Movement disorders in multiple sclerosis

Paroxysmal dystonia as a rare initial manifestation of multiple sclerosis

Multiple sclerosis is an uncommon disease in childhood and adolescence and is rarely associated with movement disorders other than tremor. The differential diagnosis is difficult to establish when, particularly, movement disorder presents as the initial manifestation of multiple sclerosis. Video-electroencephalography monitoring is the gold-standard method for the differential diagnosis of epileptic and paroxysmal nonepileptic events, including movement disorders and psychogenic seizures. This article presents a patient with paroxysmal dystonia secondary to multiple sclerosis who previously was diagnosed and treated as having conversion disorder and epilepsy. The utility of video-electroencephalography monitoring during the process of differential diagnosis is discussed.

Mgat5 deficiency in T cells and experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) is an inflammatory demyelinating and neurodegenerative disease initiated by autoreactive T cells. Mgat5, a gene in the Asn (N-) linked protein glycosylation pathway, associates with MS severity and negatively regulates experimental autoimmune encephalomyelitis (EAE) and spontaneous inflammatory demyelination in mice. N-glycan branching by Mgat5 regulates interaction of surface glycoproteins with galectins, forming a molecular lattice that differentially controls the concentration of surface glycoproteins. T-cell receptor signaling, T-cell proliferation, T_H1 differentiation, and CTLA-4 endocytosis are inhibited by Mgat5 branching. Non-T cells also contribute to MS pathogenesis and express abundant Mgat5 branched N-glycans. Here we explore whether Mgat5 deficiency in myelin-reactive T cells is sufficient to promote demyelinating disease. Adoptive transfer of myelin-reactive Mgat5^−/− T cells into Mgat5^+/+ versus Mgat5^−/− recipients revealed more severe EAE in the latter, suggesting that Mgat5 branching deficiency in recipient naive T cells and/or non-T cells contribute to disease pathogenesis.

Head tremor secondary to MS resolved with rituximab

We describe the case of a 33-year-old woman who presented with a 2-month history of worsening head tremor. The medical evaluation led to the new diagnosis of MS and the MRI of brain demonstrated prominently active disease. Intravenous rituximab was started according to the HERMES trial, and significant improvement was noted. She has received additional rituximab dosing approximately every 6 months, and at the 2-year follow-up the tremor has not recurred. The resolution of head tremor likely resulted from the complete suppression of MS disease activity, which must have allowed restoration of normal neural circuitry. In agreement with a growing body of evidence that supports early control of MS disease activity to prevent accumulation of fixed disability, this case advocates for aggressive immunological therapy at the onset of tremor in MS patients.

White matter: beyond focal disconnection

The complex phenomenology of white matter dementia and many neuropsychiatric disorders implies that they originate from involvement of distributed neural networks, and white matter neuropathology is increasingly implicated in the pathogenesis of these network disconnection syndromes. White matter disorders produce functional asynchrony of interdependent cerebral regions subserving normal cognitive and emotional functions. Accumulating evidence suggests that white matter dementia primarily reflects disturbed frontal systems connectivity, whereas disruption of frontal and temporal lobe systems is implicated in the pathogenesis of neuropsychiatric disorders. Continued study of normal and abnormal white matter promises to help resolve challenging problems in behavioral neurology and neuropsychiatry.

Movement disorders in patients with multiple sclerosis

Apart from tremor and restless-legs syndrome, abnormal involuntary movements are uncommon in patients with multiple sclerosis. A review of the literature in multiple sclerosis reveals case reports of a variety of other movement disorders such as myoclonus, spasmodic torticollis, paroxysmal dystonia, chorea, ballism, and parkinsonism. This chapter presents a thorough review of these movement disorders in multiple sclerosis patients and provides readers with potential underlying pathogenetic mechanisms.

Rapidly progressive course of very late onset multiple sclerosis presenting with Parkinsonism: case report

Multiple sclerosis mainly affects young adolescents, making late-onset multiple sclerosis a rarity and diagnostic challenge, particularly for cases after age 80 years. We present an 82-year-old patient with multiple sclerosis with very late onset. As well as spastic paraplegia, additional Parkinsonism secondary to demyelination in the basal ganglia was observed in this case. In most publications, spinal cord lesions were more common in late-onset multiple sclerosis which, in contrast, could not be found in our case. Despite different treatment strategies, rapid clinical deterioration and death after about 2 years of disease course occurred. Further discrimination in late-onset multiple sclerosis (50–70 years) and multiple sclerosis with very late onset (above 70 years) might be considered. Future trials to elucidate potential benefit of immunosuppressive (and neuroprotective) therapies in these age groups are mandatory.

