Infant hearing for modulated tones

描述(由申请人提供)：关于婴儿听力敏感度和声音辨别能力的特征，有理论和实际问题需要解决。当婴儿被检测到听力损失时，这些听力能力的知识是确定适当的康复策略的关键。这个项目解决了利用对幅度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，将使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。如果我们成功了，就有可能将听觉敏感度和中枢听觉神经系统成熟的电生理学关联与感知能力联系起来。这项研究的长期目标是了解婴儿如何以及何时发展检测、辨别和感知语言的能力，并通过电生理和心理物理方法评估这种发展。语音理解的基础被定义为：1)对“语音频率”(500-4000赫兹)的听觉敏感性；2)对语音频率中调制音调的神经锁相所反映的时间处理；3)对调幅和调频的敏感性和辨别；4)对由两个或更多调制成分组成的复杂声音的辨别。该研究计划旨在利用听觉电生理学和心理物理学来探索语音理解的这些构件，以描述对幅度(AM)和频率(FM)调制的音调和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力学。研究成果将为人类听觉系统如何发展对复杂信号的反应和辨别能力提供新的知识。这项研究还将得出评估婴儿阈值敏感度和声音辨别能力的方法，这些方法可以应用于听力损失或其他听力障碍的风险人群。

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.