December 5, 2021

I, Science

The science magazine of Imperial College

Iona Twaddell investigates chronic traumatic encephalopathy in sport
treatment shutterstock_147285710
Ireland captain Brian O’Driscoll being treated during the RBS 6 Nations rugby union match between England and Ireland in February 2010

You’re running down the field, shedding defenders left and right, ten metres to the line, five metres, three metres, within touching distance of a glorious try. Suddenly, out of nowhere someone the weight of a small boulder barrels into you, knocking you to the ground. The world goes black for a split second, but you get straight back up. You can’t see properly for the rest of the match, but that’s just part of the game, right?

Fast-forward thirty years and you’re listening to the neurologist telling you that your symptoms of confusion, altered mood and memory loss look like a type of dementia doctors are just starting to understand – did you ever play contact sports when you were younger?

For years, scientists have known that footballers and rugby players seem to have unusually high rates of dementia, but they’ve always assumed this is a form of Alzheimer’s disease. Actually, the players may be suffering from chronic traumatic encephalopathy (CTE), a dementia caused by head injury. Previously, doctors thought CTE was limited to boxers, but it has since been found in American footballers, ice hockey players and now in a rugby player.

This latest CTE victim was an amateur rugby union player, described in a recent paper from the Quarterly Journal of Medicine. As Dr Willie Stewart, one of the authors of this study and consultant neurologist at Southern General Hospital in Glasgow says, “It’s the exposure to brain injury that’s the risk factor here, not the sport… there is no reason why a rugby player should not get it… or a footballer.” This is a sobering thought as England prepares to host this year’s Rugby World Cup.

Neurons grown in tissue culture, with MAP tau protein stained in red and yellow

Of course, this study only concerns one case of CTE and we don’t actually know how widespread the disease is, because it is so often misdiagnosed. In fact, CTE can only be conclusively diagnosed once the patient is dead. Their brains bear the scars of past impacts: the septum pellucidum, an internal membrane separating the brain’s fluid-filled compartments, is shredded into silky filaments and there is a build-up of tau protein, appearing under a microscope like patchy brown mould on the brain tissue, clogging up the neuronal signals.

But whether CTE is widespread in rugby or not, any player knows that concussion (or mild traumatic brain injury) certainly is. There were 10.5 concussions per 1,000 hours played in English Premiership rugby in 2013-2014. And players often brush it off, a concern for Richard Morris from the brain injury charity, Headway, who says that it’s “ingrained in the culture, that you get a knock and you carry on”. This can worsen the injury, increasing the risk of longer-term impacts like CTE, which “a lot of people still aren’t thinking about”. Rugby is making some progress in shaking this dangerous attitude with comprehensive guidelines for pitch-side concussion assessment from World Rugby. Whether this will have a large effect or not, rugby is certainly ahead of other sports such as football where there are limited, if any, concussion guidelines.

The risk of CTE or other long-term impacts is enough of a concern to worry sports federations across the Atlantic: the NFL has paid out $765 million to compensate their players who have had head injuries from the sport. If rugby doesn’t get its act together, it might be facing similar consequences. As Dr Stewart says, “there’s a lot that can be done in sports like rugby and football to try and reduce risk of brain injury before we get to a point where we just have to say it’s an acceptable feature of the game.” Greater understanding of CTE and management of head injuries will hopefully mean that the devastating tackle that robbed you of a glorious try doesn’t become the devastating dementia that kills you.

Iona Twaddell is studying for an MSc in Science Communication

Images: Featured image, Jonny Wilkinson (Shutterstock);  Brian O’Driscoll receiving treatment (Shutterstock); Tau protein-stained neuronal cell culture (Wikimedia Commons)

Citation: Stewart, W. et al. (2015) Chronic traumatic encephalopathy: a potential late and under recognized consequence of rugby union? QJM: An International Journal of Medicine, 2015, 1–5. DOI: