceeded. Alternatively, processing circuitry 310 may even terminate stimulation in response to the patient condition being indicative of high patient activity.

[0124] In some examples, the first signal includes at least one input via an external programmer (e.g., via programmer 104) or at least one sensed physiological signal (e.g., via electrodes 116 and / or 118). For example, a patient may feel a symptom, overstimulation, or an onset of side effect, and may provide an input at programmer 104 to indicate the change felt by the patient. The patient may provide an input indicating a change in patient state, for example, from a resting state to a moderately active stage (e.g., performing household chores), or to an active state (e.g., performing an exercise routine). In some examples, the patient condition includes a patient state, and processing circuitry 310 may receive the first signal from a sensor (e.g., via electrodes and sensing circuitry 204 or via telemetry module 308). For example, the sensor may indicate a prone and relatively static position of the patient, indicating rest or sleep, or a relatively dynamic patient configuration, indicating activity.

[0125] The technique may further include determining, by processing circuitry 310, based on the first signal, an adjusted value of at least one feedback parameter that at least partially defines closed-loop control of one or more stimulation parameters that define electrical stimulation therapy (804). The at least one feedback parameter may be associated with any suitable bioelectric activity. For example, the at least one feedback parameter may include a local field potential (LFP) activity or an evoked resonant neural activity (ERNA). In some examples, the at least one feedback parameter includes a power (or magnitude) of the local field potential activity within a predetermined frequency band. The predetermined frequency band may include an Alpha band, a Beta band, a Gamma band, a Delta band, or a Theta band of the local fieldDocket No.: A0012338W001 potential activity, or at least one frequency band in a range from 2 to 500 Hz. The ERNA may include a resonant peak frequency, a resonant peak frequency bandwidth, peak-to-trough amplitude of the resonant peak frequency, a count of resonant peaks, or a resonant frequency spectrum.

[0126] In some examples, processing circuitry 310 may analyze frequency bands or windows of stimulation amplitudes, and determine at least one signal that corresponds to a patient condition. For example, a patient on medication may exhibit a relatively higher change in at least one feedback parameter associated with a first frequency band, and may exhibit a relatively higher change in a second frequency band when the patient is off medication. In such examples, processing circuitry 310 may select a frequency band associated with a greatest change in sensed values of the at least one feedback parameter, and determine the adjusted value of the at least one feedback parameter associated with the selected frequency band (e.g., a power associated with the selected frequency band).

[0127] Processing circuitry 310 may determine the adjusted value of the at least one feedback parameter based on a sensed value of the at least one feedback parameter associated with a patient condition. In some examples, the patient condition may be indicative of a side effect (e.g., a sensation of pain indicated by the patient, an occurrence of a tremor indicated by the patient, dyskinesia, a fall sustained by the patient, or some other side effect). In some such examples, processing circuitry 310 sets the adjusted value of the at least one feedback parameter to be the same as the sensed value of the at least one feedback parameter associated with the patient condition. In other such examples, processing circuitry 310 sets the adjusted value of the at least one feedback parameter to be within a predetermined percentage or predetermined value relative to sensed value of the at least one feedback parameter associated with the patient condition. In some examples, setting the adjusted value of at least one feedback parameter to a percentage or value below the sensed value associated with a patient condition facilitates adjusting the intensity of stimulation to avoid the patient condition by preventing the at least one feedback parameter from reach the sensed value associated with the patient condition.

[0128] In some examples, processing circuitry 310 may analyze a plurality of sensed values associated with the patient condition, and determine a predicted threshold to avoid the patient condition. For example, processing circuitry 310 may perform a regression analysis or any appropriate statistical analysis, or use a data processing or machine learning algorithm to determine a trend in the sensed values, and determine the predicted threshold based on the trend.

[0129] In some examples, processing circuitry 310 may analyze sensed values of the at least one feedback parameter over a period of time after the patient condition to determine changes in the sensed values after the patient condition. For example, processing circuitry 310 may set theDocket No.: A0012338W001 adjusted value for the at least one parameter based on a rate of change of the at least one feedback parameter, or a maximum or minimum variation in sensed values.

