Suppression Of Epileptic Discharges Research Articles

Our experience of pediatric epilepsy surgery

Objective: to evaluate the effectiveness and safety of different operations in children with drug-resistant epilepsy. Materials and Method. 91 children with drug-resistant epilepsy were enrolled in a retrospective study. Mean age was 10.3±5.1 years. Anterior temporal lobectomy was performed in 16 (57.1%) patients, lesionectomy – in 9 (10.0%), microsurgical callosotomy in 18 (19.8%), stereotactic callosotomy in 7 (7.7%), multifocal resections in 4 (4.4%), functional hemispherotomy in 14 (15.6%). Stereotactic radiofrequency callosotomy was performed on a CRW Stereotactic frame (Radionics Inc., USA). Ultrasound navigation and neuronavigation were used in 6 (7%) and 14 (15%) cases correspondingly. Intraoperative corticography was applied in 8 (9%) cases. Postoperative long-term follow-up lasted from 1 to 17 years (mean - 8.2±2.1 years). Results. An epileptogenic zone within single hemisphere was indentified in 66 (72.2%) cases, while bilateral epileptiform activity was observed in 25 (27.5%) children. The most common etiologies of epilepsy included hypoxic-ischemic encephalopathy, intracerebral hemorrhage, meningoencephalitis, Rasmussen syndrome, cortical dysplasia, tumors.After surgery 51 (56%) patients became seizures free (Engel 1), 14 (15.4%) patients had rare auras or focal seizures (Engel 2). In 25 (27.5%) cases, seizure frequency reduction was less than 75% or did not change significantly. The most favorable outcomes were associated with resection procedures, resulting in complete seizure control in 46 (69.7%) out of 66 children, with significant improvement observed in 9 (13.6%) cases. After callosotomy drop-attacks stopped in 14 (78%) out of 18 who had them before surgery. Operative complications were encountered in 6 (6.6%) cases, postoperative mortality occurred in 1 (1.1%) case. Conclusions. The key to the effectiveness of surgical treatment of childhood epilepsy is early surgical intervention, which leads to the control of epileptic seizures, correction of psychological and cognitive emotional disorders and improvement of quality of life. The combination of resection procedures and disconnections contributes to the reduction of epileptogenic neurons and suppression of epileptic discharges.

The clinical significance and electrophysiologic findings of fixation-off and closure of the eyes sensitivity: Data from a prospective unselected population

PurposeElectroencephalography (EEG) findings related to the eye-closing motion can be defined in two ways: ‘sensitivity to eyes closed’ (SEC) and ‘eye closure sensitivity (ECS).’ Fixation-off sensitivity (FOS) is a different phenomenon induced by the elimination of central vision/fixation. The purpose of our study was to determine the frequencies of SEC, ESC, and FOS, and to analyze the relationship between eyes closure and the fixation-off phenomenon and clinical importance in an unselected population. MethodsWe prospectively evaluated 200 routine interictal EEGs by adding a standardized FOS examination protocol between June and September 2015. Goggles covered with semitransparent tape were used to evaluate FOS. We determined SEC when the epileptiform discharges appeared during eye closure and continued during the eye closed state, whereas ECS was defined as transient epileptic abnormalities following the closure of the eyes lasting for 1−4 sec. The patients were evaluated in terms of demographic characteristics, clinical features, and the relationship between SEC, ECS, and FOS. ResultsWe detected SEC in 9 (4.4 %) and ECS in 11 (5.4 %) patients. FOS was detected in four (44.4 %) of the patients who showed SEC, all of whom had occipital epileptiform discharges. A statistically significant correlation was found between FOS and treatment resistance in the SEC group (p < 0.001). In logistic regression analysis, occipital lobe epilepsy (p < 0.001) and age under 20 years (p = 0.004) were found as risk factors for SEC. Another interesting finding was the suppression of epileptic discharges with fixation-off in three of 11 patients with ECS. ConclusionsAccording to the results of our study, FOS is related to treatment resistance. Therefore, FOS should be evaluated in patients with SEC.

