Cochlear Implant Electrode Array Windowed Stimulation
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Solution Overview
Problem
Current cochlear implant stimulation strategies either discard temporal fine structure and instantaneous frequency, leading to poor perception of interaural time differences and pitch, or generate electrical field overlaps that degrade these cues, while also having high power consumption issues.
Innovation Solution
A windowed stimulation strategy is implemented for a subgroup of electrodes, where only one or non-adjacent electrodes are active at a time, using analog waveforms or pulse trains amplitude-modulated by the input signal, to preserve temporal fine structure and avoid spectral overlap, while reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If simultaneous analog stimulation is used for all electrodes, then temporal fine structure and instantaneous frequency are preserved, but electrical field overlaps between adjacent electrodes occur which degrades these cues
Solution Approach 1:
The patent implements a windowing function that periodically activates different electrode groups in a cyclic manner. Each electrode or electrode group receives stimulation signals in alternating time windows, creating a periodic stimulation pattern that preserves temporal fine structure while preventing simultaneous activation of adjacent electrodes that would cause electrical field overlap.
2Loss of information
If simultaneous analog stimulation is used for all electrodes, then temporal fine structure is preserved, but power consumption increases significantly
Solution Approach 1:
The windowing function creates periodic stimulation patterns where electrodes are activated in alternating time windows rather than continuously. This temporal separation reduces the overall power consumption while maintaining temporal fine structure preservation during active stimulation periods, as not all electrodes draw power simultaneously.
3Object-generated harmful factors
If non-simultaneous coding strategies are used, then electrode separation is improved, but temporal fine structure and instantaneous frequency are not preserved
Solution Approach 1:
The patent merges the advantages of both simultaneous analog stimulation and non-simultaneous coding by combining continuous analog waveforms with a windowing function. The analog waveforms preserve temporal fine structure while the windowing function provides temporal separation similar to non-simultaneous coding, creating a hybrid approach that achieves both goals.
Solution Approach 2:
The patent employs dynamic windowing where the activation pattern of electrodes changes over time based on the windowing function. This dynamic temporal modulation allows the system to switch between different electrode activation states, preserving temporal fine structure through analog waveforms while preventing electrical field overlap through time-varying activation patterns.
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 approach allows for improved perception of interaural time differences and pitch, enhancing speech understanding in noise and localization, particularly at frequencies below 1.5 kHz, while minimizing power consumption and avoiding electrode overlap.
Implementation Method 1
pulse trains having an amplitude modulated by an amplitude of a waveform of the input signal of a respective input signal channel associated with the respective stimulation channel
Data Source
AI summary
An exemplary cochlear implant system comprises an electrode array comprising a plurality of stimulation electrodes; a frequency filtering unit configured to divide an input audio signal into a plurality of input signal channels; and a stimulation control unit configured to generate from the plurality of input signal channels a dedicated stimulation signal for each of a plurality of stimulation channels, each stimulation channel being associated with one of the electrodes. The stimulation control unit is further configured to provide at least a subgroup of electrodes with stimulation signals, each of which is windowed in such a manner that at a time only to one of the electrodes of the subgroup, or only to non-adjacent electrodes of the subgroup, an active window is awarded during which the respective electrode is supplied with stimulation current. The stimulation signals of the electrode subgroup comprise (i) analog waveforms or wavelets which each correspond to a waveform of the input signal of a respective input signal channel associated with the respective stimulation channel, or (ii) pulse trains having an amplitude modulated by an amplitude of a waveform of the input signal of a respective input signal channel associated with the respective stimulation channel.