A neurophysiological basis of developmental dyslexia

Recent advances in the understanding of the asymmetrical functions of the cerebral hemispheres provide new insight to the mechanisms underlying the developmental language disorders. It is probable that learning to read depends in part upon the ability to establish an association between a seen object (customarily perceived within the right hemisphere) and a verbal symbol (mediated by the left). It is possible that as the reading skill develops, verbal symbol recognition may also become a left hemisphere function. A complex interaction between the two developing hemispheres is involved. A clue to the nature of this problem is that developmental dyslexia is six times more common in boys than in girls. Studies defining differences in cerebral dominance in boys and girls will be reviewed in this context.