Reading Proficiency and Adaptability in Orthographic Processing: An Examination of the Effect of Type of Orthography Read on Brain Activity in Regular and Dyslexic Readers

Irit Bar-Kochva,Zvia Breznitz

doi:10.1371/journal.pone.0086016

Abstract

Regular readers were found to adjust the routine of reading to the demands of processing imposed by different orthographies. Dyslexic readers may lack such adaptability in reading. This hypothesis was tested among readers of Hebrew, as Hebrew has two forms of script differing in phonological transparency. Event-related potentials were recorded from 24 regular and 24 dyslexic readers while they carried out a lexical decision task in these two forms of script. The two forms of script elicited distinct amplitudes and latencies at ∼165 ms after target onset, and these effects were larger in regular than in dyslexic readers. These early effects appeared not to be merely a result of the visual difference between the two forms of script (the presence of diacritics). The next effect of form of script was obtained on amplitudes elicited at latencies associated with orthographic-lexical processing and the categorization of stimuli, and these appeared earlier in regular readers (∼340 ms) than in dyslexic readers (∼400 ms). The behavioral measures showed inferior reading skills of dyslexic readers compared to regular readers in reading of both forms of script. Taken together, the results suggest that although dyslexic readers are not indifferent to the type of orthography read, they fail to adjust the routine of reading to the demands of processing imposed by both a transparent and an opaque orthography.

Highlights

According to the principle of orthographic depth [1,2], orthographies vary from shallow orthographies with transparent grapheme-phoneme relations (e.g. German, Italian), to deep orthographies, in which these relations are opaque (e.g. English)
Presuming the reoccurring pattern of activity at these sites and latencies reflected brain activity associated with the processing of the stimuli presented, these were selected for statistical analysis [38]
The possible effect of the visual load imposed by the Hebrew diacritics on early brain activity was evaluated by analyzing the data from the lexical decision and the non-orthographic tasks in one Repeated Measure ANOVA analysis

Summary

Introduction

According to the principle of orthographic depth [1,2], orthographies vary from shallow orthographies with transparent grapheme-phoneme relations (e.g. German, Italian), to deep orthographies, in which these relations are opaque (e.g. English). The reliance on larger orthographic units has, been more associated with the reading of deep orthographies [1,2,3,4,5]. These differences were suggested to reflect the distinct demands of processing imposed by shallow and deep orthographies: grapheme-phoneme conversion should be efficient in reading when grapheme-phoneme relations are transparent; the same procedure may be insufficient when these relations are opaque. In a PET study by Paulesu and his colleagues [6] localization of brain activity was compared between readers of the deep English orthography and readers of the shallower Italian orthography. Oral reading of unpointed words [52]: A list of 168 unpointed words arranged in order of increasing length (1 to 5 syllables) and decreasing frequency was presented and the participants were asked to accurately read as many words as possible in 1 minute

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Results

Conclusion