Epileptiform Activity In Patients Research Articles

Temporal Lobe Epilepsy with Bitemporal Interictal Epileptiform Discharges: Effects of Sleep and Wakefulness

Introduction. Independent bitemporal interictal discharges are often found in patients with temporal lobe epilepsy. The likelihood of registering epileptiform activity (EA) is higher during sleep. Assessment of bitemporal interictal epileptiform discharges (BIEDs) with various discharge predominance ratio is used for presurgical evaluation of epilepsy patients and prediction of surgical outcomes. Our objective was to determine the predominant side (PS) in patients with bitemporal epilepsy using the incidence of epileptiform discharges for each sleep stage. Materials and methods. We analyzed 45 recordings of 10–24 h long-term video-EEG monitoring (LTM) in patients with bitemporal EA. For each recording, the total incidence of EA (IEA) and EA incidence for wakefulness and for each sleep stage were calculated individually. We also assessed the discharge predominance index (DPI) as a ratio of IEA in the predominant and contralateral sides for the entire recording and for each sleep stage. Results. We observed an IEA increase with sleep deepening, with maximum values observed during N2 and N3 sleep stages. The minimum IEA values were recorded during REM sleep; nevertheless, most of the REM sleep discharges were detected on the PS. DPI values were the highest and the most stable during N2 and N3 stages. Conclusion. The findings of our study demonstrate an increase in DPI values with non-rapid eye movement (NREM) sleep deepening in patients with bitemporal localization of EA. Despite the protective effects of REM sleep (i.e., reducing the likelihood of EA), it may be pivotal in lateralization of EA in patients with BIEDs. The PS is generally determined by a higher DPI during N2 and N3 stages.

Features of epileptiform activity in patients with diagnosed glioblastoma: from genetic and biochemical mechanisms to clinical aspects

Introduction. glioblastomas multiforme (grade Iv gliomas) are common and the most aggressive primary tumors of the brain with very unfavorable prognosis. In all previously published papers on epileptiform activity in glioblastomas, not enough information on encephalogram results is presented.Aim. To study the features of epileptiform activity in patients with glioblastomas and development of a plan for further study of these patients.Materials and methods. An analysis of articles from Elsevier, Embase, Scopus, The Cochrane Library, global Health, Russian Science Citation Index (RSCI) databases, Scholar, google, web of Science, pubmed search engines and scientific electronic library CyberLeninka was performed. materials were selected considering journal indexing system and citations, scientific novelty of the studies, statistical significance of the results. publications repeating data from previous articles or describing animal experiments were excluded from analysis.Results. During the study, data on mechanisms of epileptiform activity pathogenesis, predisposing factors (tumor location in the temporal, frontal or parietal lobes, IDH-1 and / or IDH-2 gene mutations), treatment options in patients with glioblastomas were systemized. Additionally, and original plan of data accumulation for clinical studied taking into account limitations of the previous studies was developed to increase quality of results interpretation.Conclusion. Epileptiform symptoms in glioblastomas negatively affect patients’ quality of life and lifespan. Currently, researchers actively search for an effective method of treatment of epileptic seizures in patients with glioblastomas. The most effective is combination of temozolomide with valproate and levetiracetam due to good control of seizure frequency, low toxicity, and pharmacological synergy between the drugs.

Machine learning‐enabled epileptiform spike detection stratifies patient subpopulations with Alzheimer’s disease

AbstractBackgroundA subpopulation of patients with Alzheimer’s disease exhibit epileptiform activity and have more rapidly progressing disease. Manual identification of these pathological events is infeasible at scale and machine learning tools may establish epileptiform activity as an actionable biomarker for stratification and endpoints within clinical trials.MethodsRoutine EEGs from 90 subjects with AD and 39 subjects with MCI from the Beacon data repository were analyzed via the Beacon Platform harnessing an ML‐enabled interictal epileptiform discharge (IED) detection algorithm, and by expert visual inspection.ResultsIEDs were found in 17 of the 90 subjects with AD (19%), and 8 out of the 39 MCI subjects (20%). In subcategorization, 13% (9 / 71) of AD subjects without epilepsy had IEDs, while 42% (8/19) of AD subjects with epilepsy had IEDs. In the AD/no epilepsy subgroup there were 24 patients taking an Anti‐Seizure Medication (ASM), and 4% (1/24) had IEDs (versus 17% (8/47) of the AD without epilepsy group that were not on ASMs).ConclusionMachine learning augmented detection of IEDs allows for rapid, quantitative identification of individuals with subclinical epileptiform activity in patients with AD and MCI. These results demonstrate that AI‐detectable IEDs are seen in a sizable minority of AD patients without epilepsy and in MCI patients, and more commonly in AD patients with epilepsy. Ultimately, automated analysis of EEG data is a promising way to stratify patients and track disease progression while enriching clinical trials with subjects most likely to respond to next‐generation treatments.

