Continuous Spike-waves Research Articles

C.3 Retrospective study of sulthiame in treatment of pediatric epilepsy

Background: This retrospective study assessed the efficacy and tolerability of sulthiame as a treatment in children with epilepsy. In Canada, sulthiame is only available through Health Canada’s Special Access Program. Methods: Patients who received sulthiame at the Montreal Children’s Hospital from April 2012 to March 2023 were included. Patients’ medical charts were reviewed, and clinical data was extracted from neurology clinic notes and electroencephalogram (EEG) reports. Efficacy was assessed by comparing seizure frequency and frequency of EEG epileptiform abnormalities before and after initiating sulthiame, while also noting any reported changes in cognition or behaviour. Results: Sixteen patients were included (10 males, 6 females), all of whom had drug-resistant epilepsy and continuous spike-wave in sleep (CSWS) on EEG. Sulthiame starting dose ranged from 0.74 to 6.75 mg/kg/day. Improvement, either in terms of seizure control, cognition, or reduction in EEG epileptiform abnormalities, was reported in 8/16 children (50%). Two patients (13%) became seizure free, while three more (19%) had reduced seizure frequency. Three other patients (19%) had reported improvements in concentration, learning abilities or behaviour. No serious adverse event was reported. Conclusions: These data indicate that sulthiame is effective and well-tolerated in children with CSWS, regardless of the etiology and type of epilepsy.

Continuous spike-wave of slow sleep in a patient with KCNB1-related epilepsy responsive to highly purified cannabidiol: a case report and comparison with literature

ABSTRACT KCNB1-associated encephalopathy is characterized by intellectual disability (ID), autism spectrum disorder and epilepsy. Specific treatments are still lacking. We describe a 12-year-old boy with severe ID and treatment-resistant seizures due to a pathogenic KCNB1 variant. His EEG showed a CSWS pattern. Aged 11, he started treatment with highly purified cannabidiol (CBD) and has been seizure free for 18 months, with significant EEG and social skills improvements. This suggests CBD may benefit CSWS, likely due to its anti-inflammatory properties. Some preclinical studies also indicate CBDs interact with voltage-gated channels, leading us to speculate its possible role for treating KCNB1 related encephalopathy.

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.

Mowat-Wilson Syndrome; 3 Cases with Characteristic EEG Findings (P3-1.008)

<h3>Objective:</h3> This is a case-based review of clinical manifestations and electroencephalogram findings of Mowat-Wilson Syndrome (MWS) <h3>Background:</h3> MWS is a rare multi system disorder due to ZEB2 gene defects. The main feature of MWS is epilepsy; 75–80% prevalence was noted in prior case series. <h3>Design/Methods:</h3> Children with known diagnoses of MWS were identified in the Pediatric Epilepsy Clinic attached to a tertiary-care pediatric hospital through retrospective chart review. Literature was searched with keywords ‘Mowat-Wilson Syndrome’ and ‘EEG features’ <h3>Results:</h3> Three children with MWS were identified. All cases were heterozygous for ZEB2 gene mutations and had brain imaging and electroencephalograms available for review. <h3>Patient A (11 year-old):</h3> Semiology was generalized and focal (oral automatisms and left-hand flapping). On electroencephalogram there was continuous 2–3 Hz spike-and-wave activity during sleep with left predominance (left frontal at first, but then involving the entire left hemisphere over the years), and intermittent 2.5–3 Hz high-voltage generalized spike-and-wave bursts during wakefulness <h3>Patient B (7 year-old):</h3> Semiology was generalized and focal (right-sided hypotonia and leftwards gaze). On electroencephalogram there were frequent 2–3 Hz poly-spike-and-wave discharges with left frontal-central predominance during sleep, and seizures stemming from right temporal and parieto-occipital areas during status epilepticus <h3>Patient C (4 year-old):</h3> Semiology was generalized. On electroencephalogram there were frequent bi-occipital sharp-and-slow-wave discharges as well as infrequent bursts of high-amplitude generalized 1–2 Hz spike-and-waves <h3>Conclusions:</h3> Electroencephalograms of 2 of 3 patients had continuous spike-waves in sleep (CSWS), even as seizure burden and semiology differed. While there was no CSWS in Patient C, there were sharp-and-slow-wave discharges during wakefulness. It is possible that due to Patient C’s younger age, the EEG has not progressed to develop full CSWS. Indeed, in Patient A, there was a clear progression of EEG abnormalities as the child grew older. This leads these authors to believe that CSWS seems to be distinctly common among Mowat-Wilson. <b>Disclosure:</b> Dr. Shahab has nothing to disclose. Dr. Anilkumar has received publishing royalties from a publication relating to health care.

