Severe Childhood-onset Epilepsy Research Articles

A quantitative cross-sectional study of the burden of caring for patients with Lennox-Gastaut syndrome, Dravet syndrome, and tuberous sclerosis complex-associated epilepsy in Japan

IntroductionLennox-Gastaut syndrome (LGS), Dravet syndrome (DS), and tuberous sclerosis complex (TSC)-associated epilepsy are rare conditions associated with severe childhood-onset epilepsy. Caregivers play a critical role in the patients’ care and may experience significant psychosocial and socioeconomic burden. This cross-sectional study determined the burden of caring for patients with these rare epilepsy conditions in Japan. MethodsA quantitative online survey was used to assess patients’ and caregivers’ characteristics and the caregivers’ emotional state, among others. Several validated questionnaires were used: the Hospital Anxiety and Depression Scale (HADS; 0–21 score) assessed the caregivers’ emotional wellbeing, the Pediatric Quality of Life Inventory Family Impact Module (PedsQL FIM; 0–100 score) assessed the health-related quality of life (HRQoL) of the caregivers and their families, and the Work Productivity and Activity Impairment General Health (WPAI:GH; 0–100 % score) questionnaire assessed work productivity. ResultsA total of 36 caregivers responded (median [interquartile range (IQR)] age 43.5 [39.5, 48.3] years; 33/36 [92 %] female; 13/36 [36 %] working part-time and 13/36 [36 %] not working). Participants cared for 7/36 (19 %), 19/36 (53 %), and 10/36 (28 %) patients with LGS, DS, and TSC, respectively (median [IQR] age, 11.0 [6.8, 16.3] years; age at first seizure, 0 [0, 0] years). Patients received a median (IQR) of 4 (3, 5) treatment drug types. Patients experienced median (IQR) 3.0 (0, 21.0) epileptic seizures in the previous week; 28/36 (78 %) had severe intellectual disabilities, and 34/36 (94 %) had developmental delays. Caregivers reported stress (17/36 [47 %]), sleep problems (13/36 [36 %]), and anxiety (12/36 [33 %]). They spent a median (IQR) of 50.0 (17.5, 70.0) hours caregiving in the previous week, with 3.0 (1.0, 11.0) hours of seizure-specific care. Caregivers reported that their lives would be easier with a median (IQR) of 1.5 (0, 5.0) hours fewer per week caring for patients during/following seizures. Median HADS scores were 9.5 (‘suspected anxiety diagnosis’) and 7.5 (‘no depression’) for caregivers, and PedsQL FIM Total median score was 60.1, indicating HRQoL impairment for the caregiver and their family. WPAI:GH scores for paid workers indicated important work impairment. Higher caregiving hours (≥ 21 h vs. < 21 h in the previous week) resulted in higher caregiver burden as indicated by the HADS Total score (p = 0.0062) and PedsQL FIM Total score (p = 0.0007). ConclusionsCaregivers of patients with LGS, DS, or TSC in Japan experience a significant time burden, reduced HRQoL, and high level of work/activity impairment. Caregivers provide round-the-clock care to patients and rely on family and specialized caring services to help manage the increased caregiving time, which tends to be associated with greater emotional burden and HRQoL impact.

Lennox–Gastaut Syndrome: Challenges in Diagnosis – Interviews with Two Key Opinion Leaders

Lennox–Gastaut syndrome (LGS) is a severe childhood-onset epilepsy syndrome that can be challenging to identify due to its heterogeneous and evolving presentation. During interviews conducted by EMJ in July and August 2023, Karen Keough, a child neurologist specialising in paediatric refractory epilepsy at Texas A&amp;M University School of Medicine, Round Rock, USA, and Rhys Thomas, an adult neurologist specialising in epilepsy (leading on learning disability and genetic testing) at the Royal Victoria Infirmary, Newcastle, UK, and Newcastle University, UK, gave their informed opinions on the challenges of diagnosing LGS. The experts spoke about the characteristic features of LGS, and how its gradual evolution from childhood onset can impede diagnosis. In particular, the issues around diagnosing LGS in adulthood, after considerable disease evolution and against a background of uncertain/incomplete medical history, were discussed. The experts also considered the 2022 International League Against Epilepsy (ILAE) position paper for the definition of epilepsy syndromes in childhood, and its potential impact for directing the diagnosis of LGS. Keough and Thomas concluded by describing how raised awareness, vigilance, and support in diagnosis could help to optimise treatment and readjust the goals for the management of adults and children with LGS.

