Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027066 (myoclonus)
 4,275 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Twelve patients with benign juvenile myoclonic epilepsy (BJME) representing 4% of our population of epileptics (n = 275) are presented. Only two patients (17%) had myoclonic jerks as the only seizure type. Seven (58%) had generalized tonic-clonic seizures (GTCS) and myoclonus. Three patients (25%) had absence seizures (AS), GTCS, and myoclonic jerks. Electroencephalographic evidence of photosensitivity was found in four (33%). Auditory precipitation of seizures was found in one patient. As is the case with other primary generalized epilepsies, the onset of BJME seems to be age specific. In our series the mean age of onset in years was 4.3 for AS, 14.75 for myoclonic jerks, and 16.4 for GTCS. It took an average of 8.5 years from the onset of BJME (range, 2-20 years) and 6.5 years from the onset of GTCS (range, 2 months-6 years) until the condition was properly recognized. Five patients experienced at least one episode of myoclonic status epilepticus. Generalized, paroxysmal, symmetric polyspike and slow wave discharges are the typical EEG finding. These complexes, however, showed considerable interpatient variability. Sleep deprivation proved to be the most valuable activating procedure. Valproic acid monotherapy effectively controlled myoclonic jerks as well as associated GTCS in most patients.
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PMID:Some clinical and EEG aspects of benign juvenile myoclonic epilepsy. 642 Jan 45

Suriclone (SC) is a new anxiolytic compound with a chemical structure different from that of benzodiazepines (BZD) but SC possesses a high affinity for the so-called BZD receptors. SC was tested in the naturally or the allylglycine-treated photosensitive baboon Papio papio. As active BZD administered by the intramuscular or oral route, this new compound possesses a marked protective effect against the excessive photosensitivity of the baboons, it blocks myoclonus following EEG spike and waves discharges induced by intermittent light stimulation; as BZD again, SC can induce spontaneous myoclonus not accompanied by EEG spike and wave discharges.
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PMID:Action of suriclone in naturally and allyglycine-induced photosensitive baboons, Papio papio. 643 48

A 23-year-old man presented with a history characterized by a myoclonic syndrome developing over a period of seven years. Predominant symptoms were intention and activity myoclonus, generalized epileptic seizures occurring infrequently from the age of 20, a slowly progressive cerebellar syndrome first apparent at 19 years, and the sudden onset of loss of visual acuity at 19, which then partially regressed; optic atrophy and clinical and campimetric signs were suggestive of Leber's disease. Intellectual ability was not affected. E.E.G. records showed generalized spike-waves with photosensitivity, progressive reduction in basal rhythm, and sleep organization disturbances with focal abnormalities. Obvious clinical signs of muscle disease were lacking but muscle biopsy confirmed the presence of a mitochondrial myopathy (ragged-red fibers). An indefinite history of familial neurological disease was obtained. Diagnosis was established as myoclonic cerebellar dyssynergy with spastic hereditary ataxia and Leber's disease. Their association with a mitochondrial myopathy has been previously reported by Tsairis et al, Fukuhara et al, Fitzimons et al (familial case), and Niedermeyer et al (sporadic case). In spite of the non-specific nature of associated mitochondrial abnormalities, all these cases would appear to correspond to a single nosological entity.
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PMID:[Spinocerebellar degeneration, optic atrophy, epilepsy, myoclonus and mitochondrial myopathy: a case report (author's transl)]. 681 Apr 37

Out of a group of 12 M. nemestrina (originating from Malaysia), 9 adults had shown clinical signs induced by ILS at 25 c/sec. Six of them (3 males, 3 females) were very photosensitive; however, only 2 presented eyelid and/or head jerks after the end of ILS (level 4), but never a generalized seizure. Tactile periorbital stimuli favoured myoclonus. In all but the two of level 4, the intensity of clinical signs varied from one day to the next. In all implanted adult macaques, spontaneous paroxysmal EEG activities were seen during slow sleep in mostly anterior areas, but also during waking and REM sleep in some of them; however, their occurrence depended upon the individual and were not in all cases related to their level of photosensitivity. During ILS, paroxysmal discharges (spikes and waves and/or polyspikes and waves), isolated or in bursts at 3-4/sec were bilateral and symmetrical. They started in fronto-rolandic regions, then became generalized. This observation constitutes a new fact since the discovery, in 1966, of the photomyoclonic syndrome of Papio papio, Macaca nemestrina being another species of subhuman primates with a marked predisposition to photosensitive epilepsy.
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PMID:[Observation of a photosensitive syndrome in Macaca nemestrina (author's transl)]. 732 74