Acute Effects of High-Frequency Insular Stimulation on Interictal Epileptiform Discharge Rates in Patients with Refractory Epilepsy.

Rationale: Deep brain stimulation (DBS) of several sites, such as the thalamus, has been shown to reduce seizure frequency and interictal epileptiform activity in patients with refractory epilepsy. Recent findings have demonstrated that the insula is part of the 'rich club' of highly connected brain regions. This pilot study investigated short-term effects of high-frequency (HF) insular DBS on interictal epileptiform discharge (IED) rate in patients with refractory epilepsy. Methods: Six patients with drug-resistant epilepsy undergoing an intracranial electroencephalographic study received two sets of 10 min continuous 150 Hz HF-DBS of the insula. For each patient, epileptiform activity was analyzed for a total of 80 min, starting 20 min prior to stimulation set 1 (S1), and ending 20 min after stimulation set 2 (S2). All IEDs were identified and classified according to their anatomic localization by a board-certified epileptologist. The IED rate during the 20 min preceding S1 served as a baseline for comparison with IED rate during S1, S2 and post-stimulation periods. Results: HF-DBS of the anterior insula (aINS) was performed in a patient with an aINS epileptic focus (patient 1). HF-DBS of the posterior insula (pINS) was performed in two patients with a pINS epileptic focus (patients 2 and 4), in one patient with an aINS focus (patient 3), and in two non-insular patients (patients 5 and 6). The total IED (irrespective of their location) rate significantly decreased (p < 0.01) in two patients (patients 1 and 2) during the stimulation period, whereas it significantly increased (p < 0.01) in one patient (patient 6); there was no change in the other three patients. Looking at subsets of spike localization, HF-DBS of the aINS significantly reduced aINS and orbitofrontal IEDs in patient 1 (p < 0.01), while HF-DBS of the pINS had an effect on pINS IEDs (p < 0.01) in both patients with a pINS focus; there was no significant effect of HF-DBS of the insula on IEDs in temporal or other frontal regions. Conclusion: Short-term HF-DBS of the insula had heterogeneous effects on the IED rate. Further work is required to examine factors underlying these heterogeneous effects, such as stimulation frequency, location of IEDs and subregions of the insula stimulated.

Abnormalities of Cortical Sources of Resting State Delta Electroencephalographic Rhythms Are Related to Epileptiform Activity in Patients With Amnesic Mild Cognitive Impairment Not Due to Alzheimer's Disease.

In the present exploratory and retrospective study, we hypothesized that cortical sources of resting state eyes-closed electroencephalographic (rsEEG) rhythms might be more abnormal in patients with epileptiform EEG activity (spike-sharp wave discharges, giant spikes) and amnesic mild cognitive impairment not due to Alzheimer's disease (noADMCI-EEA) than matched noADMCI patients without EEA (noADMCI-noEEA). Clinical, neuroimaging, neuropsychological, and rsEEG data in 32 noADMCI and 30 normal elderly (Nold) subjects were available in a national archive. Age, gender, and education were carefully matched among them. No subject had received a clinical diagnosis of epilepsy. Individual alpha frequency peak (IAF) was used to determine the delta, theta, and alpha frequency bands of rsEEG rhythms. Fixed beta and gamma bands were also considered. Regional rsEEG cortical sources were estimated by eLORETA freeware. Area under receiver operating characteristic (AUROC) curves indexed the accuracy of eLORETA solutions in the classification between noADMCI-EEA and noADMCI-noEEA individuals. As novel findings, EEA was observed in 41% of noADMCI patients. Furthermore, these noADMCI-EEA patients showed higher temporal delta source activities as compared to noADMCI-no EEA patients and Nold subjects. Those activities discriminated individuals of the two NoADMCI groups with an accuracy of about 70%. The significant percentage of noADMCI-EEA patients showing EEA and marked abnormalities in temporal rsEEG rhythms at delta frequencies suggest a substantial role of underlying neural hypersynchronization mechanisms in their brain dysfunctions.

