Movement Disorders in Neuromyelitis Optica Spectrum Disorder: A Systematic Review

Background Several movement disorders (MD) have been reported to occur in neuromyelitis optica spectrum disorder (NMOSD). No extensive review has addressed the whole spectrum of MD in NMOSD. Objective This article aims to review MD in NMOSD, describing its prevalence and features. Methods A systematic review and prevalence meta‐analysis were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) reporting guidelines. We included articles on NMOSD patients with MD as defined by the 2015 international consensus criteria. Meta‐analysis was considered feasible if the prevalence of certain MDs was evaluated for at least 4 studies with more than 5 patients. Results Ninety‐six articles were selected from an initial pool of 5441, involving 1751 patients, of whom 487 had MD. The prevalence of anti‐aquaporin‐4 antibodies (AQP4‐IgG) was 79.9% in general and 78.7% in NMOSD‐MD patients. Tonic spasms/paroxysmal dystonia and ataxia were the most prevalent MD in NMOSD, with 39% and 26% prevalence, respectively. Tremor, parkinsonism, myoclonus, chorea, and other hyperkinetic disorders were more rarely reported. Conclusions A wide range of MDs in NMOSD were found, each with distinct features and frequency in literature. This knowledge might help to identify patients with NMOSD, which presents MD as a clinical feature and improves outcomes.