Definition and diagnostic criteria of sleep-related hypermotor epilepsy

Rhythmic movements in sleep disorders and in epileptic seizures during sleep

Rhythmic movements during sleep may occur in the context of physiological sleep-related motor activity or be part of sleep-related movement disorders such as bruxism, periodic limb movement disorder, restless legs syndrome, and sleep-related rhythmic movement disorder. They may also characterize some frontal or temporal nocturnal seizures of sleep-related hypermotor epilepsy, or be considered as part of NREM parasomnias, especially sleepwalking, sexsomnia or sleep-related eating disorder, or REM-related behaviors such as REM behavior disorder or complex movements associated with pediatric narcolepsy type I.

In most cases rhythmic movements, especially when complex and long in duration, are related to different levels of arousal from sleep with recurrence of ancestral motor sequences promoted by central pattern generators in the brainstem, generally activated by the arousal process.

A differential diagnosis between physiological events and pathological movement disorders, and between the latter and sleep-related epilepsy is critical to provide optimal treatment and an accurate prognosis. Specific treatment options for the aforementioned disorders are beyond the scope of this article.

The clinical phenotypes and genetic characteristics of seven epilepsy patients related to heterozygous DEPDC5 variants in China

Objective

DEPDC5 together with NPRL2 and NPRL3 forms the GATOR1 which plays an important role in the the mechanistic target of rapamycin (mTOR) pathway. Deregulation of mTOR signalling has been associated to various neurological conditions, including epilepsy. Variants in the gene encoding GATOR1 complex, especially in DEPDC5, have been implicated in the pathogensis of several focal epilepsies. While there was little report on the electroencephalogram (EEG) feature of DEPDC5 related epilepsy, we decided to investigate the specific EEG pattern and the prognosis of DEPDC5 related epilepsy.

Methods

The records of 546 epilepsy patients with unknown causes who were admitted in Xijing Hospital and underwent whole exome sequencing (WES) from 2015 to 2019 were retrospectively reviewed. Finally, the clinical data of these 7 patients with DEPDC5 variants were collected in this study. We analyzed their clinical manifestations, EEG and magnetic resonance imaging (MRI).

Results

Seven DEPDC5 variants, including six novel mutations, were identified in seven individuals with focal epilepsy. Among these patients, one had family history. Four showed specific interictal EEG patterns, periodic-like sharp waves or spike waves, were found in four patients. Five out of seven patients (71.4%) were well-controlled by anti-epilepsy drugs while two patients with sleep-related hypermotor epilepsy had either drug resistance or relapse of epilepsy.

Conclusion

DEPDC5 variants were related to focal epilepsy in patients with or without family history. The EEG abnormalities of DEPDC5 related epilepsy were heterogeneous among different patients, while periodic-like sharp waves or spike waves might be the most characteristic interictal EEG pattern for DEPDC5 related epilepsies. In this study the prognosis of DEPDC5 related epilepsy was similar to other epilepsies. DEPDC5 variants may not predict the prognosis so far.

Abnormal behaviors during sleep from the viewpoint of sleep epileptology: current and future perspectives on diagnosis

Abnormal behaviors during sleep (ABDS) exhibit a myriad of symptoms. Their underlying diseases are also diverse, which include NREM/REM-related parasomnias, epilepsy and mental disorders. Since ABDS may severely affect a patient’s quality of life, giving an early and accurate diagnosis of the underlying disease (by analyzing video-polysomnographic data during the manifestation of ABDS) is of great importance. However, accurate diagnosis of ABDS is rather difficult. Recently it has been suggested that the pathology of (NREM/REM-related) parasomnias and epilepsy are closely related. In order to unravel the pathophysiological substrate of ABDS, it is essential to develop a novel approach based on sleep epileptology, a field which targets the interface between sleep medicine and epileptology.

Therapy in Sleep-Related Hypermotor Epilepsy (SHE)

PURPOSE OF REVIEW

The purpose of this review is to summarize and discuss current options and new advances in the treatment of sleep-related hypermotor epilepsy (SHE), focusing on pharmacological and surgical treatments.

RECENT FINDINGS

Carbamazepine (CBZ) has traditionally been regarded as the first-line treatment option in SHE patients. In patients showing an unsatisfactory response to monotherapy, topiramate (TPM), lacosamide (LCM) and acetazolamide (ACZ) could be reasonable add-on strategies. The increasing understanding of the role of neuronal nicotinic acetylcholine receptor (nAChR) in SHE pathophysiology has led to the evaluation of compounds able to modulate this receptor system, including nicotine patches and fenofibrate. Despite polytherapy with two or more antiepileptic drugs (AEDs), about one-third of SHE patients suffer from drug-resistant seizures. In selected drug-resistant patients, epilepsy surgery is a therapeutic approach that offers high probability of recovery, with up to two-third of patients becoming seizure-free after resection of the epileptogenic zone. An evidence-based approach from randomized placebo-controlled trials in SHE patients is lacking, and current treatment recommendations are based only on case reports and small series. Furthermore, most of these case reports and case series involve patients with a known genetic defect, which only accounts for a small proportion of SHE patients. Therefore, a prospective study in a large cohort of sporadic SHE patients is necessary in order to provide clinicians with an evidence-based treatment for this rare form of epilepsy. An early and effective anti-epileptic treatment is mandatory for SHE patients, in order to prevent the risk of increasing seizure frequency throughout the disease course with relevant impact on patients' cognitive profile and daytime performances.

