Cochlear Implant Electrode Array Grouping for High-Rate Stimulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cochlear implants face spatial channel interaction issues due to geometric overlapping of electrical fields, leading to unintended activation of neurons and 'micro-shocks' when switching electrode channels, which limits stimulation rate and precision in representing sound signals.
Innovation Solution
The system assigns electrodes to stimulation groups with varying group stimulation amplitudes based on sound signal characteristics, electrode location, and pulse rates, allowing for higher stimulation rates while minimizing 'micro-shocks' by optimizing electrode activation through predefined groups and sequential or simultaneous stimulation strategies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If stimulation pulses are applied at high rates across multiple electrodes, then temporal representation of sound signals is improved, but spatial channel interaction increases causing unintended neuron activation
Solution Approach 1:
The electrode array is segmented into multiple stimulation groups, where each group contains electrodes that are stimulated simultaneously. By dividing the electrodes into groups and stimulating them in an interleaved manner, the system achieves high overall stimulation rates while maintaining spatial separation between simultaneously active electrodes, thus reducing spatial channel interaction.
Solution Approach 2:
The system employs periodic interleaved stimulation sequences where different stimulation groups are activated in alternating cycles. This periodic action allows high stimulation rates to be achieved over time while ensuring that at any given moment, only electrodes with sufficient spatial separation are active, preventing spatial channel interaction.
2Productivity
If electrode channels are switched rapidly to increase stimulation rate, then temporal representation is improved, but micro-shocks occur causing discomfort
Solution Approach 1:
The system applies compression functions to the envelope signals before converting them to stimulation amplitudes. This beforehand cushioning smooths out rapid transitions in stimulation intensity, preventing the abrupt changes that cause micro-shocks while maintaining high stimulation rates.
Solution Approach 2:
The system dynamically adjusts stimulation parameters including amplitude, pulse width, and rate based on the compressed envelope signals. By changing these parameters smoothly through compression processing, the system achieves high stimulation rates without generating micro-shocks that would cause discomfort.
3Device complexity
If each electrode addresses a broad frequency band, then device complexity is reduced, but measurement precision of sound signal characteristics decreases
Solution Approach 1:
The system adds the temporal dimension to frequency analysis by applying compression functions to envelope signals in the time domain. This allows broad frequency bands to be processed with high temporal precision, achieving both low device complexity and high measurement precision by operating in multiple dimensions simultaneously.
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 enables higher stimulation rates with reduced 'micro-shocks' and maintains constant activity in all cochlear regions, improving temporal representation of sound signals and mimicking natural hearing more effectively.
Implementation Method 1
An implanted stimulator 105 generates a stimulation signal in the form of electrical pulses that are sent to electrodes in an implanted electrode array 107 that extends into the scala tympani 109 in the inner ear. Activation of the electrodes with the pulses stimulates the adjacent audio nerve tissue.
Implementation Method 2
Spatial channel interaction means that there is considerable geometric overlapping of electrical fields at the location of the excitable nervous tissue, if different stimulation electrodes (positioned in the scala tympani) are activated. Thus the same neurons are activated if different electrodes are stimulated. Spatial channel interaction is primarily due to the conductive fluids and tissues surrounding the stimulation electrode array.
Data Source
AI summary
A system and method for activating electrodes in an implanted electrode array with a stimulation signal is described. A stimulation definition stage, for each of a plurality of defined sound signal characteristics (C), assigns each electrode to one of a plurality of stimulation groups (G) each having an associated group stimulation amplitude function (A), where (G) varies with (C). An electrode stimulator activates each electrode as the stimulation signal varies based on spectral components of the stimulation signal.