Bilateral cochlear implants:Physiology and psychophysics

双耳听力对于准确的声音定位和听出感兴趣的声音是必不可少的 在竞争的声源中，这些双耳优势是一个重要的激励因素 双侧人工耳蜗植入术越来越多。在这项申请中，来自三个实验室的研究人员 在马萨诸塞州眼耳医院，麻省理工学院和波士顿大学联手提出了- 寻求确定最佳刺激配置的综合心理物理、神经和建模研究 用于在双侧植入物中有效地编码双耳信息。主要的关注点是耳间时间。 差异(ITD)是因为ITD是声音定位的主要线索，并且因为双耳在 检测依赖于ITD。心理物理实验将在植入人体的病人身上进行。 与Clarion设备进行双边连接。神经实验将在耳聋的麻醉猫身上进行。 双侧植入耳壳内电极阵列。将进行单单元和多单元录音 从下丘(IC)可以获得关于双耳特性的大量信息 神经元。为了明确和定量地检验我们对实证结果的理解，我们将 还使用双耳处理模型来预测IC反应和心理物理能力 电刺激反应中的CH_(Cr)、inticm_nf和itorv神经活动。S的具体目标是(1) 确定时间包络和精细结构在ITD编码中的相对有效性 听力，(2)确定1TD敏感度如何依赖于耳蜗区耳间位置的差异 刺激电极，(3)确定在噪声中检测信号是否具有双耳优势 双侧刺激。这些实验的一个重要目标是测试一种新的处理策略，该策略 寻求改善刺激波形在听觉时间放电模式中的表示 通过使用持续的、高速率、去同步的脉冲串作为载波波形。总的来说，这些 研究将提供有关影响双耳相互作用的刺激参数的基本知识 电听力，并有可能导致新的处理器设计专门适用于双侧耳蜗 植入物。

Binaural hearing is essential for accurate sound localization and for hearing out sounds of interest among competing sound sources, and these binaural advantages are an important motivating factor for the increasing number of bilateral cochlear implants. In this application, investigators from three laboratories at the Massachusetts Eye and Ear Infirmary, MIT, and Boston University join together to propose closely- integrated psychophysical, neural and modeling studies that seek to identify the best stimulus configurations for effectively encoding binaural information in bilateral implants. The primary focus is on interaural time differences (ITD) because ITD is a dominant cue for sound localization, and because binaural advantages in detection depend on ITD. The psychophysical experiments will be conducted in human patients implanted bilaterally with Clarion devices. The neural experiments will be conducted in deafened, anesthetized cats implanted bilaterally with intracochlear electrode arrays. Single and multi-unit recordings will be made from the inferior colliculus (IC), for which a great deal of information is available on binaural properties of neurons. In order to explicitly and quantitatively test our understanding of the empirical results, we will also use models of binaural processing to predict both IC responses and psychophysical abilities from ch_¿cr,inticm_ nf anditorv nerve activity in responm to electric stimulation. The s_cific aims are to (1) letermine the relative effectiveness of temporal envelope and fine structure for ITD coding in electric hearing, (2) determine how 1TD sensitivity depends on interaural disparities in cochlear locations of the stimulating electrodes, (3) determine whether there is a binaural advantage for signal detection in noise with bilateral stimulation. An important goal of these experiments will be to test a novel processing strategy that seeks to improve the representation of the stimulus waveform in temporal discharge patterns of auditory neurons by using an ongoing, high-rate, desynchronizing pulse train as the carrier waveform. Overall, these studies will provide basic knowledge about the stimulus parameters that influence binaural interactions in electric hearing and are likely to lead to new processor designs specifically adapted to bilateral cochlear implants.