Visual guidance during an interception task in children with Spastic Hemiparetic Cerebral Palsy.

The aims of the study are to determine the presence of adjustments in walking behaviour of children with Spastic Hemiparetic Cerebral Palsy (SHCP) during the interception of a moving ball and, whether the angle between the ball and the participant is kept constant. This would support the use of the so-called bearing angle (BA) strategy in interception of the object. Children with left hemisphere damage intercepted a ball from a conveyor belt at three different velocities, from a frontal or lateral orientation and with their impaired or less-impaired hand. The participants walked from a distance of 4m perpendicularly to the belt. Children seemed to have less successful trials when grasping with the impaired hand. The results showed that the walking velocity was adjusted to the ball velocity. When they grasped with the impaired hand, children initially moved faster to the interception point, while closer to the belt significant slower. The BA showed less variation over the trajectory when the children grasped with their less-impaired hand or when the ball velocity increased. It was concluded that children with SHCP were able to take their impairment into account as indicated by adjustments in walking behaviour. However, these adjustments in walking velocity were not sufficient to compensate totally for the limited reaching ability in the impaired hand. As a result of these adjustments, the amount of variation from the constant BA seemed to deviate more from typically developing children when grasping with impaired hand than when grasping with less-impaired hand.