Encephalopathy related to status epilepticus during slow sleep (ESES). Pathophysiological insights and nosological considerations

The influence of wakefulness fluctuations on brain networks involved in centrotemporal spike occurrence

OBJECTIVE

Drowsiness has been implicated in the modulation of centro-temporal spikes (CTS) in Self-limited epilepsy with Centro-Temporal Spikes (SeLECTS). Here, we explore this relationship and whether fluctuations in wakefulness influence the brain networks involved in CTS generation.

METHODS

Functional MRI (fMRI) and electroencephalography (EEG) was simultaneously acquired in 25 SeLECTS. A multispectral EEG index quantified drowsiness ('EWI': EEG Wakefulness Index). EEG (Pearson Correlation, Cross Correlation, Trend Estimation, Granger Causality) and fMRI (PPI: psychophysiological interactions) analytic approaches were adopted to explore respectively: (a) the relationship between EWI and changes in CTS frequency and (b) the functional connectivity of the networks involved in CTS generation and wakefulness oscillations. EEG analyses were repeated on a sample of routine EEG from the same patient's cohort.

RESULTS

No correlation was found between EWI fluctuations and CTS density during the EEG-fMRI recordings, while they showed an anticorrelated trend when drowsiness was followed by proper sleep in routine EEG traces. According to PPI findings, EWI fluctuations modulate the connectivity between the brain networks engaged by CTS and the left frontal operculum.

CONCLUSIONS

While CTS frequency per se seems unrelated to drowsiness, wakefulness oscillations modulate the connectivity between CTS generators and key regions of the language circuitry, a cognitive function often impaired in SeLECTS.

SIGNIFICANCE

This work advances our understanding of (a) interaction between CTS occurrence and vigilance fluctuations and (b) possible mechanisms responsible for language disruption in SeLECTS.

Clinical analysis of developmental and/or epileptic encephalopathy with spike-and-wave activation in sleep: A single tertiary care center experience in China

PURPOSE

To analyze the electroclinical features of patients with developmental and/or epileptic encephalopathy with spike-and-wave activation in sleep (DEE/EE-SWAS) and study the efficacy of different therapies on seizure control, electroencephalogram (EEG) improvements of electrical status epilepticus during sleep (ESES), and cognition outcomes.

METHODS

Patients with DEE/EE-SWAS who underwent at least one follow-up EEG 3 months after therapy were retrospectively enrolled. The demographic and clinical characteristics of the patients were analyzed. Variables that influenced the outcomes were evaluated using logistic regression models.

RESULTS

In total, 87 patients (47 males) were included. The median age at ESES recognition was 81.0 months (IQR 64.0, 96.0). Forty-six patients were diagnosed with self-limited focal epilepsies (SeLFEs) before ESES recognition, 24 with developmental and epileptic encephalopathies with spike-and-wave activation in sleep (DEE-SWAS), and 17 with other epilepsies. Steroids, benzodiazepines, and antiseizure medications (ASMs) were the initial treatment options for ESES. Patients with structural etiologies or slow EEG backgrounds at the time of ESES recognition were less likely to respond to treatment than other patients. However, only children with slow EEG backgrounds had lower odds of response in logistic regression models. Children with clinical or EEG response showed improvements in cognition.

CONCLUSION

Steroids, benzodiazepines, and ASMs are effective treatments for patients with DEE/EE-SWAS. Children with structural etiologies or slow EEG backgrounds at the time of ESES recognition may have a poor long-term prognosis. The efficacy of seizure reduction and EEG improvement is associated with cognitive improvement.

Developmental epileptic encephalopathy in DLG4-related synaptopathy

OBJECTIVE

The postsynaptic density protein of excitatory neurons PSD-95 is encoded by discs large MAGUK scaffold protein 4 (DLG4), de novo pathogenic variants of which lead to DLG4-related synaptopathy. The major clinical features are developmental delay, intellectual disability (ID), hypotonia, sleep disturbances, movement disorders, and epilepsy. Even though epilepsy is present in 50% of the individuals, it has not been investigated in detail. We describe here the phenotypic spectrum of epilepsy and associated comorbidities in patients with DLG4-related synaptopathy.

