NONSTATIONARY PROPERTIES OF POSTURAL SWAY
NONSTATIONARY PROPERTIES OF POSTURAL SWAY
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DOI：
10.1016/0021-9290(93)90004-x
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发表时间：
1993-04-01
影响因子：
2.4
通讯作者：
FREEDMAN, W
中科院分区：
文献类型：
--
作者：
CARROLL, JP;FREEDMAN, W
静止站立时的姿态摆动通常被认为是一个平稳的随机过程。我们通过调查三名受试者姿势摆动的平均值和方差的时间不变性来检验这一假设。用测力板在三种情况下测量摇摆：受试者双脚站立，睁眼；受试者双脚站立，闭眼；受试者单脚站立，睁眼。数据收集在1分钟内完成。在每个测试条件下，为每个受试者收集了超过50分钟的数据。对每个受试者和条件的所有运行的数据进行平均。数据中发现了一些趋势。此外，在关于趋势的二阶矩中，最初存在暂时性的增长。一阶矩和二阶矩的瞬时变化通常在前20个S阶段就消失了。根据这些发现，我们可以否定姿势摆动是一个平稳过程的假设。结果表明，常用的姿势摆动参数方法要么需要改变，要么需要重新解释。
Postural sway during quiet stance is usually assumed to be a stationary stochastic process. We tested this assumption by investigating the time invariance of the average value and variance of the postural sway of three subjects. The sway was measured with a force plate under three conditions: subject standing on two feet with eyes open; subject standing on two feet with eyes closed; and subject standing on one foot with eyes open. Data were collected in 1 min runs. More than 50 min of data were collected for each subject under each test condition. The data were averaged across all runs for each subject and condition. Trends were found to be present in the data. In addition, there were initial transient increases in the second-order moments about the trends. The transient changes in first- and second-order moments usually disappeared during the first 20 s. In light of these findings, we can reject the hypothesis that postural sway is a stationary process. The results imply that the usual methods to parameterize postural sway have to be either changed or reinterpreted.