Hybrid Neuromodulation Feedback Control for Stable ECAP Stimulation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing neuromodulation systems face challenges in maintaining optimal neural stimulation levels due to electrode migration and postural changes, leading to ineffective or painful stimulation.

Innovation Solution

A hybrid feedback loop control system that switches between closed-loop ECAP feedback mode and direct current control mode, using a hysteresis function to stabilize stimulation at desired ECAP values, incorporating a filter and selector to adjust stimulus intensity based on measured responses and patient preferences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If closed-loop ECAP feedback control is used to maintain therapeutic stimulation, then stimulation effectiveness is improved, but system stability deteriorates due to meta-stability and oscillations

Engineering Contradiction:

Improvestimulation effectivenessVSAvoidfeedback loop stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

An intermediary switch is introduced between the ECAP feedback controller and the stimulator. This switch acts as a mediator that selectively connects or disconnects the feedback control loop based on operational conditions, allowing the system to benefit from feedback control when stable while avoiding its instabilities when conditions deteriorate

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically transitions between two control modes: closed-loop ECAP feedback control and open-loop control based on patient feedback. This dynamic adaptability allows the system to optimize performance by switching control strategies based on real-time operational stability and patient needs

Inventive Principle:

Principle #15Dynamics

2Reliability

If feedback control is continuously applied to maintain target ECAP values, then neural response consistency is improved, but patient comfort deteriorates due to inability to accommodate changing preferences

Engineering Contradiction:

Improveneural response consistencyVSAvoidpatient preference adaptability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The control system is made dynamic by allowing transitions between automated ECAP feedback control and manual patient-feedback-based control. This enables the system to adapt to changing patient preferences while maintaining neural response consistency when automated control is appropriate

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system incorporates dual feedback mechanisms: ECAP signal feedback for objective neural response monitoring and subjective patient feedback for comfort and preference assessment. Both feedback paths are utilized depending on operational conditions to balance consistency and adaptability

Inventive Principle:

Principle #23Feedback

3Reliability

If stimulus amplitude is increased to ensure therapeutic effect, then pain relief effectiveness is improved, but patient comfort deteriorates due to recruitment of Aδ fibres

Engineering Contradiction:

Improvepain relief effectivenessVSAvoidpatient discomfort

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

ECAP feedback provides real-time information about the neural response to stimulation, allowing the system to adjust stimulus amplitude to the minimum level required for effective pain relief. This prevents excessive stimulation that would recruit painful Aδ fibres while maintaining sufficient activation of therapeutic fibres

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the stimulus amplitude parameter based on ECAP measurements and patient feedback. By continuously optimizing this parameter, the system maintains therapeutic effectiveness while avoiding the discomfort threshold associated with Aδ fibre recruitment

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12533518B2Hybrid feedback loop control of neuromodulation device

Publication Date: 2026.01.27 SALUDA MEDICAL PTY LTD

AI summary

A method of controlling a neural stimulus, the neural stimulus being defined by at least one stimulus intensity parameter. The method comprises, generating a stimulus intensity parameter to control a stimulator that generates a stimulus current for application to a tissue, measuring a response of the tissue, evoked by the stimulus current, determining a response parameter indicative of the measured response, in response to the response parameter being less than a first threshold, setting the stimulus intensity parameter to a desired stimulus intensity level; and in response to the response parameter being greater than a second threshold, adjust the stimulus intensity parameter according to a feedback variable derived from the measured response.