Dynamic Effects in Peripheral Auditory Processing

描述(由申请人提供)：这项建议的长期目标是加深我们对正常和受损听力的外周听觉处理和传出或自上而下影响的知觉后果的理解。该项目有三个主要目标。目的1是对人类内侧橄榄耳蜗区(MOC)传出系统对基底膜(BM)增益和压缩的假想效应进行行为学和生理学评估，并利用前向掩蔽技术确定它们在单个频率通道内的时间加工的结果。这些措施将在听力正常的听者和感音神经性听力损失的听者中进行。目的2将通道内时间加工研究扩展到跨通道时间加工，研究周边滤波和传出控制对复杂声音时频加工的影响。工作假设是，随着听力损失，BM过滤的变化会导致BM沿线相对潜伏期的变化，而这并不能完全由神经可塑性来补偿。跨声道时间同步在我们在复杂环境中感知分离相互竞争的声音的能力中起着至关重要的作用，因此在嘈杂和具有挑战性的声学背景中，感知同步的中断可能尤其有害。这一目标下的实验将根据时间分辨率和敏锐度以及对同步的主观判断来衡量跨频率的声音的时间知觉，以检验跨频率的时间知觉随着听力损失而变化的假设。目标3将利用在目标1和目标2中获得的基本心理物理知识，并将其应用于在嘈杂背景下的语音感知。在跨频率施加系统延迟的情况下，将在稳定噪声、波动噪声和单人干扰的情况下测量句子的语音可理解性。安静状态下的言语感知已经被证明对跨频率的时间不同步具有显著的健壮性。我们的工作假设是，时间不同步，无论是通过信号处理施加的，还是作为听力损失的结果，都会在噪声环境中产生更严重的语音清晰度缺陷，在这种情况下，需要对目标和掩蔽者进行感知分离。这些结果将进一步加深我们对传出刺激是如何影响外周听觉处理的理解，以及由于听力损失而导致的外周处理的变化如何影响我们对声音的感知和我们在具有挑战性的声学环境中的沟通能力。了解外周听觉处理如何影响声道内和跨声道的时间知觉，可能会导致用于助听器的新的信号处理算法，以补偿听力损失引起的跨声道时间变化。 与公共健康相关：这项提案中的工作旨在加深我们对大脑“自上而下”的影响如何影响内耳处理声音的方式，以及这种处理如何影响听力正常的人和听力有困难的人感知声音和言语的方式的理解。更好地理解听力损失导致的耳朵变化是如何影响知觉的，应该会带来设计助听器的新的和改进的方法。

DESCRIPTION (provided by applicant): The long-term goal of this proposal is to further our understanding of the perceptual consequences of peripheral auditory processing and efferent, or top-down, effects in normal and impaired hearing. The project has three main aims. Aim 1 is to provide behavioral and physiological estimates of the hypothesized effects of the medial olivocochlear (MOC) efferent system on basilar-membrane (BM) gain and compression in humans, and to determine their consequences for temporal processing within individual frequency channels using forward masking. These measures will be undertaken in both normal-hearing listeners and listeners with sensorineural hearing loss. Aim 2 extends the investigation from within-channel to across-channel temporal processing to study the effects of peripheral filtering and efferent control on the spectro-temporal processing of complex sounds. The working hypothesis is that changes in BM filtering with hearing loss lead to changes in the relative latencies along the BM, which are not fully compensated by neural plasticity. Across-channel temporal synchrony plays a crucial role in our ability to perceptually segregate competing sounds in complex environments, so a disruption of perceived synchrony may be particularly detrimental in noisy and challenging acoustic backgrounds. Experiments under this aim will measure the temporal perception of sounds across frequency, in terms of temporal resolution and acuity, as well as in terms of subjective judgments of synchrony to test the hypothesis that across-frequency temporal perception changes with hearing loss. Aim 3 will take the basic psychophysical knowledge gained in Aims 1 and 2 and apply it to speech perception in noisy backgrounds. Speech intelligibility of sentences will be measured in steady noise, fluctuating noise, and single- talker interference in conditions where systematic delays are imposed across frequency. Speech perception in quiet has been shown to be remarkably robust to temporal asynchronies across frequency. Our working hypothesis is that temporal asynchronies, whether imposed through signal processing or as a result of hearing loss, will produce much more serious deficits in speech intelligibility in noisy situations, where perceptual segregation of the target from the masker is required. The results will further our understanding of how peripheral auditory processing is affected by efferent stimulation, and how changes in peripheral processing due to hearing loss affect our perception of sound and our ability to communicate in challenging acoustic environments. Understanding how peripheral auditory processing influences within- and across-channel temporal perception may lead to novel signal-processing algorithms for hearing aids that compensate for the across-channel temporal changes induced by hearing loss. PUBLIC HEALTH RELEVANCE: The work in this proposal aims to further our understanding of how "top-down" influences from the brain affect the way sound is processed in the inner ear, and how that processing affects the way people with normal hearing and people with hearing difficulties perceive sound and speech. Improved understanding of how perception is affected by changes in the ear due to hearing loss should lead to new and improved methods for designing hearing aids.