Epilepsy and interictal epileptiform activity in patients with autism spectrum disorders

PurposeThe purpose of this study was to determine the prevalence of epilepsy and subclinical epileptiform abnormalities in children with autism spectrum disorder (ASD), and to investigate its effects on core autistic symptoms and adaptive behavior skills. MethodsPatients with diagnosis of ASD who met full criteria on Autism Diagnostic Interview-Revised (ADI-R) were included in the study. Adaptive behavior skills were assessed by Vineland Adaptive Behavior Scale-II (VABS-II). Clinical assessment for epilepsy and video electroencephalography (EEG) (v-EEG) examinations during wakefulness and/or sleep were prospectively performed in all patients. ResultsA total of 112 patients with diagnosis of ASD of mean age 6.58 ± 3.72 were included in the study. Based on clinical and v-EEG assessments, three groups of patients were defined: 1) patients with epilepsy (n = 17; 15.2%); 2) patients with epileptiform discharges in absence of clinical seizures (n = 14; 12.5%); 3) patients without epilepsy and without epileptiform discharges (n = 81; 72.3%). There were no significant differences between three groups of patients on ADI-R subscores. Speech development was also not significantly related to epilepsy. There was a slight tendency of the VABS-II motor skills score to be higher in the group of patients with autism without clinical diagnosis of epilepsy and without subclinical epileptiform discharges (p < 0.05) in comparison with the two other groups. According to this tendency, we might claim that patients with higher scores on motor skills could have 0.88 times lower odds for having epileptiform EEG activity. ConclusionsAccording to our results, we were not able to detect differences in the ADI-R between the three populations with ASD, all with unknown etiology. Epilepsy, as well as subclinical epileptic discharges, showed small effects on Motor Skills in patients with autism, and had no effect on adaptive behavior Communication/Socialization/Daily Living Skills.

S123. Paroxysmal Focal Epileptiform Discharges (PFEDs) on intraoperative high density electrocorticography

Lateralized Periodic Discharges (LPDs) have been described in adults primarily with acute structural lesions involving gray and white matter. High-density scalp EEG improves the capture of neural signals compared to standard recording. “Microseizures” and “microdischarges” have been identified in small volumes of cortex using hybrid intracranial electrodes for research. However little data exists regarding the utility of HD-ECoG in identifying epileptiform discharges during intraoperative monitoring. ECoG was performed prospectively as part of a protocol evaluating functional brain mapping in consecutive patients utilizing direct electrocortical stimulation (DECS). High-density ECoG (HD-ECoG) recordings were conducted with subdural grids (64 contact in 57.9%; 32 contacts in 8.6%; 22 in 13.8%; <22 in 20.7%) and intermittent use of surgeon-guided depth ECoG. The presence, location, and frequency of epileptiform discharges was judged by two of the co-authors (WOT and AMF) independently for inter-rater reliability of discharges when they appeared periodic. Fifty-eight operated patient s (33 females) with a median age of 51 years (range: 18–79) underwent awake craniotomy for resection of a structural lesion. 40/58 patients (69.0%) had seizures as their presenting clinical feature, 21/58 (36.2%) had both a brain tumor with seizures. Levitiracetam was the most common ASD used. MRI identified a lesion in 56/58 cases (82% tumoral vs 18% non-tumoral etiology). Lesions were most common in the frontal lobes of the brain in 26 (44.8%) patients and temporal lobe in 25 (43.1%) cases. Glioblastoma was the most common pathology encountered in 29.31%. 15/58 (25.9%) patients underwent standard EEG prior to intraoperative ECoG. 7 (47.6%) patients had a normal or non-specific EEG. Of these 4/7 (57.1%) had epileptiform discharges (EDs) on HD-ECoG. 33/58 (56.9%) of patients had HD-ECoG and 19/33 (57.6%) of patients demonstrated EDs on intraoperative HD-ECoG. PFEDs occurred in 9 (15.5%) of cases and identified by HD-ECoG in 1 on depth ECoG. 8/9 PFEDs recurred at <1 Hz and appeared in less than 6 electrodes (3 cm) on HD-ECoG grid (median: 4) and only one had EDs on scalp EEG appearing in a different area from PFEDs. Thirty-eight (97%) of patients with seizures who underwent DCES during awake craniotomy improved (Engel Class I 68.4%, II 18.4%, and III 13.2%) with a mean follow-up >6 months. Intraoperative awake HD-EcOG has a high yield in identifying abnormal epileptiform activity in patients undergoing lesional respective surgery. The increased spatiotemporal resolution offered by HD-ECoG is sensitive for the detection of subclinical epileptiform activity not identifiable by standard EEG methods. Periodic focal epileptiform discharges are a unique feature of intraoperative HD-ECoG and may provide localizing information to guide resection in patients undergoing surgery for a lesion with seizures.

