A systematic literature review on the global epidemiology of Dravet syndrome and Lennox-Gastaut syndrome: Prevalence, incidence, diagnosis, and mortality.

Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS) are rare developmental and epileptic encephalopathies associated with seizure and nonseizure symptoms. A comprehensive understanding of how many individuals are affected globally, the diagnostic journey they face, and the extent of mortality associated with these conditions is lacking. Here, we summarize and evaluate published data on the epidemiology of DS and LGS in terms of prevalence, incidence, diagnosis, genetic mutations, and mortality and sudden unexpected death in epilepsy (SUDEP) rates. The full study protocol is registered on PROSPERO (CRD42022316930). After screening 2172 deduplicated records, 91 unique records were included; 67 provided data on DS only, 17 provided data on LGS only, and seven provided data on both. Case definitions varied considerably across studies, particularly for LGS. Incidence and prevalence estimates per 100 000 individuals were generally higher for LGS than for DS (LGS: incidence proportion = 14.5-28, prevalence = 5.8-60.8; DS: incidence proportion = 2.2-6.5, prevalence = 1.2-6.5). Diagnostic delay was frequently reported for LGS, with a wider age range at diagnosis reported than for DS (DS, 1.6-9.2 years; LGS, 2-15 years). Genetic screening data were reported by 63 studies; all screened for SCN1A variants, and only one study specifically focused on individuals with LGS. Individuals with DS had a higher mortality estimate per 1000 person-years than individuals with LGS (DS, 15.84; LGS, 6.12) and a lower median age at death. SUDEP was the most frequently reported cause of death for individuals with DS. Only four studies reported mortality information for LGS, none of which included SUDEP. This systematic review highlights the paucity of epidemiological data available for DS and especially LGS, demonstrating the need for further research and adoption of standardized diagnostic criteria.

Epidemiology of Developmental and Epileptic Encephalopathy and of Intellectual Disability and Epilepsy in Children.

BACKGROUND AND OBJECTIVES: We aimed to determine the population-based cumulative incidence and prevalence of developmental and epileptic encephalopathies (DEEs) and intellectual disability and epilepsy (ID+E) in children. We analyzed the cumulative incidence of specific epilepsy syndromes. METHODS: Children younger than 16 years with a DEE or ID+E were ascertained using EEG records from 2000 to 2016 in the Wellington region of New Zealand. Epilepsy syndromes were diagnosed on medical record and EEG review. Point prevalence and cumulative incidence for children with epilepsy and developmental impairment, DEE and ID+E were calculated. Cumulative incidence for each epilepsy syndrome was calculated. RESULTS: The cohort comprised 235 children (58% male) with developmental impairment and epilepsy, including 152 (65%) with DEE and 83 (35%) with ID+E. The median age of seizure onset was 15.4 months (range day 1-15 years). The median follow-up from seizure onset was 7.9 years (range 0-18.2 years). Point prevalence for the broad group of children with epilepsy and developmental impairment was 175/100,000 children (95% CI 149-203; DEE 112 and ID+E 63/100,000 children). Cumulative incidence for DEE was 169/100,000 children (95% CI 144-199) and that for ID+E was 125/100,000 children (95% CI 95.4-165). Cumulative incidence per 100,000 children was as follows: infantile epileptic spasms syndrome 58.2 (95% CI 45.0-75.3), epilepsy with myoclonic-atonic seizures 16.4 (95% CI 9.69-27.7), Lennox-Gastaut syndrome 13.2 (95% CI 4.1-41.9), and Dravet syndrome 5.1 (95% CI 2.1-12.2). Fifty/152 (33%) of children with DEE and 70/83 (84%) with ID+E could not be diagnosed with a known epilepsy syndrome. DISCUSSION: Epilepsy and developmental impairment before the age of 16 years occurs in 1 in 340 children, with 1 in 590 having a DEE and 1 in 800 having ID+E. These individuals require significant health and community resources; therefore, these data will inform complex health service and education planning. Epidemiologic studies have focused on early childhood-onset DEEs. These do not fully reflect the burden of these disorders because 27% of DEEs and 70% of ID+E begin later, with seizure onset after the age of 3 years. Understanding the cumulative incidence of specific syndromes together with the broad group of DEEs is essential for the planning of therapeutic trials. Given trials focus on specific syndromes, there is a risk that effective therapies will not be developed for one-third of children with DEE.