Advances in genetic testing and optimization of clinical management in children and adults with epilepsy

Introduction: Epileptic disorders are a heterogeneous group of medical conditions with epilepsy as the common denominator. Genetic causes, electro-clinical features, and management significantly vary according to the specific condition.Areas covered: Relevant diagnostic advances have been achieved thanks to the advent of Next Generation Sequencing (NGS)-based molecular techniques. These revolutionary tools allow to sequence all coding (whole exome sequencing, WES) and non-coding (whole genome sequencing, WGS) regions of human genome, with a potentially huge impact on patient care and scientific research.Expert opinion: The application of these tests in children and adults with epilepsy has led to the identification of new causative genes, widening the knowledge on the pathophysiology of epilepsy and resulting in therapeutic implications. This review will explore the most recent advancements in genetic testing and provide up-to-date approaches for the choice of the correct test in patients with epilepsy.

Insights into the mechanisms of epilepsy from structural biology of LGI1-ADAM22

Epilepsy is one of the most common brain disorders, which can be caused by abnormal synaptic transmissions. Many epilepsy-related mutations have been identified in synaptic ion channels, which are main targets for current antiepileptic drugs. One of the novel potential targets for therapy of epilepsy is a class of non-ion channel-type epilepsy-related proteins. The leucine-rich repeat glioma-inactivated protein 1 (LGI1) is a neuronal secreted protein, and has been extensively studied as a product of a causative gene for autosomal dominant lateral temporal lobe epilepsy (ADLTE; also known as autosomal dominant partial epilepsy with auditory features [ADPEAF]). At least 43 mutations of LGI1 have been found in ADLTE families. Additionally, autoantibodies against LGI1 in limbic encephalitis are associated with amnesia, seizures, and cognitive dysfunction. Although the relationship of LGI1 with synaptic transmission and synaptic disorders has been studied genetically, biochemically, and clinically, the structural mechanism of LGI1 remained largely unknown until recently. In this review, we introduce insights into pathogenic mechanisms of LGI1 from recent structural studies on LGI1 and its receptor, ADAM22. We also discuss the mechanism for pathogenesis of autoantibodies against LGI1, and the potential of chemical correctors as novel drugs for epilepsy, with structural aspects of LGI1-ADAM22.

Sleep-related hypermotor epilepsy (SHE): Contribution of known genes in 103 patients

PURPOSE

Genetics of Sleep-related Hypermotor Epilepsy (SHE) includes mutations in several genes that cumulatively account for 30 % of families. This approximate estimate comes from different case-series, each focused on the screening of a single gene. We systematically investigated a large cohort of SHE patients to estimate the frequency of pathogenic variants in the main genes thus far implicated in this epilepsy syndrome.

METHODS

We selected familial and isolated cases diagnosed with clinical/confirmed SHE who underwent genetic analysis by comparable next generation sequencing (NGS) techniques (WES/ multigene epilepsy panel). The identified heterozygous variants were classified according to the American College of Medical Genetics and Genomics guidelines.

RESULTS

We included 103 SHE patients (M/F:61/42) who underwent NGS. Sixteen (15.5 %) were familial cases, 16.5 % had focal cortical dysplasia (FCD). We identified three pathogenic variants in CHRNA4 (2.9 %, CI: 0.6-8.3 %), two of whom novel; one pathogenic variant in KCNT1 (1 %, CI: 0.02-5.29 %); four loss-of-function variants in DEPDC5 (3.9 %, CI: 1.1-9.7 %), one of whom never reported; finally, one missense change in NPRL2 (1 %, CI: 0.02-5.29 %), already reported as pathogenic. Three out of the four patients with DEPDC5 variants had FCD.

CONCLUSIONS

The overall frequency of pathogenic variants in our SHE cohort was 8.7 %, 19 % and 7 % considering familial and sporadic cases, respectively. Pathogenic variants in the GATOR1-complex genes account for 5 % of the cases. DEPDC5 shows the highest variants frequency, especially in patients with genetic-structural etiology. From a practical perspective, analysis of this gene is recommended even in isolated cases, because of possible implications for patient management.

Polysomnographic features differentiating disorder of arousals from sleep-related hypermotor epilepsy

Objective

The differential diagnosis between sleep-related hypermotor epilepsy (SHE) and disorders of arousal (DOA) may be challenging. We analyzed the stage and the relative time of occurrence of parasomnic and epileptic events to test their potential diagnostic accuracy as criteria to discriminate SHE from DOA.

Methods

Video-polysomnography recordings of 89 patients with a definite diagnosis of DOA (59) or SHE (30) were reviewed to define major or minor events and to analyze their stage and relative time of occurrence. The “event distribution index” was defined on the basis of the occurrence of events during the first versus the second part of sleep period time. A group analysis was performed between DOA and SHE patients to identify candidate predictors and to quantify their discriminative performance.

Results

The total number of motor events (i.e. major and minor) was significantly lower in DOA (3.2 ± 2.4) than in SHE patients (6.9 ± 8.3; p = 0.03). Episodes occurred mostly during N3 and N2 in DOA and SHE patients, respectively. The occurrence of at least one major event outside N3 was highly suggestive for SHE (p = 2*e-13; accuracy = 0.898, sensitivity = 0.793, specificity = 0.949). The occurrence of at least one minor event during N3 was highly suggestive for DOA (p = 4*e-5; accuracy = 0.73, sensitivity = 0.733, specificity = 0.723). The “event distribution index” was statistically higher in DOA for total (p = 0.012) and major events (p = 0.0026).

