Epilepticus During Slow-wave Sleep Research Articles

Efficacy and Safety of Pulse Intravenous Methylprednisolone in Pediatric Epileptic Encephalopathies: Timing and Networks Consideration.

Background: Epileptic encephalopathies (EE) are characterized by severe drug-resistant seizures, early onset, and unfavorable developmental outcomes. This article discusses the use of intravenous methylprednisolone (IVMP) pulse therapy in pediatric patients with EE to evaluate its efficacy and tolerability. Methods: This is a retrospective study from 2020 to 2023. Inclusion criteria were ≤18 years at the time of IVMP pulse therapy and at least 6 months of follow-up. Efficacy and outcome, defined as seizure reduction > 50% (responder rate), were evaluated at 6 and 9 months of therapy, and 6 months after therapy suspension; quality of life (QoL) was also assessed. Variables predicting positive post-IVMP outcomes were identified using statistical analysis. Results: The study included 21 patients, with a responder rate of 85.7% at 6 and 9 months of therapy, and 80.9% at 6 months after therapy suspension. Variables significantly predicting favorable outcome were etiology (p = 0.0475) and epilepsy type (p = 0.0475), with the best outcome achieved in patients with genetic epilepsy and those with encephalopathy related to electrical status epilepticus during slow-wave sleep (ESES). All patients evidenced improvements in QoL at the last follow-up, with no relevant adverse events reported. Conclusions: Our study confirmed the efficacy and high tolerability of IVMP pulse therapy in pediatric patients with EE. Genetic epilepsy and ESES were positive predictors of a favorable clinical outcome. QOL, EEG tracing, and postural-motor development showed an improving trend as well. IVMP pulse therapy should be considered earlier in patients with EE.

Electro-clinical features and long-term outcomes in guanidinoacetate methyltransferase (GAMT) deficiency

ObjectiveTo evaluate clinical characteristics and long-term outcomes in patients with guanidinoacetate methyltransferase (GAMT) deficiency with a special emphasis on seizures and electroencephalography (EEG) findings. MethodsWe retrospectively analyzed the clinical and molecular characteristics, seizure types, EEG findings, neuroimaging features, clinical severity scores, and treatment outcomes in six patients diagnosed with GAMT deficiency. ResultsMedian age at presentation and diagnosis were 11.5 months (8–12 months) and 63 months (18 months −11 years), respectively. Median duration of follow-up was 14 years. Global developmental delay (6/6) and seizures (5/6) were the most common symptoms. Four patients presented with febrile seizures. The age at seizure-onset ranged between 8 months and 4 years. Most common seizure types were generalized tonic seizures (n = 4) and motor seizures resulting in drop attacks (n = 3). Slow background activity (n = 5) and generalized irregular sharp and slow waves (n = 3) were the most common EEG findings. Burst-suppression and electrical status epilepticus during slow-wave sleep (ESES) pattern was present in one patient. Three of six patients had drug-resistant epilepsy. Post-treatment clinical severity scores showed improvement regarding movement disorders and epilepsy. All patients were seizure-free in the follow-up. ConclusionsEpilepsy is one of the main symptoms in GAMT deficiency with various seizure types and non-specific EEG findings. Early diagnosis and initiation of treatment are crucial for better seizure and cognitive outcomes. This long-term follow up study highlights to include cerebral creatine deficiency syndromes in the differential diagnosis of patients with global developmental delay and epilepsy and describes the course under treatment.

The Prevalence and Risk Factors of Electrical Status Epilepticus During Slow-Wave Sleep in Self-Limited Epilepsy With Centrotemporal Spikes.