Paroxysmal symptoms in multiple sclerosis masquerading as transient ischaemic attacks

Paroxysmal demyelinating events produced sudden onset, transient, recurrent symptoms that were troublesome to our patient and puzzled the referring clinician who mistook them for transient ischaemic attacks or epilepsy. It was important to recognise the true nature of the underlying problem because the symptoms could then be readily treated; this is especially critical because the symptoms, in this case, represent a relapse of multiple sclerosis and, therefore, are significant for examination during the diagnosis.

Thalamic stimulation in multiple sclerosis: evidence for a ‘demyelinative thalamotomy’

The mechanism of action of deep brain stimulation (DBS) in the alleviation of tremor in multiple sclerosis (MS) and other neurological disorders is unknown. Moreover, whether the trauma accompanying this surgery is responsible for the induction of new MS plaques is controversial. Here we report the first description of the post-mortem imaging and pathologic findings in the brain of a MS patient who underwent thalamic DBS for the treatment of MS-induced tremor. MR imaging of formalin-fixed brain slices was carried out at 1.5, 3 and 7 Tesla and correlated with the histopathology. There were numerous demyelinative plaques in the white mater, cortex and deep gray matter. There were no plaques along the DBS tract within the sections that sampled the deep hemispheric white matter. However, deep within the thalamus focal demyelination approximated the tract, particularly in the region corresponding to the electrical field. The findings in this single case raise the possibility that focal demyelination may be induced by the electrical field and this may be responsible for long-lasting alleviation of tremor in the absence of continued electrostimulation.

Paroxysmal chorea as a relapse of myelopathy in a patient with neuromyelitis optica

Movement disorders secondary to intrinsic spinal cord disease are rare. Paroxysmal chorea has not yet been reported in the neuromyelitis optica (NMO). We report a 43-year-old woman with relapsing-remitting cervical myelopathy who developed paroxysmal chorea during clinical exacerbation of NMO. MRI scan of the cervical spine revealed a long segmental enhancing lesion, but brain MRI did not show any responsible abnormalities. Acute exacerbation of recurrent myelopathy in NMO may be associated with transient movement disorder.

Antiproliferative effects of essential oils and their major constituents in human renal adenocarcinoma and amelanotic melanoma cells

OBJECTIVES

The purpose of this study was to evaluate cytotoxic activity of Platycladus orientalis, Prangos asperula and Cupressus sempervirens ssp. pyramidalis essential oils and to identify active components involved in inhibition of population growth of human cancer cell lines.

MATERIALS AND METHODS

Essential oils were obtained by hydrodistillation and were analysed by gas chromatography and gas chromatography coupled to mass spectrometry. Antiproliferative activity was tested on amelanotic melanoma C32 cells and on renal cell adenocarcinoma cells, using the sulphorhodamine B assay.

RESULTS

Cupressus sempervirens ssp. pyramidalis leaf oil exerted the highest cytotoxic activity with an IC(50)value of 104.90 microg/mL against C32, followed by activity of P. orientalis and P. asperula on the renal adenocarcinoma cell line (IC(50) of 121.93 and 139.17 microg/mL, respectively). P. orientalis essential oil was also active against amelanotic melanoma with an IC(50) of 330.04 microg/mL. Three identified terpenes, linalool, beta-caryophyllene and alpha-cedrol, were found to be active on both cell lines tested.

CONCLUSIONS

Our findings provide novel insights into the field of cytotoxic properties of essential oils. This study provided evidence on how cytotoxic activity of the oils is not always related to their major constituents, except for lower activity found in both cell lines for alpha-cedrol. Interestingly, beta-caryophyllene and linalool exhibited comparable IC(50) values to the commercial drug vinblastine on the ACHN cell line. This opens a new field of investigation to discover mechanisms responsible for the observed activity.

Movement disorders in multiple sclerosis: causal or coincidental association?

Despite the relatively frequent involvement of the basal ganglia and subthalamic nucleus by multiple sclerosis (MS) plaques, movement disorders (MD), other than tremor secondary to cerebellar or brainstem lesions, are uncommon clinical manifestations of MS. MD were present in 12 of 733 patients with MS (1.6%): three patients had parkinsonism, two blepharospasm, five hemifacial spasm, one hemidystonia, and one tourettism. MD in patients with MS are often secondary to demyelinating disease. Also in cases without response to steroid treatment and demyelinating lesions in critical regions, it is not possible to exclude that MD and MS are causally related.

