Gait variability and stability measures: Minimum number of strides and within-session reliability
Gait variability and stability measures: Minimum number of strides and within-session reliability
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DOI：
10.1016/j.compbiomed.2014.04.001
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发表时间：
2014-07-01
影响因子：
7.7
通讯作者：
Stagni, R.
中科院分区：
文献类型：
--
作者：
Riva, F.;Bisi, M. C.;Stagni, R.
背景：文献中提出了几种方法来量化躯干加速度的步态变异性/稳定性。由于执行差异会影响产出，因此执行参数的可靠性评估和标准化仍然是一个问题。本研究的目的是评估所需的步幅和11个变异性/稳定性measures.Method的会话内的可靠性的最低数量：10名健康参与者走在一条直线上，在自选的速度穿着两个同步的三轴惯性测量单元。基于步幅时间计算五个变异性度量，即标准差、变异系数、方差不一致性、非平稳指数和Poincare图。六个稳定性措施计算的基础上，即最大Floquet乘数，短期/长期的李雅普诺夫指数，递归量化分析，多尺度熵，谐波比和指数的和谐。根据四分位数范围/平均值比获得每项测量所需的最小步幅数和会话内可靠性。措施被分为五个类别（即优秀，良好，平均，差，非常差）的基础上，他们的reliability.Results：所需的步幅的数量，以获得一个可靠的措施是一般大于那些常规使用。变异性措施表现出平均到较差的可靠性，而稳定性措施范围从优秀到非常差的reliability.Conclusion：躯干加速度的递归量化分析和多尺度熵表现出良好的可靠性和合理的所需步幅数。根据这些结果，在评估跌倒风险时应考虑这些措施。(C)2014爱思唯尔有限公司版权所有。
Background: Several methods are proposed in the literature for the quantification of gait variability/stability from trunk accelerations. Since outputs can be influenced by implementation differences, reliability assessment and standardization of implementation parameters are still an issue. The aim of this study is to assess the minimum number of required strides and the within-session reliability of 11 variability/stability measures.Method: Ten healthy participants walked in a straight line at self-selected speed wearing two synchronized tri-axial Inertial Measurement Units. Five variability measures were calculated based on stride times namely Standard deviation, Coefficient of variation, Inconsistency of variance, Nonstationary index and Poincare plot. Six stability measures were calculated based on trunk accelerations namely Maximum Floquet multipliers, Short term/long term Lyapunov exponents, Recurrence quantification analysis, Multiscale entropy, Harmonic ratio and Index of harmonicity. The required minimum number of strides and the within-session reliability for each measure were obtained based on the interquartile range/mean ratio. Measures were classified in five categories (namely excellent, good, average, poor, and very poor) based on their reliability.Results: The number of strides required to obtain a reliable measure was generally larger than those conventionally used. Variability measures showed average to poor reliability, while stability measures ranged from excellent to very poor reliability.Conclusion: Recurrence quantification analysis and multiscale entropy of trunk accelerations showed excellent reliability and a reasonable number of required strides. Based on these results, these measures should be taken into consideration in the assessment of fall risk. (C) 2014 Elsevier Ltd. All rights reserved.