Functional Investigation of a Neuronal Microcircuit in the CA1 Area of the Hippocampus Reveals Synaptic Dysfunction in Dravet Syndrome Mice.

Dravet syndrome is severe childhood-onset epilepsy, caused by loss of function mutations in the SCN1A gene, encoding for the voltage-gated sodium channel NaV1.1. The leading hypothesis is that Dravet is caused by selective reduction in the excitability of inhibitory neurons, due to hampered activity of NaV1.1 channels in these cells. However, these initial neuronal changes can lead to further network alterations. Here, focusing on the CA1 microcircuit in hippocampal brain slices of Dravet syndrome (DS, Scn1aA1783V/WT) and wild-type (WT) mice, we examined the functional response to the application of Hm1a, a specific NaV1.1 activator, in CA1 stratum-oriens (SO) interneurons and CA1 pyramidal excitatory neurons. DS SO interneurons demonstrated reduced firing and depolarized threshold for action potential (AP), indicating impaired activity. Nevertheless, Hm1a induced a similar AP threshold hyperpolarization in WT and DS interneurons. Conversely, a smaller effect of Hm1a was observed in CA1 pyramidal neurons of DS mice. In these excitatory cells, Hm1a application resulted in WT-specific AP threshold hyperpolarization and increased firing probability, with no effect on DS neurons. Additionally, when the firing of SO interneurons was triggered by CA3 stimulation and relayed via activation of CA1 excitatory neurons, the firing probability was similar in WT and DS interneurons, also featuring a comparable increase in the firing probability following Hm1a application. Interestingly, a similar functional response to Hm1a was observed in a second DS mouse model, harboring the nonsense Scn1aR613X mutation. Furthermore, we show homeostatic synaptic alterations in both CA1 pyramidal neurons and SO interneurons, consistent with reduced excitation and inhibition onto CA1 pyramidal neurons and increased release probability in the CA1-SO synapse. Together, these results suggest global neuronal alterations within the CA1 microcircuit extending beyond the direct impact of NaV1.1 dysfunction.

Ameliorating Effect of Umbilical Cord Mesenchymal Stem Cells in a Human Induced Pluripotent Stem Cell Model of Dravet Syndrome.

Dravet syndrome (DS) is a form of severe childhood-onset refractory epilepsy typically caused by a heterozygous loss-of-function mutation. DS patient-derived induced pluripotent stem cells (iPSCs) are appropriate human cells for exploring disease mechanisms and testing new therapeutic strategies in vitro. Repeated spontaneous seizures can cause neuroinflammatory reactions and oxidative stress, resulting in neuronal toxicity, neuronal dysfunction, blood-brain barrier disruption, and hippocampal inflammation. Antiepileptic drug therapy does not delay the development of chronic epilepsy. The application of mesenchymal stem cells (MSCs) is one therapeutic strategy for thwarting epilepsy development. This study evaluated the effects of human umbilical cord mesenchymal stem cell-conditioned medium (HUMSC-CM) in a new in vitro model of neurons differentiated from DS patient-derived iPSCs. In the presence of HUMSC-CM, increases in superoxide dismutase 1 (SOD1), superoxide dismutase 2 (SOD2), glutathione peroxidase (GPX), and glutathione (GSH) levels were found to contribute to a reduction in reactive oxygen species (ROS) levels. In parallel, inflammation was rescued in DS patient-derived neuronal cells via increased expression of anti-inflammatory cytokines (TGF-β, IL-6, and IL-10) and significant downregulation of tumor necrosis factor-α and interleukin-1β expression. The intracellular calcium concentration ([Ca2+]i) and malondialdehyde (MDA) and ROS levels were decreased in DS patient-derived cells. In addition, action potential (AP) firing ability was enhanced by HUMSC-CM. In conclusion, HUMSC-CM can effectively eliminate ROS, affect migration and neurogenesis, and promote neurons to enter a highly functional state. Therefore, HUMSC-CM is a promising therapeutic strategy for the clinical treatment of refractory epilepsy such as DS.

