Measuring Head Impact Exposure and Mild Traumatic Brain Injury in Humans

Helmeted sports such as football offer a unique opportunity to study head injury biomechanics in live human subjects. Impact reconstruction using game videos and real-time measurements of head kinematics in football provide a method of quantifying the head impact exposure athletes experience. A total of 58 impacts from NFL games have been reconstructed using Hybrid III crash test dummies, including 25 concussive impacts. Roughly 2 million impacts have been recorded using helmet-mounted accelerometer devices, with 105 concussive impacts. Similar values have been found for peak linear acceleration, one of the best predictors of concussion, using the two methods. From the NFL impact reconstructions, researchers found a peak linear acceleration value of 98 ± 28 g which is not substantially different from the value of 105 ± 27 g from the helmet-mounted sensor data. Both methods provide valuable head impact biomechanics data which are used to quantify impact exposure in football and assess injury risk due to head impact. Helmet mounted accelerometers have the added benefit of collecting every impact a player sustains while wearing the sensors, giving more detailed impact frequency data and many more data points. Future research will focus on expanding the head impact data set, especially at the youth level. The expanded data set will lead to improved injury risk curves which will guide future safety standards in sports as well as other areas, including the automotive industry and military, where head injury is a concern.