Exploring background aperiodic electroencephalography (EEG) activity in the Bucharest Early Intervention Project

Aperiodic activity is a background arrhythmic component of electroencephalogram (EEG) that is present in the power spectrum and characterized by an aperiodic offset and an aperiodic exponent. These components have been proposed as a marker of brain maturation, reflecting alterations in excitatory-inhibitory (E:I) balance and exhibiting developmental changes over time. Currently, there is limited understanding regarding how aperiodic activity changes over the course of an individual's life, particularly from early childhood to adolescence, a period when the brain undergoes significant structural and functional transformation. More importantly, considering that brain development is affected by early experience, there is no evidence on how early adversity might affect these parameters. Here, we examined the developmental trajectories of aperiodic activity from EEG data collected in the Bucharest Early Intervention Project, from early childhood to mid adolescence (from 42 months of age up to 16 years old). We examined the effects of a history of early adversity and the impact of early intervention on background aperiodic EEG activity. Surprisingly, we found little influence of a history of adversity or early intervention on these characteristics of the signal. Rather, we found nonlinear age-related trajectories in both aperiodic offset and aperiodic exponent and sex differences in the trajectory for aperiodic offset (but not exponent). These findings provide information on the maturational patterns and trajectories of brain development from early childhood to mid adolescence and how background aperiodic activity describes one aspect of EEG development. (PsycInfo Database Record (c) 2025 APA, all rights reserved).