SREDA on EEG: the benign pattern that mimics a seizure

Subclinical rhythmic electrographic discharge of adults · Benign variants

Abrupt parietal rhythmic theta with no clinical change and no post-ictal slowing. Simulated trace, longitudinal bipolar channels. Open in the interactive viewer

What it looks like

Abrupt, sharply contoured 5–7 Hz rhythmic theta over parietal and posterior temporal regions, usually bilateral, lasting from 20 seconds to a few minutes, in an awake adult, typically over 50 years. It looks like a seizure and is not one. ^3,11

What it means at the bedside

There is no clinical change, no post-ictal slowing and little evolution in frequency or field. Test the patient during the run: normal responses and normal background afterwards settle it.

Benign variantSeizure mimic

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Sources

Kane N, et al. A revised glossary of terms most commonly used by clinical electroencephalographers and updated proposal for the report format of the EEG findings (IFCN, 2017). Clin Neurophysiol Pract 2017;2:170–185. doi.org/10.1016/j.cnp.2017.07.002
Britton JW, et al. Electroencephalography (EEG): An Introductory Text and Atlas of Normal and Abnormal Findings in Adults, Children, and Infants. American Epilepsy Society, 2016 (free, NCBI Bookshelf). www.ncbi.nlm.nih.gov/books/NBK390354/

SREDA on EEG: the benign pattern that mimics a seizure

What it looks like

What it means at the bedside

Sources

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