The neural underpinnings of reading skill in deaf adults

Abstract

We investigated word-level reading circuits in skilled deaf readers (N=14; mean reading age=19.5years) and less skilled deaf readers (N=14; mean reading age=12years) who were all highly proficient users of American Sign Language. During fMRI scanning, participants performed a semantic decision (concrete concept?), a phonological decision (two syllables?), and a false-font control task (string underlined?). No significant group differences were observed with the full participant set. However, an analysis with the 10 most and 10 least skilled readers revealed that for the semantic task (vs. control task), proficient deaf readers exhibited greater activation in left inferior frontal and middle temporal gyri than less proficient readers. No group differences were observed for the phonological task. Whole-brain correlation analyses (all participants) revealed that for the semantic task, reading ability correlated positively with neural activity in the right inferior frontal gyrus and in a region associated with the orthography-semantics interface, located anterior to the visual word form area. Reading ability did not correlate with neural activity during the phonological task. Accuracy on the semantic task correlated positively with neural activity in left anterior temporal lobe (a region linked to conceptual processing), while accuracy on the phonological task correlated positively with neural activity in left posterior inferior frontal gyrus (a region linked to syllabification processes during speech production). Finally, reading comprehension scores correlated positively with vocabulary and print exposure measures, but not with phonological awareness scores.

Language and Literacy: Issues and Considerations

“…Alternately, other studies have not shown clear use of phonological processing in deaf readers [78][79][80][81]. As a result, some researchers believe phonology might be bypassed by focusing on morphemes in the orthography of text.…”

Early use of phonological codes in deaf readers: An ERP study

“…In the Bélanger et al (2012) experiment, the size of masked phonological priming was not predictive of the reading level in deaf readers. Similarly, in a recent fMRI study comparing skilled and less skilled deaf readers, Emmorey, McCullough, and Weisberg (2016) found that reading ability was not correlated with off-line measures of phonological awareness nor with neural activity during a phonological (syllable counting) task. In the current study, we make use of the variability of reading levels existing amongst congenitally deaf participants to analyze the relationships between their score in standardized reading tests and performance during the task as well as the size of the ERP effects.…”

Young skilled deaf readers have an enhanced perceptual span in reading

“…Because phonological processing plays a central role in read acquisition for hearing readers, much research on deaf readers has focused on whether or not they activate phonological representations when reading and whether such abilities determine reading skills (Daigle & Armand, 2008;Hanson & Fowler, 1987;Perfetti & Sandak, 2000). While these questions still dominate the field (Emmorey, McCullough, & Weisberg, 2016;Hirshorn, Dye, Hauser, Supalla, & Bavelier, 2015), no consensus exists about the role of phonological processes in deaf readers, likely due to the heterogeneity of the population and to methodological differences across studies: some find phonological activation in deaf readers (Daigle & Armand, 2008;Transler, Gombert, & Leybaert, 2001) while others do not (Bélanger, Baum, & Mayberry, 2012;Bélanger, Mayberry, & Rayner, 2013;Cripps, McBride, & Forster, 2005;Waters & Doehring, 1990).…”