Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands.
Neurorehabil Neural Repair. 2013 Mar-Apr;27(3):230-9. doi: 10.1177/1545968312462070. Epub 2012 Oct 16.
Safe community ambulation requires the capacity to adapt gait to environmental changes on short notice. Reduced adaptability may contribute to an increased risk for falls.
This study investigated gait adaptability in community-dwelling persons poststroke and sought to understand some of the mechanisms of reduced adaptability.
Participants were 25 poststroke persons (Functional Ambulation Categories score 5) and 25 healthy controls of similar age. During treadmill walking, 30 obstacles were suddenly dropped in front of the affected leg or left leg of controls. The participants had to avoid the obstacle by either lengthening or shortening the ongoing stride. The obstacle avoidance success rates were determined. Electromyography activity of bilateral biceps femoris, rectus femoris, tibialis anterior, and gastrocnemius medialis muscles was recorded as well as concomitant knee and hip angle courses and spatial characteristics of the avoiding stride.
Poststroke persons demonstrated markedly decreased obstacle avoidance success rates, most prominently under time pressure. They showed normal avoidance strategies but had delayed and reduced electromyography responses, smaller joint angle deviations from unperturbed walking, and smaller horizontal margins from the foot to the obstacle.
Even in persons who were only mildly affected by stroke, gait adaptability may be reduced, which may place them at risk of falling. Delayed and decreased muscle responses were identified as one possible mechanism with diminished ability to adapt the length of the avoiding stride. Rehabilitation interventions could focus on these impairments.
安全的社区行走需要能够在短时间内适应环境变化的能力。适应性降低可能会增加跌倒的风险。
本研究调查了社区居住的脑卒中患者的步态适应性，并试图了解适应性降低的一些机制。
参与者为 25 名脑卒中后患者（功能性步行分类评分为 5）和 25 名年龄相近的健康对照者。在跑步机上行走时，30 个障碍物突然出现在患腿或对照组的左腿前方。参与者必须通过延长或缩短正在进行的步幅来避开障碍物。确定障碍物回避成功率。记录双侧股二头肌、股直肌、胫骨前肌和腓肠肌内侧肌的肌电图活动，以及同时记录膝关节和髋关节角度轨迹以及避障步的空间特征。
脑卒中患者的障碍物回避成功率明显降低，在时间压力下尤为明显。他们表现出正常的回避策略，但肌电图反应延迟且幅度减小，关节角度偏离无干扰行走的幅度减小，脚到障碍物的水平距离减小。
即使是受脑卒中轻度影响的患者，步态适应性也可能降低，从而增加跌倒的风险。延迟和减少的肌肉反应被确定为一种可能的机制，即无法适应避障步的长度。康复干预可以集中在这些损伤上。