The Significance of Sleep Deprivation in the Development of Local Epilepsy from the Point of View of Neuroplasticity

Objective. To study the neurological and electrophysiological manifestations of sleep deprivation (SD) in patients with local symptomatic forms of epilepsy and in healthy subjects and to investigate the neuromorphological patterns of SD in experimental conditions. Materials and methods. Complex clinical and electroencephalographic (video-EEG monitoring with sleep traces) studies were performed before and after SD for 48 h in 178 patients with locally originating epilepsy (LOE) and 45 healthy control subjects. Neurohistological and electron microscopic investigations of the brain were performed in rats after 48-h SD. Results and discussion. SD led to increases in epileptiform activity in patients with LOE (with increases in the frequency of epileptic seizures) and the onset of this activity in healthy subjects. Post-SD morphological changes in rat brains consisted of mitochondrial pleioconia, damage to elements of the blood-brain barrier, signs of astrocyte depletion, changes in gliocyte nuclei of the apoptotic and karyorrhectic types, and destruction of synapses; these were evidence of impairment to the mechanisms of neuroplasticity after SD. These results allow SD in patients to be regarded as a factor damaging the CNS and provoking the development of epileptic seizures in epilepsy. SD in experimental animals can be used as a model for further studies of the mechanisms of neuroplasticity.

Application of MEG coherence in lateralization of mTLE.

Magnetoencephalography (MEG) is a noninvasive imaging method for localization of focal epileptiform activity in patients with epilepsy. This study investigates the cerebral functional abnormalities quantified by MEG coherence laterality in mesial temporal lobe epilepsy (mTLE). Resting state MEG data was analyzed using MEG coherence source imaging (MEG-CSI) method to determine the coherence in 54 anatomical sites in 12 adult mTLE patients and 12 age- and gender-matched controls. MEG coherence laterality, after Bonferroni adjustment, showed significant differences for right versus left mTLE in insular cortex and both lateral orbitofrontal and superior temporal gyri (p<;0.025). None of these anatomical sites showed statistically significant differences in coherence laterality between right and left sides of controls. Coherence laterality was in agreement with the declared side of epileptogenicity in insular cortex (in 75% of patients) and both lateral orbitofrontal (83%) and superior temporal gyri (84%). Combining all significant laterality indices improved the lateralization accuracy to 92%. The proposed methodology for using MEG to investigate the abnormalities related to focal epileptogenicity and propagation can provide a further means of noninvasive lateralization.

P.069 The predictive factors of electroencephalograms with epileptiform activity in psychiatric patients

Background: Psychiatrists commonly use electroencephalogram (EEG) to rule out epilepsy as a cause of psychiatric symptoms. A large number of these studies are normal. Our study aims to identify the predictive factors of an EEG with epileptiform activity in these patients. Methods: We performed a retrospective study of the EEG results and chart reviews of the 208 psychiatric patients at Royal University Hospital in Saskatoon, Saskatchewan from 2013-2015. The EEG results were correlated with several factors known to increase the probability of an abnormal recording including history of seizures, previously abnormal EEGs, imaging abnormalities, medications known to cause epileptiform discharges, electroconvulsive therapy, prematurity, brain infection, childhood febrile seizures, head trauma, and family history. Results: Of the 208 EEGs performed, 176 (84%) were normal (77%) or essentially normal (7%). Epileptiform activity was found in 13 EEGs (6.3%), of which 9 (4.3%) had a previous EEG with epileptiform activity. Focal slowing appeared in 12 EEGs (5.8%), two of which had previous abnormal EEGs. Generalized slowing was found in 7 EEGs (3.4%). Conclusions: We conclude that the majority of EEGs in patients with psychiatric manifestations are normal. The most predictive factor for epileptiform activity in this population is a previous EEG with epileptiform discharges. Other predictive factors are under review.

