Adjustments to adaptive deep brain stimulation

Abstract

In general, devices, systems, and techniques are described for adjusting one or more parameters defining adaptive stimulation therapy. In one example, a system includes processing circuitry configured to receive sensed data indicative of bioelectric brain signals sensed during delivery of brain stimulation therapy to a patient, receive event data indicative of an event experienced by a patient during delivery of the brain stimulation therapy, identify a subset of the sensed data based on the event data, and determine, based on the subset of the sensed data and the event data, a range of values for at least one threshold defining subsequent brain stimulation therapy, the range of values determined to reduce an occurrence of the event during delivery of the subsequent brain stimulation therapy. A medical device may be controlled to deliver the subsequent brain stimulation therapy according to the at least one threshold within the range of values.

Description

Docket No.: A0011558W001ADJUSTMENTS TO ADAPTIVE DEEP BRAIN STIMULATIONCROSS-RELATED REFERENCES

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 639,401, filed April 26, 2024, the entire content of which is incorporated herein by reference.TECHNICAL FIELD

[0002] This disclosure generally relates to electrical stimulation therapy.BACKGROUND

[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).

[0004] A clinician may select values for a number of programmable parameters in order to define the electrical stimulation therapy to be delivered by the implantable stimulator to a patient. For example, the clinician may select one or more electrodes for delivery of the stimulation, a polarity of each selected electrode, a voltage or current amplitude, a pulse width, and a pulse frequency as stimulation parameters. A set of parameters, such as a set including electrode combination, electrode polarity, voltage or current amplitude, pulse width and pulse rate, may be referred to as a program in the sense that they define the electrical stimulation therapy to be delivered to the patient.Docket No.: A0011558W001SUMMARY

[0005] In general, the disclosure describes devices, systems, and techniques for automating programming and adjustment of an adaptive stimulation therapy, e.g., adaptive deep brain stimulation (aDBS), which may include monitoring brain signals, stimulation parameter values, patient events, or other aspects related to the patient and the aDBS therapy. For example, a programming device may be configured to monitor patient events and associated sensed bioelectric signals, such as brain signals, to suggest and / or select threshold values that define the adaptive stimulation therapy. In this manner, the system may leverage patient data in order to fine-tune parameters, such as threshold values, of the adaptive stimulation therapy that define how the system changes therapy over time in response to sensed signals from the patient.

[0006] In some examples, the system may be configured to present a user interface that presents information related to aDBS therapy and / or brain signal monitoring. The system may include an external programming device that communicates with a medical device and / or the medical device (e.g., an implantable medical device) configured to sense physiological signals such as electrical signals originating in the patient’s brain. The system may employ aspects of these signals for presenting information to the user and automating selection of various parameters, such as values for one or more adaptive stimulation thresholds, for subsequent sensing and / or delivering stimulation. Although aDBS is one nonlimiting example therapy, the techniques of this disclosure may be applied to many forms of adaptive stimulation therapy that may be configured to treat other conditions and / or other anatomical structures of the patient.

[0007] An external device (e.g., an external programmer) may be configured to automatically select various parameters that define sensing and / or delivering stimulation based on patient events and associated sensed physiological signals. The external device may select these parameters, or ranges for these parameter values, or present these selections to the user for approval or confirmation via a user interface. In some examples, the user interface of the external programmer may control the implant (e.g., the implantable medical device) to deliver stimulation with a varied parameter, such as varied amplitude, and sense bioelectric signals resulting from this stimulation. One example parameter defining the adaptive stimulation therapy may be one or more thresholds that, when met or exceeded, trigger the system to adjust one or more stimulation parameters that define the stimulation therapy. The system may associate identified patient events (e.g., sensed events or user input indicated events) with sensed signals (e.g., local field potentials (LFPs)) and derive aDocket No.: A0011558W001 characteristic value from this event information representative of the sensed signals. The system can then identify a suggested range of values, or even select a value, for one or more thresholds that define subsequent adaptive stimulation therapy. The system may thus more quickly identify effective adaptive therapy, such as aDBS, for the patient than more manual methods.

[0008] In one example, a system includes: receive sensed data indicative of bioelectric brain signals sensed during delivery of brain stimulation therapy to a patient; receive event data indicative of an event experienced by a patient during delivery of the brain stimulation therapy; identify a subset of the sensed data based on the event data; determine, based on the subset of the sensed data and the event data, a range of values for at least one threshold defining subsequent brain stimulation therapy, the range of values determined to reduce an occurrence of the event during delivery of the subsequent brain stimulation therapy; and control a medical device to deliver the subsequent brain stimulation therapy according to the at least one threshold within the range of values.

[0009] In another example, a method includes: receiving, by processing circuitry, sensed data indicative of bioelectric brain signals sensed during delivery of brain stimulation therapy to a patient; receiving, by the processing circuitry, event data indicative of an event experienced by a patient during delivery of the brain stimulation therapy; identifying, by the processing circuitry, a subset of the sensed data based on the event data; determining, by the processing circuitry and based on the subset of the sensed data and the event data, a range of values for at least one threshold defining subsequent brain stimulation therapy, the range of values determined to reduce an occurrence of the event during delivery of the subsequent brain stimulation therapy; and controlling, by the processing circuitry, a medical device to deliver the subsequent brain stimulation therapy according to the at least one threshold within the range of values.

[0010] In another example, a non-transitory computer-readable medium includes instructions that, when executed, control processing circuitry to: receive sensed data indicative of bioelectric brain signals sensed during delivery of brain stimulation therapy to a patient; receive event data indicative of an event experienced by a patient during delivery of the brain stimulation therapy; identify a subset of the sensed data based on the event data; determine, based on the subset of the sensed data and the event data, a range of values for at least one threshold defining subsequent brain stimulation therapy, the range of values determined to reduce an occurrence of the event during delivery of the subsequent brainDocket No.: A0011558W001 stimulation therapy; and control a medical device to deliver the subsequent brain stimulation therapy according to the at least one threshold within the range of values.

[0011] 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

[0012] 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.

[0013] 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.

[0014] 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.

[0015] FIG. 4 is a conceptual diagram illustrating an example home screen for navigating within a user interface.

[0016] FIG. 5 is a conceptual diagram illustrating an example screen for selecting an adaptive therapy mode.

[0017] FIG. 6 is a conceptual diagram illustrating an example screen for selecting one or more thresholds defining adaptive DBS (aDBS) therapy.

[0018] FIG. 7 is a flowchart illustrating an example technique for selecting an adaptive therapy mode for aDBS.

[0019] FIG. 8 is a conceptual diagram illustrating an example screen for tracking LFP power and stimulation amplitude during aDBS therapy.

[0020] FIG. 9 is a conceptual diagram illustrating an example screen displaying example event information associated with respective patent events.

[0021] FIG. 10 is a conceptual diagram illustrating an example screen displaying a single example patient event and example associated event information.

[0022] FIGS. 11 A and 1 IB are graphs of example thresholds and ranges of values determined from event information.

[0023] FIG. 12 is a flowchart illustrating an example technique for determining and displaying a range of values for one or more thresholds defining aDBS therapy.Docket No.: A0011558W001

[0024] FIG. 13 is a flowchart illustrating an example technique for selecting a value for one or more thresholds defining aDBS therapy based on event information.

[0025] FIG. 14 is a block diagram illustrating an example system that includes an external device, such as a server, and one or more computing devices that are coupled to an implantable medical device and external programmer shown in FIGS. 1 A and IB via a network.DETAILED DESCRIPTION

[0026] This disclosure describes example devices, systems, and techniques for programming adaptive stimulation therapy in which a system can automatically select one or more parameters that defines adaptive stimulation therapy based on signals sensed from 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. However, it may be time consuming for a clinician to manually determine appropriate stimulation parameters that define effective electrical stimulation therapy. Typically, a clinician may need to manually identify each parameter that defines electrical stimulation therapy. Moreover, DBS is typically delivered continuously in an open loop fashion for the patient. Not only does this open loop delivery consume more battery power due to stimulation being delivered when not needed by the patient, but a system cannot adjust stimulation parameters to provide more targeted therapy as the condition of the patient changes over time or under certain conditions. In addition, it can be challenging for clinicians to identify patient events, e.g., falls, and patient conditions and what types of adjustments could be made to improve therapy over time. Even if a system could detect an indication of these patient changes, that introduces another parameter that the clinician would need to identify as part of initial set-up of therapy and / or over the life of therapy delivery for that patient.

[0027] In a closed-loop adaptive stimulation therapy scenario, one or more parameters that define the stimulation can be automatically adjusted in response to sensed signals from the patient. For example, a sensed signal, such as an LFP signal, can be compared to one or more thresholds. In response to a characteristic value of the LFP signal (e.g., spectral power for a specific frequency or frequency band of the LFP signal) meeting or exceeding a threshold, the system may automatically adjust a stimulation parameter value (e.g., anDocket No.: A0011558W001 amplitude value) to bring that characteristic of the LFP signal back below (or above) the threshold value. In some examples, a clinician may initially select the value for one or more threshold. If two thresholds are used, this may create a “homeostatic window” for the sensed signal. Other thresholds may also be used, such as one or more limits that can define a “therapeutic window” defining acceptable stimulation parameter values (e.g., amplitude) for stimulation. For some patients, medication may be prescribed in addition to stimulation therapy. This medication can change how the patient perceives symptoms and / or responds to stimulation therapy. If the clinician initially sets threshold values when no medication is being taken, the threshold values may be inaccurate when the patient is taking medication. Threshold value determination may be more accurate when the patient is taking medication, but that may not be possible in the clinic setting or when the patient is otherwise initially fitted for therapy. The clinician and / or patient may adjust these threshold values over time, but this manual adjustment is usually a “best guess” based on subjective feedback from the patient. Moreover, the patient may not accurately convey perceived symptoms or when side effects are felt due to inappropriate stimulation settings during therapy. Even if the clinician adjusts a threshold value in the right direction, the magnitude of such threshold value change may not be appropriate and require additional adjustments over time. Over this time of manual adjustments, the patient may be experiencing therapy that is less efficacious than otherwise possible.

[0028] As described herein, various devices, systems, and techniques enable partial or fully automatic programming and management of DBS therapy and / or brain sensing for a patient. For example, systems described herein may be configured to sense and record brain signals (e.g., electroencephalogram (EEG signals), LFP signals, or other brain signals) associated with brain disorders. In some examples, the system may also determine ranges or values, or specific values, for one or more thresholds for the sensed signals and / or stimulation parameters in order to define adaptive stimulation (e.g., closed-loop therapy). The system can also display the selections and / or information corresponding to the recorded brain signals for review, selection, and / or confirmation by a user, e.g., a clinician. In some examples, the system may automatically select the one or more respective thresholds based on one or more characteristics of the recorded brain signals. In some examples, the system may receive user input specifying or adjusting the selected adaptive mode and the one or more respective thresholds.

[0029] For example, the system may track patient events that occur during the delivery of adaptive stimulation therapy and the associated sensed brain signals for those patient events.Docket No.: A0011558W001Example patient events include patient perceived unwanted symptoms and / or side effects that may occur due to inappropriate therapy (e.g., stimulation that is more intensive than needed). The system may receive user input identifying these patient events and / or automatically detect patient events by sensing signals indicative of the patient event (e.g., accelerometers indicative of patient movement, patient falls, or brain signals indicative of symptoms or side effects). The system may then also associate sensed brain signals during these periods of time corresponding to the patient events. The system can then calculate a characteristic value of the sensed brain signals and determine if the current threshold values are effective, if the threshold values need to be changed, generate a range of values for the threshold values, and / or select different threshold values based on the actual sensed signals corresponding to the patient events.

