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To conduct a systematic review of the literature regarding rates and predictors of favorable seizure outcome after resective surgery for epileptic spasms (ES) in pediatric patients. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses standards were followed. We searched PubMed, EMBASE, and Cochrane CENTRAL for articles published on the prevalence or incidence of epileptic spasm since 1985. Abstract, full-text review, and data extraction were conducted by two independent reviewers. Meta-analysis was performed to assess overall seizure freedom rate. Subject-level analysis was performed on a subset of studies to identify prognostic indicators. A total of 21 retrospective studies (n = 531) were included. Meta-analysis of all studies demonstrated a pooled seizure freedom rate of 68.8%. Subject-level analysis on 18 studies (n = 360) demonstrated a significant association between duration of spasms and recurrence of spasms after surgery, with an estimated increased risk of 7% per additional year of spasms prior to operation. Patients who underwent resective surgery that was not a hemispherectomy (i.e., lobectomy, lesionectomy, etc.) had an increased recurrence risk of 57% compared to patients who had undergone hemispherectomy. Resective surgery results in seizure freedom for the majority of pediatric patients with epileptic spasms. Patients who undergo hemispherectomy have lower risk of recurrence than patients who undergo other types of surgical resection. Increased duration of spasms prior to surgery is associated with increased recurrence risk after surgery. PLAIN LANGUAGE SUMMARY: Children with epileptic spasms (ES) that do not respond to medications may benefit from surgical treatment. Our study reviewed existing research to understand how effective surgery is in treating ES in children and what factors predict better outcomes. Researchers followed strict guidelines to search for and analyze studies published since 1985, finding 21 studies with a total of 531 patients. They found that, on average, nearly 70% of children became seizure-free after surgery. Further individual analysis of 360 patients showed that longer duration of spasms before surgery increased the risk of spasms returning by 7% per year. Additionally, children who had less extensive surgeries, such as removal of only a specific part of the brain, had a 57% higher risk of seizure recurrence compared to those who had a hemispherectomy, which removed or disconnected half of the brain. Overall, the study concludes that surgery can often stop seizures, especially when more extensive surgery is performed and when the surgery is done sooner rather than later., (© 2024 The Author(s). Epilepsia Open published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.)

Introduction: Infantile epileptic spasms syndrome (IESS) is a common developmental and epileptic encephalopathy with poor long-term outcomes. A substantial proportion of patients with IESS have a potentially surgically remediable etiology. Despite this, epilepsy surgery is underutilized in this patient group. Some surgically remediable etiologies, such as focal cortical dysplasia and malformation of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE), are under-diagnosed in infants and young children. Even when a surgically remediable etiology is recognised, for example, tuberous sclerosis or focal encephalomalacia, epilepsy surgery may be delayed or not considered due to diffuse EEG changes, unclear surgical boundaries, or concerns about operating in this age group., Areas Covered: In this review, the authors discuss the common surgically remediable etiologies of IESS, their clinical and EEG features, and the imaging techniques that can aid in their diagnosis. They then describe the surgical approaches used in this patient group, and the beneficial impact that early epilepsy surgery can have on developing brain networks., Expert Opinion: Epilepsy surgery remains underutilized even when a potentially surgically remediable cause is recognized. Overcoming the barriers that result in under-recognition of surgical candidates and underutilization of epilepsy surgery in IESS will improve long-term seizure and developmental outcomes.

Objective: Epileptic Encephalopathy / Developmental Epileptic Encephalopathy with spike-and-wave activation during sleep (EE/DEE-SWAS) is a self-limiting childhood epilepsy syndrome but may cause permanent neurocognitive impairment. Surgical interventions have been controversial in the treatment of EE/DEE-SWAS. This systematic review aims to evaluate the efficacy of various surgical procedures on the outcomes of EE/DEE-SWAS., Methods: A systematic review was performed per the PRISMA guidelines. A total of 14 retrospective studies were identified, comprising 131 cases of EE/DEE-SWAS treated with epilepsy surgery. The review analyzed presurgical data, surgical interventions, as well as outcomes related to seizures, EEG, and neuropsychological assessments., Results: Epilepsy surgery was successfully performed in 131 cases with minor complications. The average age was 2.6 years at seizure onset and 5.0 years at diagnosis of SWAS. Excellent seizure control (Engel I and II) was achieved in 80.6 %, 78.6 %, 77.4 % and 27.2 % of patients receiving hemispherectomies, focal resections, multiple subpial transections (MSTs), and corpus callosotomies (CCTs), respectively. EEG SWAS resolution was seen in 79.7 % of hemispherectomy cases, 78.6 % in focal resections, 63.9 % in MSTs, and 8.3 % in CCTs. Neurocognitive and behavioral improvement was noted in 58.0 %, 71.4 %, 58.3 % and 16.7 % for patients receiving hemispherectomies, focal resections, MSTs, and CCTs, respectively. A correlation between improved seizure control and SWAS resolution was observed with improved neuropsychological outcomes., Conclusion: Epilepsy surgery is a safe and effective treatment for carefully selected children with drug-resistant EE/DEE-SWAS. Patients who underwent epilepsy surgery had reduction of seizure burden, SWAS resolution and improvements in neurocognitive and behavioral function., Competing Interests: Declaration of competing interest The authors report no conflicts of interest., (Copyright © 2024 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

Developmental and epileptic encephalopathies (DEEs) present significant treatment challenges due to frequent, drug-resistant seizures and comorbidities that impact quality of life. DEEs include both developmental encephalopathy from underlying pathology and epileptic encephalopathy where seizures exacerbate cognitive and behavioral impairments. Classification by syndrome and etiology is essential for therapy and prognosis, with common syndromes like infantile epileptic spasms syndrome and Dravet syndrome having specific first-line treatments. Etiologies are predominantly genetic, structural, or combined, with targeted therapies increasingly available. Surgery aims to improve seizure control but also may improve development, if the epileptic encephalopathy can be ameliorated. Timely intervention can reduce seizures and epileptiform discharges, maximizing developmental potential and allowing reduction in antiseizure medication. In cases requiring extensive resections, new deficits may be offset by developmental gains. Studies indicate that parents are generally willing to accept some deficits for significant seizure reduction., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

We represent the case of a premature twin neonate born from uncomplicated pregnancy who developed seizures at the age of 24 h. Two-dimensional ultrasound and magnetic resonance imaging revealed left-sided hemimegalencephaly. Further extensive diagnostic evaluation revealed a diagnosis of Ohtahara syndrome. Resistance of the seizures to antiepileptic therapy led to hemispherotomy that was performed at the age of 10 months. Our patient is now a 4-year-old child, walking, eating without a nasogastric tube, still with right hemiparesis and lateral strabismus but without seizures., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, ein Teil von Springer Nature.)

