Pure hemidystonia with basal ganglion abnormalities on positron emission tomography

Paroxysmal Kinesigenic Dyskinesia Symptoms Markedly Reduced with Parenteral Vitamins and Minerals: A Case Report

INTRODUCTION

Paroxysmal kinesigenic dyskinesia (PKD) is a rare movement disorder triggered by sudden voluntary movements. The disorder involves attacks of chorea, which resolve within minutes, that may occur frequently throughout the day.

CASE PRESENTATION

A 61-year-old woman presented to the clinic with a 13-year history of PKD first diagnosed in 2002. This patient had frequent episodic attacks of PKD, which were so severe she had difficulty with ambulation and other activities of daily living. The case was complicated by an additional diagnosis of chronic fatigue syndrome. She refused antiseizure medication because of concerns about it exacerbating her fatigue. In the office, she was given weekly parenteral doses of vitamins and minerals, which almost completely eliminated her symptoms between treatments and allowed her to return to activities of daily living.

DISCUSSION

Genetic testing, not related to her PKD diagnosis, revealed several mutations that could offer an explanation for the apparent efficacy of parenteral therapy in this patient.

Facilitation of handwriting in a case of dystonic writer's cramp: a kinesiological EMG study

Dyskinetic disorders can affect fine manual motor skills, particularly handwriting. We have developed a one-finger device to aid handwriting. This paper reports a case in which dystonic posturing has been prevented with the simplification of the handwriting motor task. Additional kinesiological EMG recordings show a significant alteration in the pattern and quantity of electrical muscle signals using this device.

The Dystonias

Dystonia is a difficult problem for both the clinician and the scientist. It is sufficiently common to be seen by almost all physicians, yet uncommon enough to prevent any physician from gaining broad experience in its diagnosis and treatment. Each case represents a difficult challenge even to the specialist. The basic scientist is faced with investigating a disorder that is without relevant animal models and which is so rare that obtaining suitable tissue for study is a major obstacle. Dystonia may be idiopathic, or associated with lesions from many sources, including a variety of rare diseases. If idiopathic, it may be genetically transmitted or sporadic. If genetically transmitted, it may be generalized or focal, with symptoms varying in different members of the same family. It may be refractory to treatment, or it may respond to any one of a number of individual drugs that have very different mechanisms of action. For idiopathic dystonias, no clear method of genetic transmission has been established and no consistent pathology identified.

Movement disorders secondary to craniocerebral trauma

Over the past few decades it has been recognized that traumatic brain injury may result in various movement disorders. In survivors of severe head injury, post-traumatic movement disorders were reported in about 20%, and they persisted in about 10% of patients. The most frequent persisting movement disorder in this population is kinetic cerebellar outflow tremor in about 9%, followed by dystonia in about 4%. While tremor is associated most frequently with cerebellar or mesencephalic lesions, patients with dystonia frequently have basal ganglia or thalamic lesions. Moderate or mild traumatic brain injury only rarely causes persistent post-traumatic movement disorders. It appears that the frequency of post-traumatic movement disorders overall has been declining which most likely is secondary to improved treatment of brain injury. In patients with disabling post-traumatic movement disorders which are refractory to medical treatment, stereotactic neurosurgery can provide long-lasting benefit. While in the past the primary option for severe kinetic tremor was thalamotomy and for dystonia thalamotomy or pallidotomy, today deep brain stimulation has become the preferred treatment. Parkinsonism is a rare consequence of single head injury, but repeated head injury such as seen in boxing can result in chronic encephalopathy with parkinsonian features. While there is still controversy whether or not head injury is a risk factor for the development of Parkinson's disease, recent studies indicate that genetic susceptibility might be relevant.

Successful control with carbamazepine of family with paroxysmal kinesigenic dyskinesia of PRRT2 mutation

Paroxysmal kinesigenic dyskinesia (PKD), a rare paroxysmal movement disorder often misdiagnosed as epilepsy, is characterized by recurrent, brief dyskinesia attacks triggered by sudden voluntary movement. Pathophysiological mechanism of PKD remains not well understood. Ion channelopathy has been suggested, since the disease responds well to ion channel blockers. Mutations in proline-rich transmembrane protein 2 (PRRT2) were recently identified in patients with familial PKD. To extend these genetic reports, we studied a family with clinical manifestations of familial PKD responding well to low dose carbamazepine. Therapeutic dose ranged from 1.5 to 2.0 mg/ kg/day, below that in seizure control. One insertion mutation c.649_650insC (p.P217fsX7) was identified in three patients of the family. This study avers PRRT2’s high sensitivity for PKD phenotype. Identification of genes underlying pathogenesis will enhance diagnosis and treatment. Function of PRRT2 and its role in PKD warrant further investigation.

