Varieties of reading disability : Phonological and orthographic word decoding deficits and implications for interventions

Abstract: The general aim of this thesis was to examine variations in the word decoding skills of reading disabled children. These variations were related to possible cognitive, developmental, and environmental causes of reading disability. Possible implications for educational interventions were also analysed. The thesis critically examines the inclusion of the concept of intelligence in the definition of developmental dyslexia. It is suggested that variations in word decoding skills should offer a more solid basis for a study of varieties of reading disability. The empirical studies showed that a) in young children there was a shift from phonological to orthographic word decoding; b) phonological type children (weak in phonological decoding) were characterised by specific phonological deficits; c) surface type children (weak in orthographic decoding) showed more global cognitive deficits suggesting a general developmental delay; d) surface type children showed impaired visual implicit memory for words, which might be associated with limited print exposure; e) an improvement in phonological awareness only transferred to an improved text reading ability for some reading disabled children; f) children who did not benefit from a phonological intervention seemed to rely on orthographic word decoding in text reading. Thus, the thesis suggests that variations in phonological and orthographic word decoding skills offer a useful basis for the study of varieties of reading disability and that educational interventions should pay regard to what the child is already attempting to do when reading.