Lexical Knowledge and Phonological Awareness in Children with Cochlear Implants

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PROJECT SUMMARY A majority of children who receive cochlear implants at an early age read below an eighth-grade level in high school (Geers & Hayes, 2011). One early cause of this reading problem is likely a deficit in phonological awareness, the ability to analyze the sounds of language. The cause of poor phonological awareness in children with cochlear implants may be related to vocabulary knowledge rather than speech perception. The Lexical Restructuring Model proposes that phonological awareness develops as children's lexicons grow and children restructure word representations. The objective of the proposed study is to test the Lexical Restructuring Model as a potential account of poor phonological awareness in children with cochlear implants. The central hypotheses are that (a) children with cochlear implants know fewer dense words than children with normal hearing matched for age and vocabulary size, (b) children with cochlear implants develop weaker phonological connections between similar words than children matched for age and vocabulary size, and (c) children with cochlear implants will demonstrate less proficiency completing phonological awareness tasks for words with high neighborhood density than children with normal hearing. The rationale for the proposed study is to provide preliminary evidence characterizing the lexical basis of phonological awareness in children with cochlear implants such that hypotheses about intervention can be tested in a large-scale project. The specific aims include: (a) determine whether children with cochlear implants know fewer dense words than children with normal hearing matched for age and matched for vocabulary size, (b) determine whether children with cochlear implants demonstrate the same awareness of phonological connections between words as children with normal hearing matched for age and matched for vocabulary size and (c) determine whether children with cochlear implants perform more poorly than children with normal hearing matched for age and matched for vocabulary size on phonological awareness tasks for dense versus sparse vocabulary words. The proposed study will enroll 90 children between 5;0 and 6;11: 30 with cochlear implants, 30 with normal hearing matched for age, and 30 matched for vocabulary size. Children will complete three experimental tasks to determine: (1) if children with cochlear implants know relatively more words with sparse neighborhood density than high neighborhood density as compared to children with normal hearing, (2) if phonological priming facilitates reaction time for judgments in children with cochlear implants as for children with normal hearing, and (3) if children with cochlear implants perform more poorly on phonological awareness tasks than children with normal hearing, particularly in tasks involving words with sparse neighborhood density. The proposed research is significant because it tests a hypothesis about a cause of poor phonological awareness beyond speech perception in children with cochlear implants, thereby advancing the field of language development in children with hearing loss, where there is a paucity of research about underlying causes of poor literacy outcomes.