The next time you play Angry Birds, consider this — the same type of sensors that capture movements on your phone are also playing a role in biomedical research to make sports safer for children.
For the past three years, investigators at the Stanford University School of Medicine and Lucile Packard Children’s Hospital Stanford have been using these sensors in new ways to understand and measure what happens when athletes experience collisions that lead to brain injury.
Though abundant media attention has been giving to concussions in adult players in the National Football League, children—both boys and girls—are also being wide affected by milder, repetitive injuries. In the terms of numbers, there are millions of children nationwide playing recreational sports, compared with only a couple thousand players in the NFL. Many young athletes are now playing harder and faster with frequent incidental contact in a variety of sports, such as basketball, soccer, and lacrosse.
“The problem of concussions is more pervasive than we previously thought,” says Paul Fisher, MD, chief of child neurology. “We’re now defining concussions more broadly as a blow to the head with some neurological effect such as headache, dizziness, or nausea — not just loss of consciousness.”
Ava James, 13, recently came to Fisher’s clinic after suffering nausea, dizziness, and headaches following a hit to her head during soccer practice. She is part of a growing trend — approximately half a million children nationwide visit the emergency room each year for sports-related concussions. Many others are not seen in the emergency room and under-report their symptoms. The concussion rate for girls has risen 21 percent annually over 11 years, a greater increase than the concussion rate for boys at 14 percent annually.
The Science of Impacts
Though concussions are a growing concern, very little is actually known about how different types of impact actually cause injuries to the brain. When players take a hard hit, the injuries and their effects are sometimes not felt or seen immediately afterwards. With different symptoms in different individuals, concussions are hard to diagnose, often undetectable on CT scans and largely dependent on players’ self-reports — if they’re honest.
In order to predict and prevent concussions, Stanford researcher David Camarillo, PhD, assistant professor of bioengineering, is developing an innovative approach that may be a game-changer in sports concussion research.
Using accelerometers and gyroscopes, the same types of sensors found in smartphones, Camarillo’s lab is gathering data about brain trauma as it occurs. Through a remarkable partnership with Stanford Athletics, most players on the Stanford football team wear mouthguards outfitted with sensors that record and measure the physics of every hit to the head during practices and games. In addition, by using ultra-high-definition, slowmotion cameras, Camarillo and his team are also closely observing and videotaping collisions — yielding footage that shows, down to each painful millisecond, how the impact of a hit ripples through players’ bodies.
“This story is still in the early stages,” Camarillo says, “but we’ve already seen some startling data.”
For reference, 1 G is the standard measure for the linear acceleration of gravity. In a car crash, the acceleration might reach 50 or 100 Gs. In some of the hardest hits in football, Camarillo and his team have observed linear acceleration of up to 150 Gs. This does not even account for angular acceleration, the rotation of a player’s head and neck after a hit. The Stanford study is one of the first to measure angular acceleration as an important factor that may also contribute to brain injuries.
In addition, incidents that may previously have been counted as just one hit are actually two successive collisions. A player experiences an initial impactduring a tackle, but the brain receives trauma again when the head collides with the ground — resulting in a double hit that generates more than one concussive impact.
By taking measurements on both non-injury events and injury events, Camarillo aims to narrow in and define the thresholds for injury. “Our ultimate goal,” he says, “is to discover the mechanism of concussion so that we can develop better preventive measures, particularly for young athletes who would be at risk of brain damage and impaired cognitive development.”
Though the research may take five or 10 more years, the data collected from Stanford football players may also help to determine the “doses” of impact that children and adolescents are experiencing in recreational activity. With a grant from the David and Lucile Packard Foundation, the project is now expanding to include testing other types of wearable head sensors that could be more widely used in women’s sports, where mouthguards are not required equipment. This basic research and pilot studies in Stanford women’s lacrosse and soccer players may help researchers better understand the different effects of head injuries in girls’ sports.
Gerald Grant, MD, FACS, associate professor of neurosurgery, is a new arrival at Lucile Packard Children’s Hospital Stanford, but has quickly embraced the opportunity to advance sports concussion research here. A veteran of the U.S. Air Force and a pediatric neurosurgeon, Grant has treated patients ranging from soldiers with blast concussive injuries in Iraq, to an increasing number of girls with soccer concussions in clinic.
Grant notes that more and more research is showing that head injuries may have a cumulative effect. “It’s not just a severe blow,” he says, “but a series of repetitive, milder blows that can actually result in significant damage over time.”
“Considering that the average college soccer player heads the ball hundreds or thousands of times a season, we have to better understand and speak up about these issues,” Grant adds. Since his arrival at Stanford last fall, Grant has joined with Camarillo, Fisher, and others to move the research forward, leveraging the university’s tremendous wealth of expertise.
“We have incredible athletes and scholars at Stanford — we’re like the Greek city-state of Sparta,” notes Fisher with a smile. Joking aside, there is indeed a unique confluence of elite athleticism and deep intellectual curiosity here, even in the players and coaches who willingly and actively participate in the research. In addition, the opportunity to collaborate across disciplines such as engineering, biodesign, and medicine at Stanford University makes advances more readily achievable.
For worried parents, pediatricians Fisher and Grant are quick to point out that the positive effects of children participating in sports — such as improved physical health, body image, and self-esteem — far outweigh the risks of head injury. After two weeks of rest, 13-year-old soccer player Ava was ready to return to normal activity, though it took five months for her headaches to subside. While the researchers continue to work toward more definitive metrics to predict and prevent head injuries, they encourage coaches, players, and parents all to become more educated about concussions, including the importance of following rules and using proper safety equipment, giving young athletes adequate time to heal both physically and mentally, and returning to the classroom before returning to the playing field.
This article appeared in the Lucile Packard Children’s News publication in Spring 2014.