Objectives: Although hemispheric surgeries are among the most effective procedures for drug-resistant epilepsy (DRE) in the pediatric population, there is a large variability in seizure outcomes at the group level. A recently developed HOPS score provides individualized estimation of likelihood of seizure freedom to complement clinical judgement. The objective of this study was to develop a freely accessible online calculator that accurately predicts the probability of seizure freedom for any patient at 1-, 2-, and 5-years post-hemispherectomy., Methods: Retrospective data of all pediatric patients with DRE and seizure outcome data from the original Hemispherectomy Outcome Prediction Scale (HOPS) study were included. The primary outcome of interest was time-to-seizure recurrence. A multivariate Cox proportional-hazards regression model was developed to predict the likelihood of post-hemispheric surgery seizure freedom at three time points (1-, 2- and 5- years) based on a combination of variables identified by clinical judgment and inferential statistics predictive of the primary outcome. The final model from this study was encoded in a publicly accessible online calculator on the International Network for Epilepsy Surgery and Treatment (iNEST) website (https://hops-calculator.com/)., Results: The selected variables for inclusion in the final model included the five original HOPS variables (age at seizure onset, etiologic substrate, seizure semiology, prior non-hemispheric resective surgery, and contralateral fluorodeoxyglucose-positron emission tomography [FDG-PET] hypometabolism) and three additional variables (age at surgery, history of infantile spasms, and magnetic resonance imaging [MRI] lesion). Predictors of shorter time-to-seizure recurrence included younger age at seizure onset, prior resective surgery, generalized seizure semiology, FDG-PET hypometabolism contralateral to the side of surgery, contralateral MRI lesion, non-lesional MRI, non-stroke etiologies, and a history of infantile spasms. The area under the curve (AUC) of the final model was 73.0%., Significance: Online calculators are useful, cost-free tools that can assist physicians in risk estimation and inform joint decision-making processes with patients and families, potentially leading to greater satisfaction. Although the HOPS data was validated in the original analysis, the authors encourage external validation of this new calculator., (© 2023 The Authors. Epilepsia published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.)

Background: Infantile epileptic spasms syndrome is an epileptic encephalopathy, characterized by spasms, hypsarrhythmia, and developmental regression. Appropriately selected patients with infantile epileptic spasms syndrome may be candidates for epilepsy surgery. Methods: This is a single-center retrospective case series of children 0-18 years with a current or previous diagnosis of infantile epileptic spasms syndrome with a lesion on magnetic resonance imaging (MRI) and/or positron emission tomography scan who underwent epilepsy surgery at The Hospital for Sick Children (HSC) in Toronto, Canada. The records of 223 patients seen in the infantile epileptic spasms syndrome clinic were reviewed. Results: Nineteen patients met inclusion criteria. The etiology of infantile epileptic spasms syndrome was encephalomalacia in 6 patients (32%), malformations of cortical development in 12 patients (63%), and atypical hypoglycemic injury in 1 patient (5%). Nine patients (47%) underwent hemispherectomy, and 10 patients (53%) underwent lobectomy/lesionectomy. Three patients (16%) underwent a second epilepsy surgery. Fifteen patients (79%) were considered ILAE seizure outcome class 1 (completely seizure free; no auras) at their most recent follow-up visit. The percentage of patients who were ILAE class 1 at most recent follow-up decreased with increasing duration of epilepsy prior to surgery. Developmental outcome after surgery was improved in 14 of 19 (74%) and stable in 5 of 19 (26%) patients. Conclusions: Our study found excellent seizure freedom rates and improved developmental outcomes following epilepsy surgery in patients with a history of infantile epileptic spasms syndrome with a structural lesion detected on MRI brain. Patients who undergo surgery earlier have improved seizure freedom rates and improved developmental outcomes.

Objective: It has been suggested that asymmetric hypsarrhythmia is associated with structural etiology. We devised the Hypsarrhythmic Asymmetric Scoring Scheme (HASS) to quantify the degree of hypsarrhythmic asymmetry in a retrospective series of patients who underwent surgical treatment at our center. The present study aimed to investigate the role of HASS in predicting the postsurgical seizure outcomes., Methods: We retrospectively analyzed the records of 46 children with hypsarrhythmia who underwent resective epilepsy surgery between 2018 and 2020 and were followed up for at least 1 year after surgery. Hypsarrhythmia severity in each hemisphere was quantified and scored. The HASS score was calculated as the difference between the two hemispheres. Univariate results were submitted to logistic regression models to identify independent predictors for favorable surgical outcomes., Results: Of the 46 patients who underwent resective surgery, Engel's class I-Ⅱ outcomes were achieved in 34 (73.9%). The Engel I-Ⅱ group had a significantly higher HASS score than the Engel Ⅲ-Ⅳ group (p<0.001). Multivariate analysis showed that the HASS score was the only significant predictor of good outcomes (p = 0.011). Further receiver operating characteristic analysis showed that a threshold of 7 yielded a better seizure outcome with a sensitivity of 97.06% and specificity of 83.33%., Significance: As the first hypsarrhythmia scoring system specially designed for presurgical evaluation, the HASS score may contribute to predicting the postsurgical seizure outcome from the electroencephalography perspective., Competing Interests: Declaration of Competing Interest None of the authors have any conflicts of interest to disclose., (Copyright © 2022. Published by Elsevier Ltd.)

Objective: This retrospective study was designed to observe differences in ictal movements of epileptic spasm (ES) before and after corpus callosotomy (CC). We hypothesized that asymmetric expression of ES is more clarified after CC and would be a good indicator for the epileptic hemisphere., Methods: We selected 16 patients with intractable ES in West syndrome who were seizure-free after CC and subsequent resection or disconnective surgery of the unilateral hemisphere. We retrospectively reviewed their behavioral ES recorded at video-electroencephalography monitoring before and after CC. Asymmetric neck flexion (NF) and involuntary muscular contraction of the upper and lower extremities (MCU and MCL, respectively) were primarily described correlating their laterality and the responsible hemisphere proved by surgical resection., Results: Asymmetric NF, MCU, and MCL could be found both before and after CC. However, the percentage of those movements to the total number of ES increased after CC; asymmetric NF, 82.9% vs. 20.1%; unilaterally predominant MCU, 81% vs. 39.3%; and unilaterally predominant MCL, 77.6% vs. 29.9%. Regarding asymmetric NF, the direction in which the neck flexed or the head turned was significantly ipsilateral to the responsible hemisphere in 9 of 12 patients after CC (75%). The predominant side of MCU and MCL were significantly contralateral to the responsible hemisphere in 11 of 11 and 7 of 9 patients (100% and 77.8%, respectively)., Significance: Asymmetric NF, MCU, and MCL were clarified in patients with ES who were successfully treated with CC and subsequent surgery. Those changes in ictal behaviors after CC may indicate the lateralization of epileptic activity and encourage more curative surgical treatment., (© 2022 The Authors. Epilepsia Open published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.)

Objective: To determine the structural networks that constrain propagation of ictal oscillations during epileptic spasm events, and compare the observed propagation patterns across patients with successful or unsuccessful surgical outcomes., Methods: Subdural electrode recordings of 18 young patients (age 1-11 years) were analyzed during epileptic spasm events to determine ictal networks and quantify the amplitude and onset time of ictal oscillations across the cortical surface. Corresponding structural networks were generated with diffusion magnetic resonance imaging (MRI) tractography by seeding the cortical region associated with the earliest average oscillation onset time, and white matter pathways connecting active electrode regions within the ictal network were isolated. Properties of this structural network were used to predict oscillation onset times and amplitudes, and this relationship was compared across patients who did and did not achieve seizure freedom following resective surgery., Results: Onset propagation patterns were relatively consistent across each patient's spasm events. An electrode's average ictal oscillation onset latency was most significantly associated with the length of direct corticocortical tracts connecting to the area with the earliest average oscillation onset (p < .001, model R 2  = .54). Moreover, patients demonstrating a faster propagation of ictal oscillation signals within the corticocortical network were more likely to have seizure recurrence following resective surgery (p = .039). In addition, ictal oscillation amplitude was associated with connecting tractography length and weighted fractional anisotropy (FA) measures along these pathways (p = .002/.030, model R 2  = .31/.25). Characteristics of analogous corticothalamic pathways did not show significant associations with ictal oscillation onset latency or amplitude., Significance: Spatiotemporal propagation patterns of high-frequency activity in epileptic spasms align with length and FA measures from onset-originating corticocortical pathways. Considering the data in this individualized framework may help inform surgical decision-making and expectations of surgical outcomes., (© 2022 International League Against Epilepsy.)

