This study was designed to examine the patterns of apraxic disturbances and the relationships between action knowledge and other measures of semantic knowledge about objects in 10 well-characterized Alzheimer's disease (AD) patients. Five tasks were used to assess components of action knowledge (action–tool relationships, pantomime recognition, and sequential organization of action) and praxis execution (actual use, pantomiming) according to the cognitive model of praxis. Three tasks (verbal comprehension, naming, and a visual semantic matching task) were used to assess verbal–visual semantics. Considering patterns of apraxia first, conceptual apraxia was found in 9 out of the 10 AD patients, suggesting that it is a common feature even in the early stages of AD. Second, we found partly parallel deficits in tests of action-semantic and verbal–visual semantic knowledge in 9 AD patients. Impaired action knowledge was found only in patients with a semantic language deficit. These findings provide no evidence that “action semantics” may be separated from other semantic information. Our results support the view of a unitary semantic system, given that the representations of action-semantic and other semantic knowledge of objects are often simultaneously disrupted in AD. (JINS, 2000, 6, 693–703.)

Patients with probable Alzheimer's disease (AD) often have difficulties associated with semantic knowledge. Therefore, conceptual apraxia, a defect of action semantics and mechanical knowledge, may be an early sign of this disease. The Florida Action Recall Test (FLART), developed to assess conceptual apraxia, consists of 45 line drawings of objects or scenes. The subject must imagine the proper tool to apply to each pictured object or scene and then pantomime its use. Twelve participants with Alzheimer's disease (NINCDS–ADRDA criteria) and 21 age- and education-matched controls were tested. Nine Alzheimer's disease participants scored below a 2-standarddeviation cutoff on conceptual accuracy, and the three who scored above the cutoff were beyond a 2-standard-deviation cutoff on completion time. The FLART appears to be a sensitive measure of conceptual apraxia in the early stages of Alzheimer's disease. (JINS, 2000, 6, 265–270.)