30131
Coordination Is Key: Joint Attention and Vocalizations in Infant Siblings of Children with Autism Spectrum Disorder
Infants at heightened risk (HR) for autism spectrum disorder (ASD) and who later receive an ASD diagnosis exhibit delays in joint attention (JA), shared attention to objects with social partners, and pre-linguistic vocalization development (Goldberg et al., 2005; Paul et al., 2011). Vocalizations develop concurrently with JA and are used to engage caregivers (Wu & Gros-Louis, 2014). Previous studies have focused on JA and vocalization development separately; the coordination of these behaviors as well as their frequency remains to be explored.
Objectives:
To examine JA (e.g., gaze shifts, gestures), vocalizations, and their coordination in infants with older siblings with ASD.
Methods:
In a prospective longitudinal study, 50 (30 Male) HR infants were observed at 14, 18 and 24 months during the Early Social Communication Scales (ESCS; Mundy et. al., 2003), a semi-structured task designed to elicit JA behaviors. At 36 months, infants were classified into one of three outcome groups: Autism Spectrum Disorder (ASD; n=9), Language Delay without ASD (LD; n=15) or No Diagnosis (ND; n=25). ESCS sessions were videotaped and coded offline by naive coders for initiating joint attention (IJA: e.g., gaze shifts, showing) and initiating behavioral requests (IBR: e.g., reaching, pointing, giving) according to the ESCS manual (Mundy et. al., 2003). Each vocalization was identified and coded as vowel only (VO), syllabic (i.e. containing a consonant), or word. Coordination of these behaviors was identified any time a vocalization overlapped with a JA behavior.
Results:
Repeated measures ANOVAs were conducted for all analyses. Examining JA, a significant main effect of outcome was found only for higher level IJA behaviors F(2,47) = 14.430, p<.001, η2p = 0.38, no main effects or interaction were found for production of low IJA, high IBR or low IBR. For vocalizations, a 3 (vocalization type) x 3 (age) x 3 (outcome) repeated measures ANOVA revealed a significant 3-way interaction F(8, 188) =8.613, p <.001, η2p= 0.27. Follow-up ANOVAs indicated a significant interaction between age and vocalization type for ND F(4, 100) =71.71, p <.001, η2p= 0.74 and LD F(4, 56) =10.61, p < .001, η2p= 0.43 infants, but not ASD infants F(4, 32) =.657, p =0.63, η2p= 0.08 (see Figure 1). Infants later diagnosed with ASD consistently produced fewer vocalizations of all three types and had no age-related changes. Finally, examining the coordination of JA and vocalizations, a main effect of outcome for IJA + vocalizations and IBR + vocalizations was found. Infants who later received an ASD diagnosis coordinated JA and vocalizations less frequently than their ND and LD peers (see Figure 2).
Conclusions:
HR infants who later receive an ASD diagnosis produced fewer higher level IJA behaviors, fewer vocalizations, and more vowel only vocalizations across all three-time points. Additionally, these infants had specific difficulty in coordinating these behaviors. These differences in the coordination of early communicative behaviors may have cascading effects on social and language development in infants who later receive an ASD diagnosis as coordination of JA and vocalizations likely enhances communicative quality and engagement with others.