Conclusion

The stage and the relative time of occurrence of minor and major motor manifestations represent useful criteria to discriminate DOA from SHE episodes.

Multiscale Functional Clustering Reveals Frequency Dependent Brain Organization in Type II Focal Cortical Dysplasia With Sleep Hypermotor Epilepsy

OBJECTIVE

A multiscale functional clustering approach is proposed to investigate the organization of the epileptic networks during different sleep stages and in relation with the occurrence of seizures.

METHOD

Stereo-electroencephalographic signals from seven pharmaco-resistant epileptic patients (focal cortical dysplasia type II) were analyzed. The discrete wavelet transform provided a multiscale framework on which a data-driven functional clustering procedure was applied, based on multivariate measures of integration and mutual information. The most interacting functional clusters (FCs) within the sampled brain areas were extracted.

RESULTS

FCs characterized by strongly integrated activity were observed mostly in the beta and alpha frequency bands, immediately before seizure onset and in deep sleep stages. These FCs generally included the electrodes from the epileptogenic zone. Furthermore, repeatable patterns were found across ictal events in the same patient.

CONCLUSION

In line with previous studies, our findings provide evidence of the important role of beta and alpha activity in seizures generation and support the relation between epileptic activity and sleep stages.

SIGNIFICANCE

Despite the small number of subjects included in the study, the present results suggest that the proposed multiscale functional clustering approach is a useful tool for the identification of the frequency-dependent mechanisms underlying seizure generation.

ADCY5-Related Dyskinesia: Improving Clinical Detection of an Evolving Disorder

BACKGROUND

The phenotypic spectrum of adenylyl cyclase 5 (ADCY5)-related disease has expanded considerably since the first description of the disorder in 1978 as familial essential chorea in a multiplex family.

OBJECTIVE

To examine recent advances in the understanding of ADCY5-related dyskinesia and outline a diagnostic approach to enhance clinical detection.

METHODS

A pragmatic review of the ADCY5 literature was undertaken to examine unique genetic and pathophysiological features as well as distinguishing clinical features.

RESULTS

With over 70 cases reported to date, the phenotype is recognized to be broad, although distinctive features include prominent facial dyskinesia, motor exacerbations during drowsiness or sleep arousal, episodic painful dystonic posturing increased with stress or illness, and axial hypotonia with delayed developmental milestones. Uncommon phenotypes include childhood-onset chorea, myoclonus-dystonia, isolated nongeneralized dystonia, and alternating hemiplegia.

CONCLUSION

The ongoing expansion in clinical features suggests that ADCY5 remains underdiagnosed and may account for a proportion of "idiopathic" hyperkinetic movement disorders. Enhanced understanding of its clinical features may help clinicians improve the detection of complex or uncommon cases.

The role of sleep-related cognitive functions in the spectrum of benign epilepsy with centro-temporal spikes

Heterogeneous cognitive deficits have been described in the spectrum of benign epilepsy with centro-temporal spikes, which strongly correlate with the intensity of interictal epileptiform discharges and its spreading, in particular during sleep, mostly within the perisylvian cognitive network. The aim of this review is to discuss current findings regarding the connection between sleep alterations and cognitive function in the spectrum of benign epilepsy with centro-temporal spikes. A longer sleep onset latency is the only evident sleep macrostructure alteration reported in the spectrum of benign epilepsy with centro-temporal spikes. On a microstructural level, a higher spike count of descending compared to ascending slopes of sleep cycles, an impairment of slow wave downscaling, and amplitude and slope of slow waves were found in the spectrum of benign epilepsy with centro-temporal spikes. Moreover, children with benign epilepsy with centro-temporal spikes had a reduced non-rapid eye movement sleep instability, in terms of cyclic alternating pattern, similar to that found in children with attention-deficit hyperactivity disorders and in children with obstructive sleep apnea and centro-temporal spike during sleep. Children with benign epilepsy with centro-temporal spikes have a known comorbidity with attention-deficit hyperactivity disorders and obstructive sleep apnea.Conclusion: Considering the common sleep microstructure alterations, the presence of attention deficit and hyperactivity and/or sleep apnea may be a considered warning sign in the case of benign epilepsy with centro-temporal spikes. What is Known: • Sleep related-cognitive deficits have been described in the spectrum of benign epilepsy with centro-temporal spikes. The degree of sleep alterations may predict the neurocognitive outcome, and help clinicians to choose the right treatment. What is New: • Considering the common sleep microstructure alterations, attention deficit and sleep apnea, may be a considered warning signs.

Seizures and movement disorders: phenomenology, diagnostic challenges and therapeutic approaches

Seizures and movement disorders (MDs) are distinct neurological conditions presenting with abnormal movements. Despite sharing an overlap in phenomenology, these movements have different origins. In order to explore the overlaps and the narrow boundaries between these two conditions, we performed a review of the literature to explore the risk of seizures in MDs. We discussed the mimics and chameleons including MDs that look like seizure (eg, paroxysmal dyskinesia, status dystonicus) and seizures that look like MDs (eg, epilepsia partialis continua, nocturnal frontal lobe epilepsy). Additionally, we examined the therapeutic challenges as well as the anatomical and chemical pathways relevant in the interplay between epilepsy and MDs. Finally, we proposed an algorithm to guide clinicians towards the final diagnosis of conditions characterised by the co-occurrence of MDs and seizures.

