Early Life Epilepsies are a Comorbidity of Developmental Brain Disorders

FDA Patient-Focused Drug Development Guidances: Considerations for Trial Readiness in Rare Developmental and Epileptic Encephalopathies

Developmental and epileptic encephalopathies (DEE) are rare, often monogenic neurodevelopmental conditions. Most affected individuals have refractory seizures. All have multiple severe impairments which can be as life-limiting as or more limiting than the seizures themselves. Mechanism- and gene-targeted therapies for these individually rare, genetic conditions hold hope for treatment, amelioration of disease expression, and even cure. The near absence of fit-for-purpose (FFP) clinical outcome assessments (COA) to establish the benefits for nonseizure outcomes of these new therapies in clinical trials poses significant challenges to drug development. The Food and Drug Administration Patient-Focused Drug Development guidance series provides direction for how to overcome these challenges and to ensure FFP measures are available for trials. The goal is to have measures that address outcomes of importance to patients and caregivers, reliably and accurately measure the outcome in the spectrum of abilities for the target disease, and are sensitive to meaningful change over time. The guidances identify 3 primary strategies: (1) directly adopting and implementing available outcome measures; (2) creating measures de novo; and (3) a middle path of adapting or modifying existing measures. Emphasized throughout the guidances is the indispensable and extensive role of the patient or caregiver to assuring the goal of having fit measures is achieved. This review specifically considers the difficulties of adopting available COAs in severely impaired patient groups and ways to adapt or modify existing COAs to be FFP as encouraged in the guidances. Adaptations include alternative scoring, use of assessments in out-of-intended age ranges, and modifications for individuals with sensory or motor impairments. Some additional considerations that may facilitate achieving adequate clinical outcome measures, especially for rare diseases, include use of personalized endpoints, merging of existing COAs, and developing a consortium of rare DEE advocates and researchers to ensure fitness of adapted COAs across multiple rare disease groups. The FDA guidances help ensure that clinical trials targeting nonseizure outcomes, especially in severely impaired populations, will have adequately valid and sensitive outcome measures. This in turn will strengthen the ability of trials to provide informative tests of whether treatments provide meaningful therapeutic efficacy.

Patient-advocate-led global coalition adapting fit-for-purpose outcomes measures to assure meaningful inclusion of DEEs in clinical trials

Existing clinical tools that measure non-seizure outcomes lack the range and granularity needed to capture skills in developmental and epileptic encephalopathy (DEE)-affected individuals who also fall in the severe to profound range of intellectual disability. This effectively excludes those with severe impairments from clinical trials, impeding the ability of sponsors to evaluate disease-modifying therapies (DMTs). The Inchstone Project, an international, patient advocate-led collaboration, brings together leading researchers, clinicians, pharmaceutical companies, and advocates to develop an adapted, validated assessment battery within 5 years. The goal is to support trials of DMTs for the DEEs by providing sufficiently sensitive measurement tools to demonstrate therapeutic efficacy. An initial pilot study administered 7 established assessments to 10 individuals affected by SCN2A-DEE, identifying specific limitations of existing measures and areas for improvement. It was clear that most tools do not account for challenges throughout the DEE population, including vision impairments, significant motor impairments and profound intellectual disability, which need to be accounted for in creating a 'fit-for-purpose' battery for the DEE population. Several novel assessments, including two measures of responsivity developed for use in monitoring recovery after acquired brain injury as well as individualized Goal Attainment Scaling, showed promise in this group. The team also completed a DEE-wide survey with over 270 caregivers documenting their children's abilities and priorities for their improvement from new treatments. The Inchstone team is using this information to evaluate how existing tools might be updated to better capture what is most important to families and measure their child's small but important improvements over time. These efforts are building a coherent picture across multiple DEEs of what domains, or concepts of interest, have the greatest impact on most patients and families. The Inchstone team is on course to adapt non-seizure outcome measures that are (1) sufficiently sensitive to measure small increments of meaningful change ('Inchstones') and (2) applicable to multiple DEE conditions.

