Pharmacokinetic Variability of Rufinamide and Stiripentol in Children with Refractory Epilepsy: A Retrospective Study of Therapeutic Drug Monitoring from the National Epilepsy Centers in Denmark and Norway.

BACKGROUND: Rufinamide and stiripentol, orphan drugs used in Lennox-Gastaut and Dravet syndromes, respectively, are antiseizure medications (ASMs), often administered to children; however, pharmacokinetic studies are lacking. The authors compared the pharmacokinetic variability of these drugs with respect to the dose, serum concentrations, comedication, age, and duration of treatment. METHODS: Children and adolescents (<18 years) whose serum concentrations were measured were retrospectively identified from the therapeutic drug monitoring (TDM) databases at 2 national epilepsy centers in Norway and Denmark (2012-2021). RESULTS: Data from 165 patients (56% boys/44% girls) treated with rufinamide and 52 patients (50% boys/50% girls) treated with stiripentol were included. For rufinamide, the median age was 10 (range 2-17) years, dose 23 (3-73) mg/d, and serum concentration 34 (3-227) µmol/L [8.1 mg/L (0.71-54.0 mg/L)]. For stiripentol, the median age was 8.5 (range 1-17) years, dose 37 (18-76) mg/d, and serum concentration 33 (4-113) µmol/L [7.7 mg/L (0.93-26.3 mg/L)]. The concomitant use of 1-9 other ASMs during the data collection was noted. Pharmacokinetic variability, calculated as the concentration/(dose/kg) ratio, ranged from 0.26 to 11.31 (µmol/L)/(mg/kg) for rufinamide and 0.17-1.52 (µmol/L)/(mg/kg) for stiripentol. The intraindividual coefficients of variation ranged widely, from 5% to 110% for rufinamide and 11%-117% for stiripentol. The treatment period was at least 5 years in 50% of patients. No statistically significant effects of age, sex, or ASM comedication were observed, possibly due to the small sample size and heterogeneous groups with variable seizure situations, comorbidities, and changes in comedication and physiology. CONCLUSIONS: This study demonstrates considerable pharmacokinetic variability in and between patients for both drugs and similar use in terms of age, burden of comedication and retention rates. TDM may be useful in the clinical setting to monitor and optimize treatment in this vulnerable patient group.

Fenfluramine in the treatment of Dravet syndrome: Results of a third randomized, placebo-controlled clinical trial.

OBJECTIVE: This study was undertaken to assess the safety and efficacy of fenfluramine in the treatment of convulsive seizures in patients with Dravet syndrome. METHODS: This multicenter, randomized, double-blind, placebo-controlled, parallel-group, phase 3 clinical trial enrolled patients with Dravet syndrome, aged 2-18 years with poorly controlled convulsive seizures, provided they were not also receiving stiripentol. Eligible patients who had ≥6 convulsive seizures during the 6-week baseline period were randomized to placebo, fenfluramine .2 mg/kg/day, or fenfluramine .7 mg/kg/day (1:1:1 ratio) administered orally (maximum dose = 26 mg/day). Doses were titrated over 2 weeks and maintained for an additional 12 weeks. The primary endpoint was a comparison of the monthly convulsive seizure frequency (MCSF) during baseline and during the combined titration-maintenance period in patients given fenfluramine .7 mg/kg/day versus patients given placebo. RESULTS: A total of 169 patients were screened, and 143 were randomized to treatment. Mean age was 9.3 ± 4.7 years (±SD), 51% were male, and median baseline MCSF in the three groups ranged 12.7-18.0 per 28 days. Patients treated with fenfluramine .7 mg/kg/day demonstrated a 64.8% (95% confidence interval = 51.8%-74.2%) greater reduction in MCSF compared with placebo (p < .0001). Following fenfluramine .7 mg/kg/day, 72.9% of patients had a ≥50% reduction in MCSF compared with 6.3% in the placebo group (p < .0001). The median longest seizure-free interval was 30 days in the fenfluramine .7 mg/kg/day group compared with 10 days in the placebo group (p < .0001). The most common adverse events (>15% in any group) were decreased appetite, somnolence, pyrexia, and decreased blood glucose. All occurred in higher frequency in fenfluramine groups than placebo. No evidence of valvular heart disease or pulmonary artery hypertension was detected. SIGNIFICANCE: The results of this third phase 3 clinical trial provide further evidence of the magnitude and durability of the antiseizure response of fenfluramine in children with Dravet syndrome.

