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Background Focal cortical dysplasias (FCD) are a frequent cause of drug-resistant epilepsy in children but are often undetected on structural magnetic resonance imaging (MRI). We aimed to measure and validate the variation of resting state functional MRI (rs-fMRI) blood oxygenation level dependent (BOLD) metrics in surgically proven FCDs in children, to assess the potential yield for detecting and understanding these lesions. Methods We prospectively included pediatric patients with surgically proven FCD with inconclusive structural MRI and healthy controls, who underwent a ten-minute rs-fMRI acquired at 3T. Rs-fMRI data was pre-processed and maps of values of regional homogeneity (ReHo), degree centrality (DC), amplitude of low frequency fluctuations (ALFF) and fractional ALFF (fALFF) were calculated. The variations of BOLD metrics within the to-be-resected areas were analyzed visually, and quantitatively using lateralization indices. BOLD metrics variations were also analyzed in fluorodeoxyglucose-positron emission tomography (FDG-PET) hypometabolic areas. Results We included 7 patients (range: 3–15 years) and 6 aged-matched controls (range: 6–17 years). ReHo lateralization indices were positive in the to-be-resected areas in 4/7 patients, and in 6/7 patients in the additional PET hypometabolic areas. These indices were significantly higher compared to controls in 3/7 and 4/7 patients, respectively. Visual analysis revealed a good spatial correlation between high ReHo areas and MRI structural abnormalities (when present) or PET hypometabolic areas. No consistent variation was seen using DC, ALFF, or fALFF. Conclusion Resting-state fMRI metrics, noticeably increase in ReHo, may have potential to help detect MRI-negative FCDs in combination with other morphological and functional techniques, used in clinical practice and epilepsy-surgery screening.

Epilepsy is one of the main symptoms affecting the lives of individuals with tuberous sclerosis complex (TSC), causing a high rate of morbidity. Individuals with TSC can present with various types of seizures, epilepsies, and epilepsy syndromes that can coexist or appear in relation to age. Focal epilepsy is the most frequent epilepsy type with two developmental and epileptic encephalopathies: infantile spasms syndrome and Lennox–Gastaut syndrome. Active screening and early management of epilepsy is recommended in individuals with TSC to limit its consequences and its impact on quality of life, cognitive outcome and the economic burden of the disease. The progress in the knowledge of the mechanisms underlying epilepsy in TSC has paved the way for new concepts in the management of epilepsy related to TSC. In addition, we are moving from traditional “reactive” and therapeutic choices with current antiseizure medications used after the onset of seizures, to a proactive approach, aimed at predicting and preventing epileptogenesis and the onset of epilepsy with vigabatrin, and to personalized treatments with mechanistic therapies, namely mechanistic/mammalian target of rapamycin inhibitors. Indeed, epilepsy linked to TSC is one of the only epilepsies for which a predictive and preventive approach can delay seizure onset and improve seizure response. However, the efficacy of such interventions on long-term cognitive and psychiatric outcomes is still under investigation.

Many early-onset epilepsies present as developmental and epileptic encephalopathy associated with refractory seizures, altered psychomotor development, and disorganized interictal cortical activity. Abnormal upregulation of specific N-methyl-d-aspartate receptor (NMDA-R) subunits is being disentangled as one of the mechanisms of severe early-onset epilepsies. In tuberous sclerosis complex (TSC), upregulation of the GluN2C subunit of the NMDA-R with slow deactivation kinetic results in increased neuronal excitation and synchronization.Starting from an available GluN2C/D antagonist, NMDA-R-modulating compounds were developed and screened using a patch clamp on neuronal culture to select those with the strongest inhibitory effect on glutamatergic NMDA currents. For these selected compounds, blood pharmacokinetics and passage through the blood-brain barrier were studied. We tested the effect of the most promising compounds on epileptic activity in Tsc1Using a double-electrode voltage clamp on isolated NMDA currents, we identified the most prominent antagonists of the GluN2C subunit with no effect on GluN2A as a means of preventing side effects. The best compound passing through the blood-brain barrier was selected. Applied in vivo in six Tsc1Subunit-selective inhibition is a valuable target for developing drugs for severe epilepsies resulting from an upregulation of NMDA-R subunit-mediated transmission.

Ethosuximide, the first-line therapy for childhood absence epilepsy, is currently formulated as a syrup (Zarontin®, Pfizer) with a bitter taste and high sugar content, poorly adapted to children, and a ketogenic diet. The collaborative European FP7 project KIEKIDS aimed at developing an innovative sugar-free, tasteless formulation convenient for pediatric use. This dual Phase-I study evaluated two granule formulations based on lipid multiparticulate (LMP) technology. Two panels of 6 healthy adult volunteers underwent a randomized, placebo-controlled, partly blinded, 3-way cross-over trial, comparing ethosuximide granules A or B with placebo granules and syrup at single 10 mg/kg doses. Corresponding plasma pharmacokinetic profiles of ethosuximide were compared, along with palatability, safety, and tolerability. The LMP granule A proved suboptimal due to bitterness and adherence to beaker walls, while the optimized granule B revealed excellent palatability, similar to placebo granules, and low adherence to glass. The relative bioavailability of granules A versus syrup, based on dose-normalized C max and AUC 0-∞ was 93.7% [90% CI: 76.3-115.1] and 96.1% [91.0-101.5], respectively. For granules B it was 87.6% [81.6-94.0] and 92.5% [88.5-96.6], respectively, with slightly delayed t max of 0.75 h [0.5-4.05] compared to syrup 0.5 h [0.3-0.8]. Tolerability visual analog scales revealed a trend for statistically non-significant improvement versus syrup at peak (30 min) for transient dizziness (both granules), fatigue (granules A), and anxiety (granules B). The innovative ethosuximide granule formulation B achieves a suitable profile for pediatric use, being sugar-free, tasteless, bioequivalent, and well-tolerated while enabling precise adjustment to body weight.

