Background

Postural control is impaired in older adults, as evidenced from greater variability of the center of pressure (COP) during postural tasks. Although COP variability associates with low-frequency COP oscillations (<1 Hz) in young adults, it remains unknown if the age-associated increase in COP variability relates to greater low-frequency COP oscillations.

Research question

Do low-frequency oscillations contribute to greater postural sway (center of pressure (COP) variability) in older adults when attempting to voluntarily maintain posture in a forward leaning position compared to young adults?

Methods

Seven young (25.7 ± 4.8) and seven older (71.0 ± 7.0) adults performed a postural lean forward task and attempted to match a COP target in the anterior-posterior direction as steady as possible. We quantified the COP variability as the standard deviation (SD) of COP displacements in the anterior-posterior and medial-lateral directions and quantified the frequency modulation of COP as the power in COP displacement spectra from 0-1 Hz.

Results

We found that older adults had significantly greater anterior-posterior SD of COP (p = 0.027) and power below 0.5 Hz (p = 0.048) than young adults, but power from 0.5-1 Hz was similar (p = 0.083). In contrast, the medial-lateral SD of COP (p = 0.5) and power from 0-1 Hz (p = 0.228) was similar for the two age groups. For both the anterior-posterior and medial-lateral direction, the SD of COP was related to low frequency oscillations below 0.5 Hz.

Significance

For the first time, we show that the age-associated increase in postural variability relates to greater COP oscillations below 0.5 Hz.

中文翻译：

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与年龄相关的姿势变异性增加与更大的低频压力振荡中心有关

背景

老年人的姿势控制受到损害，这从姿势任务期间压力中心 (COP) 的更大变化中可以看出。尽管 COP 变异性与年轻人的低频 COP 振荡（<1 Hz）有关，但与年龄相关的 COP 变异性增加是否与更大的低频 COP 振荡有关仍然未知。

研究问题

与年轻人相比，当老年人试图自愿保持前倾姿势时，低频振荡是否会导致更大的姿势摇摆（压力中心 (COP) 变化）？

方法

七名年轻 (25.7 ± 4.8) 和七名年长 (71.0 ± 7.0) 成年人执行了体位前倾任务，并试图在前后方向上尽可能稳定地匹配 COP 目标。我们将 COP 变异性量化为 COP 位移在前后方向和内外侧方向的标准偏差 (SD)，并将 COP 的频率调制量化为 0-1 Hz 的 COP 位移谱中的功率。

结果

我们发现老年人的 COP 前后 SD (p = 0.027) 和低于 0.5 Hz (p = 0.048) 的功率显着高于年轻人，但 0.5-1 Hz 的功率相似 (p = 0.083)。相比之下，COP 的内侧-外侧 SD (p = 0.5) 和 0-1 Hz 的功率 (p = 0.228) 在两个年龄组中相似。对于前后方向和内侧方向，COP 的 SD 与 0.5 Hz 以下的低频振荡有关。

意义

我们第一次表明，与年龄相关的姿势变异性增加与低于 0.5 Hz 的更大 COP 振荡有关。