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

The authors report the clinical criteria for the diagnosis of progressive myoclonus epilepsies on the basis of their experience following 34 cases (2 with sialidosis, 2 with MERRF, 4 with Lafora disease, 24 with Unverricht-Lundborg type, 4 with ataxic myoclonus). 3 rare forms of PME are also reported: a case of lipoma and PME, a family with dentato-rubro-pallido-luysian atrophy and a family of myoclonus epilepsy, Hartung type. The autonomy of Ramsay Hunt syndrome is discussed on the light of recent molecular genetic data.
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PMID:Progressive myoclonus epilepsies. Criteria for diagnosis on the basis of the follow-up of 37 cases. 129 89

It has been found that PME without Lafora bodies is more common in Finland than elsewhere. The incidence is 1:20,000. The mode of inheritance is autosomal recessive. At first the children are healthy. Stimulus-sensitive myoclonic jerks and grand mal seizures appear at the age of 6 to 15 years. The EEG shows a generalized disturbance with spike-wave or polyspike-wave paroxysms which increase during photic stimulation. Myoclonic jerks incapacitate the patient. Within 5 years after the onset of the first symptoms, many patients have a disorder of gait and may become confined to bed. Sodium valproate alone or combined with clonazepam is the most effective therapy. However, the course of the disease is progressive. The mean age at death has been 24 years but appears to be increasing. The etiology and pathogenesis of PME without Lafora bodies are unknown. Increased excretion of indican has been noted, suggesting deficient intestinal absorption of L-tryptophan. A loss of Purkinje cells is the most prominent neuropathological feature. No inclusion bodies are present. Finnish PME patients are similar to the patients described by Unverricht from Estonia and by Lundborg from Sweden. Neuropathological data from these patients are not available. Clinically, these patients could form an entity with Finnish patients defined as a Baltic or Nordic type of PME. The gene is enriched in Finland, but elsewhere it is rare.
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PMID:Baltic myoclonus. 241 50

Action myoclonus, reviewed in this chapter, is the term applied to arrhythmic muscular jerking induced by voluntary movement. It is made worse by attempts at precise or coordinated movement (intention myoclonus) and may also be provoked by certain sensory stimuli. The effective stimuli for action myoclonus is probably feedback from muscle afferents, although it may be initiated by corollary discharge from motor cortex to reticular formation before or at the onset of voluntary movement. The condition is usually associated with diffuse neuronal disease such as post-hypoxic encephalopathy, uremia, and the various forms of PME, although action myoclonus may be limited to one limb in some cases of focal cerebral damage. It is caused by hyperexcitability of the sensorimotor cortex (cortical reflex myoclonus) or reticular formation (reticular reflex myoclonus), or both. No consistent pathological change has been reported in autopsied cases of action myoclonus. The underlying disorder appears to be a loss of inhibitory mechanisms involving serotonin and possibly GABA as transmitter agents. The term PME is used for the association of myoclonus with degenerative changes in the nervous system which are commonly diffuse but may predominate in certain systems. There may or may not be associated tonic-clonic seizures, other manifestations of epilepsy, or dementia. Those cases of PME associated with Lafora inclusion bodies and cerebral storage diseases can be distinguished from the system degenerations. Systems which may be involved in the latter group include cerebellodentatorubral, pyramidal, extrapyramidal, optic, auditory, posterior columns and gracile and cuneate nuclei, spinocerebellar pathways, motor neurons of cranial nerves and anterior horns, and muscle fibers. Confronted with this diversity of pathological change, it seems unnecessary to make any clinical distinction between Ramsay Hunt syndrome and Unverricht-Lundborg syndrome (Baltic myoclonus) because cerebellar signs are found in patients described under both headings. Additional systems may be involved in individuals or families who are otherwise typical. All three names could well be joined in an eponymous title (Unverricht-Lundborg-Hunt disease) or the condition simply known as the systems degeneration type of PME, as Halliday (43) suggested. The cause of the condition (or spectrum of conditions) is at present unknown. Action myoclonus usually responds to sodium valproate or clonazepam, and some individuals, particularly those with posthypoxic myoclonus, improve with the administration of serotonin precursors.
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PMID:Action myoclonus, Ramsay Hunt syndrome, and other cerebellar myoclonic syndromes. 308 Aug 51

