Predictors of exception word and nonword reading in dyslexic children: The severity hypothesis.

The classification of dyslexic children into discrete subtypes yields a poor description of the dyslexic population at large. Multiple regression methods were used to examine continuous variation in component reading subskills (nonword and exception word reading) and their underlying cognitive skills within a group of 59 9-15-year-old dyslexic children. Two measures of phonological skills contributed unique variance to nonword reading: phonological processing and verbal short-term memory skills. In contrast, the only unique predictor of exception word reading was reading experience. The results are discussed within a connectionist framework that views the decoding deficit in dyslexia as stemming from poorly specified phonological representations. The extent of the nonword reading deficit is determined by the severity of the underlying phonological impairment. In contrast, exception word reading is influenced more by print exposure.