Hometown U: UAA mouth guard may provide insight into concussions

February 9, 2013 

A shadow darkened Super Bowl Sunday last weekend -- the growing evidence of brain damage from professional football.

High-profile cases get headlines. Super Bowl champ Dave Duerson shot himself in the chest two years ago at age 50, asking that his brain be donated to science to determine what an NFL career did to it.

Anchorage has had its own headline. In 2010, a flag football player suffered a severe concussion after she ran into a pillar. After months of rehabilitation, she asked to address a local coaches' clinic on the hazards of head injury.

"There's just not enough information on (the brain)," Lexi Stewart told the Daily News. "The doctor we saw didn't know. The emergency room didn't know. How's a coach supposed to know? How's a parent supposed to know?"

Lexi Stewart is right. While there are plenty of statistics about emergency room visits from sports- and recreation-related brain injury among children and adolescents (almost 175,000 annually, up 60 percent over the past decade), there is very little information about what actually happens to the brain when it takes a hit.

The tools to measure that impact simply don't exist. With pressure coming from both professional and amateur sports, as well as the injuries of soldiers exposed to explosive devices in the Middle East, the rush is on to close this information gap.

Scientists talk about these impacts to the head as "accelerations." They can be linear (back and forth, up and down) or angular (spinning, as when the head whips back and the chin comes up.)

Some testing has been done measuring impact on helmets covering the skull. Another approach is to measure impacts to the upper jaw, which attaches directly to the skull.

Three engineers at the UAA, Anthony Paris, Jennifer Brock and John Lund, along with several undergraduates, are working hard to develop a mouth guard with sophisticated instruments for measuring these forces. The university has a patent pending on an oral bridge with six tiny accelerometer chips to measure impact to the head. The bridge is embedded in an acrylic mouth guard molded to snugly fit a wearer's teeth and gums.

Their challenge is to get accurate measurements, wirelessly transmit the data and develop useful information about brain injury from it.

"If a kid skateboarding in the street hits his head on the curb, how do you know what happened? How do you treat him?" Paris asks.

If that skateboarder were wearing an instrumented mouth guard, an EMT could download the data on the way to the hospital. Over time doctors would develop a database for effective treatment of head trauma.

Paris' first prototype, dating back to about 2004, was a simple model with a single chip embedded in a blob of acrylic -- primitive but capable of gathering data.

Next, the team found off-the-shelf sensors developed for detecting unwanted vibration in rotating machinery -- a possible warning that a bearing was going. They stuck three of these, each about the size of a sugar cube, onto a mouth guard. Recording and transmitting equipment were embedded too.

The result looked a little like someone who'd shoved too many hot dogs into his mouth. Still, they were able to use that version for early testing. Employing a local high school athlete, they gathered information and high-speed video as she "headed" soccer balls.

"We got beautiful data," Paris said, "data that no one has ever seen before."

While the engineering worked, the design needed innovation, so the tinkering continued.

Lund, an electrical engineer, replaced the chunky "sugar cubes" with his own tiny integrated circuit boards. The number of sensors dropped from nine (three in each cube) to six after they realized careful placement netted the same quality data. Lund soldered the chips side by side horizontally instead of vertically, lessening the mouth guard's height for an easier fit.

Their data began to illuminate impacts to the brain. Engineers measure linear acceleration in G's (acceleration triggered by gravity) and angular acceleration in radians per second squared. Gravity causes a free-falling object to drop at 1G, while a record turntable accelerates at 3.49 radians per second squared.

Now consider a soccer ball moving at 27 miles an hour hitting a player's head. The mouth guard measured linear accelerations at about 28 G's and angular accelerations of 3,900 radians per second squared.

The same test measured a maximum force at impact of 236 pounds lasting 15 milliseconds -- a large force for a short duration.

"Is that important?" asks Paris. "No one knows. No one has done the work."

Now polishing their fifth prototype with yet another still-secret innovation in mind, the team is growing confident that a quip John Lund made one day will indeed come true:

"In 20 years, no one's going to be putting a 'dumb' piece of plastic in their mouth."


Kathleen McCoy is an electronic media specialist at UAA, where she highlights campus life through social and online media.

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