Department of Sports Medicine and Human Performance, Westfield State University, Westfield, MA, USA.
Joint Department of Biomedical Engineering, The University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC, USA.
J Appl Biomech. 2023 Nov 14;40(2):122-128. doi: 10.1123/jab.2022-0089. Print 2024 Apr 1.
Multiple sclerosis is a neurodegenerative disease that causes balance deficits, even in early stages. Evidence suggests that people with multiple sclerosis (PwMS) rely more on vision to maintain balance, and challenging balance with optical flow perturbations may be a practical screening for balance deficits. Whether these perturbations affect standing balance in PwMS is unknown. Therefore, the purpose of this study was to examine how optical flow perturbations affect standing balance in PwMS. We hypothesized that perturbations would cause higher variability in PwMS compared with matched controls during standing and that standing balance would be more susceptible to anterior-posterior (A-P) perturbations than medial-lateral (M-L) perturbations. Thirteen PwMS and 13 controls stood under 3 conditions: unperturbed, M-L perturbation, and A-P perturbations. A-P perturbations caused significantly higher A-P trunk sway variability in PwMS than controls, although both groups had similar center-of-pressure variability. Both perturbations increased variability in A-P trunk sway and center of pressure. Trunk variability data supported the hypothesis that PwMS were more susceptible to optical flow perturbations than controls. However, the hypothesis that A-P perturbations would affect balance more than M-L perturbations was partially supported. These results suggest potential for optical flow perturbations to identify balance deficits in PwMS.
多发性硬化症是一种神经退行性疾病，会导致平衡缺陷，即使在早期阶段也是如此。有证据表明，多发性硬化症患者（PwMS）更依赖于视觉来维持平衡，而用光流扰动来挑战平衡可能是一种实用的平衡缺陷筛查方法。这些扰动是否会影响 PwMS 的站立平衡尚不清楚。因此，本研究的目的是研究光流扰动如何影响 PwMS 的站立平衡。我们假设，与匹配的对照组相比，在站立时，扰动会导致 PwMS 的变异性更高，并且站立平衡对前后（A-P）扰动比内侧-外侧（M-L）扰动更敏感。13 名 PwMS 和 13 名对照组在 3 种情况下站立：未受扰、M-L 扰动和 A-P 扰动。A-P 扰动会导致 PwMS 的 A-P 躯干摆动变异性明显高于对照组，尽管两组的压力中心变异性相似。两种扰动都会增加 A-P 躯干摆动和压力中心的变异性。躯干变异性数据支持 PwMS 比对照组更容易受到光流扰动影响的假设。然而，A-P 扰动比 M-L 扰动更能影响平衡的假设仅得到部分支持。这些结果表明，光流扰动有可能识别出 PwMS 的平衡缺陷。