Before the first seizure: The developmental imprint of infant epilepsy on neurodevelopment

In light of the heterogeneity of epilepsy, both from a clinical and from an etiological perspective, it is difficult to establish a link between epilepsy and development that can be generalized to all infantile epilepsies. In general however, early-onset epilepsy has a poor developmental prognosis that is significantly linked to several parameters: age at first seizure, drug resistance, treatment, and etiology. This paper discusses the relationship between visible epilepsy parameters (those that allow the diagnosis of epilepsy) and neurodevelopment in infants, with special focus on Dravet syndrome and KCNQ2-related epilepsy, two common developmental and epileptic encephalopathies; and focal epilepsy caused by focal cortical dysplasia, which often begins during infancy. There are a number of reasons why it is difficult to dissect the relationship between seizures and their causes, and we suggest a conceptual model in which epilepsy is a neurodevelopmental disorder whose severity is determined by how the disease imprints itself on the developmental process rather than by the symptoms or etiology. The precocity of this developmental imprint may explain why treating seizures once they occur can have a very slight beneficial effect on development.

Insulin-Like Growth Factor-1 Promotes Synaptogenesis Signaling, a Major Dysregulated Pathway in Malformation of Cortical Development, in a Rat Model

Malformation of cortical development (MCD) is one of the main causes of intractable epilepsy in childhood. We explored a treatment based on molecular changes using an infant rat model of methylazoxymethanol (MAM)-induced MCD established by injecting MAM at gestational day 15. The offspring were sacrificed on postnatal day (P) 15 for proteomic analysis, which revealed significant downregulation in the synaptogenesis signaling pathway in the cortex of MCD rats. Recombinant human insulin-growth factor-1 (rhIGF-1) was injected from P12 to P14 twice daily and the effect of IGF1 on N-methyl-D-aspartate (NMDA)-induced spasms (15 mg/kg of NMDA, i.p.) was tested; the onset of P15 single spasm was significantly delayed (p = 0.002) and the number of spasms decreased (p < 0.001) in rhIGF1-pretreated rats (n = 17) compared to those in VEH-treated rats (n = 18). Electroencephalographic monitoring during spasms showed significantly reduced spectral entropy and event-related spectral dynamics of fast oscillation in rhIGF-1 treated rats. Magnetic resonance spectroscopy of the retrosplenial cortex showed decreased glutathione (GSH) (p = 0.039) and significant developmental changes in GSH, phosphocreatine (PCr), and total creatine (tCr) (p = 0.023, 0.042, 0.015, respectively) after rhIGF1 pretreatment. rhIGF1 pretreatment significantly upregulated expression of cortical synaptic proteins such as PSD95, AMPAR1, AMPAR4, NMDAR1, and NMDAR2A (p < 0.05). Thus, early rhIGF-1 treatment could promote synaptic protein expression, which was significantly downregulated by prenatal MAM exposure, and effectively suppress NMDA-induced spasms. Early IGF1 treatment should be further investigated as a therapeutic strategy in infants with MCD-related epilepsy.

Cognitive disorders in childhood epilepsy: a comparative longitudinal study using administrative healthcare data

OBJECTIVE

The study aimed to assess the risk of cognitive impairment in patients with epilepsy, the impact of age of epilepsy onset on cognition and the temporal relationship of epilepsy onset and intellectual impairment.

METHODS

This longitudinal study analyzed birth cohorts and followed-up children born 2005-2007 up to the age of ten using administrative healthcare data of about 8.9 million members insured by the statutory health insurance "BARMER" in Germany. We compared prevalence of cognitive impairment (ICD-code F7*) in children with epilepsy (ICD-code G40) to controls, and calculated relative risks by age groups at onset of epilepsy and assessed differences in relation to the temporal sequence of the diagnoses.

RESULTS

Of the 142,563 pre-pubertal children included in the analysis, 2728 (1.9%) had an epilepsy diagnosis within the first 10 years of life. 17.4% (475/2728) of children with epilepsy had a diagnosis of cognitive impairment compared to 1.7% (2309/139835) in controls. The relative risk for cognitive impairment compared to age-matched controls was 10.5 (95% CI 9.6, 11.6) and was highest in epilepsy cases with seizure manifestation within the first 2 years of life compared to older children. The prevalence of cognitive impairment before epilepsy diagnosis was slightly increased compared to controls, while it was increased by a factor of nine in children diagnosed with cognitive impairment in the year of onset of epilepsy or afterwards.

