Dysarthria and broader motor speech deficits in Dravet syndrome

Autism and attention-deficit/hyperactivity disorder in children with Dravet syndrome: A population-based study

AIM

To identify on a population basis the prevalence of autism and attention-deficit/hyperactivity disorder (ADHD) in children with Dravet syndrome and factors associated with symptoms of autism and ADHD.

METHOD

Forty-one of 48 children with Dravet syndrome living in Sweden, born between 1st January 2000 and 31st December 2018 underwent assessment including measures of autism and ADHD. Diagnoses of autism and ADHD were made with respect to DSM-5 criteria. Factors associated with features of autism and ADHD were analysed via regression.

RESULTS

Twenty-five of the 41 children fulfilled DSM-5 criteria for autism spectrum disorder and 12 of 37 children considered for an ADHD diagnosis fulfilled DSM-5 criteria for ADHD. Severe intellectual disability was significantly associated with a greater degree of autistic features (p < 0.001) and a DSM-5 diagnosis of autism spectrum disorder (p = 0.029). Younger children had significantly more features of ADHD (p = 0.004) and features of inattention were significantly more common than features of hyperactivity/impulsivity (p < 0.001).

INTERPRETATION

Children with Dravet syndrome often have significant features of autism and ADHD, primarily inattentive type. Screening for autism and ADHD should be routine in children with Dravet syndrome.

WHAT THIS PAPER ADDS

In total, 25 of 41 assessed children with Dravet syndrome fulfilled DSM-5 criteria for autism. Twelve of 37 assessed children with Dravet Syndrome met DSM-5 criteria for attention-deficit/hyperactivity disorder (ADHD). Severe intellectual disability was significantly associated with a greater degree of autism spectrum disorder features. Younger children had significantly more features of ADHD.

Health-related quality of life, depression, anxiety, and sleep in mothers and fathers of children with dravet syndrome in Sweden

PURPOSE

To evaluate health-relatedquality of life(HRQoL), depression, anxiety and sleep in caregivers (mothers and fathers) of children with Dravet Syndrome (DS).

METHODS

Mothers (n = 41) and fathers (n = 39) of 42 children with DS completed the Rand 36-Item Short Form Health Survey (SF-36), the Hospital Anxiety and Depression Scale(HADS), and the Insomnia Severity Index (ISI). Mothers' and fathers' SF-36 scores were compared with Swedish population values for males and females using t-tests. Differences in proportions of mothers vs. fathers classified as 'noncases' or 'possible/probable' cases of anxiety (HADS-A) and depression (HADS-D), respectively, were assessed with the chi-square test. Parents' SF-36, HADS symptom and ISI scores were compared using t-tests. Linear regression analysis was employed to explore factors associated with sleep and mental health.

RESULTS

Mothers had significantly lower scores compared with population norms on seven of eight SF-36 domains whilst fathers had lower scores on five domains. Mothers had significantly lower scores than fathers on one (i.e. Role limitation - emotional) SF-36 domain. A larger proportion of mothers than fathers had 'possible/probable' anxiety (83 % vs 59 %; p = 0.018), but not depression (46 % vs. 46 %; p = 0.987). Mothers reported more symptoms of anxiety than fathers (p = 0.007) but there was no difference in depression (p = 0.399). Mothers (78 %) reported more sleep difficulties than fathers (67 %) but the difference was not significant (p = 0.254). Sleep difficulties were predicted by mental health difficulties and vice versa, in mothers and fathers (all p < 0.001). Increased child sleep difficulties were associated with increased maternal sleep difficulties (p = 0.003) but not paternal sleep difficulties.

CONCLUSION

Parents of children with DS have high levels of mental health and sleep difficulties and reduced HRQoL. Mothers experienced higher levels of anxiety, but not depression, than fathers. There is a need to screen parents of children for these difficulties and develop interventions to ameliorate the difficulties.

How Encephalopathy Impacts Language Ability: A Scoping Review of the Linguistic Abilities of Adults with Developmental and Epileptic Encephalopathy

Background and Objectives: Developmental and epileptic encephalopathy refers to a group of conditions where patients experience abnormal development due to various causes as well as frequent epileptiform discharges that ultimately contribute, in an independent and additive fashion, to cognitive and linguistic impairments. The language and cognition outcome of these patients in adulthood has been understudied. This paper aims to present a scoping review of linguistic abilities in adults with developmental and epileptic encephalopathy to determine the extent to which language outcomes in adulthood and their relation to cognitive outcomes have been studied. Design: Two online databases were searched and the methodological framework by Arksey & O'Malley (2005) was adopted. Results: Out of the 27 selected studies, only 13 exclusively examined adults, 15 were group studies, 5 were case studies and 7 were case series. A total of 9 out of the 15 group studies provided individual results for adults. Twenty-two studies included a follow-up examination. Twenty-three studies addressed the relationship between language and cognition. The selected studies indicate the presence of language impairments, which are nevertheless differentially manifested in the syndromes under investigation, whereas individual variability is also reported. Aspects of cognition seem to correlate with linguistic abilities. Conclusions: In sum, despite variability in linguistic abilities, language deficits constitute a significant aspect of the clinical profile of many adults with developmental and epileptic encephalopathy, a finding that should be taken into account for the treatment protocols of these individuals.

