Hyperlexia in a 4-year-old boy with Autistic Spectrum Disorder

This paper presents a case study of a 4-year-old boy with Autistic Spectrum Disorder and a mental age of approximately 1:5 who demonstrates precocious oral-reading behaviour in the absence of spontaneous speech. Tests of reading regular and irregular words, pseudowords, homographic heterophones, single sentences and texts were carried out. Performance on a variety of reading tasks suggests the ability to use grapheme–phoneme correspondences and whole word reading for decoding single words. In addition, successful reading of some homographic heterophones and semantic paraphrasing of texts suggests a level of lexical, syntactic, semantic and pragmatic development far beyond his mental or chronological age. The realisation of highly developed reading ability is paradoxical in the context of profound impairment in cognitive development and an absence of spoken language.