Objective: Prior surgical series in children with drug-resistant epileptic spasms have reported use of intracranial EEG monitoring in up to two-third of patients. We report outcome after epilepsy surgery for drug-resistant epileptic spasms in a cohort of children without the use of intracranial EEG monitoring in any of the patients., Methods: Medical records of all consecutive children aged 5 years or under who had epilepsy surgery for epileptic spasms at Cleveland Clinic between 2000 and 2018 were reviewed. Post-operative seizure outcome and predictors of prognosis of seizure outcome were analyzed., Results: Seventy children with active epileptic spasms underwent surgical resections during the study period. Mean age at seizure onset was 6.8 (+9.31) months and median age at surgery was 18.5 months. An epileptogenic lesion was identified on brain MRI in all patients; 17 (24%) had bilateral abnormalities. Etiologies included malformations of cortical development (58%), perinatal infarct/encephalomalacia (39%), and tumor (3%). None of the patients had intracranial EEG. Surgical procedures included hemispherectomy (44%), lobectomy/ lesionectomy (33%), and multilobar resections (23%). Twelve children needed repeat surgery; six (50%) became seizure free after the second surgery. At six months follow-up, 73% (51/70) were seizure-free since surgery. At a mean follow-up of 4.7 years, 60% (42/70) had Engel 1 outcome. In those with seizure recurrence, 17 (60%) reported improvement. Shorter epilepsy duration (p = 0.05) and lobar or sub-lobar epileptogenic lesions (p = 0.02) predicted favorable seizure outcome at 6 months after surgery. For long term outcome, patients with bilateral abnormalities on MRI (p = 0.001), and multilobar extent on MRI (p = 0.02) were at higher risk for recurrence., Significance: Children with drug-resistant epileptic spasms secondary to an epileptogenic lesion detected on MRI could be selected for epilepsy surgery without undergoing intracranial EEG monitoring. A surgical selection paradigm without intracranial monitoring may allow early surgery without the risks of invasive monitoring., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The understanding and management of epileptic spasms has considerably evolved since the mid 19th century. The realization that epileptic spasms can be generated from a focal brain lesion played a pivotal role in the development of neurosurgical management for intractable forms of this epilepsy. During pre-surgical planning, the addition of functional FDG PET imaging has further refined the electroencephalographic localization of epileptogenic lesions. In some cases, neurosurgical resection of a focus that is co-localized by the FDG PET scan and electroencephalography can lead to partial or complete reversal of developmental delay along with reduced seizure frequency or seizure freedom. In cases where near-complete hemispheric cortex is implicated in spasm generation, subtotal hemispherectomy has shown encouraging results. Moreover, palliative resection of the major perpetrating focus in carefully chosen patients with bilateral multifocal spasms has also led to favorable outcomes. However, in patients with tuberous sclerosis with high tuber burden, the localizing value of FDG PET imaging may be limited. In such cases, employment of AMT PET technology has become a valuable tool for localization of actively epileptogenic tubers. This article highlights the historic steps in the successful advancements of neurosurgical interventions for the treatment of intractable epileptic spasms., (Copyright © 2016. Published by Elsevier Inc.)

We aimed to analyse the ictal electrographic changes on scalp electroencephalography (EEG), focusing on high-voltage slow waves (HVSs) in children with epileptic spasms (ES) and tonic spasms (TS) and then identified factors associated with corpus callosotomy (CC) outcomes. We enrolled 17 patients with ES/TS who underwent CC before 20 years of age. Post-CC Engel's classification was as follows: I in 7 patients, II in 2, III in 4, and IV in 4. Welch's t-test was used to analyse the correlation between ictal HVSs and CC outcomes based on the following three symmetrical indices: (1) negative peak delay: interhemispheric delay between negative peaks; (2) amplitude ratio: interhemispheric ratio of amplitude values for the highest positive peaks; and (3) duration ratio: interhemispheric ratio of slow wave duration. Ages at CC ranged from 17-237 months. Four to 15 ictal EEGs were analysed for each patient. The negative peak delay, amplitude ratio and duration ratio ranged from 0-530 ms, 1.00-7.40 and 1.00-2.74, respectively. The negative peak delay, amplitude ratio and duration ratio were significantly higher in the seizure residual group (p = 0.017, <0.001, <0.001, respectively). Symmetry of ictal HVSs may predict favourable outcomes following CC for ES/TS.

Objective: We analyzed the features of fast oscillations (FOs) and connectivity in hypsarrhythmia to identify biomarkers for predicting seizure outcomes after total corpus callosotomy (TCC) in children with pharmacoresistant infantile spasms (IS). We hypothesize that the power of FOs and connectivity of slow waves in hypsarrhythmia would indicate the prognosis of IS., Method: We retrospectively identified 42 children with pharmacoresistant IS who underwent TCC from 2009 to 2014 at Nagasaki Medical Center. We collected preoperative hypsarrhythmia for 200 seconds from each child. Children were categorized into three groups with interictal epileptic discharges on EEG at 6 months after TCC: group A, no epileptic discharge; group B, lateralized epileptic discharges; and group C; bilateral epileptic discharges. We analyzed spectral power and phase synchronization in preoperative hypsarrhythmia among the three groups., Results: We found 10 children in group A, 10 children in group B, and 22 children in group C. All group A and 1 in group B achieved seizure freedom after TCC. Six (67%) of 9 group B children who underwent further surgeries achieved seizure freedom. Ten (45%) of group C children had seizure reduction >50% after TCC, and 13 (87%) of 15 children who underwent further surgeries had residual seizures. The clinical profiles of the three groups did not differ significantly. The power of FOs (≥45 Hz) in hypsarrhythmia was significantly stronger in group C at the midline and temporal regions than in groups B and A (P = .014). The connectivity of theta (4-9 Hz) and FOs (29-70 Hz) tended to increase in group C, compared with the increased connectivity of 1-2 Hz in group A (P = .08)., Significance: The increased power and connectivity of FOs in hypsarrhythmia may correlate with pharmacoresistant and surgically resistant seizures in IS. The existence and connectivity of FOs are associated with unilateral/bilateral cortical epileptogenicity in hypsarrhythmia. Prominent slow waves and connectivity without FOs might correlate with seizure freedom after TCC. Modulation of the callosal system with subcortical/cortical epileptic discharges might play a role in generating hypsarrhythmia and IS., (Wiley Periodicals, Inc. © 2019 International League Against Epilepsy.)