Developmental and epileptic encephalopathies

Developmental and epileptic encephalopathies, the most severe group of epilepsies, are characterized by seizures and frequent epileptiform activity associated with developmental slowing or regression. Onset typically occurs in infancy or childhood and includes many well-defined epilepsy syndromes. Patients have wide-ranging comorbidities including intellectual disability, psychiatric features, such as autism spectrum disorder and behavioural problems, movement and musculoskeletal disorders, gastrointestinal and sleep problems, together with an increased mortality rate. Problems change with age and patients require substantial support throughout life, placing a high psychosocial burden on parents, carers and the community. In many patients, the aetiology can be identified, and a genetic cause is found in >50% of patients using next-generation sequencing technologies. More than 900 genes have been identified as monogenic causes of developmental and epileptic encephalopathies and many cell components and processes have been implicated in their pathophysiology, including ion channels and transporters, synaptic proteins, cell signalling and metabolism and epigenetic regulation. Polygenic risk score analyses have shown that common variants also contribute to phenotypic variability. Holistic management, which encompasses antiseizure therapies and care for multimorbidities, is determined both by epilepsy syndrome and aetiology. Identification of the underlying aetiology enables the development of precision medicines to improve the long-term outcome of patients with these devastating diseases.

Survey of rehabilitation approaches and plans for individuals with dravet syndrome (RAPIDS) in Italy: Current practices and strategies to progress

Dravet syndrome, a developmental and epileptic encephalopathy, manifests with varying degrees of cognitive and communication impairment, postural and movement disorders (such as ataxia, coordination issues, and crouch gait) and behavioural challenges (including attention deficit/hyperactivity, oppositional/defiant behaviour, and autistic traits). Rehabilitation is a valuable tool for most patients, typically prescribed to address the most pressing issues. However, current practices often fall short in proactively preventing and treating known challenges associated with the syndrome, as indicated by the latest literature, at different life stages. Furthermore, there is a notable lack of evidence regarding treatment types and efficacy specific to people with Dravet Syndrome. Conducted in collaboration with one of the Italian Patient associations, this national survey provides a comprehensive view of the rehabilitation landscape in Dravet Syndrome, as perceived by caregivers. It outlines the types of treatments for 51 patients, based on age and relevant clinical features. The findings reveal a heterogenous rehabilitation approach, only partly tailored to the presence of specific comorbidities, and underline numerous unmet needs. Compared to the past there is indirect evidence that more patients are offered early rehabilitation. Nonetheless, while nowadays speech therapy and neuropsychomotor therapy are nearly universal for children up to the age of 10, some begin physiotherapy and psychotherapy thereafter, with a majority discontinuing treatments. Therefore, families of adolescent and adult patients often face a lack of comprehensive support, predominantly offered when epilepsy is more challenging to control affecting rehabilitation adherence and effectiveness. Finally, a negligible minority is offered treatments such as neurovisual training, augmentative and alternative communication, and occupational therapy. Many of these considerations could apply to other developmental and epileptic encephalopathy with lifelong disability. This survey calls for more data collection on this important topic for more efficient allocation of rehabilitation resources.

Diagnosis, epilepsy treatment and supports for neurodevelopment in children with Dravet Syndrome: Caregiver reported experiences and needs

BACKGROUND

Dravet syndrome is a rare infantile onset epilepsy syndrome encompassing treatment resistant epilepsy and neurodevelopmental difficulties. There is limited data regarding caregiver experiences of diagnosis, treatment and supports for the associated neurodevelopmental problems.

METHOD

Semi-structured interviews were conducted with caregivers of 36/48 children (75% of total population in Sweden) with Dravet syndrome. Data was analysed using thematic analysis.

RESULTS

Regarding the diagnostic experience, themes were: Delays in diagnostic process, genetic testing not optimal, communication of Dravet syndrome diagnosis and support and information soon after diagnosis. Caregivers felt that delays in diagnosis and testing could have been avoided whilst experiences of communication of diagnosis and support after diagnosis varied. In terms of treatment for seizures, the themes were: Satisfied with treatment, emergency treatment, treatment with antiseizure medications, strategies to control seizures via temperature regulation/avoidance of infections and use of equipment and aids. Caregivers were in the main accepting that seizures in Dravet syndrome are very difficult to treat and that seizure freedom is often an unachievable goal. Many felt frustrated that they were expected to take responsibility with respect to choice of medication. They often employed strategies (e.g., avoidance of physical activity) to reduce seizures or their impact. In terms of supports for neurodevelopmental problems, the themes were: Struggled to access support, lack of integrated healthcare and satisfaction with school. Many caregivers felt that accessing necessary supports for their children and developmental and behavioural needs was a struggle and that the provision of support often lacked integration e.g., lack of collaboration between child's disability service and school. Caregivers also expressed a desire that there would be better knowledge of Dravet syndrome in emergency departments and schools, that care would be better integrated and that there would be more supports for assessment and interventions regarding the associated neurodevelopmental problems.