Investigation of paroxysmal dystonia in a patient with multiple sclerosis: a transcranial magnetic stimulation study

OBJECTIVE

To study the pathogenesis of paroxysmal dystonia affecting the right body side in a patient with a demyelinating lesion in the descending motor pathways, also involving the basal ganglia.

METHODS

Single-pulse transcranial magnetic stimulation (TMS) was applied to study motor evoked potentials (MEPs) and the following silent periods (SPs) in the first dorsal interosseous muscle (FDI) of both sides and in the right extensor carpi radialis muscle (ECR) during voluntary contractions performed outside the dystonic attacks. During the dystonic paroxysms, single-pulse TMS was used to investigate the time course of MEPs and SPs in both FDI and ECR of the right side. Furthermore, paired-pulse TMS was applied at rest to investigate short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) in both FDI muscles.

RESULTS

At rest SICI and ICF were normal in both motor cortices. During voluntary contraction the MEP was smaller and the SP was longer in the affected FDI than in the contralateral. During the paroxysms, the MEPs and SPs were suppressed in comparison with the responses elicited during voluntary contraction.

CONCLUSIONS

These results fit well with the theory of ephaptic excitement of corticospinal axons for the pathogenesis of paroxysmal dystonia due to a demyelinating lesion.

SIGNIFICANCE

Identification of the mechanisms underlying paroxysmal dystonia in demyelinating disorders extends our knowledge on the pathophysiology of dystonia.

Paroxysmal dystonia and pathological laughter as a first manifestation of multiple sclerosis

Paroxysmal dystonia is an uncommon but well-established feature of multiple sclerosis (MS). Attacks can occur in established MS and may even occasionally be the initial symptom of this disorder. Pathological laughter is usually seen as a pseudobulbar palsy in some diffuse neurological diseases, but cases have been described, mostly in ischaemic attacks or tumours, where it is presented as bursts of laughter of variable duration. The pathogenesis of neither of the two phenomena has been fully established but both have been reported as being positive phenomena resulting from ectopic activation with ephaptic spread. We describe the first reported case of a paroxysmal hemidystonia together with bursts of pathological laughter as the first manifestation of MS. Multiple Sclerosis 2008; 14: 262—265. http://msj.sagepub.com

N-glycan processing deficiency promotes spontaneous inflammatory demyelination and neurodegeneration

Multiple sclerosis (MS) is characterized by inflammatory demyelination of axons and neurodegeneration, the latter inadequately modeled in experimental autoimmune encephalomyelitis (EAE). Susceptibility of inbred mouse strains to EAE is in part determined by major histocompatibility complex haplotype; however, other molecular mechanisms remain elusive. Galectins bind GlcNAc-branched N-glycans attached to surface glycoproteins, forming a molecular lattice that restricts lateral movement and endocytosis of glycoproteins. GlcNAc branching negatively regulates T cell activity and autoimmunity, and when absent in neurons, induces apoptosis in vivo in young adult mice. We find that EAE susceptible mouse strains PL/J, SJL, and NOD have reduced GlcNAc branching. PL/J mice display the lowest levels, partial deficiencies in N-acetylglucosaminyltransferase I, II, and V (i.e. Mgat1, -2, and -5), T cell hyperactivity and spontaneous late onset inflammatory demyelination and neurodegeneration; phenotypes markedly enhanced by Mgat5(+/-) and Mgat5(-/-) backgrounds in a gene dose-dependent manner. Spontaneous disease is transferable and characterized by progressive paralysis, tremor, dystonia, neuronophagia, and axonal damage in both demyelinated lesions and normal white matter, phenocopying progressive MS. Our data identify hypomorphic Golgi processing as an inherited trait that determines susceptibility to EAE, provides a unique spontaneous model of MS, and suggests GlcNAc-branching deficiency may promote T cell-mediated demyelination and neurodegeneration in MS.

Progressive myoclonic ataxia with intrathecal immune activation in six patients

In six patients with slowly progressive sporadic cerebellar ataxia and cortical multifocal action myoclonus, cerebrospinal fluid (CSF) IgG index was persistently very high (1.2-6.7) and numerous oligoclonal bands were detected. Progressive cognitive impairment and MRI cerebellar and cerebral atrophy were observed. No serum antibodies were found. Various degenerative, metabolic, inflammatory and systemic diseases were excluded. The cerebellum may be the main target of a degenerative or immune process and releases antigens that, enhancing a compartmentalised (auto)immune response, as suggested by the persistent intrathecal activation, could lead to further cerebellar damage. As the frequency of CSF oligoclonal banding in myoclonic ataxia is unknown, our patients' disease might represent a hitherto unreported entity or a subset of progressive myoclonic ataxia.

