Fingertip forces during object manipulation in children with hemiplegic cerebral palsy. I: Anticipatory scaling

Previous studies of grasping and object manipulation in children with cereb ral palsy (CP) have suggested a dichotomy in the ability to use anticipator y control (planning) of the fingertip force output, depending on the type o f sensory information (tactile or proprioceptive) on which it is based. The present study further explores this issue by testing the ability of 15 chi ldren with hemiplegic CP aged between 8 and 14 years to scale the fingertip force output in advance during the lifting of small objects whose weight a nd surface texture are varied. The results indicate that children with hemi plegia can use anticipatory control based on both the weight and texture of the object, but require a greater number of trials than age-matched childr en without CP (control children) before they call do so. We suggest that th e initial lack of anticipatory control results from an indistinct internal representation of the object's physical properties due to disturbed sensory mechanisms, which may have direct implications for therapeutic interventio n.