Background: Corpus callosotomy (CC) has recently been adopted for the treatment of drug-resistant epileptic spasms and tonic spasms. In the present study, we investigated CC outcomes among patients with drug-resistant epileptic spasms or tonic spasms associated with tuberous sclerosis complex (TSC)., Methods: We retrospectively collected data from seven patients (3 women, 4 men) with diagnosed TSC and who were treated using CC at Seirei Hamamatsu General Hospital in Japan. All patients had experienced drug-resistant epileptic spasms (<3 s of muscular contraction) or tonic spasms (>3 s) prior to CC, which were confirmed via video-electroencephalogram monitoring., Results: All patients exhibited multiple bilateral cortical tubers on brain magnetic resonance imaging. The main seizure types were epileptic spasms in four, tonic spasms in one, and both seizure types in two patients. Patients underwent total CC between the ages of 25 months and 21.5 years. Additional resection or disconnection was performed in two patients. The follow-up period after CC ranged between 9 months and 3.5 years. Three patients achieved remission from spasms following CC alone. Two other patients became free from spasms several months after CC but required an additional focus disconnection or medical treatment. The remaining two patients continued to show spasms or asymmetrical tonic seizures., Conclusion: Total CC resulted in freedom from drug-resistant epileptic or tonic spasms in several patients with TSC. Stepwise progression from CC to additional resection or disconnection surgery may aid in the treatment of spasms secondary to TSC., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objective: This retrospective study was designed to assess the impact of corpus callosotomy (CC) in patients with intractable West syndrome (WS) without lesions on magnetic resonance imaging (MRI)., Methods: This study involved 56 patients with WS who underwent CC between January 2000 and December 2014. Seizure outcomes and changes in psychomotor development were analyzed., Results: Mean age at the onset of epilepsy and at the time of CC was 5.1 and 22.6 months, respectively. Mean duration of epilepsy before CC was 17.6 months. Video-electroencephalography (EEG) monitoring showed bilateral ictal and interictal abnormalities before CC. Mean follow-up duration was 36.6 months. At final follow-up, seizure outcomes after CC were seizure-free in 18 patients (32.1%), excellent (E: >80% reduction in seizure frequency) in 15 (26.8%), good (G: >50% reduction) in 10 (17.9%), and poor (P: <50% reduction) in 13 (23.2%). Epileptic spasms (ES) were eliminated in 24 patients (42.9%). However, tonic seizure (TS) outcomes were poor (P < 0.05). Of preoperative predictive factors related to seizure outcome, developmental delay before epilepsy onset correlated with poor outcome (P < 0.05). One year post-CC, 6 patients (10.7%) had no epileptic abnormality on EEG, 19 (33.9%) had lateralized epileptic abnormalities, and 31 (55.4%) had bilateral asynchronous epileptic abnormalities. All patients without epileptic discharge achieved seizure freedom. Fifteen of 19 (78.9%) patients in the lateralized group and 12 of 31 (38.7%) in the bilateral asynchronous group had worthwhile outcomes (F + E). The patterns of EEG changes after CC correlated with seizure outcome (P < 0.01). Progressive declines in developmental quotient were prevented in patients with worthwhile outcomes., Significance: CC represents an important therapeutic option for patients with WS without resectable MRI lesions. Transcallosal seizure bilateralization is critical for bilateral ES generation. Early identification of potential CC candidates and surgical intervention are important for better seizure control and cognitive capacity preservation before severe developmental delay development., (Wiley Periodicals, Inc. © 2018 International League Against Epilepsy.)

We report a 10-month-old boy with treatment-resistant infantile spasms associated with hypothalamic hamartoma (HH). Electroencephalography before surgical treatment showed modified hypsarrhythmia. Transventricular endoscopic resection and disconnection resulted in immediate and enduring disappearance of the epileptic spasms and improvement in the postoperative electroencephalography. After 8 years of treatment, the patient has nondisabling gelastic seizures associated with a small amount of residual HH but no other seizure types. He is not taking any antiepilepsy drugs. He is academically and socially successful. We are not aware of any prior reports of surgical treatment of HH with concurrent infantile spasms as an uncontrolled seizure type. The immediate disappearance of infantile spasms demonstrates that the HH lesion itself is an active and necessary component within the epileptic network responsible for spasms in this particular condition. This case contributes to the recognition that focal pathologies can be responsible for infantile spasms with hypsarrhythmia and respond successfully to surgical intervention., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Purpose: Infantile spasms (IS) can occur as the only seizure type in children with surgically amenable epilepsies. Although early surgery has shown positive effects, little is known regarding outcomes., Methods: We retrospectively reviewed all children with IS referred to our tertiary center between 2002 and 2014 and try to define factors of outcome., Results: Sixty-eight children with focal onset seizures were referred: twenty children with a hemispheric implication and 48 with one or more lobes involved. The age of onset was significantly earlier in the hemispheric population (8.0 versus 16.7 months in the focal population). There was no difference in the age of onset between anterior and posterior onset zones, as we could expect regarding the maturation gradient. The epilepsy began earlier in life in tuberous sclerosis than in DNET. Only three children of the 48 non-hemispheric patients had a normal MRI at the time of the surgery. Temporal lobe was involved only in a third of the population. More than 86% of the patients were operated on. Patients with hemispheric lesions were operated on younger (2.6 years+/- 2.1 years) compared to 4.6+/- 3.5 years in the whole population. The most frequent etiologies were in descending order: dysplasia, ganglioglioma or dysembryoplastic tumours and tuberous sclerosis. The global seizure outcome was favorable (Engel 1a) in 74.6% of the patients, and 87.9% if the delay between the first seizure and the surgery was less than 36 months. It fell to 64.7% if the delay exceeded 50 months., Conclusion: Spasms of focal onset have a similar postsurgical outcome as other seizure types so surgery may be an excellent option for treating selected patients with focal infantile spasms. Volume and type but not topography of the lesion influence the age of onset. MRI is very helpful to locate the pathology in the pediatric population, since only a small portion had a normal MRI., (Copyright © 2017 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: Traditionally, seizure onset localization in ictal electro-encephalography (EEG) is the main factor guiding resective epilepsy surgery. The situation is often different in infantile epileptic encephalopathy. We demonstrate the importance of the underrated interictal (rather than ictal) surface EEG in informing decision-making in epilepsy surgery for children with epileptic encephalopathy caused by subtle focal cortical dysplasia (FCD)., Methods: We present a small case series of three children who had an epileptic encephalopathy with either epileptic spasms or tonic seizures. All three were thought initially to have normal neuroimaging., Results: Ictal EEG localizing features were seen in none and lateralizing features were seen only clinically in one of the three. However, the interictal EEG showed persistent and consistent focal irregular slowing in all, particularly after medically resolving the diffuse encephalopathy. Subtle FCDs were uncovered in all. Surgery was performed in all with excellent outcome., Conclusion: In infantile epileptic encephalopathy caused by subtle FCD, the often underrated interictal surface EEG (particularly persistent foal irregular slowing) informs the most; not only to the target area for surgical resection but also to its extent. This may negate the need for unnecessary and sometimes non-informative invasive monitoring in these cases. A matter of "zooming out" to define the extent of a resectable abnormality rather than "zooming in" to define a seemingly localized epileptic focus that may change with time.

We report a patient with intractable West syndrome whose epileptic spasms (ESs) were initially bilaterally synchronous, as is typical; after a complete corpus callosotomy, however, bilaterally independent ESs originated in either hemisphere. Activity of probable cortical origin associated with ESs was detected by observing ictal gamma oscillations. Brain MRI revealed no structural abnormality before surgery. This case suggests that ESs with a hemispheric origin may appear generalized because of synchronizing effects in the corpus callosum in some patients., (Copyright © 2015 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.)

