Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Forty-seven HIV-seropositive children were investigated by EEG and evoked potentials (BAEP, SEP). Twenty-three children were symptomatic (P2), 8 seropositive without symptoms (P1), and 16 children were less than 15 months of age (P0). Some of them were investigated at different stages of HIV infection. During the neonatal period, 7 newborns of drug-addicted mothers had seizures and frequent spikes and sharp waves in their EEGs. Among (P2) children 6/23 showed background slowing and 1 had rhythmic theta activity (6 with and 1 without neurological symptoms). In BAEP, bilateral prolonged interpeak latencies (IPL) were found in 1 child with severe AIDS encephalopathy. Side differences greater than or equal to 0.4 ms in IPL were seen in 2 (P2), 1 without and 1 with neurological symptoms. A late onset was seen in 2 (P1) and 4 (P2) children. Median SEPs were normal in 24/26 patients; N20/N13 amplitude ratio was reduced in 2 (P1) patients. EEG and BAEP revealed nonspecific abnormal features in HIV encephalopathy. The the progression of the disease. However, also in the symptomatic group, normal results of EEG and BAEP dominated. SEP in the symptomatic group revealed only normal values. For monitoring the effectiveness of AZT treatment in HIV encephalopathy, EEG seems to be a relevant investigation; for evoked potentials more data and experience are needed.
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PMID:EEG and evoked potentials in HIV-infected children. 162 2

Pathologically enhanced somatosensory evoked potentials (giant SEPs) were recorded in 10 patients with cortical myoclonus of various origins. With non-cephalic reference electrodes a giant frontal negativity corresponding to normal N30 was found over the contra- and ipsilateral hemispheres which was not simply a phase reversal of the well-known enhanced parietal P25. The preceding far-field P14, parietal N20 and frontal P22 were of normal size. A similar result was found when SEPs were studied during the action of etomidate, an ultrashort-acting non-barbiturate hypnotic which produced a marked increase of the parietal P25 and frontal N30 after intravenous administration. These increased components, on the other hand, were abolished when recording was repeated immediately after application of electroconvulsive shock whereas P14, N20, and P22 remained more or less unchanged in both conditions. Our results indicate that there are neuronal elements in the sensorimotor cortex which are more resistant to influences such as narcotic drugs and seizure activity than others, being highly modifiable by these alterations. It is speculated whether these highly modifiable cortical systems are those in which giant SEPs, as well as pharmacologically increased SEP components, arise.
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PMID:Frontal and parietal components of enhanced somatosensory evoked potentials: a comparison between pathological and pharmacologically induced conditions. 245 99

As with other methods long used in intensive care units (ICU) and operating rooms (OR), the goal of neuroscience ICU continuous EEG (NICU-CEEG) and evoked potential (NICU-EP) monitoring is to extend our powers of observation to detect abnormalities at a reversible stage. EEG is an appropriate monitoring tool because it is linked to cerebral metabolism, is sensitive to ischemia and hypoxemia, correlates with cerebral topography, detects neuronal dysfunction at a reversible stage, and is the best method for detecting seizure activity. When applied systematically, it can impact medical decision-making in 81% of monitored patients. It is useful in monitoring precarious cerebral perfusion at the bedside, and it has revealed that nonconvulsive seizures, undetectable otherwise, occur in 34% of NICU patients. In convulsive status epilepticus, NICU-CEEG can help avoid undertreatment and overtreatment. In comatose patients, it can provide useful prognostic information as well as detect potentially treatable causes. Traditional impediments to its application are yielding to technological advances and educational efforts. Real-time digitized EEG in particular has been a major advance. Within limits, somatosensory evoked potential monitoring (ICU-SEP) is useful in the prognosis of coma, but it is less helpful in monitoring focal cerebral ischemia. Brainstem auditory evoked potential monitoring has a relatively restricted role in the NICU but is helpful in distinguishing structural from nonstructural causes of coma and can supplement ICU-SEP in predicting outcome.
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PMID:Continuous EEG and evoked potential monitoring in the neuroscience intensive care unit. 830 43

