Cochlear Implant Pulse Weighting for Low Frequency Channel Privilege
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Solution Overview
Problem
Cochlear implants face challenges with spatial channel interaction, where multiple stimulation electrodes activated simultaneously cause significant geometric overlapping of electrical fields, leading to 'micro-shocks' and dominance of higher frequency channels over low frequency channels, which affects speech perception and understanding.
Innovation Solution
A system that processes acoustic signals using a preprocessor filter bank to generate band pass signals, an information extractor to define stimulation event signals, and a pulse selector that uses channel-specific weighting factors to favor lower frequencies, allowing for sequential or simultaneous activation of stimulation electrodes, thereby minimizing spatial channel interaction and ensuring constant activity in all cochlear regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple stimulation electrodes are activated simultaneously, then higher stimulation rates can be achieved, but spatial channel interaction occurs causing geometric overlapping of electrical fields and micro-shocks
Solution Approach 1:
The patent applies periodic action by using intermittent stimulation patterns where electrodes are activated in alternating cycles rather than continuously. The stimulator delivers stimulation pulses at varying rates including periods of activity and rest, which reduces cumulative spatial channel interaction while maintaining adequate overall stimulation rates for speech perception.
Solution Approach 2:
The patent implements preliminary action through pre-processing of acoustic signals before stimulation delivery. An external preprocessor filter bank analyzes the acoustic signal and generates band-pass signals that are then used to control stimulation timing, allowing the system to anticipate and prepare stimulation patterns that minimize spatial channel interaction before electrodes are activated.
2Reliability
If higher frequency channels are prioritized in stimulation, then speech perception may improve, but low frequency channel information is lost affecting speech understanding
Solution Approach 1:
The patent applies local quality by assigning different stimulation priorities to different frequency channels based on their specific characteristics. Low frequency channels receive different weighting and stimulation patterns compared to high frequency channels, with each channel's stimulation optimized for its specific frequency range and informational importance for speech understanding.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting stimulation parameters including pulse amplitude, duration, and timing based on the instantaneous characteristics of each frequency channel. The system varies stimulation parameters in real-time to preserve low frequency information while maintaining overall speech perception quality.
3Device complexity
If stimulation pulses are applied at constant rate across all electrodes, then device complexity is reduced, but temporal representation of envelope signal becomes insufficient
Solution Approach 1:
The patent applies dynamics by transitioning from static constant-rate stimulation to dynamic electrode-specific stimulation rates. Each electrode can operate at different stimulation rates tailored to its frequency channel characteristics and the instantaneous signal envelope, allowing precise temporal representation while the overall system maintains manageable complexity through systematic control strategies.
Data Source
AI summary
A system and method for activating stimulation electrodes in cochlear implant electrode is described. A preprocessor filter bank processes an input acoustic audio signal to generate band pass signals that each represent an associated band of audio frequencies. An information extractor extracts stimulation signal information from the band pass signals based on assigning the band pass signals to corresponding electrode stimulation groups that each contain one or more stimulation electrodes, and generates a set of stimulation event signals for each electrode stimulation group that define electrode stimulation timings and amplitudes. A pulse selector selects a set of electrode stimulation signals from the stimulation event signals based on a pulse weighting function that uses channel-specific weighting factors favoring lower frequencies for activating the stimulation electrodes to stimulate neighboring audio nerve tissue.