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

Understanding the EEG and Diagnostic Process

At a Glance

The most critical part of diagnosing SeLECTS is obtaining an EEG while the child is sleeping. The hallmark centrotemporal spikes are sleep-activated, meaning an EEG done only while awake may completely miss the diagnosis. MRIs are typically normal and used primarily to rule out structural issues.

An EEG (electroencephalogram) report can feel like a foreign language. However, for a child with SeLECTS, the EEG is the “gold standard” for diagnosis [1]. It doesn’t just show that a seizure happened; it shows a specific electrical “fingerprint” that tells doctors exactly what kind of epilepsy your child has [2].

Why Sleep is Critical

The most important thing to know about a SeLECTS EEG is that it must include sleep. These specific brain waves are sleep-activated, meaning they may be rare or even absent while your child is awake but become much more frequent and intense during NREM (Non-REM) sleep [3][4]. If an EEG is done only while the child is awake, the diagnosis might be missed entirely [5][6].

Demystifying the Jargon

If you are looking at your child’s EEG report, you will likely see several technical terms. Here is what they mean in plain English:

  • Centrotemporal Spikes (or Rolandic Spikes): These are the hallmark of the condition [7]. “Centrotemporal” refers to the specific part of the brain (the middle and side) where the activity is happening [2].
  • Triphasic Morphology: This describes the shape of the spike. A “triphasic” wave has three distinct parts or phases (up, down, up). It is the classic “look” of a SeLECTS spike [2].
  • Horizontal Dipole: This is a technical way of describing how the electricity is flowing. In SeLECTS, the spike has a “negative” end in one area and a “positive” end in another (the frontal region) [8][9]. This specific electrical orientation is a very strong indicator of SeLECTS [8].
  • Interictal Discharges: “Interictal” simply means “between seizures.” The spikes you see on the EEG are usually not actual seizures; they are just “background noise” that occurs between episodes [10].

Why the MRI is Usually Normal

While the EEG shows how the brain functions, an MRI (Magnetic Resonance Imaging) shows how the brain is built. In SeLECTS, the brain’s structure is almost always perfectly normal [11][12].

Doctors usually order an MRI only to rule out other things, such as a small growth or a structural scar, that could be causing seizures [11]. Once the MRI comes back “normal” and the EEG shows the “classic” centrotemporal spikes, doctors can be very confident in the SeLECTS diagnosis [1][11].

EEG Completeness Checklist

A high-quality EEG report for SeLECTS should ideally include the following:

  1. Recording of Sleep: Documentation that the child reached NREM sleep [2][13].
  2. Location: Clear identification of “centrotemporal” or “C3/C4” and “T3/T4” electrode locations [2].
  3. Activation Description: A note on whether the spikes increased during sleep (sleep activation) [3].
  4. Symmetry: Mention of whether spikes happen on one side of the brain (unilateral) or both (bilateral) [14].
  5. Background Activity: A statement that the rest of the brain’s “background” rhythm is normal [13].

Common questions in this guide

Why does an EEG for SeLECTS need to be done while my child is sleeping?
Centrotemporal spikes, the hallmark brain waves of SeLECTS, are sleep-activated. This means they often only appear or become much more frequent during non-REM sleep, so a waking EEG might miss the diagnosis entirely.
What are centrotemporal spikes on an EEG report?
Centrotemporal spikes are specific patterns of electrical activity in the middle and side areas of the brain. They are the classic electrical signature required to officially diagnose SeLECTS.
What does 'horizontal dipole' mean on my child's EEG?
A horizontal dipole describes the specific way electricity flows during a SeLECTS spike. It shows a negative charge in one area and a positive charge in the frontal region, which strongly confirms a typical SeLECTS pattern.
Why did the doctor order an MRI if the EEG already shows SeLECTS?
While an EEG confirms the electrical pattern of SeLECTS, an MRI is sometimes ordered to ensure the brain's physical structure is normal. This helps rule out other potential causes for the seizures, like structural scars or small growths.
Are the 'interictal discharges' on the EEG actual seizures?
'Interictal' means between seizures. The interictal discharges or spikes you see noted on the EEG report are usually not actual seizures, but rather the background electrical noise that occurs between episodes.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Does the EEG report show 'sleep activation,' and how significantly did the spikes increase during sleep?
  2. 2.Were the spikes localized only to the centrotemporal region, or were they found in other areas like the frontal lobe?
  3. 3.Was a 'horizontal dipole' noted, and does this confirm a typical SeLECTS pattern?
  4. 4.Based on this EEG, is an MRI necessary to rule out structural issues, or is the pattern diagnostic enough?
  5. 5.Does my child's EEG show any signs of continuous spikes during sleep that we should be worried about?

