Objective: To identify the prevalence of amyloid positivity in patients with Parkinson’s disease (PD) without dementia in their eighties using CSF amyloid-beta 42 levels and compare it with patients in their sixties.

Background: Amyloid-beta plays a pivotal role in cognitive decline in PD. Aside from amyloid-beta, multiple proteinopathies (e.g., tau, α-synuclein, and TAR-DNA-binding protein 43) and vasculopathy have been implicated in the pathogenesis of cognitive impairment in Lewy body disease. However, in an era where anti-amyloid-beta antibodies have been implemented as disease-modifying therapies for Alzheimer’s disease, amyloid-beta remains a crucial protein of interest. The prevalence of amyloid positivity, evaluated using the cerebrospinal fluid (CSF) of patients with PD without dementia in their sixties, is lower than that in individuals with normal cognition without PD diagnosis in the same age range. However, it remains unclear whether this trend holds in patients with PD without dementia in their eighties.

Method: Eighty-nine patients with PD without dementia were retrospectively classified into two groups with a cut-off age of 73 years at diagnosis; a HIGH group and a LOW group, with mean age at diagnosis of 80.2 and 64.9 years, respectively. CSF samples were collected at diagnosis.

Results: Forty-nine and 40 patients were included in the HIGH group and LOW group, respectively. The prevalence of amyloid positivity in the HIGH group was 30.6%, which was significantly higher than that in the LOW group (10.0%) (p = 0.02). The prevalence of amyloid positivity in both groups was lower than that in participants with normal cognition in the same age range. This finding may be attributed to the shorter preclinical stage of asymptomatic cerebral Aβ deposition in PD, resulting from Aβ accelerating the transition from the asymptomatic to dementia stage.

Conclusion: The prevalence of amyloid positivity was 30.6% in the group with a mean age at diagnosis of 80.2 years, significantly higher than in the group with a mean age at diagnosis of 64.9 years. Our findings may encourage further studies to identify optimal disease-modifying therapies for PD patients without dementia in an aging society. This study was presented at AD/PD 2024 (March 6–7, 2024, Lisbon, Portugal).

« Back to 2025 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/age-related-trends-in-amyloid-positivity-in-parkinsons-disease-without-dementia/