Fifty-five consecutive cases of myoclonus owing to various etiologies were studied by conventional EEG-EMG polygraphic recordings and/or jerk-locked or back averaging. The technique of back-averaging was shown to be useful not only for detecting EEG correlates of myoclonus that are not recognizable on the routine polygraph but also for investigating the temporal and topographic relationship between the EEG activities and myoclonus. Thirteen of 17 cases of PME and related disorders, in whom back-averaging and SEP were studied, were shown to have both a myoclonus-related cortical spike over the contralateral central area, preceding the myoclonus of an upper extremity by 6 to 22 msec, and a giant SEP accompanied by an enhanced C reflex. In these cases of "cortical reflex myoclonus," the myoclonus-related spike was similar to the P25-N33 components of the giant SEP in its wave form, scalp topography, temporal relationship to myoclonus or to C reflex, succeeding cortical excitability, and drug effect. All of this suggests participation of common physiological mechanisms in those two activities. In two cases of PME, in which myoclonus involved bilateral proximal muscles synchronously, the myoclonus-related spike was maximal near the vertex, and there was no giant SEP. The significance of this subgroup remains undetermined. In six cases of the PME group, back-averaging was inapplicable because of rare occurrence of myoclonus, but they showed a typical giant SEP accompanied by an enhanced C reflex. In CJD, back-averaging demonstrated a sharp wave or PSD over the contralateral hemisphere, preceding the myoclonus by 50 to 85 msec. This form of myoclonus seems to be subcortical in origin. In essential myoclonus and oculopalatal-somatic myoclonus, there was neither myoclonus-related cortical spike nor giant SEP. Electrical stimulation of the peripheral nerve at variable intervals after the myoclonus onset (jerk-locked-SEP paradigm) was shown to be useful for investigating the influence of myoclonus on cortical excitability.
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PMID:Electroencephalographic correlates of myoclonus. 308 Aug 53

Eleven patients with long-standing progressive myoclonus epilepsy, PME, and age- and sex-matched epileptic controls received L-tryptophan (L-Trp) 100 mg/kg body weight combined with carbidopa in addition to their usual anticonvulsant regimen. During six weeks of the trial an improvement in activities of daily living and a decrease of action myoclonus was noted in the PME patients. The frequency of seizures compared with the past year decreased significantly in the PME patients, but not in the epileptic controls. Changes in the EEGs of the PME patients were scant, but a slight decrease was noted in myoclonic spikes. Both plasma Trp and platelet 5-HT increased significantly and at least as much as in epileptic controls. 5-HIAA and HVA concentrations in the CSF of the PME patients increased significantly during the trial. The results support previous findings concerning Trp treatment in PME, and longer trials with Trp + carbidopa could be of value in this disease.
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PMID:L-tryptophan-carbidopa trial in patients with long-standing progressive myoclonus epilepsy. 617 51

A boy of Finnish descent developed nerve deafness at six years of age, action myoclonus two years later, generalized myoclonic seizures when 16 years old and muscular atrophy at the age of 17 years. Bulbar palsy caused his death from inhalational pneumonia when he was 19 years old. Autopsy disclosed no significant changes in the cerebral cortex, thalamus, striatum, Purkinje cells or dentate nucleus. The most striking histological finding was degeneration of motor neurones in cranial nerves and anterior horns of the spinal cord, with neuroaxonal dystrophy of nucleus gracilis and cuneatus. While nerve deafness and spinal muscular atrophy have been recorded (each in different families) in association with progressive myoclonic epilepsy, the combination of these features has not previously been reported. Reasons are put forward for regarding all the system degenerations found in PME, including Unverricht-Lundborg disease (Baltic myoclonus) and the Ramsay Hunt syndrome, as variations of the same disorder.
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PMID:Progressive myoclonic epilepsy, nerve deafness and spinal muscular atrophy. 643 45

