Bilateral Cochlear Implant Interaural Coherence Analysis

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Solution Overview

Problem

Current cochlear implant systems face limitations in sound localization and speech understanding in noisy and reverberant conditions due to the non-adaptive use of temporal fine structure information, which is affected by noise and reverberation, and do not effectively handle echoes or secondary sound sources.

Innovation Solution

A bilateral hearing implant system that incorporates an interaural coherence analysis module to adaptively process microphone signals and generate stimulation timing signals using an envelope gating function, allowing for seamless switching between event-based and envelope-based coding strategies based on signal-to-noise ratio (SNR) and interaural coherence, enhancing sound localization and speech perception.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If temporal fine structure information is used for coding, then sound localization capability is improved, but performance in noisy and reverberant conditions deteriorates

Engineering Contradiction:

Improvesound localization accuracyVSAvoidspeech understanding in noisy conditions

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system dynamically switches between coding strategies based on listening conditions. An interaural coherence analysis module continuously evaluates the acoustic environment and adaptively selects between temporal fine structure-based coding (for sound localization in quiet conditions) and envelope-based coding (for speech understanding in noisy conditions), making the system flexible and condition-optimal

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the coding parameter based on environmental conditions. When interaural coherence is high (quiet conditions), temporal fine structure information is prioritized for accurate sound localization. When interaural coherence is low (noisy/reverberant conditions), the system switches to envelope-based coding to maintain speech understanding performance

Inventive Principle:

Principle #35Parameter changes

2Reliability

If envelope-based coding is used, then speech understanding in noisy conditions is improved, but sound localization capability deteriorates

Engineering Contradiction:

Improvespeech understanding in noisy conditionsVSAvoidsound localization accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system dynamically adjusts the coding strategy based on real-time analysis of interaural coherence. In noisy conditions where envelope-based coding provides better speech understanding, the system switches to this mode while preserving the ability to revert to temporal fine structure coding when conditions improve, ensuring optimal performance across varying environments

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The coding parameter is changed from temporal fine structure to envelope representation when noisy conditions are detected. This parameter change prioritizes speech understanding reliability while the system maintains the capability to switch back when sound localization becomes more critical

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If adaptive switching between coding strategies is implemented, then overall auditory perception is improved, but device complexity increases

Engineering Contradiction:

Improveperformance across listening conditionsVSAvoidsignal processing complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The signal processing is segmented into distinct modules: an interaural coherence analysis module that evaluates listening conditions, and separate coding strategy modules for temporal fine structure and envelope-based coding. This segmentation allows independent optimization of each module and simplifies the adaptive switching logic

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An interaural coherence analysis module serves as an intermediary that assesses the acoustic environment and mediates the selection between coding strategies. This intermediary simplifies the decision-making process by providing a clear metric (interaural coherence) that directly guides the switching between temporal fine structure and envelope-based coding

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9776001B2Interaural coherence based cochlear stimulation using adapted envelope processing

Publication Date: 2017.10.03 MED EL ELEKTROMEDIZINISCHE GERAETE GMBH

AI summary

A signal processing system is described for a bilateral hearing implant system having left side and right side hearing implants. An interaural coherence analysis module receives input signals from each hearing implant including sensing microphone signals and band pass signals, and analyzes the input signals to produce an interaural coherence signal output characterizing reverberation-related similarity of the input signals. A pulse timing and coding module for each hearing implant then processes the band pass signals to develop stimulation timing signals, wherein for one or more selected band pass signals, wherein the processing includes using an envelope gating function developed from the interaural coherence signal.