Chapter 11: Apraxia

Apraxia differentiates apraxia from other motor impairments like tremors, weakness, or ataxia and details a variety of testing methods including gesturing to command, imitation, and actual tool use. Key classifications discussed include limb-kinetic apraxia, which involves a loss of distal finger dexterity, and ideomotor apraxia, characterized by spatial and temporal errors such as using a body part as an object or failing to coordinate movement at the correct joints. The sources explore the underlying neuroanatomy, specifically focusing on the left hemisphere's dominance in storing "praxicons"—the mental representations or formulas of learned movements—primarily in the parietal cortex. Further insights are provided regarding the supplementary motor area’s role in translating these representations into motor programs and how callosal lesions can disconnect these areas, leading to unilateral deficits. The text also delves into conceptual apraxia, where the fundamental knowledge of tool-object associations or mechanical advantages is lost, and ideational apraxia, which disrupts the logical sequencing of complex multi-step tasks. Additionally, it addresses buccofacial apraxia affecting oral movements and the impact of neurodegenerative diseases such as Alzheimer’s and corticobasal degeneration. The chapter concludes by reviewing recovery processes and the importance of rehabilitative strategies focusing on functional restitution and compensatory skill-building for daily living.