Head contacts in collegiate football measured with an instrumented mouthguard. Issue 5 (11th March 2013)

• Record Type: Journal Article
• Authors: Camarillo, David; Mattson, James; Flynn, Michael; Yang, Sheng; Shull, Pete; Shultz, Rebecca; Matheson, Gordon; Garza, Daniel
• Is Part Of: British journal of sports medicine. Volume 47:Issue 5(2013)
• Page Start: e1
• Page End: e1
• Publication Date: 2013-03-11
• Subjects: Sports medicine -- Periodicals; 617.1027
• DOI: 10.1136/bjsports-2012-092101.33
• Languages: English
• ISSNs: 0306-3674

Abstract

Abstract : Background: The clinical relationship between accumulated head impacts and chronic cognitive dysfunction is under increasing scrutiny. There is therefore a need to track an athlete's accumulation of head impacts. Objective: We sought to develop and test an inexpensive wireless device that could be widely used for monitoring blows to the head in football. Design: Prospective, descriptive. Setting: Stanford University scrimmages. Subjects: 16 males from 6 different positions. Methods: During four spring practice sessions, players wore mouthguards instrumented with three accelerometers and gyroscopes for measuring head motion. When the acceleration magnitude exceeded 15G (after 110 Hz low-pass filter), an event was recorded. Simultaneously, full-speed scrimmage sessions were video recorded from two perpendicular angles and later analysed for 'helmet-helmet contacts.' Plays were only considered if the subject's helmet was struck by the opposing player's helmet at the initial point of contact, or if the subject's helmet sustained "no-contact" at all during the play. Mouthguard events were then synchronised and evaluated during the time period of each play to determine agreement with video data. Results: Video analysis yielded 153 helmet-helmet contacts and 402 no-contacts. Mouthguard sensitivity for detecting observed helmet contact at the 15G threshold was 61% (95% CI 0.54 to 0.69) and the specificity was 91% (95% CI 0.88 to 0.93). Overall accuracy was 83%. Conclusion: Although the 15G threshold is based on published helmet telemetry clinical studies, 39% of observed helmet-helmet contacts were below this threshold. Further research is required to understand if lower acceleration contacts are clinically relevant, and if they can be accurately detected. Acknowledgements: We acknowledge the Stanford athletic training, videography, and football staff for their cooperation as well as X2 Impact Inc. for donation of mouthguards.