CONCLUSION

The responses of caregivers of children with Dravet syndrome highlight the need for supports from diagnosis for both epilepsy and neurodevelopmental problems. Good examples of provision were identified but parents often felt they lacked support and support often came from providers who lacked knowledge of the syndrome. Collaboration between medical, disability and school services was often lacking.

Epilepsies

Recent advances in genetic diagnosis have revealed the underlying etiology of many epilepsies and have identified pathogenic, causative variants in numerous ion and ligand-gated channel genes. This chapter describes the clinical presentations of epilepsy associated with different channelopathies including classic electroclinical syndromes and emerging gene-specific phenotypes. Also discussed are the archetypal epilepsy channelopathy, SCN1A-Dravet syndrome, considering the expanding phenotype. Clinical presentations where a channelopathy is suspected, such as sleep-related hypermotor epilepsy and epilepsy in association with movement disorders, are reviewed. Channelopathies pose an intriguing problem for the development of gene therapies. Design of targeted therapies requires physiologic insights into the often multifaceted impact of a pathogenic variant, coupled with an understanding of the phenotypic spectrum of a gene. As gene-specific novel therapies come online for the channelopathies, it is essential that clinicians are able to recognize epilepsy phenotypes likely to be due to channelopathy and institute early genetic testing in both children and adults. These findings are likely to have immediate management implications and to inform prognostic and reproductive counseling.

Gastrointestinal and eating problems in SCN1A-related seizure disorders

OBJECTIVE

Our study aimed to describe the prevalence and characteristics of gastrointestinal and eating problems in Dravet syndrome (DS) and other SCN1A-related seizure disorders and to determine the association between the occurrence of gastrointestinal and eating problems and core features of DS.

METHODS

Gastrointestinal and eating problems were assessed with a questionnaire in a Dutch cohort of participants with an SCN1A-related seizure disorder. Associations between the number of gastrointestinal and eating problems and core features of DS, seizure severity, level of intellectual disability, impaired mobility, behavioral problems, and use of anti-seizure medication, were explored by multivariate ordinal regression analyses. Symptoms were divided into the categories dysphagia-related, behavioral, and gastrointestinal, and were assessed separately.

RESULTS

One hundred sixty-nine participants with an SCN1A-related seizure disorder, of whom 118 (69.8%) with DS and 51 (30.2%) with Generalized Epilepsy with Febrile Seizures Plus / Febrile Seizures (GEFS+/FS), the non-DS phenotype, were evaluated. Gastrointestinal and eating problems were highly prevalent in DS participants, 50.8% had more than three symptoms compared to 3.9% of non-DS participants. Of participants with DS, 17.8% were fully or partly fed by a gastric tube. Within the three different symptom categories, the most prevalent dysphagia-related symptom was drooling (60.7%), distraction during mealtimes (61.4%) the most prevalent behavioral symptom, and constipation and loss of appetite (both 50.4%) the most prevalent gastrointestinal symptoms. DS participants who use a wheelchair (odds ratio (OR) 4.9 95%CI (1.9-12.8) compared to walking without aid), who use ≥3 anti-seizure medications (ASM) (OR 5.9 95%CI (1.9-18.2) compared to <3 ASM) and who have behavioral problems (OR 3.0 95%CI (1.1-8.1) compared to no behavioral problems) had more gastrointestinal and eating problems.

CONCLUSION

Gastrointestinal and eating problems are frequently reported symptoms in DS. Distinguishing between symptom categories will lead to tailored management of patients at risk, will improve early detection, and enable a timely referral to a dietitian, behavioral expert, and/or speech therapist, ultimately aiming to improve the quality of life of both patients and caregivers.

Motor Speech Phenotypes in Children With Epilepsy: Preliminary Findings

PURPOSE

This exploratory study aimed to characterize motor speech impairments in a small sample of children with epilepsy, both with and without a known seizure etiology. A secondary aim was to evaluate the validity of the Profile for Childhood Apraxia of speech and Dysarthria (ProCAD), a newly developed tool for differential diagnosis of childhood apraxia of speech and dysarthria.

METHOD

Thirteen children with seizure disorders completed a comprehensive speech and language assessment. Three expert speech-language pathologists rated the presence of auditory-perceptual features of motor speech impairment using the ProCAD. Motor speech features, diagnoses, and standardized test scores were compared between children with a known seizure etiology and children with idiopathic epilepsy.

RESULTS

Nine of the 13 children exhibited motor speech impairment; dysarthria was the most common diagnosis. Most children (11/13) exhibited language impairment. Group comparisons showed that children with a known seizure etiology had more atypical motor speech features and lower language scores than children with idiopathic seizures.