Kinematic analysis of thalamic versus subthalamic neurostimulation in postural and intention tremor

Deep brain stimulation of the thalamus (thalamic DBS) is an established therapy for medically intractable essential tremor and tremor caused by multiple sclerosis. In both disorders, motor disability results from complex interaction between kinetic tremor and accompanying ataxia with voluntary movements. In clinical studies, the efficacy of thalamic DBS has been thoroughly assessed. However, the optimal anatomical target structure for neurostimulation is still debated and has never been analysed in conjunction with objective measurements of the different aspects of motor impairment. In 10 essential tremor and 11 multiple sclerosis patients, we analysed the effect of thalamic DBS through each contact of the quadripolar electrode on the contralateral tremor rating scale, accelerometry and kinematic measures of reach-to-grasp-movements. These measures were correlated with the anatomical position of the stimulating electrode in stereotactic space and in relation to nuclear boundaries derived from intraoperative microrecording. We found a significant impact of the stereotactic z-coordinate of stimulation contacts on the TRS, accelerometry total power and spatial deviation in the deceleration and target period of reach-to-grasp-movements. Most effective contacts clustered within the subthalamic area (STA) covering the posterior Zona incerta and prelemniscal radiation. Stimulation within this region led to a mean reduction of the lateralized tremor rating scale by 15.8 points which was significantly superior to stimulation within the thalamus (P < 0.05, student's t-test). STA stimulation resulted in reduction of the accelerometry total power by 99%, whereas stimulation at the ventral thalamic border (68%) or within the thalamus proper (2.5%) was significantly less effective (P < 0.01). Concomitantly, STA stimulation led to a significantly higher increase of tremor frequency and decrease in EMG synchronization compared to stimulation within the thalamus proper (P < 0.001). In reach-to-grasp movements, STA stimulation reduced the spatial variability of the movement path in the deceleration period by 28.9% and in the target period by 58.4%, whereas stimulation within the thalamus was again significantly less effective (P < 0.05), with a reduction in the deceleration period between 6.5 and 21.8% and in the target period between 1.2 and 11.3%. An analysis of the nuclear boundaries from intraoperative microrecording confirmed the anatomical impression that most effective electrodes were located within the STA. Our data demonstrate a profound effect of deep brain stimulation of the thalamic region on tremor and ataxia in essential tremor and tremor caused by multiple sclerosis. The better efficacy of stimulation within the STA compared to thalamus proper favours the concept of a modulation of cerebello-thalamic projections underlying the improvement of these symptoms.

Post-deep brain stimulation — gradual non-stimulation dependent decrease in strength with attenuation of multiple sclerosis tremor

Tremor in multiple sclerosis is considered to be a persistent and progressive sign. We describe five patients with multiple sclerosis in whom upper limb tremor severity gradually decreased over a period of several years after deep brain stimulation. In every case this attenuation of tremor was accompanied by increasing pyramidal weakness in the relevant upper limb. In two patients this attenuation of tremor remained after stimulation was permanently switched off. In one other patient, where upper limb strength remained normal, tremor severity gradually worsened in spite of continuing stimulation. There was a highly significant difference (p = 0.0007) between the changes in intention tremor severities when the arms with increasing pyramidal weakness (n = 9) were compared to those in which normal strength was retained throughout follow-up period (n = 3); intention tremor decreased in the former and increased in the latter by means of -3.66 and +4.0 points of a 0-10 tremor scale respectively. There was also a significant correlation (0.699; p = 0.0359) between decreasing upper limb strength and decreasing intention tremor severity for the upper limbs of patients that had undergone contralateral DBS.

A unique case of coincidence of early onset Parkinson's disease and multiple sclerosis

We report on a patient who developed left arm rest/postural tremor at age 24 and responded well to trihexyphenidyl. One year later spastic paraparesis appeared, and multiple sclerosis was diagnosed on the basis of clinical, radiological, and laboratory evidence. Although paraparesis improved after immunosuppressant therapy, a complete picture of an asymmetric parkinsonian syndrome gradually developed. Excellent response to levodopa, drug-induced dyskinesias, and DaTSCAN revealing pathology congruent with Parkinson's disease (PD) indicate a coincidental etiopathogenetic relationship of both clinical entities: multiple sclerosis and PD. Genetic analyses focusing on autosomal recessive parkinsonism (parkin, DJ1, and PINK1) were negative. To the best of our knowledge, only 15 cases of parkinsonism in association with multiple sclerosis have been reported, and their relationship has been interpreted to be either causal or coincidental. This is the first report of a coincidence of both entities, in which the parkinsonian syndrome developed first and before age 30.

