Curthoys I S, Dai M J, Halmagyi G M
Department of Psychology, University of Sydney, N.S.W., Australia.
J Vestib Res. 1990;1(2):199-209.
One index of otolith function is the so-called oculogravic "illusion" that during centrifugal stimulation a small luminous bar, fixed with respect to the observer, appears to be roll-tilted by the same amount that the observer feels to be roll-tilted. Many patients undergoing therapeutic unilateral vestibular nerve section show the illusion symmetrically for left and right roll-tilts prior to the operation, but at testing one week after vestibular nerve section show a large asymmetry: they perceive the illusion when the resultant force is directed toward their intact ear, but they perceive a much reduced illusion when the force is directed toward their operated ear. This roll-tilt perceptual response asymmetry appears similar to the asymmetrical horizontal semicircular canal vestibulo-ocular responses for symmetrical but opposite head accelerations that these same patients exhibit for values of head angular accelerations in the natural range (Ewald's second law), and the present paper suggests that a version of Ewald's second law may apply to the otolithic system: specifically, that there is a response asymmetry for linear accelerations. Anatomical and physiological evidence concerning such an otolithic asymmetry is reviewed.
耳石功能的一个指标是所谓的眼重力“错觉”，即在离心刺激期间，相对于观察者固定的一个小发光条似乎滚动倾斜的角度与观察者感觉自己滚动倾斜的角度相同。许多接受治疗性单侧前庭神经切断术的患者在手术前对于左右滚动倾斜的错觉表现对称，但在前庭神经切断术后一周进行测试时表现出很大的不对称性：当合力指向其完好的耳朵时，他们能感觉到这种错觉，但当合力指向其手术侧耳朵时，他们感觉到的错觉会大大减弱。这种滚动倾斜感知反应的不对称性似乎类似于这些患者在自然范围内的头部角加速度值时，对对称但相反的头部加速度所表现出的不对称水平半规管前庭眼反射（埃瓦尔德第二定律），并且本文提出埃瓦尔德第二定律的一个版本可能适用于耳石系统：具体来说，即对于线性加速度存在反应不对称性。本文回顾了关于这种耳石不对称性的解剖学和生理学证据。
