Pathological report of four patients presenting with cranial dystonias

Movement disorders of the mouth: a review of the common phenomenologies

Movement disorders of the mouth encompass a spectrum of hyperactive movements involving the muscles of the orofacial complex. They are rare conditions and are described in the literature primarily in case reports originating from neurologists, psychiatrists, and the dental community. The focus of this review is to provide a phenomenological description of different oral motor disorders including oromandibular dystonia, orofacial dyskinesia and orolingual tremor, and to offer management strategies for optimal treatment based on the current literature. A literature search of full text studies using PubMed/Medline and Cochrane library combined with a manual search of the reference lists was conducted until June 2021. Results from this search included meta-analyses, systematic reviews, reviews, clinical studies, case series, and case reports published by neurologists, psychiatrists, dentists and oral and maxillofacial surgeons. Data garnered from these sources were used to provide an overview of most commonly encountered movement disorders of the mouth, aiding physicians in recognizing these rare conditions and in initiating appropriate therapy.

Truncal dystonia with isolated middle cerebral artery ischemia: A case report of revascularization therapy for dystonia

Background:

Dystonia is a rare movement disorder with some cases being difficult to treat. Although dystonia can occur as a symptom of moyamoya disease, few studies have reported truncal dystonia occurring with middle cerebral artery (MCA) stenosis. Here, we report a case of truncal dystonia with MCA occlusion.

Case Description:

The patient was a 48-year-old female clerical worker who lived alone. An abnormal cervical posture initially appeared 7 years before (right flexion). Symptoms improved with medication and botulinum toxin injection. Five years before this report, her symptoms worsened, so the dose of oral medication was increased and botulinum treatment was performed, but the symptoms did not improve. The patient showed decreased cerebral blood flow (CBF) in the cortical areas but not in the basal ganglia. We performed superficial temporal artery-MCA bypass surgery because we believed that the dystonia was due to right MCA stenosis. The patient’s symptoms improved immediately after surgery, except for her mild cervical backbend. Seven months after the surgery, the patient’s involuntary movements showed further improvement, and symptoms have not worsened even after 2 years.

Conclusion:

Revascularization therapy improved CBF and truncal dystonia and could be a viable treatment option for dystonia with ischemia in the MCA region. Extensive cerebral ischemia can result in cortical inhibition loss or over-adapted cerebral plasticity and cause dystonia. Revascularization therapy may be useful for patients with dystonia and decreased CBF in the MCA region.

Blepharospasm as the presenting feature of papillary thyroid cancer and parathyroid adenoma

Blepharospasm is a type of focal dystonia depicted by periodic and spontaneous closure of the orbicularis oculi and surrounding muscles. Typical secondary etiologies of blepharospasm may include ophthalmologic and structural brain lesions. In this article, we report a novel case of a patient with a biopsy-proven concurrent papillary carcinoma of the thyroid gland and adenoma of the parathyroid gland with blepharospasm as an exceptionally unique initial manifestation. This report showed that a diagnostic work-up for causes of blepharospasm may include a search for these neoplasm and surgical removal of these masses may offer significant symptomatic control of the focal dystonia.

Multimodal Quantitative MRI Reveals No Evidence for Tissue Pathology in Idiopathic Cervical Dystonia

Background: While in symptomatic forms of dystonia cerebral pathology is by definition present, it is unclear so far whether disease is associated with microstructural cerebral changes in idiopathic dystonia. Previous quantitative MRI (qMRI) studies assessing cerebral tissue composition in idiopathic dystonia revealed conflicting results.

Objective: Using multimodal qMRI, the presented study aimed to investigate alterations in different cerebral microstructural compartments associated with idiopathic cervical dystonia in vivo.

Methods: Mapping of T₁, T₂, T2*, and proton density (PD) was performed in 17 patients with idiopathic cervical dystonia and 29 matched healthy control subjects. Statistical comparisons of the parametric maps between groups were conducted for various regions of interest (ROI), including major basal ganglia nuclei, the thalamus, white matter, and the cerebellum, and voxel-wise for the whole brain.

Results: Neither whole brain voxel-wise statistics nor ROI-based analyses revealed significant group differences for any qMRI parameter under investigation.

Conclusions: The negative findings of this qMRI study argue against the presence of overt microstructural tissue change in patients with idiopathic cervical dystonia. The results seem to support a common view that idiopathic cervical dystonia might primarily resemble a functional network disease.

Neuropathology of Dystonia

Background

Dystonia is characterized by sustained or intermittent muscle contractions resulting in abnormal, often repetitive, movements, postures, or both. Neuropathologic research has been essential in understanding the etiology and disease progression of other movement disorders, including Parkinson’s disease and cerebellar ataxias. In the field of dystonia, however, research is stymied by the paucity of post-mortem tissue available and the phenotypic heterogeneity found in those with dystonia.

Methods

A PubMed search was conducted using the term “neuropathology of dystonia”. The resulting list of references was limited to English-language human neuropathology articles. A total of 20 publications were retrieved and reviewed.

Results

Historically, based on study of acquired forms of dystonia, lesions of the putamen and globus pallidus have been identified as causing dystonia. After the identification of genetic causes of dystonia and the study of limited tissue available from those cases, as well as findings from cases of isolated focal and segmental dystonia, there is evidence that brainstem cholinergic neurons and specific cell populations within the cerebellum also play a role in the pathophysiology of dystonia.

