Age-related changes in compensatory stepping in response to unpredictable perturbations
Age-related changes in compensatory stepping in response to unpredictable perturbations
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DOI：
10.1093/gerona/51a.6.m289
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发表时间：
1996-11-01
影响因子：
5.1
通讯作者：
Maki, BE
中科院分区：
文献类型：
--
作者：
McIlroy, WE;Maki, BE
背景资料。最近的研究强调了补偿性步进对保持稳定性的重要性，以及对这种反应的控制的空间和时间要求。与年龄相关的控制踏步的变化可能会极大地影响跌倒的风险。本研究比较了健康老年人和年轻人对不可预测的姿势扰动的代偿性阶跃反应的特点。一个移动平台被用来意外地扰乱14名天真、活跃和活动的受试者的直立姿势(5名年龄在22岁到28岁之间，9名年龄在65岁到81岁之间)。对前10个随机试验(5个向前，5个向后)进行了评估，以便将重点放在对相对较新的扰动的反应上。受试者的行为不受约束。用测力板和运动学测量来评估短时间(600毫秒)平台平移引起的反应。受试者参与了98%的试验。虽然老年人不太可能在抬脚前进行侧向预期姿势调整，但在两个年龄组中，摆动腿卸载的开始往往是同时开始的。年轻人和老年人在第一步反应的许多其他特征上有显著的相似之处。尽管有这种相似之处，老年受试者采取额外措施恢复稳定的可能性是前者的两倍(老年人试验的63%)。此外，在老年受试者中，额外的步骤通常是为了保持侧向稳定性，而年轻人很少表现出这种倾向。鉴于支持基数变化作为一种维持稳定的战略的功能意义，以及目前显示的与年龄有关的差异，针对不可预测的干扰保持稳定的能力的评估，以及发生或放置多个步骤等具体措施，可能被证明是跌倒风险的重要预测指标，也是评估或制定预防跌倒的干预策略的重要结果。
Background. Recent studies highlight the importance of compensatory stepping to preserve stability, and the spatial and temporal demands placed on the control of this reaction. Age-related changes in the control of stepping could greatly influence the risk of falling. The present study compares, in healthy elderly and young adults, the characteristics of compensatory stepping responses to unpredictable postural perturbations.Methods. A moving platform was used to unpredictably perturb the upright stance of 14 naive, active and mobile subjects (5 aged 22 to 28 and 9 aged 65 to 81). The first 10 randomized trials (5 forward and 5 backward) were evaluated to allow a focus on reactions to relatively novel perturbations. The behavior of the subjects was not constrained. Forceplate and kinematic measures were used to evaluate the responses evoked by the brief (600 msec) platform translation.Results. Subjects stepped in 98% of the trials. Although the elderly were less likely to execute a lateral anticipatory postural adjustment prior to foot-lift, the onset of swing-leg unloading tended to begin at the same time in the two age groups. There was remarkable similarity between the young and elderly in many other characteristics of the first step of the response. In spite of this similarity, the elderly subjects were twice as likely to take additional steps to regain stability (63% of trials for elderly). Moreover, in elderly subjects, the additional steps were often directed so as to preserve lateral stability, whereas the young rarely showed this tendency.Conclusions. Given the functional significance of base-of-support changes as a strategy for preserving stability and the age-related differences presently revealed, assessment of the capacity to preserve stability against unpredictable perturbation, and specific measures such as the occurrence or placement of multiple steps, may prove to be a significant predictor of falling risk and an important outcome in evaluating or developing intervention strategies to prevent falls.