[Quantitative analysis of the electroencephalogram in healthy school-age children].

Topography of EEG power spectra in a sample of 72 healthy children aged 7 to 15 years, was studied. The children were volunteers, satisfying general criteria of normality. The EEGs were recorded at 16 scalp locations in subjects with closed eyes and measured in monopolar recording on a split screen of a system for video EEG monitoring. Each signal of EEG channels was digitized with 12-bit resolution and processed by a PC computer. The raw EEG was transformed by fi-time domain into the frequency domain using the fast Fourier transforms. In-transformed absolute power and relative power were used as parameters. In the present study it was shown that total power was mainly influenced by alpha power. Maximal delta activity exhibited in anterior and posterior derivations, while minimal activity was measured in central and mid-temporal locations. Theta power was mostly pronounced in posterior derivations. Beta-1 band activity was maximal in posterior and minimal in anterior derivations. Significant power decrease in beta-2 power was also characteristic of posterior locations. Diagrammatic presentation of In-transformed absolute power over brain regions (frontal, central, midparieto-occipital and temporal) gave a summary of distributions shown earlier. Most of the relative powers were found in alpha band, especially in parieto-occipital region.