Nonprimary dystonias

Dystonias can be classified as primary or secondary, as dystonia-plus syndromes, and as heredodegenerative dystonias. Their prevalence is difficult to determine. In our experience 80-90% of all dystonias are primary. About 20-30% of those have a genetic background; 10-20% are secondary, with tardive dystonia and dystonia in cerebral palsy being the most common forms. If dystonia in spastic conditions is accepted as secondary dystonia, this is the most common form of all dystonia. In primary dystonias, the dystonic movements are the only symptoms. In secondary dystonias, dystonic movements result from exogenous processes directly or indirectly affecting brain parenchyma. They may be caused by focal and diffuse brain damage, drugs, chemical agents, physical interactions with the central nervous system, and indirect central nervous system effects. Dystonia-plus syndromes describe brain parenchyma processes producing predominantly dystonia together with other movement disorders. They include dopa-responsive dystonia and myoclonus-dystonia. Heredodegenerative dystonias are dystonic movements occurring in the context of other heredodegenerative disorders. They may be caused by impaired energy metabolism, impaired systemic metabolism, storage of noxious substances, oligonucleotid repeats and other processes. Pseudodystonias mimic dystonia and include psychogenic dystonia and various orthopedic, ophthalmologic, vestibular, and traumatic conditions. Unusual manifestations, unusual age of onset, suspect family history, suspect medical history, and additional signs may indicate nonprimary dystonia. If they are suspected, etiological clarification becomes necessary. Unfortunately, potential etiologies are legion. Diagnostic algorithms can be helpful. Treatment of nonprimary dystonias, with few exceptions, does not differ from treatment of primary dystonias. The most effective treatment for focal and segmental dystonias is local botulinum toxin injections. Deep brain stimulation of the globus pallidus internus is effective for generalized dystonia. Antidystonic drugs, including anticholinergics, tetrabenazine, clozapine, and gamma-aminobutyric acid receptor agonists, are less effective and often produce adverse effects. Dopamine is extremely effective in dopa-responsive dystonia. The Bertrand procedure can be effective in cervical dystonia. Other peripheral surgery, including myotomy, myectomy, neurotomy, rhizotomy, ramizectomy, and accessory nerve neurolysis, has largely been abandoned. Central surgery other than deep brain stimulation is obsolete. Adjuvant therapies, including orthoses, physiotherapy, ergotherapy, behavioral therapy, social support, and support groups, may be helpful. Analgesics should also be considered where appropriate.

Task-specific dystonias: a review

Task-specific dystonias are primary focal dystonias characterized by excessive muscle contractions producing abnormal postures during selective motor activities that often involve highly skilled, repetitive movements. Historically these peculiar postures were considered psychogenic but have now been classified as forms of dystonia. Writer's cramp is the most commonly identified task-specific dystonia and has features typical of this group of disorders. Symptoms may begin with lack of dexterity during performance of a specific motor task with increasingly abnormal posturing of the involved body part as motor activity continues. Initially, the dystonia may manifest only during the performance of the inciting task, but as the condition progresses it may also occur during other activities or even at rest. Neurological exam is usually unremarkable except for the dystonia-related abnormalities. Although the precise pathophysiology remains unclear, increasing evidence suggests reduced inhibition at different levels of the sensorimotor system. Symptomatic treatment options include oral medications, botulinum toxin injections, neurosurgical procedures, and adaptive strategies. Prognosis may vary depending upon body part involved and specific type of task affected. Further research may reveal new insights into the etiology, pathophysiology, natural history, and improved treatment of these conditions.

Is dystonic posturing during temporal lobe epileptic seizures the expression of an endogenous anticonvulsant system?

