Autism Adversely Affects Toddlers’ Joint Engagement with Sounds, Especially Speech

Background: Research on joint attention in autism spectrum disorder (ASD) has focused almost exclusively on the sharing of tangible objects, leaving unclear whether ASD affects auditory joint engagement (AJE). Typically-developing (TD) toddlers often delight in sharing sounds with parents, creating opportunities for language learning. But toddlers with ASD may display atypical reactions to sound (e.g. ignoring their name) that might adversely affect communicating about and sharing sounds.

Objectives: Our aims were to discern whether AJE occurs less often for toddlers with ASD than for TD toddlers or toddlers with non-ASD developmental disorders (DD), and whether AJE to speech is more impacted than AJE to environmental sounds.

Methods: 141 toddlers (mean age=23 months)—46 ASD, 46 DD, and 49 TD—and their parents participated. AJE was observed during four auditory scenes, one for each of four types of sounds: music, animal, mechanical, and speech including child’s name. In each scene, the sound occurred twice while the child and parent played, first in a 30-sec ignore-sound phase, during which the parent ignored the sound, and then in a 60-sec share-sound phase, during which the parent tried to share the sound. Three concurrent video records (one from a headcam on the parent’s forehead) were reliably coded for the child’s initial reaction to sound (alerts, orients, sustained interest in phase 1), communication about sound (bids to share in phase 1; speaks, points in both phases); and AJE (total, coordinated, supported in phase 2).

Results: Parents almost always followed instructions, initially ignoring (94%) and then attempting to share the sound (91%). When parents followed instructions during the ignore-phase, most children alerted, oriented, and sustained interest (see Figure 1)—although in the speech scene children in the ASD group did so significantly less than others. In contrast, few children with ASD communicated about the sound (speaks, points, shares), differing strongly from the TD group for all sound types (odds ratios > 3.0). When parents followed instructions during the share-sound phase, again few children with ASD communicated about the sound, differing significantly from the TD group for all sound types. Total AJE and coordinated AJE were also less likely for children with ASD than TD children for all sound types, whereas supported AJE was less likely only for music scenes. ASD and TD groups differed pervasively, for 32 of 44 tests; DD differed from ASD for just 12 of those 32, 6 involving the speech scene.

Conclusions: This study provides an unprecedented view of how toddlers with ASD react to and share speech and environmental sounds during parent-child interactions. Like their peers with TD and DD, they often alerted and oriented to environmental sounds, but were less likely to react to speech or to communicate about, share interest in, or be jointly engaged with any of the sound types. Intriguingly, only supported AJE, when the child shares sound but does not explicitly attend to the parent, appeared spared. Implications for communication and language development and for early interventions seeking to enhance joint engagement are discussed.