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

ObjectiveContinuous 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. MethodsN = 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. ResultsThe 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. SignificanceThalamic lesions are present in most CSWS patients with abnormal MRIs, supporting an important role in its genesis.

Koolen-de Vries syndrome associated with continuous spike-wave in sleep

Koolen-de Vries syndrome (KdVS) is a genetic condition caused by 17q21.31 microdeletions or pathogenic variants in KANSL1. Affected patients most commonly exhibit some or all of the following: neonatal hypotonia, developmental impairment, facial dysmorphic features, and congenital malformations. Epilepsy occurs in approximately half, often with phenotypes on the epilepsyaphasia spectrum. We describe six children with KdVS found to have continuous spike-wave in sleep (CSWS) on EEG, four of whom were diagnosed with epileptic encephalopathy with CSWS and two with Landau-Kleffner syndrome. When compared with other children with CSWS on EEG, patients with KdVS may present at slightly later ages and with a longer interval between seizure diagnosis and identification of CSWS. There is no clear best treatment for children with CSWS, but two patients in our cohort were trialed on a variation of the ketogenic diet, and both reported clinical improvement. In one of the patients, the response was dramatic, and CSWS recurred when weaning of the ketogenic diet was attempted. Based on our findings, an EEG capturing a prolonged period of sleep should be arranged in any child with KdVS presenting with developmental regression or plateau, particularly if they have a preceding history of seizures.

Altered closed state inactivation gating in Kv4.2 channels results in developmental and epileptic encephalopathies in human patients.

Kv4.2 subunits, encoded by KCND2, serve as the pore-forming components of voltage-gated, inactivating ISA K+ channels expressed in the brain. ISA channels inactivate without opening in response to subthreshold excitatory input, temporarily increasing neuronal excitability, the back propagation of action potentials, and Ca2+ influx into dendrites, thereby regulating mechanisms of spike timing-dependent synaptic plasticity. As previously described, a de novo variant in Kv4.2, p.Val404Met, is associated with an infant-onset developmental and epileptic encephalopathyin monozygotic twin boys. The p.Val404Met variant enhances inactivation directly from closed states, but dramatically impairs inactivation after channel opening. We now report the identification of a closely related, novel, de novo variant in Kv4.2, p.Val402Leu, in a boy with an early-onset pharmacoresistant epilepsy that evolved to an epileptic aphasia syndrome (Continuous Spike Wave during Sleep Syndrome). Like p.Val404Met, the p.Val402Leu variant increases the rate of inactivation from closed states, but significantly slows inactivation after the pore opens. Although quantitatively the p.Val402Leu mutation alters channel kinetics less dramatically than p.Val404Met, our results strongly support the conclusion that p.Val402Leu and p.Val404Met cause the clinical features seen in the affected individuals and underscore the importance of closed state inactivation in ISA channels in normal brain development and function.

Mild neurological phenotype in a family carrying a novel N-terminal null GRIN2A variant

GRIN2A encodes for the 2A subunit of N-methyl-D-aspartate receptors. Pathogenic variants in GRIN2A have been associated with a wide spectrum of neurodevelopmental disorders ranging from speech disorders and/or self-limiting epilepsy (childhood epilepsy with centrotemporal spikes) to severe and disabling phenotypes (atypical childhood epilepsy with centrotemporal spikes, epileptic encephalopathy with continuous spike-wave during sleep, Landau-Kleffner syndrome and infantile-onset epileptic encephalopathy). Here we describe a family with two affected sisters with atypical childhood epilepsy with centrotemporal spikes and their mildly affected mother carrying a novel N-terminal null variant in GRIN2A gene. These familial cases corroborate previous studies showing that loss-of-function GRIN2A variants are associated with milder phenotypes, possibly due to haploinsufficiency.