CONCLUSION

These preliminary findings suggest a high rate of motor speech impairment among children with epilepsy.

Intellectual functioning and adaptive behaviour in children with Dravet syndrome: A population-based study

AIM

To identify, on a population basis, the prevalence of intellectual disability in children with Dravet syndrome, profiles on a measure of adaptive behaviour, and factors associated with intellectual functioning and adaptive behaviour.

METHOD

Forty-two out of 48 children with Dravet syndrome living in Sweden, born between 1st January 2000 and 31st December 2018, underwent assessment of intellectual functioning and adaptive behaviour. Factors associated with level of intellectual functioning and adaptive behaviour were analysed.

RESULTS

Eight-six per cent (n = 36) of the children fulfilled DSM-5 criteria for intellectual disability (29% [n = 12] mild intellectual disability, 24% [n = 10] moderate intellectual disability, 33% [n = 14] severe intellectual disability, 0% profound intellectual disability) and 93% (n = 39) had an adaptive behaviour composite more than two standard deviations below the mean. Communication was a significant weakness compared with daily living skills (p < 0.001; mean difference 95% confidence interval [CI] -8.193 to -4.092) and socialization (p = 0.001; mean difference 95% CI 6.511 to -1.775) on the Vineland Adaptive Behavior Scales, Second Edition. The only factors significantly associated with both decreased adaptive behaviour and presence of severe intellectual disability was the presence of increased autistic symptoms and younger age.

INTERPRETATION

Children with Dravet syndrome have a very high level of intellectual disability and almost all have significant deficits in adaptive behaviour. Greater deficits in adaptive behaviour and greater severity of intellectual disability are associated with the presence of increased autistic symptoms, highlighting the need for comprehensive neurodevelopmental assessment for all affected children.

WHAT THIS PAPER ADDS

Eighty-six per cent (n = 36) of children with Dravet syndrome fulfilled criteria for intellectual disability. Ninety-three per cent (n = 39) of children with Dravet syndrome had significant deficits in adaptive behaviour. Communication was a significant weakness on a measure of adaptive behaviour. Increased autistic symptoms were associated with greater deficits in cognition/adaptive behaviour. Older age and earlier status epilepticus were associated with decreased adaptive behaviour.

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.

Motor and behavioral phenotype of Dravet syndrome in adulthood

In a comparative cross-sectional study, 26 adult individuals with clinically typical, genetically confirmed Dravet syndrome (DS) and an equal number of individuals with early onset, problematic epilepsy, and intellectual disability (ID) of comparable severity were included. The aim of the study was to find out whether patients with DS could be clearly distinguished from the comparison group with regard to neurological and behavioral symptoms. Significant differences were found in that individuals with DS clearly more frequently exhibited a symptom cluster characterized by bradykinesia, hypomimia, hypophonia, (spastic) increased muscle tone, ataxia, sthenic perseveration, and a special interest in colors. To these symptoms must be added, according to the findings of previous examinations, mastication, camptocormia/antecollis on the one hand, and the tendency to visual hallucinations on the other hand, in order to define one neuropsychiatric phenotype of DS in adulthood. To these symptoms must be added, according to the findings of previous investigations, crouch gait with camptocormia/antecollis on the one hand, and the tendency to visual hallucinations on the other hand, in order to define one outlined neuropsychiatric phenotype of DS in adulthood.

Guidance on Dravet syndrome from infant to adult care: Road map for treatment planning in Europe

Dravet syndrome (DS) is a severe, rare, and complex developmental and epileptic encephalopathy affecting 1 in 16 000 live births and characterized by a drug‐resistant epilepsy, cognitive, psychomotor, and language impairment, and behavioral disorders. Evidence suggests that optimal treatment of seizures in DS may improve outcomes, even though neurodevelopmental impairments are the likely result of both the underlying genetic variant and the epilepsy. We present an updated guideline for DS diagnosis and treatment, taking into consideration care of the adult patient and nonpharmaceutical therapeutic options for this disease. This up‐to‐date guideline, which is based on an extensive review of the literature and culminates with a new treatment algorithm for DS, is a European consensus developed through a survey involving 29 European clinical experts in DS. This guideline will serve professionals in their clinical practice and, as a consequence, will benefit DS patients and their families.

Dravet syndrome: A quick transition guide for the adult neurologist

INTRODUCTION

Dravet syndrome (DS) is still seen as a "pediatric disease", where patients receive excellent care in pediatric centers, but care is less than optimal in adult health care systems (HCS). This creates a barrier when young adults need to leave the family-centered pediatric system and enter the adult, patient-centered HCS. Here we create a guide to help with the transition from pediatric to adult for patients with DS.

METHODS

Experts in Dravet syndrome flagged the main barriers in caring for adults with DS and created a 2-page transition summary guide based on their expertise and a literature review.