PRRT2 benign familial infantile seizures (BFIS) with atypical evolution to encephalopathy related to status epilepticus during sleep (ESES).

PURPOSE: Heterozygous variants in PRRT2 are mostly associated with benign phenotypes, being the major genetic cause of benign familial infantile seizures (BFIS), as well as in paroxysmal disorders. We report two children from unrelated families with BFIS that evolved to encephalopathy related to status epilepticus during sleep (ESES). METHODS AND RESULTS: Two probands presented with focal motor seizures at 3 months of age, with a limited course. Both children presented, at around 5 years of age, with centro-temporal interictal epileptiform discharges with a source in the frontal operculum, markedly activated by sleep, and associated with stagnation on neuropsychological development. Whole-exome sequencing and co-segregation analysis revealed a frameshift mutation c.649dupC in the proline-rich transmembrane protein 2 (PRRT2) in both probands and all affected family members. CONCLUSION: The mechanism leading to epilepsy and the phenotypic variability of PRRT2 variants remain poorly understood. However, its wide cortical and subcortical expression, in particular in the thalamus, could partially explain both the focal EEG pattern and the evolution to ESES. No variants in the PRRT2 gene have been previously reported in patients with ESES. Due to the rarity of this phenotype, other possible causative cofactors are likely contributing to the more severe course of BFIS in our probands.

Fenfluramine hydrochloride for the treatment of seizures in Dravet syndrome: a randomised, double-blind, placebo-controlled trial.

BACKGROUND: Dravet syndrome is a rare, treatment-resistant developmental epileptic encephalopathy characterised by multiple types of frequent, disabling seizures. Fenfluramine has been reported to have antiseizure activity in observational studies of photosensitive epilepsy and Dravet syndrome. The aim of the present study was to assess the efficacy and safety of fenfluramine in patients with Dravet syndrome. METHODS: In this randomised, double-blind, placebo-controlled clinical trial, we enrolled children and young adults with Dravet syndrome. After a 6-week observation period to establish baseline monthly convulsive seizure frequency (MCSF; convulsive seizures were defined as hemiclonic, tonic, clonic, tonic-atonic, generalised tonic-clonic, and focal with clearly observable motor signs), patients were randomly assigned through an interactive web response system in a 1:1:1 ratio to placebo, fenfluramine 0·2 mg/kg per day, or fenfluramine 0·7 mg/kg per day, added to existing antiepileptic agents for 14 weeks. The primary outcome was the change in mean monthly frequency of convulsive seizures during the treatment period compared with baseline in the 0·7 mg/kg per day group versus placebo; 0·2 mg/kg per day versus placebo was assessed as a key secondary outcome. Analysis was by modified intention to treat. Safety analyses included all participants who received at least one dose of study medication. This trial is registered with ClinicalTrials.gov with two identical protocols NCT02682927 and NCT02826863. FINDINGS: Between Jan 15, 2016, and Aug 14, 2017, we assessed 173 patients, of whom 119 patients (mean age 9·0 years, 64 [54%] male) were randomly assigned to receive either fenfluramine 0·2 mg/kg per day (39), fenfluramine 0·7 mg/kg per day (40) or placebo (40). During treatment, the median reduction in seizure frequency was 74·9% in the fenfluramine 0·7 mg/kg group (from median 20·7 seizures per 28 days to 4·7 seizures per 28 days), 42·3% in the fenfluramine 0·2 mg/kg group (from median 17·5 seizures per 28 days to 12·6 per 28 days), and 19·2% in the placebo group (from median 27·3 per 28 days to 22·0 per 28 days). The study met its primary efficacy endpoint, with fenfluramine 0·7 mg/kg per day showing a 62·3% greater reduction in mean MCSF compared with placebo (95% CI 47·7-72·8, p<0·0001); fenfluramine 0·2 mg/kg per day showed a 32·4% reduction in mean MCSF compared with placebo (95% CI 6·2-52·3, p=0·0209). The most common adverse events (occurring in at least 10% of patients and more frequently in the fenfluramine groups) were decreased appetite, diarrhoea, fatigue, lethargy, somnolence, and decreased weight. Echocardiographic examinations revealed valve function within the normal physiological range in all patients during the trial and no signs of pulmonary arterial hypertension. INTERPRETATION: In Dravet syndrome, fenfluramine provided significantly greater reduction in convulsive seizure frequency compared with placebo and was generally well tolerated, with no observed valvular heart disease or pulmonary arterial hypertension. Fenfluramine could be an important new treatment option for patients with Dravet syndrome. FUNDING: Zogenix.

