Laboratory Validation of Two Wearable Sensor Systems for Measuring Head Impact Severity in Football Players
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Wearable sensors can measure head impact frequency and magnitude in football players. Our goal was to quantify the impact detection rate and validity of the direction and peak kinematics of two wearable sensors: a helmet system (HITS) and a mouthguard system (X2). Using a linear impactor, modified Hybrid-III headform and one helmet model, we conducted 16 impacts for each system at 12 helmet sites and 5 speeds (3.6–11.2 m/s) (N = 896 tests). Peak linear and angular accelerations (PLA, PAA), head injury criteria (HIC) and impact directions from each device were compared to reference sensors in the headform. Both sensors detected ~96% of impacts. Median angular errors for impact directions were 34° for HITS and 16° for X2. PLA, PAA and HIC were simultaneously valid at 2 sites for HITS (side, oblique) and one site for X2 (side). At least one kinematic parameter was valid at 2 and 7 other sites for HITS and X2 respectively. Median relative errors for PLA were 7% for HITS and -7% for X2. Although sensor validity may differ for other helmets and headforms, our analyses show that data generated by these two sensors need careful interpretation.
KeywordsHead impact Wearable sensors Validity Acceleration Concussion Football
This study was funded by the National Football League (NFL). The authors thank Chris Withnall, Michael Wonnacott, Dave Halstead and Elizabeth McCalley for helping refine the protocol and acquire the data; and Christoph Mack, Jason Thibado, Jonathan Beckwith, Richard Greenwald, and Thad Ide for answering questions about their products. Our conclusions do not reflect the views of the NFL. SWM is partly funded by the Centers for Disease Control and Prevention (R49-CE002479). The NFL paid MEA Forensic for time and disbursements related to work performed by GPS, ALD, SJB and other MEA employees for this study. GPS and his spouse own shares in MEA Forensic, and GPS, ALD and SJB are salaried employees of MEA Forensic. KMG is a member of the NFL’s Head, Neck and Spine Committee and Chair of the Subcommittee on Equipment and Playing Rules. SWM is associated with the Datalys Center for Sports Injury Research and Prevention. None of the authors have a financial interest in either device. Biokinetics & Associates produce the MLSH and linear impactor, but had no hand in post-processing the data reported here. The NFL also paid Biokinetics & Associates and Southern Impact Research Center for their staff time, disbursements and lab usage. Drs. Barry Myers and David Meaney worked as paid consultants to the NFL and contributed to developing the protocol.
- 6.Cobb, B. R., A. MacAlister, T.J. Young, A. R. Kemper, S. Rowson, and S. M. Duma. Quantitative comparison of Hybrid III and National Operating Committee on Standards for Athletic Equipment headform shape characteristics and implications on football helmet fit. In: Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology. 229, 2015, pp. 39–46.Google Scholar
- 12.Gennarelli, T.A., L.E. Thibault, G. Tomei, R. Wiser, D. Graham and J. Adams. Directional dependence of axonal brain injury due to centroidal and non-centroidal acceleration (872197). Proceedings of 31st Stapp Car Crash Conference, 1987, pp. 49–53.Google Scholar
- 14.Guskiewicz, K. M., J. P. Mihalik, V. Shankar, S. W. Marshall, D. H. Crowell, S. M. Oliaro, M. F. Ciocca, and D. N. Hooker. Measurement of head impacts in collegiate football players—relationship between head impact biomechanics and acute clinical outcome after concussion. Neurosurgery 61:1244–1253, 2007.CrossRefPubMedGoogle Scholar
- 19.Ji, S., H. Ghadyani, R. P. Bolander, J. G. Beckwith, J. C. Ford, T. W. McAllister, L. A. Flashman, K. D. Paulsen, K. Ernstrom, S. Jain, R. Raman, L. Zhang, and R. M. Greenwald. Parametric comparisons of intracranial mechanical responses from three validated finite element models of the human head. Ann. Biomed. Eng. 42:11–24, 2013.CrossRefGoogle Scholar
- 20.Kent, J. T. The Fisher-Bingham distribution on the sphere. J. R. Statist. Soc. B 44:71–80, 1982.Google Scholar
- 21.Knox, T, J. Pellettiere, C. Perry, J. Plaga, and J. Bonfeld. New sensors to track head acceleration during possible injurious events (2008-01-2976). SAE International Journal of Passenger Cars—Electronic and Electrical Systems 1, 2008, pp. 652–663.Google Scholar
- 25.McAllister, T. W., J. C. Ford, S. Ji, J. G. Beckwith, L. A. Flashman, K. Paulsen, and R. M. Greenwald. Maximum principal strain and strain rate associated with concussion diagnosis correlates with changes in corpus callosum white matter indices. Ann. Biomed. Eng. 40:127–140, 2011.CrossRefPubMedPubMedCentralGoogle Scholar
- 26.McCulloch, C. E., S. R. Searle, and J. M. Neuhaus. Generalized, Linear, and Mixed Models (2nd ed.). Hoboken: Wiley, p. 424, 2008.Google Scholar
- 36.Rowson, S., S. M. Duma, J. G. Beckwith, J. J. Chu, R. M. Greenwald, J. J. Crisco, P. G. Brolinson, A.-C. Duhaime, T. W. McAlister, and A. C. Maerlender. Rotational head kinematics in football impacts: an injury risk function for concussion. Ann. Biomed. Eng. 40:1–13, 2012.CrossRefPubMedGoogle Scholar
- 39.Stroup, W. W. Generalized Linear Mixed Models: Modern Concepts, Methods and Applications. Boca Raton: CRC Press, p. 555, 2012.Google Scholar
- 44.Wonnacott, M., and C. Withnall. Development of an articulating mandible headform having force sensing temporomandibular joints (2010-01-0136). Society of Automotive Engineers, 2010.Google Scholar