Clifton Langdon - US grants

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.