Establishment of an induced pluripotent stem cell line (ZJSHi001-A) from a patient with epileptic encephalopathy carrying KCNB1 Glu330Asp mutation.

Early infantile epileptic encephalopathy 26 (EE26) is a form of epileptic encephalopathy, a heterogeneous group of severe childhood-onset epilepsies characterized by refractory seizures, neurodevelopmental impairment, and poor prognosis. A recent study has shown that the KCNB1 gene mutation is associated with EE26; yet, the exact mechanism remains unclear. In this study, we produced an induced pluripotent stem cell line (iPSC) with a heterozygous variant of the KCNB1 gene (c.990G>T, p.Glu330Asp). Induced iPSCs were generated from peripheral blood mononuclear cells (PBMCs) obtained from a female child aged 6 with KCNB1 gene c. 990G>T and p.Glu330Asp heterozygous mutation.

Developmental alterations in firing properties of hippocampal CA1 inhibitory and excitatory neurons in a mouse model of Dravet syndrome

Dravet syndrome (Dravet) is a rare, severe childhood-onset epilepsy, caused by heterozygous de novo mutations in the SCN1A gene, encoding for the alpha subunit of the voltage-gated sodium channel, NaV1.1. The neuronal basis of Dravet is debated, with evidence favoring reduced function of inhibitory neurons, that might be transient, or enhanced activity of excitatory cells. Here, we utilized Dravet mice to trace developmental changes in the hippocampal CA1 circuit, examining the properties of CA1 horizontal stratum-oriens (SO) interneurons and pyramidal neurons, through the pre-epileptic, severe and stabilization stages of Dravet. Our data indicate that reduced function of SO interneurons persists from the pre-epileptic through the stabilization stages, with the greatest functional impairment observed during the severe stage. In contrast, opposing changes were detected in CA1 excitatory neurons, with a transient increase in their excitability during the pre-epileptic stage, followed by reduced excitability at the severe stage. Interestingly, alterations in the function of both inhibitory and excitatory neurons were more pronounced when the firing was evoked by synaptic stimulation, implying that loss of function of NaV1.1 may also affect somatodendritic functions. These results suggest a complex pathophysiological mechanism and indicate that the developmental trajectory of this disease is governed by reciprocal functional changes in both excitatory and inhibitory neurons.

SCN3A-Related Neurodevelopmental Disorder: A Spectrum of Epilepsy and Brain Malformation.

Pathogenic variants in SCN3A, encoding the voltage-gated sodium channel subunit Nav1.3, cause severe childhood onset epilepsy and malformation of cortical development. Here, we define the spectrum of clinical, genetic, and neuroimaging features of SCN3A-related neurodevelopmental disorder. Patients were ascertained via an international collaborative network. We compared sodium channels containing wild-type versus variant Nav1.3 subunits coexpressed with β1 and β2 subunits using whole-cell voltage clamp electrophysiological recordings in a heterologous mammalian system (HEK-293T cells). Of 22 patients with pathogenic SCN3A variants, most had treatment-resistant epilepsy beginning in the first year of life (16/21, 76%; median onset, 2 weeks), with severe or profound developmental delay (15/20, 75%). Many, but not all (15/19, 79%), exhibited malformations of cortical development. Pathogenic variants clustered in transmembrane segments 4 to 6 of domains II to IV. Most pathogenic missense variants tested (10/11, 91%) displayed gain of channel function, with increased persistent current and/or a leftward shift in the voltage dependence of activation, and all variants associated with malformation of cortical development exhibited gain of channel function. One variant (p.Ile1468Arg) exhibited mixed effects, with gain and partial loss of function. Two variants demonstrated loss of channel function. Our study defines SCN3A-related neurodevelopmental disorder along a spectrum of severity, but typically including epilepsy and severe or profound developmental delay/intellectual disability. Malformations of cortical development are a characteristic feature of this unusual channelopathy syndrome, present in >75% of affected individuals. Gain of function at the channel level in developing neurons is likely an important mechanism of disease pathogenesis. ANN NEUROL 2020;88:348-362.

