Prominent hypometabolism of the right temporoparietal and frontal cortex in two left-handed patients with primary progressive aphasia.

Primary progressive aphasia (PPA) is characterized by progressive deterioration of language function with relative preservation of other cognitive functions. Previous studies based on neuroimaging and histology point to predominantly left temporal pathology in PPA patients. Here we report two left-handed subjects with typical symptoms of the nonfluent form of PPA in whom 18F-FDG PET revealed an asymmetric right-hemispheric pattern of reduced glucose metabolism in the frontal and temporoparietal cortex. These findings support the hypothesis that PPA can be considered as a symptom complex rather than a disease entity.