Doctoral Dissertation Research: Neurobiological Correlates of Phonological Awareness and Reading Outcomes

阅读技能在年轻学习者及其参与21世纪经济的能力中发挥着核心作用，这凸显了高识字率对创新型劳动力的重要性。阅读理解困难以及随之而来的缺乏获取书面思想和信息的机会是许多阅读能力差的儿童（例如，城市和农村贫困儿童、有阅读障碍的儿童和失聪儿童）面临的问题。在这些人群中的研究发现都促进了我们对阅读发展多样性的理解，并支持了针对不同类型年轻读者的最佳教学策略的发展。聋儿的阅读能力各不相同，但平均而言，尽管听力技术（如助听器和人工耳蜗）不断进步，几十年来各种各样的方法提供了可见的口头语言（如演讲阅读、提示演讲、手语准确英语），聋儿的阅读能力仍然远远落后于听力正常的同龄人。通过对成功的聋人阅读者的研究，研究人员一再发现，手语熟练程度与阅读结果之间存在很强的相关性。不幸的是，目前还不清楚手语能力的哪些方面对聋儿的阅读效果有影响。语音意识（phonological awareness， PA）是听力儿童阅读能力的一个重要预测指标，即识别和操纵单词语音结构的能力。最近的行为研究发现，手语的语音意识与聋儿的阅读有关，但手语和口语的语音意识是否是一种共同认知机制的产物尚不清楚。本项目将探讨美国手语和英语的PA的大脑基础，并提出聋儿语音意识和阅读发展的两个假设。语音依赖假说认为，语音对阅读至关重要，聋儿的语音加工是延迟的，而不是异常的。抽象的语音表征是由可获得的听觉信号和视觉发音线索（即嘴部运动）组合而成的，这些线索可以随着时间的推移而加强。语音表征虽然延迟，但却是聋儿语音意识和阅读的基础。根据情态独立假说，抽象的语音表征与言语无关，而是情态的。当孩子们早期自然地接触语言时，无论语态如何，他们都会发展出强大的语音表征，从而产生分段和操纵语音信息的PA技能，这些技能可以应用于学习阅读。为了验证这些假设，我们将招募使用美国手语的聋儿和听单语英语的聋儿，他们被录取在K - 6年级。所有儿童将接受标准化阅读理解和非语言智商评估。在进行功能性近红外光谱（fNIRS）神经成像的同时，我们将使用非正字法、非语言图片匹配范式评估美国手语和英语PA的脑基础。分析将探讨在两种模式下为PA激活的大脑区域与阅读理解之间的关系。这项研究的发现有望提高我们对语言神经生物学的认识，并有助于聋儿识字教学的教育方法。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。

The central role that reading skill plays in the young learner and their ability to engage in the 21st century economy highlights the importance of high literacy rates for an innovative workforce. Reading comprehension difficulties and concomitant lack of access to printed ideas and information is a problem for a wide range of populations of children with poor reading skills (e.g. poor urban and rural children, children with dyslexia, and deaf children.) Research discoveries in each of these populations have advanced our understanding of the diversity of reading development and supported the development of optimal instructional strategies for various types of young readers. Deaf children's reading abilities vary, but on average have remained far behind those of their hearing peers despite advancements in hearing technologies (e.g., hearing aids and cochlear implants) and decades of various approaches to providing visible access to spoken language (e.g., speechreading, Cued Speech, Signed Exact English). By examining successful deaf readers, researchers have repeatedly found examined strong correlations between sign language proficiency and reading outcomes. Unfortunately, it has remained unclear exactly what aspects of sign language proficiency contribute to reading outcomes in deaf children. One important predictor of reading abilities in hearing children is phonological awareness (PA), the ability to identify and manipulate the phonological structure of words, and recent behavioral research has found that PA for signed languages is related to deaf children's reading, but whether signed and spoken language PA are the product of a common cognitive mechanism remains unclear.This project will investigate the brain basis of PA for American Sign Language (ASL) and English and address two hypotheses of phonological awareness and reading development in deaf children. The spoken language phonology dependent hypothesis holds that spoken language phonology is essential for reading, and that phonological processing in deaf children is delayed rather than abnormal. Abstract phonological representations are assembled from the accessible auditory signal and visual articulatory cues (i.e., mouth movements) that can be strengthened over time. Though delayed, the phonological representations are the basis for phonological awareness and reading in deaf children. According to the modality independent hypothesis, abstract phonological representations are not tied to speech, but are amodal. When children have early, natural exposure to language, regardless of modality, they develop strong phonological representations which give rise to PA skills for segmenting and manipulating phonological information that can be applied to learning to read. To test these hypotheses, we will recruit deaf children who use ASL and hearing monolingual English speakers enrolled in grades K - 6. All children will be administered standardized reading comprehension and nonverbal IQ assessments. While undergoing functional near infrared spectroscopy (fNIRS) neuroimaging, we will assess the brain bases of ASL and English PA using a non-orthographic, non-linguistic picture-matching paradigm. Analyses will investigate the relationships between brain regions activated for PA in both modalities and reading comprehension. Findings from this study promise to advance our knowledge of the neurobiology of language and to contribute to educational approaches in literacy instruction with deaf children.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.