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AAOS Now

Published 10/1/2013
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Amber Blake

Getting HIT to Reduce Concussion Injury

Research aims to measure the impact on the head

The 2013–2014 NFL season is in full swing, and all across the country, college and high school stands are also filled with cheering fans.

Although football has been a favorite fall pastime for years, growing concerns over the number of concussion injuries sustained by players have overshadowed what was once a fun, family sport. Recently, the NFL reached a settlement agreement for $765 million over concussion-related brain injuries, and a similar lawsuit against the National Collegiate Athletic Association (NCAA) is in mediation.

The Centers for Disease Control and Prevention (CDC) defines a concussion as “a type of traumatic brain injury that can be caused by a bump, blow, or jolt to the head. Concussions can also occur from a blow to the body that causes the head and brain to move rapidly back and forth—literally causing the brain to bounce around and twist within the skull.”

This type of injury can have a traumatic effect on the brain. According to the CDC, “this sudden movement of the brain causes stretching, damaging the cells and creating chemical changes in the brain. Once these changes occur, the brain is more vulnerable to further injury and sensitive to any increased stress until it fully recovers.”

Based on that definition, football players sustain concussions on a regular basis. In fact, most players probably incur several concussions without even realizing it.

Measuring with the HIT system
“One of the few things we know about concussions is that you are more likely to have a repeat concussion after you have had one concussion,” explained Joseph “Trey” Crisco, PhD, professor of orthopaedics and director of the bioengineering laboratory at Brown University.

Dr. Crisco, a member of the Orthopaedic Research Society, and his team are seeking not only to understand concussions, but to prevent them more effectively. However, many questions about these types of injuries remain.

“We don’t know if athletes sustain repeated concussions because something changes in the brain or if it’s their style of play,” Dr. Crisco explained. “We don’t know if athletes are more susceptible to one big head impact or lots of medium impacts. We don’t know if female athletes are more or less sensitive to head impacts than male athletes.”

Answering these questions is difficult because many athletes and coaches don’t always recognize when a concussion has occurred. That’s where the Head Impact Telemetry (HIT) system comes into play. It was developed by Dr. Crisco’s team and Richard M. Greenwald, PhD, president and cofounder of Simbex, a research and product development company specializing in biomechanical feedback systems.

The HIT system is able to measure how hard, how often, and where on a helmet an impact occurs. It consists of six accelerometers that are located within a special liner inside the helmet. This special liner elastically couples the accelerometers to the head, isolating the head from shell vibrations. With every hit, the acceleration of the head is recorded and automatically transmitted to a computer on the sideline. If desired, a beeper can notify the medical professional of especially hard hits that they might not have seen.

Armed with these tools, scientists are able to measure head impact exposure for the first time. Drs. Greenwald, Crisco, and Stefan Duma, PhD, who heads the Virginia Tech/Wake Forest University School of Biomedical Engineering and Sciences, have received funding from the National Institutes of Health and the National Institute of Child Health and Human Development to conduct research on concussions. Already, their research has shed new light on head impact exposures, concussion mechanism, and the role gender plays in concussion injury.

“It is our hope,” said Dr. Crisco, “that our research will ultimately lead to positive changes in football rules and practice at the collegiate and youth level, improved helmet designs and testing, and a reduction in concussion injuries.”

Preventing concussions remains a top priority because no treatments for those who sustain these injuries currently exist. With continued research, perhaps all athletes—youth and professional—will be able to play football and other contact sports without worrying about the effects a bump on the head will have on the rest of their lives.

Amber Blake is the communications manager for the Orthopaedic Research Society (ORS). She can be reached at blake@ors.org

Bottom Line

  • Concussions can occur when a blow to the body causes the brain to bounce around and twist within the skull.
  • This sudden movement can damage brain cells and create chemical changes in the brain, making the brain more vulnerable to further injury.
  • The Head Impact Telemetry (HIT) system is designed to measure how hard, how often, and where on a helmet an impact occurs, as well as recording the acceleration of the head, to enable researchers to determine head impact exposure.