Both gain-of-function and loss-of-function de novo CACNA1A mutations cause severe developmental epileptic encephalopathies in the spectrum of Lennox-Gastaut syndrome.

Developmental epileptic encephalopathies (DEEs) are genetically heterogeneous severe childhood-onset epilepsies with developmental delay or cognitive deficits. In this study, we explored the pathogenic mechanisms of DEE-associated de novo mutations in the CACNA1A gene. We studied the functional impact of four de novo DEE-associated CACNA1A mutations, including the previously described p.A713T variant and three novel variants (p.V1396M, p.G230V, and p.I1357S). Mutant cDNAs were expressed in HEK293 cells, and whole-cell voltage-clamp recordings were conducted to test the impacts on CaV 2.1 channel function. Channel localization and structure were assessed with immunofluorescence microscopy and three-dimensional (3D) modeling. We find that the G230V and I1357S mutations result in loss-of-function effects with reduced whole-cell current densities and decreased channel expression at the cell membrane. By contrast, the A713T and V1396M variants resulted in gain-of-function effects with increased whole-cell currents and facilitated current activation (hyperpolarized shift). The A713T variant also resulted in slower current decay. 3D modeling predicts conformational changes favoring channel opening for A713T and V1396M. Our findings suggest that both gain-of-function and loss-of-function CACNA1A mutations are associated with similarly severe DEEs and that functional validation is required to clarify the underlying molecular mechanisms and to guide therapies.

Time of Day and a Ketogenic Diet Influence Susceptibility to SUDEP in Scn1a R1407X/+ Mice.

Sudden unexpected death in epilepsy (SUDEP) is a major cause of mortality in patients with drug-resistant epilepsy. Most SUDEP cases occur in bed at night and are preceded by a generalized tonic-clonic seizure (GTCS). Dravet syndrome (DS) is a severe childhood-onset epilepsy commonly caused by mutations in the SCN1A gene. Affected individuals suffer from refractory seizures and an increased risk of SUDEP. Here, we demonstrate that mice with the Scn1aR1407X/+ loss-of-function mutation (DS) experience more spontaneous seizures and SUDEP during the early night. We also evaluate effects of long-term ketogenic diet (KD) treatment on mortality and seizure frequency. DS mice showed high premature mortality (44% survival by P60) that was associated with increased spontaneous GTCSs 1–2 days prior to SUDEP. KD treated mice had a significant reduction in mortality (86% survival by P60) compared to mice fed a control diet. Interestingly, increased survival was not associated with a decrease in seizure frequency. Further studies are needed to determine how KD confers protection from SUDEP. Moreover, our findings implicate time of day as a factor influencing the occurrence of seizures and SUDEP. DS mice, though nocturnal, are more likely to have SUDEP at night, suggesting that the increased incidence of SUDEP at night in may not be solely due to sleep.

The direct cost of seizure events in severe childhood-onset epilepsies: A retrospective claims-based analysis