Background: Focal status epilepticus and catastrophic epilepsy are not rare in infants. Epilepsy surgery can be safely done in selected infants to cure epilepsy., Patient Description: We report on an infant who began having drug-resistant status epilepticus at 2 weeks of age and developed epileptic spasms. We discuss in detail how the clinical and electroencephalographic data were used to reach a consensus for epilepsy surgery and why a particular surgical approach was preferred over other alternatives., Method: Presurgical evaluation consisted of 32-channel scalp video EEG using the standard 10-20 system of electrodes, 3-Tesla brain magnetic resonance imaging, and 18 F-fluorodeoxyglucose positron emission tomography. The surgery consisted of resection of the extensive epileptogenic lesion, in addition to disconnection of the left frontal lobe anterior to the motor strip., Result: The infant underwent epilepsy surgery at three months of age. At two-year follow up, she remained seizure free, with no focal motor deficit and the epileptic encephalopathy resolved. The disconnected left frontal lobe shows epileptiform discharges restricted to the disconnected tissue., Conclusion: We highlight the importance of epilepsy surgery in selected infants to achieve seizure freedom and to reverse epileptic encephalopathy. In the process, we demonstrate how epileptic spasms, although clinically and electrographically generalized, resolved after disconnecting the epileptogenic zone.

Objective: We reviewed our experience of surgery for epileptic spasms (ES) with or without history of infantile spasms., Methods: Data were reviewed from 65 (33 male) patients with ES who underwent surgery between 1993 and 2014; palliative cases were excluded., Results: Mean age at surgery was 5.1 (range 0.2-19) years, with mean postsurgical follow-up of 45.3 (6-120) months. Mean number of anticonvulsants used preoperatively was 4.2 (2-8), which decreased to 1.2 (0-4) postoperatively (p < 0.0001). Total hemispherectomy was the most commonly performed surgery (n = 20), followed by subtotal hemispherectomy (n = 17), multilobar resection (n = 13), lobectomy (n = 7), tuberectomy (n = 6), and lobectomy + tuberectomy (n = 2), with International League Against Epilepsy (ILAE) class I outcome in 20, 10, 7, 6, 3, and 0 patients, respectively (total 46/65 (71%); 22 off medication). Shorter duration of epilepsy (p = 0.022) and presence of magnetic resonance imaging (MRI) lesion (p = 0.026) were independently associated with class I outcome. Of 34 patients operated <3 years after seizure onset, 30 (88%) achieved class I outcome. Thirty-seven (79%) of 47 patients with lesional MRI had class-I outcome, whereas 9 (50%) of 18 with normal MRI had class I outcome. Positron emission tomography (PET) scan was abnormal in almost all patients [61 (97%) of 63 with lateralizing/localizing findings in 56 (92%) of 61 patients, thus helping in surgical decision making and guiding subdural grid placements, particularly in patients with nonlesional MRI. Fifteen patients had postoperative complications, mostly minor., Significance: Curative epilepsy surgery in ES patients, with or without history of infantile spasms, is best accomplished at an early age and in those patients with lesional abnormalities on MRI with electroencephalography (EEG) concordance. Good outcomes can be achieved even when there is no MRI lesion but positive PET localization., (Wiley Periodicals, Inc. © 2015 International League Against Epilepsy.)

Background: Infantile spasms (IS) are a severe epileptic encephalopathy. In patients with early focal ischemia and refractory IS, a preoperative evaluation is required even if IS are the only ictal manifestation., Methods: We report three such patients who presented with IS between 5 and 7 months of age without any other focal seizure types. Imaging exhibited a perinatal middle cerebral artery (MCA) stroke., Results: All patients had hemiparesis and experienced psychomotor regression after the onset of IS. Scalp video-electroencephalogram (EEG) monitoring for presurgical assessment showed interictal and ictal EEG characteristics between the pathological and the healthy hemisphere and surgery was proposed despite the lack of any focal seizures. The three patients underwent hemispherotomy at a mean age of 27 months and became seizure-free without medication (follow-up 49-144 months). The two patients who underwent early hemispherotomy acquired normal verbal intelligence, whereas the third, operated on at 38 months of age, remained with severe mental retardation., Conclusion: Early hemispherotomy in drug-resistant epilepsy related to a perinatal MCA may cure the seizures even if the patient has IS as sole type and prevent mental retardation in some children., (Copyright © 2015 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.)

Traditionally, identification of epileptogenic zones primarily relied on visual inspection of intracranial electroencephalography (iEEG) recordings by experienced epileptologists; however, removal of epileptogenic zones identified by iEEG does not always guarantee favorable surgical outcomes. To confirm visual inspection results, and assist in making decisions about surgical resection areas, computational iEEG analysis methods have recently been used for the localization of epileptogenic zones. In this study, we have proposed a new approach for the localization of epileptogenic zones in Lennox-Gastaut syndrome (LGS), and have investigated whether the proposed approach could confirm surgical resection areas and predict seizure outcome before surgery. The proposed approach simultaneously used results of 2 iEEG analysis methods, directed transfer function (DTF) and time delay estimation, to enhance localization accuracy. This new combined method was applied to patients who became seizure-free after resective epilepsy surgery, as well as those who had unsuccessful surgery. A quantitative metric was also introduced that can measure how well the localized epileptogenic zones coincided with the surgical resection areas, with the aim of verifying whether the approach could confirm surgical resection areas determined by epileptologists. The estimated epileptogenic zones more strongly coincided with surgical resection areas in patients with successful, compared to those with unsuccessful surgical outcomes. Both qualitative and quantitative analyses showed that the combined use of 2 iEEG analyses resulted in a more accurate estimate of epileptogenic zones in LGS than the use of a single method. A combination of multiple iEEG analyses could not only enhance overall accuracy of localizing epileptogenic zones in LGS, but also has the potential to predict outcomes before resective surgery.

Purpose: to evaluate the outcomes and role of epilepsy surgery in children with intractable epileptic encephalopathy (EE)., Methods: ninety-five children (64 boys, 31 girls) with intractable EE were treated by epilepsy surgery at Severance Children's Hospital from 2003 to 2008. Surgical treatments included lobar resection, hemispherotomy and corpus callosotomy (CC). Seventy-six children were Lennox-Gastaut syndrome (LGS), and 19 had West syndrome., Results: of the 76 patients with LGS, CC was performed in 37 patients (48.7%), lobar resection in 29 (38.2%) and hemispherotomy in 10 (13.2%). Of the 19 patients with West syndrome, respective surgery was performed in 15 patients (78.9%) and CC in 4 (21.1%). Of the patients receiving respective surgery, Engel's class I outcomes were achieved for 24 of 39 (61.5%) of LGS patients, and for 9 of 15 (60.0%) of West syndrome. Malformations of cortical development were commonly observed, appearing in 73.5% (36/49). In neuropsychiatric tests, 19 of 27 with LGS demonstrated improvement in postoperative cognitive function. More significant intellectual improvement correlated well with shorter epilepsy duration, good seizure outcomes, and decreased number of antiepileptic drugs., Conclusions: epilepsy surgery should be considered in treating childhood intractable EE with expectation of improvement of both seizure and cognitive outcomes, even in cases of LGS., (Copyright © 2013. Published by Elsevier B.V.)

Early infantile epileptic encephalopathy or Ohtahara syndrome is the earliest form of the age-dependent epileptic encephalopathies. Its manifestations include tonic spasms, focal motor seizures, suppression burst pattern, pharmaco-resistance, and dismal prognosis. The purpose of this study was to evaluate the effectiveness of epilepsy surgery in selected infants. We identified 11 patients, 9 from the literature and 2 from our institution that fulfilled diagnostic criteria of Ohtahara syndrome and had undergone epilepsy surgery in infancy. Seven of the 11 infants have remained seizure free (Engel class IA) and four are reportedly having rare to infrequent seizures (Engel class IIB). All patients experienced "catch up" development. In contrast to Ohtahara's15 pharmacotherapy managed patients, who had a mortality rate of approximately fifty percent, and those that survived continued to have seizures and were severely impaired, the outcome of selected surgically managed patients is much more favorable.

