Spectro-temporal interactions in electric and acoustic processing and auditory pe

描述(由申请人提供)：尽管在过去三十年中人工耳蜗(CI)技术和性能取得了巨大进步，但CI的言语感知能力仍然比正常听力(NH)差得多，特别是在嘈杂的背景下。听力受损(HI)的听众也有类似的困难，即使在佩戴助听器后也是如此。这项研究的长期目标是通过更好地了解在具有挑战性的声学环境中促进和限制言语感知的基本机制，通过顺式耳机和助听器来改善听觉和言语感知。第一个目标是研究听觉增强和背景效应--类似于视觉中负的后像和颜色恒定效应。在不同房间、不同说话者和不同声学背景产生的声学差异很大的情况下，这些效果可能有助于使传入的声音“正常化”，并产生感知上的不变性。对于HI或CI听者的这些影响，我们知之甚少。如果可以在CI使用者中测量增强效应和语境效应，结果将提供证据，反对最近基于传出控制耳蜗增益的理论。如果HI和/或CI听者没有表现出增强效果，那么我们的结果将指导新的信号处理方案，这些方案将通过信号处理“重建”感知归一化的重要方面。第二个目的是测试一种假设，即频谱分辨率有助于区分具有不同频谱内容的声音，以及在许多现实世界的情况下，通常在频谱匹配的噪声中衡量语音感知的指标低估了频谱分辨率的重要性，因为在现实世界中，掩蔽声音通常不会与目标声音匹配。然后，我们将根据目标1的发现，研究频谱分辨率和随时间变化的频谱增益之间的相互作用。这一结果将导致开发新的语音感知临床测量方法，提供关于频谱分辨率的静态和动态方面的信息，并预测日常听力条件下的表现。这些措施将被用来指导和验证在目标1下开发的新的信号处理方案。在第二部分，我们将检验“稳定”噪声中固有的时间包络波动在限制CI听者的言语知觉方面发挥重要作用的假设。我们将测量噪声中的语音感知，并将其与宽带掩蔽器中不产生幅度波动的语音感知进行比较。在没有虚假固有噪声波动的情况下，对不同时间调幅频带对语音感知的影响的参数研究将为CI用户提供不同幅度频率对语音掩蔽的相对贡献的估计。总体而言，拟议的工作将进一步加深我们对正常、受损和电听力中频谱和时间处理的动态方面的基础知识，并将导致信号处理中的新方法，有望改善复杂和变化声学背景下听力障碍和CI听者的言语感知。

DESCRIPTION (provided by applicant): Despite tremendous progress in cochlear implant (CI) technology and performance over the past three decades, speech perception through a CI remains considerably poorer than in normal hearing (NH), particularly in noisy backgrounds. Similar difficulties are experienced by hearing-impaired (HI) listeners, even after hearing-aid fitting. The long-term goal of this research is to improve auditory and speech perception via CIs and hearing aids, through a greater understanding of the basic mechanisms that contribute to, and limit, the perception of speech in challenging acoustic environments. The first aim studies auditory enhancement and context effects - similar to the negative afterimage and color constancy effects in vision. These effects may help "normalize" the incoming sound and produce perceptual invariance in the face of the widely varying acoustics produced by different rooms, different talkers, and different acoustic backgrounds. Little is known about these effects in either HI or CI listeners. If enhancement and context effects can be measured in CI users, the results will provide evidence against recent theories based on efferent control of cochlear gain. If HI and/or CI listeners do not exhibit enhancement effects, then our results will guide novel signal processing schemes that will "recreate" important aspects of perceptual normalization through signal processing. The second aim tests the hypothesis that spectral resolution helps segregate sounds with different spectral content, and that the usual measures of speech perception in spectrally matched noise underestimate the importance of spectral resolution in many real-world situations, where masking sounds are not usually matched to target sounds. We will then investigate the interaction between spectral resolution and time-dependent spectral gain changes based on the findings from Aim 1. The results should lead to the development of new clinical measures of speech perception that provide information regarding static and dynamic aspects of spectral resolution, and predict performance in everyday listening conditions. These measures will be used to guide and validate the new signal processing schemes developed under Aim 1. In the second part, we will test the hypothesis that the temporal envelope fluctuations inherent in "steady" noise play an important role in limiting speech perception of CI listeners. We will measure speech perception in noise and compare it to speech perception in broadband maskers that produce no amplitude fluctuations. A parametric study of the effect of different temporal amplitude modulation frequency bands on speech perception, in the absence of spurious inherent noise fluctuations will provide estimates in CI users of the relative contributions of different amplitude frequencies to speech masking. Overall, the proposed work will further our fundamental knowledge about dynamic aspects of spectral and temporal processing in normal, impaired, and electric hearing, and will lead to new approaches in signal processing that hold the promise of improving speech perception for hearing- impaired and CI listeners in complex and varying acoustic backgrounds.