Testing association of rare genetic variants with resistance to three common antiseizure medications.

OBJECTIVE: Drug resistance is a major concern in the treatment of individuals with epilepsy. No genetic markers for resistance to individual antiseizure medication (ASM) have yet been identified. We aimed to identify the role of rare genetic variants in drug resistance for three common ASMs: levetiracetam (LEV), lamotrigine (LTG), and valproic acid (VPA). METHODS: A cohort of 1622 individuals of European descent with epilepsy was deeply phenotyped and underwent whole exome sequencing (WES), comprising 575 taking LEV, 826 LTG, and 782 VPA. We performed gene- and gene set-based collapsing analyses comparing responders and nonresponders to the three drugs to determine the burden of different categories of rare genetic variants. RESULTS: We observed a marginally significant enrichment of rare missense, truncating, and splice region variants in individuals who were resistant to VPA compared to VPA responders for genes involved in VPA pharmacokinetics. We also found a borderline significant enrichment of truncating and splice region variants in the synaptic vesicle glycoprotein (SV2) gene family in nonresponders compared to responders to LEV. We did not see any significant enrichment using a gene-based approach. SIGNIFICANCE: In our pharmacogenetic study, we identified a slightly increased burden of damaging variants in gene groups related to drug kinetics or targeting in individuals presenting with drug resistance to VPA or LEV. Such variants could thus determine a genetic contribution to drug resistance.

The impact of severe pediatric epilepsy on experienced stress and psychopathology in parents.

OBJECTIVES: To assess the prevalence of psychopathology and the level of stress in parents of children with severe epilepsy to gain a better understanding of parental support needs. METHODS: Questionnaires were completed by parents of children with severe epilepsy during the hospitalization of their child at the Danish Epilepsy Center. The questions targeted symptoms of post-traumatic stress disorder (PTSD), complex PTSD (CPTSD), depression, and anxiety, and the level of perceived stress. RESULTS: A total of 162 caregivers of 140 children with epilepsy participated in the survey. Mothers were more often unemployed than fathers (38% vs. 11%, p < 0.01), and nearly half of the children (47%) attended special needs classes. Psychopathology symptoms were found in 43.5% of parents, fulfilling criteria for one or more diagnoses, and an additional 11% showed symptoms of sub-clinical PTSD. Parent-rated child difficulties were significantly associated with PTSD (Mdiff = 5.51, p = 0.001), depression (Mdiff = 4.50, p < 0.000), and anxiety (Mdiff = 4.61, p = 0.01), and with higher levels of perceived stress (p < 0.001). CONCLUSION: Caring for a child with severe epilepsy has a significant psychopathological impact on caregivers. Caregivers' resources and the degree of behavioral difficulties in the child, rather than epilepsy-related factors, are highly correlated with distress and psychopathological symptoms in caregivers.

Pharmacokinetic Variability and Clinical Use of Lacosamide in Children and Adolescents in Denmark and Norway.

