Department of Rehabilitation, Himeji Central Hospital, 2-36, Shikama-ku Miyake, Himeji City, Hyogo 672-8501, Japan; Department of Rehabilitation, National Hospital Organization Wakayama Hospital (Current Address), 1138 Wada Mihama-cho, Hidaka-gun, Wakayama 644-0044, Japan.
Faculty of Rehabilitation, Kansai Medical University, 18-89 Uyamahigashicho, Hirakata City, Osaka 573-1136, Japan.
J Electromyogr Kinesiol. 2022 Jun;64:102660. doi: 10.1016/j.jelekin.2022.102660. Epub 2022 Apr 15.
Lower extremity force steadiness has been shown to decrease with aging and neuromotor dysfunction and to be associated with physical function and fall. Although patients with Parkinson's disease (PD) experience decreased force steadiness, whether the extent of force steadiness differs according to target force or whether this steadiness is associated with postural control remain unclear. Therefore, this study aimed to compare the force steadiness while steadily exerting low and moderate levels of knee extensor force between individuals with and without PD and to examine the association between force steadiness and postural instability against mechanical perturbation in PD.
A total of 33 patients with PD (mean age, 71.7 years) and 33 healthy controls (72.2 years) participated in this study. Participants with PD were classified into postural stability or instability groups based on the Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale motor exam item 12. Participants performed steady task of the knee isometric extension at two levels (10% and 50% of maximal voluntary contraction [MVC]).
Force steadiness at 10% MVC was lower in postural instability group than that in the control and postural stability groups (P < 0.05) after adjusting for age, sex, and body mass index, whereas it was not significantly different at 50% MVC among the three groups.
These results suggest that the knee extensor force steadiness is affected in patients with PD having postural instability against mechanical perturbation during low intensity force exertion and is not affected regardless of the presence of postural instability during moderate intensity force exertion.
下肢力量稳定性已被证明随年龄增长和神经运动功能障碍而降低，并与身体功能和跌倒有关。虽然帕金森病（PD）患者的力量稳定性降低，但力量稳定性的程度是否因目标力量而异，或者这种稳定性是否与姿势控制有关尚不清楚。因此，本研究旨在比较 PD 患者和健康对照组在稳定施加低水平和中等水平膝关节伸肌力量时的力量稳定性，并检查 PD 患者在机械干扰下的姿势不稳定与力量稳定性之间的关系。
共有 33 名 PD 患者（平均年龄 71.7 岁）和 33 名健康对照者（72.2 岁）参与了这项研究。根据运动障碍协会赞助的帕金森病统一评分量表运动检查项目 12 的修订版，将 PD 患者分为姿势稳定或不稳定组。参与者在两个水平（最大自主收缩 [MVC] 的 10%和 50%）进行膝关节等长伸展的稳定任务。
在调整年龄、性别和体重指数后，姿势不稳定组在 10% MVC 时的力量稳定性低于对照组和姿势稳定组（P<0.05），而在 50% MVC 时三组之间无显著差异。
这些结果表明，在低强度力量施加期间，患有对机械干扰的姿势不稳定的 PD 患者的膝关节伸肌力量稳定性受到影响，而在中等强度力量施加时，无论是否存在姿势不稳定，力量稳定性都不受影响。
