Differences Between Preterm and Full‐Term Infants in Electroencephalogram Power Spectral Density Slope

A growing body of literature suggests that power spectral density (PSD) slope, measured using electroencephalography (EEG), might reflect synaptic activity and be a useful marker of early brain development. The objective of this article is to identify differences between preterm and full-term infants in PSD slope in active and quiet sleep. This is a secondary analysis of two studies, including premature (N = 33) (30 0/7 and 36 0/7 weeks' gestation) and full-term infants (N = 22). EEG was performed at near term-equivalent age in premature infants and within 36 h after birth in full-term infants. The natural log of the EEG power spectrum was plotted versus the natural log of the frequency spectrum. To estimate PSD slope, the power law exponent derived from the slope of the log(power) versus log(frequency) was calculated for the 1-20 Hz range and the 21-40 Hz range. Linear regression models were fit for each region in active and quiet sleep to examine the association between the PSD slope and infant age group. Preterm versus full-term infants demonstrated a less negative slope across multiple brain regions in active and quiet sleep. PSD slope may be an early measure of altered brain development in premature infants.