NORMAL & IMPAIRED TEMPORAL PROCESSING OF COMPLEX SOUNDS

我们的长期目标是制定听觉的定量模型， 在正常和受损的听力感知。这些模型改善了我们的 了解正常和受损的听觉过程。他们还帮助 为听力障碍提供更好的诊断工具 以及更好地帮助听力受损的听众康复。拟议 项目旨在研究听觉系统如何处理时间- 改变激励模式，并形成多频带决策规则， 感知响度、粗糙度和调制模式（包络） 复杂的声音因为这些过程的输入被认为是 从激发模式出发，所提出的工作提供了进一步的 测试的概念，激励模式和多波段决策 规则提供了一个通用的框架， 听力受损模型预测将与心理声学进行比较 在耳蜗受损的强迫选择实验中获得的数据 听众和正常的听众测试在安静和下 等效阈值掩蔽。ETM是通过呈现一个 一种连续的掩蔽器，其频谱形状使其产生的阈值等于 对于那些有缺陷的听众来说。这些实验也将提供一个 一组关于简短的听觉处理的大量急需的数据 振幅波动，这是一个重要的先决条件， 言语的感知。实验的具体目标是： 测试刺激成分的响度贡献 at阈值随阈值而增加，并且即使对于 低于其阈值的组件隔离，响度匹配 将获得之间的纯音和多音复合在安静的 并在两个级别的掩蔽下。2)为了验证时间的假设 响度的积分取决于电平， 内部强度代码，不同音调之间的响度匹配 持续时间将作为电平和频率的函数获得。3)到 测试的假设，即感知的粗糙度的大小是 与响度、粗糙度匹配的时间积分成反比 将获得部分掩蔽的调幅音调之间的 载波音调的电平和频率的函数。4)测试 假设跨通道处理有助于感知 相对快速，部分相关的包络波动，在不同的 频率区域，频率的心理测量函数 识别和粗糙度匹配将获得噪声带 通过对正弦幅度调制的宽带噪声进行滤波而产生。 所有这些实验都是由特定的听觉模型激发的 系统和歧视过程，但不管我们的模型 成功，在拟议项目中获得的数据将大大增加 对我们理解正常和受损的听力， 用于开发和测试处理的通用模型 听觉系统的动态信号。

Our long-term objective is to formulate quantitative models of auditory perception in both normal and impaired hearing. Such models improve our understanding of normal and impaired auditory processes. They also aid significantly in providing better diagnostic tools for hearing Impairment and better rehabilitation of hearing-impaired listeners. The proposed project aims to investigate how the auditory system processes time- varying excitation patterns and forms multiband decision rules to perceive loudness, roughness, and modulation patterns (envelopes) of complex sounds. Because the Input to these processes is conceived as originating from excitation patterns, the proposed work provides further testing of the concept that excitation patterns and multi-band decision rules provide a general framework for quantitative modeling of normal and impaired hearing. Model predictions will be compared to psychoacoustic data obtained in forced-choice experiments with cochlearly impaired listeners and with normal listeners tested in the quiet and under Equivalent-Threshold Masking, ETM. ETM is produced by presenting a continuous masker that is spectrally shaped to produce thresholds equal to those of an impaired listener. These experiments also will provide an extensive set of sorely needed data on auditory processing of brief amplitude fluctuations, which is an important prerequisite for the perception of speech. The specific aims of the experiments are: i) To test the hypothesis that the loudness contribution of stimulus components at threshold increases with threshold and is greater than zero even for components that are below their thresholds in isolation, loudness matches will be obtained between pure tones and multitone complexes in the quiet and under two levels of masking. 2) To test the hypothesis that temporal integration for loudness depends on level and has a simple relation to the internal intensity code, loudness matches between tones of different durations will be obtained as a function of level and frequency. 3) To test the hypothesis that the perceived magnitude of roughness is inversely related to temporal integration for loudness, roughness matches between partially masked amplitude-modulated tones will be obtained as a function of level and frequency of the carrier tones. 4) To test the hypothesis that across-channel processing facilitates the perception of relatively fast, partially correlated envelope fluctuations in different frequency regions, psychometric functions for envelope-frequency discrimination and roughness matches will be obtained with noise bands produced by filtering a sinusoidally amplitude modulated broadband noise. All these experiments are motivated by specific models of the auditory system and discrimination processes in it, but regardless of our models' success, the data obtained in the proposed project will add significantly to our understanding of normal and impaired hearing and will be important for the development and testing of general models for the processing of dynamic signals by the auditory system.