Early onset absence epilepsy of childhood: Epidemiologic data, treatment and outcome in a sample of 56 patients born between 2000 and 2018.

PURPOSE: The aim of our work is to describe the characteristics of Early Onset Absence Epilepsy (EOAE) and to observe whether specific anamnestic, clinical or electroencephalographic characteristics can influence the drug sensitivity of this pathology. METHODS: We carried out a retrospective study of patients affected by absence epilepsy with onset under four years of age, born between January 1st 2000 and December 31st 2018, who were reffered to the Regional Epilepsy Center of Spedali Civili of Brescia. We then divided the sample into three groups based on the age of onset. RESULTS: Our sample is composed of 56 patients. Among the children with epilepsy onset under two years of age (11), all were still on therapy after three and six years of follow-up, and 64 % of them required polytherapy. Among patients with epilepsy onset between two and three years of age (24), 87 % were still on therapy after three years of follow-up and 68 % after six years of follow-up; 46 % of these subjects required polytherapy. Among patients with epilepsy onset between three and four years of age (21), 89 % were still on therapy after three years of follow-up and 38 % after six years of follow-up; 38 % of them required polytherapy. CONCLUSIONS: We observe that patients with an earlier epilepsy onset have a worse outcome and a lower drug sensitivity. This may allow to predict in which cases it would be appropriate to maintain antiseizure therapy for a prolonged period.

The landscape of drug resistant absence seizures in adolescents and adults: Pathophysiology, electroclinical spectrum and treatment options.

The persistence of typical absence seizures (AS) in adolescence and adulthood may reduce the quality of life of patients with genetic generalized epilepsies (GGEs). The prevalence of drug resistant AS is probably underestimated in this patient population, and treatment options are relatively scarce. Similarly, atypical absence seizures in developmental and epileptic encephalopathies (DEEs) may be unrecognized, and often persist into adulthood despite improvement of more severe seizures. These two seemingly distant conditions, represented by typical AS in GGE and atypical AS in DEE, share at least partially overlapping pathophysiological and genetic mechanisms, which may be the target of drug and neurostimulation therapies. In addition, some patients with drug-resistant typical AS may present electroclinical features that lie in between the two extremes represented by these generalized forms of epilepsy.

Lack of causal association between epilepsy and dementia: A Mendelian randomization analysis.

OBJECTIVE: Epidemiological studies have reported an association between epilepsy and dementia. However, the causal relationship between epilepsy and the risk of dementia is not clear. We aimed to inspect the causal effect of epilepsy on memory loss and dementia. METHODS: We analyzed summary data of epilepsy, memory loss, and dementia from the genome-wide association study (GWAS) using the two-sample Mendelian randomization (MR) method. We used the estimated odds ratio of memory loss and dementia associated with each of the genetically defined traits to infer evidence for a causal relationship with the following exposures: all epilepsy, focal epilepsy (including focal epilepsy with hippocampal sclerosis, lesion-negative focal epilepsy, and focal epilepsy with other lesions), and genetic generalized epilepsy (including childhood absence epilepsy, generalized tonic-clonic seizures alone, Juvenile absence epilepsy, and Juvenile myoclonic epilepsy). RESULTS: According to the result of MR using the inverse variance weighted method (IVW), we found that genetically predicted epilepsy did not causally increase the risk of memory loss and dementia (p > 0.05). Results of the MR-Egger and weighted median method were consistent with the IVW method. CONCLUSIONS: No evidence has been found to support the notion that epilepsy can result in memory loss and dementia. The associations observed in epidemiological studies could be attributed, in part, to confounding or nongenetic determinants.

Childhood Absence Epilepsy- Electroclinical Profile and Prevalence of Attention-Deficit/Hyperactivity Disorder Among a Cohort of 47 Children.