Paroxysmal Movement Disorders: Recent Advances

PURPOSE OF REVIEW

Recent advancements in next-generation sequencing (NGS) have enabled techniques such as whole exome sequencing (WES) and whole genome sequencing (WGS) to be used to study paroxysmal movement disorders (PMDs). This review summarizes how the recent genetic advances have altered our understanding of the pathophysiology and treatment of the PMDs. Recently described disease entities are also discussed.

RECENT FINDINGS

With the recognition of the phenotypic and genotypic heterogeneity that occurs amongst the PMDs, an increasing number of gene mutations are now implicated to cause the disorders. PMDs can also occur as part of a complex phenotype. The increasing complexity of PMDs challenges the way we view and classify them. The identification of new causative genes and their genotype-phenotype correlation will shed more light on the underlying pathophysiology and will facilitate development of genetic testing guidelines and identification of novel drug targets for PMDs.

Clinical Features and Pathophysiology of Disorders of Arousal in Adults: A Window Into the Sleeping Brain

Introduction: Disorders of Arousal (DoA) are NREM parasomnias that have been typically regarded as self-limited childhood manifestations. It is now clear that DoA can persist in adults, often presenting with distinctive characteristics. So far, few studies have described the clinical course and characteristics of DoA in adulthood, therefore a large part of their semiology is ignored. The aim of this study is to describe the clinical manifestations of DoA in an adult population and to provide a pathophysiological interpretation of their features. Methods: We screened our database for all 1,600 adult (≥15 years) patients with sleep-related motor behaviors between 1995 and 2016. We identified 45 patients with typical DoA episodes, of whom a complete history, neurological examination and diagnostic video-polysomnography (VPSG) were available. All patients provided a detailed description of their episodes (with particular regards to semiology, frequency, and association with stressful life events) in different life periods. VPSG recordings were reviewed and DoA episodes were identified and assigned to three different categories according to their complexity. Results: Our population was composed of 45 adult patients ranging between 15 and 76 years. Sleepwalking was reported by 86% of patients, possibly associated with complex interactions with the environment and violent behaviors in 53% of cases; distressing mental contents were reported by 64%. Recall of the episodes was reported in 77% of patients. Non-restorative sleep was reported in 46% of patients. Stress was a potential episode trigger in 80% of patients. VPSG recordings documented 334 DoA episodes. According to our classification of motor patterns, 282 episodes (84%) were Simple Arousal Movements (SAMs), 34 (10%) Rapid Arousal Movements (RAMs) and 18 (5%) Complex Arousal Movements (CAMs). Discussion: Our study confirms that DoA in adulthood present with distinctive characteristics, such as non-restorative sleep, violence and complex, or bizarre behaviors. Alternative classifications of DoA based on motor patterns could be useful to characterize DoA episodes in adults, as different motor patterns often coexist in the same individual and minor episodes are more common but generally underreported by patients. Prospective studies are needed for a definitive characterization of DoA in adulthood throughout the life course.

Insights into sleep-related hyper-motor epilepsy: an Egyptian case series

Objective: Sleep-related hypermotor epilepsy (SHE) is a sleep-related focal epilepsy which is often misdiagnosed. Despite active pharmacological therapy in the management of this disorder, satisfactory seizure control still cannot be achieved. Therefore, the aim of the present study was to identify this disorder among people who were seeking medical advice at Cairo University Epilepsy Unit (CUEU), characterizing its clinical, electroencephalographic and imaging features besides identifying possible indicators of inadequate seizure control on drug-therapy. Patients and methods: This study was carried out on 26 patients with SHE who were subjected to detailed history taking and examination in addition to home video recording, video electroencephalographic (EEG) monitoring and brain imaging. Ictal semiology and EEGs were reviewed and analyzed by experienced neurologists. Results: SHE is an uncommon sleep-related focal epilepsy. In our series, median age of the patients was 18.5 years. It is characterized by being sporadic, with often frontal lobe seizure onset (14/26, 53.8%) and with occasional occurrence in wakefulness. Adolescence age at disease onset (11 years, 6-15), duration less than 1 min, clustering, lack of auras and often uninformative brain imaging (22/25, 88%) are all documented features. Moreover, it has a relatively poor outcome on pharmacological therapy (16/26, 61.5%). Longer disease duration (>4.5 years) was a significant feature of the patients exhibiting inadequate seizure control. Conclusions: Our data show relatively poor prognosis of SHE on medical therapy. Its outcome is significantly related to disease duration at the time of diagnosis. Abbreviation: SHE = Sleep related hypermotor epilepsy.

Contribution of ultrarare variants in mTOR pathway genes to sporadic focal epilepsies

Objective

We investigated the contribution to sporadic focal epilepsies (FE) of ultrarare variants in genes coding for the components of complexes regulating mechanistic Target Of Rapamycin (mTOR)complex 1 (mTORC1).

