Clinical spectrum and treatment outcome of 95 children with continuous spikes and waves during sleep (CSWS)

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.

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.

Unmet needs in epileptic encephalopathy with spike-and-wave activation in sleep: A systematic review

INTRODUCTION

Developmental and/or epileptic encephalopathy with spike-and-wave activation in sleep (D/EE-SWAS), also referred to as electrical status epilepticus during sleep (ESES) or epileptic encephalopathy with continuous spike-and-wave during sleep (CSWS or EE-CSWS), is a spectrum of rare childhood epileptic encephalopathies that can lead to long-term cognitive impairment. Despite the importance of early diagnosis and intervention for D/EE-SWAS, there is a paucity of well-controlled clinical trial data to inform treatment, and no approved treatments are available. To assess correlations between diagnosis, treatment, and outcomes in D/EE-SWAS, we carried out a systematic review of the literature.

METHODS

In August 2020, we conducted comprehensive database searches using search terms including "electrical status epilepticus," "ESES," "CSWS," and "Landau-Kleffner syndrome." Two or more independent reviewers screened titles, abstracts, and full-text articles for those that met the following criteria: prospective studies (randomized controlled trials [RCTs] or open-label trials), retrospective studies (drug evaluations or observational studies/chart reviews), and case series with ≥ 10 participants. Both interventional and non-interventional studies were included (i.e., drug intervention was not an inclusion criterion). Articles published before 2012, review articles, animal studies, and studies of surgical or dietary interventions were excluded. Standardized data extraction templates were used to capture data on study design, patient characteristics, interventions, and outcomes from each of the selected publications. Study quality was assessed using the Cochrane Risk of Bias Tool for RCTs and the Newcastle-Ottawa Scale (NOS) or the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for retrospective, observational studies.

RESULTS

A total of 34 studies were included for full data extraction, most of which were uncontrolled and observational. Interpretation of study outcomes was limited by small study populations, variability in inclusion criteria, and inconsistency in methods of assessment and reporting of outcomes, which resulted in large heterogeneity in patients and their presenting symptoms. Despite these limitations, some patterns could be discerned. Several studies found that longer duration of ESES and younger age at onset were correlated with more severe language and cognitive deficits. In addition, several studies reported an association between improvement in cognitive outcomes and reduction in electroencephalogram (EEG) abnormalities and/or seizure frequency. In the 16 prospective or retrospective studies that evaluated drug treatments (e.g., antiseizure medications, corticosteroids, and high-dose diazepam), there was some improvement in EEG, seizure, and/or cognitive outcomes, although the specific outcomes and rates of improvement reported varied from study to study.

CONCLUSION

Long-term cognitive deficits remain common in D/EE-SWAS, and data gaps exist in the literature that preclude an evidence-based approach to managing this complex epilepsy indication. Early intervention with more effective medications is needed to optimize long-term outcomes. Sufficiently powered, randomized, double-blind, controlled trials with standardized methods and predefined primary and secondary outcomes are needed.

Disease Course and Response to Immunotherapy in Children With Childhood Disintegrative Disorder: A Retrospective Case Series

Childhood disintegrative disorder is a poorly understood neurobehavioral disorder of early childhood characterized by acute to subacute profound regression in previously developed language, social behavior, and adaptive functions. The etiology of childhood disintegrative disorder remains unknown and treatment is focused on symptomatic management. Interest in neuroinflammatory mechanisms has grown with the increased recognition of autoimmune brain diseases and similarities between the presenting symptoms of childhood disintegrative disorder and pediatric autoimmune encephalitis. Importantly, a diagnosis of pediatric autoimmune encephalitis requires evidence of inflammation on paraclinical testing, which is absent in childhood disintegrative disorder. Here we report 5 children with childhood disintegrative disorder who were initially diagnosed with possible autoimmune encephalitis and treated with immunotherapy. Two children had provocative improvements, whereas 3 did not change significantly on immunotherapy. Additionally, a sixth patient with childhood disintegrative disorder evaluated in our Autoimmune Brain Disease Clinic showed spontaneous improvement and is included to highlight the variable natural history of childhood disintegrative disorder that may mimic treatment responsiveness.

How the Spreading and Intensity of Interictal Epileptic Activity Are Associated with Visuo-Spatial Skills in Children with Self-Limited Focal Epilepsy with Centro-Temporal Spikes

This paper investigates brain-behaviour associations between interictal epileptic discharges and cognitive performance in a population of children with self-limited focal epilepsy with centro-temporal spikes (SeLECTS). Sixteen patients with SeLECTS underwent an extensive neuropsychological assessment, including verbal short-term and episodic memory, non-verbal short-term memory, attentional abilities and executive function. Two quantitative EEG indices were analysed, i.e., the Spike Wave Index (SWI) and the Spike Wave Frequency (SWF), and one qualitative EEG index, i.e., the EEG score, was used to evaluate the spreading of focal SW to other parts of the brain. We investigated associations between EEG indices and neuropsychological performance with non-parametric Spearman correlation analyses, including correction for multiple comparisons. The results showed a significant negative correlation between (i) the awake EEG score and the Block Tapping Test, a visuo-spatial short-term memory task, and (ii) the sleep SWI and the Tower of London, a visuo-spatial planning task (pcorr < 0.05). These findings suggest that, in addition to the usual quantitative EEG indices, the EEG analysis should include the qualitative EEG score evaluating the spreading of focal SW to other parts of the brain and that neuropsychological assessment should include visuo-spatial skills.