Objective. To investigate the prevalence and risk factors for electrical status epilepticus during slow-wave sleep (ESES) in patients with self-limited epilepsy with centrotemporal spikes (SeLECTS). Methods. The clinical and follow-up data of children with SeLECTS were collected between 2017 and 2021. Patients were divided into typical ESES, atypical ESES, and non-ESES groups according to spike-wave indices (SWI). Clinical and electroencephalography characteristics were retrospectively analyzed. Logistic regression was used to identify risk factors for ESES. Results. A total of 95 patients with SeLECTS were enrolled. Seven patients (7.4%) developed typical ESES, 30 (31.6%) developed atypical ESES, 25 (26.3%) developed ESES at the first visit, and 12 (12.6%) developed ESES during treatment and follow-up. Multivariate logistic regression analysis showed that the risk factors for SeLECTS combined with ESES were Rolandic double or multiple spikes (OR = 8.626, 95% CI: 2.644-28.147, P < .001) and Rolandic slow waves (OR = 53.550, 95% CI: 6.339-452.368, P < .001). There were no significant differences in seizure characteristics, electroencephalogram (EEG) findings, or cognitive impairment between the atypical and typical ESES groups. Conclusion. More than one-third of the SeLECTS patients combined with ESES. Both atypical and typical ESES scores can affect cognitive function. On electroencephalography, interictal Rolandic double/multiple spikes and slow-wave abnormalities may indicate SeLECTS with ESES.

Early electrophysiological predictors of progression of hydrocephalus in children with epilepsy

Hydrocephalus is a severe disease in children of all age groups. Failure to treat hydrocephalus in a timely manner can lead to progressive neurological deficits and death. Instead, early diagnosis and treatment of progressive hydrocephalus can completely recover the child. The term «early diagnosis» of hydrocephalus is the most difficult task for a pediatric neurologist. There are no pathognomonic clinical signs of this disease. Detection of electrophysiological signs of hydrocephalus progression in the early stages of the disease could significantly affect on treatment outcomes. The aim of our work is to establish early electrophysiological predictors of the progression of hydrocephalus in children with epilepsy. Materials and methods. 28 children with epilepsy were examined at the Transcarpathian Regional Children’s Hospital and the Medical Center «Diamed» in Uzhhorod from 2018 to 2022. All children were examined prospectively using video-EEG monitoring with sleep fixation, magnetic resonance imaging (MRI), multispiral computer tomography (MSCT). Results. The electrical status epilepticus during slow-wave sleep (ESES) was registered in 35 % of examined patients (8 children). The average duration from detection of the electrical status of sleep to the establishment of shunt system in the brain is 37 days (from 15 to 60 days). The ESES disappeared in 6 children during the first month after the implantation of the shunt system in the brain, in 2 children during the next 3 and 6 months of observation. We have developed our own algorithm for examining children with hydrocephalus and epilepsy up to 1 year and older than 1 year. Conclusion. An intense increase of epileptiform activity and appearance of electrical status of slow-wave sleep may be one of the predictors of the progression and decompensation of hydrocephalus and requires dynamic control. Further randomized trials are needed to assess the significance of these changes. The developed algorithm will increase the effectiveness of the use of additional examination methods for early detection of the progression of hydrocephalus in children with epilepsy.

Is epileptiform activity related to developmental language disorder? Findings from the HelSLI study

ObjectiveTo study if interictal epileptiform discharges (IEDs) are associated with language performance or pre-/perinatal factors in children with developmental language disorder (DLD). MethodsWe recorded routine EEG in wake and sleep in 205 children aged 2.9–7.1 years with DLD, without neurologic diseases or intellectual disability. We examined the language performance of the children and collected data on pre-/perinatal factors. ResultsInterictal epileptiform discharges were not associated with lower language performance. Children with so-called “rolandic”, i.e. centrotemporoparietal, IEDs had better language skills, but age explained this association. Most pre-/perinatal factors evaluated did not increase the risk of rolandic IEDs, except for maternal smoking (OR 4.4, 95% CI 1.4–14). We did not find electrical status epilepticus during slow-wave sleep (ESES)/spike-and-wave activation in sleep (SWAS) in any children. ConclusionsInterictal epileptiform discharges are not associated with lower language performance, and ESES/SWAS is not common in children with DLD. SignificanceRoutine EEGs do not bring additional information about language performance in children with DLD who do not have any neurologic diseases, seizures, intellectual disability, or regression of language development.

