Concussion Among Military Service Academy Members: Identifying Risk Factors, Recovery Trajectories, And The Role Of Mental Health

Background Concussion, or mild traumatic brain injury, affects 42 million individuals worldwide each year. Most research to date has focused concussion risk, recovery, and outcomes across groups. Furthermore, most studies have been composed of males, varsity athletes, evaluated a single concussion type (e.g. sport versus non-sport related), or had a cross-sectional design. Objective The objective of the current study is to leverage a prospective multisite prospective study of concussion to identify individual characteristics associated with concussion risk and recovery. Additionally, the relationship between concussion and psychological symptoms will be elucidated to determine whether concussion influences subsequent psychological symptoms or if psychological symptoms also influence concussion risk. Methods Cadets enrolled in the Concussion Assessment, Research and Education Consortium were utilized in this series of dissertation projects. Linear mixed models were implemented to identify demographic and individual factors associated with concussion risk. Next, survival analyses identified factors related to symptom and return to activity protocol durations. Further exploring the relationship between symptom and recovery, Classification and Regression Tree analysis was used to classify normal and abnormal post-concussion symptom durations based on individual acute concussion symptoms. Finally, path analysis evaluated the relationship between concussion and psychological symptoms. Results Individual risk factors for concussion in included female sex, varsity athlete status, freshmen, having a previous concussion, headaches, ADD/ADHD, and greater BSI-18 somatization symptoms. Each of these factors were associated with a 1.02-2.73 increased concussion risk. Similar risk factors were observed for concussions caused by sport or academy training-related activities. Free time-related concussions were only associated with female sex, freshmen, and previous concussion. These results indicate that females, freshmen, and those with a previous concussion are at greatest risk for an incident concussion of any type. Separate factors were associated with symptom duration and RTA protocol duration. Thus, symptom duration and RTA protocol durations are likely related but separate entities within total time loss after a concussion. Specifically, the acute number of symptoms had the most consistent and largest effect on recovery durations. Examining individual symptoms, the symptom difference scores between baseline and 24-48 hours post-concussion best predicted normal versus abnormal recovery. Specific symptoms classifying normal versus abnormal recovery were balance problems, dizziness, trouble falling asleep, nausea, and neck pain. Finally, the relationship between psychological symptoms and concussion was examined. Results demonstrated that baseline somatization had the strongest association with subsequent concussion and future somatization symptoms. Moreover, an incident concussion was associated with lower depression, anxiety, and somatization symptoms, albeit the size of these effects were small. Conclusion Overall, results indicate that there is a constellation of individual and individual factors associated with concussion risk and recovery. In particular, specific individual symptoms predict normal and abnormal recovery. The individual symptoms may represent the most informative symptoms related to concussion recovery and also points of clinical intervention. Additionally, there is a bidirectional relationship between concussion and psychological symptoms which encourages future studies to account of baseline psychological symptoms or mental health.PHDKinesiologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/144005/1/kloconn_1.pd