HP27: Continuous spike-waves during slow-wave sleep (CSWS): An electroclinical evaluation according to the EEG patterns

To determine a possible association between clinical manifestations and EEG characteristics of CSWS patients. Introduction: CSWS is a rare condition that occurs only in children and adolescents, characterized by a distinctive electroencephalogram (EEG) and heterogeneous clinical manifestations. Aims: To determine a possible association between clinical manifestations and EEG characteristics of CSWS patients. Methods: We reviewed data of 12 pediatric patients who received a sleep EEG showing near-continuous spike-wave (SW) discharge (>50%) on a poorly organized sleep pattern. We defined the CSWS pattern as anterior if the maximum amplitude and/or the start of the SW were frontal, fronto-central or fronto-temporal and as posterior if the maximum amplitude and/or the start of the SW were temporal, temporo-occipital or occipital on the EEG. Results: The study included 12 patients (58% male) with a mean age of 4,6 years. Seven children had an anterior pattern with motor seizures in 3 cases and loss of contact in 4 cases. Five children had a posterior pattern with sensory motor seizures, loss of contact, aphasia in 1 case each and motor seizure in 2 cases. All the children presented cognitive abnormalities. Conclusion: The association between the EEG pattern of CSWS and clinical manifestations is controversial but remains a hypothesis to be awakened.

What is the effect of pharmacological treatment for continuous spike-wave during slow wave sleep syndrome and Landau-Kleffner syndrome? A Cochrane Review summary with commentary.

What is the effect of pharmacological treatment for continuous spike-wave during slow wave sleep syndrome and Landau-Kleffner syndrome? A Cochrane Review summary with commentary.

Role of neuropsychology in identification of CSWS in a school-aged child with a remote neurological insult

Electrical status epilepticus of slow-wave sleep (ESES) is characterized by excessive interictal spike-wave discharges on EEG during sleep and can occur in the absence of overt clinical seizures. Continuous spike-wave during slow wave sleep (CSWS), an epilepsy syndrome associated with ESES, is associated with a plateau/decline in cognitive development and increases in behavioral and emotional dysregulation. Here we present a case in which neuropsychological (NP) evaluation initially ordered based on memory and attention concerns led to the identification of subclinical seizure activity and an evolving epileptic encephalopathy in an 11-year-old child with a history of remote neurological insult. The patient was referred for an initial NP evaluation at age 8 which revealed weaknesses in functions typically mediated by the dominant (usually left) hemisphere juxtaposed with her left hemiparesis. EEG was recommended which showed independent, multifocal spike and sharp wave discharges exacerbated by sleep. Follow-up NP evaluations over the following 26months, during which time aggressive treatment was initiated, coincided with EEG findings of an evolving epileptic encephalopathy in the patient who continued to remain free from clinical seizures. This case highlights the importance of comprehensive epilepsy care and routine involvement of neuropsychology in the management of complex epilepsy patients.

