Movement disorders in multiple sclerosis

Timely and Personalized Interventions and Vigilant Care in Neurodegenerative Conditions: The FIT4TeleNEURO Pragmatic Trial

Parkinson's disease (PD) and multiple sclerosis (MS) are two chronic neurological diseases (CNDs) that have a high demand for early and continuous rehabilitation. However, accessing professional care remains a challenge, making it a key priority to identify sustainable solutions for ensuring early rehabilitation availability. Objective: The FIT4TeleNEURO pragmatic trial proposes to investigate, in real-life care settings, the superiority in terms of the effectiveness of early rehabilitation intervention with harmonized, mix-model telerehabilitation (TR) protocols (TR single approach, task-oriented-TRsA; TR combined approach, task-oriented and impairment-oriented-TRcA) compared to conventional management (control treatment, CeT) in people with PD and MS. Design, and Methods: This multicenter, randomized, three-treatment arm pragmatic trial will involve 300 patients with CNDs (PD, N = 150; MS, N = 150). Each participant will be randomized (1:1:1) to the experimental groups (20 sessions of TRsA or TRcA according to a mix-model-3 asynchronous + 1 synchronous session/week) or the control group (20 sessions of CeT). Primary and secondary outcome measures will be obtained at the baseline (T0), post-intervention (T1, 5 weeks after baseline), and follow-up (T2, 3 months after the end of the treatment). A multidimensional evaluation (cognitive, motor, and quality of life domains) will be conducted at each time point of assessment (T0; T1; T2). The primary outcome measures will be the assessment of change (T0 vs. T1 vs. T2) in static and dynamic balance, measured using the Mini-Balance Evaluation Systems Test. Usability and acceptability assessment will be also investigated. Expected Results: Implementing TR protocols will enable a more targeted and efficient response to the growing demand for rehabilitation in the early stages of CNDs. Both the TRsA and TRcA approaches are expected to be more effective than CeT, with the combined approach likely providing greater benefits in secondary outcome measures. Finally, the acceptability of the asynchronous modality could open the door to scalable solutions, such as digital therapeutics.

Differential diagnosis of chorea (guidelines of the German Neurological Society)

INTRODUCTION

Choreiform movement disorders are characterized by involuntary, rapid, irregular, and unpredictable movements of the limbs, face, neck, and trunk. These movements often initially go unnoticed by the affected individuals and may blend together with seemingly intended, random motions. Choreiform movements can occur both at rest and during voluntary movements. They typically increase in intensity with stress and physical activity and essentially cease during deep sleep stages. In particularly in advanced stages of Huntington disease (HD), choreiform hyperkinesia occurs alongside with dystonic postures of the limbs or trunk before they typically decrease in intensity. The differential diagnosis of HD can be complex. Here, the authors aim to provide guidance for the diagnostic process. This guidance was prepared for the German Neurological Society (DGN) for German-speaking countries.

RECOMMENDATIONS

Hereditary (inherited) and non-hereditary (non-inherited) forms of chorea can be distinguished. Therefore, the family history is crucial. However, even in conditions with autosomal-dominant transmission such as HD, unremarkable family histories do not necessarily rule out a hereditary form (e.g., in cases of early deceased or unknown parents, uncertainties in familial relationships, as well as in offspring of parents with CAG repeats in the expandable range (27-35 CAG repeats) which may display expansions into the pathogenic range).

CONCLUSIONS

The differential diagnosis of chorea can be challenging. This guidance prepared for the German Neurological Society (DGN) reflects the state of the art as of 2023.

Non-Immersive Virtual Reality Telerehabilitation System Improves Postural Balance in People with Chronic Neurological Diseases

BACKGROUND

People with chronic neurological diseases, such as Parkinson's Disease (PD) and Multiple Sclerosis (MS), often present postural disorders and a high risk of falling. When difficulties in achieving outpatient rehabilitation services occur, a solution to guarantee the continuity of care may be telerehabilitation. This study intends to expand the scope of our previously published research on the impact of telerehabilitation on quality of life in an MS sample, testing the impact of this type of intervention in a larger sample of neurological patients also including PD individuals on postural balance.

METHODS

We included 60 participants with MS and 72 with PD. All enrolled subjects were randomized into two groups: 65 in the intervention group and 67 in the control group. Both treatments lasted 30-40 sessions (5 days/week, 6-8 weeks). Motor, cognitive, and participation outcomes were registered before and after the treatments.

RESULTS

All participants improved the outcomes at the end of the treatments. The study's primary outcome (Mini-BESTest) registered a greater significant improvement in the telerehabilitation group than in the control group.

CONCLUSIONS

Our results demonstrated that non-immersive virtual reality telerehabilitation is well tolerated and positively affects static and dynamic balance and gait in people with PD and MS.

Voxel-wise lesion mapping of restless legs syndrome in multiple sclerosis

Objective

Restless legs syndrome (RLS) is known to be associated with multiple sclerosis (MS) and may be caused by MS lesions in specific cerebral brain regions. Applying a voxel-wise lesion analysis, we tried to identify the contribution of cerebral MS lesions to RLS.

