Optimization of vigabatrin dosage in children with epileptic spasms: A population pharmacokinetic approach.

AIMS: Vigabatrin is an antiepileptic drug used to treat some forms of severe epilepsy in children. The main adverse effect is ocular toxicity, which is related to the cumulative dose. The aim of the study is to identify an acceptable exposure range, both through the development of a population pharmacokinetic model of vigabatrin in children enabling us to calculate patient exposure and through the study of therapeutic response. METHODS: We performed a retrospective study including children with epilepsy followed at Necker-Enfants Malades hospital who had a vigabatrin assay between January 2019 and January 2022. The population pharmacokinetic study was performed on Monolix2021 using a nonlinear mixed-effects modelling approach. Children treated for epileptic spasms were classified into responder and nonresponder groups according to whether the spasms resolved, in order to identify an effective plasma exposure range. RESULTS: We included 79 patients and analysed 159 samples. The median age was 4.2 years (range 0.3-18). A 2-compartment model with allometry and creatinine clearance on clearance best fit our data. Exposure analysis was performed on 61 patients with epileptic spasms. Of the 22 patients who responded (36%), 95% had an AUC0-24 between 264 and 549 mg.h.L-1. CONCLUSIONS: The population pharmacokinetic model allowed us to identify bodyweight and creatinine clearance as the 2 main factors explaining the observed interindividual variability of vigabatrin. An acceptable exposure range was defined in this study. A target concentration intervention approach using this pharmacokinetic model could be used to avoid overexposure in responder patients.

Genotype-phenotype associations in 1018 individuals with SCN1A-related epilepsies.

OBJECTIVE: SCN1A variants are associated with epilepsy syndromes ranging from mild genetic epilepsy with febrile seizures plus (GEFS+) to severe Dravet syndrome (DS). Many variants are de novo, making early phenotype prediction difficult, and genotype-phenotype associations remain poorly understood. METHODS: We assessed data from a retrospective cohort of 1018 individuals with SCN1A-related epilepsies. We explored relationships between variant characteristics (position, in silico prediction scores: Combined Annotation Dependent Depletion (CADD), Rare Exome Variant Ensemble Learner (REVEL), SCN1A genetic score), seizure characteristics, and epilepsy phenotype. RESULTS: DS had earlier seizure onset than other GEFS+ phenotypes (5.3 vs. 12.0 months, p < .001). In silico variant scores were higher in DS versus GEFS+ (p < .001). Patients with missense variants in functionally important regions (conserved N-terminus, S4-S6) exhibited earlier seizure onset (6.0 vs. 7.0 months, p = .003) and were more likely to have DS (280/340); those with missense variants in nonconserved regions had later onset (10.0 vs. 7.0 months, p = .036) and were more likely to have GEFS+ (15/29, χ2 = 19.16, p < .001). A minority of protein-truncating variants were associated with GEFS+ (10/393) and more likely to be located in the proximal first and last exon coding regions than elsewhere in the gene (9.7% vs. 1.0%, p < .001). Carriers of the same missense variant exhibited less variability in age at seizure onset compared with carriers of different missense variants for both DS (1.9 vs. 2.9 months, p = .001) and GEFS+ (8.0 vs. 11.0 months, p = .043). Status epilepticus as presenting seizure type is a highly specific (95.2%) but nonsensitive (32.7%) feature of DS. SIGNIFICANCE: Understanding genotype-phenotype associations in SCN1A-related epilepsies is critical for early diagnosis and management. We demonstrate an earlier disease onset in patients with missense variants in important functional regions, the occurrence of GEFS+ truncating variants, and the value of in silico prediction scores. Status epilepticus as initial seizure type is a highly specific, but not sensitive, early feature of DS.

Interhemispheric Vertical Hemispherotomy: Technique, Outcome, and Pitfalls-A Bicentric Retrospective Case Series of 39 Cases.

