Normal and Abnormal Reading: Phonology and Dyslexia

Abstract

Background:In this article we review some experimental, modeling, and neuropsychological findings on normal and abnormal reading. We mainly focus on single word reading as a mature area in scientific studies of reading. Purpose:The aim of the current review study was to show the importance of theories and models that have taken into account the cognitive, specifically phonological, processes in reading. Looking at factors playing roles in reading can be helpful in tackling literacy problems. Method:Interdisciplinary studies on reading have focused on the role of phonology as revealed by psychological experiments, lesion studies, connectionist modeling. Some words can be recognized and produced easier than others, as shown by the differences between acquired and developmental dyslexia and between surface and deep (phonological) dyslexia. Findings: The dual-route model of reading assumes two routes for single word reading: a lexical route for reading exception words, such as have or pint in which no direct correspondences exist between print and sound, and a sub-lexical route for reading regular words such as save and mint and non-words such as nust. Consequently, impairment to each one of these routes leads to a specific kind of dyslexia, discussed latter. The connectionist model of word consists just one process but can successfully read regular and irregular words as well as non-words. Results: Phonological dyslexia is caused by an impairment, either acquired or developmental, leading to difficulties in reading non-words. Another form of dyslexia is known as surface dyslexia which is caused by impairment, again acquired or developmental, leading to difficulties in reading exception words. Implications: These studies even go beyond the phonological awareness. The effect of training has also been shown by connectionist modeling, where the effect of intervention in phonological representation declines sharply once training to read has begun. Originality/Value: Taken together, recent studies have shown the importance of phonology in reading, despite ongoing debates about the true nature of the phonological deficit in poor reading.