In temporal lobe epilepsy (TLE) seizures, tonic or clonic motor behaviors (TCB) are commonly associated with automatisms, versions, and vocalizations, and frequently occur during secondary generalization. Dystonias are a common finding and appear to be associated with automatisms and head deviation, but have never been directly linked to generalized tonic or clonic behaviors. The objective of the present study was to assess whether dystonias and TCB are coupled in the same seizure or are associated in an antagonistic and exclusive pattern. Ninety-one seizures in 55 patients with TLE due to mesial temporal sclerosis were analyzed. Only patients with postsurgical seizure outcome of Engel class I or II were included. Presence or absence of dystonia and secondary generalization was recorded. Occurrence of dystonia and occurrence of bilateral tonic or clonic behaviors were negatively correlated. Dystonia and TCB may be implicated in exclusive, non-coincidental, or even antagonistic effects or phenomena in TLE seizures. A neural network related to the expression of one behavioral response (e.g., basal ganglia activation and dystonia) might theoretically "displace" brain activation or disrupt the synchronism of another network implicated in pathological circuit reverberation and seizure expression. The involvement of basal ganglia in the blockade of convulsive seizures has long been observed in animal models. The question is: Do dystonia and underlying basal ganglia activation represent an attempt of the brain to block imminent secondary generalization?

Sensory stimulation accelerates dopamine release in the basal ganglia

We report herein the modulation of dopamine release in the basal ganglia during peripheral electrical stimulation in animals. The endogenous dopamine release during electrical stimulation was measured in anesthetized cats by positron emission tomography (PET) using the D2 receptor agonist [11C]-raclopride. Binding potential (BP) parametric maps were calculated using a simplified reference region model. The regional dopamine release evoked by electrical stimulation was estimated both by region of interest (ROI) analysis and statistical parametric mapping (SPM 99). Both ROI analysis and statistical parametric mapping showed significant release of endogenous dopamine in the nucleus accumbens and the striatum contralateral to the stimulated side as compared to the resting condition as well as the ipsilateral side. Accordingly, we suggest that the activity of the dopaminergic neurons in the midbrain projecting to the nucleus accumbens and the striatum is modulated by the input from the afferent nerves. This provides an in vivo evidence for the importance of the basal ganglia in the processing of peripheral information required for normal movement. This may also explain the clinically observed sensory system abnormalities in patients with movement disorders.

The role of positron emission tomography imaging in movement disorders

PET imaging provides the means to study neurochemical, hemodynamic, or metabolic processes that underlie movement disorders in vivo. Because the extent of presynaptic nigrostriatal dopaminergic denervation can be quantified in PD even at an early or preclinical stage of the disease, PET imaging may allow the selection of at-risk subjects for neuroprotective intervention trials. These techniques may also provide markers to follow progression of disease or evaluate the effects of neurorestorative interventions in patients who have more advanced disease. PET is expected to play an increasing role in the selection of patients who have PD for deep brain stimulation. Dopaminergic studies may have a limited clinical role in the diagnosis of patients who have symptoms that suggestive of PD yet do not respond to typical dopaminergic drugs, such as patients who have vascular parkinsonism or ET with mild resting tremor who may have normal dopaminergic innervation. The differential diagnosis between PD and multiple system atrophy, progressive supranuclear palsy, or corticobasal degeneration is not yet clearly established by PET, but combined pre- and postsynaptic dopaminergic imaging may be able to distinguish early idiopathic PD from atypical parkinsonian disorders, in general. Huntington's chorea is characterized by more prominent striatal dopamine receptor loss, whereas nigrostriatal denervation is present to a lesser degree. Patients who have TS may have enhanced synaptic dopamine release in the putamen. Functional imaging studies have generally failed to demonstrate nigrostriatal denervation in essential tremor or idiopathic dystonia. Studies have shown striatal dopamine receptor loss in selected subtypes of dystonic patients. In conclusion, it is expected that PET will help us to better understand the pathophysiology of movement disorders, increase the diagnostic accuracy, allow preclinical diagnosis, monitor disease progression, and evaluate the efficacy of therapeutic agents. Pharmacologic radioligand displacement studies and the development of new nondopaminergic ligands may further aid in the unraveling of cerebral mechanisms that underlie movement disorders.

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.

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.

