Vestibular contribution to the control of human upright stance

描述（由申请人提供）：本项目的长期目标是了解来自前庭系统的内耳平衡传感器的运动信息如何有助于人类的平衡控制，并确定前庭电刺激（GVS）可用于恢复前庭功能减弱受试者的有用前庭平衡贡献的程度。长期以来，GVS一直被用于定性地证明前庭对平衡控制的贡献，但缺乏详细的定量理解。工程系统识别方法和建模将被应用于开发GVS作为一种定量工具，用于调查前庭对平衡控制的贡献，并作为一种潜在的假体援助，以提高前庭缺陷受试者的平衡。 拟议的工作有三个具体目标。第一个目标将结合联合收割机实验和建模方法，以：（1）定义来自前庭传感器的运动信息如何有助于平衡控制，（2）确定前庭取向信息如何与来自本体感受、躯体感觉和视觉系统的信息组合，（3）确定组合的感觉信息如何用于产生对施加在多节段身体上的外部扰动的校正响应，以及（4）识别具有双侧前庭损失（BVL）的受试者如何补偿他们的前庭损失。在第一个目标中开发的模型提供了关于控制平衡的机制的定量假设。第二个目标将使用GVS测试的结果来识别GVS诱发的身体摇摆的方面，其不同于通过实际头部运动从前庭感受器的自然激活预期的摇摆。我们将开发一种方法来解释这些差异，然后使用GVS来测试我们基于模型的多节段平衡控制假设是否预测前庭对平衡控制的贡献如何随环境和刺激条件的变化而变化。第三个目标将使用GVS诱发的平衡反应和基于模型的理解的平衡控制系统的识别特性，开发一种方法，使用GVS反馈，基于头部运动的实时测量，操纵前庭的平衡控制的贡献。由于许多BVL受试者对GVS保持敏感，因此存在实时GVS反馈以恢复BVL受试者中对平衡控制的功能有用的前庭贡献的可能性。 成功完成拟议的实验将提供新的见解前庭对人体平衡控制和机制，补偿前庭损失的贡献。使用GVS反馈准确操纵前庭运动信息的方法的发展将有助于未来前庭对运动任务的贡献的调查，并可能有助于前庭假体的开发。 公共卫生相关性：平衡障碍使受试者易受福尔斯伤害，并增加与跌倒相关的发病率和死亡率。拟议的研究将提供关于神经系统如何使用来自内耳前庭传感器的方向信息进行平衡控制的更好理解，将确定限制前庭补偿的因素，并将研究恢复前庭功能缺陷受试者平衡的前庭控制的方法。

DESCRIPTION (provided by applicant): The long-term goals of this project are to understand how motion information from the inner-ear balance sensors of the vestibular system contributes to the control of balance in humans and to determine the extent to which galvanic vestibular stimulation (GVS) can be used to restore a useful vestibular contribution to balance in subjects with diminished vestibular function. GVS has long been used to demonstrate qualitatively a vestibular contribution to balance control, but a detailed quantitative understanding is lacking. Engineering system-identification methods and modeling will be applied to develop GVS as a quantitative tool for investigating the vestibular contribution to balance control and as a potential prosthetic aid to enhance balance in subjects with vestibular deficits. The proposed work has three specific aims. The first aim will combine experimental and modeling methods to: (1) define how motion information from vestibular sensors contributes to balance control, (2) determine how vestibular orientation information is combined with information from proprioceptive, somatosensory, and visual systems, (3) determine how combined sensory information is used to generate corrective responses to external perturbations imposed on a multi-segmental body, and (4) identify how subjects with bilateral vestibular loss (BVL) compensate for their vestibular loss. Models developed in the first aim provide quantitative hypotheses about mechanisms controlling balance. The second aim will use results from GVS tests to identify aspects of GVS-evoked body sway that differ from sway expected from the natural activation of vestibular receptors by actual head motion. We will develop a method that accounts for these differences, and then use GVS to test whether our model-based hypotheses of multi-segmental balance control predict how the vestibular contribution to balance control changes as a function of environmental and stimulus conditions. The third aim will use the identified characteristics of GVS-evoked balance responses and a model-based understanding of the balance control system to develop a method that uses GVS feedback, based on real-time measures of head motion, to manipulate the vestibular contribution to balance control. Because many BVL subjects remain sensitive to GVS, the potential exists for real-time GVS feedback to restore a functionally useful vestibular contribution to balance control in BVL subjects. Successful completion of the proposed experiments will provide new insights into the vestibular contribution to human balance control and mechanisms that compensate for vestibular loss. The development of methods for accurately manipulating vestibular-motion information using GVS feedback will facilitate future investigations of the vestibular contribution to motor tasks and could potentially contribute to the development of a vestibular prosthesis. PUBLIC HEALTH RELEVANCE: Balance disorders leave a subject vulnerable to falls and the increased morbidity and mortality associated with falling. The proposed research will provide a greater understanding about how the nervous system uses orientation information from the inner ear's vestibular sensors for balance control, will determine what limits vestibular compensation, and will investigate a method for restoring some level of vestibular control of balance in subjects with deficient vestibular function.