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At least 19 recordsLinked to original sources
PubMed1999

Thalamic single neuron activity in patients with dystonia: dystonia-related activity and somatic sensory reorganization.

Indirect evidence suggests that the thalamus contributes to abnormal movements occurring in patients with dystonia (dystonia patients). The present study tested the hypothesis that thalamic activity contributes to the dystonic movements that occur in such patients. During these movements, spectral analysis of electromyographic (EMG) signals in flexor and extensor muscles of the wrist and elbow exhibited peak EMG power in the lowest frequency band [0-0.78 Hz (mean: 0.39 Hz) dystonia frequency] for 60-85% of epochs studied during a pointing task. Normal controls showed low-frequency peaks for <16% of epochs during pointing. Among dystonia patients, simultaneous contraction of antagonistic muscles (cocontraction) at dystonia frequency during pointing was observed for muscles acting about the wrist (63% of epochs) and elbow (39%), but cocontraction was not observed among normal controls during pointing. Thalamic neuronal signals were recorded during thalamotomy for treatment of dystonia and were compared with those of control patients without motor abnormality who were undergoing thalamic procedures for treatment of chronic pain. Presumed nuclear boundaries of a human thalamic cerebellar relay nucleus (ventral intermediate, Vim) and a pallidal relay nucleus (ventral oral posterior, Vop) were estimated by aligning the anterior border of the principal sensory nucleus (ventral caudal, Vc) with the region where the majority of cells have cutaneous receptive fields (RFs). The ratio of power at dystonia frequency to average spectral power was >2 (P < 0.001) for cells in presumed Vop often for dystonia patients (81%) but never for control patients. The percentage of such cells in presumed Vim of dystonia patients (32%) was not significantly different from that of controls (31%). Many cells in presumed Vop exhibited dystonia frequency activity that was correlated with and phase-advanced on EMG activity during dystonia, suggesting that this activity was related to dystonia. Thalamic somatic sensory activity also differed between dystonia patients and controls. The percentage of cells responding to passive joint movement or to manipulation of subcutaneous structures (deep sensory cells) in presumed Vim was significantly greater in patients with dystonia than in control patients undergoing surgery for treatment of pain or tremor. Dystonia patients had a significantly higher proportion of deep sensory cells responding to movement of more than one joint (26%, 13/52) than did "control" patients (8%, 4/49). Deep sensory cells in patients with dystonia were located in thalamic maps that demonstrated increased representations of parts of the body affected by dystonia. Thus dystonia patients showed increased receptive fields and an increased thalamic representation of dystonic body parts. The motor activity of an individual sensory cell was related to the sensory activity of that cell by identification of the muscle apparently involved in the cell's receptive field. Specifically, we defined the effector muscle as the muscle that, by contraction, produced the joint movement associated with a thalamic neuronal sensory discharge, when the examiner passively moved the joint. Spike X EMG correlation functions during dystonia indicated that thalamic cellular activity less often was related to EMG in effector muscles (52%) than in other muscles (86%). Thus there is a mismatch between the effector muscle for a thalamic cell and the muscles with EMG correlated with activity of that cell during dystonia. This mismatch may result from the reorganization of sensory maps and may contribute to the simultaneous activation of multiple muscles observed in dystonia. Microstimulation in presumed Vim in dystonia patients produced simultaneous contraction of multiple forearm muscles, similar to the simultaneous muscle contractions observed in dystonia. (ABSTRACT TRUNCATED)

Brain Mapping↗
PubMed2004

Off-period dystonia in Parkinson's disease but not generalized dystonia is improved by high-frequency stimulation of the subthalamic nucleus.

STN-HFS is well known to improve patients with IPD. Because off-period dystonia mimics focal or generalized dystonia of other causes, we proposed bilateral STN-HFS to some patients with generalized dystonia. The aim of this study was to compare the efficacy of STN stimulation on off-period dystonia and generalized dystonia. From a larger series of patients with IPD, we selected 22 patients based on the presence of severe preoperative off-period dystonia rated > or = 3 in least one limb on a severity score ranging from 0 to 4. Four patients with generalized dystonia (Hallervorden-Spatz disease, n = 3; primary, n = 1) underwent bilateral STN-HFS. Dystonia of the four limbs was rated on video recordings in all patients before surgery and 3 months after surgery. In IPD, bilateral STN stimulation reduced the severity of off-period dystonia by 70% on the four limbs (preoperative mean severity score = 2.03 +/- 1.49; postoperative mean severity score = 0.60 +/- 0.78). In contrast, bilateral STN-HFS had no effect on generalized dystonia (preoperative mean severity score = 3.25 +/- 0.77; postoperative mean severity score = 3.12 +/- 0.62). Despite clinical similarities between off-period dystonia in Parkinson's disease and generalized dystonia in certain cases, the effect of chronic bilateral STN-HFS differs. STN stimulation is highly effective in off-period dystonia of IPD, whereas it does not improve generalized dystonia. The pathophysiologic mechanisms underlying dystonia in these two disorders are still unknown. Assuming that the mechanism of action of STN-HFS is similar regardless of the cause of dystonia, our findings suggest that the STN is not similarly involved in off-period dystonia of IPD and others dystonias.

