The superiority in voice processing of the blind arises from neural plasticity at sensory processing stages

Neuropsychologia. 2012 Jul;50(8):2056-67. doi: 10.1016/j.neuropsychologia.2012.05.006. Epub 2012 May 12.

Abstract

Blind people rely much more on voices compared to sighted individuals when identifying other people. Previous research has suggested a faster processing of auditory input in blind individuals than sighted controls and an enhanced activation of temporal cortical regions during voice processing. The present study used event-related potentials (ERPs) to single out the sub-processes of auditory person identification that change and allow for superior voice processing after congenital blindness. A priming paradigm was employed in which two successive voices (S1 and S2) of either the same (50% of the trials) or different actors were presented. Congenitally blind and matched sighted participants made an old-young decision on the S2. During the pre-experimental familiarization with the stimuli, congenitally blind individuals showed faster learning rates than sighted controls. Reaction times were shorter in person-congruent trials than in person-incongruent trials in both groups. ERPs to S2 stimuli in person-incongruent as compared to person-congruent trials were significantly enhanced at early processing stages (100-160 ms) in congenitally blind participants only. A later negative ERP effect (>200 ms) was found in both groups. The scalp topographies of the experimental effects were characterized by a central and parietal distribution in the sighted but a more posterior distribution in the congenitally blind. These results provide evidence for an improvement of early voice processing stages and a reorganization of the person identification system as a neural correlate of compensatory behavioral improvements following congenital blindness.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acoustic Stimulation
  • Adult
  • Auditory Perception / physiology*
  • Blindness / congenital*
  • Case-Control Studies
  • Discrimination Learning
  • Electroencephalography
  • Evoked Potentials, Auditory / physiology*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Neuronal Plasticity*
  • Pattern Recognition, Physiological / physiology*
  • Reaction Time
  • Repetition Priming
  • Visually Impaired Persons
  • Voice*