CONNECTION BETWEEN EPILEPSY AND AUTISM SPECTRUM DISORDER

The role of epilepsy in developing autism spectrum disorders (ASD) is not well understood. According to some reports, epilepsy of early childhood is often found in patients with autism of early childhood. In such children, epilepsy can progress at later periods, while the presence of both disorders in one child has a specific clinical pattern and requires specific treatment. The question whether suppression of epileptic discharges on the EEG could lead to cognitive improvement in children with ASD remains open. Likewise, the etiology of autism and its possible links to epilepsy and other pediatric disorders need more research. Here we present an overview of recent clinical studies on the proposed connection between epilepsy and ASD.

てんかん波抑制における冷却速度と脳波帯域の関係

Focal brain cooling can suppress epileptic discharges (EDs) in the cerebral cortex and also suppress frequency spectral powers in the EDs with temperature-dependent effect. The objective of this paper is to investigate the dependence of the cooling rate on the EDs suppression with experiments using 4 epilepsy model rats. The cortical surface of the rats was cooled to 16oC, and time condition for brain cooling from initial temperature to 16oC was set at 30, 60, 100 and 200 sec respectively. Obtained ECoG data were divided for 4 frequency bands (δ(0.5-4Hz), θ(4-8Hz), α(8-13Hz), β(13-30Hz)) to elucidate the effect of change in the frequency band of EDs depending on the cooling rate. The power spectral during cooling of each condition were compared to the power spectral of pure EDs (non-cooling state). Our results demonstrated that the suppression of EDs have a cooling rate dependency, and all of the frequency band in the EDs are smaller when the cooling rate is slower. These findings could contribute to elucidation of the mechanism of suppression EDs.

Drug refractory epilepsy in brain damage: effect of dextromethorphan on EEG in four patients.

High doses of dextromethorphan (20-42 mg/kg/day) were given to four critically ill children with seizures and frequent epileptiform abnormalities in the EEG that were refractory to antiepileptic drugs. Their acute diseases (hypoxia, head trauma and hypoxia, neurodegenerative disease, hypoglycaemia) were thought to be due in part to N-methyl-D-aspartate (NMDA) receptor mediated processes. Treatment with dextromethorphan, an NMDA receptor antagonist, was started between 48 hours and 14 days after the critical incident. In three patients the EEG improved considerably within 48 hours and seizures ceased within 72 hours. In the patient with neurodegenerative disease the effect on the EEG was impressive, but the seizures were not controlled. Despite the improvement of the EEG the clinical outcome was poor in all children: three died in the critical period or due to the progressing disease; the patient with hypoglycaemia survived with severe neurological sequelae. Plasma concentrations of dextromethorphan varied between 74-1730 ng/ml and its metabolite dextrorphan varied between 349-3790 ng/ml. In one patient corresponding concentrations in CSF were lower than those in plasma. The suppression of epileptic discharges by the doses of dextromethorphan given suggests that such doses are sufficient to block NMDA receptors.

Treatment and Discontinuation of Antiepileptic Drugs in Childhood Epilepsy

: The process of discontinuing anticonvulsant therapy was studied clinicoelectroencephalographically on 285 children with epilepsy. The subjects were divided into two groups electroencephalographically: First, 190 cases of the formally discontinued group which had antiepiletic drugs withdrawn after the cessation of clinical seizures and suppressing epileptic discharges for over two years and, second, 95 cases which were informally discontinued. The relapse rate after discontinuation was significantly lower in the former group, 2.1%, than the latter group, 21.1%. Concerning the seizure-free period, among the cases free from clinical seizures for over three years at the time of withdrawal, the relapse rate was significantly lower than the rest of the cases. Moreover, the spike-free period proved to be a more reliable indicator for stopping medication than the seizure-free period. From these findings, the withdrawal of antiepileptic drugs should be started after suppression of epileptic discharges for over two years in childhood epilepsy.