Adult↗
PubMed2004

Primary dystonia is more responsive than secondary dystonia to pallidal interventions: outcome after pallidotomy or pallidal deep brain stimulation.

OBJECTIVE: The response of patients with dystonia to pallidal procedures is not well understood. In this study, we assessed the postoperative outcome of patients with primary and secondary dystonia undergoing pallidotomy or pallidal deep brain stimulation. METHODS: Fifteen patients with dystonia had pallidal surgery (lesions or deep brain stimulation). These included nine patients with primary dystonia (generalized and cervical dystonias) and six with secondary dystonia (generalized, segmental, and hemidystonias). There were nine male patients and six female patients. The mean age at onset was 21 years for primary dystonia and 18 years for secondary dystonia. The primary outcome measure was a Global Outcome Scale score for dystonia at 6 months after surgery. Other outcome measures were the Burke-Fahn-Marsden Dystonia Rating Scale and Toronto Western Spasmodic Torticollis Rating Scale scores. RESULTS: The mean Global Outcome Scale score at 6 months for patients with primary dystonia was 3 (improvement in both movement disorder and function). In contrast, patients with secondary dystonia had a mean score of 0.83 (mild or no improvement in movement disorder with no functional improvement). All patients with primary dystonia had normal brains by magnetic resonance imaging, whereas five of six patients with secondary dystonia had basal ganglia abnormalities on their magnetic resonance imaging scans. CONCLUSION: This study indicates that primary dystonia responds much better than secondary dystonia to pallidal procedures. We could not distinguish a difference in efficacy between pallidotomy and pallidal deep brain stimulation. The presence of basal ganglia abnormalities on the preoperative magnetic resonance imaging scan is an indicator of a lesser response to pallidal interventions for dystonia.

Adolescent↗
PubMed2006

A systematic review on the diagnosis and treatment of primary (idiopathic) dystonia and dystonia plus syndromes: report of an EFNS/MDS-ES Task Force.

To review the literature on primary dystonia and dystonia plus and to provide evidence-based recommendations. Primary dystonia and dystonia plus are chronic and often disabling conditions with a widespread spectrum mainly in young people. Computerized MEDLINE and EMBASE literature reviews (1966-1967 February 2005) were conducted. The Cochrane Library was searched for relevant citations. Diagnosis and classification of dystonia are highly relevant for providing appropriate management and prognostic information, and genetic counselling. Expert observation is suggested. DYT-1 gene testing in conjunction with genetic counselling is recommended for patients with primary dystonia with onset before age 30 years and in those with an affected relative with early onset. Positive genetic testing for dystonia (e.g. DYT-1) is not sufficient to make diagnosis of dystonia. Individuals with myoclonus should be tested for the epsilon-sarcoglycan gene (DYT-11). A levodopa trial is warranted in every patient with early onset dystonia without an alternative diagnosis. Brain imaging is not routinely required when there is a confident diagnosis of primary dystonia in adult patients, whereas it is necessary in the paediatric population. Botulinum toxin (BoNT) type A (or type B if there is resistance to type A) can be regarded as first line treatment for primary cranial (excluding oromandibular) or cervical dystonia and can be effective in writing dystonia. Actual evidence is lacking on direct comparison of the clinical efficacy and safety of BoNT-A vs. BoNT-B. Pallidal deep brain stimulation (DBS) is considered a good option, particularly for generalized or cervical dystonia, after medication or BoNT have failed to provide adequate improvement. Selective peripheral denervation is a safe procedure that is indicated exclusively in cervical dystonia. Intrathecal baclofen can be indicated in patients where secondary dystonia is combined with spasticity. The absolute and comparative efficacy and tolerability of drugs in dystonia, including anticholinergic and antidopaminergic drugs, is poorly documented and no evidence-based recommendations can be made to guide prescribing.