Electrical status epilepticus during slow-wave sleep (ESES): Current perspectives

ABSTRACTElectrical status epilepticus during slow-wave sleep (ESES) is an epilepsy syndrome with sleep-induced epileptic discharges and acquired impairment of cognition or behavior. Since the disease’s original description in 1971, no clear consensus has emerged on diagnostic criteria or optimal treatment. The treatment of ESES can be challenging, often including numerous antiepileptic drugs, immunomodulatory agents, and even surgical interventions. There is little evidence to guide treatment because only retrospective studies and case reports on the efficacy of treatment of ESES are present in literature. In this paper, we aim to analyze the etiopathogenesis of ESES in the new genetic era and to evaluate the treatment modalities in accordance with the genetic data and electroclinic spectrum of ESES.

Benefits of ketogenic diet in a pediatric patient with Ehlers-Danlos syndrome and STXBP1-related epileptic encephalopathy

Purpose/Aim Ehlers-Danlos syndrome (EDS) is a hereditary connective tissue disease. Epilepsy is not a common neurological finding in EDS. Here we report a pediatric patient with EDS comorbid with STXBP1 related epileptic encephalopathy as ‘electrical status epilepticus during slow-wave sleep (ESES)’ and whose refractory epileptic seizures were controlled with ketogenic diet. Case report A 6-year-old girl who had EDS presented with refractory seizures and worsening cognitive functions. Her sleep electroencephalography (EEG) revealed electrical status epilepticus during slow-wave sleep (ESES). The epileptic encephalopathy panel revealed a de novo c.560C > T (p.pro187Leu) heterozygous mutation in the STXPB1 gene. Ketogenic diet treatment was started for her refractory seizures and seizures stopped in the third month of the 3:1 classical ketogenic diet. Conclusion Our case is remarkable due to the coexistence of EDS and epileptic encephalopathy as well as ESES findings in STXBP1-associated epileptic encephalopathy and is therefore presented. Ketogenic diet would be beneficial on the management of refractory seizures in STXBP1-related epileptic encephalopathy and ESES.

Clinical Forms and GRIN2A Genotype of Severe End of Epileptic-Aphasia Spectrum Disorder.

Objective: This study aims to analyze the electroclinical characteristics and gene test results of children on the severe end of the epilepsy aphasia spectrum (EAS) and also the correlation of EAS-related GRIN2A genes to explore the genotype-phenotype relationships, as well as potential pathogenic mechanism of EAS.Methods: A retrospective study was conducted on the participants diagnosed with Landau-Kleffner syndrome (LKS), epileptic encephalopathy with continuous spike-and-wave during sleep (CSWS), and atypical benign partial epilepsy (ABPE) at the Children's Hospital of Chongqing Medical University from January 2013 to June 2019. Whole-exome sequencing was performed in six patients, and epileptic panel was carried out in two. In addition, we reviewed all the published literatures reporting EAS patients with pathogenic variants until June 2019 and conducted Gene Ontology (GO) analysis, as well as protein-protein interaction (PPI) network.Results: The mean age at seizure onset was 55.4 ± 27.0 months. The baseline severity of the spike-wave index (SWI) was not significantly correlated with intellectual disability (ID) level. Two pathogenic de novo GRIN2A null variants were identified in patients with ABPE who had less severe ID, despite the electrical status epilepticus during slow-wave sleep (ESES). By literature reviewing, 18 GRIN2A missense mutations and 11 GRIN2A truncating mutations which lead to N-methyl-d-aspartate receptors' loss of function has been reported. Of these mutations, 9 (31.0%) are situated in amino (N)-terminal domain, 6 (20.7%) in linger-binding domain S1, and 10 (34.5%) in linger-binding domain S2. EAS-related genes were enriched in the biological process of chemical synaptic transmission and vocalization (FDR, <0.01). The hub protein in PPI network is GluN2A, which might affect language function via foxp2-srpx2/uPAR signal network.Conclusion: Our data suggested that when children suspected with benign epilepsy of children with centrotemporal spikes (BECTs) have early-onset age, changed seizure semiology, and deterioration of behavior/cognition/motor function, neurologists should be alert of the appearance of ESES. The neuropsychological deterioration in children with EAS might not only be completely affected by electric discharge severity but also genetic etiology. Our finding also enforced the current genotype-phenotype relationship theory about EAS. For EAS children, GRIN2A-FOXP2-SRPX2/uPAR signal network might contribute to the mechanism of their language deficit.

