Cortical Entrainment to Speech Produced by Cochlear Implant Users and Normal-Hearing Talkers

Area of Science:

• Neuroscience
• Audiology
• Speech Science

Background:

• Hearing loss significantly impacts speech sound quality.
• Cochlear implants (CIs) aid hearing but do not fully restore normal speech perception.
• Speech produced by CI users often differs in quality from that of normal-hearing (NH) individuals.

Purpose of the Study:

• To investigate cortical activity differences in NH listeners processing speech from CI versus NH talkers.
• To correlate objective measures of cortical entrainment with subjective sound quality ratings.

Main Methods:

• Recorded electroencephalogram (EEG) from NH listeners exposed to continuous speech from 8 CI and 8 NH talkers.
• Used a discriminative model to decode and reconstruct the speech envelope from single-trial EEG.
• Calculated correlation coefficients between reconstructed and original speech envelopes.
• Collected behavioral ratings of perceived speech sound quality.

Main Results:

• Cortical entrainment to the speech envelope was significantly lower for speech from CI talkers compared to NH talkers.
• NH listeners rated the perceived sound quality of speech from CI talkers lower than from NH talkers.
• Both objective (EEG-based) and subjective measures indicated differences in speech processing.

Conclusions:

• NH listeners exhibit distinct neural processing patterns when listening to CI-generated speech.
• Differences in speech production by CI users affect both neural encoding and subjective perception.
• Further research is needed to understand and potentially mitigate these differences for improved CI user communication.