Center for Injury Research and Prevention

Head Impact Sensors Research

This research focused on evaluating the accuracy of head impact sensor systems designed to be implemented for helmeted and non-helmeted sports to measure the kinematics of head impact of athletes in real sports settings.  Such head impact sensors are key to research efforts to identify thresholds for injury-causing impacts across the pediatric age range and across a range of real world impact conditions.

Rigidly mounted Hybrid III 50th percentile male ATD head and neck with pneumatic linear impactor

Evaluating Helmet-Based Kinematic Measurement Systems Used to Study Mild Traumatic Brain Injury in Real-World Scenarios

This line of research used sensor-instrumented helmets to study mild traumatic brain injury or concussion thresholds and mechanisms in ice hockey by observing actual athletes engaged in games and practices. While head impact sensors cannot diagnose mild traumatic brain injury, they measure, calculate and report the severity of the impact to the head and can serve as a second set of eyes for medical professionals by identifying players that need clinical evaluation. This research seeks to validate these sensors’ accuracy and reliability by testing helmets fitted with two different types of sensors. For each sensor, an anthropomorphic test device (ATD), or crash test dummy head and neck, was fitted with a hockey helmet equipped with the sensors and subjected to repeated impacts of multiple intensities and directions.

Published Studies

  • The head acceleration measured by the six-accelerometer Head Impact Telemetry (HIT) System was compared with reference acceleration measured at the center of gravity of the ATD head. Linear acceleration is directly measured in the HIT system and rotational acceleration is estimated from the linear measures.  This is the first comprehensive evaluation of accuracy of peak head acceleration measured by the HIT System for hockey and highlighted important differences in accuracy with impact direction and interface between the head and helmet.  Accuracy was less than had previously been reported, specifically for rotational acceleration. Read the study abstract.
  • A different helmet-based system (the gForce Tracker, or GFT) measures the kinematics associated with head impacts by integrating the use of accelerometers as well as gyroscopes to directly measure rotational velocity. The GFT-reported linear and rotational kinematics were compared reference acceleration measured at the center of gravity of the ATD head to evaluate the system’s accuracy. Linear acceleration accuracy was similar to other sensor systems; however, rotational kinematics more closely matched the reference measures.  Differences in accuracy by impact direction, location of the sensor on the helmet, and helmet brand were noted. Read the study abstract.

Principal Investigators: Mari Allison, PhD, Kristy Arbogast, PhD

Funding: National Science Foundation, Center for Child Injury Prevention Studies, with additional support from Toyota North America Inc, National Highway Traffic Safety Administration, as well as SAFER- the Vehicle and Traffic Safety Centre at Chalmers University in Gothenburg, Sweden.

Read Sport Illustrated article about potential and limitations of current head impact sensors

Read more about Concussion research at CIRP.