Experimental validation of a clinical indicator of utricular function.

前庭系统负责我们的平衡感，它位于内耳，负责保持姿势，并帮助有机体在头部移动时进行适当的眼球运动。疾病或事故对前庭系统的损害对患者来说是极其虚弱的。我们的研究计划的主要目标是开发前庭系统的简单测试，可用于临床诊断前庭疾病。大多数目前的临床测试只测试前庭系统的一部分，响应角旋转（半规管）。很少有好的测试可以可靠地诊断与感知位置（耳石）有关的问题。来自人类研究的最新证据表明，通过经由位于耳后皮肤表面上的电极递送小电流（电流刺激），发生眼球运动的特征模式。我们的假设是，眼运动的独特模式产生的结果耳石刺激。这个项目的目的是确定这些小电流是如何产生眼球运动的，以及这些眼球运动是否真的是由耳石介导的。为了确定这些类型的反应背后的生理学，我们无法在人类中进行这些实验。因此，我们目前的计划将使用豚鼠的行为和生理实验来测试我们的假设，电流刺激和耳石功能。这项工作的意义在于，它将导致一种新的方式来评估人类前庭系统的重力感应部分的功能，这似乎是唯一重要的平衡问题的患者。

The vestibular system is responsible for our sense of balance, it is located in the inner ear and is responsible for maintaining posture and helping an organism to make appropriate eye movements when the head moves. Damage to the vestibular system by disease or accident is extremely debilitating for a patient. A chief goal of our research program is to develop simple tests of the vestibular system that can be used in the clinic to diagnose vestibular disorders. Most present clinical tests only test the part of the vestibular system that responds to angular rotations (the semicircular canals). There are few good tests that can reliably diagnose problems concerned with sensed position (the otoliths). Recent evidence from human studies has shown that by delivering small electrical currents (galvanic stimulation) via electrodes located on the surface of the skin behind the ears, a characteristic pattern of eye movement occurs. Our hypothesis is that the distinctive pattern of eye movement produced is a result of otolith stimulation. The aim of this project is to determine exactly how these small currents produce the eye movements and if these eye movements are in fact mediated by the otoliths. To determine the physiology that underlies these types of responses we are unable to conduct these experiments in humans. Our present program will therefore use both behavioural and physiological experiments on guinea pigs to test our hypotheses about galvanic stimulation and otolith function. The significance of this work lies in that it will lead to a new way of evaluating the function of the gravity sensing part of the human vestibular system which appear to be uniquely important for patients with balance problems.