Audio-visual integration during speech perception in prelingually deafened Japanese children revealed by the McGurk effect.

Objective: To investigate the McGurk effect in profoundly deafened Japanese children with cochlear implants (CI) and in normal-hearing children. This was done to identify how children with profound deafness using CI established audiovisual integration during the speech acquisition period.

Methods: Twenty-four prelingually deafened children with CI and 12 age-matched normal-hearing children participated in this study. Responses to audiovisual stimuli were compared between deafened and normal-hearing controls. Additionally, responses of the children with CI younger than 6 years of age were compared with those of the children with CI at least 6 years of age at the time of the test.

Results: Responses to stimuli combining auditory labials and visual non-labials were significantly different between deafened children with CI and normal-hearing controls (p<0.05). Additionally, the McGurk effect tended to be more induced in deafened children older than 6 years of age than in their younger counterparts.

Conclusions: The McGurk effect was more significantly induced in prelingually deafened Japanese children with CI than in normal-hearing, age-matched Japanese children. Despite having good speech-perception skills and auditory input through their CI, from early childhood, deafened children may use more visual information in speech perception than normal-hearing children. As children using CI need to communicate based on insufficient speech signals coded by CI, additional activities of higher-order brain function may be necessary to compensate for the incomplete auditory input. This study provided information on the influence of deafness on the development of audiovisual integration related to speech, which could contribute to our further understanding of the strategies used in spoken language communication by prelingually deafened children.