Stiripentol is an orphan drug approved for the treatment of seizures associated with Dravet syndrome (since 2007 in Europe). Therapeutic options recently grew in this rare and severe early-onset epilepsy with the approval of stiripentol and cannabidiol in 2018 in the US and the positive trials just completed with fenfluramine. Areas covered: First, the short-term efficacy of stiripentol as adjunctive therapy to clobazam and valproate, which was discovered by serendipity thanks to a basket study and then confirmed in 1998 despite the small number of samples in phase III trials. Second, the further observational series worldwide, which showed sustained efficacy and satisfactory tolerability for up to 20 year exposure. Third, why it took more than 20 years for stiripentol be approved in a number of countries despite these extensive data: drug-drug interactions between stiripentol and comedication will be addressed, as well as the experimental and pharmacogenetic data which support the anticonvulsant effect of stiripentol per se. Expert opinion: Considering current and future competitors (cannabidiol and fenfluramine), efficacy seems lower for cannabidiol and seizure freedom seems occasionally be obtained with fenfluramine. Additionally, stiripentol could be especially useful in two critical conditions of the disease, very young age (2 years) and convulsive status epilepticus.

Epilepsy is one of the main symptoms affecting the lives of individuals with tuberous sclerosis complex (TSC), causing a high rate of morbidity. Individuals with TSC can present with various types of seizures, epilepsies, and epilepsy syndromes that can coexist or appear in relation to age. Focal epilepsy is the most frequent epilepsy type with two developmental and epileptic encephalopathies: infantile spasms syndrome and Lennox-Gastaut syndrome. Active screening and early management of epilepsy is recommended in individuals with TSC to limit its consequences and its impact on quality of life, cognitive outcome and the economic burden of the disease. The progress in the knowledge of the mechanisms underlying epilepsy in TSC has paved the way for new concepts in the management of epilepsy related to TSC. In addition, we are moving from traditional "reactive" and therapeutic choices with current antiseizure medications used after the onset of seizures, to a proactive approach, aimed at predicting and preventing epileptogenesis and the onset of epilepsy with vigabatrin, and to personalized treatments with mechanistic therapies, namely mechanistic/mammalian target of rapamycin inhibitors. Indeed, epilepsy linked to TSC is one of the only epilepsies for which a predictive and preventive approach can delay seizure onset and improve seizure response. However, the efficacy of such interventions on long-term cognitive and psychiatric outcomes is still under investigation.

Protocadherin 19 (PCDH19) mutations have been identified in epilepsy in females with mental retardation as well as patients with a "Dravet-like" phenotype. We aimed to elucidate the electroclinical phenotype associated with PCDH19 mutation, which is currently difficult to identify at onset leading to a delay in diagnosis. We retrospectively reviewed clinical and EEG data for 13 consecutive patients with PCDH19 mutations or deletions diagnosed at our centers from 2009 to 2011, and followed these patients into adolescence and adulthood. We identified a specific temporal sequence of electroclinical manifestations, identified as three main stages. During the first two years of life, previously healthy girls presented with clusters of afebrile focal seizures. Early seizures were recorded on video-EEG in 10/13 patients, and were focal (n=8) with temporo-occipital and frontal onset. Three patients with strictly stereotyped focal seizures underwent a pre-surgical work-up. Two patients started with generalized seizures, one presenting with early-onset atypical absences and the other generalized tonic-clonic seizures. During the course of the disease, from two to 10 years, seizures became fever-sensitive and continued to recur in clusters, although these were less frequent. Seizures were mainly described by eyewitnesses as generalized tonic-clonic, even though three of five seizures, recorded on EEG, showed a focal onset with fast bilateral spread. Atypical absences and fever-induced tonic-clonic seizures remained frequent in only one patient until the age of 16 years. No specific treatment or combination appeared to be more effective over another. Various degrees of cognitive or behavioural impairment were reported for all patients, but it was in the second decade that behavioural disturbances prevailed with hetero-aggressiveness and behaviour associated with frontal lobe abnormalities leading to psychosis in two. Early recognition of the above features should improve early diagnosis and long-term management of patients with epilepsy and PCDH19 mutations.

Vigabatrin is an antiepileptic drug indicated as monotherapy in infantile spasms. However, the pharmacokinetic profile of this compound in infants and young children is still poorly understood, as is the minimal effective dose, critical information given the risk of exposure-related retinal toxicity with vigabatrin. A reasonable approach to determining this minimal dose would be to identify the lowest dose providing a low risk of exposure overlap with the 36-mg/kg dose, which is the highest dose associated with an increased risk for treatment failure, based on randomized dose-ranging data. A population pharmacokinetic model was consequently developed from 28 children (aged 0.4-5.7 years) for the active S(+)-enantiomer, using Monolix software. In parallel, a population model was developed from published adult data and scaled to children using theoretical allometry and maturation of the renal function. A one-compartment model with zero-order absorption and first-order elimination described the pediatric data. Mean population estimates (percentage interindividual variability) for the apparent clearance, apparent distribution volume, and absorption duration were 2.36 L/h (24.5%), 17 L (38%), and 0.682 hours, respectively. Apparent clearance and apparent distribution volume were related to body weight by empirical allometric equations. Monte Carlo simulations evidenced that a daily dose of 80 mg/kg should minimize exposure overlap with the 36-mg/kg dose. Similar results were obtained for the adult model scaled to children. Consequently, a minimal effective dose of 80 mg/kg/day could be considered for patients with infantile spasms.

