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.