Methods

We collected genetic data of 121 Italian isolated FE cases and 512 controls by Whole Exome Sequencing (WES) and single-molecule Molecular Inversion Probes (smMIPs) targeting 10 genes of the GATOR1, GATOR2, and TSC complexes. We collapsed "qualifying" variants (ultrarare and predicted to be deleterious or loss of function) across the examined genes and sought to identify their enrichment in cases compared to controls.

Results

We found eight qualifying variants in cases and nine in controls, demonstrating enrichment in FE patients (P = 0.006; exact unconditional test, one-tailed). Pathogenic variants were identified in DEPDC5 and TSC2, both major genes for Mendelian FE syndromes.

Interpretation

Our findings support the contribution of ultrarare variants in genes in the mTOR pathway complexes GATOR and TSC to the risk of sporadic FE and a shared genetic basis between rare and common epilepsies. The identification of a monogenic etiology in isolated cases, most typically encountered in clinical practice, may offer to a broader community of patients the perspective of precision therapies directed by the underlying genetic cause.

CHRNA2 and Nocturnal Frontal Lobe Epilepsy: Identification and Characterization of a Novel Loss of Function Mutation

Mutations in genes coding for subunits of the neuronal nicotinic acetylcholine receptor (nAChR) have been involved in familial sleep-related hypermotor epilepsy (also named autosomal dominant nocturnal frontal lobe epilepsy, ADNFLE). Most of these mutations reside in CHRNA4 and CHRNB2 genes, coding for the α4 and β2 nAChR subunits, respectively. Two mutations with contrasting functional effects were also identified in the CHRNA2 gene coding for the α2 subunit. Here, we report the third mutation in the CHRNA2, found in a patient showing ADNFLE. The patient was examined by scalp EEG, contrast-enhanced brain magnetic resonance imaging (MRI), and nocturnal video-polysomnographic recording. All exons and the exon-intron boundaries of CHRNA2, CHRNA4, CHRNB2, CRH, KCNT1 were amplified and Sanger sequenced. In the proband, we found a c.754T>C (p.Tyr252His) missense mutation located in the N-terminal ligand-binding domain and inherited from the mother. Functional studies were performed by transient co-expression of α2 and α2^Tyr252His, with either β2 or β4, in human embryonic kidney (HEK293) cells. Equimolar amounts of subunits expression were obtained by using F2A-based multi-cistronic constructs encoding for the genes relative to the nAChR subunits of interest and for the enhanced green fluorescent protein. The mutation reduced the maximal currents by approximately 80% in response to saturating concentrations of nicotine in homo- and heterozygous form, in both the α2β4 and α2β2 nAChR subtypes. The effect was accompanied by a strong right-shift of the concentration-response to nicotine. Similar effects were observed using ACh. Negligible effects were produced by α2^Tyr252His on the current reversal potential. Moreover, binding of (±)-[³H]Epibatidine revealed an approximately 10-fold decrease of both K_d and B_max (bound ligand in saturating conditions), in cells expressing α2^Tyr252His. The reduced B_max and whole-cell currents were not caused by a decrease in mutant receptor expression, as minor effects were produced by α2^Tyr252His on the level of transcripts and the membrane expression of α2β4 nAChR. Overall, these results suggest that α2^Tyr252His strongly reduced the number of channels bound to the agonist, without significantly altering the overall channel expression. We conclude that mutations in CHRNA2 are more commonly linked to ADNFLE than previously thought, and may cause a loss-of-function phenotype.

Prenatal alcohol exposure and sleep-wake behaviors: exploratory and naturalistic observations in the clinical setting and in an animal model

INTRODUCTION

Clinical research and studies using animal models have revealed a complex and relatively under-explored interaction between prenatal alcohol exposure (PAE) and alterations in sleep-wake behaviors.

OBJECTIVES

To utilize a structured naturalistic observation-based methodology, consisting of descriptive elements, to provide insight into possible links between altered sleep and disruptive daytime presentations in children and adolescents with fetal alcohol spectrum disorder (FASD). To apply a similar structured behavioral observation protocol in a PAE animal model to compare outcomes from the experimental and clinical studies utilizing naturalistic observational methodology.

METHODS

Forty pediatric patients with FASD (1.8-17.5 yrs, median age 9.4 yrs) and chronic sleep problems were assessed. In the PAE animal model, male offspring from PAE, Pair-Fed (PF), and ad libitum-fed Control (C) groups (n = 8/group) were assessed in the juvenile/preadolescent (23-25 days of age) and adolescent/pubertal (35-36 days of age) periods.

RESULTS

In the clinical setting, we found that 95% of children with FASD showed disruptive or externalizing behaviors, 73% showed internalizing behaviors, 93% had circadian rhythm sleep disorders, all had chronic insomnia, and 85% had restless sleep, often with tossing/turning/kicking movements indicative of non-restorative sleep with hypermotor events. In the daytime, individuals showed excessive daytime sleepiness as well as hyperactive/hyperkinetic behaviors, an urge-to-move, and involuntary movements suggestive of hyperarousability. Alterations in sleep/wake behaviors in the PAE animal model paralleled the clinical data in many aspects, demonstrating greater sleep latencies, less total time asleep, more total time awake and longer awake bouts, more position changes, more time in transition, and longer transition bouts in PAE compared to PF and/or control animals.

CONCLUSIONS

Thus, our findings provide support for the power and validity of naturalistic observational paradigms in revealing dysregulated sleep-wake behaviors and their association and/or exacerbating relationship with day and nighttime behavioral problems, such as disruptive behaviors, externalizing and internalizing disorders, and daytime sleepiness.