Objective To evaluate continuing stiripentol treatment in adulthood in Dravet syndrome (DS). Method Longitudinal data were collected from the last visit prior to age 15 years (V15 y ) to the last visit in adulthood (Vadult ) in the 40 DS patients (32 typical, eight atypical) of a French historical cohort (Paris) of subjects who continued stiripentol from childhood or adolescence to adulthood. Results At Vadult (18-40 years, median = 23 years), all the patients were still receiving stiripentol (exposure = 3-24 years, median = 18 years), associated with clobazam (40/40), valproate (39/40), and topiramate (21/40). Between V15 y and Vadult , stiripentol was interrupted in five patients (two for adverse events) but reintroduced following seizure aggravation. Loss of appetite affected 15 of 40 patients but resolved after reducing the dose of stiripentol or valproate; no other new stiripentol-related adverse events were reported. Mean stiripentol dose was progressively decreased from 39 to 25 mg/kg/d (P = 0.0002), whereas clobazam (0.27 mg/kg/d) and valproate (14 mg/kg/d) remained stable. At Vadult , 37 of 40 patients still had generalized tonic-clonic seizures, but none still had status epilepticus (vs three at V15 y ) and only one had myoclonia. During adulthood, generalized tonic-clonic seizure frequency and duration continued to decrease (P = 0.02, P = 0.008) and 10 patients experienced seizure-free periods ≥ 1 years (up to 5 years). All patients already had intellectual disability at V15 y , but retardation was more severe at Vadult (P = 0.03). Furthermore, neurological/gait condition had declined (two patients became bedridden) and behavior had worsened (P 15 years) and the DS patients treated from adult age or stiripentol-naive subjects reported in the literature. Significance The efficacy and safety of the stiripentol/valproate/clobazam combination started at pediatric age are maintained at very long term during adulthood. Such prolonged stiripentol therapy tends to positively impact the late prognosis of epilepsy, especially when initiated before adolescence.

Background Early onset epileptic encephalopathies are rare paediatric diseases, with seizures resistant to drugs and impacting development of cognitive and motor functions. Many of them show monogenic aetiology and engineered animal models are crucial to understand the underlying mechanisms and propose treatment trials. These models have mostly been explored in vitro or in vivo under anaesthesia. This may affect the occurrence of epileptic activities and their clinical expression. These study conditions perturb social skills and are limited in time. New method We developed a technique using telemetric recordings by means of the Data Science International (DSI) mouse transmitter to study long lasting electro-cortical activity in freely moving mice younger than three weeks, trying to minimally affect social interactions and development Results We describe how to implant telemetry EEG devices in mice aged P13 to P18, weighing 7–10 g, including the surgical procedure and the recovery phase. Normal EEG data and epileptic activities can be recorded up to 2 months after implantation in normally behaving animals. Comparisons with existing methods Electrocorticographic studies of mouse pups are rare, and few devices allow EEG recording at these ages. Here, the telemetry devices used for adult mice were implanted in mouse pups. The surgical procedure was well tolerated. An adapted recovery protocol allowed EEG recording during the period of interest. Conclusion This technique was developed with currently used devices to enable better understanding of the pathophysiology of epileptic encephalopathies, chronic recording of seizures and helping the development of new therapies using chronic trials in the young animal.

Objectives Little is known about off-label use and manipulations to achieve the prescribed dose of antiepileptic drugs (AEDs) in outpatient prescriptions. This study aimed to evaluate this practice in a tertiary center for child epilepsy. Methods We reviewed off-label use and manipulations of AEDs delivered to the outpatient's epilepsy clinic. Multivariate logistic regressions were used to determine the factors associated with off-label and manipulated uses. Results Five hundred eleven consultations generated 897 AED deliveries (1.75/consultation). Off-label use involved 182 (20.3%) of prescribed AEDs. Factors associated with off-label use were polytherapy and new AEDs while increase of age and nondevelopmental and structural–metabolic etiologies have a protective effect. Among the 1725 doses of AEDs prescribed per day, 33.5% generated manipulations (n = 582): 40% inadequate (n = 237) and 60% adequate (203 syrups, 112 scored tablets, 30 drops medicine). Polytherapy (p Conclusion Off-label use and manipulations of AEDs remain an important problem in home care of children with epilepsy. This is mainly a concern for the most vulnerable groups, i.e., young patients, patients undergoing polytherapy, and patients with developmental and epileptic encephalopathy (DEE). International initiatives have been launched to improve the availability of labeled and adapted drugs in this population.

The original version of this article has added numbers in the text which are unnecessary. Correct line should be: “We also performed PET/MRI based surgical resections in an increasing number of MRI negative/ doubtful cases with favourable outcome.”

Background Dravet Syndrome (DS) is a rare developmental and epileptic encephalopathy characterized by multiple seizures, frequently prolonged and treatment refractory, with significant developmental disabilities and behavioral and psychiatric disorders. Patients with DS require intensive support and supervision from a caregiver, impacting significantly on both patients' and caregivers' lives. This study aimed to identify core concepts to measure the impact on both patients and caregivers in future DS clinical trials. Methods Qualitative concept elicitation interviews were conducted with caregivers and healthcare professionals involved in caring for children with DS (aged 2–18 years) in France to identify important concepts related to the global impact of DS. Interviews explored a range of concepts, including triggers, symptoms, impacts, and coping strategies, from which a conceptual model was developed. A Delphi consensus panel with eight international clinical experts aimed to identify important and relevant endpoints. Results Seizure was the most commonly reported symptom with DS further impacting children's cognitive and behavioral functioning. Caregivers identified impact concepts not reported by healthcare professionals. Both groups described additional impacts on wider family members and home modifications. Clinical experts agreed on the inclusion of five patient- and caregiver-relevant concepts for measurement in future DS clinical trials in a composite endpoint. The five concepts for inclusion were; seizures, expressive communication of the child, receptive communication of the child, impact on daily activities, and social functioning of the caregiver. Conclusions This study showed the wider potential impact of DS to extend beyond that of seizures, demonstrating that there is a need for additional patient- and caregiver-relevant concepts to be measured in clinical trials to fully identify the value of therapeutic interventions.