CONCLUSIONS

Pre-pubertal children with epilepsy have a ten-fold higher risk for intellectual impairment compared to age-matched controls. This risk inversely correlates with the age of epilepsy manifestation. Cognitive impairment was diagnosed after epilepsy manifestation in the majority of patients.

Sensory Processing Difficulties in Patients with Functional Neurological Disorder: Occupational Therapy Management Strategies and Two Cases

Functional neurological disorder (FND) is a condition at the intersection of neurology and psychiatry, with some patients experiencing sensory hypersensitivities and other sensory processing difficulties. It has been postulated that poor integration and modulation of sensory information with cognitive, affective and behavioral processes may play a role in the pathophysiology of FND. In this article, we first succinctly review the role for occupational therapy (OT) in the multidisciplinary therapeutic approach to managing patients with FND. After highlighting previously published data identifying sensory processing difficulties in patients with FND, we subsequently outline the components of the sensory-based outpatient OT program for FND at the Massachusetts General Hospital. Here, we detail how occupational therapists assess and treat sensory modulation difficulties with the aid of resources like the Adolescent/Adult Sensory Profile (AASP), The Canadian Occupational Performance Measure (COPM), and the Sensory-Motor Preference Checklist. We then report on 2 clinical cases representative of the sensory modulation difficulties endorsed by some patients with FND, illustrating how developing an individualized, sensory-based treatment plan can help improve functional neurological symptoms and overall participation in activities of daily living. Prospective, controlled research is needed to further operationalize OT-based sensory modulation interventions, as well as define the tolerability and efficacy of this intervention for pediatric and adult populations with FND.

Rare diseases - rare outcomes: Assessing communication abilities for the developmental and epileptic encephalopathies

OBJECTIVE

Developmental and epileptic encephalopathies (DEE) entail moderate to profound communication and other impairments that are poorly measured by typical clinical outcomes assessments (COA). We examined the potential of alternative approaches, specifically, the use of raw scores and COAs outside of their intended age ranges.

METHODS

In a cross-sectional survey, 120 parents of children with Dravet Syndrome, Lennox-Gastaut syndrome, KCNQ2-DEE, KCNB1-DEE, and SCN2A-DEE (ages 1-35 years) completed the Adaptive Behavior Assessment System-3 for ages 0-5 years, modified checklist for autism (mCHAT), communication and social behavior scales (CSBS), communication matrix (CM), and several parent-reported classifiers of communication. Adaptive Behavior Assessment System communication and social raw scores were the primary and adjunctive outcomes. Floor and ceiling effects, dispersion and convergence with related measures were assessed with appropriate parametric and nonparametric statistical techniques.

RESULTS

Median chronological age (CA) was 8.7 years (Interquartile range (IQR): 5.3-13.5). Adaptive Behavior Assessment Systemcommunication and social age equivalents were 12.5 months (IQR 7.5-28) and 16.5 months (IQR 9-31). Most raw scores corresponded to standardized scores indicating performance <3 standard deviations below the general population mean. Adaptive Behavior Assessment System raw scores demonstrated minimal floor and ceiling effects (<1-2.5%). In linear regression models, scores correlated with age under 6 years (communication, p = 0.001; social, p = 0.003) but significantly flattened out thereafter. Scores varied substantially by DEE group (both p < 0.001) and decreased with higher convulsive seizure frequency (communication, p = 0.01, social, p = 0.02). There was good convergence with mCHAT, CSBS, and CM scores (all r > 0.8).

SIGNIFICANCE

Raw scores and out-of-range COAs may provide measures that are sensitive at the very limited levels of functioning typical of profoundly impaired, older patients with DEEs. To ensure that targeted trial outcomes are responsive to meaningful change, development of these approaches will be essential to clinical trial readiness for novel therapies for rare DEEs.

Dysautonomia and functional impairment in rare developmental and epileptic encephalopathies: the other nervous system

AIM

To determine whether functional impairments and autonomic symptoms are correlated in young people with developmental and epileptic encephalopathies (DEEs).

