Impact of Hearing Impairment on the Source Generators of Auditory Evoked Potentials

听觉诱发电位在评估听觉脑干的超阈值编码能力方面越来越受欢迎。因为这些聚集的群体反应包含了来自大量听觉神经纤维的同步信息，它们在诊断噪声诱导的耳蜗神经病变方面特别有希望。耳蜗神经病变是一种新发现的听力缺陷，它影响了听觉神经纤维的数量和类型，听觉神经纤维可用于向听觉脑干发出强大的声音信号。尽管听觉诱发电位在文献中有很好的描述，但对其来源产生器或其与单个神经元电生理的关系知之甚少。此外，耳蜗神经病变如何与研究充分的外毛细胞损失相互作用影响听觉诱发电位尚不清楚。然而，为了开发敏感的诊断工具，研究这些关系是很重要的。在本提案中，我们计划通过开发听觉外围的计算模型来弥合动物生理学和人类应用之间的差距，该模型包括听神经、耳蜗核和下丘的单单元模型，以建立人类听觉诱发电位模型。在研究了不同的听力缺陷组合如何影响持续振幅调制刺激的听觉诱发电位源发生器后，我们计划开发增强听觉系统中时间精细结构和包络表征的信号处理策略。模型模拟和信号处理策略的实验验证是基于正常和听力受损听众的皮层下稳态反应的记录。

Auditory evoked potentials are gaining popularity in assessing supra-threshold coding ability in the auditory brainstem. Because these aggregate population responses contain synchronized information converging from a large number of auditory-nerve fibers, they are particularly promising in diagnostics of noise-induced cochlear neuropathy, a newly discovered hearing deficit that affects the number and types of auditory nerve fibers available for a robust signaling of sound to the auditory brainstem.Even though auditory evoked potentials are well described in the literature, not much is known about their source generators or their relationship to the electrophysiology of single neurons. Additionally, it is not known how cochlear neuropathy interacts with the well-studied outer hair cell loss in affecting auditory evoked potentials. However, with an aim to develop sensitive diagnostic tools it is important to study these relationships. In this proposal, we plan to bridge the gap between animal physiology and human applications via the development of a computational model of the auditory periphery that includes single-unit models of the auditory nerve, cochlear nucleus and inferior colliculus into a model for human auditory evoked potentials. After studying how different combinations of hearing deficits affect the source generators of auditory evoked potentials to sustained amplitude-modulated stimuli, we plan on developing signal-processing strategies that enhance temporal fine structure and envelope representation in the auditory system. Experimental validation of the model simulations and signal-processing strategies is based on recordings of subcortical-steady state responses in normal and hearing-impaired listeners.