Cognitive profiles of groups of poor readers and dyslexic children on the British Ability Scales.

Two samples of children with reading difficulties--145 poor readers and 121 dyslexic children--were tested on the British Ability Scales (BAS). The poor readers were classified, using Rutter & Yule's (1975) criteria, into children with specific reading retardation and general reading backwardness. These children's profiles of scores on the BAS were also entered into a cluster analysis which provided some confirmation of the validity of the Rutter & Yule classification. The BAS scores of the dyslexic children were also entered into a cluster analysis. Three groups were identified: 30 with mixed visuo-spatial and linguistic processing problems, 52 with sequential processing problems, and 39 with problems in the holistic retrieval of information. It was concluded that the data lend support to the view that children with specific reading retardation, and dyslexic children in particular, are not homogeneous in their cognitive profiles. Finally, each group identified above was analysed for fit to the Lawson & Inglis (1985) principal components model of learning disability. The fit to the model for most groups was poor. It was concluded that a model which implicates left hemisphere aetiology for all LD children is inadequate. Some benefit, however, is likely to accrue from the more rigorous definition of specific subtypes, and in this endeavour the BAS appear to offer a useful advance in such assessment and identification.