Developmental apraxia of speech and manual dexterity.

A quantitative test of fine motor function was used to compare the dexterity of the right and left hands of normal children and children with developmental apraxia of speech (DAS). The results suggest that the left cerebral hemisphere of children with DAS is not predominantly impaired in regard to motor control of the upper extremities. In neither female nor male children with DAS was the manual dexterity of the right hand less than that of the left. In female but not male children with DAS, manual dexterity of both hands was impaired when compared to the normal control groups. Therefore, DAS is probably not due to a congenital or an acquired defect in Broca's motor speech area or adjacent brain area of the left hemisphere. The basis of this conclusion is discussed.