Department of Physical Therapy, Faculty of Rehabilitation Sciences, Tehran University of Medical Sciences, Tehran, Iran.
Gait Posture. 2011 Apr;33(4):651-5. doi: 10.1016/j.gaitpost.2011.02.016. Epub 2011 Mar 31.
Postural instability is a major risk factor of falling in the elderly. It is well documented that postural control may decline while performing a concurrent cognitive task and this effect increases with age. Despite the extensive use of dual tasking in balance assessment protocols, a lack of sufficient reliability information is evident. This study determines the reliability of the postural stability measures in older adults, assessed under single and dual-task conditions and different levels of postural difficulty. Sixteen older adults completed quiet stance postural measurements at three levels of difficulty (rigid surface-eyes open, rigid surface-eyes closed, and foam surface-eyes closed), with or without performing a concurrent backward counting task, in two sessions 1 week apart. Force plate data was used to calculate center of pressure (COP) parameters including mean velocity, phase plane portrait, area (95% confidence ellipse), standard deviation (SD) of amplitude, and SD of velocity. Intraclass correlation coefficient (ICC), standard error of measurement (SEM), coefficient of variation (CV), and minimal metrically detectable change (MMDC) were calculated for each COP measure in all test conditions. Mean velocity, total phase plane, phase plane in ML direction, and SD of velocity in ML direction were the most reliable COP measures across all test conditions. ICC values were consistently higher in ML direction compared with AP direction. In general, velocity-related COP measures in ML direction showed to be highly reliable. Further research may explore the predictive and evaluative value of these COP parameters.
姿势不稳是老年人跌倒的主要危险因素。有大量文献记载，当老年人同时执行认知任务时，其姿势控制能力可能会下降，且这种影响会随年龄增长而增加。尽管在平衡评估方案中广泛使用了双重任务，但明显缺乏足够的可靠性信息。本研究旨在确定在单任务和双重任务条件下以及不同姿势难度水平下，对老年人进行姿势稳定性测量的可靠性。16 名老年人在两次相隔一周的测试中，分别在三种难度水平（刚性表面睁眼、刚性表面闭眼和泡沫表面闭眼）下完成了安静站立姿势测量，同时或不进行向后计数的并发任务。使用力板数据计算了包括平均速度、相平面图像、面积（95%置信椭圆）、振幅标准差和速度标准差在内的中心压力（COP）参数。在所有测试条件下，计算了每个 COP 测量的组内相关系数（ICC）、测量标准误差（SEM）、变异系数（CV）和最小可检测变化量（MMDC）。在所有测试条件下，平均速度、总相平面、ML 方向相平面和 ML 方向速度标准差是最可靠的 COP 测量指标。与 AP 方向相比，ML 方向的 ICC 值始终更高。总体而言，ML 方向与速度相关的 COP 测量指标具有高度可靠性。进一步的研究可能会探索这些 COP 参数的预测和评估价值。
