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OBJECTIVE: Identification of EEG waveforms is critical for diagnosing Lennox-Gastaut Syndrome (LGS) but is complicated by the progressive nature of the disease. Here, we assess the interrater reliability (IRR) among pediatric epileptologists for classifying EEG waveforms associated with LGS. METHODS: A novel automated algorithm was used to objectively identify epochs of EEG with transient high power, which were termed events of interest (EOIs). The algorithm was applied to EEG from 20 LGS subjects and 20 healthy controls during NREM sleep, and 1350 EOIs were identified. Three raters independently reviewed the EOIs within isolated 15-second EEG segments in a randomized, blinded fashion. For each EOI, the raters assigned a waveform label (spike and slow wave, generalized paroxysmal fast activity, seizure, spindle, vertex, muscle, artifact, nothing, or other) and indicated the perceived subject type (LGS or control). RESULTS: Labeling of subject type had 85% accuracy across all EOIs and an IRR of κ =0.790, suggesting that brief segments of EEG containing high-power waveforms can be reliably classified as pathological or normal. Waveform labels were less consistent, with κ =0.558, and the results were highly variable for different categories of waveforms. Label mismatches typically occurred when one reviewer selected nothing, suggesting that reviewers had different thresholds for applying named labels. SIGNIFICANCE: Classification of EEG waveforms associated with LGS has weak IRR, due in part to varying thresholds applied during visual review. Computational methods to objectively define EEG biomarkers of LGS may improve IRR and aid clinical decision-making.

Lennox Gastaut syndrome (LGS) as an electroclinical diagnosis has been utilized as a clinical entity for more than 70 years. However, with the recognition of other distinct electroclinical epilepsy syndromes, no consistent single etiology, and the variability of criteria used in clinical trials, the clinical utility of such a diagnosis has been questioned. Recently, the International League Against Epilepsy for the first time defined diagnostic criteria for epilepsy syndromes, thereby allowing consistent language and inclusion criteria to be utilized. Recent diagnostic criteria for syndrome diagnosis are explored as defined by the International League Against Epilepsy, with further literature reviewed to highlight relevant features, and differential diagnosis explored. Developmental and Epileptic Encephalopathy (DEE) is an overall term that may be descriptive of many different epilepsies, most of early onset, whether electroclinically or etiologically defined, of which LGS is one. Although we have moved forward in defining an increasing number of etiologically specific syndromes, this to date remains a minority of the DEEs. Although there is progress with precision medicine targeted at specific causes, the term LGS still remains useful as a diagnosis in defining treatment options, as well as overall prognosis. [ABSTRACT FROM AUTHOR]

Lennox Gastaut Syndrome (LGS) is characterized by drug-resistant epilepsy that typically leads to decreased quality of life and deleterious neurodevelopmental comorbidities from medically refractory seizures. In recent years there has been a dramatic increase in the development and availability of novel treatment strategies for Lennox Gastaut Syndrome patient to improve seizure. Recent advances in neuromodulation and minimally invasive magnetic resonance guided laser interstitial thermal therapy (MRgLITT) have paved the way for new treatments strategies including deep brain stimulation (DBS), responsive neurostimulation (RNS), and MRgLITT corpus callosum ablation. These new strategies offer hope for children with drug-resistant generalized epilepsies, but important questions remain about the safety and effectiveness of these new approaches. In this review, we describe the opportunities presented by these new strategies and how each treatment strategy is currently being employed. Next, we will critically assess available evidence for these new approaches compared to traditional palliative epilepsy surgery approaches, such as vagus nerve stimulation (VNS) and open microsurgical corpus callosotomy (CC). Finally, we will describe future directions that would help define which of the available strategies should be employed and when. [ABSTRACT FROM AUTHOR]

