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)

ENM is an etiologically heterogeneous disorder clinically evident as brief (less than 500 msec) lapses of tonic muscular contraction which seems to be related to lesions or dysfunction of different anatomofunctional levels of the CNS (Fig. 13). ENM can occur in heterogeneous epileptic disorders, ranging from benign syndromic conditions (such as BECTS) to focal static lesional epilepsy, as in neuronal migration disorders, and even to severe static or progressive myoclonic encephalopathies (PMEs). Neurophysiological studies in patients with ENM lead to the following conclusions: 1. A cortical origin of ENM is supported by EEG mapping and dipole analysis of spikes related to the ENM. In particular, our data suggest that the focal spike is a paroxysmal event involving, primarily or secondarily, the centroparietal and frontal "supplementary" motor areas. 2. A cortical inhibitory active mechanism for the genesis of ENM is supported by the occurrence of a decreased motor response to TMS, with preserved spinal excitability as demonstrated by the persistence of F waves. A "cortical motor outflow inhibition" related to spike-and-wave discharges was suggested by Gloor in his Lennox lecture (34). The cortical reflex negative myoclonus, described by Shibasaki et al. (16) in PME, is also consistent with a cortical active inhibitory mechanism. The spike associated with ENM raises new issues about the definition of "interictal" versus "ictal" EEG paroxysmal activity. A single spike on the EEG can be clinically silent (therefore, "interictal") or clinically evident as ENM (then viewed as "ictal"), depending on whether a given group of muscles is at rest or is showing tonic activity (see Fig. 4). These data, from a more general perspective, imply that the motor manifestation related to EEG paroxysmal events can depend not only on amplitude, topography, or intracortical distribution of seizure activity (35), but also on plasticity (36) and on the functional condition of the motor system (37). The variability of latency between the spike and the onset of the muscular inhibition (ranging from 15 to 50 msec, for the upper limbs), and the variability of duration of the ENM itself (from 50 to 400, or more, msec) indicate that ENM could be the result of inhibitory phenomena arising not only from a single cortical "inhibitory" area, but also from subcortical and pontine structures, as discussed by Mori et al. (this volume). The neurophysiological distinction between ENM and postmyoclonic periods of muscular suppression, mainly related to an EGG slow wave, as described by Lance and Adams (2) in the postanoxic action myoclonus is still a matter of discussion (38, 39). This is also the case for other movement disorders combining action myoclonus and epilepsy-as described in Ramsay Hunt syndrome (30), now better referred to as Unverricht-Lundborg syndrome (40) (Fig. 14). In these conditions, myoclonia and muscular silent periods are inconstantly associated with paroxysmal EEG discharges, suggesting a possible thalamocortical mechanism rather than a purely cortical one. In the most prolonged muscular inhibitions, both cortical and thalamocortical mechanisms might be implicated. Clearly, our knowledge of ENM is still very limited and gaining further insights into this complex phenomenon is a challenging problem.
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PMID:Epileptic negative myoclonus. 884 69

The goal of this review is to assess the value of treating versus not treating benign epilepsy (of childhood) with centrotemporal spikes (BECTS). Among 110 recommendations from 96 articles, two-thirds generally favored and one-third generally did not favor treatment with antiepileptic drugs (AEDs). Two studies concluded that all patients should be treated, but most investigators added qualifications, for example, treating those with early onset, multiple seizures at onset, and large numbers of seizures, especially generalized tonic-clonic seizures, and limiting treatment to 1 year. Other studies made treatment dependent on epileptiform discharges or amelioration of symptoms. Specific AEDs were reviewed, and in the largest number of positive studies, valproic acid or carbamazepine was favored. Among the studies generally opposing treatment, none opposed treatment for all patients in all circumstances. Usually, qualifications to treat were added, for example, if generalized tonic-clonic seizures occurred or if there was a change in quality of life. One AED associated with negative effects was carbamazepine, treatment with which can result in the development of epileptic negative myoclonus, absence seizures, and generalized spike-wave complexes on the EEG. Thus, if treatment is planned, valproic acid may be considered the drug of choice in BECTS. Although many neurologists oppose treatment; twice as many studies concluded in favor of treatment. The typical benign aspect of this disorder may allow for nontreatment to be without serious consequences.
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PMID:Benign epilepsy of childhood with centrotemporal spikes (BECTS): to treat or not to treat, that is the question. 2127 34