Nonlinguistic Deficits of Children With Language Disorders Complicate the Interpretation of Their Nonverbal IQ Scores

Abstract

This study supports the hypothesis that the nonlinguistic deficits of children with language impairment (LI) adversely affect their responses to specific item types represented on nonverbal IQ tests (Kaufman Assessment Battery for Children-Nonverbal Scale, Leiter International Performance Scale, and Matrix Analogies Test-Short Form). Twelve children with normal language (NL) and 12 with LI (8 to 10 years of age), matched for gender and age, served as subjects. A two-way mixed ANOVA revealed main effects ( p <.05) for group and for test, and a Tukey HSD post-hoc analysis indicated significant between-group differences for each test. Robust effect sizes were found with item types judged a priori to assess deficit areas in children with LI. The extent to which certain item types correlated with IQ scores differed by subject group. The findings call into question the use of nonverbal IQ scores as measures of general intelligence or potential as well as their use to qualify children with LI for clinical services.