Electrical status epilepticus during sleep in patients with congenital Zika virus syndrome: An unprecedented clinical finding

BackgroundBrazil experienced a disproportionately higher rate of microcephaly cases in November 2015 with evidence of a causal link with Zika virus (ZIKV) infections during pregnancy. Epilepsy is a major neurological feature seen as part of congenital Zika virus syndrome (CZVS). Different seizure types and electroencephalographic (EEG) abnormalities have been described in association with this syndrome. However, clinical and neurophysiological features of epilepsy seen in children with CZVS are not fully understood. MethodsWe evaluated children with CZVS showing an EEG pattern of electrical status epilepticus during slow-wave sleep (ESES). Information on gender, age of onset of seizures, head circumference at birth, gross motor function at the time of diagnosis, of clinical and EEG aspects of seizures, EEG features and response to drug treatment was assessed. ResultsOur case series included four patients. They were diagnosed with epilepsy between one month to 18 months of age and showed an ESES pattern at the age of three. They presented with a wide range of epileptic symptoms, but all experienced tonic seizures. Multiple drug treatment was the management approach for three patients; however, they showed poor response to treatment with conventional drugs used in the treatment of ESES. ConclusionsChildren with CZVS may develop an EEG pattern of ESES. Clinicians and neurologists should be aware of this neurological presentation to improve the management of these patients.

Epilepsy in Christianson syndrome: Two cases of Lennox-Gastaut syndrome and a review of literature.

Christianson syndrome (CS) is an X-linked intellectual disorder caused by mutations in the SLC9A6 gene. Clinical features of CS include an inability to speak, truncal ataxia, postnatal microcephaly, hyperkinesis, and epilepsy. Almost all patients with CS develop drug-resistant epilepsy—its most serious complication. We report two cases of CS with drug-resistant epilpesy associated with the Lennox–Gastaut syndrome (LGS). One patient experienced generalized tonic seizures since 9 months of age with cognitive regression, which evolved to include atonic seizures at the age of 7 years. Electroencephalography (EEG) showed generalized slow spike–wave complexes and generalized paroxysmal fast activity. Seizures remained drug-resistant despite multiple anti-seizure drugs. The second patient experienced generalized tonic seizures since the age of 17 months and arrested development. EEG showed generalized slow spike–wave complexes, with frequent atonic seizures since the age of 6 years. Electrical status epilepticus during slow-wave sleep (ESES) developed at the age of 7 years. Our cases illustrate that CS may cause LGS in addition to other developmental and epileptic encephalopathies of the neonatal and infantile period. We suggest that generalized tonic or tonic–clonic seizures and generalized slow spike–wave complexes in interictal EEG be included as potential electroclinical features of epilepsy in CS.

EFFICACY AND SAFETY OF LEVETIRACETAM IN CHILDREN WITH ELECTRICAL STATUS EPILEPTICUS DURING SLOW-WAVE SLEEP (ESES)

