Cochlear Implant Loudness Mapping With Adaptive Knee Points
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Solution Overview
Problem
Conventional cochlear implants lack adaptive signal processing techniques to effectively map acoustic energy to electrical stimulation, failing to provide a realistic loudness experience in varying environments, particularly for speech recognition.
Innovation Solution
The cochlear implant employs an enhanced mapping function with an intermediate knee point, allowing for level expansion below the threshold and level compression above it, dynamically adjusting electrical stimulation based on the user's environment through a signal level detector and processing unit, which determines the intermediate knee point for each frequency band to enhance speech information and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional amplitude mapping is used to convert acoustic signals to electrical stimulation, then the basic hearing function is restored, but the loudness mapping is not adaptive to varying environments resulting in unrealistic loudness experience
Solution Approach 1:
The mapping function dynamically adjusts the knee point based on the detected signal level. When the signal level exceeds the knee point, the mapping adapts by raising the knee point to a higher level, allowing the system to maintain optimal performance across varying acoustic environments rather than being fixed to a single mapping configuration.
Solution Approach 2:
The system continuously monitors the input signal level and uses this feedback to adjust the knee point position in real-time. This feedback mechanism enables the mapping function to adapt to changing environmental conditions, improving the realism of loudness perception without requiring manual reconfiguration.
2Adaptability or versatility
If the entire length of the cochlea is stimulated to provide full frequency range, then hearing coverage is maximized, but speech recognition in noisy environments deteriorates due to lack of selective speech enhancement
Solution Approach 1:
The system applies different processing characteristics to different portions of the acoustic signal spectrum. By identifying speech-relevant frequency ranges and applying enhanced processing to these specific bands while using standard processing for other frequencies, the system selectively enhances speech information without compromising overall hearing coverage.
Solution Approach 2:
The mapping function dynamically adjusts the knee point based on the detected signal level. When the signal level exceeds the knee point, the mapping adapts by raising the knee point to a higher level, allowing the system to maintain optimal performance across varying acoustic environments rather than being fixed to a single mapping configuration.
3Ease of operation
If linear amplitude mapping is used, then the system is simple to implement, but drastic loudness changes occur in noisy conditions reducing user comfort
Solution Approach 1:
The mapping function dynamically adjusts the knee point based on the detected signal level. When the signal level exceeds the knee point, the mapping adapts by raising the knee point to a higher level, allowing the system to maintain optimal performance across varying acoustic environments rather than being fixed to a single mapping configuration.
Data Source
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AI summary
A cochlear implant is disclosed in an embodiment. The implant includes a signal level detector configured to determine a total signal level of an incoming acoustic signal and a processing unit configured to determine, in accordance with the determined total signal level, an intermediate knee point for each of a plurality of frequency bands. The implant includes a bandpass filters configured to generate a plurality of band limited audio signals in dependence upon the incoming acoustic signal, each band limited acoustic signal representing an associated audio frequency range relating to at least one electrode of a plurality of an implanted electrode array of the cochlear implant. The implant includes a pulse controller configured to deliver electrical stimulation signals to the plurality of electrodes of the implanted electrode array based on the generated signals and the determined intermediate knee point corresponding to the frequency range.