Electrophysiological assessment of the brain function in term SGA infants.

Small for gestational age (SGA) infants are defined as babies having a birth weight below the 10th percentile for gestational age. A great number of studies have shown that children with SGA have an increased risk of impaired neurodevelopment. Electroencephalography (EEG) is an excellent method for measuring brain maturation in newborns. In this study, the effect of SGA on the maturation of cerebrocortical electrographic activity was investigated by the EEG and also analyzed with power spectral analysis. Serial EEGs were performed in 40 term SGAs, and 20 term appropriate for gestational age (AGA) infants in 1st week, 1st and 3rd month. Power spectral analysis was performed quantitatively in five channels (Fp1-C3, C3-O1, Fp2-C4, C4-O2, and Cz-C4 channels). Amplitude levels of the SGA group were significantly lower than the AGA group in all records. Delta frequency was the major frequency component in the groups. Delta frequency activities in the midline vertex region were decreased in the AGA group with increasing postconceptual age while the activities of the SGA group were increased. Contrarily, beta frequency activities in the midline vertex region were increased in the AGA group with increasing postconceptual age while these activities of the SGA group were decreased. Theta frequency activities in the fronto-central regions were lower in the SGA group. In terms of the vertex, k-complex, and sleep spindle, there was no difference between the two groups. We conclude that cerebrocortical electrophysiological maturation has been delayed in term SGA infants during the first three months of postnatal life.