Age at onset in patients with Lennox-Gastaut syndrome: Correlations with clinical manifestations.

The aim of the current study was to investigate the age at onset in patients with Lennox-Gastaut Syndrome (LGS). We also investigated the clinical and EEG characteristics of these patients in different age groups. This was a retrospective study. All patients with a diagnosis of LGS were recruited at the outpatient epilepsy clinic at Shiraz University of Medical Sciences, Shiraz, Iran, from 2008 through 2020. 300 patients had LGS. Age at onset was 3.3 ± 4.1 years (minimum = 0 and maximum = 21 years). In 10 patients (3%) LGS started at age 14 years or above. Epileptic spasms were more often observed in those with an age at onset below one year (8%) compared with those with an age at onset of 1 to 8 years (0.7%) [Odds Ratio (OR) = 10.32]. Intellectual disability was less frequently observed in those with an age at onset of 8 years and above (68%) compared with those with an age at onset of 1 to 8 years (90%) (OR = 0.33). Tonic-clonic seizures were more often observed in those with an age at onset of 8 years and above (83%) compared with those with an age at onset of 1 to 8 years (55%) (OR = 2.87). While age at onset of LGS in the majority of patients is below 8 years, in some patients the syndrome begins in their late childhood or even during adolescence. Age at onset of LGS has significant correlations with the clinical manifestations of the syndrome.

Assessing seizure burden in pediatric epilepsy using an electronic medical record-based tool through a common data element approach.

OBJECTIVE: Improvement in epilepsy care requires standardized methods to assess disease severity. We report the results of implementing common data elements (CDEs) to document epilepsy history data in the electronic medical record (EMR) after 12 months of clinical use in outpatient encounters. METHODS: Data regarding seizure frequency were collected during routine clinical encounters using a CDE-based form within our EMR. We extracted CDE data from the EMR and developed measurements for seizure severity and seizure improvement scores. Seizure burden and improvement was evaluated by patient demographic and encounter variables for in-person and telemedicine encounters. RESULTS: We assessed a total of 1696 encounters in 1038 individuals with childhood epilepsies between September 6, 2019 and September 11, 2020 contributed by 32 distinct providers. Childhood absence epilepsy (n = 121), Lennox-Gastaut syndrome (n = 86), and Dravet syndrome (n = 42) were the most common epilepsy syndromes. Overall, 43% (737/1696) of individuals had at least monthly seizures, 17% (296/1696) had a least daily seizures, and 18% (311/1696) were seizure-free for >12 months. Quantification of absolute seizure burden and changes in seizure burden over time differed between epilepsy syndromes, including high and persistent seizure burden in patients with Lennox-Gastaut syndrome. Individuals seen via telemedicine or in-person encounters had comparable seizure frequencies. Individuals identifying as Hispanic/Latino, particularly from postal codes with lower median household incomes, were more likely to have ongoing seizures that worsened over time. SIGNIFICANCE: Standardized documentation of clinical data in childhood epilepsies through CDE can be implemented in routine clinical care at scale and enables assessment of disease burden, including characterization of seizure burden over time. Our data provide insights into heterogeneous patterns of seizure control in common pediatric epilepsy syndromes and will inform future initiatives focusing on patient-centered outcomes in childhood epilepsies, including the impact of telemedicine and health care disparities.

The severe epilepsy syndromes of infancy: A population-based study.

