Norman K E, Edwards R, Beuter A
Laboratoire de neuroscience de la cognition, Université du Québec à Montréal, Canada.
J Neurosci Methods. 1999 Oct 15;92(1-2):41-54. doi: 10.1016/s0165-0270(99)00091-6.
Precise kinematic measurements of tremor have historically been obtained using accelerometers. However, current technology permits precise measurements in velocity and displacement. The primary advantage of velocity recording is that only one step of integration or differentiation is required for either displacement or acceleration. A method is presented of measuring finger tremor using a laser system that transduces velocity precisely. Measurements of postural finger tremor thus obtained were compared to those simultaneously obtained from a laser system that transduces displacement, from an accelerometer and from surface electromyography (EMG) of the extensor digitorum communis. A range of amplitude and frequency content was obtained by testing control subjects and subjects with Parkinson's disease. The velocity transducer showed excellent correspondence of amplitude and frequency measurement with the displacement transducer. Measures of absolute and relative amplitude correlated well (r > or = 0.96 in amplitude measures in displacement, velocity and acceleration), and high coherence was found throughout the frequency range of interest. Measurements by the accelerometer generally showed poorer correspondence with those of the other instruments. EMG measurements showed good correspondence in some trials but poorer correspondence in others, attributed to the low level of muscle activity required in the task. Precise kinematic measurements appear to be highly sensitive to neuromotor impairment.
震颤的精确运动学测量在历史上一直是通过加速度计来实现的。然而，当前的技术能够实现对速度和位移的精确测量。速度记录的主要优势在于，对于位移或加速度而言，仅需一步积分或微分运算。本文介绍了一种使用能精确转换速度的激光系统来测量手指震颤的方法。将由此获得的姿势性手指震颤测量结果，与同时从能转换位移的激光系统、加速度计以及指总伸肌的表面肌电图（EMG）所获得的测量结果进行比较。通过对对照组受试者和帕金森病患者进行测试，获取了一系列的振幅和频率范围。速度传感器在振幅和频率测量方面与位移传感器显示出极佳的一致性。绝对振幅和相对振幅的测量结果相关性良好（在位移、速度和加速度的振幅测量中，r≥0.96），并且在整个感兴趣的频率范围内都发现了高相干性。加速度计的测量结果通常与其他仪器的测量结果一致性较差。EMG测量在某些试验中显示出良好的一致性，但在其他试验中一致性较差，这归因于该任务所需的肌肉活动水平较低。精确的运动学测量似乎对神经运动损伤高度敏感。
