Influences of age at onset of blindness on Braille reading performances with left and right hands.

Several previous studies suggest that early sensory deprivation produces a changed organisation of the cerebral cortex. This study compared the effects of early and late total blindness on a Braille reading task. This task is intended to induce a superiority of the left hand rather than the right because of the particular role played by the right hemisphere in Braille decoding. 38 strongly right-handed adults, accustomed to daily bimanual Braille reading, were tested. 21 subjects were born blind and 17 became blind during childhood before learning to read. Analysis indicated that previous visual experience can, under certain conditions, play a modulating role in manual superiority in Braille reading.