OBJECTIVE: To study the epilepsy syndromes among the severe epilepsies of infancy and assess their incidence, etiologies, and outcomes. METHODS: A population-based cohort study was undertaken of severe epilepsies with onset before age 18 months in Victoria, Australia. Two epileptologists reviewed clinical features, seizure videos, and electroencephalograms to diagnose International League Against Epilepsy epilepsy syndromes. Incidence, etiologies, and outcomes at age 2 years were determined. RESULTS: Seventy-three of 114 (64%) infants fulfilled diagnostic criteria for epilepsy syndromes at presentation, and 16 (14%) had "variants" of epilepsy syndromes in which there was one missing or different feature, or where all classical features had not yet emerged. West syndrome (WS) and "WS-like" epilepsy (infantile spasms without hypsarrhythmia or modified hypsarrhythmia) were the most common syndromes, with a combined incidence of 32.7/100 000 live births/year. The incidence of epilepsy of infancy with migrating focal seizures (EIMFS) was 4.5/100 000 and of early infantile epileptic encephalopathy (EIEE) was 3.6/100 000. Structural etiologies were common in "WS-like" epilepsy (100%), unifocal epilepsy (83%), and WS (39%), whereas single gene disorders predominated in EIMFS, EIEE, and Dravet syndrome. Eighteen (16%) infants died before age 2 years. Development was delayed or borderline in 85 of 96 (89%) survivors, being severe-profound in 40 of 96 (42%). All infants with EIEE or EIMFS had severe-profound delay or were deceased, but only 19 of 64 (30%) infants with WS, "WS-like," or "unifocal epilepsy" had severe-profound delay, and only two of 64 (3%) were deceased. SIGNIFICANCE: Three quarters of severe epilepsies of infancy could be assigned an epilepsy syndrome or "variant syndrome" at presentation. In this era of genomic testing and advanced brain imaging, diagnosing epilepsy syndromes at presentation remains clinically useful for guiding etiologic investigation, initial treatment, and prognostication.

Hypercalcemia in Children Using the Ketogenic Diet: A Multicenter Study.

CONTEXT: The ketogenic diet is associated with progressive skeletal demineralization, hypercalciuria, and nephrolithiasis. Acute hypercalcemia has been described as a newly recognized complication of this treatment. OBJECTIVE: To describe the clinical characteristics of acute hypercalcemia in children on the ketogenic diet through analysis of the presentation, response to treatment, and natural history in a large cohort of patients. DESIGN: A multicenter case series was performed including children who developed acute hypercalcemia while treated with the ketogenic diet. Information on clinical presentation, treatment, and course of this complication was collated centrally. RESULTS: There were 14 patients (median (range) age 6.3 (0.9 to 18) years) who developed hypercalcemia 2.1 (range, 0.2-12) years after starting the ketogenic diet. All had low levels of parathyroid hormone and levels of 1,25-dihydroxyvitamin D were low in all except one. Seven (50%) had impaired renal function at presentation. All except the 2 oldest had low alkaline phosphatase levels for age. Once normocalcemia was achieved, hypercalcemia recurred in only 2 of these patients over observation of up to 9.8 years. One patient discontinued the ketogenic diet prior to achieving normocalcemia while 4 more stopped the diet during follow-up after resolution of hypercalcemia. CONCLUSIONS: Ketotic hypercalcemia can occur years after starting the ketogenic diet, especially in the setting of renal impairment. The mechanism is unknown but appears to be due to reduced osteoblast activity and impaired bone formation. We recommend close attention to optimizing bone health in these children, and screening for the development of ketotic hypercalcemia.

Lennox-Gastaut syndrome: New treatments and treatments under investigation.