Mild malformations of cortical development in sleep-related hypermotor epilepsy due to KCNT1 mutations

Mutations in the sodium‐activated potassium channel gene KCNT1 have been associated with nonlesional sleep‐related hypermotor epilepsy (SHE). We report the co‐occurrence of mild malformation of cortical development (mMCD) and KCNT1 mutations in four patients with SHE. Focal cortical dysplasia type I was neuropathologically diagnosed after epilepsy surgery in three unrelated MRI‐negative patients, periventricular nodular heterotopia was detected in one patient by MRI. Our findings suggest that KCNT1 epileptogenicity may result not only from dysregulated excitability by controlling Na+K+ transport, but also from mMCD. Therefore, pathogenic variants in KCNT1 may encompass both lesional and nonlesional epilepsies.

Adult NREM Parasomnias: An Update

Our understanding of non-rapid eye movement (NREM) parasomnias has improved considerably over the last two decades, with research that characterises and explores the causes of these disorders. However, our understanding is far from complete. The aim of this paper is to provide an updated review focusing on adult NREM parasomnias and highlighting new areas in NREM parasomnia research from the recent literature. We outline the prevalence, clinical characteristics, role of onset, pathophysiology, role of predisposing, priming and precipitating factors, diagnostic criteria, treatment options and medico-legal implications of adult NREM parasomnias.

Genetics of Focal Epilepsies: What Do We Know and Where Are We Heading?

This article is based on a lecture delivered at the 2017 American Epilepsy Society Annual Meeting and provides an overview of the growing evidence supporting the strong genetic contribution to focal epilepsies. This also discusses how advances in the molecular genetics of focal epilepsies are rapidly translating to routine clinical care.

Circadian rhythm and epilepsy

Advances in diagnostic technology, including chronic intracranial EEG recordings, have confirmed the clinical observation of different temporal patterns of epileptic activity and seizure occurrence over a 24-h period. The rhythmic patterns in epileptic activity and seizure occurrence are probably related to vigilance states and circadian variation in excitatory and inhibitory balance. Core circadian genes BMAL1 and CLOCK, which code for transcription factors, have been shown to influence excitability and seizure threshold. Despite uncertainties about the relative contribution of vigilance states versus circadian rhythmicity, including circadian factors such as seizure timing improves sensitivity of seizure prediction algorithms in individual patients. Improved prediction of seizure occurrence opens the possibility for personalised antiepileptic drug-dosing regimens timed to particular phases of the circadian cycle to improve seizure control and to reduce side-effects and risks associated with seizures. Further studies are needed to clarify the pathways through which rhythmic patterns of epileptic activity are generated, because this might also inform future treatment options.

Sleep Related Epilepsy and Pharmacotherapy: An Insight

In the last several decades, sleep-related epilepsy has drawn considerable attention among epileptologists and neuroscientists in the interest of new paradigms of the disease etiology, pathogenesis and management. Sleep-related epilepsy is nocturnal seizures that manifest solely during the sleep state. Sleep comprises two distinct stages i.e., non-rapid eye movement (NREM) and rapid eye movement (REM) that alternate every 90 min with NREM preceding REM. Current findings indicate that the sleep-related epilepsy manifests predominantly during the synchronized stages of sleep; NREM over REM stage. Sleep related hypermotor epilepsy (SHE), benign partial epilepsy with centrotemporal spikes or benign rolandic epilepsy (BECTS), and Panayiotopoulos Syndrome (PS) are three of the most frequently implicated epilepsies occurring during the sleep state. Although some familial types are described, others are seemingly sporadic occurrences. In the present review, we aim to discuss the predominance of sleep-related epilepsy during NREM, established familial links to the pathogenesis of SHE, BECTS and PS, and highlight the present available pharmacotherapy options.

Postnatal Changes in K+/Cl- Cotransporter-2 Expression in the Forebrain of Mice Bearing a Mutant Nicotinic Subunit Linked to Sleep-Related Epilepsy

The Na+/K+/Cl- cotransporter-1 (NKCC1) and the K+/Cl- cotransporter-2 (KCC2) set the transmembrane Cl- gradient in the brain, and are implicated in epileptogenesis. We studied the postnatal distribution of NKCC1 and KCC2 in wild-type (WT) mice, and in a mouse model of sleep-related epilepsy, carrying the mutant β2-V287L subunit of the nicotinic acetylcholine receptor (nAChR). In WT neocortex, immunohistochemistry showed a wide distribution of NKCC1 in neurons and astrocytes. At birth, KCC2 was localized in neuronal somata, whereas at subsequent stages it was mainly found in the somatodendritic compartment. The cotransporters' expression was quantified by densitometry in the transgenic strain. KCC2 expression increased during the first postnatal weeks, while the NKCC1 amount remained stable, after birth. In mice expressing β2-V287L, the KCC2 amount in layer V of prefrontal cortex (PFC) was lower than in the control littermates at postnatal day 8 (P8), with no concomitant change in NKCC1. Consistently, the GABAergic excitatory to inhibitory switch was delayed in PFC layer V of mice carrying β2-V287L. At P60, the amount of KCC2 was instead higher in mice bearing the transgene. Irrespective of genotype, NKCC1 and KCC2 were abundantly expressed in the neuropil of most thalamic nuclei since birth. However, KCC2 expression decreased by P60 in the reticular nucleus, and more so in mice expressing β2-V287L. Therefore, a complex regulatory interplay occurs between heteromeric nAChRs and KCC2 in postnatal forebrain. The pathogenetic effect of β2-V287L may depend on altered KCC2 amounts in PFC during synaptogenesis, as well as in mature thalamocortical circuits.

