The unique contribution of letter-sound integration to English-speaking children’s reading performance

The unique contribution of letter-sound integration to English-speaking children’s reading performance

First Author: Silvia Siu-Yin Clement-Lam -- Northwestern University
Additional authors/chairs: 
Brittany Manning; Sean McWeeny; Elizabeth S. Norton
Keywords: letter-sound integration, Dyslexia, Automaticity, Reading Ability, Multi-componential view of dyslexia
Abstract / Summary: 

PURPOSE:
A deficit in letter-sound integration (LSI) has been suggested as a contributing factor in developmental dyslexia, but has been tested primarily in transparent orthographies such as Dutch. Methods for assessing LSI also vary widely. This study examined letter-sound integration whether automaticity of LSI could be manipulated by adjusting the stimulus onset asynchrony (SOA) of letter-sound stimulus pairs; we further assessed how reading ability related to performance on the letter-sound task in English-speaking children.

METHOD:
Children (n=67, ages 8-12) of varying reading ability completed a battery of phonological awareness (PA), RAN, and reading measures. Factor scores were created for each construct. The experimental letter-sound matching task had different levels of stimulus onset asynchrony (SOA). Visual letters and auditory speech sounds were presented simultaneously (0ms SOA) or with SOA of 200 or 400ms (both letter before sound and vice-versa). Children indicated whether each pair was matched/congruent (“n”/n) or unmatched (“p”/r). Reaction time (RT) and efficiency (RT and accuracy combination, using binning procedure) were calculated.

RESULTS:
Children’s RT on the letter-sound matching task was significantly faster in low-demand (high SOA) conditions (F=4.17, p=.004). LSI efficiency in the high-demand 0ms condition was related to reading proficiency, even after accounting for phonological awareness and RAN (∆R^2 = 0.04), but low-demand 400ms SOA performance was not significantly related to reading.

CONCLUSIONS:
This study shows that LSI is related to children's reading performance, and that the measure used to assess LSI is highly relevant. This finding will be discussed along with our ERP evidence in a sub-sample of children showing that LSI deficits likely arise from multiple underlying causes, supporting a multi-componential view of dyslexia.