[0130] Processing circuitry 310 further adjusts or modifies an adjusted value of at least one feedback parameter in response to determining that a change in a sensed value is beyond a predetermined deviation from adjusted value. For example, processing circuitry 310 may have initially set an adjusted value of the at least one feedback parameter as VI. After the adjusted value is set, processing circuitry may continue monitoring sensed values of the at least one feedback parameter, and modify the adjusted value of the feedback parameter from VI to another value V2. However, the sensed values may exhibit relatively minor departures (e.g., an increase) beyond VI. To a series of modifications to the adjusted value for relatively minor changes in sensed values of the at least one feedback parameter beyond the adjusted value VI, processing circuitry may only modify the adjusted value to V2 if a change between V2 and VI would be greater than a predetermined threshold (e.g., at least 5%, at least 10%, at least 15%, or any suitable change).

[0131] The technique may further include receiving, by processing circuitry 310, sensed information representative of a second signal sensed from the patient (806). For example, processing circuitry 310 may control sensing circuitry 204 to receive receiving sensed information representative of the second signal sensed from the patient (806). For example, the second signal may include a bioelectric signal, e.g., an LFP signal or an ERNA signal, of a patient, e.g., patient 112, sensed over a period of time (802). The period may be a period during which patient 112 is not in the clinic. For example, patient 112 may, after implantation and initial stimulation threshold setting, go home for the duration of the ambulatory period and may return to normal daily activities.

[0132] In some examples, the at least one feedback parameter is at least one threshold that is defined by a respective threshold value. In some examples (e.g., in a single threshold configuration or an inverse threshold configuration), the at least one feedback parameter consists of a single threshold value. In some such examples, the method further includes, by processing circuitry 310, in response to determining that the second signal sensed from the patient (806) is greater than or equal to the single threshold value, increasing an intensity of the electrical stimulation therapy. The stimulation intensity may refer to the “charge” or overall affect the electrical stimulation therapy has on tissue (which may or may not be perceived by the patient). In this manner, the intensity may have an instantaneous and time-based component, such as the stimulation amplitude (e.g., voltage amplitude and / or current amplitude), pulse width, and / or pulse frequency. For example, increasing any of the amplitude, pulse width, or pulse frequency, may increase the charge provided to the tissue and the overall stimulation intensity. In someDocket No.: A0012338W001 examples, the intensity may refer to one or more of amplitude, pulse width, and pulse frequency (e.g., amplitude and pulse width in one example).

[0133] In other examples, the at least one feedback parameter includes additional thresholds. For example, the at least one feedback parameter may include an upper threshold value and a lower threshold value. The upper and lower threshold values may be a magnitude or amplitude of spectral power of the sensed electrical signal (e.g., spectral power is a feature of the LFP signal). In some such examples, the method further includes increasing, by processing circuitry 310, an intensity of the electrical stimulation therapy in response to determining that the second signal sensed from the patient is greater than or equal to the upper threshold value. In some such examples, the method further includes decreasing, by processing circuitry 310, the intensity of the electrical stimulation therapy in response to determining that the second signal sensed from the patient is less than or equal to the lower threshold value.

[0134] In some examples, processing circuitry 310 may require patient confirmation of the one or more threshold values before adjusting the one or more threshold values. In this manner, user interface 302 may be configured to receive the user confirmation input and then responsively adjust the one or more threshold values. In other examples, processing circuitry 310 may adjust the one or more threshold values without patient confirmation.

[0135] The technique may further include comparing, by processing circuitry 310, the sensed information to the adjusted value of the at least one feedback parameter (810). For example, processing circuitry 310 may determine whether the sensed information is indicative of a sensed value being lower than, equal to, or greater than, the adjusted value of the at least one feedback parameter. The technique may further include controlling, by processing circuitry 310, based on the comparison of the sensed information to the adjusted value, stimulation circuitry to deliver the electrical stimulation therapy (812). For example, processing circuitry 310 may control simulation generator 202 to deliver electrical stimulation therapy according to the one or more threshold values and the sensed information. As an example, processing circuitry 310 may control stimulation generator 202 to adjust, e.g., increase or decrease, a stimulation parameter, e.g., a voltage amplitude, when a characteristic value of the sensed information meets the upper threshold value or the lower threshold value. Thus, processing circuitry 310 may control stimulation generator 202 to deliver the electrical stimulation therapy by adjusting the one or more stimulation parameters.

