Margaret J. Snowling,1 and Charles Hulme2
This article reviews our understanding of reading disorders in children and relates it to current proposals for their classiﬁcation in DSM-5. There are two different, commonly occurring, forms of reading disorder in children which arise from different underlying language difﬁculties. Dyslexia (as deﬁned in DSM-5), or decoding difﬁculty, refers to children who have difﬁculty in mastering the relationships between the spelling patterns of words and their pronunciations. These children typically read aloud inaccurately and slowly, and experience additional problems with spelling. Dyslexia appears to arise principally from a weakness in phonological (speech sound) skills, and there is good evidence that it can be ameliorated by systematic phonic teaching combined with phonological awareness training. The other major form of reading difﬁculty is reading comprehension impairment. These children read aloud accurately and ﬂu- ently, but have difﬁculty understanding what they have read. Reading comprehension impairment ap- pears to arise from weaknesses in a range of oral language skills including poor vocabulary knowledge, weak grammatical skills and difﬁculties in oral language comprehension. We suggest that the omission of reading comprehension impairment from DSM-5 is a serious one that should be remedied. Both dyslexia and reading comprehension impairment are dimensional in nature, and show strong continuities with other disorders of language. We argue that recognizing the continuities between reading and language disorders has important implications for assessment and treatment, and we note that the high rates of comorbidity between reading disorders and other seemingly disparate disorders (including ADHD and motor disorders) raises important challenges for understanding these disorders.
Keywords: Reading disorders, language disorders, dyslexia, reading comprehension impairment, intervention.