Nash, H., Gooch, D., Hulme, C., Mahajan, Y., McArthur, G., Steinmetzger, K. & Snowling, MJ. (2017). Are the literacy difficulties that characterize developmental dyslexia associated with a failure to integrate letters and speech sounds?. Developmental Science,20(4), 1-16. United Kingdom: Blackwell Publishing Ltd. Retrieved from https://doi.org/10.1111/desc.12423
The ‘automatic letter-sound integration hypothesis’ (Blomert,) proposes that dyslexia results from a failure to fully integrate letters and speech sounds into automated audio-visual objects. We tested this hypothesis in a sample of English-speaking children with dyslexic difficulties (N = 13) and samples of chronological-age-matched (CA; N = 17) and reading-age-matched controls (RA; N = 17) aged 7–13 years. Each child took part in two priming experiments in which speech sounds were preceded by congruent visual letters (congruent condition) or Greek letters(baseline). In a behavioural experiment, responses to speech sounds in the two conditions were compared using reaction times. These data revealed faster reaction times in the congruent condition in all three groups. In a second electrophysiological experiment, responses to speech sounds in the two conditions were compared using event-related potentials (ERPs). These data revealed asignificant effect of congruency on (1) the P1 ERP over left frontal electrodes in the CA group and over fronto-central electrodes in the dyslexic group and (2) the P2 ERP in the dyslexic and RA control groups. These findings suggest that our sample of English-speaking children with dyslexic difficulties demonstrate a degree of letter-sound integration that is appropriate for their reading level, which challenges the letter-sound integration hypothesis.
Institute for Learning Sciences and Teacher Education
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