Spinal Movement Disorders in Neuromyelitis Optica: An Under‐recognized Phenomenon

Abstract

Background: Spinal cord demyelination can cause several movement disorders. Although these abnormal movements could be the presenting symptom of the disease and, at times, the major source of disability, they are often overlooked, mislabeled, or undertreated. The aims of this study were to clearly define and establish common terminology for spinal movement disorders (SMDs) and characterize their full spectrum in patients with neuromyelitis optica (NMO). Methods: We chart reviewed 37 patients with NMO or NMO spectrum disorder. We classified spinal movement disorders under five categories: tonic spasms; focal dystonia; spinal myoclonus; spontaneous clonus; and tremors of spinal origin. We examined clinical, MRI, and medication data of symptomatic patients. Results: Of the 37 patients (86.4% female; mean age: 51 AE 17 years; mean disease duration: 9.4 AE 5.3 years), 16 (43.2%) had one or more form of SMDs. Compared to those without SMDs, patients with SMDs were generally older at presentation and were less likely to be African Americans. An abnormal movement was the main complaint in at least one posthospitalization visit in all symptomatic patients. Thirteen (35.1%) patients had paroxysmal tonic spasms, 2 (5.4%) had focal dystonia, 3 (8%) had postural/ action tremors, and no patient had spinal myoclonus or spontaneous clonus. In 9 patients, spasms were painful. There was no signal abnormality in the basal ganglia or the brainstem/cerebellum in any of the symptomatic patients. Conclusions: SMDs are common in NMO and are often a major source of disability. Using clear, unified terminology to describe SMDs is crucial for both clinical and research purposes.The prototype pathological substrates for movement disorders are the basal ganglia, other deep subcortical nuclei, the cerebellum, and their connections in the brainstem.

Movement disorders in early MS and related diseases

“…Per our previously reported definition, 6 11 patients (18.3%) had focal paroxysmal dystonia of the upper or lower extremity following a well-defined spinal (8) or brainstem relapse (1). One patient with primary progressive MS had focal dystonia from a right thalamic lesion and in one patient the origin was undetermined.…”

Pain in NMOSD and MOGAD: A Systematic Literature Review of Pathophysiology, Symptoms, and Current Treatment Strategies

“…Several case reports and small series describe PTS in NMOSD ( 18 , 29 , 29 – 31 , 65 – 67 , 136 , 141 – 144 ), but no reports were identified mentioning PTS in MOGAD. Abboud et al reported that all patients with tonic spasms had associated neuropathic pain ( 145 ). PTS and pain occur more frequently in NMOSD than in MS ( 18 , 29 ), and PTS-associated myelitis in AQP4-Ab-positive NMOSD has been described with a specificity of 98.7% compared to MS ( 143 ).…”

Symptomatic and restorative therapies in neuromyelitis optica spectrum disorders

“…Focal spinal cord disease can cause a variety of involuntary movements including tonic spasms, paroxysmal or fixed focal dystonia, spinal myoclonus, spontaneous or triggered clonus, spinal tremor, and secondary restless leg syndrome (RLS) [33][34][35]. Some of these movement disorders, in particular tonic spams and paroxysmal dystonia, are thought to be more common in NMOSD than other demyelinating diseases and they can be painful [36][37][38][39].…”

“…Some of these movement disorders, in particular tonic spams and paroxysmal dystonia, are thought to be more common in NMOSD than other demyelinating diseases and they can be painful [36][37][38][39]. The prevalence of any spinal movement disorder in NMOSD is estimated at 43% while the prevalence rates for tonic spasms in particular range from 22 to 40% depending on the study [33,36,38]. They commonly occur several weeks to months following a spinal attack but they can occasionally be the presenting symptom of a new spinal relapse [33].…”

“…They commonly occur several weeks to months following a spinal attack but they can occasionally be the presenting symptom of a new spinal relapse [33]. Tonic spasms and other involuntary movements have a significant impact in NMOSD and are among the most bothersome residual symptoms [33,36,38]. Demyelination-related involuntary movements and other paroxysmal events are thought to result from ephaptic transmission of nerve impulses in the demyelinated fibers and are believed to respond to standard doses of anti-seizure medications especially sodium channel blockers like carbamazepine and oxcarbazepine [33,34].…”