BACKGROUND: The indication for the antiepileptic drug lacosamide (LCM) was recently extended to include children from the age of 4 years. Real-life data on the use and serum concentrations of LCM in children and adolescents are limited. The purpose of this study was to investigate the use of LCM in this patient group in relation to age, comedication, dose, serum concentrations and duration of treatment, and to examine pharmacokinetic variability. METHODS: Children and adolescents (<18 years) who had serum concentrations of LCM measured from January 2012 to June 2018 were retrospectively identified from the therapeutic drug monitoring databases at 2 national epilepsy centers in Norway and Denmark. Clinical data were collected from request forms and medical records. RESULTS: Data from 124 patients were included, 61 girls/63 boys. Weight was available for 76 patients. Median age was 15 years (range 2-17 years), dose of LCM 300 mg/d (76-600 mg/d), and serum concentration 18 µmol/L (5-138 µmol/L) [4.5 mg/L (1.3-34.5 mg/L)]. Pharmacokinetic variability was demonstrated as the concentration/(dose/kg) ratio ranged from 1.3 to 9.4 (µmol/L)/(mg/kg) and was affected by age. Polytherapy with 1-3 other antiepileptic drugs was noted in 107 patients (86%). Treatment was continued beyond 1 year in 71% (n = 45) of the 63 patients where such information was available, and all of these 45 patients had serum concentrations within the defined reference range. The 1-year retention rate was higher in patients not concomitantly using other sodium channel-blocking drugs (82% versus 56%). CONCLUSIONS: The study demonstrates pharmacokinetic variability in and between age groups, which indicates usefulness of therapeutic drug monitoring. More than two-thirds of patients continued treatment beyond 1 year, suggesting reasonable effectiveness.

Idiopathic encephalopathy related to status epilepticus during slow sleep (ESES) as a "pure" model of epileptic encephalopathy. An electroclinical, genetic, and follow-up study.

OBJECTIVE: The objective of the study was to investigate electroclinical and neuropsychological features, genetic background, and evolution of children with idiopathic encephalopathy with status epilepticus during slow sleep (ESES), including Landau-Kleffner syndrome (LKS). MATERIAL AND METHODS: All children diagnosed with idiopathic ESES at the Danish Epilepsy Centre between March 2003 and December 2014 were retrospectively reviewed. Repeated 24-hour electroencephalography (24-h EEG) recordings, neuropsychological assessments, and clinical-neurological evaluation were performed throughout the follow-up in all patients. In 13 children, genetic investigations were performed. RESULTS: We collected 24 children (14 males and 10 females). Mean age at ESES diagnosis was 6 years, and mean ESES duration was 2 years and 7 months. Twenty-one children had epileptic seizures. Three children had LKS. Topography of sleep-related EEG epileptic abnormalities was diffuse in 3 subjects, hemispheric in 6, multifocal in 9, and focal in 6. During the active phase of ESES, all children presented with a heterogeneous combination of behavioral and cognitive disturbances. In 14 children, a parallel between severity of the clinical picture and spike-wave index (SWI) was observed. We could not find a strict correlation between the type and severity of neurobehavioral impairment and the side/topography of sleep-related EEG discharges during the active phase of ESES. At the last follow-up, 21 children were in remission from ESES. Complete recovery from neurobehavioral disorders was observed in 5 children. Genetic assessment, performed in 13 children, showed GRIN2A variant in two (15.4%). SIGNIFICANCE: Our patients with idiopathic ESES showed a heterogeneous pattern of epileptic seizures, neurobehavioral disorders, and sleep EEG features. Only one-fourth of children completely recovered from the neuropsychological disturbances after ESES remission. Lack of correlation between severity/type of cognitive derangement and SWI and/or topography of sleep EEG epileptic abnormalities may suggest the contribution of additional factors (including impaired sleep homeostasis due to epileptic activity) in the neurobehavioral derangement that characterize ESES.

Mutations in the GABA Transporter SLC6A1 Cause Epilepsy with Myoclonic-Atonic Seizures.