Methods

In this retrospective study, we established a cohort of people with MS with documented RLS and controls of people with MS without RLS matched disease severity. Diagnosis of MS and RLS was based on the current guidelines. The MS lesions were analyzed on T2-weighted magnetic resonance imaging scans (1.5 or 3 T). After manual delineation, lesion maps were converted into stereotaxic space. We generated a lesion overlap and performed a Liebermeister test with 4000 permutations to compare the absence or presence of RLS voxel-wise between patients with and without lesions in a given voxel.

Results

Forty of the patients with RLS and MS fulfilled the inclusion criteria. The voxel-wise analysis yielded associations between RLS and MS in the subcortex of the left gyrus precentralis.

Conclusion

Our voxel-wise analysis shows associations in the subcortex of the left gyrus precentralis. Thus, our data suggests that a dysfunction of the efferent motor system due to cerebral lesions may contribute to the pathophysiology of RLS in MS.

Movement Disorders in Multiple Sclerosis: An Update

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.

The etiopathogenetic and pathophysiological spectrum of parkinsonism

Parkinsonism is a syndrome characterized by bradykinesia, rigidity, and tremor. Parkinsonism is a common manifestation of Parkinson's disease and other neurodegenerative diseases referred to as atypical parkinsonism. However, a growing body of clinical and scientific evidence indicates that parkinsonism may be part of the phenomenological spectrum of various neurological conditions to a greater degree than expected by chance. These include neurodegenerative conditions not traditionally classified as movement disorders, e.g., dementia and motor neuron diseases. In addition, parkinsonism may characterize a wide range of central nervous system diseases, e.g., autoimmune diseases, infectious diseases, cerebrospinal fluid disorders (e.g., normal pressure hydrocephalus), cerebrovascular diseases, and other conditions. Several pathophysiological mechanisms have been identified in Parkinson's disease and atypical parkinsonism. Conversely, it is not entirely clear to what extent the same mechanisms and key brain areas are also involved in parkinsonism due to a broader etiopathogenetic spectrum. We aimed to provide a comprehensive and up-to-date overview of the various etiopathogenetic and pathophysiological mechanisms of parkinsonism in a wide spectrum of neurological conditions, with a particular focus on the role of the basal ganglia involvement. The paper also highlights potential implications in the diagnostic approach and therapeutic management of patients. This article is part of the Special Issue "Parkinsonism across the spectrum of movement disorders and beyond" edited by Joseph Jankovic, Daniel D. Truong and Matteo Bologna.

Evaluation of the potassium channel tracer [18F]3F4AP in rhesus macaques

Demyelination causes slowed or failed neuronal conduction and is a driver of disability in multiple sclerosis and other neurological diseases. Currently, the gold standard for imaging demyelination is MRI, but despite its high spatial resolution and sensitivity to demyelinated lesions, it remains challenging to obtain specific and quantitative measures of molecular changes involved in demyelination. To understand the contribution of demyelination in different diseases and to assess the efficacy of myelin-repair therapies, it is critical to develop new in vivo imaging tools sensitive to changes induced by demyelination. Upon demyelination, axonal K⁺ channels, normally located underneath the myelin sheath, become exposed and increase in expression, causing impaired conduction. Here, we investigate the properties of the K⁺ channel PET tracer [¹⁸F]3F4AP in primates and its sensitivity to a focal brain injury that occurred three years prior to imaging. [¹⁸F]3F4AP exhibited favorable properties for brain imaging including high brain penetration, high metabolic stability, high plasma availability, high reproducibility, high specificity, and fast kinetics. [¹⁸F]3F4AP showed preferential binding in areas of low myelin content as well as in the previously injured area. Sensitivity of [¹⁸F]3F4AP for the focal brain injury was higher than [¹⁸F]FDG, [¹¹C]PiB, and [¹¹C]PBR28, and compared favorably to currently used MRI methods.

Current challenges in the pathophysiology, diagnosis, and treatment of paroxysmal movement disorders

INTRODUCTION

Paroxysmal movement disorders mostly comprise paroxysmal dyskinesia and episodic ataxia, and can be the consequence of a genetic disorder or symptomatic of an acquired disease.

AREAS COVERED

In this review, the authors focused on certain hot-topic issues in the field: the respective contribution of the cerebellum and striatum to the generation of paroxysmal dyskinesia, the importance of striatal cAMP turnover in the pathogenesis of paroxysmal dyskinesia, the treatable causes of paroxysmal movement disorders not to be missed, with a special emphasis on the treatment strategy to bypass the glucose transport defect in paroxysmal movement disorders due to GLUT1 deficiency, and functional paroxysmal movement disorders.

EXPERT OPINION

Treatment of genetic causes of paroxysmal movement disorders is evolving towards precision medicine with targeted gene-specific therapy. Alteration of the cerebellar output and modulation of the striatal cAMP turnover offer new perspectives for experimental therapeutics, at least for paroxysmal movement disorders due to selected causes. Further characterization of cell-specific molecular pathways or network dysfunctions that are critically involved in the pathogenesis of paroxysmal movement disorders will likely result in the identification of new biomarkers and testing of innovative-targeted therapeutics.

Palatal Tremor - Pathophysiology, Clinical Features, Investigations, Management and Future Challenges

Background:

Palatal tremor is involuntary, rhythmic and oscillatory movement of the soft palate. Palatal tremor can be classified into three subtypes; essential, symptomatic and palatal tremor associated with progressive ataxia.

