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EP-4221816-B1 - LEAD INTEGRITY AND CLOSED-LOOP ALGORITHM DIAGNOSTIC

EP4221816B1EP 4221816 B1EP4221816 B1EP 4221816B1EP-4221816-B1

Inventors

  • LI, Jiashu
  • BOURGET, DUANE L.
  • HAGEMAN, Kristin N.
  • BINK, Hank

Dates

Publication Date
20260506
Application Date
20210927

Claims (15)

  1. A method comprising: receiving, by processing circuitry (210), information indicative of one or more evoked compound action potential, ECAP, signals (404), the one or more ECAP signals sensed by at least one electrode (232, 234) carried by a medical lead (130A, 130B); determining, by processing circuitry, that at least one characteristic value of the one or more ECAP signals is outside of an expected range; characterised by responsive to determining that the at least one characteristic value of the one or more ECAP signals is outside of the expected range, performing, by the processing circuitry, a lead integrity test for the medical lead.
  2. The method of claim 1, further comprising: receiving, by the processing circuitry, accelerometer data indicative of patient movement; determining, by the processing circuitry and based on the accelerometer data, that a circadian rhythm of a patient is within a normal circadian rhythm range; determining, by the processing circuitry, the at least one characteristic value of the one or more ECAP signals is below the expected range; and responsive to determining that the circadian rhythm is within the normal circadian rhythm range and the characteristic value of the one or more ECAP signals is below the expected range, performing the lead integrity test.
  3. The method of claim 2, further comprising performing the lead integrity test that comprises measuring an impedance for the at least one electrode carried by the medical lead and determining whether the measured impedance is within one or more thresholds defined by stored instructions.
  4. The method of claim 1, further comprising: determining, by the processing circuitry, that the at least one characteristic value of the one or more ECAP signals is an amplitude above the expected range; comparing, by the processing circuitry, the at least one characteristic value of the one or more ECAP signals to at least one characteristic value of a baseline ECAP signal; and determining, by the processing circuitry, based on the comparison, that the at least one characteristic value of the one or more ECAP signals is outside of an expected range of the at least one characteristic value of the baseline ECAP signal.
  5. The method of claim 4, further comprising: responsive to a determination the at least one characteristic value is outside the expected range from the at least one characteristic value of the baseline ECAP signal, performing a lead integrity test that comprises measuring an impedance for the at least one electrode carried by the medical lead; determining, by the processing circuitry and based on lead integrity test results, that the measured impedance of the at least one electrode is within one or more thresholds defined by stored instructions; and outputting, by the processing circuitry based on a successful lead integrity test, a request for a user to adjust a closed-loop stimulation algorithm that controls delivery of electrical stimulation based on the ECAP signals.
  6. The method of claim 4, further comprising: responsive to determining that the at least one characteristic value of the one or more ECAP signals is outside the expected range of the at least one characteristic value of the baseline ECAP signal, performing the lead integrity test; determining, by the processor and based on the lead integrity test, that impedance measured at the at least one electrode of the medical lead is outside one or more thresholds defined by stored instructions; and responsive to the at least one electrode of the medical lead failing the lead integrity test, requesting, by the processing circuitry, a user to adjust a closed-loop stimulation algorithm that controls delivery of electrical stimulation based on the ECAP signals.
  7. The method of claim 4, further comprising: responsive to the comparison that the at least one characteristic value is outside the threshold of the at least one characteristic value of the baseline ECAP signal, determining, by the processing circuitry, the at least one characteristic value of the one or more ECAP signals comprises noise; performing the lead integrity test for the at least one electrode carried by the medical lead; determining, by the processing circuitry and based on the lead integrity test, the at least one electrode is within one or more thresholds defined by stored instructions; responsive to the lead integrity test, suspending, by the processing circuitry, closed-loop stimulation; periodically comparing, by the processing circuitry, the at least one characteristic value of the one or more ECAP signals against at least one characteristic value of the baseline ECAP signal; and responsive to the comparison of the at least one characteristic value of the one or more ECAP signals being within the expected range of the at least one characteristic value of the baseline ECAP signals, resuming, by the processing circuitry, the closed-loop stimulation.
  8. The method of claim 4, wherein the at least one electrode comprises a first recording electrode combination, and wherein the method further comprises: responsive to the comparison that the at least one characteristic value is outside the expected range from the at least one characteristic value of the baseline ECAP signal, determining, by the processing circuitry, the at least one characteristic value of the one or more ECAP signals comprises noise; performing the lead integrity test for the at least one electrode carried by the medical lead; responsive to lead integrity test, determining, by the processing circuitry, the lead integrity test of the first recording electrode combination is not within one or more thresholds defined by stored instructions; and responsive to the determination the first recording electrode combination is not within the one or more thresholds defined by the stored instructions, selecting, by the processing circuitry, a second recording electrode combination.
  9. The method of claim 1, further comprising: determining, by the processing circuitry, over a period of time the characteristic value of the one or more ECAP signals is a variance of the one or more ECAP signals; and responsive to the determination of the variance between the characteristic value and the one or more ECAP signals, periodically comparing, by the processing circuitry, the at least one characteristic value of the one or more ECAP signals against the at least one characteristic value of the baseline ECAP signal.
  10. The method of claim 9, further comprising: responsive to a comparison of the at least one characteristic value of the one or more ECAP signals being outside the expected range of the at least one characteristic value of the baseline ECAP signals, performing the lead integrity test for the at least one electrode carried by the medical lead; determining, by the processing circuitry, the lead integrity test is within limits defined by stored instructions; suspending, by the processing circuitry, closed-loop stimulation; periodically comparing, by the processing circuitry, the at least one characteristic value of the one or more ECAP signals against at least one characteristic value of the baseline ECAP signal; and resuming, by the processing circuitry and based upon the at least one characteristic value of the one or more ECAP signals within the expected range of the at least one characteristic value of the baseline ECAP signal, closed-loop stimulation.
  11. A medical device comprising: stimulation generation circuitry (202) configured to deliver a first stimulation pulse to a patient; sensing circuitry (206) configured to sense information indicative of one or more evoked compound action potential (ECAP) signals, where the sensing circuitry comprises at least one electrode carried by a medical lead; and processing circuitry configured to: receive information indicative of the one or more ECAP signals sensed by the at least one electrode carried by the medical lead; determine that at least one characteristic value of the one or more ECAP signals is outside of an expected range; characterised by said processing circuitry being further configured to responsive to determining that the at least one characteristic value of the one or more ECAP signals is outside of the expected range, perform a lead integrity test for the medical lead.
  12. The medical device of claim 11, wherein the processing circuitry is further configured to: receive accelerometer data indicative of patient movement; determine, based on the accelerometer data, that a circadian rhythm of a patient is within a normal circadian rhythm range; determine the at least one characteristic value of the one or more ECAP signals is below the expected range; and responsive to determining that the circadian rhythm is within the normal circadian rhythm range and the characteristic value of the one or more ECAP signals is below the expected range, performing the lead integrity test.
  13. The medical device of claim 12, wherein the lead integrity test comprises measuring an impedance for the at least one electrode carried by the medical lead and determining whether the measured impedance is within limits defined by stored instructions.
  14. The medical device of claim 11, wherein the medical device comprises an implantable medical device comprising the stimulation generation circuitry, the sensing circuitry, and the processing circuitry.
  15. A computer-readable storage medium comprising instructions that, when executed, cause processing circuitry to: receive information indicative of one or more evoked compound action potential (ECAP) signals, the one or more ECAP signals sensed by at least one electrode carried by a medical lead; determine that at least one characteristic value of the one or more ECAP signals is outside of an expected range; characterised by said computer-readable strorage medium comprising further instructions to perform, based on the determination that the at least one characteristic value of the one or more ECAP signals is outside of the expected range, a lead integrity test for the medical lead.

