Evoked Neural Response Measurement With Stimulus Artefact Rejection
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Solution Overview
Problem
Existing neuromodulation devices face challenges in accurately measuring evoked neural responses due to contamination from stimulus artefacts, which complicates the maintenance of therapeutic stimulus intensity ranges and leads to uncomfortable or painful side effects from electrode migration and postural changes.
Innovation Solution
The use of a correlation detector with a template orthogonal to the artefact basis to measure evoked neural response intensity, allowing for accurate and robust measurement of neural response characteristics despite stimulus artefacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional measurement methods are used to measure evoked neural responses, then the measurement process is simple, but the measurement precision is poor due to contamination from stimulus artefacts
Solution Approach 1:
The patent extracts and removes the stimulus artefact component from the measured signal by projecting the signal onto an artefact basis and subtracting the projected artefact, leaving only the neural response component for accurate measurement
Solution Approach 2:
The patent segments the measured signal into two distinct components: the stimulus artefact (modeled by an artefact basis) and the neural response, allowing separate processing and measurement of each component
2Reliability
If stimulus intensity is increased to maintain therapeutic effect after electrode migration or postural changes, then the therapeutic effect is maintained, but uncomfortable or painful side effects occur due to over-recruitment of fibres
Solution Approach 1:
The patent implements a feedback mechanism where the measured neural response (after artefact removal) is used to adjust the stimulus intensity, ensuring the stimulus remains within the therapeutic range and preventing over-recruitment that causes discomfort
Solution Approach 2:
The patent makes the stimulus intensity dynamic by continuously adjusting it based on real-time measurement of the neural response, allowing adaptation to electrode migration or postural changes while maintaining therapeutic effectiveness without causing discomfort
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
This method enables precise control of neural recruitment, maintaining stimulus intensity within therapeutic ranges, reducing discomfort, and ensuring consistent therapeutic effects despite electrode migration and postural changes.
Implementation Method 1
measuring an intensity of a neural response evoked by the delivered neural stimulus in the captured signal window by correlating the captured signal window with a template
Data Source
AI summary
Disclosed is an implantable device for controllably delivering neural stimuli. The device comprises: a plurality of electrodes including one or more stimulus electrodes and one or more measurement electrodes; a stimulus source configured to provide neural stimuli to be delivered via the one or more stimulus electrodes to a neural pathway of a patient in order to evoke neural responses from the neural pathway; measurement circuitry configured to capture signal windows sensed on the neural pathway via the one or more measurement electrodes subsequent to respective neural stimuli; and a control unit configured to: control the stimulus source to provide a neural stimulus according to a stimulus intensity parameter; and measure an intensity of an evoked neural response in a signal window capture subsequent to the provided neural stimulus by correlating the captured signal window with a template. The template is orthogonal to a predetermined artefact basis that models an artefact component in the captured signal window.