Drug-induced Pisa syndrome (pleurothotonus): epidemiology and management

Long-term administration of antipsychotics occasionally produces persistent dystonia of the trunk, a disorder known as Pisa syndrome (or pleurothotonus). The development of Pisa syndrome is most commonly associated with prolonged treatment with antipsychotics; however, it has also been reported, although less frequently, in patients who are receiving other medications (such as cholinesterase inhibitors and antiemetics), in those not receiving medication (idiopathic Pisa syndrome) and in those with neurodegenerative disorders. Drug-induced Pisa syndrome predominantly develops in females and in older patients with organic brain changes. It sometimes occurs after the addition of another antipsychotic to an established regimen of antipsychotics or insidiously arises in antipsychotic-treated patients for no apparent reason. The condition generally disappears after antipsychotic drugs are discontinued. Although a pharmacological therapy for drug-induced Pisa syndrome has not been established, we have reported that anticholinergic drugs are effective in about 40% of patients who have episodes of Pisa syndrome with the remaining patients responding to the withdrawal or reduction of daily doses of antipsychotic drugs. The characteristics of its development and prognosis indicate that drug-induced Pisa syndrome consists of two types of dystonia. Some patients develop clinical features of acute dystonia, whereas others develop symptoms similar to tardive dystonia. Like that of tardive dystonia, Pisa syndrome responds better than tardive dyskinesia to a relatively high daily dose of an anticholinergic. However, the significant improvement caused by the withdrawal of antipsychotic drugs in Pisa syndrome differentiates it from tardive dystonia. Thus, Pisa syndrome including these features is considered to be an atypical type of tardive dystonia. These clinical characteristics suggest that the underlying pathophysiology of drug-induced Pisa syndrome is complex. A dopaminergic-cholinergic imbalance, or serotonergic or noradrenergic dysfunction, may be implicated. Asymmetric brain functions or neural transmission may also be considered as underlying mechanisms of the development of Pisa syndrome that is resistant to anticholinergic drugs. Idiopathic Pisa syndrome is characterised by an adult-onset, segmental truncal dystonia in patients with no previous exposure to antipsychotics. It occurs rarely but shows a complete resolution with high doses of anticholinergic drugs.

[Clinico-pathomorphologic correlations in patients with symptomatic dystonias]

Symptomatic dystonia can be the result of various metabolic, degenerative diseases, the consumption of certain medications or exposure to toxic agents. However, only symptomatic dystonia with focal structural lesion provides a significant "window" for, at least indirect, perception of aetiopathogenesis and pathomorphological substratum of idiopathic dystonia. Our study included 57 patients with symptomatic dystonia, which as a base had focal or multifocal lesions, of whom 7 patients had generalized dystonia, 18 hemidystonia, 6 segmental dystonia, 7 torticollis, 6 blepharospasm, 7 hand dystonia, 3 spasmodic dysphonia, and 3 had oromandibular dystonia. Stroke was highly statistically the most frequent cause of structural lesions (33/57 or 58%). Relevant pathomorphological changes were present in 50/57 (88%) patients, of whom 25 (50%) had lesion in the lenticular nucleus (including individual damage of the putamen and globus pallidus), 12/50 (24%) had damage of the thalamus and 6/50 (12%) had damage of the brainstem. Generalized dystonia was most frequently associated with bilateral lesion of the putamen, hemidystonia with lesion of contralateral putamen, torticollis with damage of the caudate nucleus, hand dystonia with lesion of the thalamus and blepharospasm with lesion of the upper brainstem.

Head injury and posttraumatic movement disorders

WE REVIEW THE phenomenology, pathophysiology, pathological anatomy, and therapy of posttraumatic movement disorders with special emphasis on neurosurgical treatment options. We also explore possible links between craniocerebral trauma and parkinsonism. The cause-effect relationship between head injury and subsequent movement disorder is not fully appreciated. This may be related partially to the delayed appearance of the movement disorder. Movement disorders after severe head injury have been reported in 13 to 66% of patients. Although movement disorders after mild or moderate head injury are frequently transient and, in general, do not result in additional disability, kinetic tremors and dystonia may be a source of marked disability in survivors of severe head injury. Functional stereotactic surgery provides long-term symptomatic and functional benefits in the majority of patients. Thalamic radiofrequency lesioning, although beneficial in some patients, frequently is associated with side effects such as increased dysarthria or gait disturbance, particularly in patients with kinetic tremor secondary to diffuse axonal injury. Deep brain stimulation is used increasingly as an option in such patients. It remains unclear whether pallidal or thalamic targets are more beneficial for treatment of posttraumatic dystonia. Trauma to the central nervous system is an important causative factor in a variety of movement disorders. The mediation of the effects of trauma and the pathophysiology of the development of posttraumatic movement disorders require further study. Functional stereotactic surgery should be considered in patients with disabling movement disorders refractory to medical treatment.

The natural history and treatment of acquired hemidystonia: report of 33 cases and review of the literature

OBJECTIVE

To evaluate the natural history and response to treatment in hemidystonia.

METHODS

190 Cases of hemidystonia were identified; 33 patients in this series and 157 from the world literature. Data was collected on aetiology, age of onset, latency, lesion location, and response to treatment.