[0030] 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, the system may automatically track patient events and associated sensed signals to reduce clinician time needed to manually monitor sensed signals and find appropriate parameters by automatically using these patient events to identify threshold values for adaptive stimulation and / or other stimulation parameters that may reduce symptoms and / or side effects. The system may still present this information for the clinician to manually set threshold values that comply with these recommendations or automatically select threshold values. This process can also occur over the course of hours, days, weeks, or even longer, in order to obtain more accurate information than can be obtained just in the clinic. These automatic selections associated with aDBS may reduce expended clinician time, improve consistency of parameter selection, and improve therapeutic results for the patient by increasing therapeutic stimulation efficacy and reducing side effects.

[0031] FIG. 1 is a conceptual diagram illustrating an example system 100 that includes an implantable medical device (IMD) 106 configured to deliver adaptive deep brain stimulation to a patient 112. DBS may be adaptive (aDBS) in the sense that IMD 106 may adjust, increase, or decrease the value of one or more stimulation 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 one or more sensed signals of the patient 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 the one or more sensed signals. This process enables system 100 toDocket No.: A0011558W001 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.

[0032] Example therapy system 100 includes medical device programmer 104, implantable medical device (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 114A, 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 bioelectrical brain signals within brain 120 of patient 112. In some examples, some of electrodes 116, 118 may be configured to sense bioelectrical brain signals 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 bioelectrical brain signals and deliver adaptive electrical stimulation to brain 120.

[0033] 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 bioelectrical 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.

[0034] 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, adjusted in response to a signal deviating from a range defined by a homeostatic window (e.g., a window defined by one or more thresholds to which a brain signal is compared, such as a lower threshold and upper threshold). The homeostatic window may be used as part of an adaptive stimulation mode for adjusting stimulation therapy overDocket No.: A0011558W001 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.

[0035] In some examples, the medication taken by patient 112 is a medication for controlling one or more symptoms of Parkinson’s disease, such as tremor or rigidity due to Parkinson’s disease. Such medications include extended release forms of dopamine agonists, regular forms of dopamine agonists, controlled release forms of carbidopa / levodopa (CD / LD), regular forms of CD / LD, entacapone, rasagiline, selegiline, and amantadine. Typically, to set the upper threshold and lower threshold of the homeostatic window, the patient has been off medication, i.e., the upper and lower thresholds are set when the patient is not taking medication that is intended to reduce the symptoms. The patient may be considered to be not taking the medication when the patient, prior to the time the upper threshold is set, has not taken the medication for at least approximately 72 hours for extended release forms of dopamine agonists, the patient has not taken the medication for at least approximately 24 hours for regular forms of dopamine agonists and controlled release forms of CD / LD, and the patient has not taken the medication for at least approximately 12 hours for regular forms of CD / LD, entacapone, rasagiline, selegiline, and amantadine. If only stimulation is suppressing brain signals (e.g., LFP signals), then system 100 can measure these brain signals for various values of stimulation parameters without outside inputs. Once the upper threshold and lower threshold is established, system 100 can identify when medication wears off because the brain signals will cross the lower or upper threshold. In response to identifying the brain signal crossing a threshold, system 100 may turn on, or adjust the amplitude or intensity of, electrical stimulation to bring back brain signal amplitudes back between the lower threshold and the upper threshold to reduce symptoms once again. Programmer 104 or IMD 106 may initially set the lower threshold and the upper threshold and make adjustments to one or both thresholds over time. Programmer 104 or IMD 106 may also determine and display information regarding the amount of time stimulation amplitude is above, below, or between the thresholds. The system may be configured to determine frequencies, adaptive modes, and one or more thresholds based on bioelectric (or other) signals sensed while the patient is subjected to medication and / or not subjected to medication. Whether or not the patient is medicated may influence which adaptive mode or thresholds are used to adjust subsequent therapy.

[0036] As described herein, “reducing” or “suppressing” the symptoms of the patient refer to alleviating, in whole or in part, the severity of one or more symptoms of the patient.Docket No.: A0011558W001In one example, the clinician makes a determination of the severity of one or more symptoms of Parkinson’s disease of patient 112 with reference to the Unified Parkinson's Disease Rating Scale (UPDRS) or the Movement Disorder Society-Sponsored Revision of the Unified Parkinson’s Disease Rating Scale (MDS-UPDRS). A discussion of the application of the MDS-UPDRS is provided by Movement Disorder Society-Sponsored Revision of the Unified Parkinson’s Disease Rating Scale (MDS-UPDRS): Scale Presentation and Clinimetric Testing Results, C. Goetz et al, Movement Disorders, Vol. 23, No. 15, pp. 2129-2170 (2008), the content of which is incorporated herein in its entirety.

[0037] In some examples, system 100 may be configured to determine the upper threshold of a homeostatic window while the patient is not taking medication, and while, via HMD 106, electrical stimulation therapy is delivered to the brain 120 of patient 112. In one example, system 100 determines the point at which increasing the magnitude of one or more parameters defining the electrical stimulation therapy, such as voltage amplitude or current amplitude, begins to cause one or more side effects for the patient 112. For example, system 100 may gradually increase the magnitude of one or more parameters, such as amplitude, defining the electrical stimulation therapy and determine the point at which further increase to the magnitude of one or more parameters defining the electrical stimulation therapy causes a perceptible side effect for patient 112. As described herein, IMD 106 may sense LFPs during this process and display the LFP signal and / or LFP signal magnitude that may correspond to the respective thresholds. In this manner, system 100 may automatically determine these thresholds.

[0038] As also described herein, system 100 can also determine the lower threshold of the homeostatic window while the patient is off medication and while, via IMD 106, electrical stimulation therapy is delivered to the brain 120 of patient 112. In one example, system 100 determines the point at which decreasing the magnitude of one or more parameters, such as amplitude, defining the electrical stimulation therapy causes break-through of one or more symptoms of the patient 112. This break-through of symptoms may refer to re-emergence of at least some symptoms that were substantially suppressed up to the point of re-emergence due to the decrease in magnitude of the one or more electrical stimulation therapy parameters. For example, system 100 may gradually decrease the magnitude of one or more parameters defining the electrical stimulation therapy and determine the point at which the symptoms of Parkinson’s disease in patient 112 emerge, as measured by sudden increase with respect to tremor or rigidity, in the score of patient 112 under the UPDRS or MDS-UPDRS. In another example, system 100 measures a physiological parameter of patient 112 correlated to one orDocket No.: A0011558W001 more symptoms of the disease of patient 112 (e.g., wrist flexion of patient 112) and determines the point at which further decrease to the magnitude of one or more parameters defining the electrical stimulation therapy causes a sudden increase in the one or more symptoms of the disease of patient 112 (e.g., onset of lack of wrist flexion of patient 112). Although initial thresholds of the homeostatic window may be determined when medication is off for patient 112, threshold determination when patient 112 is taking medication may be more effective in some examples. My monitoring patient events and sensed brain signals over time that therapy is delivered, the thresholds may be selected to more appropriately account for patient consumption of medication that may not be otherwise possible via manual identification during a clinic visit.

[0039] At the magnitude of one or more parameters defining the electrical stimulation therapy at which further decrease to the magnitude of one or more parameters defining the electrical stimulation therapy causes a sudden increase in the one or more symptoms of the disease of patient 112, system 100 can measure the magnitude of the signal of the patient 112 and set this magnitude as the lower threshold of the homeostatic window. In some examples, system 100 may select a lower threshold of the homeostatic window to be a predetermined amount, e.g., 5% or 10%, higher than the magnitude at which the symptoms of the patient 112 first emerge during decrease in the magnitude of one or more electrical stimulation parameters to prevent emergence of the symptoms of the patient 112 during subsequent use.

[0040] In another example, system 100 can set a lower threshold by first ensuring that the patient is off medication for the one or more symptoms. In this example, system 100 delivers electrical stimulation having a value for the one or more parameters approximately equal to the upper threshold of the therapeutic window. In some examples, system 100 delivers electrical stimulation having a value for the one or more parameters slightly below the magnitude which induces side effects in the patient 112. Typically, this causes greater reduction of the one or more symptoms of the disease of the patient 112, and therefore greater reduction of the signal. At this magnitude of the one or more parameters, system 100 measures the magnitude of the signal of the patient 112 and sets, via external programmer 104, this magnitude as the lower threshold of the homeostatic window. In some examples, system 100 may select a value for the lower threshold of the homeostatic window to be a predetermined amount, e.g., 5% or 10%, higher than the magnitude at which the symptoms of the patient 112 emerge to prevent emergence of the symptoms of the patient 112 during subsequent use.Docket No.: A0011558W001

[0041] System 100 can monitor one or more signals of the patient for selecting one or more parameters defining stimulation and / or adjusting stimulation in a closed-loop manner. In one example, the signal is a bioelectrical signal of a patient, such as a brain signal (e.g., LFP) with a frequency within a Beta frequency band and / or a Gamma frequency band of the brain of the patient. For example, the monitored signal may be a power of the respective Beta frequency band and / or Gamma frequency band (determined based on which frequency varies during stimulation delivery and / or under the influence of medication). In yet a further example, the signal can be a signal indicative of a physiological 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 combination of different signals for initially selecting and / or adjusting one or more parameters that define subsequent stimulation therapy. System 100, via IMD 106, can be configured to deliver electrical stimulation to the patient, wherein one or more parameters defining the electrical stimulation are proportional to the magnitude of the monitored signal or adjusted in response to a magnitude of the monitored signal exceeding one or more thresholds.

[0042] 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.

[0043] In some examples, the bioelectrical signals sensed within brain 120 may reflect changes in electrical current produced by the sum of electrical potential differences acrossDocket No.: A0011558W001 brain tissue. Examples of bioelectrical brain signals include, but are not limited to, electrical signals generated from local field potentials (LFP) sensed within one or more regions of brain 120, such as an electroencephalogram (EEG) signal, or an electrocorticogram (ECoG) signal. Local field potentials, however, may include a broader genus of electrical signals within brain 120 of patient 112.

[0044] In some examples, the bioelectrical brain signals that are 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 bioelectrical brain signals. 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.

[0045] 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, 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.

[0046] 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 andDocket No.: A0011558W001 degradation from bodily fluids. IMD 106 may comprise a hermetic housing to substantially enclose components, such as a processor, therapy module, and memory.

[0047] 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. 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 implant 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.

[0048] 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.

[0049] 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.

[0050] 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 relativelyDocket No.: A0011558W001 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 may include 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.

[0051] 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.

[0052] External programmer 104 wirelessly communicates with IMD 106 as needed to provide or retrieve therapy information. Programmer 104 is an external computing device that the 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. Programmer 104 may be any type of device that is configured to communicate with IMD 106, such as a smart watch, hand-held computer, mobile device, recharger, or any other device.

[0053] 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 electrodeDocket No.: A0011558W001 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.

[0054] 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 combination 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, patient 112, or based on one or more physiological parameters of patient 112 (e.g., muscle activity, muscle tone, rigidity, tremor, etc.). Alternatively, identified patient behavior from video information may be used as feedback during the initial and subsequent programming sessions.

[0055] 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 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.

[0056] Programmer 104 may also provide an indication to patient 112 when therapy is being delivered, when patient input has triggered a change in therapy or when the power source within programmer 104 or IMD 106 needs to be replaced or recharged. For example, programmer 112 may include an alert LED, may flash a message to patient 112 via aDocket No.: A0011558W001 programmer display, generate an audible sound or somatosensory cue to confirm patient input was received, e.g., to indicate a patient state or to manually modify a therapy parameter.

