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)

A 14-year-old female with epilepsia partialis continua was explored stereo-electroencephalographically (SEEG). SEEG, EEG and EMG were recorded synchronously on a 32-channel machine and stored on magnetic tape for off-line analysis. The beginning of the myoclonus was used as trigger for the analysis of the intracerebral activity, which was analysed by averaging. Thereby the generating potentials of the jerks became evident. They had different maxima and latencies relative to the facial and hand muscles: that for m. orbicularis oculi was located in the precentral gyrus, the beginning of its positive deflection was 17 msec earlier than the muscle action potential; that for the thenar muscles had a latency of 24 msec, appeared at first in the premotor cortex and with a slight delay, but with greater amplitude in the corona radiata and capsula interna. Stimulation of the lateral area 4 elicited myoclonus which corresponded to the spontaneous one in distribution and latency. Stimulation of the thalamic VL nucleus had no effect. During deep sleep the frequency of the myoclonus was diminished. REM sleep was preceded and followed by a definite increase of jerking. The pattern, topography and latency of the generating potentials in waking and sleeping were very similar. In this way quantitative evidence of the neocortical origin of Epc is given and therefore a precise delineation of the epileptogenic focus.
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PMID:Quantitative analysis of intracerebral recordings in epilepsia partialis continua. 7 22

Report is made of two patients with Epilepsia Partialis Continua (E.P.C.) from brain organic damage (since carcinoma metastasis and localized ischemia). Clinical EEG, neuroradiological and anatomo-pathological and therapeutical problems are dealth with the light of a review on previous papers. The EEG by itself is assumed as a not sufficient neurophysiological mean. Long time poligraphic enregistrations during awakeness and sleep havae, on the contrary, produced interesting data. The continuous and localized more or less rhythmic myoclonus, which are the distinctive feature in the E.P.C., were in both the patients confined to the first two fingers of their hands; the more they decreased the deeper was sleep (phase II and III-IV) and almost disappeared in the REM phase. Thus poligraphic enregistrations for E.P.C. patients are maintained as very significant.
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PMID:[Poligraphy during awakeness and sleep in patients with epilepsia partialis continua]. 12 64

Tonic and rhythmic activity of the masticatory muscles accompanied by a loud and grating or clicking sound characterizes bruxism, a well-recognized parasomnia. We describe a 63-year-old man who complained of insomnia due to repeated tongue nibbling during sleep. Nocturnal polysomnographic recordings showed brief (50-100-ms) myoclonic jerks of myloioideus and masseter muscles occurring during phase 1 of sleep and leading to troublesome tongue nibbling with arousal of the patient. Hypnograms showed reduction of phase 2 and absent phases 3-4 and REM. Different pharmacological treatments including clomipramine, benzodiazepines, and carbamazepine were ineffective. A purposive interdental plate was placed to prevent jaw closings during sleep: masticatory myoclonus still persisted, but it did not provoke arousals; insomnia disappeared and night hypnograms improved.
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PMID:Sleep-induced masticatory myoclonus: a rare parasomnia associated with insomnia. 181 24

Ten patients with involuntary leg movements due to myelopathy were studied clinically and polysomnographically. The clinical manifestation and polysomnographical findings of involuntary leg movements were identical to sleep-related periodic leg movement (PLM) (nocturnal myoclonus). Since 2 patients had complete transection of spinal cord due to injury or vascular accident, the spinal cord deprived of supraspinal influences was considered to generate the rhythm of PLM. Suppression of the leg movements during REM sleep was not obvious in the patients with complete transection of spinal cord. In addition, PLM alternated from one side to the other 1-4 times a night with intervals of 1-4 h in all patients. This alternation also seemed to be from the spinal cord. This PLM of spinal cord origin was different from spinal myoclonus in their clinical features although both were generated within the spinal cord. PLM of spinal cord origin showed a triple flexion of the ankle, knee and hip, and this was very similar to a flexor withdrawal reflex which all patients exhibited. Therefore, it was suggested that PLM of spinal cord origin has a common mechanisms with spinal automatism. Although all patients had extensor plantar responses, PLM preceded the paresis in three patients and the severity of paresis was variable. There was no laterality of left and right PLMs even in patients with weakness of the leg on one side. This suggested that PLM of spinal cord origin might be induced by the interruption of the tract which was separate from, but runs near the corticospinal tract.
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PMID:Sleep-related periodic leg movements (nocturnal myoclonus) due to spinal cord lesion. 191 96

Among progressive myoclonus epilepsies (PME), the nosography of the Ramsay Hunt syndrome (RHS) has been much debated. The authors report on a homogeneous group of 43 patients originating from around the western Mediterranean, with a large number of northern African subjects, who were followed up for a mean period of 11.6 years. Onset is between 6 and 17 years (mean: 11.2) and the transmission appears to be recessive. The clinical features include: action myoclonus, generalized epileptic seizures, mild cerebellar signs and lack of dementia. EEG features include normal background activity, spontaneous fast generalized spike-wave discharges, photosensitivity, lack of activation during nREM sleep and vertex/rolandic spikes during REM sleep. The prognosis is variable, even within families, but the progression seems to be slow in a majority of patients. This condition can be distinguished from mitochondrial encephalomyopathy and is less severe than Baltic myoclonus. The authors propose that this form of PME, formerly reported as RHS, be more properly described as Mediterranean myoclonus.
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PMID:The Ramsay Hunt syndrome revisited: Mediterranean myoclonus versus mitochondrial encephalomyopathy with ragged-red fibers and Baltic myoclonus. 210 22

