Inferior Parietal Region Implicated in Neurocognitive Impairment in Schizophrenia

To the Editor.—  Berman et al,¹ in the July 1988 issue of the Archives, demonstrated increased cerebral blood flow in posterior cortical regions of both schizophrenic subjects and control subjects while they were performing the Raven's Progressive Matrices task. Cerebral blood flow in the two groups did not differ significantly. In contrast, schizophrenics' failure to activate the dorsolateral prefrontal cortex while doing the Wisconsin Card Sort Test² has now been replicated.³These authors argued that the data support their contention that there is both brain-regional and behavioral specificity in schizophrenia. We suggest that a specific region within the parietal cortex is also related to neurocognitive deficit in schizophrenia.We have recently examined the relationship of scores from a neuropsychological test battery with regional brain fludeoxyglucose F 18 measured by positron emission tomography. The procedures were administered within 1 week of each other. We examined 16 drug-free patients