Epilepsy genetics: Current knowledge, applications, and future directions

The rapid pace of disease gene discovery has resulted in tremendous advances in the field of epilepsy genetics. Clinical testing with comprehensive gene panels, exomes, and genomes are now available and have led to higher diagnostic rates and insights into the underlying disease processes. As such, the contribution to the care of patients by medical geneticists, neurogeneticists and genetic counselors are significant; the dysmorphic examination, the necessary pre- and post-test counseling, the selection of the appropriate next-generation sequencing-based test(s), and the interpretation of sequencing results require a care provider to have a comprehensive working knowledge of the strengths and limitations of the available testing technologies. As the underlying mechanisms of the encephalopathies and epilepsies are better understood, there may be opportunities for the development of novel therapies based on an individual's own specific genotype. Drug screening with in vitro and in vivo models of epilepsy can potentially facilitate new treatment strategies. The future of epilepsy genetics will also probably include other-omic approaches such as transcriptomes, metabolomes, and the expanded use of whole genome sequencing to further improve our understanding of epilepsy and provide better care for those with the disease.

Ictal signs in tuberous sclerosis complex: Clinical and video-EEG features in a large series of recorded seizures

Epilepsy is the most common neurological symptom in tuberous sclerosis complex (TSC), occurring in 72-85% of affected individuals. Despite the large number of patients reported, their electroclinical phenotype has been rarely described. We analyzed seizure semiology through ictal video-electroencephalography (V-EEG) recordings in a large series of patients. In this multicenter study, we reviewed V-EEGs of 51 patients: ictal recordings were analyzed in correlation with their clinical variables. The median age of epilepsy onset was six months (one day-16 years), with onset in the first year of life in 71% patients (36/51), in 10 of them during the neonatal period. Sixty-five percent of patients (33/51) experienced epileptic spasms in their life, with late-onset (>two years) in five; 42% of the epileptic spasms persisted after age two years, despite the onset in the first year of life. We identified four different electroclinical subsets: focal epilepsy (35%, 18/51), Lennox-Gastaut Syndrome evolution (27%, 14/51), focal seizures with persisting spasms (33%, 17/51), and spasms only (4%, 2/51). We reviewed 45 focal seizures, 13 clusters of epileptic spasms, and seven generalized seizures. In 12 patients, we recorded different seizure types. In 71% of the focal seizures (32/45), the ictal pattern was focal without diffusion. In 38% of the patients (5/13) epileptic spasms were related to typical diffuse slow wave pattern associated with superimposed fast activity, with focal predominance. Focal seizures and focal spasms resulted as the most frequent seizure types in TSC. Seizure onset was variable but showing a predominant involvement of the frontocentral regions (40%). Discrete clinical signs characterized the seizures, and behavioral arrest was the predominant first clinical objective sign. Epileptic spasms were a typical presentation at all ages, frequently asymmetrical and associated with lateralizing features, especially in older patients.

Co-morbid sleep disorders and epilepsy: A narrative review and case examples

Co-morbid sleep disorders, including sleep apnea, insomnia, restless legs syndrome, and the parasomnias, occur frequently in people with epilepsy. This article reviews the cardinal presenting symptoms and diagnostic features of each of these disorders to enable epileptologists to readily screen and identify sleep co-morbidities in their patients. It summarizes current evidence concerning the reciprocal relationship between sleep disturbances and epilepsy and available treatment options for common sleep disorders in people with epilepsy. Several illustrative cases demonstrate the practical consequences of co-morbid sleep disorders in epilepsy patients and suggest diagnostic and treatment approaches that may improve daytime functioning, alertness, quality of life, and seizure burden.

Diagnostic Approach and Investigation in Sleep Medicine

PURPOSE OF REVIEW

This article provides a clinical approach to the appropriate investigation and diagnosis of sleep disorders commonly seen by neurologists.

RECENT FINDINGS

Home sleep apnea testing in appropriate situations can replace laboratory polysomnography in many cases of uncomplicated sleep apnea. Multiple sleep latency tests must be performed meticulously and interpreted in the clinical setting to avoid overdiagnoses of narcolepsy. Human leukocyte antigen testing has limited utility in establishing a diagnosis of narcolepsy because a positive test has low specificity. Rapid eye movement (REM) sleep behavior disorder is frequently the first manifestation of an evolving synucleinopathy, and a careful history and neurologic examination are needed to determine other early features of these disorders.

SUMMARY

A meticulous history from the patient, supplemented by collateral history from an observer, is essential to establishing the diagnosis of sleep disorders. Judicious supplementary use of investigations, such as laboratory polysomnography, home sleep apnea testing, wrist actigraphy, and multiple sleep latency tests, can confirm the correct diagnosis. This article describes an approach to the sleepy patient, the patient with neuromuscular disease and possible sleep-disordered breathing, the patient with restless legs syndrome, and young and older patients with abnormal movements during sleep.