[0057] 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.

[0058] 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. In other 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.

[0059] According to the techniques of the disclosure, system 100 can define a homeostatic window (e.g., one or more thresholds of an adaptive stimulation mode) 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 sensed bioelectrical signal, e.g., LFP signal, evoked resonant neural activity (ERNA), and EEG, within the homeostatic window. For example, system 100 may adjust the one or more parameters defining the electrical stimulation in response to the sensed signal falling below the lower threshold or exceeding the upper threshold 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.

[0060] In one example, external programmer 104 issues 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 (e.g., amplitude or pulse width) 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 stimulationDocket No.: A0011558W001 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. Example implementations of the therapeutic window are provided in further detail below.

[0061] Typically, a patient programmer 104 may not have access to adjustments to any thresholds or limits for sensing or stimulation related to aDBS. For example, patient programmer 104 may only enable a patient to adjust a stimulation parameter value between limits set by the clinician programmer. However, in other examples, system 100 may provide aDBS by permitting a patient 112, e.g., via a patient programmer 104, to indirectly adjust the activation, deactivation, and magnitude of the electrical stimulation by adjusting the lower and upper threshold of the homeostatic window. In one example, the patient programmer 104 may only be enabled to adjust an upper or lower threshold of the homeostatic window a small magnitude or percentage of the clinician-set value. In another example, by adjusting one or both thresholds of the homeostatic window, patient 112 may adjust the point at which the sensed signal deviates from the homeostatic window, triggering system 100 to adjust one or more parameters of the electrical stimulation within a parameter range defined by the lower and upper threshold of the therapeutic window.

[0062] In some examples, a patient may provide feedback, e.g., via programmer 104, to adjust one or both thresholds of the homeostatic window. For example, programmer 104 may provide an input mechanism where the patient can provide an input indicating when therapy is no longer effective (e.g., symptoms are detected by the patient) or a side effect is felt. Programmer 104 may then use this patient event data, and the associated sensed signals corresponding to this event, to automatically adjust a threshold of the homeostatic window and / or a bound of the therapeutic window in order to reduce the issue associated with theDocket No.: A0011558W001 patient feedback. In one examples, programmer 104 may determine a range of appropriate values for one or more thresholds within which the user can select a new threshold value, or programmer 104 may automatically select a new threshold value which may be presented for confirmation from a user. In another example, programmer 104 may re-run the threshold determination process described herein or analyze stored sensed bioelectric signals (e.g., LFP signals) and associated stimulation amplitudes to adjust one or more of the thresholds of the adaptive mode. In this manner, programmer 104 and / or IMD 106 may automatically adjust one or more thresholds of the homeostatic window based on one or more physiological or bioelectrical signals of patient 112 sensed by IMD 106 and corresponding patient events that have been identified. In response to deviations in the sensed signal of the patient outside of the homeostatic window, system 100 (e.g., IMD 106 or programmer 104) may automatically adjust one or more parameters (e.g., amplitude) defining the electrical stimulation therapy delivered to the patient in a manner that is proportional to the magnitude of the sensed signal and within the therapeutic window defining lower and upper thresholds for the one or more parameters. The adjustment to the one or more stimulation therapy parameters based on the deviation of the sensed signal may be proportional or inversely proportional to the magnitude of the signal.

[0063] Hence, in some examples, 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 one or more signals, such as sensed physiological parameters or sensed bioelectrical signals, or a combination of two or more of the above. 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.

[0064] 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 pulse width, or 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 aDocket No.: A0011558W001 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.

[0065] To adaptively adjust a parameter that defines DBS based on a bioelectrical signal, for example, two or more electrodes 116, 118 of IMD 106 may be configured to monitor a bioelectrical signal (e.g., an LFP 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 bioelectrical signal may be selected to be a signal within a Beta frequency band of brain 120 of patient 112. For example, bioelectrical signals within the Beta frequency band of patient 112 may correlate to one or more symptoms of Parkinson’s disease in patient 112. Generally, bioelectrical 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, bioelectrical signals within the Beta frequency of patient 112 increase (e.g., magnitude of the signal and / or spectral power). Moreover, bioelectrical 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, bioelectrical 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. In some examples, one or more frequencies in the Gamma band may be responsive to stimulation for some patients. This Gamma band responsiveness may come with or without Beta suppression from stimulation therapy.

[0066] In some examples, each of a sensor within IMD 106 is an accelerometer, a bonded piezoelectric crystal, a mercury switch, or a gyro. In some examples, these sensors may provide a signal that indicates a physiological parameter of the patient, which in turn varies as a function of patient activity. 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 muscularDocket No.: A0011558W001 activity of the patient. Any of these sensed signals may be used to identify a patient event that may be a symptom and / or side effect of the patient.

[0067] In some examples, the sensors generate a signal both as a function of patient activity and patient posture. For example, accelerometers, gyros, or magnetometers may generate signals that indicate both the activity and the posture of a patient 112. External programmer 104 may use such information regarding posture to determine whether external programmer 104 should perform adjustments to the therapeutic window.

[0068] For example, in order to identify posture, the sensors such as accelerometers may be oriented substantially orthogonally with respect to each other. In addition to being oriented orthogonally with respect to each other, each of the sensors used to detect the posture of a patient 112 may be substantially aligned with an axis of the body of a patient 112. When accelerometers, for example, are aligned in this manner, the magnitude and polarity of DC components of the signals generate by the accelerometers indicate the orientation of the patient relative to the Earth’s gravity, e.g., the posture of a patient 112. Further information regarding use of orthogonally aligned accelerometers to determine patient posture may be found in a commonly assigned U.S. Patent No. 5,593,431, which issued to Todd J. Sheldon, the entire content of which is incorporated by reference herein.

[0069] Other sensors that may generate a signal that indicates the posture of a patient 112 include electrodes that generate a signal as a function of electrical activity within muscles of a patient 112, e.g., an electromyogram (EMG) signal, or a bonded piezoelectric crystal that generates a signal as a function of contraction of muscles. Electrodes or bonded piezoelectric crystals may be implanted in the legs, buttocks, chest, abdomen, or back of a patient 112, and coupled to one or more of external programmer 104 and IMD 106 wirelessly or via one or more leads. Alternatively, electrodes may be integrated in a housing of the IMD 106, or piezoelectric crystals may be bonded to the housing when IMD 106 is implanted in the buttocks, chest, abdomen, or back of a patient 112. The signals generated by such sensors when implanted in these locations may vary based on the posture of a patient 112, e.g., may vary based on whether the patient is standing, sitting, or lying down.

[0070] Further, the posture of a patient 112 may affect the thoracic impedance of the patient. Consequently, sensors may include an electrode pair, including one electrode integrated with the housing of IMDs 106 and one of electrodes 116, 118, that generate a signal as a function of the thoracic impedance of a patient 112, and IMD 106 may detect the posture or posture changes of a patient 112 based on the signal. In one example (not depicted), the electrodes of the pair may be located on opposite sides of the patient’s thorax.Docket No.: A0011558W001For example, the electrode pair may include electrodes located proximate to the spine of a patient for delivery of SCS therapy, and IMD 106 with an electrode integrated in its housing may be implanted in the abdomen or chest of patient 112. As another example, IMD 106 may include electrodes implanted to detect thoracic impedance in addition to leads 114 implanted within the brain of patient 112. The posture or posture changes may affect the delivery of DBS or SCS therapy to patient 112 for the treatment of any type of bioelectrical disorder, and may also be used to detect patient sleep, as described herein.

[0071] Additionally, changes of the posture of a patient 112 may cause pressure changes with the cerebrospinal fluid (CSF) of the patient. Consequently, sensors may include pressure sensors coupled to one or more intrathecal or intracerebroventricular catheters, or pressure sensors coupled to HMDs 106 wirelessly or via one of leads 114. CSF pressure changes associated with posture changes may be particularly evident within the brain of the patient, e.g., may be particularly apparent in an intracranial pressure (ICP) waveform.

[0072] Accordingly, in some examples, instead of, or in addition to, monitoring a bioelectrical signal of the patient, system 100 monitors one or more signals from sensors indicative of a magnitude of a physiological parameter of patient 112. Upon detecting that one or more signals from sensors exceed the upper bound of a homeostatic window, system 100 increases stimulation at a maximum ramp rate determined by system 100 until one or more signals from sensors return to within the homeostatic window, or until the magnitude of the electrical stimulation reaches an upper limit of a therapeutic window determined by system 100. Similarly, upon detecting that one or more signals from sensors falls below the lower bound of the homeostatic window, system 100 decreases stimulation at a maximum ramp rate determined by system 100 until one or more signals from sensors return to within the homeostatic window, or until the magnitude of the electrical stimulation reaches a lower limit of a therapeutic window determined by system 100. Upon detecting that one or more signals from sensors are within the threshold of the homeostatic window, system 100 holds the magnitude of the electrical stimulation constant.

[0073] Such a system 100 for delivering aDBS to the patient by monitoring a physiological parameter may provide advantages over other techniques that use a bioelectrical signal as a threshold in that the techniques of the disclosure allow an IMD to control delivery of therapy using hysteresis. In other words, such a system 100 can be configured to use the physiological parameter (alone or in addition to a sensed bioelectric signal) of the patient to create a closed loop feedback algorithm for not only controlling the delivery of therapy, but also controlling the magnitude of the delivered therapy. Such aDocket No.: A0011558W001 system may be less intrusive on the activity of a patient because system 100 adapts the stimulation to the current needs of the patient, and thus may reduce the side effects that the patient experiences.

[0074] In some circumstances, system 100, as described herein, may deliver, based on the upper and lower threshold of the homeostatic window, a lower magnitude of electrical stimulation than patient 112 requires to prevent breakthrough of his or her symptoms. For example, a patient receiving therapy from an IMD 106 that controls delivery of electrical stimulation therapy using the homeostatic window may, in certain circumstances, experience results that are less optimal than if the patient received continuous electrical stimulation therapy at a maximum therapy magnitude. To prevent these occurrences, system 100 may determine a value for the at least one electrical stimulation parameter as defined by the homeostatic window, as described above. Further, the IMD 106 of system 100 may increase the value for the at least one electrical stimulation parameter by a bias amount greater than the determined magnitude defined by the homeostatic window so as to further prevent breakthrough of the symptoms of patient 112. Thus, system 100 may avoid delivering electrical stimulation therapy that is of a magnitude that may be insufficient for prevention of symptom breakthrough.

[0075] 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.

[0076] FIG. 2 is a block diagram of the example IMD 106 of FIG. 1 configured for delivering adaptive deep brain stimulation therapy. In the example shown in FIG. 2, IMD 106 includes processing circuitry 210, memory 211, stimulation generator 202, sensing module 204, switch module 206, telemetry module 208, sensor 212, and power source 220. Each of these modules may be or include electrical circuitry configured to perform the functions attributed to each respective module. For example, processing circuitry 210 may include one or more processors part of the processing circuitry, switch module 206 may include switch circuitry, sensing module 204 may include sensing circuitry, stimulation generator 202 may include stimulation generation circuitry, and telemetry module 208 may include telemetry circuitry. Switch module 204 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 anyDocket No.: A0011558W001 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. Memory 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.

