Visuospatial deficits with preserved reading ability in a patient with posterior cortical atrophy.

Visuospatial deficits are characteristic of posterior cortical atrophy (PCA). A 58 year old woman had progressive dressing apraxia and environmental disorientation but continued to read voraciously. Positron emission tomography revealed hypometabolism of the occipitoparietal regions bilaterally, consistent with PCA. The symptoms suggested predominant dysfunction of the dorsal ("where") stream with abnormalities in visual localization and visuospatial integration; however, the patient also had a less pronounced apperceptive object agnosia. Further analysis of her preserved reading ability was performed. Familiar irregular words were read rapidly, but nonsense words were read slowly in a letter-by-letter fashion. She had a word superiority effect for embedded words and words with obscured letters but had difficulty reading stylized script or printing in unusual fonts. These findings suggested a dissociation between reading routes. Although the patient had a phonological dyslexia, her visuospatial processing was sufficient for access to preserved visual word forms for efficient lexical reading.