Geiger Daniel W, Eggett Dennis L, Charles Steven K
Department of Mechanical Engineering, Brigham Young University, 435 CTB, Provo, UT 84602, United States.
Department of Statistics, Brigham Young University, 223 TMCB, Provo, UT 84602, United States.
Clin Biomech (Bristol). 2018 Feb;52:117-123. doi: 10.1016/j.clinbiomech.2017.12.003. Epub 2018 Jan 3.
Despite the pervasive and devastating effect of Essential Tremor (ET), the distribution of ET throughout the upper limb is unknown. We developed a method for characterizing the distribution of ET and performed a preliminary characterization in a small number of subjects with ET.
Using orientation sensors and inverse kinematics, we measured tremor in each of the seven major degrees of freedom (DOF) from the shoulder to the wrist while ten patients with mild ET assumed 16 different postures. We described the tremor in each DOF in terms of power spectral density measures and investigated how tremor varied between DOF, postures, gravitational torques, and repetitions.
Our method successfully resulted in tremor measures in each DOF, allowing one to compare tremor between DOF and determine the distribution of tremor throughout the upper limb, including how the distribution changes with posture. In our small number of subjects, we found that the amount of power in the frequency band associated with ET (4-12Hz) was lowest in the shoulder and greatest in the wrist. Similarly, the existence and amplitude of peaks in this band increased from proximal to distal. Although the amount of tremor differed significantly between postures, we did not find any clear patterns with changes in posture or gravitational torque.
This method can be used to characterize the distribution of tremor throughout the upper limb. Our preliminary characterization suggests that the amount of tremor increases in a proximal-distal manner.
尽管特发性震颤（ET）具有广泛且严重的影响，但其在上肢的分布情况尚不清楚。我们开发了一种表征ET分布的方法，并在少数ET患者中进行了初步表征。
使用方向传感器和逆运动学，当10名轻度ET患者采取16种不同姿势时，我们测量了从肩部到腕部七个主要自由度（DOF）中每个自由度的震颤。我们根据功率谱密度测量来描述每个自由度中的震颤，并研究震颤在不同自由度、姿势、重力矩和重复动作之间是如何变化的。
我们的方法成功地得出了每个自由度的震颤测量结果，使人们能够比较不同自由度之间的震颤，并确定上肢震颤的分布情况，包括其分布如何随姿势变化。在我们的少数受试者中，我们发现与ET相关的频段（4-12Hz）中的功率量在肩部最低，在腕部最高。同样，该频段中峰值的存在和幅度从近端到远端增加。尽管不同姿势之间的震颤量有显著差异，但我们没有发现任何与姿势或重力矩变化相关的明确模式。
这种方法可用于表征上肢震颤的分布。我们的初步表征表明，震颤量以近端到远端的方式增加。
