Apraxia and motor-skill acquisition in Alzheimer's disease are dissociable

Many patients with Alzheimer's disease (AD) are apraxic and the apraxia has been posited to be related to a loss of movement representations. Whereas patients with Alzheimer's disease have been reported to demonstrate normal motor learning on a rotor pursuit skill acquisition task, it is unknown whe ther AD subjects who are apraxic demonstrate normal skill-learning. We test ed subjects with probable AD and normal controls on a rotor pursuit task. W e also tested the AD subjects for ideomotor apraxia. Subjects with AD who w ere apraxic had normal motor learning. In addition, praxis score did not co rrelate with performance on the skill-acquisition task. The results suggest that ideomotor praxis and motor learning are at least partly dissociable. (C) 1999 Elsevier Science Ltd. All rights reserved.