Diagnosing and Monitoring Seizures in the ICU: The Role of Continuous EEG for Detection and Management of Seizures in Critically Ill Patients

Abstract

Recent advances in computer technology have made it possible to perform prolonged digital continuous video EEG monitoring of many critically ill patients simultaneously. Recent studies using continuous EEG monitoring (cEEG) have found that these patients, especially those with coma, acute brain injury, or prior clinical seizures, often have nonconvulsive seizures (NCSz), and that these may contribute to secondary brain injury. The majority of seizures in the critically ill are nonconvulsive and can only be identified with EEG recording. Rapidly improving quantitative EEG (qEEG) software speeds data review to allow screening of multiple prolonged recordings to detect NCSz and has the potential to provide continuous information about changes in brain function in real time at the bedside. Optimal sensitivity and specificity of qEEG tools are obtained with full electrode montages and careful maintenance of scalp electrodes. New electrode technologies, such as MRI-compatible electrodes, help reduce the burden on EEG technologists while limiting interruptions in recordings. In addition to detecting NCSz, cEEG can also be used for dynamic detection of other changes in brain function such as ischemia, and can be coupled with other modalities of monitoring brain physiology such as microdialysis, tissue oximetry, and intracranial electrophysiology. Together, these tools can allow early detection of brain at risk for injury and alert the physician to intervene before the damage becomes irreversible.