RESULTS

The most common aetiologies of hemidystonia were stroke, trauma, and perinatal injury. Mean age of onset was 20 years in this series and 25.7 years in the literature. The average latency from insult to dystonia was 4.1 years in this series and 2.8 years in the literature, with the longest latencies occurring after perinatal injury. Basal ganglia lesions were identified in 48% of cases in this series and 60% of the cases in the literature, most commonly involving the putamen. Patients experienced benefit from medical therapy in only 26% of medication trials in this series and in only 35% of trials in the literature. In the patients reported here, the benzodiazepines clonazepam and diazepam were the most effective medications with 50% of trials resulting in at least some benefit. In the literature, anticholinergic drugs were most effective with 41% of trials resulting in benefit. Surgery was successful in five of six cases in this series and in 22 of 23 cases in the literature. However, in 12 cases, results were transient.

CONCLUSIONS

The most common cause of hemidystonia is stroke, with the lesion most commonly involving the basal ganglia. Hemidystonia responds poorly to most medical therapies, but some patients may benefit from treatment with benzodiazepines or anticholinergic drugs. Surgical therapy may be successful but benefit is often transient.

Paroxysmal dystonic choreoathetosis: clinical features and investigation of pathophysiology in a large family

Paroxysmal dystonic choreoathetosis (PDC) is an unusual hyperkinetic movement disorder characterized by attacks of chorea, dystonia, and ballism with onset in childhood. We report a large British family with dominantly inherited PDC linked to chromosome 2q and describe the clinical features in 20 affected family members. Attacks were precipitated by a variety of factors, including caffeine, alcohol, or emotion, and could be relieved by short periods of sleep in most subjects. The clinical features in the family are compared with those of 11 other PDC families in the literature and a core phenotype for PDC suggested. CSF monoamine metabolites measured at baseline and during an attack in one subject were found to increase during the attack. Magnetic resonance spectroscopy of brain and basal ganglia performed both during and between attacks was normal. Positron emission tomography using the D2 receptor ligand, 11C-raclopride, showed no abnormalities.

Ictal SPECT in paroxysmal non-kinesigenic dyskinesia. Case report and review of the literature

Purpose: Paroxysmal non-kinesigenic dyskinesia (PNKD) should be included in the list of differential diagnosis in patients with refractory epilepsy. Although the pathophysiological mechanisms that underlie this disorder remain controversial, it is now accepted that the basal ganglia are the anatomical substrate responsible for it.Material and methods: We report a 16-year-old mentally retarded male with PNKD admitted for video-EEG monitoring and ictal SPECT, which showed hyperperfusion on the right caudate and thalamus.Conclusion: This case supports more evidence for the involvement of the caudate nucleus and thalamus in the mechanisms responsible for the production of PNKD.

Decreased [18F]spiperone binding in putamen in idiopathic focal dystonia

In this study we have investigated the pathophysiology of two idiopathic focal dystonias: hand cramp with excessive cocontractions of agonist and antagonist hand or forearm muscles during specific tasks, such as writing, and facial dystonia manifested by involuntary eyelid spasms (blepharospasm) and lower facial and jaw spasms (oromandibular dystonia). We used positron emission tomography (PET) to measure the in vivo binding of the dopaminergic radioligand [18F]spiperone in putamen in 21 patients with these two focal dystonias and compared the findings with those from 13 normals. We measured regional cerebral blood flow and blood volume in each subject as well as the radiolabeled metabolites of [18F]spiperone in arterial blood. A stereotactic method of localization, independent of the appearance of the images, was used to identify the putamen in all of the PET images. We analyzed the PET and arterial blood data with a validated nonsteady-state tracer kinetic model representing the in vivo behavior of the radioligand. An index of binding called the combined forward rate constant was decreased by 29% in dystonics, as compared with normals (p < 0.05). There were no significant differences between dystonics and normals in regional blood flow, blood volume, nonspecific binding, permeability-surface area product of [18F]spiperone or the dissociation rate constant. These findings are consistent with a decrease of dopamine D2-like binding in putamen and are the first demonstration of a receptor abnormality in idiopathic dystonia. These results have important implications for the pathophysiology of dystonia as well as for function of the basal ganglia.

Subdural hematoma as a cause of contralateral dystonia

A 72-year-old patient was operated on for a right-sided chronic subdural hematoma. After removal of the drain he became somnolent and developed dystonia of the left arm. Computerised tomography demonstrated a new right-sided subdural hematoma with compression of the right hemisphere and a midline shift to the contralateral side. Within hours after evacuation of the recurrent hematoma the dystonia disappeared. Rapid development and reversal is unusual in secondary dystonia. Mechanical compression, altered vascular supply, and metabolic changes may underlie the pathophysiology of this rare symptomatic movement disorder.