[0077] In the example shown in FIG. 2, memory 211 stores therapy programs 214 and sense electrode combinations and associated stimulation electrode combinations 218 in separate memories within memory 211 or separate areas within memory 211. Each stored therapy program 214 defines a particular set of electrical stimulation parameters (e.g., a therapy parameter set), such as a stimulation electrode combination, electrode polarity, current or voltage amplitude, pulse width, and pulse rate. In some examples, individual therapy programs may be stored as a therapy group, which defines a set of therapy programs with which stimulation may be generated. The stimulation signals defined by the therapy programs of the therapy group may be delivered together on an overlapping or nonoverlapping (e.g., time-interleaved) basis. Therapy programs 214 may also store adaptive stimulation parameters that define adaptive stimulation, such as one or more thresholds for a homeostatic window and / or one or more limits for a therapeutic window. Processing circuitry 210 may directly change and / or update any of these parameter values based on commands from programmer 104, for example.

[0078] 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 may be delivered via aDocket No.: A0011558W001 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.

[0079] 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:

[0080] 1. Pulse Rate, i.e., Frequency: between approximately 40 Hertz and approximately500 Hertz, such as between approximately 40 to 185 Hertz or such as approximately 140 Hertz.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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 threshold 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.

[0085] 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 processingDocket No.: A0011558W001 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.

[0086] 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 204 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 bioelectrical brain signals 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.

[0087] 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.

[0088] 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 atDocket No.: A0011558W001 different perimeter locations around the perimeter of the lead at each of the locations A, B, C, and D. On 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.

[0089] Although sensing module 204 is incorporated into a common housing with stimulation generator 202 and processing circuitry 210 in FIG. 2, in other examples, sensing module 204 may be in a separate housing from IMD 106 and may communicate with processing circuitry 210 via wired or wireless communication techniques. Example bioelectrical brain signals include, but are not limited to, a signal generated from local field potentials (LFPs) within one or more regions of brain 28. EEG and ECoG signals are other examples of electrical signals that may be measured within brain 120 or by electrodes placed in other locations with respect to brain 120.

[0090] 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 addition, IMD 106 may receive sensor signals wirelessly from remote sensors via telemetry module 208, for example. In some examples, one or more of these remote sensors may be external to patient (e.g., carried on the external surface of the skin, attached to clothing, or otherwise positioned external to the patient). Processing circuitry 210 may identify and / or store patient events according to signals from sensor 212.

[0091] Telemetry module 208 supports 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 IMDDocket No.: A0011558W001106, 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.

[0092] Power source 220 delivers operating power to various components of IMD 106. Power source 220 may include a small 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.

[0093] According to the techniques of the disclosure, processing circuitry 210 of IMD 106 delivers, electrodes 116, 118 interposed along leads 114 (and optionally switch module 206), electrical stimulation therapy to patient 112. The aDBS therapy is defined by one or more therapy programs 214 having one or more parameters stored within memory 211 (and may specify the adaptive mode and corresponding one or more thresholds). For example, the one or more parameters 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 each 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 window 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 amplitudeDocket No.: A0011558W001 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.

[0094] In one example, processing circuitry 210, via electrodes 116, 118 of IMD 106, monitors 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 210, via electrodes 116, 118, delivers to patient 112 aDBS and may adjust one or more parameters defining the electrical stimulation within a parameter range defined by lower and upper thresholds of a therapeutic window based on the activity of the sensed signal within the homeostatic window.

[0095] In one example, the signal is a bioelectrical signal (e.g., a LFP signal) within the Beta frequency band of brain 120 of patient 112. The signal within the Beta frequency band of patient 112 may correlate to one or more symptoms of Parkinson’s disease in patient 112. Generally speaking, bioelectrical signals within the Beta frequency band 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, one or more of electrodes 116, 118 detect an increase in the magnitude of bioelectrical signals within the Beta frequency band of patient 112.

[0096] Similarly, as tremor induced by Parkinson’s disease decreases, processing circuitry 210, via the one or more of electrodes 116, 118, detects a decrease in the magnitude of the bioelectrical signals within the Beta frequency band of patient 112. In another example, the signal is a bioelectrical signal within the Gamma frequency band of brain 120 of patient 112. The signal within the Gamma frequency band of patient 112 may also correlate to one or more side effects of the electrical stimulation therapy. However, in contrast to bioelectrical signals within the Beta frequency band, generally speaking, bioelectrical signals within the Gamma frequency band of patient 112 may be approximately inversely proportional to the severity of the side effects of the electrical stimulation therapy. For example, as side effects due to electrical stimulation therapy increase, processing circuitry 210, via the one or more of electrodes 116, 118, detects a decrease in the magnitude of the signal within the Gamma frequency band of patient 112. Similarly, as side effects due to electrical stimulation therapy decrease, processing circuitry 210, via the one or more of electrodes 116, 118, detects an increase in the magnitude of the signal within the Gamma frequency band of patient 112.

[0097] In response to detecting that the signal of the patient, e.g., a sensed bioelectrical signal, has deviated from the homeostatic window, processing circuitry 210 dynamically adjusts the magnitude of the one or more parameters of the electrical stimulation therapy such as, e.g., pulse current amplitude or pulse voltage amplitude, to drive the signal of the patientDocket No.: A0011558W001 back into the homeostatic window. For example, wherein the signal is a bioelectrical signal within the Beta frequency band of brain 120 of patient 112, processing circuitry 210, via the one or more of electrodes 116, 118, monitors the Beta magnitude of patient 112. Upon detecting that the Beta magnitude of patient 112 exceeds the upper bound of the homeostatic window, processing circuitry 210 increases a magnitude of the electrical stimulation delivered via electrodes 116, 118 at a maximum ramp rate, e.g., determined automatically or by the clinician until the magnitude of the bioelectrical signal within the Beta band falls back to within the homeostatic window, or until the magnitude of the electrical stimulation reaches an upper limit of a therapeutic window determined by system 100 (FIG. 1). Similarly, upon detecting that the Beta magnitude of patient 112 falls below the lower bound of the homeostatic window, processing circuitry 210 decreases stimulation magnitude at a maximum ramp rate determined by system 100 until the Beta magnitude rises back to within the homeostatic window, or until the magnitude of the electrical stimulation reaches a lower limit of a therapeutic window determined by system 100. Upon detecting that the Beta magnitude is presently within the threshold of the homeostatic window or has returned to within the threshold of the homeostatic window, processing circuitry 210 holds the magnitude of the electrical stimulation constant. In other examples, processing 210 may automatically determine the ramp rate at which stimulation parameters are adjusted to cause the brain signal to fall back within the target range. The ramp rate may be selected based on prior data indicating general patient comfort or comfort or preferences of the specific patient.

[0098] In some examples, processing circuitry 210 continuously measures the signal in 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 of approximately 150 Hertz.

[0099] 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 the brain signal has 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. For example, 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 bringDocket No.: A0011558W001 the signal back down below the upper threshold. 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.

[0100] In another example, in response to detecting that the signal has fallen below a lower threshold of the homeostatic window and prior to delivering the electrical stimulation 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 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.

[0101] 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).

[0102] In another example, values defining the therapeutic window are stored within a memory 311 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. In one example, 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.

[0103] In another example, processing circuitry 210, via telemetry module 208 and from external programmer 104, receives instructions to adjust one or more limits of the therapeuticDocket No.: A0011558W001 window. For example, such instructions may be in response to patient feedback on the efficacy of the electrical stimulation therapy, or in response to one or more sensors that have detected a signal of the patient. Such signals from sensors may include bioelectrical signals, such as a signal within the Beta frequency band or signal within the Gamma frequency band of brain 120 of patient 112, or physiological parameters and measurements, such as a signal indicating one or more of a patient activity level, posture, and respiratory function. Further, such signals from sensors may indicate a lack of reduction of one or more symptoms of the patient 112, such as tremor or rigidity or the presence of side effects due to electrical stimulation therapy, such as paresthesia. In response to these instructions, processing circuitry 210 may adjust one or more thresholds of the homeostatic window. For example, processing circuitry 210 may adjust the magnitude of the upper threshold, the lower threshold, or shift the overall position of the homeostatic window such that the threshold, defined by the homeostatic window, for adjustment of the one or more parameters of electrical stimulation, is itself adjusted. Thereafter, processing circuitry 210, via electrodes 116 and 118, delivers the adjusted electrical stimulation to patient 112.

[0104] 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. 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.

[0105] 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, which may include fixed function processing circuitry and / or programmable processing circuitry, as formed by, for example, one or more microprocessors, DSPs, ASICs,Docket No.: A0011558W001FPGAs, 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, a 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.

[0106] 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 obtain a parameter set from memory, 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.

[0107] 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 user input may be, for example, in the form of pressing a button on a keypad or selecting an icon from a touch screen. The user input may indicate that a patient event has occurred, and may, in some examples, indicate the type of patient event (e.g., a symptom occurred, a side effect occurred, or any other type of patient event). In some examples, processing circuitry 310 may time stamp this patient event to correlate with sensed signals later retrieved from IMD 106. In some examples, processing circuitry 310 may transmit the indication of the patient event to IMD 106 to associate the patient event and store sensed signals and / or immediately request the sensed signals from IMD 106 for association with the patient event and storage inDocket No.: A0011558W001 memory 311 for further processing. 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.

[0108] Telemetry module 308 may support wireless communication between IMD 106 and programmer 104 under the control of processing circuitry 310. Telemetry module 308 may also 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.

[0109] 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.

[0110] According to the techniques of the disclosure, in some examples, processing circuitry 310 of external programmer 104 defines the parameters of a homeostatic therapeutic window, stored in memory 311, for delivering aDBS 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 via leads 114.[oni] The following examples illustrate various user interfaces and techniques for managing the sensing of physiological signals, such as brain 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 interface screens may be separately presented orDocket No.: A0011558W001 selectable in any order, or programmer 106 (for example) may present each screen in order as part of one or more automated programming processes to assist the user through the programming process for setting up or adjusting adaptive stimulation therapy. 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.

[0112] FIG. 4 is a conceptual diagram illustrating an example home screen 402 for navigating within an example user interface 400. User interface 400 may include several different screens as the user can navigate to different functions to view sensed information, view stored data, or determine 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 battery 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. Example alerts may include an aspect of the system that is out of specification or one or more aspects related to stimulation that still need to be completed so that therapy can be delivered to patient 112.

[0113] 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. Selection of each item in menu 408 may case user interface 400 to present one or more screens associated with that portion of the user interface. Once within one screen of userDocket No.: A0011558W001 interface 400, user interface 400 may continue to guide the user through the rest of therapy setup from that point. However, the user may jump between different screens as desired by selecting different functions from various menus within each screen of user interface 400.

[0114] 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 button 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.

[0115] 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 (e.g., patient 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.

[0116] User interface 400 may enable the system to automatically determine various parameters related to adaptive stimulation therapy. In some examples, system 100 may use user input provided via user interface 400 to initiate automated process related to this parameter selection, provide recommended parameters for user confirmation, present sensed data, or other enable the user to manage stimulation therapy. Therefore, user interface 400 provided by programmer 106 or another external device may provide automated sensing of bioelectric signals, selecting one or more thresholds for the adaptive mode, parameter thresholds for stimulation, and / or any other selectable parameters related to closed-loop adaptive stimulation therapy. In some examples, the automated process may perform all of these processes and display recommended parameters and modes at a single final screen forDocket No.: A0011558W001 user confirmation. In some examples, user interface 400 may present a screen after each parameter selection step with recommended parameter values, or recommended range of values, for the user to confirm or select from before moving to the next step. In other examples, system 100 may present automated recommendations for selectable parameters in each step via user interface 400 as the user moves through different screens of user interface 400. In this manner, the user can obtain the system recommended parameter values available to avoid manual selection. In any event, user interface 400 may provide the automated process with one or more opportunities for the user to review, confirm, and / or change the automated parameter value or other selections. In some examples, the user may return to any of these screens in follow up visits with the patient during the course of therapy over time.

