Getting a better fix on head injuries with a "smart" mouthguard

Paris with undergraduate research assistant Grant Birmingham.

When I tracked down mechanical engineer Anthony Paris in late May to catch up on an engineering INNOVATE project, we quickly migrated from his office over to a nearby conference room. The whiteboard there was covered with a lacy blue scrawl, an eruption of calculations that drew the eye and held it. But we didn’t talk about those at first. 

Instead, every few minutes he’d dash back to his office and return with something mechanical: a curved spine with an embedded rod on the side to reinforce it; two big white plastic blocks attached to one another by curved rods, simulating the lumbar spine attached to the pelvis; or a mouthpiece with three sugar cube-sized attachments that looked like something a dentist might try and shove into an unwilling mouth.

His current INNOVATE award will further research on the instrumented mouthguard. The funding bought him two portable force plates to continue testing the latest-generation device.

Paris is quick to point out that credit for his recent successes is shared with his INNOVATE Co-PIs, engineering professors John Lund and Jennifer Brock. Lund engineered the electronics and Brock wrote proposals and synthesized data, including high-speed video analysis.

First UAA iteration of a "smart" mouthguard.

A process of constant refinement

On the first iteration created at UAA, the team used an 18-year-old veteran soccer player to head balls with the mouthguard in place, recording impact to skull. ME undergraduate Tessa Kara was funded through the Office of Undergraduate Research and Scholarship (OURS) for this first round of testing.

Now, with a more compact second generation mouthpiece — the wireless transmitter and data logger are separate from the mouthpiece, so it’s slim and more compact — he’s just finished a round of testing with another subject, this time a young man. Over the course of two sessions, the test subject headed soccer balls 10 times at five different velocities, ranging from 8 to 28 miles per hour.

The testing went well. “We got great data!” Paris said, sounding both excited and relieved. “The device worked flawlessly."

Birmingham with the slimmer second-gen model.

The next step comes this summer, when he’ll position a third tester on the portable force plates so that when he maneuvers to head the ball, the force plates will also be gathering data on the interaction between the body and the ground. He’ll then have a complete loop, soccer ball to head, feet to floor.

The force plates echo earlier work with a biomedical team in Boise, Idaho on the biomechanics of soccer heading. There, a single force plate was permanently installed in a gym floor, and Paris dropped a soccer ball 35 feet onto a bowling ball positioned on the force plate, the curves of which duplicated those of the human head and simulated the impact between ball and head.

Increasing concern over concussive head injuries

All this effort is in service of getting detailed and accurate measurement of impact on the human skull. There is much public debate about appropriate treatment for sports concussions, from The New York Times topics page on football and head injuries to a story this April in the Anchorage Daily News about a local teen who experienced a serious concussion during an indoor flag football practice. New York University even hosted a debate earlier this month on banning college football due to head injuries.

For Paris, the cause of impact is less important than accurately measuring the accelerations of the head due to impact. In fact, improvised explosive devices (IEDs) deployed against soldiers in war are another critical application.

“Do accelerations of the head determine the type of brain injury someone has,” he asks. “Can they help determine how you would treat it?”

Consider a blow to the head during snowboarding. “How do you decide on return to play?" Paris asks. "How do you treat them? The same questions are true for boxing, IED blasts in the military and head-to-head impact in soccer or football."

 “Our goal is to continue development and make the instrumented mouthpiece small enough to be useful and practical in all these situations." Birmingham and two other undergraduate research assistants,  Lilan Smith and Kaelin Ellis, have joined Paris in data gathering.

Deriving angular accelerations: 'There's a bit of math there.'

What they measure

Paris and the INNOVATE team use accelerometers on the mouthpiece to measure linear accelerations. From those, they are able to mathematically determine angular accelerations. (That’s the poetic blue scrawl on the conference room whiteboard. Yes, “There’s a little bit of math there,” Paris quips.) 

What’s the difference between the two types of accelerations? For linear, think of the head moving forward and backward, side to side or up and down. For angular accelerations, think of the top of the head tipping backward, the chin coming up. In aviation, this is known as roll, pitch and yaw.

                                      Research includes video analysis of ball-to-head impact.

A visual Paris employs to explain the difference is a glass half-full of iced tea. Push it side to side and ice and liquid moves with the glass. That’s linear movement. 

Spin the glass, and the ice and liquid stay immobile while the glass moves around it. That’s angular movement. 

The accelerometers he’s using, by the way, are similar to what you’ll find in your iPhone, car airbags or Wii handheld devices. Even runners use them in their shoes. Part of what’s making the development of an instrumented mouthpiece possible is the decreasing size and cost of accelerometers.

Sports where helmets are common have an advantage, Paris says. The data logger and transmitter can be installed in the helmet; even football helmets with mouth guards attached offer an advantage because wiring to the transmitter could pass through the attachment mechanism. 

Boxing, like many sports performed without a helmet, offers more challenge.

But since lots of contact sports require mouthguards anyway, why not use them more fully to measure impact to the skull? Paris aims to refine the mouthguard into a smaller and smaller device.

“John Lund said it best,” Paris recalls. “ ‘In 20 years, nobody will be putting a dumb piece of plastic in their mouth.’ ” 

Why would you, when you could use a “smart” mouthguard that delivers nuanced information about the impact status of your brain?

Paris is enthusiastic about the capabilities of the new mouthguard and the acceleration data his team is collecting. He’s exploring patent opportunities now. 

Honored with an Exemplar Award for student mentoring 

This spring, Paris was singled out for a special honor given to faculty who do an exceptional job mentoring students outside the traditional classroom setting. The presentation took place during the Undergraduate Research Symposium this spring; Brock accepted the award for Paris, who was obligated to attend committee meetings for engineering curriculum updates at the time. 

It was at least fitting that she received it for him; she had nominated him after witnessing his work with undergraduates. In her letter, she wrote, "He encourages his students to set high goals, and it is worth noting that two of his research mentees have been accepted at top graduate programs, one at Columbia University in New York and another at the University of Oxford in England."

One of the groups he mentored developed a spinal rod bender, used during back surgery, for which a patent application has been filed. 

“He’s a one-man undergraduate research program!” Brock said when she happened by the conference room where we were talking. She even arranged to frame the award so it could hang on his wall instead of compete for space on a jam-packed desk.

Julia DelSignore, left.

Andrew Cochrane, right,Tessa Kara, center.

Two students also nominated him for the Exemplar. One was Andrew Cochrane, who double majored in mechanical and electrical engineering and received the $2,000 Discovery Award for his academic achievements. 

The other was Julia DelSignore, who collaborated on early soccer impact testing and received a Discovery grant to help with travel expenses to present research at the 12th Pan American Congress of Applied Mechanics in Port of Spain, Trinidad. DelSignore is pictured at left with professors Paris and Brock during the Trinidad conference. You can download a PDF of their paper here.

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Anthony Paris

Anthony Paris joined UAA's faculty as an assistant professor of engineering in 2007. He was a research assistant professor at Boise State University in Idaho before that. He earned his B.S.  and M.S. in mechanical engineering at Washington University in St. Louis, and his doctorate in theoretical and applied mechanics from University of Illinois at Urbana-Champaign.

When he’s not in the lab gathering data or working calculations on the whiteboard, Paris can be found practicing yoga at a local Anchorage studio.