Impaired force coordination during object release in children with hemiplegic cerebral palsy

Recent studies on hand motor control in children with cerebral palsy (CP) h ave focused on the coordination of fingertip forces during the grasping and lifting of objects. However, little is known about the ability to replace and release an object from grasp, a function that is just as important for fine dexterity. The present study examines the coordination of fingertip fo rces during the replacement and release of an object (either 200 g or 400 g ) from grasp in 14 children (aged between 7 and 13 years) with hemiplegic C P and in 14 age-matched typically developing children. The results indicate that children with hemiplegic CP abruptly replaced the object but had a pr olonged and uncoordinated release of the grasp. Unlike what was seen in the control children, the grip and load forces decreased sequentially in the c hildren with CP. However, all the children could appropriately scale the ra te of force decrease based on somatosensory weight-related information from the ongoing lift. The results provide further information about the impair ed hand skills in children with hemiplegic CP.