Prognostic value of EEG monitoring after status epilepticus: a prospective adult study

Despite the significant morbidity and mortality associated with status epilepticus (SE), little is known about changes in cortical function that occur after SE. We evaluated cortical function after clinical SE using continuous EEG monitoring lasting at least 24 h in 180 patients admitted to the Medical College of Virginia Hospitals (MCVH). The major EEG patterns observed after SE were a normal record, burst suppression, after SE ictal discharge (ASIDs), periodic lateralizing epileptiform discharges (PLEDs), attenuation, focal and generalized slowing, and epileptiform discharges. Normalization of the EEG after SE was highly correlated with good outcome. The presence of burst suppression and ASIDs was highly statistically significantly associated with mortality. PLEDs were also highly correlated with mortality, but not to the same degree as burst suppression and ASIDs. In addition, these EEG patterns were still significantly correlated with morbidity and mortality when we controlled for etiology using multivariate logistic statistical analysis. Persistent ictal activity was observed in many patients despite control of clinical seizure activity, indicating the importance of EEG monitoring to determine treatment patterns after clinical seizure activity in SE is controlled. The results indicate that certain EEG patterns (normalization of the EEG, ASIDs, burst suppression and PLEDs) are useful predictors of outcome in SE in addition to etiology. EEG monitoring after control of clinical SE is important to guide treatment of SE and is a useful technique for evaluating prognosis.