ECAP-Detected Sub-Threshold Stimulation for Consistent Therapy

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Solution Overview

Problem

Existing medical devices struggle to maintain consistent delivery of electrical stimulation therapy as the distance between electrodes and target tissue changes due to patient movement or lead migration, leading to unpredictable perception and detection of stimulation by the patient or device.

Innovation Solution

A medical device that senses evoked compound action potentials (ECAPs) to adjust stimulation parameters, allowing for sub-threshold electrical stimulation therapy delivery, which is not perceived by the patient and maintains therapeutic efficacy while reducing side effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrical stimulation therapy is delivered at higher intensity to ensure therapeutic efficacy, then pain relief effectiveness is improved, but patient perception of uncomfortable sensations and side effects increases

Engineering Contradiction:

Improvetherapeutic efficacyVSAvoiduncomfortable sensations

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system continuously monitors ECAP signals in real-time and uses this feedback to dynamically adjust stimulation parameters. The processing circuitry compares detected ECAP amplitudes against threshold values and automatically modifies pulse amplitude, pulse width, or frequency to maintain therapeutic effect while preventing uncomfortable sensations, thereby resolving the contradiction between efficacy and patient comfort

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically changes stimulation parameters (amplitude, pulse width, frequency) based on detected ECAP characteristics. By adjusting these parameters in response to ECAP feedback, the system maintains therapeutic efficacy through optimized neural activation while keeping stimulation intensity below perception thresholds, thus eliminating uncomfortable sensations

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If fixed stimulation parameters are used to simplify device operation, then ease of operation is improved, but consistency of therapy delivery deteriorates due to patient movement or lead migration

Engineering Contradiction:

Improvedevice operation simplicityVSAvoidtherapy delivery consistency

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system performs self-adjustment by automatically detecting ECAP signals and modifying stimulation parameters without requiring external intervention. The processing circuitry continuously monitors therapy response and autonomously optimizes delivery parameters, enabling the device to maintain consistent therapeutic effect despite patient movement or lead migration while keeping the operation simple for the user

Inventive Principle:

Principle #25Self-service

3Measurement precision

If ECAP monitoring is continuously performed to maintain optimal therapy, then therapy precision is improved, but energy consumption increases

Engineering Contradiction:

Improvetherapy precisionVSAvoidenergy consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system performs ECAP monitoring and parameter adjustment at periodic intervals rather than continuously. The processing circuitry evaluates ECAP signals at predetermined time points during therapy delivery and makes parameter adjustments based on these periodic assessments, thereby maintaining adequate therapy precision while significantly reducing energy consumption compared to continuous monitoring

Inventive Principle:

Principle #19Periodic action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system ensures consistent sub-perception therapy by periodically determining stimulation thresholds, adjusting parameters to maintain effective pain relief without patient awareness or detectable ECAP signals, thus enhancing therapy efficacy and comfort.

Implementation Method 1

An evoked compound action potential (ECAP) is synchronous firing of a population of neurons which occurs in response to the application of a stimulus including, in some cases, an electrical stimulus by a medical device

Methodology Applied

Scientific EffectEvoked compound action potential:

Data Source

PatentUS12357830B2Sub-threshold stimulation based on ECAP detection

Publication Date: 2025.07.15 MEDTRONIC INC

AI summary

Systems, devices, and techniques are described for determining stimulation parameters based on one or more stimulation thresholds (e.g., a perception threshold or a detection threshold). In one example, a medical device includes sensing circuitry configured to sense one or more ECAP signals, wherein the sensing circuitry is configured to sense each ECAP signal of the one or more ECAPs elicited by a respective control pulse of a plurality of control pulses, and the medical device includes processing circuitry configured to determine, based on the one or more ECAP signals, a stimulation level for the plurality of control pulses that achieves a stimulation threshold, determine, based on the stimulation level, a value of a stimulation parameter that at least partially defines a plurality of therapy pulses of electrical stimulation therapy, and control stimulation generation circuitry to deliver the electrical stimulation therapy according to the value of the stimulation parameter.