Purpose: We present our experience with corpus callosotomy (CC) in a developing country with limited resources in patients with Lennox-Gastaut syndrome (LGS) and medically refractory seizures., Methods: All patients with LGS who underwent CC for medically refractory epilepsy at Namazee Hospital, Shiraz University of Medical Sciences, Shiraz, Iran from May 2009 through March 2012 were reviewed in a retrospective study. Presurgical evaluation included clinical history, neurological examination, a 2-hour video-EEG recording, and 1.5-T MRI. Outcome was evaluated at 6, 12, and 24 months postoperatively. We considered the outcome as a success if the patients were either seizure-free or had more than 85% reduction in seizure frequency compared to their preoperative status., Results: Eighteen patients (14 males and 4 females) had surgery. Overall, seizures in 11 patients (61.1%) responded favorably one year after surgery; this figure was 6 out of 9 patients (66.6%) two years after surgery. Seven patients (38.8%) were free of disabling seizures one year after CC; this figure was three out of nine patients (33.3%) two years after CC. Three patients (16.6%) were free of all seizure types one year after surgery. Ten patients (55.5%) had no postoperative complications of any kind., Conclusion: Corpus callosotomy is an effective palliative surgical procedure for patients with LGS with intractable seizures whose seizures are not amenable to focal resection. This is a feasible treatment option for patients, even for those in developing countries with limited resources., (© 2013.)

Purpose: This study sought to evaluate the seizure outcome of infantile spasms (IS) with focal cortical dysplasia (FCD)., Methods: We retrospectively reviewed infantile spasms patients with FCD from 2004 to 2010. We investigated seizure outcome from antiepileptic drug (AED), ketogenic diet (KD), resective surgery, and analyzed the results according to individual imaging studies., Results: Among 404 patients of IS, FCD was confirmed in 51 patients. In retrospective review of brain MRI, only 21 patients (41.2%) were suspected of FCD before 1year of age, but 45 patients (88.2%) became confirmed to FCD by MRI after the age of 1year. Once the spasms were not controlled by 1 or 2 AEDs, the chance of becoming seizure free with additional third or more drugs was very low (2.3%). The seizure free rate was 33.3% (7/21) in patients treated with ketogenic diet, and 73.3% (22/30) in surgical patients, who were both intractable to AEDs. There were no significant differences in seizure free rate in both ketogenic diet and surgical patients, between MRI negative and positive patients prior to 1year of age., Conclusions: KD and surgery should be considered in medically refractory IS with FCD., (Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.)

Background: Lennox-Gastaut syndrome is a catastrophic childhood cryptogenic or symptomatic epilepsy. Hypothalamic hamartomas cause refractory epilepsy often consistent with Lennox-Gastaut syndrome., Methods: Children with Lennox-Gastaut syndrome were defined by a triad of multiple generalized seizure types, slow spike-and-wave on EEG, and mental retardation., Results: Twenty-one of 159 hypothalamic hamartoma patients (14%) met the diagnostic criteria of Lennox-Gastaut syndrome. The median age of patients at epilepsy onset was 0.9 years (range, birth to 9 years). Six of the 21 patients (28%) had preceding infantile spasms. All patients underwent different surgical approaches, including endoscopic, transcallosal, orbitozygomatic resections, and radiosurgery treatment. Five of the 21 (24%) were seizure free with an additional 9 (42%) having at least >90% seizure reduction. Only 1 patient was not effectively treated (<50% seizure reduction). Eighty-eight percent of parents reported improvement in behavioral functioning. Shorter duration of epilepsy prior to surgery was a significant predictor of surgical outcome., Conclusions: Patients with Lennox-Gastaut syndrome symptomatic to hypothalamic hamartomas have better postsurgical outcome due to other etiologies compared with cryptogenic and symptomatic Lennox-Gastaut syndrome patients. However, compared with overall hypothalamic hamartomas postsurgical outcomes, this cohort was less favorable. Earlier surgery may lead to better outcomes., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Purpose: Rufinamide is a novel antiepileptic drug (AED), which is known to be effective in the treatment of partial seizures and drop attacks in patients with Lennox-Gastaut syndrome (LGS). The aim of this study is to evaluate the efficacy and tolerability of rufinamide in those with LGS., Methods: Patients with LGS who had received rufinamide adjunctive therapy were enrolled in this study. We retrospectively reviewed these patient's baseline clinical characteristics, and the reduction of seizure frequency and adverse events after the use of rufinamide., Results: Twenty-three patients (15 males and 8 females, ages 4-22 years) were enrolled in the study. All the patients suffered from daily head drops and tonic seizures despite multiple antiepileptic drugs. After one month of rufinamide, one patient (4.3%) achieved freedom from seizures, ten (43.5%) achieved a ≥50% decrease in seizure frequency. After six months of rufinamide, eight patients (34.8%) maintained a satisfactory response (seizure free in one, and greater than 50% seizure reduction in seven). Adverse events were reported in six (26.0%) patients, which were somnolence in three, aggressive behavior in two, and aggravation of seizure in one patient., Conclusions: Our results suggest that rufinamide is effective and safe in children and young adults with LGS., (Copyright © 2012 Elsevier B.V. All rights reserved.)

We present the case of an 18-year-old girl with a scoliosis (long C-shaped curve) in association with an atypical Rett's syndrome. In order to attain a full correction and to provide her with adequate posture and sitting balance, segmental instrumentation was utilised from the high thoracic spine to the pelvis. We describe the procedure including the relevant pre-operative, intra-operative and post-operative imaging.

Extensive multilobar cortical dysplasias occasionally occur in children and can induce seizure onset in early infancy, causing severe epileptic encephalopathy. Surgical interventions in early infancy, such as disconnection of large parts of the brain, are challenging because of the degree of invasiveness and carry greater risks in infants compared with older children. Here we report the successful treatment of intractable epilepsy with multilobar cortical dysplasias in the posterior cortex by posterior disconnection in three infants (age 3 months). The patients showed good postoperative recovery and exhibited excellent seizure control at follow-up evaluation within a year after surgery. Developmental catch-up was also achieved and no early complications have been detected to date. Use of the posterior disconnection technique for early-stage extensive multilobar cortical dysplasias can result in good seizure control and developmental progress with little perioperative morbidity. However, the efficacy of this surgical technique needs to be verified with long-term follow up after surgery.

Objectives: High-frequency oscillations (HFOs) on intracranial electroencephalography (EEG) recordings have been reported to be useful to identify the epileptogenic zone in intractable epilepsy. We investigated whether the ictal HFOs on scalp EEG seen during spasms contributed to identification of the epileptogenic zone in symptomatic West syndrome (S-WS)., Methods: In S-WS, ictal scalp EEGs were recorded during a series of spasms. The HFOs associated with spasms were visualized in the temporally expanded EEG traces and subjected to time-frequency analysis. The results on the distribution of HFOs were compared with that of cortical lesions indicated by neuroimaging., Results: In the 4 children examined, HFOs at 80-150 Hz preceded the clinical onsets of spasms. The maximum augmentation of these HFOs was larger than that of HFOs at 20-70 Hz. The regions of the maximum augmentation of HFOs at 80-150 Hz were identical to the lesions detected by neuroimaging. Two patients who underwent dissection of the area including the area with HFOs resulted in Engel class I., Conclusion: Ictal HFOs of spasms on scalp EEG showed a strong association with neuroimaging abnormalities presumed to be the epileptogenic zone in S-WS. Ictal HFOs can thus be a useful marker for exploring lesions for epilepsy surgery., (Copyright © 2012 Elsevier B.V. All rights reserved.)