An 11-year-old girl who had the positive-negative myoclonus and the history of the generalized tonic clonic seizure was electrophysiologically studied. She had no siblings with either myoclonus or epilepsy, and her intellectual level was normal. She had no other neurological deficits including ataxia, pyramidal and extrapyramidal signs. Surface EMG showed a brief increase in the EMG activity followed by the silent period associated with positive and negative myoclonus during sustained wrist extension. Giant SEP and C reflex (38.6 ms) following electric stimulation of the median nerve at the wrist were obtained in the resting condition and the silent period (about 180 ms) following C reflex was obtained during voluntary contraction. Jerk-locked back averaging of the EEG time-locked to the onset of the myoclonic discharge recorded from the right biceps muscle showed a cortical spike at the left central region preceding the myoclonus onset by 12.6 ms. The latency of C reflex in this case was very short compared with that of previously reported cortical reflex myoclonus. The estimated cortical delay between the arrival of the somatosensory volley and the motor cortex discharge responsible for the C reflex was -1.0 ms and this value was shorter than that in patients with typical cortical reflex myoclonus (mean 3.7 +/- 1.1 ms). Conditioning stimuli (C) of the right median nerve at the wrist started to facilitate the amplitude of the motor evoked potential recorded from the right abductor pollicis brevis muscle after magnetic test stimuli (T) of the left motor cortex at 20 ms of the C-T interval. This C-T interval was shorter than that (24.6 +/- 1.6 ms) in patients with the typical cortical myoclonus. These electrophysiological findings suggested the shorter reflex pathway of the cortical reflex myoclonus in this case than in typical cortical reflex myoclonus. We speculated that the myoclonus was based upon the direct sensory projection from the thalamus to the motor cortex in this case.
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PMID:[A case of cortical reflex positive-negative myoclonus--electrophysiological study]. 950 69

Partial motor seizures occur, followed after a variable interval by well-localized myoclonic jerks, in the patients with Kojewnikow syndrome, or epilepsia partialis continua. However, the epileptogenic focus remains to be established. We studied the epileptogenic focus of a 17-year-old boy with intractable Kojewnikow syndrome. Interictal EEG, ictal EEG, jerk-locked averaging, and ictal SPECT revealed a left central focus. A giant SEP indicated increased exitability of the primary sensory area. Magnetoencephalogram (MEG) and electrocorticogram identified the epileptogenic focus in the pre- and post-central cortex, indicating involvement of both the primary motor and sensory areas. Surgical treatment was successful. Thus, MEG proved to be the most accurate tool in the presurgical evaluation.
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PMID:[Magnetoencephalographic and electrocorticographic studies on the epileptogenic focus in a patient with Kojewnikow syndrome]. 1002 35

The pediatric epilepsy management team in the Hospital for Sick Children, Toronto, Canada, consists of neurologists, neurophysiologists, neurosurgeons, neuropyschologists, clinical nurse specialist/nurse practitioners, social workers, EEG technologists and psychiatrists. The patients are initially referred to us for the diagnosis of seizure disorders. Epileptic foci and eloquent cortices are identified by neurophysiological studies such as EEG, MEG and SEP. Epileptogenic lesions can be visualized by MRI, the language, motor and sensory cortices by fMRI and the regions of hypoperfusion and hypometabolism in the epileptic foci, by SPECT and PET, respectively. The results of these studies are then discussed by members of the team. For patients with lesional epilepsy, an intraoperative image guided system and intraoperative electrocorticography are used, when lesionectomy, lobectomy and additional multiple subpial transection (MST) are performed. Patients without an identifiable lesion require intracranial invasive video EEG using subdural grids or depth electrodes, which are constructed based on MEG spike sources, seizure semiology and scalp video EEG. After the identification of the epileptogenic and functional zones, maximum cortical excision and MST are performed to control seizures and to minimize functional deficits. Pediatric neurologists should assess the intractability of epilepsy, identify the epileptogenic zone, determine the excisable epileptic region, and minimize postoperative side effects, thereby leading the epilepsy management team.
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PMID:[Pre- and intra-operative evaluation of epileptic children with intractable seizure disorders: the hospital for sick children]. 1126 Sep 15