Basal ganglia and thalamo-cortical hypermetabolism in patients with spasmodic torticollis

The basal ganglia are thought to be involved in the primary dystonias, largely because of the repeated demonstration of neuropathological changes in these nuclei in the secondary dystonias. A hyperactivity of a network involving basal ganglia has been suggested in experimental animal dystonia. To test this hypothesis in humans, we studied the functional correlates of primary cervical dystonia using [18F]FDG and PET.

MATERIAL AND METHODS

Regional cerebral glucose metabolism (rCMRglc) was measured in 10 patients with idiopathic torticollis (6 drug-free and 4 drug-naive) and in 15 normal controls, using 2-[18F]-fluoro-2-deoxy-D-glucose ([18F]FDG) and positron emission tomography (PET).

RESULTS

A significant hypermetabolism in the basal ganglia, thalamus, premotor-motor cortex and cerebellum in the patients compared with normal controls was found. The patients were correctly assigned to their clinical category by a discriminant function analysis with a total accuracy of 96%.

CONCLUSION

The results support the hypothesis that a dysfunction of a subcortical-cortical motor network may play a role in the pathogenesis of focal dystonia, in agreement with the experimental dystonia models.

The syndrome of delayed posthemiplegic hemidystonia, hemiatrophy, and partial seizure: clinical, neuroimaging, and motor-evoked potential studies

Magnetic motor-evoked potential (MEP) study of patients with the syndrome of delayed posthemiplegic hemidystonia, hemiatrophy, and partial or hemi-seizures ('4-hemi' syndrome) has not been described. Among 35 patients investigated for posthemiplegic movement disorders from February 1988 to January 1995, seven showed '4-hemi' syndrome. Clinical work-up, magnetic resonance images (MRI) and/or computed tomography (CT) were performed in all. Transcranial MEP studies were done in five patients. The remote causes of '4-hemi' syndrome were neonatal stroke, trauma, and encephalitis in infancy. The dystonia may occur as long as a decade after the initial insult. MRI or CT showed destructive lesion in the contralateral putamen (five patients), caudate (four), thalamus (five), and atrophy of the contralateral hemisphere (five). Other associations were porencephalic cyst. Wallerian degeneration, and asymmetric compensatory ventriculomegaly. MEP showed abnormalities in the affected upper limbs in four of five patients. The abnormalities were reduced amplitude of the compound muscle action potential following cortical stimulations with or without temporal dispersion, and with or without prolongation of its latency. The peripheral motor conductions following cervical stimulations were normal. MEP abnormalities may not be related to the hemiatrophy and the size of brain lesion per se. The hemidystonia is static after the second decade of life, and it is often difficult to treat.

Symptomatic dystonias associated with structural brain lesions: report of 16 cases

BACKGROUND

Symptomatic (secondary) dystonias associated isolated lesions in the brain provide insight into etiopathogenesis of the idiopathic form of dystonia and are a basis for establishing the possible correlation between the anatomy of a lesion and the type of dystonia according to muscles affected.

METHODS

In 358 patients with differently distributed dystonias, a group of 16 patients (4.5%) was encountered in whom dystonia was associated with focal brain lesions.

RESULTS

Of the 16 patients, 3 patients had generalized, 3 segmental and 4 hemidystonia, while the remaining 6 patients had focal dystonia. The most frequent etiologies were infarction in 7, and tumor in 4 patients. These lesions were usually found in the lenticular and caudate nucleus, thalamus, and in the case of blepharospasm in the upper brainstem.

CONCLUSIONS

Our results support the suggestion that dystonia is caused by a dysfunction of the basal ganglia.