The prospective study of 54 children with electrical status epilepticus during sleep: How to simplify the electroencephalogram diagnosis and guide the treatment

OBJECTIVE

To simplify the electroencephalogram (EEG) diagnosis and guide the treatment of electrical status epilepticus during sleep (ESES).

METHODS

We recruited 54 children with ESES from December 2019 to December 2020 and compared various spike-wave index (SWI) calculation methods. Time-frequency analysis assessed the correlation between high-frequency oscillations energy and the SWI. We divided 42 children into responder and non-responder treatment groups based on the observations made during a 12-month follow-up period and evaluate different treatment and the independent risk factors of refractory ESES.

RESULTS

The SWI of 5 min before the second sleep cycle of non-rapid eye movement (NREM; long method II) and that of all NREM sleep (total method) were not significantly different (p = .06). The average energy of γ (r = .288, p = .002) and ripple (r = .203, p = .04) oscillations were correlated with the SWI. Multivariable logistic regression analysis showed that encephalomalacia was an independent risk factor for refractory ESES (OR: 10.48, 95% CI: 1.62-67.63). The clinical seizure improvement rates of anti-seizure medications (ASMs), ASMs with benzodiazepines, and ASMs with benzodiazepines and steroids after 12 months were 9.3%, 42.8%, and 53.8%, EEG improvement rate were 5.5%, 30.9% and 37%, respectively. The intelligence of the children in the responder treatment group has improved during the 1-year follow-up.

SIGNIFICANCE

These findings demonstrate EEG and clinical features of ESES and may provide basis for simplifying diagnosis and guiding the treatment of children with ESES.

Is sleep captured during a standard daytime EEG sufficient to diagnose Electrical Status Epilepticus in Sleep

Electrical Status epilepticus of sleep (SES) is an EEG pattern where there is significant activation of epileptiform activity in NREM sleep. A spike wave index (SWI) of > 80-85% is often labelled as typical SES. We aimed to explore if sleep during a standard daytime-EEG, as compared an overnight-EEG, was adequate to diagnose ESES. Ten children with daytime and overnight studies suggestive of SES were audited. SWI and Spike Wave Density (SWD) were calculated for 5-minute epochs of wake in the daytime and overnight study, as well daytime-EEG sleep and first and last NREM cycle in the overnight-EEG. SWI in daytime NREM was not significantly different from SWI in the first sleep cycle of the overnight study. SWI in the last sleep cycle was significantly lower than the first sleep cycle in the overnight-EEG. SWD was significantly higher in the first sleep cycle in the overnight-EEG than the daytime sleep and the last NREM cycle. SES may be diagnosed in NREM sleep from a daytime-EEG study. Larger studies are needed to explore the significance of the disparity between SWI and SWD in the first and last NREM cycles in the overnight study.

Developmental and/or epileptic encephalopathy with spike-and-wave activation in sleep in Saudi Arabia: Electroclinical, etiologic, genetic, and outcome multicenter study

OBJECTIVES

To investigate the clinical features of developmental and/or epileptic encephalopathy with spike-and-wave activation in sleep (D/EE-SWAS), its electrographic characteristics, and etiology and to compare the effects of different treatment strategies on the outcomes using a Saudi Arabian database.

METHODS

This multicenter study included children with D/EE-SWAS who were evaluated between 2010 and 2020 at 11 tertiary centers. Data were collected on their baseline clinical features, etiologies, and treatment modalities. Seizure reduction, spike-wave index, and cognitive state were examined as potential therapeutic outcomes.

RESULTS

Ninety-one children were diagnosed with D/EE-SWAS, with a median age of 7 years (IQR: 3-5) and an almost equal sex distribution. The average age at which epilepsy was diagnosed was 3 years (IQR: 5-2). A genetic/metabolic etiology was found in 35.1% of the patients, and a structural etiology was found in 27.4%. Children with underlying genetic/metabolic diseases exhibited an earlier seizure onset (P = 0.001) than children with other etiologies. Benzodiazepines (76.6%) were the most common treatment, followed by steroids (51.9%). Sodium valproate (75%) was the most frequently used antiseizure medication, followed by levetiracetam (64.9%). Children with a later seizure onset were more likely to have better clinical responses (P = 0.046), EEG responses (P = 0.012), and cognitive outcomes (P = 0.006) than children with an earlier onset. Moreover, better seizure response and electrographic response were seen in patients with bilateral interictal discharges on the EEG than otherwise. Children had a higher likelihood of both clinical and electrographic improvement with combination therapy of benzodiazepines (P = 0.001) and steroids (P = 0.001) than with other therapies.

