Reynard Fabienne, Terrier Philippe
Clinique romande de réadaptation SUVACare, Av. Gd-Champsec 90, 1951, Sion, Switzerland.
Exp Brain Res. 2015 Apr;233(4):1031-40. doi: 10.1007/s00221-014-4177-5. Epub 2014 Dec 23.
While vision obviously plays an essential role in orienting and obstacle avoidance, its role in the regulation of dynamic balance is not yet fully understood. The objective of this study was to assess dynamic stability while blindfolded, under optimal conditions that minimized the fear of falling. The hypothesis was that visual deprivation could be compensated for by using other sensory strategies to stabilize gait. One hundred healthy adults (aged 20-69 years) participated in the study. They were previously accustomed to blindfolded treadmill walking wearing a safety harness. Their preferred walking speeds (PWS) were assessed with eyes open (PWSEO) and with eyes closed (blindfolded, PWSEC). Three five-minute tests were performed: (A) normal walking at PWSEO, (B) blindfolded walking at PWSEC, and (C) normal walking at PWSEC. Trunk acceleration was measured with a lightweight inertial sensor. Dynamic stability was assessed by using (1) acceleration root mean square (RMS), which estimates the variability of the signal, and hence, the smoothness of the trunk movement and (2) local dynamic stability (LDS), which reflects the efficiency of the motor control to stabilize the trunk. Although walking at PWSEC with eyes open (comparing conditions A and C) had a slight impact on gait stability (relative difference: RMS +4 %, LDS -5 %), no destabilizing effect of visual deprivation (B vs. C, RMS -4 %, LDS -1 %) was observed. Therefore, it is concluded that when reassuring conditions are offered to individuals while walking, they are able to adopt alternative sensory strategies to control dynamic equilibrium without the help of vision.
虽然视觉在定向和避障中显然起着至关重要的作用，但其在动态平衡调节中的作用尚未完全明确。本研究的目的是在尽量减少跌倒恐惧的最佳条件下，评估蒙眼时的动态稳定性。假设是视觉剥夺可以通过使用其他感觉策略来稳定步态得到补偿。100名健康成年人（年龄在20 - 69岁之间）参与了这项研究。他们之前习惯了戴着安全带在跑步机上蒙眼行走。分别在睁眼（PWSEO）和闭眼（蒙眼，PWSEC）状态下评估他们的偏好步行速度（PWS）。进行了三项五分钟的测试：（A）以PWSEO正常行走，（B）以PWSEC蒙眼行走，以及（C）以PWSEC正常行走。使用轻型惯性传感器测量躯干加速度。通过以下方式评估动态稳定性：（1）加速度均方根（RMS），它估计信号的变异性，进而反映躯干运动的平稳性；（2）局部动态稳定性（LDS），它反映运动控制稳定躯干的效率。尽管睁眼以PWSEC行走（比较条件A和C）对步态稳定性有轻微影响（相对差异：RMS +4%，LDS -5%），但未观察到视觉剥夺的不稳定作用（B与C比较，RMS -4%，LDS -1%）。因此，得出结论，当在行走时为个体提供安心的条件时，他们能够在无需视觉帮助的情况下采用替代感觉策略来控制动态平衡。