[0117] As described herein, system 100 may enable automated selection of one or more parameters related to adaptive stimulation therapy that utilizes one or more feedback variables for closed-loop therapy. One example type of adaptive therapy is aDBS, but other types of therapies may similarly enable automatic adjustments based on one or more sensed signals from the patient. In one example, system 100 includes a memory and processing circuity, such as processing circuitry 210, processing circuitry 310, or processing circuitry from other device or any combination thereof. Processing circuity 310 of programmer 106 will generally be described herein as one example, but other circuitry, devices, or combinations thereof may perform similar functions. Processing circuitry 310 may be coupled to the memory and configured to control sensing circuitry (e.g., sensing circuitry of sensing module 204) to sense a plurality of bioelectric signals from a brain of the patient via a plurality of different electrode combinations. Processing circuity 310 may also receive information representative of the plurality of bioelectric signals (e.g., data that represents the sensed voltage over time between the electrodes of the electrode combination), and determine spectral power information from the information representative of the plurality of bioelectric signals. Processing circuity 310, or another processor, may perform a Fast Fourier Transform (FFT) to transform the voltage information from the time domain into the frequency domain. From this spectral power information, processing circuity 310 may determine a characteristic, such as a power characteristic, that may be representative of the sensed signal at a particular frequency or frequency band. This characteristic may normalize the sensed signal to an indication of the physiological condition at that time.

[0118] Memory 311 may include threshold determination instructions. These threshold determination instructions may determine how processing circuitry 310 determines values, or ranges of values, for one or more thresholds based on sensed signals. Processing circuitryDocket No.: A0011558W001310 may be configured to receive event information representing sensed bioelectric brain signals corresponding to one or more patient events identified during delivery of adaptive deep brain stimulation therapy to a patient. In this manner, the event information may include the sensed brain signals and / or characteristics representative of the brain signals, such as a power characteristic. Processing circuitry 310 can then determine, according to the event information and the threshold determination instructions, a range of values for at least one threshold defining adaptive deep brain stimulation therapy. This range of values can be determined to reduce an occurrence of the one or more patient events during delivery of subsequent adaptive deep brain stimulation therapy. For example, if the event information indicates that a symptom has occurred even though the sensed signal did not exceed a threshold, processing circuitry 310 can determine a range of values that may be more appropriate for adjusting the threshold to a new value at which the symptom would no longer occur. The range of values may be an actual range, or a suggested threshold minimum or maximum that establishes that the selected value for the threshold should be at or above the minimum or at or below the maximum suggested threshold.

[0119] Using these adaptive stimulation parameters, such as a threshold value within the range of values, processing circuity 310 can control deep brain electrical stimulation therapy according to the one or more thresholds and the subsequently sensed bioelectric signals via the one electrode combination. Processing circuity 310 may present the selected parameters to a user via user interface 400 for confirmation from the user before initiating therapy using the parameters. Processing circuity 310 may also control the selected parameters to be transmitted to IMD 104 for use in stimulation therapy as a part of controlling the stimulation therapy.

[0120] In some examples, the patient event may include at least one of a symptom occurrence or a side effect occurrence. The symptom or event may include patient feelings, patient movements, falls, slurred speech, dyskinesia, or any other aspects that may be associated with the patient’s condition and / or inappropriate therapy. Therefore, patient events may generally be associated with ineffective therapy. However, in some examples, patient events may be positive therapy indications that processing circuitry 310 may use to reinforce appropriate threshold values, for example.

[0121] The sensed bioelectric brain signal can be a local field potential (LFP) signal, and the information representing the sensed brain signal can include a characteristic value indicative of a power of the LFP signal. In some examples, processing circuitry 310 can be configured to calculate the characteristic value by at least determining a spectral power valueDocket No.: A0011558W001 of the LFP signal for each time period of a plurality of time periods and summing the spectral power from each time period of the plurality of time periods to calculate a total power corresponding to the patient event, the total power being the characteristic value. In this manner, processing circuitry 310 may establish multiple “bins” of time over the time period of the patient event and calculate the characteristic value of the signal for each bin. This segmentation may enable processing circuitry 310 to compare different patient events to each other and identify appropriate threshold values to use for subsequent adaptive therapy.

[0122] In some examples, processing circuitry 310 may automatically determine, according to the event information and the threshold determination instructions, a value within the range of values for the at least one threshold. For example, processing circuitry 310 may calculate an appropriate value for the threshold that falls within the range. The appropriate value may be the same as a minimum or maximum threshold of the range, or may be set to a percentage of the minimum or maximum threshold or at a predetermined offset from the minimum or maximum threshold. In this manner, processing circuitry 310 may be configured to identify threshold values that may be effective based on the range of values.

[0123] In other examples, processing circuitry 310 may prompt a user to select a value for a threshold within the range of values. For example, processing circuitry 310 may control a display device of programmer 104 to present the range of values via a user interface (e.g., user interface 302 or 400). Processing circuitry 310 may then receive, via the user interface, user input selecting a value within the range. For example, the selection of the value may be a user inputting a numerical value, user movement of a slider to a numerical position within the range, or some other user input specifying the desired value for the one or more thresholds. Processing circuitry 310 can then control IMD 106 to deliver the subsequent adaptive deep brain stimulation therapy according to the value of the at least one threshold. In this examples, the one or more threshold includes an upper threshold and a lower threshold (e.g., of a homeostatic window) that define the adaptive deep brain stimulation therapy and the subsequent adaptive deep brain stimulation therapy. In some examples, the user input may specify each threshold independently. In other examples, the user may determine the thresholds together to keep a desired range of the window while changing the lower and upper values together. In some examples, processing circuitry 310 may automatically determine one or more limits of a stimulation parameter (e.g., an amplitude and / or therapeutic window) based on the event information. For example, based on the sensed signals and / or amplitudes used during adaptive stimulation therapy, processing circuitry 310 may increase or decrease one or more of the limits in order to reduce the occurrence of another patientDocket No.: A0011558W001 event. In some examples, processing circuitry 310 may present the user interface to present an input field in which the user can adjust the one or more limits based on the changes to the thresholds, an automatically generated suggestion of limits or range of limits, and / or presented stimulation parameter data during the patient event. Processing circuitry 310 may then receive user input specifying the updated limit to the stimulation parameter.

[0124] Processing circuity 310, or processing circuitry of another device, may be configured to control stimulation by directly instructing changes to stimulation based on sensed signals. In some examples, processing circuity 310 may control stimulation by controlling telemetry circuitry to transmit instructions, such as the frequency and the one or more threshold values, to IMD 104 for controlling delivery of the deep brain electrical stimulation.

[0125] System 100 may determine various parameters automatically or with user input. These parameters may include a sensing electrode combination of a lead and the frequency that will be used to monitor sensed signals, such as in the frequency domain. A sensing electrode combination and frequency for sensing may be determined from initial LFP data obtained from the patient.

[0126] FIG. 5 is a conceptual diagram illustrating an example screen 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. 5, user interface 400 may include a screen 502 that indicates the automated or manual system selection of dual threshold mode 506, single threshold mode 508, or single threshold inverse mode 510. Dual threshold mode 506 is shown as selected. Dual threshold mode 506 enables the system to adjust stimulation amplitude based on upper and lower thresholds of the LFP signals. Single threshold mode 508 enables the system to increase stimulation when LFP signals are above the threshold, and single threshold inverse mode 510 enables the system to decrease stimulation when LFP signals are below the threshold.

[0127] Processing circuitry 310 may automatically determine which adaptive mode to use based on the sensed bioelectric signals and patient events. For example, processing circuitry 310 may identify whether a current adaptive mode is adequately treating the patient. Based on the patient events and sensed signals during those events, processing circuitry 310 may select a different adaptive mode. This may be due to changes in a progression of patient disease or changes in a frequency band that is most effective at treating patient symptoms. For example, if patent events, such as symptoms, are still occurring with large amplitudes of stimulation based on beta signals, processing circuitry 310 may determine that gamma signalsDocket No.: A0011558W001 may be tracked using a single threshold inverse mode 510 instead, for example. In some examples, processing circuitry 310 may suggest a mode to select and require the user to provide user input confirming the suggestion. In other examples, the user may select the desired mode and processing circuitry 310 may receive the user input selecting that mode via screen 502.

[0128] FIG. 6 is a conceptual diagram illustrating an example screen 600 for selecting one or more thresholds defining aDBS therapy. Screen 600 of user interface 400 may be presented to select initial threshold values and / or to modify threshold values during therapy. As shown in the example of FIG. 6, a representation of a lead and the electrodes carried thereon is displayed in screen 600. The cathode and anode electrodes are also indicated to show the selected electrode configuration as part of lead view 604. The menu indicates that lead view 604 is currently displayed, but that annotation of the electrode configuration 602 can be shown instead. To the right of the lead view 604, an LFP graph 606 and a stimulation parameter graph 608 are displayed. A capture button enables the user to request capture of the LFP at the current amplitude. On the very right of the screen 600 is parameter view 614 which includes inputs selectable by the user to increase (button 618) and decrease (button 620) the stimulation parameter, which is current amplitude in the example of FIG. 6. Button 616 jumps to the upper amplitude limit that has been set. Button 622 jumps to the lower amplitude limit when set. Parameter buttons (not shown) enable the user to select the desired parameter, such as amplitude, pulse width, or frequency, to adjust. On this screen of FIG. 6, the user may set parameter value limits that correspond to respective thresholds for the brain signal, such as LFPs, by sliding or moving using upper threshold 634 and lower threshold 636. Passive sensing button 640 causes programmer 104 to save the LFP values for sensing only, instead of adaptive stimulation. The user can move between different screens of user interface 400 via previous button 512 and next button 514.

[0129] Using screen 600 of user interface 400, the user can capture thresholds of the LFP that correspond to respective stimulation parameter values or otherwise set initial thresholds using upper threshold 634 and / or lower threshold 636. In this manner, the system can determine a LFP Classification threshold using stimulation as the actuator. In one example, each threshold may be set based on measuring LFPs for 25 seconds at particular amplitude levels as defined by the patient’s tolerance and symptom relief. Other durations of sensing may be used in other examples.

[0130] Typically, to set the upper threshold and lower threshold for brain signal monitoring, the patient has been off medication, i.e., the upper and lower thresholds are setDocket No.: A0011558W001 when the patient is not taking medication selected to reduce the symptoms. The patient may be considered to be not taking the medication when the patient, prior to the time the upper bound is set, has not taken the medication for at least approximately 72 hours for extended release forms of dopamine agonists, the patient has not taken the medication for at least approximately 24 hours for regular forms of dopamine agonists and controlled release forms of CD / LD, and the patient has not taken the medication for at least approximately 12 hours for regular forms of CD / LD, entacapone, rasagiline, selegiline, and amantadine. If only stimulation is suppressing brain signals (e.g., LFP signals), then the system can measure these brain signals for various values of stimulation parameters without outside inputs. Once the upper threshold and lower threshold is established, the system can identify when medication wears off because the brain signals will cross the lower or upper threshold. In response to identifying the brain signal crossing a threshold, the system may turn on electrical stimulation to bring back brain signal amplitudes back between the lower threshold and the upper threshold. Thresholds may be set for certain brain signals, such as signals within the Beta frequency band, when the patient is off medication. In some examples, such as when assessing signals within the Gamma frequency band, thresholds may be set when the patient is on medication. In other examples, a patient with medication may be evaluated and thresholds set.

[0131] When the patient is not getting any medication, LFP activity may be present above a threshold, such as greater than or equal to 1 ,2uVp. In this procedure, the user will identify the lowest current amplitude where symptoms are controlled, which will correlate to the upper threshold for the LFP signal. Slider 626 may be selected and dragged by the user to increase or decrease the amplitude of stimulation. This lowest amplitude will also be set as the lower limit for the stimulation parameter.

