Fronto-parietal and cerebellar contributions to motor dysfunction in Williams syndrome: A review and future directions

Williams syndrome (WS) is a rare genetically based neurodevelopmental disorder which is associated with mental retardation and a distinctive cognitive and behavioural profile, including weaknesses in visuospatial processing but preserved language abilities and face recognition. Relative to the cognitive characteristics of WS, there is a dearth of research into the movement problems associated with this syndrome. This is despite the evidence from clinical and experimental studies that indicate disordered movement may be an important neuromotor characteristic of WS. This article reviews the current neuroanatomical and behavioural literature on visuomotor deficits in WS, and examines the differential role of fronto-parietal and cerebellar regions in motor dysfunction. The role of these brain regions in disturbances of visuomotor control is discussed in the context of the important interaction with attention, executive and planning deficits in WS. Finally, directions are provided for future research emphasising the need to examine developmental changes in motor functioning across a range of movement parameters and to investigate the functional correlates of abnormal neural connectivity in WS. It is concluded that further investigation of motor dysfunction in WS may provide us with a greater understanding of how important movement-related brain regions develop and operate. (c) 2007 Elsevier Ltd. All rights reserved.