Continuous spike-waves of slow-wave sleep: A case study with 20-year follow-up

Objective . To understand the pathogenesis of continuous spike-waves of slow-wave sleep in autistic spectrum disorders, and how to precisely manage such a challenging complex chronic case. This is the case of PM, a 5 year old right-handed girl from Gujrat India who first presented with dizziness and vomiting while sleeping. Onset of such events started one and a half year ago. She also cried in between and lost consciousness for about 10 minutes’ duration. She suffered a partial seizure and her parents started AED therapy-one year and a half later. She first presented when she was five years and 3 months of age in India. PM is currently a 20-year-old right-handed woman who was followed for 16 years by the same neurologist (PAH), had seizure onset at 1.5 years: afebrile seizures secondarily generalized with automatisms, duration about 5 minutes, recurrent every 2–5 weeks. Initial treatment consisted of Phenytoin 12 mg/kg, then Carbamazepine 30 mg/kg+ (starting dose), Valproate at 18 mg/kg/day with improvement. SGA 2.7 kg at birth, after 7–8 hours labour, her “right leg was bent” at birth in India. Family history was negative for fits or epilepsy. Her early development was “normal”: walked at 12 months, spoke words in Gujarati at 18 months, started English as a second language (ESL) at four years old in Junior kindergarten when she first came to Canada with her family. Since then she had completed high school at age 20 years and planned post-secondary studies at college to be determined by her parents. Her EEGs showed almost continuous high amplitude spike-waves 60% or more in SWS, but only mildly abnormal when awake. Her last clinical seizure occurred a few years ago, still in high school, off all AEDs. The general neurological examination was unremarkable but was rather delayed. Discussion . The relationship between sleep and epilepsy is a challenging issue. In this case the correlation between sleep and possible ASD is unequivocally important. Poor quality in sleep for the pediatric age group often leads to future cognitive and psychosocial issues. These issues must be addressed precisely and handled with parent and psychosocial intervention. An increased level of education and awareness of her condition may help improve the long-term prognosis and improve the quality of life of the patient.

Continuous spike-and-wave activity during slow-wave sleep in patients with rett syndrome

The article presents a description of a clinical case of a child 3 years 8 months old with Rett syndrome caused by the mutation of p.Val485fs in theMECP2gene. According to electroencephalography data at the age of 1 year and 6 months, diffuse continued epileptiform activity in the form of high-amplitude (up to 300 μV) acute – slow wave complexes (continuous spike-waves during slow-wave sleep, CSWS) with an index of 90–100 % was revealed. At the control examination at the age of 2 years and 10 months diffuse epileptiform activity was replaced by multifocal activity with an index of up to 70–80 % at certain epochs, in general, not exceeding 50–60 %. During the entire observation period there were no epileptic seizures. It remains unknown whether the presence of CSWS at such an early age is a predictor of a more severe course of Rett syndrome – in our observation the girl did not acquire walking skills and a delay in psychic and speech development was evident already before the 12 month of life. more research is needed on the frequency of the CSWS phenomenon and its role in the development of clinical features in Rett syndrome.

IL1RAPL1 Gene Deletion in a Female Patient with Developmental Delay and Continuous Spike-Wave during Sleep

AbstractInterleukin-1 receptor accessory protein-like 1 (IL1RAPL1) encodes a protein that is highly expressed in neurons and has been shown to regulate neurite outgrowth as well as synapse formation and synaptic transmission. Clinically, mutations in or deletions of IL1RAPL1 have been associated with a spectrum of neurological dysfunction including autism spectrum disorder and nonsyndromic X-linked developmental delay/intellectual disability of varying severity. Nearly all reported cases are in males; in the few reported cases involving females, the clinical presentation was mild or the deletion was identified in phenotypically normal carriers in accordance with X-linked inheritance. Using genome-wide microarray analysis, we identified a novel de novo 373 kb interstitial deletion of the X chromosome (Xp21.1-p21.2) that includes exons 4 to 6 of the IL1RAPL1 gene in an 8-year-old girl with severe intellectual disability and behavioral disorder with a history of developmental regression. Overnight continuous video electroencephalography revealed electrical status epilepticus in sleep (ESES). This case expands the clinical genetic spectrum of IL1RAPL1-related neurodevelopmental disorders and highlights a new genetic association of ESES.

Identification of a novel GRIN2D variant in a neonate with intractable epileptic encephalopathy-a case report

