Harley Clare, Wilkie Richard M, Wann John P
Leeds Institute of Molecular Medicine, University of Leeds, UK.
Gait Posture. 2009 Apr;29(3):428-32. doi: 10.1016/j.gaitpost.2008.10.063. Epub 2008 Dec 11.
Older adults have been shown to trip on obstacles despite taking precautions to step carefully. It has been demonstrated in dual-task walking that age-related decline in cognitive and attentional mechanisms can compromise postural management. This is yet to be substantiated during obstacle negotiation when walking. Forty-six healthy volunteers (aged 20-79 years) stepped over obstacles in their path whilst walking and performing a verbal fluency task. Using 3D kinematic analysis we compared obstacle crossing during single-task (obstacle crossing only) and dual-task (obstacle crossing with verbal task) conditions. We grouped the participants into three age groups and examined age-related changes to cognitive interference on obstacle crossing. During dual-task trials, the 20-29 and 60-69 groups stepped closer to the obstacles prior to crossing, increased vertical toe-obstacle clearance, and had reduced gait variability. In these two groups there was a small dual-task decrease in verbal output. The 70-79 group applied similar dual-task stepping strategies during pre-crossing. However, during crossing they showed reduced vertical toe-to-obstacle clearance and increased variability of obstacle-to-heel distance. Additionally, this group did not show any significant change to verbal output across trials. These results suggest that with advanced age, increased cognitive demands are more likely to have a detrimental impact on motor performance, leading to compromised safety margins and increased variability in foot placement. We conclude that younger adults utilise a posture-preserving strategy during complex tasks but the likelihood of this strategy being used decreases with advanced age.
研究表明，尽管老年人采取了小心行走的预防措施，但仍会在障碍物上绊倒。在双任务行走中已经证明，与年龄相关的认知和注意力机制衰退会影响姿势管理。在行走时越过障碍物的过程中，这一点还有待证实。46名健康志愿者（年龄在20 - 79岁之间）在行走并执行语言流畅性任务时跨过路径中的障碍物。我们使用三维运动学分析比较了单任务（仅跨越障碍物）和双任务（跨越障碍物并执行语言任务）条件下的跨越障碍物情况。我们将参与者分为三个年龄组，并研究了与年龄相关的跨越障碍物时认知干扰的变化。在双任务试验中，20 - 29岁组和60 - 69岁组在跨越之前会更靠近障碍物，增加垂直脚趾与障碍物的间距，并降低步态变异性。在这两组中，语言输出有小幅的双任务下降。70 - 79岁组在跨越前应用了类似的双任务跨步策略。然而，在跨越过程中，他们的垂直脚趾与障碍物的间距减小，障碍物与脚跟距离的变异性增加。此外，该组在各试验中语言输出没有任何显著变化。这些结果表明，随着年龄增长，认知需求增加更有可能对运动表现产生不利影响，导致安全裕度降低和脚部放置的变异性增加。我们得出结论，年轻人在复杂任务中会采用保持姿势的策略，但随着年龄增长，使用这种策略的可能性会降低。