SIGNIFICANCE

This study shows a higher prevalence of genetic/metabolic causes and suggests the superior efficacy of combination therapy with steroids and benzodiazepines in D/EE-SWAS. Prospective studies that strictly assess the treatment protocols and outcomes are needed.

High incidence of early thalamic lesions in the Continuous Spike-Wave related with slow Sleep (CSWS)

OBJECTIVE

Continuous Spike-Wave during slow Sleep (CSWS) syndrome associates a clinically important neurocognitive regression with strong activation of non-REM sleep spikes. Its mechanisms remain unknown, but a contribution of rare perinatal thalamic injuries has been highlighted. We determine the incidence of such lesions in a cohort of CSWS patients.

METHODS

N = 65 patients with CSWS and a control group (N = 51) were studied. Spikes were quantified in long-term ambulatory EEGs, brain Magnetic Ressonance Imaging (MRI) structural lesions were assessed and thalamic volumetry was performed. A neurocognitive scale was used to assess dysfunction.

RESULTS

The most common etiologies in the control patients were not represented in the CSWS group. Structural lesions were detected in a minority of CSWS patients (25/53) but included a thalamic injury in the large majority (24/25). This ratio was 4/40 in controls. Lesions belonged to one of five types: 1. Circumscribed to the thalamus (N = 11); 2. Extending beyond the thalamus (N = 3); 3. Hypothalamic-Hamartomas (N = 4); 4. Periventricular-Leukomalacia (N = 4); 5. Hypoplasia-Polymicrogyria (N = 1). Most lesions were lateralized to one hemisphere, which in all cases corresponded to the lateralization of the CSWS.

SIGNIFICANCE

Thalamic lesions are present in most CSWS patients with abnormal MRIs, supporting an important role in its genesis.

Developmental and epileptic encephalopathies - therapeutic consequences of genetic testing

Developmental and epileptic encephalopathies comprise a heterogeneous group of monogenic neurodevelopmental disorders characterized by early-onset seizures, marked epileptic activity and abnormal neurocognitive development. The identification of an increasing number of underlying genetic alterations and their pathophysiological roles in cellular signaling drives the way toward novel precision therapies. The implementation of novel treatments that target the underlying mechanisms gives hope for disease modification that will improve not only the seizure burden but also the neurodevelopmental outcome of affected children. So far, beneficial effects are mostly reported in individual trials and small numbers of patients. There is a need for international collaborative studies to define the natural history and relevant outcome measures and to test novel pharmacological approaches.

Clinical Spectrum and Treatment Outcomes of Patients with Developmental and/or Epileptic Encephalopathy with Spike-and-Wave Activation in Sleep

Purpose: Developmental and/or epileptic encephalopathy with spike-and-wave activation in sleep (D/EE-SWAS) is a spectrum of conditions characterized by various phenotypes of cognitive, linguistic, and behavioral regression associated with spike-and-wave activation in sleep. We aimed to investigate the phenotypic spectrum and treatment outcomes of pediatric patients with D/EE-SWAS.Methods: We retrospectively analyzed the medical records of pediatric patients diagnosed with D/EE-SWAS and treated at Severance Children’s Hospital from 2006 to 2022. We extracted information from their medical records on electroencephalography before and after treatment, types of treatment, seizure frequency, and developmental profiles. The primary outcome was reduction of the spike-wave index on electroencephalography after treatment.Results: Twenty-one patients with a median age of 5.3 years (interquartile range, 4.1 to 6.6) at diagnosis were included. Ten patients had delayed development. The patients received various anti-seizure medications. Fourteen received long-term, high-dose steroid therapy, 10 were placed on a ketogenic diet, four received intravenous steroid pulse therapy, and one each was treated with intravenous immunoglobulin and cannabidiol. The most effective treatments were steroid therapy and a ketogenic diet, which were also effective in reducing seizures and improving cognition. Side effects during treatment were transient and treatable.Conclusion: We described the clinical spectrum of pediatric patients with D/EE-SWAS. Steroid therapy and a ketogenic diet can be considered effective therapeutic options for patients with D/EE SWAS.

Neurobehavioral deterioration associated with sleep-augmented epileptiform abnormalities: A steroid responsive state in children

OBJECTIVE

Retrospective case record analysis of children with Neurobehavioral Deterioration associated with Sleep-augmented Epileptiform abnormalities (NDSE).

