Abnormal adaptation in children affected by cerebral palsy to robot generated dynamic environment

This paper aims to investigate how robotic devices can be used to understand the mechanism of sensorimotor adaptation in pediatric subjects affected by hemiparetic cerebral palsy. Previous studies showed how healthy adults, after training in presence of a systematic structured disturbing force field, show an "after effect" and therefore they highly adapt and compensate the external disturbance. An open issue is whether this adaptive capability is preserved or disrupted in pediatric impaired subjects when they experience a robot generated dynamic environment. Fourteen pediatric Cerebral Palsy subjects (CP group), and age-matched control group were exposed to a robot generated speed-dependant force field; during familiarization (no forces generated by the robot) the movement of the CP subjects were more curved, displaying greater and variable directional error; in the force field phase both the groups showed an after-effect, but the CP group had a non significant adaptation rate. This outcome suggests the CP subjects have reduced ability to learn external force and they make greater aiming error because of an inefficient anticipatory strategy during visuomotor task.