Audiovisual integration and acoustic change complex in adult cochlear implant users: an electrophysiological and...

This study investigated the relationship between audiovisual (AV) integration and acoustic change complex (ACC) responses in cochlear implant (CI) users.

A cross-sectional design was employed. AV integration was assessed with the McGurk paradigm under auditory-only, visual-only, congruent (e.g., auditory /ba/-visual /ba/), and incongruent (e.g., auditory /ba/-visual /ga/) AV conditions. ACC responses were recorded using the /ui/ stimulus. Group comparisons and correlations between AV performance and ACC latencies were analysed.

The study included 25 normal-hearing (NH) adults and 50 CI users (prelingual and postlingual) matched for age and cortical maturation.

NH participants outperformed CI users in auditory-only, congruent, and incongruent AV conditions (p < .05), while visual-only performance was similar (p > .05). CI users showed greater reliance on visual cues and fewer fusion responses under incongruent conditions. ACC latencies were consistently shorter in NH than in CI groups (p < .05). Correlations between ACC latencies and AV performance were observed only in the prelingual CI group, where shorter latencies reflected higher auditory-only accuracy.

CI users exhibited limitations in AV integration and prolonged ACC latencies. Moreover, ACC measures mainly reflect auditory discrimination capacity rather than direct multisensory integration, providing complementary insights into the neural mechanisms underlying speech perception in CI users.