I NVITED R EVIEW Consensus Statement on Continuous EEG in Critically Ill Adults and Children, Part I: Indications Susan T. Herman,* Nicholas S. Abend,† Thomas P. Bleck,‡ Kevin E. Chapman,§ Frank W. Drislane,* Ronald G. Emerson,k Elizabeth E. Gerard,¶ Cecil D. Hahn,# Aatif M. Husain,**†† Peter W. Kaplan,‡‡ Suzette M. LaRoche,§§ Marc R. Nuwer,kk Mark Quigg,¶¶ James J. Riviello,## Sarah E. Schmitt,*** Liberty A. Simmons,††† Tammy N. Tsuchida,‡‡‡ and Lawrence J. Hirsch§§§ Introduction: Critical Care Continuous EEG (CCEEG) is a common procedure to monitor brain function in patients with altered mental status in intensive care units. There is significant variability in patient populations undergoing CCEEG and in technical specifications for CCEEG performance. Methods: The Critical Care Continuous EEG Task Force of the American Clinical Neurophysiology Society developed expert consensus recommenda- tions on the use of CCEEG in critically ill adults and children. Recommendations: The consensus panel recommends CCEEG for diagnosis of nonconvulsive seizures, nonconvulsive status epilepticus, and other paroxysmal events, and for assessment of the efficacy of therapy for seizures and status epilepticus. The consensus panel suggests CCEEG for identification of ischemia in patients at high risk for cerebral ischemia; for assessment of level of consciousness in patients receiving intravenous sedation or pharmacologically induced coma; and for prognostication in patients after cardiac arrest. For each indication, the consensus panel describes the patient populations for which CCEEG is From the *Comprehensive Epilepsy Program, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, U.S.A.; †Departments of Neurology and Pediatrics, Perelman School of Medicine, Children’s Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, U.S.A.; ‡Departments of Neurological Sciences, Neurosurgery, Medicine, and Anesthesiology, Rush Medical College, Chicago, Illinois, U.S.A.; §Department of Pediatrics and Neurology, University of Colorado, Boulder, Colorado, U.S.A.; kDepartment of Neurology, Hospital for Special Surgery, NewYork-Presbyterian Hospital/Weill Cornell Medical College, New York, New York, U.S.A.; ¶Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, U.S.A. #Division of Neurology, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada; **Department of Neurology, Duke University Medical Center, Durham, North Carolina, U.S.A.; ††Neurodiagnostic Center, Veterans Affairs Medical Center, Durham, North Carolina, U.S.A.; ‡‡Department of Neurology, Johns Hopkins Bayview Medical Center, Baltimore, Maryland, U.S.A.; §§Department of Neurology, Emory University School of Medicine, Atlanta, Georgia, U.S.A.; kkDepartment of Neurology, David Geffen School of Medicine and Clinical Neurophysiology, Ronald Reagan UCLA Medical Center, Los Angeles, California, U.S.A.; ¶¶FE Dreifuss Comprehensive Epilepsy Program, Department of Neurology, Univer- sity of Virginia, Charlottesville, Virginia, U.S.A.; ##NYU Division of Child Neurology, Columbia University Medical Center, New York, New York, U.S. A.; ***Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, U.S.A.; †††School of Clinical Neurophysiology, Crozer-Chester Medical Center, Upland, Pennsylvania, U.S. A.; ‡‡‡Department of Neurology and Pediatrics, Children’s National Medical Center, George Washington University School of Medicine, Washington, District of Columbia, U.S.A.; and §§§Department of Neurology, Yale Comprehensive Epilepsy Center, Yale School of Medicine, New Haven, Connecticut, U.S.A. Address correspondence and reprint requests to Susan T. Herman, MD, Beth Israel Deaconess Medical Center, Baker 5, 330 Brookline Avenue, Boston, MA 02215, U.S.A.; e-mail: sherman2@bidmc.harvard.edu. Copyright O 2015 by the American Clinical Neurophysiology Society ISSN: 0736-0258/15/3202-0087 indicated, evidence supporting use of CCEEG, utility of video and quantitative EEG trends, suggested timing and duration of CCEEG, and suggested frequency of review and interpretation. Conclusion: CCEEG has an important role in detection of secondary injuries such as seizures and ischemia in critically ill adults and children with altered mental status. Key Words: EEG, EEG monitoring, Quantitative EEG, Seizure, Nonconvulsive seizure, Status epilepticus, Nonconvulsive status, epilepticus, Intensive care unit, Critical care, Adults, Children. (J Clin Neurophysiol 2015;32: 87–95) C ritically ill patients are at high risk for a variety of neurologic insults, including seizures, ischemia, edema, infection, and increased intracranial pressure, which can result in permanent neurologic disability if untreated. Despite these risks, there are few techniques for continuously monitoring brain function. EEG measures the brain’s electrical activity, can be recorded continuously at the bedside, has good spatial and excellent temporal resolution, and is sensitive to changes in both brain structure and function (Nuwer, 1994). Over the past decade, technical advances have improved the efficiency of continuous EEG (CEEG) recording and remote review, leading to a greater than fourfold increase in the number of CEEGs performed in intensive care units (ICUs) (Ney et al., 2013). Recent surveys, however, show variability in why and how CEEG is performed in the ICU (Abend et al., 2010; Gavvala et al., 2014; Sanchez et al., 2013a), highlighting the need for clinical guidance on this expensive and labor-intensive procedure. Critical care continuous EEG (CCEEG) refers to the simul- taneous recording of EEG and clinical behavior (video) over extended time periods (hours to weeks) in critically ill patients at risk for secondary brain injury and neurologic deterioration. Critical care continuous EEG is usually performed in an ICU setting, but this varies by hospital and some patients may be in step-down units or general medical or surgical units. Critical care continuous EEG typically includes simultaneous video recording and may include graphical displays of quantitative EEG (QEEG) trends. The goal of CCEEG is to identify changes in brain function, such as non- convulsive seizures (NCS) or ischemia, which may not be evident by neurological examination alone, to facilitate early identification and management of these abnormalities. This consensus statement applies only to critically ill adult and pediatric patients. It does not apply to long-term monitoring of awake and alert patients with epilepsy, sleep monitoring, or intraoperative monitoring. Separate recommendations have been developed by the Journal of Clinical Neurophysiology Volume 32, Number 2, April 2015