Deficits in long-term retention of learned motor skills in patients with cortical or subcortical degeneration.

We investigated the acquisition and long-term retention of new skills in patients with cortical (Alzheimer's disease, AD) and subcortical (progressive supranuclear palsy, PSP; Parkinson's disease, PD) degeneration. The motor skill task performance of the PD and PSP patients improved with training, but the improvement disappeared within a few months, whereas AD patients retained learned skills for 3-18 months. The results of our experiments show that subcortical dysfunction induces a retention deficit for newly learned motor skills. Our present study suggests that a normal striatum is necessary for the formation of long-lasting motor skills, and that the striatum plays an important role as a motor skill consolidation system. Copyright 2004 Elsevier Ltd.