Development of electrophysiological auditory response for speech

描述（由申请人提供）：了解正常听力（NH）个体对言语的听觉反应的电生理发展是识别言语感知缺陷儿童异常言语处理延迟的必要步骤。我将用脑电图（EEG）描述语音听觉反应的电生理学发展。我将识别特定年龄的神经振荡模板，这些模板分别区分言语的时间（Aim1）和频谱（Aim2）特性的处理，特别是开始上升时间（ORT）和形成峰结构。电生理变化将基于代表大脑振荡活动动态的三个维度进行评估：(1)神经响应对声学特性的时间排列强度，称为锁相指数（PLI），(2)神经响应的频谱功率（SP），以及(3)相对于言语开始的PLI或SP响应的延迟。这些测量反映了不同的神经机制，这些机制可能是特定于某些语言特性的。基于行为测量，儿童在处理语音时更重视形成峰轨迹而不是包络结构。随着年龄的增长，他们学会利用语音信号提供的包络信息（如ORT）。与行为研究结果相比，脑电图结果显示，儿童低频振荡活动的PLI与声音的频谱编码有关，而成人则利用低频和高频PLI处理声音的频谱信息。此外，PLI延迟与处理ORT有关。低、中频振荡活动的PLI潜伏期在7-9岁左右随ORT开始转移。行为学和电生理学的研究结果共同指出了低频和高频PLI在形成峰加工发展中的可能作用，以及低频和中频振荡活动的PLI潜伏期在ORT加工发展中的作用。基于本研究的年龄模板将随后用于识别言语感知缺陷儿童言语时间和频谱处理的听觉反应发展。

DESCRIPTION (provided by applicant): Understanding the electrophysiological development of the auditory response to speech in normal hearing (NH) individuals is a necessary step in identifying abnormal speech processing delays in children with speech perception deficits. I will characterize the development of the auditory response to speech electrophysiologically using electroencephalography (EEG). I will identify age-specific templates of the neural oscillations that distinguish the processing of temporal (Aim1) and spectral (Aim2) properties of speech, specifically the onset rise time (ORT) and formant structure, respectively. Electrophysiological changes will be assessed based on three dimensions representing the dynamics of brain oscillatory activity: (1) the strength of temporal alignment of the neural response to the acoustical property, referred to as phase-locking index (PLI), (2) the spectral power of the neural response (SP), and (3) the latency of PLI or SP responses with respect to the onset of speech. These measures reflect different neural mechanisms that may be specific to certain speech properties. Based on behavioral measures, children weight formant trajectories more so than envelope structure when processing speech sounds. As they age, they learn to utilize envelope information (e.g. ORT) provided by the speech signal. In comparison to behavioral findings, EEG results revealed that PLI of low- frequency oscillatory activity is associated with coding spectral aspects of sounds in children, while adults utilize low- and high-frequency PLI for processing spectral information of sound. Also, PLI latency is associated with processing the ORT. PLI latency of the low- and mid-frequency oscillatory activity starts to shift with ORT around age 7-9. Together, behavioral and electrophysiological findings point to a possible role of low- and high-frequency PLI in development of formant processing, and a role for PLI latency of low- and mid-frequency oscillatory activity in development of ORT processing. Age- templates based on this study will subsequently be used to identify auditory response development for the temporal and spectral processing of speech in children with speech perception deficits. PUBLIC HEALTH RELEVANCE: The proposed research will help expand our current knowledge of auditory cortex development in normal hearing children. We will identify specific brain activity associated with the development of specific speech properties. In the future, we will use the knowledge obtained from this research to assess auditory development in children with speech and language deficits.