Tabak S, Collewijn H, Boumans L J, van der Steen J
Department of Physiology, Faculty of Medicine, Erasmus University, Rotterdam, The Netherlands.
Acta Otolaryngol. 1997 Nov;117(6):785-95. doi: 10.3109/00016489709114203.
Vestibulo-ocular reflexes (VOR) were evaluated with a reactive torque helmet that imposed high-frequency oscillation (2-20 Hz) or step displacements of the head in the horizontal plane. The present paper describes the experimental and analytical techniques and the results for normal subjects, which will serve as a baseline for the evaluation of vestibular pathology. For comparison, manually controlled head steps were also applied, as described in the literature. Eye and head movements were recorded with magnetic search coils. Non-vestibular effects were avoided by the use of high stimulus frequencies and the analysis of short time-windows (< 100 msec) after steps. Helmet-imposed steps caused a virtually uniform head acceleration (average magnitude 770 degrees/sec) in the first 90 msec. This resulted in a linear relation between eye and head velocities; the gain and delay of the VOR could be calculated independently from the slope and offset of this relation. Such estimates appear more reliable than those obtained with conventional techniques. Normal subjects had a VOR gain of about 0.9 and a delay of about 5 msec. The results of sinusoidal head oscillation were in agreement with the results for steps. The responses to manually generated head steps agreed in general with those to helmet-induced steps, but because of the non-uniform acceleration they allowed a less exact analysis of function.
使用一种反应性扭矩头盔评估前庭眼反射（VOR），该头盔在水平面内施加高频振荡（2 - 20 Hz）或头部的阶跃位移。本文描述了实验和分析技术以及正常受试者的结果，这些结果将作为评估前庭病理学的基线。为了进行比较，还按照文献中所述应用了手动控制的头部阶跃。使用磁搜索线圈记录眼睛和头部的运动。通过使用高刺激频率和分析阶跃后短时间窗口（< 100毫秒）来避免非前庭效应。头盔施加的阶跃在最初90毫秒内导致头部几乎均匀的加速度（平均大小为770度/秒）。这导致眼睛和头部速度之间呈线性关系；VOR的增益和延迟可以根据该关系的斜率和截距独立计算。这样的估计似乎比用传统技术获得的估计更可靠。正常受试者的VOR增益约为0.9，延迟约为5毫秒。正弦头部振荡的结果与阶跃的结果一致。对手动产生的头部阶跃的反应总体上与对头盔诱导的阶跃的反应一致，但由于加速度不均匀，它们对功能的分析不太精确。
