Disease progression in Parkinson's disease patients with subjective cognitive complaint

Little is known about the disease progression of Parkinson's disease patients with subjective cognitive complaint (PD-SCC). This longitudinal cohort study aims to compare the progression of clinical features and quality of life (QoL) in PD patients with normal cognition (NC), SCC, and mild cognitive impairment (MCI).

A total of 383 PD patients were enrolled, including 189 PD-NC patients, 59 PD-SCC patients, and 135 PD-MCI patients, with 1-7 years of follow-up. Linear mixed models were applied to evaluate longitudinal changes in motor symptoms, nonmotor features (cognitive impairment, depression, and excessive daytime sleepiness), and QoL in PD.

At baseline, PD-SCC patients had lower Beck Depression Inventory (BDI) scores and Parkinson's Disease Questionnaire-39 (PDQ-39) scores than PD-NC patients (all p < 0.05). Longitudinal analyses revealed that the PD-SCC group exhibited faster progression in terms of BDI scores (p = 0.042) and PDQ-39 scores (p = 0.035) than the PD-NC group. The PD-MCI group exhibited faster progression rates in the Epworth Sleepiness Scale scores (p = 0.001) and PDQ-39 scores (p = 0.005) than the PD-NC group. In addition, the PD-SCC group exhibited a greater reduction in attention (Trail Making Test Part A, p = 0.047) and executive function (Stroop Color-Word Test, p = 0.037) than the PD-NC group.

PD-SCC patients exhibited faster deterioration of depression and QoL than PD-NC patients, and SCC may be an indicator of initial attention and executive function decline in PD. Our findings provided a more accurate prognosis in PD-SCC patients.