Non‐motor symptoms burden in treated and untreated early Parkinson's disease patients: argument for non‐motor subtypes

Background and purpose Non‐motor symptoms ( NMS s) occurring at an early stage of Parkinson's disease ( PD ) may impair quality of life more than motor symptoms. This study aimed to evaluate the severity of overall NMS profile and burden of NMS s in early PD patients, treated (time since confirmed diagnosis of 5 years or less) or drug naive ( DN ). Methods Cross‐sectional data from an ongoing multicentre study (16 sites) were obtained and specifically an NMS data set from validated scales was analysed in treated and DN PD patients. Results A full data set was available in 234 unique early PD patients. Of them, there were 170 treated (63.5% males, mean age 68.2 years) and 64 DN patients (64.1% males, mean age 66.5 years). Compared to DN patients the time since confirmed diagnosis was significantly longer in treated PD patients (1.9 years vs. 3.7 years, P  < 0.001). Fatigue (57.7%), urinary urgency (57.1%), nocturia (55.3%), memory difficulties (51.2%) and urinary frequency (48.8%) were the most prevalent NMS s amongst treated PD , whereas DN PD reported most frequently sadness (57.8%), fatigue (57.8%), lightheadedness (53.1%), memory difficulties (48.4%) and urinary urgency (46.9%). Conclusions Our results suggest that NMS s are dominant in the untreated and early phase of PD causing a considerable burden. This warrants investigation of the issue of NMS subtyping within PD .