Neurophysiologic intervention in deep brain stimulation treatment for movement disorders: a practical framework

Clinical neurophysiology has always played an important interventional role throughout the perioperative stages in functional neurosurgery. On the one hand, some neurophysiologic procedures have become an integrated part of neurosurgery. On the other hand, in deep brain stimulation, although the surgical electrode implantation is an essential step, the therapeutic effects are actually produced by electrically modulating the physiologic activity of the brain. We review the topic of neurophysiologic intervention in the deep brain stimulation for movement disorders by presenting the evidence derived from our own experiences based on an integrated group located at two hospitals in London and Oxford, UK, and mainly covering tremor caused by multiple sclerosis, Parkinson's disease and dystonia.

Thalamotomy versus thalamic stimulation for multiple sclerosis tremor

Disabling intractable tremor occurs frequently in patients with multiple sclerosis (MS). There is currently no effective medical treatment available, and the results of surgical intervention have been variable. Thalamotomy has been the mainstay of neurosurgical therapy for intractable MS tremor, however the popularisation of deep brain stimulation (DBS) has led to the adoption of chronic thalamic stimulation in an attempt to ameliorate this condition. With the goal of examining the relative efficacy and adverse effects of these two surgical strategies, we studied twenty carefully selected patients with intractable MS tremor. Thalamotomy was performed in 10 patients, with chronic DBS administered to the remaining 10. Both thalamotomy and thalamic stimulation produced improvements in postural and intention tremor. The mean improvement in postural tremor at 16.2 months following surgery was 78%, compared with a 64% improvement after thalamic stimulation (14.6 month follow-up) (P > 0.05). Intention tremor improved by 72% in the group undergoing thalamotomy, a significantly larger gain than the 36% tremor reduction following DBS (P < 0.05). Early postoperative complications were common in both groups. Permanent complications related to surgery occurred in four patients overall. Following thalamotomy, long-term adverse effects were observed in three patients (30%), and comprised hemiparesis and seizures. Only one patient in the thalamic stimulation group experienced a permanent deficit (monoparesis). We conclude that thalamotomy is a more efficacious surgical treatment for intractable MS tremor, however the higher incidence of persistent neurological deficits in patients receiving lesional surgery may support the use of DBS as the preferred surgical strategy.

An update on conventional and advanced magnetic resonance imaging techniques in the differential diagnosis of neurodegenerative parkinsonism

PURPOSE OF REVIEW

The clinical differentiation between Parkinson's disease and atypical parkinsonian disorders (APD) remains a challenge for every neurologist. Conventional magnetic resonance imaging (MRI) and different advanced MRI techniques offer the potential for objective criteria in the differential diagnosis of neurodegenerative parkinsonism. The aim of this article is to review the recent literature on the role of conventional and advanced MRI techniques in the differential diagnosis of neurodegenerative parkinsonian disorders.

RECENT FINDINGS

An important role of MRI is the exclusion of symptomatic parkinsonism due to other pathologies. Over the past two decades, conventional MRI and different advanced MRI techniques, including proton magnetic resonance spectroscopy (1H-MRS), diffusion-weighted imaging (DWI), magnetization transfer imaging (MTI) and magnetic resonance volumetry (MRV) have been found to show abnormalities in the substantia nigra and basal ganglia, especially in APD. Recent studies using MRV, MTI, DWI and 1H-MRS to discriminate Parkinson's disease from APD are discussed extensively.

SUMMARY

Research findings suggest that novel MRI techniques such as MTI, DWI and MRV have superior sensitivity compared to conventional MRI in detecting abnormal features in neurodegenerative parkinsonian disorders. Whether these techniques will emerge as standard investigations in the work-up of patients presenting with parkinsonism requires further prospective magnetic resonance studies during early disease stages.

Dystonia in a 13-year-old boy with secondary progressive multiple sclerosis

We report a patient who developed relapsing-remitting multiple sclerosis (MS) at 8 years old, and then had a progressive clinical course and dystonia. Dystonia of the patient is probably due to a lesion of the basal ganglia. Abnormal posture or movement disorder is very rarely found in MS, and progressive clinical course is also rare in childhood. The patient is worthy of attention because of his childhood onset, progressive clinical course and dystonia.