Methods:

A thorough Pubmed search was conducted to look for the original articles, reviews, letters to editor, case reports, and teaching neuroimages, with the keywords “essential”, “symptomatic palatal tremor”, “myoclonus”, “ataxia”, “hypertrophic”, “olivary” and “degeneration”.

Results:

Essential palatal tremor is due to contraction of the tensor veli palatini muscle, supplied by the 5^th cranial nerve. Symptomatic palatal tremor occurs due to the contraction of the levator veli palatini muscle, supplied by the 9%^th and 10%^th cranial nerves. Essential palatal tremor is idiopathic, while symptomatic palatal tremor occurs due to infarction, bleed or tumor within the Guillain-Mollaret triangle. Progressive ataxia and palatal tremor can be familial or idiopathic. Symptomatic palatal tremor and sporadic progressive ataxia with palatal tremor show signal changes in inferior olive of medulla in magnetic resonance imaging. The treatment options available for essential palatal tremor are clonazepam, lamotrigine, sodium valproate, flunarizine and botulinum toxin. The treatment of symptomatic palatal tremor involves the treatment of the underlying cause.

Discussion:

Further studies are required to understand the cause and pathophysiology of Essential palatal tremor and progressive ataxia and palatal tremor. Similarly, the link between tauopathy and palatal tremor associated progressive ataxia needs to be explored further. Oscillopsia and progressive ataxia are more debilitating than palatal tremor and needs new treatment approaches.

Paroxysmal Symptoms in Multiple Sclerosis-A Review of the Literature

Paroxysmal symptoms are well-recognized manifestations of multiple sclerosis (MS). These are characterized by multiple, brief, sudden onset, and stereotyped episodes. They manifest as motor, sensory, visual, brainstem, and autonomic symptoms. When occurring in the setting of an established MS, the diagnosis is relatively straightforward. Conversely, the diagnosis is significantly more challenging when they occur as the initial manifestation of MS. The aim of this review is to summarize the various forms of paroxysmal symptoms reported in MS, with emphasis on the clinical features, radiological findings and treatment options.

Review of Hereditary and Acquired Rare Choreas

Background:

Movement disorders are often a prominent part of the phenotype of many neurologic rare diseases. In order to promote awareness and diagnosis of these rare diseases, the International Parkinson’s and Movement Disorders Society Rare Movement Disorders Study Group provides updates on rare movement disorders.

Methods:

In this narrative review, we discuss the differential diagnosis of the rare disorders that can cause chorea.

Results:

Although the most common causes of chorea are hereditary, it is critical to identify acquired or symptomatic choreas since these are potentially treatable conditions. Disorders of metabolism and mitochondrial cytopathies can also be associated with chorea.

Discussion:

The present review discusses clues to the diagnosis of chorea of various etiologies. Authors propose algorithms to help the clinician in the diagnosis of these rare disorders.

Non-inflammatory causes of emergency consultation in patients with multiple sclerosis

OBJECTIVES

To describe non-relapse-related emergency consultations of patients with multiple sclerosis (MS): causes, difficulties in the diagnosis, clinical characteristics, and treatments administered.

METHODS

We performed a retrospective study of patients who attended a multiple sclerosis day hospital due to suspected relapse and received an alternative diagnosis, over a 2-year period. Demographic data, clinical characteristics, final diagnosis, and treatments administered were evaluated. Patients who were initially diagnosed with pseudo-relapse and ultimately diagnosed with true relapse were evaluated specifically. As an exploratory analysis, patients who consulted with non-inflammatory causes were compared with a randomly selected cohort of patients with true relapses who attended the centre in the same period.

RESULTS

The study included 50 patients (33 were women; mean age 41.4 ± 11.7 years). Four patients (8%) were initially diagnosed with pseudo-relapse and later diagnosed as having a true relapse. Fever and vertigo were the main confounding factors. The non-inflammatory causes of emergency consultation were: neurological, 43.5% (20 patients); infectious, 15.2% (7); psychiatric, 10.9% (5); vertigo, 8.6% (4); trauma, 10.9% (5); and miscellaneous, 10.9% (5).

CONCLUSIONS

MS-related symptoms constituted the most frequent cause of non-inflammatory emergency consultations. Close follow-up of relapse and pseudo-relapse is necessary to detect incorrect initial diagnoses, avoid unnecessary treatments, and relieve patients' symptoms.

Movement disorders in early MS and related diseases: A prospective observational study

BACKGROUND

Little 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.

METHODS

A 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.

RESULTS

Sixty 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.

CONCLUSION

Movement 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.

The clinical features, underlying immunology, and treatment of autoantibody-mediated movement disorders

An increasing number of movement disorders are associated with autoantibodies. Many of these autoantibodies target the extracellular domain of neuronal surface proteins and associate with highly specific phenotypes, suggesting they have pathogenic potential. Below, we describe the phenotypes associated with some of these commoner autoantibody‐mediated movement disorders, and outline increasingly well‐established mechanisms of autoantibody pathogenicity which include antigen downregulation and complement fixation. Despite these advances, and the increasingly robust evidence for improved clinical outcomes with early escalation of immunotherapies, the underlying cellular immunology of these conditions has received little attention. Therefore, here, we outline the likely roles of T cells and B cells in the generation of autoantibodies, and reflect on how these may guide both current immunotherapy regimes and our future understanding of precision medicine in the field. In addition, we summarise potential mechanisms by which these peripherally‐driven immune responses may reach the central nervous system. We integrate this with the immunologically‐relevant clinical observations of preceding infections, tumours and human leucocyte antigen‐associations to provide an overview of the therapeutically‐relevant underlying adaptive immunology in the autoantibody‐mediated movement disorders. © 2018 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Non-inflammatory causes of emergency consultation in patients with multiple sclerosis

OBJECTIVES

To describe non-relapse-related emergency consultations of patients with multiple sclerosis (MS): causes, difficulties in the diagnosis, clinical characteristics, and treatments administered.