Electrical status epilepticus during slow-wave sleep (ESES) is an EEG pattern of continuous (85-100%) diffuse epileptiform activity in the sleep EEG. The morphology of the epileptiform complexes is identical to benign epileptiform discharges of childhood (BEDC). Epilepsy with ESES (or “Penelope Syndrome”) is a form of age-dependent epileptic encephalopathies with the phenomenon of continuous spike-waves during slow wave sleep. This group of epilepsies also includes Pseudo-Lennox syndrome, Landau-Kleffner syndrome, autistic epileptiform regression and some others. In most cases, the ESES pattern correlates with the severity of cognitive deficit in this population of epileptic children. The aim of this study was to evaluate the efficacy and safety of levetiracetam in children with the ESES pattern in the EEG. Materials and Methods. During the period of 2010-2016, 34 epileptic children with ESES patterns in the EEG (14 boys and 20 girls) treated with levetiracetam (33 in combined and 1 in monotherapy) were studied. Results. Twenty eight of the patients with ESES patterns in the sleep EEG were diagnosed with the ESES form of epilepsy. Among them, 7 idiopathic, 13 symptomatic, and 8 “symptomatic” cases of ESES (the latter resulted from “double pathology” of idiopathic + hypoxic-ischemic factors and these children had cerebral palsy). Among other ESES patients, 3 cases were of Pseudo-Lennox syndrome, 2 cases of Landau-Kleffner syndrome and one girl with autistic epileptiform regression. All 28 children received levetiracetam at therapeutic doses of 20-80 mg/kg/daily. Levetiracetam was highly effective in 67.6% of patients (n=23); of those, 2 children showed full clinical and electroencephalographic remission before reaching puberty, 9 children had clinical remission and 12 children had a significant decrease in seizures and epileptiform discharges. A low efficacy of levetiracetam was seen in 20.6% (n=7) of patients. Disease aggravation (seizures and epileptiform discharges) was found in 11.8% (n=4) of patients. Other negative effects were observed in only 4 (11.8%) children (3 cases of agitation and sleep disturbance and one case of allergic rash). In conclusion, levetiracetam is a highly effective medication (67.6% of cases) in combined antiepileptic therapy in children with ESES. However, the risk of exacerbation was as high as 11.8%. The most effective combinations of levetiracetam were those with valproates and ethosuximide.

Epilepsy with electrical status epilepticus during slow-wave sleep with a focus on electroencephalographic criteria

The authors present a detailed literature review, devoted to epilepsy with electrical status epilepticus during slow-wave sleep (ESES), as well as own data. The issues of classification, etiology, ESES diagnostic criteria, aproaches to therapy and prognosis are discussed in the article. Authors pay particular attention to the description of electroencephalographic abnormalities in patients with ESES including changes in electroencephalogram (EEG) during seizures and in the intetictal period (first of all during sleep). EEG during sleep is crucial in case of ESES, it is necessary for diagnosis. 20 % of the patients have no epileptic seizures; the diagnosis is based on the EEG results and neuropsychological testing. Continuous spike-and- wave epileptiform activity on EEG during slow-wave sleep is a compulsory diagnostic criterion for ESES. This activity defines the clinical spectrum of cognitive and behavioral discorders in patients with this disease.

Diagnosis of Electrical Status Epilepticus During Slow-Wave Sleep With 100 Seconds of Sleep.

Strategies for diagnosing electrical status epilepticus during slow-wave sleep (ESES) vary among interpreting neurologists. Our aim was to evaluate if the spike-wave index (SWI) for the first 100 seconds of sleep is reflective of the SWI when compared with a conventional method. We reviewed EEGs from 2005 to 2011 that were considered diagnostic of ESES based on unspecified methods. The SWI for the first nonrapid eye movement sleep cycle (long method) was calculated by two neurophysiologists. Two different neurophysiologists calculated SWI for the first 100 seconds of sleep (short method). For the purposes of this study, ESES was defined as an SWI of >85%. The two SWI scores were compared. Fourteen EEGs were reviewed. Despite being considered by the initial interpreter as diagnostic of ESES, only 4 of the studies had an SWI of >85% based on each of the methods. For a diagnosis of ESES, the sensitivity of the short method is 80% and the specificity is 89%. Wilcoxon signed rank test was used to compare the long and short methods. A P value of 0.70 indicates no significant difference between the methods. Additionally, the Spearman correlation coefficient is 0.553 (P = 0.04), indicating moderate correlation between the methods. The SWI for the first 100 seconds of nonrapid eye movement sleep is predictive of the SWI for the entire first sleep cycle with a good sensitivity and specificity in our cohort. This suggests an alternative method for diagnosing ESES, which is comparable to analysis of a full night of sleep.

