Sleep abnormalities in children with Dravet syndrome

Sleep and respiratory abnormalities in adults with developmental and epileptic encephalopathies using polysomnography and video-EEG monitoring

This study evaluated sleep and respiratory abnormalities, and their relationship with seizures, in adults with developmental and epileptic encephalopathies (DEEs). We studied consecutive adults with DEEs undergoing inpatient video-EEG monitoring and concurrent polysomnography between December 2011 and July 2022. Thirteen patients with DEEs were included (median age: 31 years, range: 20-50; 69.2% female): Lennox-Gastaut syndrome (n = 6), Lennox-Gastaut syndrome-like phenotype (n = 2), Landau-Kleffner syndrome (n = 1), epilepsy with myoclonic-atonic seizures (n = 1), and unclassified DEEs (n = 3). Sleep architecture was often fragmented by epileptiform discharges and seizures resulting in arousals (median arousal index: 29.0 per h, range: 5.1-65.3). Moderate-to-severe obstructive sleep apnea (OSA) was observed in seven patients (53.8%). Three patients (23.1%) had tonic seizures that frequently occurred with central apnea; one met criteria for mild central sleep apnea. Of the patients with tonic seizures, two had other identifiable seizure manifestations, but in one patient, central apnea was commonly the only discernable seizure manifestation. Polysomnography during video-EEG is an effective diagnostic tool in detecting sleep and seizure-related respiratory abnormalities. Clinically significant OSA may increase the risk of comorbid cardiovascular disease and premature mortality. Treatment of epilepsy may improve sleep quality, and conversely, improved sleep, may decrease seizure burden.

Infra-low frequency neurofeedback training in Dravet syndrome: A case study

This case study examines how an intervention of infra-low frequency neurofeedback training (ILF-NFT) affects the symptomatology of an eight-year-old patient with Dravet syndrome (DS), a rare and highly disabling form of epilepsy. Our results demonstrate that ILF-NFT has improved the patient's sleep disturbance, has significantly reduced seizure frequency and severity, and has reversed neurodevelopmental decline, with positive development in intellectual and motor skills. No significant changes have been made to the patient's medication in the observed period of 2.5 years. Thus, we draw attention to ILF-NFT as a promising intervention in addressing DS symptomatology. Finally, we discuss the study's methodological limitations and warrant future studies to assess the effect of ILF-NFT in DS in more elaborate research designs.

Genetic and clinical variations of developmental epileptic encephalopathies

OBJECTIVE

The concept of 'developmental and epileptic encephalopathy (DEE)' recognises that in infants presenting with severe early-onset epilepsy, neurodevelopmental comorbidity may be attributable to both the underlying cause and to adverse effects of uncontrolled epileptic activity. There is no direct genotype - phenotype correlation in DEEs. This study aimed to report the genetic and phenotypic differences in patients with DEE.

METHODS

Genetic evaluations of the patients were performed due to epilepsy combined with developmental delay, epileptic encephalopathy, motor deficits, autistic features, or cognitive impairment. Patients were assessed for demographic characteristics, medical history, family history, psychomotor development, seizure control interventions, electroencephalogram (EEG) and magnetic resonance imaging (MRI) findings.

RESULTS

This study included 20 children aged 0-16 years who were diagnosed as having DEE.The types of DEE detected in our study were DEE 2, 4, 6B, 7, 11, 26, 30, 33, 35, 42, 58, 62, and 67.Status epilepticus was recorded in only DEE7. The most common EEG abnormality was multifocal epileptic discharges (35%,) followed by burst-suppression patterns in patients with neonatal-onset seizures. Thirteen of the children were aged over 2 years, two (15%) were non-ambulatory and six (46%) were non-verbal. MRI scans were normal in 80% of the patients. Refractory epilepsy seen in 33% of cases.De-novo mutation, microcephaly and dysmorphic findings accompany resistant seizures and are associated with poor prognosis.

DISCUSSION

For patients with movement disorders, developmental delay, autism, and ID with or without epilepsy in any period of their life, next-generation sequencing is the only diagnostic technique available, with genetic analysis often being the only diagnostic method.

