Binaural Cue Conversion for Cochlear Implant Signal Processing
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Solution Overview
Problem
Hearing-impaired individuals, especially those with bilateral cochlear implants, face challenges in localizing sounds and understanding speech in noisy environments due to limited access to binaural cues, as they primarily receive interaural level differences (ILDs) and not interaural time differences (ITDs), and their binaural representation is inconsistent across frequencies, leading to poor sound localization and spatial release from masking.
Innovation Solution
A method that estimates ITDs from sound signals received by bilateral cochlear implants and converts them into ILDs, adjusting the signals to enhance the binaural representation by attenuating the contralateral ear, thereby improving the signal-to-noise ratio and allowing for better sound localization and speech understanding in noisy conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bilateral cochlear implants are implanted to provide binaural hearing, then the ability to perceive sound in both ears is improved, but the access to binaural cues (ITDs and ILDs) remains limited and inconsistent across frequencies
Solution Approach 1:
The patent transforms ITD information into ILD representations through signal processing. Specifically, it estimates ITDs from the signals received by bilateral cochlear implants and then converts these ITD estimates into corresponding ILD values, creating a consistent binaural representation across all frequency bands where ILDs are normally available
Solution Approach 2:
The patent introduces an intermediate processing step that converts ITD estimates into ILD representations. This intermediary transformation allows the system to utilize ITD information (which is available across all frequencies) while presenting it in the ILD format that cochlear implant users can effectively process
2Reliability
If signal processing is applied to enhance binaural representation, then speech intelligibility in noise is improved, but the complexity of the device increases
Solution Approach 1:
The patent performs preliminary estimation of ITDs from the bilateral cochlear implant signals before converting them to ILDs. By pre-calculating the ITD information and storing it for subsequent conversion, the system avoids redundant calculations and reduces overall processing complexity
Solution Approach 2:
The patent processes different frequency bands separately, estimating ITDs and converting to ILDs for each frequency band independently. This segmentation allows the complex processing to be broken down into manageable frequency-specific operations that can be implemented efficiently
3Reliability
If ITDs are converted to ILDs to enhance binaural representation, then spatial release from masking is improved, but the natural binaural cue representation is altered
Solution Approach 1:
The patent deliberately changes the binaural cue representation from ITD-based to ILD-based format. By converting ITD estimates into corresponding ILD values, the system transforms the nature of the binaural information while preserving the spatial localization data in a format that is consistently available across all frequency bands for cochlear implant users
Data Source
AI summary
A method of enhancing binaural representation for a subject includes receiving a first signal and a second signal in response to a plurality of sound sources, generating a number of estimated interaural time differences using the first signal and the second signal, converting each of the number of estimated interaural time differences to a corresponding interaural level difference, using one or more of the corresponding interaural level differences to generate an adjusted first signal, and using the adjusted first signal to generate a number of signals delivered to the subject for enhancing the hearing of the subject.