GAT-1, encoded by SLC6A1, is one of the major gamma-aminobutyric acid (GABA) transporters in the brain and is responsible for re-uptake of GABA from the synapse. In this study, targeted resequencing of 644 individuals with epileptic encephalopathies led to the identification of six SLC6A1 mutations in seven individuals, all of whom have epilepsy with myoclonic-atonic seizures (MAE). We describe two truncations and four missense alterations, all of which most likely lead to loss of function of GAT-1 and thus reduced GABA re-uptake from the synapse. These individuals share many of the electrophysiological properties of Gat1-deficient mice, including spontaneous spike-wave discharges. Overall, pathogenic mutations occurred in 6/160 individuals with MAE, accounting for ~4% of unsolved MAE cases.

Real-world data on rufinamide treatment in patients with Lennox-Gastaut syndrome: Results from a European noninterventional registry study.

INTRODUCTION: Rufinamide is approved for the adjunctive treatment of seizures associated with Lennox-Gastaut syndrome (LGS) in patients aged ≥4years. The objective of this study was to provide real-world, long-term data on patients with LGS initiating rufinamide as add-on therapy and patients with LGS receiving other antiepileptic drugs (AEDs). METHODS: A Phase IV, noninterventional, multicenter registry study was conducted in patients with LGS aged ≥4years requiring modification to any AED treatment, including initiation of add-on rufinamide therapy. Safety/tolerability was assessed by evaluating treatment-emergent adverse events (TEAEs), and efficacy was assessed using a generic seizure frequency scale. RESULTS: A total of 111 patients from 64 sites in 8 European countries were included, of whom 64 initiated rufinamide ("rufinamide" group) and 21 did not receive rufinamide at any time during the study ("no-rufinamide" group). Mean ages were 16.1years (rufinamide) and 15.0years (no rufinamide). The median duration of follow-up was >2years (range: 1.3-46.4months). Antiepileptic drug-related TEAEs were reported for 40.6% (rufinamide) and 33.3% (no rufinamide) of patients and led to discontinuation of 7.8% and 4.8%, respectively. The most frequently reported rufinamide-related TEAEs (≥5% patients) were somnolence (7.8%) and decreased appetite (6.3%). There were no unexpected safety/tolerability findings. At month 12, the proportion of patients with improvement in all seizures ("much improved" or "very much improved") was 28.6% (12/42) for the rufinamide group and 14.3% (2/14) for the no-rufinamide group. CONCLUSION: The study provided valuable information on LGS and its management, and evidence that rufinamide has a consistent and generally favorable safety/tolerability profile when used in routine clinical practice. CLINICALTRIALS. GOV IDENTIFIER: NCT01991041.

The role of SLC2A1 mutations in myoclonic astatic epilepsy and absence epilepsy, and the estimated frequency of GLUT1 deficiency syndrome.

The first mutations identified in SLC2A1, encoding the glucose transporter type 1 (GLUT1) protein of the blood-brain barrier, were associated with severe epileptic encephalopathy. Recently, dominant SLC2A1 mutations were found in rare autosomal dominant families with various forms of epilepsy including early onset absence epilepsy (EOAE), myoclonic astatic epilepsy (MAE), and genetic generalized epilepsy (GGE). Our study aimed to investigate the possible role of SLC2A1 in various forms of epilepsy including MAE and absence epilepsy with early onset. We also aimed to estimate the frequency of GLUT1 deficiency syndrome in the Danish population. One hundred twenty patients with MAE, 50 patients with absence epilepsy, and 37 patients with unselected epilepsies, intellectual disability (ID), and/or various movement disorders were screened for mutations in SLC2A1. Mutations in SLC2A1 were detected in 5 (10%) of 50 patients with absence epilepsy, and in one (2.7%) of 37 patient with unselected epilepsies, ID, and/or various movement disorders. None of the 120 MAE patients harbored SLC2A1 mutations. We estimated the frequency of SLC2A1 mutations in the Danish population to be approximately 1:83,000. Our study confirmed the role of SLC2A1 mutations in absence epilepsy with early onset. However, our study failed to support the notion that SLC2A1 aberrations are a cause of MAE without associated features such as movement disorders.

