The role of attention on the intelligence test scores of patients with attention deficit hyperactivity disorder

Abstract

In comparison to healthy children, cases with Attention Deficit Hyperactivity Disorder (ADHD) score lower at subtests of Wechsler Intelligence Scale for Children-Revised (WISC-R). According to the research hypothesis, the lower scores in subtests of WISC-R originate from disordered attentional processes. Sample (age range: 72-149 months) included 143 healthy boys and 215 boys in the ADHD group (Predominantly Attention Deficit: n = 72, Predominantly Hyperactivity/Impulsivity: n = 41, Combined: n = 102). Participation was conditional to informed consent of the parents and approval of the participants/cases. Cases with comorbidity and medication were not included in the DEHB group. Intelligence was measured using WISC-R, types of attention were measured using Stroop Test TBAG version, Cancellation Test and Visual Aural Digit Span Test-B Form. In line with the types of attention that they represent, neuropsychological test scores loaded on three different factors. Except the digit span score, WISC-R scores loaded on a fourth factor. Scores of the DEHB group was significantly lower than that of the healthy control group in 9 out of 12 WISC-R scores. When types of attention were statistically controlled, 7 of the previously significantly different scores ceased to exist. These findings show that the lower scores of the DEBB group in subtests of WISC-R should not be explained by deficits in the cognitive processes that the subtests specifically intend to measure. These findings support the hypothesis that the lower scores are due to a basic inability to attend and are thus secondary to this disorder.