Discussion

Based on limited available brain tissue, there is evidence that the pathophysiology of dystonia may involve a combination of dysfunction within neurons of the brainstem, cerebellum, putamen, and globus pallidus. In order to gain a better understanding of the pathophysiology of dystonia, a prospective, quantitative study in well-phenotyped subjects with different types of genetic and isolated dystonia is required.

Contribution of TMS and rTMS in the Understanding of the Pathophysiology and in the Treatment of Dystonia

Dystonias represent a heterogeneous group of movement disorders responsible for sustained muscle contraction, abnormal postures, and muscle twists. It can affect focal or segmental body parts or be generalized. Primary dystonia is the most common form of dystonia but it can also be secondary to metabolic or structural dysfunction, the consequence of a drug's side-effect or of genetic origin. The pathophysiology is still not elucidated. Based on lesion studies, dystonia has been regarded as a pure motor dysfunction of the basal ganglia loop. However, basal ganglia lesions do not consistently produce dystonia and lesions outside basal ganglia can lead to dystonia; mild sensory abnormalities have been reported in the dystonic limb and imaging studies have shown involvement of multiple other brain regions including the cerebellum and the cerebral motor, premotor and sensorimotor cortices. Transcranial magnetic stimulation (TMS) is a non-invasive technique of brain stimulation with a magnetic field applied over the cortex allowing investigation of cortical excitability. Hyperexcitability of contralateral motor cortex has been suggested to be the trigger of focal dystonia. High or low frequency repetitive TMS (rTMS) can induce excitatory or inhibitory lasting effects beyond the time of stimulation and protocols have been developed having either a positive or a negative effect on cortical excitability and associated with prevention of cell death, γ-aminobutyric acid (GABA) interneurons mediated inhibition and brain-derived neurotrophic factor modulation. rTMS studies as a therapeutic strategy of dystonia have been conducted to modulate the cerebral areas involved in the disease. Especially, when applied on the contralateral (pre)-motor cortex or supplementary motor area of brains of small cohorts of dystonic patients, rTMS has shown a beneficial transient clinical effect in association with restrained motor cortex excitability. TMS is currently a valuable tool to improve our understanding of the pathophysiology of dystonia but large controlled studies using sham stimulation are still necessary to delineate the place of rTMS in the therapeutic strategy of dystonia. In this review, we will focus successively on the use of TMS as a tool to better understand pathophysiology, and the use of rTMS as a therapeutic strategy.

Reduced Number of Pigmented Neurons in the Substantia Nigra of Dystonia Patients? Findings from Extensive Neuropathologic, Immunohistochemistry, and Quantitative Analyses

Background

Dystonias (Dys) represent the third most common movement disorder after essential tremor (ET) and Parkinson's disease (PD). While some pathogenetic mechanisms and genetic causes of Dys have been identified, little is known about their neuropathologic features. Previous neuropathologic studies have reported generically defined neuronal loss in various cerebral regions of Dys brains, mostly in the basal ganglia (BG), and specifically in the substantia nigra (SN). Enlarged pigmented neurons in the SN of Dys patients with and without specific genetic mutations (e.g., GAG deletions in DYT1 dystonia) have also been described. Whether or not Dys brains are associated with decreased numbers or other morphometric changes of specific neuronal types is unknown and has never been addressed with quantitative methodologies.

Methods

Quantitative immunohistochemistry protocols were used to estimate neuronal counts and volumes of nigral pigmented neurons in 13 SN of Dys patients and 13 SN of age-matched control subjects (C).

Results

We observed a significant reduction (∼20%) of pigmented neurons in the SN of Dys compared to C (p<0.01). Neither significant volumetric changes nor evident neurodegenerative signs were observed in the remaining pool of nigral pigmented neurons in Dys brains. These novel quantitative findings were confirmed after exclusion of possible co-occurring SN pathologies including Lewy pathology, tau-neurofibrillary tangles, β-amyloid deposits, ubiquitin (ubiq), and phosphorylated-TAR DNA-binding protein 43 (pTDP43)-positive inclusions.

Discussion

A reduced number of nigral pigmented neurons in the absence of evident neurodegenerative signs in Dys brains could indicate previously unconsidered pathogenetic mechanisms of Dys such as neurodevelopmental defects in the SN.

Mouse models of neurodevelopmental disease of the basal ganglia and associated circuits

This chapter focuses on neurodevelopmental diseases that are tightly linked to abnormal function of the striatum and connected structures. We begin with an overview of three representative diseases in which striatal dysfunction plays a key role--Tourette syndrome and obsessive-compulsive disorder, Rett's syndrome, and primary dystonia. These diseases highlight distinct etiologies that disrupt striatal integrity and function during development, and showcase the varied clinical manifestations of striatal dysfunction. We then review striatal organization and function, including evidence for striatal roles in online motor control/action selection, reinforcement learning, habit formation, and action sequencing. A key barrier to progress has been the relative lack of animal models of these diseases, though recently there has been considerable progress. We review these efforts, including their relative merits providing insight into disease pathogenesis, disease symptomatology, and basal ganglia function.

Primary dystonia: moribund or viable

With increasing understanding of dystonia genetic etiologies and pathophysiology there has been renewed scrutiny and reappraisal of dystonia classification schemes and nomenclature. One important category that includes both clinical and etiologic criteria is primary dystonia. This editorialized review discusses the impact of recent findings on primary dystonia criteria and argues that it remains useful in clinical and research practice. © 2013 Movement Disorder Society.

