IEEE Trans Neural Syst Rehabil Eng. 2018 Apr;26(4):839-846. doi: 10.1109/TNSRE.2018.2816953.
Focal vibration is an effective intervention for the management of spasticity. However, its neuromechanical effects, particularly how tonic vibration reflex is induced explicitly, remain implicit. In this paper, we utilize a high-speed camera and a method of image processing to quantify the muscle vibration rigorously and disclose the neuromechanical mechanism of focal vibration. The vibration of 75 Hz is applied on the muscle belly of the biceps brachii and muscle responses are captured by a high-speed camera in profile. The muscle silhouettes are identified by the Canny edge detector to represent the stretch of muscle fibers, and the consistency between the muscle stretch and profile deformation has been confirmed by the magnetic resonance imaging in advance. Oscillations of muscle points discretized by pixels are identified by the fast Fourier transformation, respectively, and results demonstrate that focal vibration stretches muscle by producing muscle waves. Specifically, each point vibrates harmonically, and, given the linear phase modulation with transverse position, the muscle vibration propagates as traveling waves. The propagation of muscle waves is associated with muscle stretch, whose frequency is the same with the vibrator due to the curved baseline, and thus induces the tonic vibration reflex via spinal circuits.
焦点振动是一种有效的痉挛管理干预措施。然而，其神经机械效应，特别是如何明确引发紧张性振动反射，仍然不明确。在本文中，我们利用高速摄像机和图像处理方法来严格量化肌肉振动，并揭示焦点振动的神经机械机制。在肱二头肌的肌腹上施加 75Hz 的振动，通过高速摄像机以侧位捕捉肌肉反应。通过 Canny 边缘检测识别肌肉轮廓以代表肌纤维的拉伸，并且通过磁共振成像预先确认了肌肉拉伸和轮廓变形之间的一致性。通过快速傅里叶变换分别识别像素离散化的肌肉点的振动，结果表明焦点振动通过产生肌肉波来拉伸肌肉。具体而言，每个点都以谐波方式振动，并且由于横向位置的线性相位调制，肌肉振动以行波的形式传播。肌肉波的传播与肌肉拉伸有关，其频率与由于弯曲基线而与振动器相同，因此通过脊髓回路引起紧张性振动反射。