The efficacy of surgery for the treatment of epilepsy in patients with West syndrome secondary to tuberous sclerosis is unclear. The charts of 17 patients with tuberous sclerosis and secondary West syndrome who underwent a one-stage surgical resection with a combined palliative operative procedure were reviewed. Engel classification was used to classify the patients with regard to seizure status following surgery. After surgery, 11 patients were in Engel class I, 4 in class II, and 2 in class III. The EEG after surgery was normal in 8 patients, significantly improved in 8, and without significant improvement in 1 patient. Six patients had a recurrence of seizures after surgery, which included 3 patients with continuing spasms and 3 patients where the spasms had resolved but had developed either partial seizures or generalized tonic-clonic seizures. There were significant improvements in the Gesell Developmental Schedules for motor field (P=0.003), adaptive field (P=0.003), language field (P=0.033), and personal-social field (P=0.007). Thus, a one-stage surgical approach can be used to produce satisfactory outcomes in young children with tuberous sclerosis who have secondary West syndrome and seizures that do not respond to conventional antiepileptic therapy, even in when there are multiple epileptogenic foci., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Object: Corpus callosotomy is usually intended to alleviate-not to achieve total control of-epileptic seizures. A few patients experience complete seizure control after callosotomy, but the associated clinical factors are unknown. The object of this study was to investigate clinical factors associated with long-term seizure remission after total corpus callosotomy in patients with infantile or early childhood onset epilepsy., Methods: Thirteen consecutive patients with infantile or early childhood onset epilepsy underwent 1-stage total corpus callosotomy for alleviation of seizures. Their age at surgery ranged from 1 year and 5 months to 24 years (median 7 years). Eleven patients had West syndrome at the onset of disease, and the other 2 had Lennox-Gastaut syndrome. All patients suffered from spasms, axial tonic seizures, or atonic seizures. Six patients had proven etiology of epilepsy, including tuberous sclerosis, polymicrogyria, trauma, and Smith-Magenis syndrome. The association between postoperative seizure freedom and preoperative factors including age at surgery, no MRI abnormalities, proven etiology, and focal electroencephalographic epileptiform discharges was examined., Results: Postoperative seizure freedom was achieved in 4 of 13 patients for a minimum of 12 months. All 4 patients had no MRI abnormalities and no identified etiology. None of the 8 patients with MRI abnormality, 6 patients with known etiology of epilepsy, or 4 patients aged older than 10 years at surgery achieved seizure freedom. Two of the 7 patients with focal electroencephalographic abnormalities became seizure free. Absence of MRI abnormalities was significantly associated with postoperative seizure freedom (p < 0.01)., Conclusions: Complete seizure remission is achieved after total corpus callosotomy in a subgroup of patients with intractable epilepsy following West syndrome or Lennox-Gastaut syndrome. One-stage total corpus callosotomy at a young age may provide a higher rate of seizure freedom, especially for patients with no MRI abnormalities and no identified etiology of epilepsy.

We aimed to clarify the relationships between post-sectional recruitment of epileptiform discharges (PRED) seen in electrocorticograms (ECoG) during callosotomy in patients with Lennox-Gastaut syndrome (LGS) and postoperative seizure outcome. We retrospectively analyzed ECoG obtained during subtotal callosotomy (6 cm) in 48 patients with LGS (32 males, 16 females; age range, 1-20 years; mean age, 7.6 years) from July 1993 to November 1996 and compared recorded findings with postoperative seizure outcome. At analysis, all patients had been followed postoperatively for more than 10 years. Of 48 patients, 15 (31.3%) had PRED in their post-section ECoG. Of these patients, 11 (73%) achieved significant (at least 50%) overall seizure reduction postoperatively. The phenomenon of PRED in callosotomy did not predict a better postoperative seizure outcome (p>0.05). We concluded that post-sectional ECoG recruitment of electrical discharges during callosotomy did not predict postoperative prognosis. However, this finding should be supported and elucidated by further studies. The heterogenous ECoG findings during callosotomy in our series might suggest a complicated role of the corpus callosum in the epileptogenesis of Lennox-Gastaut syndrome., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Precise localization of ictal onset zones is of great clinical importance for successful surgery in patients with intractable drug-resistant epilepsy. Time delay analysis has been one of the most reliable and most widely used computational electroencephalogram (EEG) analysis methods for localizing ictal onset zones. However, the majority of previous studies have only been applied to the localization of ictal onset zones in focal epilepsy. In the present study, we analyzed intracranial EEG (iEEG) recordings acquired from patients with Lennox-Gaustaut syndrome (LGS), which is a type of intractable, pediatric, secondary generalized epilepsies with bilaterally synchronous ictal epileptiform discharges. To estimate the ictal onset zones from ictal iEEG recordings, we estimated time delays among iEEG signals based on the information theoretical approach. The results of the time delay analysis applied to the iEEG data of four successfully treated LGS patients corresponded well with the surgical resection areas identified by experienced epileptologists and multiple neuroimaging modalities, suggesting that the time delay analysis may provide useful information on the precise locations of ictal onset zones prior to epilepsy surgery in LGS patients., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Lennox-Gastaut syndrome (LGS) is a devastating and refractory generalized epilepsy affecting children and adolescents. In this study we report the results of resective surgery in 18 patients with LGS phenotype who underwent single-lobe/lesionectomy or multilobe resection plus multiple subpial transection and/or callosotomy. After surgery, seven patients became completely seizure-free (Engel Class I) and five almost seizure-free (Engel Class II). Additional four had significant seizure control (Engel Class III), and two had no change in seizure frequency (Engel Class IV). Of the 4 patients without any lesion on brain MRI, 2 ended with Engel Class II, 1 with III and the other with IV in Engels' classification. Mean intelligence quotient (IQ) increased from 56.1 ± 8.1 (mean ± SD) before operation to 67.4 ± 8.2 (mean ± SD) after operation, a significant improvement (P = 0.001). Results also indicated that the younger the patient at surgery, or the shorter the interval between onset of seizure and resective operation, the better the intellectual outcome. Our data suggest that resective epilepsy surgery can be successful in patients with LGS phenotype as long as the EEG shows dominance of discharges in one hemisphere and corresponding ipsilateral imaging findings, even with contralateral ictal discharges.

The authors report on the case of a 6-week-old boy who presented with infantile spasms. At 2.5 months of age, the patient underwent a right hemispherectomy. Approximately 3 months postoperatively, the patient presented with left coronal craniosynostosis. Subsequent cranial vault remodeling resulted in satisfactory cosmesis. Four years after surgery, the patient remains seizure free without the need for anticonvulsant medications. The authors believe this to be the first reported case of iatrogenic craniosynostosis due to hemispherectomy, and they describe 2 potential mechanisms for its development. This case suggests that, in the surgical treatment of infants with intractable epilepsy, minimization of brain volume loss through disconnection techniques should be considered, among other factors, when determining the best course of action.