METHODS

Hospital records of children with NDSE (July, 2015 through December, 2016) were analyzed. Children were categorized as: Encephalopathy with electrical status epilepticus in sleep (ESES) if sleep EEG Spike-wave-Index (SWI) was ≥50% and sleep-induced epileptiform activity (SIEA)-related cognitive dysfunction if SWI ≥25% but <50%. Demography, neurobehavior profile (IQ/SQ and behavior using validated psychometric tools), etiology, investigations and treatment details were documented. Outcome assessment was based on three-month follow-up records.

RESULTS

Eighteen children with NDSE {12 boys; median age at diagnosis: 7.5 years (IQR: 6-10 years); SIEA (7); ESES (11)} were included. Etiology was structural (23%) and presumed genetic (77%). All children received intravenous-methylprednisolone pulse followed by oral steroids for eight weeks. Electroencephalography of children with SIEA was partly organized with median SWI of 40% (IQR 35, 42), with anterior-predominant epileptiform abnormalities and less apparent secondary synchronization. Children with ESES had a disorganized EEG background with median SWI of 80% (IQR 66, 95). Both SIEA and ESES groups had a similar neurobehavior profile. Behavior scores improved in 6/8 children with ESES and 5/7 in SIEA post steroids. In both the groups, median SWI improved (to <5% in SIEA, 45% in ESES). Mild improvement in IQ/SQ was also noted {SIEA [Median (IQR): 3 (1.6, 4.3)]; ESES [Median (IQR): 3.8 (2.8, 7)]}.

CONCLUSION

The study supports the fact that SWI >50% in the nap EEG is not mandatory for the diagnosis of ESES, thus it should not be a constraint for steroid treatment.

Complementing the phenotypical spectrum of TUBA1A tubulinopathy and its role in early-onset epilepsies

TUBA1A tubulinopathy is a rare neurodevelopmental disorder associated with brain malformations as well as early-onset and intractable epilepsy. As pathomechanisms and genotype-phenotype correlations are not completely understood, we aimed to provide further insights into the phenotypic and genetic spectrum. We here present a multicenter case series of ten unrelated individuals from four European countries using systematic MRI re-evaluation, protein structure analysis, and prediction score modeling. In two cases, pregnancy was terminated due to brain malformations. Amongst the eight living individuals, the phenotypic range showed various severity. Global developmental delay and severe motor impairment with tetraparesis was present in 63% and 50% of the subjects, respectively. Epilepsy was observed in 75% of the cases, which showed infantile onset in 83% and a refractory course in 50%. One individual presented a novel TUBA1A-associated electroclinical phenotype with evolvement from early myoclonic encephalopathy to continuous spike-and-wave during sleep. Neuroradiological features comprised a heterogeneous spectrum of cortical and extracortical malformations including rare findings such as cobblestone lissencephaly and subcortical band heterotopia. Two individuals developed hydrocephalus with subsequent posterior infarction. We report four novel and five previously published TUBA1A missense variants whose resulting amino acid substitutions likely affect longitudinal, lateral, and motor protein interactions as well as GTP binding. Assessment of pathogenic and benign variant distributions in synopsis with prediction scores revealed sections of variant enrichment and intolerance to missense variation. We here extend the clinical, neuroradiological, and genetic spectrum of TUBA1A tubulinopathy and provide insights into residue-specific pathomechanisms and genotype-phenotype correlations.

Clonic seizures, continuous spikes-and-waves during slow sleep, choreoathetosis and response to sulthiame in a child with FRRS1L encephalopathy

BACKGROUND

Ferric chelate reductase 1 like (FRRS1L) encephalopathy is a rare cause of developmental and epileptic encephalopathy. Only a few cases have been reported thus far and seizures tend to be drug refractory. We report an additional case to highlight the good seizure response to sulthiame.

CASE REPORT

A boy from non-consanguineous parents presented with history of 'abnormal movements' from 7 months of age. At one year of age, video electroencephalogram (EEG) monitoring demonstrated the 'abnormal movements' to be clonic seizures. Valproate, lamotrigine and clobazam combination were only partially effective at reducing the seizures. Repeat EEG at 1 year 8 months old revealed a continuous spikes-and-waves during slow sleep (CSWS) pattern, prompting a trial of sulthiame. After 2 weeks of sulthiame, seizures ceased completely. The clonic seizures recurred at age 4 years when sulthiame supply was interrupted, but the seizures promptly remitted following sulthiame's resumption. Subtle choreiform movements appeared from age one year and later became more prominent. Whole exome sequencing (WES) identified a homozygous novel variant (nonsense) in the FRRS1L gene (NM_014334.3: c.670C>T:p.Gln224*). He has been seizure free since 4 years of age but remained profoundly delayed.

CONCLUSION

Sulthiame may have a role in the early treatment of seizures in children with refractory epilepsy due to FRRS1L mutation.