Objective: To compare amyloid distribution in patients with Parkinson´s disease (PD) with visual hallucinations (VH-p) and without (VH-n).

Background: In patients with PD the prevalence of VH has been reported between 6 and 74%. Their content is really variable, and can range from passage and sense of presence to well-structured visual experiences. It has been shown that mild cognitive impairment in PD and VH, are both risk factors for dementia. In turn, PD-Dementia patients have amyloid-β deposits that have a synergic effect with α synuclein, responsible for dementia, but the role of amyloid-β deposits in VH-p remains unknown.

Method: Twenty-three non-demented PD patients (8 VH-p and 15 VH-n) underwent a neuropsychological, neurological examinations and 18F-Flutemetamol PET-MRI. They were classified as VH-p and VH-n using the MDS-UPDRS-I. Standardized uptake value ratio (SUVr) change was computed across 8 bilateral volumes of interest.

Results: Both groups showed no significant differences in clinical characteristics but their cognitive status differ, counting 6.7% of MCI in the VH-n group and 50% in the VH-p group. VH-p patients had an increased SUVr in right posterior cingulate (p=0.047) and right and left frontal regions (p= 0.047 and 0.013 respectively) compared to VH-n patients.

Conclusion: Patients VH-p seem to present a higher burden of amyloid-β in right posterior cingulate and frontal cortex. This observation could be related to the onset of VH in PD. Further studies with a higher number of patients should be done, to avoid the possible influence of MCI on the results.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/visual-hallucinations-in-parkinsons-disease-and-amyloid-burden-18f-flutemetamol-pet-mri-study/