BACKGROUND: We aimed to find the proportion of attention-deficit/hyperactivity disorder (ADHD) among children with childhood absence epilepsy (CAE) and to describe their electroclinical features. METHODS: Video electroencephalography (EEG) was performed on 47 children who fulfilled International League Against Epilepsy criteria for CAE. These children were also assessed for the presence of ADHD. RESULTS: Of the 47 children, 27 (57%) met criteria for the diagnosis of ADHD. Majority (74%) of them had inattentive type of ADHD. Age at onset of absences ranged from three to 12 years (mean 7.2 ± 2.47). We analyzed 219 seizures (154 electroclinical and 65 electrographic). The average seizure duration was 7.1 seconds (range 1 to 38 [S.D. 5.81]). Of the 154 clinical absences, ictal discharges were less than or equal to two seconds in nine of 154 (5.8%); greater than two to less than or equal to four seconds in 33 of 154 (21.4%), and longer than 20 seconds in 11 of 154 (7%). The longest duration of ictal discharge recorded was 38 seconds, and the shortest duration was one second. The onset of ictal discharge had a "lead in" focus in 81% (177 of 219). CONCLUSIONS: The proportion of ADHD among children with CAE is high. A "lead in" focus of the generalized ictal discharges was observed frequently, lending support to the theory that the origin of seizure discharges in CAE is indeed cortical. The shortest ictal discharge recorded was one second.

[Idiopathic generalized epilepsies: Analysis of 101 patients]. / Epilepsias generalizadas idiopáticas: análisis de 101 pacientes.

INTRODUCTION: Idiopathic generalized epilepsies (IGI) are an electroclinical syndrome that includes four subsyndromes according to the ILAE 2017 classification. The long-term prognosis of these syndromes is uncertain due to the scarcity and heterogeneity of the studies. The objective of this study is to analyze the long-term prognosis of these syndromes, pharmacological treatment and the seizure recurrence. METHOD: Observational and retrospective study of a serie of patients diagnosed with EGI. Epidemiological variables, pharmacological treatment, freedom of seizures and recurrence after withdrawal of treatment were collected. RESULTS: We included 101 patients, the majority women (56.4%), with a median evolution of epilepsy of 17 years (interquartile range: 7-31). The most frequent syndrome was juvenile myoclonic epilepsy (46.5%), followed by epilepsy with generalized tonic-clonic seizures alone (25.7%), juvenile absence epilepsy (13.9%) and childhood absence epilepsy (13.9%). The 71.29% were on monotherapy and 20.79% on polytherapy, with significant differences between the different syndromes (P=.001). The most widely used drug was valproic acid. 39.6% presented seizure remission at 5 years, but we did not observe significant differences between the different syndromes (P=.982). The recurrence rate was 71.4% after withdrawal of treatment. CONCLUSION: Juvenile myoclonic epilepsy was the most frequent subtype of IGE. We observed significant differences in terms of polytherapy in the different syndromes, although not in the rates of remission of seizures at one year and at five years. The majority of patients with treatment withdrawal relapsed.

School performance and psychiatric comorbidity in childhood absence epilepsy: A Danish cohort study.

The aim was to determine school performance and psychiatric comorbidity in children with childhood absence epilepsy (CAE). We reviewed the medical records in children with ICD-10 codes for idiopathic generalized epilepsy before 18 years of age, and pediatric neurologists confirmed the International League Against Epilepsy criteria for CAE were met. Control groups were the general pediatric population or children with non-neurological chronic disease. Outcomes were from nationwide and population-based registers on school performance and psychiatric comorbidity. We compared the mean grade point average using linear regression and estimated hazard ratios (HR) using Cox regression for the other outcomes. Analyses were adjusted for the child's sex, and year of birth, and parental highest education, receipt of cash benefits or early disability pension. We included 114 children with CAE with a median age at onset of 5.9 years (interquartile range = 4.5-7.3 years). Compared with both population controls and non-neurological chronically ill children, children with CAE had increased hazard of special needs education (HR = 2.7, 95% confidence interval (CI) = 1.8-4.1, p < 0.0001), lower grade point average at 9th grade by 1.7 grade points (95% CI = -2.5 to -1.0, p < 0.001), increased ADHD medicine use (HR = 4.4, 95% CI = 2.7-7.2, p < 0.001), increased sleep medicine use (HR = 2.7, 95% CI = 1.7-4.3, p < 0.001), and increased psychiatry visits (HR = 2.1, 95% CI = 1.1-4.0, p = 0.03). In conclusion, children with CAE have increased psychiatric comorbidity and a considerable proportion of these children receive special needs education in primary/secondary school, albeit insufficient to normalize their considerably lower grade point average in the 9th grade.

School performance and psychiatric comorbidity in juvenile absence epilepsy and juvenile myoclonic epilepsy: a Danish population-based cohort study.

