Project 459109

Cognitive problems and sleep complaints are among the most prevalent and chronic consequences of moderate to severe traumatic brain injury (TBI). Because bad sleep may worsen cognitive consequences of TBI such as poorer concentration, attention and memory, it is important to study how sleep is affected following TBI. One way to assess sleep is by studying the patterns of the electrical activity of the brain. These rhythmic activities are known as brain waves or as sleep oscillations to refer to brain activity during sleep. Whether the changes in sleep oscillations can explain sleep and cognitive complaints following TBI remains understudied. Previous research has found that TBI patients with more severe loss of brain white matter had abnormal sleep oscillations during non-rapid eye movement (NREM) sleep. Moreover, TBI patients with more severe injury were more dependent on sleep oscillations during NREM sleep for performance in a next-day memory test. Because moderate to severe TBI also results in loss of grey matter, particularly in brain regions with important roles in sleep and cognition, the next question to answer is how grey matter loss affects sleep oscillations in TBI patients. To answer this question, I will perform advanced neuroimaging and electroencephalography analysis (i.e., a method to record the electrical activity of the brain) to determine whether loss of grey matter is related to sleep oscillation characteristics in NREM sleep in adults with chronic TBI (i.e., 1-4 years post-injury). I will also determine whether grey matter loss and sleep oscillation characteristics are related to poor sleep, sleepiness and fatigue complaints reported by adults with TBI. This study may clarify why TBI patients frequently report poor sleep quality, fatigue and sleepiness and orient strategies for sleep disorder management. Better sleep could improve participation in rehabilitation sessions, brain recovery, return to school/work, and improved quality of life.