METHOD

Cross-sectional, online surveys (2018-2020) of parents recruited from family groups obtained information on several aspects of children's conditions including functional abilities (mobility, hand use, eating, and communication), 18 autonomic symptoms in six groups (cardiac, respiratory, sweating, temperature, gastrointestinal, and other), and parental stress. Bivariate and multivariable logistic regression analyses examined associations of dysautonomias with functional impairment, adjusted for type of DEE and age.

RESULTS

Of 313 participants with full information on function and dysautonomias, 156 (50%) were females. The median age was 8 years (interquartile range 4-12y); 255 (81%) participants had symptoms in at least one autonomic symptom group; 283 (90%) had impairment in at least one functional domain. The number of functional impairment domains and of autonomic symptom groups varied significantly across DEE groups (both p<0.001). The number of functional impairment domains and of autonomic symptom groups were correlated (Spearman's r=0.35, p<0.001) on bivariate and multivariable analysis adjusted for DEE group and age. Parental stress was also independently correlated with dysautonomias (p<0.001).

INTERPRETATION

Parent-reported dysautonomias are common in children with DEEs. They correlate with extent of functional impairment and may contribute to caregiver stress. What this paper adds Dysautonomic symptoms are common in young people with developmental and epileptic encephalopathies (DEEs). Burden of dysautonomias is strongly correlated with burden of functional impairments. Aspects of dysautonomic function may provide biomarkers of DEE disease severity.

Gastrointestinal Symptoms and Channelopathy-Associated Epilepsy

OBJECTIVE

To determine the prevalence of and identify factors associated with gastrointestinal (GI) symptoms among children with channelopathy-associated developmental and epileptic encephalopathy (DEE).

STUDY DESIGN

Parents of 168 children with DEEs linked to SCN1A (n = 59), KCNB1 (n = 31), or KCNQ2 (n = 78) completed online CLIRINX surveys about their children's GI symptoms. Our analysis examined the prevalence, frequency, and severity of GI symptoms, as well as DEE type, functional mobility, feeding difficulties, ketogenic diet, antiseizure medication, autism spectrum disorder (ASD), and seizures. Statistical analyses included the χ² test, Wilcoxon rank-sum analysis, and multiple logistic regression.

RESULTS

GI symptoms were reported in 92 of 168 patients (55%), among whom 63 of 86 (73%) reported daily or weekly symptoms, 29 of 92 (32%) had frequent or serious discomfort, and 13 of 91 (14%) had frequent or serious appetite disturbances as a result. The prevalence of GI symptoms varied across DEE cohorts with 44% of SCN1A-DEE patients, 35% of KCNB1-DEE patients, and 71% of KCNQ2-DEE patients reporting GI symptoms in the previous month. After adjustment for DEE type, current use of ketogenic diet (6% reported), and gastrostomy tube (13% reported) were both associated with GI symptoms in a statistically, but not clinically, significant manner (P < .05). Patient age, functional mobility, feeding difficulties, ASD, and seizures were not clearly associated with GI symptoms. Overall, no individual antiseizure medication was significantly associated with GI symptoms across all DEE cohorts.

CONCLUSIONS

GI symptoms are common and frequently severe in patients with DEE.

Cognitive performance and behavior across idiopathic/genetic epilepsies in children and adolescents

We investigated the cognitive and behavioral profile of three distinct groups of epilepsies with a genetic background for intergroup differences: (1) idiopathic/genetic generalized epilepsies (IGE/GGE group); (2) idiopathic focal epilepsies (IFE group); and (3) epilepsies with proven or strongly suggested monogenic or structural/numeric chromosomal etiology (genetic epilepsies, GE group). Cognitive (total IQ and subcategories) and behavioral parameters (CBCL) were assessed at the tertiary epilepsy center of the University of Munich (Germany). We used ANOVA with post-hoc Bonferroni-correction to explore significant mean differences and Fisher’s exact test for significant proportional differences of intelligence impairment and behavioral problems. 126 (56 IGE/GGE, 26 IFE, 44 GE) patients were available. Total IQ was 89.0 ± 15.9 (95% CI 84.5–93.4) for IGE/GGE, 94.8 ± 18.1 (95% CI 87.3–102.3) for IFE and 76.4 ± 22.4 (95% CI 67.6–85.3) for GE (p = 0.001). The same trend was significant for all but one IQ subcategory. The rate of patients with an intelligence impairment (total IQ < 70) was higher for GE (40%) than for IGE/GGE (14%) and for IFE (7%) patients (p = 0.033). There were no significant differences between groups for behavior scores and behavioral problems. This study shows that the current ILAE classification of epilepsies with genetic etiology creates a heterogeneous group of patients with respect to cognitive performance but not behavior. These findings may help in further delineating epilepsies as regards cognitive performance, notwithstanding their closely related etiological classification.

