 Despite advances that have been made in the care of patients after severe brain injury, TBI continues to confer a very high morbidity and mortality. The development of effective treatments to minimize the morbidity and mortality following TBI has been hindered due to a fundamental lack of understanding of the factors that contribute to secondary injury after the initial inciting traumatic event. By better understanding mechanisms of secondary brain injury after TBI, such as CSD, as well as methods for monitoring for pathologic events, there will be more opportunities to develop new treatments. This is a preliminary study with the goal of better characterizing CSD following severe TBI. 