BACKGROUND AND OBJECTIVES: When seizure onset affects a whole hemisphere, hemispheric disconnections are efficient and safe procedures. However, both lateral peri-insular hemispherotomy and vertical paramedian hemispherotomy approaches report a failure rate around 20%, which can be explained by residual connections giving rise to persistent seizures. In this study, we present the interhemispheric vertical hemispherotomy (IVH), a technical variation of the vertical paramedian hemispherotomy approach, that aims to increase seizure control avoiding residual connections while exposing the corpus callosum. METHODS: This is a retrospective study of IVH in two centers, with analysis of clinical and MRI data and outcomes. A detailed description of the technique is provided with a video. RESULTS: IVH was performed in 39 children. The mean age at surgery was 7.2 years, and etiologies were as follows: malformations of cortical development (n = 14), Rasmussen's encephalitis (n = 10), stroke (n = 10), post-traumatic (3), and Sturge-Weber Syndrome (2). Hemispheric disconnection was complete on postoperative MRI in 34 cases. There was no mortality, hydrocephalus occurred in one case, and subdural collection occurred in four cases. A second surgery was performed in four cases because of seizure relapse (n = 3) and/or incomplete disconnection on MRI (n = 4). With a mean follow-up of 3.2 years, International League Against Epilepsy class I epilepsy outcome was obtained for 37/39 patients. CONCLUSION: IVH is a safe and effective variation of the vertical approaches for hemispheric disconnection. It allows a good exposure and anatomic control of the corpus callosum, which is a frequent site of incomplete disconnection. IVH may be limited by the thalamic volume and the ventricular size, notably in hemimegalencephaly cases.

Fifteen years of real-world data on the use of vigabatrin in individuals with infantile epileptic spasms syndrome.

OBJECTIVE: This study was undertaken to evaluate our treatment algorithm for infantile epileptic spasms syndrome (IESS) used between 2000 and 2018. We initiated vigabatrin (VGB), and steroids were added if the electroclinical response (spasms and electroencephalogram [EEG]) to VGB was not obtained or incomplete. METHODS: Individuals with IESS treated with VGB were recruited from our hospital clinical data warehouse based on electronic health records (EHRs) generated since 2009 and containing relevant keywords. We confirmed the diagnosis of IESS. Clinical, EEG, imaging, and biological data were extracted from the EHRs. We analyzed factors associated with short-term response, time to response, relapse, time to relapse of spasms, and the presence of spasms at last follow-up. RESULTS: We collected data from 198 individuals (female: 46.5%, IESS onset: 6 [4.5-10.3] months, follow-up: 4.6 [2.5-7.6] years, median [Q1-Q3]) including 129 (65.2%) with identifiable etiology. VGB was started 17 (5-57.5) days after IESS diagnosis. A total of 113 individuals were responders (57.1% of the cohort), 64 with VGB alone and 38 with VGB further combined with steroids (56.6% and 33.6% of responders, respectively). Among responders, 33 (29%) experienced relapses of spasms, mostly those with later onset of spasms (p = .002) and those who received VGB for <24 months after spasms cessation compared to a longer duration on VGB (45% vs. 12.8%, p = .003). At follow-up, 92 individuals were seizure-free (46.5% of the whole cohort), including 26 free of therapy (13.1%). One hundred twelve individuals (56.6%) were still receiving VGB, with a duration of 3.2 (1.75-5.7) years. SIGNIFICANCE: Our sequential protocol introducing VGB then adding steroids is an effective alternative to a combined VGB-steroids approach in IESS. It avoids steroid-related adverse events, as well as those from VGB-steroid combination. According to our data, a period of 7 days seems sufficient to assess VGB response and enables the addition of steroids rapidly if needed. Continuing VGB for 2 years may balance the risk of relapse and treatment-induced adverse events.

Association between acute complications in PMM2-CDG patients and haemostasis anomalies: Data from a multicentric study and suggestions for acute management.

OBJECTIVES: Patients with PMM2-CDG develop acute events (stroke-like episodes (SLEs), thromboses, haemorrhages, seizures, migraines) associated with both clotting factors (factor XI) and coagulation inhibitors (antithrombin, protein C and protein S) deficiencies. The aim of the study was to correlate acute events to haemostasis and propose practical guidelines. METHODS: In this multicentric retrospective study, we evaluated clinical, radiological, haemostasis and electroencephalography data for PMM2-CDG patients hospitalized for acute events. Cerebral events were classified as thrombosis, haemorrhage, SLE, or "stroke mimic" (SM: normal brain imaging or evoking a migraine). RESULTS: Thirteen patients had a total of 31 acute episodes: 27 cerebral events with 7 SLEs, 4 venous thromboses, 4 haemorrhages (3 associated with thrombosis), 15 SMs at a mean age of 7.7 years; 4 non-cerebral thromboses, one of which included bleeding. A trigger was frequently involved (infection, head trauma). Although sometimes normal at baseline state, factor XI, antithrombin and protein C levels decreased during these episodes. No correlation between haemostasis anomalies and type of acute event was found. DISCUSSION: Acute events in PMM2-CDG are not negligible and are associated with haemostasis anomalies. An emergency protocol is proposed for their prevention and treatment (https://www.filiere-g2m.fr/urgences). For cerebral events, brain Magnetic Resonance Imaging with perfusion weight imaging and diffusion sequences, electroencephalogram and haemostasis protein levels guide the treatment: anticoagulation, antithrombin or fresh frozen plasma supplementation, antiepileptic therapy. Preventing bleeding and thrombosis is required in cases of surgery, prolonged immobilization, hormone replacement therapy. CONCLUSION: Acute events in PMM2-CDG are associated with abnormal haemostasis, requiring practical guidance.