International audience; AimsOxcarbazepine is an antiepileptic drug with an activity mostly due to its monohydroxy derivative metabolite (MHD). A parent-metabolite population pharmacokinetic model in children was developed to evaluate the consistency between the recommended paediatric doses and the reference range for trough concentration (Ctrough) of MHD (3–35 mg l–1).MethodsA total of 279 plasma samples were obtained from 31 epileptic children (age 2–12 years) after a single dose of oxcarbazepine. Concentration-time data were analysed with Monolix 4.3.2. The probability to obtain Ctrough between 3–35 mg l–1 was determined by Monte Carlo simulations for doses ranging from 10 to 90 mg kg–1 day–1.ResultsA parent-metabolite model with two compartments for oxcarbazepine and one compartment for MHD best described the data. Typical values for oxcarbazepine clearance, central and peripheral distribution volume and distribution clearance were 140 l h–1 70 kg–1, 337 l 70 kg–1, 60.7 l and 62.5 l h–1, respectively. Typical values for MHD clearance and distribution volume were 4.11 l h–1 70 kg–1 and 54.8 l 70 kg–1 respectively. Clearances and distribution volumes of oxcarbazepine and MHD were related to body weight via empirical allometric models. Enzyme-inducing antiepileptic drugs (EIAEDs) increased MHD clearance by 29.3%. Fifty-kg children without EIAEDs may need 20–30 mg kg–1 day–1 instead of the recommended target maintenance dose (30–45 mg kg–1 day–1) to obtain Ctrough within the reference range. By contrast, 10-kg children with EIAEDs would need 90 mg kg–1 day–1 instead of the maximum recommended dose of 60 mg kg–1 day–1.ConclusionThis population pharmacokinetic model of oxcarbazepine supports current dose recommendations, except for 10-kg children with concomitant EIAEDs and 50-kg children without EIAEDs.

Objectives To describe the semiology and EEG characteristics of the age-related pattern of sleep/nocturnal (S/N) seizures in patients with Dravet Syndrome (DS). Methods We retrospectively analysed the clinical and EEG data of DS patients followed at our reference centre for Rare Epilepsies. We included patients aged two years and older who fulfilled clinical and EEG criteria of DS (ILAE 1989). Genetic testing for SCN1A was done in all, followed by PCDH19 if this was negative. Patients showing a genetic abnormality in PCDH19 were excluded. Of 73 DS patients followed at our centre, 26 (15 males and 11 females), called the S/N group, experienced a switch in the circadian rhythm of seizures, from mainly awake/diurnal to mainly S/N seizures. We retrospectively analysed their clinical, EEG and genetic data. We have compared them to a second group of 7 patients (4 males and 3 females), aged more than 11 years, the non-S/N group, who did not develop S/N seizures. Results We observed a pattern of S/N seizures concomitant with a decrease of awake seizures between 4 and 11 years (median 6 years 6 months). S/N seizures were brief but often occurred in clusters of 2–15 per night. Seizures were mostly focal (26) with frontal-central onset (25) and tonic or tonic-vibratory in semiology. S/N seizure clusters were difficult to control despite many AEDs trials. Benzodiazepines reduced seizure recurrence within a cluster in some patients. While no significant differences were found between groups regarding clinical features, the presence of frontal and central anomalies on wake and sleep EEG was significantly associated with the presence of the S/N pattern. Conclusions Patients with DS often develop a characteristic clinical and EEG pattern with S/N tonic and tonic clonic seizures that is often underdiagnosed. Seizure semiology and EEG pattern differ from LGS but may worsen the quality of sleep of such patients and their families. The possible role of this pattern in SUDEP occurring mainly during sleep and at the same age should be further explored. Current AEDs have limited efficacy and specific drug trials should be proposed.

The aim of this study was to assess outcome and seizure response to treatment with stiripentol (STP) associated to valproate (VPA) and clobazam (CLB), which we have used in our center since the 1990s, in patients with Dravet syndrome (DS).We performed a cross-sectional study of all DS patients with SCN1A mutations who had at least one visit to our center in 2013. A total of 54 patients were included (32 males, 22 females), whose ages ranged from 2.5 to 22 years.Seizure onset ranged from 2 to 9 months (mean 5 months). Treatment started at a mean age of 7 months with valproate (VPA) as first therapy in 83% of patients. STP was prescribed in 96% at an average age of 20 months. At last follow-up (up to 22 years, median 8 years), 96% were still receiving STP, with VPA and clobazam (CLB) in 91%. Additional therapies were prescribed in 72% of patients. Most patients (96%) continued to have clonic or tonic-clonic seizures but they were brief (5min, with last status epilepticus (SE) episode being before 4 years of age). Seizures occurred weekly (3/month) in 38% of patients, monthly (1-3/month) in 40%, and yearly in the remaining patients. None presented with daily seizures. Seizure frequency at last visit was related to the age of treatment initiation, the age of last SE, and SCN1A mutation type.Triple therapy with STP, VPA, and CLB was maintained long-term by 96% of this large DS cohort because the reduced frequency and severity of seizures STP provided when added to CLB and VPA was durable. Nevertheless, only a few patients achieved seizure freedom and persisting seizures remains a concern in the majority of patients.

Objective: Since SCN1A is expressed in the motor neuron initial segment, we explored whether motor neuron dysfunction could contribute to gait disturbance and orthopedic misalignment in patients with Dravet syndrome due to SCN1A mutations. Methods: We assessed 12 consecutive patients who presented to our institution between January and March 2013. All of them were older than 2 years and were positive for the SCN1A mutation. We performed nerve conduction velocity studies and needle EMG recordings. Results: We included 4 females and 8 males aged 2 to 17 years (median 7.5 years). All 12 patients showed gait disturbance regardless of age. Tendon reflexes were decreased in 4 of 12 patients. None presented cerebellar signs such as tremor, dysmetria, or adiadochokinesia. Nerve conduction study was normal or nearly normal in all patients, but EMG showed features of chronic denervation. Motor neuropathy/neuronopathy was definite in 7 patients and probable in 3. Conclusions: SCN1A mutations may alter axonal function, causing motor neuropathy/neuronopathy. This may contribute to gait disturbance and orthopedic misalignment, which is characteristic of patients with Dravet syndrome.

