Temporal weighting of interaural time and level differences

描述（由申请人提供）：本研究将研究听者如何在不同类型的双耳线索-耳间时间差（ITD）和耳间水平差（ILD）-以及随着时间的推移联合收割机听觉空间信息，以便更好地理解混响环境中空间听觉的动态过程。ITD和ILD提供了一组主要的线索，使听众能够在空间中定位声音并隔离竞争声源。在理想情况下，这两个线索彼此一致，提供了关于听觉空间的冗余信息，但回声和混响会随着时间的推移而扭曲这些线索，从而降低定位和语音理解。虽然正常的双耳系统通过强调声音的鲁棒方面（例如开始时的ITD）进行补偿，但老化，听力受损或使用人工耳蜗的听众在回声和混响存在的情况下仍然会遇到困难。确定这些听觉处理缺陷的具体性质是困难的，因为对正常听力的听众中起作用的补偿机制知之甚少。过去的研究已经调查了空间灵敏度如何随着声音的时间过程而变化（从而强调声音起始），但一个关键问题仍然没有答案：这些变化是否特定于ITD和/或ILD的处理，或者它们是否反映了线索随时间推移而组合的方式？拟议的研究的具体目标解决这个问题，映射的时间过程中的听众的敏感性ITD，ILD，以及两者的组合。听众将判断声音的空间位置与时变ITD和/或ILD，和多元回归将被用来衡量这些判断ITD和/或ILD的依赖性。回归系数将用于构建时间加权函数（TWF），其说明了ITD和ILD随时间整合的神经机制的动态。目标进一步解决TWF是否在涉及和不涉及明显定位的任务之间变化（例如，辨别与指向声音）。由于许多患者人群（老年人、听力受损者、人工耳蜗植入者）在嘈杂和混响环境中听力受损，因此，对听力正常者处理回声和混响的机制的更好理解将改善（a）听觉处理缺陷的理论描述，以及（B）助听器和人工耳蜗植入物中信号处理的算法。具体而言，将敏感度的时间过程映射到ITD和ILD可以指导数字信号处理资源的分布，以最有效地保留相关的空间信息，并淡化潜在的误导信息。

DESCRIPTION (provided by applicant): This research will examine how listeners combine auditory spatial information across different types of binaural cues-interaural time differences (ITD) and interaural level differences (ILD)-and over time in order to better understand the dynamic processes underlying spatial hearing in reverberant environments. ITD and ILD provide the major set of cues that allow listeners to localize sounds in space and to segregate competing sound sources. In ideal situations, the two cues agree with one another, providing redundant information about auditory space, but echoes and reverberation distort these cues over time, thereby degrading localization and speech understanding. Whereas the normal binaural system compensates by emphasizing robust aspects of the sound (such as ITD at onset), listeners who are aging, hearing-impaired, or using cochlear implants continue to experience difficulty in the presence of echoes and reverberation. Identifying the specific nature of these auditory processing deficits is difficult because so little is known about the compensatory mechanisms at work in normal-hearing listeners. Past research has investigated how spatial sensitivity changes over the time-course of a sound (thereby emphasizing sound onsets), but a key question remains unanswered: Are these changes specific to the processing of ITD and/or ILD, or do they reflect the manner in which the cues are combined over time? The specific aims of the proposed study address this question by mapping the time-course of listeners' sensitivity to ITD, ILD, and combinations of the two. Listeners will judge the spatial positions of sounds with time-varying ITD and/or ILD, and multiple regression will be used to measure the dependence of those judgments on ITD and/or ILD. Regression coefficients will be used to construct temporal weighting functions (TWFs) that illustrate the dynamics of neural mechanisms for integration of ITD and ILD over time. The aims further address whether TWFs vary between tasks that do and do not involve overt localization (e.g., discriminating vs. pointing to sounds). Because a number of patient populations (aging, hearing impaired, cochlear implant users) are impaired when listening in noisy and reverberant environments, an improved understanding of the mechanisms that allow normal-hearing individuals to deal with echoes and reverberation will improve (a) theoretical descriptions of auditory processing deficits, and (b) algorithms for signal processing in hearing aids and cochlear implants. Specifically, mapping the time-course of sensitivity to ITD and ILD could guide the distribution of digital signal-processing resources to most effectively preserve relevant spatial information and de-emphasize potentially misleading information.