Early Attentional Abilities Are Stable In Infant Siblings of Children with An Autism Spectrum Disorder (ASD)

Background:

In the first year of life there are rapid changes in the development of attention. Both dyadic and triadic attention have been examined as early markers of Autism Spectrum Disorder (ASD) in the at-risk infant siblings of children with an ASD (ASD-sibs). Studies comparing ASD-sibs and infant siblings of typically developing children (COMP-sibs) have, however, yielded conflicting results. This study examined dyadic and triadic attention between six and nine months in ASD-sibs and COMP-sibs to identify the stability of these skills in each group. This information paves the way for understanding future development in these infants.

Objectives:

To compare: 1) the stability of early dyadic attention, 2) the stability of triadic attention, and 3) mean group differences in these abilities among ASD-Sibs and COMP-Sibs.

Methods:

Seventeen ASD-sibs and twenty COMP-sibs participated at six and nine months. Dyadic attention was measured in the Face to Face-Still-Face Protocol (FFSF) at six and nine months. In the FFSF, parents were instructed to play normally with their infant, hold a still-face, and then resume play. Dyadic attention was indexed as the rate per minute of infants’ gaze shifts at and away from the parent’s face. Triadic attention was measured in the Early Social Communication Scales (ESCS) at six and nine months. In the ESCS, an examiner plays with the infant in a semi-structured interaction. Triadic attention was measured as the rate per minute of infants’ initiating joint attention bids.

Results:

Among ASD-sibs, there was a significant association between rates of gaze shifts at six and nine months, r= .65, p= .02; this association was not significant for COMP-sibs, r=.15, p= .57. Among ASD-sibs, there was also a significant association between rates of initiating joint attention at six and nine months, r= .51, p= .04; again, this association was not significant for COMP-sibs, r= .28, p= .24. There were no group differences on either measure at either age.

Conclusions:

Among ASD-sibs, both rate of gaze shifting toward and away from the parent’s face and rate of initiating joint attention with an examiner were stable across a three-month period; neither behavior showed stability among COMP-sibs. While ASD-sibs and COMP-sibs did not differ on mean levels of dyadic and triadic attention, only ASD-sibs exhibited significant stability. The lack of significant stability demonstrated by COMP-sibs may reflect dynamic development, characterized by transformation and reorganization. Conversely, ASD-sibs at the same chronological age may be undergoing static development, characterized by continuity and stability. This suggests a endophenotype that tethers attentional behaviors and limits the range of developmental pathways available to at-risk infants in both dyadic and triadic contexts. The current findings have important implications for those ASD-sibs who have lower levels of dyadic or triadic attention at six months because they continue to show lower levels of these abilities at nine months. We will continue to examine the stability of dyadic and triadic attention at later ages to further explore this hypothesis.