Late developmental deficits in force control in children with hemiplegia.

Differences related to development were investigated using a finger isometric force task in children with cerebral palsy and control children. The increase in force and force control observed in controls did not take place in patients. In the younger subset of patients (< 10 years) the force produced by the non-affected hand was greater than in either hand of young controls. This effect was not observed in the older subset of patients (< 10 years). Older controls also differed from younger controls in that they used higher frequency feedback loops. In contrast, older patients failed to show this increase. Moreover, the failure occurred both in the affected and non-affected hand, indicating that abnormalities involve the force control system of both sides.