Genetic basis of sleep phenotypes and rare neurodevelopmental syndromes reveal shared molecular pathways

Sleep-related phenotypes have been frequently reported in early on-set epileptic encephalopathies and in developmental delay syndromes, in particular in syndromes related to autism spectrum disorder. Yet the convergent pathogenetic mechanisms between these comorbidities are largely unknown. We first performed a gene enrichment study that identified shared risk genes among rare epileptic encephalopathies/neurodevelopmental disorders, rare developmental delay genetic syndromes and sleep disturbances. We then determined cellular and molecular pathways enriched among genes shared between sleep phenotypes and those two early onset mental illnesses, aiming to identify genetic disparities and commonalities among these phenotypic groups. The sleep gene set was observed as significantly overlapped with the two gene lists associated to rare genetic syndromes (i.e., epileptic encephalopathies/neurodevelopmental disorders and developmental delay gene sets), suggesting shared genetic contribution. Similarities across significantly enriched pathways between the two intersect lists comprehended mostly synapse-related pathways, such as retrograde endocannabinoid signaling, serotonergic, and GABAergic synapse. Network analysis indicates epileptic encephalopathies/neurodevelopmental disorders versus sleep-specific clusters and developmental delay versus sleep-specific clusters related to synaptic and transcriptional regulation, respectively. Longstanding functional patterns previously described in epileptic encephalopathies and neurodevelopmental disorders genetic architecture were recaptured after dissecting the overlap between the genes associated to those developmental phenotypes and sleep disturbances, suggesting that during neurodevelopment different molecular and functional mechanisms are related to alterations on circadian rhythm. The overlapping gene set and biological pathways highlighted by this study may serve as a primer for new functional investigations of shared molecular mechanisms between sleep disturbances and rare developmental syndromes.

Case report: Dravet syndrome, feeding difficulties and gastrostomy

Dravet syndrome (DS) is a developmental and epileptic encephalopathy associated with variants in the voltage-gated sodium channel alpha 1 subunit (SCN1A) gene in around 90% of individuals. The core phenotype is well-recognized, and is characterized by seizure onset in infancy, typically with prolonged febrile seizures, followed by the emergence of multiple seizure types that are frequently drug-resistant, developmental delay, and intellectual disability. Comorbidities are common and include autism spectrum disorder, gait impairment, scoliosis, and sleep disorder. Feeding difficulties and weight loss are frequently reported by DS caregivers, and negatively impact quality of life, yet have received little attention. Here we report an adult with DS who developed reduced food and fluid intake in adolescence, resulting in weight loss and malnutrition. No underlying cause for her feeding difficulties was identified, and she subsequently required insertion of a percutaneous endoscopic gastrostomy. We review the occurrence of feeding difficulties in people with DS and discuss potential mechanisms.

The clinical, economic, and humanistic burden of Dravet syndrome - A systematic literature review

Dravet syndrome (DS) is a developmental and epileptic encephalopathy with evolving disease course as individuals age. In recent years, the treatment landscape of DS has changed considerably, and a comprehensive systematic review of the contemporary literature is lacking. Here we synthesized published evidence on the occurrence of clinical impacts by age, the economic and humanistic (health-related quality-of-life [HRQoL]) burden, and health state utility. We provide an evidence-based, contemporary visualization of the clinical manifestations, highlighting that DS is not limited to seizures; non-seizure manifestations appear early in life and increase over time, contributing significantly to the economic and humanistic burden of disease. The primary drivers of HRQoL in DS include seizure severity, cognition, and motor and behavioral problems; in turn, these directly affect caregivers through the extent of assistance required and consequent impact on activities of daily living. Unsurprisingly, costs are driven by seizure-related events, hospitalizations, and in-home medical care visits. This systematic review highlights a paucity of longitudinal data; most studies meeting inclusion criteria were cross-sectional or had short follow-up. Nonetheless, available data illustrate the substantial impact on individuals, their families, and healthcare systems and establish the need for novel therapies to address the complex spectrum of DS manifestations.

