Okada T, Grunfeld E, Shallo-Hoffmann J, Bronstein A M
MRC Human Movement and Balance Unit, Institute of Neurology, National Hospital for Neurology and Neurosurgery, London, UK.
Brain. 1999 Jul;122 ( Pt 7):1293-303. doi: 10.1093/brain/122.7.1293.
A technique is described for the assessment of vestibular sensation. The two main goals of the study were (i) to compare the perception of angular velocity with the eye velocity output of the vestibulo-ocular reflex and (ii) to study vestibular function in patients with congenital nystagmus; this was needed since most previous studies, based on eye movement recordings, have been inconclusive. Subjects indicated their perceived angular velocity by turning by hand a wheel connected to a tachometer. The vestibular stimuli used consisted of sudden deceleration from rotation at a constant horizontal velocity of 90 degrees /s ('stopping' responses). Eye movements were recorded simultaneously with electro-oculography. In normal subjects the perceived angular velocity decayed from the moment of deceleration in an exponential fashion. The mean time constant of sensation decay was approximately 16 s. Eye movement velocity decayed with a similar exponential trajectory (time constant 16 s). Congenital nystagmus patients showed markedly shortened vestibular sensation (mean time constant 7 s). The following conclusions can be drawn: (i) the similarity of the eye velocity and perceptual responses suggests that these two systems receive a vestibular signal which has been similarly processed; (ii) the time constant of the responses indicates that this vestibular signal probably originates in the same brainstem 'velocity storage' integrator; (iii) the technique described is useful for clinical assessment of vestibular function, particularly in patients with ocular motility disorders; (iv) patients with congenital nystagmus have short vestibular time constants, which is probably due to changes induced in velocity storage processing by the persistent retinal image motion present in these patients.
本文描述了一种评估前庭感觉的技术。该研究的两个主要目标是：（i）比较角速率感知与前庭眼反射的眼速输出；（ii）研究先天性眼球震颤患者的前庭功能；之所以需要这样做，是因为以往大多数基于眼动记录的研究尚无定论。受试者通过手动转动与转速计相连的轮子来表明其感知到的角速率。所使用的前庭刺激包括以90度/秒的恒定水平速度旋转后突然减速（“停止”反应）。同时用电眼图记录眼动。在正常受试者中，感知到的角速率从减速时刻起呈指数方式衰减。感觉衰减的平均时间常数约为16秒。眼动速度以类似的指数轨迹衰减（时间常数16秒）。先天性眼球震颤患者的前庭感觉明显缩短（平均时间常数7秒）。可以得出以下结论：（i）眼速和感知反应的相似性表明这两个系统接收到经过类似处理的前庭信号；（ii）反应的时间常数表明该前庭信号可能起源于同一个脑干“速度存储”积分器；（iii）所描述的技术可用于前庭功能的临床评估，特别是对于有眼球运动障碍的患者；（iv）先天性眼球震颤患者的前庭时间常数较短，这可能是由于这些患者中持续存在的视网膜图像运动引起的速度存储处理变化所致。
