The visual regulation of goal-directed reaching movements in adults with Williams syndrome, Down syndrome, and other developmental delays.

Williams syndrome (WS) is a genetic disorder that causes general cognitive and developmental delays. Compared to persons with Down syndrome (DS) at the same developmental level, individuals with WS generally exhibit superior expressive language abilities, but have difficulty with tasks that require the visual control of movement. Recently it has been suggested that this latter problem reflects a deficit in dorsal stream function. In the present …