CTE in a soccer player with no history of concussion

Football/Soccer/Scientist friends,

This is a landmark study (see Grinberg et al. (2016). It shows the confirmation of chronic traumatic encephalopathy (CTE) in the post-mortem brain of a soccer player WITHOUT any history of concussion. By the way, the player (though he isn't named) is almost certainly Hilderado Bellini - a legend of the game. Bellini won the world cup with Brazil and played for some of the premier Brazilian clubs of his time.

The no-history of concussion is important, b/c it supports the idea that subconcussive impacts in soccer may be sufficient to produce CTE. And, honestly, as an aficionado of the beautiful game, this is somewhat troubling.

Why is it troubling? Because for the longest time, I (and many) assumed that CTE would rear it's ugly head in the world of soccer, and while there have been some reports of possible CTE in soccer players (see Hales et al. (2014) , this is the first (to my knowledge) which highlights the history of no-concussion.

There are caveats to over-interpreting this study-

1. This gentleman was playing soccer in the 50s - a time where diagnosing concussions wasn't the norm. Therefore, it is entirely possible that he did experience concussions - but were never diagnosed.

2. This is one anecdotal report. It's possible that his CTE is independent of his history as a soccer player and that his CTE was consequential of some other genetic/environmental effect.

Why is this study relevant to soccer?
Subconcussive injuries are asymptomatic. Therefore, they pose a greater risk to athletes than concussions because they are impossible to diagnose. If the link between subconcussive injuries and soccer is confirmed, perhaps we need to have a serious discussion about heading.

Do we know for sure that heading leads to subconcussive injuries?
No, far from it. There's little evidence for it, except this one study that suggests that heading in amateur soccer players leads to abnormal white matter (the stuff that allows brain cells to send messages to each other) restructuring ( see Lipton et al. (2013)). But, this is far from confirmation of the above.

It is interesting to note that Bellini was a central defender - a position which involves the most heading in a game (I don't have data to support this, but, it would be fairly obvious to anyone that plays/watches soccer). Therefore, the repeated subconcussive injury issue is consistent with what we might expect.

As more and more soccer players donate their brains to science, I expect us to see an increase in CTE diagnosis. With the suicides of Robert Enke and Gary Speed - two well known, high profile, footballers, the interest in CTE was always going to rise.

I'm not sure what the long-term impact will be on soccer. But, we are at the beginning stages of raising awareness for what might be an insidious beast preying upon our beloved soccer-playing heroes.

Pubmed link: Link to original study

Heading in youth soccer: what the science says

Recently, the United States Soccer Federation (USSF) released a report advising the elimination of heading in soccer for kids under the age of 10. And recommends that full-contact heading not be allowed till athletes get to 16 years of age.

Now, while everyone is on board with the idea that player safety is very important, particularly that of children and young adults, there has been much debate over whether the guidelines would benefit athletes and soccer in the long-term.

Let me start by saying that I believe that concussions in soccer are a serious, serious, serious, serious, serious, serious, serious concern. Is that serious enough? I believe that concussions are currently being managed incorrectly by the Football Associations and FIFA. And that things need to change rapidly so that our soccer players can live a healthy life after they retire. However, today, we will be focusing on the topic of concussions in youth soccer players.

While one can have a myriad of personal opinions on this topic, and certainly, I do, too (I'll discuss those later), the majority of this post will look at what the scientific literature says re: Heading in youth soccer. I understand that many do not have access to the articles I'm citing here, so I will link to the abstract (which is available to all), and if you are interested in a particular article, tweet at me, and I'll send it to you.

1. Can heading the ball lead to concussions in high school players?

Yes. It isn't the most common form of concussive injury in youth soccer players, but, it is certainly possible (Cornstock et al, 2015 ). However, what this study does not look at  is HOW those ball-to-head related concussions were procured. That is a key caveat to this study.

There is another study that suggests that zero concussions were produced by heading the ball correctly, and all were a result of the ball striking an unprepared player at close distance (Boden, 1998) .

2. Can heading the ball lead to concussions in youth soccer players?

Doesn't seem like it. Here's a key excerpt from a book chapter  ---

"Dr. Kirkendall . . . calculated the impact of a soccer ball on the head of youths of various sizes, based on the likely speed of the ball, and concluded that the force of impact is well below the force that is thought to be necessary to cause a concussion in heading a soccer ball." --- Dr. Donald Kirkendall, Causes of head injuries in soccer .

Even in U14's soccer, there is likely not enough ball velocity to cause concussion (Hanlon and Bir, 2012) .