RESULTS

The 2-page guide addresses: DS diagnosis in children and adults; clinical manifestations, including the differences in seizures types and frequencies between children and adults with DS; the natural history of intellectual disability, behavior, gait, motor disorders and dysautonomia; a review of optimal treatments (including medications not commonly used in adult epilepsy settings such as stiripentol and fenfluramine), as well as emergency seizure management; avoidance of triggers, preventive measures, and vaccine administration in adults with DS.

CONCLUSION

Several young adults with DS are still followed by their child neurologist. This 2-page transition guide should help facilitate the transition of patients with DS to the adult HCS and should be given to families as well as adult health care providers that may not be familiar with DS.

Safety and Tolerability of Transdermal Cannabidiol Gel in Children With Developmental and Epileptic Encephalopathies: A Nonrandomized Controlled Trial

IMPORTANCE

Developmental and epileptic encephalopathies (DEEs) are the most severe group of drug-resistant epilepsies. Alternatives to oral therapies are urgently needed to reduce seizures and improve developmental outcomes and comorbidities in this medically complex population.

OBJECTIVE

To assess the safety and tolerability of cannabidiol (CBD) transdermal gel in children with DEEs and to evaluate seizure frequency, sleep, and quality of life.

DESIGN, SETTING, AND PARTICIPANTS

This nonrandomized controlled trial was conducted in 2 centers in Australia and New Zealand from April 2018 to July 2019. Children and adolescents aged 3 to 18 years with DEEs who were receiving a stable regimen of 1 to 4 antiseizure medications were eligible for this study. After 1-month baseline and titration periods, patients entered a 5.5-month flexible-dosing maintenance period for a total of 6.5 months of treatment. Data were analyzed throughout the 6.5-month treatment period.

INTERVENTIONS

Twice-daily applications of CBD transdermal gel at doses of 125 to 500 mg for 6.5 months.

MAIN OUTCOMES AND MEASURES

Safety and tolerability assessments included adverse events (AEs) and examination of skin. The outcome for seizures was the median percentage change from baseline in monthly (28-day) seizure frequency of focal impaired awareness seizures (FIAS) and tonic-clonic seizures (TCS) over 6.5 months.

RESULTS

Of 48 patients (mean [SD] age, 10.5 [3.8] years; 26 [54%] boys), 29 (60%) had at least 1 treatment-related AE over 6.5 months; 44 of 46 treatment-related AEs (96%) were mild or moderate. Treatment-related AEs that occurred in at least 5% of patients were application-site dryness, application-site pain, and somnolence (each reported by 4 patients [8%]). The only treatment-related gastrointestinal AE was diarrhea, reported in a single patient. CBD treatment was associated with reductions in FIAS and TCS frequency. Analysis of the 33 patients with FIAS and TCS showed a median (interquartile range) monthly reduction in seizures of 58% (-5.3% to 81.8%) at 5 months and 43.5% (-23.8% to 57.5%) over the entire 6.5-month study period. Parents and caregivers noted improvements in social or interpersonal engagement and irritability (33 of 43 [77%] participants); alertness, energy, and sleep (23 of 43 [53%]); and cognition or concentration (20 of 43 [47%]).

CONCLUSIONS AND RELEVANCE

In this study, CBD transdermal gel was safe, well tolerated, and was associated with reductions in FIAS and TCS frequency and disease burden.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: ACTRN12618000516280.

Deconstructing Dravet syndrome neurocognitive development: A scoping review

Dravet syndrome (DS) is a rare severe epilepsy syndrome associated with slowed psychomotor development and behavioral disorders from the second year onward in a previously seemingly normal child. Among cognitive impairments, visuospatial, sensorimotor integration, and expressive language deficits are consistently reported. There have been independent hypotheses to deconstruct the typical cognitive development in DS (dorsal stream vulnerability, cerebellar-like pattern, sensorimotor integration deficit), but an encompassing framework is still lacking. We performed a scoping review of existing evidence to map the current understanding of DS cognitive and behavioral developmental profiles and to summarize the evidence on suggested frameworks. We searched PubMed, Scopus, PsycInfo, and MEDLINE to identify reports focusing on cognitive deficits and/or behavioral abnormalities in DS published between 1978 and March 15, 2020. We followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines. Twenty-one reports were selected and tabulated by three independent reviewers based on predefined data extraction and eligibility forms. Eighteen reports provided assessments of global intelligence quotients with variable degrees of cognitive impairment. Eleven reports analyzed single subitems contribution to global cognitive scores: these reports showed consistently larger impairment in performance scales compared to verbal ones. Studies assessing specific cognitive functions demonstrated deterioration of early visual processing, fine and gross motor abilities, visuomotor and auditory-motor integration, spatial processing, visuo-attentive abilities, executive functions, and expressive language. Behavioral abnormalities, reported from 14 studies, highlighted autistic-like traits and attention and hyperactivity disorders, slightly improving with age. The cognitive profile in DS and some behavioral and motor abnormalities may be enclosed within a unified theoretical framework of the three main hypotheses advanced: a pervasive sensorimotor integration deficit, encompassing an occipito-parietofrontal circuit (dorsal stream) dysfunction and a coexistent cerebellar deficit.