Pathologic changes in the brain in cervical dystonia pre- and post-mortem - a commentary with a special focus on the cerebellum

In a recent issue of Experimental Neurology, Prudente et al. (2012) investigated the neuropathology of cervical dystonia in six patients. Their most important finding was a patchy loss of cerebellar Purkinje cells in the cerebellum. In this article we discuss their findings in the context of a review including primary and secondary cervical dystonia. An update is given of the current knowledge on structural and functional brain abnormalities in idiopathic cervical dystonia with a special focus on the cerebellum.

Neuropathology of cervical dystonia

The aim of this study was to search for neuropathological changes in postmortem brain tissue of individuals with cervical dystonia (CD). Multiple regions of formalin-preserved brains were collected from patients with CD and controls and examined with an extensive battery of histopathological stains in a two-stage study design. In stage one, 4 CD brains underwent a broad screening neuropathological examination. In stage two, these 4 CD brains were combined with 2 additional CD brains, and the subjective findings were quantified and compared to 16 age-matched controls. The initial subjective neuropathological assessment revealed only two regions with relatively consistent changes. The substantia nigra had frequent ubiquitin-positive intranuclear inclusions known as Marinesco bodies. Additionally, the cerebellum showed patchy loss of Purkinje cells, areas of focal gliosis and torpedo bodies. Other brain regions showed minor or inconsistent changes. In the second stage of the analysis, quantitative studies failed to reveal significant differences in the numbers of Marinesco bodies in CD versus controls, but confirmed a significantly lower Purkinje cell density in CD. Molecular investigations revealed 4 of the CD cases and 2 controls to harbor sequence variants in non-coding regions of THAP1, and these cases had lower Purkinje cell densities regardless of whether they had CD. The findings suggest that subtle neuropathological changes such as lower Purkinje cell density may be found in primary CD when relevant brain regions are investigated with appropriate methods.

Update on the pathology of dystonia

Dystonia is a clinical syndrome with sustained muscle contraction, twisting, and abnormal postures. A number of different genetic forms have been defined, but most cases are sporadic in nature and of uncertain cause. Relatively few cases of dystonia have been studied pathologically. In primary dystonias, where dystonia is the main symptom, most reports describe little or no detectable neuropathology, although changes in brainstem neurons have been described in some cases. Secondary dystonias are associated with degenerative or destructive diseases of the nervous system; the pathology may be located in the basal ganglia, but in some cases the primary pathological changes are found in the cerebellum or cerebellar outflow pathways, suggesting that both regions may be involved in the pathogenesis of dystonic symptoms. Overall the number of well-documented pathological cases available for study is few, and there is an urgent need for additional postmortem studies. This article is part of a Special Issue entitled "Advances in dystonia".

Adult-onset dystonia

Dystonia is defined as involuntary sustained muscle contractions producing twisting or squeezing movements and abnormal postures. The movements can be stereotyped and repetitive and they may vary in speed from rapid to slow; sustained contractions can result in fixed postures. Dystonic disorders are classified into primary and secondary forms. Several types of adult-onset primary dystonia have been identified but all share the characteristic that dystonia (including tremor) is the sole neurologic feature. The forms most commonly seen in neurological practice include cranial dystonia (blepharospasm, oromandibular and lingual dystonia and spasmodic dysphonia), cervical dystonia (also known as spasmodic torticollis) and writer's cramp. These are the disorders that benefit most from botulinum toxin injections. A general characteristic of dystonia is that the movements or postures may occur in relation to specific voluntary actions by the involved muscle groups (such as in writer's cramp). Dystonic contractions may occur in one body segment with movement of another (overflow dystonia). With progression, dystonia often becomes present at rest. Dystonic movements typically worsen with anxiety, heightened emotions, and fatigue, decrease with relaxation, and disappear during sleep. There may be diurnal fluctuations in the dystonia, which manifest as little or no involuntary movement in the morning followed by severe disabling dystonia in the afternoon and evening. Morning improvement (or honeymoon) is seen with several types of dystonia. Patients often discover maneuvers that reduce the dystonia and which involve sensory stimuli such as touching the chin lightly in cervical dystonia. These maneuvers are known as sensory tricks, or gestes antagonistes. This chapter focuses on adult-onset focal dystonias including cranial dystonia, cervical dystonia, and writer's cramp. The chapter begins with a review of the epidemiology of focal dystonias, followed by discussions of each major type of focal dystonia, covering clinical phenomenology, differential genetics, and diagnosis. The chapter concludes with discussions of the pathophysiology, the few pathological cases published of adult-onset focal dystonia and management options, and a a brief look at the future.

The effects of reversible inactivation of the subthalamo-pallidal pathway on the behaviour of naive and hemiparkinsonian monkeys

This study was designed to further investigate the role of the subthalamic nucleus (STN) and globus pallidus internus (GPi) in the pathophysiology of Parkinson's disease. The prevailing theory about the pathophysiology of Parkinson's disease (PD) predicts that there is overactivity of the subthalamo-pallidal pathway. In order to inactivate that pathway, naive and hemiparkinsonian monkeys were locally administered either muscimol (to reversibly inactivate the contralateral STN) or kynurenic acid (to reduce glutamatergic activity in the contralateral GPi). Three naive and 2 hemiparkinsonian monkeys were studied. Intra-carotid MPTP was administered to produce 2 hemiparkinsonian monkeys. Injection sites of muscimol and kynurenic acid in the brain were confirmed electrophysiologically and histologically. Injections of muscimol into the STN in naive and hemiparkinsonian monkeys caused reversible contralateral dystonia, but did not alleviate Parkinsonism. Only one kynurenic acid injection into GPi partially alleviated Parkinsonism. On the basis of the results in this study, aspects of the currently accepted hypothesis of the pathophysiology of PD cannot be confirmed. However, this study reports that the STN has an important role in the production of dystonia. This experimental model of dystonia will prove suitable for further study of both the mechanisms causing dystonia as well as for possible therapeutic approaches to its treatment.

