gms | German Medical Science

Hearing loss and cochlear implantation induce functional changes in the auditory cortex, which even extend to other cortical regions, including but not limited to the visual cortex [1]. These changes seem to represent compensatory strategies which allow the individual to overcome the limitations in hearing function. Indeed, studies with CI users have shown better visual abilities, for instance higher lip-reading skills, when compared with normal-hearing (NH) listeners [2]. However, there is increasing evidence that cortical changes induced by hearing loss and cochlear implantation also affect the interactions between the auditory and the visual modality. Behavioral results have indicated that CI users show a strong bias to the visual aspects of audio-visual speech [2]. Further, studies using electroencephalography (EEG) have revealed that CI users show stronger activation in the auditory cortex during visual and audio-visual information processing when compared with NH individuals ([1]; [3]). These cortical alterations may allow better lip-reading abilities and enhanced audio-visual integration skills in CI users [2]. This view is supported by our recent observation, that CI users – when compared with NH listeners – show altered processing of audio-visual (environmental) objects, and enhanced audio-visual benefit for the later (unisensory) auditory object recognition (in preparation). The observation of altered audio-visual information processing and enhanced audio-visual integration skills in CI users suggests that hearing loss and/or cochlear implantation significantly affect the interactions between the auditory and the visual modality. In addition to the aforementioned results, the talk is going to present preliminary results from ongoing EEG studies which explore audio-visual interactions during the processing of two-syllabic words at different stages following CI-rehabilitation. Further, the clinical implications of altered audio-visual interactions in CI users will be discussed.