New Evidence Shows that One Season of High School Football Can Cause Microstructural Changes in the Brain
Researchers from Berkeley, Duke, UNC Chapel Hill and University of Arizona used a new type of MRI called “diffusion kurtosis imaging” (“DKI”) to take brain scans of 16 high school football players, ages 15 to 17, before and after a single season of football. DKI is an extension of Diffusion Tensor Imaging, (DTI) discussed in prior posts. Early studies suggest that it outperforms DTI in capturing certain microstructural changes in the brain. The football players who were scanned all wore helmets and none of them were diagnosed with a concussion. The researchers also measured head impact exposure during every practice and game using the Head Impact Telemetry (HIT) system, which has been widely used in other head impact studies. The study, which is the cover story of the November issue of the journal Neurobiology of Disease, is one of the first to look at how impact sports affect the brains of children at this age.
The researchers found significant changes in the structure of the grey matter in the front and rear of the brain, where impacts are most likely to occur, as well as changes to structures deep inside the brain. These structural changes correlated with the frequency of head impacts, which, as the authors conclude “suggest(s) that DKI imaging of gray matter may yield valuable biomarkers for evaluating brain injuries associated with subconcussive head impacts in contact sports.” The most significant structural changes were found on the opposite side of the brain from impact, suggesting that “contracoup” injury may be the most prominent.
“It is becoming pretty clear that repetitive impacts to the head, even over a short period of time, can cause changes in the brain,” said study senior author Chunlei Liu, a professor of electrical engineering and computer sciences and a member of the Helen Wills Neuroscience Institute at UC Berkeley. “This is the period when the brain is still developing, when it is not mature yet, so there are many critical biological processes going on, and it is unknown how these changes that we observe can affect how the brain matures and develops.”
It should be noted that testing did not indicate any change in the athletes’ cognitive function over the course of the season, and it is yet unclear whether the changes in their brains are permanent. Nevertheless, the results raise serious concerns about the impact of football on this young population.