Examining influences of deafness on behavioral and cortical responses to vibrotactile speech stimuli.

Abstract

Deaf individuals can rely on somatosensation for the perception of acoustic stimuli. Research into both natural and artificial approaches to support this sensory substitution has led to the observation of enhanced vibrotactile processing in some deaf individuals. Two fundamental questions arise related to this observation. First, what in the experience of deafness could have led to the enhancement of somatosensory processing? Second, what, if any, cortical changes are associated with the processing of somatosensory stimuli in deaf individuals? With regard to the first question, evidence will be presented that suggests that the enhancement may arise as a result of the significant amounts of vibrotactile stimulation some deaf individuals receive from wearing high‐powered hearing aids. With regard to the second question, evidence will be presented that suggests that life‐long experience with high‐powered hearing aids is also associated with the observation of auditory cortex activation by somatosensory stimuli in deaf individuals. Taken together these results support experience driven changes in somatosensory processing of acoustic speech stimuli and associate auditory cortex activation with these changes. These results will be discussed within the context of implications for multisensory processing following cochlear implantation.