A systematic review of adults with Dravet syndrome

Dravet Syndrome (DS) is a rare and severe infantile-onset epileptic encephalopathy. DS research focuses mainly on children. We did a systematic review, completed on January 18^th, 2021, examining the number of clinical DS studies. We show that there are 208 studies on children exclusively, 28 studies on adults exclusively, and 116 studies involving adults and children combined. This 7:1 ratio of children to adult studies exclusively shows the dearth of research that addresses long-term natural history of DS into adulthood. Through this systematic review, we examine the most up-to-date information in DS adults as it pertains to seizures, electroencephalogram, imaging, treatment, motor abnormalities, cognitive and social behavior outcomes, cardiac abnormalities, sleep disturbances, diagnosis in adults, and mortality. Overall, the frequency of seizures increases in the first decade of life and then myoclonic, atypical absences and focal seizures with impaired awareness tend to decrease in frequency or even disappear in adulthood. Adults tend to have a notable reduction in status epilepticus, especially after 30 years of age. Parkinsonian features were seen in patients as young as 19 years old and are more severe in older patients, suggesting a progression of the parkinsonian symptoms. In adulthood, patients continue to present with behavior problems, associated with a lower health-related quality of life. The leading reported cause of death in DS adults is Sudden Unexpected Death in Epilepsy (SUDEP). Further studies in older adults are needed to understand the long-term outcomes of patients with DS.

Epilepsy-Related Voltage-Gated Sodium Channelopathies: A Review

Epilepsy is a disease characterized by abnormal brain activity and a predisposition to generate epileptic seizures, leading to neurobiological, cognitive, psychological, social, and economic impacts for the patient. There are several known causes for epilepsy; one of them is the malfunction of ion channels, resulting from mutations. Voltage-gated sodium channels (NaV) play an essential role in the generation and propagation of action potential, and malfunction caused by mutations can induce irregular neuronal activity. That said, several genetic variations in NaV channels have been described and associated with epilepsy. These mutations can affect channel kinetics, modifying channel activation, inactivation, recovery from inactivation, and/or the current window. Among the NaV subtypes related to epilepsy, NaV1.1 is doubtless the most relevant, with more than 1500 mutations described. Truncation and missense mutations are the most observed alterations. In addition, several studies have already related mutated NaV channels with the electrophysiological functioning of the channel, aiming to correlate with the epilepsy phenotype. The present review provides an overview of studies on epilepsy-associated mutated human NaV1.1, NaV1.2, NaV1.3, NaV1.6, and NaV1.7.

More daytime sleepiness and worse quality of sleep in patients with Dravet Syndrome compared to other epilepsy patients

AIM

Sleep problems are often reported in patients with a Dravet Syndrome (DS). In this study we explored the sleep behavior in DS and compared the prevalence of sleep problems with other epilepsy patients.

METHODS

An online questionnaire based on the 'Sleep Behavior Questionnaire by Simonds & Parraga (SQ-SP)' was distributed amongst DS parents and a control group (parents from children with epilepsy). Completed questionnaires were evaluated by factor scores and Composite Sleep Index (CSI).

RESULTS

Fifty-six responses were recorded in the DS group (42 were ≤18 year). Caregivers reported an overall frequency of sleep problems in 42.3% (22/52). Severe sleep problems, measured by CSI, were found in 28.3% (13/46) mainly related to night waking or daytime sleepiness. In the control group (n = 66, 62 were ≤18 year), sleep problems were reported by 21.2% (14/52) of the parents. Comparison analysis between pediatric DS and epilepsy patients revealed no significant differences between the prevalence of different types of sleep disorders, except for daytime sleepiness (p = 0.042). However, the parent (or caregiver)-reported quality of sleep was significantly lower in the DS group (p = 0.011).

INTERPRETATION

Sleep problems are frequent in DS patients and are mainly related to daytime sleepiness and night waking. Compared with other epilepsy patients, severe sleep problems are not more common in patients with a DS. However DS patients tend to have more mild night waking problems, which may explain the worse parental-reported sleep quality in DS patients.

