Hsieh Katherine L, Roach Kathleen L, Wajda Douglas A, Sosnoff Jacob J
Department of Kinesiology and Community Health, University of Illinois at Urbana Champaign, Urbana, IL, USA.
Department of Health and Human Performance, Cleveland State University, Cleveland, OH, USA.
Gait Posture. 2019 Jan;67:160-165. doi: 10.1016/j.gaitpost.2018.10.005. Epub 2018 Oct 9.
Falls are the leading cause of injury related death in older adults. Impaired postural stability is a predictor of falls but is seldom objectively assessed in clinical or home settings. Embedded accelerometers within smartphones offer potential to objectively measure postural stability. The purpose of this study was to determine if a smartphone embedded accelerometer can measure static postural stability and distinguish older adults at high levels of fall risk.
Thirty older adults (age: 65.9 ± 8.8) underwent seven balance tests while standing on a force plate and holding a smartphone against their chest in a standardized order. Participants also completed the Physiological Profile Assessment to assess their fall risk. Center of pressure (COP) parameters from the force plate including velocity in the anterioposterior (AP) and mediolateral (ML) directions and 95% confidence ellipse were derived. Maximum acceleration and root mean square (RMS) in ML, AP and vertical axes were derived from the smartphone. Spearman rank-order correlations between force plate and smartphone measures were conducted, and receiver operating characteristic (ROC) and the area under the curves (AUC) were constructed to distinguish between low and high fall risk.
There were moderate to strong significant correlations between measures derived from the force plate and measures derived from the smartphone during challenging balance conditions (ρ = 0.42-0.81; p < 0.01-0.05). The AUC for ROC plots were significant for all COP measures during challenging balance conditions (p < 0.01-0.05). The AUC for ROC plots were significant for RMS vertical and AP during challenging balance conditions (p = 0.01-0.04).
This study provides evidence that a smartphone is a valid measure of postural stability and capable of distinguishing fall risk stratification in older adults. There is potential for smartphones to offer objective, fall risk assessments for older adults.
跌倒为老年人因伤致死的首要原因。姿势稳定性受损是跌倒的一个预测指标，但在临床或家庭环境中很少对其进行客观评估。智能手机内置的加速度计提供了客观测量姿势稳定性的潜力。本研究的目的是确定智能手机内置加速度计能否测量静态姿势稳定性并区分跌倒风险较高的老年人。
30名老年人（年龄：65.9±8.8）按标准化顺序站在测力板上并将智能手机贴在胸前时接受了七项平衡测试。参与者还完成了生理特征评估以评估其跌倒风险。从测力板得出压力中心（COP）参数，包括前后（AP）和内外侧（ML）方向的速度以及95%置信椭圆。从智能手机得出ML、AP和垂直轴的最大加速度和均方根（RMS）。对测力板和智能手机测量值之间进行Spearman等级相关性分析，并构建受试者工作特征（ROC）曲线及曲线下面积（AUC）以区分低跌倒风险和高跌倒风险。
在具有挑战性的平衡条件下，测力板得出的测量值与智能手机得出的测量值之间存在中度到高度显著相关性（ρ = 0.42 - 0.81；p < 0.01 - 0.05）。在具有挑战性的平衡条件下，所有COP测量值的ROC曲线AUC均显著（p < 0.01 - 0.05）。在具有挑战性的平衡条件下，RMS垂直和AP的ROC曲线AUC显著（p = 0.01 - 0.04）。
本研究提供了证据表明智能手机是姿势稳定性的有效测量工具，并且能够区分老年人的跌倒风险分层。智能手机有潜力为老年人提供客观的跌倒风险评估。