ObjectiveThe objective of the study was to assess the direct cost of medically treated seizure events in severe childhood-onset epilepsies. Lennox–Gastaut syndrome (LGS), Dravet syndrome (DS), and tuberous sclerosis complex (TSC) are representative conditions associated with frequent intractable seizures. MethodsCommercial and Medicaid insurance claims from 2010 to 2015 were queried to identify patients with possible LGS, possible DS, or TSC, having ≥2 years of continuous insurance from the date of first epilepsy/seizure diagnosis or antiepileptic drug (AED) fill (index date). Utilization and cost data in patients with and without seizure events requiring acute treatment were evaluated for two years postindex. Medically treated seizure events resulting in minor, moderate, severe, and no injury were included. Average costs were normalized to 2017 dollars at 3% per annum and reported for each cohort, by insurance type and degree of injury. ResultsAmong 9754 patients, 55.4–58.8% of LGS, 47.7–55.8% of DS, and 13.7–28.0% of TSC cohorts had ≥1 medically treated seizure event, depending on insurance type. Events during two-year postindex averaged 2.8–3.3 in LGS, 3.1–3.3 in DS, and 1.9–2.2 in TSC; cost per event averaged $8147–$14,759 in LGS, $4637–$8751 in DS, and $5335–$9672 in TSC. In patients with events, average all-cause costs per-patient-per-year (PPPY) were $71,512–$84,939 in LGS; $31,278–$43,758 in DS; and $42,997–$48,330 in TSC. ConclusionsPatients with intractable seizures having at least one medically treated seizure event incur substantial all-cause costs. Our results can be used to inform cost effectiveness and budget impact models to estimate the value of existing and future treatments for these and similar conditions.

Dravet Syndrome: A Developmental and Epileptic Encephalopathy.

Selective Nav1.1 Activation Rescues Dravet Syndrome Mice From Seizures and Premature Death Richards KL, Milligan CJ, Richardson RJ, Jancovski N, Grunnet M, Jacobson LH, Undheim EAB, Mobli M, Chow CY, Herzig V, Csoti A, Panyi G, Reid CA, King GF, Petrou S. PNAS. 2018;115:E8077-E8085. doi:10.1073/pnas.1804764115Dravet syndrome is a catastrophic, pharmaco-resistant epileptic encephalopathy. Disease onset occurs in the first year of life, followed by developmental delay with cognitive and behavioral dysfunction and substantially elevated risk of premature death. The majority of affected individuals harbor a loss-of-function mutation in one allele ofSCN1A, which encodes the voltage-gated sodium channel Nav1.1. Brain Nav1.1 is primarily localized to fast-spiking inhibitory interneurons; thus, the mechanism of epileptogenesis in Dravet syndrome is hypothesized to be reduced inhibitory neurotransmission leading to brain hyperexcitability. We show that selective activation of Nav1.1 by venom peptide Hm1a restores the function of inhibitory interneurons from Dravet syndrome mice without affecting the firing of excitatory neurons. Intracerebroventricular infusion of Hm1a rescues Dravet syndrome mice from seizures and premature death. This precision medicine approach, which specifically targets the molecular deficit in Dravet syndrome, presents an opportunity for treatment of this intractable epilepsy. A Transient Developmental Window of Fast-Spiking Interneuron Dysfunction in a Mouse Model of Dravet Syndrome Favero M, Sotuyo NP, Lopez E, Kearney JA, Goldberg EM. J Neurosci. 2018;38:7912-7927. doi:10.1523/JNEUROSCI.0193-18.2018Dravet syndrome is a severe childhood-onset epilepsy largely due to heterozygous loss-of-function mutation of the gene SCN1A, which encodes the type 1 neuronal voltage-gated sodium (Na+) channel α subunit Nav1.1. Prior studies in mouse models of Dravet syndrome (Scn1a+/− mice) indicate that, in cerebral cortex, Nav1.1 is predominantly expressed in GABAergic interneurons, in particular in parvalbumin-positive fast-spiking basket cell interneurons (PVINs). This has led to a model of Dravet syndrome pathogenesis in which Nav1.1 mutation leads to preferential dysfunction of interneurons, decreased synaptic inhibition, hyperexcitability, and epilepsy. However, such studies have been implemented at early developmental time points. Here, we performed electrophysiological recordings in acute brain slices prepared from male and female Scn1a+/−mice as well as age-matched wild-type littermate controls and found that, later in development, the excitability of PVINs had normalized. Analysis of action potential waveforms indirectly suggests a reorganization of axonal Na+ channels in PVINs from Scn1a+/− mice, a finding supported by immunohistochemical data showing elongation of the axon initial segment. Our results imply that transient impairment of action potential generation by PVINs may contribute to the initial appearance of epilepsy, but is not the mechanism of ongoing, chronic epilepsy in Dravet syndrome. Significance Statement: Dravet syndrome is characterized by normal early development, temperature-sensitive seizures in infancy, progression to treatment-resistant epilepsy, developmental delay, autism, and sudden unexplained death due to mutation in SCN1A encoding the Na+ channel subunit Nav1.1. Prior work has revealed a preferential impact of Nav1.1 loss on the function of GABAergic inhibitory interneurons. However, such data derive exclusively from recordings of neurons in young Scn1a+/− mice. Here, we show that impaired action potential generation observed in parvalbumin-positive fast-spiking interneurons (PVINs) in Scn1a+/− mice during early development has normalized by postnatal day 35. This work suggests that a transient impairment of PVINs contributes to epilepsy onset, but is not the mechanism of ongoing, chronic epilepsy in Dravet syndrome.

