Even without concussions, youth football alters brain structure
December 6, 2016
Over the past few years, health and specifically brain health have become extremely discernable parts of football. Every NFL player who suffers a concussion must pass a series of tests before playing or practicing again, and there is a neurological consultant on the sidelines of every game.
Concussions in college and professional games have been the primary focus, but new research from Wake Forest Baptist Medical Center has shown that even non-concussive hits can alter the structure of the brain at the cellular level.
The study, published in the journal Radiology, not only illustrated that a season’s worth of hits alters how the white matter of the brain is put together. More shockingly, the study showed that these changes occurred in youth football players.
Christopher Whitlow, M.D., Ph.D., followed 25 youth football players between ages eight and 13 for a whole season using Head Impact Telemetry Systems (HITS). Each HITS system is made up of several accelerometers placed in a football helmet that can tell where a hit comes from, how hard the hit is and how the head moves after a hit. HITS systems are used in the NFL and NCAA, but Whitlow used them as a means of finding the average amount of impact a youth player experiences in a season.
The researchers used several brain imaging techniques to examine the structure of the players’ brains before the season started and after the season ended. They specifically looked at the brain’s white matter, which is the collection of the signal-carrying pieces of the brain’s neurons. The white matter is responsible for the millions of connections that hold memories and process thought.
MRI images show clear changes in how the white matter was oriented. In the graphic to the right, the first image shows the brain before the season, the second shows the brain after the season and the third is an overlay of the two. In the overlay image, you can see the differences are especially pronounced near the meeting of the white and gray matter.
To examine these changes further, Whitlow and his colleagues used a type of advanced MRI imaging called diffusion tensor imaging, or DTI. DTI measures how fluids move in the brain as a function as of brain geometry. Brain fluids need to move in very specific ways to keep nerves and their support cells working at full capacity, so DTI images can indicate alterations to the brain at a microscopic level.
The flow of water in the brain is supposed to be relatively uniform, a smooth, orderly movement through the white matter that the DTI scans describe as a high value of fractional anisotropy. The researchers saw that after the season was over, the level of fractional anisotropy decreased, signaling a more erratic flow in the white matter.
Whitlow says that the decrease in that fractional anisotropy measurement has been seen before in other patients with more significant traumatic brain injuries and has been linked to cognitive issues in brain injury patients, but the football players in this study did not show any signs of those issues. Long-term studies, Whitlow says, will be needed to see how these sorts of low-level impacts affect mental health over years.
Still, there is physical evidence that these hits can alter the brain. Regardless of how those changes manifest later in life these changes are worth further study as they could affect the lives of the roughly three million youth athletes who take part in one of America’s favorite sports.
Daniel covers science, medicine, engineering and the environment in North Carolina.