Audiovisual Integration Function Measured by McGurk Effect Correlates to the Auditory Performance in CI Users

摘要

With given auditory input degraded, cochlear implant (CI) users depend on visual information more than normal hearing people do. Recent studies have shown that CI users were equipped with better multisensory integration function than normal hearing persons and this compensatory multisensory processing have developed as the period of CI usage increased. However, the behavioral benefit of enhanced multisensory integration has not been clarified yet. Audio-visual intergration function was tested in eleven postlingually deaf CI users using McGurk stimulus which was composed of auditory/ba/ with visual/ga/ simultaneously, that produces normally McGurk illusory percept of /da/ in normal controls. With 10 McGurk stimuli, auditory/ba/, auditory/ ga/, visual/ba/, visual/ga/, audiovisual/ba/, and audiovisual/ga/ were randomly presented for 10 times each. Contrary to the normal controls, most of errors from CI users were made following the visual information of the stimuli. The percentage of correct responses (fused percept) to the McGurk stimuli correlated positively to the phoneme scores in auditory only condition tested in the clinic. This study suggests a role of multisensory integration in improving auditory performance in everyday life and proposes rehabilitation program focusing not only to improve auditory skill, but also to enhance audiovisual integration function.