Measurement Efficiency of an Instrumented Mouthguard Under a Large Range of Head Accelerations and the Effects of Filtering

Abstract

Instrumented mouthguards (iMG) measure head kinematics in sport, but their measurements have not been validated at high levels of accelerations observed in those sports like rugby. In addition, the effects of filter cut-off frequency on the measured kinematics are still unknown. To address these questions, a drop testing helmeted head-form of an anthropometric testing device (ATD) was used to produce a range of accelerations and accurately control them. Peak linear acceleration (PLA), rotational velocity (PRV), rotational acceleration (PRA) and maximum principal strain (MPS) values were computed. The influence of filter cut-off frequency on peak kinematics was also calculated. Comparison of the peak values across ATD and iMG indicated high levels of agreement, with a total concordance correlation coefficient of 0.97 and intraclass correlation coefficients of 0.990 for PLA, 0.970 for PRV, 0.945 for PRA, and 0.970 for MPS. Cut-off frequencies of 100-300Hz did not significantly attenuate peak kinematics, but frequencies lower than 100Hz did. This is the first study to test an iMG under impact conditions seen in sport. The method presented can be used for in-lab validation of iMGs under head accelerations seen in sport. Furthermore, these results can contribute towards defining standards for filtering iMG data.