Visual Attention in Deaf Humans: A Neuroplasticity Perspective

Abstract

Deaf people have only an attenuated experience, if any, of hearing. The study of individuals born deaf provides a window onto the role of audition in the functional and cognitive specialization of the brain, as well as onto typical multisensory integration. Deaf individuals allow researchers to ask what happens to the remaining senses in the absence of audition. Research suggests that deaf people do not have enhanced sensory abilities. Rather, the changes appear to be attentional in nature and are related to the recruitment of auditory cortex for visual functions as well as changes in parietal and posterior superior temporal cortices. Studies of deaf adults have led to the proposal they can orient visual attention faster than hearing adults, and that they are better able to process information in the visual periphery. These examples of attentional enhancement are at odds with data from deaf children, who appear to have deficits in sustaining attention and ignoring task-irrelevant distraction. However, adult and child studies often recruit from very different deaf populations. Studies reporting enhancements in deaf adults have typically tested native signers, who were raised in deaf families and exposed to a natural signed language from birth. On the other hand, developmental studies have often focused on deaf children born to hearing parents, who typically experience language delays and associated cognitive deficits as exposure to a natural language is absent at birth and reinstantiated in the first years of life only through cochlear implants or hearing aids.