Purpose This study examined the characteristics and outcomes of resective epilepsy surgery following corpus callosotomy (CC) in children with Lennox-Gastaut syndrome (LGS). Methods We retrospectively analyzed 17 children with LGS who underwent resective surgery (RS) after CC over a span of 10 years, with a minimum of 2 years of follow-up, at a single tertiary epilepsy center in Korea. Results Of the 17 patients, 13 (73.5%) demonstrated favorable surgical outcomes (Engel class I or II) at 1 year after RS, and eight (47.1%) were ultimately free of seizures 2 years after surgery. A significantly larger decrease in the number of anti-seizure medications taken from before to 2 years after the final surgical procedure was observed in the group that became seizure-free than in the group with persistent seizures (P=0.062). Furthermore, a significantly greater decline in daily adaptive function was found in the persistent seizure group (P=0.059). The baseline characteristics, results of presurgical evaluation, and treatment-related factors assessed prior to surgery showed no significant differences between the seizure-free group and the group with persistent seizures. Conclusion In conclusion, RS may be a viable option for patients with LGS who exhibit lateralization and/or localization on presurgical evaluation after CC, as the procedure may reveal a concealed primary focus. The proactive implementation of two-stage epilepsy surgery could provide significant seizure reduction and preservation of cognitive function in carefully selected patients with LGS.

Purpose: This study examined the characteristics and outcomes of resective epilepsy surgery following corpus callosotomy (CC) in children with Lennox-Gastaut syndrome (LGS). Methods: We retrospectively analyzed 17 children with LGS who underwent resective surgery (RS) after CC over a span of 10 years, with a minimum of 2 years of follow-up, at a single tertiary epilepsy center in Korea. Results: Of the 17 patients, 13 (73.5%) demonstrated favorable surgical outcomes (Engel class I or II) at 1 year after RS, and eight (47.1%) were ultimately free of seizures 2 years after surgery. A significantly larger decrease in the number of anti-seizure medications taken from before to 2 years after the final surgical procedure was observed in the group that became seizure-free than in the group with persistent seizures (P=0.062). Furthermore, a significantly greater decline in daily adaptive function was found in the persistent seizure group (P=0.059). The baseline characteristics, results of presurgical evaluation, and treatment-related factors assessed prior to surgery showed no significant differences between the seizure-free group and the group with persistent seizures. Conclusion: In conclusion, RS may be a viable option for patients with LGS who exhibit lateralization and/or localization on presurgical evaluation after CC, as the procedure may reveal a concealed primary focus. The proactive implementation of two-stage epilepsy surgery could provide significant seizure reduction and preservation of cognitive function in carefully selected patients with LGS. [ABSTRACT FROM AUTHOR]

Lennox Gastaut Syndrome (LGS) is characterized by drug-resistant epilepsy that typically leads to decreased quality of life and deleterious neurodevelopmental comorbidities from medically refractory seizures. In recent years there has been a dramatic increase in the development and availability of novel treatment strategies for Lennox Gastaut Syndrome patient to improve seizure. Recent advances in neuromodulation and minimally invasive magnetic resonance guided laser interstitial thermal therapy (MRgLITT) have paved the way for new treatments strategies including deep brain stimulation (DBS), responsive neurostimulation (RNS), and MRgLITT corpus callosum ablation. These new strategies offer hope for children with drug-resistant generalized epilepsies, but important questions remain about the safety and effectiveness of these new approaches. In this review, we describe the opportunities presented by these new strategies and how each treatment strategy is currently being employed. Next, we will critically assess available evidence for these new approaches compared to traditional palliative epilepsy surgery approaches, such as vagus nerve stimulation (VNS) and open microsurgical corpus callosotomy (CC). Finally, we will describe future directions that would help define which of the available strategies should be employed and when.

Purpose Lamotrigine (LTG) is often used as adjunctive therapy in Lennox-Gastaut syndrome (LGS); however, it may worsen myoclonic and atypical absence seizures in LGS patients. This study reviewed the overall efficacy and safety of LTG in children with LGS. Methods This retrospective study included 38 patients (aged 50% in 47.4% of patients (18/38). After 6 months, 20 patients (20/36, 55.6%) showed a favorable response. After 12 months, five patients (5/11, 45.5%) responded to treatment. Three patients showed myoclonic seizures at the start of treatment and >50% amelioration in seizure frequency at the 3- and 6-month follow-up visits. Conclusion This study reaffirms the efficacy and safety of LTG in children with LGS. Therefore, LTG is strongly recommended as an adjunctive therapy for children with LGS.

Purpose This study evaluated the efficacy and tolerability of cannabidiol (CBD) as an add-on therapy for childhood-onset Lennox-Gastaut syndrome (LGS). Methods This retrospective study enrolled patients who visited the Department of Pediatric Neurology at Asan Medical Center from March 2019 to February 2022 and were treated with CBD. Electronic medical records and clinically relevant factors (including the type of epilepsy and seizures, etiology, and the number of concomitantly used anti-epileptic drugs) were reviewed. The outcome was clinical response to CBD (≥50% or 3 years) was associated with a favorable response to CBD treatment. Further prospective studies with larger populations are needed to evaluate the tolerability and efficacy of CBD in patients with drug-resistant epilepsy of various etiologies.

