Cognitive and motor processing in mild spastic cerebral palsy: an event-related potential study

Cerebral palsy (CP) is a motor disorder often accompanied by cognitive deficits. The spastic subtype is the most common subtype (66 % - 82 %), and abnormalities in attention, working memory, and executive functions are common clinical observations in this group. The present series of event-related potential (ERP) studies investigated cognitive and motor processing in youth with mild spastic cerebral palsy. Attention, working memory, and executive functions were evaluated in an oddball task and in a memory search task. In a series of four studies, it was found that fundamental attention processes were intact in youth with mild spastic cerebral palsy when measured in a condition requiring no overt reactions (Study I). Also stimulus evaluation processing, event preparation and action planning were intact in the group of patients, suggesting that patients’ motor slowness reflected poor motor execution processes (Study II). Moreover, error responses in youth with mild spastic cerebral palsy were associated with weak motor preparation, but patients were detecting their errors and improved their performance in next trial (Study III). Finally, we found that error making was foreshadowed by a decrease in stimulus evaluation in the patient group and in the control group. Further, altered motor preparation for erroneous responses discovered in study III was perceived already in the correct trial directly preceding an error in the patient group. (Study IV). It was concluded that although the patient group showed intact stimulus and response evaluation capacity, their compromised behavioral outcomes reflected difficulties in motor execution processes and fluctuations in motor presetting.