RESUMEN
Initiation of joint attention is a critical developmental function related to further social communicative development in infancy. Joint attention appears to be impaired very early in life for children with autism spectrum disorder (ASD), well before a formal diagnosis is established. To observe the early development of joint attention, we prospectively followed infant siblings at high risk for ASD (HR) and low-risk (LR) infants. Initiations of joint attention behaviors were coded with respect to frequency, quality, and variety from videos taken during the administration of the Autism Observation Schedule for Infants. Participants were further stratified based on the presence of ASD (n = 17) or language delay (n = 19) at 3 years of age. Our results revealed that initiations of joint attention are impaired from 12 months of age in both children with ASD and those with language delay, especially for use of gestures (i.e., showing and pointing). At 18 months, fewer initiations of joint attention in all three dimensions distinguished infants with ASD, compared to infants with language delay and HR and LR infants without a diagnosis. Beyond the definition of initiation of joint attention as an early sign for ASD, clinical implications of these results concern the importance of intervening on frequency, quality, and variety of joint attention as early as possible in infants at heightened risk for ASD.