Botulinum Toxins↗
PubMed2006

Predominant dystonia with marked cerebellar atrophy: a rare phenotype in familial dystonia.

BACKGROUND: Dystonia syndromes constitute a heterogeneous group of phenotypes that may be caused by different heredodegenerative, metabolic, or genetic diseases. OBJECTIVE: To describe the characteristics of an unusual dystonia-plus phenotype associated with cerebellar atrophy. METHODS: We selected patients with predominant dystonia and cerebellar atrophy among the 861 families referred to us for genetic testing from 1992 to 2003. The main secondary heredodegenerative causes and the major genes responsible for hereditary dystonias and autosomal dominant or recessive ataxias were excluded. RESULTS: We identified 12 patients in 8 families with an unusual dystonia-plus phenotype characterized by dystonia and cerebellar atrophy on brain MRI. The mean age at onset was 27.3 +/- 11.5 years (range: 9 to 42 years) and the mean disease duration 14.7 +/- 7.7 years (range: 4 to 30). At onset, dystonia was focal or multifocal, mainly affecting vocal cords (n = 8) and upper limbs (n = 2). During the disease course spasmodic dysphonia became severe in five patients, leading to complete aphonia in two. Dystonia became generalized in five. Cerebellar ataxia was limited to unsteadiness in most patients and progressed very slowly. The paucity of clinical cerebellar signs contrasted with the marked cerebellar atrophy on brain MRI in most patients. Four families with two affected sibs support the hypothesis of an autosomal recessive disorder. However, X-linked inheritance is possible since only men were affected. CONCLUSION: We have characterized an unusual familial phenotype associating dystonia and cerebellar atrophy in 12 male patients.

Adult↗
PubMed2002

Chronic high-frequency globus pallidus internus stimulation in different types of dystonia: a clinical, video, and MRI report of six patients presenting with segmental, cervical, and generalized dystonia.

The results of deep brain stimulation (DBS) of the globus pallidus internus (Gpi) in six patients with generalized, focal, and segmental dystonia are presented. Pre- and postoperative assessments are given for one patient with generalized inherited dystonia and for five patients with idiopathic segmental or cervical dystonia. Clinical symptoms were evaluated before and 3-12 months after surgery using the Burke-Fahn-Marsden (BFM) dystonia rating scale for primary torsion dystonia and the Tsui scale for cervical dystonia. The Short-Form Health Survey (SF-36) was completed by each patient to document preoperative and postoperative health status. Also, neurological status was documented by video before and during chronic stimulation. Magnetic resonance imaging studies were performed to show the anatomical localization of the electrode leads. Five patients showed a progressive improvement within 7 days. One patient with cervical dystonia and Meige's syndrome showed no improvement for 3 months, but beneficial effects were observed after 12 months. On average, the BFM movement scale scores decreased by 72.5% and Tsui scale scores by 63%. SF-36 showed an improvement in health status by an average of 36% according to eight different health categories. We conclude that chronic high-frequency Gpi stimulation in different types of dystonia is a very effective and safe treatment.

Adult↗
PubMed2000

Neuronal activity in the globus pallidus in primary dystonia and off-period dystonia.

Decreased neuronal activity and altered firing patterns in the globus pallidus have been commonly observed in primary dystonia. Intraoperative neuronal recording in a patient with off-period dystonia revealed that the mean firing rates were considerably low in both the internal and external segments of the globus pallidus and that firing was irregular in the internal segment of the globus pallidus when dystonia developed, as compared with firing patterns in off-state parkinsonian patients without dystonia. These altered firing patterns were immediately reversed to those of off-state parkinsonism after relief of dystonia. These results suggest that primary dystonia and off-period dystonia result from the same physiological change in the basal ganglia. Ablation and stimulation of the internal segment of the globus pallidus can abolish both types of dystonia by blocking the abnormal activity of pallidal neurons.

Dystonia↗
PubMed2007

Does dystonia always include co-contraction? A study of unconstrained reaching in children with primary and secondary dystonia.

