Abstract
Objectives:
We created a vowel perception test to analyze the contribution of visual and auditory inputs during vowel processing in cochlear implant (CI) users.
Methods:
We enrolled 30 adults and 40 children who received cochlear implants (CI). Ten adults and 11 children with normal hearing (NH) also participated as controls. The auditory stimuli were 5 Japanese vowels and the visual stimuli were apparent motions that were succeeded by pictures of faces. The following three test conditions were used: 1) AV, the matched pairs of visual and auditory stimuli, 2) AV-mismatch, the inconsistent pairs of stimuli, and 3) A-only. During the session, the subjects were instructed to judge which vowel was said and to press the correct button. Correct rate and reaction time were measured.
Results:
Correct rate in AV-mismatch and A-only condition was significantly higher in NH compared to CI. Correct rate of AV-mismatch condition was significantly lower than that of AV and A-only conditions in CI. Moreover, CI took longer reaction time in AV-mismatch condition compared to other conditions. We found that the degree of visual dependence of adult CI users was correlated with speech discrimination score, but not age, duration of deafness, or duration of CI use. Among pediatric CI users, mode of communication during preschool period affected the results.
Conclusions:
The aural group showed results similar to those of adult CI users, which imply that their processing of visual and auditory inputs is close to those who learned speech and language through the auditory modality.
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