Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Disabil Rehabil. 2013 May;35(9):725-31. doi: 10.3109/09638288.2012.707745.
The current study compared output from the vertical axis of two models of ActiGraph accelerometers under free-living and laboratory conditions in persons with multiple sclerosis (MS) and matched controls.
The sample included 41 cases of MS and 41 controls matched by age, sex, height and weight. Participants concurrently wore 7164 and GT3X accelerometers for 6 days under free-living conditions, and undertook up to five, 6-minute periods of walking at five speeds on a motor-driven treadmill.
Under free-living conditions, there was substantial, but not absolute, agreement (Intraclass correlation = 0.983) between devices and the output from the model 7164 accelerometer was significantly greater (p < 0.01) than that of the GT3X, resulting in a 7.0% difference between devices. The treadmill-walking conditions indicated that this difference in output between accelerometers was based on slow-walking speeds where there was a statistically significant (p < 0.01) and 30.3% discrepancy.
The ActiGraph model 7164 and GT3X accelerometers are not interchangeable under free-living conditions, and the discrepancy in measurement between devices might be explained by the difference in output under slow-walking conditions. Researchers and clinicians should be aware of the difference in output between generations of ActiGraph accelerometers, and perhaps other brands, in future applications involving persons with MS and controls.
本研究比较了两种 ActiGraph 加速度计在多发性硬化症（MS）患者和匹配对照者的自由生活和实验室条件下的垂直轴输出。
该样本包括 41 例 MS 病例和 41 例按年龄、性别、身高和体重匹配的对照者。参与者在自由生活条件下同时佩戴 7164 和 GT3X 加速度计 6 天，并在电动跑步机上以五种速度进行多达五次、每次 6 分钟的步行。
在自由生活条件下，两种设备之间存在高度但非绝对的一致性（组内相关系数=0.983），并且模型 7164 加速度计的输出明显更大（p<0.01），导致两种设备之间存在 7.0%的差异。跑步机行走条件表明，这种加速度计输出之间的差异基于慢走速度，在这些速度下存在统计学上显著（p<0.01）和 30.3%的差异。
在自由生活条件下，ActiGraph 模型 7164 和 GT3X 加速度计不能互换使用，并且两种设备之间的测量差异可能可以用慢走条件下的输出差异来解释。在未来涉及 MS 患者和对照者的研究和临床应用中，研究人员和临床医生应注意 ActiGraph 加速度计以及其他品牌的加速度计之间的输出差异。
