Theoretical Study of Underlying Mechanism of Tremor with Reference to Its External Control

本研究的目的是在参考其外部控制的情况下，提供定量分析震颤的方法。虽然震颤有望提供许多神经学信息，但其潜在的机制尚未从控制理论的角度得到澄清。在此之前，我们提出了包含脊柱和棘上反射的双反射环模型。在本研究中，我们试图通过实验验证该模型，并在此基础上建立估计外部震颤控制效果的方法。通过强迫振荡实验对模型进行了验证。手腕固定在振动器上，用FFT方法测量和分析了手加速度和解调的肌电信号。在加速和解调的肌电信号之间的相位角有系统的变化。基于该模型的仿真结果与实验结果基本吻合。在设计机械载荷或外部反馈控制外震动时，需要得到振动趋势的信息。对于拉普拉斯变换方程中的复变量s= α +jomega，实部α可以变为正或负，分别对应于自激振荡或阻尼振荡。因此，认为α表示振荡的趋势。通过计算作为两个反射回路增益函数的变量，证明了该方法的有效性。

The purpose of this study is to provide the means of analyzing tremor quantitatively with reference to its external control. Although tremor is expected to provide much neurological information, its underlying mechanism has not been clarified from the control-theoretical point of view so far. Previously, we proposed the two-reflex-loop model incorporating the spinal and supraspinal reflexes. In this study, attempts are made to validate the model experimentally and to develop the methodology of estimating the effect of external tremor control based on the model.Forced oscillation experiments are performed to validate the model. The wrist is fixed to a vibrator and hand acceleration and demodulated EMG are measured and analyzed by the FFT method. A systematic change in the phase angle between acceleration and demodulated EMG signals is observed. Results of simulation based on the model agree with the experimental results.In designing external tremor control by mechanical loading or external feedback, information is required of the tendency of oscillation. For the complex variable s=alpha+jomega in Laplace-transformed equations, the real part alpha can become positive or negative, corresponding to self-induced or damped oscillation, respectively. Hence alpha is considered to represent the tendency of oscillation. The effectiveness of this method is demonstrated by calculating the variables as functions of the two reflex loop gains.