Aperiodic and Hurst EEG exponents across early human brain development: a systematic review

Abstract

AbstractIn electroencephalographic (EEG) data, power-frequency slope exponents (1/fβ) can provide non-invasive markers ofin vivoneural activity excitation-inhibition (E:I) balance. E:I balance may be altered in neurodevelopmental conditions; hence, understanding how 1/fβevolves across infancy/childhood has implications for developing early assessments/interventions. This systematic review (PROSPERO-ID: CRD42023363294) explored the early maturation (0-26yrs) of resting-state EEG 1/fmeasures (aperiodic [AE], power law [PLE] and Hurst [HE] exponents), including studies containing ≥1 1/fmeasures and ≥10 typically developing participants. Five databases (including Embase and Scopus) were searched during March 2023. Forty-two studies were identified (Nparticipants=3478). Risk of bias was assessed using the Quality Assessment with Diverse Studies tool. Narrative synthesis of HE data suggests non-stationary EEG activity occurs throughout development. Age-related trends were complex, with rapid decreases in AEs during infancy and heterogenous changes thereafter. Regionally, AE maxima shifted developmentally, potentially reflecting spatial trends in maturing brain connectivity. This work highlights the importance of further characterising the development of 1/fmeasures to better understand how E:I balance shapes brain and cognitive development.