A COMPARATIVE-STUDY OF ERP CORRELATES OF PSYCHOMETRIC AND PIAGETIAN INTELLIGENCE MEASURES IN NORMAL AND HYPERACTIVE-CHILDREN

Verbal and performance scores of the Wechsler Intelligence Scale for C hildren-Revised (WISC-R 1981) and of a Piagetian battery, the Cognitiv e Development Scale for Children (EDC 1984), were obtained on 30 norma l control and 19 hyperactive 6-8-year-old children. Amplitudes and lat encies of a fronto-central P250 and of the parieto-occipital N250, P35 0 and P500 were measured concurrently in 4 categorization tasks derive d from tests of the WISC-R and EDC batteries. Spearman correlations we re computed between the intelligence and the ERP factor scores. Result s showed that age-related and age-corrected Wechsler's scores were cor related with similar ERP changes (reduced amplitude, decreased latency ). With regard to the amplitude changes, each type of intelligence was associated with a specific ERP pattern. The verbal scores were correl ated with the P350 and the P500 amplitudes, and the performance scores with the frontal P250 and occipital N250 amplitudes. By contrast, Pia getian development and intelligence scores yielded ERP correlates in t he opposite direction: P500 amplitude was negatively correlated with r aw EDC scores, but positively with scaled EDC scores. In addition, Pia getian intelligence was not related to the general peak latency decrea se with age. In hyperactive children, additional negative correlations were found between P250 amplitude and the subjects' verbal test score s. Correlations with some performance tests that were negative in norm al controls, were positive in hyperactive children. In addition, laten cy-based correlations found in normal controls were lacking in hyperac tive children. These findings provide strong evidence that intelligenc e comprises different components related to different subsets of cogni tive processes, as indexed by different ERP waves. They also suggest t hat the development and intelligence do not always rely on the same ch anges, and that intelligence forms may not be referred to the same use of the same processes in hyperactive and normal children.