There are currently five compounds (clobazam, felbamate, lamotrigine, topiramate, rufinamide) available for prescription with a demonstrated efficacy on drop seizures for Lennox-Gastaut syndrome (LGS). There are also currently new and under-investigation compounds. This paper gives an overview on these novel developments for LGS based on the lecture given at the French Chapter meeting of the International League Against Epilepsy (ILAE) held in Paris in October 2019. Five compounds were discussed. Epidiolex (cannabidiol) has been approved recently based on positive randomized control trials in LGS patients. Four drugs are under investigation according to a search on the 'clinicaltrials.gov' database. Perampanel and fenfluramine are both being studied in ongoing phase 3 studies. Two compounds are in an earlier stage of development with ongoing phase 1 and 2 studies: carisbamate and OV953. We summarized the publicly available data. Based on these drug development programs, we can expect that new compounds will become available for LGS in the next years, possibly resulting in new treatment paradigms.

The refractory epilepsy screening tool for Lennox-Gastaut syndrome (REST-LGS).

BACKGROUND: The complex clinical presentation and progression of Lennox-Gastaut syndrome (LGS) can complicate the accurate diagnosis of this severe, lifelong, childhood-onset epilepsy, often resulting in suboptimal treatment. The Refractory Epilepsy Screening Tool for LGS (REST-LGS) was developed to improve the identification of patients with LGS. METHODS: Using the Modified Delphi Consensus, a group of experts developed and tested the REST-LGS Case Report Form (CRF) comprising 8 criteria (4 major, 4 minor) considered potentially indicative of LGS. Diagnosis-blinded specialist and nonspecialist raters at 2 epilepsy centers applied the CRF to deidentified patient records, including 1:1 records of patients with drug-resistant epilepsy or confirmed LGS. Interrater reliability was measured by Cohen's κ. Diagnosis was then unblinded to reveal common criteria for LGS or drug-resistant epilepsy. Cronbach's α was used to measure internal consistency between raters for all criteria combined. RESULTS: Of 200 patients, 81% to 85% met 1 to 3 major criteria. At both sites, moderate (κ, 0.41-0.60) to good (κ, 0.61-0.80) agreement on most criteria was reached between expert and nonexpert raters. Unblinding revealed that most patients with LGS met 3 major and 2 to 3 minor criteria, while patients with drug-resistant epilepsy met ≤1 major and only 1 to 2 minor criteria. Cronbach's α of raters at both sites was 0.64. CONCLUSIONS: The combined number of major/minor criteria on the CRF may be particularly indicative of LGS. Therefore, the REST-LGS may be a valuable clinical tool in identifying patients requiring further diagnostic evaluation for LGS.

Evolution and course of early life developmental encephalopathic epilepsies: Focus on Lennox-Gastaut syndrome.

OBJECTIVES: Developmental encephalopathic epilepsies (DEEs) are characterized by refractory seizures, disability, and early death. Opportunities to improve care and outcomes focus on West syndrome/infantile spasms (WS/IS). Lennox-Gastaut syndrome (LGS) is almost as common but receives little attention. We examined initial presentations of DEEs and their evolution over time to identify risk and indicators of developing LGS. METHODS: Data are from the Connecticut Study of Epilepsy, a prospective, longitudinal study of 613 children with newly diagnosed epilepsy recruited in 1993-1997. Central review of medical records permitted classification of epilepsy syndromes at diagnosis and at reclassification 2, 5, and 9 years later. DEEs were compared to other epilepsies for seizure and cognitive outcomes and mortality. Analyses examined the evolution of DEE syndromes after initial presentation, with specific comparisons made between WS/IS and LGS. Statistical analyses were performed with t tests and chi-square tests. RESULTS: Fifty-eight children (9.4%) had DEEs, median onset age = 1.1 years (interquartile range ([IQR] 0.3-1.3) in DEEs and 6.0 years (IQR 3.0-9.0) in other epilepsies (P < 0.001). DEEs vs other epilepsies had more pharmacoresistance (71% vs 18%), intellectual disability (84% vs 11%), and mortality (21% vs <1%; all P < 0.001). During follow-up, the form of epilepsy evolved in 33 children. WS/IS was the most common initial diagnosis (N = 23) and in 5 children WS/IS evolved later. LGS was diagnosed initially in 4 children (1 later revised) and in 22 by the end of follow-up, including 7 evolving from WS/IS and 12 from nonsyndromic generalized, focal, or undetermined epilepsies. Evolution to LGS took a median of 1.9 years. LGS developed in 13% of infants, including 9% of those who did not present initially with WS/IS. SIGNIFICANCE: DEEs account for disproportionate amounts of pharmacoresistance, disability, and early mortality. LGS often has a window between initial presentation and full expression. LGS should become targeted for early detection and prevention.