Polysomnography, including electroencephalography, electromyography and electro-oculography was performed in three patients with palatal myoclonus (PM). The amplitude of the myoclonus decreased during sleep. The frequency did not change during non-REM sleep, but increased during REM sleep in two patients. Ocular myoclonus synchronized with PM disappeared during deep sleep stages in two patients and reappeared during REM sleep in one of them. In the other patient, ocular myoclonus was noted only in REM sleep, being absent even when the patient was awake. All patients showed episodic EEG activities synchronous with myoclonic jerks only in REM sleep. These episodes were noted 5-15 times throughout the night, and each episode lasting for 1-7 s. They were negative or positive waves of saw-tooth appearance which were distributed predominantly in the central region. During the episodes, the frequency of myoclonic jerks increased in two patients. Although it is known that REM sleep influences PM and ocular myoclonus, this is the first report demonstrating the electroencephalographic activity associated with PM.
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PMID:Electroencephalographic activity related to palatal myoclonus in REM sleep. 223 Aug 42

The spatial and temporal EEG features of the epileptogenic syndrome induced by cessation of chronic intracortical GABA infusion in normal rats are described. In the initial stages, the paroxysmal discharges (PDs) induced by withdrawal from unilateral GABA application may appear either unilaterally or bilaterally, although with greater amplitude on the infused side. PDs are transitorily accompanied by behavioral signs of distal myoclonus of the body territory corresponding to the infused area (contralateral hindlimb). Later, the paroxysmal activity becomes more localized, circumscribed to the cannula-infused site and with ipsilateral propagation to anterior cortical areas. The amplitude of PDs decreases progressively while their frequency increases, reaching its maximal value at about 4 h after the first PDs have appeared. In the final stages of the syndrome, which may last several days, clinical manifestations are absent and PDs are activated by slow-wave sleep and reduced during REM sleep and waking. Chronic intracortical applications of taurine failed to induce any electroclinical changes on withdrawal and were unable to inhibit the focus elicited by GABA withdrawal, whereas reinstatement of GABA infusion into the epileptogenic area was effective in blocking the paroxysmal activity. Intracortical infusion of baclofen induced the appearance of an epileptogenic focus that waned on withdrawal. The GABA-withdrawal syndrome appears to be a new model of focal status epilepticus; it may be useful as an experimental model of human partial epilepsy to investigate the role of GABAergic neurotransmission.
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PMID:Electroencephalographic study of the GABA-withdrawal syndrome in rats. 236 74

Physiological hypnic myoclonus (PHM) was quantified during wakefulness and sleep in 7 normal subjects. PHM was evident during relaxed wakefulness and increased during stage 1 and especially REM sleep. In some muscles, however, (e.g., soleus) it showed no increase during sleep. PHM resembled simple fasciculation potentials, or, when repeated or in clusters, the fragmentary myoclonus in NREM sleep. Both 'hypnic' and 'myoclonus' are terms inappropriate to the description of this physiological spontaneous motor activity.
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PMID:Physiological hypnic myoclonus. 245 94

REM sleep is the most antiepileptic state in the sleep-wake cycle for human generalized epilepsy, yet the neural mechanism is unknown. This study verified the antiepileptic properties of REM sleep in feline generalized epilepsy and also isolated the responsible factors. Conclusions are based on 20 cats evaluated for generalized EEG and motor seizure susceptibility before and after dissociation of specific REM sleep components. Bilateral electrolytic lesions of the medial-lateral pontine tegmentum created a syndrome of REM sleep without atonia. Systemic atropine created a syndrome of REM sleep without thalamocortical EEG desynchronization. Identical results were obtained in two seizure models, systemic penicillin epilepsy and electroconvulsive shock. (1) Normal REM sleep retarded the spread of EEG seizure discharges and had even more potent anticonvulsant effects. (2) Selective loss of 'sleep paralysis' (skeletal muscle atonia) during REM abolished REM sleep protection against myoclonus and convulsions without affecting generalized EEG paroxysms. (3) Conversely, selective loss of thalamocortical EEG desychronization abolished REM sleep protection against generalized EEG seizures without affecting clinical motor accompaniment. These results suggest that the descending brainstem pathways which mediate lower motor neuron inhibition also protect against generalized motor seizures during REM sleep. Protection against spread of EEG paroxysms is governed by a separate mechanism, presumably the ascending brainstem pathways mediating intense thalamocortical EEG desynchronization during REM sleep.
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PMID:Mechanisms of seizure suppression during rapid-eye-movement (REM) sleep in cats. 259 45

Thirteen patients with dyssynergia cerebellaris myoclonica (Ramsay Hunt syndrome) had full clinical and neurophysiological study as well as muscle biopsy. The patients had action myoclonus, generalised epileptic seizures, and mild cerebellar syndrome. The disease was inherited in an autosomal recessive pattern in five patients, and occurred as isolated cases in the remaining eight patients. The age at onset of symptoms ranged from 6 to 15 years (mean, 10.4 years). The EEG and polygraphic findings included normal background activity in most patients, spontaneous fast generalised spike-and-wave discharges, photosensitivity, no activation during slow sleep, and vertex and rolandic spikes in REM sleep. Results of muscle biopsy, performed an average of 14 years after onset of the disease, were normal and showed no mitochondrial abnormalities. These findings suggest that Ramsay Hunt syndrome is a condition with distinctive clinical and neurophysiological features and unrelated to mitochondrial encephalomyopathies.
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PMID:Dyssynergia cerebellaris myoclonica (Ramsay Hunt syndrome): a condition unrelated to mitochondrial encephalomyopathies. 210 13


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