METHODS

We performed a retrospective study of patients who attended a multiple sclerosis day hospital due to suspected relapse and received an alternative diagnosis, over a 2-year period. Demographic data, clinical characteristics, final diagnosis, and treatments administered were evaluated. Patients who were initially diagnosed with pseudo-relapse and ultimately diagnosed with true relapse were evaluated specifically. As an exploratory analysis, patients who consulted with non-inflammatory causes were compared with a randomly selected cohort of patients with true relapses who attended the centre in the same period.

RESULTS

The study included 50 patients (33 were women; mean age 41.4±11.7years). Four patients (8%) were initially diagnosed with pseudo-relapse and later diagnosed as having a true relapse. Fever and vertigo were the main confounding factors. The non-inflammatory causes of emergency consultation were: neurological, 43.5% (20 patients); infectious, 15.2% (7); psychiatric, 10.9% (5); vertigo, 8.6% (4); trauma, 10.9% (5); and miscellaneous, 10.9% (5).

CONCLUSIONS

MS-related symptoms constituted the most frequent cause of non-inflammatory emergency consultations. Close follow-up of relapse and pseudo-relapse is necessary to detect incorrect initial diagnoses, avoid unnecessary treatments, and relieve patients' symptoms.

Inherited and Acquired Choreas

Chorea is a symptom of a broad array of genetic, structural, and metabolic disorders. While chorea can result from systemic illness and damage to diverse brain structures, injury to the basal ganglia, especially the putamen or globus pallidus, appears to be a uniting features of these diverse neuropathologies. The timing of onset, rate of progression, and the associated neurological or systemic symptoms can often narrow the differential diagnosis to a few disorders. Recognizing the correct etiology for childhood chorea is critical, as numerous disorders in this category are potentially curable, or are remediable, with early treatment.

Hypertrophic Olivary Degeneration and Palatal or Oculopalatal Tremor

Hypertrophic degeneration of the inferior olive is mainly observed in patients developing palatal tremor (PT) or oculopalatal tremor (OPT). This syndrome manifests as a synchronous tremor of the palate (PT) and/or eyes (OPT) that may also involve other muscles from the branchial arches. It is associated with hypertrophic inferior olivary degeneration that is characterized by enlarged and vacuolated neurons, increased number and size of astrocytes, severe fibrillary gliosis, and demyelination. It appears on MRI as an increased T2/FLAIR signal intensity and enlargement of the inferior olive. There are two main conditions in which hypertrophic degeneration of the inferior olive occurs. The most frequent, studied, and reported condition is the development of PT/OPT and hypertrophic degeneration of the inferior olive in the weeks or months following a structural brainstem or cerebellar lesion. This “symptomatic” condition requires a destructive lesion in the Guillain–Mollaret pathway, which spans from the contralateral dentate nucleus via the brachium conjunctivum and the ipsilateral central tegmental tract innervating the inferior olive. The most frequent etiologies of destructive lesion are stroke (hemorrhagic more often than ischemic), brain trauma, brainstem tumors, and surgical or gamma knife treatment of brainstem cavernoma. The most accepted explanation for this symptomatic PT/OPT is that denervated olivary neurons released from inhibitory inputs enlarge and develop sustained synchronized oscillations. The cerebellum then modulates/accentuates this signal resulting in abnormal motor output in the branchial arches. In a second condition, PT/OPT and progressive cerebellar ataxia occurs in patients without structural brainstem or cerebellar lesion, other than cerebellar atrophy. This syndrome of progressive ataxia and palatal tremor may be sporadic or familial. In the familial form, where hypertrophic degeneration of the inferior olive may not occur (or not reported), the main reported etiologies are Alexander disease, polymerase gamma mutation, and spinocerebellar ataxia type 20. Whether or not these are associated with specific degeneration of the dentato–olivary pathway remain to be determined. The most symptomatic consequence of OPT is eye oscillations. Therapeutic trials suggest gabapentin or memantine as valuable drugs to treat eye oscillations in OPT.

Paroxysmal Kinesigenic Dyskinesia as the Presenting and Only Manifestation of Multiple Sclerosis after Eighteen Months of Follow-Up

Other than tremor, movement disorders are uncommon in multiple sclerosis. Among these uncommon clinical manifestations, paroxysmal kinesigenic dyskinesia is the most frequently reported. It is characterized by episodic attacks of involuntary movements that are induced by repetitive or sudden movements, startling noise or hyperventilation. The diagnosis is essentially clinical and based on a good observation of the attacks. It is very easy to misdiagnose it. We describe the case of a young female patient who presented paroxysmal kinesigenic dyskinesia as the first and only clinical manifestation of multiple sclerosis, with no recurrence of attacks nor any other neurologic symptom after eighteen months of follow-up.

