Dynamical simulation of speech cooperative articulation by muscle linkages
Dynamical simulation of speech cooperative articulation by muscle linkages
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DOI：
10.1007/s00422-004-0510-6
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发表时间：
2004-11-01
影响因子：
1.9
通讯作者：
Honda, M
中科院分区：
文献类型：
--
作者：
Ito, T;Gomi, H;Honda, M
不同类型的发音器官，如上下嘴唇、下颌和舌头，在言语产生中精确协调。基于对使用上唇和下唇产生摩擦辅音的扰动研究，已经提出增加上唇和下颌之间的肌肉连接的刚度有利于保持嘴唇之间的收缩区域（Gomi等人，2002）。这一假说对于研究言语运动控制的机制，即言语运动协调是否受机械阻抗的控制至关重要。为了验证这一假设，在目前的研究中，我们进行了动态模拟的嘴唇补偿运动的肌肉联动模型的基础上，然后评估补偿运动的性能。利用口轮匝肌上级（OOS）的肌电（EMG）信号，通过肌电-刚度的时间变换（二阶时滞动力学），获得了肌链刚度的时间模式，并通过实验确定了变换参数。动态模拟使用刚度估计从经验肌电图成功地再现了上唇代偿性关节的时间轮廓。此外，估计的刚度变化显着有助于再现功能调制的补偿反应。这一结果支持了机械阻抗高度有助于组织嘴唇和下巴之间的协调的想法。对运动指令进行编程，不仅可以在每个咬合架中产生运动，还可以调节咬合架之间的机械阻抗，以实现言语运动控制的鲁棒协调。
Different kinds of articulators, such as the upper and lower lips, jaw, and tongue, are precisely coordinated in speech production. Based on a perturbation study of the production of a fricative consonant using the upper and lower lips, it has been suggested that increasing the stiffness in the muscle linkage between the upper lip and jaw is beneficial for maintaining the constriction area between the lips (Gomi et al. 2002). This hypothesis is crucial for examining the mechanism of speech motor control, that is, whether mechanical impedance is controlled for the speech motor coordination. To test this hypothesis, in the current study we performed a dynamical simulation of lip compensatory movements based on a muscle linkage model and then evaluated the performance of compensatory movements. The temporal pattern of stiffness of muscle linkage was obtained from the electromyogram (EMG) of the orbicularis oris superior (OOS) muscle by using the temporal transformation (second-order dynamics with time delay) from EMG to stiffness, whose parameters were experimentally determined. The dynamical simulation using stiffness estimated from empirical EMG successfully reproduced the temporal profile of the upper lip compensatory articulations. Moreover, the estimated stiffness variation significantly contributed to reproduce a functional modulation of the compensatory response. This result supports the idea that the mechanical impedance highly contributes to organizing coordination among the lips and jaw. The motor command would be programmed not only to generate movement in each articulator but also to regulate mechanical impedance among articulators for robust coordination of speech motor control.