Few individuals with Lennox-Gastaut syndrome have autism spectrum disorder: a comparison with Dravet syndrome.

BACKGROUND: Autism spectrum disorder (ASD) in epilepsy has been a topic of increasing interest, which in general occurs in 15-35% of the patients with epilepsy, more frequently in those with intellectual disability (ID). Lennox-Gastaut syndrome (LGS) and Dravet syndrome (DS) are two typical forms of intractable epileptic encephalopathy associated with ID. We previously reported that ASD was diagnosed in 24.3% of patients with DS, higher in those with profound ID. Given the severe epilepsy and high frequency of ID in LGS, it is necessary to know whether ASD is a common psychomotor co-morbidity of LGS. This study evaluated the autistic behaviors and intelligence in patients with LGS and further compared that between LGS and DS, aiming to understand the complex pathogenesis of epilepsy-ASD-ID triad. METHODS: A total of 50 patients with LGS and 45 patients with DS were enrolled and followed up for at least 3 years. The clinical characteristics were analyzed, and evaluations of ASD and ID were performed. RESULTS: No patients with LGS fully met the diagnostic criteria for ASD, but three of them exhibited more or less autistic behaviors. Majority (86%) of LGS patients presented ID, among which moderate to severe ID was the most common. Early onset age and symptomatic etiology were risk predictors for ID. The prevalence of ASD in LGS was significantly lower than that in DS (0/50 vs. 10/45, p < 0.001), while the prevalence and severity of ID showed no significant difference between the two forms of epileptic encephalopathy. CONCLUSIONS: This study demonstrated a significant difference in the co-morbidity of ASD between LGS and DS, although they had a similar prevalence and severity of ID, refuting the proposal that the prevalence of ASD in epilepsy is accounted for by ID. These findings suggest that the co-morbidity of ASD, ID, and epilepsy may result from multifaceted pathogenic mechanisms.

Lennox-Gastaut syndrome: a comprehensive review.

Lennox-Gastaut syndrome (LGS) is considered an epileptic encephalopathy and is defined by a triad of multiple drug-resistant seizure types, a specific EEG pattern showing bursts of slow spike-wave complexes or generalized paroxysmal fast activity, and intellectual disability. The prevalence of LGS is estimated between 1 and 2% of all patients with epilepsy. The etiology of LGS is often divided into two groups: identifiable (genetic-structural-metabolic) in 65 to 75% of the patients and LGS of unknown cause in others. Lennox-Gastaut syndrome may be considered as secondary network epilepsy. The seizures in LGS are usually drug-resistant, and complete seizure control with resolution of intellectual and psychosocial dysfunction is often not achievable. Reduction in frequency of the most incapacitating seizures (e.g., drop attacks and tonic-clonic seizures) should be the major objective. Valproate, lamotrigine, and topiramate are considered to be the first-line drugs by many experts. Other effective antiepileptic drugs include levetiracetam, clobazam, rufinamide, and zonisamide. The ketogenic diet is an effective and well-tolerated treatment option. For patients with drug resistance, a further therapeutic option is surgical intervention. Corpus callosotomy is a palliative surgical procedure that aims at controlling the most injurious seizures. Finally, vagus nerve stimulation offers reasonable seizure improvement. The long-term outcome for patients with LGS is generally poor. This syndrome is often associated with long-term adverse effects on intellectual development, social functioning, and independent living.

The epilepsy phenotype in adult patients with intellectual disability and pathogenic copy number variants.