The aim of this study was to investigate the age-related changes in resting-state neurometabolic connectivity from childhood to adulthood (6-50 years old). Fifty-four healthy adult subjects and twenty-three pseudo-healthy children underwent [(18) F]-fluorodeoxyglucose positron emission tomography at rest. Using statistical parametric mapping (SPM8), age and age squared were first used as covariate of interest to identify linear and non-linear age effects on the regional distribution of glucose metabolism throughout the brain. Then, by selecting voxels of interest (VOI) within the regions showing significant age-related metabolic changes, a psychophysiological interaction (PPI) analysis was used to search for age-induced changes in the contribution of VOIs to the metabolic activity in other brain areas. Significant linear or non-linear age-related changes in regional glucose metabolism were found in prefrontal cortices (DMPFC/ACC), cerebellar lobules, and thalamo-hippocampal areas bilaterally. Decreases were found in the contribution of thalamic, hippocampal, and cerebellar regions to DMPFC/ACC metabolic activity as well as in the contribution of hippocampi to preSMA and right IFG metabolic activities. Increases were found in the contribution of the right hippocampus to insular cortex and of the cerebellar lobule IX to superior parietal cortex metabolic activities. This study evidences significant linear or non-linear age-related changes in regional glucose metabolism of mesial prefrontal, thalamic, mesiotemporal, and cerebellar areas, associated with significant modifications in neurometabolic connectivity involving fronto-thalamic, fronto-hippocampal, and fronto-cerebellar networks. These changes in functional brain integration likely represent a metabolic correlate of age-dependent effects on sensory, motor, and high-level cognitive functional networks. Hum Brain Mapp 37:3017-3030, 2016. © 2016 Wiley Periodicals, Inc.

Stiripentol and vigabatrin are the two anticonvulsant drugs currently approved in severe infantile-onset epilepsies, respectively Dravet syndrome and infantile spasms.For both, the indication was discovered by chance thanks to an exploratory study. Both demonstrated indisputable efficacy through randomized-controlled trials. Stiripentol as adjunctive therapy to clobazam and valproate performed better than placebo, and vigabatrin as first-line monotherapy better than the reference steroid therapy in spasms due to tuberous sclerosis. At one-year treatment vigabatrin and steroids were equally efficient in the other etiologies of spasms. However, it took more than 20 years for both drugs to be approved world-wide.Stiripentol suffered from pharmacokinetic potentiation of clobazam, thus raising the question whether it was efficient per se. Finally, animal models and pharmacogenetic data on CYP2C19 confirmed its specific anticonvulsant effect. Stiripentol (in comedication with clobazam and valproate) is therefore to be recommended for Dravet patients. Vigabatrin was found to have a frequent and irreversible retinal toxicity, which required an alternative visual testing to be detected in young children. Today the benefit/risk ratio of vigabatrin as first-line is considered to be positive in infantile spasms, given the severity of this epilepsy and the lack of a safer alternative therapy.

Vigabatrin is indicated as adjunctive therapy for refractory focal seizures. For children, European recommendations indicate maintenance doses varying from 30 to 100 mg/kg/day for this indication. Since cumulated dose was associated with retinal toxicity, it is essential to administrate the lowest effective dose to patients. This work was conducted with the purpose to determine the pediatric doses of vigabatrin that allow a similar exposure than effective doses in adults (2–3 g/day) through a pharmacokinetic (PK) study, using both pediatric and adult data. For this study, we focused on the active S(+) enantiomer of vigabatrin. First, the adult effective exposition range of vigabatrin-S was determined from an adult PK model. Then, this same model was scaled to the pediatric population using allometry and maturation principles to account for growth and development. The ability of the model to predict pediatric data was assessed by comparing population predictions with observed pediatric data. Finally, the extrapolated pediatric model was used to simulate pediatric expositions which were compared to the adult exposition range (36.5–77.9 mg.h/L). From those simulations, we determined that, for children aged between 3 months and 18 years, doses between 40 and 50 mg/kg/day allow vigabatrin-S expositions similar to those found in adults at the recommended posology. We proposed those doses as optimal maintenance doses that may be increased, if necessary, by slow titration.

To assess the relevance and generalizability across countries of concepts of the impact of Dravet syndrome beyond seizures, as recognized by families.Caregivers of children with Dravet syndrome in four countries (Australia [n=8]; USA, UK, and Italy [all n=4]) participated in 1-hour qualitative telephone interviews, identifying key Dravet syndrome concepts. Interviews were recorded, transcribed, and, where necessary, translated into English for thematic analysis. Conceptual saturation was assessed and findings compared to the previously developed French conceptual disease model.The most common seizure types reported by caregivers were tonic-clonic, absence, or focal-impaired awareness (localized/partial). Fever and physical activity were the most commonly reported triggers. Patient-relevant impacts included impairment in cognition, motor skills, communication, social skills, and behavioural functioning. Caregivers consistently reported negative social, physical, and family impacts. Concepts identified in the interviews showed similarity with the French conceptual model. Minor differences between countries are likely to reflect variations in health care systems.Findings in Italy, Australia, UK, and USA confirm that the key impacts of Dravet syndrome on children and caregivers identified in France are generalizable across countries. Key symptom and impact concepts relevant to children and parents should be targeted as critical outcomes in new therapy evaluations.Relevance of the impact of Dravet syndrome on children and caregivers was confirmed across countries. Patient and caregiver-relevant Dravet syndrome impacts contribute to poorer health-related quality of life. Indirect seizure impacts were reported to be as important as direct impacts. Country-specific differences in concepts probably reflect differences in health care systems.PERCEPCIÓN DEL IMPACTO DEL SÍNDROME DE DRAVET EN NIÑOS Y CUIDADORES EN MÚLTIPLES PAÍSES: UNA OBSERVACIÓN MÁS ALLÁ DE LAS CONVULSIONES: OBJETIVO: Evaluar la relevancia y la generalización de los conceptos del impacto del síndrome de Dravet, más allá de las convulsiones, en distintos países y como lo reconocen las familias. METODO: Cuidadores de niños con síndrome de Dravet en cuatro países (Australia [n=8], EEUU, Reino Unido e Italia [todos n=4]) participaron de una entrevista cualitativa de una hora de duración, identificando conceptos claves en el síndrome de Dravet. Las entrevistas fueron grabadas, transcriptas, y si era necesario, traducidas al inglés para análisis temáticos. Se evaluó la saturación conceptual y los resultados se compararon con el modelo conceptual de enfermedad francés, desarrollado previamente. RESULTADOS: Los tipos más comunes de convulsión reportados por los cuidadores fueron la tónico-clónica, las ausencias o las focales con alteración de la conciencia (localizadas/parciales). La fiebre y las actividades físicas fueron los desencadenantes más comúnmente reportados. Los impactos reportados en los pacientes fueron alteraciones en la cognición, habilidades motrices, comunicación, habilidades sociales y funcionamiento conductual. Los cuidadores informaron sistemáticamente sobre los impactos negativos a nivel social, físico y familiar. Los conceptos identificados en las entrevistas mostraron similitud con el modelo conceptual francés. Es probable que las diferencias menores entre países reflejen variaciones en los sistemas de atención de salud. INTERPRETACIÓN: Los hallazgos en Italia, Australia, Reino Unido y EEUU confirman que las alteraciones claves del síndrome de Dravet en niños y cuidadores identificados en Francia son generalizables en todos los países. Los síntomas claves y las alteraciones relevantes para los niños y los padres deben ser considerados como objetivos críticos de evolución cuando se evalúan el diseño de nuevas terapias.PERCEPÇÃO DO IMPACTO DA SÍNDROME DE DRAVET EM CRIANÇAS E CUIDADORES EM MÚLTIPLOS PAÍSES: OLHANDO PARA ALÉM DAS CONVULSÕES: OBJETIVO: Avaliar a relevância e generalizabilidade entre países dos conceitos sobre o impacto da síndrome de Dravet para além das convulsões, com base no reconhecimento das famílias. MÉTODO: Cuidadores de crianças com síndrome de Dravet em quatro países (Australia [n=8]; EUA, Reino Unido, e Itália [all n=4]) participaram de entrevistas qualitativas por telefone com duração de 1 hora, identificando conceitos chave da síndrome de Dravet. As entrevistas foram gravadas, transcritas, e quando necessário, traduzidas para o inglês para análise temática. A saturação conceitual foi avaliada e os resultados comparados com o modelo conceitual francês da doença desenvolvido previamente. RESULTADOS: Os tipos mais comuns de convulsões reportados pelos cuidadores eram tônico-clônico, ausência, ou redução focal da consciência (localizada/parcial). Febre e atividade física foram os gatilhos mais comumente reportados. Os impactos relevantes para os pacientes incluíram deficiências na cognição, habilidades motoras, comunicação, habilidades sociais, e funcionamento comportamental. Os cuidadores reportaram impactos negativos sociais, físicos e familares. Os conceitos identificados nas entrevistas mostraram similaridades com o modelo conceitural francês. Diferenças pequenas entre países provavelmente refletem variações nos sistemas de cuidado à saúde. INTERPRETAÇÃO: Achados na Itália, Austrália, Reino unido e EUA confirmam que os impactos principais da síndrome de Dravet em crianças e cuidadores identificados na Franca são generalizáveis entre países. Os principais sintomas e conceitos de impacto relevantes para crianças e pais devem ser visados como desfechos críticos na avaliação de novas terapias.

