Integrating mouthguard kinematics, finite element brain strain, and plasma biomarkers to explore brain injury thresholds in collision sport

James W. Hickey, Emily Yik Kwan Chan, Lauren J Evans, William T. O’Brien, Becca Xie, Spencer Roberts, Sarah E. Butler, Joel Ernst, William Ji Quan Zhou, Karl Zimmerman, Gershon Spitz, Thomas D Parker, Terence J O'Brien, Sandy R. Shultz, David Sharp, Mazdak Ghajari, Stuart J. McDonald

medRxiv, 2026

Abstract

Purpose Identifying head impacts linked to brain injury in sport remains challenging. Instrumented mouthguards quantify head-impact kinematics, and finite element (FE) modelling can transform these data into brain strain estimates, which may better reflect injury risk than kinematics alone. Here, we examined associations between mouthguard-measured kinematics, FE-derived strain, and plasma brain injury biomarker GFAP following head impacts. Methods We analysed 41 video-verified impacts from male Australian football players, including 22 assessed for concussion (17 diagnosed) and 19 unassessed. Instrumented mouthguards recorded peak linear acceleration (PLA), peak rotational acceleration, and peak rotational velocity (PRV). Brain strain was estimated using the Imperial College FE brain model, and plasma GFAP was quantified using Simoa. Biomechanical-GFAP associations were examined using Spearman correlations and segmented regression. Results For impacts overall, plasma GFAP was moderately correlated with PLA (ρ=0.46, 95% CI: 0.20–0.66), PRV (ρ=0.53, 95% CI: 0.20–0.78), and strain (ρ=0.60, 95% CI: 0.32–0.80). Associations were stronger within concussion cases for strain (ρ=0.86, 95%…

Cite as (BibTeX)

@article{hickey-2026-integrating-mouthguard-kinematics-finite,
  title={Integrating mouthguard kinematics, finite element brain strain, and plasma biomarkers to explore brain injury thresholds in collision sport},
  author={James W. Hickey and Emily Yik Kwan Chan and Lauren J Evans and William T. O’Brien and Becca Xie and Spencer Roberts and Sarah E. Butler and Joel Ernst and William Ji Quan Zhou and Karl Zimmerman and Gershon Spitz and Thomas D Parker and Terence J O'Brien and Sandy R. Shultz and David Sharp and Mazdak Ghajari and Stuart J. McDonald},
  journal={medRxiv},
  year={2026},
  doi={10.64898/2026.08.26.26360869}
}