11 - Limb Apraxias and Related Disorders

Abstract

Apraxia is an inability to correctly perform learned skilled movements. Apraxia is essentially a cognitive deficit in motor programming and results in errors either of the spatiotemporal processing of the movements or in the content of the actions. In limb apraxia, there is an inability to correctly execute these movements in an arm or hand owing to neurological dysfunction. Limb apraxia is a salient sign in patients with strokes, Alzheimer disease, corticobasal syndrome, and other conditions. A historical perspective provides insight into the classification and localization of limb apraxias. The model of left parietal movement formulas and disconnection syndromes introduced by Liepmann over 100 years ago continues to be a compelling model today. In the context of a dedicated apraxia examination and analysis for spatiotemporal or content errors, several types of limb apraxias are classified. The focus of this chapter is on the seven major limb apraxias of the upper extremities. They include ideomotor apraxia, parietal variant; ideomotor apraxia, disconnection variant; dissociation apraxia; ideational apraxia; and conceptual apraxia. Also included is limb-kinetic apraxia, a disorder that some argue is not a true apraxia, but instead a more basic disturbance in fine motor movements. Other movement disorders may be more distantly related or confused with the limb apraxias. Overall rehabilitation strategies can be helpful interventions for the disturbances in limb apraxias. Our understanding and management of limb apraxias continues to advance with recent advances in technology and rehabilitation.