Initiating stiripentol before 2 years of age in patients with Dravet syndrome is safe and beneficial against status epilepticus.

AIM: To evaluate the safety and efficacy of stiripentol initiated before 2 years of age in patients with Dravet syndrome. METHOD: This was a 30-year, real-world retrospective study. We extracted the data of the 131 patients (59 females, 72 males) who initiated stiripentol before 2 years of age between 1991 and 2021 from the four longitudinal databases of Dravet syndrome available in France. RESULTS: Stiripentol was added to valproate and clobazam (93%) at 13 months and a median dose of 50 mg/kg/day. With short-term therapy (<6 months on stiripentol, median 4 months, median age 16 months), the frequency of tonic-clonic seizures (TCS) lasting longer than 5 minutes decreased (p < 0.01) and status epilepticus (>30 minutes) disappeared in 55% of patients. With long-term therapy (last visit on stiripentol <7 years of age, median stiripentol 28 months, median age 41 months), the frequency of long-lasting TCS continued to decline (p = 0.03). Emergency hospitalizations dropped from 91% to 43% and 12% with short- and long-term therapies respectively (p < 0.001). Three patients died, all from sudden unexpected death in epilepsy. Three patients discontinued stiripentol for adverse events; 55% reported at least one adverse event, mostly loss of appetite/weight (21%) and somnolence (11%). Stiripentol was used earlier, at lower doses, and was better tolerated by patients in the newest database than in the oldest (p < 0.01). INTERPRETATION: Initiating stiripentol in infants with Dravet syndrome is safe and beneficial, significantly reducing long-lasting seizures including status epilepticus, hospitalizations, and mortality in the critical first years of life.

The longitudinal evolution of cerebral blood flow in children with tuberous sclerosis assessed by arterial spin labeling magnetic resonance imaging may be related to cognitive performance.

OBJECTIVE: To study longitudinal changes in tuber and whole-brain perfusion in children with tuberous sclerosis complex (TSC) using arterial spin labeling (ASL) perfusion MRI and correlate them with pathological EEG slow wave activity and neurodevelopmental outcomes. METHODS: Retrospective longitudinal cohort study of 13 children with TSC, 3 to 6 serial ASL-MRI scans between 2 months and 7 years of age (53 scans in total), and an EEG examination performed within 2 months of the last MRI. Tuber cerebral blood flow (CBF) values were calculated in tuber segmentation masks, and tuber:cortical CBF ratios were used to study tuber perfusion. Logistic regression analysis was performed to identify which initial tuber characteristics (CBF value, volume, location) in the first MRI predicted tubers subsequently associated with EEG slow waves. Whole-brain and lobar CBF values were extracted for all patient scans and age-matched controls. CBF ratios were compared in patients and controls to study longitudinal changes in whole-brain CBF. RESULTS: Perfusion was reduced in tubers associated with EEG slow waves compared with other tubers. Low tuber CBF values around 6 months of age and large tuber volumes were predictive of tubers subsequently associated with EEG slow waves. Patients with severe developmental delay had more severe whole-brain hypoperfusion than those with no/mild delay, which became apparent after 2 years of age and were not associated with a higher tuber load. CONCLUSIONS: Dynamic changes in tuber and brain perfusion occur over time. Perfusion is significantly reduced in tubers associated with EEG slow waves. Whole-brain perfusion is significantly reduced in patients with severe delay. KEY POINTS: • Tubers associated with EEG slow wave activity were significantly more hypoperfused than other tubers, especially after 1 year of age. • Larger and more hypoperfused tubers at 6 months of age were more likely to subsequently be associated with pathological EEG slow wave activity. • Patients with severe developmental delay had more extensive and severe global hypoperfusion than those without developmental delay.

Periodic electroencephalographic discharges and epileptic spasms involve cortico-striatal-thalamic loops on Arterial Spin Labeling Magnetic Resonance Imaging.