The vulnerability of the immature brain

The concept of vulnerability of the immature brain is multifactorial by definition. Newer scientific work in this area has shifted and enlarged the concept from theoretical frameworks to the multiple levels (molecular, cellular, anatomic, network, behavioral) of the organization of the growing brain. The concept of vulnerability was first introduced by Donald O. Hebb in the 1950s and referred to the inability of the immature brain to completely recover normal development after a brain insult. The concept of vulnerability was further extended to the limitations of the brain in the development of specific skills in neuronal substrates originally used for other functions. We present an overview of some neurodevelopmental processes that characterize the immature brain and that can predict vulnerability in the case of disturbances: Hebb's principle, synaptic homeostasis, selective vulnerability of immature cells in mammals, and inherited constraint networks. A better understanding of the vulnerability mechanisms may help in early detection and prevention and further proposed individualized therapeutic approaches to enhance children's developmental outcomes.

A novel GABRB3 variant in Dravet syndrome: Case report and literature review

Background

Mutations in GABRB3 have been identified in subjects with different types of epilepsy and epileptic syndromes, including West syndrome (WS), Dravet syndrome (DS), Lennox‐Gastaut syndrome (LGS), myoclonic‐atonic epilepsy (MAE), and others.

Methods and results

We herewith report on a girl affected by DS, who has been followed from infancy to the current age of 18 years. Next‐generation sequencing (NGS)‐based genetic testing for multigene analysis of neurodevelopmental disorders identified two likely de novo pathogenic mutations, a missense variant in GABRB3 gene (c.842 C>T; p.Thr281IIe) and a nonsense variant found in BBS4 gene (c.883 C>T; p.Arg295Ter).

Conclusion

A likely relationship between the novel GABRB3 gene variant and the clinical manifestations presented by the girl is proposed. Previously, one case of DS and two of DS‐like linked with GABRB3 mutations have been reported. To the best of our knowledge, this is the first report of DS associated with this novel variant. A literature review of clinical cases with various types of epileptic encephalopathies (EEs) related to GABRB3 mutations is reported.

Our study explores a likely new gene‐phenotype relationship between a novel GABRB3 gene variant and the clinical manifestations of Dravet syndrome (DS). We, herewith, report on a long‐term follow‐up of a girl affected by DS, who harbors a novel likely pathogenic variant of GABRB3. A literature review of cases with various types of epileptic encephalopathy related to GABRB3 mutations is discussed.

Fine Spike Timing in Hippocampal-Prefrontal Ensembles Predicts Poor Encoding and Underlies Behavioral Performance in Healthy and Malformed Brains

Spatial working memory (SWM) is a central cognitive process during which the hippocampus and prefrontal cortex (PFC) encode and maintain spatial information for subsequent decision-making. This occurs in the context of ongoing computations relating to spatial position, recall of long-term memory, attention, among many others. To establish how intermittently presented information is integrated with ongoing computations we recorded single units, simultaneously in hippocampus and PFC, in control rats and those with a brain malformation during performance of an SWM task. Neurons that encode intermittent task parameters are also well modulated in time and incorporated into a functional network across regions. Neurons from animals with cortical malformation are poorly modulated in time, less likely to encode task parameters, and less likely to be integrated into a functional network. Our results implicate a model in which ongoing oscillatory coordination among neurons in the hippocampal-PFC network describes a functional network that is poised to receive sensory inputs that are then integrated and multiplexed as working memory. The background temporal modulation is systematically altered in disease, but the relationship between these dynamics and behaviorally relevant firing is maintained, thereby providing potential targets for stimulation-based therapies.