Dystonia associated with pontomesencephalic lesions

Secondary dystonia is well known subsequent to lesions of the basal ganglia or the thalamus. There is evidence that brainstem lesions may also be associated with dystonia, but little is known about pathoanatomical correlations. Here, we report on a series of four patients with acquired dystonia following brainstem lesions. There were no basal ganglia or thalamic lesions. Three patients suffered tegmental pontomesencephalic hemorrhage and one patient diffuse axonal injury secondary to severe craniocerebral trauma. Dystonia developed with a delay of 1 to 14 months, at a mean delay of 6 months. The patients' mean age at onset was 33 years (range 4-56 years). All patients presented with hemidystonia combined with cervical dystonia, and two patients had craniofacial dystonia in addition. Three patients had postural or kinetic tremors. Dystonia was persistent in three patients, and improved gradually in one. There was little response to medical treatment. One patient with hemidystonia combined with cervical dystonia improved after thalamotomy. Overall, the phenomenology of secondary dystonia due to pontomesencephalic lesions is similar to that caused by basal ganglia or thalamic lesions. Structures involved include the pontomesencephalic tegmentum and the superior cerebellar peduncles. Such lesions are often associated with fatal outcome. While delayed occurrence of severe brainstem dystonia appears to be rare, it is possible that mild manifestations of dystonia might be ignored or not be emphasized in the presence of other disabling deficits.

Orofacial movement disorders

This article reviews three poorly recognized yet relatively common presentations of hyperactive orofacial movement disorders: oromandibular dystonia, orofacial dyskinesia, and drug-induced extrapyramidal syndrome reactions. Orofacial movement disorders are often misdiagnosed as temporomandibular disorders, hence understanding these conditions is pertinent for the practitioner treating orofacial pain. Aspects of epidemiology, etiology, pathophysiology, clinical presentation, and diagnosis are discussed along with treatment considerations for these orofacial movement disorders.

Hemidystonia precipitated by acute pontine infarct

Hemidystonia is frequently due to an underlying structural lesion in the basal ganglia and thalamus. It has been suggested that a preserved corticospinal tract may be required for hemidystonia to manifest. We provide the first report of a patient who presented with rapid-onset hemidystonia precipitated by an acute pontine infarct demonstrated on diffusion-weighted magnetic resonance imaging. Acute dysregulation of pallidal efferents to the pedunculopontine and/or pontine afferents to the thalamus may precipitate hemidystonia.

Jaw-opening dystonia (Brueghel's syndrome) associated with cavum septi pellucidi and Verga's ventricle - a case report

Jaw-opening dystonia (oromandibular dystonia with jaw-opening; Brueghel's syndrome) is a rare condition, and only a limited number of cases have been reported in the literature. However, many patients may remain undiscovered or misdiagnosed, like a patient described previously. A case (40-year-old man) of jaw-opening dystonia (oromandibular dystonia with jaw-opening; Brueghel's syndrome) is reported. In this case, brain anomalies, cavum septi pellucidi and Verga's ventricle, were observed on magnetic resonance imaging of the brain. This case and a review of the literature indicate the presence of organic factors in the etiology of Brueghel's syndrome. The etiological relationship of brain anomalies in Bruegel's syndrome is discussed.

Positron emission tomography scanning in essential blepharospasm

PURPOSE

To localize in the brain using positron emission tomography neuroimaging with (18)fluorodeoxyglucose [PET ((18)FDG)] differences in glucose metabolism between patients with essential blepharospasm (EB) and controls.

DESIGN

Prospective case-control study.

METHODS

Positron emission tomography neuroimaging with (18)fluorodeoxyglucose was performed in 11 patients with EB and 11 controls matched for age and gender. Global analysis of images was used to localize differences in glucose metabolism between groups.

RESULTS

Multiple cortical and subcortical abnormalities were observed in EB patients in comparison with controls. Cortical areas with the largest and most significant clusters of increased glucose uptake were the inferior frontal gyri, right posterior cingulate gyrus, left middle occipital gyrus, fusiform gyrus of the right temporal lobe, and left anterior cingulate gyrus. Cortical areas with the largest and most significant clusters of decreased glucose uptake were the inferior frontal gyri, ventral to the area of increased glucose metabolism. Subcortical abnormalities, consisting of increased glucose uptake, involved the right caudate and consisting of decreased glucose uptake, involved the left inferior cerebellar hemisphere and thalamus.

CONCLUSIONS

Global analysis of positron emission tomography neuroimaging with (18)fluorodeoxyglucose neuroimaging in EB patients in comparison with controls demonstrates a pattern of abnormalities involving several cortical and subcortical areas that control blinking, including the inferior frontal lobe, caudate, thalamus, and cerebellum.

