By: Dianne Langford, PhD
You may have seen the recent headlines about a new study that looked at the brains of former NFL players and found Chronic Traumatic Encephalopathy (CTE) in a full 99 percent of them. While the headlines make it seem like CTE may be unavoidable for players, the reality is that we still don’t know how often it occurs. That’s because all of the 111 players whose brains were donated for the study, which took place at Boston University, were known to be suffering from signs and symptoms of CTE while alive. In fact, that’s why they donated their brains. So, the study doesn’t give us a good estimate of how many total current or former NFL players may be suffering from CTE, or how many may develop it in the future. But what we do know is that there does appear to be a strong link between playing football and CTE.
We also see CTE develop in combat veterans exposed to blast trauma, in mixed martial arts fighters, and boxers. Of course, what all of these people have in common is trauma to the head, which we know is definitely a risk factor. It seems likely that the number of head impacts sustained, the force from these impacts and the location of the head injury correlate with developing CTE. The position of the player may influence their risk of head injuries and therefore the risk of CTE. For example, a linebacker may be exposed to more head impacts than a quarterback or kicker. On the other hand, we know that many players exposed to seemingly identical head trauma don’t get CTE. So, head trauma can’t be the only factor.
Researchers are now exploring the many other potential factors that, when combined with head impact, may influence the likelihood of developing CTE. For example, some research suggests that a player’s hydration level could influence the risk of and severity of a concussion, as well as recovery from the concussion. Likewise, intake of caffeine, alcohol, drug use, and even diet may play roles in whether someone is more susceptible to concussion, in the severity of a concussion, or in recovery afterward. In case that wasn’t enough, there are also neurobiological factors that may affect concussion risk and outcome, like sleep habits and genetic makeup. In fact, many studies are looking into whether our genes could actually mean some of us are more predisposed to developing CTE after multiple head injuries than others. Some genes may even help protect against CTE after head injuries.
In fact, studies at Temple University are looking at a group of athletes who sustained concussions to see if those who had worse outcomes have different gene sequences from those who recovered more quickly.
Although a lot more research needs to be done, we are getting closer to understanding the causes of CTE. For now, we know that not everyone with repeated head injuries will develop CTE, but it does increase the risk. The big question on everyone’s mind is: should we limit contact sports? Unfortunately, we just don’t know the answer. But in the future, we hope all of the exciting research being done right now will be able to give us the answers we seek.