Persistent, Long-term Cerebral White Matter Changes after Sports-Related Repetitive Head Impacts

• Published in: PloS one Vol. 9; no. 4; p. e94734
• Main Authors: Bazarian, Jeffrey J., Zhu, Tong, Zhong, Jianhui, Janigro, Damir, Rozen, Eric, Roberts, Andrew, Javien, Hannah, Merchant-Borna, Kian, Abar, Beau, Blackman, Eric G.
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01.04.2014; Public Library of Science (PLoS)
• Subjects: Accelerometers; Alzheimer's disease; Alzheimers disease; Analysis; Anisotropy; Apolipoproteins; Athletes; Autoantibodies; Balance; Biology and Life Sciences; Biomedical engineering; Brain; Brain - diagnostic imaging; Brain - physiopathology; Brain Concussion - diagnosis; Brain Concussion - physiopathology; Brain research; Chronic brain injury; Chronic traumatic encephalopathy; Cognition; Cognitive ability; Concussion; Contact sports; Correlation analysis; Craniocerebral Trauma - diagnosis; Craniocerebral Trauma - physiopathology; Dementia; Dentistry; Diffusion Tensor Imaging; Division; Emergency medical care; Encephalopathy; Football; Football - injuries; Football players; Gene amplification; Head; Head injuries; Helmets; Humans; Injuries; Magnetic resonance imaging; Male; Medical imaging; Medicine; Medicine and Health Sciences; Neuroimaging; Neurosciences; Observational studies; Physical Sciences; Prospective Studies; Protective equipment; Radiography; Risk factors; Rugby; S100b protein; Seasons; Substantia alba; Time Factors; Trauma; Traumatic brain injury; Universities; White Matter - physiopathology; Young Adult; New York; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0094734

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.