Abnormalities in brain white matter may occur in youth football players suffering sub-concussive head impacts

Written by Jonathan Wilkinson

Researchers from Wake Forest School of Medicine (NC, USA) have published findings reporting that changes in the brains of youth football players can be observed after a single season of play. What is of particular note is that these changes were seen in players that had not suffered a concussion during the season. This study has been published in Radiology and offers a new perspective into research regarding brain injury occurring in youth sports.

Christopher Winslow explained the premise of his team’s study: “Most investigators believe that concussions are bad for the brain, but what about the hundreds of head impacts during a season of football that don’t lead to a clinically diagnosed concussion? We wanted to see if cumulative sub-concussive head impacts have any effects on the developing brain.”

In their study, the investigators measured head impact data in 25 male youth football players aged between 8 and 13 years using the Head Impact Telemetry System. In combination with this, the participants underwent analysis of their brains’ white matter using diffusion tensor imagine, both pre- and post-season. Using diffusion tensor imaging, fractional anisotropy (FA) was measured in three white matter tracts: the inferior fronto-occipital fasciculus, the inferior longitudinal fasciculus and the superior longitudinal fasciculus. A significant correlation was found between head impacts and decreased fractional anisotropy measurements in these fiber tracts; decreased FA is often associated with brain abnormalities.

Whitlow expanded on these findings: “We found that these young players who experienced more cumulative head impact exposure had more changes in brain white matter, specifically decreased FA, in specific parts of the brain. These decreases in FA caught our attention, because similar changes in FA have been reported in the setting of mild TBI.”

However, the researchers note that more research will need to take place to assess the long-term effects of these apparent white matter changes. Whitlow explained: “We do not know if there are important functional changes related to these findings, or if these effects will be associated with any negative long-term outcomes. Football is a physical sport, and players may have many physical changes after a season of play that completely resolve. These changes in the brain may also simply resolve with little consequence. However, more research is needed to understand the meaning of these changes to the long-term health of our youngest athletes.”

Sources:Bahrami N, Sharma D, Rosenthal S et al. Subconcussive head impact exposure and white matter tract changes over a single season of youth football. Radiology doi: 10.1148/radiol.2016160564 (2016) (Epub ahead of print);