Periodic discharges are a rare peculiar electroencephalogram pattern, occasionally associated with motor or other clinical manifestations, usually observed in critically ill patients. Their underlying pathophysiology remains poorly understood. Epileptic spasms in clusters and periodic discharges with motor manifestations share similar electroencephalogram pattern and some aetiologies of unfavourable prognosis such as subacute sclerosing panencephalitis or herpes encephalitis. Arterial spin labelling magnetic resonance imaging identifies localizing ictal and inter-ictal changes in neurovascular coupling, therefore assumed able to reveal concerned cerebral structures. Here, we retrospectively analysed ictal and inter-ictal arterial spin labelling magnetic resonance imaging in patients aged 6 months to 15 years (median 3 years 4 months) with periodic discharges including epileptic spasms, and compared these findings with those of patients with drug-resistant focal epilepsy who never presented periodic discharges nor epileptic spasms as well as to those of age-matched healthy controls. Ictal electroencephalogram was recorded either simultaneously with arterial spin labelling magnetic resonance imaging or during the close time lapse of patients' periodic discharges, whereas inter-ictal examinations were performed during the patients' active epilepsy but without seizures during the arterial spin labelling magnetic resonance imaging. Ictal arterial spin labelling magnetic resonance imaging was acquired in five patients with periodic discharges [subacute sclerosing panencephalitis (1), stroke-like events (3), West syndrome with cortical malformation (1), two of them also had inter-ictal arterial spin labelling magnetic resonance imaging]. Inter-ictal group included patients with drug-resistant epileptic spasms of various aetiologies (14) and structural drug-resistant focal epilepsy (8). Cortex, striatum and thalamus were segmented and divided in six functional subregions: prefrontal, motor (rostral, caudal), parietal, occipital and temporal. Rest cerebral blood flow values, absolute and relative to whole brain, were compared with those of age-matched controls for each subregion. Main findings were diffuse striatal as well as cortical motor cerebral blood flow increase during ictal examinations in generalized periodic discharges with motor manifestations (subacute sclerosing panencephalitis) and focal cerebral blood flow increase in corresponding cortical-striatal-thalamic subdivisions in lateralized periodic discharges with or without motor manifestations (stroke-like events and asymmetrical epileptic spasms) with straight topographical correlation with the electroencephalogram focus. For inter-ictal examinations, patients with epileptic spasms disclosed cerebral blood flow changes in corresponding cortical-striatal-thalamic subdivisions (absolute-cerebral blood flow decrease and relative-cerebral blood flow increase), more frequently when compared with the group of drug-resistant focal epilepsies, and not related to Vigabatrin treatment. Our results suggest that corresponding cortical-striatal-thalamic circuits are involved in periodic discharges with and without motor manifestations, including epileptic spasms, opening new insights in their pathophysiology and new therapeutical perspectives. Based on these findings, we propose a model for the generation of periodic discharges and of epileptic spasms combining existing pathophysiological models of cortical-striatal-thalamic network dynamics.

Development and Validation of a Prediction Model for Early Diagnosis of SCN1A-Related Epilepsies.

BACKGROUND AND OBJECTIVES: Pathogenic variants in the neuronal sodium channel α1 subunit gene (SCN1A) are the most frequent monogenic cause of epilepsy. Phenotypes comprise a wide clinical spectrum, including severe childhood epilepsy; Dravet syndrome, characterized by drug-resistant seizures, intellectual disability, and high mortality; and the milder genetic epilepsy with febrile seizures plus (GEFS+), characterized by normal cognition. Early recognition of a child's risk for developing Dravet syndrome vs GEFS+ is key for implementing disease-modifying therapies when available before cognitive impairment emerges. Our objective was to develop and validate a prediction model using clinical and genetic biomarkers for early diagnosis of SCN1A-related epilepsies. METHODS: We performed a retrospective multicenter cohort study comprising data from patients with SCN1A-positive Dravet syndrome and patients with GEFS+ consecutively referred for genetic testing (March 2001-June 2020) including age at seizure onset and a newly developed SCN1A genetic score. A training cohort was used to develop multiple prediction models that were validated using 2 independent blinded cohorts. Primary outcome was the discriminative accuracy of the model predicting Dravet syndrome vs other GEFS+ phenotypes. RESULTS: A total of 1,018 participants were included. The frequency of Dravet syndrome was 616/743 (83%) in the training cohort, 147/203 (72%) in validation cohort 1, and 60/72 (83%) in validation cohort 2. A high SCN1A genetic score (133.4 [SD 78.5] vs 52.0 [SD 57.5]; p < 0.001) and young age at onset (6.0 [SD 3.0] vs 14.8 [SD 11.8] months; p < 0.001) were each associated with Dravet syndrome vs GEFS+. A combined SCN1A genetic score and seizure onset model separated Dravet syndrome from GEFS+ more effectively (area under the curve [AUC] 0.89 [95% CI 0.86-0.92]) and outperformed all other models (AUC 0.79-0.85; p < 0.001). Model performance was replicated in both validation cohorts 1 (AUC 0.94 [95% CI 0.91-0.97]) and 2 (AUC 0.92 [95% CI 0.82-1.00]). DISCUSSION: The prediction model allows objective estimation at disease onset whether a child will develop Dravet syndrome vs GEFS+, assisting clinicians with prognostic counseling and decisions on early institution of precision therapies (http://scn1a-prediction-model.broadinstitute.org/). CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that a combined SCN1A genetic score and seizure onset model distinguishes Dravet syndrome from other GEFS+ phenotypes.