BACKGROUND: We aimed to determine school performance and psychiatric comorbidity in juvenile absence epilepsy (JAE), juvenile myoclonic epilepsy (JME), and generalized tonic-clonic seizures (GTCS) alone. METHODS: All children (< 18 years) fulfilled International League Against Epilepsy criteria after review of their medical records. Control groups were the pediatric background population or children with non-neurological chronic disease. Outcomes were on school performance and psychiatric comorbidity. We compared mean grade point averages using linear regression and estimated hazard ratios using Cox regression in the remaining analyses. We adjusted for the child's sex, age, and year of birth; and parental highest education, receipt of cash benefits or early retirement. RESULTS: We included 92 JAE, 190 JME, 27 GTCS alone, 15,084 non-neurological chronic disease controls, and population controls. JAE had two times increased hazard for special needs education compared with age-matched population controls (hazard ratio 2.2, 95% CI = 1.1‒4.6, p = 0.03); this was not seen in JME. Compared with population controls, both JAE and JME had lower grade point average in secondary and high school (JME: 9th grade: - 0.5 points, 95% CI = -0.9 to -0.06, p = 0.03; high school: - 0.6 points, 95% CI = -1.3 to -0.1, p = 0.04), and 8% fewer JME and 15% fewer JAE attended high school. Both JME and JAE had higher hazard for redeeming sleep medication compared with non-neurological chronic disease; additionally, JAE had increased hazard for ADHD medicine redemptions. CONCLUSIONS: Both JAE and JME had marginally poorer school performance; performance seemed worse in JAE than in JME. Both JAE and JME had increased use of sleep medication.

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.

Hyperventilation maneuver during EEG in children with epilepsy after the COVID-19 pandemic. Is a routine procedure necessary?

OBJECTIVE: Hyperventilation (HV) is one of the main and basic activation methods during ambulatory electroencephalogram (EEG), unless medical reasons contraindicate it. During the COVID-19 pandemic, with the high risk of human-to-human infection, local guidelines and recommendations have been developed that suggest not to perform the HV maneuver routinely. Our objective was to characterize patients who present positive HV in an epilepsy center. METHODS: We analyzed retrospectively all the ambulatory EEGs performed during one year in our specialized ambulatory child and adolescent epilepsy center, and describe patients with positive maneuver. RESULTS: A total of 305 EEGs were performed. Patients under 3 years and 11 months were excluded as well as all patients that did not fill up the criteria for epilepsy diagnosis. From the 252 EEGs that were included in the study, 194 EEGs (77%) were classified as abnormal and 58 (23%) as normal. From these same 252 EEGs, 150 EEG finished correctly the HV maneuver. Physiological slowing response was found in 54 EEGs (36%), no changes (negative) in 83 (55%), and abnormal response (positive) in 13 EEGs (9%). The 13 HV-positive EEGs showed 4 patients with an increase of epileptiform activity, 3 patients experienced an increase of basal preregistered abnormal slowing, and 6 EEGs showed trigger of bilaterally synchronous and symmetric 2-4 Hz spike-and-slow wave discharges and absences. None of these last 6 patients needed more than 3 minutes to elicit the paroxysmal discharge. SIGNIFICANCE: Based on these findings and according with other studies, the low positivity and high specificity of the HV maneuver support the idea that HV could be excluded during the COVID-19 pandemic situation, and also reevaluate whether it could be changed to a complementary maneuver, restricted only for cases where absence epilepsy is suspected. Larger studies will be needed to reaffirm this proposal.

Diagnosing and managing childhood absence epilepsy by telemedicine.

The diagnosis of childhood absence epilepsy (CAE) is typically based on history and description of spells, supported by an office-based positive hyperventilation test and confirmed by routine electroencephalography (EEG). In the current coronavirus disease 2019 (COVID-19) pandemic, many pediatric neurologists have switched to telemedicine visits for nonemergent outpatient evaluations. We present a series of children diagnosed as having CAE on the basis of a positive hyperventilation test performed during remote televisits. Several of these children were begun on treatment for CAE prior to obtaining an EEG, with significant seizure reduction. Our series documents the feasibility of CAE diagnosis and management by telemedicine.

Absence epilepsy: Characteristics, pathophysiology, attention impairments, and the related risk of accidents. A narrative review.