Open-label use of highly purified CBD (Epidiolex®) in patients with CDKL5 deficiency disorder and Aicardi, Dup15q, and Doose syndromes

ObjectiveWe studied our collective open-label, compassionate use experience in using cannabidiol (CBD) to treat epilepsy in patients with CDKL5 deficiency disorder and Aicardi, Doose, and Dup15q syndromes. MethodsWe included patients aged 1–30 years with severe childhood-onset epilepsy who received CBD for ≥10 weeks as part of multiple investigator-initiated expanded access or state access programs for a compassionate prospective interventional study: CDKL5 deficiency disorder (n = 20), Aicardi syndrome (n = 19), Dup15q syndrome (n = 8), and Doose syndrome (n = 8). These patients were treated at 11 institutions from January 2014 to December 2016. ResultsThe percent change in median convulsive seizure frequency for all patients taking CBD in the efficacy group decreased from baseline [n = 46] to week 12 (51.4% [n = 35], interquartile range (IQR): 9–85%) and week 48 (59.1% [n = 27], IQR: 14–86%). There was a significant difference between the percent changes in monthly convulsive seizure frequency during baseline and week 12, χ2(2) = 22.9, p = 0.00001, with no difference in seizure percent change between weeks 12 and 48. Of the 55 patients in the safety group, 15 (27%) withdrew from extended observation by week 144: 4 due to adverse effects, 9 due to lack of efficacy, 1 withdrew consent, and 1 was lost to follow-up. SignificanceThis open-label drug trial provides class III evidence for the long-term safety and efficacy of CBD administration in patients with treatment-resistant epilepsy (TRE) associated with CDKL5 deficiency disorder and Aicardi, Dup15q, and Doose syndromes. Adjuvant therapy with CBD showed similar safety and efficacy for these four syndromes as reported in a diverse population of TRE etiologies. This study extended analysis of the prior report from 12 weeks to 48 weeks of efficacy data and suggested that placebo-controlled randomized trials should be conducted to formally assess the safety and efficacy of CBD in these epileptic encephalopathies.

De novo GABRG2 mutations associated with epileptic encephalopathies.

Epileptic encephalopathies are a devastating group of severe childhood onset epilepsies with medication-resistant seizures and poor developmental outcomes. Many epileptic encephalopathies have a genetic aetiology and are often associated with de novo mutations in genes mediating synaptic transmission, including GABAA receptor subunit genes. Recently, we performed next generation sequencing on patients with a spectrum of epileptic encephalopathy phenotypes, and we identified five novel (A106T, I107T, P282S, R323W and F343L) and one known (R323Q) de novo GABRG2 pathogenic variants (mutations) in eight patients. To gain insight into the molecular basis for how these mutations contribute to epileptic encephalopathies, we compared the effects of the mutations on the properties of recombinant α1β2γ2L GABAA receptors transiently expressed in HEK293T cells. Using a combination of patch clamp recording, immunoblotting, confocal imaging and structural modelling, we characterized the effects of these GABRG2 mutations on GABAA receptor biogenesis and channel function. Compared with wild-type α1β2γ2L receptors, GABAA receptors containing a mutant γ2 subunit had reduced cell surface expression with altered subunit stoichiometry or decreased GABA-evoked whole-cell current amplitudes, but with different levels of reduction. While a causal role of these mutations cannot be established directly from these results, the functional analysis together with the genetic information suggests that these GABRG2 variants may be major contributors to the epileptic encephalopathy phenotypes. Our study further expands the GABRG2 phenotypic spectrum and supports growing evidence that defects in GABAergic neurotransmission participate in the pathogenesis of genetic epilepsies including epileptic encephalopathies.