BackgroundN-methyl-D-aspartate (NMDA) receptors are ligand-gated ion channels that mediate excitatory synaptic transmission in the central nervous system. The functional NMDA receptors are heterotetramers consisting mainly of two GluN1 and two GluN2 subunits. GluN2 is encoded by the GRIN2D gene. A few case series have shown that GRIN2D variants are linked to developmental and epileptic encephalopathy. In this article, we report a novel GRIN2D variant, namely c.2021C > A (p.T674K) in a neonate with intractable epileptic encephalopathy.Case presentationA 12-day-old boy who had stiffness of the lower and upper extremities since birth was transferred from a local hospital to our department. On admission, the patient presented with head tilting backwards, staring, apnea and hypertonia of limbs. Video electroencephalogram showed continuous, generalized or multi-focal spike-wave and spike-and-slow wave discharges and hypsarrhythmia. A treatment regimen composed of phenobarbital, midazolam, levetiracetam and clonazepam was administered, which however led to only partial control of the seizure. Whole-exome sequencing identified c.2021C > A (p.T674K) in GRIN2D in the patient while such a mutation was not detected in the parents. The patient was hospitalized for 1 month and died of sudden cardio-respiratory arrest 2 weeks after discharge.ConclusionsA novel variant of GRIN2D was identified in a neonate with epileptic encephalopathy. Epilepsy associated with this GRIN2D mutation is refractory to conventional anti-epileptic medications.

Wearable EEG Device for Continuous Spike-Wave in Sleep.

Investigators from the Hospital Dona Estefânia, Escola Superior de Tecnologias e Saúde de Lisboa and Centro Hospitalar Psiquiátrico de Lisboa investigated 38 patients with continuous spike-wave of sleep (CSWS) syndrome.

Pharmacological treatment for continuous spike-wave during slow wave sleep syndrome and Landau-Kleffner Syndrome.

Continuous spike-wave during slow wave sleep syndrome (CSWS) and Landau-Kleffner syndrome (LKS) are two epileptic encephalopathies that present with neurocognitive regression, aphasia, and clinical seizures, typically presenting in children around five years of age. The pathophysiology of these conditions is not completely understood. Some studies suggest a common origin for both. No systematic reviews have assessed the efficacy of pharmacological interventions for these conditions. To assess the benefit and adverse effects of pharmacological interventions for the treatment of CSWS and LKS. On 8 September 2020, we searched the Cochrane Register of Studies (CRS Web) and MEDLINE Ovid (1946 to September 04, 2020). We applied no language restrictions. CRS Web includes randomised or quasi-randomised, controlled trials from CENTRAL, PubMed, Embase, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform. Randomised controlled trials, quasi-randomised controlled trials, and cluster-randomised trials comparing antiepileptic drugs alone, or with steroids or intravenous immunoglobulins, or both versus other antiepileptic drugs, or placebo, or no treatment, administered to children with CSWS and LKS. We planned to compare treatments for the two conditions separately. Two review authors independently assessed studies identified by the search strategy for inclusion. The primary outcomes considered in this review were neuropsychological-neurolinguistic functions. Our search strategy yielded 18 references. Two review authors independently assessed all references. We did not find any completed studies to include. We identified one ongoing trial, which was terminated because of lack of enrolment. There was no evidence from trials to support or refute the use of pharmacological treatment for continuous spike-wave during slow wave sleep syndrome or Landau-Kleffner syndrome. Well-designed randomised controlled trials are needed to inform practice.

Exome sequencing in 57 patients with self-limited focal epilepsies of childhood with typical or atypical presentations suggests novel candidate genes.

Self-limited focal epilepsies of childhood (SFEC) are amongst the best defined and most frequent epilepsy syndromes affecting children with usually normal developmental milestones. They include core syndromes such as Rolandic epilepsy or "Benign" epilepsy with Centro-Temporal Spikes and the benign occipital epilepsies, the early onset Panayiotopoulos syndrome and the late-onset Gastaut type. Atypical forms exist for all of them. Atypical Rolandic epilepsies are conceptualized as belonging to a continuum reaching from the "benign" RE to the severe end of the Landau-Kleffner (LKS) and Continuous Spike-Waves during Sleep syndromes (CSWS). GRIN2A has been shown to cause the epilepsy-aphasia continuum that includes some patients with atypical Rolandic epilepsy with frequent speech disorders, LKS and CSWS. In the present study, we searched novel genes causing SFEC with typical or atypical presentations. Exome sequencing was performed in 57 trios. Patients presented with typical or atypical SFEC, negative for GRIN2A pathogenic variant. We found rare candidate variants in 20 patients. Thirteen had occurred de novo and were mostly associated to atypical Rolandic Epilepsy. Two of them could be considered as disease related: a null variant in GRIN2B and a missense variant in CAMK2A. Others were considered good candidates, including a substitution affecting a splice site in CACNG2 and missense variants in genes encoding enzymes involved in chromatin remodeling. Our results further illustrate the fact that atypical SFEC are more likely to have Mendelian inheritance than typical SFEC.

