Cochlear Implant Signal Processing for Temporal Resolution
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Solution Overview
Problem
Cochlear implant systems often fail to provide clear sound perception due to inefficient sound processing strategies, leading to suboptimal clarity and temporal resolution.
Innovation Solution
Dynamic selection of channels for stimulation based on spectral power, where only channels with spectral power above a threshold are stimulated, and stimulation is removed from channels with low spectral power, enhancing contrast and temporal resolution while reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If stimulation is applied to multiple channels simultaneously, then the coverage of sound frequencies is improved, but the temporal resolution and spectral contrast deteriorate
Solution Approach 1:
The patent implements continuous interleaved sampling (CIS) where stimulation is delivered in periodic sequences across multiple channels rather than simultaneously. Each channel receives stimulation in alternating time slots, creating a periodic pattern that maintains temporal resolution while covering multiple frequency bands over time.
Solution Approach 2:
The system dynamically adjusts the number of active channels based on spectral power analysis. The processor identifies channels with significant spectral power and activates only those channels for stimulation, while keeping other channels inactive. This dynamic adaptation optimizes temporal resolution by reducing the number of simultaneously stimulated channels while maintaining comprehensive frequency coverage when needed.
2Adaptability or versatility
If stimulation is applied to all available channels, then the spectral coverage is improved, but the perceived loudness and spectral contrast deteriorate
Solution Approach 1:
The patent applies local quality by differentiating between channels based on their spectral power characteristics. Channels with high spectral power receive stimulation with higher intensity and faster presentation rates, while channels with low spectral power receive reduced or no stimulation. This creates localized optimization where each channel's stimulation parameters are tailored to its specific spectral contribution.
Solution Approach 2:
The system changes stimulation parameters (pulse rate, intensity) based on the spectral power of each channel. Channels above a threshold spectral power level receive enhanced stimulation parameters including faster presentation rates, which increases perceived loudness and spectral contrast for those specific channels while maintaining overall spectral coverage.
3Measurement precision
If the number of stimulated channels is increased, then the frequency resolution is improved, but the temporal resolution and power efficiency deteriorate
Solution Approach 1:
The system applies partial action by stimulating only the necessary subset of channels at any given time rather than all channels simultaneously. Based on spectral power analysis, the processor identifies and activates only those channels that contribute significantly to the sound signal, leaving other channels inactive. This partial stimulation maintains frequency resolution for the active channels while improving temporal resolution through reduced channel count.
4Adaptability or versatility
If stimulation is applied to all channels, then the sound coverage is improved, but the power consumption increases
Solution Approach 1:
The patent extracts and removes stimulation from channels that contribute minimally to the sound signal. By analyzing spectral power and identifying channels below a threshold level, the system extracts these low-contribution channels from the active stimulation set. This removal reduces power consumption while maintaining sound coverage through the remaining high-contribution channels.
Data Source
AI summary
A cochlear implant processing strategy increases speech clarity and provides higher temporal performance. The strategy determines the power spectral component within each channel, and dynamically selects or de-selects the channels through which a stimulation pulse is provided as a function of whether the spectral power of the channel is high or low. “High” and “low” are estimated relative to a selected spectral power, for example. The selected spectral power can be estimated by signal average or mean, or by other criteria. Once a selection of the channels to stimulate has been made, the system can decide that only those channels are stimulated, and stimulation is removed from the other channels. The selected channels are the ones on which the spectral power is above the mean of all the available channels. Fewer channels are stimulated at any time and the contrast of the stimulation is enhanced. Also, the temporal resolution increases as the number of channels that must be stimulated on a given frame decreases. This way, the channels which are presented to the patient are fewer in number and contain more temporal information.