Lamotrigine (LTG) as both effective against a wide range of seizure types and epileptic syndromes and well tolerated drug is being used in mono--as well as in polytherapy of pharmacoresistant epilepsy. The aim of this study was to evaluate the efficacy, safety and neuropsychological functioning after LTG (mean daily dose: 316 mg) as long-term monotherapy (12 mo) in 24 young adult out-patients (22.5 ys) with newly recognised and not-previously treated epilepsy in an open, non-comparative trial. 67% of patients were responders (above 50% reduction in seizure frequency) and 42% reported seizures remission. The best were results in patients with generalised convulsive fits (87% with remission). Adverse events in the early phase of medication in 21% of patients typically concerned CNS and gastrointestinal system (headache, asthenia, insomnia, nausea, gastric aches) and resolved spontaneously without treatment discontinuation. Biochemical examinations were normal and transient leucopenia and diminishion of MCV were clinically not significant. Neurodynamic abilities, neuropsychological examination results, memory verbal and visual tests and organic evaluation in organic triada tests did not show deterioration after LTG treatment. Slight difficulties in abstractive and operative thinking and some focal symptoms of fronto-temporal origin should be considered a result of drug but also the epilepsy per se. No significant differences in latencies and amplitudes of evoked potentials (VEP, BAEP, SEP and especially ERP-300) were measured after LTG. Preliminary results obtained in this study supported good efficacy and tolerability and especially lack of unfavourable influence of LTG on neuropsychological functioning in young previously untreated patients with epilepsy.
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PMID:Long-term monotherapy with lamotrigine in newly diagnosed epilepsy in adults. 1197 53

Japanese encephalitis (JE) is an encephalomyelitis involving cortex, subcortex, brainstem and spinal cord. There is paucity of studies on the neurophysiological evaluation in JE. This study aims at comprehensive evaluation of EEG, sensory and motor evoked potentials, nerve conduction and electromyography; and correlate these with clinical findings. Sixty five patients with JE diagnosed on the basis of clinical, radiological and virological criteria were subjected to a detailed clinical evaluation during the acute stage of illness. Cranial CT scan or MRI was carried out in all the patients. All the patients underwent 10 or 18 channel EEG, motor and sensory evoked potentials to both upper and lower limbs bilaterally as well as peroneal and sural nerve conductions and concentric needle EMG. Outcome, was defined at the end of 3 months into poor, partial and complete recovery. The patient's age ranged between 2-65 years. There were 40 males and 25 female patients. Fifteen patients were less than 12 years of age. History of seizure was present in 31 patients. Quadriplegia was seen in 39 and hemiplegia in 8 patients. Muscle wasting was present in 16 patients and tendon reflexes were reduced in 12 and of mixed pattern in 14 patients. Cranial MRI revealed thalamic lesion in 38, basal ganglia in 21, substantia nigra in 30, pons in 5, cerebellum in 3 and cerebral cortex in 7 patients out of 57 patients. EEG revealed nonspecific theta to delta slowing in 45, alpha pattern coma in 5 and epileptiform discharges in 8 patients. EMG revealed fibrillations in 23 patients. Motor evoked potentials were abnormal in 34 out of 46 patients and revealed patchy and focal abnormalities comprising of unrecordable, prolonged and normal pattern. Somatosensory evoked potentials were abnormal in 8 patients only. At 3 month, 26 patients had complete, 13 partial and 15 had poor outcome. Eight patients died in acute stage and 3 were lost to followup. MEP correlated with weakness and 3 month outcome whereas EEG, SEP and EMG did not have any correlation. MEP changes were more frequent in JE and had prognostic significance.
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PMID:Neurophysiological changes in Japanese encephalitis. 1239 49

