Dynamic ECAP Sensing Window for Neural Stimulation Latency

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Solution Overview

Problem

Current medical devices face challenges in accurately detecting evoked compound action potential (ECAP) signals due to changes in latency, which can lead to ineffective adjustment of electrical stimulation therapy, especially with patient movement affecting electrode position relative to target nerves.

Innovation Solution

A system that determines a sensing window based on stimulation parameter values to detect ECAP signal features, adjusting the window duration or start time to accommodate patient-specific conditions and changes in neural recruitment, allowing for closed-loop control of electrical stimulation therapy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a fixed sensing window is used to detect ECAP signals, then the device complexity is reduced, but the measurement precision deteriorates due to latency changes in ECAP signals

Engineering Contradiction:

Improvesensing window configurationVSAvoidECAP signal detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The sensing window is made dynamic by adjusting its start time and duration based on the stimulation pulse parameters. The system calculates the expected ECAP latency based on the stimulation pulse characteristics and dynamically positions the sensing window to capture the ECAP signal features accurately, resolving the contradiction between fixed simplicity and adaptive precision.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the sensing window parameters (start time, duration) based on stimulation pulse parameters. By establishing a relationship between stimulation parameters and ECAP latency, the system adjusts the sensing window parameters to maintain optimal detection accuracy across different stimulation conditions.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If the sensing window is adjusted based on stimulation parameters, then the measurement precision of ECAP detection is improved, but the device complexity increases

Engineering Contradiction:

ImproveECAP signal feature detectionVSAvoidsensing window adjustment mechanism

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary calculation of the expected ECAP latency based on stimulation pulse parameters before the actual ECAP detection. By pre-determining the optimal sensing window parameters based on the stimulation characteristics, the system avoids complex real-time adjustments during ECAP detection, reducing the effective complexity while maintaining precision.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system replaces complex mechanical or hardware adjustment mechanisms with computational methods. By using algorithms to calculate and adjust sensing window parameters based on stimulation parameters and expected latency relationships, the system achieves precise ECAP detection through software-based control rather than complex hardware adjustments.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If a standard sensing window duration is used, then the ease of operation is improved, but the reliability of therapy adjustment deteriorates due to patient-specific latency variations

Engineering Contradiction:

Improvesensing window configurationVSAvoidtherapy adjustment accuracy

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system applies local quality by tailoring the sensing window parameters to each patient's specific neural response characteristics. By determining patient-specific latency relationships between stimulation parameters and ECAP signals, the system customizes the sensing window for each patient, ensuring reliable therapy adjustment while maintaining ease of operation through automated parameter determination.

Inventive Principle:

Principle #3Local quality

4Device complexity

If the sensing window start time is fixed, then the device complexity is reduced, but the loss of information increases due to latency shifts in ECAP features

Engineering Contradiction:

Improvesensing window timing controlVSAvoidECAP signal features

Core Design Contradiction:

Device complexityVSLoss of information

Solution Approach 1:

The sensing window start time is made dynamic by basing it on the expected ECAP latency derived from stimulation pulse parameters. The system calculates the optimal start time to capture ECAP features despite latency variations, preventing information loss while avoiding complex fixed-time adjustments through parameter-based dynamic positioning.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS20220401737A1Latency compensation for detection of ecaps

Publication Date: 2022.12.22 MEDTRONIC INC

AI summary

Systems, devices, and techniques are described for adjusting a sensing window for sensing a feature of an evoked compound action potential (ECAP). In one example, a medical device includes processing circuitry configured to determine a value of a stimulation parameter that at least partially defines an electrical stimulation pulse and select, based on the value of the stimulation parameter, a sensing window for detecting one or more features of a sensed evoked compound action potential (ECAP) signal elicited by the electrical stimulation pulse. The processing circuitry can also determine a value of each of the one or more features within the sensing window from the sensed ECAP signal and control, based on the value of each of the one or more features, subsequent electrical stimulation deliverable to a patient.