Spatial and Temporal Control Contribute to Step Length Asymmetry During Split-Belt Adaptation and Hemiparetic Gait.
Spatial and Temporal Control Contribute to Step Length Asymmetry During Split-Belt Adaptation and Hemiparetic Gait.
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DOI：
10.1177/1545968314567149
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发表时间：
2015-09
影响因子：
4.2
通讯作者：
Torres-Oviedo G
中科院分区：
文献类型：
--
作者：
Finley JM;Long A;Bastian AJ;Torres-Oviedo G
步长不对称(SLA)是卒中后步态的共同特征。虽然二语习得通常被认为是空间缺陷，但它可能是由于脚相对于身体的放置位置(空间策略)、两脚击打之间的时间(步长策略)或身体相对于脚的速度(步速策略)的差异造成的。本研究的目的是确定这些策略对二语习得的相对贡献。我们开发了一个分析模型，将SLA解析为独立的步长位置、步长和步速贡献。当25名健康参与者的自然对称步态在以2：1或3：1带速比移动的分带式跑步机上受到扰动时，该模型得到了验证。然后，我们应用经过验证的模型来量化15名中风幸存者在以他们自己选择的速度行走时的步位、步时和步速对二语习得的贡献。无论皮带速比如何，都可以通过对派生贡献进行求和来准确预测SLA。尽管在我们的卒中幸存者样本中，对SLA的贡献有很大的不同，但步位的贡献倾向于与其他两个相反--可能是为了将总体SLA最小化。我们的结果表明，改变脚的位置或改变肢体间的时机可以作为代偿性策略，以减少中风幸存者的总体SLA。这些结果可能使临床医生和研究人员能够识别患者特定的步态异常，并相应地个性化他们的治疗方法。
Step length asymmetry (SLA) is a common hallmark of gait post-stroke. Though conventionally viewed as a spatial deficit, SLA can result from differences in where the feet are placed relative to the body (spatial strategy), the timing between foot-strikes (step time strategy), or the velocity of the body relative to the feet (step velocity strategy). The goal of this study was to characterize the relative contributions of each of these strategies to SLA. We developed an analytical model that parses SLA into independent step position, step time, and step velocity contributions. This model was validated by reproducing SLA values for twenty-five healthy participants when their natural symmetric gait was perturbed on a split-belt treadmill moving at either a 2:1 or 3:1 belt-speed ratio. We then applied the validated model to quantify step position, step time, and step velocity contributions to SLA in fifteen stroke survivors while walking at their self-selected speed. SLA was predicted precisely by summing the derived contributions, regardless of the belt-speed ratio. Although the contributions to SLA varied considerably across our sample of stroke survivors, the step position contribution tended to oppose the other two – possibly as an attempt to minimize the overall SLA. Our results suggest that changes in where the feet are placed or changes in interlimb timing could be used as compensatory strategies to reduce overall SLA in stroke survivors. These results may allow clinicians and researchers to identify patient-specific gait abnormalities and personalize their therapeutic approaches accordingly.