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2.3 MECHANICAL ENGINEERING, Medical engineering

Publication Details

Institute of Mechanical Engineers Part H Engineering in Medicine

Proc IMechE Part H: J Engineering in Medicine 1–10 IMechE 2019.

DOI: 10.1177/0954411919850961


Background: The requirement to measure the number and severity of head impacts in sports has led to the development of wearable sensors.

Aim: The objective of this study was to determine the reliability and accuracy of a wearable head impact sensor: xPatch, X2Biosystems Inc.

Methods: The skin mounted sensor, xPatch, was fixed onto a Hybrid III headform, and dropped using an impact test rig. Four hundred impacts were performed, ranging from 20 to 200g linear acceleration, and impact velocities of 1.2m/s to 3.9m/s. During each impact, the peak linear acceleration, angular velocity and angular acceleration, were recorded and compared to reference calibrated data. Impacts were also recorded using a high-speed video camera.

Results: The linear acceleration recorded by the xPatch during frontal and side impacts had errors of up to 24% when compared to the referenced data. The angular velocity and angular acceleration had substantially larger errors of up to 47.5% and 57% respectively. The location of the impact had a significant effect on the results: if the impact was to the side of the head, the device on that side may have an error of up to 71%, thus highlighting the importance of device location. All impacts were recorded using two separate xPatches and, in certain cases, the difference in angular velocity between the devices was 43%.

Conclusion: The xPatch can be useful for identifying impacts and recording linear accelerations during front and side impacts, but the rotational velocity and acceleration data needs to be interpreted with caution.


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