The Swedish WAIS-R factor structure and cognitive profiles for adults with dyslexia

Factor analysis of the Swedish version of the Wechsler Adult Intelligence Scale-Revised (WAIS-R) on a group of 88 adult individuals with dyslexia showed a three-factor structure with a verbal comprehension (VC) factor, a perceptual organization (PO) factor, and a freedom from distractibility (FD) factor. The results of this factor analysis support earlier findings from factor analyses of adults in the original U.S. normative sample and in different clinical groups. The profile of scores for the sample of individuals with dyslexia showed the expected pattern, with PO highest and FD lowest. The predicted pattern was also observed using Bannatyne's recategorization of WAIS-R subtests. As has been true for other typical and exceptional samples, women scored significantly higher than men on the Digit Symbol subtest. Related to this gender difference, Digit Symbol scores proved to be sensitive to problems associated with dyslexia only for men with dyslexia. Also, education level was shown to be related to verbal (V)-performance (P) IQ discrepancy, with larger P > V differences observed for participants with fewer years of formal schooling. Regardless of these gender and education differences, the characteristic factor score and Bannatyne patterns were identified for both men and women and for three different subsamples categorized by educational level.