Safieddine Doha, Chkeir Aly, Herlem Cyrille, Bera Delphine, Collart Michèle, Novella Jean-Luc, Dramé Moustapha, Hewson David J, Duchêne Jacques
University of Technology of Troyes (UTT), Troyes, France.
Les Arcades Prevention Centre, Troyes, France.
Med Eng Phys. 2017 Nov;49:14-21. doi: 10.1016/j.medengphy.2017.07.005. Epub 2017 Sep 19.
Falls are a major cause of death in older people. One method used to predict falls is analysis of Centre of Pressure (CoP) displacement, which provides a measure of balance quality. The Balance Quality Tester (BQT) is a device based on a commercial bathroom scale that calculates instantaneous values of vertical ground reaction force (Fz) as well as the CoP in both anteroposterior (AP) and mediolateral (ML) directions. The entire testing process needs to take no longer than 12 s to ensure subject compliance, making it vital that calculations related to balance are only calculated for the period when the subject is static. In the present study, a method is presented to detect the stabilization period after a subject has stepped onto the BQT. Four different phases of the test are identified (stepping-on, stabilization, balancing, stepping-off), ensuring that subjects are static when parameters from the balancing phase are calculated. The method, based on a simplified cumulative sum (CUSUM) algorithm, could detect the change between unstable and stable stance. The time taken to stabilize significantly affected the static balance variables of surface area and trajectory velocity, and was also related to Timed-up-and-Go performance. Such a finding suggests that the time to stabilize could be a worthwhile parameter to explore as a potential indicator of balance problems and fall risk in older people.
跌倒是老年人死亡的主要原因之一。用于预测跌倒的一种方法是分析压力中心（CoP）位移，它可衡量平衡质量。平衡质量测试仪（BQT）是一种基于商用浴室秤的设备，可计算垂直地面反作用力（Fz）的瞬时值以及前后（AP）和左右（ML）方向上的压力中心。整个测试过程需要不超过12秒，以确保受试者配合，这使得与平衡相关的计算仅在受试者静止期间进行至关重要。在本研究中，提出了一种方法来检测受试者踏上BQT后的稳定期。确定了测试的四个不同阶段（踏上、稳定、平衡、离开），以确保在计算平衡阶段的参数时受试者是静止的。该方法基于简化的累积和（CUSUM）算法，能够检测不稳定和稳定姿势之间的变化。稳定所需的时间显著影响了表面积和轨迹速度等静态平衡变量，并且还与计时起立行走测试表现相关。这样的发现表明，稳定时间可能是一个值得探索的参数，可作为老年人平衡问题和跌倒风险的潜在指标。
