Comparative analysis of the EEG in babies in the first month of life with gestation periods of 30-42 weeks.

The aim of the present work was to compare measures of the power spectra, indexes, and coherence of the EEG in term and preterm infants in the first month of life. Six groups of children were investigated, born at 1) 30-32, 2) 33-34, 3) 35-36, 4) 37-38, 5) 39-40, and 6) 41-42 weeks of gestation; there were 10 in each group. The power of the delta frequencies was maximal in group 5. The power of theta frequencies was greatest in group 3. The theta frequencies index was higher in groups 2, 3, and 4. Alpha frequency power was greater in group 2. The index of alpha frequencies was greater in groups 1, 2, and 3. The indexes of beta1 and beta2 frequencies was greater in groups 1, 2, and 4. The largest number of coherence links in the delta, theta, and alpha frequencies were seen in group 6. Group 2, as compared with group 5, had more coherence links in the delta frequencies in the posterior and posterocentral areas, as well as more intrahemisphere synchronization in the theta and alpha frequencies. The results obtained here showed that EEG power spectra, indexes, and coherence depended on the gestation age at the time of birth, though this relationship was nonlinear.