Movement disorders in relapsing and progressive MS: A comprehensive prospective evaluation of a large real-life...

Recent studies suggest that movement disorders are common in early MS. However, the frequency and clinical characteristics of movement disorders at all stages of MS remain unknown.

To evaluate the frequency, clinical characteristics, and anatomical generators of movement disorders in relapsing and progressive MS.

We conducted a prospective study of adult MS patients from 2016 to 2022 at a neuroimmunology clinic. Patients were evaluated for demyelination-related movement disorders via a survey and focused examination. We classified movement disorders based on phenomenology and identified anatomic correlates according to lesion locations and relation to relapses. Findings were compared between relapsing and progressive MS.

Of 327 patients, 211 (64.5 %) had demyelination-related movement disorders (median age 35.3, Q1 28.5, Q3 44.8; 72.5 % female). Spinal movement disorders were the most common and occurred in 177 patients (54.1 %). Brainstem/cerebellar movement disorders occurred in 59 (18 %), and striatal/thalamic movement disorders occurred in 8 (2.4 %). The most common movement subtypes were tonic spasms (39.4 %) and tremor (24.5 %). We observed 21 cases (6.4 %) in which movement disorders represented a new relapse including the first attack of the disease. Patients with progressive MS were more likely to have demyelination-related movement disorders (chi square, p < 0.001), including spinal (chi square, p = 0.0003), brainstem/cerebellar (chi square, p = 0.009), and striatal/thalamic movement disorders (fisher exact, p = 0.03).

Demyelination-related movement disorders are very common in all stages of MS, especially in patients with progressive disease and those with spinal lesions. In some, movement disorders may be the presenting symptom of the disease.