Neural Stimulation Feedback Control for Electrode Movement
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Solution Overview
Problem
Neuromodulation systems face challenges in maintaining effective and comfortable neural recruitment due to changes in electrode position and patient posture, leading to variations in stimulus amplitude and recruitment thresholds, which affect therapeutic efficacy and cause side effects.
Innovation Solution
A feedback loop system that adaptively compensates for changes in electrode movement relative to the neural pathway by measuring compound action potentials and adjusting stimulus parameters to maintain consistent neural recruitment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If fixed current stimulation is delivered to the dorsal column, then the stimulation system is simple to operate, but the neural recruitment varies due to electrode movement and posture changes
Solution Approach 1:
The system measures the evoked compound action potential (ECAP) amplitude and uses this feedback to automatically adjust the stimulus amplitude, maintaining consistent neural recruitment despite electrode movement or posture changes. The feedback loop continuously monitors ECAP and modifies stimulation parameters to keep the neural response within the therapeutic window.
Solution Approach 2:
The stimulation system performs self-adjustment by automatically modifying its own stimulus amplitude based on real-time ECAP measurements, eliminating the need for manual reconfiguration by the operator when posture or electrode position changes.
2Reliability
If stimulus amplitude is increased to maintain neural recruitment, then therapeutic efficacy is improved, but uncomfortable side effects increase
Solution Approach 1:
The system uses ECAP amplitude as a feedback signal to precisely control stimulus amplitude, ensuring it remains within the optimal therapeutic range. By maintaining ECAP within a target range, the system achieves reliable pain relief while avoiding over-stimulation that causes discomfort or paresthesia.
Solution Approach 2:
The system dynamically adjusts the stimulus amplitude parameter based on measured ECAP values, changing it in real-time to maintain optimal neural recruitment without exceeding comfort thresholds. This adaptive parameter control prevents both under-stimulation and over-stimulation.
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 and comfortable neural stimulation by maintaining evoked compound action potential amplitude, reducing variations in therapeutic efficacy and side effects across different postures.
Implementation Method 1
measurement circuitry for recording a neural compound action potential signal sensed at the one or more sense electrodes
Implementation Method 2
a stimulus source for providing a stimulus to be delivered from the one or more stimulus electrodes to a neural pathway in order to give rise to an evoked action potential on the neural pathway
Data Source
AI summary
A method of controlling a neural stimulus by use of feedback. The neural stimulus is applied to a neural pathway in order to give rise to an evoked action potential on the neural pathway. The stimulus is defined by at least one stimulus parameter. A neural compound action potential response evoked by the stimulus is measured. From the measured evoked response a feedback variable is derived. A feedback loop is completed by using the feedback variable to control the at least one stimulus parameter value. The feedback loop adaptively compensates for changes in a gain of the feedback loop caused by electrode movement relative to the neural pathway.