Department of Kinesiology and Health, Georgia State University, 125 Decatur St, Suite-137, Atlanta, GA 30303, United States.
Department of Mathematical Sciences, University of Texas at El Paso, El Paso, TX, United States.
Mult Scler Relat Disord. 2019 Oct;35:135-141. doi: 10.1016/j.msard.2019.07.019. Epub 2019 Jul 23.
Perturbation training, built upon motor adaptation and learning, has been increasingly used as a fall prevention paradigm in older adults. This training paradigm involves repeated externally-induced perturbations (like slips) to facilitate the error-driven learning of necessary motor skills for preventing falls. It remains unknown if people with multiple sclerosis can adapt to large-scale slip perturbations, which impedes the application of perturbation training in persons with multiple sclerosis. This study explored whether people with multiple sclerosis can adapt to large-scale repeated gait-slips.
Thirteen individuals with multiple sclerosis (the mean ± standard deviation of the Patient Determined Disability Steps: 2.27 ± 1.42) were exposed unexpectedly to a block of five repeated standard slips while walking on a treadmill. The outcome (fall or recovery) for each slip, as our primary outcome measure, was determined. A battery of secondary variables, including dynamic gait stability and gait parameters, were also calculated. Both primary and secondary variables were compared across trials.
Our participants showed a rapidly reduced slip-fall rate (from 92.3% on the first slip to 30.8% on the fifth, p < 0.001). They mainly adopted proactive, assisted by reactive, strategies to improve dynamic gait stability, thus reducing the risk of slip-falls. The proactive adjustments, including shortened step, reduced foot landing angle, and flexed knee, shifted the center of mass anteriorly to be closer to the base of support. Such changes in center of mass position improved dynamic gait stability before the slip. Dynamic gait stability after the slip was also improved across trials, as a reactive strategy.
With practice, people with multiple sclerosis can adapt to large-scale, high-speed, gait-slips and acquire necessary skills against falls. Such skills primarily involve proactive strategy which is assisted by reactive strategy. The proactive strategy would shift the body's center of mass closer to the base of support, improving dynamic gait stability and reducing falls. Our findings could provide a theoretical foundation for deploying perturbation training to prevent falls in people with multiple sclerosis.
基于运动适应和学习的扰动训练已被越来越多地用作老年人的防跌倒范式。这种训练范式涉及到重复的外部诱发扰动（如滑倒），以促进防止跌倒所需的运动技能的错误驱动学习。目前尚不清楚多发性硬化症患者是否可以适应大规模的滑动扰动，这阻碍了扰动训练在多发性硬化症患者中的应用。本研究探讨了多发性硬化症患者是否可以适应大规模的重复步态滑动。
13 名多发性硬化症患者（患者确定残疾步骤的平均值±标准偏差：2.27±1.42）在跑步机上行走时意外地暴露于 5 次重复标准滑动的块中。我们的主要结果测量是每次滑动的结果（跌倒或恢复）。还计算了一系列次要变量，包括动态步态稳定性和步态参数。比较了主要和次要变量在试验之间的差异。
我们的参与者显示出滑动跌倒率迅速降低（从第一次滑动的 92.3%降至第五次滑动的 30.8%，p<0.001）。他们主要采用主动策略，辅助采用反应策略，以提高动态步态稳定性，从而降低滑动跌倒的风险。主动调整包括缩短步长、减小足着地角度和弯曲膝关节，将质心向前移动，更靠近支撑基础。这种质心位置的变化在滑动前改善了动态步态稳定性。随着试验的进行，动态步态稳定性也得到了改善，这是一种反应策略。
通过实践，多发性硬化症患者可以适应大规模、高速的步态滑动，并获得防止跌倒的必要技能。这些技能主要涉及主动策略，辅助反应策略。主动策略会将身体的质心更靠近支撑基础，从而提高动态步态稳定性并减少跌倒。我们的发现为在多发性硬化症患者中部署扰动训练以预防跌倒提供了理论基础。