Cyclic alternating pattern in infants with congenital hypothyroidism

Congenital hypothyroidism is defined as thyroid hormone deficiency present at birth which is crucial for brain development. Recently, the cyclic alternating pattern, a rhythm present in electroencephalography recordings in non-Rapid eye movement sleep, has been related to brain development and cognition in different pediatric conditions. Therefore, we evaluated the cyclic alternating pattern rate in infants with congenital hypothyroidism, thyroxine supplementation, and healthy controls. The parameters of the cyclic alternating pattern were evaluated in 19 healthy infants (10 female, mean age 25.5 ± 15.5 months) and 21 infants diagnosed with congenital hypothyroidism (19 female, mean age 24.3 ± 19.0 months). We considered the transient electro-cortical activations (phase A of the cycle) in non-Rapid eye movement sleep and the subdivisions of the A phase in: A1, A2 and A3, based on their frequency content. All subjects were subjected to polysomnography recording in a standard laboratory setting. Sleep data were stored computer following the International 10-20 System. Data showed that congenital hypothyroidism infants exhibited higher frequency of central apnea, hypopnea, and arousals in comparison to controls. Particularly, central apnea index decreased with age in the control group but not in congenital hypothyroidism group. Regarding to cyclic alternating pattern measurements, congenital hypothyroidism infants exhibit a higher frequency in the percentage of A3 subtype (electroencephalographic desynchrony) and conversely a lower percentage of A1 subtype (electroencephalographic synchrony), than healthy infants. An important finding of this study is the positive correlation between A1 mean duration and age, which is bigger in control group than in congenital hypothyroidism group (time duration in control group (0.52 s/month) versus congenital hypothyroidism group (0.1 s/month). Infants with congenital hypothyroidism showed an increase of A3 subtype, of central apnea, and of arousals. The reduction of percentage and mean duration of A1 subtype could be a valuable indicator of sleep development in patients with congenital hypothyroidism and healthy infants.

Randomized Controlled Trial of Melatonin for Sleep Disturbance in Dravet Syndrome: The DREAMS Study

STUDY OBJECTIVES

Dravet syndrome is a severe developmental and epileptic encephalopathy, in which 75% of patients have sleep disturbance. Melatonin is often used for sleep problems in childhood; however, there is no quality evidence supporting its use in Dravet syndrome. We hypothesized that melatonin would increase total sleep and quality of life for patients with Dravet syndrome.

METHODS

A double-blind crossover randomized placebo-controlled trial was conducted, comparing 6 mg regular-release melatonin to placebo for patients with Dravet syndrome and sleep disturbance. The primary outcome measure was total sleep measured by actigraphy, with secondary outcomes including wakefulness after sleep onset (WASO), Sleep Disturbance Scale in Children and Quality of Life in Children with Epilepsy 55 questionnaires, caregiver reports of clinical change, seizure diary and serum antiepileptic drug levels. We also compared actigraphy data of patients with Dravet syndrome to an age-matched healthy control group.

RESULTS

A total of 13 patients completed the study. There was no difference in total sleep or WASO between melatonin and placebo. However, of the 11 patients for whom caregivers reported a clear clinical difference between treatments (blinded), 8 reported improvement on melatonin (P < .05). Interestingly, when compared to patients in the control group, patients with Dravet syndrome had significantly increased total sleep (P = .002).

CONCLUSIONS

Melatonin did not increase total sleep; however, blinded caregiver reports indicate treatment with melatonin provided considerable clinical benefit for some patients with Dravet syndrome and sleep disturbance.

CLINICAL TRIAL REGISTRATION

Registry: Australian Government Department of Health, Therapeutic Goods Administration under the Clinical Trials Notification Scheme (protocol number 2241).

Overnight Video-Polysomnographic Studies in Children with Intractable Epileptic Encephalopathies

Background

The aim of this study was to assess sleep architecture and respiration during sleep in children with intractable epileptic encephalopathies using overnight video-polysomnography (V-PSG).