Continuous spike‐waves during slow‐wave sleep in a mouse model of focal cortical dysplasia

To examine if mice with focal cortical dysplasia (FCD) develop spontaneous epileptic seizures and, if so, determine the key electroencephalography (EEG) features. Unilateral single freeze lesions to the S1 region (SFLS1R) were made in postnatal day 0-1 pups to induce a neocortical microgyrus in the right cortical hemisphere. Continuous 24-h recordings with intracranial EEG electrodes and behavioral tests were performed in adult SFLS1R and sham-control mice to assess neurologic status. A high percentage of adult SFLS1R animals (89%, 40/45) exhibited at least one or more spontaneous nonconvulsive seizure events over the course of 24 h. Of these animals, 60% (27/45) presented with a chronic seizure state that was persistent throughout the recording session, consisting of bursts of rhythmic high-amplitude spike-wave activities and primarily occurring during periods of slow-wave sleep. In comparison, none of the control, age-matched, mice (0/12) developed seizures. The epileptic discharge pattern closely resembled a pattern of continuous spike-waves during slow-wave sleep (CSWS) of the human syndrome described as an electrical status epilepticus during slow-wave sleep (ESES). Key findings in the SFLS1R model indicated that the observed CSWS (1) were more prevalent in female (18/23) versus male (9/22, p < 0.05), (2) were strongest in the right S1 region although generalized to other brain regions, (3) were associated with significant cognitive and behavioral deficits, (4) were temporarily alleviated by ethosuximide treatment or optogenetic activation of cortical γ-aminobutyric acid (GABA)ergic neurons, and (5) theta and alpha band rhythms may play a key role in the generalization of spike-wave activities. This is the first report of an in vivo animal FCD model that induces chronic spontaneous electrographic brain seizures. Further characterization of the abnormal oscillations in this mouse model may lead to a better understanding of the mechanisms of CSWS/ESES.

ID 361 – Remission of ESES after functional hemispherotomy is associated with significant language development

To study the effect of functional hemispherotomy on electrical status epilepticus during slow wave sleep (ESES) and language development. The source-population comprised prospectively collected data from patients with a history of at least 2 years after functional hemispherotomy. Study inclusion criteria were ascertained diagnosis of ESES prior to surgery and complete developmental follow-up data. A control group without ESES was drawn from the source population. Language Quotients (LQ) prior to surgery and at last follow-up were calculated. Hypotheses were: (1) Children with ESES have lower preoperative LQs than children without ESES; (2) Remission of ESES after surgery is associated with significant ‘catch up’ of the LQs. Nonparametric Wilcoxon and Chi-square tests were applied. 11 cases (five female) and 21 controls (eleven female) were included. Prior to surgery, children with ESES had significantly lower LQs compared with their controls (p = 0.015). The median follow-up after surgery was 6.0 years (±2.2; range 2–9 years). ESES remitted immediately after surgery in 90.9% of the patients. A significant increase in LQ was noticed in these children (p = 0.038). The results were independent of the side of surgery. Functional hemispherotomy may have beneficial effects on ESES and further language development.

A novel mutation in the endosomal Na+/H+ exchanger NHE6 (SLC9A6) causes Christianson syndrome with electrical status epilepticus during slow-wave sleep (ESES)

Mutations in the solute carrier family 9, subfamily A member 6 (SLC9A6) gene, encoding the endosomal Na+/H+ exchanger 6 (NHE6) are associated with Christianson syndrome, a syndromic form of X-linked intellectual disability characterized by microcephaly, severe global developmental delay, autistic behavior, early onset seizures and ataxia. In a 7-year-old boy with characteristic clinical and neuroimaging features of Christianson syndrome and epileptic encephalopathy with continuous spikes and waves during sleep, we identified a novel splice site mutation (IVS10-1G>A) in SLC9A6. These findings expand the clinical spectrum of the syndrome and indicate NHE6 dysfunction as a new cause of electrical status epilepticus during slow-wave sleep (ESES).

