20127
Joint Attention and Language Development in Infants at Risk for Autism
Few studies have prospectively examined joint attention and language development in infants with an older sibling with ASD (Sibs-ASD), who have a higher risk of ASD and/or language delay than infants with an older sibling without ASD (Sibs-TD; see Rogers, 2009). We hypothesized that Sibs-ASD would have lower RJA, receptive language, and expressive language scores than Sibs-TD. We also expected to replicate the findings of Hudry and colleagues (2013) that Sibs-ASD would have a smaller gap between receptive and expressive language scores than Sibs-TD. Moreover, we expected RJA at 9, 12, or 15 months of age would positively predict 24-month language scores across groups.
Objectives: This study examined associations between joint attention across 9, 12, and 15 months and multiple measures of language development across 9, 12, 15, 21, and 24 months in Sibs-TD versus Sibs-ASD.
Methods:
Twenty-one Sibs-TD (11 female; 10 male), 20 Sibs-ASD (10 female; 10 male), and their mothers participated as part of a larger longitudinal study of Sibs-ASD. The Early Social Communication Scales were administered to infants, and later coded for Initiating and Responding to Joint Attention (IJA and RJA; Mundy et al., 2003). We assessed infants’ receptive and expressive language using the MacArthur Communication Development Inventories (MCDI; Fenson et al., 1993), Vineland Adaptive Behavior Scales (Vineland-II, Sparrow et al., 2005), and the Bayley Scales of Infant Development (Bayley-III, 2006). See Table 1.
Results:
A one-way ANOVA between groups revealed that Sibs-ASD had significantly less growth in IJA from 9 to 15 months compared to the Sibs-TD (F(1, 30) = 10.107, p = .004). However, there were no significant differences in RJA scores between groups. Sibs-ASD had significantly lower receptive vocabulary at 15 months on the MCDI (F(1, 30) = 7.25, p = .011) and 21 months on the Vineland (F(1, 30) = 4.310, p = .047). Sibs-ASD also had significantly lower Bayley expressive language scores than Sibs-TD at 12 months (F(1, 30) = 4.079, p = .053). Also, the advantage of receptive over expressive language skills on the MCDI at 15 months was significantly lower in Sibs-ASD than Sibs-TD (F(1, 30) = 11.64, p = .002). Across groups, 15-month RJA was positively correlated with 15-month MCDI expressive (r = .476, p = .004) and 24-month MCDI expressive scores (r = .456, p= .022).
Conclusions:
These findings suggest that Sibs-ASD, as a broader group, may not exhibit joint attention deficits when compared to Sibs-TD at one time point. However, Sibs-ASD did exhibit less growth in IJA than Sibs-TD. Our results also indicated that Sibs-ASD appear to have (a) significantly lower receptive language abilities at 15 and 21 months and (b) a significantly lower receptive over expressive language advantage at 15 months compared to Sibs-TD. Across groups, RJA at 15 months predicted expressive language at 15 and 24 months. One key implication of this study is that given the link between early RJA and language development, facilitation of the early ability to respond to joint attention bids could mediate language deficits in Sibs-ASD.