Material/Methods

Between 2015 to 2017 overnight V-PSG recordings were made for 31 children (22 boys and 9 girls) with intractable epileptic encephalopathy with a mean age of 6.78±3.61 years and a mean body mass index (BMI) of 15.83±3.16 kg/m³. Thirty-one healthy children were matched for sex, age, and BMI as the control group. The phases of sleep studied included rapid eye movement (REM) sleep, and non-REM (NREM) phases NREM 1, NREM 2, and NREM 3. Respiratory function during sleep was evaluated.

Results

Children with epileptic encephalopathies receiving antiepileptic treatment had significantly decreased total sleep time (TST) (p=0.038), significantly increased percentage of NREM1 (p=0.033), and a significantly lower percentage of total REM (p<0.0001), compared with the control group. All children 31/31 (100%) with epileptic encephalopathies had interictal epileptiform discharges, and 4/31 (12.9%) had ictal events. The number of respiratory events did not differ significantly between the two groups (p=0.118), but children in the epileptic encephalopathy group had a significantly shorter average duration (p=0.008) and longest duration (p=0.048) of respiratory events. Average (p=0.006) and least (p=0.0004) oxygen saturation (SatO₂) were significantly lower in children with epileptic encephalopathies compared with the control group.

Conclusions

Children with epileptic encephalopathies had altered sleep architecture and marked oxygen desaturation, which supports the need for referral of children with epileptic encephalopathy for overnight sleep evaluation.

Preclinical Animal Models for Dravet Syndrome: Seizure Phenotypes, Comorbidities and Drug Screening

Epilepsy is a common chronic neurological disease affecting almost 3 million people in the United States and 50 million people worldwide. Despite availability of more than two dozen FDA-approved anti-epileptic drugs (AEDs), one-third of patients fail to receive adequate seizure control. Specifically, pediatric genetic epilepsies are often the most severe, debilitating and pharmaco-resistant forms of epilepsy. Epileptic syndromes share a common symptom of unprovoked seizures. While some epilepsies/forms of epilepsy are the result of acquired insults such as head trauma, febrile seizure, or viral infection, others have a genetic basis. The discovery of epilepsy associated genes suggests varied underlying pathologies and opens the door for development of new "personalized" treatment options for each genetic epilepsy. Among these, Dravet syndrome (DS) has received substantial attention for both the pre-clinical and early clinical development of novel therapeutics. Despite these advances, there is no FDA-approved treatment for DS. Over 80% of patients diagnosed with DS carry a de novo mutation within the voltage-gated sodium channel gene SCN1A and these patients suffer with drug resistant and life-threatening seizures. Here we will review the preclinical animal models for DS featuring inactivation of SCN1A (including zebrafish and mice) with an emphasis on seizure phenotypes and behavioral comorbidities. Because many drugs fail somewhere between initial preclinical discovery and clinical trials, it is equally important that we understand how these models respond to known AEDs. As such, we will also review the available literature and recent drug screening efforts using these models with a focus on assay protocols and predictive pharmacological profiles. Validation of these preclinical models is a critical step in our efforts to efficiently discover new therapies for these patients. The behavioral and electrophysiological drug screening assays in zebrafish will be discussed in detail including specific examples from our laboratory using a zebrafish scn1 mutant and a summary of the nearly 3000 drugs screened to date. As the discovery and development phase rapidly moves from the lab-to-the-clinic for DS, it is hoped that this preclinical strategy offers a platform for how to approach any genetic epilepsy.

Sleep problems in Dravet syndrome: a modifiable comorbidity

AIM

Many children with severe developmental and epileptic encephalopathies experience significant sleep disturbance, causing major disruption to the family's quality of life. We aimed to determine the frequency and nature of sleep problems in individuals with Dravet syndrome.

METHODS

The Sleep Disturbance Scale for Children and a seizure questionnaire were distributed to the parents/guardians of 96 patients with Dravet syndrome. Sixteen patients had two nights of home oximetry.

