Development of the electroencephalographic rhythms of wakefulness in healthy infants during their first year

Broad-band automated analysis was performed of the delta-, theta-, alpha- and beta EEG-rhythms from F3 and F4, C3, and C4, O1, and O2, T3 and T4 of healthy awake infants with open eyes. The data on the integrated amplitude of the above-mentioned rhythms were obtained in volt. sec. The age-determined changes in the mean values of this parameter were proved to be different in scope and in character. Generally speaking, the delta activity was not substantially changed in any of the areas indicated above at the end of the first year of life, compared with the first three months; the theta activity was substantially higher everywhere, with the exception of T3 and O2; the alpha activity was not increased only in T3 and T4, whereas the beta 1 activity was not increased in F3 and T3. Greatest changes were observed in the theta activity of the two central regions and O1, for the alpha activity--in the two occipital and the two central regions, for beta 1--generally in the right hemisphere. This state was attained predominantly through a gradual rise in the integrated amplitude of the respective rhythms, though there was also an abrupt development, mainly in the central and occipital regions.