Time to Detection of the First Seizure in Patients With Nonconvulsive Status Epilepticus in the Neurological Intensive Care Unit

Abstract

Video-EEG monitoring is often used to detect nonconvulsive status epilepticus (NCSE) in critical care patients. Short recording durations may fail to detect seizures. In this study, we investigated the time required to record the first ictal event, and whether it could be correlated with some clinical or EEG parameters. Video-EEG recordings of patients who were followed up in our neurological intensive care unit were evaluated retrospectively. The EEG recordings of patients with NCSE were reviewed to determine the timing of the first seizure occurrence. Demographic data and EEG findings were obtained from patient charts and EEG reports. Possible correlations between the presence of periodic discharges (PD), Glasgow Coma Scale (GCS) score and early seizure detection (defined as a seizure within the first hour of recording) were explored statistically. Out of 200 patients who underwent video-EEG monitoring, we identified 30 cases (15%; 18 male, 12 female; age 24-86 years; mean recording duration 99 hours) with NCSE. The first seizure was recorded within 0 to 1 hour in 22 patients (73%) and within 1 to 12 hours in 6 patients (22%). Interictal PDs were identified in 19 patients (63%). GCS score was ≤8 in 16 patients (53%). There was no correlation between early seizure detection and PDs (p=1.0) or GCS score (P = .22). In our study, >90% of the seizures were captured within 12 hours. This finding suggests that most of the NCSE cases can be identified even in centers with limited resources. The presence or absence of PDs or GCS score does not predict the timing of the first seizure.

Keywords: GCS score; intensive care unit; nonconvulsive status epilepticus; periodic discharges; time to first seizure.