BIMANUAL COORDINATION IN DYSLEXIC ADULTS

Various types of dyslexia have been associated with tactile-motor coor dination deficits and inefficient transfer of information between the two cerebral hemispheres. Twenty-one dyslexic adults were compared to 21 controls on the Bimanual Coordination Task, a test of tactile-motor coordination and interhemispheric collaboration. When compared to con trol subjects, dyslexics showed a consistent pattern of deficits in bi manual motor coordination, both with and without visual feedback. In p articular, dyslexics had greater difficulty relative to normals when t he left hand had to move raster than the right, and when the hands had to make opposite (mirror-image) movements, suggesting problems with i nterhemispheric modulation of visuomotor control. In addition, accurac y on this bimanual coordination task was significantly correlated with the Block Design subtest of the WAIS-R. but not with a rhyme fluency task, suggesting some contribution of right hemisphere controlled visu ospatial skill to performance.