Spike Wave Index Calculation in Electrical Status Epilepticus of Sleep: First Step Towards Standardized Practice

Abstract number : 3.182
Submission category : 4. Clinical Epilepsy / 4A. Classification and Syndromes
Year : 2023
Submission ID : 1222
Source : www.aesnet.org
Presentation date : 12/4/2023 12:00:00 AM
Published date :

Authors :
Presenting Author: Nancy McNamara, MD – University of Michigan, Michigan Medicine

Daniel Arndt, MD – Corewell Health; Fiona Baumer, MD – Stanford; Danilo Bernardo, MD – UCSF; Sonal Bhatia, MBBS MD – Medical University of South Carolina; Catherine Chu, MD – Harvard; William Gaillard, MD – Children's National; David Hsu, MD PhD – University of Wisconsin Madison; Cemal Karakas, MD – University of Louisville; Sarah Kelley, MD – Johns Hopkins; Dalila Lewis, MD – Medical University of South Carolina; Tobias Loddenkemper, MD – Harvard; Saleem Malik, MD – Cook Children's Hospital; Adam Ostendorf, MD – Nationwide Children’s Hospital The Ohio State University; Shital Patel, MD – Duke; Spriha Pavuluri, MD – Children's Omaha; Elia Pestana-Knight, MD – Cleveland Clinic; Donald Phillips, MD – Children's Hospital Orange County; Lekha Rao, MD – UCLA; Rani Singh, MD – Atrium Health Levine Children’s Hospital; Wake Forest University School of Medicine; Carey Wilson, MD – University of Utah; Tesfaye Zelleke, MD – Children's National Medical Center; Anthony Fine, MD – Mayo

Electrical status epilepticus of sleep (ESES) is an EEG pattern of continuous spike and wave discharges activated in NREM sleep. This EEG finding is typically associated with a developmental and epileptic encephalopathy (DEE) of varying severity, ranging from autistic features to severe developmental regression, often in language and/or motor domains. Most children will have electroclinical seizures of varying semiology and burden, while some only have subclinical EEG findings in sleep. In 2022, the ILAE Nosology Task Force recommended grouping the previously named epilepsy syndromes of CSWS (continuous spike and wave in slow wave sleep) and LKS (Landau-Kleffner syndrome) under the heading of DEE-SWAS (DEE with spike wave activation in sleep). EEG criteria set forth was 50% or greater spike activation of the NREM EEG. These are rare epilepsy syndromes affecting 0.5-0.6% of children (age 2-12 y, peak 3-5 y) with epilepsy but with devastating consequences [3,4].

The ESES Special Interest Group under the Pediatric Epilepsy Research Consortium is a multicenter collaborative effort between US pediatric epilepsy centers. The most recent classification does not account for the existing problem of significant practice variability in EEG diagnostic criteria in ESES. Our group sought to elucidate the methods used by pediatric epileptologists for quantification of the spike index in ESES.

1 Eksioglu Y, Tas E, Takeoka M, et al. Clinical presentation and acute treatment of electrical status epilepticus in sleep and sleep potentiated spikes [abstract]. 2009. Neurology. 72; A434.

2 Morikawa T, Seino M, Watanabe Y, et al. Clinical relevance of continuous spike-waves during slow wave sleep. In: Manelis S, Bental E, Loeber JN, Dreifuss FE, eds.1998. Advances in Epileptology. New York, NY: Raven Press; 359 –363. 

An IRB exempt anonymized RedCap survey was sent to members of the Pediatric Epilepsy Research Consortium (PERC) and their colleagues. Participants were asked to describe the methods they utilized to quantify the spike wave index (SWI), whether there was a standardized method or protocol at their epilepsy center, and if they used any other assessments when evaluating the sleep EEG. Future efforts will compare the different SWI methods reported.

Results: A total of 69 surveys were returned. Of those respondents, 37.6% (26/69) used the percentage of one seconds bins containing at least one spike wave over the first five minute epoch of sleep. Nineteen respondents (27.5%) used the percentage of one second bins containing at least one spike wave over the first 100 second epoch of sleep. Eleven of sixty-nine (15.9%) respondents had no standardized method. The remaining 13 respondents (18.8%) had varied ways of calculating the SWI (Graph 1).

This small study highlights the significant variability in quantifying SWI and ultimately diagnosing ESES and DEE-SWAS. Efforts to simplify the name of this disorder are helpful, but fail to capture the complexities and heterogeneity which exist in this diagnosis. These challenges further extend to management of children with this disorder. Consensus is needed regarding the best method for EEG assessment of the SWI in children with DEE-SWAS.

Funding: None

Clinical Epilepsy