Auditory/visual speech perception by cochlear implant users and hearing aid wearers

This study assessed the auditory/visual speech perception abilities of profoundly hearing-impaired subjects using the cochlear implant (CI) developed at the House Ear Institute with those of patients using traditional hearing aids (HA). Audio-video tape recordings of consonant-vowel-consonants (CVCs) consisting of: ten vowels in the context/mvm/, vowel-consonant-vowels (VCVs) consisting of twenty-four consonants in the context/ C /, and the CID Everyday Sentences were presented through auditory, visual, and auditory-visual modes. Subjects' verbal responses to the stimuli were transcribed by the experimenters. Statistical analyses of the data revealed significant differences for groups, stimuli, and conditions. Inspection of the subject's confusion matrices revealed that both groups used closed-bilabial, velar, dental, labial, and easy to see/hard to see features based on place of articulation in the visual mode. Salient features in the auditory mode for the CI group were duration, sonorancy, and some manner attributes, while the HA subjects used these features as well as sibilancy and voicing. Both groups integrated auditory and visual cues to improve scores in the auditory-visual condition. These findings have implications for future developments of auditory prostheses and auditory rehabilitation programs.