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Query: UMLS:C0027066 (myoclonus)
 4,275 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hereditary autosomal dominant myoclonus dystonia (MD) is a movement disorder characterized by involuntary lightning jerks and dystonic movements and postures alleviated by alcohol. Although various large families with MD have been described, no positive linkage has been found to a chromosomal location. We report a family with eight members with MD. Linkage analysis identified a 23-centimorgan region on chromosome 11q23 that cosegregates with the disease state (maximum multipoint logarithm of odds score = 2.96 at D11S897). This region contains an excellent candidate gene for involvement in the etiology of MD, the D2 dopamine receptor (DRD2) gene. Neurotransmission mediated by DRD2 is known to have a key role in the control of movement and also has been implicated in reward and reinforcement mechanisms and psychiatric disorders. Sequencing of the coding region of DRD2 indicated that all affected and obligate carriers were heterozygous for a Val154Ile change in exon 3 of the protein, which is highly conserved across species. This change was found neither in other unaffected members of the pedigree nor in 250 control chromosomes. Our finding provides evidence for the involvement of DRD2 in a disorder of the central nervous system and should lead to further insight into the function of the dopaminergic system in dystonia and other movement and mood disorders.
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PMID:Association of a missense change in the D2 dopamine receptor with myoclonus dystonia. 1022 Apr 38

Movement disorders in children encompass disorders of motor control--both hyperkinetic (excessive movement) and hypokinetic (decreased movement). This article focuses on the hyperkinetic movement disorders, particularly tremor, Wilson's disease, dystonia, tics and Tourette syndrome, chorea, myoclonus, neuroleptic-induced movement disorders, and psychogenic movement disorders. Phenomenology of the disorders as well as clinical presentation, basic pathophysiology, genetics, and treatment are discussed.
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PMID:Pediatric movement disorders. 1055 1

Recently it has been discovered that defects in neuronal ion channels can result in seizure disorders. The tottering mouse is a genetic animal model carrying a mutation in the alpha1A calcium channel subunit that causes these mice to exhibit generalized petit mal-like epilepsy, cerebellar ataxia, and an intermittent movement disorder that has some characteristics similar to myoclonus or myoclonic epilepsy. We postulate that abnormal cerebellar Purkinje cell output to the deep cerebellar nuclei results in the intermittent movement disorder observed in these mice. The frequency and duration of seizure activity were measured in tottering mice before and 2 weeks after surgical or chemical lesioning of the cerebellum. Surgical lesions in the anterior cerebellar vermis of tottering mice produced significant reductions in seizure duration and frequency. Surgical lesioning of the posterior cerebellar vermis had no significant effect. Chemical lesions of the same cerebellar regions, using a locally applied neurotoxin, NMD-L-A, appear to produce effects similar to the surgical lesions. These data indicate that anterior vermal cerebellar output is important for production of the seizures associated with the intermittent movement disorder observed in tottering mice.
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PMID:Investigation of the role of the cerebellum in the myoclonic-like movement disorder exhibited by tottering mice. 1075 73

Tremor is the most common involuntary movement disorder. It is differentiated from other involuntary movement disorders, such as chorea, athetosis, ballismus, tics, and myoclonus, by its repetitive, stereotyped, movements of a regular amplitude and frequency. Tremor can be defined as an involuntary, rhythmic, periodic, mechanical oscillation of a body part. Since small-amplitude tremors may not be visible to the naked eye and may only be detectable by sensitive recording devices, amplitude of the tremor is therefore not critical to the definition. Accurate diagnosis of tremor is important because appropriate treatment depends on the accuracy of the clinical diagnosis. This article reviews the classification and management of tremor.
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PMID:Diagnosis and management of tremor. 1097 54

