University athletes with concussions still show changes in the brain after medical clearance to play

University athletes who are given medical clearance to return to play after a recent concussion still have changes in their brain structure and function, a new Canadian study has found.

According to researchers at St. Michael’s Hospital and the MacIntosh Sport Medicine Clinic at the University of Toronto, both male and female athletes experience these changes in the brain, which persist even after other symptoms have disappeared.

READ MORE: Contact sports can alter the brains of even young, healthy athletes: study

“What this study tells us is that there’s a bit more going on under the hood than we can see just by looking at preventable symptoms and a ‘pen and paper’ test of how athletes are performing,” Dr. Nathan Churchill, the study’s lead author and a post-doctoral fellow at St. Michael’s Neuroscience Research Program. “What we found was that there was evidence that things are affected during early concussion are still present at the time of medical clearance.”

To see if there were changes present in the brain that typical outside testing could not see, Churchill and his team looked at 27 male and female athletes who had recently been diagnosed with a concussion, as well as 27 uninjured varsity athletes, in seven different contact and non-contact sports.

The team used advanced MRI to measure the injured athletes’ brain structure and function a week after a concussion was diagnosed, and again after they were medically cleared to play again. They then compared the results to the uninjured athletes.

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What researchers found was that there were differences in the structure of the brain’s white matter – the fibre tracts that allow different parts of the brain to communicate with each other.

They also found differences in the brain activity, especially with the areas associated with vision and planning. The athletes that took longer to recover also showed changes in the areas of the brain associated with bodily movement.

This, Churchill says, is the first concrete evidence that concussed brains lag behind when it comes to recovery. It also shows that the concussion may also outlast any present symptoms that doctors typically look for when they decided to return an athlete to the game.

Those differences that are seen in the brain at medical clearance are particularly concerning because vision, planning and physical co-ordination are important for athletes to avoid re-injury, Churchill speculates.

“This raises the question about what’s going on in the brain and does it warrant further investigation,” Churchill says. “By all measures, people seem to be doing quite well at the time that they’re clear. I mean, they have to be to return. But there’s something going on in the brain and we think this does warrant further investigation because we need to understand why that’s happening. Does the brain actually return to normal, stay the way it is or is this just the new normal for these athletes?”

READ MORE: New concussion protocol advises against long periods of rest

Churchill hopes to follow up with the study’s participants long term to find this out.

The study was published Thursday in the journal Scientific Reports. 

In July, Parachute Canada, launched the first guidelines in Canada, it recommends protocols be followed in order for physicians to medically clear any athlete to play again.

A thorough history and physical examination and some physical and cognitive testing take place, as well as details of the injury – what happened, how and when.

A typical return to play protocol is outlined as such:

• No activity, only complete rest.
• When symptoms are gone, the patient can do light aerobic exercise (like walking or stationary cycling), but no resistance or weight training.
• Start only with activities specific to the sport. For example, start with skating if the patient is a hockey player. No contact or risk of contact.
• Drills without body contact. The patient may add light resistance training and then progress to heavier weights.
• Participate in drills and body contact.
• Back to the game.

However, the athlete should only move on to the next step if they’re asymptomatic at the level they’re at.