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.

Cognitive, behavioral, and social functioning in children and adults with Dravet syndrome

AIM

The objective of the study was to delineate the cognitive, behavioral, psychological, and social functioning of individuals with Dravet syndrome.

METHOD

Cognitive, behavioral, and social functioning were assessed in patients with Dravet syndrome by comprehensive, age-appropriate standardized neuropsychological testing. Primary caregivers completed standardized measures regarding participants' behavior, psychological status, adaptive functioning, and social skills, including their involvement with intervention services.

RESULTS

The cohort comprised 45 patients, aged 2-30 years. Intellectual functioning ranged from average intellect to profound intellectual disability, with a decrease in cognitive and adaptive functioning with age. Only 6 children were able to complete the entire neuropsychological battery and showed a range of cognitive profiles. Five of 6 participants scored within the average range on Affect Recognition and 5/6 on Motor Free Visual Perception tests. Twenty-one (58%) participants had deficits in social skills and 18/27 (67%) in social communication, with 10 participants, who did not yet have a diagnosis of autism spectrum disorder (ASD), screening positive for social communication deficits. Behavioral problems were frequently reported, with attention problems in 24 (65%) and atypicality in 25 (70%). Despite this, parents reported that psychological services were the least utilized health interventions.

CONCLUSIONS

Cognitive functioning varies markedly in individuals with Dravet syndrome, with some patients demonstrating global impairment while others have a discordant neuropsychological profile. Behavioral, psychological, social problems, and ASD are common. Social deficits should be reviewed to identify those who warrant ASD assessment. Early identification of behavioral and psychological disorders and targeted use of psychological intervention are essential components of holistic care in Dravet syndrome.

Intellectual functioning and behavior in Dravet syndrome: A systematic review

BACKGROUND

Dravet syndrome (DS) is a developmental and epileptic encephalopathy with onset in the first year of life. At onset, the child displays normal development, but during the second year of life, stagnation/slowing of neurodevelopment is seen. In addition to difficulties with intellectual development, many children display behavioral problems including autistic features, and difficulties with attention and hyperactivity.

AIM

The aim of the present study was to systematically review studies that have focused on the prevalence of cognitive/developmental quotients (DQs) consistent with intellectual disability (ID), deficits in adaptive behavior, autism spectrum disorder (ASD), attention-deficit hyperactivity disorder (ADHD), and behavioral difficulties. A secondary aim was to consider possible factors associated with intellectual and behavioral outcomes in individuals with DS.

METHOD

A systematic review using PubMed and Scopus following the Preferred Reporting Items for Systematic Review (PRISMA) guidelines was conducted on the 24th of September 2019. Study quality was rated by two researchers using the National Institutes of Health (NIH) Quality assessment tools.

RESULT

Twenty-nine studies met inclusion criteria. The pooled prevalence of ID was 86% (range across studies: 50%-100%). The pooled prevalence for ASD was 31%. The mean level of adaptive behavior was more than 2 standard deviations (SDs) below average. The prevalence of behavioral difficulties on standardized instruments ranged between 37% and 100%. The only factor consistently associated with lower cognitive scores was age with older children having significantly lower cognitive scores than younger children. For behavioral difficulties, the most consistent association was with low health-related quality of life (HRQoL) with better HRQoL associated with fewer behavioral difficulties. Study quality was almost universally poor or fair - 15/29 studies were rated 'poor', 13/29 studies were 'fair', and 1 was 'good'.

DISCUSSION

The prevalence of cognitive scores consistent with ID is very high in DS. Many patients also have significant deficits in adaptive behavior highlighting that the majority of patients with DS will meet criteria for ID. The prevalence of ASD would also appear to be higher than the general population but studies show a wide range. Behavioral difficulties are common, but most studies have not used instruments adapted to patients with low intelligence quotient/DQ (IQ/DQ). No study used standardized instruments to assess ADHD. Few studies have used comprehensive statistical methods to evaluate possible factors associated with worse cognitive and behavioral outcome.

CONCLUSION

It should be routine to screen for cognitive and behavioral difficulties for all patients with DS. There is a need for more robust studies regarding intellectual and behavioral disorders in patients with DS. These should be large population-based or multinational studies that employ standardized instruments.

