B - 60 A Comparison of Processing Speed and Impulsivity in Predicting Working Memory Ability in Children.

Abstract

Our objective was to contrast two predictors of working memory performance in children. Working memory (WM) is related to processing speed and to inhibitory control in typically developing adults; however, research on this topic is relatively scarce in children. Research comparing these predictors is even more scant in children. Therefore, this study examined how well processing speed and impulsivity predict WM performance in a mixed sample in order to have a full range of functioning in these areas. Participants included 228 children from a community sample (ages 8-11years; 85.1% White; 55.6% boys) attained through NIH-funded projects (R03HD048752, R15HD065627). They were diagnosed with ADHD (35.0%), RD (14.4%), comorbid RD/ADHD (18.5%), other diagnoses (7.4%), or were typically developing (24.7%). Processing speed was assessed with the WISC-IV Coding scaled score. Items measuring impulsivity from the BASC-2 Hyperactivity scale were summed to form the impulsivity variable. The Children's Memory Scale (CMS) Sequences subtest was used to measure WM. A multiple linear regression analysis was run with Coding and impulsivity as the IVs and Sequences as the DV. The overall equation was significant (adjusted R2 = 0.097, F(2, 228) = 13.349, p < 0.001). Coding predicted WM performance (Beta = 0.317, p < 0.001). Impulsivity, however, was not significant (Beta = -0.042, p = 0.503). Results indicate that processing speed is the better statistical predictor of working memory performance in a mixed sample of children. More research on the relationship between impulsivity and WM in children is needed, as our insignificant finding on it conflicts with the limited available literature.