[0136] In some examples, processing circuitry 310 may account for a period of time (e.g., associated with waking hours, sleeping hours, sedentary hours, active hours, etc.). For example, processing circuitry 310 may receive a third signal indicative of a time period (808). Processing circuitry 310 may further modify the adjusted value based on the first signal and the third signal,Docket No.: A0012338W001 after initially determining the adjusted value based on the first signal (804). In some examples, processing circuitry 310 receives the third signal (808) before or with the first signal (802). In some such examples, processing circuitry 310 may determine the adjust value based on the first signal and the third signal. Thus, the subsequent comparison (810) and control (812) may account for the period of time or day during which the first signal indicative of the patient condition is received.

[0137] The technique may further include increasing or decreasing the intensity of the electrical stimulation based on a ramp. For example, IMD 106 may determine the ramp based on the patient condition. The ramp may be a rate of change in the stimulation amplitude. For example, the ramp may include an increase in the stimulation amplitude (positively sloped ramp). In other examples, the ramp may include a decrease in the stimulation amplitude (negatively sloped ramp). Controlling the ramp (rate of change in the stimulation amplitude) may prevent or reduce overstimulation. Thus, IMD 106 may increase or decrease the intensity of the electrical stimulation therapy at a rate based on the ramp. For example, increasing or decreasing the intensity at a rate of change exceeding the ramp may cause the electrical stimulation therapy to overshoot the thresholds, while increasing or decreasing the intensity at a rate of change conforming to the ramp may maintain the electrical stimulation therapy to within the thresholds. In some examples, the ramp may include a first ramp associated with a rate of change of an increase in intensity of the electrical stimulation therapy and a second ramp associated with a rate of change of a decrease in intensity of the electrical stimulation therapy. The first ramp may be the same as or different from the second ramp (e.g., with an opposite slope). Thus, the rate of increase in the stimulation intensity used to commence stimulation therapy (or a portion of the stimulation therapy) may be the same as or different from the rate of decrease in the stimulation intensity used to terminate the stimulation therapy (or the portion of the stimulation therapy). In this manner, IMD 106 may increase and decrease the stimulation amplitude, or another parameter, according to the respective ramp for increasing or decreasing the stimulation amplitude.

[0138] The following enumerated clauses are described herein.

[0139] Clause 1 : A system including: a memory configured to store at least one feedback parameter that at least partially defines closed-loop control of one or more stimulation parameters that define electrical stimulation therapy; and processing circuity configured to: receive a first signal indicative of a patient condition of a patient; determine, based on the first signal, an adjusted value of the at least one feedback parameter; receive sensed information representative of a second signal sensed from the patient; compare the sensed information to the adjusted value of the at least one feedback parameter; and control, based on the comparison of the sensedDocket No.: A0012338W001 information to the adjusted value, stimulation circuitry to deliver the electrical stimulation therapy.

[0140] Clause 2: The system of clause 1, where the first signal includes at least one input via an external programmer or at least one sensed physiological signal.

[0141] Clause 3 : The system of clause 1 or 2, where the at least one feedback parameter includes a local field potential activity.

[0142] Clause 4: The system of clause 3, where the at least one feedback parameter includes a power of the local field potential activity within a predetermined frequency band.

[0143] Clause 5: The system of clause 4, where the predetermined frequency band includes an Alpha band, a Beta band, a Gamma band, a Delta band, or a Theta band of the local field potential activity, or at least one band in a range of from 2 to 500 Hz.

[0144] Clause 6: The system of any one of clauses 1 to 5, where the at least one feedback parameter includes at least one threshold value.