Movement disorders in multiple sclerosis and their treatment

Hyperkinetic movement disorders such as tremors are not uncommon in patients with multiple sclerosis (MS). The classical feature is intention tremor, whereas rest tremors appear not to occur. Treatment is mainly invasive, with options of Gamma Knife surgery, thalamotomy or deep brain stimulation depending on individual circumstances. Deep brain stimulation is the only option for patients who require a bilateral intervention. All treatment recommendations have only low evidence. Tremors can also be cured spontaneously by a subsequent strategic MS lesion. Paroxysmal dyskinesias are rarer than tremors. The rarest MS movement disorder is symptomatic paroxysmal choreoathetosis, tonic spasms or ‘brain stem fits’; attacks are short but frequent, up to 200 per day and generally respond well to carbamazepine.

Paroxysmal movement disorders: An update

Paroxysmal movement disorders comprise both paroxysmal dyskinesia, characterized by attacks of dystonic and/or choreic movements, and episodic ataxia, defined by attacks of cerebellar ataxia. They may be primary (familial or sporadic) or secondary to an underlying cause. They can be classified according to their phenomenology (kinesigenic, non-kinesigenic or exercise-induced) or their genetic cause. The main genes involved in primary paroxysmal movement disorders include PRRT2, PNKD, SLC2A1, ATP1A3, GCH1, PARK2, ADCY5, CACNA1A and KCNA1. Many cases remain genetically undiagnosed, thereby suggesting that additional culprit genes remain to be discovered. The present report is a general overview that aims to help clinicians diagnose and treat patients with paroxysmal movement disorders.

Changes in Multidigit Synergies and Their Feed-Forward Adjustments in Multiple Sclerosis

The authors explored the changes in multidigit synergies in patients with multiple sclerosis (MS) within the framework of the uncontrolled manifold hypothesis. The specific hypotheses were that both synergy indices and anticipatory synergy adjustments prior to the initiation of a self-paced quick action would be diminished in the patients compared to age-matched controls. The MS patients and age-matched controls (n = 13 in both groups) performed one-finger and multifinger force production tasks involving both accurate steady-state force production and quick force pulses. The patients showed significantly lower maximal finger forces and a tendency toward slower force pulses. Enslaving was increased in MS, but only in the lateral fingers (index and little). Indices of multifinger synergies during steady-state force production were lower in MS, mainly due to the lower amount of intertrial variance that did not affect total force. Anticipatory synergy adjustments were significantly delayed in MS. The results show that MS leads to significant changes in multidigit synergies and feed-forward adjustments of the synergies prior to a quick action. The authors discuss possible contributions of subcortical structures to the impaired synergic control.

Cutaneous and Mixed Nerve Silent Period Recordings in Symptomatic Paroxysmal Kinesigenic Dyskinesia

Objective:

The underlying neurophysiologic mechanism responsible for secondary paroxysmal kinesigenic dyskinesia (PKD) is still unclear. Here, we study the pathogenesis of PKD in two patients with a demyelinating lesion in the spinal cord.

Methods:

Electromyogram recordings from affected arms of two patients with spinal cord lesions presenting PKD were compared with our laboratory standards. The cutaneous silent period (CuSP), mixed nerve silent period (MnSP) and coincidence period (CiP), defined as the common period between the CuSP and MnSP, were recorded.

Results:

A large decrease in the MnSP and disappearance of the CiP were observed in our patients, which was secondary to simultaneous extinction of the third portion of the MnSP, while the CuSP was normal. The MnSP and CiP were normal after recovery.

Conclusions:

Our results demonstrate that the third portion of the MnSP and the CuSP do not correspond to the same physiologic process. These findings suggest that PKD patients have abnormal spinal interneuron integration.

Co-occurrence of multiple sclerosis and Parkinson disease

Parkinson disease (PD) is a neurodegenerative disease of the central nervous system (CNS) with the highest prevalence in adults over 60 years of age On the other hand multiple sclerosis (MS), which mostly affects individuals between 20 and 40 years of age, is another neurodegenerative and autoimmune disease of the CNS, however, less common than PD. Here we aim to report the case of a 39-year-old woman, who developed PD 18 years after diagnosis of MS.

Motor Skill Acquisition Promotes Human Brain Myelin Plasticity

Experience-dependent structural changes are widely evident in gray matter. Using diffusion weighted imaging (DWI), the neuroplastic effect of motor training on white matter in the brain has been demonstrated. However, in humans it is not known whether specific features of white matter relate to motor skill acquisition or if these structural changes are associated to functional network connectivity. Myelin can be objectively quantified in vivo and used to index specific experience-dependent change. In the current study, seventeen healthy young adults completed ten sessions of visuomotor skill training (10,000 total movements) using the right arm. Multicomponent relaxation imaging was performed before and after training. Significant increases in myelin water fraction, a quantitative measure of myelin, were observed in task dependent brain regions (left intraparietal sulcus [IPS] and left parieto-occipital sulcus). In addition, the rate of motor skill acquisition and overall change in myelin water fraction in the left IPS were negatively related, suggesting that a slower rate of learning resulted in greater neuroplastic change. This study provides the first evidence for experience-dependent changes in myelin that are associated with changes in skilled movements in healthy young adults.

