Seizure burden in subarachnoid hemorrhage associated with functional and cognitive outcome.

Abstract

To assess the relationship between seizure burden on continuous EEG (cEEG) and functional as well as cognitive outcome 3 months after subarachnoid hemorrhage (SAH). The study included all consecutive patients with a spontaneous SAH admitted to the Columbia University Medical Center Neurological Intensive Care Unit and monitored with cEEG between 1996 and 2013. Seizure burden was defined as the duration, in hours, of seizures on cEEG. Cognitive outcomes were measured with the Telephone Interview for Cognitive Status (TICS, ranging from 0 to 51, indicating poor to good global mental status). Overall, 402 patients with SAH were included with a median age of 58 years (interquartile range [IQR] 46-68 years). The median duration of cEEG monitoring was 96 hours (IQR 48-155 hours). Seizures were recorded in 50 patients (12%), in whom the median seizure burden was 6 hours (IQR 1-13 hours). At 3 months, in multivariate analysis, seizure burden was associated with unfavorable functional and cognitive outcome. Every hour of seizure on cEEG was associated with an odds ratio of 1.10 (95% confidence interval [CI] 1.01-1.21, p = 0.04) to 3-month disability and mortality, and the TICS-score decreased, on average, by 0.16 points (adjusted coefficient -0.19, 95% CI -0.33 to -0.05, p = 0.01). In this study, after adjusting for established predictors, seizure burden was associated with functional outcome and cognitive impairment 3 months after SAH.