[0145] Clause 7: The system of any one of clauses 1 to 6, where the processing circuitry is further configured to control the stimulation circuitry to deliver the electrical stimulation therapy by adjusting the one or more stimulation parameters.

[0146] Clause 8: The system of clause 6 or 7, where the at least one threshold value consists of a single threshold value, and where the processing circuitry is further configured to, in response to determining that the second signal sensed from the patient is greater than or equal to the single threshold value, increase an intensity of the electrical stimulation therapy.

[0147] Clause 9: The system of clause 8, where the processing circuitry is further configured to: determine a ramp based on the patient condition; and increase the intensity of the electrical stimulation therapy based on the ramp.

[0148] Clause 10: The system of clause 6 or 7, where the at least one threshold value includes a lower threshold value and an upper threshold value, and where the processing circuitry is further configured to: increase an intensity of the electrical stimulation therapy in response to determining that the second signal sensed from the patient is greater than or equal to the upper threshold value; and decrease the intensity of the electrical stimulation therapy in response to determining that the second signal sensed from the patient is less than or equal to the lower threshold value.

[0149] Clause 11 : The system of clause 10, where the processing circuitry is further configured to: determine a ramp based on the patient condition; and vary the intensity of the electrical stimulation therapy based on the ramp.

[0150] Clause 12: The system of any of clauses 1 to 11, where the electrical stimulation therapy includes deep brain stimulation.Docket No.: A0012338W001

[0151] Clause 13: The system of any of clauses 1 to 12, where the at least one feedback parameter includes an evoked resonant neural activity in response to the electrical stimulation therapy.

[0152] Clause 14: The system of clause 13, where the evoked resonant neural activity includes a resonant peak frequency, a resonant peak frequency bandwidth, peak-to-trough amplitude of the resonant peak frequency, a count of resonant peaks, or a resonant frequency spectrum.

[0153] Clause 15: The system of any of clauses 1 to 14, where the at least one feedback parameter includes an evoked potential neural activity in response to the electrical stimulation therapy.

[0154] Clause 16: The system of clause 15, where the evoked potential neural activity includes a peak-to-trough amplitude, a peak latency, or a trough latency.

[0155] Clause 17: An implantable medical device including the memory, the processing circuitry, and the stimulation circuitry of any of clauses 1 to Clause 16.

[0156] Clause 18: A method including, by processing circuitry: receiving a first signal indicative of a patient condition of a patient; determining, based on the first signal, an adjusted value of at least one feedback parameter that at least partially defines closed-loop control of one or more stimulation parameters that define electrical stimulation therapy; receiving sensed information representative of a second signal sensed from the patient; comparing the sensed information to the adjusted value of the at least one feedback parameter; and controlling, based on the comparison of the sensed information to the adjusted value, stimulation circuitry to deliver the electrical stimulation therapy.

[0157] Clause 19: The method of clause 18, where the first signal includes at least one input via an external programmer or at least one sensed physiological signal.

[0158] Clause 20: The method of clause 18 or 19, where the at least one feedback parameter includes a local field potential activity.

[0159] Clause 21 : The method of clause 20, where the at least one feedback parameter includes a power of the local field potential activity within a predetermined frequency band.

[0160] Clause 22: The method of clause 21, where the predetermined frequency band includes an Alpha band, a Beta band, a Gamma band, a Delta band, or a Theta band of the local field potential activity, or at least one band in a range of from 2 to 500 Hz.

[0161] Clause 23: The method of any one of clauses 18 to 22, where the at least one feedback parameter includes at least one threshold value.Docket No.: A0012338W001

[0162] Clause 24: The method of any one of clauses 18 to 23, further controlling, by the processing circuitry, the stimulation circuitry to deliver the electrical stimulation therapy by adjusting the one or more stimulation parameters.

[0163] Clause 25: The method of clause 23 or 24, where the at least one threshold value consists of a single threshold value, the method further including, by the processing circuitry, in response to determining that the second signal sensed from the patient is greater than or equal to the single threshold value, increasing an intensity of the electrical stimulation therapy.

[0164] Clause 26: The method of clause 25, further including, by the processing circuitry: determining a ramp based on the patient condition input; and increasing the intensity of the electrical stimulation therapy based on the ramp.