OBJECTIVE: Absence epilepsy (AE) is related to both cognitive and physical impairments. In this narrative review, we critically discuss the pathophysiology of AE and the impairment of attention in children and adolescents with AE. In particular, we contextualize the attentive dysfunctions of AE with the associated risks, such as accidental injuries. DATA SOURCE: An extensive literature search on attention deficits and the rate of accidental injuries in AE was run. The search was conducted on Scopus, Pubmed, and the online libraries of the University of Twente and Maastricht University. Relevant references of the included articles were added. Retrospective and prospective studies, case reports, meta-analysis, and narrative reviews were included. Only studies written in English were considered. Date of last search is February 2020. The keywords used were "absence epilepsy" AND "attention"/"awareness", "absence epilepsy" AND "accidental injuries"/"accident*"/"injuries". RESULTS: Ten retrospective and two prospective studies on cognition and AE were fully screened. Seventeen papers explicitly referring to attention in AE were reviewed. Just one paper was found to specifically focus on accidental injuries and AE, while twelve studies generally referring to epilepsy syndromes - among which AE - and related accidents were included. CONCLUSION: Absence epilepsy and attention deficits show some patterns of pathophysiological association. This relation may account for dysfunctions in everyday activities in the pediatric population. Particular metrics, such as the risk related to biking in children with AE, should be used in future studies to address the problem in a novel way and to impact clinical indications.

Idiopathic (genetic) generalized epilepsies with absences: clinical and electrographic characteristics and seizure outcome.

PURPOSE: We compared various syndromes of idiopathic (genetic) generalized epilepsy (IGE) with absences based on their demographic, clinical, and electroencephalographic (EEG) findings, and their seizure outcome. METHODS: In this retrospective study, all patients with a clinical diagnosis of childhood absence epilepsy (CAE), juvenile absence epilepsy (JAE), idiopathic epilepsy with phantom absences (PAs), and Jeavons syndrome (JS) were recruited at the outpatient epilepsy clinic at Shiraz University of Medical Sciences, from 2008 until 2019. Age, gender, age at seizure onset, seizure type(s), epilepsy risk factors, history of seizure-related injuries, EEG findings, and seizure outcome of all patients were registered routinely. RESULTS: Six hundred one patients with IGE were registered at our epilepsy clinic. Two hundred thirteen patients (35.4%) were diagnosed as having IGE with absences [111 patients (52.1%) had JAE, 82 patients (38.5%) had CAE, 12 people (5.6%) had JS, and eight patients (3.8%) had PA]. A history of experiencing generalized tonic-clonic seizures and a history of seizure-related injury were significantly different between the syndromes. There were no significant differences between the syndromes with regard to their EEG findings. Seizure outcome showed a trend to be different between the syndromes of IGE (p = 0.06). CONCLUSION: Syndromes of IGE with absences are common occurrences at epilepsy clinics. Making a syndromic diagnosis could have significant clinical implications. In doing so, interictal EEG cannot differentiate between different syndromes of IGE and the key element in making a correct syndromic diagnosis is a detailed clinical history.

Treatment of epilepsy in adults: Expert opinion in South Korea.

OBJECTIVE: The aim of this study was to gather the expert opinions of Korean epileptologists regarding the treatment of adult patients with epilepsy. METHODS: A total of 42 neurologists who specialized in epilepsy were surveyed. They completed an online questionnaire describing multiple patient scenarios. Using these scenarios, they evaluated treatment strategies and gave their preference for specific antiepileptic drugs (AEDs) used to treat genetically mediated generalized epilepsy and focal epilepsy. RESULTS: Initial AED monotherapy, followed by a second form of alternative monotherapy or an add-on combination therapy, was the preferred treatment strategy. The experts reached consensus for 87.2% of the items. The most commonly selected AEDs for the initial monotherapy for patients with generalized epilepsy were levetiracetam or valproate. For those with focal epilepsy, levetiracetam, oxcarbazepine, or lamotrigine were the most popular selections. Ethosuximide was the treatment of choice only for patients with generalized epilepsy with prominent absence seizures. Levetiracetam was preferred as an add-on therapy for both generalized and focal epilepsy. For special populations of patients, such as elderly adults or those with comorbid diseases, levetiracetam or lamotrigine was selected as the treatment of choice. CONCLUSION: Most of the survey results were in accordance with the US expert opinion survey published in 2016. This survey can assist clinicians in making clinical decisions when treating individual adult patients with epilepsy.

De novo SCN1A, SCN8A, and CLCN2 mutations in childhood absence epilepsy.

