Interpreting the Leiter IQ: performance profiles of young normal and language-disordered children

Language-disordered children with normal range performance IQ may nevertheless evidence cognitive deficits. This suggests the need for content validity studies of performance tests of intelligence. In the current investigation, items from the Leiter International Performance Scale (LIPS) were analyzed for their conceptual versus perceptual character; these item groupings were then used to create intratest LIPS profiles for 16 language-disordered children and 16 children with normal language, aged 4:4-5:5, who were matched for CA, sex, and Leiter IQ. Interjudge (N = 4) reliability for determination of item type was 96%, and the results of the item analysis revealed that 65% of LIPS items in the 2-8 year range were perceptual in nature. A repeated-measures ANOVA indicated that subjects performed relatively better on the perceptual items regardless of group (p less than .01) and that there were no significant group differences. Analysis of individual subject profiles, however, revealed accentuated intratest profiles for two of the language-disordered subjects and reversal of the dominant perceptual greater than conceptual trend for four of the language-disordered subjects. These results indicate that LIPS scores for children under age 8 primarily represent their ability to assess the physical characteristics of visual stimuli and may not adequately reflect the transforming, interpretive aspects of nonverbal cognition.