Deaf readers benefit from lexical feedback during orthographic processing

Eva Gutierrez-Sigut,Manuel Perea,Marta Vergara-Martínez

doi:10.1038/s41598-019-48702-3

Eva Gutierrez-Sigut, Manuel Perea + Show 1 more

Open Access

https://doi.org/10.1038/s41598-019-48702-3

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Abstract

It has been proposed that poor reading abilities in deaf readers might be related to weak connections between the orthographic and lexical-semantic levels of processing. Here we used event related potentials (ERPs), known for their excellent time resolution, to examine whether lexical feedback modulates early orthographic processing. Twenty congenitally deaf readers made lexical decisions to target words and pseudowords. Each of those target stimuli could be preceded by a briefly presented matched-case or mismatched-case identity prime (e.g., ALTAR-ALTAR vs. altar- ALTAR). Results showed an early effect of case overlap at the N/P150 for all targets. Critically, this effect disappeared for words but not for pseudowords, at the N250—an ERP component sensitive to orthographic processing. This dissociation in the effect of case for word and pseudowords targets provides strong evidence of early automatic lexical-semantic feedback modulating orthographic processing in deaf readers. Interestingly, despite the dissociation found in the ERP data, behavioural responses to words still benefited from the physical overlap between prime and target, particularly in less skilled readers and those with less experience with words. Overall, our results support the idea that skilled deaf readers have a stronger connection between the orthographic and the lexical-semantic levels of processing.

Highlights

Deaf individuals often find reading an extremely difficult task
Regarding the event related potentials (ERPs), we focused on the N/P150 and the N250 ERP components because they allow for the dissociation of physical-feature overlap effects from abstract-orthographic overlap effects—for consistency with previous research we tracked down the effects in a later time window (N400)
We found a main effect of case in an early component associated to perceptual processes (N/P150)

Summary

Introduction

Deaf individuals often find reading an extremely difficult task. Most deaf adults only achieve a reading level equivalent to that of a 10-year-old (see e.g. English: ref.[1]; Spanish: ref.2), and this may negatively impact their academic achievement and social and emotional well-being[3]. A demonstration of fast access to abstract, orthographic representations during word recognition is that a number of behavioural lexical decision experiments have shown similar response times to a target word like ALTAR when preceded by a prime that is both nominally and physically identical (e.g., ALTAR) and when preceded by a prime that is nominally, but not physically identical (e.g., altar). This effect of matched- vs- mismatched case has been consistently found in adult skilled readers and in developing readers[12] and in readers of non-alphabetic scripts (e.g., Hiragana and Katakana[13]). The left fusiform gyrus and both right and left precentral gyrus showed repetition suppression for masked identity priming independently of case overlap between prime and target (see ref.[15] for a review)

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