This study aimed to identify monogenic mutations from Chinese patients with childhood absence epilepsy (CAE) and summarize their characteristics. A total of 100 patients with CAE were recruited in Peking University First Hospital from 2005 to 2016 and underwent telephone and outpatient follow-up review. We used targeted disease-specific gene capture sequencing (involving 300 genes) to identify pathogenic variations for these patients. We identified three de novo epilepsy-related gene mutations, including missense mutations of SCN1A (c. 5399 T > A; p. Val1800Asp), SCN8A (c. 2371 G > T; p. Val791Phe), and CLCN2 (c. 481 G > A; p. Gly161Ser), from three patients, separately. All recruited patients presented typical CAE features and good prognosis. To date, CAE has been considered a complex disease caused by multiple susceptibility genes. In this study, we observed that 3% of typical CAE patients had a de novo mutation of a known monogenic epilepsy-related gene. Our study suggests that a significant proportion of typical CAE cases may be monogenic forms of epilepsy. For genetic generalized epilepsies, such as CAE, further studies are needed to clarify the contributions of de novo or inherited rare monogenic coding, noncoding and copy number variants.

Epilepsia ausencia infantil. Pronóstico a largo plazo / Long-term prognosis of childhood absence epilepsy

Introducción: La epilepsia ausencia infantil (EAI) se considera una forma de epilepsia de fácil control farmacológico solo si se emplean criterios estrictos para la clasificación de los pacientes. Supone el 10% de las epilepsias infantiles de inicio antes de los 15 años y es más frecuente en niñas escolares. El objetivo es conocer la evolución a largo plazo de los pacientes atendidos en la etapa infantil con EAI empleando los criterios de Loiseau y Panayiotopoulos Métodos: Estudio retrospectivo de 69 pacientes con EAI con edad actual mayor de 11 años, realizado mediante revisión de historias clínicas, EEG y cuestionario telefónico. Resultados: Cumplieron los criterios de Loiseau y Panayiotopoulos 52 pacientes, edad actual media 17,61 años. Relación mujeres/hombres: 1,65/1; edad de inicio media: 6 años y 2 meses; duración total de tratamiento media: 3 años y 9 meses; antecedentes familiares de epilepsia: 30,8%; antecedentes personales de crisis febriles: 7,7%; tipo de ausencias: simples 73,5%, complejas: 26,5%; respuesta al primer tratamiento: ácido valproico 46,3% o ácido valproico con etosuximida simultáneos 90,9%; respuesta al segundo tratamiento (etosuximida o lamotrigina) 84,2%; crisis tras supresión de tratamiento: 4%; pacientes en remisión terminal: 78,8%; necesidad de apoyo psicopedagógico: 25%. Conclusiones: Nuestros datos muestran la utilidad de clasificar a los pacientes utilizando criterios estrictos ya que el pronóstico de las crisis del síndrome de EAI puro es excelente. Encontramos que la tasa de recaídas ha sido muy baja. A pesar del favorable pronóstico en cuanto al control de crisis necesitan apoyos psicopedagógicos en un alto porcentaje

Introduction: Childhood absence epilepsy (CAE) is considered easily manageable with medication provided that a strict patient classification system is employed. It accounts for 10% of all childhood epilepsy cases starting before the age of 15 and it is most frequent in school-aged girls. The aim of this study is to analyse long-term outcomes of patients diagnosed with CAE according to the Loiseau and Panayiotopoulos criteria and treated during childhood. Methods: We conducted a retrospective study including 69 patients with CAE who are currently older than 11; data were gathered from medical histories, EEG records, and telephone questionnaires. Results: 52 patients met the Loiseau and Panayiotopoulos criteria. Mean age is now 17.16 years. Female-to-male ratio was 1.65:1; mean age at onset was 6 years and 2 months; mean duration of treatment was 3 years and 9 months. A family history of epilepsy was present in 30.8% of the patients and 7.7% had a personal history of febrile convulsions. Absence seizures were simple in 73.5% of the patients and complex in 26.5%. Response rates to first-line treatment were as follows: valproic acid, 46.3%; and valproic acid plus ethosuximide, 90.9%. The rate of response to second-line therapy (ethosuximide or lamotrigine) was 84.2%; 4% of the patients experienced further seizures after treatment discontinuation, 78.8% achieved seizure remission, and 25% needed psychological and academic support. Conclusions: Our data show that epileptic patients should be classified according to strict diagnostic criteria since patients with true CAE have an excellent prognosis. The relapse rate was very low in our sample. Despite the favourable prognosis, psychological and academic support is usually necessary

No evidence for a BRD2 promoter hypermethylation in blood leukocytes of Europeans with juvenile myoclonic epilepsy.

