Background: Dysphagia significantly impacts prognosis in individuals with multiple system atrophy (MSA). While video-based assessments are practical, their limited availability highlights the need for a simple tool such as the Dysphagia Severity Scale (DSS) in clinical practice.

Objectives: To evaluate the utility of the DSS in assessing dysphagia in MSA patients and its correlations with clinical indices.

Methods: We examined 43 MSA patients using the DSS and other clinical measures, including the Unified MSA Rating Scale (UMSARS) and cerebrospinal fluid 5-hydroxyindoleacetic acid levels. As a follow-up, 11 of 43 patients underwent a secondary DSS evaluation. Spearman's correlation and linear mixed models were used to analyze cross-sectional and longitudinal relationships.

Results: DSS scores were significantly correlated with UMSARS Parts 1, 2, and 4, as well as disease duration and blood pressure changes. This indicates that the DSS is sensitive to MSA-related motor and autonomic dysfunctions, and that the DSS could provide a more detailed assessment of swallowing function compared with the UMSARS Part 1 swallowing subscore. Additionally, DSS score was correlated with cerebrospinal fluid 5-hydroxyindoleacetic acid levels. Our longitudinal analysis further supported the role of DSS score as a reliable marker of dysphagia progression over time.

Conclusions: The DSS is a sensitive and practical tool for evaluating dysphagia. Thus, combining the DSS and UMSARS could improve dysphagia monitoring in individuals with MSA. Our data support the use of the DSS as a valuable clinical and research tool in MSA management.

Keywords: 5‐hydroxyindoleacetic acid; disease severity; dysphagia severity scale; multiple system atrophy; serotonergic neurons.

© 2025 The Author(s). Movement Disorders Clinical Practice published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.