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.