Hirvonen T P, Aalto H, Pyykkö I
Department of Otorhinolaryngology, University Central Hospital of Helsinki, Finland.
Auris Nasus Larynx. 2000 Jan;27(1):23-6. doi: 10.1016/s0385-8146(99)00044-9.
The vestibulo-ocular reflex (VOR) stabilizes gaze during head movements by producing compensatory eye movements. Gain of the VOR can be defined as the difference between the eye and corresponding head movement amplitudes. The objective of the study was to compare the gain of postoperative vestibular schwannoma (VS) patients with that of healthy controls.
The gain of 19 vestibular schwannoma (VS) patients and 100 healthy controls was measured with a head autorotation test (HART) in the five frequency bands of 1-5 Hz. It was computed as the ratio of the amplitude of the eye position signal to the amplitude of the head position signal. The mean gain was compared between the VS patients and healthy subjects in each frequency band by using an analysis of variance with statistical significance pre-defined as P < 0.05.
The HART was abnormal in 58% of the VS patients, whose mean gains in the five frequency bands of 1-5 Hz were 0.85, 0.79, 0.72, 0.64 and 0.60, respectively. The mean gains of the VS patients were significantly (P < 0.05) smaller than those of the controls in all the frequency bands.
The deficit of the VOR gain seems to prevail in more than a half of postoperative VS patients, although this inaccuracy of compensatory eye movements may not lead to the occurrence of any symptoms. However, in these patients a potential threat to gaze stability exists.
前庭眼反射（VOR）通过产生代偿性眼球运动在头部运动期间稳定注视。VOR增益可定义为眼球与相应头部运动幅度之间的差值。本研究的目的是比较前庭神经鞘瘤（VS）术后患者与健康对照者的增益。
采用头部自转试验（HART）在1-5Hz的五个频段测量了19例前庭神经鞘瘤（VS）患者和100例健康对照者的增益。计算方法为眼球位置信号幅度与头部位置信号幅度之比。通过方差分析比较VS患者和健康受试者在每个频段的平均增益，并将统计学显著性预先定义为P<0.05。
58%的VS患者HART异常，其在1-5Hz五个频段的平均增益分别为0.85、0.79、0.72、0.64和0.60。在所有频段，VS患者的平均增益均显著低于对照组（P<0.05）。
虽然这种代偿性眼球运动的不准确可能不会导致任何症状的出现，但超过一半的VS术后患者似乎存在VOR增益缺陷。然而，在这些患者中，注视稳定性存在潜在威胁。
