Fingertip force planning during grasp is disrupted by impaired sensorimotor integration in children with hemiplegic cerebral palsy.

In the present study we examine the ability of children with hemiplegic cerebral palsy (CP) to use anticipatory control of fingertip forces during grasping, and whether anticipatory control is facilitated by lifts with the contralateral hand. Eight children with CP (age 4-13) were asked to perform several lifts of either a 250-g or 500-g object instrumented with force transducers with one hand, followed immediately by several lifts with the contralateral hand. This was repeated for each combination of weight and starting (involved or non-involved) hand. Similar to previous studies, the rate of load force development showed impaired anticipatory control during lifts with the involved hand, intact anticipatory control in the non-involved hand, and transfer of anticipatory control from the non-involved to the involved hand. Surprisingly, however, we also found a transfer from the involved hand to the non-involved hand. The results suggest that the impaired anticipatory control in the involved hand is not purely a sensory or motor problem, and instead is due to an inability to appropriately integrate sensory information with subsequent motor output of the same hand. These results provide important information about the mechanisms underlying impaired anticipatory control, and may have important clinical implications.