Apraxia in Alzheimer's disease.

We studied apraxia in 28 patients with senile dementia of the Alzheimer type (SDAT). Although SDAT patients were impaired compared with age-matched controls on tests of ideomotor and ideational apraxia, not all types of movements were affected to the same degree. Limb transitive movements were especially vulnerable, while limb intransitive, buccofacial, and axial movements were relatively spared. When pantomiming limb transitive movements, SDAT patients made frequent body part as object and spatial errors. There was no significant difference between performance on verbal command and imitation, but there was considerable improvement with the use of actual objects. Disorders of skilled movement in SDAT were qualitatively similar to the apraxic syndromes following left parietal damage. Apraxia in SDAT suggests posterior left hemisphere cortical involvement and may be apparent even in patients with good language functions.