Learning impairment of time-constrained skillful movements in parkinson's disease

Daily activity is largely based on self-paced, sequential and highly practiced motor acts. These kinds of movements seem to be those selectively impaired in parkinsonian patients (PP). An interesting procedure to explore the way in which successive events are properly timed during preparation for such motor sequences is by the use of a time-constrained paradigm.This approach can provide insight into how a person learns, stores, plans and carries out actions. The control of timing is an explicit constraint of the Skilled Perceptual Task (SPT). since timing directly affects performance. By this paradigm it is possible to detect electrophysiological signals related to preprogramming during the acquisition of an internally-triggered motor skill. We found in a group of 11 PP (59 74 + 12.53) off-therapy, a significant progressive increase, on Cz. of the amplitude of the slow negative potential (BP) related to the preprogramming activity. A different electrophysiological trend was observed in age-matched control subjects. Our data showed in PP an impairment of the progressive acquisition of a correct timing control of self-paced sequences, that is. a defective learning of a time-constrained motor skill.