Most of us wear bike helmets with the expectation that they are protecting one of our most valuable assets: the brain. However, this may not be the case, according to scientists who study the effects of an impact on the brain. Bike helmets don’t protect at all against a certain form of concussion that’s likely to occur in the event of an accident involving trauma to the head.
This type of concussion is known as a “linear acceleration.” It happens when the brain moves in the direction of an impact. Literally, your brain rattles around inside your skull, moving forward or back or to either side. It used to be that our understanding of concussions centered around the skull impacting with an outside force (like the pavement, in the case of a cyclist). However, research done over the past few years has shown that many concussion symptoms are also caused by the brain colliding with its own skull.
The reason why bike helmets are not effective at protecting your brain from a crash is because they were first designed when we didn’t understand much about concussions. They are made to protect against head injuries such as fractures to the skull, lacerations, and brain contusions. A brain contusion is, in simple terms, a bruise of the brain tissue. During an impact, small blood vessels leak. These “brain bruises” are far more serious than a bruise that you might get on your arm, however. Contusions in the brain mean that your brain has sustained some damage. This damage can be serious or mild, depending on the impact. Usually, contusions tend to show up in parts of the brain that are near sharp ridges on the inside of the skull. Bike helmets are meant to protect against contusions and to prevent the serious side effects of this type of injury.
Now that the knowledge about the nature of concussions has expanded, bike helmets need to be redesigned to protect against linear acceleration and other forms of brain movement during an impact. Movement of the brain inside the skull can cause damage to brain cells and trigger the ongoing symptoms of concussion. Brain communication pathways may be disrupted and a person can experience headaches, nausea, poor concentration, and irritability.
Bike helmet designers are now looking at ways to reduce rotational acceleration of the brain and absorb the impact of the brain inside the skull. Scientists warn that these new concussion-preventing helmets will cost more but when it comes to protecting the brain, it should be worth the price-tag.
Cyclists are not the only ones misguided about how well their helmets are protecting their brain. Football helmets were recently profiled in a study by U.S. researchers. There was a problem, however, in trying to figure out the effectiveness of football helmets in absorbing rotational acceleration of the brain—there were no measuring tools available. The researchers decided to develop their own protocol for measuring the effectiveness of a helmet to protect against concussion. These tools will help scientists develop better helmets in the near future.
This is not to say you shouldn’t bother to wear a bicycle helmet right now. Research shows that bike helmets still reduce the risk for suffering a skull fracture. Continue to put that bike helmet on before you hit the streets, but it’s time for them to be updated to our new understanding of brain injuries.
Source(s) for Today’s Article:
Schwartz, D., et al., “Bike helmets should address concussion risk, scientists say,” CBC News web site; July 3, 2013; http://www.cbc.ca/news/health/story/2013/07/02/f-bicycle-helmet-concussion.html, last accessed Aug. 28, 2013.
Post, A., et al., “A centric/non-centric impact protocol and finite element model methodology for the evaluation of American football helmets to evaluate risk of concussion,” Comput Methods Biomech Biomed Engin. March 12, 2013.
Bergenstal, J., et al., “Pediatric bicycle injury prevention and the effect of helmet use: the West Virginia experience,” W V Med J. May-June 2012; 108(3): 78-81.