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The lack of ideal measurement of treatment efficacy is a well acknowledged problem in the epilepsy community, both in clinical care and clinical trials. Whilst still the current gold-standard, self-reported seizure frequency significantly underestimates the true number of seizures and does not account for any other at least equally important outcome parameters, such as neurodevelopment and cognition. With the rise of disease modifying treatments, the need for more reliable endpoints in practice and clinical trials becomes more pressing. In this paper we assembled an expert panel to discuss the nature of these needs, current limitations, and obstacles based on a survey amongst these experts who were queried about the most important issues regarding the use of electroencephalography (EEG) parameters as endpoints in clinical drug and device development.A structured survey was sent to a group of experts in the design and conduct of epilepsy trials in adults and children. This was followed by a virtual in-person meeting discussing the results of the trial and identifying a list of most important issues.Six clinical trialists and 5 individuals from pharmaceutical companies returned the survey containing 14 questions, and 8 clinical trialists and 10 pharma-representatives attended the meeting. Three main issues were identified (1) lack of accuracy of seizure diaries due to nocturnal seizures, subtle motor seizures, impairment of consciousness and lack of awareness of the seizure by the patient (2) inter-rater variability of EEG assessment (3) lack of standardization regarding definition(s) of seizures (clinical and electrographic), EEG recording methods and EEG data management. Recommended solutions included (1) validation of EEG parameters as biomarkers and use of wearables (2) development of a manual that describes EEG rating criteria, protocol for validation by 1 central reader and use of a resolution of disagreements reporting template (3) standardization of EEG recording, data management and reporting.Current developments in research and technology seem promising to advance the use of EEG parameters as potential endpoints and offer partial solutions to the current needs. However, continuous, focused and collaborative efforts of all stakeholders (academia, industry and regulatory agencies) are needed to formulate guidelines, validate emerging technologies and approve them for use in trials. It is the intent of this opinion "position paper" to stimulate those efforts.

Purpose Sturge-Weber syndrome (SWS) is a neurocutaneous disorder characterized by a facial port-wine stain, a glaucoma, and a leptomeningeal angioma. Epilepsy occurs in more than 75% of affected children, and seizures occurring in the first year of life are associated with a poor neurological prognosis. The aim of this study was to identify possible predictive markers of epilepsy on electroencephalogram (EEG) performed prior to seizure onset in children with SWS. Methods This study included children with a diagnosis of SWS who had an EEG performed prior to seizure onset. Patients who did not develop epilepsy had a minimum follow-up of 3-years. We compared EEG characteristics of patients who developed epilepsy with patients who did not develop epilepsy by the time of their follow-up. Results Eleven children were included in this study. EEG was performed at the median age of 2.1 months (range 1.0–22.1). Six children developed seizures with a time interval between EEG and seizure onset ranging from 2 days to 21 months. EEG background activity was asymmetric in 8 patients, 5 of whom later developed epilepsy. Focal interictal spikes or sharp waves were exclusively recorded in patients who developed later epilepsy (4 out of 6). One of these patients had a supposed false positive EEG as he did not developed epilepsy until 21 months later and one patient had a false negative EEG with seizures occurring 2 days after a normal EEG. Conclusion Spikes on EEG might be a useful marker to identify patients with SWS at risk of developing epilepsy. Their predictive value should be assessed in larger prospective studies.

Recent studies have suggested that the early introduction of a ketogenic diet (KD) could improve seizure control in myoclono-astatic epilepsy (MAE). This multicenter study sought to identify the benefits of KD use on seizure control and epilepsy and on developmental outcomes in children with resistant MAE.Fifty children who were diagnosed with severe MAE in the French network of Reference Centers for Rare Epilepsies and who were treated with KD between 2000 and 2013 were included in this study. The seizure frequency and EEG recordings were assessed two weeks before KD introduction, 2 and 6 months after, and during the last follow-up, which also included an assessment of developmental outcome.Patients had a median follow up of 52 months (range 13-136) and received 4.3 antiepileptic drugs [2-9] before KD introduction. Fifty-four percent (54%) of our patients were seizure-free after 6 months of KD or more, and 86% experienced more than a 70% seizure reduction after 2 months of KD. Forty-four percent (44%) of them had a clear benefit of early KD treatment (after four AEDs failed). Early KD treatment did not result in a greater seizure reduction (p=0.055), but significantly resulted in remission (p0.028). Fifty percent of patients with resistant MAE had normal development outcomes. Earlier KD treatment, after three AEDs failed, was correlated with a better cognitive outcome (p0.01).Early introduction of KD treatment in resistant MAE has a strong, persistent anticonvulsant effect with long-term remission and better cognitive outcomes.