Epilepsy

Epilepsy is considered a disease characterized by an underlying predisposition to seizures as well as neurobiologic, cognitive, psychologic, and social consequences. It is the most frequent chronic neurologic condition of childhood, affecting 0.5%-1% of children worldwide. It comprises a variety of disorders with many different etiologies, consequently affecting management and outcome. Although the great majority of children have epilepsies that are self-limited and have a good prognosis, it is nevertheless very well recognized that epileptic activity (be it seizures or interictal discharges) can be particularly deleterious to the developing brain acting as a disruptor to normal developmental function. Indeed, epilepsy and neurocognitive and behavioral disorders very frequently coexist, and it can be challenging to understand if there is causality or if they are all the reflection of the underlying brain disorder. Hence, accurate phenotypic and etiologic diagnosis is of utmost importance as it will not only guide decision making with regard to choice of treatment but also enable management of expectations concerning outcome. The current chapter aims to provide a general overview of the fast evolving and vast field of childhood epilepsy from its definition and epidemiology, to its diagnostic challenges, management, and outcome.

Structural neuroimaging

Characterizing the neuroanatomical correlates of brain development is essential in understanding brain-behavior relationships and neurodevelopmental disorders. Advances in brain MRI acquisition protocols and image processing techniques have made it possible to detect and track with great precision anatomical brain development and pediatric neurologic disorders. In this chapter, we provide a brief overview of the modern neuroimaging techniques for pediatric brain development and review key normal brain development studies. Characteristic disorders affecting neurodevelopment in childhood, such as prematurity, attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), epilepsy, and brain cancer, and key neuroanatomical findings are described and then reviewed. Large datasets of typically developing children and children with various neurodevelopmental conditions are now being acquired to help provide the biomarkers of such impairments. While there are still several challenges in imaging brain structures specific to the pediatric populations, such as subject cooperation and tissues contrast variability, considerable imaging research is now being devoted to solving these problems and improving pediatric data analysis.

The involvement of altered sensory modulation in neurological conditions and its relevance to neuro-rehabilitation: a narrative literature review

PURPOSE

Neurological conditions are frequently described and treated with emphasis on primarily body dysfunctions that appear in the diagnostic criteria. This perspective paper aims to provide knowledge about the involvement of secondary body dysfunctions - altered sensory modulation - in neurological conditions and their relevance to neuro-rehabilitation. This paper refers to children and adults, to provide a life span view. Health models and approaches are discussed to bring ideas for optimizing rehabilitation.

METHODS

Perspective based on narrative literature review.

RESULTS

Altered sensory modulation is prevalent in neurological conditions. It is related to clinical symptoms, comorbidities and severity level. Many studies focus on specific modalities and on laboratory/clinical measurements. However, information gathered from subjective measures reflects the alterations in various sensory modalities and their negative impacts on the individuals' daily activity performance, participation and quality of life (QOL).

CONCLUSIONS

Neuro-rehabilitation should consider altered sensory modulation in neurological conditions, apply health models with broad perspective, as the ICF, with multi-disciplinary team, objective and subjective measures to understand how pathogenic mechanisms in primary and secondary body dysfunctions impact the performance and participation in daily life. This approach may optimize the individuals' involvement in therapy, enhance daily function and QOL and elevate intervention success.Implications for rehabilitationSensory modulation should be evaluated in children and adults with neurologic conditions.The evaluation and intervention should refer to the involvement of altered sensory modulation in the conditions' clinical characteristics, severity and comorbidities.In case altered sensory modulation is found, the evaluation and intervention should incorporate a multi-disciplinary collaboration and health models such as the ICF model, to optimize neuro-rehabilitation efficiency.Objective measures should be applied to profile altered sensory modulation and its role in pathogenic mechanisms.Subjective measures should also be used to reflect the expressions of altered sensory modulation as experienced by the individual (and family members), in daily life scenarios.By bridging between the clinic and the individuals' real-life context, rehabilitation process and outcomes may be optimized, in terms of the individual's greater involvement in therapy, better function and quality of life.

