Bedside Quantitative EEG Complements the Clinical Exam in Comatose Patients with Brain Hemorrhages

Objective. We sought to determine EEG and multimodality monitoring parameters that best correlate with behavioral assessments of poor grade patients with acute brain injury.Background. Behavioral assessments of consciousness carry tremendous significance in guiding management, but are challenging in acutely brain-injured patients.Design/Methods. EEG, invasive multimodality monitoring brain monitoring, and behavioral assessments were collected during daily interruption of sedation in a consecutive series of 102 poor grade adults with brain hemorrhages. All patients were initially comatose and had invasive brain monitoring placed. Behavioral assessments were categorized into three groups: (1) comatose, (2) eye opening or attending towards a stimulus, and (3) command following. EEG features included power spectral density, permutation entropy, weighted pairwise phase consistency, weighted symbolic mutual information, and phase-amplitude coupling. Comparisons were made using bootstrapping methods and partial least squares regression.Results. We identified 464 artifact free EEG clips following behavioral assessments during daily interruption of sedation: 78 comatose, 246 with eye opening/attending, and 140 following commands. Using a linear model, spectral power in different frequency bands (theta, alpha, and gamma), alpha phase consistency in central and parieto-occipital regions, as well as permutation entropy best predicted the clinical state. Brain physiology measurements of intracranial pressure, cerebral blood flow, brain oxygen tension, and cerebral metabolism assessed using invasive multimodality monitoring only added marginal predictive accuracy to the model.Conclusion. EEG measures may complement the behavioral assessment of unconscious patients with brain hemorrhages shortly after injury. Disclosure: Dr. Claassen has received personal compensation for activities with the JSMF Foundation, Actelion, and SAGE Pharmaceutical. Dr. Velasquez has nothing to disclose. Dr. Emma has nothing to disclose. Dr. Witsch has nothing to disclose. Dr. Falo has nothing to disclose. Dr. Park has nothing to disclose. Dr. Agarwal has nothing to disclose. Dr. Schmidt has nothing to disclose. Dr. Schiff has nothing to disclose. Dr. Sitt has nothing to disclose. Dr. Naccache has nothing to disclose. Dr. Connolly has nothing to disclose. Dr. Frey has nothing to disclose.