Manual asymmetries in the performance of sequential movement by adolescents and adults with Down syndrome.

Movement-sequencing deficits and possible manual-performance asymmetries in right-handed adolescents and adults with Down syndrome were examined. In Experiment 1, subjects with Down syndrome and retarded and nonretarded control subjects finger-tapped with both hands. Although both retarded groups finger-tapped more slowly than did nonretarded subjects, the two retarded groups did not differ. Subjects with Down syndrome, however, failed to show …