Cerebral glucose metabolism in Wernicke's, Broca's, and conduction aphasia.

Cerebral glucose metabolism was evaluated in patients with either Wernicke's (N = 7), Broca's (N = 11), or conduction (N = 10) aphasia using 18F-2-fluoro-2-deoxy-D-glucose with positron emission tomography. The three aphasic syndromes differed in the degree of left-to-right frontal metabolic asymmetry, with Broca's aphasia showing severe asymmetry and Wernicke's aphasia mild-to-moderate metabolic asymmetry, while patients with conduction aphasia were metabolically symmetric. On the other hand, the three syndromes showed the same degree of metabolic decline in the left temporal region. The parietal region appeared to separate conduction aphasia from both Broca's and Wernicke's aphasias. Common aphasic features in the three syndromes appear to be due to common changes in the temporal region, while unique features were associated with frontal and parietal metabolic differences.