[The clinical syndrome of posterior cortical atrophy].

Posterior cortical atrophy (PCA) is a syndrome that involves distinct neuropsychological deficits. This paper presents the clinical and neuropsychological findings recorded in four patients with PCA and reviews the characteristics of the syndrome and other conditions that need to be considered in the differential diagnosis. The cardinal symptoms of PCA are deficits of higher visual and spatial functions (mostly taking the form of Balint's syndrome), variably associated with disorders of visual perception, topographical disorientation, visual object agnosia and prosopagnosia, and deficits affecting reading, copying, drawing, and calculation. PCA is mostly associated with histopathological changes similar to those found in dementia of Alzheimer type (DAT), which are located predominantly in posterior brain regions. Memory and language functions tend to be preserved better and for a longer time in PCA than in the normal variant of DAT. SPECT and PET show deficits of perfusion and metabolism in both parietal and occipital lobes. The diagnosis of PCA is based on neuropsychological and imaging findings.