Paroxysmal dyskinesias: clinical features and classification

We studied 46 patients with paroxysmal dyskinesia and classified them according to phenomenology, duration of attacks, and etiology. There were 13 patients, 7 females, who had paroxysmal kinesigenic dyskinesia (PKD), 10 with attacks lasting 5 minutes or less (short lasting) and 3 with attacks lasting longer than 5 minutes (long lasting). Twenty-six patients, 18 females, had paroxysmal nonkinesigenic dyskinesia (PNKD), 9 with short-lasting and 17 with long-lasting PNKD. Five patients, 3 females, had paroxysmal exertion-induced dyskinesia (PED), 3 with short-lasting PED and the other 2 with long-lasting PED. In addition, there was 1 patient with paroxysmal hypnogenic dyskinesia (PHD) and 1 with paroxysmal superior oblique myokymia. Only 2 patients, 1 with PKD and 1 with PHD, had family history of paroxysmal dyskinesias. No specific cause could be identified in 21 patients; in the other 23 patients the etiologies included the following: psychogenic (9 patients), cerebrovascular diseases (4), multiple sclerosis (2), encephalitis (2), cerebral trauma (2), peripheral trauma (2), migraine (1), and kernicterus (1). Nine of 10 (90%) patients with PKD improved with medications, mostly anticonvulsants, compared with only 7 of 19 (37%) with PNKD. This new classification, based chiefly on precipitating events, allowed appropriate categorization of the attacks in all our patients with paroxysmal dyskinesias.

[Kinesigenic paroxysmal choreoathetosis. Report of a case treated with carbamazepine]

Paroxysmal choreoathetosis (PC) is a rare entity, and professionals who study movement disorders do not find it easily. Paroxysmal occurrence of dystonic, choreic, athetosic movements is the typical feature of this syndrome. The onset is always subtle and the attacks can last from few seconds to hours. Sporadic cases and more common familial cases have been reported. The therapeutic approach with anticonvulsant drugs like carbamazepine is not always successful. However, there is a good response to this drug in the kinesigenic form of PC. The case of a 21 years old male patient is reported here. The onset occurred during puberty, at 14 years old. Neurologic examination was normal between attacks. Subtle and brief choreic, athetosic and dystonic limb and legs movements precipitated by sudden quick and unexpected passive movements, as by startle, were observed during the attacks. There was no familial history. Routine laboratorial investigation, EEG, CT scan and MRI did not show significant changes. Carbamazepine in low dosages (100 mg/day) brought a complete control of the attacks.

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.

Corticobasal degeneration: decreased and asymmetrical glucose consumption as studied with PET

Cerebral energy metabolism was studied by positron emission tomography and [18F]fluorodeoxyglucose in five patients with clinical diagnoses of probable corticobasal degeneration. A reduction in glucose consumption was observed in most cortical and subcortical structures compared to age-matched controls. The reduction was greatest on the side of the brain contralateral to the most affected limbs, as shown by the significantly lower ratios of contralateral to homolateral metabolic rates, in the temporal and sensorimotor cortex of patients compared to controls. A distinct asymmetry between the two hemispheres could be observed in a patient who was examined twice in the course of his illness. Detection of this asymmetrical decrease in brain cortical and subcortical glucose metabolism may prove useful as additional evidence supporting clinical diagnoses of the disease.

Posttraumatic segmental axial dystonia

Isolated dystonia of trunk and neck muscles without involvement elsewhere has been termed segmental axial dystonia--a rare disorder. We report a 31-year-old man who developed marked dystonia of paraspinal muscles and progressive scoliosis 6 months after a closed head injury. Computed tomography (CT) disclosed three small areas of encephalomalacia, one involving the head of the caudate nucleus. Treatment with trihexyphenidyl resulted in significant improvement of the dystonia and scoliosis.

Dystonia following head trauma: a report of nine patients and review of the literature

We report nine patients who developed dystonia following head trauma. The most frequent form was hemidystonia only (six patients). One patient presented with hemidystonia plus torticollis, one with bilateral hemidystonia and one with torticollis only. Seven patients sustained a severe head injury, and two had a mild head injury. At the time of injury, six were younger than 10 years, two were adolescents, and the patient with torticollis only was an adult. Except in the patient with torticollis only, the onset of dystonia varied considerably from months to years. All patients with hemidystonia had posthemiplegic dystonia of delayed onset. Seven out of 8 patients with hemidystonia had lesions involving the contralateral caudate or putamen, as demonstrated by CT and MR. The patient with hemidystonia plus torticollis had no lesion to the basal ganglia, but a contralateral pontomesencephalic lesion. Response to medical treatment was generally poor. Functional stereotactic operations were performed in seven patients. A variety of factors may be responsible for the vascular or nonvascular posttraumatic basal ganglia lesions, which may lead to dystonia. The pathophysiology seems to be more complex than thought previously. We believe that dystonia following head injury is not as rare as is assumed. Awareness of its characteristics and optimized diagnostic procedures will lead to wider recognition of this entity.