International audience; Characteristic preterm EEG patterns of "Delta-brushes" (DBs) have been reported in the temporal cortex following auditory stimuli, but their spatio-temporal dynamics remains elusive. Using 32-electrode EEG recordings and co-registration of electrodes' position to 3D-MRI of age-matched neonates, we explored the cortical auditory-evoked responses (AERs) after 'click' stimuli in 30 healthy neonates aged 30-38 post-menstrual weeks (PMW). (1) We visually identified auditory-evoked DBs within AERs in all the babies between 30 and 33 PMW and a decreasing response rate afterwards. (2) The AERs showed an increase in EEG power from delta to gamma frequency bands over the middle and posterior temporal regions with higher values in quiet sleep and on the right. (3) Time-frequency and averaging analyses showed that the delta component of DBs, which negatively peaked around 550 and 750 ms over the middle and posterior temporal regions, respectively, was superimposed with fast (alpha-gamma) oscillations and corresponded to the late part of the cortical auditory-evoked potential (CAEP), a feature missed when using classical CAEP processing. As evoked DBs rate and AERs delta to alpha frequency power decreased until full term, auditory-evoked DBs are thus associated with the prenatal development of auditory processing and may suggest an early emerging hemispheric specialization.

The original version of this article has added numbers in the text which are unnecessary. Correct line should be: "We also performed PET/MRI based surgical resections in an increasing number of MRI negative/ doubtful cases with favourable outcome."

Recent experimental data suggest bumetanide as a possible therapeutic option in newborn infants with seizures after birth asphyxia. Because pharmacokinetic (PK) data are lacking in this population, who very often benefit from therapeutic cooling, which can modify the PK behavior of a drug, a PK study was conducted in term infants with seizures caused by hypoxic-ischemic encephalopathy. Fourteen infants were included, 13 of them being cooled. Forty-nine blood samples were available for the determination of the plasma concentration of bumetanide. Concentration-time data were analyzed by the use of a population approach performed with Monolix Software. Bumetanide was found to follow a 2-compartment model. The mean values were 0.063 L/h for clearance, 0.28 and 0.44 L for the central and peripheral distribution volumes, respectively, and 0.59 L/h for the distribution clearance. Birth body weight explained the interindividual variability of bumetanide clearance via an allometric model. No relationship was found between bumetanide exposure and its efficacy (reduction in seizure burden) or its toxicity (hearing loss). This study describes the first PK model of bumetanide in hypothermia-treated infants with seizures.

New non-invasive functional magnetic resonance imaging (fMRI) techniques are deeply changing the exploration of epileptic and functional networks in childhood epilepsies, as well as of the normally developing brain. In this review, we first briefly describe the fMRI methods and the specificity, advantages and limitations of fMRI protocols and studies in pediatric epi- lepsies. Current fMRI applications in pediatric epilepsies mostly refer to presurgical mapping that can be performed with motor, language or memory tasks, and allows to select patients, tailor resection and sometimes predict postoperative cognitive outcome. Functional connectivity studies are currently emerging from resting state fMRI acquisitions to assess the possible consequences of epileptic activity on the development of functional long distance networks. Future directions for research applications, espe- cially connectivity analysis, and new developments such as electroencephalography-fMRI, will lead to better comprehensive descriptions of functional brain networks in pediatric epilepsy.

