Table 1.

Sample demographics of 6- and 12-month-old participants

	6-month dataset		12-month dataset
	HR-ASD, n = 14	HR-noASD, n = 40	HR-ASD, n = 27	Matching HR-ASD, n = 14	HR-noASD, n = 40
Sex	8 M, 6 F	19 M, 21 F	17 M, 10 F	8 M, 6 F	18 M, 22 F
Child ethnicity (%)
Caucasian	92.9	97.5	77.8	92.9	95
Hispanic/Latinx	21.4	2.5	14.8	21.4	7.5
Asian American	0	0	3.7	0	0
African American	0	0	3.7	0	0
Multirace	7.1	2.5	14.8	7.1	7.1
Mean household income ($1000s)	65‑75	65‑75	65‑75	65‑75	65‑75
Mean maternal education (%)
< 4-year college	28.6	27.5	37	28.6	25
= 4-year college	35.7	15	37	42.9	12.5
> 4-year college	35.7	57.5	25.9	28.5	62.5
EEG HAPPE metrics (mean [SD])
Length of raw EEG (s)	701.3 [212.9]	693.6 [220.7]	763.7 [213]	735.8 [225.2]	764.8 [209.5]
Good channels (%)	93.1 [4.1]	94.2 [4.7]	92 [4.8]	91.6 [4.7]	92.8 [5.5]
Rejected components (%)	47 [13]	44.1 [13]	43.8 [10]	42.6 [8.4]	43.4 [12.2]
EEG variance retained (%)	61.6 [13.3]	64.9 [17.4]	66.5 [12.6]	70.1 [10.5]	69.6 [16]
Mean retained artifact probability	0.16 [0.05]	0.17 [0.03]	0.15 [0.05]	0.16 [0.05]	0.15 [0.04]
Median retained artifact probability	0.13 [0.06]	0.15 [0.06]	0.1 [0.07]	0.11 [0.07]	0.1 [0.06]