The 6 operational criteria for defining interictal epileptiform discharges (IEDs) proposed by the International Federation of Clinical Neurophysiology simplify IED identification into a series of systematic feature extraction tasks. The presence of at least 4 criteria defines a sharp transient as epileptiform.1 The criteria displayed in the teaching graphic (Figure) can be used to train novice EEG readers how to critically appraise the components of a sharp transient.2,3 The visual-based, systematic teaching method ensures that trainees can accurately and reliably identify IEDs on EEG.4 We use this graphic to teach the criteria to trainees and as a visual aid when applying the criteria during supervised EEG reading sessions.
(1) Sharp or spiky morphology (20–200 milliseconds); (2) different wave duration than background activity; (3) waveform asymmetry; (4) after-going slow wave; (5) disruption of background activity: flattening or low-voltage alpha or beta frequency activity after (most frequently) or before sharp transient; (6) distribution suggestive of cerebral source/physiologic field. Criteria 4 and 5 are independent. IFCN = International Federation of Clinical Neurophysiology.
Author Contributions
F.A. Nascimento: drafting/revision of the manuscript for content, including medical writing for content; major role in the acquisition of data; study concept or design; analysis or interpretation of data. S. Beniczky: drafting/revision of the manuscript for content, including medical writing for content; major role in the acquisition of data; study concept or design; analysis or interpretation of data.
Study Funding
No targeted funding reported.
Disclosure
F.A. Nascimento is a former member of the Neurology® Resident & Fellow Section editorial team and is deputy editor of the Neurology Minute® Daily Briefing. S. Beniczky reports no disclosures relevant to the manuscript. Go to Neurology.org/NE for full disclosures.
Footnotes
Go to Neurology.org/NE for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article.
Submitted and externally peer reviewed. The handling editor was Editor Roy Strowd III, MD, MEd, MS.
- Received December 29, 2022.
- Accepted in final form April 4, 2023.
- © 2023 American Academy of Neurology
This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (CC BY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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