Objective: To estimate the prevalence of cognitive impairment in a diverse Parkinson’s disease (PD) cohort and explore its associations with vascular, motor, and non-motor determinants.
Background: Cognitive impairment in PD is well recognized, but its prevalence and associated clinical factors in multiethnic clinical cohorts remain insufficiently characterized.
Method: The East London Parkinson’s disease project is a cross-sectional, multi-ethnic, single tertiary-center study at the Royal London Hospital. This was a substudy of patients with PD recruited between July 2022 and July 2025. Among 237 recruited patients whose cognitive status was defined by expert consensus, 223 were included in the analysis after excluding those with atypical or secondary parkinsonism, other dementias, or study withdrawal. Exposures were vascular risk factors and motor and non-motor clinical features. The main outcome was PD cognitive impairment (PDCI), defined as PD mild cognitive impairment (PDMCI) or PD dementia (PDD) by expert clinical consensus using clinical assessment, cognitive screening, and imaging data.
Results: Patients with PDCI were older than those with normal cognition (median [IQR], 74.0 [12.2] vs 66.0 [15.0] years). The prevalence of PDCI was 50.2% (112); 27.8% (62) with PDD, and 22.4% (50) with PDMCI. In adjusted analyses, South Asian ethnicity was associated with higher odds of PDCI (OR, 3.60, 95% CI, 1.68-7.69; p<.001) after adjustment for age, sex, years of education, disease duration, and depression scores. Smoking was associated with higher odds of PDCI (OR, 3.62, 95% CI, 1.56-8.41; p=0.003) in the adjusted model. Higher motor severity (Movement Disorders Society Unified Parkinson’s Disease Rating Scale Part III: OR per point increase, 1.07, 95% CI, 1.04-1.10; p<0.001), and daytime somnolence score (Epworth: OR per point increase, 1.08, 95% CI, 1.01-1.16; p=0.027) were also associated with higher odds of PDCI.
Conclusion: In this multiethnic PD cohort, cognitive impairment was common, and South Asian ethnicity was associated with higher odds of impairment. Smoking, greater motor severity, and higher daytime somnolence were also associated with higher odds of cognitive impairment.
To cite this abstract in AMA style:
A. Zirra, K. Dey, E. Camboe, E. Bhadra, R. Laban, B. Huxford, S. Hussain-Ali, C. Simonet, C. Budu, D. Gallagher, S. Waters, V. Azoidou, T. Boyle, A. Lees, M. Perinan, C. Marshall, A. Noyce. Prevalence and Clinical Determinants of Cognitive Impairment in a Diverse Parkinson’s Disease Cohort [abstract]. Mov Disord. 2026; 41 (suppl 1). https://www.mdsabstracts.org/abstract/prevalence-and-clinical-determinants-of-cognitive-impairment-in-a-diverse-parkinsons-disease-cohort/. Accessed October 1, 2026.« Back to 2026 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/prevalence-and-clinical-determinants-of-cognitive-impairment-in-a-diverse-parkinsons-disease-cohort/