Paroxysmal dystonia as a manifestation of multiple sclerosis

INTRODUCTION

Paroxysmal dystonia is a rare manifestation of multiple sclerosis (MS).

CASE REPORT

A 41-year-old man presented to our Emergency Department with sudden and repeated episodes of left upper limb flexion and lower limb extension. His medical history included an episode of left facial palsy a year earlier. Neurological examination demonstrated only brisk deep tendon reflexes on the left upper limb. Routine blood and urine analyses were normal. Computed tomography of the brain and cervical Doppler were normal. Aspirin and sodium valproate were started, without improvement. Video-EEG monitoring revealed no electrographic abnormality synchronous with these paroxysmal events, excluding epileptic nature. Cerebral magnetic resonance imaging showed multiple T2 white matter lesions at the midbrain, right diencephalon, corpus callosum, cervical, and thoracic spinal cord. The right diencephalic lesion enhanced with gadolinium. Complete basic and immunologic analysis and serological studies were normal or negative. Oligoclonal bands were positive in cerebrospinal fluid (negative in serum). Methylprednisolone (1 g/d for 5 d) was started without clinical improvement. Carbamazepine (400 mg/d) was promptly effective, and discontinued after 1 month without recurrence.

DISCUSSION

The patient met the criteria for the diagnosis of MS according to the 2010 McDonald criteria. The timely and accurate diagnosis of MS requires the recognition of its varied and atypical clinical manifestations.

Spinal-generated movement disorders: a clinical review

Spinal-generated movement disorders (SGMDs) include spinal segmental myoclonus, propriospinal myoclonus, orthostatic tremor, secondary paroxysmal dyskinesias, stiff person syndrome and its variants, movements in brain death, and painful legs-moving toes syndrome. In this paper, we review the relevant anatomy and physiology of SGMDs, characterize and demonstrate their clinical features, and present a practical approach to the diagnosis and management of these unusual disorders.

The occurrence of dystonia in upper-limb multiple sclerosis tremor

BACKGROUND

The pathophysiology of multiple sclerosis (MS) tremor is uncertain with limited phenotypical studies available.

OBJECTIVE

To investigate whether dystonia contributes to MS tremor and its severity.

METHODS

MS patients (n = 54) with and without disabling uni- or bilateral upper limb tremor were recruited (39 limbs per group). We rated tremor severity, writing and Archimedes spiral drawing; cerebellar dysfunction (SARA score); the Global Dystonia Scale (GDS) for proximal and distal upper limbs, dystonic posturing, mirror movements, geste antagoniste, and writer's cramp.

RESULTS

Geste antagoniste, mirror dystonia, and dystonic posturing were more frequent and severe (p < 0.001) and dystonia scores were correlated with tremor severity in tremor compared to non-tremor patients. A 1-unit increase in distal dystonia predicted a 0.52-Bain unit (95% confidence interval (CI) 0.08-0.97), p = 0.022) increase in tremor severity and a 1-unit (95% CI 0.48-1.6, p = 0.001) increase in drawing scores. A 1-unit increase in proximal dystonia predicted 0.93-Bain unit increase (95% CI 0.45-1.41, p < 0.001) in tremor severity and 1.5-units (95% CI 0.62-2.41, p = 0.002) increase in the drawing score. Cerebellar function in the tremor limb and tremor severity was correlated (p < 0.001).

CONCLUSIONS

Upper limb dystonia is common in MS tremor suggesting that MS tremor pathophysiology involves cerebello-pallido-thalamo-cortical network dysfunction.

Assessment of upper limb motor function in patients with multiple sclerosis using the Virtual Peg Insertion Test: a pilot study

Quantifying and tracking upper limb impairment is of key importance to the understanding of disease progress, establishing patient-tailored therapy protocols and for optimal care provision. This paper presents the results of a pilot study on the assessment of upper limb motor function in patients with multiple sclerosis (MS) with the Virtual Peg Insertion Test (VPIT). The test consists in a goal-directed reaching task using a commercial haptic display combined with an instrumented handle and virtual environment, and allows for the extraction of objective kinematic and dynamic parameters. Ten MS patients and eight age-matched healthy subjects performed five repetitions of the VPIT with their dominant and non-dominant hand. Upper limb movements were found to be significantly slower, less smooth and less straight compared to healthy controls, and the time to complete the VPIT was well correlated with the conventional Nine Hole Peg Test (r=0.658, p<0.01). Tremor in the range of 3-5 Hz could be detected and quantified using a frequency analysis in patients featuring intention tremor. These preliminary results illustrate the feasibility of using the VPIT with MS patients, and underline the potential of this test to evaluate upper limb motor function and discriminate characteristic MS related impairments.

Multiple sclerosis symptom management

Multiple sclerosis (MS) is the most common cause of nontraumatic disability in young adults. The increasing emphasis on early treatment with disease-modifying therapies has the goal of preventing long-term disability. However, current disease treatments are only partially effective, and most patients experience a variety of neurologic symptoms at various times during their disease course. Because these symptoms often have a profound impact on social, occupational and physical performance, effective symptom management is an important component of therapy to maintain quality of life. Effective symptom management often requires a multidisciplinary team approach. This review outlines general principles of the management of MS symptoms.

[Paroxysmal dystonia and multiple sclerosis]

INTRODUCTION

Movement disorders are uncommon in multiple sclerosis, except for tremor. Patients rarely have paroxysmal dystonia (or tonic spasm), which can be the presenting manifestation of the disease.

