SUBTYPES OF READING-DISABILITY - VARIABILITY AROUND A PHONOLOGICAL CORE

Eight measures of cognitive and language functions in 232 children wer e subjected to multiple methods of cluster analysis in an effort to id entify subtypes of reading disability. Clustering yielded 9 reliable s ubtypes representing 90% of the sample, including 2 nondisabled subtyp es, and 7 reading-disabled subtypes. Of the reading-disabled subtypes, 2 were globally deficient in language skills, whereas 4 of the 5 spec ific reading-disabled subtypes displayed a relative weakness in phonol ogical awareness and variations in rapid serial naming and verbal shor t-term memory. The remaining disabled subtype was impaired on verbal a nd nonverbal measures associated with rate of processing, including ra te and accuracy of oral reading. Studies showed evidence for discrimin ative validity among the 7 reading-disabled subtypes. Results support the view that children with reading disability usually display impairm ents on phonological awareness measures, with discriminative variabili ty on other measures involving phonological processing, language, and cognitive skills.