The Wizard’s take on the Latest CTE Study on Football Players
All the rave in the past decade related to sports health has been CTE. If you ask the casual fan what CTE is you will probably get an answer somewhere along the lines of “That disease that football players get because they get hit too many times and it causes them to go crazy or commit suicide”.
And in all honesty that is a pretty good answer, considering that if you asked the same question around 15 years ago, you would have gotten the answer “What???”.
And this is for good reason. The term CTE, the abbreviation for Chronic Traumatic Encephalopathy, was first used in 1960’s and then used rarely until a 2005 article reported on the neurological findings of two retired NFL players. While the study itself did not conclude on the correlation of CTE to football related trauma, it laid the groundwork for further future research in the area and the eventual CTE craze that is 2017.
What is CTE?
Chronic Traumatic Encephalopathy is a term used to describe a degenerative brain disease that is thought to be caused by repetitive trauma to the head. The recent focus of CTE has been as it relates to football and other contact sports.
CTE as defined is thought of as a 4 phase disease. The early phases (1 & 2) are considered mild with late phases (3 & 4) considered severe. The early phases of CTE typically include symptoms such as irritability, headaches, dizziness, confusion (symptoms similar to that which might associate a concussion, but for a sustained duration). While later stages of CTE, as it progresses, are usually marked by more severe symptoms, such as but not limited to, cognitive decline & mental functioning, depression, coordination issues and visuospatial issues.
The phases of CTE noted above are typically considered to be primarily delayed onset (occurring up to years after the initial incidents). While someone who experiences heavy trauma to the head often has immediate symptoms such as concussions or loss of consciousness, the symptoms of CTE itself do not show up until many years after the initial repetitive trauma took place. In addition, while CTE is usually thought to be linked to blows to the head, concussions are not necessarily a marker that someone has developed or will or will not develop CTE.
Below is a video of Dr. Sanjay Gupta explaining the basics of CTE -
CTE in the Media
While CTE has just recently hit the mainstream media due to the explosion in news articles and research into CTE as it relates to football in the last 10 or so years, the study of CTE actually started almost 100 years ago. CTE was originally studied as it related to boxers, also called punch-drunk syndrome, due to the loss in mental functioning that had some similarities to the state of a person who is drunk. However, until just recently CTE was thought to be mostly contained to the boxing profession, as it was thought that the amount of repetitive, high impact head trauma that was needed to cause CTE could only be seen in the boxing profession. However, recent research has widened the scope of the sports that are being studied in regards to CTE, most notably football.
A recently widely quoted article from JAMA, indicates that 110 of 111 NFL players’ studies or 99% of NFL players had CTE. This has stricken fear into many a football-mom and even many players themselves, with a number of players at all levels of the sport choosing to stop playing the game early in order to maintain their health.
But What Does this Study Even Say?
The JAMA study noted above used a convenience study of 202 deceased football players from various levels of football as a sample. A study of convenience essentially means that the authors of the study used a readily available sample for convenience sake rather than a more scientific method of sampling. Which in and of itself is understandable, as CTE in this study, was only diagnosed post-mortem using brain samples.
In this study over 80% of participants brain samples were provided to the researchers by next of kin. Meaning that family who had football players experiencing unusual or troubling symptoms provided the samples to a Brain Bank for further testing. This would likely lead to a strong bias that the brain samples were given because the next of kin felt that the player may have suffered CTE (it is much more likely for a next of kin to reach out to have their loved ones brain studied if they believe they had an affliction, rather than if they had no symptoms).
Of that sample of 202 players at various levels of the sport, 110 of the 111 NFL players were diagnosed with CTE. That number drops down to 85% for collegiate/semi-professional/Canadian professional players and then drops off significantly for those players whose highest level of competition was high school at only 21% (3 of 14) and 0 of the 2 subjects whose highest level of completion was pre-high school. In addition, none of the high-school players showed signs of severe CTE, while just over half of the collegiate/semi-professional/Canadian players had severe CTE and 86% of the NFL players.
Former football player Jim McMahon describes his symptoms, which are similar to progressing CTE symptoms -
That Sounds Pretty Alarming, But Is It?
Due to the bias in the selection criteria for this study, the only definitive conclusion that could be drawn by the authors was that of the convenience sample studied, a high portion of the samples had CTE.
This does not tell us much, this is the equivalent of saying that people who were thought by their family to have CTE likely have CTE. Again this study does not say anything about the overall rate of CTE in football players (as most players do not go on to play professional or even college football) and only people who are likely to have a disease would usually provide their loved ones brain to a brain bank without incentive.
In addition, the National Institute of Neurological Disorders and Stroke in 2015 just began to create guidelines for diagnosing CTE. However, at the meeting they indicated more discussion needed to occur to validate the criteria with larger sample groups and more professional opinions. Therefore, there is currently no standardized criteria for CTE that is fully accepted. So the diagnosis decision for CTE in this study was still somewhat subjective.
In addition, the study noted does not determine the cause of CTE in the CTE positive subjects. It cannot be determined based on this study whether the trauma itself or trauma in combination with genetic/environmental factors caused the CTE or even if trauma was the causation at all.
So What Should I Take Away from this Study?
While the above study certainly does have its weaknesses, it also does show that at least some football players are experiencing cognitive issues. Does this mean it relates to football hits? Not necessarily. There are a variety of factors yet to be fully studied in relation to whether or CTE is truly its own cognitive disorder, whether symptoms are occurring due to issues such as lifespan, genetics, socio-economic factors, etc. Remember, correlation is not causation, and the study noted above at most, if not all studies you will read in the media right now are using hand-picked samples which are likely significantly overinflating the prevalence of CTE in football.
With more research a fuller understanding of CTE, its prevalence, causes, and hopefully cure will come out. But in the meantime certainly protect yourself and/or child from unnecessary excessive contact to the head, but also don’t put yourself or your child in a bubble until more search has been done!