MEG Coherence and DTI Connectivity in mTLE.

Magnetoencephalography (MEG) is a noninvasive imaging method for localization of focal epileptiform activity in patients with epilepsy. Diffusion tensor imaging (DTI) is a noninvasive imaging method for measuring the diffusion properties of the underlying white matter tracts through which epileptiform activity is propagated. This study investigates the relationship between the cerebral functional abnormalities quantified by MEG coherence and structural abnormalities quantified by DTI in mesial temporal lobe epilepsy (mTLE). Resting state MEG data was analyzed using MEG coherence source imaging (MEG-CSI) method to determine the coherence in 54 anatomical sites in 17 adult mTLE patients with surgical resection and Engel class I outcome, and 17 age- and gender- matched controls. DTI tractography identified the fiber tracts passing through these same anatomical sites of the same subjects. Then, DTI nodal degree and laterality index were calculated and compared with the corresponding MEG coherence and laterality index. MEG coherence laterality, after Bonferroni adjustment, showed significant differences for right versus left mTLE in insular cortex and both lateral orbitofrontal and superior temporal gyri (p<0.017). Likewise, DTI nodal degree laterality, after Bonferroni adjustment, showed significant differences for right versus left mTLE in gyrus rectus, insular cortex, precuneus and superior temporal gyrus (p<0.017). In insular cortex, MEG coherence laterality correlated with DTI nodal degree laterality ([Formula: see text] in the cases of mTLE. None of these anatomical sites showed statistically significant differences in coherence laterality between right and left sides of the controls. Coherence laterality was in agreement with the declared side of epileptogenicity in insular cortex (in 82% of patients) and both lateral orbitofrontal (88%) and superior temporal gyri (88%). Nodal degree laterality was also in agreement with the declared side of epileptogenicity in gyrus rectus (in 88% of patients), insular cortex (71%), precuneus (82%) and superior temporal gyrus (94%). Combining all significant laterality indices improved the lateralization accuracy to 94% and 100% for the coherence and nodal degree laterality indices, respectively. The associated variations in diffusion properties of fiber tracts quantified by DTI and coherence measures quantified by MEG with respect to epileptogenicity possibly reflect the chronic microstructural cerebral changes associated with functional interictal activity. The proposed methodology for using MEG and DTI to investigate diffusion abnormalities related to focal epileptogenicity and propagation may provide a further means of noninvasive lateralization.

CLINICAL SIGNIFICANCE OF EPILEPTIFORM ACTIVITY IN ELECTROENCEPHALOGRAM

The article is devoted to some issues of sensitivity and specificity of epileptiform activity in the electroencephalogram (EEG). Epileptiform activity – it is sharp waves and spikes on EEG. Normal EEG does not exclude the diagnosis of epilepsy and viсe versa: presence of epileptiform activity on EEG is not necessarily caused by epilepsy. Several EEGs may be needed to detect epileptiform activity in patients with epilepsy. EEG recording during sleep with the use of different activation methods (hyperventilation, rhythmic photic stimulation, sleep deprivation) can increase the probability of epileptiform activity detection. Clinical presentation should be taken into account while interpreting EEG results with registered epileptiform activity. The issues of epileptiform activity classification and differential interpretation of other electrical activity types are also discussed in the article. Main epileptiform patterns, their neurophysiological basis and correlation with clinical manifestations are described.

P472: Epileptiform activity in patients treated with therapeutic hypothermia after cardiac arrest

P472: Epileptiform activity in patients treated with therapeutic hypothermia after cardiac arrest

LP31: EEG and MEG source localization of the epileptogenic foci in tuberous sclerosis complex: a pediatric case report

LP31: EEG and MEG source localization of the epileptogenic foci in tuberous sclerosis complex: a pediatric case report

Study on concordance of ictal and interictal epileptiform activity in patients with tuberous sclerosis complex