High-frequency thalamic stimulation alleviates tremor in Parkinson's disease (PD) and essential tremor (ET). The origin of thalamic myoclonus is unexplained and the effects of low-frequency thalamic stimulation on movement control are still unknown. We studied the effects of stimulation at a low frequency of 15 Hz in five drug-free patients (3 PD, 2 ET) 6 months after thalamic implantation of quadripolar electrodes (unilateral in four patients, bilateral in one patient). Clinical, electrophysiological, and videotaped assessment, using a monopolar 15 Hz frequency (3 V, 90 micros) stimulation current applied simultaneously through two adjacent contacts of the electrode, was performed. We observed myoclonus and irregular jerky tremor in the upper limb contralateral to the site of stimulation. The jerks lasted less than 200 ms, were irregular and not synchronous with stimulation, were superimposed on rest or postural tremor, and increased in response to tactile, proprioceptive, or vibratory stimuli. The fact that this complex movement disorder can be induced by low-frequency stimulation in the ventral intermediate nucleus (Vim) of the thalamus suggests that it results, at least partly, from dysfunction of the Vim and possibly adjacent nuclei of the thalamus.
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PMID:Irregular jerky tremor, myoclonus, and thalamus: a study using low-frequency stimulation. 1100

We report a case of autosomal dominantly inherited dystonia and panic attacks to discuss successful treatment of a common serotonergic pathology with medication. The objective analysis of the movement disorder was done by Optotrak. First we demonstrate a reduction of the myoclonus by L-5-hydroxytryptophan, which inhibits after 11 months. After changing the medication to Nefadozone, the myoclonus and the frequency of panic attacks were reduced.
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PMID:[Familial myoclonus-dystonia syndrome associated with panic attacks]. 1108 16

Involuntary movements or hyperkinesias are classified into syndromes of chorea, ballism, tremor, dystonia, myoclonus and tics. The hyperkinesias are caused by disturbances in the circuitry connecting the cerebral cortex, thalamus, basal ganglia and cerebellum. Drugs are a common cause of movement disorders. The aim of management is to characterise the movement disorder, identify and treat the cause or institute symptomatic treatment. The genetic basis of many movement disorders is increasingly recognised. Where there are potential implications for family members, accurate diagnosis and counselling are particularly important.
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PMID:6: Movement disorders II: the hyperkinetic disorders. 1134 89

A 15-year-old female adolescent with depression developed myoclonus after uninterrupted treatment with sertraline over 6 years. She was also receiving methylphenidate. Withdrawal of sertraline and continuation of methylphenidate did not result in any improvement. Treatment with valproic acid resulted in improvement of the movement disorder. This report suggests that myoclonus may be a side effect of sertraline in some adolescents. Further, we hypothesized that extended treatment over several years, young age, and a compromised central nervous system due to underlying disorders may be risk factors for the development of this side effect.
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PMID:Myoclonus during prolonged treatment with sertraline in an adolescent patient. 1143 61

Involuntary movements may be a symptom in most infants who present with neurologic syndrome of infantile cobalamin (vitamin B12) deficiency. In this report, two infants with cobalamin deficiency are presented. These patients also developed a striking movement disorder that appeared a few days after treatment with intramuscular cobalamin. The movement disorder was characterized by severe involuntary movements, which were a combination of tremor and myoclonus particularly involving tongue, face, pharynx, and legs. The neurologic symptoms improved within a few days after the administration of clonazepam. In each patient the mother was also cobalamin deficient and the infant was solely breast-fed. The cause of involuntary movements that can appear rarely after treatment in infantile cobalamin deficiency is not known. Besides initial neurologic presenting symptoms of cobalamin deficiency, the occurrence of involuntary movements after treatment should also receive attention. This movement disorder may disappear spontaneously, or an additional treatment may be an alternative approach if the symptoms are severe.
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PMID:Involuntary movements in infantile cobalamin deficiency appearing after treatment. 1207 71

This article defines myoclonus, describes the numerous causes of myoclonus, and summarizes various classification schemes. The electrodiagnostic characteristics and pathophysiology of this movement disorder are described. Treatment of the various forms of myoclonus is also discussed.
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PMID:Myoclonus and its disorders. 1153 51


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