Safety and Efficacy of Supratherapeutic Doses of Clobazam

Clobazam is a commonly used long-acting benzodiazepine approved by the US Food and Drug Administration (FDA) to treat seizures associated with Lennox Gastaut syndrome. The FDA approved maximum dosage of clobazam is 1 mg/kg/d or a total of 40 mg a day. Many providers exceed this dosage but there is limited data on the safety, tolerability, and efficacy of supratherapeutic doses. We reviewed retrospective data at our institution and compared patients on supratherapeutic doses to patients on therapeutic doses. A total of 133 patients met inclusion criteria (65 supratherapeutic, 67 therapeutic). There was no statistically significant difference in terms of seizure control, health care utilization, or side effects between patients on supratherapeutic doses and those on therapeutic doses. This study lends further support to the safety and tolerability of supratherapuetic doses of clobazam.

Immediate outcomes in early life epilepsy: A contemporary account

RATIONALE

Early-life epilepsies (ELEs) include some of the most challenging forms of epilepsy to manage. Given recent diagnostic and therapeutic advances, a contemporary assessment of the immediate short-term outcomes can provide a valuable framework for identifying priorities and benchmarks for evaluating quality improvement efforts.

METHODS

Children with newly diagnosed epilepsy and onset <3 years were prospectively recruited through 17 US hospitals, from 2012 to 2015 and followed for 1 year after diagnosis. Short-term outcome included mortality, drug resistance, evolution of nonsyndromic epilepsy to infantile spasms (IS) and from IS to other epilepsies, and developmental decline. Multivariable analyses assessed the risk of each outcome.

RESULTS

Seven hundred seventy-five children were recruited, including 408 (53%) boys. Median age at onset was 7.5 months (interquartile range (IQR): 4.2-16.5), and 509 (66%) had onset in the first year of life. Of 22 deaths that occurred within one year of epilepsy diagnosis, 21 were children with epilepsy onset in infancy (<12 months). Of 680 children followed ≥6 months, 239 (35%) developed drug-resistant seizures; 34/227 (15%) infants with nonsyndromic epilepsy developed IS, and 48/210 (23%) initially presenting with IS developed additional seizure types. One hundred of 435 (23%) with initially typical development or only mild/equivocal delays at seizure onset, had clear developmental impairment within one year after initial diagnosis. Each outcome had a different set of predictors; however, younger age and impaired development at seizure onset were broadly indicative of poorer outcomes. Type of epilepsy and early identification of underlying cause were not reliable predictors of these outcomes.

CONCLUSION

Early-life epilepsies carry a high risk of poor outcome which is evident shortly after epilepsy diagnosis. Onset in infancy and developmental delay is associated with an especially high risk, regardless of epilepsy type. The likelihood of poor outcomes is worrisome regardless of specific clinical profiles.

Molecular basis for and chemogenetic modulation of comorbidities in GABRG2-deficient epilepsies

OBJECTIVE

γ-Aminobutyric acid type A (GABA_A ) receptor subunit gene mutations are significant causes of epilepsy, which are often accompanied by various neuropsychiatric comorbidities, but the underlying mechanisms are unclear. It has been suggested that the comorbidities are caused by seizures, as the comorbidities often present in severe epilepsy syndromes. However, findings from both humans and animal models argue against this conclusion. Mutations in the GABA_A receptor γ2 subunit gene GABRG2 have been associated with anxiety alone or with severe epilepsy syndromes and comorbid anxiety, suggesting that a core molecular defect gives rise to the phenotypic spectrum. Here, we determined the pathophysiology of comorbid anxiety in GABRG2 loss-of-function epilepsy syndromes, identified the central nucleus of the amygdala (CeA) as a primary site for epilepsy comorbid anxiety, and demonstrated a potential rescue of comorbid anxiety via neuromodulation of CeA neurons.

METHODS

We used brain slice recordings, subcellular fractionation with Western blot, immunohistochemistry, confocal microscopy, and a battery of behavior tests in combination with a chemogenetic approach to characterize anxiety and its underlying mechanisms in a Gabrg2^+/Q390X knockin mouse and a Gabrg2^+/- knockout mouse, each associated with a different epilepsy syndrome.

RESULTS

We found that impaired GABAergic neurotransmission in CeA underlies anxiety in epilepsy, which is due to reduced GABA_A receptor subunit expression resulting from the mutations. Impaired GABA_A receptor expression reduced GABAergic neurotransmission in CeA, but not in basolateral amygdala. Activation or inactivation of inhibitory neurons using a chemogenetic approach in CeA alone modulated anxietylike behaviors. Similarly, pharmacological enhancement of GABAergic signaling via γ2 subunit-containing receptors relieved the anxiety.

