Movement Disorders in Multiple Sclerosis: An Update

Abstract

Background: Multiple sclerosis (MS), a subset of chronic primary inflammatory demyelinating disorders of the central nervous system, is closely associated with various movement disorders. These disorders may be due to MS pathophysiology or be coincidental. This review describes the full spectrum of movement disorders in MS with their possible mechanistic pathways and therapeutic modalities. Methods:The authors conducted a narrative literature review by searching for 'multiple sclerosis' and the specific movement disorder on PubMed until October 2021. Relevant articles were screened, selected, and included in the review according to groups of movement disorders. Results:The most prevalent movement disorders described in MS include restless leg syndrome, tremor, ataxia, parkinsonism, paroxysmal dyskinesias, chorea and ballism, facial myokymia, including hemifacial spasm and spastic paretic hemifacial contracture, tics, and tourettism. The anatomical basis of some of these disorders is poorly understood; however, the link between them and MS is supported by clinical and neuroimaging evidence. Treatment options are disorder-specific and often multidisciplinary, including pharmacological, surgical, and physical therapies.Discussion: Movements disorders in MS involve multiple pathophysiological processes and anatomical pathways. Since these disorders can be the presenting symptoms, they may aid in early diagnosis and managing the patient, including monitoring disease progression. Treatment of these disorders is a challenge. Further work needs to be done to understand the prevalence and the pathophysiological mechanisms responsible for movement disorders in MS.

Effects of intrathecal Baclofen in reducing tremors in patients with multiple sclerosis

“…The most common form of tremor in MS patients are a combination of postural and intention tremors. 2 The pathophysiology of tremors in MS patients is poorly understood, however lesions in cerebello-thalamocortical pathways and/or central sensory and motor pathways could contribute to the pathogenesis of either tremors or dysmetria. 3 In turn, therapeutic options for MS tremors include pharmacological agents, botulinum toxin A injections, along with deep brain stimulation or thalamotomy for drug resistant or severe, disabling tremors, but the evidence remains inconclusive regarding a definite approach.…”

“… 1 Along with nystagmus and scanning speech, French neurologist Charcot (1825–1893) identified tremors as one of the three hallmark symptoms of MS. Tremors in MS patients are caused by lesions in either the motor and sensory tract or cerebello-thalamo-cortical circuits. 2 , 3 From 25% to 58% of MS patients experience tremors, which are in turn linked to a poor prognosis and higher disability. 4 , 5 Tremors are challenging to control since they resist symptomatic treatment.…”

Neuroimmune, clinical and treatment challenges in multiple sclerosis-related psychoses

“…Researchers also presumed that patients with MS had an unexpected sensitivity to antipsychotic drugs[ 84 ]. MS is closely related to various movement disorders[ 85 ]. However, clinicians should be aware that movement disorders can also represent adverse drug reactions caused by chronic antipsychotic therapy[ 86 ], especially in cases of polypharmacy.…”

Identifying the white matter pathways involved in multiple sclerosis-related tremor using diffusion tensor imaging

“…2 Current treatment modalities for MS-related tremor are lacking in their justification, measured efficacy, or outcomes. 4 Deep brain stimulation is one of the few available options for severe medication-resistant tremor, though, it shows limited efficacy in treating MS-related tremor compared to essential tremor or Parkinson's disease-related tremor 5 while causing permanent adverse effects in up to 25% of the cases. 6 One reason may be that MS differs fundamentally from other causes of tremor with variable topography of pathology in the brain and spinal cord.…”

“…Many studies on MS-related tremor are conducted with prior assumptions of involved neurocircuitry drawn from other causes of tremor, often scrutinizing cerebello-thalamocortical networks. 4,7,8 Diffusion tensor imaging (DTI) is a reliable, validated technique that quantitatively assesses random water mobility, providing information about the tissue microstructure integrity measured in terms of diffusivity. 9 In a medium without an oriented microstructure, diffusivity is similar in three axial directions.…”