Reading for deaf and hearing readers: qualitatively and/or quantitatively similar or different? A nature versus nurture issue.

The authors discuss whether the covert reading process differs qualitatively and/or quantitatively for hearing and deaf peers and whether formal reading instruction should be different for deaf and hearing students. The authors argue that hearing status (deaf, hearing) is less important in learning to read than environmental factors, including: (a) the richness of the early linguistic environment leading to an age-appropriate L1 prior to formal reading instruction and (b) clear, complete visual access to the instructional language (e.g., English, Spanish, American Sign Language) used to deliver curriculum via conventional or English Language Learner methods. In U.S. schools attended by 89% of deaf students, English is "regularly" used as the language of instruction (Gallaudet Research Institute, 2013, p. 11). Of the available communication systems for conveying English conversationally (oral-aural methods, Manually Coded English sign systems, Cued Speech), only Cued Speech is structurally capable of affording clear, complete visual access to English.

Cortical plasticity for visuospatial processing and object recognition in deaf and hearing signers.

Experience-dependent plasticity in deaf participants has been shown in a variety of studies focused on either the dorsal or ventral aspects of the visual system, but both systems have never been investigated in concert. Using functional magnetic resonance imaging (fMRI), we investigated functional plasticity for spatial processing (a dorsal visual pathway function) and for object processing (a ventral visual pathway function) concurrently, in the context of differing sensory (auditory deprivation) and language (use of a signed language) experience. During scanning, deaf native users of American Sign Language (ASL), hearing native ASL users, and hearing participants without ASL experience attended to either the spatial arrangement of frames containing objects or the identity of the objects themselves. These two tasks revealed the expected dorsal/ventral dichotomy for spatial versus object processing in all groups. In addition, the object identity matching task contained both face and house stimuli, allowing us to examine category-selectivity in the ventral pathway in all three participant groups. When contrasting the groups we found that deaf signers differed from the two hearing groups in dorsal pathway parietal regions involved in spatial cognition, suggesting sensory experience-driven plasticity. Group differences in the object processing system indicated that responses in the face-selective right lateral fusiform gyrus and anterior superior temporal cortex were sensitive to a combination of altered sensory and language experience, whereas responses in the amygdala were more closely tied to sensory experience. By selectively engaging the dorsal and ventral visual pathways within participants in groups with different sensory and language experiences, we have demonstrated that these experiences affect the function of both of these systems, and that certain changes are more closely tied to sensory experience, while others are driven by the combination of sensory and language experience.

Phonological awareness and short-term memory in hearing and deaf individuals of different communication backgrounds.

Previous work in deaf populations on phonological coding and working memory, two skills thought to play an important role in the acquisition of written language skills, have focused primarily on signers or did not clearly identify the subjects' native language and communication mode. In the present study, we examined the effect of sensory experience, early language experience, and communication mode on the phonological awareness skills and serial recall of linguistic items in deaf and hearing individuals of different communicative and linguistic backgrounds: hearing nonsigning controls, hearing users of ASL, deaf users of ASL, deaf oral users of English, and deaf users of cued speech. Since many current measures of phonological awareness skills are inappropriate for deaf populations on account of the verbal demands in the stimuli or response, we devised a nonverbal phonological measure that addresses this limitation. The Phoneme Detection Test revealed that deaf cuers and oral users, but not deaf signers, performed as well as their hearing peers when detecting phonemes not transparent in the orthography. The second focus of the study examined short-term memory skills and found that in response to the traditional digit span as well as an experimental visual version, digit-span performance was similar across the three deaf groups, yet deaf subjects' retrieval was lower than that of hearing subjects. Our results support the claim (Bavelier et al., 2006) that lexical items processed in the visual-spatial modality are not as well retained as information processed in the auditory channel. Together these findings show that the relationship between working memory, phonological coding, and reading may not be as tightly interwoven in deaf students as would have been predicted from work conducted in hearing students.

Rhyme generation in deaf students: the effect of exposure to cued speech.

This study compares the rhyme-generation ability of deaf participants with severe to profound hearing losses from cued speech (CS) and non-cued speech (NCS) backgrounds with a hearing comparison group for consistent orthography-to-phonology (O-P) rhyming elements, or rimes (e.g., -ail in sail is always pronounced the same), and inconsistent orthography-to-phonology (I-O-P) rhyming elements where the orthographic rime (e.g., -ear) has different pronunciations in words such as bear, and rear. Rhyming accuracy was better for O-P target words than for I-O-P target words. The performance of the deaf participants from CS backgrounds, although falling between that of the hearing and the NCS groups, did not differ significantly from that of the hearing group. By contrast, the performance of the NCS group was lower than that of the hearing group. Hearing and CS participants produced more orthographically different responses (e.g., blue-few), whereas participants from the NCS group produced more responses that are orthographically similar (e.g., blue-true), indicating that the hearing and CS groups rely more on phonology and the NCS group more on spelling to generate rhymes. The results support the use of cued speech for developing phonological abilities of deaf students to promote their reading abilities.