METHODS

We included 35 individuals with a DLG4 variant and epilepsy as part of a multicenter study. The DLG4 variants were detected by the referring laboratories. The degree of ID, hypotonia, developmental delay, and motor disturbances were evaluated by the referring clinician. Data on awake and sleep electroencephalography (EEG) and/or video-polygraphy and brain magnetic resonance imaging were collected. Antiseizure medication response was retrospectively assessed by the referring clinician.

RESULTS

A large variety of seizure types was reported, although focal seizures were the most common. Encephalopathy related to status epilepticus during slow-wave sleep (ESES)/developmental epileptic encephalopathy with spike-wave activation during sleep (DEE-SWAS) was diagnosed in >25% of the individuals. All but one individual presented with neurodevelopmental delay. Regression in verbal and/or motor domains was observed in all individuals who suffered from ESES/DEE-SWAS, as well as some who did not. We could not identify a clear genotype-phenotype relationship even between individuals with the same DLG4 variants.

SIGNIFICANCE

Our study shows that a subgroup of individuals with DLG4-related synaptopathy have DEE, and approximately one fourth of them have ESES/DEE-SWAS. Our study confirms DEE as part of the DLG4-related phenotypic spectrum. Occurrence of ESES/DEE-SWAS in DLG4-related synaptopathy requires proper investigation with sleep EEG.

Expanding the clinical and genetic landscape of (developmental) epileptic encephalopathy with spike-and-wave activation in sleep: results from studies of a Turkish cohort

The terms developmental epileptic encephalopathy with spike-and-wave activation in sleep (DEE-SWAS) and epileptic encephalopathy with spike-and-wave activation in sleep (EE-SWAS) designate a spectrum of conditions that are typified by different combinations of motor, cognitive, language, and behavioral regression linked to robust spike-and-wave activity during sleep. In this study, we aimed at describing the clinical and molecular findings in "(developmental) epileptic encephalopathy with spike-and-wave activation in sleep" (D)EE-SWAS) patients as well as at contributing to the genetic etiologic spectrum of (D)EE-SWAS. Single nucleotide polymorphism (SNP) array and whole-exome sequencing (WES) techniques were used to determine the underlying genetic etiologies. Of the 24 patients included in the study, 8 (33%) were female and 16 (67%) were male. The median age at onset of the first seizure was 4 years and the median age at diagnosis of (D)EE-SWAS was 5 years. Of the 24 cases included in the study, 13 were compatible with the clinical diagnosis of DEE-SWAS and 11 were compatible with the clinical diagnosis of EE-SWAS. Abnormal perinatal history was present in four cases (17%), and two cases (8%) had a family history of epilepsy. Approximately two-thirds (63%) of all patients had abnormalities detected on brain computerized tomography/magnetic resonance (CT/MR) imaging. After SNP array and WES analysis, the genetic etiology was revealed in 7 out of 24 (29%) cases. Three of the variants detected were novel (SLC12A5, DLG4, SLC9A6). This study revealed for the first time that Smith-Magenis syndrome, SCN8A-related DEE type 13 and SLC12A5 gene variation are involved in the genetic etiology of (D)EE-SWAS. (D)EE-SWAS is a genetically diverse disorder with underlying copy number variations and single-gene abnormalities. In the current investigation, rare novel variations in genes known to be related to (D)EE-SWAS and not previously reported genes to be related to (D)EE-SWAS were discovered, adding to the molecular genetic spectrum. Molecular etiology enables the patient and family to receive thorough and accurate genetic counseling as well as a personalized medicine approach.

