Prevalence of Non-Motor Symptoms and Non-Motor Fluctuations in Parkinson's Disease Using the MDS-NMS

Non-motor symptoms (NMS) are frequent in Parkinson's disease (PD).

To estimate the prevalence of NMS and of non-motor fluctuations (NMF) using the Movement Disorders Society-Non-Motor Rating Scale (MDS-NMS) and other scales assessing NMS, and their relationship with sex and PD severity.

Cross-sectional study with a sample of 402 PD patients. The Hoehn and Yahr staging system (HY), Clinical Impression of Severity Index for PD (CISI-PD), MDS-NMS (including NMF- subscale), Non-Motor Symptoms scale (NMSS), and MDS-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) were applied. A NMS was considered present when scored ≥1. Differences in scores by sex and HY, CISI-PD, and MDS-UPDRS severity levels were calculated using Fisher's exact and chi-squared tests.

Using the MDS-NMS, NMS were present in 99.7% of patients and the mean number of NMS was 16.13 (SD: 9.36). The most prevalent NMS was muscle, joint or back pain (67.4% of the sample) and the least prevalent was dopamine dysregulation syndrome (2.2%). Feeling sad or depressed was significantly more prevalent in women. Using the MDS-NMS revealed more NMS than the other scales assessing NMS. NMF were present in 41% of the sample, with fatigue being the most prevalent symptom (68.5% patients with NMF), and no differences by sex. Patients with greater PD severity had higher prevalence of NMS than patients with lower severity.

Almost all patients with PD experience NMS, and many experience NMF. Prevalence rates for NMS using the MDS-NMS are higher than on other scales used and increase with higher disease severity.