Subthalamic lesion and paroxysmal tonic spasms

Paroxysmal dyskinesia due to a subthalamic lesion is a rare finding. We describe a patient with paroxysmal tonic spasms due to a well-defined lesion in the subthalamic area. In this case, we confirm the nonepileptic nature of the episode and collect with detail the clinical features by means of a video-electroencephalographic recording. We also report an excellent response to carbamazepine in subthalamic paroxysmal dyskinesias.

Paroxysmal kinesigenic dyskinesias

The paroxysmal dyskinesias (PxDs) are involuntary, intermittent movement disorders manifested by dystonia, chorea, athetosis, ballismus or any combination of these hyperkinetic disorders. Paroxysmal kinesigenic dyskinesia (PKD), one of the four main types of PxD, involves sudden attacks of dyskinesias induced by voluntary movements. PKD most commonly occurs sporadically or as an autosomal-dominant familial trait with variable penetrance. Many causes of secondary PKD are being recognized. The exact pathophysiology of the PxDs awaits further elucidation, although basal ganglia dysfunction appears to play a major role. Although the precise gene remains unknown, genetic linkage studies have isolated loci on chromosome 16, which colocalizes with the locus for familial infantile convulsions and paroxysmal choreoathetosis in some studies. The episodic nature of PKD and its relationship with other episodic diseases, such as epilepsy, migraine, and episodic ataxia, suggests channelopathy as a possible underlying etiology. PKD may remit spontaneously, but it also responds well to anticonvulsants as well as some other agents.

Parkinsonism as a manifestation of multiple sclerosis

We describe a 48-year-old patient, with a diagnosis of relapsing-remitting multiple sclerosis, who presented to our service with a parkinsonian syndrome that markedly improved after corticosteroid treatment. To the best of our knowledge, only 12 cases of parkinsonism have been reported from 1970 to the present, of which only 8 seemed secondary to MS, i.e., those presenting conclusive imaging evidence or unequivocal response to corticosteroids.

Simple phonic tic in multiple sclerosis

Movement disorders occurring in association with multiple sclerosis (MS) are rare. Among them paroxysmal dystonia is the most common, although chorea, ballism, palatal myoclonia, spasmodic torticollis, writer's cramp and generalized dystonia have been reported. We describe a 34-year old woman with MS who developed simple phonic tic characterized by throat-clearing sounds. Magnetic resonance imaging showed demyelinating lesions involving the thalamus and basal ganglia. This is the first report of tic disorder occurring as a manifestation of MS.

Movement disorders in the tropics

The spectrum of movement disorders in the tropics is different from that seen in the industrialized nations of the west. This is not surprising given the unique combination of environmental and population characteristics in the tropics. Infections seldom encountered in the west such as tuberculous meningitis, typhoid fever, Japanese encephalitis, malaria, trypanosomiasis or cysticercosis are often seen in the tropics and with global patterns of travel and immigration these conditions are becoming more common worldwide. Movement disorders associated with these infections, HIV, slow virus and prion disease are discussed. Taking into account the diverse etiologies of movement disorders in the tropics, movement disorders with a nutritional basis such as the infantile tremor syndrome, seasonal ataxia and tropical ataxic neuropathy, and manganese neurotoxicity are also reviewed. Finally, certain special characteristics of ubiquitous disorders such as Parkinson's disease, and disorders with a genetic basis such as Wilson's disease and spinocerebellar degeneration are described.

Transient movement disorders and multiple sclerosis

Movement disorders associated with multiple sclerosis (MS) are uncommon, except for tremor. We report two patients with relapsing-remitting MS, who developed either dystonia or chorea during clinical exacerbation of their MS. The movement disorders resolved during treatment with adrenocorticotropin hormone (ACTH). Acute exacerbations of MS may be associated with transient movement disorders, which are responsive to ACTH.

Thalamic deep brain stimulation for the treatment of tremor due to multiple sclerosis: a prospective study of tremor and quality of life

OBJECT

In several studies a significant reduction in tremor after thalamic deep brain stimulation (DBS) has been reported among patients with multiple sclerosis (MS). It has not been determined if this results in an improved quality of life. In this study the authors prospectively evaluated the effects of thalamic DBS on tremor and quality of life.