The objective of this work was to develop a population pharmacokinetic model for a prolonged-release granule formulation of valproic acid (VPA) in children with epilepsy and to determine the doses providing a VPA trough concentration (Ctrough) within the target range (50–100 mg/L). Ninety-eight children (1–17.6 years, 325 plasma samples) were included in the study. The model was built with NONMEM 7.3. The probability to obtain Ctrough between 50 and 100 mg/L was determined by the Monte Carlo simulations for doses of 20, 30, 40, and 60 mg/kg/day and body weights between 10 and 70 kg. A one compartment model, with first-order absorption and flip-flop parameterization and linear elimination, but taking protein binding into account, was used to describe the data. Typical values for unbound VPA clearance and distribution volume were 6.24 L/h/70 kg and 130 L/h/70 kg respectively. Both parameters were related to body weight via allometric models. The highest probability to obtain a Ctrough within the target range for 10-kg children was obtained with a 40 mg/kg daily dose, whereas daily doses of 30 and 20 mg/kg were found appropriate for 20 to 30- and ≥ 40-kg children respectively. However, for these same doses, the exposure to unbound VPA could differ by 40%. If the present study supports the current dose recommendations of 20–30 mg/kg/day, except for children under 20 kg, who may need higher doses, it also highlights the need for further research on the pharmacokinetics/pharmacodynamic profile of unbound VPA.

The aim of this study was to describe the pharmacokinetics of stiripentol in children with Dravet syndrome and to determine the concentrations of stiripentol achieved in this population for the usual 25 mg/kg twice-daily dose. Thirty-five children with epilepsy were included in a prospective population pharmacokinetic study (using MONOLIX software). Four blood samples were drawn per patient. Stiripentol area under the plasma concentration–time curve (AUC) values and trough concentrations were simulated for 7000 theoretical children weighing between 10 and 70 kg for the 25 mg/kg twice-daily dose. The pharmacokinetics of stiripentol was described using a one-compartment model with zero-order absorption and first-order elimination. The apparent clearance (CL/F) and apparent volume of distribution (V d/F) of stiripentol were related to body weight by allometric equations. A dose-dependent non-linearity was also observed with an allometric model relating CL/F to the weight-normalised dose. Mean population estimates (% inter-individual variability) were 4.2 L/h (21%) for CL/F and 82 L (25%) for V d/F. The AUC of stiripentol increased by 300% when body weight increased from 10 to 70 kg. This population pharmacokinetic model of stiripentol in children with Dravet syndrome confirmed the dose-dependent non-linearity that has been evidenced in adults. It also supported that a 25 mg/kg twice-daily dose might lead to excessive exposure in children >30 kg, suggesting an eventual dose adjustment during adolescence. This study is part of the STIPOP study (EUDRACT number: 2007-001784-30).

The aim was to localize the interictal cerebral perfusion abnormalities of focal cortical dysplasia (FCD) in children with Arterial Spin Labeling MRI (ASL) in a retrospective study of nine consecutive children explored with multimodal investigation during interictal periods. We analyzed brain morphology with a 1.5T MRI and a dedicated protocol for epilepsy. Brain perfusion was quantified with pseudo continuous ASL. Brain metabolism was imaged with (18)FDG-PET in six patients. Microvessel histology was studied in five children who underwent epilepsy surgery with CD34 immunostaining on FCD and control samples. Localized decrease of cerebral blood flow (CBF) was found on visual analysis in all patients with ASL. It was co-localized with the structural MRI abnormalities in every case, with PET hypo-metabolism in 5/6 cases, and with histologically proven FCD type IIb in 5/5 cases (all seizure free after surgery). CBF was lower (Kruskal-Wallis test, p=0.001) in FCD than in normal cortex. The total count of CD34+ microvessels was similar in FCD and control cases, but microvasculature showed disorganized architecture. Interictal ASL is a non-invasive method that may help to localize the epileptogenic zone showing hypo-perfusion in FCD. Whether this finding could be generalized to MRI-negative FCD needs to be further studied.

Summary Contrary to the treatment concerns regarding drug compliance or pregnancy at transition to adulthood, those directly related to epilepsy remain poorly documented. As an initial step to answer this problem, we reviewed the controlled trials of antiepileptic drugs (AEDs) independently performed in adults and children for a given syndrome. Then we reviewed the longitudinal long-term course in the various epilepsy syndromes. Optimizing AED treatment at adulthood might be beneficial, even after many years of pharmacoresistance. Finally we retrospectively reviewed our personal series of 39 patients with specific pharmacoresistant epilepsy syndromes, who transferred from pediatric to adult care between 2005 and 2012. In 26 of the patients, AEDs were modified and, we reduced seizure frequency in 62% of them, including highly refractory patients. By contrast, AED changes in six controlled patients (for pregnancy anticipation or vigabatrin-related retinal toxicity) led to severe seizure relapse. Further studies are needed to elaborate guidelines in pharmacoresistant syndromes during transition and after transfer to adult care.

To develop a physiologically based pharmacokinetic model in adults and children for clobazam, its active metabolite norclobazam and stiripentol and to account for significant clinical interaction that has been reported when clobazam and stiripentol are co-administered. A PBPK model with ten compartments was developed. An in vitro-in vivo extrapolation technique was used to scale clearance in children for clobazam and norclobazam and clearance parameters for stiripentol were obtained from fitting. Other drug and system parameters were obtained from the literature. The tissue/blood partition coefficients adequately predict observed volume of distribution for clobazam and stiripentol. In a clinical study in children where clobazam was administered alone and co-administered with stiripentol, the predicted and observed minimum concentration at steady state (mean and 95% confidence interval) during clobazam monotherapy were 0.19 (0.05–0.49 mg/L) and 0.20 (0.17–0.23 mg/L), respectively, and predicted and observed norclobazam concentrations were 0.49 (0.16–1.38 mg/L) and 0.95 (0.91–0.99 mg/L), respectively. From an interaction study with stiripentol the predicted stiripentol concentration was 10.12 (2.51–39.36 mg/L) and the observed concentration was 10.0 (8.3–11.7 mg/L); the predicted clobazam concentration was 0.29 (0.07–1.05 mg/L) and the observed concentration was 0.31 (0.24–0.38 mg/L); and the predicted norclobazam concentration was 2.30 (0.45–5.53 mg/L) and the observed concentration was 4.32 (3.77–4.87 mg/L). The PBPK model adequately described observed data and the extent of interaction between clobazam/norclobazam and stiripentol.