A European pilot study in Dravet Syndrome to delineate what really matters for the patients and families.

We aimed to identify caregivers' opinions on the outcome measures that matter in clinical trials in individuals with Dravet syndrome (DS). We conducted a prospective European multicenter study based on an 11 closed questions survey developed by the French reference center for rare epilepsies and DS patients' advocacy groups. Items included questions on seizures and daily life outcomes that a clinical trial on a therapy for individuals with DS should target. Statistical analyses were performed to evaluate the impact of the country of residence and of the patients' age. The survey was answered by 153 caregivers (68%: France, 28%: Germany, and 24%: Italy) off individuals with DS. Individuals with DS included 86 males (mean age of 11.4 [interquartile: 7-20.4] years). Families ranked as important almost all the items proposed. However, items related to daily life had the highest rank in all three countries compared to items about seizures (P = 0.02). Increase in individuals' age was associated with a higher age at diagnosis (ρ = 0.26, P = 0.02), and a lower impact of seizure duration (ρ = -0.25, P = 0.005) and on the need of hospital referral (ρ = -0.26, P = 0.005). These data can help tailor patient-centered outcome measures in future clinical and real-life trials for DS.

Predictive Performance of Population Pharmacokinetic Models of Levetiracetam in Children and Evaluation of Dosing Regimen.

Levetiracetam is a broad-spectrum antiepileptic drug that exhibits high interindividual variability in serum concentrations in children. A population pharmacokinetic approach can be used to explain this variability and optimize dosing schemes. The objectives are to identify the best predictive population pharmacokinetic model for children and to evaluate recommended doses using simulations and Bayesian forecasting. A validation cohort included children treated with levetiracetam who had a serum drug concentration assayed during therapeutic drug monitoring. We assessed the predictive performance of all the population pharmacokinetic models published in the literature using mean prediction errors, root mean squared errors, and visual predictive checks. A population model was finally constructed on the data, and dose simulations were performed to evaluate doses. We included 267 levetiracetam concentrations ranging from 2 to 69 mg/L from 194 children in the validation cohort. Six published models were externally evaluated. Most of the models underestimated the variability of our population. A 1-compartment model with first-order absorption and elimination with allometric scaling was finally fitted on our data. In our cohort, 57% of patients had a trough concentration <12 mg/L and 12% <5 mg/L. To reach a trough concentration >5 mg/L, doses ≥30 mg/kg/d for patients ≤50 kg and ≥2000 mg/d for patients >50 kg are required. In our population, a high percentage of children had low trough concentrations. Our population pharmacokinetic model could be used for therapeutic drug monitoring of levetiracetam in children.

Jerking during absences: video-EEG and polygraphy of epileptic myoclonus associated with two paediatric epilepsy syndromes.

Epileptic myoclonus (EM) is reported in many paediatric epilepsies from neonatal period to adolescence. Myoclonus can be the only seizure type or may occur among others, independently or in combination as a single ictal event. We report two children presenting with absences associated with myoclonus, predominating on one side, in a setting of two different types of absence seizures and two different electro-clinical syndromes. Patients were explored with long-duration video-EEG coupled to surface EMG polygraphy. EEG was visually analysed and complemented by jerk-locked back-averaging. Two types of seizure, encompassing myoclonus and absence, were identified: myoclonic absences in the context of epilepsy with myoclonic absences and atypical absences with atonic component (negative myoclonus) in the context of encephalopathy related to status epilepticus during slow sleep (ESES). In the latter case, rhythmic upper limb jerking, mimicking positive myoclonus, corresponded to recovery of muscular tone after each negative myoclonus. Due to the rhythmic recovery of muscle tone, subsequent rhythmic negative myoclonus may exhibit a similar clinical picture to that of rhythmic positive myoclonus. Video-EEG recording coupled to EMG polygraphy is essential in order to precisely characterize motor manifestations during seizures with myoclonus [Published with video sequences].

