August 20, 2020, Kitchener, Ontario
Posted by: Robert Deutschmann, Personal Injury Lawyer
With a recent report from the University Health Network in Toronto releasing that nearly 160,000 people suffered concussion every year between 2008-2016 many concerns have been raised. The number is surprisingly high and is in part due to better diagnosis and awareness of the condition. Common sources of concussion include car accidents, bike accidents, sporting accidents, physical assaults, and slip and falls.
The same study found that children under 5 and women over 65 were most likely to experience a concussion, but that overall men had the highest rates of concussion. Rural residents were also far more likely to suffer concussion than their urban counterparts.
The American Academy of Neurology published an article in July considering the question of driving post concussion. The article “Should You Really Be Behind the Wheel After Concussion?” gives careful consideration to the complex demands that are placed on the brain by driving and whether/how long it takes the brain to regain these abilities.
Those who had concussion were slower to react to complex driving conditions such as a child chasing a ball onto the road, or a traffic light changing to red, and had longer reaction times and stopping distances compared to those people without concussion. Here is the interesting summary of the study.
If you have sustained a concussion you should avoid driving altogether until you are given medical clearance to do so.
"People who have concussions often have slower reaction times as a result, and do more poorly on tests of thinking skills after their injury than their peers without concussions," said Julianne D. Schmidt, Ph.D., ATC, of the University of Georgia in Athens. "Our study suggests that complicated driving skills, the kind involving split-second reaction times that could mean the difference between life and death, are the ones that may take the longest to regain after you have a concussion—even when all of your symptoms have resolved."
The study involved 28 college students with valid drivers' licenses and an average age of 20, including 14 with concussions and 14 without. Ten of the 14 concussed students experienced concussions while playing sports. All college students were matched by age, sex, and driving experience. Participants completed both a simulated driving reaction time test and a computerized neurocognitive test within 48 hours of their concussion symptoms resolving, which occurred an average of 16 days after the injury.
The driving reaction time test consisted of two simulated driving scenarios. The first scenario involved a stoplight reaction time simulation in which the stoplight changed from green to yellow and participants had to rapidly choose to brake or accelerate. The second scenario involved a child running in front of a vehicle and participants needed to brake or swerve to avoid collision.
The computerized test consisted of four measures of reaction time including simple, complex, and Stroop reaction time, which is the lag that occurs when you are asked to select a word like "blue" that is printed in a different color.
The drivers who had concussions demonstrated slower computerized complex reaction times than those who did not have concussions by an average of 0.06 seconds. When reacting to a change in stoplight color, it took those with concussions 0.24 seconds longer to react, or the equivalent of 15.6 feet in stopping distance, compared to those without concussions.
During the driving simulation involving a child running in front of a car, it took those with concussions 0.06 seconds longer to react, or the equivalent of 3.3 feet in stopping distance, compared to those without concussions. Slower reaction time is a strong predictor of crash risk, and these additional split seconds and feet needed to change the vehicle's movement could be critical for avoiding an accident. Interestingly, only the computerized complex and Stroop reaction times moderately related to the driving stoplight reaction time, and no other relationships were observed, suggesting computerized reaction time measures are not a perfect replacement for measuring real-life driving reaction times.
"Overall, after the symptoms of the drivers with concussions resolved, their reaction times were similar to drivers who didn't have concussions. However, when we looked specifically at stoplight reaction time, we saw lingering deficits in the drivers who had concussions," Schmidt said. "This could mean traditional reaction time tests aren't the best measure of driving responsiveness and readiness. And that could have important public safety implications, considering more than three million people have sports-related concussions in the United States each year."