Bimanual co-ordination in adolescent boys with reading retardation.

The temporal organization of unimanual and bimanual rhythmic finger-tapping was compared between adolescent normal readers and retarded readers, as well as across subgroups of retarded readers with different psychometric intelligence profiles. Regardless of subtype, the retarded readers had substantially greater difficulty in maintaining a steady tapping rhythm than did controls, but their deficit was limited to motor tasks requiring asymmetrical timing commands to the two hands. The findings indicate that the motor deficits of retarded readers on complex skills persist into adolescence; and they suggest that one major source of difficulties in motor performance may be in rapid communication between the hemispheres.