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EP-4739198-A1 - SYSTEMS AND METHODS FOR DETECTING SIGNAL EXTREMUM

EP4739198A1EP 4739198 A1EP4739198 A1EP 4739198A1EP-4739198-A1

Abstract

A system may include data acquisition circuitry, local extremum detection circuitry, difference monitoring circuitry, comparator circuitry and extremum data recorder circuitty. The data acquisition circuitry may be configured to access a series of data, samples from a sensor signal. The local extremum detection circuitry may be configured to find a local extremum in the series of data samples. The difference monitoring circuitry may be configured to determine a difference between the local extremum and the series of data samples subsequent to and receding from the local extremum toward the first- direction. The comparator circuitry may be configured to compare the difference to a predefined threshold. The extremum data recorder circuitry may be configured to write extremum data into storage when the difference exceeds the predefined threshold.

Inventors

  • WEISS, PHILIP LEONARD

Assignees

  • Boston Scientific Neuromodulation Corporation

Dates

Publication Date
20260513
Application Date
20240709

Claims (15)

  1. What is claimed is: 1. A system, comprising: data acquisition circuitry configured to access a series of data samples from a sensor signal; local extremum detection circuitry configured to find a local extremum in the series of data samples, wherein at least one data sample immediately preceding the local extremum approaches the local extremum from a first direction and at least one data sample immediately succeeding the local extremum recedes from the local extremum toward the first direction; difference monitoring circuitry configured to determine a difference between the local extremum and the series of data samples subsequent to and receding from the local extremum toward the first direction; comparator circuitry configured to compare the difference to a predefined threshold; and extremum data recorder circuitry configured to write extremum data into storage when the difference exceeds the predefined threshold.
  2. 2. The system according to claim 1, further comprising a sensor configured to sense a biological parameter from a patient and provide the sensor signal, and a sensor signal sampler configured to sample the sensor signal to provide the series of data samples.
  3. 3. The system according to claim 2, wherein the data acquisition circuitry is configured to access a stream of data samples.
  4. 4. The system according to any of claims 2-3, further comprising a stimulator configured to deliver electrical stimulation, where the data acquisition circuitry is configured to use the sensor to sense a response to the electrical stimulation.
  5. 5. The system according to claim 4, wherein the data acquisition circuitry is configured to access sample data within a window after a stimulation pulse and timed to avoid a stimulation artifact and to capture an evoked potential from the delivered electrical stimulation
  6. 6. The system according to any of claims 2-5, wherein the sensor includes an evoked compound action potential (ECAP) sensor, a local field potential (LFP) sensor, an evoked resonant neural activity (ERNA) sensor, or a cardiac activity sensor.
  7. 7. The system according to any of claims 1-6, wherein the local extremum detection circuitry is configured to find the local extremum by determining a potential extremum using a datapoint in the series of sample data, and updating the potential extremum when the difference did not reach the predefined threshold and a subsequent datapoint in the series of sample data is more extreme.
  8. 8. The system according to any of claims 1-7, wherein when the local extremum is a local maxima, the predefined threshold is a predefined local maxima threshold, the series of sample data points immediately subsequent to the local maxima is less than the local maxima, and local maxima data is written into the storage when the series of sample data points is less than the local maximal by at least the predefined local maxima threshold.
  9. 9. The system according to any of claims 1-8, wherein when the local extremum is a local minima, the predefined threshold is a predefined local minima threshold, the series of sample data points immediately subsequent to the local minima is greater than the local minima, and local minima data is written into the storage when the series of sample data points is more than the local minima by at the predefined local minima threshold.
  10. 10. The system according to any of claims 1-9, wherein the storage includes First In First Out (FIFO) storage, and the extremum data recorder circuitry is configured to write extremum data into storage by writing extremum data into the FIFO and then from the FIFO into a persistent memory.
  11. 11. The system according to any of claims 1-10, wherein the local extremum detection circuitry is further configured to perform recursive averaging to reduce noise in finding the local extremum.
  12. 12. The system according to any of claims 1-11, further comprising a medical device programmer with a user-interface configured to receive the predefined threshold.
  13. 13. The system according to any of claims 1-12, wherein the extremum data written into the storage includes at least one of: a value for the extremum data; or a length or an amplitude of a chord between successive local extremums.
  14. 14. The system according to any of claims 1-13, wherein the comparator circuitry is further configured to compare the local extremum to an expected extremum to provide a confidence indicator for the extremum date written into the storage.
  15. 15. The system according to any of claims 1-14, wherein the local extremum detection circuitry, the difference monitoring circuitry, the comparator circuitry and the extremum data recorder circuitry are configured to operate on each of a plurality of local extremums in the series of sample data points.

