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

Physiological and pharmacological studies of more than 150 patients with movement disorders are reported. Particular attention is paid to the differentiation of various types of tremor on the basis of rate, rhythm, and pattern of EMG activity in antagonistic muscles. The typical 'tremor-at-rest' of Parkinson's disease--3-7 Hz activity which alternates between antagonistic muscles--is suppressed, at least briefly, during voluntary activity, at which time typical 8--12 Hz 'physiological tremor' may be seen. Essential tremor and its familial or senile variants also have a characteristic EMG pattern during voluntary activity--5-8 Hz bursts of activity which are synchronous in antagonistic muscles. This type of tremor may also be present in patients with Parkinson's disease and in certain kinships with a Charcot-Marie-Tooth polyneuropathy. Other tremors in association with polyneuropathy ('neuropathic tremor') have different physiological characteristics. Myoclonus is of essentially two types ('positive' with EMG bursts and 'negative' with brief pauses in ongoing activity, as with asterixis) and may, at times, mimic tremor. Certain specific tremors respond predictably to specific pharmacological therapy.
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PMID:Physiological and pharmacological aids in the differential diagnosis of tremor. 0 92

We postulate that palatal myoclonus after infarction of the brainstem or cerebellum, or both, is the manifestation of denervation supersensitivity secondary to lesions involving the dentatorubroolivary system. Two cases of our own and 31 from the English and French literature were analyzed in order to determine the delay between the occurrence of presumed anatomical lesions and the recognition of palatal myoclonus. The intervals varied from 2 to 49 months with the median between 10 and 11 months. The natural history of palatal myoclonus following brainstem infarction seemed consistent with the hypothesis.
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PMID:Palatal myoclonus and denervation supersensitivity in the central nervous system. 3 57

Differential effects of neuropharmacological drugs upon susceptibility to flurothyl-induced myoclonic and clonic convulsions were assessed in two selectively bred lines of mice. Dopaminergic drugs (apomorphine and haloperidol) only affected myoclonus, whereas cholinergic (pilocarpine and scopolamine), gabaergic (AOAA and bicuculline), and serotonergic (PCPA) compounds principally influenced clonus. Noradrenergic drugs (clonidine, phentolamine and sotalol), however, altered the expression of both types of seizures. The apparent differential neurohumoral modulation of myoclonus and clonus is discussed in light of previous suggestions that these behaviors have separate neural substrates.
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PMID:Differential neurohumoral modulation of myoclonic and clonic seizures. 3 68

p,p'-DDT (600 mg/kg) produces myoclonic activity in mice which can be reduced by L-5-hydroxytryptophan (L-5HTP) (200 mg/kg), H75/12 (25 mg/kg), serotonin uptake blockers and two alpha-receptor blockers, phenoxybenzamine (5 mg/kg) and trazodone (5 mg/kg). Decreasing endogenous brain serotonin by pretreatment with p-chlorophenylalanine (400 mg/kg i.p.) blocked the antimyoclonic action of all of these drugs except L-5HTP. Seven other alpha-receptor blockers (phentolamine, tolazoline, yohimbine, azapetine, aceperone, nicergoline and prazosin) potentiated the antimyoclonic activity of a small dose of L-5HTP (50 mg/kg) in this animal model. We postulate that an alpha noradrenergic inhibitory synapse may be located in the neural circuit connecting a serotonergic neuron to the final motor response (p,p'-DDT-induced myoclonus).
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PMID:DDT-induced myoclonus: serotonin and alpha noradrenergic interaction. 3 58

The response of myoclonus to oral and intravenous L-5-hydroxytryptophan (5-H.T.P.) in combination with a peripheral decarboxylase inhibitor (carbidopa) and to clonazepam has been examined in 9 patients. Moderate improvement or complete cessation of myoclonus followed treatment with one or both of these regimens in 5 patients, 1 of whom also responded to the concurrent administration of L-tryptophan and a monoamineoxidase inhibitor. The remaining 4 patients were at best only slightly improved by either 5-H.T.P. or clonazepam. The responsive group consisted of 3 patients with a history of anoxia, 1 patient with non-history of severe head injury, and 1 patient with non-progressive focal myoclonus and epilepsy. This group had low levels of 5-hydroxyindole acetic acid in the lumbar cerebrospinal fluid. It is suggested that 5-H.T.P. plus carbidopa, L-tryptophan plus a monoamine-oxidase inhibitor, and clonazepam may all act by elevating brain levels of serotonin (5-H.T.) and that some human myoclonic syndromes may be specifically related to a cerebral deficiency of 5-H.T.
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PMID:Manipulation of brain serotonin in the treatment of myoclonus. 5 Dec 40

