Infant hearing for modulated tones

描述（由申请人提供）：关于婴儿听力灵敏度和声音辨别能力的表征，存在有待解决的理论和实践问题。了解这些听力能力是在检测到婴儿听力损失时确定适当的听力障碍策略的关键。这个项目解决了利用对振幅和频率调制音调的电生理反应来表征婴儿听力的挑战。结合电生理学方法，将采用特定年龄的心理物理测量来估计幼儿的阈值和辨别能力。如果我们成功的话，就有可能将听觉灵敏度和中枢听觉神经系统成熟的电生理学相关性与感知能力联系起来。本研究的长期目标是了解婴儿如何以及何时发展检测，辨别和感知语音的能力，并通过电生理学和心理物理学方法评估这种发展。言语理解的构建块被定义为1）对“言语频率”（500-4000 Hz）的听觉灵敏度，2）如在言语频率中的调制音调的神经锁相中所反映的时间处理; 3）对幅度调制和频率调制的灵敏度和辨别力; 4）对由两个或更多个调制分量组成的复杂声音的辨别力。本研究旨在利用听觉电生理学和心理物理学来描述对振幅（AM）和频率（FM）调制音调以及由多个载波和调制频率组成的复杂声音的反应的时间过程和动态，以探索这些语音理解的构建块。研究结果将有助于人类听觉系统如何发展对复杂信号的反应和辨别能力的新知识。这项研究还将产生评估婴儿阈值敏感度和声音辨别力的方法，这些方法可应用于那些有听力损失或其他听觉功能障碍风险的人。

DESCRIPTION (provided by applicant): There are theoretical and practical problems to be solved concerning the characterization of hearing sensitivity and sound discrimination abilities in infants. Knowledge of these hearing capabilities is key to determining appropriate habilitation strategies when infants are detected with hearing loss. This project addresses the challenge of characterizing hearing in infants using electrophysiologic responses to amplitude and frequency modulated tones. In conjunction with electrophysiologic methods, age-specific psychophysical measures will be employed to estimate threshold and discrimination abilities in young infants. If we are successful, it may be possible to relate electrophysiologic correlates of hearing sensitivity and central auditory nervous system maturation to perceptual abilities. The long-term goals of this research are to understand how and when infants develop the capacity to detect, discriminate and perceive speech and the evaluation of this development through electrophysiologic and psychophysical methods. The building blocks of speech understanding are defined as 1) hearing sensitivity for "speech frequencies" (500-4000 Hz), 2) temporal processing as reflected in neural phase-locking for modulated tones in the speech frequencies; 3) sensitivity to and discrimination of amplitude modulation and frequency modulation; 4) discrimination of complex sounds composed of two or more modulated components. The research plan is developed to explore these building blocks of speech understanding using auditory electrophysiology and psychophysics to describe the time course and dynamics of responsiveness to amplitude (AM) and frequency (FM) modulated tones and complex sounds composed of multiple carder and modulation frequencies. The research outcomes will contribute new knowledge about how the human auditory system develops the capacity to respond to and discriminate complex signals. This research will also result in methods for assessing threshold sensitivity and sound discrimination in infants that can be applied to those at risk for hearing loss or other auditory dysfunction.