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.

Focal cortical dysplasia (FCD) is the most common cause of intractable focal epilepsy in children, in whom seizures are most commonly pharmacoresistant from onset. This review summarizes the current understandings of the epidemiology, natural history, and the proposed mechanisms of epileptogenisis in FCD. Advances in neuroimaging techniques have enhanced the recognition of this pathology, which can be subtle. Illustrative neurophysiology and imaging examples are provided to help the clinicians identify diagnostic evidence of suspected FCD. Given the refractory course to pharmacologic management, alternative options such as ketogenic diet, resective surgery or neuromodulation can be considered. Recognition of FCD pathology in children with early onset epilepsy should prompt timely evaluations for resective surgery, which may render a significant number of patients seizure-free and improve neurocognitive outcome.

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 Purpose To determine the range of topiramate (TPM) concentrations obtained in children under 4 with the recommended dosage regimen (3–9mg/kg/day) and to compare them to adult target ranges. Methods The population pharmacokinetic model developed for TPM, with/without enzyme inducer antiepileptic drugs (EIAEDs) in children was used to determine dosage regimens providing AUC and trough concentrations ( C trough s) within the adult ranges. Results TPM pharmacokinetics was described by a one-compartment model. EIAEDs increased the apparent clearance (CL/F) and age and body weight increased the apparent distribution volume (Vd/F). Mean population estimates (% CV interindividual variability) were 0.608/1.15L/h (13%) for CL/F without/with EIAEDs, 28.6L (0.2%) for Vd/F and 1.4h −1 (124%) for the absorption rate constant. Mean AUC 0–12h reached with a 2mg/kg/day dosing regimen was within described range. A 6–16mg/kg/day dose depending on age allowed reaching target C trough range with the highest probability. Combined EIAEDs led to a 2- and 3-fold decrease in AUC and C trough , respectively. Conclusion TPM dosage of 2/4mg/kg/day (without/with EIEADs, respectively) provides the AUC reported in adults. In children under 4, alternative dosing regimen should be considered mainly when associated to EIAED to reach C trough comparable to adult values.

Childhood absence epilepsy (CAE) is an idiopathic generalised epilepsy (IGE) characterised by typical absence seizures manifested by transitory loss of awareness with 2.5-4 Hz spike-wave complexes on ictal EEG. A genetic component to the aetiology is wet[ recognised but the mechanism of inheritance and the genes involved are yet to be fully established.A genome wide single nucleotide polymorphism (SNP)-based high density linkage scan was carried out using 41 nuclear pedigrees with at least two affected members. Multipoint parametric and non-parametric linkage analyses were performed using MERLIN 1.1.1 and a susceptibility locus was identified on chromosome 3p23-p14 (Z(mean) = 3.9, p < 0.0001; HLOD = 3.3, alpha = 0.7). The (inked region harbours the functional candidate genes TRAK1 and CACNA2D2. Fine-mapping using a tagSNP approach demonstrated disease association with variants in TRAK1. (C) 2009 Elsevier B.V. All rights reserved.