Dravet syndrome: Early electroclinical findings and long-term outcome in adolescents and adults

To describe the outcome of Dravet syndrome (DS) in adolescents and adults we conducted a longitudinal retrospective study of two independent cohorts of 34 adolescents (group 1) and 50 adults (group 2). In both cohorts, we collected information about genetic mutation, and semiology of seizures at onset and during disease course. At the last evaluation, we considered the following features: epilepsy (distinguishing myoclonic/complete and nonmyoclonic/incomplete phenotype), neurologic signs, intellectual disability (ID), and behavioral disorders. Moreover, in both cohorts, we performed a correlation analysis between early characteristics of the disease and the outcome of DS with regard to seizure persistence, ID, behavioral disorder, and neurologic impairment at last evaluation. Group 1 includes 22 adolescents with complete form of DS and 12 with incomplete form; group 2 includes 35 adults with complete form and 15 with incomplete form. The seizures persisted in 73.6% of adolescents and in 80% of adults, but epilepsy severity progressively decreased through age. Seizure persistence correlated with the complete phenotype and with the occurrence of reflex seizures. At last evaluation, ID was moderate or severe in 70.5% of adolescents and in 80% of adults. The most severe cognitive and motor impairment was observed in patients with persisting seizures. The severity of cognition, language, and neurologic impairment at last evaluation correlated statistically with the complete phenotype. The study confirms that the global outcome of DS is poor in most cases, albeit epilepsy severity decreases throughout adulthood. The improvement of epilepsy throughout ages is not associated with improvement in intellectual abilities and motor skills; this confirms that the unfavorable outcome is not a pure consequence of epilepsy.

Adolescent behavioral abnormalities in a Scn1a+/- mouse model of Dravet syndrome

Dravet syndrome is an intractable pediatric epilepsy associated with SCN1A mutations. In addition to having a large seizure burden and a reduced lifespan, patients with Dravet syndrome also exhibit delays in reaching normal developmental milestones in attentional, emotional, and cognitive function. These developmental delays manifest in autistic-like social withdrawal and compulsive behavior. Additionally, cognitive impairments including deficits in sensorimotor processing and memory function are present. Several mouse models utilizing heterozygous deletion of Scn1a (Scn1a^+/- mice) have been generated that recapitulate many aspects of Dravet syndrome. Studies in these mouse models of Dravet syndrome have characterized behavioral phenotypes in adult mice. In the present study, we characterized the behavioral phenotype of Scn1a^+/- mice generated by targeted deletion of Scn1a exon 1 (Scn1a^tm1Kea) during adolescence. Identifying behavioral deficits in adolescent mice would more closely model the early onset of attentional, emotional, and cognitive delays observed in patients with Dravet syndrome. The behaviors of adolescent Scn1a^+/- and wildtype (WT) mice were compared across several behavioral domains. We assessed motor function (open-field test), sociability and social recognition memory (three-chambered social preference and social interaction tests), memory function (novel object recognition, Barnes maze, fear conditioning paradigm), anxiety-related behavior (elevated plus maze and open-field thigmotaxis), startle reflex and sensorimotor gating (prepulse inhibition of startle (PPI) tests), and repetitive compulsive behavior (marble burying test). Adolescent Scn1a^+/- mice exhibited normal locomotor activity, marble burying behavior, sociability, and sensorimotor gating. However, adolescent Scn1a^+/- mice displayed increased anxiety-related thigmotactic behavior, atypical fear expression, blunted acoustic startle responses, and impaired social recognition and spatial memory. Our results show that Scn1a^+/- mice display various behavioral impairments during adolescence, which provides a foundation for testing early intervention therapies targeting developmental delays modeled in Dravet syndrome mice.

Delayed maturation of GABAergic signaling in the Scn1a and Scn1b mouse models of Dravet Syndrome

Dravet syndrome (DS) is a catastrophic developmental and epileptic encephalopathy characterized by severe, pharmacoresistant seizures and the highest risk of Sudden Unexpected Death in Epilepsy (SUDEP) of all epilepsy syndromes. Here, we investigated the time course of maturation of neuronal GABAergic signaling in the Scn1b-/- and Scn1a+/- mouse models of DS. We found that GABAergic signaling remains immature in both DS models, with a depolarized reversal potential for GABAA-evoked currents compared to wildtype in the third postnatal week. Treatment of Scn1b-/- mice with bumetanide resulted in a delay in SUDEP onset compared to controls in a subset of mice, without prevention of seizure activity or amelioration of failure to thrive. We propose that delayed maturation of GABAergic signaling may contribute to epileptogenesis in SCN1B- and SCN1A-linked DS. Thus, targeting the polarity of GABAergic signaling in brain may be an effective therapeutic strategy to reduce SUDEP risk in DS.

Autism spectrum disorder and cognitive profile in children with Dravet syndrome: Delineation of a specific phenotype

OBJECTIVE

We aimed to assess a cohort of young patients with Dravet syndrome (DS) for intellectual disability (ID) and autism spectrum disorder (ASD) using standardized tools and parental questionnaires to delineate their specific profiles.

METHODS

We included 35 patients with DS aged 24 months to 7 years, excluding patients with a developmental age (DA) <18 months (n = 5). We performed specific tests adapted for ID (Psychoeducational Profile, Third Edition [PEP-3]), in addition to the Child Development Inventory (CDI) and Vineland Adaptive Behavior Scales, Second Edition (VABS-II) questionnaires. We used 2 standardized tools for ASD: the Autism Diagnostic Observation Schedule, Second Edition (ADOS-2) and the Autism Diagnostic Interview-Revised (ADI-R). We compared the with parental questionnaires and the VABS-II, and with ASD characteristics.