PURPOSE: To characterize the electroclinical features of epilepsy associated with intellectual disability and pathogenic copy number variations (CNVs) METHODS: we prospectively investigated 61 adult patients with epilepsy and intellectual disability or other neurodevelopmental disorders. We performed high resolution SNP-Array analysis in order to detect clinical relevant chromosomal microdeletions and microduplications. An ordinal logistic regression model was fitted with 34 demographic, clinical and EEG-related variables in order to identify the epilepsy phenotype of patients with pathogenic CNVs. RESULTS: chromosome microarray analysis identify non-polymorphic CNVs in 33 patients analyzed: 11 had an established pathogenic microdeletion/microduplication, 22 were carriers of CNVs of unknown clinical significance. Univariate analysis revealed a significant association between pathogenic CNVs and 3 electroclinical variables considered, specifically atypical absence seizures (p<0.05), tonic seizures (p<0.05), epileptic spasms (p<0.01). CONCLUSIONS: high resolution SNP-Array analysis should be evaluated in adult patients with intellectual disability and epilepsy with peculiar electroclinical features, specifically atypical absence seizures, tonic seizures, and epileptic spasms, resembling a Lennox-Gastaut syndrome without a clear structural lesion.

Use of perampanel in children and adolescents with Lennox-Gastaut Syndrome.

AIM: Report the use of perampanel treatment in children with Lennox-Gastaut syndrome (LGS). METHOD: We conducted a prospective study of 13 LGS patients (seven male; mean age, 12.8years) treated with adjunctive perampanel therapy. Perampanel was initiated at 2mg/day and titrated to a median maximum dose of 6mg/day. RESULTS: After a mean follow-up duration of 10.8months (range, 1-24months), nine patients (69.2%) were responders (≥50% reduction in total seizure frequency) and nine (69.2%) were rated by their physician as "much improved" or "very much improved". Four patients (30.8%) discontinued perampanel due to the lack of efficacy (n=2) and seizure aggravation (n=2). No patients discontinued due to other adverse events (AEs). AEs were reported for six patients (46.2%) and comprised decreased activity/social interaction (n=3), behavior disturbance with agitation (n=2), and/or fatigue (n=2). All AEs became manageable after perampanel dosing was decreased. Improvements in cognitive function and/or behavior were reported for seven patients (53.8%). Introduction of perampanel allowed the dose reduction and/or discontinuation of other treatments in seven patients (53.8%). INTERPRETATION: Perampanel was efficacious and generally well tolerated as an adjunctive treatment for seizures associated with LGS, supporting further research in this area.

Assessment of treatment patterns and healthcare costs associated with probable Lennox-Gastaut syndrome.

Lennox-Gastaut syndrome (LGS) is a chronic and severe form of epilepsy characterized by intractable seizures, cognitive impairment, and abnormal electroencephalogram findings with slow spike-wave complexes. It typically presents before age 8, but symptoms continue into adulthood and require lifelong treatment associated with significant clinical burden. Data on LGS-associated healthcare utilization and costs are limited. In this study we use a claims-based LGS classifier based on random forest methodology to identify patients with probable LGS from the a Medicaid multi-state database and assess its prevalence across the age spectrum, healthcare utilization, treatment patterns, costs, and comorbid conditions. The classifier identified patients with probable LGS across all ages, with up to 8% of 10-year-old patients with epilepsy identified as having probable LGS. The prevalence of probable LGS was lower in older age cohorts, indicating that it may be under-recognized in older patients. Our analysis showed that probable LGS is associated with considerably higher total healthcare and medical costs than non-LGS patients. The costs were generally consistent between age cohorts, suggesting that the cost burden extends beyond childhood and has a lifelong impact. Analysis of treatment patterns suggest that while the majority of probable LGS patients in this study received widest-spectrum AEDs, a considerable proportion did not and therefore may have been inadequately treated. Further, usage of clobazam and rufinamide was decreased in older compared to younger patient cohorts, indicating that older patient cohorts are less likely to be receiving optimum treatment for LGS. These findings indicate the need for increased clinical attention to LGS beyond pediatric years, with a focus on optimization of treatment for LGS patients of all ages with widest-spectrum AEDs. Timely recognition and adequate treatment of LGS are likely to result in improved outcomes and less costly management of this condition.

