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PubMed This is a summary of 14 peer-reviewed journal articles Updated
Pediatrics

The Spectrum of Risk: Understanding ESES and CSWS

At a Glance

While SeLECTS is usually mild, it can progress to more severe conditions like ESES or CSWS. The primary warning signs are sudden cognitive declines—such as language loss, academic struggles, or severe behavioral changes—rather than an increase in physical seizures.

For most families, SeLECTS remains a “self-limited” condition that follows a predictable, gentle path. However, doctors view SeLECTS as being on a spectrum [1]. On one end is the classic, manageable version; on the other end are more intensive conditions called ESES (Electrical Status Epilepticus during Sleep) or CSWS (Continuous Spike-and-Wave during Sleep) [2].

The Transition: From SeLECTS to ESES

The transition from typical SeLECTS to the more severe end of the spectrum is not usually marked by more seizures. In fact, a child might have very few physical seizures while their condition is progressing [1].

Instead, the warning signs are neurocognitive. This means you should look for a sudden or unexpected change in your child’s ability to think, learn, or behave [3][1].

  • Warning Sign 1: Language Loss: A child may suddenly struggle to find words, understand instructions, or lose vocabulary they previously mastered [4].
  • Warning Sign 2: Academic Drop: A sudden, sharp decline in school performance or grades [5].
  • Warning Sign 3: Severe Behavior Changes: New, intense impulsivity, aggression, or a loss of social skills that were previously stable [4][3].

Measuring the “Spike Burden” (SWI)

To monitor where a child sits on this spectrum, doctors use a measurement called the Spike-Wave Index (SWI) [6].

  • The SWI is a percentage that tells the doctor how much of your child’s sleep is being “interrupted” by electrical spikes [7].
  • For example, an SWI of 85% means that for 85% of the time your child is in NREM sleep, their brain is firing off spikes instead of resting and consolidating memory [8][9].
  • While there is no “magic number” that automatically means a child has ESES, a high SWI (often over 50–85%) combined with cognitive decline is usually what prompts a doctor to change the treatment plan [7][10].

Why Monitoring Matters

Because the risks of ESES are related to learning and development, doctors often order repeat sleep EEGs if they suspect a child is moving along the spectrum [11][12].

As mentioned in the treatment section, it is also important to know that certain common anti-seizure medications (such as oxcarbazepine) can occasionally make the “sleep spikes” worse in some children, potentially pushing them further along the spectrum [13]. If your child’s behavior or learning worsens after starting a new medication, it is vital to inform your neurologist immediately [13].

The Goal of Treatment

If a child does move into the ESES/CSWS end of the spectrum, the goal shifts. Instead of just stopping physical seizures, the treatment objective becomes “cleaning up” the EEG [14]. Doctors may use different types of treatments—such as high-dose steroids or specific bedside medications—to lower the SWI and allow the child’s brain to return to its normal learning and development path [14][13].

Common questions in this guide

What is the Spike-Wave Index (SWI)?
The Spike-Wave Index is a percentage that shows how much of a child's sleep is interrupted by abnormal electrical spikes. A high SWI, usually over 50 to 85 percent, may indicate a shift toward more severe epilepsy conditions like ESES.
What are the warning signs of ESES or CSWS?
The main warning signs are neurocognitive changes rather than an increase in physical seizures. Parents should watch for sudden language loss, severe academic decline, or new intense behavioral issues like impulsivity or aggression.
Can epilepsy medications make sleep spikes worse?
Yes, certain common anti-seizure medications, such as oxcarbazepine, can occasionally worsen electrical sleep spikes in some children. If your child’s behavior or learning declines after starting a new medication, contact your neurologist immediately.
What is the goal of treating ESES?
If a child develops ESES, the main treatment goal shifts from just stopping physical seizures to reducing the electrical spikes on the EEG. Doctors may use treatments like high-dose steroids to calm the brain's electrical activity so normal learning and development can resume.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.What is my child's current Spike-Wave Index (SWI), and how does it compare to their last EEG?
  2. 2.Are you seeing any 'atypical' EEG markers, like double spikes or slow waves, that might suggest a shift toward ESES?
  3. 3.If we see cognitive regression, what are our options for 'resetting' the sleep spikes (e.g., corticosteroids or benzodiazepines)?
  4. 4.Are any of my child's current medications at risk for making the sleep spikes worse?
  5. 5.How frequently should we be doing repeat sleep EEGs to monitor this spectrum?

Questions For You

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References

References (14)
  1. 1

    The Clinical Spectrum of Benign Epilepsy with Centro-Temporal Spikes: a Challenge in Categorization and Predictability.