OBSERVATIONS

Two videotaped observations are presented. The first patient was a 27-year-old woman, treated for relapsing-remitting multiple sclerosis, who presented daily several short (<1minute) paroxysms of right hemibody dystonia. Brain MRI revealed several areas of cerebral demyelination, including the posterior limb of the left internal capsule with gadolinium enhancement. These events disappeared 7 days after corticosteroid infusion. The second patient was a 62-year-old man who presented brief episodes (<1minute) of daily painful left hemibody dystonia. Three months later, similar paroxysms affecting the right hemibody including the face occurred. At times, the two hemibodies were affected simultaneously. The brain MRI showed multiple areas of white matter hyperintensity, including two symmetrical areas in the posterior limb of the internal capsules. Multiple sclerosis was diagnosed on clinical, MRI and biological data. Four days after starting corticosteroids, these paroxysmal phenomena disappeared totally.

CONCLUSION

Dystonia is an under-recognized aspect of paroxysmal events during multiple sclerosis. It might involve ephaptic transmission among abnormal demyelinated neurons; this ectopic excitation can arise at variable levels of the corticospinal tract, but the analysis of reported cases and those described in this study shows that impairment of the posterior limb of the internal capsule seems to be a prevalent topography. Inflammation is likely to play a role because steroids often improve these phenomena. In this article, we review the clinical aspects, pathophysiology and outcome of paroxysmal dystonia in multiple sclerosis.

Multiple sclerosis and risk of Parkinson's disease: a Danish nationwide cohort study

BACKGROUND AND PURPOSE

Case reports have observed a co-occurrence of multiple sclerosis (MS) and Parkinson's disease (PD) and it has been hypothesized that MS lesions could affect dopaminergic pathways causing parkinsonism. Our aim was to examine the association between MS and PD in a historically prospective cohort study using Danish nationwide register data.

METHODS

Multiple sclerosis patients identified in the Multiple Sclerosis Registry were followed for PD from 1977 to 2011 in the National Patient Register. As measures of relative risk, ratios of observed to expected incidence rates of first hospitalization for PD amongst persons with MS were used, i.e. standardized incidence ratios (SIRs) with 95% confidence intervals (CIs).

RESULTS

Amongst 15,557 MS patients 26 cases of PD were observed versus 26.51 expected, reflecting no overall increased risk of PD (SIR 0.98, 95% CI 0.67-1.44). Similar estimates were seen for female (SIR 0.99, 95% CI 0.58-1.67) and male MS patients (SIR 0.97, 95% CI 0.55-1.72). Likewise, no increased risk of PD amongst MS patients was observed in a robustness analysis backdating the date of diagnosis of PD by 5 years to account for the time lag between disease onset and first hospital contact with PD (SIR 0.57, 95% CI 0.32-1.00).

CONCLUSION

Our data do not suggest an increased risk of PD amongst patients with MS.

Risperidone-Induced Pisa Syndrome in MS

Objective: To report a case of risperidone-induced Pisa syndrome in a patient with multiple sclerosis (MS) that resolved with lurasidone, recurred with chlorpromazine, and was complicated by possible drug-drug interactions. Case Summary: A 31-year-old white male with MS developed Pisa syndrome after years of treatment with risperidone at varying doses for behavioral symptoms associated with pervasive developmental disorder. The patient experienced improvement in symptoms after treatment was switched to lurasidone; however, due to psychiatric decompensation, a switch to chlorpromazine was made and Pisa syndrome recurred. To maintain control of the patient’s behavioral symptoms, chlorpromazine was not discontinued. Discussion: Pisa syndrome is a rare adverse drug reaction induced most often by neuroleptic medications. The reaction is characterized by dystonia affecting cervical and lumbar musculature, resulting in flexion of the head and body to one side with axial rotation of the trunk. The etiology is believed to involve a dopaminergic-cholinergic imbalance. Most practitioners are not familiar with this syndrome, and it has not been reported previously in a patient with MS. Definitive diagnostic criteria and treatment have not been established. We identified 15 case reports involving risperidone, paliperidone, chlorpromazine, clomipramine, or valproic acid. The time to development of Pisa syndrome, patient demographics, dosing and titration of causative medications, approach to treatment, and resolution of Pisa syndrome varied widely in these reports. Dystonia in MS often presents differently than Pisa syndrome. The Naranjo probability scale indicated a probable relationship between either risperidone or chlorpromazine in each instance of Pisa syndrome in our patient. Conclusions: Pisa syndrome is a rare adverse drug reaction associated with neuroleptic medications. Our report highlights the importance of identifying this uncommon type of dystonia in order to consider modification of the medication regimen when appropriate.

Effects of low-frequency thalamic deep brain stimulation in essential tremor patients

BACKGROUND

Essential tremor (ET) patients may present with postural and/or intentional tremor. But despite high-frequency thalamic deep brain stimulation (DBS) effectively suppressing both, the emergence of intentional tremor has been attributed to a higher extent to cerebellar dysfunction. Therefore, we hypothesized thalamic 10 Hz-stimulation, which is known to worsen motor functions, having more impact on intentional tremor than on postural tremor.

