Sensitivity to temporal synchrony and selective attention in audiovisual speech in infants at elevated likelihood for autism: A preliminary longitudinal study.

Researchers studied how babies look at faces when people talk, comparing babies with autistic siblings to other babies. Both groups could tell when lip movements didn't match speech sounds by 12 months. However, babies with autistic siblings looked less at speakers' mouths at 12 months and didn't show the usual increase in mouth-looking that helps language development. This suggests early differences in how at-risk babies process speech.

This longitudinal eye-tracking study examined temporal synchrony detection and selective attention to mouths during audiovisual speech in 29 infants at 4, 8, and 12 months. Researchers compared infants at elevated likelihood for autism (having autistic siblings) with low-likelihood peers. Both groups detected temporal asynchronies in talking faces by 12 months. However, infants at elevated autism likelihood showed reduced attention to speakers' mouths at 12 months and no developmental changes in mouth-looking across the first year, unlike their typically developing peers who showed increasing mouth attention over time.

These findings suggest potentially atypical early mechanisms that support language acquisition in at-risk infants.

Findings suggest early differences in attention to speech-relevant facial features in at-risk infants. Reduced mouth-looking may serve as an early biomarker for language difficulties. Results support the importance of monitoring visual attention patterns in infant siblings of autistic children.

Small sample size (n=29) and preliminary nature limit generalizability. Study design unclear from abstract. No information on diagnostic outcomes or follow-up beyond 12 months. Potential confounding factors not discussed.

Autism Spectrum Disorder is a highly heritable condition characterized by sociocommunicative difficulties, frequently entailing language atypicalities that extend to infants with a familial history of autism. The developmental mechanisms underlying these difficulties remain unknown. Detecting temporal synchrony between the lip movements and the auditory speech of a talking face and selectively attending to the mouth support typical early language acquisition. This preliminary eye-tracking study investigated whether these two fundamental mechanisms atypically function in infant siblings.

We longitudinally tracked the trajectories of infants at elevated and low-likelihood for autism in these two abilities at 4, 8, and 12 months (n = 29). We presented two talking faces (synchronous and asynchronous) while recording infants' gaze to the talker's eyes and mouth. We found that infants detected temporal asynchronies in talking faces at 12 months regardless of group. However, compared to their typically developing peers, infants with an elevated likelihood of autism showed reduced attention to the mouth at the end of the first year and no variations in their interest to this area across time.

Our findings provide preliminary evidence on a potentially atypical trajectory of reduced mouth-looking in audiovisual speech during the first year in infant siblings, with potential cascading consequences for language development, thus contributing to domain-general accounts of emerging autism.