EEG slow frequency and WISC-R correlates

On the basis of slow frequency indices obtained from computerized EEG assessments, 36 children were ranked the highest and 23 the lowest in a heterogeneous population of children involved in a brain-behavior assessment program. WISC-R results show the high or excess slow frequency group to have low verbal and normal performance subtest scores, while those with the least slow frequency activity were above normal on verbal and performance scores. Discriminant function analyses of the WISC-R profiles significantly separated the two EEG groupings, with the Information Subtest and Verbal IQ the best discriminating measures. The results suggested that diffuse EEG slow frequency reflected a maturational lag. Cluster analyses showed that the subtest profile was constant independently of IQ. Other findings indicated that the presence of excessive slow frequency activity was associated with less electrophysiological and psychometric differentiation.This work was supported by a contract awarded by The Ontario Ministry of Community and Social Services, a contract awarded by The Ontario Ministry of Education, a grant awarded to W. Corning by The National Science and Engineering Research Council, and by a University of Waterloo Faculty Research grant and a SSHRC leave fellowship to R. A. Steffy. The authors wish to acknowledge the assistence of K. Blom, B. Jones, J. Free, J. Washburn, L. MacDonald, G. Verspagen, the secretarial department, and the shop staff of the University of Waterloo, Psychology Department.