Impairment severity selectively affects the control of proximal and distal components of reaching movements in children with hemiplegic cerebral palsy

This study explored proximal-to-distal components during goal-directed reaching movements in children with mild or moderate hemiplegic cerebral palsy (HCP); [seven females, four males; mean age 8y 6mo; SD 27mo], compared with age-matched, typically developing children (seven females, five males; mean age 8y 3mo [SD 25mo]. Severity of HCP was assessed following the approach of Claeys et al. Optoelectronic registrations were made during unimanual reaching-to-grasp and reaching-to-hit movements with both the affected/non-preferred and unaffected/preferred side. Regardless of task, the children with HCP, particularly those with moderate impairment, displayed less optimal spatiotemporal organization of movements performed with the affected arm. Compared with the goal to hit, and increasingly with more severe impairment, children with HCP adapted to the goal to grasp by recruiting augmented shoulder movements when reaching with the affected side. A resulting impact on distal kinematics was found in shorter, straighter, and less segmented movement paths. Thus, depending on severity of hemispheric lesions and task complexity, unilateral brain injuries in HCP may selectively affect neural pathways underlying both proximal and distal arm movement control. Levels of both ipsi- and contralateral activation in relation to side and lesion severity should be considered in future studies on prehension movements in HCP.