We made a long term prospective study of 66 patients with juvenile myoclonic epilepsy (JME). Prevalence was 10.2% among 672 patients with epilepsies. Sex distribution was equal. Sixty-three were not diagnosed on referral; JME was not initially recognized in the epilepsy clinic in 22. Clinical typical absence seizures were reported in 33.3%, myoclonic jerks in 97% and generalized tonic-clonic seizures (GTC) in 78.8% of the patients. Mean age (+/- SD) at onset was 10.5 +/- 3.4 years (range 5-16 years) for absence seizures, 15 +/- 3.5 years (range 8-26 years) for myoclonic jerks, and 16 +/- 3.5 years (9-28) years (range 1-9 years) and GTC by 4.4 +/- 2.7 years (range 1-8 years) in 14 (21.2%) patients who manifested all three types of seizure. Absence were never antedated by myoclonic jerks or GTC. Myoclonic jerks occurred on awakening in 87.5% of the patients. GTC occurred mainly on awakening, but other patients had nocturnal or diurnal GTC with no circadian distribution. Neurologic examination was normal for all patients except for tremor of the hands similar to essential tremor, noted in 35% of patients. Computed tomography (CT) brain scans were normal: 93% of patients had precipitating factors: sleep deprivation (89.5%), fatigue (73.7%), photosensitivity (36.8%; television and video games 8.8%), menstruation (24.1% of women), mental concentration (22.8%), and stress (12.3%). Incidence of JME among siblings (13 of 41 examined families) implies an autosomal recessive mode of inheritance for this Arab population. EEGs were frequently normal in treated patients. At least one abnormal EEG was recorded in 56 (84.9%) patients. Abnormalities consisted mainly of generalized discharges of spike/double spike and/or polyspike and slow wave. Frequent multiple spikes and discharge fragmentations varied from 0.5- to 20-s duration (mean 6.8 s). Twenty (30.3%) had focal abnormalities, and 18 (27.3%) had photoconvulsive discharges. Eighty-eight percent of patients remained seizure-free for > or = 3 years of follow-up. Effective treatment was achieved with valproate (VPA); control of myoclonic jerks was improved with clonazepam (CZP). CZP monotherapy did not consistently prevent GTC. Adding small doses of CZP with simultaneous reduction of VPA was the most effective and better tolerated form of medication, particularly in patients demonstrating an adverse reaction or requiring a large VPA dosage. VPA dosage was successfully reduced in 15 patients who were seizure-free for > 2 years and had infrequent seizures before treatment, but 9 of 11 patients relapsed after VPA discontinuation.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Juvenile myoclonic epilepsy: a 5-year prospective study. 815 46

We performed a 5-year clinical and electrophysiologic follow-up study on two sibling cases with myoclonus epilepsy with ragged-red fibers. Both had myoclonus, intention tremor, slight muscle weakness, slight mental disturbance, hearing impairment, and optic atrophy. Neither had epileptic attacks or truncal or gait ataxia. Biochemical activity of cytochrome c oxidase was at the lower limit of the normal range of values, and an adenine to guanine transition mutation at nucleotide 8344 in the transfer RNA specific for lysine of mitochondrial DNA was detected in both cases. The electroencephalograms showed slowing of basic patterns, diffuse spike-and-wave complexes, occipital dominant wave-and-spike phantoms, 6- and 14-Hz positive spikes, and photosensitivity. No definite deterioration of basic patterns was seen, and diffuse spike-and-wave complexes and photosensitivity gradually disappeared during the slowly progressive clinical course. P2 latencies of pattern-reversal visual evoked potentials throughout the clinical course and III through V interpeak latencies of auditory brainstem responses at follow-up were prolonged without giant sensory evoked potentials in both cases.
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PMID:Myoclonus epilepsy with ragged-red fibers: a clinical and electrophysiologic follow-up study on two sibling cases. 822 33

Twenty-one cases (12 males, 9 females) of Lafora's disease in 16 families were studied at the National Institute of Mental Health and Neuro Sciences (NIMHANS), Bangalore, India, from 1982 to 1990. Mean age of onset was 13.5 years (range 9.5-18 years). First symptom was generalized tonic-clonic seizure (17), myoclonus (3), or dementia (1). All patients eventually developed the classical triad, except 1 who has had only myoclonus. Seven had occipital seizures. Other signs included behavioral changes (9), brisk tendon reflexes (11), cerebellar signs (8), and visual impairment (4). Patients from 14 of the 16 families (85%) were products of consanguineous marriage. More than 1 sibling was affected in 6 families. Scalp EEGs showed diffuse background slowing with epileptiform discharges in all and progressive slowing as the disease progressed in 3. Photosensitivity occurred in 4 of the 17 cases studied (23.5%). EEG abnormalities were documented in the presymptomatic stage in 2 cases 6 months and 6 years before clinical symptom onset. Visual evoked responses were abnormal in 4 of the 6 cases studied. Giant somatosensory evoked potentials (SSEP) were observed in all 8 cases studied. Lafora bodies were demonstrated in axillary skin in 14 of 17 (82.4%), in liver in 4 of 10 (40%), and in both brain biopsy specimens. In 2 cases, liver biopsy was positive while axillary skin biopsy was negative. In the brain, inclusions were evident in glial and capillary endothelial cells in addition to neurons. Although our cases were similar to those described earlier, the relative rarity of visual phenomena is emphasized. The clinical pattern was consistent with autosomal recessive inheritance. The high frequency of consanguinity in the South Indian population may be responsible for the many cases observed at our center.
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PMID:Lafora's disease in south India: a clinical, electrophysiologic, and pathologic study. 838 90

