Dal study of football players sheds light on how concussions affect the brain

Neuroscience researchers at Dalhousie University are investigating how head impacts lead to injuries in football players.

One of their preliminary findings is that it isn't the intensity of a single hit that can lead to concussions or trauma-like symptoms, it's the accumulation of small hits suffered during practice or games, said Alon Friedman, a co-author on their recently published study.

"It's not necessary that we have to treat a concussion itself," he said. "The concussion is an outcome of many, many small injuries that you had throughout the season and you didn't even feel about them."

Their findings lend support to the idea that head impacts can cause dysfunction in the blood-brain barrier, which helps shield the brain from salts, proteins and toxins in the blood. When it's impacted, leakage can occur, causing changes in the brain function and structure, which can result in cognitive decline or emotional and movement problems.

Friedman said the effects of the leakage depend on what part of a player's head is impacted, since the brain has various networks of nerve cells that control things like behaviour, mood and movement.

One of Friedman's co-authors is Casey Jones, a former Dalhousie Tiger football player and coach, and the current resident physician in the university's department of emergency medicine. 

"My goals as a past athlete and coach and someone who's been really involved with football my whole life is, 'how can we make our game safer?'" Jones said. "What are aspects of our game that we can, you know, reduce impacts to the head?"

Previous research on deceased athletes with a history of chronic traumatic encephalopathy, a brain disorder caused by repeated head trauma, has found evidence of changes in the blood-brain barrier, Jones said.

"Not everyone after a concussion will have problems in the future, actually most people, most individuals after concussion will heal and will be fine," Friedman said.

But in some cases, people are susceptible mild head injuries, he said, and it's important to identify those who are at risk and who could develop complications in the future, Friedman said. 

Their study, which was led by researchers at Dalhousie and published in January in the Clinical Journal of Sport Medicine, involved 60 football players. Eight had suffered a clinically diagnosed concussion, and five of them underwent an assessment to gage leakage in the blood-brain barrier. 

High-tech helmets

They used Riddell SpeedFlex helmets that are equipped with sensors to measure head impacts and detect concussions.

One of the benefits of using the helmets, Jones said, is that they can continue to provide data days after an impact, showing any lingering effects.

Friedman said a previous study on traumatic brain injuries, conducted in collaboration with the University of Pennsylvania, found that 60 per cent of cases with blood-brain-barrier dysfunction had healed three months later. The remaining cases had not and were likely to worsen, he said.

Although the current study is a pilot project, Jones is optimistic that their work will continue, although access to funding, technology and players are challenges.

Friedman said their findings suggest it's important to identify players who are susceptible to mild head injuries and risk developing complications in future. 

"If we can identify them early, then we can treat them before they develop the severe complications."