Mutations in KCNT1 cause a spectrum of focal epilepsies.

Autosomal dominant mutations in the sodium-gated potassium channel subunit gene KCNT1 have been associated with two distinct seizure syndromes, nocturnal frontal lobe epilepsy (NFLE) and malignant migrating focal seizures of infancy (MMFSI). To further explore the phenotypic spectrum associated with KCNT1, we examined individuals affected with focal epilepsy or an epileptic encephalopathy for mutations in the gene. We identified KCNT1 mutations in 12 previously unreported patients with focal epilepsy, multifocal epilepsy, cardiac arrhythmia, and in a family with sudden unexpected death in epilepsy (SUDEP), in addition to patients with NFLE and MMFSI. In contrast to the 100% penetrance so far reported for KCNT1 mutations, we observed incomplete penetrance. It is notable that we report that the one KCNT1 mutation, p.Arg398Gln, can lead to either of the two distinct phenotypes, ADNFLE or MMFSI, even within the same family. This indicates that genotype-phenotype relationships for KCNT1 mutations are not straightforward. We demonstrate that KCNT1 mutations are highly pleiotropic and are associated with phenotypes other than ADNFLE and MMFSI. KCNT1 mutations are now associated with Ohtahara syndrome, MMFSI, and nocturnal focal epilepsy. They may also be associated with multifocal epilepsy and cardiac disturbances.

Effectiveness and tolerability of perampanel in children and adolescents with refractory epilepsies: first experiences.

OBJECTIVE: This article aims to report the first clinical experiences concerning effectiveness and tolerability of perampanel (PER) in a pediatric population with refractory epilepsies. PATIENTS AND METHODS: This nonsponsored, observational, retrospective survey was conducted through collaboration with multiple centers in Europe. The clinical course of the first pediatric patients treated in these centers with PER was documented with the help of a questionnaire completed by the treating physicians. Effectiveness and adverse effects were evaluated. The study population consisted of 58 patients (mean age, 10.5 years; range, 2-17 years), suffering from various refractory epilepsies, classified as focal epilepsy (n = 36), unclassified generalized epilepsy (n = 12), Lennox-Gastaut syndrome (n = 5), West syndrome (n = 3), and Dravet syndrome (n = 2). RESULTS: The response rate (≥ 50% seizure reduction) after the first 3 months of therapy was 31% (18/58 patients) in total. Complete seizure control was achieved in five patients (9% overall). Aggravation of seizures occurred in five cases (9%). The most frequently occurring adverse effects were reduced vigilance or fatigue (n = 16) and behavioral changes (n = 14). DISCUSSION: PER seems to be effective also in children and adolescents with pharmaco-refractory epilepsies. Tolerability was acceptable.

Phenotypic and functional assessment of two novel KCNQ2 gain-of-function variants Y141N and G239S and effects of amitriptyline treatment.

While loss-of-function (LoF) variants in KCNQ2 are associated with a spectrum of neonatal-onset epilepsies, gain-of-function (GoF) variants cause a more complex phenotype that precludes neonatal-onset epilepsy. In the present work, the clinical features of three patients carrying a de novo KCNQ2 Y141N (n â€‹= â€‹1) or G239S variant (n â€‹= â€‹2) respectively, are described. All three patients had a mild global developmental delay, with prominent language deficits, and strong activation of interictal epileptic activity during sleep. Epileptic seizures were not reported. The absence of neonatal seizures suggested a GoF effect and prompted functional testing of the variants. In vitro whole-cell patch-clamp electrophysiological experiments in Chinese Hamster Ovary cells transiently-transfected with the cDNAs encoding Kv7.2 subunits carrying the Y141N or G239S variants in homomeric or heteromeric configurations with Kv7.2 subunits, revealed that currents from channels incorporating mutant subunits displayed increased current densities and hyperpolarizing shifts of about 10 â€‹mV in activation gating; both these functional features are consistent with an in vitro GoF phenotype. The antidepressant drug amitriptyline induced a reversible and concentration-dependent inhibition of current carried by Kv7.2 Y141N and G239S mutant channels. Based on in vitro results, amitriptyline was prescribed in one patient (G239S), prompting a significant improvement in motor, verbal, social, sensory and adaptive behavior skillsduring the two-year-treatment period. Thus, our results suggest that KCNQ2 GoF variants Y141N and G239S cause a mild DD with prominent language deficits in the absence of neonatal seizures and that treatment with the Kv7 channel blocker amitriptyline might represent a potential targeted treatment for patients with KCNQ2 GoF variants.

