Six Degree-of-Freedom Measurements of Human Mild Traumatic Brain Injury

Fidel Hernandez, Lyndia C. Wu, Michael C. Yip, Kaveh Laksari, Andrew R. Hoffman, Jaime R. Lopez, Gerald A. Grant, Svein Kleiven, David B. Camarillo

Research output: Contribution to journalArticlepeer-review

124 Scopus citations


This preliminary study investigated whether direct measurement of head rotation improves prediction of mild traumatic brain injury (mTBI). Although many studies have implicated rotation as a primary cause of mTBI, regulatory safety standards use 3 degree-of-freedom (3DOF) translation-only kinematic criteria to predict injury. Direct 6DOF measurements of human head rotation (3DOF) and translation (3DOF) have not been previously available to examine whether additional DOFs improve injury prediction. We measured head impacts in American football, boxing, and mixed martial arts using 6DOF instrumented mouthguards, and predicted clinician-diagnosed injury using 12 existing kinematic criteria and 6 existing brain finite element (FE) criteria. Among 513 measured impacts were the first two 6DOF measurements of clinically diagnosed mTBI. For this dataset, 6DOF criteria were the most predictive of injury, more than 3DOF translation-only and 3DOF rotation-only criteria. Peak principal strain in the corpus callosum, a 6DOF FE criteria, was the strongest predictor, followed by two criteria that included rotation measurements, peak rotational acceleration magnitude and Head Impact Power (HIP). These results suggest head rotation measurements may improve injury prediction. However, more 6DOF data is needed to confirm this evaluation of existing injury criteria, and to develop new criteria that considers directional sensitivity to injury.

Original languageEnglish (US)
Pages (from-to)1918-1934
Number of pages17
JournalAnnals of Biomedical Engineering
Issue number8
StatePublished - Aug 25 2015


  • Brain strain
  • Concussion
  • Finite element model
  • Instrumented mouthguard
  • Mild traumatic brain injury (mTBI)
  • Six degree-of-freedom (6DOF) kinematics

ASJC Scopus subject areas

  • Biomedical Engineering


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