Posterior cortical atrophy variants of Alzheimer's disease.

Posterior cortical atrophy (PCA) was first described by Benson in 1988 and, since then, has been regarded as a variant of Alzheimer's disease. We present 2 patients with symptoms suggestive of PCA and 2 patients with apraxia as the initial manifestation. Primary motor and sensory modalities were intact. Mild memory impairment was present early in the course of the disease and gradually worsened. Parieto-occipital atrophy was evident on brain MRI. HMPAO-SPECT demonstrated parieto-occipital hypoperfusion significantly different from the temporoparietal hypoperfusion usually described in senile dementia of the Alzheimer type. These findings suggest that HMPAO-SPECT can help in diagnosing atypical variants of Alzheimer's disease. We suggest that PCA represents two clinically related behavioral phenotypes: PCA with predominantly apraxia manifestations and PCA with predominantly visuospatial disturbances. Copyrightz1999S.KargerAG,Basel