Electroclinical features and long-term therapeutic response in patients with typical absence seizures.

OBJECTIVE: To characterize in detail the electroclinical features of typical absence seizures and elucidate whether EEG or semiology features, alone or in combination, can predict long-term therapeutic outcome. METHODS: We analysed video-EEG recordings from 213 typical absence seizures from 61 patients with idiopathic generalized epilepsy. We extracted semiological features, in addition to hallmark manifestations (motor/behavioural arrest, non-responsiveness), their location, timing and frequency. We evaluated the duration and frequency of generalized spike-wave discharges and the presence of polyspikes. We used a supervised machine-learning approach (random forest) to search for classifier features for long-term therapeutic outcome (>one year). RESULTS: Besides the hallmark manifestations, additional semiological features were identified in 87% of patients (75% of seizures). The most common additional semiological features were automatisms and eye blinking (observed in 45% and 41.5% of seizures, respectively). Automatisms were associated with longer seizure duration, and oral automatisms occurred earlier compared to limb automatisms (4.03 vs. 6.19 seconds; p=0.005). The mean duration of the ictal spike-wave discharges was nine seconds, and the median frequency was 3 Hz. Polyspikes occurred in 46 seizures (21.6%), in 19 patients (31%). Median follow-up was five years, and 73% of the patients were seizure-free at the end of the follow-up. None of the semiological features, alone or in combination, were predictors of therapeutic outcome. The only significant classifier was the presence of polyspikes, predicting a non-seizure-free outcome with an accuracy of 73% (95% CI: 70-77%), positive predictive value of 92% (95% CI: 84-98%) and negative predictive value of 60% (95% CI: 39-81%). SIGNIFICANCE: Semiological features, in addition to behavioural arrest and non-responsiveness, are common in typical absence seizures, but they do not predict long-term therapeutic outcome. The presence of polyspikes has a high positive predictive value for unfavourable therapeutic outcome, and their presence should therefore be included when reporting EEGs in patients with typical absence seizures.

A balanced translocation disrupts SYNGAP1 in a patient with intellectual disability, speech impairment, and epilepsy with myoclonic absences (EMA).

Epilepsy with myoclonic absences (EMA) is a rare form of generalized epilepsy occurring in childhood and is often difficult to treat. The underlying etiology of EMA is unknown in the majority of patients. Herein, we describe a patient with EMA and intellectual disability who carries a de novo balanced translocation: t(6;22)(p21.32;q11.21). We mapped the translocation breakpoints by fluorescence in situ hybridization (FISH), and the breakpoint at 6p21.32 was found to truncate the N-methyl-d-aspartate (NMDA)-receptor associated gene SYNGAP1. The breakpoint at 22q11.21 was within a highly variable region without known protein-coding genes. Mutations of SYNGAP1 are associated with nonsyndromal intellectual disability (NSID). Two-thirds of the patients described so far also have generalized epilepsy. This finding, together with our report, suggests that dysfunction of SYNGAP1 contributes to the development of generalized epilepsy, including EMA.

REM-sleep related hypermotor seizures: Video documentation and ictal source imaging.

