Reversal of handedness effects on bimanual coordination in adults with Down syndrome

Background Research on unimanual tasks suggested that motor asymmetries between hands may be reduced in people with Down syndrome. Our study examined handedness (as assessed by hand performance) and perceptual-motor integration effects on bimanual coordination. Methods Adults with Down syndrome (13 non-right-handed, 22 right-handed), along with comparison groups of adults (16 non-right-handed, 21 right-handed) and children (15 non-right-handed, 22 right-handed) without Down syndrome, drummed with auditory, verbal and visual instructions. Results In contrast to handedness effects in the children and adults without Down syndrome, right-handed participants with Down syndrome led more with the left hand, and had lower coordination stability than non-right-handed participants with Down syndrome. Conclusions The reversed handedness effect during bimanual coordination suggests a complex relationship between handedness and task requirements in adults with Down syndrome.