DIFFERENCES IN SEMANTIC EVENT-RELATED POTENTIALS IN LEARNING-DISABLED, NORMAL, AND GIFTED-CHILDREN

Cortical event-related potentials (ERP) were recorded over FZ, CZ, and PZ scalp sites in 15 learning-disabled (LD), 14 gifted (G), and 13 no rmal control (N) children of ages 8-12. The common stimulus consisted of nouns presented 80 percent of the time; the target stimulus of anim al names presented 20 per cent of the time. ERPs were averaged over su bjects from 180 msec pre-stimulus to 900 msec post-stimulus. Principal components analysis was used to determine if there were amplitude dif ferences at different post-stimulus latencies as a function of conditi on. Differences in ERP's between groups (LD, gifted, and controls), sc alp locations, and common versus target stimuli were analyzed by ANOVA s. P3, Late, P2, and N1 components represented by four factors were id entified. Significant differences between G and LD and the N and LD gr oups were found target stimulus at all central locations for the P3 co mponent. Differences were found centrally between G and LD, G and N, a nd N and LD groups for the P2 component centrally. Other differences w ere found for the N1 and late components. These differences could be i nterpreted as a deficit in either attentional mechanisms or informatio n processing for the LD group.