Summary Background Severe myoclonic epilepsy of infancy (SMEI) or Dravet syndrome (DS) is a distinctive epilepsy syndrome often associated with de novo mutations in the SCN1A gene. However, 25–30% patients with SMEI/DS are negative for SCN1A mutation screening, suggesting that other molecular mechanisms may account for these disorders. Given the overlapping and heterogeneous clinical features of CDKL5 - and ARX -related epilepsies and SMEI/DS, we postulated that CDKL5 mutations in females and ARX mutations gene in males may be associated with early onset seizures forms of SMEI/DS. Methods Twenty-eight patients with early onset SMEI/DS before 6 months negative for SCN1A mutational screening were selected and screened for mutations in the ARX gene in males ( n =14) or the CDKL5 gene in females ( n =14). Results No mutations in either gene were found except one intronic variation of uncertain pathogenicity in the CDKL5 gene. All patients started seizures at mean age of 3.48 months. Thirteen patients had familial history of epilepsy or febrile seizures. Patients evolved toward refractory epilepsy with generalized tonic clonic seizures (18/28) and myoclonia (23/28) and severe neurological impairment with autistic features (13/28), ataxia (14/28) and spasticity (5/28). No patient ever exhibited infantile spasms, dystonia, or Rett-like features. Interpretations Our results illustrate that mutation screening of ARX and CDKL5 is not effective in patients selected on the basis of clinical signs associated to early onset SMEI/DS. In addition, they might reflect that other phenotypic features associated with CDKL5 mutations (Rett-like features, infantile spasm) or ARX mutations (dystonia, spasticity) are more distinctive.

Summary A puzzling EEG pattern combining frontal slow bi–tri spikes followed or not by slow waves when awake and activated by sleep with 5–10 s discharges of 8–9 Hz spikes in a minority of adolescents with Dravet syndrome (DS) was recorded in the context of stable seizure and cognitive status, and unchanged antiepileptic medication. Tonic seizures were frequently reported in patients with this EEG pattern (3/5). This EEG pattern could suggest that of Lennox–Gastaut syndrome (LGS) but it exhibits clear differences and therefore should not be considered as a change into LGS but as a previously overlooked unusual pattern in the adolescent course of DS.

Agyria-pachygyria or lissencephaly type I, a diffuse cortical malformation, provides infantile spasms (IS) which are refractory and persisting after the first decade, an age at which IS have disappeared in the other causes. In order to study the functional postnatal development of the lissencephalic cortex, we measured regional cerebral blood flow (rCBF) using SPECT (Single photon emission computed tomography) and 133Xe in 14 children with lissencephaly, aged from 4 months to 12 years (mean = 40 months) compared to normal children of the same age range and to children with cryptogenic IS aged from 3 months to 3 years (mean = 13 months). rCBF was calculated in frontal (FR) and parieto-temporo-occipital (PTO) cortex as well as the ratio FR/PTO. FR/PTO was higher in lissencephalic patients than in controls (P < 0.001) due to higher FR rCBF (P < 0.001), particularly in patients aged less than 3 years. FR/PTO was also higher in lissencephalic patients than in patients with cryptogenic IS (P < 0.001) also due to higher FR rCBF (P < 0.001). The values of FR/PTO and FR rCBF remained stable during the first years of life and did not exhibit any age- or topography-related changes as they do in controls or in patients with cryptogenic IS. These results suggest that the normal process of postnatal development in the brain is lacking in agyria-pachygyria. That could play a role in determining the persistance of epileptic spasms, the specific seizure type of this malformation.

To investigate the impact of treatment lag in infantile spasms (IS) on treatment response, occurrence of later epilepsy, and long-term cognition and behavior in patients with one single etiological entity, we examined 18 patients with Down syndrome (DS) and earlier IS retrospectively (follow-up period of 32-180 months with a mean of 85.1 months), and determined their history and present condition, in terms of previously mentioned items. There was a statistically significant correlation between treatment lag and lag to cessation of spasms (R=0.55, P=0.02), developmental quotient (DQ) (R=-0.75, P=0.003), and score of autistic features (AF) (R=0.57, P=0.04). Moreover we found that the later the response to treatment of IS, the lower was the DQ (R=-0.86, P=0.001) and the higher was the score of autistic features (R=0.5, P=0.06). A long duration of spasms also determined a low DQ (R=-0.93, P0.0001) and a high score of autistic features (R=0.66, P0.01). All patients with persistent epilepsy (n=5) had had a treatment lag of over 2 months. Conversely, for all children treated within 2 months (n=8) spasms ceased within 3 months of treatment and none of them had later epilepsy. This group of patients with a treatment lag of less than 2 months had earlier treatment response (P=0.002), higher DQ (P=0.004) and lower score of autistic features (P=0.006). The data stress the importance of a short treatment lag in view of mental development and prevention of later epilepsy and autistic features, and raise the question of antiepileptogenic effect in this specific condition.