We present the first documented case of photic-induced epileptic negative myoclonus. A 17-year-old girl had experienced two generalized tonic-clonic seizures (GTCS) while watching television. The only EEG abnormality was a photoparoxysmal response (PPR), which was sometimes accompanied by loss of postural tone in both arms. Valproate was effective in abolishing photosensitivity. Negative myoclonus should be included among the ictal phenomena accompanying PPR.
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PMID:Photic-induced epileptic negative myoclonus: a case report. 861 79

Primary Generalized Epilepsy (PGE) has been more hotly debated over the past decades than other forms of epileptic seizure disorder. The sudden synchronous appearance of bilateral spikes and spike-waves (mainly with myoclonus resp. absence) used to perplex the earliest generation of electroencephalographers, and the enigmatic genesis of these discharges (and seizures) has not ceased to fascinate the investigators of this phenomenon. A "centrencephalic" concept with paroxysmal discharges arising from thalamic structures and "projecting" to the cortex was championed for many years and eventually laid aside. More recently, the role of the thalamic level has been re-emphasized, mainly on the basis of experimental work. In this article, the bulk of experimental work is critically reviewed: the simian model (Papio papio), the feline, and the rodent models (Wistar rat, tottering mouse). Stress is being laid on fundamental differences between all of these models and human PGE. EEG evidence indicates a superior frontal origin of bilateral-synchronous spikes and spike-waves; depth EEG recordings in patients have failed to demonstrate primary thalamic spike generation. The heart of the matter in PGE appears to be the mechanism underlying paroxysmal discharges; above all the role of arousal. It is not awakening from sleep but the ensuing period that is critical in its epileptogenic thrust caused by alternating periods of return to drowsiness and arousing stimuli. This biphasic process gradually escalates EEG bursts to myoclonus (or absences) and possibly to a generalized tonic-clonic convulsion. Most conducive to this crescendo is the state of tiredness following a night of poor sleep. Bilateral synchrony is not precise and small time differences exist. The line between primary and secondary bilateral synchrony (with a primary cortical focus) can become blurred. Genetic predisposition to generalized paroxysms must always be considered, even in the face of a primary focus with secondary bilateral synchrony. Photosensitivity is a second paroxysm-inducing mechanism in PGE; it is much less common than the abnormal arousal ("dyshormia"); both mechanisms can be present in the same patient. Therapy and prevention of seizures in PGE are finally discussed. The concept of abnormal arousal mechanisms can be put into practice in order to prevent seizures: avoidance of sleepless nights, not always an easy task in adolescents and young adults.
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PMID:Primary (idiopathic) generalized epilepsy and underlying mechanisms. 871 97

The experimental antiepileptic drug, levetiracetam (UCB L059), a piracetam analogue has been investigated in photosensitive patients in the "photosensitivity model", an early phase II study. A total of 12 patients (10 females, 2 males) with a mean age of 21.5 years (range 13-38) were investigated during a 3 day period in 3 centres (France, The Netherlands, Germany), using the same standardised method. The subjects were either treated with a single oral dose of 250 mg, 500 mg, 750 mg or 1,000 mg. In addition, 4 patients took 250 mg b.i.d. for 3-5 days, after which they were re-examined. In 9 of 12 photosensitive patients (75%) a clear suppression (3 patients) or abolishment (6 patients) of IPS evoked photoparoxysmal EEG responses was found. This effect appeared to be dose-dependent, the higher the dose the greater the effect; complete abolishment was only seen at dosages of 750 mg and 1,000 mg, occurring at peak plasma levels and lasting between 6 and 30 h. There was no indication of pharmacokinetic interaction with concomitant antiepileptic drugs such as valproic acid, ethosuximide or phenobarbitone. No serious side-effects were seen and some patients reported enhancement of their mood. Two patients with myoclonic jerks noticed a clear reduction of their myoclonus, although this was not one of the objectives of the study. In conclusion, levetiracetam showed a clear antiepileptic effect in the photosensitivity model.
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PMID:Photosensitive epilepsy: a model to study the effects of antiepileptic drugs. Evaluation of the piracetam analogue, levetiracetam. 895 20


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