SIGNIFICANCE

Together, these data demonstrate the molecular basis for a comorbidity of epilepsy, anxiety, and suggest that impaired GABA_A receptor function in CeA due to a loss-of-function mutation could at least contribute to anxiety. Modulation of CeA neurons could cause or suppress anxiety, suggesting a potential use of CeA neurons as therapeutic targets for treatment of anxiety in addition to traditional pharmacological approaches.

Why Malformations of Cortical Development Cause Epilepsy

Malformations of cortical development (MCDs), a complex family of rare disorders, result from alterations of one or combined developmental steps, including progenitors proliferation, neuronal migration and differentiation. They are an important cause of childhood epilepsy and frequently associate cognitive deficits and behavioral alterations. Though the physiopathological mechanisms of epilepsy in MCD patients remain poorly elucidated, research during the past decade highlighted the contribution of some factors that will be reviewed in this paper and that include: (i) the genes that caused the malformation, that can be responsible for a significant reduction of inhibitory cells (e.g., ARX gene) or be inducing cell-autonomous epileptogenic changes in affected neurons (e.g., mutations on the mTOR pathway); (ii) the alteration of cortical networks development induced by the malformation that will also involve adjacent or distal cortical areas apparently sane so that the epileptogenic focus might be more extended that the malformation or even localized at distance from it; (iii) the normal developmental processes that would influence and determine the onset of epilepsy in MCD patients, particularly precocious in most of the cases.

Benign and severe early-life seizures: a round in the first year of life

BACKGROUND

At the onset, differentiation between abnormal non-epileptic movements, and epileptic seizures presenting in early life is difficult as is clinical diagnosis and prognostic evaluation of the various seizure disorders presenting at this age. Seizures starting in the first year of life including the neonatal period might have a favorable course, such as in infants presenting with benign familial neonatal epilepsy, febrile seizures simplex or acute symptomatic seizures. However, in some cases, the onset of seizures at birth or in the first months of life have a dramatic evolution with severe cerebral impairment. Seizure disorders starting in early life include the "epileptic encephalopathies", a group of conditions characterized by drug resistant seizures, delayed developmental skills, and intellective disability. This group of disorders includes early infantile epileptic encephalopathy also known as Ohtahara syndrome, early myoclonic encephalopathy, epilepsy of infancy with migrating focal seizures, infantile spasms syndrome (also known as West syndrome), severe myoclonic epilepsy in infancy (also known as Dravet syndrome) and, myoclonic encephalopathies in non-progressive disorder. Here we report on seizures manifesting in the first year of life including the neonatal period. Conditions with a benign course, and those with severe evolution are presented. At this early age, clinical identification of seizures, distinction of each of these disorders, type of treatment and prognosis is particularly challenging. The aim of this report is to present the clinical manifestations of each of these disorders and provide an updated review of the conditions associated with seizures in the first year of life.

Getting serious about the early-life epilepsies

Early-life epilepsies represent a group of many individually rare and often complex developmental brain disorders associated with lifelong devastating consequences and high risk for early mortality. The quantity and quality of evidence needed to guide the evaluation and treatment to optimize outcomes of affected children is minimal; most children are treated within an evidence-free practice zone based solely on anecdote and lore. The remarkable advances in diagnostics and therapeutics are implemented haphazardly with no systematic effort to understand their effects and value. This stands in stark contrast to the evidence-rich practice of the Children's Oncology Group, where standard of care treatments are identified through rigorous, multicenter research studies, and the vast majority of patients are treated on protocols developed from that research. As a consequence, overall mortality for childhood cancers has declined from ∼90% in the 1950s to ∼20% today. The situations of these 2 rare disease specialties are contrasted, and some suggestions for moving early-life epilepsy onto a fast track for success are offered. Chief amongst these is that early-life epilepsy should be treated with the same urgency as pediatric cancer. The best diagnostics and evidence-based treatments should be used in a systematic fashion right from the start, not after the child and family have been subjected to the ravages of the disorder for months or years. This will require unity and cooperation among physicians, researchers, and institutions across state and national borders.