Jeffrey J. Bazarian, Tong Zhu, Jianhui Zhong, Damir Janigro, Eric Rozen, Andrew Roberts, Hannah Javien, Kian Merchant-Borna, Beau Abar, Eric G. Blackman; Persistent, Long-term Cerebral White Matter Changes after Sports-Related Repetitive Head Impacts; In PLoS One; 2014-04-16; 12 pages; landing.
Repetitive head impacts (RHI) sustained in contact sports are thought to be necessary for the long-term development of chronic traumatic encephalopathy (CTE). Our objectives were to: 1) characterize the magnitude and persistence of RHI-induced white matter (WM) changes; 2) determine their relationship to kinematic measures of RHI; and 3) explore their clinical relevance.
Prospective, observational study of 10 Division III college football players and 5 non-athlete controls during the 2011-12 season. All subjects underwent diffusion tensor imaging (DTI), physiologic, cognitive, and balance testing at pre-season (Time 1), post-season (Time 2), and after 6-months of no-contact rest (Time 3). Head impact measures were recorded using helmet-mounted accelerometers. The percentage of whole-brain WM voxels with significant changes in fractional anisotropy (FA) and mean diffusivity (MD) from Time 1 to 2, and Time 1 to 3 was determined for each subject and correlated to head impacts and clinical measures.
Total head impacts for the season ranged from 431–1,850. No athlete suffered a clinically evident concussion. Compared to controls, athletes experienced greater changes in FA and MD from Time 1 to 2 as well as Time 1 to 3; most differences at Time 2 persisted to Time 3. Among athletes, the percentage of voxels with decreased FA from Time 1 to 2 was positively correlated with several helmet impact measures. The persistence of WM changes from Time 1 to 3 was also associated with changes in serum ApoA1 and S100B autoantibodies. WM changes were not consistently associated with cognition or balance.
A single football season of RHIs without clinically-evident concussion resulted in WM changes that correlated with multiple helmet impact measures and persisted following 6 months of no-contact rest. This lack of WM recovery could potentially contribute to cumulative WM changes with subsequent RHI exposures.
- Cognitive testing is based on some software package
- Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT)
- Collins MW, Iverson GL, Lovell MR, McKeag DB, Norwig J, et al. (2003) On-field predictors of neuropsychological and symptom deficit following sports-related concussion. Clinical Journal of Sport Medicine 13: 222–229.
- Nicola Marchi, Jeffrey J. Bazarian, Vikram Puvenna, Mattia Janigro, Chaitali Ghosh, Jianhui Zhong, Tong Zhu, Eric Blackman, Desiree Stewart, Jasmina Ellis, Robert Butler, Damir Janigro; Consequences of Repeated Blood-Brain Barrier Disruption in Football Players; In PLoS One; 2013-03-06; landing; separately noted.