RESULTS

PEP-3 subscales showed pathologic development in all but one patient (97%): ID in 23 of 30 (77%), and borderline cognitive functioning in 6 of 30 (22%). Eleven patients (39%) had ASD and 2 (7%) had a Social Communication Disorder (SCD) diagnosis. We found no difference between PEP-3 and CDI categorization except for fine motor skills. We found significant negative correlations between ADOS-2 and PEP-3 for the majority of scores. For patients aged older than 50 months, 2 groups emerged (ASD/no ASD) with significant difference in DA. The logistic regression for ASD diagnosis explained by VABS-II showed a significant effect for Socialization, Motor Skills, and Adaptive Behavior.

SIGNIFICANCE

We found a high prevalence of ID in patients with DS. ID is characterized by expressive and comprehensive communication deficits in addition to visuospatial difficulties. ASD showed a specific profile with a relative preservation of social skills, emphasizing a possible underdiagnosis. Parental questionnaires can provide a good assessment of cognitive profile and might allow the difficulty of addressing cognitive scales in DS to be overcome. The profile of ID and ASD should help to establish early adapted rehabilitation programs and emphasizes the global need for care beyond seizures in DS and other developmental epileptic encephalopathies.

Toward the Language Oscillogenome

Language has been argued to arise, both ontogenetically and phylogenetically, from specific patterns of brain wiring. We argue that it can further be shown that core features of language processing emerge from particular phasal and cross-frequency coupling properties of neural oscillations; what has been referred to as the language ‘oscillome.’ It is expected that basic aspects of the language oscillome result from genetic guidance, what we will here call the language ‘oscillogenome,’ for which we will put forward a list of candidate genes. We have considered genes for altered brain rhythmicity in conditions involving language deficits: autism spectrum disorders, schizophrenia, specific language impairment and dyslexia. These selected genes map on to aspects of brain function, particularly on to neurotransmitter function. We stress that caution should be adopted in the construction of any oscillogenome, given the range of potential roles particular localized frequency bands have in cognition. Our aim is to propose a set of genome-to-language linking hypotheses that, given testing, would grant explanatory power to brain rhythms with respect to language processing and evolution.

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).

Quality of life and comorbidities associated with Dravet syndrome severity: a multinational cohort survey

AIM

To test the hypothesis that higher seizure burden in Dravet syndrome is associated with increased comorbidities and lower quality of life (QoL) in a large cohort of patients with Dravet syndrome and their caregivers in Europe.

METHOD

An extensive survey of caregivers of patients with Dravet syndrome on experiences of diagnosis, seizure burden, management, social and financial impact, and health services use was administered online in 10 languages.

RESULTS

The survey received 584 unique responses from caregivers of paediatric (83%) and adult (17%) patients with Dravet syndrome (aged <1-48y). Despite broadly following current treatment guidance, less than 10% of patients were seizure free in the previous 3 months. Nearly all (99.6%) patients aged 5 years or older experienced at least one or more motor, speech, learning, or behavioural impairment. High seizure frequency was related to more reports of emergency treatment, comorbidities, and a lower QoL (as measured by the standardized instrument EQ-5D-5L). If not diagnosed at the first instance, the majority (83%) of adults, but less than 20% of 6- to 11-year-olds were diagnosed after 4 or more years.

INTERPRETATION

Patients with Dravet syndrome with the highest current seizure frequency suffer from more comorbidities and have a lower QoL. Therefore, more effective antiepileptic treatments are needed.

WHAT THIS PAPER ADDS

The survey captured about 15% of all patients with Dravet syndrome in Europe. Less than 10% of patients had current seizure freedom. Patients with a high current seizure burden have more comorbidities and lower quality of life.

Cognitive and Social Outcomes of Epileptic Encephalopathies

The term "epileptic encephalopathy" denotes a disorder in which seizures or frequent interictal discharges exacerbate neurocognitive dysfunction beyond what would be expected on the basis of underlying etiology. However, many underlying causes of epileptic encephalopathy also result in neurocognitive deficits, and it can be challenging to discern to what extent these deficits can be improved with better seizure control. Additionally, as seizures in these conditions are typically refractory, children are often exposed to high doses of multiple antiepileptic drugs which further exacerbate these comorbidities. This review will summarize the neurocognitive and social outcomes in children with various epileptic encephalopathies. Prompt, accurate diagnosis of epilepsy syndrome and etiology allows selection of optimal therapy to maximize seizure control, limiting the impact of ongoing seizures and frequent epileptiform abnormalities on the developing brain. Furthermore, mandatory screening for comorbidities allows early recognition and focused therapy for these commonly associated conditions to maximize neurocognitive outcome.