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A new generation of hard hats promises better protection against workplace concussions, also known as mild traumatic brain injuries.
These hard hats incorporate technology that not only protects the head from direct impact, but also from an oblique blow that causes the head to suddenly spin – a major cause of concussions.
“The human brain is easily injured by rotational force,” says Michael Bottlang, director of the Legacy Biomechanics Lab in Portland, Ore. For example, he says, a boxer will “drop like a fly” from a head-spinning punch to the chin.
So Bottlang and Dr. Steven Madey, an orthopedic surgeon in Portland, developed a helmet to absorb rotational force. It’s made and sold by WaveCel, a company the two men founded to make safer bike helmets.
The WaveCel helmet is just the latest effort to update products, known as industrial hard hats, which brain injury experts say are overdue for an upgrade.
“Unfortunately, today’s most widely used hard hats look identical to those from the 60s,” says Bottlang.
MIPS, a Swedish company, offers competing technology to protect a worker’s brain from sudden rotation.
Improved headsets like these “keep the brain more stationary, and that has a lot of potential benefits,” says Dr. Brandon Lucke-Wold, a neurosurgeon at the University of Florida who has no connection to the medical industry. helmet.
Understanding concussions in the workplace
About a quarter of all concussions in adults occur at work, particularly on construction sites. Falls, which often cause the head to suddenly turn or tilt, are the most common cause.
One of the reasons workplace brain injuries are so common is that hard hats, unlike sports helmets, haven’t changed much since their invention a century ago.
Lucke-Wold, who often treats patients with brain injuries, wears a state-of-the-art bicycle helmet on his daily commute.
“But the construction workers I saw cycling home today were wearing hard hats very similar to those I saw 10 or 15 years ago,” he says.
A typical safety helmet consists of a plastic outer shell with an internal webbing suspension system. Some models include foam padding on the sides and a chin bar.
This design is effective in protecting the brain from direct blows, such as a hammer dropped by a double-decker worker. But traditional hard hats aren’t as good when the impact happens at an angle.
Studies show this is because an oblique impact can cause the helmet and the head inside to spin suddenly and violently. And a growing body of research shows that the brain is very vulnerable to this type of rotational force.
The reason for this is that the brain looks a bit like an egg yolk – a soft capsule surrounded by liquid and contained inside a hard shell.
You can shake an egg forcefully without disturbing its contents. But experiments show that if you spin one hard enough, the yoke inside will break even if the shell remains intact.
Most helmets act like an eggshell.
“They do a job of reducing strength, so they serve a purpose,” Madey says. “But if they’re not optimized to decrease rotation, they’re not optimized to prevent injury.”
A helmet that works like sand
Madey and Bottlang originally founded WaveCel to make better sports headphones.
Their inspiration came from observing what happens to a ball when it hits the ground at an angle, as a biker’s head often does in a crash.
The ball doesn’t just bounce, Madey says. “It will touch the ground, there will be friction and it will create rotation.”
Unless the ground is made of sand.
“If you throw a ball into a sandbox, the sand gives way underneath, it doesn’t spin the ball,” Madey says. And the ball does not bounce.
Madey and Bottlang therefore developed a helmet liner made from a special plastic honeycomb designed to act like sand.
“The honeycomb structure is a very light and breathable material that is not only good at absorbing linear force, but also at breaking that spins like sand would,” Madey explains.
The WaveCel liner can be found in several sport helmets from major brands.
An independent study found that bike helmets with WaveCel or MIPS technology were better than conventional helmets at reducing rotational force. A study conducted by Bottlang and Madey found that WaveCel outperformed MIPS for the type of head impacts caused by falls.
Price is a potential barrier to widespread acceptance of new helmets.
WaveCel helmets cost between $169 and $189, several times the amount of a standard helmet and more than many high-end models, including some with MIPS technology.
“If I have a goal in the next few years, it’s to bring prices down,” says Bottlang.
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