A Pilot Study Quantifying Center of Mass Trajectory during Dynamic Balance Tasks Using an HTC Vive Tracker Fixed to the Pelvis.

Susanne M Van Der Veen,James S Thomas

doi:10.3390/s21238034

Susanne M Van Der Veen, James S Thomas

Open Access

https://doi.org/10.3390/s21238034

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Abstract

Fall rates are increasing among the aging population and even higher falls rates have been reported in populations with neurological impairments. The Berg Balance Scale is often used to assess balance in older adults and has been validated for use in people with stroke, traumatic brain injury, and Parkinson’s disease. While the Berg Balance Scale (BBS) has been found to be predictive of the length of rehabilitation stay following stroke, a recent review concluded the BBS lacked predictive validity for fall risk. Conversely, sophisticated measures assessing center of mass (COM) displacement have shown to be predictive of falls risk. However, calculating COM displacement is difficult to measure outside a laboratory. Accordingly, we sought to validate COM displacement measurements derived from an HTC Vive tracker secured to the pelvis by comparing it to COM derived from ‘gold’ standard laboratory-based full-body motion capture. Results showed that RMS between the COM calculated from HTC Vive tracker and full body motion capture agree with an average error rate of 2.1 ± 2.6 cm. Therefore, we conclude measurement of COM displacement using an HTC Vive tracker placed on the pelvis is reasonably representative of laboratory-based measurement of COM displacement.

Highlights

Falls are a great cost to the society
Most falls happen in elderly populations, and even more in populations with balance deffecits associated with stroke [2,3], traumatic brain injury (TBI), or Parkinson’s disease (PD) [4]
An average RMS of 2 cm represents close tracking of the center of mass (COM) by the HTC Vive tracker, as you can see in Table 2 and Figure 3, the COM measurements derived by the two systems shows greater deviations in the more dynamic tasks such as picking up an object, looking over the shoulder, and turning 360◦

Summary

Introduction

Falls are a great cost to the society. Approximately $50 billion is spent on non-fatal falls and another $754 million on 28,486 fatal falls yearly [1]. The Berg Balance Scale (BBS) is often used to assess balance in clinic and consists of 14 tasks (Table 1) that a patient completes, and therapist scores on a 0–4-point scale. The BBS is a well-established and validated [7,8,9] clinical tool for measuring balance deficits and has been validated for balance assessment in a wide range of populations—including stroke, Parkinson’s disease, and TBI [7,8,9,10,11,12,13,14]. The BBS has been found to be predictive of length of stay, discharge destination, motor ability and disability level post-stroke and low fall risk [15]. The BSS does not have strong predictive value of high falls risk [8,11]

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