Centers responding to a survey of MEP monitoring practices predominantly used transcranial electrical brain stimulation (TCES) with brief pulse trains and/or spinal cord stimulation (SCS) to elicit MEPs; transcranial magnetic stimulation and single-pulse TCES were not techniques of choice. Most centers using TCES had patient exclusion criteria (e.g., cochlear implants, cardiac pacemakers, prior craniotomy or skull fracture, history of seizures). Adverse effects included rare tongue injuries or seizures from TCES, and minor bleeding from needle electrodes in muscle. Spinal cord, peripheral nerve, and muscle recording sites were all employed. TCES with recording of muscle responses was the preferred MEP monitoring technique at the plurality of the centers. MEPs suitable for monitoring were obtained in about 91.6% of patients overall. Most of the failures were attributed to technical factors; preexisting neurologic dysfunction precluded MEP monitoring in approximately 1.7% of patients. Almost all centers monitored SEPs concurrently with MEPs. Overall, both measures remained stable during about 90.2% of cases. Adverse MEP changes occurred in about 8.3%; a little over half of these were accompanied by SEP changes. Adverse SEP changes without MEP changes occurred in about 1.5% of cases. SEPs and MEPs should be used together to optimally monitor the spinal cord.
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PMID:Current practice of motor evoked potential monitoring: results of a survey. 1247 90

Tramadol, an analgesic with mean potency one tenth that of morphine is used regularly for the treatment of chronic and postoperative pain. Previous reports have indicated that tramadol may induce seizure activity when given together with a selective serotonin reuptake inhibitor (SSRI). Therefore, its major mode of action may be questioned which purportedly is due to binding with the opioid receptor and partly due to the inhibition of monoamine reuptake. We therefore set out to study its potential in inducing seizure activity and to quantify its effect on EEG-power spectra and on the central modulation of sensory afferents in awake and trained dogs (n=7). In order to demonstrate if opioid receptors mediated these effects, incremental doses of tramadol were given which was followed by naloxone for possible reversal. After a wash-out period the same animals were exposed to graded doses of alfentanil, a pure mu-receptor agonist. Again this was followed by the opioid antagonist naloxone for reversal.The electroencephalogram (EEG) and the event-related evoked potentials (SEP) were used to demonstrate possible excitatory effects. In order to derive the SEP the front paw was stimulated electrically (Digi Stim II trade mark ) while the evoked potentials were picked up contralaterally from the somatosensory cortex using stick-on electrodes. 256 sweeps were averaged (Lifescan) and the peak-to-peak amplitude was measured to demonstrate CNS excitation compared to control (%). Additionally, the raw electroencephalogram was viewed for epileptogenic changes and its power computed into the various power bands alpha, beta, delta und theta using FFT over a time epoch of 60 s. Following control, graded doses of either tramadol (2-5-10 mg/kg i.v.) or alfentanil (10-30-60 microg/kg i.v.) were given every 15 min while the EEG and the SEP were recorded. Thereafter naloxone (20 microg/kg i.v.) was injected for reversal. Tramadol did not suppress the amplitude of the SEP at any dose. High doses (>5 mg/kg i.v.) resulted in an increase (+100%) of the amplitude of the evoked potential. This was accompanied by short-term muscle fibrillations, and a short-term spike-and-wave activity in the EEG followed by a long-lasting theta-dominance. These effects could not be reversed by naloxone. In contrast to tramadol, alfentanil induced a dose-related depression of amplitude in the SEP with a maximum of 82% suggesting a depressive effect of modulation of afferents in the sensory cortex. This effect was fully naloxone reversible and was followed by a rebound in amplitude of the SEP together with an increase in fast beta-waves in the EEG. Tramadol very little mediates its central action via the mu-opioid receptor as the present effects were not naloxone reversible. Consistent with the results is the very low affinity of tramadol to the opioid receptor which is several thousand times less than that of morphine. Most likely, inhibition of central norepinephrine and serotonin reuptake as well as the reduction in 5-HT-turnover may contribute to the effects of tramadol. Due to the monoamine reuptake inhibition an increase in transmission may result, triggering off excitatory phenomena with spike-and-wave activity in the CNS. Such excitatory effects, however, may only be seen when tramadol is used in doses exceeding the therapeutic range.
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PMID:[The opioid tramadol demonstrates excitatory properties of non-opioid character--a preclinical study using alfentanil as a comparison]. 1279 88


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