Cognitive Changes in Early Untreated Parkinson's Disease
Abstract
Cognitive impairment is the most common non-motor symptom in Parkinson’s disease (PD), affecting up to one-third of early-stage patients. However, the cognitive profile in early PD remains unclear due to the use of heterogenous samples of disease severity, small sample sizes, and the inclusion of medication effects. This study aims to characterize cognitive deficits in early PD using a large, drug-naive sample. This study examined performance on the Montreal Cognitive Assessment and the Hopkins Verbal Learning Test from the Parkinson’s Progression Markers Initiative dataset (n= 643 patients with PD; n= 240 healthy controls). Patients were restricted to ≤ 12 months of disease duration and had not begun chronic dopaminergic therapy. Bayesian analyses of covariance showed Group effects in global cognition, executive function, recall, and retrieval between PD patients and controls. This suggests that early PD patients exhibit multidomain cognitive deficits, including global cognition, executive function, and memory.