EEG POWER SPECTRA OF NORMAL PREADOLESCENT TWINS - GENDER DIFFERENCES OF QUANTITATIVE EEG MATURATION

To determine developmental changes of quantitative EEG maturation, we investigated the electroencephalogram (EEG) power spectra in a sample of 72 pairs of healthy twins (144 subjects, 75 girls and 69 boys) rang ing in age from 7-15 years. Main spectral parameters were measured in 16 EEG channels. The statistical significance of differences in the EE G power spectra was compared in relation to age and gender. Gender dif ferences were tested by comparing the EEG parameters of boys and girls in the whole sample and separately in the subgroup of dizygotic twins of the opposite sex (DZO twin pairs). A statistically significant dec rease of absolute power occurred with increasing age. A significant re distribution of relative power also appeared in higher age, mainly con sisting of a progressive increase of alpha 2 power inversely related t o relative alpha 1 and theta power. Polynomial regression models of th e relation between alpha 2 and theta relative power with age were best described by a 5-order function. The mean frequency of activity acros s all spectra also increased with age and was maximal in the eldest su bjects (13-15 years), with a significantly higher mean frequency of al pha 2 power in females. Similar age and gender differences were less m arked in the subgroup of DZO twin pairs. The topographic distribution of spectral bands in normal subjects suggested an earlier maturation o f midparietal or occipital than frontocentral regions, and indicated t hat the growth spurt does not occur simultaneously over homologous rig ht and left hemisphere regions at the same age. (C) 1998 Elsevier, Par is.