Severe generalized dystonia due to primary putaminal degeneration: case report and review of the literature

Putaminal lesions of a variety of etiologies may cause secondary dystonia. We report on a case of primary putaminal degeneration as a cause of severe childhood-onset generalized dystonia and review the literature of the pathology of dystonia. A 44-year-old patient with severe generalized childhood-onset dystonia and macrocephaly underwent neurological evaluation and neuropathological examination. Neurological examination was normal apart from dystonia and signs referable to prior cryothalamotomy. Workup for metabolic and genetic causes of dystonia was negative. Neuroimaging showed severe bilateral putaminal degeneration, which subsequently correlated with the neuropathological findings of gliosis, spongiform degeneration, and cavitation. The substantia nigra pars compacta contained a normal number of neurons but decreased tyrosine hydroxylase immunoreactivity. There were no histopathological markers of other metabolic or degenerative diseases.

Neuroimaging in basal ganglia disorders: perspectives for transcranial ultrasound

Transcranial sonography is a new diagnostic tool, allowing not only the evaluation of cerebral arteries but also the two-dimensional display of the brain parenchyma. In this review we will summarize basics of the application, the ultrasound anatomy of the brain and sonographic findings in some movement disorders. While in normal adults basal ganglia nuclei are hypoechogenic, they are hyperechogenic in certain basal ganglia disorders. In Parkinson's disease, for example, the substantia nigra can be depicted as a distinctly echogenic area. An elevated echogenicity of the lentiform nuclei was noticed in patients with primary adult-onset dystonia. In both disorders the altered echogenicity may arise from higher heavy metal tissue content (i.e. iron in Parkinson's disease and copper in primary dystonia). Our findings converge to the hypothesis that transcranial ultrasound sensitively detects pathological metal accumulation not identified by other neuroimaging techniques (CT and MRI) and therefore provides new insights in the diagnosis of basal ganglia disorders. The implications of these findings for the understanding of the pathogenesis and its usefulness for the early diagnosis of movement disorders are outlined.

Increased tissue copper and manganese content in the lentiform nucleus in primary adult-onset dystonia

We analyzed trace metals in frozen brain tissue of several subcortical nuclei from 3 patients with primary adult-onset dystonia and 10 control subjects. Copper levels were significantly increased in the globus pallidus and putamen of patients with dystonia A slight increase in manganese content was identified in the putamen and thalamus of patients with dystonia. Our findings show for the first time an accumulation of trace metals in the lentiform nuclei in patients with primary dystonia, which may play a pathogenetic role in primary dystonia and may explain recent ultrasound and magnetic resonance imaging findings.

Involuntary movements and abnormal spontaneous EMG activity in syringomyelia and syringobulbia

OBJECTIVE

To describe different types of involuntary movements and abnormal spontaneous electromyographic (EMG) activity in patients with syringomyelia.

BACKGROUND

A comprehensive study on involuntary movements in patients with syringomyelia has not yet been undertaken, to these authors' knowledge.

METHODS

One hundred adult patients with syringomyelia were examined over the last 15 years. Involuntary movements were videotaped and evaluated by two independent observers. Electromyographic recordings were made using bipolar surface electrodes. The H-reflex recovery curve was obtained after stimulation of the median nerve at the elbow and recording from the flexor carpi radialis.

RESULTS

Involuntary movements or abnormal postures were observed in 22 patients. Three patients showed segmental spinal myoclonus, nine minipolymyoclonus, and four propriospinal myoclonus. Five patients had unilateral or bilateral hand postural tremor (8-10 Hz). Focal or segmental dystonia was observed in three patients. Electromyography showed spontaneous bursts of grouped action potentials synchronous in muscles innervated by the same spinal segment, synchronous firing of neurogenic motor unit potentials, or continuous motor unit activity. Increased H-reflex responses to conditioning stimuli were found in patients with spinal myoclonus. Long latency responses were obtained during peripheral nerve stimulation in four patients. Four patients had rigidity and abnormal upper limb posture. Respiratory synkinesis was observed in three patients. One patient developed inverse masticatory muscle activity.

CONCLUSIONS

Patients with syringomyelia showed a wide spectrum of involuntary movements. An increased excitability of spinal motor neurons was probably the basic underlying mechanism.

Dystonia after striatopallidal and thalamic stroke: clinicoradiological correlations and pathophysiological mechanisms

OBJECTIVE

To establish the pathophysiological mechanisms of striatopallidal and thalamic dystonia.

METHODS

Five patients from among 26 who presented (between March 1987 and July 1996) with focal dystonia, segmental dystonia, or hemidystonia caused by a single localised vascular lesion, were selected. Patients with lesions with indefinite boundaries, and diffuse, or multiple, or large brain lesions were excluded. Three dimensional T1 weighted MRI (1.5 tesla) was performed to determine the topography of the lesions. The atlas of Hassler allowed the stereotactic localisation of the lesions to be specified exactly.

RESULTS

Three patients had dystonic spasms associated with striatopallidal lesions and one with a thalamic and striatopallidal lesion. One other patient presented with a myoclonic dystonia related to a thalamic lesion. The striatopallidal lesions were located in the sensorimotor area with a somatotopical distribution. The pure thalamic lesion involved the centromedian nucleus, the sensory nuclei, and the pulvinar whereas the thalamic and striatopallidal lesion was located in the pallidonigral thalamic territory, which receives pallidonigral inputs.

CONCLUSION

The striatopallidal dystonia might be the consequence of the interruption of the cortico-striato-pallido-thalamo-cortical loop induced by lesions located within the sensorimotor part of the striatopallidal complex. By contrast, it is suggested that thalamic dystonia might be caused by lesions located in the centro-median or the ventral intermediate nuclei, outside the pallidonigral territory, but leading also to a dysfunction of the cortico-striato-pallido-thalamo-cortical loop.

