TABLE 4.

Variables that most contributed to the heterogeneity and homogeneity among preschool-aged children with autism spectrum disorder and those with subthreshold characteristics in the Study to Explore Early Development Phase1 and Phase2

		Autism spectrum disorder		Subthreshold characteristics
		SEED1	SEED2	SEED1	SEED2
Heterogeneity Dimension 1: Dysregulation	Anxiety/depression	+	+	+	+
	Sleep problems	+	+	+	+
	Aggression	+	+	+	+
	No sensory dysfunction	+	+
	Emotional reactivity			+	+
Heterogeneity Dimension 2: Developmental abilities	Expressive language skills	+	+	+	+
	Receptive language skills	+	+	+	+
	Fine motor skills	+	+
	Visual reception skills	+	+
	Visual reception delays			+	+
Homogeneity	Sensory dysfunction	+	+
	Age of walking 15 months or younger	+	+
	Absence of epilepsy/seizure disorder	+	+	+	+
	Absence of developmental regression			+	+
	Absence of moderate–severe ASD symptoms			+	+

Note: Developmental skills in Dimension 2 in the average range unless otherwise noted.