EEG power and coherence in children with educational problems.

SUMMARY This study deals with the quantitative EEG (QEEG) of children attending schools for the mentally retarded and learning disabled. Questions are in which way do the EEGs of these children differ from normal development and whether deviations are restricted to a subgroup of children. The topographic distribution of EEG power is of particular interest. Based on a sample of n = 158 normal children, age-standardized values of absolute power (delta, theta, alpha 1, alpha 2, beta 1, beta 2 at F4, F3, C4, C3, CZ, PZ, O2, O1) and of coherence are computed for all children. The topographic distribution is assessed by analysis of variance (ANOVA) and by a principal component approach. The EEG of children with educational problems differs substantially from normal development in the slow bands and differs less in the fast bands. Deviations affect a subgroup of children, mainly children attending a school for the mentally retarded. Topographic distribution is an important factor in all bands. Coherence analysis leads to rather weak results that lack a clear interpretation. The QEEG is useful for understanding neurophysiological development in children with educational problems as a group more than individually. Parameters of topographic distribution provide strong additional information to power itself.