Dentatorubral-pallidoluysian atrophy (DRPLA) is a rare autosomal dominant neurodegenerative disorder characterized clinically by various combinations of myoclonus, epilepsy, cerebellar ataxia, choreoathetosis, dementia and psychiatric symptoms. Based on the phenomenon of anticipation, the gene for DRPLA was recently identified. DRPLA is caused by unstable expansion of a CAG repeat in the gene located on the short arm of chromosome 12. As have been observed in Huntington's disease and SCA1, there is a strong correlation between the age of onset and the size of CAG repeats. Furthermore, patients with larger repeats tend to show a PME (progressive myoclonus epilepsy) phenotype as well as earlier ages of onset. More prominent anticipation and larger intergenerational increase of CAG repeats in paternal transmission can be accounted for by the meiotic instability of CAG repeats in male gametogenesis. Comparison of size distributions of CAG repeats in Japanese, African-American and white populations revealed that 7.4% of the Japanese alleles had greater than 19 repeats, whereas none of the whites and 1% of the African-American alleles were of this size. The results may account for the ethnic predilection of DRPLA.
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PMID:Dentatorubral-pallidoluysian atrophy (DRPLA). Molecular basis for wide clinical features of DRPLA. 761 90

Since age 12 years, a 25-year-old woman had a syndrome with myoclonic epilepsy, cerebellar signs, and spontaneous myoclonus. Skin biopsy showed typical Lafora bodies (LB), but she lacked a progressive course and mental impairment, hallmarks of Lafora disease. Lysosomal enzyme assays showed low level arylsulfatase A (ASA) activity. DNA study disclosed a homozygous ASA Pd genotype. Both parents carried one Pd allele. The still-unknown relationship between the pathologic level of ASA activity and myoclonic epilepsies suggests introduction of ASA assays in patients with PME.
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PMID:Arylsulfatase A pseudodeficiency and Lafora bodies in a patient with progressive myoclonic epilepsy. 790 74

The finding of increased activity of the enzyme extracellular superoxide dismutase in four siblings with progressive myoclonus epilepsy of the Unverricht-Lundborg type (PME-UL) prompted the addition of antioxidants to these patients' treatment regimen. After 6 months treatment with vitamin E, selenium, riboflavin, and zinc, there was some improvement in patient awareness and speech. N-acetylcysteine (NAC) is a sulfhydryl antioxidant that increases cellular glutathione and the activity levels of several antioxidant enzymes and has additional actions that contribute to its demonstrated efficacy in preventing or decreasing damage in models of neuronal toxicity. We treated the affected siblings with 4 to 6 grams a day of NAC in addition to the other antioxidants and magnesium. There has been a marked decrease in myoclonus and some normalization of somatosensory evoked potentials with NAC treatment. The patients were treated with NAC for up to 30 months with continued beneficial effects. NAC may prevent further deterioration in the clinical course of patients with PME-UL and may be indicated in other neurodegenerative conditions where excess free radical activity may contribute to disease progression.
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PMID:Treatment of four siblings with progressive myoclonus epilepsy of the Unverricht-Lundborg type with N-acetylcysteine. 890 41

We report an 11-year-old boy with a non-photosensitive epileptic self-induced seizures, pacygyria and familial ataxia. His grandmother and aunts had dysarthria, and his mother had developed progressive ataxia and myoclonus since 40 years old. His older sister had ataxia, mental retardation and epilepsy. As for the boy, motor developmental delay with muscle hypertonicity of left extremities was recognized at the age of 5 months. Mental retardation and ataxia was recognized at the age of 3 years and slight mental regression is recognized at the age of 11 years. No special findings were detected in an examination of his blood and cerebrospinal fluid, including amino acids, lysosomal enzymes activity and genetic analysis for dentatorubralpallidoluysian atrophy. Brain magnetic resonance imaging revealed pachygyria of the right cerebral cortecies. At the age of two, he began to induce seizures with impairment of consciousness in himself by waving his right hand over his face which was directed toward a source of bright light. At the age of seven, he developed spontaneous seizures with impairment of consciousness. An EEG showed frequent spikes in the occipital areas, on the right and left sides occurring either independently or synchronously. Intermittent photic stimulation and pattern stimulation did not induce a paroxysmal discharge in EEG. Ictal EEG suggested that the origin of the seizures was the occipital lobe. Treatment with valporate and zonisamide was effective in reducing the seizures. The findings of our case imply the pathogenesis of self-induced seizures and the relationship between PME and neuronal migration disorders.
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PMID:[A case of non-photosensitive, self-induced epileptic seizures with pacygyria]. 978 Jul 45


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