Purpose: Lamotrigine (LTG) is often used as adjunctive therapy in Lennox-Gastaut syndrome (LGS); however, it may worsen myoclonic and atypical absence seizures in LGS patients. This study reviewed the overall efficacy and safety of LTG in children with LGS. Methods: This retrospective study included 38 patients (aged <18 years) with LGS who underwent LTG adjunctive therapy between October 2020 and March 2022 at Severance Children's Hospital. The primary outcome was the change in seizure frequency at 3, 6, and 12 months after starting LTG treatment. A favorable treatment response was defined as a ≥50% reduction in seizure frequency. Results: The main seizure semiology at the start of treatment was tonic-clonic in 15 (39.5%) patients, spasm in 14 (36.8%), atonic in five (13.2%), myoclonic in three (7.9%), and absence in one (2.6%). The median number of anti-seizure medications (ASMs) was 3.95 (interquartile range, 3 to 4.75). The most common concomitant ASMs were valproate (35/38, 92.1%), levetiracetam (23/38, 60.5%), and topiramate (20/38, 52.6%). After 3 months, seizure frequency was reduced by >50% in 47.4% of patients (18/38). After 6 months, 20 patients (20/36, 55.6%) showed a favorable response. After 12 months, five patients (5/11, 45.5%) responded to treatment. Three patients showed myoclonic seizures at the start of treatment and >50% amelioration in seizure frequency at the 3- and 6-month follow-up visits. Conclusion: This study reaffirms the efficacy and safety of LTG in children with LGS. Therefore, LTG is strongly recommended as an adjunctive therapy for children with LGS. [ABSTRACT FROM AUTHOR]

Background: Cannabis is the most widely used illicit substance worldwide, and legalization for recreational and medical purposes has substantially increased its availability and use in the United States.Objectives: Decades of research have suggested that recreational cannabis use confers risk for cognitive impairment across various domains, and structural and functional differences in the brain have been linked to early and heavy cannabis use.Methods: With substantial evidence for the role of the endocannabinoid system in neural development and understanding that brain development continues into early adulthood, the rising use of cannabis in adolescents and young adults raises major concerns. Yet some formulations of cannabinoid compounds are FDA-approved for medical uses, including applications in children.Results: Potential effects on the trajectory of brain morphology and cognition, therefore, should be considered. The goal of this review is to update and consolidate relevant findings in order to inform attitudes and public policy regarding the recreational and medical use of cannabis and cannabinoid compounds.Conclusions: The findings point to considerations for age limits and guidelines for use.

Purpose This study presents the characteristics of patients with mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE) with SLC35A2 somatic variants in the brain who underwent epilepsy surgery and showed clinical improvement in seizures. Methods We collected 10 patients with SLC35A2 somatic mutations in the brain who underwent surgery to treat drug-resistant epilepsy at Severance Children’s Hospital from 2014 to 2019 and retrospectively reviewed their genetic profiles, neuropathologic results, clinical features, pre-operative evaluations, and post-operative outcomes. Results Six of the 10 patients with SCL35A2 somatic mutations in the brain had Lennox Gastaut syndrome (LGS) evolving from infantile spasms (IS), three had LGS, and one had IS. The median value of variant allele frequencies (VAFs) was 5.7% (1.7% to 5.8%; range, 1.4% to 22.9%). Nonsense mutations were the most common (50%), followed by missense mutations (40%) and a splicing site mutation (10%). Eight patients (80%) had good post-operative outcomes, with freedom from disabling seizures in five (Engel class I) and rare disabling seizures in three (Engel class II). Four of the eight patients who could be assessed for social quotient (SQ) after surgery showed SQ improvements by 12.2±6.4. Although all patients were finally diagnosed with MOGHE, seven (70%) were initially diagnosed with gliosis, two with mild malformation of cortical development, and one with no abnormality. Conclusion All patients with SCL35A2 brain somatic mutations, even with low VAFs, had refractory epilepsy such as LGS or IS, and were finally diagnosed with MOGHE. This report is the first in Korea to our knowledge.