| This retrospective study investigated the early emergence of social-emotional and communication markers associated with autistic spectrum disorders (ASD) in the framework of infant-caregiver interactions as they occurred on home videos, filmed from birth to 13 months of age. The onset of "cooing," reduplicative babbling, variegated babbling, first words, social smiling, as well as pointing was observed in a sample of typically developing infants and infants later diagnosed with ASD. The onset of these behaviours occurred significantly earlier in the typically developing group. In fact variegated babbling, first words, and pointing were not evidenced by infants with ASD in the first 13 months of life.;Differences in infant communication were also examined. Results indicated that between 6 weeks and 4 months of age there were no significant differences between the groups with respect to the coordination of eye contact and vocalizations. However, there were significant differences when coordinating eye contact with (1) nonverbal behaviours and (2) vocalizations and nonverbal behaviours, whereby infants with ASD showed a significantly lower proportion of both forms of cross-modal communication. Between 4 to 8 months of age there was not a significant difference between the groups in relation to coordination of eye contact and nonverbal behaviours. However, there were significant differences in coordination of eye contact with (1) vocalizations and (2) vocalizations and nonverbal behaviours, whereby infants with ASD showed a significantly lower proportion of both forms of cross-modal communication. The ASD group displayed a significantly higher frequency of eye contact as an independent response at the first age point and a significantly lower frequency at the second age point. Total communication scores were higher for the typically developing group as were the frequency of initiations towards the caregiver at both age points. In fact, initiations were not evidenced by the ASD group. These findings suggest that the onset of significant social-emotional and communicative milestones is delayed in infants with ASD. In relation to dyadic communication, the findings suggest that infants with ASD are less likely to implement cross-modal communication but may rely on uni-modal communication such as gaze very early on. |
