Effect of adaptive envelope compression in simulated electric hearing in reverberation

The narrow dynamic range for speech perception partially accounts for the poor speech understanding abilities of hearing-impaired patients fitted with cochlear implants, particularly in challenging listening conditions, e.g., in reverberation. Wide dynamic range compression is designed to compress speech signal into the usable hearing dynamic range of implanted patients; however, it normally uses a static compression based strategy. An adaptive envelope compression (AEC) strategy was recently proposed for speech processing in cochlear implants. It implemented the envelope compression as close to linear as possible, while confined the compressed amplitude envelope within the pre-set dynamic range. This study further assessed its effect to improve speech perception in reverberation. Vocoder simulation experiment showed that, when narrowed down to a small dynamic range, the AEC-processed sentences could yield a higher intelligibility score in reverberation than the static compression processed sentences.