Indications and diagnostic yield of emergency electroencephalography (EEEG) in an “era” of electrical status epilepticus

Introduction: The electroencephalogram (EEG) is a unique and valuable measure of the brain's electrical function. The use of EEG in emergent conditions has been boosted with the definition of electrical status epilepticus (ESE), however the precise role and value of EEG in emergent conditions have yet to be clearly defined. Therefore, our objective was to determine the indications and the yield of EEG in an emergency setup.

Method: A descriptive cross sectional study, 20 min standard digital EEGs (10–20 system) were performed. Individual bias was minimized by independent reporting done by two. Authors retrospectively reviewed the reports of eEEGs performed over a period of 12 months.

Results: A total number of 1028 were performed, out of which 166 (16.1%) through emergent requests, nullified 11 due to inadequate information. The mean age of eEEG was 22.0 years, no significant difference compared to routine-EEG (rEEG), Sex-male 57.8% for eEEG, 48.2% for rEEG (p < 0.05). The commonest clinical indication for eEEGs was altered level of consciousness 78 (46.9%). None suspected ESE on clinical grounds. The sensitivity of eEEGs for positive yield was 27.1%. Twenty-one had inter-ictal-epiletiform discharges (14 = focal), 16 had background slowing (12 = diffuse), only 4 had ESE (diffuse discharges). Moreover, 2 had burst-suppression, 1 spindle-coma and 1 periodic-lateralizedepileptiform-discharge. Majority (68.2%) with reduced level of consciousness had background slowing; only 1 had ESE.

There was no significant difference between the sensitivity of eEEG versus rEEG (p > 0.05).

Conclusion: Reduced level of consciousness is the comments indication for eEEG, only a minority had ESE. Sensitivity of eEEG for a positive yield is the same as of routine EEG.