Washabaugh Edward P, Kalyanaraman Tarun, Adamczyk Peter G, Claflin Edward S, Krishnan Chandramouli
Department of Physical Medicine and Rehabilitation, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA.
Department of Physical Medicine and Rehabilitation, Michigan Medicine, University of Michigan, Ann Arbor, MI, USA.
Gait Posture. 2017 Jun;55:87-93. doi: 10.1016/j.gaitpost.2017.04.013. Epub 2017 Apr 12.
Inertial measurement units (IMUs) are small wearable sensors that have tremendous potential to be applied to clinical gait analysis. They allow objective evaluation of gait and movement disorders outside the clinic and research laboratory, and permit evaluation on large numbers of steps. However, repeatability and validity data of these systems are sparse for gait metrics. The purpose of this study was to determine the validity and between-day repeatability of spatiotemporal metrics (gait speed, stance percent, swing percent, gait cycle time, stride length, cadence, and step duration) as measured with the APDM Opal IMUs and Mobility Lab system. We collected data on 39 healthy subjects. Subjects were tested over two days while walking on a standard treadmill, split-belt treadmill, or overground, with IMUs placed in two locations: both feet and both ankles. The spatiotemporal measurements taken with the IMU system were validated against data from an instrumented treadmill, or using standard clinical procedures. Repeatability and minimally detectable change (MDC) of the system was calculated between days. IMUs displayed high to moderate validity when measuring most of the gait metrics tested. Additionally, these measurements appear to be repeatable when used on the treadmill and overground. The foot configuration of the IMUs appeared to better measure gait parameters; however, both the foot and ankle configurations demonstrated good repeatability. In conclusion, the IMU system in this study appears to be both accurate and repeatable for measuring spatiotemporal gait parameters in healthy young adults.
惯性测量单元（IMU）是一种小型可穿戴传感器，在临床步态分析中具有巨大的应用潜力。它们能够在诊所和研究实验室之外对步态和运动障碍进行客观评估，并且可以对大量步数进行评估。然而，这些系统在步态指标方面的重复性和有效性数据较为稀少。本研究的目的是确定使用APDM Opal IMU和移动实验室系统测量的时空指标（步态速度、站立百分比、摆动百分比、步态周期时间、步长、步频和步幅持续时间）的有效性和日间重复性。我们收集了39名健康受试者的数据。受试者在两天内分别在标准跑步机、分体式跑步机或地面上行走时接受测试，IMU放置在两个位置：双脚和双踝。将IMU系统进行的时空测量与仪器化跑步机的数据或使用标准临床程序进行验证。计算系统在不同日期之间的重复性和最小可检测变化（MDC）。在测量所测试的大多数步态指标时，IMU显示出高至中等的有效性。此外，当在跑步机和地面上使用时，这些测量结果似乎是可重复的。IMU的足部配置似乎能更好地测量步态参数；然而，足部和踝部配置均显示出良好的重复性。总之，本研究中的IMU系统在测量健康年轻成年人的时空步态参数方面似乎既准确又可重复。