Increased activation of frontal areas during arm movement in idiopathic torsion dystonia

Most positron emission tomography (PET) studies of regional cerebral function in idiopathic torsion dystonia (ITD) have failed to show abnormalities, but there have been few studies of the changes in regional cerebral blood flow (rCBF) that occur during movement in dystonia. Using PET, we have studied six patients with familial generalized ITD both at rest and while moving a joystick with the right hand. The patterns of CBF change obtained were compared with those in six age-matched control subjects. In the dystonia group, free selection of movement was associated with relative increases in rCBF above that observed in control subjects in the left premotor area, the supplementary motor area (SMA), the anterior cingulate cortex, and the left dorsolateral prefrontal area. Subcortical increases were observed within the cerebellum and the putamen. There was a relative decrease in flow through the contralateral primary sensorimotor cortex. These findings contrast with those reported in patients with Parkinson's disease undertaking the same task in which the activity in the SMA and putamen was decreased. We suggest that arm dystonia in ITD is associated with overactivity of the premotor areas, including the SMA, and that this results from release of the thalamus from the normal inhibitory influence of the globus pallidus internal segment. Other abnormalities of basal ganglia control of brain stem centers may be involved in axial dystonia.

Asymmetric predominantly ipsilateral blepharospasm and contralateral parkinsonism in an elderly patient with a right mesencephalic cyst

A 66-year-old woman presented with a 3-year history of predominantly right-sided blepharospasm and a 1-year history of progressive predominantly left-sided hemiparkinsonism manifested by a left upper extremity resting tremor and left-sided bradykinesia. Magnetic resonance imaging of the brain revealed a large right mesencephalic cyst with mass effect. Positron emission tomography revealed bilateral striatal hypometabolism consistent with nigrostriatal dopaminergic dysfunction. The association of predominantly ipsilateral blepharospasm and predominantly contralateral hemiparkinsonism is very rare, and its association with a posterior fossa space-occupying lesion has been reported only once. This is the second report of such an association and the first description of adult-onset symptomatology.

Dystonia and dyskinesia

Dystonia is defined as a syndrome of sustained muscle contractions, frequently causing twisting and repetitive movements, or abnormal postures. Tardive dyskinesia (TD), estimated to occur in 30% of patients treated with neuroleptics, encompasses a broad spectrum of hyperkinesias associated with exposure to these drugs. Dystonia is one of the most common expressions of tardive dyskinesia. This article aims to provide an overview of classification, phenomenology, epidemiology, genetics, pathophysiology, neuropsychologic aspects, and treatment of these two conditions.

Mosaic pattern of gliosis in the neostriatum of a North American man with craniocervical dystonia and parkinsonism

We present the case of a 51-year-old patient with a 31-year history of psychiatric symptoms, craniocervical dystonia, bulbar dysfunction, and parkinsonism. His dystonic movements included blepharospasm, jaw opening and lingual dystonia, and spasmodic retrocollis. Psychiatric symptoms included psychosis and depression, with onset years before the movement disorder. After his death by aspiration, examination of his brain revealed abnormalities limited to the neostriatum. Staining of brain sections, including Holzer, glial fibrillary acidic protein, and immunohistochemical stain for calbindin D28k, revealed the presence of a mosaic pattern of gliosis with neuronal loss (sparing large neurons) within this region. The islands of tissue between stands of gliosis had a normal appearance. This patient represents only the fourth case (and first North American born) with a mosaic pattern of gliosis in the neostriatum. The clinical and pathologic features were similar in all four cases except that our patient was the first with prominent psychiatric symptoms and a more stable, less progressive course. Mosaicism has been described in the X-linked Filipino disorder Lubag. Occurrence in non-Filipino patients, such as ours, suggest that either Lubag can develop in non-Filipino families or that mosaicism is a nonspecific pathologic finding in some patients with idiopathic dystonia. Finally, our case reports the notion that craniocervical dystonia may result from neostriatal dysfunction.

Cervical dystonia associated with tumors of the posterior fossa

Cervical dystonia was associated with posterior fossa tumors in three patients. The onset of dystonia paralleled the appearance of other focal neurologic signs. All patients had extraaxial tumors located in the cerebellopontine angle that were removed via suboccipital approaches. The tumors were identified as schwannomas arising from the glossopharyngeal nerve and from the vagus/accessory nerves; and a meningioma. Postoperatively, the cervical dystonia improved markedly during a period of 8 years in one patient, and it remitted completely within 1 year in another patient. In the third patient, cervical dystonia persisted. The combination of the clinical findings and the temporal relationship of their appearance suggest a causal association between the posterior fossa tumors and cervical dystonia in three cases. Possible pathogenic mechanisms are reviewed.

Comparison of transcranial sonography, magnetic resonance imaging, and single photon emission computed tomography findings in idiopathic spasmodic torticollis

Various lines of evidence suggest that the basal ganglia and thalamus are involved in the pathogenesis of idiopathic dystonia, but unfortunately neuroradiological and pathological data are sparse and controversial. In this study, we have examined 10 patients with spasmodic torticollis by neuroimaging techniques, including transcranial sonography (TS; n = 10), conventional (n = 10) and diffusion-weighted (n = 5) magnetic resonance imaging (MRI), and single photon emission computed tomography (SPECT; n = 10), employing [123I]iodobenzamide (IBZM) as a ligand with a high affinity to the D2 receptor. In seven patients, TS showed small hyperechogenic lesions in the medial segments of the lentiform nucleus contralateral to the side of head deviation. In accordance with the site of TS abnormalities, diffusion-weighted MRI displayed a hyperintense lesion in only one patient, while standard MRI of this area was normal in all patients. SPECT revealed a slight but statistically nonsignificant reduction of IBZM tracer uptake in an area corresponding to the dorsal portions of the striatum in 9 of the 10 patients. TS findings support the hypothesis that structural alternations of the pallidothalamic circuit contralateral to the side of head deviation are involved in the pathogenesis of idiopathic spasmodic torticollis. TS may be more sensitive in detecting basal ganglia alterations than MRI.

