Continuous EEG Monitoring-The Neurologist's Crystal Ball

Time to Epileptiform Activity and EEG Background Recovery Are Independent Predictors After Cardiac Arrest Westhall E, Rose I, Rundgren M, Bro-Jeppesen J, Kjaergaard J, Hassager C, Lindehammar H, Horn J, Ullen S, Nielsen N, Friberg H, Cronberg T. Clin Neurophysiol. 2018;129:1660-1668. https://doi.org/10.1016/j.clinph.2018.05.016 Objective: To investigate the temporal development of electroencephalogram (EEG) and prognosis.

Prospective observational substudy of the Target Temperature Management trial. Six sites performed simplified continuous EEG monitoring (cEEG) on comatose patients after cardiac arrest, blinded to treating physicians. We determined time points of recovery of a normal-voltage continuous background activity and the appearance of an epileptiform EEG, defined as abundant epileptiform discharges, periodic/rhythmic discharges, or electrographic seizure activity.

One hundred thirty-four patients were included, of which 65 had a good outcome. Early recovery of continuous background activity (within 24 hours) occurred in 72 patients and predicted good outcome since 55 (76%) had good outcome, increasing the odds for a good outcome 7 times compared to a late background recovery. Early appearance of an epileptiform EEG occurred in 38 patients and 34 (89%) had a poor outcome, increasing the odds for a poor outcome 6 times compared to a late debut. The time to background recovery and the time to epileptiform activity were highly associated with outcome and levels of neuron-specific enolase. Multiple regression analysis showed that both variables were independent predictors.

Time to epileptiform activity and background recovery are independent prognostic indicators.

Patients with early background recovery combined with late appearance of epileptiform activity may have a good outcome.