Department of Kinesiology and Health Education, University of Texas at Austin, Austin, TX, USA.
J Biomech. 2012 Jul 26;45(11):1979-86. doi: 10.1016/j.jbiomech.2012.05.006. Epub 2012 May 29.
Falls during walking are a major contributor to accidental deaths and injuries that can result in debilitating hospitalization costs, lost productivity, and diminished quality of life. To reduce these losses, we must develop a more profound understanding of the characteristic responses to perturbations similar to those encountered in daily life. This study addresses this issue by building on our earlier studies that examined mechanical and visual perturbations in the same environment by applying the same continuous pseudo-random perturbations at multiple (3 mechanical, 5 visual) amplitudes. Walking variability during mechanical perturbations increased significantly with amplitude for all subjects and differences as measured by variabilities of step width, COM position, and COM velocity. These parameters were the only ones sensitive to the presence of visual perturbations, but none of them changed significantly with perturbation amplitude. Additionally, visual perturbation effects were far less consistent across participants, with several who were essentially unaffected by visual perturbations at any level. The homogeneity of the mechanical perturbation effects demonstrates that human responses to mechanical perturbations are similar because they are driven by kinetics that require similar corrections that must be made in order to maintain balance. Conversely, responses to visual perturbations are driven by the perceived need to make corrections and this perception is not accurate enough to produce amplitude-related corrections, even for a single participant, nor is this perception consistent across individuals. This latter finding is likely to be relevant to future visual perturbation studies and the diagnosis and rehabilitation of gait and balance disorders.
行走时摔倒会导致意外伤害和死亡，从而产生高昂的住院费用、生产力损失和生活质量下降。为了减少这些损失，我们必须更深入地了解与日常生活中遇到的类似干扰相关的特征反应。本研究通过构建我们早期的研究来解决这个问题，这些研究在相同的环境中检查了机械和视觉干扰，并在多个（3 个机械，5 个视觉）幅度下应用相同的连续伪随机干扰。所有受试者的步宽、质心位置和质心速度的变异性均显示，在机械干扰期间行走的可变性随幅度显著增加。这些参数是唯一对视觉干扰存在敏感的参数，但它们都没有随干扰幅度显著变化。此外，视觉干扰的影响在参与者之间差异很大，一些参与者在任何水平下都基本不受视觉干扰的影响。机械干扰效应的同质性表明，人类对机械干扰的反应是相似的，因为它们是由动力学驱动的，需要进行类似的修正才能保持平衡。相反，对视觉干扰的反应是由感知到需要进行修正驱动的，而这种感知不足以产生与幅度相关的修正，即使对于单个参与者也是如此，而且这种感知在个体之间也不一致。后一种发现可能与未来的视觉干扰研究以及步态和平衡障碍的诊断和康复有关。
