Stimulation model and experiments for a vestubular prosthesis.

描述（由申请人提供）：前庭系统的性能可以通过监测眼睛的运动来量化，因为前庭-眼反射（VOR）是通过对实验对象施加旋转运动或直接刺激半规管而激活的。我们实验室研制了一种前庭假体。该设备包含陀螺仪，可以感知三个旋转轴的运动，并能够向连接在设备上的电极提供电刺激脉冲。该装置在龙猫半规管中植入电极的初步测试表明，前庭神经分支之间的距离太窄，无法将干净的刺激信号分别传递到前庭神经的每个目标分支。本项目的目标是建立一种电刺激模式，该模式将为大脑提供一套有意义的前庭信号，尽管非特异性刺激会产生信号串扰。我们将研究电极相互作用问题的两种可能的解决方案，并采用尖峰积分模型来预测刺激训练参数对VOR响应的影响。目的1)电刺激和VOR响应之间的线性关系将允许我们使用完善的3D旋转运动学来处理来自假体的陀螺仪信号，尽管电极相互作用。我们假设电刺激和VOR反应之间的线性关系成立。目的2)低振幅刺激提高了电极特异性，但降低了VOR响应的强度。高刺激率已被证明会引起强烈的VOR反应。我们假设使用以高刺激调制率传递的低幅度刺激脉冲将产生低电极相互作用的强VOR响应。最后，我们将扩展一个生物物理模型，用于预测传递到体感皮层的刺激脉冲序列的感知强度，以达到前庭刺激的目的。我们假设该模型将提供对各种电刺激参数的VOR响应的准确表示。相关性：双侧前庭系统功能障碍对患者有衰弱作用，他们被迫进入慢动作存在，以补偿他们平衡系统的缺乏。本研究探讨了几种技术来实现和增强可植入前庭假体的功能。

DESCRIPTION (provided by applicant): The performance of the vestibular system can be quantified by monitoring the motion of the eyes due to the vestibular-ocular reflex (VOR) as it is being activated by applying a rotation motion to the experimental subject or by directly stimulating the semicircular canals. Our laboratory developed a vestibular prosthesis. This device contains gyroscopes that can sense motion about three axes of rotation and it has the ability to provide electrical stimulation pulses to the electrodes, attached to the device. The initial tests of this device with the electrodes implanted in the semicircular canals of chinchillas indicate that the separation between the branches of the vestibular nerve is too narrow to allow a clean stimulation signal to be delivered separately to each targeted branch of the vestibular nerve. The goal of this project is to establish the electrical stimulation paradigm which would provide a meaningful set of vestibular signals to the brain despite the signal crosstalk due to non-specific stimulation. We will examine two possible solutions to the problem of electrode interaction and adapt a spike integrator model to predict the effect of stimulus train parameters on the VOR response. Aim 1) Linear relationship between electrical stimulation and VOR response would allow us to use well- established 3D rotational kinematics to process the gyroscope signals from the prosthesis, despite electrode interaction. We hypothesize that linear relationships hold true between electrical stimulation and VOR responses. Aim 2) Low amplitude stimulation improves electrode specificity, but decreases the strength of the VOR response. High stimulation rates have been shown to introduce strong VOR response. We hypothesize that using low amplitude stimulation pulses delivered at high stimulation modulation rates will produce strong VOR responses with low electrode interaction. Aim 3) Finally, we will extend a biophysical model developed for predicting perceived intensity of stimulation pulse trains delivered to the somatosensory cortex, for the purposes of vestibular stimulation. We hypothesize that the model will provide accurate representation of VOR response to a wide variety of electrical stimulation parameters. RELEVANCE: Bilateral dysfunction of the vestibular system has debilitating effects on the patients, who are forced into a slow motion existence so as to compensate for the lack of their balance system. This study examines several techniques to enable and enhance the functioning of an implantable vestibular prosthesis.