Social Communication Deficits Are Measurable In Very Young Infants at Risk for ASD

Background:  The early identification of atypical development among very young infants at risk for a later diagnosis of autism (ASD) is important to facilitate the earliest possible implementation of early intervention.

Objectives:  To examine if there are measurable early differences in social communication at 3- and 6-months of age (mo) in infants who were later classified as either having or not having ASD (ASD+/ASD-) in toddlerhood using the Autism Diagnostic Observation Schedule-Toddler Module (ADOS-T).

Methods:  Forty infants (20 females) were enrolled in this study by age 2mo, including infant siblings of children with ASD, infants conceived through infertility treatments, and infants without either history; 58% were Caucasian, and 30% reported mixed ethnicity. At 3mo and 6mo, social communication skills were assessed using the Rossetti Infant-Toddler Language Scale (RITLS). At chronological and nonverbal mental ages of ≥ 12mo, based on the Mullen Scales of Early Learning (MSEL), and after having achieved independent ambulation, participants were administered the ADOS-T to obtain ASD classification.  There were no significant differences on the MSEL between the ASD+ and the ASD- groups (t(38)=1.04, p=.304).

Group differences in the subscale domains of the RITLS (Interaction-Attachment, Pragmatics, Play, Language Communication, and Language Expression) were examined using Mann-Whitney analyses; differences in individual subscale items were evaluated by Chi-Square analyses.

Results: Seventeen participants met classification for ASD and 23 did not based on the ADOS-T. Subscale and item analyses results are presented in the Table.

 

Rossetti Infant-Toddler Language Scale
	3mo	6mo
Subscale Analyses
Interaction/Attachment	NS	z= -2.87, p=.034
Pragmatics		z= -2.94, p=.003
Play		z= -1.45, p=.148
Language Comprehension		z= -2.92, p=.004
Language Expression		z= -3.31, p=.001
Item Analyses
Interaction/Attachment	shows differing responses to vocalizations (χ2(1)=6.01, p=.014)	smiles spontaneously to human contact (χ2(1)=4.39, p=.036) smiles when playing alone (χ2(1)=6.01, p=.014) stops crying when spoken to (χ2(1)=5.97, p=.015)
Pragmatics		imitates facial expressions (χ2(1)=5.63, p=.018)
Language Comprehension		stops crying when spoken to (χ2(1)=11.53, p=.001) discriminates between threatening and friendly voices (χ2(1)=7.41, p=.006)
Language Expression	vocalizes to caregiver’s smile (χ2(1)=4.39, p=.036) produces a hunger cry (χ2(1)=6.01, p=.014)  vocalizes to express pleasure (χ2(1)=4.39, p=.036)	vocalizes feelings through intonation (χ2(1)=6.01, p=.014) takes turns vocalizing (χ2(1)=11.47, p=.001) babbles (χ2(1)=6.81, p=.009) stops babbling when another person vocalizes (χ2(1)=3.88, p=.049)  initiates "talking" (χ2(1)=4.09, p=.043) demonstrates sound play when alone or with others (χ2(1)=7.73, p=.005) whines with a manipulative purpose (χ2(1)=4.18, p=.041)

Conclusions:  Early social communication deficits among infants later classified as ASD+ appear to be measurable as early as age 3mo using the Rossetti Infant-Toddler Language Scale, in particular skills in the Interaction/Attachment and Language Expression domains. Absence of any of these early social communication behaviors may be clinically significant “red flags” for heightened vigilance and monitoring of an infant’s development. Although requiring replication in larger samples, these findings may ultimately prove helpful in developmental surveillance efforts in clinical settings as part of a screening instrument for very young infants.



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