METHODS

Videotapes of the patients' tremor were made preoperatively and 2 and 12 months postoperatively, and tremor was scored by a neurologist blinded to the treatment. Patients were tested pre- and postoperatively to measure any changes in their reported ability to perform selected activities of daily living and in their health-related quality of life. Patients were asked to complete a questionnaire about their satisfaction with the surgery. Postoperative changes were examined using paired t-tests. There were significant reductions in postural, action, and overall tremor at 2 and 12 months postoperatively. The patients' reported ability to feed themselves was significantly improved 2 months after surgery (p = 0.01). There were short-term trends toward improvement in reported dressing ability, personal hygiene, and writing. There were no significant changes in the SF-36 subscales or total score.

CONCLUSIONS

In this cohort of patients with MS who suffered from tremor, thalamic DBS significantly improved their tremor and ability to feed themselves. Patient satisfaction with the procedure, however, was variable. Preoperative patient education about what functions might (and might not) be improved is crucial to avoid unrealistic expectations. Our results indicate that younger patients with MS tremor who had a shorter disease duration and no superimposed ataxia benefited most from this surgery.

Post-streptococcal autoimmune neuropsychiatric disease presenting as paroxysmal dystonic choreoathetosis

Paroxysmal dystonic choreoathetosis (PDC) is an episodic, non-kinesogenic, extrapyramidal movement disorder. It is postulated that PDC is an ion channel disorder. We describe a sporadic case of paroxysmal dystonic choreoathetosis occurring after streptococcal pharyngitis. The episodes were characterized by abrupt-onset dystonic posturing, choreoathetosis, visual hallucinations and behavioral disturbance. Each episode lasted between 10 minutes and 4 hours, and occurred up to 4 times per day. In between attacks, examination was normal. The episodes waxed and waned in frequency during a 6-month illness. Magnetic resonance imaging of the brain was normal. Post-streptococcal neuropsychiatric disease has a proposed autoimmune etiology, which is supported by the presence of serum antibasal ganglia antibodies. Western immunoblotting of this case's serum demonstrated antibody binding to a basal ganglia antigens of molecular weight 80 kDa and 95 kDa. Immunohistochemistry examination demonstrated specific antibody binding to large striatal neurones. We propose that autoantibodies produced in post-streptococcal neuropsychiatric disease cause alteration in neurotransmission, possibly secondary to ion channel binding.

Secondary paroxysmal dyskinesias

Paroxysmal dyskinesias (PxDs) are involuntary, episodic movements that include paroxysmal kinesigenic (PKD), paroxysmal nonkinesigenic (PNKD), and paroxysmal hypnogenic (PHD) varieties. Although most PxDs are primary (idiopathic or genetic), we found 17 of our 76 patients with PxD (22%) to have an identifiable cause for their PxD (10 men; mean age, 41.4 years). Causes included peripheral trauma (in three patients), vascular lesions (in four), central trauma (in four), kernicterus (in two), multiple sclerosis (in one), cytomegalovirus encephalitis (in one), meningovascular syphilis (in one), and migraine (in one). The latency from insult to symptom onset ranged from days (trauma) to 18 years (kernicterus), with a mean of 3 years. Nine patients had PNKD, two had PKD, five had mixed PKD/PNKD, and one had PHD. Hemidystonia was the most common expression of the paroxysmal movement disorder, present in 11 patients. Both of the patients with PKD had symptom durations of <5 minutes. Symptom duration ranged from 10 seconds to 15 days for PNKD and from 5 minutes to 45 minutes for mixed PKD/PNKD. There were no uniformly effective therapies, but anticonvulsant drugs, clonazepam, and botulinum toxin injections were the most beneficial. Awareness of the variable phenomenology and the spectrum of causes associated with secondary PxD will allow for more timely diagnosis and early intervention.

Management of spasticity, pain, and paroxysmal phenomena in multiple sclerosis

Multiple sclerosis (MS) is a disease with tremendous variability and innumerable symptoms. Among the more common symptoms is spasticity. Despite a lack of full knowledge of the physiology causing this phenomenon, successful treatments have been developed. Many of these have had a recent introduction. Pain and paroxysmal phenomena are surprisingly common in MS, but have not had the recognition their frequency deserves. It is not unusual to hear that they are rare in MS, but surprisingly they are all too common. Their management is changing as newer treatments are developed.

Symptomatic paroxysmal hemidystonia due to a demyelinating subthalamic lesion

We present a case of paroxysmal hemidystonia in a patient with an isolated demyelinating lesion in the subthalamic region, involving the posterior arm of the internal capsule and extending to the subthalamic nucleus and mesencephalon, possibly due to multiple sclerosis. Compared with similar reports in the literature, in our case there was a paucity of lesions, permitting a more direct clinico-anatomical correlation. The role of the subthalamic region and basal ganglia circuitry in the genesis of symptomatic dystonia is discussed.