Questions For You

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References

References (14)
  1. 1

    Self-limited epilepsy with centro-temporal spikes: A study of 46 patients with unusual clinical manifestations.

    Galicchio S, Espeche A, Cersosimo R, et al.

    Epilepsy research 2021; (169()):106507 doi:10.1016/j.eplepsyres.2020.106507.

    PMID: 33296810
  2. 2

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

    Lu G, Cheng Y, Wang Y, et al.

    Clinical EEG and neuroscience 2024; (55(2)):265-271 doi:10.1177/15500594231182758.

    PMID: 37331959
  3. 3

    Sleep Related Epilepsy and Pharmacotherapy: An Insight.

    Kumar J, Solaiman A, Mahakkanukrauh P, et al.

    Frontiers in pharmacology 2018; (9()):1088 doi:10.3389/fphar.2018.01088.

    PMID: 30319421
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    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
  5. 5

    Auditory stimulation during sleep suppresses spike activity in benign epilepsy with centrotemporal spikes.

    Klinzing JG, Tashiro L, Ruf S, et al.

    Cell reports. Medicine 2021; (2(11)):100432 doi:10.1016/j.xcrm.2021.100432.

    PMID: 34841286
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    Benign epilepsy with centrotemporal spikes: Is there a thalamocortical network dysfunction present?

    Şanlıdağ B, Köken ÖY, Temel EÜ, et al.

    Seizure 2020; (79()):44-48 doi:10.1016/j.seizure.2020.04.003.

    PMID: 32416566
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    Seizures in self-limited epilepsy with centrotemporal spikes: video-EEG documentation.

    Ferrari-Marinho T, Hamad APA, Casella EB, et al.

    Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery 2020; (36(9)):1853-1857 doi:10.1007/s00381-020-04763-8.

    PMID: 32661641
  8. 8

    Reliability and availability of granger causality density in localization of Rolandic focus in BECTS.

    Dai XJ, Yang Y, Wang N, et al.

    Brain imaging and behavior 2021; (15(3)):1542-1552 doi:10.1007/s11682-020-00352-0.

    PMID: 32737823
  9. 9

    Ictal source imaging and electroclinical correlation in self-limited epilepsy with centrotemporal spikes.

    Alving J, Fabricius M, Rosenzweig I, Beniczky S

    Seizure 2017; (52()):7-10 doi:10.1016/j.seizure.2017.09.006.

    PMID: 28926747
  10. 10

    Benign epilepsy with centrotemporal spikes: Correlating spike frequency and neuropsychology.

    Tacke M, Rupp N, Gerstl L, et al.

    Acta neurologica Scandinavica 2018; (138(6)):475-481 doi:10.1111/ane.13015.

    PMID: 30259965
  11. 11

    Brain magnetic resonance imaging findings and brain volumetric differences in a large series of benign rolandic epilepsy.

    Salman R, Nasreddine W, Hannoun S, et al.

    The neuroradiology journal 2022; (35(6)):692-700 doi:10.1177/19714009221089022.

    PMID: 35467439
  12. 12

    Novel variant in CHRNA4 with benign childhood epilepsy with centrotemporal spikes and contribution to precise medicine.

    Neng X, Xiao M, Yuanlu C, et al.

    Molecular genetics & genomic medicine 2020; (8(7)):e1264 doi:10.1002/mgg3.1264.

    PMID: 32342646
  13. 13

    [The atypical developments of rolandic epilepsy are predictable complications].

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    Revista de neurologia 2015; (61(3)):106-13.

    PMID: 26178515
  14. 14

    Altered functional connectivity in newly diagnosed benign epilepsy with unilateral or bilateral centrotemporal spikes: A multi-frequency MEG study.

    Wang P, Li Y, Sun Y, et al.

    Epilepsy & behavior : E&B 2021; (124()):108276 doi:10.1016/j.yebeh.2021.108276.

    PMID: 34547687

This page explains SeLECTS diagnostic terminology for educational purposes only. Always consult your pediatric neurologist or epileptologist to accurately interpret your child's specific EEG and MRI results.

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