[0132] As shown in FIG. 6, screen 600 indicates that the upper threshold 634 has been set and color coordinated to the lower limit for current amplitude (e.g., shown as the same color). The lower threshold 636 has been set and color coordinated to the upper limit for current amplitude (e.g., shown as the same color different from the upper threshold / lower limit color). In addition to color, the upper threshold 634 and lower limit has a similar pointing arrow, while the lower threshold 636 and the upper limit has a similar pointing arrow. In this manner, the system can adjust the current amplitude automatically between the lower and upper limit in order to maintain the LFP signal between the lower and upper thresholds.

[0133] As shown herein, increasing current amplitude (or other stimulation parameters that increase stimulation intensity) may decrease the amplitude of the LFP signal at theDocket No.: A0011558W001 selected frequency. Conversely, decreasing current amplitude (or other stimulation parameters that decrease stimulation intensity) may increase the amplitude of the LFP signal at the selected frequency. LFPs below the lower threshold may indicate that the patient is receiving too much stimulation and having dyskinesia, while LFPs above the upper threshold may indicate that the patient’s symptoms are not being controlled effectively. In some examples, the average power for the selected frequency over 30 seconds is captured as the upper threshold and the lower threshold. In some examples, processing circuitry 310 may employ error checking on the upper and lower thresholds. For example, processing circuitry 310 may reject capturing a threshold if that capture would result in the upper threshold being below the lower threshold. In addition, or alternatively, processing circuitry may perform a statistical threshold check to ensure that the thresholds are adequately separated from one another.

[0134] As shown in FIG. 6, the system can capture LFPs during delivery of stimulation. This may be possible because the stimulation electrodes are different from the sensing electrodes. One benefit to this capability of capturing LFPs while delivering stimulation is that the LFP data may be identified when the patient is home so that the system can monitor the LFP thresholds. As described herein, patient events may be tracked over time and sensed signals used to determine any changes to the thresholds over time.

[0135] FIG. 7 is a flowchart illustrating an example technique for selecting an adaptive therapy mode for aDBS. The process of FIG. 7 may describe manual determination of initial thresholds. However, this process may be repeated during therapy to update appropriate threshold values or to confirm system suggested values or from ranges of values. In the example of FIG. 7, processing circuitry 310 receives user input requesting setting of thresholds for adaptive DBS (702). Processing circuitry 310 then captures the upper threshold of the LFP brain signal at the lower limit of stimulation amplitude that reduces symptoms for the patient (704). Processing circuitry 310 then increases stimulation amplitude according to user input (706). Processing circuitry 310 captures the lower threshold of the LFP brain signal at the upper limit of stimulation amplitude that is just below side effects for the patient (708). Processing circuitry 310 then stores the thresholds and limits for adaptive DBS (710). The user may adjust these thresholds and limits manually in some examples.

[0136] In some examples, these threshold values may be initial values determined in order for the patient to start receiving aDBS therapy. During this initial period of time, or throughout therapy, the system may identify patent events, such as symptom and side effectDocket No.: A0011558W001 occurrences indicating that aDBS could be more effective, and corresponding sensed signals. As described herein, the system (e.g., programmer 104 and / or IMD 106) may determine ranges of values (or even specific threshold values) that may be more effective at treating the patient according to the event information that includes the patient events and sensed signal information. The initial period of time to evaluate therapy, such as a trial period, may be set to the order of days, weeks, or even months of normal patient routine using aDBS therapy. Evaluation of event information for further updates to threshold values, for example, may continue periodically or on demand during the course of therapy for the patient.

[0137] FIG. 8 is a conceptual diagram illustrating an example screen 800 for tracking LFP power and stimulation amplitude during aDBS therapy. Screen 800 may present data such as event information that may include patient events, sensed signal data and / or characteristics, and / or stimulation parameter values (e.g., amplitude of stimulation corresponding to sensed signals). Screen 800 may also enable a user to request auto selection of new thresholds (or ranges of values for thresholds) for the adaptive mode based on stored event information. System 100 may store identified patient events (e.g., symptoms and side effects) sensed LFP signals and stimulation amplitude values over time during therapy for the patient. This monitoring may be beneficial based on longitudinal (chronic) monitoring of the most common peaks observed during patient events over time in which patient 112 has received therapy. Processing circuitry 310 monitors bioelectrical signal, e.g., LFP, over time and depicts an associated power of the signal, e.g., an LFP power or LSB value, as a trace 814. In some examples, this data will be stored continuously. In other examples, this data will be stored for a time period corresponding to respective identified patient events (e.g., system detected events or user indicated events). In some examples, trace 814 is presented in conjunction with a current amplitude 816 of stimulation pulses delivered over the same time. Hemisphere selector 808 allows the user to switch between signals sensed from different leads in respective hemispheres, and time selector allows the user to switch between different periods of time to show data corresponding to the different periods. The user may additionally select various timelines within the different periods, e.g., days of the month or different patient events, using timeline 812. Medication indicator on 804 and off 806 indicates whether the patient was under the influence of medication during the time of the stored data.

[0138] LFP and stimulation amplitudes may be sampled at a specific rate, e.g., six times per hour, or in response to the identification of specific patient events. However, higher or lower sample rates may be used depending on data storage capabilities. During a clinic visit,Docket No.: A0011558W001 e.g., a post-implantation follow-up visit, user interface 400 may present screen 800 and a snapshot 818 of bioelectrical signal information, e.g., LFP peaks or LSB value, stored at the same time of a patient event for clinician review. In some examples, user interface 400 may present multiple snapshots of LFP peaks. The user may select the box of snapshot 818 to make adjustments such as choosing a different threshold using that patient event and / or other events. In other examples, processing circuitry 310 may provide an indication that the event information prompt the user to confirm a new suggested frequency for monitoring.

[0139] Screen 800 may display auto selection button 820 to trigger processing circuitry 310 to re-analyze the data, such as event information, to determine a range of values (or even a specific selected value) for the one or more thresholds that should be used for subsequent use of the adaptive mode. In this manner, the system can re-identify the appropriate thresholds suing the sensed signals during patient events. In some examples, the system may also adjust the stimulation parameter limits at the same time based on the same data. Although screen 800 indicates the user prompts the analysis of stored sensed signals for adjusting the thresholds of the adaptive mode, processing circuitry 310 may automatically trigger the re-determination of thresholds based on any triggering event, such as unresponsive LFP signals to changes in stimulation, user input indicating ineffective therapy, or even sensed patient events using physiological signals (e.g., patient movements, postures, falls, etc.) that may indicate that therapy is not effective at treating patient symptoms.

[0140] Processing circuitry 310 may then control delivery of subsequent deep brain electrical stimulation according to updated or adjusted one or more threshold values. In any case, processing circuity 310 may periodically adjust one or more parameters (e.g., electrode combination, sensing frequency, adaptive mode, adaptive thresholds, stimulation thresholds, etc.) that define adaptive stimulation to maintain therapy efficacy. The user may close screen 800 using close button 822 to also store these settings. 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. Although FIG. 8 is described as providing sensed data that was sensed during stimulation delivery, the sensed data may be sensed as stimulation is delivered or during an active stimulation period but actual stimulation delivery does not overlap with the sensed data or the detected event data. In some examples, the system may sense data and / or events during periods of time in which stimulation therapy is not provided or even separate from any therapy delivery.Docket No.: A0011558W001

[0141] FIG. 9 is a conceptual diagram illustrating an example screen 900 displaying example event information associated with respective patent events. FIG. 9 illustrates a screen 900 showing patient events and corresponding LFP information displayed on a graph 906 of LFP power vs. frequency. Traces 912 are the LFP powers for each event shown in event list 914, but other characteristic values of the sensed signals, such as different scaled powers (e.g., LSB) may be calculated and displayed in other examples. Hemisphere selector 902 can be selected to switch between signals sensed from different leads, and range selector 904 can be selected to switch between different periods of time for patient events. Although four event types are shown as selectable in this example, fewer or greater types of events may be indicated by the user in other examples. The screen 900 of FIG. 9 provides a slider 910 that the user can move to adjust frequency bar 908 and identify the frequency and / or power of any part of each trace. On the right of the screen 900, the event list 914 of each event is provided. In response to the user deselecting an event (e.g., by unchecking the respective check box), user interface 400 will remove that specific trace for that event from the graph 906. In this manner, the user can choose to evaluate any events and compare any events. In some examples, the user can select which patient events to use in determining the range or values or specific values for thresholds. For example, the user can remove any patient events that the user does not want to include in the determination of the updated threshold values. In other examples, other types of information could be captured for each event, such as medication status, accelerometer data, stimulation delivery status, etc. Each of these types of information may be presented on the same graph or different graphs for each type of information. Selection of close button 918 will close screen 900.

[0142] FIG. 10 is a conceptual diagram illustrating an example screen 1000 displaying a single example patient event and example associated event information. FIG. 10 illustrates an example screen 1000 in which a dyskinesia event was identified and the corresponding trace 1004 is shown in graph 1002. In some examples, programmer 104 may automatically place frequency bar 908 at the peak in frequency, but the user can always move slider 910 to the peak on trace 1004. Using screen 1000, the user may be able to review specific event information for specific patient events and update various parameters or review specific information used in updating threshold values. In this example, dyskinesia may be a side effect of stimulation, and the user may desire to review the power of the sensed signal and / or frequency that corresponds to sensing this side effect.

[0143] FIGS. 11 A and 1 IB are graphs of example thresholds and ranges of values determined from event information. As shown in the example of FIG. 11 A, initial thresholdsDocket No.: A0011558W001 are shown in graph 1100. For example, upper threshold 1104 is shown in relation to lower threshold 1102. Together, upper threshold 1104 and lower threshold 1102 may correspond to a homeostatic window that may be used by IMD 106 to deliver aDBS therapy to the patient. The values of upper threshold 1104 and lower threshold 1102 are shown in “LSB”, which is a characteristic of sensed LFP signals.

[0144] The LSB value may be calculated to provide a consistent characteristic representative of the power of sensed LFP values at any given time. The LSB value may be similar to the LFP spectral power. However, the LSB value may be calculated by averaging LFP power over multiple periods of time (e.g., a “bin” of predetermined period of time) and then summing that power to provide a representative power over the duration of the multiple periods of time. This LSB value may then normalize the LFP signal over a portion of time that can be compared to other portions of time. This LSB value over the portion of time may better represent clinically relevant power of the LFP signal than a maximum LFP power at an instance in time, for example.

[0145] One example method of calculating the LSB (e.g., a characteristic value of the sensed LFP signal) may be calculated by equation (1) below:ADC = LFP power ((Gain x 215 57) / 120000) (1) where the ADC is a scaled value from the LFP power which may have units such as pVp in some examples. The Gain may be calculated in one specific example according to equation (2) below:Gain = 250 x ((INS trim per channel) / (255)) (2) where the INS trim per channel may be a specific offset for the sensing channel which may vary for different devices or different channels. The Gain can this be calibrated as needed. The system can then calculate the ADC value for each bin (e.g., each period of time for which the LFP power was calculated). Then, the system may sum all of the bins corresponding to the patient event in order to determine that LSB value for that LFP snapshot corresponding to the patient event.