Purpose: Corpus callosotomy (CC) is a palliative surgical procedure to control atonic, tonic, or generalized tonic-clonic seizure in Lennox-Gastaut syndrome (LGS). Here, we report patients with LGS who underwent resective surgery, following CC better delineating the presumed seizure foci localized in one hemisphere., Methods: We retrospectively reviewed seven patients with LGS who underwent CC and subsequent cortical resection. The median follow-up duration after lobectomy was 20 months (range, 15-54 months) and three patients had follow-up periods over 24 months. The findings of video electroencephalography (EEG) monitoring, structural and functional neuroimagings were compared between pre- and post-CC., Results: Four patients had Engel class I and one patient had Engel class II outcomes following cortical resection; post-CC, compared to pre-CC, showed better localized ictal/interictal epileptiform discharges in the unilateral frontal area in two patients, in the unilateral parieto-temporo-occipital areas in one patient and in the unilateral fronto-temporal areas in the remaining two patients. Two patients had Engel Class III outcome following cortical resection; post-CC EEG continued to show multifocal epileptiform discharges but predominantly arising from a unilateral frontal area. Following CC, positron emission tomography showed localized glucose hypometabolism of which location was concordant with post-CC EEG abnormalities in all patient. Similarly, ictal/interictal single photon emission computed tomography also showed localized abnormalities concordant with post-CC EEG abnormalities in five of the six patients. Pathological assessment revealed cortical dysplasia in six patients, whereas no pathological abnormality was found in the remaining patient, who obtained Engel Class I outcome following cortical resection., Conclusion: CC could change EEG findings, glucose metabolisms and cerebral blood flows, and it is sometimes helpful in delineating the primary seizure focus in patients with LGS., (Copyright © 2010 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.)

Lennox-Gastaut syndrome (LGS) is an intractable childhood-onset epileptic encephalopathy. Seizure freedom is rare in LGS. One of the hallmarks of LGS is medical intractability, with generally poor response to antiepileptic drugs (AEDs). Nevertheless, several treatment options are available that can mitigate the severity of seizures and curtail their frequency. New AEDs have been validated in randomized, controlled trials for the treatment of seizures in LGS. In some cases, nonpharmacologic options may be effective, although more data are needed to confirm efficacy outcomes. Comprehensive patient assessments are critical to achieve an optimal AED treatment regimen and minimize the potential for adverse effects., (Wiley Periodicals, Inc. © 2011 International League Against Epilepsy.)

One of the most intriguing recent discoveries concerning brain function is that intrinsic neuronal activity manifests as spontaneous fluctuations of the blood oxygen level-dependent (BOLD) functional MRI signal. These BOLD fluctuations exhibit temporal synchrony within widely distributed brain regions known as resting-state networks. Resting-state networks are present in the waking state, during sleep, and under general anesthesia, suggesting that spontaneous neuronal activity plays a fundamental role in brain function. Despite its ubiquitous presence, the physiological role of correlated, spontaneous neuronal activity remains poorly understood. One hypothesis is that this activity is critical for the development of synaptic connections and maintenance of synaptic homeostasis. We had a unique opportunity to test this hypothesis in a 5-y-old boy with severe epileptic encephalopathy. The child developed marked neurologic dysfunction in association with a seizure disorder, resulting in a 1-y period of behavioral regression and progressive loss of developmental milestones. His EEG showed a markedly abnormal pattern of high-amplitude, disorganized slow activity with frequent generalized and multifocal epileptiform discharges. Resting-state functional connectivity MRI showed reduced BOLD fluctuations and a pervasive lack of normal connectivity. The child underwent successful corpus callosotomy surgery for treatment of drop seizures. Postoperatively, the patient's behavior returned to baseline, and he resumed development of new skills. The waking EEG revealed a normal background, and functional connectivity MRI demonstrated restoration of functional connectivity architecture. These results provide evidence that intrinsic, coherent neuronal signaling may be essential to the development and maintenance of the brain's functional organization.

Introduction: Neuroscientists are becoming interested in the application of computational EEG analysis to the identification of ictal onset zones; however, most studies have focused on the localization of ictal onset zones in focal epilepsy. The present study aimed to estimate the ictal onset zone of Lennox-Gastaut syndrome (LGS) with bilaterally synchronous epileptiform discharges from intracranial electroencephalography (iEEG) recordings using directional connectivity analysis., Methods: We analyzed ictal iEEG data acquired from three LGS patients who underwent epileptic surgery with favorable surgical outcomes. To identify the ictal onset zones, we estimated the functional directional connectivity network among the intracerebral electrodes using the directed transfer function (DTF) method., Results: The analysis results demonstrated that areas with high average outflow values corresponded well with the surgical resection areas identified using electrophysiologic data and conventional neuroimaging modalities., Discussions: Our results suggest that the DTF analysis can be a useful auxiliary tool for determining surgical resection areas prior to epilepsy surgery in LGS patients. This is the first research article demonstrating that directional connectivity analysis of iEEG recording data can be used for delineating surgical resection areas in generalized epilepsy patients who need surgical treatment., (Copyright © 2011 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

Objective: Focal epileptogenic lesions can manifest as infantile spasms, a catastrophic type of epilepsy. Although early surgery for catastrophic epilepsies has shown positive effects, little is known regarding long-term outcomes. The present study examined long-term outcomes in patients with localization-related infantile spasms treated surgically., Methods: Data from localization-related infantile spasm cases treated surgically between 1998 and 2002 at the Asan Medical Center were retrospectively reviewed. Presurgical evaluation, surgery, postoperative seizure frequency and developmental outcome data were analyzed., Results: Five patients met the inclusion criteria, and had etiologies of tuberous sclerosis, fetal infection, encephalomalacia, malformation of cortical development and low-grade astrocytoma, respectively. The mean seizure onset age was 5.4 months (range, 3 days to 11 months), and the mean age at surgery was 19 months (range, 9-29 months). Two patients underwent a functional hemispherectomy, and the remaining three underwent lesionectomy or temporal lobectomy. The follow-up duration was 6-9 years. We found that following surgery, 4 of the 5 patients were seizure-free at the final follow-up. The 2 patients with low grade astrocytoma and cortical dysplasia, respectively showed relatively good developmental outcomes., Conclusion: Surgery may be an excellent option for treating selected patients with infantile spasms due to unilateral or focal congenital or early-acquired cortical lesions. However, developmental outcomes appear to be strongly linked to etiology and the pre-operative developmental level., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Purpose: We analyzed clinical and electroencephalography (EEG) outcomes of 13 patients with pharmacoresistant encephalopathy with electrical status epilepticus during sleep (ESES) following epilepsy surgery., Methods: All patients had symptomatic etiology of ESES and preoperative neuropsychological deterioration. Ten patients had daily atypical absences. Clinical outcome was assessed at 6 months and at 2 years after surgery. Clinical and EEG data were reviewed retrospectively. The spike propagation pattern and area and source strength in source montage were analyzed from preoperative and postoperative EEG studies., Key Findings: Preoperative sleep EEG showed electrical status epilepticus during sleep (SES) with one-way interhemispheric propagation in nine patients and with two-way interhemispheric propagation in four. The age of the patients at the time of surgery ranged from 3.6-9.9 years. Focal resection (two patients) or hemispherotomy (one patient with postoperative EEG) either terminated SES or restricted the discharge to one region. Either reduced SES propagation area or source strength was found in four of eight callosotomy patients with postoperative EEG. Of patients who had seizures preoperatively, Engel class I-II seizure outcome was observed in two of three children after focal resection or hemispherotomy and in two of eight children after callosotomy. None of these patients with Engel class I-II outcome had SES with two-way interhemispheric propagation on preoperative EEG. Cognitive deterioration was halted postoperatively in all except one patient. Cognitive catch-up of more than 10 IQ points was seen in three patients, all of whom had shown a first measured IQ of >75., Significance: Patients with pharmacoresistant ESES based on symptomatic etiology may benefit from resective surgery or corpus callosotomy regarding both seizure outcome and cognitive prognosis., (Wiley Periodicals, Inc. © 2010 International League Against Epilepsy.)