A number of studies have documented that changes in visual cognition following profound deafness are highly specific. Among these, deaf individuals have proved to have enhanced visual ability compared to hearing controls when asked to rapidly detect the onset of abrupt visual stimuli, particularly when presented towards the periphery of the visual field.
However, no study to date has addressed the question of whether visual compensatory changes may be reversed after reafferentation of the auditory system through a cochlear implant. To address this question, we measured reaction times to visually presented stimuli appearing in central and peripheral locations in two groups of adult cochlear implant recipients, who experienced auditory loss either early or late in life. Results showed that prelingually deafened recipients were faster than postlingually deafened recipients for stimuli appearing in the periphery of the visual field. On the contrary, postlingually deafened individuals paid a cost for stimuli presented in the periphery of the visual field, as typically found in hearing controls adopting identical task and stimuli. These findings lead to suggestion that compensatory changes that occur early in life cannot be reversed in adulthood in case of sensory reafferentation.