In order to overcome various drawbacks of the conventional polygraphic study of a relationship between myoclonus and EEG, the EEG preceding and following the myoclonic jerk was simultaneously averaged by the CNV program. The subjects were 7 patients presenting with myoclonus of various kinds. The conventional polygraphs showed various paroxysmal EEG activities in 4 patients, but none of those paroxysmal activities was temporally related to myoclonus except for one case. As a result of the present averaging technique, 2 patients with cerebellar ataxia with intention myoclonus showed myoclonus-related EEG spikes or spike-and-slow-waves in the contralateral central or centroparietal region. These myoclonus-related spikes preceded the myoclonus by 10-17 msec, suggesting the presence of a discharging focus in the deep cerebral structures, rather than in the cerebral cortex, in these cases. Two other patients, one with resting myoclonus and the other with postural myoclonus, showed myoclonus-related slow waves on the contralateral hemisphere. This previously undescribed method of averaged polygraphic recording will be very useful in detecting an EEG correlate of spontaneously occurring myoclonus.
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PMID:Electroencephalographic correlates of myoclonus. 5 38

Polygraphic recordings of EEG, EMG, EKG and respiration were made on three patients with histologically verified subacute spongiform encephalopathy and one patient with anoxic encephalopathy both before and after intravenous diazepam. The records showed cyclical activity occurring about every half minute in which the EEG changes were correlated with myoclonus and cardio-respiratory changes. It is suggested that these cycles represent spontaneous cycles of arousal to which the 1/sec sharp waves are related wnd which result from the same mechanisms that produce other cyclical autonomic phenomena.
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PMID:Cyclic EEG changes in subacute spongiform and anoxic encephalopathy. 5 37

A distinct neurological syndrome in twelve chronic haemodialysis patients is described. This syndrome is currently the leading cause of death in one Denver dialysis unit. The hallmarks of this syndrome are progressive speech difficulties, mental changes, and a markedly abnormal electroencephalogram which may be present months before the clinical signs appear. Additional clinical features including seizures, myoclonus, asterixis, apraxia, focal neurological signs, and psychiatric symptoms may also be observed. Neuropathological changes are slight and non-specific. The aetiology of this syndrome is unknown but the clinical and pathological features suggest a toxic/metabolic disorder. To date, this disorder has been refractory to several therapeutic measures.
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PMID:A fatal encephalopathy in chronic haemodialysis patients. 5 86

Four patients with Whipple's disease which had responded to antibiotic therapy, later developed neurologic disease identical to that seen in patients with Whipple's disease who died without treatment. Dementia, myoclonus, ataxia, and supranuclear ophthalmoplegia were the main neurologic features. Restarting antibiotics has been followed by stabilization of disease in all four. Two have improved. In three, the previously diagnosed and treated Whipple's disease was not considered as a possible cause of the neurologic disease until the symptoms and signs were far advanced. It is advisable to periodically evaluate all patients with Whipple's disease, even after successful treatment. Signs of neurologic disease should be considered a possible recurrence of Whipple's disease and antibiotics restarted.
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PMID:Neurologic disease in patients with treated Whipple's disease. 6 1

A middle-aged man suffering from myoclonic jerks of the right arm and leg and occasional grand mal seizures was investigated electrophysiologically. The EEG showed a left central spike focus which could be activated by any stimulus which distorted the biceps, triceps or brachioradialis muscles but skin stimulation was ineffective. Electrical nerve stimulation subthreshold to the alpha motoneurone fibres evoked cortical spikes and myoclonic jerks. The evidence supports the hypothesis that the myoclonus was triggered by muscle spindle afferent fibres (Ia) which projected to an epileptogenic focus in the sensori-motor area. A marked improvement of symptoms was achieved by a combination of baclophen and dipropylacetate.
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PMID:Focal reflex epilepsy with myoclonus; electrophysiological investigation and therapeutic implications. 6 53


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