Topographic patterns of brain functional impairment progression according to clinical severity staging in 116 Alzheimer disease patients: FDG-PET study.

The study aimed to explore topographic progression pattern of brain functional impairment according to clinical stage in Alzheimer disease (AD). One hundred and sixteen AD patients and 25 normal subjects underwent a [18F] fluorodeoxyglucose-positron emission tomography scan. Regional cerebral glucose metabolism was compared between severity groups based on the Clinical Dementia Rating through voxel-based analyses. As clinical severity progressed, hypometabolic areas gradually increased, involving initially posterior cingulate cortex, later temporoparietal, and finally frontal and some subcortical areas. The results indicate that progression patterns of hypometabolism in AD are close to that of typical neuropathology, but that they do not fully coincide with it.