Comparison of gesture-vocal synchrony and gestures of two children aged 3 to 26 months with and without autism spectrum disorder.

The objective was to compare gesture-vocal synchrony in language functioning between mothers and babies and the gestural typology of babies from 3 to 26 months of age, one of them with autism spectrum disorder (case R), diagnosed at age 3, and the other without diagnosis (case B). It was select moments in which there was greater mother-baby interaction, from a bank of mother-baby interactions footage, from 3 to 26 months. It was analyzed using the Eudico Linguistic Annotator software ( ELAN), considering multimodal categories of sign language and speech of mothers and babies for descriptive statistical analysis. The results showed differences in the frequencies and types of gestures between the babies and also in the synchrony between them and their mothers. In the case of B., the gesture-vocal synchrony and variety of gestures is inserted in a context of conjunction between him and his mother in the first year of life, which gave rise to the second enunciative mechanism in the second year of life. In case R, the conjunction relationships were not established, as the difficulties in reading discomfort and annoyance gestures, very present in the baby since its first months of life, hindered the engagement and shared attention of the mother and her baby, disfavoring the inscription of gesture as language. R. showed language acquisition delay at 26 months. Although the gestural typology of B and R are similar, the frequencies, the quality and, above all, the gesture-vocal synchrony differ between dyads.