[0165] Clause 27: The method of clauses 23 or 24, where the at least one threshold value includes a lower threshold value and an upper threshold value, the method further including, by the processing circuitry: increasing an intensity of the electrical stimulation therapy in response to determining that the second signal sensed from the patient is greater than or equal to the upper threshold value; and decreasing the intensity of the electrical stimulation therapy in response to determining that the second signal sensed from the patient is less than or equal to the lower threshold value.

[0166] Clause 28: The method of clause 27, further including, by the processing circuitry: determining a ramp based on the patient condition; and varying the intensity of the electrical stimulation therapy based on the ramp.

[0167] Clause 29: The method of any one of clauses 18 to 28, where the electrical stimulation therapy includes deep brain stimulation.

[0168] Clause 30: The method of any of clauses 18 to 29, where the at least one feedback parameter includes an evoked resonant neural activity in response to the electrical stimulation therapy.

[0169] Clause 31 : The method of clause 30, where the evoked resonant neural activity includes a resonant peak frequency, a resonant peak frequency bandwidth, peak-to-trough amplitude of the resonant peak frequency, a count of resonant peaks, or a resonant frequency spectrum.

[0170] Clause 32: The method of any of clauses 18 to 31, where the at least one feedback parameter includes an evoked potential neural activity in response to the electrical stimulation therapy.

[0171] Clause 33: The method of claim 33, where the evoked potential neural activity includes a peak-to-trough amplitude, a peak latency, or a trough latency.Docket No.: A0012338W001

[0172] Clause 34: A system including: a memory configured to store at least one feedback parameter that at least partially defines closed-loop control of one or more stimulation parameters that define electrical stimulation therapy; and processing circuitry configured to: receive a first signal indicative of a patient condition of a patient; receive sensed information representative of a second signal sensed from the patient; receive a third signal indicative of a time period; determine, based on the first signal and the third signal, an adjusted value of the at least one feedback parameter; compare the sensed information to the adjusted value of the at least one feedback parameter; and control, based on the comparison of the sensed information to the adjusted value, stimulation circuitry to deliver the electrical stimulation therapy.

[0173] Clause 35: The system of clause 34, where the patient condition includes a sleeping state, a wakeful state, a wakeful sedentary state, a wakeful active state, an exercise state, a breathing state, a heart rate state, or a blood pressure state.

[0174] Clause 36: An implantable medical device including the memory, the processing circuitry, and the stimulation circuitry of clauses 34 or 35.

[0175] Clause 37: A method including, by processing circuitry: receiving a first signal indicative of a patient condition of a patient; receiving sensed information representative of a second signal sensed from the patient; receiving a third signal indicative of a time period; determining, based on the first signal and the third signal, an adjusted value of at least one feedback parameter that at least partially defines closed-loop control of one or more stimulation parameters that define electrical stimulation therapy; comparing the sensed information to the adjusted value of the at least one feedback parameter; and controlling, based on the comparison of the sensed information to the adjusted value, stimulation circuitry to deliver the electrical stimulation therapy.

[0176] Clause 38: The method of clause 37, where the patient condition includes a sleeping state, a wakeful state, a wakeful sedentary state, a wakeful active state, an exercise state, a breathing state, a heart rate state, or a blood pressure state.

[0177] The techniques of this disclosure may be implemented, at least in part, in hardware, software, firmware or any combination thereof. For example, various aspects of the described techniques may be implemented within one or more processors or processing circuitry, including one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or any other equivalent integrated or discrete logic circuitry, as well as any combinations of such components. The term “processor” or “processing circuitry” may generally refer to any of the foregoing logic circuitry, alone or in combination with other logic circuitry, or any other equivalent circuitry. A control unit including hardware may also perform one or more of the techniques of this disclosure.Docket No.: A0012338W001

[0178] Such hardware, software, and firmware may be implemented within the same device or within separate devices to support the various operations and functions described in this disclosure. In addition, any of the described units, circuits or components may be implemented together or separately as discrete but interoperable logic devices. Depiction of different features as circuits or units is intended to highlight different functional aspects and does not necessarily imply that such circuits or units must be realized by separate hardware or software components. Rather, functionality associated with one or more circuits or units may be performed by separate hardware or software components or integrated within common or separate hardware or software components.

