Table 1 Characteristics of Young Children with ASD

		Child 1	Child 2
Age		5 years 11 months	4 years 1 month
Sex		Female	Male
K-CDI1)		Socialization: 18.5 monthsSelf-Help: 5 years 2 monthsGross Motor: 5 years 10 monthsFine Motor: 4 years 10 monthsExpressive Language: 2 years 2 monthsLanguage Comprehension: 2 years 4 months	Socialization: 16.5 monthsSelf-Help: 3 years 5 monthsGross Motor: 2 years 11 monthsFine Motor: 2 years 11 monthsExpressive Language: 14 monthsLanguage Comprehension: 2 years 1 month
CARS-22)		34.5 (Mild-to-Moderate)	40 (Severe)
SCQ3)		23	26
CIBT4)		Very low	Very low
Social Interaction	Attention	• Explores surrounding toys and plays with new or preferred ones.• Observes and imitates peer play behaviors.• Primarily engages in independent, solitary play with toys.	• Explores surrounding toys and plays with preferred ones.• Observes and imitates peers playing with preferred toys.• Primarily engages in independent, solitary play with toys.
	Responsive Behavior	• Makes eye contact when presented with objects.• Complies with two-step directions from adults.• Responds to questions but often exhibits no reaction.	• Rarely makes eye contact even when presented with preferred objects.• Complies with one-step directions from adults.• Seldom responds to others’ questions.
	Initiative Behavior	• Requests preferred items/activities using 2-3 word interrogative expressions.• Gazes at peers to make requests.	• Grabs preferred toys without communicative intent (verbal or non-verbal).• Gazes at peers to make requests.
Communication		• Communicates using sentences composed of listed words.• Complies with requests from adults or peers.• Frequently uses rising intonation (interrogative form).	• Produces vocalizations like babbling.• Complies with simple directions from adults.• Exhibits hand-leading behaviors for communication.
Play		• Prefers symbolic/pretend play (e.g., hair salon, taking photos).• Sits next to peers who are engaging in preferred play and watches them.• Uses toys in a functional/typical manner.• Primarily engages in solitary play.	• Prefers manipulative play (e.g., car tracks, building blocks).• Sits next to peers who are engaging in preferred play and watches them.,break/>• Uses toys in a functional/typical manner.• Primarily engages in solitary play.

K-CDI (Korean Child Development Inventory): Borderline range (-1.5 to -2.0 SD), Delayed range (below -2.0 SD).
CARS-2 (Childhood Autism Rating Scale, 2nd Edition): Scores ≥ 30 indicate Autism Spectrum Disorder.
SCQ (Social Communication Questionnaire): Scores ≥≥ 15 indicate a high risk for Autism Spectrum Disorder.
CIBT (Child Interactive Behavior Test): T-score interpretation - High (≥ 60), Average (40-59), Low (30-39), Very low (≤ 29)