Juvenile myoclonic epilepsy (JME) is a common syndrome of genetic generalized epilepsies (GGEs). Linkage and association studies suggest that the gene encoding the bromodomain-containing protein 2 (BRD2) may increase risk of JME. The present methylation and association study followed up a recent report highlighting that the BRD2 promoter CpG island (CpG76) is differentially hypermethylated in lymphoblastoid cells from Caucasian patients with JME compared to patients with other GGE subtypes and unaffected relatives. In contrast, we found a uniform low average percentage of methylation (<4.5%) for 13 CpG76-CpGs in whole blood cells from 782 unrelated European Caucasians, including 116 JME patients, 196 patients with genetic absence epilepsies, and 470 control subjects. We also failed to confirm an allelic association of the BRD2 promoter single nucleotide polymorphism (SNP) rs3918149 with JME (Armitage trend test, P = 0.98), and we did not detect a substantial impact of SNP rs3918149 on CpG76 methylation in either 116 JME patients (methylation quantitative trait loci [meQTL], P = 0.29) or 470 German control subjects (meQTL, P = 0.55). Our results do not support the previous observation that a high DNA methylation level of the BRD2 promoter CpG76 island is a prevalent epigenetic motif associated with JME in Caucasians.

EEG of asymptomatic first-degree relatives of patients with juvenile myoclonic, childhood absence and rolandic epilepsy: a systematic review and meta-analysis.

Rolandic (RE), childhood absence (CAE) and juvenile myoclonic (JME) epilepsy encompass centrotemporal sharp waves, 3-Hz spike waves and >3-Hz spike or polyspike waves, respectively. Evidence abounds for genetic roles in all three syndromes, yet involved genes for the vast majority of patients remain unknown. It has long been proposed that while each disease is genetically complex, its specific EEG trait may represent a genetically simpler endophenotype. This meta-analysis of the literature focuses on the frequency of EEG traits in clinically unaffected first-degree relatives towards determining inheritance patterns of the EEG endophenotypes. We used the Preferred Reporting Items for Systematic Review and Meta-Analysis for protocols (PRISMA-P) and searched Medline, EMBASE, CINHAL and the Cochrane Central Register of Controlled Trials. Following extensive screening, 15 studies were included with a total of 3,858 asymptomatic relatives. The prevalence of 'abnormal' EEG waves was 21%, 42% and 33% for JME, CAE and RE, respectively, close to what would be expected based on Mendelian inheritance. However, breaking down the reported EEG abnormalities, most consisted not of the respective EEG signature traits -prevalences of which were as low as 5%- but of non-specific EEG 'abnormalities'/variants. Prevalence of non-specific EEG 'abnormalities'/variants in the general population ranges from 0.1 to 10%. Underlying this 100-fold-wide range is a spectrum of what is considered 'abnormal' or variant. The prevalences of 'abnormalities'/variants in asymptomatic siblings in RE, CAE and JME significantly exceed even the highest value in the general population and fall within Mendelian expectations. These results suggest that EEG 'abnormalities'/variants shared with the general population are enriched in the three syndromes and are endophenotypes inherited in a genetically simple near-Mendelian fashion. Future work with modern EEG variant definitions should uncover genetic variants contributing to neuronal hypersynchrony in epilepsy.

Electroclinical Features of Generalized Paroxysmal Fast Activity in Typical Absence Seizures.