METHODS

In sixteen ET-patients with bilateral thalamic-DBS, tremor rating scale (TRS) and ultrasound-based tremor-amplitude measurements were analyzed by sequentially applying three DBS-settings in a randomized order: i) low-frequency stimulation (LFS), ii) DBS being turned off (DBS-OFF) and iii) high-frequency stimulation (HFS). Repeated measures analyses of variance for TRS and for the quotients of tremor-amplitudes during DBS-OFF and LFS for intentional (q(int)) and postural tasks (q(post)) were calculated. Finally, electrode localization and the abovementioned quotients were put into relation by Pearson's correlation coefficient.

RESULTS

HFS reduced TRS significantly compared to DBS-OFF and LFS (ps<.001), while the latter two also differed significantly with TRS being the worst during LFS (p<.05). Additionally, intentional tremor-amplitude appeared to be strongly influenced by LFS than postural tremor-amplitude (p<.05). Furthermore, a lower placement of the electrodes caused worse intentional tremor-amplitude during LFS (r=.517, p>.05), while postural tremor-amplitude was unrelated to electrode localization (ps<.05).

CONCLUSIONS

During LFS in ET-patients, there is a more severe exacerbation of intentional tremor compared to postural tremor. Possibly, there are two different mechanisms responsible for both tremor entities, making more refined stimulation regimes feasible in the future.

Tonic spasms are a common clinical manifestation in patients with neuromyelitis optica

Tonic spasms have been most commonly associated with multiple sclerosis. To date, few reports of series of patients with neuromyelitis optica and tonic spasms have been published.

METHODS

We analyzed the characteristics and frequency of tonic spasms in 19 subjects with neuromyelitis optica. Data was collected using a semi-structured questionnaire for tonic spasms, by both retrospectively reviewing medical records and performing clinical assessment.

RESULTS

All patients except one developed this symptom. The main triggering factors were sudden movements and emotional factors. Spasms were commonly associated to sensory disturbances and worsened during the acute phases of the disease. Carbamazepine was most commonly used to treat the symptom and patients showed good response to the drug.

CONCLUSIONS

Tonic spasms are a common clinical manifestation in patients with neuromyelitis optica.

Stretching the limbs? Tonic spasms in multiple sclerosis

A 23-year-old man with a clinically isolated syndrome (right optic neuritis) diagnosed 6 months before, presented with recurrent, brief, painful, stereotyped, involuntary posturing movements of the left upper limb. The neurological examination was otherwise unremarkable (except for right optic atrophy). Intravenous methylprednisolone was initiated; the paroxysms persisted and worsened 7&emsp14;days later, as the left lower limb and hemiface became affected. A video-EEG showed no epileptiform activity despite the movements. Brain MRI revealed new lesions affecting the right pyramidal tract, contralateral to the clinical manifestations. Valproate was prescribed and the paroxysms were completely resolved 5 days later. Tonic spasms are classically, although infrequently, seen in multiple sclerosis, and may clinically resemble primary paroxysmal dyskinesias or even focal motor epileptic seizures.

Understanding tremor in multiple sclerosis: prevalence, pathological anatomy, and pharmacological and surgical approaches to treatment

Background

Given that tremor is one of the most prevalent and disabling features of multiple sclerosis (MS), we will review the most significant milestones in tremor in this disease in recent years, focusing on prevalence, clinical features, anatomical basis, and treatment.

Methods

Data for this review were identified by searching MEDLINE with the search terms “multiple sclerosis” and “tremor”. References were also identified from relevant articles published between January 1966 and May 2012.

Results

The predominant type of MS tremor is a large-amplitude, postural, and kinetic tremor, which most commonly affects the arms, although tremor can also involve head, neck, vocal cords, and trunk. Involvement of the tongue, jaw, or palate has not been reported. Although the anatomical basis underlying tremor in MS is poorly understood, the link between the cerebellum and the MS-related tremor is supported by clinical and experimental studies. Currently available medication is often unsuccessful in most cases. Surgical treatment can be a satisfactory alternative to treat severe and disabling tremor.

Discussion

Tremor in MS patients could be considered as an advanced consequence of the disease and its presence suggests a more aggressive course. MS tremor can be severe and very disabling for a small group of patients. Treatment of MS tremor remains a great challenge. Recent studies suggest that dissociating tremor from cerebellar dysfunction using selected clinical tests would be the key issue to successful surgical treatment. Understanding the pathophysiology and biochemistry of tremor production in MS may lead to new therapeutic approaches.

Movement disorders in autoimmune diseases

Movement disorders have been known to be associated with a variety of autoimmune diseases, including Sydenham's chorea, pediatric autoimmune neuropsychiatric disorders associated with streptococcus, systemic lupus erythematosus, antiphospholipid syndrome, gluten sensitivity, paraneoplastic and autoimmune encephalopathies. Tremors, dystonia, chorea, ballism, myoclonus, parkinsonism, and ataxia may be the initial and even the only presentation of these autoimmune diseases. Although antibodies directed against various cellular components of the central nervous system have been implicated, the pathogenic mechanisms of these autoimmune movement disorders have not yet been fully elucidated. Clinical recognition of these autoimmune movement disorders is critically important as many improve with immunotherapy or dietary modifications, particularly when diagnosed early. We discuss here the clinical features, pathogenic mechanisms, and treatments of movement disorders associated with autoimmune diseases, based on our own experience and on a systematic review of the literature.