SYNGAP1-DEE: A visual sensitive epilepsy.

OBJECTIVE: To further delineate the electroclinical features of individuals with SYNGAP1 pathogenic variants. METHODS: Participants with pathogenic SYNGAP1 variants and available video-electroencephalogram (EEG) recordings were recruited within five European epilepsy reference centers. We obtained molecular and clinical data, analyzed EEG recordings and archived video-EEGs of seizures and detailed characteristics of interictal and ictal EEG patterns for every patient. RESULTS: We recruited 15 previously unreported patients and analyzed 72 EEGs. Two distinct EEG patterns emerged, both triggered by eye closure. Pattern 1 (14/15 individuals) consisted of rhythmic posterior/diffuse delta waves appearing with eye-closure and persisting until eye opening (strongly suggestive of fixation-off sensitivity). Pattern 2 (9/15 individuals) consisted of diffuse polyspike-and-wave discharges triggered by eye closure (eye-closure sensitivity). Both patterns presented in 8/15. Including archived video-EEG clips of seizures from 9/15 patients, we analyzed 254 seizures. Of 224 seizures experienced while awake, 161 (72%) occurred at or following eye closure. In 119/161, pattern 1 preceded an atypical absence, myoclonic seizure or myoclonic absence; in 42/161, pattern 2 was associated with eyelid myoclonia, absences and myoclonic or atonic seizures. CONCLUSIONS: Fixation-off and eye closure were the main triggers for seizures in this SYNGAP1 cohort. SIGNIFICANCE: Combining these clinical and electroencephalographic features could help guide genetic diagnosis.

Real-life use of videos in pediatric epilepsy consultations.

Paroxysmal events are usually not directly observed by physicians. The diagnosis remains challenging and relies mostly on the description of witnesses. The effectiveness of videos for seizure diagnosis has been validated by several studies, but their place in clinical practice is not yet clear. The aim of our study was to evaluate the real-life use of videos by child neurologists. We conducted a three-month prospective study in which child neurologists were asked to use a short questionnaire to evaluate all videos that were watched in their clinical practice for an initial diagnosis or during follow-up. A click-off meeting during the French pediatric neurology meeting allowed to recruit participants. A total of 165 questionnaires were completed by 15 physicians over the study period. The physicians were child neurologists working in secondary and tertiary/university hospitals, consulting children with epilepsy. Based on the evaluation of child neurologists, 51% of the videos consisted of epileptic seizures; 40%, nonepileptic paroxysmal events; and 9%, psychogenic nonepileptic seizures. Most of the videos were made on parental initiative. The use of video has modified the first diagnosis hypothesis in 35% of cases. The physicians' feelings regarding the interest of the video used during the diagnostic phase were similar to those of the video used during follow-up. It appears that videos have become a part of the epilepsy clinic and are helpful for diagnosis as well as during follow-up. Unfortunately, one of the limitations of this study is the absence of private practitioner.

Slow Titration of Cannabidiol Add-On in Drug-Resistant Epilepsies Can Improve Safety With Maintained Efficacy in an Open-Label Study.

Objective: To assess adverse events (AEs) and efficacy of add-on cannabidiol (CBD) with a slower titration protocol in pediatric clinical practice. Methods: We conducted a prospective, open-label, multicenter study in seven French reference centers for rare epilepsies. Patients had slow titration to reach a target dose of 10 mg/kg/day within at least 1 month and then gradually increased to a maximum dose of 20 mg/kg/day. We analyzed AEs and efficacy at M1 (month 1), M2, and M6, comparing two sets of subgroups: Dravet syndrome (DS) vs. Lennox-Gastaut (LGS) and patients with clobazam (CLB+) vs. patients without (CLB-). Results: One hundred and twenty-five patients were enrolled (62 LGS, 48 DS, 5 Tuberous sclerosis, and 10 other etiologies). Median concomitant antiepileptic drugs (AEDs) was three (25th percentile: 3, 75th percentile: 4). Patients received a dose of 10 (10-12), 14 (10-20), and 15.5 mg/kg/day (10-20) at M1, M2, and M6, respectively. Twenty-six patients discontinued CBD, 19 due to lack of efficacy, 2 due to AEs, 4 for both, and 1 had a sudden unexpected death in epilepsy. AEs were reported in 61 patients (48.8%), mainly somnolence (n = 26), asthenia (n = 20), and behavior disorders (n = 16). Abnormal transaminases (≥3 times) were reported in 11 patients receiving both valproate and clobazam. AEs were significantly higher at M2 (p = 0.03) and increased with the number of AEDs (p = 0.03). At M6, total seizure frequency change from baseline was -41% ± 37.5% (mean ± standard deviation), and 28 patients (37.8%) had a reduction ≥50%. AE and efficacy did not differ between DS vs. LGS and CLB+ vs. CLB- patients. Significance: A slower titration of CBD dose delivered better tolerance with comparable efficacy to previous trials. Concomitant CLB did not increase efficacy rates but in a few cases increased AEs. This slow titration scheme should help guide clinicians prescribing CBD and allow patients to benefit from its potential efficacy.

