Characterization of visuoconstructional disabilities in patients with probable dementia of Alzheimer's type.

The goal of this study was to systematically examine alterations underlying the graphical copying performance of Alzheimer's patients at different stages of cognitive decline, in light of a theoretical framework of visuoconstructional processing (Guérin, Ska, & Belleville, 1999). Eight patients with a diagnosis of probable Alzheimer's disease were studied. A group of 24 elderly subjects, of similar age to the patient group and slightly higher education, served as controls. The severity of the cognitive decline of each patient was measured with a standard neuropsychological battery. All subjects were administered a copying task and tasks measuring visual exploration, judgment of spatial relations and graphical planning. Group and individual results were analyzed. The group results suggested that visuoconstructional apraxia in patients with Alzheimer's type dementia is characterized by impaired visual exploration and judgment of spatial relations. Individual results revealed between-patient variability related to the severity of cognitive decline. Given the small number of patients, these observations need to be replicated with a larger-scaled study.