New approaches in the treatment of the dystonias

At this point the treatment of dystonias remains highly empirical. Secondary dystonias, especially those related to specific drug treatment, have to be ruled out carefully. A few dystonic subgroups respond well to levodopa medication. In the other syndromes, anticholinergics are the usual first choice. In focal conditions botulinum toxin injections seem to be the most effective regimen, although there are only a few long-term studies. Surgical procedures are an ultimate option.

PET and movement disorders

In this paper the use of PET for determining the patterns of disruption of both regional cerebral metabolism, and the pre- and post-synaptic dopaminergic systems, associated with movement disorders is reviewed. That the various akinetic-rigid syndromes result in distinctive PET findings is shown, making functional imaging valuable in their differential diagnosis. PET may also be useful for detecting the presence of sub-clinical disease in Huntington's disease and other inherited movement disorders.

Acquired focal dystonia following recovery from central pontine myelinolysis

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Neurochemical findings in neuroacanthocytosis

We performed a neurochemical study of the brain of two unrelated patients, living in different continents, with neuroacanthocytosis. The levels of monoamines and their metabolites, gamma-aminobutyric acid and substance P, were measured in several brain areas and the monoamine metabolites in cerebrospinal fluid. The binding of 3H-spiperone to striatal membranes and to lymphocytes was also measured. Both patients had a progressive neurological disorder with onset in the third decade of life and characterized by a complex movement disorder, epilepsy, muscular wasting, and changes in behavior. The movement disorder initially manifested with oromandibular dystonia and limb chorea, but at the time of death was characterized by a severe dystonic syndrome. The chemical changes were similar in the two patients. The most important neurochemical findings were a depletion of dopamine and its metabolites in most brain areas, most notably in the striatum, and elevation of norepinephrine levels in the putamen and globus pallidus. Substance P was markedly reduced in the striatum and substantia nigra. Our findings may provide clues to the neurochemical mechanisms underlying dystonia.

Pathological report of four patients presenting with cranial dystonias

Secondary dystonias and experimental models of dystonia suggest that mechanisms responsible for primary dystonias may lie in the basal ganglia or brainstem. A histological study has been done in three patients with cranial dystonia (blepharospasm with oromandibular dystonia in two, blepharospasm alone in one), and one patient with craniocervical dystonia (oromandibular dystonia with retrocollis). In the patient with blepharospasm alone, an angioma, 0.5 mm in diameter, was found in the dorsal pons at the site of the central tegmental tract, confirming that some patients presenting with primary dystonias may have longstanding lesions in the brainstem. In the three other cases, the striatum, pallidum, thalamus, and brainstem were examined and cell populations in the putamen, substantia nigra, and inferior olives were compared with age-matched controls, but no significant abnormality was found.

Standardized mean regional method for calculating global positron emission tomographic measurements

A new "mean regional" method for calculating global hemispheric values of blood flow, blood volume, and metabolism with positron emission tomography is presented. It is based on a standardized set of regions defined according to coordinates in a stereotactic atlas of the brain. Region locations in each individual scan were determined by a localization technique that is independent of the appearance of the physiological images. Measurements obtained with this mean regional method minimize contributions from nonbrain structures such as ventricles or venous sinuses and provide the necessary basis for comparisons among different subjects and laboratories.

Hemidystonia: a report of 22 patients and a review of the literature

Hemidystonia defined as involuntary, sustained posturing of the unilateral arm, leg, and face was studied in 12 male and 10 female patients. Hemidystonia was caused by cerebrovascular disease in eight patients, perinatal trauma or childhood injury in four, head trauma and its sequelae in three, neuronal storage disorders in two, neurodegenerative disease in two, lesions after thalamotomy in two, and presumed encephalitis in one. Sixteen patients (73%) had CT evidence of contralateral basal ganglia damage, history of hemiparesis, or both. Brain damage before 7 years of age produced contralateral hemidystonia with a mean delay of 9-7 years. In older patients hemidystonia appeared within 6 months after injury. Hemidystonia may result from a disconnection between the striatum and the thalamus with relative preservation of the corticospinal pathways.

Positron emission tomography in movement disorders

Positron emission tomography provides a method for the quantitation of regional function within the living human brain. Studies of cerebral metabolism and blood flow in patients with Huntington's disease, Parkinson's disease and focal dystonia have revealed functional abnormalities within substructures of the basal ganglia. Recent developments permit assessment of both pre-synaptic and post-synaptic function in dopaminergic pathways. These techniques are now being applied to studies of movement disorders in human subjects.