Sleep-related motor and behavioral disorders: Recent advances and new entities

Patients with sleep-related motor and behavioral disorders present to a variety of subspecialty clinics (neurology, sleep medicine, respiratory medicine, psychiatry). Diagnosing these disorders can be difficult, and sometimes they have a significant impact on quality of life. Alongside a number of common and well-recognized conditions, several new disease entities have been described in recent years that present with abnormal nocturnal motor phenomena (such as ADCY5-associated disease and anti-IgLON5 disease). Our understanding of the neural basis and prognostic significance of other sleep-related disorders has also grown, particularly rapid eye movement sleep behavior disorder. This review (along with a collection of previously unpublished videos) is intended to aid in the recognition and treatment of these patients. The recent change in terminology from nocturnal frontal lobe epilepsy to sleep-related hypermotor epilepsy is also discussed. © 2018 International Parkinson and Movement Disorder Society.

Incorporating epilepsy genetics into clinical practice: a 360°evaluation

We evaluated a new epilepsy genetic diagnostic and counseling service covering a UK population of 3.5 million. We calculated diagnostic yield, estimated clinical impact, and surveyed referring clinicians and families. We costed alternative investigational pathways for neonatal onset epilepsy. Patients with epilepsy of unknown aetiology onset < 2 years; treatment resistant epilepsy; or familial epilepsy were referred for counseling and testing. We developed NGS panels, performing clinical interpretation with a multidisciplinary team. We held an educational workshop for paediatricians and nurses. We sent questionnaires to referring paediatricians and families. We analysed investigation costs for 16 neonatal epilepsy patients. Of 96 patients, a genetic diagnosis was made in 34% of patients with seizure onset < 2 years, and 4% > 2 years, with turnaround time of 21 days. Pathogenic variants were seen in SCN8A, SCN2A, SCN1A, KCNQ2, HNRNPU, GRIN2A, SYNGAP1, STXBP1, STX1B, CDKL5, CHRNA4, PCDH19 and PIGT. Clinician prediction was poor. Clinicians and families rated the service highly. In neonates, the cost of investigations could be reduced from £9362 to £2838 by performing gene panel earlier and the median diagnostic delay of 3.43 years reduced to 21 days. Panel testing for epilepsy has a high yield among children with onset < 2 years, and an appreciable clinical and financial impact. Parallel gene testing supersedes single gene testing in most early onset cases that do not show a clear genotype-phenotype correlation. Clinical interpretation of laboratory results, and in-depth discussion of implications for patients and their families, necessitate multidisciplinary input and skilled genetic counseling.

Screening for epilepsy-related gene variants can lead to effective, personalized treatment plans while reducing costs. UK and Danish scientists, led by Deb Pal, King’s College London, evaluated a new service within the UK that searches for genetic variants in patients that cause epilepsy. The authors assessed the impact of next-generation gene panel tests, as well as the necessary resources to make such a service effective. Genetic testing was most effective in patients with seizure onset under 2 years old (21% diagnosed) and yield even higher in neonatal-onset epilepsy (63% diagnosed). For many patients with pathogenic variants, the diagnoses allowed for recommendations on treatment or enrolment in clinical trials. The researchers found that diagnostic delay and financial burden in neonatal epilepsy could be drastically reduced with gene panel testing. The scheme was highly rated by users and patients alike.

Stress, seizures, and epilepsy: Patient narratives

In epilepsy, individual seizures can be triggered by a variety of external and internal stimuli. One of the most common trigger factors reported by patients is stress. However prevalent, stress-related triggering of episodes seems underappreciated in epilepsy for various reasons, and its misinterpretation often leads to other diagnoses, e.g., psychogenic nonepileptic seizures (PNES) or normal reactions. This article illustrates the significant role of stress as a seizure-provoking factor by referring to nine patient narratives. From this perspective, it appears that there are characteristic patterns of stress triggering, e.g., stress-induced sleep disruption, forms of acute stress, or relaxation after stress. Sometimes seizures are mistaken as symptoms of stress. Patient narratives contain interesting clues relating reports about stress and seizure histories to different epilepsy syndromes as well as nonepileptic episodes in a way that can strongly support the diagnostic process. A narrative approach is particularly valuable in this context. Therefore, accounts of stress triggering in seizures and other episodes should not be neglected, but rather taken seriously, sought and actively explored as a crucial element when taking clinical histories in patients with episodic attacks.

Pediatric Sleep Disorders

PURPOSE OF REVIEW

This article provides an overview of the clinical features, diagnosis, and treatment of insomnia, restless legs syndrome, periodic limb movements of sleep, parasomnias, narcolepsy, and sleep-related breathing disorders among children and adolescents.

RECENT FINDINGS

Pediatric presentations of sleep disorders differ from adult presentations, making diagnosis challenging. Specific clinical syndromes, such as cataplexy in children with narcolepsy type 1, can have an altogether different presentation compared to adult-onset symptoms, contributing to diagnostic delays and potential misdiagnoses. More broadly, research shows strong associations between sleep and daytime cognition, mood, and behavior among children with and without neurologic conditions and thus suggests a need to identify and treat sleep problems to optimize daytime functioning.

SUMMARY

Addressing sleep problems in children with neurologic conditions and neurodevelopmental disorders improves quality of life for patients and their families and, in many cases, reduces neurologic disease burden.