Cognitive-driven ADL Impairment as a Predictor for PDD

Mild cognitive impairment in Parkinson's disease (PD-MCI) is the highest risk factor for Parkinson's disease dementia (PDD). The core feature for differentiating PDD from PD-MCI is the loss of the ability to perform activities of daily living (ADL). As Parkinson's Disease (PD) is primarily a movement disorder, the distinction between motor and cognitive contributions to ADL in PD is an obvious challenge, which the investigators aimed to explore in this study. The goal of the study is to evaluate whether PD-MCI patients with more pronounced, cognitive-driven ADL impairment are at higher risk for cognitive worsening and PDD. A longitudinal follow-up assessment of 262 non-demented PD patients will be conducted over the next two years, with a comprehensive clinical assessment as well as biomarker sampling (cerebrospinal fluid and blood markers). Primary longitudinal outcome will be conversion to PDD and PD-MCI. Conversion rates of patients with and without additional mild cognitive-driven ADL impairment at baseline will be compared. Novel scores of the Pfeffer Functional Activities Questionnaire (FAQ) are used to assess instrumental ADL, differentiating between cognitive- and motor-driven ADL impairment in PD-MCI.