Parkinson's disease patients with pain suffer from more severe non-motor symptoms

Non-motor symptoms, including pain, depression, sleep disorder, and olfactory dysfunction, occur frequently in patients with Parkinson's disease (PD), even before the onset of motor symptoms. Although studies have examined the correlation between pain and depression or sleep disorder in PD, few studies have investigated the correlation between pain and a range of other non-motor symptoms of PD. PD patients (n = 142) with or without pain were included in the study. PD severity was evaluated with the Unified Parkinson's Disease Rating Scale (UPDRS) and the Hoehn and Yahr (H/Y) staging scale. Pain severity was analyzed with the Visual Analog Scale. The Hamilton Rating Scale for Depression (HRSD; 24 items), Montreal Cognitive Assessment Beijing Version (MoCA), and non-motor questionnaire (NMSQT) measured symptoms of depression, cognitive function, and non-motor symptoms. The incidence of pain was 47.9 % in patients with PD, most of whom had moderate pain levels. Patients with pain showed higher HRSD, UPDRS, H/Y, and NMSQT scores and lower MoCA scores compared to those of patients without pain. HRSD and NMSQT scores were closely related with pain (P < 0.001). Non-motor symptoms were more prominent in patients with pain compared to that of controls and PD patients without pain.