A meta-analysis (looking at various studies between athletes 10-24) suggested heading the ball was unlikely to cause injuries (Pickett et al., 2005).

Essentially, those kids do not kick the ball hard enough to cause the G-forces (acceleration forces) to result in concussive injuries.

3. What about subconcussive injuries from heading?

In order to answer this, a quick primer on subconcussive injuries: It is an emerging area of research that suggests that repeated impact to the brain can result in brain damage, even though concussion hasn't occurred. The problem with studying subconcussive injuries is - how do you tell if someone has one? Neuroscience tackles this in a couple of ways. Firstly, we have identified certain biomarkers (biological red flags) to suggest if someone is exhibiting hallmarks of disease. The second technique is to look at behavioral tests that suggest whether someone is cognitively impaired. The assumption being, in both cases, if subconcussive injuries have occurred, there will be a biological (biomarker) and/or behavioral (neurocognitive) change.

Coming back to the original question. Most literature suggests that heading the ball does NOT lead to changes in biomarkers/neurocognition. These can be found here --- Kontos et al. (2011), Stephens et al. (2005), Kaminski et al. (2007), Broglio et al. (2004), Guskiewicz et al. (2002) and others.

But, this study, does suggest that a cognitive change may occur - Zhang et al. (2013) . I have to state a caveat - this Zhang study is poor. The effect size (how different the soccer-playing and non-soccer-playing groups were from each other) is very small. For my science friends - they set a non-one sided gaussian t-test alpha of 0.1, which is an immediate red flag. For my non-science friends - I think the effect they observe is not worth believing.

4. Okay, that's a lot of words. What's the gist?

Currently, a preponderance of the literature does not support the idea that heading the ball leads to subconcussive injuries in youth (kids - high school) soccer players.

5. Is that a definitive no then?

Not quite. You see, the work surround subconcussive injuries is nascent. And, as such, has caveats. For example, some of the behavioral tests and biomarker tests need further validation. Therefore, it is theoretically possible that subconcussive injuries ARE occurring, but our tests aren't well enough designed to detect them... just yet.

6. What about the report of the kid who almost died after heading the ball?

That's a real report. That happened a few years ago, and no one has contradicted the young man's claim that his subdural hematoma (potentially fatal bleed in the brain) was the result of a single header (Lutfi et al., 2009). My concern is that the report says he headed the goalkick with the "front" of his head. I am not sure if this means with his forehead (which would be the correct way to head the ball), or with the top of the head (incorrect, and unfortunately seen in young soccer players who haven't practiced heading).

7. What about player to player contact?

Yes, this often is the culprit for concussions. Most of the articles I've linked to above suggests the same. These injuries can be a result of two players going for a header, or accidental contact with one player's knee, while the other is on the ground, etc. There are a myriad of ways that player to player contact can result in head injury and concussion.

Head to head injury is a serious concern

Okay, now we are going away from the realm of scientific literature into my own opinion (using the literature I've read as a basis, of course)

8. So, what's the solution?

In my opinion, there should be a serious punishment for serious player to player contact. In the last 3-4 years, the concept of "out of control" tackling has come into play.

You see, while I was growing up, the definition of a good tackle was "getting the ball". If a player got the ball before he made contact with the player, it was deemed a good tackle - regardless of whether this involved excessive force or injury to the opposing player. However, now, even if a player wins the ball, if he comes in with excessive force, tackles from behind or uses two-feet, the referee usually punishes the tackler with a red card (FIFA, law 12) . Why? Because all of those conditions are optimal for causing injury.

Similarly, excessive force, using elbows, out of control contact with an opposing player's head (knee-head, for example) should be deemed dangerous play, and therefore a red card. This would result in players being careful of so-called 50-50 balls, and wary of using their elbows as leverage.

9. But, what about heading itself?

I respect people's opinion who think "well, removing heading in youth players won't hurt". But, in my opinion, having young kids learn how to head the ball early would lead to developing the appropriate neck muscles needed (Gutierrez et al., 2014) to prevent head injury in the future. If heading the ball isn't being introduced to them until they are 14, this may lead to an INCREASE in the number of concussions. Because, by the time they're 14, they are kicking the ball much harder, and have yet to learn the basics of heading.

Incorrect way to head the ball. (Image via http://hubpages.com/sports/Soccer-Head-Injuries-in-Children-Brain-Damage-from-Heading)

10. To summarize:

1. Preponderance of scientific literature does not support the idea that heading can lead to concussions or subconcussive injuries in soccer players.
2. More work needs to be done.
3. In order to minimize concussion, new rules regarding player contact need to be made.