High-tech bike helmet is like an air bag for your brain
Think about concussions and there’s a good chance football comes to mind. So you may be surprised to hear that bicycling – not football – is actually the leading cause of sports and activity-related concussions and brain injuries in the United States.
In order to protect bikers from serious head injury, a Stanford lab is working on an entirely new type of helmet that inflates to cushion a biker’s head from hitting the pavement.
David Camarillo, an assistant professor of bioengineering at Stanford, developed the idea after suffering two concussions from bike accidents in the past.
What makes his system different? Well, it’s not a traditional helmet at all. Instead of strapping it atop your skull, t comes in a “pocket” that is worn around the biker’s neck. In the event of a collision, it pops up and expands – much like an air bag in a car – to surround and protect the head.
“Foam bike helmets can and have been proven to reduce the likelihood of skull fracture and other, more severe brain injury,” Camarillo said in a press release. “But, I think many falsely believe that a bike helmet is there to protect against a concussion. That’s not true.”
The results of his lab’s latest tests of the device are published in the journal Annals of Biomedical Engineering.
“We conducted drop tests, which are typical federal tests to assess bicycle helmets, and we found that air bag helmets, with the right initial pressure, can reduce head accelerations five to six times compared to a traditional bicycle helmet,” said Mehmet Kurt, a postdoctoral scholar in Camarillo’s lab.
To test the system’s effectiveness, Camarillo and his team put the protective gear on a dummy head that carried an accelerometer, which measures acceleration rates, and then dropped the fake head from differing heights. The head was tilted at two distinct angles to approximate collisions with both the side and crown of a human head. The helmet was dropped from as low as 0.8 meters (about two and a half feet), up to a height of two meters (about six and a half feet) off the ground. The linear acceleration of the helmet was measured once it slammed to the ground.
Once expanded, these air bag helmets are larger than the typical foam-padded bike helmets, which makes for softer, better-cushioned headgear. The bags were pre-inflated during the drop tests.
“As our paper suggests, although air bag helmets have the potential to reduce the acceleration levels that you experience during a bicycle accident, it also suggests that the initial pressure that your air bag helmet has is very critical in reducing these acceleration levels,” Kurt said.
The design is still being tweaked. If the helmet wasn’t inflated with the maximum amount of air it could possibly bottom out, which would lead the head to smash to the ground at a higher force than with a traditional bike helmet. Right now, the current air bag helmet’s inflation is triggered by a chemical process that doesn’t ensure maximum air pressure, so more work needs to be done on that aspect.
The drop test that the team performed is the industry standard for bike helmets, Camarillo added.
While the helmet is currently being sold in some European markets, it is not yet available in the United States.
“If our research and that of others begins to provide more and more evidence that this air bag approach might be significantly more effective, there will be some major challenges in the U.S. to legally have a device available to the public,” Camarillo asserted.
In order for that to happen, this study suggests that some changes will need to be made in how helmets are tested in general. For instance, helmets are traditionally tested on dummies without a neck, which wouldn’t be able to wear Camarillo’s design to begin with.
What’s next for Camarillo’s research? The lab plans to test the helmet to see how it affects rotational acceleration as well as forces on the head at impact. Camarillo and his team also want to look at how the helmet could lower tissue-level strains on the human brain.
