Tisserand R, Armand S, Allali G, Schnider A, Baillieul S
Univ. Lyon, Université Claude Bernard Lyon 1, IFSTTAR, UMR_T9406, LBMC, 69622 Lyon, France; School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada.
Willy Taillard Laboratory of Kinesiology, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
Hum Mov Sci. 2018 Apr;58:175-184. doi: 10.1016/j.humov.2018.01.012. Epub 2018 Mar 12.
Gait asymmetry and dynamic balance impairments observed in post-stroke individuals increase their risk of fall. Moreover, walking while performing a cognitive task (i.e. dual-task) disturbs the control of balance in post-stroke individuals. Here we investigated the mediolateral dynamic stability in twenty-two community-dwelling participants (12 post-strokes and 10 healthy controls) while walking in single-task (normal gait) and four different dual-tasks (cognitive-motor interference). Positions of the extrapolated center of mass and mediolateral widths of both margin of stability and base of support were extracted from 35 marker trajectories. Post-stroke participants presented larger margin of stability and base of support than controls during single-task (both p < 0.01), with a larger margin of stability on the non-paretic side than on the paretic side at ipsilateral foot-strike (p < 0.05). No significant effect of the dual-task was found between groups. In post-stroke participants, dual-task induced slight modification of the mediolateral stability strategy, as the margin of stability was not different between the two limbs at foot-strike, and significantly reduced the performance in every cognitive task. Post-stroke participants increased their dynamic stability in the frontal plane in single-task by extending their base of support and mainly relying on their non-paretic limb. Under cognitive-motor interference (dual-task), post-stroke participants prioritized dynamic stability over cognitive performance to ensure a safe locomotion. Thus, rehabilitation programs should consider both dynamic balance and dual-task training, even at a chronic delay following stroke, to reduce the risk of fall in post-stroke individuals.
中风患者中观察到的步态不对称和动态平衡障碍会增加其跌倒风险。此外，在执行认知任务（即双任务）时行走会干扰中风患者的平衡控制。在此，我们调查了22名社区居住参与者（12名中风患者和10名健康对照）在单任务（正常步态）和四种不同双任务（认知-运动干扰）行走时的中外侧动态稳定性。从35个标记轨迹中提取了推断质心的位置以及稳定性边缘和支撑面的中外侧宽度。中风患者在单任务期间的稳定性边缘和支撑面比对照组更大（均p<0.01），在同侧足跟着地时，非患侧的稳定性边缘比患侧更大（p<0.05）。两组之间未发现双任务的显著影响。在中风患者中，双任务引起了中外侧稳定性策略的轻微改变，因为在足跟着地时两下肢之间的稳定性边缘没有差异，并且显著降低了每项认知任务的表现。中风患者在单任务中通过扩大支撑面并主要依靠非患侧肢体来提高其在额平面的动态稳定性。在认知-运动干扰（双任务）下，中风患者将动态稳定性置于认知表现之上以确保安全行走。因此，康复计划应考虑动态平衡和双任务训练，即使在中风后的慢性延迟阶段，以降低中风患者的跌倒风险。
