Longitudinal evolution of motor and non-motor symptoms in early-stage multiple system atrophy: a 2-year prospective cohort study

Background The progression of motor and non-motor symptoms (NMS) and the sensitivity of each item of the Unified Multiple System Atrophy Rating Scale (UMSARS) to change remain unclear in Chinese patients with early-stage multiple system atrophy (MSA). We investigated the evolution of motor symptoms and NMS in early-stage MSA and the sensitivity of each item included in the UMSARS to change over a 2-year follow-up. Methods Motor symptoms and NMS were recorded at baseline and at 1- and 2-year follow-ups based on the UMSARS and the NMS scale. Generalized estimating equation models were used. The sensitivity of an item included in the UMSARS to change was assessed by calculating a standardized effect using the mean annual change divided by the standard deviation of the change. Results We enrolled 246 consecutive patients with MSA and 97 MSA completed the 2-year follow-up. The mean total UMSARS score increased by 11.90 and 22.54 points at the 1- and 2-year follow-ups, respectively. UMSARS-I items associated with motor functions were more sensitive to change and those associated with autonomic dysfunction showed less sensitivity to change. Items 4 (tremor at rest), 5 (action tremor), and 3 (ocular motor dysfunction) of the UMSARS-II were less sensitive to change. The prevalence and severity of NMS significantly increased over the 2-year follow-up. Conclusions We observed significant progression in motor symptoms and NMS in patients with early-stage MSA. Our results provide useful information to support the revision of the UMSARS.

Automated summary

The study investigated the progression of motor and non-motor symptoms in early-stage MSA patients over a two-year period. It found that items related to motor functions in the UMSARS were more sensitive to change, while those associated with autonomic dysfunction showed less sensitivity. The prevalence and severity of NMS significantly increased over the 2-year follow-up.