MRI shows measurable brain changes among children who played only one season of youth football, even without diagnosis of concussion, according to a study published in Radiology.
Researchers from North Carolina, Maryland, and Texas sought to examine the effects of subconcussive impacts on children aged 8 to 13 who played a single season of youth football on changes in specific white matter (WM) tracts as detected with diffusion-tensor imaging in the absence of clinically diagnosed concussions.
“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?” lead author Christopher T. Whitlow, MD, PhD, MHA, associate professor and chief of neuroradiology at Wake Forest School of Medicine in Winston-Salem, NC, said in a news release. “We wanted to see if cumulative sub-concussive head impacts have any effects on the developing brain.”
The study participants participated in both practices and games throughout the 2012 or 2013 seasons. During the 2012 season, reports of suspected concussions were made by player, parent, or coach. During the 2013 season, a certified athletic trainer was present during all games and practices, and evaluated players suspected of having concussions. If players were identified with symptoms of concussion they were evaluated by a sports medicine physician. Nine children played in both seasons; their second season was not included in the study. Four children with a history of concussion were also excluded, as were two who were diagnosed with concussion during the season. Twenty-five males, mean age 11.72, were evaluated for the study.
The study participants underwent pre- and post-season evaluation with multimodal neuroimaging, including diffusion tensor imaging (DTI) of the brain. Head impact data were recorded by using the Head Impact Telemetry system and quantified as the combined probability risk-weighted cumulative exposure (RWECP). The participants were evaluated for seasonal fractional anisotropy (FA) changes in specific WM tracts: the inferior fronto-occipital fasciculus (IFOF), inferior longitudinal fasciculus, and superior longitudinal fasciculus (SLF). Fiber tracts were segmented into a central core and two fiber terminals. The relationship between seasonal FA change in the whole fiber, central core, and the fiber terminals with RWECP was also investigated. Linear regression analysis was conducted to determine the association between RWECP and change in fiber tract FA during the season.
While none of the patients showed any clinical signs of concussion, the results showed statistically significant linear relationships between RWECP and decreased FA in the whole, core, and terminals of left IFOF. A trend toward statistical significance in right SLF was observed. A statistically significant correlation between decrease in FA of the right SLF terminal and RWECP was also observed.
“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,” Whitlow said. “These decreases in FA caught our attention, because similar changes in FA have been reported in the setting of mild TBI.”
“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,” Whitlow continued. “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.”