RESULTS

Fifty-seven out of 96 questionnaires were completed. Forty-three out of 57 (75%) individuals had sleep problems. Twenty-five out of 57 (44%) individuals had an abnormal total sleep score, with difficulty initiating and maintaining sleep (22 out of 57, 39%), sleep-wake transition disorders (20 out of 57, 35%), and sleep breathing disorders (19 out of 57, 33%). Twenty-two out of 57 (39%) individuals took medication to assist sleep, predominantly melatonin (n=14). Thirty out of 57 (53%) recently had nocturnal seizures. Overnight oximetry showed 14 out of 16 (88%) had a higher oxygen desaturation index (>3%), and six out of 16 (38%) had higher mean pulse rates than normative values. Home oximetry was normal or inconclusive in all patients.

INTERPRETATION

Seventy-five per cent of individuals with Dravet syndrome had sleep problems, highlighting the importance of routinely assessing sleep and initiating appropriate behavioural and pharmacological interventions to improve the patient and family's quality of life. A high oxygen desaturation index and mean pulse rates on pulse oximetry may reflect unrecognized nocturnal seizures.

WHAT THIS PAPER ADDS

More than 70% of patients with Dravet syndrome have sleep problems. Difficulty initiating and maintaining sleep was most common, particularly in those older than 20 years. Second most common were sleep-wake transition disorders, affecting more than 50% of those younger than 5 years. Sleep breathing disorders were a frequent problem across all age groups. Oximetry was not diagnostic of sleep-disordered breathing or obvious seizures.

Parental Perception of Comorbidities in Children With Dravet Syndrome

BACKGROUND

We hypothesized that children with Dravet syndrome may have additional common features beyond seizures and cognitive impairment. To address this gap in knowledge, we conducted a survey of caregivers of children with Dravet syndrome to identify and quantify their perception of associated symptoms in this population.

METHODS

An electronic survey was developed in REDcap (Research Electronic Data Capture) and sent via e-mail to the participants on the Dravet Syndrome Foundation e-mail list. Questions focused on eating, sleep, behavior, and other symptoms that might be related to Dravet syndrome. The questions were assessed using a four-point Likert scale (e.g., strongly agree to strongly disagree). Results were later dichotomized for analysis. Logistic regression was used to calculate odds ratios of various demographic factors potentially associated with symptoms. Multivariable models were constructed using backward elimination to assess the relationship among a variety of symptoms.

RESULTS

There were 202 respondents, 96% were parents of a child with Dravet syndrome (the remainder were grandparents or guardians); 90.5% were female. The median age of the affected child was eight years (interquartile range five to 14), 50% were male, and 90.5% were reported to have a known SCN1A mutation. At least one symptom associated with appetite was reported in 99% of respondents, 82% reported a disturbance of sleep, one third reported autonomic symptoms, and 75% reported problems with gait. Inattention and perseveration were reported more commonly than other behavioral disturbances.

SIGNIFICANCE

Caregivers have the perception of many symptoms in children with Dravet syndrome in addition to those that have been previously reported, including appetite, sleep, gait, and behavior. Many of these can significantly affect quality of life for both the child and the caregiver.

Cardiovascular safety of low-dose fenfluramine in Dravet syndrome: a review of its benefit-risk profile in a new patient population

OBJECTIVE

Dravet syndrome (DS) is a rare, treatment-resistant epilepsy syndrome for which current treatment regimens are often ineffective. Fenfluramine is currently in development for treatment of DS, based on reports in the 1980s and 1990s of its anti-epileptic activity in pediatric patients with intractable epilepsy. However, fenfluramine was withdrawn from global markets in 1997 following reports of its association with pulmonary hypertension and heart valve disease in adult patients treated for obesity. This review was conducted to assess cardiac safety of fenfluramine when used at lower doses for treatment of DS.

METHODS

Pubmed was searched for clinical studies of fenfluramine in obese adults who reported incidence of heart valve disease. These data were reviewed against published results from Belgian patients with DS who have been treated with low-dose fenfluramine for up to 28 years.

RESULTS

Nine controlled studies of fenfluramine and related compounds (dexfenfluramine and/or phentermine) which assessed incidence and severity of cardiac valve disease in 3,268 treated patients and 2,017 control subjects have been reported. Mild or greater aortic valve regurgitation was found in 9.6% of treated patients compared with 3.9% of control subjects, and moderate or greater mitral valve regurgitation was found in 3.1% of treated patients and 2.5% of control subjects. Nineteen DS patients have been treated for up to 28 years with 10-20 mg/day fenfluramine, with no clinical signs or symptoms of cardiac valve disease or pulmonary hypertension. Slight and clinically unimportant changes in valve structure have been seen on echocardiography in five patients at some time during the observation period.

