INTENSITY DLS AND MASKING IN NORMAL AND IMPAIRED HEARING

我们的长期目标是理解听觉 该系统将允许对音调的感知进行定量建模， 噪声和正常和受损听力的言语。此类模型 对于理解正常的听觉过程很重要， 用于改善听力受损听众的诊断和康复。 拟议的项目旨在获得心理声学数据， 进一步测试的概念，激励模式和多波段 决策规则可以为定量建模提供一般框架 正常和受损的听力。在21，2AFC实验的基础上， 受损，和面具正常的听众，拟议的项目将 建立一个坚实的基础，完善我们的兴奋模式模型， 强度歧视和测试有关的一些假设， 在这个模型和其他模型中的决策过程。具体目标是：（1） 为了验证跨频率整合的差异 对于检测短和长音复合体， 心理测量功能，心理测量功能将被测量为 检测被掩蔽的短音和长音以及音调复合体。(2)测试 假设短音调的阈值低于预期 复合体依赖于跨多个通道的同步活动， 将测量短纯音和复合音的掩蔽阈值 在包络处具有各种相位关系的分量音调 峰(3)为了验证听觉神经的相位锁定 可以帮助检测具有长持续时间的音调、安静环境中的阈值 和下掩蔽将比较长和短突发的音调， 在几个频率上冻结的窄带噪声。(4)测试 假设持续时间对水平区分的影响取决于 在激励模式的宽度上，电平辨别阈值 将测量音调和音调复合体，部分被 陷波噪声掩蔽器。(5)为了验证这一假设， 屏蔽信号是基于在同等的最佳选择中的活动 加权频率选择性信道，检测概率函数 （单刺激条件，COSS）将测量纯音 以及在固定或随机条件下的18音调复合。的信号 将被由24个临界带组成的均匀掩蔽噪声掩蔽 水平随机变化的大范围噪音。条件心理测量 这样得到的函数提供了决策规则的直接估计 用于每个信号和收听条件。(6)为了检验这一假设 听众在水平辨别实验中的决定是基于 关于跨区间激发能级的最优加权和 频率选择性信道的差异，COSS功能将 为多音调复合体的电平辨别力而测量的， 随机抖动被施加到每个分量。这些数据将增加 这对我们理解正常和受损的听力有很大的帮助， 将是重要的发展和测试模型的 听觉系统关于听觉系统如何整合 信息跨 渠道，虽然这种能力是至关重要的，我们的看法，几乎 所有的声音。

Our long-term objective is to reach an understanding of the auditory system that will allow quantitative modeling of the perception of tones, noise, and speech in both normal and impaired hearing. Such models are important for understanding normal auditory processes and provide a basis for improving diagnosis and rehabilitation of hearing-impaired listeners. The proposed project aims to obtain psychoacoustic data that will allow further tests of the concept that excitation patterns and multiband decision rules may provide a general framework for quantitative modeling of normal and impaired hearing. Based on 21,2AFC experiments in normal, impaired, and masked-normal listeners, the proposed project will establish a firm basis for refining our excitation-pattern model of intensity discrimination and testing a number of hypotheses related to the decision process In this and other models. The specific aims are: (1) To test the hypothesis that differences in across-frequency integration for detection of brief and long tone complexes reflect different psychometric functions, psychometric functions will be measured for detection of masked brief and long tones and tone complexes. (2) To test the hypothesis that lower-than-expected thresholds for brief tone complexes depends on synchronous activity across a number of channels, masked thresholds will be measured for brief tone bursts and tone complex with the component tones in various phase relationships at the envelope peak. (3) To test the hypothesis that phase-locking of the auditory nerve may aid detection of tones with long durations, thresholds in the quiet and under masking will be compared for long and short bursts of tones and frozen narrow-band noises at several frequencies. (4) To test the hypothesis that the effect of duration on level discrimination depends on the width of the excitation pattern, level discrimination thresholds will be measured for tones and tone complexes partially masked by notched-noise maskers. (5) To test the hypothesis, that detection of masked signals is based on activity in an optimum selection of equally weighted frequency-selective channels, detection-probability functions (Conditional On a Single Stimulus, COSS) will be measured for pure tones and an 18-tone complex in either fixed or random conditions. The signals will be masked by uniformly masking noise composed of 24 critical-band wide noises whose levels vary randomly. The conditional psychometric functions thus obtained provide direct estimates of the decision rules used for each signal and listening condition. (6) To test the hypothesis that listeners' decision in a level-discrimination experiment is based on an optimally weighted sum of across-interval excitation-level differences in frequency selective channels, COSS functions will be measured for level discrimination of multitone complexes in which a random jitter is applied to each component. These data will add significantly to our understanding of normal and impaired hearing and will be important for the development and testing of models of the auditory system. Little is known about how the auditory system integrates information across channels, although this ability is critical to our perception of almost all sounds.