Alzheimer's disease versus dementia with Lewy bodies: Cerebral metabolic distinction with autopsy confirmation

Seeking antemortem markers to distinguish Dementia with Lewy bodies (DLB) a nd Alzheimer's disease (AD), we examined brain glucose metabolism of DLB an d AD. Eleven DLB patients (7 Lewy body variant of AD [LBVAD] and 4 pure dif fuse Lewy body disease [DLBD]) who had antemortem position emission tomogra phy imaging and autopsy confirmation were compared to 10 autopsy-confirmed pure AD patients. In addition, 53 patients with clinically-diagnosed probab le AD, 13 of whom later fulfilled clinical diagnoses of DLB, were examined. Autopsy-confirmed AD and DLB patients showed significant metabolic reducti ons involving parietotemporal association, posterior cingulate, and frontal association cortices. Only DLB patients showed significant metabolic reduc tions in the occipital cortex, particularly in the primary visual cortex (L BVAD -23% and DLBD -29% vs AD -8%), which distinguished DLB versus AD with 90% sensitivity and 80% specificity. Multivariate analysis revealed that oc cipital metabolic changes in DLB were independent from those in the adjacen t parietotemporal cortices. Analysis of clinically diagnosed probable AD pa tients showed a significantly higher frequency of primary visual metabolic reduction among patients who fulfilled later clinical criteria for DLB. In these patients, occipital hypometabolism preceded some clinical features of DLB. Occipital hypometabolism is a potential antemortem marker to distingu ish DLB versus AD.