Sport-related concussion is an inherent risk to athlete health in contact and collision sports. Both short- and long-term risks are associated with the injury. Short-term, athletes may develop post-concussion syndrome (PCS), the persistence of cognitive, physical, and emotional symptoms for weeks or months after injury. Athletes who return to play (RTP) prematurely are at increased risk for lower extremity injury and repeated concussion injuries. Long-term, history of multiple concussions have been linked to neurodegenerative diseases. Due to these risks, concussion assessments must be sensitive to the injury and useful in the diagnosis, recovery, and RTP phases of the injury.
Sideline clinical assessments for symptoms, balance, and neurocognition among other domains are utilized to meet the recommendation for a multidomain approach to concussion assessment. Particularly in balance testing, there is concern that standard observational sideline tests do not measure lasting balance deficits for more than three days post-injury. Biomechanical balance measures appear to longitudinally assess sensory integration capabilities of concussed athletes better than clinical observational scoring. This dissertation measured the sensitivity of biomechanical balance measures to concussion longitudinally in athletes up to 6 months post-injury, and in athletes reporting a history of concussion. Sensitive biomechanical balance measures were then assessed in multidomain logistic regression models to determine the most longitudinally sensitive combination of multidomain assessments to concussion.
A combined cohort of 186 National Collegiate Athletic Association (NCAA) Division I (DI) athletes at the University of Denver participated in this research. Each athlete participated in an extensive data collection, including instrumented standing and functional balance tasks, neurocognitive assessment, oculomotor assessment, vestibular-ocular assessment, a blood draw, and symptom scoring. Specific Aim 1 assessed the discriminative ability and sensitivity to concussion of linear measures of biomechanical balance in a comparison of non-concussed athletes to concussed athletes tracked longitudinally up to 6 months post-injury. Specific Aim 2 evaluated group differences between non-concussed athletes and those with a documented history of concussion more than 6 months post-injury of linear and nonlinear measures of biomechanical balance. Specific Aim 3 evaluated the longitudinally sensitive and discriminatory measures of biomechanical balance from Aim 1 in multidomain logistic regression models to determine the most longitudinally sensitive combination of multidomain assessments.
Together, these Specific Aims indicate that linear measures of COP velocity in standing balance discriminate well between non-concussed and acutely concussed athletes and are longitudinally sensitive to concussion up to 6 months post-injury. These measures also show deficits in athletes with a history of concussion, indicating a potential lack of vestibular and sensorimotor integration recovery leading to reduced neuromuscular functioning. Lastly, these measures on their own generate a model that is longitudinally sensitive to concussion and may aid in concussion recovery, rehabilitation, and RTP decision making