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Sketchpad Series

Developmental trajectories of EEG rhythmic oscillatory activity in children 2-44 months of age

Poster Session F - Tuesday, April 1, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Haerin Chung^1,2 (haerin.chung@childrens.harvard.edu), Winko W. An^1,2, Charles A. Nelson^1,2,3, Carol L. Wilkinson^1,2; ¹Boston Children’s Hospital, ²Harvard Medical School, ³Harvard Graduate School of Education

Introduction: Transient changes in spectral power within the theta/alpha range (4–12 Hz) are observed in early childhood, with studies reporting a gradual shift in peak frequency between 5-to-10Hz. Recent findings report transient double peaks (5.5-and-9.5Hz) at 2–4 months, with the higher 9.5Hz peak disappearing by 6 months. Peaks observed in the power spectra are thought to reflect neural oscillatory activity; however, peaks may arise from either irregular (bursty) or sustained (rhythmic) activity. Thus, transition from double to single peak may signal maturational changes of irregular and sustained oscillatory activity. This study aims to characterize developmental changes in rhythmic properties over time and clarify whether transient double peaks in spectral power derive from bursty or rhythmic activity in the first months of life. Methods & Preliminary results: We will analyze resting-state EEG data from 600 participants tracked longitudinally from 2-to-44 months across four studies. Lagged coherence (LC) will be computed to explore the rhythmicity of the signal across 2-40Hz, in 0.2Hz steps from 1-to-3 lags. Preliminary analyses suggest that rhythmic posterior alpha begins to emerge around 5–6 months, with peak frequency and magnitude of LC increasing with age. Distinct peaks at 5-and-10Hz were observed between 2-to-5 months but were decreased by 12-months as the sustained oscillatory alpha stabilized between 6-9Hz. This implies the possibility of two independent transient oscillations with distinct rhythmic properties present early in development, which decrease with maturation as the mature rhythmic alpha emerges. Generalized additive mixed models will be used to assess changes within-subjects over time.

Topic Area: METHODS: Electrophysiology