Add-on cannabidiol significantly decreases seizures in 3 patients with SYNGAP1 developmental and epileptic encephalopathy.

Mutations in SYNGAP1 are associated with developmental delay, epilepsy, and autism spectrum disorder (ASD). Epilepsy is often drug-resistant in this syndrome with frequent drop attacks. In a prospective study of add-on cannabidiol (CBD), we identified three patients with SYNGAP1 mutations: two boys and one girl. Seizure onset was at 3.5, 8, and 18 months (M), respectively, with numerous atypical absences per day associated with eyelid myoclonia (2/3 patients), upper limb myoclonic jerks (2/3 patients), and drop attacks (all patients). Seizures were resistant to at least 5 antiepileptic drugs (AEDs). After CBD introduction, two patients were responders since M2 and achieve a seizure reduction of 90% and 80%, respectively, at M9 with disappearance of drop attacks. EEGs showed an improvement regarding background activity and interictal anomalies. The last patient showed a late response at M7 of treatment with an 80% decrease in seizure frequency. Caregiver in all three evaluated as much improved the status of their children. Treatment was well-tolerated in all, and no major adverse events (AEs) were reported. CBD showed efficacy in patients with drug-resistant epilepsy due to SYNGAP1 mutations. Other patients with rare genetic developmental and epileptic encephalopathies with drug-resistant epilepsies might benefit from CBD.

Head circumferences of patients with Dravet syndrome show growth slowdown.

The measurement of head circumference (HC) represents a useful and reliable tool to monitor brain growth. Many genetic conditions are associated with an abnormal pattern of head growth, but no specific pattern has been described in Dravet Syndrome (DS). To investigate the head growth trajectories in a pediatric population with DS, a retrospective analysis of medical records of patients with DS was performed in 2 epilepsy centers. Quantitative data were compared with z-score growth curve of standard population, and an independent samples t-test was performed using 6-month ranges. A total of 137 subjects aged less than 18 years were included, with a total of 529 HC values and a mean of 3.9 measures per patient. From birth until 24 months of life, HC values were almost equally distributed around the mean trajectory of the reference population from each side of the curve. This trend line deflects from the mean curve after 24 months showing a head growth slowdown reaching a statistical significance (p < .05) from 48 months for males and 60 for females. Future prospective studies are needed to assess factors that can impact head growth and explore possible phenotype-genotype correlation with HC.

Impact of childhood Dravet syndrome on care givers of patients with DS, a major impact on mothers.

BACKGROUND: The aim of this study was to understand the impact of Dravet syndrome (DS) on patients with Dravet syndrome and their families, with a focus on the social and economic impact on both mothers and fathers. METHODS: A French language on-line survey was distributed (October 2014-January 2015) for completion by caregivers of patients aged <18 years with DS. The survey was hosted on the French Dravet Syndrome Alliance website, and the survey link was provided to patients and caregivers during clinics at the Necker Hospital (Paris, France). RESULTS: Survey responses were available for 91 patients (median age 7.6 years; 81.6% SCN1A mutation positive). Total seizure frequency was >2 per week for 16.1% of patients, 1-8 per month for 55.2% and < 1 per month for 28.7%; tonic-clonic and myoclonic were the most frequent seizure types. Patients showed various degrees of intellectual disability and DS had a high impact on concentration and school learning in 70.1% and 80.5%. In addition, patients showed appetite disorders in 73.6%, sleep disorders in 72.4% and behavior disorders in 62.1%. Most parents were married (80.5%) with higher rates than the French general population (53.5%). Educational achievement and socio-professional categories for the parents were higher than observed in the French general population, while monthly net income was similar. Preparation of medication was generally done by the mother and father (46.0% of patients) or the mother only (37.9%). Most caregivers reported very low or no difficulty with treatment preparation and low or no risk of error. Parents typically spent <30 min per day on treatment preparation and administration and around 4 h per week for attending therapy appointments. Although most patients and parents were perceived to have good general health, mothers had a worse perception of their own general health than fathers. Compared with fathers, mothers reported a greater impact of caring for a child with DS on their social life, relationships with family and friends, time and energy, and professional life. CONCLUSION: Families caring for a child with DS experience considerable social and economic impact, with an apparent greater burden of care on the mother than the father.