    Lee YJ, Hwang SK, Kwon S

    Journal of epilepsy research 2017; (7(1)):1-6 doi:10.14581/jer.17001.

    PMID: 28775948
  2. 2

    Developmental and epileptic encephalopathy with spike-wave activation in sleep: From the 'functional ablation' model to a neurodevelopmental network perspective.

    Andreoli L, Bova SM, Veggiotti P

    Developmental medicine and child neurology 2025; (67(10)):1250-1256 doi:10.1111/dmcn.16361.

    PMID: 40356337
  3. 3

    Early identification of epileptic encephalopathy with continuous spikes-and-waves during sleep: A case-control study.

    Desprairies C, Dozières-Puyravel B, Ilea A, et al.

    European journal of paediatric neurology : EJPN : official journal of the European Paediatric Neurology Society 2018; (22(5)):837-844 doi:10.1016/j.ejpn.2018.04.009.

    PMID: 29739701
  4. 4

    Exploring the Correlations Between Language Impairments, Central Auditory Processing Disorder, Neuropsychiatric Functions, and Seizure Timing in Children With Self-Limited Epilepsy With Centrotemporal Spikes.

    Tin O, Saltık S, Kara HÇ, et al.

    Journal of child neurology 2025; (40(5)):324-331 doi:10.1177/08830738241304864.

    PMID: 39676505
  5. 5

    Poor School Academic Performance and Benign Epilepsy with Centro-Temporal Spikes.

    Vetri L, Pepi A, Alesi M, et al.

    Behavioral sciences (Basel, Switzerland) 2023; (13(2)) doi:10.3390/bs13020106.

    PMID: 36829335
  6. 6

    EEG features in Encephalopathy related to Status Epilepticus during slow Sleep.

    Gardella E, Cantalupo G, Larsson PG, et al.

    Epileptic disorders : international epilepsy journal with videotape 2019; (21(S1)):22-30 doi:10.1684/epd.2019.1054.

    PMID: 31162114
  7. 7

    Encephalopathy Associated with Electrical Status Epilepticus of Sleep (ESES): A Practical Approach.

    RamachandranNair R

    Indian journal of pediatrics 2020; (87(12)):1057-1061 doi:10.1007/s12098-020-03422-9.

    PMID: 32632569
  8. 8

    Spike-Wave Index Assessment and Electro-Clinical Correlation in Patients with Encephalopathy Associated with Epileptic State During Slow Sleep (ESES / CSWS); Single-Center Experience.

    Öztoprak Ü, Yayici Köken Ö, Aksoy E, Yüksel D

    Epilepsy research 2021; (170()):106549 doi:10.1016/j.eplepsyres.2021.106549.

    PMID: 33450525
  9. 9

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

    Zhang Y, Li C, Zhou Y, et al.

    Seizure 2024; (119()):52-57 doi:10.1016/j.seizure.2024.05.012.

    PMID: 38796951
  10. 10

    Encephalopathy related to Status Epilepticus during slow Sleep: current concepts and future directions.

    Tassinari CA, Rubboli G

    Epileptic disorders : international epilepsy journal with videotape 2019; (21(S1)):82-87 doi:10.1684/epd.2019.1062.

    PMID: 31180330
  11. 11

    Long-term follow-up of cognitive functions in patients with continuous spike-waves during sleep (CSWS).

    Maltoni L, Posar A, Parmeggiani A

    Epilepsy & behavior : E&B 2016; (60()):211-217 doi:10.1016/j.yebeh.2016.04.006.

    PMID: 27240307
  12. 12

    Connectivity increases during spikes and spike-free periods in self-limited epilepsy with centrotemporal spikes.

    Goad BS, Lee-Messer C, He Z, et al.

    Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology 2022; (144()):123-134 doi:10.1016/j.clinph.2022.09.015.

    PMID: 36307364
  13. 13

    Encephalopathy with status epilepticus during sleep (ESES) induced by oxcarbazepine in idiopathic focal epilepsy in childhood.

    Pavlidis E, Rubboli G, Nikanorova M, et al.

    Functional neurology 2015; (30(2)):139-41 doi:10.11138/fneur/2015.30.2.139.

    PMID: 26415787
  14. 14

    Scalp-recorded high-frequency oscillations in atypical benign partial epilepsy.

    Qian P, Li H, Xue J, Yang Z

    Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology 2016; (127(10)):3306-13.

    PMID: 27579546

This page provides educational information about the SeLECTS and ESES epilepsy spectrum. Always consult your pediatric neurologist to interpret your child's EEG results and discuss their specific symptoms, regression risks, or medication side effects.

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