Palliative epilepsy surgery in Dravet syndrome-case series and review of the literature.

Dravet syndrome (DS), also known as severe myoclonic epilepsy of infancy (SMEI), is a rare genetic disorder that results in severe childhood-onset epilepsy. Children with DS initially present with seizures in the first year of life that are often associated with fevers. With age, multiple seizure types develop. There are few reports and no guidelines regarding palliative surgical treatment for DS. Therefore, we reviewed our surgical experience with DS. We conducted a retrospective review of all patients with genetically confirmed DS who underwent either vagal nerve stimulator (VNS) implantation or corpus callosotomy (CC) from May 2001 to April 2014 at our institution. All inpatient and outpatient relevant documentation were reviewed. Demographic information, genetic mutation, operation performed, and preoperative and postoperative seizure frequency were recorded. Inclusion criteria required greater than one-year postoperative follow-up. Seven children with DS were assessed. Six patients were treated with VNS and one patient was treated with CC. In one child, VNS was followed by CC as a secondary procedure. Therefore, in total, eight surgeries were performed on seven patients during the study period. At least 1year elapsed from presentation to our hospital and surgery for all patients. Average time after the first seizure to VNS was 4.1years, and the average time after the first seizure to CC was 7.6years. The mean age of patients undergoing VNS implantation was 4.3years, and the mean age for patients undergoing CC was eight. Average follow-up for all seven patients was 6.6years. Seizures were decreased in five of the six patients with VNS and decreased in the two patients after CC. Four of the six patients who had VNS implanted had a greater than 50% reduction in seizure frequency, and one of the six patients who had VNS implanted had a less than 50% reduction in seizure frequency. One patient did not respond effectively to the VNS and had very limited change in seizure frequency. Both patients who had a CC had a greater than 50% reduction in seizure frequency. Both VNS and CC in patients with DS can be effective at reducing seizure frequency. Patients with DS may benefit from earlier and more aggressive surgical intervention. Studies using larger patient cohorts will help clarify the role that surgery may play in the multidisciplinary approach to controlling seizures in DS. Further studies will help determine the appropriate timing of and type of surgical intervention.

Coping With a Child With Dravet Syndrome: Insights From Families

Dravet syndrome is a truly catastrophic childhood-onset epilepsy. Families are faced with repeated episodes of status epilepticus, intractable seizures, mental handicap, behavior disorders, and a life of dependency; understandably, coping with Dravet syndrome is very difficult. Twenty-four families with a child with Dravet syndrome were interviewed and identified some practical suggestions to improve their daily life. These included inserting an indwelling venous access device, creating a portable microenvironment, writing an emergency department protocol, establishing emergency routines for the family, assigning a parent on call to lessen the effect on siblings, creating personal time to decrease parental stress, finding respite care, and contacting an Internet support group. Unresolved and common issues included transition to adult care, the utility of early diagnosis, and social isolation. These solutions and issues may be helpful to many families with a child with Dravet syndrome and possibly other severe childhood-onset epilepsies.