Description

SYSTEMS AND METHODS FOR DETECTING SIGNAL EXTREMUM TECHNICAL FIELD [0001] This application claims the benefit of U.S. Provisional Application No. 63/526,950 filed on July 14, 2023, which is hereby incorporated by reference in its entirety. TECHNICAL FIELD [0002] This document relates generally to medical systems, and more particularly, but not by way of limitation, to systems, devices, and methods for detecting extrema in signals such as local maxima and/or minima in sensed physiological signals. BACKGROUND [0003] Signals may be analyzed to evaluate and characterize systems. Signal features such as local extrema (e.g., minima and maxima) may be used to derive information about the system. By way of example and not limitation, physiological signals may be used to evaluate a patient. A patient state, for example, may be sensed by detecting one or more sensed signals. The determined patient state may be used to trigger an initiation of a therapy, a suspension of a therapy, or a change in the therapy. The detected signal may closely correspond to the intended effect of therapy such that information from the detected window may be used to provide closed-loop control of the stimulation or to evaluate an efficacy of different stimulation programs. By way of example and not limitation, neurostimulation has been proposed as a therapy for a number of conditions. Often, neurostimulation and neuromodulation may be used interchangeably to describe excitatory stimulation that causes action potentials as well as inhibitory and other effects. Examples of neuromodulation include Spinal Cord Stimulation (SCS), Deep Brain Stimulation (DBS), Peripheral Nerve Stimulation (PNS), and Functional Electrical Stimulation (FES). Neurostimulation systems may deliver the therapy based on sensed physiological signals. [0004] Sensed physiological signals, such as but not limited to, may have a complex morphology. Furthermore, noise may add to the complexity of the signal. Some examples of physiological signals with complex morphologies include local field potentials and evoked compound action potentials (ECAPs) and evoked resonant neural activity (ERNA). Other examples of sensed physiological signals may include cardiac activity (e.g., electrocardiography (ECG)), muscle activity (e.g., electromyography (EMG)), brain activity (e.g., electroencephalography (EEG)), electroneuronography (ENOG)) and galvanic skin responses (GSR). Other examples of sensed physiological signals include impedance (e.g., respiration sensors / transthoracic impedance) or movement (e.g., movement detected using an accelerometer or camera). The movement may be for the whole person or for a portion of the patient such limb movement, head movement, or eye movement. [0005] Extrema in the signals, including peaks (e.g., also referred to as local maximums) and troughs (also referred to as a local minimums), can contain useful information. However, there are challenges associated with accurately detecting extrema in signals. For example, the detected extrema should correspond to a number of extrema expected to be found within a size of a sampling window. Also, noise may be present in the signals. Thus, some fluctuations in the signal should be ignored and should not be classified as a local extremum. SUMMARY [0006] By way of example and not limitation, various embodiments provided herein use at least one threshold for ignoring some signal fluctuations and classifying other signal fluctuations as local extrema. [0007] An example (e.g., Example 1) of a system may include data acquisition circuitry, local extremum detection circuitry, difference monitoring circuitry, comparator circuitry and extremum data recorder circuitry. The data acquisition circuitry may be configured to access a series of data samples from a sensor signal. The local extremum detection circuitry may be configured to find a local extremum in the series of data samples. The local extremum is a data sample where at least one data sample immediately preceding the local extremum approaches from a first direction and at least one data sample immediately succeeding the local extremum recedes toward the first direction. The difference monitoring circuitry may be configured to determine a difference between the local extremum and the series of data samples subsequent to and receding from the local extremum toward the first direction. The comparator circuitry may be configured to compare the difference to a predefined threshold. The extremum data recorder circuitry may be configured to write extremum data into storage when the difference exceeds the predefined threshold. [0008] In Example 2, the subject matter of Example 1 may optionally be configured to further include a sensor configured to sense a biological parameter from a patient and provide the sensor signal, and a sensor signal sampler configured to sample the sensor signal to provide the series of data samples. [0009] In Example 3, the subject matter o