Fig. 3.

3-month frontal EEG power by outcome group. a, b Frontal binned power spectral density (log10 transformed) at 3 months of age for LRC−, HRA−, and HRA+ outcome groups for each frequency band, using a average-referenced data and b Laplacian-referenced data. c Frontal unbinned group-median power spectra (solid line, median; shaded area, 25th–75th percentile) showing EEG power at 3 months of age across all frequencies in HRA+ and HRA− groups, for average-referenced data. (Red line, HRA+; green line, HRA−). d Differences in frontal unbinned group-median power spectra at 3 months of age, presented with 95% CI from the bootstrap analysis (average-referenced data) (purple line, 2.5th percentile; orange line, 97.5th percentile). EEG power is similar across all frequencies for the HRA+ as compared to the HRA− group. e, f Same analysis as (c, d), for Laplacian-referenced data. There are no significant differences in power in the HRA+ group compared to the HRA− group at any frequency. LRC− = low-risk control, no ASD; HRA− = high-risk for autism, no ASD; HRA+ = high-risk for autism, with ASD