Continuous inter-limb coordination deficits in children with unilateral spastic cerebral palsy

Background: Continuous inter-limb coordination and the ability to offset perturbations to a movement pattern (i. e., stability) are important factors in efficient motor performance. Patients with movement disorders often show deficits in coordination and stability, although little is known about these features in children with cerebral palsy. The purpose of this study was to identify the continuous inter-limb coordination and stability deficits in children with cerebral palsy and determine if improvement occurs with upper extremity intervention. Methods: Children with cerebral palsy participated in bimanual or unimanual intensive therapy. Continuous inter-limb coordination between the arms and between the more-affected arm and leg was evaluated using relative phase analysis during four gross motor tasks, including in-place marching and standing with asymmetric and symmetric arm swing. A control group of children with cerebral palsy and a group of typically developing children were also evaluated. Findings: Children with cerebral palsy displayed coordination deficits compared to typically developing children (p<0.01), yet both groups presented similarly poor levels of stability (p=0.39). Compared to standing, adding legs to the task negatively impacted the coordination (p<0.01) and stability (p<0.01) of all children. Both groups improved coordination between the arms post-intervention (p>0.05 for all cases), however neither group improved stability (p < 0.05 for all cases). Interpretation: Relative phase analysis successfully provided a sensitive measurement of coordination and stability in pathologic and non-pathologic populations. Findings indicate that all children have difficulty producing consistent movement patterns and suggest that both bimanual and unimanual interventions can improve continuous coordination in children with cerebral palsy.