ENVELOPE & CO-MODULATION CUES IN NORMAL & IMPAIRED EARS

我们的长期目标是， 听觉系统，将允许定量建模的 正常人和受损人的音调、噪音和言语感受 听证会 这些模型不仅将提高我们对 正常的听觉过程，但也将大大有助于 为听力障碍提供更好的诊断工具， 更好地康复听力受损的听众。 拟议 项目旨在获得一套连贯的参数数据， 连续和同时包络比较。 连续 包络比较是在判别实验中检验的 包络（调幅）频率的差异。 同时包络比较测试实验 共调线索对重复频率的影响 歧视（即，共调制提示包络频率 歧视，CCEFD）和掩蔽（即，共调制 掩蔽释放，CMR）。 基于强迫选择实验， 正常的听众，受损的听众， 通过掩蔽正常耳朵来模拟损伤，我们的目标是 建立一个坚实的心理声学基础， 受损的听众对包络波动的处理， 不同听觉通道的包络相关性。 我们的具体 目的是（1）确定光谱和时间线索在 解释在不同的实验中得到的不同结果， 滤波后脉冲序列的速率鉴别实验 双音同频分辨力实验 配合物 将比较包络频率鉴别 对于双音复合体，带通滤波脉冲序列，以及低- 通过乘以正弦曲线的滤波脉冲串。 低通 滤波的、倍增的脉冲串具有类似于频带的包络， 通过滤波脉冲序列，但-像双音复合-产生 对于给定的包络变化只有很小的光谱变化 频率. (2)测试听众可能能够做出的假设 为了比较不同频率下的同时调制波形， 频率，并利用这些信息来提高对 在一个频率处， 在另一频率处存在共调制线索。 几 CCEFD的相关线索，不相关线索， 并且不执行提示。 (3)为了映射参数， 控制CCEFD中相关线索的效率。 实验 旨在系统地探索频率的影响 信号和提示之间的分离、提示位置和提示水平。 （四） 为了检验假设， CCEFD和CMR来自相同的听觉过程-直接 比较不同频率下的包络。 的影响 将比较信号频率和包络频率 系统地进行了CCEFD实验和 CMR。 这些实验将有助于确定 以及受损听众可能出现的缺陷的根本原因 在信封处理和提供重要的数据， 正常人和受损人CCEFD和CMR的定量建模 听证会

Our long-term objective is to reach an understanding of the auditory system that will allow quantitative modeling of the preception of tone, noise, and speech in both normal and impaired hearing. Such models not only will improve our understanding of normal auditory processes, but also will aid significantly in providing better diagnostic tools for hearing impairment and better rehabilitation of hearing-impaired listeners. The proposed project aims to obtain a coherent set of parametric data on successive and simultaneous envelope comparisons. Successive envelope comparisons are tested in experiments on discrimination of a difference in envelope (amplitude-modulation) frequency. Simultaneous envelope comparisons are tested in experiments on the effect of a co-modulated cue on envelope-frequency discrimination (i.e., Co-modulation Cued Envelope-Frequency Discrimination, CCEFD) and on masking (i.e., Co-modulation Masking Release, CMR). Based on forced-choice experiments in normal listeners, impaired listeners, and listeners with impairments simulated by masking a normal ear, we aim to establish a firm psychoacoustic basis for a model of normal and impaired listeners' processing of envelope fluctuations and envelope correlations in different auditory channels. Our specific aims are (1) To determine the roles spectral and temporal cues in explaining the qualitatively different results obtained in experiments on rate discrimination of filtered pulse trains and in experiments on envelope-frequency discrimination of two-tone complexes. Envelope-frequency discrimination will be compared for two-tone complexes, band-pass filtered pulse trains, and low- pass filtered pulse trains multiplied by a sinusoid. The low-pass filtered, multiplied pulse trains have envelopes similar to band- pass filtered pulse trains, but--like two-tone complexes--produce only small spectral changes for a given change in envelope frequency. (2) To test the hypotheses that listeners may be able to compare simultaneous modulation waveforms at different frequencies and use the information to improve discrimination of an envelope-frequency difference at one frequency in the presence of a co-modulated cue at another frequency. Several experiments on CCEFD with correlated cues, uncorrelated cues, and no cue will be performed. (3) To map the parameters that govern the efficiency of a correlated cue in CCEFD. Experiments are designed to explore systematically the effects of frequency separation between signal and cue, cue position, and cue level. (4) To test the hypothesis that the co-modulation advantage in CCEFD and CMR result from the same auditory process--direct comparison of envelopes at different frequencies. The effects of signal frequency and envelope frequency will be compared systematically in experiments on CCEFD and experiments on CMR. These experiments will aid in determining both the extent and the underlying causes for impaired listeners' probable deficits in envelope processing and provide important data for quantitative modeling of CCEFD and CMR in normal and impaired hearing.