Auditory analysis and speech recognition

描述（由申请人提供）：本研究计划解决与听力正常和耳蜗听力损失个体的听觉信息感知和语音识别相关的基本问题。实验的目的是在耳蜗的活动过程的框架内测试假设，耳蜗负责听觉的许多基本特性。众所周知，耳蜗功能的下降导致更高的检测阈值和更广泛的调谐在较低的水平。然而，除了这些一般的影响，由于对复杂声音（如语音）以及轻度至中度耳蜗听力损失的个体的非线性影响的知识有限，因此缺乏对减少主动机制的负面后果的透彻理解。一个全面的系列实验计划在两个广泛的目标，以解决关键问题的影响，基底膜的非线性听觉感知和识别的语音。这些目标中的每一个都是由假设驱动的，这些假设在为正常和受损的听觉系统提供生理学上适当的理论基础的框架内检查简单和复杂声音的听觉功能。目的1评估时间掩蔽，增长的掩蔽，抑制音调和语音信号在很宽的范围内的水平，并在调整与增加水平的变化，以测试的假设，即在基底膜响应的非线性的基础上改善语音识别在中等水平的噪声，下降在较高的水平，并减少性能的增益减少耳蜗损伤。目标2措施检测和识别的声音波动的信封和掩蔽的音调和语音波动掩蔽，测试的假设，在基底膜响应的非线性变化的语音和噪声的时间信封随着水平的增加，来自掩蔽波动的好处，并减少性能的增益降低耳蜗损伤。一个长期的目标是发现减少耳蜗听力损失对言语感知的不利影响的基础和方法。更好地了解这些影响是必不可少的，如果个人与耳蜗听力损失，以实现最大的好处，从放大语音在不利的听力条件。

DESCRIPTION (provided by applicant): This research program addresses basic questions related to perception of auditory information and recognition of speech by individuals with normal hearing and cochlear hearing loss. Experiments are designed to test hypotheses within the framework of the active process of the cochlea, which is responsible for many fundamental properties of audition. It is well established that declines in cochlear function result in higher detection thresholds and broader tuning at lower levels. However, beyond these general effects, a thorough understanding of the negative consequences of a reduced active mechanism is lacking due to the limited knowledge of nonlinear effects both for complex sounds such as speech, and also for individuals with mild-to-moderate cochlear hearing loss. A comprehensive series of experiments is planned within two broad aims to address key questions concerning the effects of basilar-membrane nonlinearities on auditory perception and recognition of speech. Each of these aims is driven by hypotheses that examine auditory function for simple and complex sounds within a framework that provides physiologically-appropriate rationales for both the normal and impaired auditory system. Aim 1 assesses temporal masking, growth of masking, and suppression for tonal and speech signals over a wide range of levels, and changes in tuning with increasing level, to test the hypothesis that nonlinearities in the basilar-membrane response underlie improvements in speech recognition in noise at moderate levels, declines at higher levels, and diminished performance where gain is reduced by cochlear impairment. Aim 2 measures detection and recognition of sounds with fluctuating envelopes and masking of tones and speech in fluctuating maskers, to test the hypothesis that nonlinearities in the basilar-membrane response underlie changes in the temporal envelopes of speech and noises with increasing level, the benefit derived from masker fluctuations, and diminished performance where gain is reduced by cochlear impairment. A long-term goal is to discover the bases and means for reducing the detrimental effects of cochlear hearing loss on the perception of speech. A better understanding of these effects is essential if individuals with cochlear hearing loss are to achieve maximum benefit from amplified speech in adverse listening conditions.