PURPOSE: Generalized paroxysmal fast activity (GPFA) is a diffuse, paroxysmal, frontal predominant activity described in patients with generalized epilepsies. Studies specifically focusing on electroclinical features of typical absence seizures in children have not reported any GPFA-like features. We sought to identify GPFA in children with typical absence seizures, study its incidence, characteristic electroclinical features, and effect on their epilepsy. METHODS: We performed a retrospective review of electroencephalograms of children with diagnosis of absence epilepsy. A total of 173 subjects were identified. In subjects with GPFA on their electroencephalograms, GPFA characteristics were collected (i.e., predominant location, duration, amplitude, frequency, provocation factors, and if GPFA was followed by spike-wave discharges). In GPFA-positive subjects, further data sets were collected examining their demographics, duration of epilepsy, and pharmacoresponsiveness to epilepsy. RESULTS: Generalized paroxysmal fast activity was identified in 10 subjects (5.78%) with female to male ratio of 9:1. Median age of subjects was 17 years, and median duration of illness was 9.5 years. Mean maximum GPFA amplitude was 88.3 µV with posterior predominance in 9/10 subjects. Generalized paroxysmal fast activity frequency ranged between 11 and 20 Hz with duration of 1 to 4 seconds. Generalized paroxysmal fast activity was provoked with eye closure, hyperventilation, and photic stimulation. Antiseizure medications had no effect on GPFA, and epilepsy was well controlled in most subjects. CONCLUSIONS: Generalized paroxysmal fast activity is uncommon in children with typical absence seizures and has medium voltage, posterior predominance, and marked female preponderance. Generalized paroxysmal fast activity is seen during both pharmacoresponsive and drug-resistant epilepsy, and is not affected by antiseizure medications. It may serve as an independent marker of lifelong epilepsy.

Relapse after treatment withdrawal of antiepileptic drugs for Juvenile Absence Epilepsy and Juvenile Myoclonic Epilepsy.

PURPOSE: Conventional teaching is that juvenile myoclonic epilepsy (JME) and juvenile absence epilepsy (JAE) require lifelong antiepileptic drug (AED) treatment. We therefore wanted to determine how many patients attending our epilepsy service with JAE or JME went into 2 year remission, and then relapsed, both off and on AEDs. METHOD: This was a retrospective case-notes review. Patients with JAE and JME were systematically ascertained from clinic lists and databases at one teaching hospital. Data was extracted systematically. Simple descriptive statistics were used. RESULTS: JAE: 14/36 (39%) were seizure free on AEDs for at least 2 years. Of the 6 (43%) attempting AED withdrawal, all (100%) relapsed, compared with only 25% of those who did not withdraw AEDs. Only 2/5 who relapsed and restarted AEDs regained remission. JME: 32/145 (22%) were seizure free on AEDs for at least 2 years. Of the 10 (31%) attempting AED withdrawal, 8 (80%) relapsed, compared with only 36% of those who did not withdraw AEDs. Only 2/8 who relapsed and restarted AEDs regained remission. CONCLUSION: Remission rates for JAE and JME was lower than expected. Higher proportions of seizure free patients underwent physician-supervised withdrawal than anticipated. Relapse rates off AEDs were similar for JAE and JME, and at least twice as high as for those remaining on AEDs, and a further remission was not invariable on restarting AEDs. Our experience, comparing relapse in those withdrawing to those staying on AEDs will help in discussions with patients keen to try AED withdrawal.

Absence epilepsy beyond adolescence: an outcome analysis after 45 years of follow-up.

OBJECTIVES: Depending on patient age at onset, absence epilepsy is subdivided into childhood and juvenile forms. Absence seizures can occur several times per day (pyknoleptic course) or less frequently than daily (non-pyknoleptic course). Seizures typically terminate before adulthood, but a quarter of patients need ongoing treatment beyond adolescence. Little is known about their long-term seizure and psychosocial outcome. METHODS: Files of 135 outpatients with absence epilepsy (76 females; 123 had additional generalised tonic-clonic seizures) were retrospectively analysed after a median follow-up of 45.4 years (IQR: 31.9-56.2). Eighty-two subjects completed an additional interview. Patients were dichotomised according to age at epilepsy onset (childhood: n=82; juvenile: n=53) and course of absence seizures (pyknoleptic: n=80; non-pyknoleptic: n=55). RESULTS: Among all patients, 53% achieved 5-year terminal seizure remission, 16% without antiepileptic medication. Median age at last seizure was lower in patients with childhood onset of absence epilepsy (37.7 years) versus juvenile onset (44.4 years; P≤0.01). However, rates and duration of terminal seizure remission were similar. Pyknoleptic versus non-pyknoleptic course of absence seizures made no difference for long-term seizure outcome. Multivariate analysis identified only higher age at investigation to be associated with terminal 5-year seizure remission. Regarding aspects of psychosocial outcome, there were no significant differences between the respective subgroups. CONCLUSIONS: These data indicate that if absence epilepsy persists beyond adolescence, long-term seizure and psychosocial outcome do not differ between childhood and juvenile onset or between pyknoleptic and non-pyknoleptic course of absence epilepsy. However, higher patient age increases the chance of terminal seizure remission.