Benarroch, Eduardo E.

Abstract Cognitive impairment is among the most common non-motor symptoms in parkinsonism and Parkinson’s disease, ranging from subjective complaints to dementia. Although several predictive factors have been described, their prognostic relevance remains uncertain. This study aims to examine the predictive association between clinical features and the risk of dementia and determine the incidence of dementia in a population-based cohort of incident parkinsonism cases. Patients with parkinsonism onset between 1991 and 2020 were identified using the Rochester Epidemiology Project records-linkage system. Subjects with cognitive impairment preceding motor symptoms onset or concomitant Alzheimer’s disease were excluded. Diagnoses of dementia and mild cognitive impairment were established using neuropsychological testing or brief cognitive screening. Development of dementia was assessed using a Cox proportional hazards regression model. Associations between dementia and each risk factor were individually estimated in adjusted Cox models. All risk factors were also included in a least absolute shrinkage and selection operator (LASSO) penalized multivariable Cox model. A total of 1,104 patients were included: 153 (13.9%) developed mild cognitive impairment and 543 (49.2%) developed dementia during follow-up. The cumulative incidence of dementia was 30.3% at 5 years, 48.6% at 10 years, 61.4% at 15 years, and 69.3% at 20 years, indicating that a considerable portion of patients remained free of dementia after a prolonged follow-up. The majority of patients with dementia were males (61.5%), and older age at disease onset was associated with risk of dementia (hazard ratio [HR] = 1.32, P < 0.001 per 5-year increment). In the penalized model, dementia risk was significantly higher among individuals presenting with impaired postural reflexes (HR = 1.26, P = 0.014), consistent with a poorer prognosis in akinetic-rigid-predominant parkinsonism. Eye movement abnormalities including reduced ocular range of motion (HR = 1.86, P < 0.001), and smooth pursuit alterations (HR = 1.34, P = 0.024) were also associated with dementia. Non-motor symptoms, including REM sleep behavior disorder (HR = 1.51, P < 0.001), orthostatic hypotension (HR = 1.30, P = 0.009), and constipation (HR = 1.24, P = 0.022), were linked to dementia risk, supporting a potential involvement of non-dopaminergic and central autonomic pathways in cognitive decline. These findings were largely confirmed in the Parkinson’s disease/Parkinson’s disease with dementia group, in which 77 (13.5%) developed mild cognitive impairment and 249 (43.5%) developed dementia. Among these patients, smooth pursuit alterations, reduced ocular range of motion, orthostatic hypotension, and constipation were associated with dementia.

Objective Dysautonomia affects many patients with Parkinson's disease and correlates with increased cardiovascular mortality. We describe the frequency and onset time of autonomic dysfunction relative to disease onset in early‐onset Parkinson's disease (EOPD) and explore its association with mortality. Methods We identified all incident Parkinson cases with motor‐symptom onset before age 50 years evaluated at the Mayo Clinic Health System (1990–2022) including sex‐ and age‐matched controls for each patient. Medical record review confirmed clinical diagnosis and assessed the presence and onset of autonomic symptoms, relative to Parkinson onset. Results We included 829 patients with EOPD and 829 healthy controls. The median age at disease onset was 42 years (interquartile range [IQR] = 37–46 years). Autonomic symptoms were present in 63.4% of patients, compared with 27.0% of unaffected controls, and proceeded motor symptoms in 91.4%. Forty‐seven percent of patients with early‐onset Parkinson's disease had constipation, 27.4% had bladder urgency, 19.3% had orthostatic intolerance, and 15.4% had sweat dysfunction. Among male patients, 36.8% had erectile dysfunction. In our EOPD population only, the presence of any autonomic‐impairment symptoms correlated with a 2.71‐fold increased mortality risk; each additional reported symptom increased the relative mortality risk by 50% ( p < 0.001). Patients with constipation or orthostatic intolerance had a 3.22‐ and 2.78‐fold higher mortality than patients without these symptoms. Interpretation Autonomic impairment affects 63.4% of patients with EOPD and carries a 3‐fold higher mortality risk, which increases with every additional autonomic symptom reported. In our cohort, autonomic symptoms appeared most commonly after motor onset, contrasting with prodromal autonomic impairment seen in late‐onset Parkinson's disease (LOPD). ANN NEUROL 2026;99:964–975