Doctoral Dissertation Research: Determining the mechanisms of spoken language processing delay for children with cochlear implants

这项研究项目旨在更好地了解植入人工耳蜗(CI)的儿童如何实时理解口语。CI改变了先天失聪儿童的生活，使他们能够通过电刺激听神经来听力。然而，CI并不像典型的耳朵那样向大脑传递相同的信号。事实上，将声学输入转换为电听会降低语音信号的质量，使其更难理解。本项目的目的是确定CI信号的退化如何影响CI儿童的口语处理，以便更好地了解语音输入的质量如何影响言语感知和口语的发展。这项研究的结果将与该领域的研究人员以及学校、临床医生、家庭和其他经常与聋哑人或重听儿童合作的各方分享。这种交流将促进翻译应用，如开发更准确的评估方案，有针对性的治疗方法，以及与儿科人工耳蜗术相关的政策建议。通过帮助解释儿童如何通过他们感知的语音输入获得语言，结果将帮助父母更好地理解如何与孩子互动，以支持口语学习。本研究项目使用眼球追踪和脑电(EEG)来确定认知机制，其潜在的观察到的认知延迟的口语处理顺位儿童。第一个目标是通过区分两个假设来确定口语单词识别中观察到的延迟的来源：1)延迟是单词之间竞争加剧的结果，特别是对于依赖于CI不能很好地传输的光谱提示(例如，sip与ship)的音素区分；或者2)CI儿童对所有单词都采用“观望”策略，而不管CI如何很好地传达任何特定单词的声学特征。第二个目标是通过区分两个假设来确定口语单词识别的延迟如何阻碍语义信息的获取：1)顺位儿童表现出对口语单词的级联加工，语音感知中的意义模糊会导致更分散的发音相似的单词及其语义联系的网络的激活不那么稳健；或者2)顺位儿童表现出对口语单词的更连续的加工，其中语音水平的歧义延迟了高级语言网络的激活。这些发现将在理解语音输入质量如何影响语言理解的处理机制方面向前迈出重要的一步，推动口语处理理论的发展，并为患有CI的儿童提供口语干预。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This research project seeks to better understand how children with cochlear implants (CIs) understand spoken language in real time. CIs have transformed the lives of children who are born Deaf, enabling them to hear via electrical stimulation of the auditory nerve. However, the CI does not deliver the same signal to the brain that a typical ear does. In fact, the transformation of the acoustic input into electric hearing degrades the speech signal, making it harder to understand. The objective of this project is to determine how the degraded CI signal impacts spoken language processing by children with CIs in order to better understand how the quality of speech input impacts the development of speech perception and spoken language. The findings from this research will be shared with researchers in the field as well as schools, clinicians, families, and other parties who regularly work with children who are Deaf or Hard-of-Hearing. This communication will promote translational applications such as the development of more accurate assessment protocols, targeted treatment approaches, and policy recommendations related to pediatric cochlear implantation. By helping explain how children acquire language with the speech input they perceive, the results will help parents better understand how to interact with their children to support spoken language learning. This research project uses eye-tracking and electroencephalography (EEG) to identify the cognitive mechanisms underlying observed delays in spoken language processing by children with CIs. The first objective is to determine the source of observed delays in spoken word recognition by distinguishing between two hypotheses: 1) Delays are the result of increased competition between words, specifically for phoneme distinctions relying on spectral cues (e.g., sip vs. ship) that are not transmitted well by the CI; or 2) Children with CIs adopt a "wait-and-see" strategy for all words, regardless of how well the CI conveys the acoustic features of any particular word. The second objective is to determine how delays in spoken word recognition hinder access of semantic information by distinguishing between two hypotheses: 1) Children with CIs exhibit cascading processing of spoken words, meaning ambiguities in speech perception would result in less robust activation of a more distributed network of similar-sounding words and their semantic associates; or 2) Children with CIs demonstrate more serial processing of spoken words, in which ambiguity at the speech sound level delays activation of higher-level language networks. These findings will provide an important step forward in understanding how the quality of speech input impacts processing mechanisms underlying language comprehension, advancing theories of spoken language processing along with informing spoken language intervention for children with CIs.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.