Dystonia is a movement disorder in which involuntary or intermittent muscle contractions cause twisting and repetitive movements, abnormal postures, or both. Excessive co-contraction and abnormalities in the time course of reciprocal inhibition between antagonist groups of muscles are considered to be cardinal features of some types of dystonia and reduced speed of movement is often attributed to involuntary activation of antagonist muscles about a joint. In the present study we describe muscle activity during unconstrained multi-joint reaching movements. Children diagnosed with arm dystonia due to cerebral palsy (CP) or primary dystonia (n=7, 4-16 years, 4 with CP, 3 primary) and similar age healthy subjects pointed alternately to two targets as fast as possible. The children with dystonia showed decreased speed, greater variability, and pauses at targets compared with controls. Decreased speed was mostly due to difficulty in reversing reaching direction, and increased variability was associated with large fluctuations in the duration of the pauses at targets, rather than with variations in the flexion/extension velocity profiles. Surface electromyographic (EMG) activities were examined to assess if the abnormalities observed in the children with dystonia could be explained in terms of increased levels of co-contraction. Unexpectedly, we found that the children with dystonia showed lower levels of co-contraction than the controls during movement, and the pauses at tar-gets were associated with reduced levels of activation rather than with excessive activity in antagonist groups of muscles. Therefore reduced speed of movement during unconstrained reaching may not be due to involuntary activation of the antagonist muscle, and co-contraction of opposing muscles about a joint is not an obligatory feature of multi-joint movement in children with dystonia.

Adolescent↗
PubMed1991

Identification of a highly polymorphic microsatellite VNTR within the argininosuccinate synthetase locus: exclusion of the dystonia gene on 9q32-34 as the cause of dopa-responsive dystonia in a large kindred.

Dopa-responsive dystonia is a clinical variant of idiopathic torsion dystonia that is distinguished from other forms of dystonia by the frequent occurrence of parkinsonism, diurnal fluctuation of symptoms, and its dramatic therapeutic response to L-dopa. Linkage of a gene causing classic dystonia in a large non-Jewish kindred (DYT1) and in a group of Ashkenazi Jewish families, to the gelsolin (GSN) and arginino-succinate synthetase (ASS) loci on chromosome 9q32-34, respectively, was recently determined. Here we report the discovery of a highly informative (GT)n repeat VNTR polymorphism within the ASS locus. Analysis of a large kindred with dopa-responsive dystonia, using this new polymorphism and conventional RFLPs for the 9q32-34 region, excludes loci in this region as a cause of this form of dystonia. This provides proof of genetic heterogeneity between classic idiopathic torsion dystonia and dopa-responsive dystonia.

Argininosuccinate Synthase↗
PubMed1988

Blink reflex studies in focal dystonias: enhanced excitability of brainstem interneurons in cranial dystonia and spasmodic torticollis.

We have studied the orbicularis oculi reflex to paired stimuli in patients with various forms of focal dystonia and in normal controls. In normals, the conditioning stimulus (CS) facilitated the test stimulus (TS) early response (R1), but markedly inhibited the TS polysynaptic late response (R2). In all types of dystonias studied the CS facilitated the TSR1 as in normals. However, in patients with blepharospasm (alone or associated with oromandibular dystonia), spasmodic torticollis, or spasmodic dysphonia, it inhibited the TSR2 significantly less than that of the controls, with marked enhancement of the recovery curve of the late response. The TSR2 recovery curve of patients with focal arm dystonia was normal. These results are indicative of increased brainstem interneuron excitability in the various dystonias mediated by the cranial nerves, but not in focal arm dystonias such as dystonic writer's cramp. This abnormality might be caused by an abnormal input possibly from the basal ganglia upon these brainstem cells. Our results also suggest that a similar pathophysiology underlies the various focal dystonias of the head and neck.

Blepharospasm↗
PubMed1990

Botulinum toxin treatment of cranial-cervical dystonia, spasmodic dysphonia, other focal dystonias and hemifacial spasm.

In the past five years, 477 patients with various focal dystonias and hemifacial spasm received 3,806 injections of botulinum A toxin for relief of involuntary spasms. A definite improvement with a global rating greater than or equal to 2 on a 0-4 scale, was obtained in all 13 patients with spasmodic dysphonia, 94% of 70 patients with blepharospasm, 92% of 13 patients with hemifacial spasm, 90% of 195 patients with cervical dystonia, 77% of 22 patients with hand dystonia, 73% of 45 patients with oromandibular dystonia, and in 90% of 21 patients with other focal dystonia who had adequate follow up. While the average duration of maximum improvement lasted about 11 weeks after an injection (range seven weeks in patients with hand dystonia to 15 weeks in patients with hemifacial spasm), some patients benefited for over a year. Only 16% of the 941 treatment visits with follow up were not successful. Except for transient focal weakness, there were very few complications or systemic effects attributed to the injections. This study supports the conclusion that botulinum toxin injections are a safe and effective therapy for patients with focal dystonia and hemifacial spasm.