[0146] The duration of time for each LFP snapshot of a patient event may be predetermined. In one example, the duration may be set to 30 seconds, but shorter durationsDocket No.: A0011558W001 of 10 seconds or less may be used in some examples or durations of a few minutes or longer may be used in other examples. The time period of each bin may also be predetermined. In some examples, a bin may include the sensed LFP power for a certain period of time. An example bin may have a 6 second length, such that 5 bins may be used to achieve the 30 second duration of the LFP snapshot. However, shorter or longer duration bins, and fewer or more bins, may be used in other examples. In any case, the system may set the durations and numbers of bins for one patient to enable the system to compare LSB values to different patient events and over the duration of therapy.

[0147] The LFP signals corresponding to a patient event may be the LFP signals that occur after the patient event is identified, LFP signals that are sensed before and after the patient event, or LFP signals sensed prior to the patient event. Looking backward in time for LFP signals may be important for situations in which the patient event begins prior to sensed data indicates the patient event or the user can input the indication that the patient event is occurring. In this manner, the system may store LFP signals in a buffer and store a certain period of LFP signals that previously occurred in response to detecting the patient event.

[0148] Data below is provided as an illustration of determining a new range of values for respective thresholds. Table 1 below indicates symptom patient events for the left side of the body which correspond to sensed brain signals in the right hemisphere. The left column indicates the specific patient event, and the right column indicates the computed LSB value from the LFP snapshot associated with the patient event.Table 1.Docket No.: A0011558W001

[0149] As shown above in Table 1, the lowest three LSB values average to an LSB value of 970. This LSB value corresponds to the threshold level below which may be effective as causing an increase in stimulation amplitude to reduce symptoms. In other examples, more or fewer LSB values may be used to calculate the average. The average high LSB may be shown in graph 1110 of FIG. 1 IB as threshold range 1114 indicating that the selected upper threshold value should be set at or below the threshold range 1114.

[0150] Table 2 below indicates side effect patient events for the left side of the body which correspond to sensed brain signals in the right hemisphere. The left column indicates the specific patient event, and the right column indicates the computed LSB value from the LFP snapshot associated with the patient event.Table 2.

[0151] As shown above in Table 2, the highest three LSB values average to an LSB value of 471. This LSB value corresponds to the threshold level above which may be effective as causing a decrease in stimulation amplitude to reduce side effects (e.g., dyskinesia). In other examples, more or fewer LSB values may be used to calculate the average. The average low LSB may be shown in graph 1110 of FIG. 1 IB as threshold range 1112 indicating that the selected lower threshold value should be set at or above the threshold range 1112. This similar process may be used for any type of adaptive stimulation.Docket No.: A0011558W001

[0152] In some examples, the user may manually determine the desired adjusted upper threshold and adjusted lower threshold to be within the respective threshold ranges 1114 and 1112 (e.g., each threshold being between 1114 and 1112). In other examples, processing circuitry 310 may automatically select adjusted threshold values according to a percentage of that LSB threshold range, the percentage of value between upper and lower threshold range 1114 and 1112, or to a predetermined magnitude above or below the limit of each threshold range 1114 and 1112. The system may do this for each hemisphere such that the one or more threshold values are specific to the sensed values for each hemisphere.

[0153] FIG. 12 is a flowchart illustrating an example technique for determining and displaying a range of values for one or more thresholds defining aDBS therapy. The example of FIG. 12 (and other techniques regarding guided programming herein) will be described with respect to programmer 104 and processing circuitry 310. However, some or all of these techniques may alternatively be performed by other devices or systems, such as IMD 106 or another external device. In some examples, multiple devices may perform these techniques in a distributed fashion toward completion.

[0154] As shown in the example of FIG. 12, processing circuitry 310 of system 100 may receive event information representing sensed bioelectric brain signals (e.g., LFP signals) corresponding to one or more patient events during aDBS therapy (1200). These patient events may include symptom occurrences and / or side effect occurrences. In some examples, the technique of FIG. 12 may include sensing signals or other events that do not occur during delivery of therapy. Processing circuitry 310 may then determine, based on the event information and threshold determination instructions, a range of values for at least one threshold defining aDBS therapy (1202). The range of values may be determined by two constraining values, or a minimum or maximum value where the valid threshold value may be at or above the minimum or at or below the maximum. In some examples, processing circuitry 310 may calculate LSB values that normalize the LFP power over a period of time that enables the system to compare LFP signals sensed over different time periods.

[0155] Processing circuitry 310 can then control a display device (e.g., of programmer 104) to present an indication of the range of values of the at least one threshold (1204). Such ranges may correspond to threshold ranges 1112 and 1114 of FIG. 1 IB. Processing circuitry 310 can then receive user input via a user interface, where the user input select a value from the range of values for the at least one threshold (1206). Then, processing circuitry 310 can control IMD 106 to deliver subsequent aDBS therapy according to the value for the at least one threshold (1208). Processing circuitry 310 may repeat this process periodically or inDocket No.: A0011558W001 response to user input or detect patient events during patient therapy to update the thresholds and / or other parameters as needed to improve therapy efficacy.

[0156] In some examples, processing circuitry 310 may be configured to change an upper and / or lower threshold in response to detected event information indicative of a threshold that needs to change. Processing circuitry 310 may utilize a predetermined percentage reduction or increase in the LFP or LSB value (e.g., 10%, 20%, 30%, etc.) in order to quickly adjust threshold. For example, if the LFP power value for an upper threshold was 900 when an event was detected, processing circuitry 310 may reduce the upper threshold by 20% to 720. The new threshold of 720 may be better set to adjust aDBS and avoid the same event in the future. If the event is detected again, processing circuitry 310 can apply the predetermined percentage reduction again. Processing circuitry 310 may present a confirmation, or recommendation, to the user for approval or selection in other examples. In some examples, processing circuitry 310 may use a fine tuning approach for automatically adjusting thresholds. If the threshold is still not appropriate after the first adjustment, processing circuitry 310 may use a smaller percentage to make smaller iterative adjustments to the thresholds until no further events are detected. These smaller adjustments may be done for increasing and / or decreasing the threshold value. In some examples, the smaller adjustments may be iteratively reduced by a certain percent value or to predetermined increments, such as going from 20%, to 5%, to 2%, to a smallest increment change of 1%.

[0157] FIG. 13 is a flowchart illustrating an example technique for selecting a value for one or more thresholds defining aDBS therapy based on event information. The example of FIG. 13 (and other techniques regarding guided programming herein) will be described with respect to programmer 104 and processing circuitry 310. However, some or all of these techniques may alternatively be performed by other devices or systems, such as IMD 106 or another external device. In some examples, multiple devices may perform these techniques in a distributed fashion toward completion.

[0158] As shown in the example of FIG. 13, processing circuitry 310 of system 100 may receive event information representing sensed bioelectric brain signals (e.g., LFP signals) corresponding to one or more patient events during aDBS therapy (1300). These patient events may include symptom occurrences and / or side effect occurrences. In some examples, the technique of FIG. 13 may include sensing signals or other events that do not occur during delivery of therapy. Processing circuitry 310 may then determine, based on the event information and threshold determination instructions, a range of values for at least one threshold defining aDBS therapy (1302). The range of values may be determined by twoDocket No.: A0011558W001 constraining values, or a minimum or maximum value where the valid threshold value may be at or above the minimum or at or below the maximum. In some examples, processing circuitry 310 may calculate LSB values that normalize the LFP power over a period of time that enables the system to compare LFP signals sensed over different time periods.

[0159] Processing circuitry 310 can then automatically select a value from the range of values for the at least one threshold (1304). In some examples, processing circuitry 310 may directly install this change to the threshold values. In other examples, processing circuitry 310 may present the selected value for the threshold to the user (e.g., clinician or patient) for confirmation before updating therapy. In other examples, processing circuitry 310 may directly select the adjusted value for the one or more thresholds without first determining the range of values. Processing circuitry 310 can control IMD 106 to deliver subsequent aDBS therapy according to the value for the at least one threshold (1306). Processing circuitry 310 may repeat this process periodically or in response to user input or detect patient events during patient therapy to update the thresholds and / or other parameters as needed to improve therapy efficacy.

[0160] FIG. 14 is a block diagram illustrating an example system 1400 that includes an external device, such as a server 1482, and one or more computing devices 1484A-1484N, that are coupled to IMD 106 and external programmer 104 shown in FIGS. 1 A-1B via a network 1486. In this example, IMD 106 may use its telemetry circuit 88 to communicate with external programmer 104 via a first wireless connection, and to communicate with an access point 1488 via a second wireless connection. In some examples, system 1400 may include additional devices. For example, system 1400 may also include communication device 1402 which may be an intermediary device that is configured to communicate with IMD 106 via one communication protocol and communicate with programmer 104 and / or network 1486 with a different communication protocol. Communication device 1402 may provide other functionality, such as recharging functionality for a rechargeable battery of IMD 106. Communication device 1402 may be referred to as an “intermediate device” that can act to transfer data between IMD 106 and network 1486 and other servers or computing devices.

[0161] System 1400 may be a part of a digital health platform that can share information between devices and enable certain functionality, such as sharing information sensed or otherwise obtained by IMD 106 and / or programmer 104 to other remote computing devices in addition to transferring updated sensing and / or programming instructions from remoteDocket No.: A0011558W001 computing devices such as server 1482 and / or computing devices 1484A-1484N back to programmer 104 and / or IMD 106.

[0162] In the example of FIG. 14, access point 1488, external programmer 104, server 1482, and computing devices 1484A-1484N are interconnected, and able to communicate with each other, through network 1486. In some cases, one or more of access point 1488, external programmer 104, server 1482, and computing devices 1484A-1484N may be coupled to network 1486 through one or more wireless connections. IMD 106, external programmer 104, server 1482, and computing devices 1484A-1484N may each comprise one or more processors, such as one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), programmable logic circuitry, or the like, that may perform various functions and operations, such as those described in this disclosure.

[0163] Access point 1488 may comprise a device, such as a home monitoring device, that connects to network 1486 via any of a variety of connections, such as telephone dial-up, digital subscriber line (DSL), cable modem connections, fiber optic communications, etc. In other examples, access point 1488 may be coupled to network 1486 through different forms of connections, including wired or wireless connections.

[0164] During operation, IMD 106 may collect and store various forms of data. For example, IMD 106 may collect sensed electrical signals and / or event data during therapy delivery that indicate therapy efficacy and / or disease state of patient 12. In some cases, IMD 106 may directly analyze the collected data to evaluate the patient 12, such as identifying events and / or sensed data. In other cases, however, IMD 106 may send stored data relating to events and / or other sensed data to external programmer 104 and / or server 1482, either wirelessly or via access point 1488 and network 1486, for remote processing and analysis. For example, IMD 106 may transmit sensed information, such as event data, to computing device 1484 A, and computing device 1484 A can evaluate the sensed information and generated updated stimulation parameters, event data, or other information pertaining to the patient.

[0165] In some cases, server 1482 may be configured to provide a secure storage site for archival of information that has been collected from IMD 106, external programmer 104, or any other devices of system 1400. Network 1486 may comprise a local area network, wide area network, or global network, such as the Internet. In some cases, external programmer 104 or server 1482 may assemble sensed data, event data, or other therapy information in web pages or other documents for viewing by trained professionals, such as clinicians, viaDocket No.: A0011558W001 viewing terminals associated with computing devices 1484A-1484N. In this manner, system 1400 functioning as a digital health platform may enable cloud-based functionality for any of the processes and / or user interactions described herein.

