Medial Olivocochlear Reflex Sound Coding for Noisy Speech
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Solution Overview
Problem
Cochlear implant users face difficulties understanding speech in noisy environments due to the absence of the natural medial olivocochlear reflex, which normally helps in sound localization and noise reduction, leading to compromised speech recognition and sound localization abilities.
Innovation Solution
A bilateral hearing implant system with a channel-specific dynamic inhibition adjustment based on a normalized medial olivocochlear reflex model is employed, adjusting stimulation signals using a channel-specific dynamic inhibition function to mimic the natural reflex, enhancing sound processing by applying larger adjustments for lower frequency bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional cochlear implant signal processing is used, then basic sound perception is achieved, but speech recognition in noisy environments deteriorates due to absence of natural medial olivocochlear reflex
Solution Approach 1:
The patent copies the functional characteristics of the natural medial olivocochlear reflex into the cochlear implant signal processing system. By measuring contralateral ear output energy and applying inhibition adjustments that mirror biological MOCR behavior, the system replicates noise reduction and sound localization capabilities normally provided by the efferent auditory system.
Solution Approach 2:
The system implements feedback by continuously monitoring the output energy of contralateral band pass channels and using this information to dynamically adjust inhibition parameters. This closed-loop approach allows the system to adapt to changing acoustic environments and maintain optimal speech recognition performance.
2Reliability
If channel-specific dynamic inhibition adjustment is applied, then speech recognition in noise improves, but device complexity increases due to additional processing requirements
Solution Approach 1:
The patent segments the auditory spectrum into multiple band pass channels and applies independent inhibition adjustments to each channel based on contralateral energy measurements. This channel-specific approach allows targeted noise reduction while preserving speech information in frequency regions where it is most needed.
Solution Approach 2:
The system dynamically changes inhibition parameters based on measured contralateral output energy levels. By adjusting the inhibition factor c according to the formula involving bandwidth energy ratios, the system adapts its noise reduction strength to match actual acoustic conditions without requiring complex machine learning models.
3Measurement precision
If bandwidth normalization is implemented, then inhibition adjustment accuracy improves, but computational requirements increase
Solution Approach 1:
The patent normalizes bandwidth energy measurements by dividing by the square root of channel bandwidth. This parameter transformation allows accurate comparison of energy levels across channels with different bandwidths while using computationally efficient operations that can be implemented in real-time embedded processors.
Data Source
AI summary
A signal processing arrangement is described for signal processing in a bilateral hearing implant system. A channel compression module develops a inhibition-adjusted band pass signal for each band pass signal using a channel-specific dynamic inhibition adjustment based on a channel-normalized medial olivocochlear reflex model that reflects bandwidth energy for a corresponding contralateral band pass signal and bandwidth energy for a selected reference contralateral band pass signal.