Converging evidence for phonological and surface subtypes of reading disability.

Abstract

Using regression-based procedures introduced by A. Castles and M. Coltheart (1993), the authors identified 17 phonological and 15 surface dyslexics from a sample of 68 reading-disabled 3rd-grade children by comparing them to chronological-age (CA) controls on exception word and pseudoword reading. However, when the dyslexic subtypes were defined by reference to reading-level (RL) controls, 17 phonological dyslexics were defined but only 1 surface dyslexic. When the CA-defined subtypes were compared to RL controls, the phonological dyslexics displayed superior exception word reading but displayed deficits in pseudoword naming, phonological sensitivity, working memory, and syntactic processing. The surface dyslexics, in contrast, displayed a cognitive profile remarkably similar to that of the RL controls.