Familial aggregation of focal seizure semiology in the Epilepsy Phenome/Genome Project.

OBJECTIVE: To improve phenotype definition in genetic studies of epilepsy, we assessed the familial aggregation of focal seizure types and of specific seizure symptoms within the focal epilepsies in families from the Epilepsy Phenome/Genome Project. METHODS: We studied 302 individuals with nonacquired focal epilepsy from 149 families. Familial aggregation was assessed by logistic regression analysis of relatives' traits (dependent variable) by probands' traits (independent variable), estimating the odds ratio for each symptom in a relative given presence vs absence of the symptom in the proband. RESULTS: In families containing multiple individuals with nonacquired focal epilepsy, we found significant evidence for familial aggregation of ictal motor, autonomic, psychic, and aphasic symptoms. Within these categories, ictal whole body posturing, diaphoresis, dyspnea, fear/anxiety, and déjà vu/jamais vu showed significant familial aggregation. Focal seizure type aggregated as well, including complex partial, simple partial, and secondarily generalized tonic-clonic seizures. CONCLUSION: Our results provide insight into genotype-phenotype correlation in the nonacquired focal epilepsies and a framework for identifying subgroups of patients likely to share susceptibility genes.

Lennox-Gastaut Syndrome: A State of the Art Review.

Lennox-Gastaut syndrome (LGS) is a severe age-dependent epileptic encephalopathy usually with onset between 1 and 8 years of age. Functional neuroimaging studies recently introduced the concept of Lennox-Gastaut as "secondary network epilepsy" resulting from dysfunctions of a complex system involving both cortical and subcortical structures (default-mode network, corticoreticular connections, and thalamus). These dysfunctions are produced by different disorders including hypoxic-ischemic encephalopathies, meningoencephalitis, cortical malformations, neurocutaneous disorders, or tumors. The list of etiologies was expanded to pathogenic copy number variants at whole-genome array comparative genomic hybridization associated with late-onset cases or pathogenic mutations involving genes, such as GABRB3, ALG13, SCN8A, STXBP1, DNM1, FOXG1, or CHD2. Various clinical trials demonstrated the usefulness of different drugs (including rufinamide, clobazam, lamotrigine, topiramate, or felbamate), ketogenic diet, resective surgery, corpus callosotomy, and vagus nerve stimulation in the treatment of epileptic manifestations. The outcome of LGS often remains disappointing regarding seizure control or cognitive functioning. The realization of animal models, which are still lacking, and the full comprehension of molecular mechanisms involved in epileptogenesis and cognitive impairment would give a relevant support to further improvements in therapeutic strategies for LGS patients.

Vagus Nerve Stimulation for Epilepsy: An Evidence-Based Approach.

Medical treatment of seizures yields a satisfactory response in 75-80% of the patients; resective epilepsy surgery is a therapeutic option for those patients who are refractory to drug therapy, but there is still a considerable portion (20-30%) of patients who are ineligible for surgery or failed surgery. Vagus nerve stimulation (VNS) might be an option for these very refractory patients. We carried out an evidence-based search to identify the best evidence presently available related to the use of VNS. We used multiple searchable databases (primary: PubMed-MEDLINE, EMBASE, LILACS, and SciELO; secondary: Cochrane Library) and a standard structured approach know as the PICO scheme: P (patient), I (intervention), C (comparison), and O (outcome). Publications were selected based on study design, PICO components, language, and availability of full text. For study design, we included papers designed as 'randomized controlled trials'; these trials were evaluated according to the Jadad score; the type II error was not used while selecting studies to avoid further limitations. Twenty-eight papers were selected, all from PubMed-MEDLINE. The search results showed that patients older than 12 years with refractory partial seizures (with or without generalization) may benefit from VNS. Children might also benefit, but might need different stimulation parameters. We also noted that higher stimulation settings are associated with increased occurrence of hoarseness, throat pain, cough, and dyspnea. The available randomized controlled trials and cohorts made it clear that VNS is a useful palliative procedure in adult patients with partial epilepsy, and a 50-60% reduction in seizure frequency might be expected in at least 50% of the patients. VNS is a useful palliative procedure in patients with refractory epilepsy. As our practical experience and understanding of the mechanism of action of VNS increase, more homogeneous patient populations that might respond better to VNS are being recognized, such as children with secondary generalized epilepsy and some types of reflex epilepsy.