Continuous Spike-Waves during Slow Sleep Today: An Update

In the context of childhood epilepsy, the concept of continuous spike-waves during slow sleep (CSWS) includes several childhood-onset heterogeneous conditions that share electroencephalograms (EEGs) characterized by a high frequency of paroxysmal abnormalities during sleep, which have negative effects on the cognitive development and behavior of the child. These negative effects may have the characteristics of a clear regression or of a slowdown in development. Seizures are very often present, but not constantly. The above makes it clear why CSWS have been included in epileptic encephalopathies, in which, by definition, frequent EEG paroxysmal abnormalities have an unfavorable impact on cognitive functions, including socio-communicative skills, causing autistic features, even regardless of the presence of clinically overt seizures. Although several decades have passed since the original descriptions of the electroclinical condition of CSWS, there are still many areas that are little-known and deserve to be further studied, including the EEG diagnostic criteria, the most effective electrophysiological parameter for monitoring the role of the thalamus in CSWS pathogenesis, its long-term evolution, the nosographic location of Landau-Kleffner syndrome, standardized neuropsychological and behavioral assessments, and pharmacological and non-pharmacological therapies.

Sleep and Epilepsy

The relationship between sleep and epilepsy is both intimate and bidirectional. The molecular mechanisms which control circadian rhythm and the sleep/wake cycle are dysregulated in epileptogenic tissue and are themselves effected by molecular pathways for epilepsy. Sleep affects the frequency of interictal epileptiform discharges and recent research has raised new questions regarding the impact of discharges on sleep function and cognition. Epileptiform discharges themselves affect sleep architecture and increase the risk of sleep disorders. Several sleep-related epilepsy syndromes have undergone changes in their classification which highlights their intimate relationship to sleep and novel screening tools have been developed to help clinicians better differentiate epileptic seizures from sleep-related paroxysmal events. Improving sleep and addressing sleep disorders has been associated with improved seizure control and increased well-being in people with epilepsy. These interactions are discussed in detail in this review.

The Relationship Between Sleep, Epilepsy, and Development: a Review

PURPOSE OF REVIEW

To review the relationship between sleep, neurodevelopment, and epilepsy and potential underlying physiological mechanisms.

RECENT FINDINGS

Recent studies have advanced our understanding of the role of sleep in early brain development and epilepsy. Epileptogenesis has been proposed to occur when there is a failure of normal adaptive processes of synaptic and homeostatic plasticity. This sleep-dependent transformation may explain the cognitive impairment seen in epilepsy, especially when occurring early in life. The glymphatic system, a recently discovered waste clearance system of the central nervous system, has been described as a potential mechanism underlying the relationship between sleep and seizures and may account for the common association between sleep deprivation and increased seizure risk. Epilepsy and associated sleep disturbances can critically affect brain development and neurocognition. Here we highlight recent findings on this topic and emphasize the importance of screening for sleep concerns in people with epilepsy.

What are the considerations when initiating treatment for epilepsy in children?

INTRODUCTION

There is a very wide spectrum of epilepsies and developmental and epileptic encephalopathies that affect children, from self-limited forms, not necessarily requiring treatment, to severe drug-resistant ones.

AREAS COVERED

In this perspective, the authors discuss the main factors to consider before drug prescription in children, considering the most recent clinical research, including age, seizure type, epilepsy syndrome, etiology, efficacy and safety profile, comorbidities, gender, available formulations, costs and drug coverage, and regulatory issues. The literature search was conducted through a PubMed search on antiseizure medications for patients aged 0-18, with respect to each of the aforementioned factors, and by checking the reference lists of relevant papers.

EXPERT OPINION

The most expanding field of research and innovation for clinical practice is precision medicine, which addresses the holistic treatment of genetic epilepsies and developmental and epileptic encephalopathies. It achieves this by addressing their detrimental effects on synapses, neurotransmission, and cellular signaling pathways with the double aim to treat seizures and to rescue neurodevelopmental trajectories, but also the issue of adverse events and drug resistance through pharmacogenomics.