Cerebral Metabolic Dysfunction in Patients with Dementia with Lewy Bodies and Visual Hallucinations

Abstract

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 ¹⁸F-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 ¹⁸F-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.

18F-FDG PET in Posterior Cortical Atrophy and Dementia with Lewy Bodies

“…One could hypothesize that dysfunction in this network of structures may contribute to the overlapping features observed across PCA and DLB. Occipital hypometabolism has been associated with the presence of DLB clinical features (27)(28)(29), and visual hallucinations, parkinsonism, and RBD were observed in some of our PCA patients, as has previously been reported (13). Atrophy of the primary visual cortex and thalamus has indeed been associated with the presence of visual hallucinations in PCA (13), and parietal and thalamic atrophy has been associated with parkinsonism in PCA (30).…”

Neuroimaging Findings in Dementia with Lewy Body: A Review

“…In the context of DLB, previous FDG-PET studies revealed a pattern of hypometabolism in the medial occipital cortex (Klein et al, 2010;Perneczky et al, 2008a;Satoh et al, 2010), in agreement with the previously reported SPECT data of hypoperfusion. Furthermore, other literature data found a correlation between cerebral hypometabolism in right temporoparietal cortex, prefrontal cortex and the precuneus and patients' performance level of everyday competence (Perneczky et al, 2008b;Perneczky et al, 2009a).…”

Dementia with Lewy bodies

“…11,13,26 Occipital hypometabolism also differentiates clinical and autopsy-proven DLB from AD cases. 13,26,27 In DLB, occipital hypometabolism correlates with visual hallucinations 28 and improves with acetylcholinesterase inhibitor treatment. 29 The occipital hypometabolism in DLB is independent of Ab load 11 and is thought to be related to impaired cholinergic transmission or synaptic dysfunction associated with a-synuclein.…”