The relationship between pitch contours in infant-directed speech and early signs of autism in infancy.

Purpose: Mother-infant interactions during the first year of life are crucial to healthy infant development. The infant-directed speech (IDS), and specifically pitch contours, used by mothers during interactions are associated with infant language and social development. However, little research has examined pitch contours towards infants with socio-communication and language differences, such as those displaying early signs of autism spectrum disorder (autism). This study aimed to explore the association of infant autism signs and pitch contours used by mothers with their 12-month-old infants.

Method: Mother-infant dyads (n = 109) were recruited from the University of Newcastle BabyLab. Parent-infant dyads completed a 15-min interaction, from which a total of 36,128 pitch contours were measured and correlated with infant autism signs. Infant autism signs were assessed via parent-report (First Year Inventory; Reznick et al., 2007). A subset of high-risk infants (admitted to a neonatal intensive care unit, n = 29) also received an observation-based assessment (Autism Detection in Early Childhood; Young & Nah, 2016).

Results: Mothers used fewer sinusoidal contours when they rated their infant as displaying more autism signs (r = - .30, p = .004) and more autism-related sensory regulation issues (r = - .31, p = .001). Mothers used fewer flat contours if their infant displayed more researcher-rated autism signs (r = - .39, p = .04).

Conclusions: This study provides the early evidence that maternal pitch contours in IDS are related to early autism signs in infancy. If our findings are replicated in follow up studies where infants are followed to diagnosis, maternal IDS may be an important element of future early intervention protocols that focus on communication for infants with risk for autism.