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

该研究项目旨在更好地了解植入人工耳蜗（CIs）的儿童如何实时理解口语。CIs改变了先天性聋哑儿童的生活，使他们能够通过电刺激听神经来听到声音。然而，CI并不像普通耳朵那样向大脑传递相同的信号。事实上，将声音输入转换为电听力会降低语音信号，使其更难理解。这个项目的目的是确定退化的CI信号如何影响CI儿童的口语处理，以便更好地理解语音输入的质量如何影响语音感知和口语的发展。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、家庭和其他经常与失聪或听力障碍儿童打交道的各方分享。这一交流将促进转化应用，如制定更准确的评估方案、有针对性的治疗方法和与儿童人工耳蜗植入相关的政策建议。通过帮助解释儿童如何通过他们感知的语音输入习得语言，研究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。本研究项目利用眼动追踪和脑电图（EEG）来识别自闭症儿童口语加工延迟的认知机制。第一个目标是通过区分两种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，特别是依赖于频谱线索（例如，sip与ship）的音素区分，这些线索没有被CI很好地传递；2) CI患儿对所有单词都采取“观望”策略，不管CI对某个特定单词的声学特征传达得有多好。第二个目标是通过区分两种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)CIs儿童表现出口语单词的级联处理，语音感知中的歧义将导致更分散的相似发音单词及其语义关联网络的激活不那么强大；或2)ci儿童对口语单词的处理表现出更多的序列性，其中语音级别的歧义延迟了更高级别语言网络的激活。这些发现将为理解语音输入的质量如何影响语言理解的加工机制提供重要的一步，推动口语加工理论的发展，并为ci儿童的口语干预提供信息。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.