Explicit and implicit motor learning in children with unilateral cerebral palsy

Objectives: The current study aimed to investigate the capacity for explicit and implicit learning in children with unilateral cerebral palsy. Participants: Children with left and right unilateral cerebral palsy and typically developing children shuffled disks toward a target. Design: A prism-adaptation design was implemented, consisting of pre-exposure, prism exposure, and post-exposure phases. Half of the participants were instructed about the function of the prism glasses, while the other half were not. Measures: For each trial, the distance between the target and the shuffled disk was determined. Explicit learning was indicated by the rate of adaptation during the prism exposure phase, whereas implicit learning was indicated by the magnitude of the negative after-effect at the start of the post-exposure phase. Results No significant effects were revealed between typically developing participants and participants with unilateral cerebral palsy. Comparison of participants with left and right unilateral cerebral palsy demonstrated that participants with right unilateral cerebral palsy had a significantly lower rate of adaptation than participants with left unilateral cerebral palsy, but only when no instructions were provided. The magnitude of the negative after-effects did not differ significantly between participants with right and left unilateral cerebral palsy. Conclusions: The capacity for explicit motor learning is reduced among individuals with right unilateral cerebral palsy when accumulation of declarative knowledge is unguided (i.e., discovery learning). In contrast, the capacity for implicit learning appears to remain intact among individuals with left as well as right unilateral cerebral palsy.