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 pres ent 2 patients with symptoms suggestive of PCA and 2 patients with apraxia as the initial manifestation. Primary motor and sensory modalities were int act. 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 dif ferent from the temporoparietal hypoperfusion usually described in senile d ementia of the Alzheimer type. These findings suggest that HMPAO-SPECT can help in diagnosing atypical variants of Alzheimer's disease. We suggest tha t PCA represents two clinically related behavioral phenotypes: PCA with pre dominantly apraxia manifestations and PCA with predominantly visuospatial d isturbances. Copyright (C) 1999 S. Karger AG, Basel.