Electroencephalography (EEG) is an important and relatively inexpensive tool that allows intensivists to monitor cerebral activity of critically ill patients in real time. Seizure detection in patients with and without acute brain injury is the primary reason to obtain an EEG in the Intensive Care Unit (ICU); and in response to the increased demand for EEG, advances in quantitative EEG (qEEG) created an approach to review large amounts of data instantly. Today, rapid response EEG is now available to reduce the time to detect electrographic seizures in limited-resource settings. In this week's MasterClass, our hosts Dr Jon Rosenberg and Dr Stephan Mayer are joined by Dr Lawerence Hirsch, Co-Director of the Critical Care EEG Monitoring Program at Yale School of Medicine to discuss the evolution, value, and impact of brain monitoring with EEG in the critically ill.