Background

People poststroke often walk with a spatiotemporally asymmetric gait, due in part to sensorimotor impairments in the paretic lower extremity. Although reducing asymmetry is a common objective of rehabilitation, the effects of improving symmetry on balance are yet to be determined.

Objective

We established the concurrent validity of whole-body angular momentum as a measure of balance, and we determined if reducing step length asymmetry would improve balance by decreasing whole-body angular momentum.

Methods

We performed clinical balance assessments and measured whole-body angular momentum during walking using a full-body marker set in a sample of 36 people with chronic stroke. We then used a biofeedback-based approach to modify step length asymmetry in a subset of 15 of these individuals who had marked asymmetry and we measured the resulting changes in whole-body angular momentum.

Results

When participants walked without biofeedback, whole-body angular momentum in the sagittal and frontal plane was negatively correlated with scores on the Berg Balance Scale and Functional Gait Assessment supporting the validity of whole-body angular momentum as an objective measure of dynamic balance. We also observed that when participants walked more symmetrically, their whole-body angular momentum in the sagittal plane increased rather than decreased.

Conclusions

Voluntary reductions of step length asymmetry in people poststroke resulted in reduced measures of dynamic balance. This is consistent with the idea that after stroke, individuals might have an implicit preference not to deviate from their natural asymmetry while walking because it could compromise their balance. Clinical Trials Number: NCT03916562.

中文翻译：

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使用生物反馈来减少步长不对称会损害人们中风后的动态平衡

背景

中风后的人经常以时空不对称的步态行走，部分原因是麻痹下肢的感觉运动障碍。虽然减少不对称是康复的共同目标，但改善对称性对平衡的影响还有待确定。

客观的

我们建立了全身角动量作为平衡度量的同时有效性，我们确定减少步长不对称是否会通过降低全身角动量来改善平衡。

方法

我们使用在 36 名慢性中风患者样本中设置的全身标记进行临床平衡评估并测量行走期间的全身角动量。然后，我们使用基于生物反馈的方法来修改其中 15 名具有明显不对称性的个体中的步长不对称性，并测量由此产生的全身角动量变化。

结果

当参与者在没有生物反馈的情况下行走时，矢状面和额面的全身角动量与伯格平衡量表和功能步态评估的分数呈负相关，支持全身角动量作为动态平衡的客观测量的有效性。我们还观察到，当参与者走得更对称时，他们在矢状面上的全身角动量增加而不是减少。

结论

中风后人们自愿减少步长不对称导致动态平衡测量的减少。这与中风后个人可能有一种隐含的偏好是一致的，即在行走时不偏离他们的自然不对称，因为这可能会损害他们的平衡。临床试验编号：NCT03916562。