Annals of Biomedical Engineering

, Volume 44, Issue 4, pp 1234–1245

In Vivo Evaluation of Wearable Head Impact Sensors

  • Lyndia C. Wu
  • Vaibhav Nangia
  • Kevin Bui
  • Bradley Hammoor
  • Mehmet Kurt
  • Fidel Hernandez
  • Calvin Kuo
  • David B. Camarillo
Article

DOI: 10.1007/s10439-015-1423-3

Cite this article as:
Wu, L.C., Nangia, V., Bui, K. et al. Ann Biomed Eng (2016) 44: 1234. doi:10.1007/s10439-015-1423-3

Abstract

Inertial sensors are commonly used to measure human head motion. Some sensors have been tested with dummy or cadaver experiments with mixed results, and methods to evaluate sensors in vivo are lacking. Here we present an in vivo method using high speed video to test teeth-mounted (mouthguard), soft tissue-mounted (skin patch), and headgear-mounted (skull cap) sensors during 6–13 g sagittal soccer head impacts. Sensor coupling to the skull was quantified by displacement from an ear-canal reference. Mouthguard displacements were within video measurement error (<1 mm), while the skin patch and skull cap displaced up to 4 and 13 mm from the ear-canal reference, respectively. We used the mouthguard, which had the least displacement from skull, as the reference to assess 6-degree-of-freedom skin patch and skull cap measurements. Linear and rotational acceleration magnitudes were over-predicted by both the skin patch (with 120% NRMS error for \(a_{\rm mag}\), 290% for \(\alpha _{\rm mag}\)) and the skull cap (320% NRMS error for \(a_{\rm mag}\), 500% for \(\alpha _{\rm mag}\)). Such over-predictions were largely due to out-of-plane motion. To model sensor error, we found that in-plane skin patch linear acceleration in the anterior–posterior direction could be modeled by an underdamped viscoelastic system. In summary, the mouthguard showed tighter skull coupling than the other sensor mounting approaches. Furthermore, the in vivo methods presented are valuable for investigating skull acceleration sensor technologies.

Keywords

Head impact sensors Traumatic brain injury Wearable sensors Instrumented mouthguard Instrumented skin patch Instrumented skull cap High speed video Soft tissue modeling 

Supplementary material

10439_2015_1423_MOESM1_ESM.pdf (44 kb)
Supplementary material 1 (pdf 44 KB)
10439_2015_1423_MOESM2_ESM.pdf (69 kb)
Supplementary material 2 (pdf 69 KB)
10439_2015_1423_MOESM3_ESM.pdf (76 kb)
Supplementary material 3 (pdf 75 KB)

Copyright information

© Biomedical Engineering Society 2015

Authors and Affiliations

  • Lyndia C. Wu
    • 1
  • Vaibhav Nangia
    • 2
  • Kevin Bui
    • 1
  • Bradley Hammoor
    • 1
  • Mehmet Kurt
    • 1
  • Fidel Hernandez
    • 2
  • Calvin Kuo
    • 2
  • David B. Camarillo
    • 1
    • 2
  1. 1.Department of BioengineeringStanford UniversityStanfordUSA
  2. 2.Department of Mechanical EngineeringStanford UniversityStanfordUSA