To analyze the relationship between the ictal onset zone and dominant interictal epileptiform foci in tuberous sclerosis complex (TSC) patients. Clinical data of 20 patients with TSC which had epileptic seizures during Video-EEG monitoring was assessed. Consistency and dominance of focal interictal epileptiform activity and the ictal onset zone were identified. Concordance between interictal and ictal findings was analyzed. Of the 20 patients, 7 were female, and 13 were male. The age of epilepsy onset was from 15 d to 6 years. The Video-EEG monitoring age was from 6 months to 11 years. Family history was found in three cases. Abnormality in neuroimaging existed in 17 of 18 patients who were examined. Interictal EEG showed hypsarrhythmia in 3 patients, multifocal epileptiform activity with a dominant focus in 12 patients, both focal and generalized discharges in 2 patients, and only focal discharges in 3 patients. The seizures types during EEG monitoring included epileptic spasms, partial seizure, atypical absence, and generalized or focal myoclonic seizure. The most common seizure type was partial seizure and then epileptic spasms. EEG in 4 patients with epileptic spasms showed ictal generalized discharges and interictal hypsarrhythmia or generalized discharges. Clinical manifestation of epileptic spasms was asymmetric in 3 patients. Lateralization and location of interictal and ictal discharges were consistent in 2 of the 3 patients, while only lateralization consistency in 1 of the 3 patients. Partial seizures as the only seizure type were monitored in 13 patients. Of the 13 patients, lateralization and location of interictal and ictal discharges were inconsistent in 2 patients (15%), consistent in 8 patients (62%), lateralization or location consistent in 2 patients (15%). One case could not be analyzed because of uncertainty of lateralization and location of seizure onset. In the majority of patients with TSC, multifocal interictal epileptiform activity is present, in which a most dominance of focal epileptiform activity could be found. For some epileptic seizures or the majority of partial seizures, the ictal onset zone is concordant with the dominance of focal interictal epileptiform foci. The concordance might have positioning reference significance for preoperative evaluation of epilepsy surgery.

Does the Reduction of Epileptiform Activity in Patients with Electrical Status Epilepticus in Sleep Treated with High-Dose Diazepam Persist over Time? (P03.015)

Does the Reduction of Epileptiform Activity in Patients with Electrical Status Epilepticus in Sleep Treated with High-Dose Diazepam Persist over Time? (P03.015)

Identifying the cortical substrates of interictal epileptiform activity in patients with extratemporal epilepsy: An EEG‐fMRI sequential analysis and FDG‐PET study

The aim of this study was to apply sequential analysis of electroencephalography-functional magnetic resonance imaging (EEG-fMRI) data to study the cortical substrates related to the generation of the interictal epileptiform activity (IEA) in patients with pharmacoresistant extratemporal epilepsy. We analyzed fMRI data from 21 children, adolescents, and young adults patients who showed frequent bursts or runs of spikes on EEG, by using the sequential analysis method. We contrasted consecutive fixed-width blocks of 10s to obtain the relative variations in cerebral activity along the entire fMRI runs. Significant responses (p<0.05, family-wise error (FWE) corrected), time-related to the IEA recorded on scalp EEG, were considered potential IEA cortical sources. These results were compared with those from the fluorodeoxyglucose-positron emission tomography (FDG-PET), intracranial EEG (two patients), and surgery outcome (eight patients). The typical IEA was recorded in all patients. After the sequential analysis, at least one significant blood oxygen level-dependent (BOLD) response spatially consistent with the presumed epileptogenic zone was found. These IEA-related activation areas coincided when superimposed with the hypometabolism depicted by the FDG-PET. These data were also consistent with the invasive EEG findings. Epileptic seizures were recorded in eight patients. A subset of IEA-associated fMRI activations was consistent the activations at seizure-onset determined by sequential analysis. The inclusion of the IEA-related areas in the resection rendered the patients seizure-free (five of eight operated patients). The EEG-fMRI data sequential analysis could noninvasively identify cortical areas involved in the IEA generation. The spatial relationship of these areas with the cortical metabolic abnormalities depicted by the FDG-PET and their intrinsic relationship regarding the ictal-onset zone could be useful in epilepsy surgery planning.

