A Neuromechanical Model of Reduced Dorsiflexor Torque During the Anticipatory Postural Adjustments of Gait Initiation.
A Neuromechanical Model of Reduced Dorsiflexor Torque During the Anticipatory Postural Adjustments of Gait Initiation.
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DOI：
10.1109/tnsre.2018.2874991
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发表时间：
2018-11
期刊：
影响因子：
--
通讯作者：
Hsiao-Wecksler ET
中科院分区：
文献类型：
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作者：
Petrucci MN;Diberardino LA;Mackinnon CD;Hsiao-Wecksler ET
预期姿势调整（APA）先于步态启动和功能，以加速质心向前和朝向初始站立腿。阿帕生成的障碍，例如帕金森病（PD）患者中看到的障碍，可能会影响第一步的质量。跨步腿的背屈肌（胫骨前肌）中的活动的初始爆发是压力中心向后偏移的重要贡献者，该压力中心在阿帕期间加速质心向前。PD患者的胫骨前肌激活可能减少或不存在;然而，这种背屈肌扭矩减少对阿帕产生的神经力学后果尚不完全清楚。步态起始的计算模型，包括神经肌肉系统的组成部分，可以提供额外的见解。在这项研究中，倒立摆模型的身体产生的健康年轻的成年人的数据被用来模拟减少背屈肌扭矩在阿帕步态启动。在背屈肌扭矩降低的各种设置下评估身体前倾角和压力中心，并与PD患者的实验数据进行比较。模型的结果表明，将背屈肌峰值扭矩降低8 Nm可能会改变身体前倾和压力中心偏离其标称轨迹。这些结果可以帮助告知需要从外部设备获得多少扭矩来有效地调节APA以用于步态启动，以及提供对病理学中减少背屈肌扭矩的补偿策略的见解。
Anticipatory postural adjustments (APAs) precede gait initiation and function to accelerate the center of mass forward and towards the initial stance leg. Impairments in APA generation, such as those seen in people with Parkinson’s disease (PD), can impact the quality of the first step. An initial burst of activity in the dorsiflexor muscle (tibialis anterior) of the stepping leg is an important contributor to the posterior excursion of the center of pressure that accelerates the center of mass forward during an APA. Tibialis anterior activation can be diminished or absent in people with PD; however, the neuromechanical consequence of this diminished dorsiflexor torque on APA generation is not fully understood. Computational models of gait initiation that include components of the neuromuscular system may provide additional insight. In this study, an inverted pendulum model of the body generated from healthy young adult data was used to simulate reduced dorsiflexor torque during an APA for gait initiation. Forward body lean angle and center of pressure were assessed over various settings of decreased dorsiflexor torque and compared to experimental data from a person with PD. Results from the model demonstrate that reducing the peak dorsiflexor torque by as little as 8 Nm may alter forward body lean and the center of pressure from their nominal trajectories. These results can help inform how much torque is needed from an external device to effectively modulate APAs for gait initiation, as well as provide insight into compensation strategies for reduced dorsiflexor torque in pathology.