CONCLUSIONS

A different benefit-risk relationship appears to be emerging when fenfluramine is used at low doses for extended periods in young patients with DS. Continued cardiac assessments during ongoing Phase 3 clinical trials will provide additional safety information for this potential new and effective treatment.

Behavioral Comorbidities and Drug Treatments in a Zebrafish scn1lab Model of Dravet Syndrome

Loss-of-function mutations in SCN1A cause Dravet syndrome (DS), a catastrophic childhood epilepsy in which patients experience comorbid behavioral conditions, including movement disorders, sleep abnormalities, anxiety, and intellectual disability. To study the functional consequences of voltage-gated sodium channel mutations, we use zebrafish with a loss-of-function mutation in scn1lab, a zebrafish homolog of human SCN1A. Homozygous scn1lab^s552/s552 mutants exhibit early-life seizures, metabolic deficits, and early death. Here, we developed in vivo assays using scn1lab^s552 mutants between 3 and 6 d postfertilization (dpf). To evaluate sleep disturbances, we monitored larvae for 24 h with locomotion tracking software. Locomotor activity during dark (night phase) was significantly higher in mutants than in controls. Among anticonvulsant drugs, clemizole and diazepam, but not trazodone or valproic acid, decreased distance moved at night for scn1lab^s552 mutant larvae. To monitor exploratory behavior in an open field, we tracked larvae in a novel arena. Mutant larvae exhibited impaired exploratory behavior, with increased time spent near the edge of the arena and decreased mobility, suggesting greater anxiety. Both clemizole and diazepam, but not trazodone or valproic acid, decreased distance moved and increased time spent in the center of the arena. Counting inhibitory neurons in vivo revealed no differences between scn1lab^s552 mutants and siblings. Taken together, our results demonstrate conserved features of sleep, anxiety, and movement disorders in scn1lab mutant zebrafish, and provide evidence that a zebrafish model allows effective tests of treatments for behavioral comorbidities associated with DS.

Not all SCN1A epileptic encephalopathies are Dravet syndrome: Early profound Thr226Met phenotype

Objective:

To define a distinct SCN1A developmental and epileptic encephalopathy with early onset, profound impairment, and movement disorder.

Methods:

A case series of 9 children were identified with a profound developmental and epileptic encephalopathy and SCN1A mutation.

Results:

We identified 9 children 3 to 12 years of age; 7 were male. Seizure onset was at 6 to 12 weeks with hemiclonic seizures, bilateral tonic-clonic seizures, or spasms. All children had profound developmental impairment and were nonverbal and nonambulatory, and 7 of 9 required a gastrostomy. A hyperkinetic movement disorder occurred in all and was characterized by dystonia and choreoathetosis with prominent oral dyskinesia and onset from 2 to 20 months of age. Eight had a recurrent missense SCN1A mutation, p.Thr226Met. The remaining child had the missense mutation p.Pro1345Ser. The mutation arose de novo in 8 of 9; for the remaining case, the mother was negative and the father was unavailable.

Conclusions:

Here, we present a phenotype-genotype correlation for SCN1A. We describe a distinct SCN1A phenotype, early infantile SCN1A encephalopathy, which is readily distinguishable from the well-recognized entities of Dravet syndrome and genetic epilepsy with febrile seizures plus. This disorder has an earlier age at onset, profound developmental impairment, and a distinctive hyperkinetic movement disorder, setting it apart from Dravet syndrome. Remarkably, 8 of 9 children had the recurrent missense mutation p.Thr226Met.

Optimizing the Diagnosis and Management of Dravet Syndrome: Recommendations From a North American Consensus Panel

OBJECTIVES

To establish standards for early, cost-effective, and accurate diagnosis; optimal therapies for seizures; and recommendations for evaluation and management of comorbidities for children and adults with Dravet syndrome, using a modified Delphi process.

