A new study published in the Journal of the American Medical Association finds that US college football players have smaller brains than other college students. The study found that the hippocampus, a region of the brain associated with learning and memory, was 17 percent smaller in football players without a history of concussion than age-matched college students, while this region of the brain was 26 percent smaller in football players who did have a history of concussions.
For this study, researchers were able to recruit 50 NCAA Division I football players. Of these, 25 had a history of at least one concussion, or mild traumatic brain injury (mTBI), while 25 had no such history. They were then compared with 25 age- and education-matched controls. Using a magnetic resonance imaging (MRI) scan to get detailed photos of the brain, it was found that all of the college football players had smaller brain volumes in both the left and right hippocampus compared to the control group, and that both sides were smaller still in those players with a history of concussion.
What is alarming is that the total number of concussions, however, was not associated with the size of the hippocampus on either side of the brain, suggesting that, amongst these college football players at least, having even one concussion was associated with smaller volumes in this region of the brain. Furthermore, the hippocampus on the left side of the brain was smaller in players who had played football for a greater number of years. However, given the nature of the research, it is possible that the college football players may have had smaller hippocampi prior to entering the sport.
Researchers then used an online cognitive testing battery to examine the memory of the football players and found that concussion history did not have any effect on cognitive performance on those tests. However, reaction time was associated with the number of years played, with football experience being associated with decreased performance on the reaction time test.
Overall, this study suggests that exposure to tackle football is associated with both decreased brain volumes in the hippocampus and slowed reaction time. While the current study did not find any difference between the concussed and non-concussed football players on cognitive performance, this study was small, and may not have been able to detect any true differences that may have existed. Furthermore, the authors did not compare the football players with the control group, so associations between exposure to tackling or concussion history and cognitive performance is not available. Also, the cognitive testing battery used by the research team, the ImPACT neuro-cognitive test, has been criticized by other scientists in the past for not being a reliable test of post-concussion symptomology and recovery.
This study is just one in a litany of new research that has surfaced lately on the topic of mTBI and football player safety. Recent studies have shown an increase in the number of mTBI cases in the USA, while another study indicated that males take longer to fully recover from the effects of concussion. In addition, a new study presented to the American Academy of Neurology’s annual meeting earlier this year found that football helmets, while effective in preventing skull fractures, do little to protect against concussions. As the brains of young adults have still not fully completed maturing, the exposure to tackle football during adolescence and early adulthood is potentially more risky, as the potential for long-term effects may be greater, including the possibility of creating smaller brains. Ultimately these studies suggest that player safety should be a paramount concern for all youth and college football organizations.
by Bryan A. Jones