Elucidating the Impact of Previous Head Injury on Cognition, Brain Structure, and Pathophysiology in Cognitively Normal Individuals Across the Adult Lifespan
Mild traumatic brain injury (mTBI), or concussion, is a common experience and awareness of mTBI has been increasing. There has been growing concern regarding potential long-term effects of concussion on cognition and risk for neurodegenerative disorders. This concern is heightened for athletic populations, particularly in high-contact sports, at risk for repetitive mTBI. Short-term effects of mTBI are heterogeneous, but well-documented, and the majority of individuals recover from post-concussive symptoms within several months. However, long-term effects of mTBI on brain structure and function are more poorly understood. The current studies sought to determine potential long-term effects of mTBI history and history of sports participation on 1) cognitive performance and change and 2) white matter hyperintensities (WMH) and hyperphosphorylated tau (pTau) burden, a protein associated with neurodegenerative disorders. Participants from the Dallas Lifespan Brain Study (DLBS) (aged 20-90 at baseline) completed two assessments related to head injury: the novel Head Injury Exposure and Assessment Data (HEAD) questionnaire and the current "gold standard," the Ohio State University TBI Identification Method (OSU TBI-ID). MTBI exposure variables were: number of mTBI and HEAD Total Index Score (overall seriousness of mTBI history) from the HEAD questionnaire and history of "concerning" head injury per OSU TBI-ID criteria. The HEAD questionnaire assessed history of participation in sports and average number of years played across no, limited, and high contact sports. Participants underwent longitudinal neuropsychological testing and magnetic resonance imaging, and cross-sectional positron emission tomography. Composite indices were created to represent the domains of Memory, Executive Functioning, and Processing Speed. The results did not find any evidence to suggest mTBI negatively affects cognitive performance, cognitive change, or perceived memory capacity. Longer participation in high-contact sports was not predictive of cognitive performance and there was no difference in mean cognitive index scores across highest level of contact sport played. There was also no evidence to support any relationship between history of mTBI/participation in high-contact sports and increased cerebral WMH volume or regional pTau burden. Thus, prior history of mTBI/participation in high-contact sports does not appear to be related to changes in brain structure or function in these otherwise healthy adults.
Brain Concussion, Brain Injuries, Cognition, Craniocerebral Trauma
University of Texas Southwestern Medical Center
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