Description

TECHNICAL FIELD This disclosure generally relates to electrical stimulation therapy, and more specifically, control of electrical stimulation therapy. BACKGROUND Medical devices may be external or implanted and may be used to deliver electrical stimulation therapy to patients via various tissue sites to treat a variety of symptoms or conditions such as chronic pain, tremor, Parkinson's disease, epilepsy, urinary 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. Stimulation proximate the spinal cord, proximate the sacral nerve, within the brain, and proximate peripheral nerves are often referred to as spinal cord stimulation (SCS), sacral neuromodulation (SNM), deep brain stimulation (DBS), and peripheral nerve stimulation (PNS), respectively. US2015112408A1 relates to coding stimulation pulses for cochlear implant systems. SUMMARY The invention is defined in claims 1, 11 and 15. In general, the disclosure is directed to devices, systems, and techniques for controlling electrical stimulation therapy based on sensing artifacts of at least one of stimulation signals or evoked compound action potentials (ECAPs). A medical device (e.g., an implantable medical device) may deliver one or more stimulation signals (e.g., one or more pulses) to the patient via one or more leads, and the medical device may sense signals which may include respective ECAPs elicited by the pulses. The medical device may also sense ECAP signals elicited by a delivered pulse if the delivered pulse causes a sufficient number of nerve fibers to depolarize. Examples of the present disclosure generally relate to identifying issues that may occur during closed-loop stimulation, where the system employs ECAP signals in a closed-loop system to adjust one or more stimulation parameters that define subsequent stimulation pulses in electrical stimulation therapy. The issues may relate to medical lead integrity issues and/or noise interference (e.g., electromagnetic interference EMI) that may cause problems with properly detecting and/or recording ECAPs, which in turn affect the closed-loop stimulation ability to properly administer a patient's therapy. Therefore, the system may determine whether or not the detected signals are representative of expected ECAP signals and, if not expected, initiate a lead integrity test to identify the cause of the unexpected signals. In one example, the disclosure relates to a method comprising receiving, by processing circuitry, information indicative of one or more evoked compound action potential (ECAP) signals. The one or more ECAP signals are sensed by at least one electrode carried by a medical lead. The processing circuitry determining that at least one characteristic value of the one or more ECAP signals is outside of an expected range. Responsive to determining that the at least one characteristic value of the one or more ECAP signals is outside of the expected range, the processing circuitry performs a lead integrity test for the medical lead. In some examples, the disclosure relates to a medical device comprising stimulation generation circuitry configured to deliver a first stimulation pulse to a patient. Sensing circuitry of the medical device is configured to sense information indicative of one or more evoked compound action potential (ECAP) signals, where the sensing circuitry comprises at least one electrode carried by a medical lead. Processing circuitry of the medical device is configured to receive information indicative of the one or more ECAP signals sensed by the at least one electrode carried by the medical lead. The processing circuitry determines that at least one characteristic value of the one or more ECAP signals is outside of an expected range. Responsive to determining that the at least one characteristic value of the one or more ECAP signals is outside of the expected range, the processing circuitry performs a lead integrity test for the medical lead. In some examples, a computer-readable storage medium comprises instructions that, when executed, cause processing circuitry to receive information indicative of one or more evoked compound action potential (ECAP) signals. The one or more ECAP signals are sensed by at least one electrode carried by a medical lead. The processing circuitry determines that at least one characteristic value of the one or more ECAP signals is outside of an expected range. Based on the determination that the at least one characteristic value of the one or more ECAP signals is outside of the expected range, the processing circuitry performs a lead integrity test for the medical lead. The summary is intended to provide an overview of the subject matter described in this disclosure. I