INTENSITY DLS AND MASKING IN NORMAL AND IMPAIRED HEARING

我们的长期目标是， 听觉系统，将允许定量建模的 在正常人和正常人中对音调、噪音和语言的感知， 听力受损 这样的模型不仅会改善我们的 了解正常的听觉过程，但也将 为听力提供更好的诊断工具 听力障碍和更好的康复 听众 拟议项目旨在获得一些急需的 数据，并继续测试的一般概念，激励 模式可以为定量建模提供框架， 正常和受损的听力。 根据21，2AFC实验， 正常的听众，受损的听众， 通过掩蔽正常耳朵来模拟损伤， 项目将建立一个坚实的心理声学基础，完善我们的 强度鉴别和测试的激发模式模型 与这个模型和其他模型相关的几个假设。 我们的具体 目的是（1）检验两个假设，说明灵敏度，d '， 取决于两个声音之间的电平差 通过心理测量功能的测量进行区分， 强度辨别，主要是在具有大DL的条件下。 (2)为了检验韦伯定律在一个假设范围内不成立的假设， 单一听觉通道 作为水平函数的强度DL将 被测量的声音，其激励是有限的随机- 电平掩蔽器包括少量听觉通道。 (3)为了检验噪声中音调信号的检测 和强度区分取决于类似的决策规则， 使用来自一个非最佳的信息的未加权（非最佳）总和， 渠道的优化选择。 检测和 1 kHz音调和16音调复合体的强度鉴别 将在固定的条件下进行，在这些条件下， 从试验到试验随机地呈现两种类型的信号。 (4)为了开始扩展该模型， 声音随时间而变化。 听觉的方式 系统可以使用随时间变化的激励电平信息， 通过测量强度的灵敏度d '进行评估 辨别力是刺激持续时间的函数。 (5)的 假设是，兴奋水平的信息减少超过 由于听觉系统中的适应过程， 在几个实验中测试。 多色调强度DL 脉冲串将被测量为脉冲串数量的函数， 脉冲串间隔。 在其他实验中， 将在存在前一个的情况下测量简短的音调， 适应不同持续时间的音调。 (6)进一步调查 时变声音的处理和决策的灵活性 过程中，从掩蔽释放引起掩蔽--包络 将在几个实验中研究波动。 这些 数据将大大增加我们对正常和 受损的听觉处理，将是重要的， 开发和测试听觉系统模型。

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 not only will improve our understanding of normal auditory processes, but also will significantly aid in providing better diagnostic tools for hearing impairment and better rehabilitation of hearing-impaired listeners. The proposed project aims to obtain some sorely needed data and to continue testing the general concept that excitation patterns may provide a framework for quantitative modeling of normal and impaired hearing. Based on 21, 2AFC experiments in normal listeners, impaired listeners, and listeners with impairments simulated by masking a normal ear, the proposed project will establish a firm psychoacoustic basis for refining our excitation-pattern model of intensity discrimination and testing several hypotheses related to this and other models. Our specific aims are (1) To test two hypotheses stating how sensitivity, d', depends on the level difference between two sounds being discriminated by measurements of psychometric functions for intensity discrimination, primarily in conditions with large DLs. (2) To test the hypothesis that Weber's Law does not hold within a single auditory channel. Intensity DLs as a function of level will be measured for sounds whose excitation is limited by random- level maskers to comprise a small number of auditory channels. (3) To test the hypothesis that detection of tonal signals in noise and intensity discrimination depends on similar decision rules and employ an unweighted (non-optimal) sum of information from an optimum selection of channels. Measurements of detection and intensity discrimination of a 1-kHz tone and a 16-tone complex will be made in fixed conditions and in conditions in which these two types of signals are presented at random from trail to trial. (4) To begin extending the model to account for discrimination of sounds that vary over time. The manner in which the auditory system can use excitation-level information over time will be assessed through measurements of sensitivity, d', for intensity discrimination as a function of stimulus duration. (5) The hypothesis is that excitation-level information decreases over time due to adaptation processes in the auditory system will be tested in several experiments. Intensity DLs for multiple tone bursts will be measured as function of number of the bursts and the inter-burst interval. In other experiments, intensity DLs for brief tones will be measured in the presence of a preceding, adapting tone of various durations. (6) To further investigate the processing of time-varying sounds and the flexibility of decision processes, the release from masking caused by masker--envelope fluctuations will be investigated in several experiments. These data will significantly add to our knowledge of normal and impaired auditory processing and will be important for the development and testing of models of the auditory system.