Independent Neuronal Origin of Seizures and Behavioral Comorbidities in an Animal Model of a Severe Childhood Genetic Epileptic Encephalopathy.

The childhood epileptic encephalopathies (EE's) are seizure disorders that broadly impact development including cognitive, sensory and motor progress with severe consequences and comorbidities. Recently, mutations in DNM1 (dynamin 1) have been implicated in two EE syndromes, Lennox-Gastaut Syndrome and Infantile Spasms. Dnm1 encodes dynamin 1, a large multimeric GTPase necessary for activity-dependent membrane recycling in neurons, including synaptic vesicle endocytosis. Dnm1Ftfl or "fitful" mice carry a spontaneous mutation in the mouse ortholog of DNM1 and recapitulate many of the disease features associated with human DNM1 patients, providing a relevant disease model of human EE's. In order to examine the cellular etiology of seizures and behavioral and neurological comorbidities, we engineered a conditional Dnm1Ftfl mouse model of DNM1 EE. Observations of Dnm1Ftfl/flox mice in combination with various neuronal subpopulation specific cre strains demonstrate unique seizure phenotypes and clear separation of major neurobehavioral comorbidities from severe seizures associated with the germline model. This demonstration of pleiotropy suggests that treating seizures per se may not prevent severe comorbidity observed in EE associated with dynamin-1 mutations, and is likely to have implications for other genetic forms of EE.

Long-term prognosis of patients with Lennox--Gastaut syndrome in recent decades.

PURPOSE: We investigated long term prognosis of Lennox-Gastaut syndrome (LGS) with active application of recent advanced treatment modalities such as ketogenic diet (KD) or epilepsy surgery (ES). METHODS: We retrospectively evaluated 68 patients with LGS, aged 18-35 years. We assessed seizure outcomes for a range of therapeutic modalities. Evolution of seizure types, EEG characteristics, cognition, ambulation, social outcomes and other clinical data were also evaluated. RESULTS: For a mean follow-up duration of 19.3 years (range 8.3-32.5 years), finally sixteen patients (23.5%) were seizure-free. Of the 68 patients, 26 (38.2%) were treated solely with AEDs and six became seizure-free. The KD was administered to 19 patients, five patients maintained a seizure free state during the KD but only one patient was able to maintain a seizure free state by continuing on a modified Atkins diet. Focal resective surgery was performed in 15 patients, ten out of the 15 patients had Engel class I outcomes, but only three patients maintained seizure freedom to adults. CC was performed in 17 patients, and VNS was performed in 14 patients. These palliative procedures were also effective but had limitations to obtain and maintain seizure freedom to adults. Characteristic EEG features of diffuse slow spike-wave and generalized paroxysmal fast activity ceased in half of the patients. In cognitive terms, 94.7% of patients exhibited moderate to profound mental retardation. Only 39.7% of patients had intact independent daily living skills, and 25.4% could not walk, even with support. CONCLUSIONS: KD and epilepsy surgery were effective for seizure control, but they did not necessarily lead to the maintenance of a seizure-free state. LGS remains a form of intractable epilepsy despite the application of recent advanced treatment modalities.