[0179] The techniques described in this disclosure may also be embodied or encoded in a computer-readable medium, such as a computer-readable storage medium, containing instructions that may be described as non-transitory media. Instructions embedded or encoded in a computer-readable storage medium may cause a programmable processor, or other processor, to perform the method, e.g., when the instructions are executed. Computer readable storage media may include random access memory (RAM), read only memory (ROM), programmable read only memory (PROM), erasable programmable read only memory (EPROM), electronically erasable programmable read only memory (EEPROM), flash memory, a hard disk, a CD-ROM, a floppy disk, a cassette, magnetic media, optical media, or other computer readable media.

[0180] Various examples have been described. These and other examples are within the scope of the following claims.

Claims

Docket No.: A0012338W001WHAT IS CLAIMED IS:

1. A system comprising: a memory configured to store at least one feedback parameter that at least partially defines closed-loop control of one or more stimulation parameters that define electrical stimulation therapy; and processing circuity configured to: receive a first signal indicative of a patient condition of a patient; determine, based on the first signal, an adjusted value of the at least one feedback parameter; receive sensed information representative of a second signal sensed from the patient; compare the sensed information to the adjusted value of the at least one feedback parameter; and control, based on the comparison of the sensed information to the adjusted value, stimulation circuitry to deliver the electrical stimulation therapy.

2. The system of claim 1, wherein the first signal comprises at least one input via an external programmer or at least one sensed physiological signal.

3. The system of claim 1 or 2, wherein the at least one feedback parameter comprises a local field potential activity.

4. The system of claim 3, wherein the at least one feedback parameter comprises a power of the local field potential activity within a predetermined frequency band.

5. The system of claim 4, wherein the predetermined frequency band comprises at least one frequency band in a range from 2 to 500 Hz.

6. The system of any one of claims 1 to 5, wherein the processing circuitry is further configured to control the stimulation circuitry to deliver the electrical stimulation therapy by adjusting the one or more stimulation parameters.

7. The system of any one of claims 1 to 6, wherein the at least one feedback parameter comprises at least one threshold value.Docket No.: A0012338W0018. The system of claim 7, wherein the at least one threshold value consists of a single threshold value, and wherein the processing circuitry is further configured to, in response to determining that the second signal sensed from the patient is greater than or equal to the single threshold value, increase an intensity of the electrical stimulation therapy.

9. The system of claim 7, wherein the at least one threshold value comprises a lower threshold value and an upper threshold value, and wherein the processing circuitry is further configured to: increase an intensity of the electrical stimulation therapy in response to determining that the second signal sensed from the patient is greater than or equal to the upper threshold value; and decrease the intensity of the electrical stimulation therapy in response to determining that the second signal sensed from the patient is less than or equal to the lower threshold value.

10. The system of claim 8 or 9, wherein the processing circuitry is further configured to: determine a ramp based on the patient condition; and vary the intensity of the electrical stimulation therapy based on the ramp.

11. The system of any one of claims 1 to 10, wherein the at least one feedback parameter comprises an evoked resonant neural activity in response to the electrical stimulation therapy.

12. The system of claim 11, wherein the evoked resonant neural activity comprises a resonant peak frequency, a resonant peak frequency bandwidth, peak-to-trough amplitude of the resonant peak frequency, a count of resonant peaks, or a resonant frequency spectrum.

13. The system of any of claims 1 to 12, wherein the at least one feedback parameter comprises an evoked potential neural activity in response to the electrical stimulation therapy.

14. The system of any of claims 1 to 13, further comprising an external programming device configured to program an implantable medical device that is configured to deliver the electrical stimulation therapy, wherein the external programming device comprises the memory and the processing circuitry.

15. The system of any of claims 1 to 13, further comprising an implantable medical device configured to deliver the electrical stimulation therapy.

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