[0166] For example, a user may be able to log into the digital health platform of system 1400 via one or more devices such as any of computing devices 1484A-1484N. In one example, a user may log into the digital health platform using computing device 1484 A. The user may interact with a user interface that is displayed via an internet browser or specific application. For example, screens of user interface 400 may be displayed. With respect to the functionality described herein, the platform may provide the user with information related to event data and / or therapy, such as which hemisphere of the brain is associated with a symptom or side effect that has occurred or is occurring, and the LSB value of sensed bioelectric signal information associated with that symptom, side effect, or related event. In some examples, the user interface provided via the digital health platform may include information such as graphs 1100 and 1110 of FIGS. 11 A and 1 IB. The user interface may then be configured to receive user input approving a suggested updated threshold(s) according to the LSB value or adjusting the threshold(s). In some examples, the user interface may present additional information regarding the one or more thresholds. For example, the user interface may present information that setting a threshold within the range suggested by the LSB value(s) may reduce an occurrence of an event because adaptive stimulation therapy will be adjusted based on the updated threshold(s). System 1400 may then transmit the updated threshold(s) back to IMD 106 via network 1486.

[0167] Furthermore, although the disclosure is described with respect to DBS therapy, such techniques may be applicable to IMDs that convey other therapies in which sensed data and event data information is important, such as, e.g., spinal cord stimulation (SCS), pelvic floor stimulation, gastric stimulation, occipital stimulation, functional electrical stimulation, and the like. Also, in some aspects, techniques for evaluating posture state information, as described in this disclosure, may be applied to IMDs that provide other therapy (e.g., drug pumps) or IMDs that are generally dedicated to sensing or monitoring and do not include stimulation or other therapy components.

[0168] The following examples are described herein.

[0169] Example 1. A system comprising: processing circuitry configured to: receive sensed data indicative of bioelectric brain signals sensed during delivery of brain stimulation therapy to a patient; receive event data indicative of an event experienced by a patient during delivery of the brain stimulation therapy; identify a subset of the sensed data based on theDocket No.: A0011558W001 event data; determine, based on the subset of the sensed data and the event data, a range of values for at least one threshold defining subsequent brain stimulation therapy, the range of values determined to reduce an occurrence of the event during delivery of the subsequent brain stimulation therapy; and control a medical device to deliver the subsequent brain stimulation therapy according to the at least one threshold within the range of values.

[0170] Example 2. The system of example 1, wherein the event comprises at least one of a symptom occurrence or a side effect occurrence.

[0171] Example 3. The system of any of examples 1 or 2, wherein the sensed bioelectric brain signals include a local field potential (LFP) signal, and wherein the information representing the sensed brain signals comprises a characteristic value indicative of a power of the LFP signal.

[0172] Example 4. The system of any of example 3, wherein the processing circuitry is configured to calculate the characteristic value by at least: determining a spectral power value of the LFP signal for each time period of a plurality of time periods; and summing the spectral power from each time period of the plurality of time periods to calculate an accumulated power corresponding to the event.

[0173] Example 5. The system of any of examples 1 through 4, wherein the processing circuitry is configured to: determine, according to the event data and the sensed data, a value within the range of values for the at least one threshold; and control the medical device to deliver the subsequent brain stimulation therapy according to the value.

[0174] Example 6. The system of any of examples 1 through 5, wherein the processing circuitry is configured to: control a display device to present the range of values via a user interface; receive, via the user interface, user input selecting a value within the range for the at least one threshold; and control the medical device to deliver the subsequent brain stimulation therapy according to the value of the at least one threshold.

[0175] Example 7. The system of any of examples 1 through 6, wherein the at least one threshold comprises an upper threshold and a lower threshold that define the brain stimulation therapy and the subsequent brain stimulation therapy.

[0176] Example 8. The system of any of examples 1 through 7, wherein the event data comprises value data for a stimulation parameter corresponding to the sensed bioelectric brain signals, and wherein the processing circuitry is configured to determine, based on the event data, one or more limits for the stimulation parameter that at least partially defines the subsequent brain stimulation therapy.Docket No.: A0011558W001

[0177] Example 9. The system of any of examples 1 through 8, further comprising an external programmer comprising the processing circuitry.

[0178] Example 10. The system of any of examples 1 through 9, further comprising the medical device, wherein the medical device is configured to be implanted within the patient.

[0179] Example 11. A method comprising: receiving, by processing circuitry, sensed data indicative of bioelectric brain signals sensed during delivery of brain stimulation therapy to a patient; receiving, by the processing circuitry, event data indicative of an event experienced by a patient during delivery of the brain stimulation therapy; identifying, by the processing circuitry, a subset of the sensed data based on the event data; determining, by the processing circuitry and based on the subset of the sensed data and the event data, a range of values for at least one threshold defining subsequent brain stimulation therapy, the range of values determined to reduce an occurrence of the event during delivery of the subsequent brain stimulation therapy; and controlling, by the processing circuitry, a medical device to deliver the subsequent brain stimulation therapy according to the at least one threshold within the range of values.

[0180] Example 12. The method of example 11, wherein the event comprises at least one of a symptom occurrence or a side effect occurrence.

[0181] Example 13. The method of any of examples 11 or 12, wherein the sensed bioelectric brain signals include a local field potential (LFP) signal, and wherein the information representing the sensed brain signals comprises a characteristic value indicative of a power of the LFP signal.

[0182] Example 14. The method of any of example 13, wherein calculating the characteristic value comprises: determining a spectral power value of the LFP signal for each time period of a plurality of time periods; and summing the spectral power from each time period of the plurality of time periods to calculate an accumulated power corresponding to the event.

[0183] Example 15. The method of any of examples 11 through 14, further comprising: determining, according to the event data and the sensed data, a value within the range of values for the at least one threshold; and controlling the medical device to deliver the subsequent brain stimulation therapy according to the value.

[0184] Example 16. The method of any of examples 11 through 15, further comprising: controlling a display device to present the range of values via a user interface; receiving, via the user interface, user input selecting a value within the range for the at least one threshold;Docket No.: A0011558W001 and controlling the medical device to deliver the subsequent brain stimulation therapy according to the value of the at least one threshold.

[0185] Example 17. The method of any of examples 11 through 16, wherein the at least one threshold comprises an upper threshold and a lower threshold that define the brain stimulation therapy and the subsequent brain stimulation therapy.

[0186] Example 18. The system of any of examples 11 through 17, wherein the event data comprises value data for a stimulation parameter corresponding to the sensed bioelectric brain signals, and wherein the method further comprises determining, based on the event data, one or more limits for the stimulation parameter that at least partially defines the subsequent brain stimulation therapy.

[0187] Example 19. The method of any of examples 11 through 18, wherein an external programmer comprises the processing circuitry.

[0188] Example 20. A non-transitory computer-readable medium comprising instructions that, when executed, control processing circuitry to: receive sensed data indicative of bioelectric brain signals sensed during delivery of brain stimulation therapy to a patient; receive event data indicative of an event experienced by a patient during delivery of the brain stimulation therapy; identify a subset of the sensed data based on the event data; determine, based on the subset of the sensed data and the event data, a range of values for at least one threshold defining subsequent brain stimulation therapy, the range of values determined to reduce an occurrence of the event during delivery of the subsequent brain stimulation therapy; and control a medical device to deliver the subsequent brain stimulation therapy according to the at least one threshold within the range of values.

[0189] The techniques described in this disclosure, including those attributed to IMD 106, programmer 104, or various constituent components, may be implemented, at least in part, in hardware, software, firmware or any combination thereof. For example, various aspects of the techniques may be implemented within one or more processors, including one or more microprocessors, DSPs, ASICs, FPGAs, or any other equivalent integrated or discrete logic circuitry, as well as any combinations of such components, embodied in programmers, such as clinician or patient programmers, medical devices, or other devices.

[0190] In one or more examples, the functions described in this disclosure may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored, as one or more instructions or code, on a computer- readable medium and executed by a hardware-based processing unit. Computer-readable media may include computer-readable storage media forming a tangible, non-transitoryDocket No.: A0011558W001 medium. Instructions may be executed by one or more processors, such as one or more DSPs, ASICs, FPGAs, general purpose microprocessors, or other equivalent integrated or discrete logic circuitry. Accordingly, the term “processor,” as used herein may refer to one or more of any of the foregoing structures or any other structure suitable for implementation of the techniques described herein.

[0191] In addition, in some respects, the functionality described herein may be provided within dedicated hardware and / or software modules. Depiction of different features as modules or units is intended to highlight different functional aspects and does not necessarily imply that such modules or units must be realized by separate hardware or software components. Rather, functionality associated with one or more modules or units may be performed by separate hardware or software components or integrated within common or separate hardware or software components. Also, the techniques may be fully implemented in one or more circuits or logic elements. The techniques of this disclosure may be implemented in a wide variety of devices or apparatuses, including an IMD, an external programmer, a combination of an IMD and external programmer, an integrated circuit (IC) or a set of ICs, and / or discrete electrical circuitry, residing in an IMD and / or external programmer.

[0192] Various examples have been described. These and other examples are within the scope of the following claims.

Claims

Docket No.: A0011558W001WHAT IS CLAIMED IS:

1. A system comprising: processing circuitry configured to: receive sensed data indicative of bioelectric brain signals sensed during delivery of brain stimulation therapy to a patient; receive event data indicative of an event experienced by a patient during delivery of the brain stimulation therapy; identify a subset of the sensed data based on the event data; determine, based on the subset of the sensed data and the event data, a range of values for at least one threshold defining subsequent brain stimulation therapy, the range of values determined to reduce an occurrence of the event during delivery of the subsequent brain stimulation therapy; and control a medical device to deliver the subsequent brain stimulation therapy according to the at least one threshold within the range of values.

2. The system of claim 1, wherein the event comprises at least one of a symptom occurrence or a side effect occurrence.

3. The system of any of claims 1 or 2, wherein the sensed bioelectric brain signals include a local field potential (LFP) signal, and wherein the information representing the sensed brain signals comprises a characteristic value indicative of a power of the LFP signal.

4. The system of any of claim 3, wherein the processing circuitry is configured to calculate the characteristic value by at least: determining a spectral power value of the LFP signal for each time period of a plurality of time periods; and summing the spectral power from each time period of the plurality of time periods to calculate an accumulated power corresponding to the event.

5. The system of any of claims 1 through 4, wherein the processing circuitry is configured to: determine, according to the event data and the sensed data, a value within the range of values for the at least one threshold; andDocket No.: A0011558W001 control the medical device to deliver the subsequent brain stimulation therapy according to the value.

6. The system of any of claims 1 through 5, wherein the processing circuitry is configured to: control a display device to present the range of values via a user interface; receive, via the user interface, user input selecting a value within the range for the at least one threshold; and control the medical device to deliver the subsequent brain stimulation therapy according to the value of the at least one threshold.

7. The system of any of claims 1 through 6, wherein the at least one threshold comprises an upper threshold and a lower threshold that define the brain stimulation therapy and the subsequent brain stimulation therapy.

8. The system of any of claims 1 through 7, wherein the event data comprises value data for a stimulation parameter corresponding to the sensed bioelectric brain signals, and wherein the processing circuitry is configured to determine, based on the event data, one or more limits for the stimulation parameter that at least partially defines the subsequent brain stimulation therapy.

9. The system of any of claims 1 through 8, further comprising an external programmer comprising the processing circuitry.

10. The system of any of claims 1 through 9, further comprising the medical device, wherein the medical device is configured to be implanted within the patient.

11. The system of any of claims 1 through 10, further comprising sensing circuitry configured to sense the bioelectric brain signals.

12. The system of any of claims 1 through 11, further comprising stimulation circuitry configured to deliver the brain stimulation therapy and the subsequent brain stimulation therapy.Docket No.: A0011558W00113. A non-transitory computer-readable medium comprising instructions that, when executed, control the processing circuitry to perform functions of any of claims 1 through 12.

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