Adaptive neuro-fuzzy inference system for classification of background EEG signals from ESES patients and controls.

Background electroencephalography (EEG), recorded with scalp electrodes, in children with electrical status epilepticus during slow-wave sleep (ESES) syndrome and control subjects has been analyzed. We considered 10 ESES patients, all right-handed and aged 3–9 years. The 10 control individuals had the same characteristics of the ESES ones but presented a normal EEG. Recordings were undertaken in the awake and relaxed states with their eyes open. The complexity of background EEG was evaluated using the permutation entropy (PE) and sample entropy (SampEn) in combination with the ANOVA test. It can be seen that the entropy measures of EEG are significantly different between the ESES patients and normal control subjects. Then, a classification framework based on entropy measures and adaptive neuro-fuzzy inference system (ANFIS) classifier is proposed to distinguish ESES and normal EEG signals. The results are promising and a classification accuracy of about 89% is achieved.

Epilepsy with Continuous Spike-Waves during Slow Sleep: When and How Should We Treat?

Epilepsy with continuous spike-waves during slow sleep (CSWS),which is one of the hallmarks of electrical status epilepticus during slow wave sleep (ESES), is a functional disorder with the following features: severe paroxysmal EEG disturbance; seizures that may be severe but self-limited; behavioral deterioration, with or without premorbid developmental disturbances; no demonstrable brain pathology sufficient to explain the behavioral deterioration; and stabilization or improvement of behavior once the epileptiform EEG abnormalities resolve [1]. Much serious in CSWS are cognitive and behavioral disturbances. In CSWS, paroxysmal activity permanently affects the frontal lobes and higher cognitive functions. At highest risk for permanent sequelae are those with the earliest and longest exposure to the active phase of CSWS. When and how should CSWS be treated?

CSWS‐related autistic regression versus autistic regression without CSWS

Continuous spike-waves during slow-wave sleep (CSWS) and Landau-Kleffner syndrome (LKS) are two clinical epileptic syndromes that are associated with the electroencephalography (EEG) pattern of electrical status epilepticus during slow wave sleep (ESES). Autistic regression occurs in approximately 30% of children with autism and is associated with an epileptiform EEG in approximately 20%. The behavioral phenotypes of CSWS, LKS, and autistic regression overlap. However, the differences in age of regression, degree and type of regression, and frequency of epilepsy and EEG abnormalities suggest that these are distinct phenotypes. CSWS with autistic regression is rare, as is autistic regression associated with ESES. The pathophysiology and as such the treatment implications for children with CSWS and autistic regression are distinct from those with autistic regression without CSWS.

Cognition and Paroxysmal EEG Activities: From a Single Spike to Electrical Status Epilepticus during Sleep

Epileptic EEG paroxysms can interfere with cognitive processes producing transitory effects, such as those related to a single spike, as well as long-lasting effects, such as in electrical status epilepticus during slow-wave sleep (ESES). Focal spike-related disruption of cortical functions can produce transitory cognitive impairment, with neuroanatomical specificity between the site of the epileptic focus and the impaired cognitive tasks. ESES represents a model of the long-lasting effects of continuous spike-wave activity on higher cortical functions. The duration of ESES and the localization of interictal foci seem to play a major role in influencing the degree and type of cognitive dysfunction, suggesting that the ESES clinical picture results from a localized disruption of EEG activity caused by focal epileptic activity during sleep. Recently, Giulio Tononi's group reported that a local increase of slow-wave activity (SWA) during sleep after learning is associated with improved performance of the learned task after sleep (Huber et al., Nature 2004;430:78-81). On the basis of these findings, we can speculate that prolonged focal epileptic activity during sleep (as occurring in ESES) interferes with local SWA at the site of the epileptic focus, impairing the neural processes and, possibly, the local plastic changes associated with learning and other cognitive functions.