Cerebral metabolic dysfunction in patients with dementia with Lewy bodies and visual hallucinations.

AIMS To identify the pattern of cerebral hypometabolism in patients with dementia with Lewy bodies (DLB) and visual hallucinations (VH). METHODS Fourteen patients with DLB and VH, 7 with DLB without VH and 16 healthy controls underwent clinical and (18)F-FDG PET evaluations. The 2 patient groups did not significantly differ in their clinical characteristics, except in the occurrence of VH. A voxel-wise comparison of (18)F-FDG PET scans was conducted between each of the 2 patient groups and the control group, and the patient groups among each other. RESULTS Compared with the control group, hypometabolic regions were more extensive and confluent in the patient group with VH than in the group without VH. The direct comparison between the 2 patient groups revealed a significant metabolic deficit in the group with VH at the right occipito-temporal junction and the right middle frontal gyrus. CONCLUSIONS These results suggest that hypometabolism in visual association areas rather than the primary visual cortex is involved in VH in DLB.