Previous studies investigating cerebral metabolic changes associated with continuous spike-waves during sleep (CSWS) compared the metabolism of children with CSWS with that of healthy adults, precluding any assessment in brain areas showing physiologic age-related metabolic changes. Here, we investigated the metabolic and connectivity changes characterizing the acute phase of CSWS activity by comparing awake brain metabolism of children with CSWS with that of pediatric pseudo-controls. Positron emission tomography using [18F]-fluorodeoxyglucose (FDG-PET) was performed in 17 awake children with cryptogenic CSWS (5 girls, age: 5-11 years). Voxel-based analyses identified significant metabolic changes in CSWS patients compared with 18 pediatric pseudo-controls (12 girls, age: 6-11 years, non-CSWS focal cryptogenic epilepsy with normal FDG-PET). CSWS-induced changes in the contribution of brain areas displaying metabolic changes to the level of metabolic activity in other brain areas were investigated using pathophysiological interaction. Hypermetabolism in perisylvian regions bilaterally and hypometabolism in lateral and mesial prefrontal cortex, precuneus, posterior cingulate cortex and parahippocampal gyri characterized the acute phase of CSWS (p0.05 FWE). No change in thalamic metabolism was disclosed. Altered functional connectivity was found between hyper- and hypometabolic regions in CSWS patients compared with pediatric pseudo-controls. This study demonstrates hypometabolism in key nodes of the default mode network (DMN) in awake patients with CSWS, in relation with a possible phenomenon of sustained remote inhibition from the epileptic foci. This hypometabolism might account for some of the acquired cognitive or behavioral features of CSWS epileptic encephalopathies. This study failed to find any evidence of thalamic metabolic changes, which supports the primary involvement of the cortex in CSWS genesis.

The neural networks involved in language recovery following hemispherotomy of the dominant hemisphere after language acquisition in children remain poorly known. Twelve hemispherotomized children (mean age at surgery: 11.3years) with comparable post-operative neuropsychological patterns underwent multi-task language functional MRI. Three of them had recovered from an initial postoperative aphasia i.e., hemispherotomy was performed on the language-dominant hemisphere. Our main results revealed (1) perisylvian activations in all patients after either left or right hemispherotomy; (2) no differences in activations between groups regarding the side of hemispherotomy; (3) additional activations in pre-frontal (3/3) and hippocampal/parahippocampal and occipito-parietal (2/3) areas, when comparing language activation in each of the three subjects with hemispherotomy of the language-dominant hemisphere to the group of 9 non-dominant hemispherotomized patients. These neural networks support the stronger engagement of learning and memory during language recovery in a hemisphere that was not initially actively subserving language.

Abnormal reemergence of depolarizing GABAA current during postnatal brain maturation may play a major role in paediatric epilepsies, Dravet syndrome (DS) being among the most severe. To study the impact of depolarizing GABA onto distinct patterns of EEG activity, we extended a neural mass model as follows: one sub-population of pyramidal cells was added as well as two sub-populations of interacting interneurons, perisomatic-projecting interneurons (basket-like) with fast synaptic kinetics GABAA (fast, I1) and dendritic-projecting interneurons with slow synaptic kinetics GABAA (slow, I2). Basket-like cells were interconnected to reproduce mutual inhibition mechanisms (I1➔I1). The firing rate of interneurons was adapted to mimic the genetic alteration of voltage gated sodium channels found in DS patients, SCN1A(+/-). We implemented the "dynamic depolarizing GABAA" mediated post-synaptic potential in the model, as some studies reported that the chloride reversal potential can switch from negative to more positive value depending on interneuron activity. The "shunting inhibition" promoted by GABAA receptor activation was also implemented. We found that increasing the proportion of depolarizing GABAA mediated IPSP (I1➔I1 and I1➔P) only (i.e., other parameters left unchanged) was sufficient to sequentially switch the EEG activity from background to (1) interictal isolated polymorphic epileptic spikes, (2) fast onset activity, (3) seizure like activity and (4) seizure termination. The interictal and ictal EEG patterns observed in 4 DS patients were reproduced by the model via tuning the amount of depolarizing GABAA postsynaptic potential. Finally, we implemented the modes of action of benzodiazepines and stiripentol, two drugs recommended in DS. Both drugs blocked seizure-like activity, partially and dose-dependently when applied separately, completely and with a synergic effect when combined, as has been observed in DS patients. This computational modeling study constitutes an innovative approach to better define the role of depolarizing GABA in infantile onset epilepsy and opens the way for new therapeutic hypotheses, especially in Dravet syndrome.

The efficacy of stiripentol (STP) in Dravet Syndrome (DS) was discovered first in an exploratory study in pediatric pharmacoresistant epilepsies. This efficacy signal, used as a proof of concept, led to - two independent multicenter randomized, double-blind, placebo-controlled trials in DS patients: STICLO-France and STICLO-Italy. In adjunction to valproate and clobazam, STP demonstrated marked efficacy and these trials became the basis for the registration of STP as an orphan drug for DS. Although STP had previously shown antiepileptic activity, since it inhibits cytochromes P450, the increased plasma levels of clobazam (CLB), norclobazam (NCLB), and NCLB/CLB ratio reported in STICLO studies brought into question the activity of STP per se. Recent pharmacological studies demonstrated that (i) STP is a direct allosteric modulator of the GABA receptors at a site distinct from benzodiazepines; (ii) STP and CLB/NCLB act independently at GABA(A) receptors; (iii) their combination increases the maximum response beyond that of either drug alone. All these effects are independent of considerations of changes in metabolism. Some responders in STICLO studies failed to display any increase of plasmatic concentrations of NCLB/CLB ratio as STP could not inhibit CYP2C19 because of its inhibition by progabide or due to an inactivating CYP polymorphism. The responder rate proved to be in the same range whether the NCLB/CLB ratio increased or not. These analyses confirmed that the effects of STP cannot result from a simple pharmacokinetic interaction. We propose that the success of STP should serve as a model for AED development in rare pediatric epileptic syndromes.