Saccadic eye movements in idiopathic blepharospasm

Visually guided saccades, memory-contingent saccades, and antisaccades were studied with an infra-red reflection technique in 12 patients with idiopathic blepharospasm and in controls. Latencies of the three kinds of saccades were prolonged. Peak velocities and gains did not differ. Our results indicate an initiation defect in the saccadic system, which may be localized in the caudate nucleus.

SPECT abnormalities in generalized dystonia

A patient with severe, generalized dystonia and 6 age range-matched controls were studied with the regional cerebral blood flow tracer technetium-99m hexamethylpropyleneamine oxime by single-photon emission computed tomography to test the hypothesis that cerebellar function is abnormal in dystonia. Analysis was performed by drawing regions of interest around the caudate head nuclei, hemithalami, deep cerebellar nuclei, and cerebellar hemicortices. The counts in each region of interest were normalized to whole brain cerebral blood flow in an identical manner for each subject. The dystonic patient had a difference in regional cerebral blood flow between the right and left deep cerebellar nuclei, increased regional cerebral blood flow in subcortical motor structures, and an abnormal relationship between right cerebellar cortical and right deep cerebellar nuclear regional cerebral blood flow. The findings in this patient provide evidence that the cerebellum may play a role in the pathophysiology of motor signs in some patients with dystonia.

Movement disorders following lesions of the thalamus or subthalamic region

Reports of 62 cases with a movement disorder associated with a focal lesion in the thalamus and/or subthalamic region were analyzed. Thirty-three cases had a lesion confined to the thalamus. Sixteen cases had a thalamic lesion extending into the subthalamic region and/or midbrain. Thirteen cases had a lesion in the subthalamic region or a subthalamic lesion extending into the midbrain. Nineteen cases with dystonia, 18 with asterixis, 17 with ballism-chorea, three with paroxysmal dystonia, and five with clonic or myorhythmic movements have been described. No case with isolated tremor has been described. In 53 cases with unilateral thalamic or subthalamic lesions, all but one with bilateral blepharospasm (associated with right posterior thalamic, pontomesencephalic, and bilateral cerebellar lesions) had dyskinesias in the limbs contralateral to the lesion. The other nine cases had bilateral paramedian thalamic lesions; seven developed bilateral dyskinesias, and the remaining two had unilateral dyskinesias. Regarding the 19 patients with dystonia, the two with bilateral blepharospasm had thalamic and upper brainstem lesions, and one with hemidystonia and torticollis had a subthalamic lesion. The other 16 patients all had a unilateral thalamic lesion with contralateral dystonia (10 hemidystonia, five focal dystonia affecting a hand and/or and one segmental dystonia involving face, arm, and hand). The exact location of the thalamic lesion was mentioned in 10 cases; the posterior or posterolateral thalamus was involved in six and the paramedian thalamus in four. These areas are more posterior or medial to the ventrolateral and ventroanterior thalamic nuclei, which receive pallido-thalamic and nigro-thalamic afferents. Two cases developed dystonia immediately after thalamotomy, and one case developed it 4 days after head trauma. The others initially had a hemiplegia and developed dystonia 1-9 months after the acute insult. Fifteen of the 17 patients with chorea had a unilateral lesion in the subthalamic nucleus or subthalamic region (eight due to infarcts, one to hemorrhage, five to mass lesions, and one to multiple sclerosis). All had contralateral hemichorea or hemiballism. One other case had bilateral chorea of the hands and tongue due to paramedian thalamic infarction. Another case with generalized chorea and thalamic atrophy was complicated by stereotaxic surgery. Thirteen of the 18 cases with asterixis had lesions confined to the thalamus. Eight were associated with thalamotomy, and five others had a stroke (four infarction and one hemorrhage) affecting the contralateral thalamus.(ABSTRACT TRUNCATED AT 400 WORDS)

Eyelid motor abnormalities in progressive supranuclear palsy

Eyelid motor abnormalities found in progressive supranuclear palsy are reviewed. Electrophysiological correlates of blepharospasm, levator inhibition (blepharokolysis) and supranuclear paralysis of lid closure are presented. Disorders of eyelid motility are not uncommon in progressive supranuclear palsy (PSP). They may be found in about one third of patients with this syndrome (Jackson et al., 1983; Golbe et al., 1989). This is not surprising since ocular and eyelid movements are highly coordinated, mainly in the vertical plane (Gordon, 1951; Kennard and Smith, 1963; Kennard and Glaser, 1964), and a supranuclear ophthalmoplegia with down gaze impairment is a cardinal feature of PSP (Steele et al., 1964). The spectrum of eyelid motor disorders described in PSP includes blinking abnormalities, lid retraction, blepharospasm, levator inhibition and supranuclear palsy of eye closure.