INTRODUCTION: Rapid eye movement (REM) sleep has an inhibitory effect on epileptiform EEG discharges, and seizures occur extremely rarely in REM sleep. CASE STUDY: We present the case and video recordings of a 10-year-old boy, with sleep-related hypermotor seizures starting from REM sleep, identified from videoEEG recordings. The semiology comprised intense fear, tachycardia, tachypnea, followed by hypermotor manifestations. Further investigations included brain MRI and source localization of the EEG signals. Multiple antiepileptic drugs were tried, the patient obtaining a good control of the seizures in the last 2.5 years with eslicarbazepine. DISCUSSION AND CONCLUSION: The ictal EEG source imaging showed seizure onset in the anterior part of the right insula, with propagation to the orbitofrontal area, confirmed by the semiological sequence. Although rare, focal seizures can be triggered by REM sleep and our findings suggest that deficient maturation of brain areas involved in sleep modulation might induce insufficient desynchronization during REM sleep, thus allowing seizure emergence.

Pharmacoresponse in genetic generalized epilepsy: a genome-wide association study.

Aim: Pharmacoresistance is a major burden in epilepsy treatment. We aimed to identify genetic biomarkers in response to specific antiepileptic drugs (AEDs) in genetic generalized epilepsies (GGE). Materials & methods: We conducted a genome-wide association study (GWAS) of 3.3 million autosomal SNPs in 893 European subjects with GGE - responsive or nonresponsive to lamotrigine, levetiracetam and valproic acid. Results: Our GWAS of AED response revealed suggestive evidence for association at 29 genomic loci (p <10-5) but no significant association reflecting its limited power. The suggestive associations highlight candidate genes that are implicated in epileptogenesis and neurodevelopment. Conclusion: This first GWAS of AED response in GGE provides a comprehensive reference of SNP associations for hypothesis-driven candidate gene analyses in upcoming pharmacogenetic studies.

Ketogenic diet in the treatment of refractory continuous spikes and waves during slow sleep.

PURPOSE: To evaluate the effect of the ketogenic diet on electroclinical characteristics and cognitive function in children with continuous spikes and waves during slow sleep (CSWS). METHODS: Five children (four boys, one girl) aged between 8 and 13 years with CSWS refractory to conventional antiepileptic drugs (AEDs), including levetiracetam, and steroids were included. The prospective electroclinical assessment was performed prior to the ketogenic diet and once every 6 months post initiation during the 2-year period. All children underwent neuropsychological testing prior to the ketogenic diet and four of the children again 12 months after the diet's introduction. In case 4 the testing has been performed after 7 months and the diet was withdrawn after 9 months because of the lack of efficacy and the parent's wishes. In two patients the cognitive functions were also evaluated after 24 months since the diet's initiation. During the period on the ketogenic diet the concomitant AED treatment was unchanged. RESULTS: Electrographic evaluation after 24 months on the ketogenic diet showed CSWS resolution in one patient, mild decrease of the spike-wave index in one, and lack of response in three patients. The ketogenic diet did not influence the neuropsychological outcome, and intelligence quotient (IQ) scores remained low at the end of the follow-up period. However, in two patients an improvement in attention and behavior was demonstrated. DISCUSSION: This is the first study evaluating the efficacy of the ketogenic diet in children with CSWS. Five presented cases were refractory to AEDs and steroids. Only one case responded with complete CSWS disappearance; in one the effect of the ketogenic diet was partial and intermittent, whereas in three patients no response has been observed. These results show that the ketogenic diet did not appear to influence the neuropsychological outcome; however, the absence of a control group makes it impossible to conclude with certainty.

Current treatment options for Encephalopathy related to Status Epilepticus during slow Sleep.

The major goal of therapy in patients with Encephalopathy related to Status Epilepticus during slow Sleep (ESES) is to prevent or reduce associated cognitive deficits. Whether or not the EEG pattern of ESES should be completely suppressed to improve cognition is unknown. In clinical practice, there are two major challenges: to establish the optimal treatment strategy in patients with ESES, and to identify the patients who will benefit most from therapy, including atypical cases. Here, we provide a comprehensive overview of the current literature on treatment efficacy in patients with ESES.