Transition of patients with childhood onset epilepsy: Perspectives from pediatric and adult neurologists.

Transition from pediatric to adult care systems is a major challenge in the management of adolescents with epilepsy. The comparison of pediatric and adult physicians' points of view on this issue is scarcely described. The aim of this study was to understand pediatric and adult neurologists' experience and opinions on transition in epilepsy in France. We investigate the age at which they usually transfer patients, their opinion on the factors that positively or negatively impact transition, on the help provided during this transition period, and their propositions to improve this process. We prepared a targeted questionnaire with two versions, one adapted for neurologists and the other for child neurologists. The questionnaires were diffused through the Reference Centre for Rare Epilepsies, the French Chapter of the League Against Epilepsy, the French Association for Office-based Neurologists, and the French Pediatric Neurology Society. A total of sixty-eight physicians involved mostly in epilepsy care answered this questionnaire: 39 child neurologists and 29 neurologists. Questionnaires were filled at 96.8%. Twenty-six child neurologists followed patients aged over 18 years (70%), and 18 neurologists followed patients under the age of 12 years (66.6%). Cognitive impairment in childhood led significantly to a later transfer to adult care. The major factors believed to delay the transfer were attachment between child neurologists and families as reported in 96.3% by neurologists and in 81.1% by child neurologists, p = 0.07 and lack of adaptation of adult neurology facilities to adolescents especially with intellectual disability (59.3% neurologists, 75.7% child neurologists, p = 0.16). Factors that helped a transfer around 18-19 years were mainly pharmacoresistant epilepsy (71% for neurologists vs. 19% for child neurologists, p < 105) and pregnancy (72% for child neurologists versus 50% for neurologists, p = 0.08). Factors that negatively impacted transition were the lack of information about daily life in adulthood (driving license, contraception, sexuality, carrier guidance, etc.), the weak transition preparation in pediatric system, the lack of knowledge of pediatric epilepsy syndromes, and the lack of global support for patients with intellectual disability and multidisciplinary care needs in adult system. Both groups proposed joint clinics (>65% of providers) and development of care networks between pediatric and adult care for patients with epilepsy (>55%) to improve transition as well as introducing courses on transition. Few physicians were aware of transition and transfer recommendations. Although child and adult neurologists still have some preconceived beliefs, they were able to identify the strengths and weaknesses of both care systems paving the way for proposals to improve transition and transfer of patients with epilepsy from pediatric to adult care.

Epilepsy with migrating focal seizures: KCNT1 mutation hotspots and phenotype variability.

OBJECTIVE: To report new sporadic cases and 1 family with epilepsy of infancy with migrating focal seizures (EIMFSs) due to KCNT1 gain-of-function and to assess therapies' efficacy including quinidine. METHODS: We reviewed the clinical, EEG, and molecular data of 17 new patients with EIMFS and KCNT1 mutations, in collaboration with the network of the French reference center for rare epilepsies. RESULTS: The mean seizure onset age was 1 month (range: 1 hour to 4 months), and all children had focal motor seizures with autonomic signs and migrating ictal pattern on EEG. Three children also had infantile spasms and hypsarrhythmia. The identified KCNT1 variants clustered as "hot spots" on the C-terminal domain, and all mutations occurred de novo except the p.R398Q mutation inherited from the father with nocturnal frontal lobe epilepsy, present in 2 paternal uncles, one being asymptomatic and the other with single tonic-clonic seizure. In 1 patient with EIMFS, we identified the p.R1106Q mutation associated with Brugada syndrome and saw no abnormality in cardiac rhythm. Quinidine was well tolerated when administered to 2 and 4-year-old patients but did not reduce seizure frequency. CONCLUSIONS: The majority of the KCNT1 mutations appear to cluster in hot spots essential for the channel activity. A same mutation can be linked to a spectrum of conditions ranging from EMFSI to asymptomatic carrier, even in the same family. None of the antiepileptic therapies displayed clinical efficacy, including quinidine in 2 patients.