Orofacial dystonia and rest tremor in a patient with normal brain pathology

We report a patient with cranial dystonia who also had rest tremor of one arm and who developed drug-induced parkinsonism on treatment. The patient's brain was normal on autopsy. We also review the findings in the few reported cases of cranial dystonia with pathology.

Neuropathology of lubag (x-linked dystonia parkinsonism)

Lubag is an x-linked recessive dystonia parkinsonism that affects Filipino men originating principally from the Panay Island. Linkage analysis has confirmed the mode of inheritance and localized the disease gene to the proximal long arm of the x-chromosome. We studied the brain of a 34 year old Filipino man affected with lubag. He developed truncal dystonia at age 30, which subsequently generalized. With disease progression, he also presented with parkinsonism including, rigidity, bradykinesia, and impaired balance. His symptoms were largely unaffected by medication and, at age 34, he underwent a right cryothalamotomy. He died suddenly 2 days after the procedure. The principal neuropathological findings were neuronal loss and a multifocal mosaic pattern of astrocytosis restricted to the caudate and lateral putamen. Similar findings have been reported in two other men with dystonia--one Filipino and the other non-Filipino. The similar pathology of the two Filipino men suggests that this is the pathology of lubag. Recognition of this pathology in a non-Filipino man suggests that the mutation causing lubag may not be restricted to the Filipino population.

Basal ganglia infarction as a possible cause of cervical dystonia

Cervical dystonia (CD) is usually an idiopathic disorder that results in abnormal movements and painful postures of the neck. Although symptomatic CD caused by focal CNS lesions has been described in the literature, it is an exceedingly rare phenomenon. We report two women who had an abrupt onset of CD at the ages of 39 and 68 years. Each patient had rotation of the head to the right and was found to have a lacunar infarction in the left putamen on magnetic resonance imaging scan. The abrupt onset of symptoms and appropriate location and laterality of the cerebral lesions suggest an etiologic link between the infarctions and the patients' CD. These cases are the first reports of CD possibly caused by basal ganglia infarction.

Severe generalised dystonia associated with a mosaic pattern of striatal gliosis

A mosaic pattern of striatal pathology is described in a male who developed severe generalised dystonia from the age of 10 years, and died at the age of 18 years. There was no family history of dystonia, and extensive investigations during his life failed to identify a cause for the dystonia. The caudate nucleus and putamen showed a network of cell loss and gliosis surrounding islands of preserved striatum. Dorsal parts showed confluent gliosis, and ventral parts were spared. The pattern suggested a correlation with patch-matrix organisation, but there was no correlation with the distribution of calbindin immunoreactive cells, which are present in the matrix of the classical striosome-matrix organisation. The pathological findings were unlike those in status marmoratus, perinatal hypoxia-ischaemia, Huntington's disease, and neuroacanthocytosis, but similar to those reported in a 44-year-old man with predominantly cranial dystonia.

Motor inhibition from the brainstem is normal in torsion dystonia during REM sleep

The maintenance of axial atonia during REM sleep was monitored in 14 patients with primary torsion dystonia, 10 patients with secondary torsion dystonia, and 10 normal subjects using submental EMG and video EEG telemetry. The excitability of the corticospinal tract during REM sleep was also assessed using scalp magnetic stimulation in seven patients and three controls. During REM sleep dystonic patients had well maintained atonia evidenced by infrequent bursts of submental activity, no episodes of complex semi-purposeful behaviour and reduced motor responses to magnetic stimulation. These findings suggest that the inhibitory centres in the region of the locus coeruleus and their descending pathways to the spinal alpha motor neurons are intact in torsion dystonia.

Saccadic eye movements in essential blepharospasm

To provide evidence of an organic pathology for essential (idiopathic) blepharospasm, reflex saccadic eye movements in response to randomly stepped visual targets were assessed in seven affected patients and seven age-matched controls using the magnetic scleral search coil technique. The results indicate a significant prolongation in latency and a reduction in gain of horizontal saccades, and an increase in latency and reduction of peak velocity of large downward saccades. These findings suggest an organic component to the aetiology of blepharospasm, the pathology of which also appears to involve the oculomotor system. The pattern of the oculomotor disorder does not allow specific localisation but is consistent with the underlying pathology being localised in the basal ganglia.

Spasmodic torticollis due to a midbrain lesion in a case of multiple sclerosis

A case of multiple sclerosis is described in which spasmodic torticollis occurred abruptly and abated after 1 year. Magnetic resonance imaging (MRI) demonstrated a lesion in the mesencephalon. Other symptoms and physical signs that developed at the same time as the spasmodic torticollis were compatible with the lesion that had not been present on MRI 18 months previously. There are very few reports of spasmodic torticollis due to an identified focal lesion; there is evidence from experimental work on animals that midbrain lesions may cause spasmodic torticollis but there has been no previous human example.

Eyelid movement abnormalities in progressive supranuclear palsy

We systematically videotaped eyelid movements in a community-based series of 38 patients with progressive supranuclear palsy (PSP). Ten patients (26%) had blepharospasm, "apraxia" of lid opening and/or "apraxia" of lid closing. These patients as a group had more severe upgaze paresis but no greater disease duration than the patients without supranuclear lid dysfunction. Patients used a variety of synkinetic movements to overcome lid-movement abnormalities. One patient displayed "slow blinks," a phenomenon not previously described in PSP. Blink rate in PSP, 3.0/min, was markedly lower than that in patients with Parkinson's disease (PD), 12.5/min, and patients with PSP but not PD increased their blink rate during command versional eye movements.