METHODS

An expert panel was convened comprising epileptologists with nationally recognized expertise in Dravet syndrome and parents of children with Dravet syndrome, whose experience and understanding was enhanced by their active roles in Dravet syndrome associations. Panelists were asked to base their responses to questions both on their clinical expertise and results of a literature review that was forwarded to each panelist. Three rounds of online questionnaires were conducted to identify areas of consensus and strength of that consensus, as well as areas of contention.

RESULTS

The panel consisted of 13 physicians and five family members. Strong consensus was reached regarding typical clinical presentation of Dravet syndrome, range of electroencephalography and magnetic resonance imaging findings, need for genetic testing, critical information that should be conveyed to families at diagnosis, priorities for seizure control and typical degree of control, seizure triggers and recommendations for avoidance, first- and second-line therapies for seizures, requirement and indications for rescue therapy, specific recommendations for comorbidity screening, and need for family support. Consensus was not as strong regarding later therapies, including vagus nerve stimulation and callosotomy, and for specific therapies of associated comorbidities. Beyond the initial treatment with benzodiazepines and use of valproate, there was no consensus on the optimal in-hospital management of convulsive status epilepticus.

CONCLUSIONS

We were able to identify areas where there was strong consensus that we hope will (1) inform health care providers on optimal diagnosis and management of patients with Dravet syndrome, (2) support reimbursement from insurance companies for genetic testing and Dravet syndrome-specific therapies, and (3) improve quality of life for patients with Dravet syndrome and their families by avoidance of unnecessary testing and provision of an early accurate diagnosis allowing optimal selection of therapeutic strategies.

Treatment of Dravet Syndrome

Dravet syndrome is among the most challenging electroclinical syndromes. There is a high likelihood of recurrent status epilepticus; seizures are medically refractory; and patients have multiple co-morbidities, including intellectual disability, behaviour and sleep problems, and crouch gait. Additionally, they are at significant risk of sudden unexplained death. This review will focus predominantly on the prophylactic medical management of seizures, addressing both first-line therapies (valproate and clobazam) as well as second-line (stiripentol, topiramate, ketogenic diet) or later options (levetiracetam, bromides, vagus nerve stimulation). Sodium channel agents-including carbamazepine, oxcarbazepine, phenytoin and lamotrigine-should be avoided, as they typically exacerbate seizures. Several agents in development may show promise, specifically fenfluramine and cannabidiol, but they need further evaluation in randomized, controlled trials. In addition to prophylactic treatment, all patients need home-rescue medication and a status epilepticus protocol that can be carried out in their local hospital. Families must be counselled on non-pharmacologic strategies to reduce seizure risk, including avoidance of triggers that commonly induce seizures (including hyperthermia, flashing lights and patterns). In addition to addressing seizures, holistic care for a patient with Dravet syndrome must involve a multidisciplinary team that includes specialists in physical, occupational and speech therapy, neuropsychology, social work and physical medicine.

Dravet Syndrome: Diagnosis and Long-Term Course

Dravet syndrome is one of the most severe epilepsy syndromes of early childhood, and it comes with very high morbidity and mortality. The typical presentation is characterized by hemiclonic or generalized clonic seizures triggered by fever during the first year of life, followed by myoclonic, absence, focal and generalized tonic-clonic seizures. Non-convulsive status epilepticus and epileptic encephalopathy are common. Development is normal in the first year of life, but most individuals eventually suffer from intellectual impairment. Dravet syndrome is associated with mutations in the sodium channel alpha1 subunit gene (SCN1A) in 70-80% of individuals. SCN1A mutation results in inhibition of the GABAergic inhibitory interneurons, leading to excessive neuronal excitation. The "interneuron hypothesis" is the current most accepted pathophysiological mechanism of Dravet syndrome. The mortality rate is increased significantly in Dravet syndrome. Ataxia, a characteristic crouched gait and Parkinson's symptoms may develop in some individuals. It is likely that Dravet syndrome is underdiagnosed in adults with treatment-resistant epilepsy. Early diagnosis is important to avoid anti-seizure medications that exacerbate seizures.