How are concussions diagnosed and measured?
Concussions, also known as mild traumatic brain injuries, are typically diagnosed based on the symptoms that show up within minutes to hours after the injury and the severity of those symptoms, including:
- Headache
- Balance problems
- Sensitivity to light and sound
- Disorientation
- A feeling like being in a fog
- Emotional changes, such as irritability
- And in more severe cases: nausea, tunnel vision and loss of consciousness lasting under 30 minutes.
Traumatic brain injury severity is measured using scales, such as the Glasgow Coma Scale. Other assessments, such as the Concussion Recognition Tool – help non-medically trained people to identify and manage concussions to help determine whether or not to remove an athlete from play.
Why is it important to study the effects of concussions on younger athletes?
They are vulnerable to concussions in two ways. First, their brains are developing, so their physiology is going to respond to a concussion differently. Missing time from school or their activities due to a concussion will also have a negative impact on their mental and physical health. Second, they are a more vulnerable population and may be less likely to advocate for themselves and what they need to recover.
Why do researchers make the distinction “sports-related” concussions?
These are caused during a sport or a sport-related activity, rather than something like a fall or a car accident – which are other common causes of mild traumatic brain injury or concussion.
There are a few reasons to make the distinction:
- It's one of the most common causes of concussion in youth and young adults.
- They can be a unique type of injury, especially when we talk about repeated sub-concussive injuries.
- Findings about sports-related concussions go back into the sports themselves to create better safety guidelines.
These distinctions are why we need to have studies that specifically look at this unique population within sports.
What is the hardest part about studying concussions, especially with sports-related concussions?
It’s complex and nuanced because a lot of the symptoms of concussion are not specific to concussions. There’s a range in severity of symptoms and duration – and we’re still figuring out why that is.
Furthermore, there’s pressure on athletes to perform, and studies have reported there is a tendency to underreport symptoms.
You used something called the Automated Neuropsychological Assessment Metrics in the study. Can you explain what it is?
It’s a battery of several different tests that measure a range of cognitive skills – reaction time, inhibition, visual-spatial skills, memory, attention and more. It’s also flexible to administer, because you can do it on a tablet in training rooms.
For the simple reaction time test, you click or press a button every time an image appears on the screen, usually an asterisk or something similar. The amount of time between each image appearing is randomized.
Why is studying reaction times important?
Reaction time is really one of the most basic motor functions or cognitive functions that we have, so it's really important for the foundation for a lot of other skills. For athletes especially, even slightly slower reaction times can make a really big difference on the field where there's a lot of decisions to make very quickly.
Decreased reaction times can lead to an increased risk for injury, either another concussion or some kind of musculoskeletal injury. So even the small differences can make a big impact.
Post-concussion, how long does it take for reaction times to reset back to that baseline?
It varies by person. I would say normally between two to four weeks you'd expect, just in general, symptoms and the performance to be back at baseline. But it’s important to have athletes do a baseline test at the beginning of the season, so then they can compare their performance after concussion.
On a physiological level, why are concussions impacting reaction times?
I think it's something we're still investigating, but we have a pretty good idea. One reason is that the brain will swell after the injury, so there's inflammation. That inflammation can just cause delayed thinking in general, slower reaction times.
And then in recent studies, there's a lot more evidence showing that the movement of the brain in the skull during a concussion can cause the axons of the neurons to stretch or tear. If they are broken like that, it can slow down reaction and processing times.
You did a study on reaction times among high school athletes with and without a history of concussion. What did you find?
We found that those athletes who had had multiple past concussions – reported having two or more concussions in their life – it seemed like they were less likely to be able to sustain their performance over time, and, for some, their reaction times slowed to a noticeable degree.
And comparatively, those who only had one or no concussions were less likely to lose their performance and able to keep up their reaction time speed.
This test was mostly conducted with football players, so we need to look at expanding this line of research to bigger sample sizes and more complex situations – such as other cognitive tasks that mimic the sport being played. I also think we need some neuroimaging studies to understand what's happening in the brain when we're seeing these differences in behavior.
You also studied sex differences and concussion injuries in high school and collegiate athletes. What were the findings?
We did find some evidence around inhibition.
In females with a history of concussion, there was more likely to be increased inhibition. On the other hand, males with a history of concussion were more likely to have decreased inhibition.
In other words, males with a history of concussion were more likely to take risks. Some prior studies have found that women athletes may be more likely to have kinesiophobia – fear of movement – post-concussion. There’s a fear of re-injury. That’s may be why we are seeing that increase in inhibition. We’ll need more data, but it’s an interesting trend.
Additionally, there’s some evidence that females take longer to recover from a concussion. In fact, female athletes in our study reported longer recovery times following their most recent concussion compared to male athletes.
As someone who's studied the brain and the impacts that these injuries have on the brain, do you have any advice or things that you would say to parents or coaches to help them around this topic of concussions?
I think we’re moving in a good direction overall. The past decade has seen increased awareness and understanding around concussions and recovery.
For parents, I’d recommend they check out the HEADS UP training and information. These are part of the guidelines for college athletics, but these free resources are great for parents, coaches or anyone working with young athletes.
As long as we keep those around a sports team educated and aware of concussion research, I think we’ll do a better job protecting young people’s brains and health.
Ultimately, we’ll do the most good if we can keep building collaborative relationships between researchers and athletes, trainers and coaches to gain more insight into concussions.
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