Hemidystonia secondary to cervical demyelinating lesions

Hemidystonia is usually associated with a structural lesion in the contralateral basal ganglia. We report a patient with definite multiple sclerosis, according to Poser's criteria, presenting with an acute-onset sustained left hemidystonia. Cranial T2-weighted magnetic resonance imaging (MRI) showed several hyperintense lesions in the centri semiovali and in the periventricular area without basal ganglia involvement. Moreover cervical spinal cord T2-weighted MRI showed two hyperintense lesions in the left posterolateral spine at C2 and C3, and one lesion in the right posterolateral spine at C4 levels. The hemidystonia improved completely after daily treatment with 1000 mg of methylprednisolone, and cervical MRI was performed after the improvement which showed that the lesions had become smaller and less intense. Finally we consider that the hemidystonia may be caused by the cervical spinal cord lesions of multiple sclerosis.

Paroxysmal dyskinesias as a paradigm of paroxysmal movement disorders

Paroxysmal dyskinesias are genetically and clinically heterogeneous. Paroxysmal kinesigenic choreoathetosis is frequently familial, with autosomal-dominant transmission. Benign infantile convulsions can be observed in these families and both diseases as linked to the pericentromeric region of chromosome 16. Two different forms of paroxysmal dystonic choreoathetosis are distinguished on clinical grounds, by the presence or absence of spasticity, and genetically, as they are linked with loci on different chromosomes. Among the paroxysmal disorders, these diseases may belong to the group of channelopathies.

Neurophysiological investigations in multiple sclerosis

The advent of magnetic resonance imaging techniques has greatly reduced the diagnostic value of neurophysiological tests, particularly evoked potentials, in multiple sclerosis patients, because of the higher sensitivity in revealing subclinical involvement of the central nervous system. Technical progress and new methods of investigating afferent and efferent nervous pathways would seem to increase the sensitivity in detecting neural dysfunction, but the 'clinical gain' is modest at best. More promising is the utilization of neurophysiological tests to quantify the severity of white matter involvement. Transversal and longitudinal studies have demonstrated good correlations between neurophysiological parameters and disability measures, indicating that a battery of neurophysiological tests could be useful in monitoring the disease evolution in single patients and as surrogate endpoints in clinical trials. Further studies are needed for a better definition of the applications of evoked potentials and other neurophysiological techniques. Finally, event-related potentials and advanced electroencephalogram techniques, such as coherence analysis, could provide useful information on the pathophysiology of cognitive dysfunction, so common in multiple sclerosis patients, and with a strong impact on the quality of life.

Reciprocal inhibition between the forearm muscles in patients with paroxysmal kinesigenic dyskinesia

We measured the changes of forearm flexor H reflexes produced by conditioning radial nerve stimulation at delays of -2, 0, 2, 4, 7.5, 10, 25 and 75 ms in 10 patients with PKD and six with generalized seizure disorder. We compared the results with 12 normal volunteers. In the patients with PKD, we compared the amounts of reciprocal inhibition between the severely and the asymptomatic or mildly affected sides of arms. Follow-up studies were done in eight PKD patients after they responded to the anticonvulsant treatment. At each delay, patients with seizure disorders showed comparable amounts of changes with controls. Patients with PKD showed paradoxical facilitation at a delay of 0 ms, enhanced facilitation between 2 to 7.5 ms delays and attenuated inhibition at a delay of 75 ms. There were no significant differences in the amount of reciprocal inhibition according to the severity of clinical symptoms. Follow-up studies showed no significant changes of reciprocal inhibition compared to the baseline data. In PKD, paradoxical facilitation and enhanced first relative facilitation period may be caused by defective spinal interneurons. In addition to the defective reciprocal inhibition, abnormalities of supraspinal inputs seem to be involved in the genesis of PKD.

Anatomic correlates of painful tonic spasms in multiple sclerosis

Painful tonic spasms (PTS) are now regarded as a typical symptom of multiple sclerosis but pathologic or radiologic findings rarely have been described. We report clinical and magnetic resonance imaging records of five original cases. In all of them, lesions likely responsible for unilateral PTS involved the motor pathway at the level of the posterior limb of the internal capsule or the cerebral peduncle on the opposite side. Closeness of motor fibers seems to be the most important underlying anatomic factor because it enables involvement of a higher proportion of axons by a single demyelinating lesion and radial spread of ephaptic activation. In turn, preservation of the underlying pyramidal-spinal tract could make it easier for the pathologic discharge to reach the peripheral effectors and generate PTS.