Adolescent↗
PubMed1982

Tardive dystonia: late-onset and persistent dystonia caused by antipsychotic drugs.

It is not widely recognized that antipsychotic drugs can cause late-onset and persistent dystonia. This dystonia, which we call tardive dystonia, is to be distinguished from acute dystonic reactions, which are transient, and from classic tardive dyskinesia, which is a choreic disorder that predominantly affects the oral region. We present 42 patients with tardive dystonia. The age of onset of dystonia was 13 to 60 years. Symptoms began after 3 days to 11 years of antipsychotic therapy. Younger patients tended to have more generalized dystonia. In a few patients, spontaneous remission occurred, but dystonia persisted for years in most. Therapy was rarely a complete success. The most frequently helpful medications were tetrabenazine (68% of patients improved) and anticholinergics (39% improved).

Adolescent↗
PubMed1997

MPTP induces dystonia and parkinsonism. Clues to the pathophysiology of dystonia.

The pathophysiology of dystonia is unclear, but several clues implicate striatal dopamine dysfunction. In contrast, the causal relationship between striatal dopamine deficiency and parkinsonism is well defined. We now suggest that parkinsonism or dystonia may occur following striatal dopamine deficiency. Baboons treated with intracarotid 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) developed transient hemidystonia prior to hemiparkinsonism. The day after MPTP treatment, most animals had spontaneous ipsilateral turning. Within a few days, all developed contralateral hemidystonia, with the arm and leg extended and externally rotated. This transient dystonia preceded hemiparkinsonism with flexed posture, bradykinesia, and postural tremor that persisted for up to 1.5 years. Dystonia corresponded temporally with a decreased striatal dopamine content and a transient decrease in D2-like receptor number. The time course of dystonia and parkinsonism is analogous to lower limb dystonia as the first, frequently transient, symptom of Parkinson's disease in humans. The association of striatal dopamine deficiency with dystonia and parkinsonism implies that other factors influence clinical manifestations.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1999

Sex-related influences on the frequency and age of onset of primary dystonia. Epidemiologic Study of Dystonia in Europe (ESDE) Collaborative Group.

We studied 957 cases of primary (idiopathic) dystonia and found a significant excess of female patients for segmental and focal dystonia. A novel observation was a significantly earlier age at onset in males as opposed to females for primary segmental (mean age, 44.6 versus 53.3) and focal dystonia (43.8 versus 47.8). This trend was also apparent in cervical dystonia, blepharospasm, and laryngeal dystonia. For writer's cramp and focal limb dystonia, this trend was reversed with an earlier age at onset in females. These results suggest that focal dystonia should not be treated as an homogenous group, and sex-linked factors may play a role.

Adult↗
PubMed1992

Treatment of cervical dystonia hand spasms and laryngeal dystonia with botulinum toxin.

One hundred and twenty-six patients with different forms of focal dystonia (89 with cervical dystonia, 12 with hand cramps and 25 with laryngeal dystonia) were treated with localised injections of botulinum toxin. Mean doses per muscle were 200 mouse units (m.u.) for treating cervical dystonia, 40-120 m.u. for forearm muscles in writers' cramp and 3.7 m.u. for the thyroarytenoid muscle in laryngeal dystonia. Responder rates have been above 80% in all patient groups and beneficial effects could be reproduced over follow-up periods of up to 4 years. The commonest side-effects were dysphagia after treatment of spasmodic torticollis, weakness of neighbouring muscles after injections for hand cramps and breathiness and hypophonia following laryngeal injections. All these were transient and generally well tolerated. It is concluded that botulinum toxin injections are a safe and effective treatment in all three types of focal dystonia.

Botulinum Toxins↗
PubMed1996

Refractory dystonia during propofol anaesthesia in a patient with torticollis-dystonia disorder.

PURPOSE: To report a case of refractory dystonia under propofol anaesthesia in a patient with Torticollis-Dystonia disorder. CLINICAL FEATURES: A 38-yr-old man presented for an MRI scan for investigation of a Torticollis-Dystonia disorder. There was a biphasic response to propofol with complete amelioration of the torticollis and limb dystonia initially with subsequent recurrence under deep propofol anaesthesia. Coadministration of midazolam, diazepam, and thiopentone were not successful in abolishing the recurrent dystonia. CONCLUSIONS: Propofol should preferably be avoided in patients with torticollis and dystonias. Where complete control of movements is required, it may be necessary to consider general endotracheal anaesthesia with muscle relaxants.

Adult↗