Long-term use of zonisamide in refractory childhood-onset epilepsy

This open label study examined the long-term efficacy and safety of zonisamide as adjunctive therapy in mentally retarded and multiple-handicapped patients with severe childhood-onset epilepsy. The study included 24 patients (mean age 12.5 years, range 2–40 years) which had different severe epilepsy syndromes (75% focal, 12.5% generalized, 12.5% refractory status epilepticus) refractory to at least 6 (median 10) anti-epileptic drugs. All patients were followed for at least 18 months after beginning of zonisamide treatment. Mean duration of zonisamide therapy was 55 weeks (range 5–168 weeks) and mean maintenance dosage was 7.7 mg/kg/day (range: 4–16 mg/kg/day). The patients received an average of 1.9 (range 1–3) concomitant antiepileptic drugs. The initial response rate defined as a⩾50% reduction of seizure frequency after 8 weeks was 58.3% (14 of 24 patients). Four of 14 initial responders developed loss of efficacy during long-term treatment. The retention rate after 18 months was 41.7% (10 of 24 patients). One patient (4.2%) became completely seizure-free after initiation of zonisamide treatment and remained seizure-free for the entire observation period of 18 months. Overall, zonisamide was well tolerated. Side effects were observed in 46% of patients and were mild to moderate. They mostly occurred during titration and subsided in maintenance dosing. Only in two patients (8.3%) zonisamide therapy was discontinued due to side effects (loss of appetite). No serious side effects were observed. These results are similar to the findings of Japanese studies suggesting that long-term use of adjunctive zonisamide therapy may be beneficial for treating mentally retarded, multiple handicapped patients with highly refractory childhood-onset epilepsy.

Long-term use of Levetiracetam in patients with severe childhood-onset epilepsy

Objective To assess the efficacy and tolerability of Levetiracetam (LEV) in children and adolescents with refractory epilepsy with a special interest in the long-term retention rate. Method One hundred and twenty-nine patients (83 male, 46 female; mean age 10.6 years/range: 6 months–39 years 9 months) were included in a prospective, open-label, add-on trial of LEV for up to 3 years. All patients had severe forms of epilepsy starting before the age of 10 often accompanied by mental retardation. Primary outcome measures were changes in seizure frequency after 6 months on the medication with LEV, with initial responders (>50% seizure reduction). Further objective was the retention rate of LEV therapy after 3 years defined as percentage of patients still taking LEV. Results Thirty-five patients (27.1%) were initial responders of which 5 became seizure free. The average maximum LEV dosage was 39.8 mg/kg/day (range: 6–70 mg/kg/day) with no difference responders vs. no responders. The retention rate for responders after 3 years was 22.5%. The rate of side effects was 39.8% in all patients, with the most frequent side effects being fatigue (12.5%), aggressiveness (7.8%) and gastrointestinal disorders (13.3%). Conclusions Our study in patients with refractory epilepsy suggests that our initial responders were very likely to be still taking LEV after 3 years. We therefore consider treatment with LEV in this special group of patients with refractory epilepsy a promising therapeutic option, because of its favourable tolerance profile, the option of fast titration and the absence of drug interactions.

The long-term use of vigabatrin and lamotrigine in patients with severe childhood onset epilepsy

Our purpose was to compare the initial efficacy and retention at 5 years of lamotrigine (LTG) and vigabatrin (VGB) in patients with severe childhood-onset epilepsies, especially with regard to loss of efficacy. Add-on therapy in 95 young patients with severe epilepsies in a neuropaediatric department was prospectively followed in open label studies for up to 5 years. VGB group: 56 patients (mean age: 11.1 years). LTG group: 39 patients (mean age: 13.6 years). Definition of initial responders: more than 50% reduction in seizure-frequency after 6 weeks of VGB treatment or after 4 months of LTG treatment. Definition of retention at 5 years: percentage of patients still taking LTG or VGB after 5 years. Definition of loss of efficacy: return to the baseline seizure frequency. The results were: VGB group: after 6 weeks 18 of 56 patients (32%) were initial responders. The retention at 5 years was five of 56 patients (8.9%). One patient (1.8%) was still seizure free. A loss of efficacy occurred in 10 of the 18 initial responders, usually within the first 9 months after the initial response. In the LTG group, after 4 months, 11 of 39 patients (28%) were initial responders. The retention at 5 years was 10 of 39 patients (25.6%). Five patients (12.8%) were still seizure free. The rate of adverse events was equal in both groups (41%). All but one occurred within the first 6 months of treatment. Our study in patients with difficult to treat childhood epilepsies suggests that in clinical practice patients were less likely to be discontinued from LTG than from VGB within 5 years, after similiar initial efficacy. This was mainly due to a loss of efficacy in VGB treatment early after initial response.