Cheung B, Money K, Sarkar P
Defence and Civil Institute of Environmental Medicine, North York, Ontario, Canada.
J Vestib Res. 1996 Nov-Dec;6(6):411-22.
In this study we investigated the vestibular system by recording eye movements in response to voluntary high-frequency head-only movements using the Vestibular Autorotation Test (VAT; Western System Research Inc., Los Angeles, California). Our objective was to evaluate if the VAT could be implemented as one of the screening tests for vestibular integrity in aircrews and potential pilots. We attempted to record horizontal and vertical eye movements using electrooculography and head velocity with calibrated rotational velocity sensors. The gain and phase of the input and output signals were computed by discrete Fourier analysis. Seated subjects were instructed to fixate on a real or imaginary target while making smooth head oscillations about the spinal axis in time to an audible cue from 0.5 to 6.0 Hz/during an 18-second test period. Test trials included two conditions in the light with subjects fixated on a real target (C1) or on an imaginary target on a blank screen (C2); three conditions in the dark in which subjects fixated on an imaginary target (C3), fixated on a remembered LED target in the dark after it was extinguished (C4), or fixated on a real target (C5). All the dark trials were performed after dark adaptation for 30 minutes. We were not able to obtain consistent vertical VOR response (when the subjects oscillated their head about the interaural axis) using the VAT. For horizontal eye movements from 2.0 to just over 4.7 Hz, when subjects fixated on an imaginary target, there was an unexpected and significant increase in the gain of the eye movement velocities in the dark as compared to the gain obtained in the light conditions. In the dark trials, the gain was significantly higher when the subjects fixated on an imaginary target as opposed to a real target. There was no difference in phase among all conditions. This test could potentially serve for preliminary screening for the integrity of the vestibular system as it is noninvasive and of short duration. However, caution must be exercised in controlling various variables. Extensive normative data are needed to properly assess this test as a screening tool for aircrews.
在本研究中，我们使用前庭自动旋转试验（VAT；西方系统研究公司，加利福尼亚州洛杉矶），通过记录对自愿性高频仅头部运动的眼动来研究前庭系统。我们的目的是评估VAT是否可作为机组人员和潜在飞行员前庭完整性的筛查测试之一。我们试图使用眼电图记录水平和垂直眼动，并使用校准的旋转速度传感器记录头部速度。输入和输出信号的增益和相位通过离散傅里叶分析计算得出。在18秒的测试期间，让坐着的受试者在听到0.5至6.0赫兹的可听提示时，围绕脊柱轴进行平滑的头部摆动，同时注视真实或想象中的目标。测试试验包括两种光照条件下的情况，即受试者注视真实目标（C1）或空白屏幕上的想象目标（C2）；三种黑暗条件下的情况，即受试者注视想象目标（C3）、在黑暗中LED目标熄灭后注视记忆中的LED目标（C4）或注视真实目标（C5）。所有黑暗试验均在暗适应30分钟后进行。使用VAT时，我们无法获得一致的垂直VOR反应（当受试者围绕双耳轴摆动头部时）。对于2.0至略高于4.7赫兹水平的眼动，当受试者注视想象目标时，与光照条件下获得的增益相比，黑暗中眼动速度的增益出现了意外且显著的增加。在黑暗试验中，受试者注视想象目标时的增益明显高于注视真实目标时的增益。所有条件下的相位没有差异。由于该测试是非侵入性的且持续时间短，因此有可能用于前庭系统完整性的初步筛查。然而，在控制各种变量时必须谨慎。需要大量的标准数据来正确评估该测试作为机组人员筛查工具的有效性。