Short-Term Response of Sleep-Potentiated Spiking to High-Dose Diazepam in Electric Status Epilepticus During Sleep

We describe the short-term effects of high-dose oral diazepam on sleep-potentiated epileptiform activity in patients with electric status epilepticus during sleep. We enrolled patients treated with high-dose oral bedtime diazepam from 2001-2009. We defined spike percentage as the percentage of 1-second bins containing at least one spike, and calculated it during three randomly selected 5-minute samples of wakefulness throughout the day and during the first 5 minutes of every hour of non-rapid eye movement sleep at night. In this study, patients were considered to demonstrate sleep-potentiated epileptiform activity when their spike percentage during sleep was increased by ≥50% compared with wakefulness. Twenty-nine children (18 boys) were included (median age, 7.4 years). Twenty-four hours after receiving high-dose diazepam, epileptiform activity was significantly reduced (76.7% at baseline vs 40.8% 24 hours after high-dose diazepam; Wilcoxon signed ranks test, Z=-4.287, P < 0.0001). Seven patients (24.1%) manifested mild, reversible side effects during the first 48 hours after diazepam administration. High-dose oral diazepam effectively and safely reduced epileptiform activity in patients with electric status epilepticus during sleep.

Effects of antiepileptic drugs on electroencephalographic findings in patients with idiopathic generalized epilepsy.

How to Cite this Article: Asadi-Pooya AA, Emami M. Effects of Antiepileptic Drugs on Electroencephalographic Findings inPatients with Idiopathic Generalized Epilepsy. Iranian Journal of Child Neurology 2011;5(4):33-36. Objective Several antiepileptic drugs (AEDs) such as phenobarbital (Pb), carbamazepine (CBZ), and valproate (VPA) may suppress interictal epileptiform activity. We investigated the effects of AEDs on electroencephalography (EEG) data from patients with idiopathic generalized epilepsy (IGE). Materials & Methods In this cross-sectional study, all patients electroclinically diagnosed with IGE were recruited in the outpatient epilepsy clinic at Shiraz University of Medical Sciences from September 2008 through August 2010. A routine EEG was requested at the time of referral for all patients. Statistical analyses were performed using Chi square and Fisher’s exact test. Results This study comprised of 336 patients. For about 20.8% (70 patients) of them, the initial EEG appeared normal. The first EEG was normal in 14.2% of the patients who had newly diagnosed IGE (19 patients). Normal EEG was also detected for 27.6% of the patients who received VPA monotherapy (16 patients), 31% of the patients who received CBZ monotherapy (9 patients), 29.4% of the patients who received Pb monotherapy (5 patients), and 11.1% of the patients who received lamotrigine (LTG) (1 patient). Conclusion This study shows that compared to LTG, VPA suppresses generalized interictal epileptiform activity in patients with IGE more effectively. Theoretically, if a drug can frequently induce normalization of EEG, then it may be a better drug for treating IGEs.

Subcontinuous epileptiform activity after failed hippocampal radiosurgery

Although gamma-knife radiosurgery (GKS) has proved efficacious in temporal lobe epilepsy (TLE), its antiepileptic mechanism of action remains elusive. Human and experimental data suggest that subnecrotic radiation-induced tissue changes might contribute to the antiepileptic effect of GKS. However, there are no data regarding the evolution of electroencephalography (EEG) activity within GKS-treated hippocampus, information that aid in better understanding both the mechanism of action and the reason for failure of GKS treatment. Two patients with disabling seizures 4 and 6 years after mesial temporal GKS with a marginal dose of 24 Gy were investigated with stereotactic intracerebral EEG recordings. Both patients had right TLE with hippocampal atrophy, but with past history of Coxsackie virus meningoencephalitis and congenital toxoplasmosis, respectively. Ten to 12 electrodes were implanted, including seven to eight electrodes within the epileptic temporal lobe. In both patients, depths electrodes placed within the irradiated mesial temporal structures disclosed a remarkable pattern of subcontinuous spiking activity intermingled with asymptomatic rhythmic discharges up to 1 min in duration. This activity differed from the abnormalities usually captured in mesial TLE (mTLE) and suggested radiosurgery-induced brain changes. Both patients underwent anterior temporal lobectomy and achieved a class I outcome after a follow-up of 18 and 40 months, respectively. Pathologic examination of the surgical specimens showed variable degrees of radiation-effect changes. Our study shows that mesial temporal structures previously treated with GKS can demonstrate a persistent high degree of epileptiform activity in patients who failed to respond to that treatment. Although this persistent EEG activity appears likely to reflect GKS-induced brain changes, its relation to GKS seizure outcome remains unclear.