Electroclinical spectrum of childhood epilepsy secondary to neonatal hypoglycemic brain injury in a low resource setting: A 10-year experience

PurposeNeonatal hypoglycemic brain injury (NHBI) is being increasingly recognized as an important cause of drug resistant childhood epilepsy in low resource settings. We report the electro-clinical spectrum of children with epilepsy secondary to NHBI. MethodsThis was a retrospective study of children enrolled in the Epilepsy Clinic from January 2009 to August 2019. Data of children who had developed epilepsy after documented symptomatic neonatal hypoglycemia was collected. Details of clinical profile, seizure types, neurodevelopmental co-morbidities, EEG, neuroimaging findings and seizure outcomes were noted. ResultsOne hundred and seventy children were enrolled. The mean age at seizure onset was 10.3 months (SD 0.5 months). The seizures types were epileptic spasms (76.5%), focal with visual auras (11.2%), bilateral tonic clonic (7.1%), myoclonic (3.5%) and atonic seizures (1.8%). The EEG findings included classical hypsarrhythmia (49.4%), hypsarrhythmia variant (27.1%), focal occipital or temporo-occipital spike wave discharges (10.6%), multifocal discharges (4.7%), diffuse slow spike and wave with bursts of fast rhythms (2.4%), continuous spike waves during sleep (1.2%) and normal EEG (4.7%). MRI showed gliosis with or without encephalomalacia in the occipital lobe with or without parietal lobe in 96.5% of the patients. Co-morbidities included global developmental delay (91.2%), cerebral palsy (48.7%), vision impairment (48.2%), microcephaly (38.2%), hearing impairment (19.4%), and behavioural problems (16.5%). Drug resistant childhood epilepsy was seen in 116 (68.2%) patients. ConclusionsOur study highlights the varied electroclinical and radiological spectrum and the adverse epilepsy and neurodevelopmental outcomes associated with NHBI.

Interictal spike quantification in continuous spike–wave of sleep (CSWS): Clinical usefulness of a wearable EEG device

IntroductionContinuous spike–wave of sleep (CSWS) syndrome is one of the most common epileptic encephalopathies of childhood. Because the associated cognitive/behavioral disturbances relate more to the amount of spike activity than of seizures, methods of spike quantification gained relevance in diagnosis and monitoring treatment. The conventional methodology for quantification of spike index (SI) relies on repeated full 10–20 long-term ambulatory electroencephalography (aEEG), which is both expensive and poorly tolerated. ObjectiveThe objectives of this study were to demonstrate the clinical value of repeated SI assessments in CSWS and to build and validate a wearable device allowing inexpensive and well-tolerated, repeated quantifications. MethodsA group of N = 38 patients with CSWS were submitted to repeated SI quantifications based on aEEG, as seen fit by the medical clinical assistant. Responses to therapy with corticosteroids (N = 10), sulthiame (N = 7), and the ketogenic diet (N = 3) were monitored. We used a conventional method based on a semiautomatic template match spike search. The individual variability in time spans of days (N = 4) or months (N = 10) was assessed and used to determine the meaningful neurophysiological responses to the diverse therapies.A wearable device capable of recording 2 bipolar EEG channels for 24 h was used to simplify SI quantification. ResultsCorticosteroids produced the most powerful SI reduction, but a large individual variability in both amount and time of onset of clinical response with some patients exhibiting recurrence shortly after therapy. A more frequent sampling of SI would provide a more accurate follow-up, with clinical benefit.The comparison of the SI obtained from standard 10–20 electrodes and 2 bipolar EEG channel subsets in aEEG or between the 10–20 and simultaneous wearable recordings, demonstrated that the new method provides an accurate SI quantification. ConclusionsA wearable EEG device with 2 bipolar channels simplifies the process of obtaining repeated SI quantification allowing a more accurate follow-up of spike activity in the clinical setting.