Movement disorders in early MS and related diseases

Abstract

BackgroundLittle is known about the true prevalence and clinical characteristics of movement disorders in early multiple sclerosis (MS) and related demyelinating diseases. We conducted a prospective study to fill this knowledge gap.MethodsA consecutive patient sample was recruited from the MS clinic within a 1-year-period. Patients diagnosed over 5 years before the study start date were excluded. Each eligible patient was interviewed by a movement disorder neurologist who conducted a standardized movement disorder survey and a focused examination. Each patient was followed prospectively for 1–4 follow-up visits. Movement disorders identified on examination were video-recorded and videos were independently rated by a separate blinded movement expert.ResultsSixty patients were included (56.6% female, mean age 38.3 ± 12.7 years). Eighty percent reported one or more movement disorders on the survey and 38.3% had positive findings on examination. After excluding incidental movement disorders (e.g., essential tremor), 58.3% were thought to have demyelination-related movement disorders. The most common movement disorders in a descending order were restless legs syndrome, tremor, tonic spasms, myoclonus, focal dystonia, spontaneous clonus, fasciculations, pseudoathetosis, hyperekplexia, and hemifacial spasm. The movement disorder started 5 months following a relapse on average but in 8 patients it was the presenting symptom of a new relapse or the disease itself. The majority of movement disorders occurred secondary to spinal (85.7%) or cerebellar/brainstem lesions (34.2%). Spinal cord demyelination was the only statistically significant predictor of demyelination-related movement disorders.ConclusionMovement disorders are more common than previously thought even in early MS. They typically begin a few months after spinal or brainstem/cerebellar relapses but may occasionally be the presenting symptom of a relapse.