Prevalence and Clinical Types of Tremor in Multiple Sclerosis and its Associated Disability: A Systematic Review

OBJECTIVE: To describe the state of literature regarding prevalence, clinical types of tremor in Multiple Sclerosis and associated disability. BACKGROUND: Tremor has long been recognized as an important symptom of multiple sclerosis. This can be intention and postural tremor that affects the upper limbs. Patients with multiple sclerosis who experience tremor of any severity typically retire early or lose their jobs due to disability. METHODS: This systematic review was performed up to September 9, 2022. Article selection was performed by searching the MEDLINE (PubMed) and EMBASE electronic bibliographic databases. The search strategy was not limited by study design but only for articles in the English language. RESULTS: A total of nine full-text articles were included in the analysis. Six studies were cross-sectional studies; one each was a prospective observational study, a case-control study, a community-based cohort. The prevalence of tremor in the multiple sclerosis (MS) population among studies ranged widely, between 12.5% and 68.9%. The presence of severe tremor ranged from 3% to 33%. Younger age was a significant predictor of tremor in two studies. The most common tremor subtype was action tremor. Upper extremities were the most common site involved in the majority of our studies, followed by head and neck. CONCLUSIONS: Prevalence of tremor ranged from 12.5% to 68.9% in the MS population with severe tremor being an infrequent complication. Severity of tremor correlated with increasing disability. Upper limb action tremor was the most common with rare occurrences of resting and rubral tremor.