Imitation of Maternal Social Communication From 6 to 18 Months In Infants at Risk for Autism

Background: Impairments in language and social communication skills identified by 12 months of age in infants later diagnosed with autism include impairments in language, joint attention, imitation, and gesture production.  These findings come primarily from two lines of research: one examining early development retrospectively, from family home movies, after a diagnosis of autism has already been made; the other from studies of high-risk infants (HRA) who are followed prospectively. Recent investigations have also identified language delays in HRA infants who do not go on to receive ASD diagnoses. Given the pervasiveness of these language difficulties within the entire group of HRA siblings, a more detailed understanding of the factors that contribute to early language ability in this group of infants will potentially impact treatment not only for the subset who are diagnosed with ASD, but for a significant portion of siblings whose diagnostic status may be less clear. The current study unites the benefits provided by standardized laboratory measures with the more naturalistic setting of the home, by collecting prospective videos of semistructured infant-caregiver interactions. In doing so, we are able to examine the development of early social communication within the daily, reciprocal exchanges that occur between infants and their caregivers.

Objectives: The goal of the present study is to examine the trajectory of infant imitation of social communicative behaviors from 6 to 18 months and their relation to language ability at 18 months of age in a sample of infants at risk for autism.

Methods: Data for this project was obtained from a larger ongoing longitudinal study of infants at high risk for autism (HRA) and low risk controls (LRC). Upon enrollment, parents were provided with a video camera and a brief set of instructions for filming semistructured social interactions with their infants at home, twice per month. Activities include an object exploration task, in which infants are provided with a series of toy and ‘non-toy’ objects to play with, a book reading task, and several more open-ended social games or interactions (e.g. peekaboo, singing ‘itsy bitsy spider’). Videos were coded for infant imitation of maternal vocalization, gesture, and actions and further specified by the types of imitation within each of these categories (e.g. imitates point, imitates wave, imitates shaking rattle).

Results: Home video diaries have been collected from 104 families (59 HRA, 45 LRC). Of these, 88 infants have completed their 18-month laboratory visit, which includes administration of the Autism Diagnostic Observation Schedule (ADOS). Although final group status will be determined by scores at 36 months of age, 9 children have met diagnostic criteria at 18 months and are considered to have ASD for these analyses. Results of specific behavioral trajectories (rate of gesture imitation) will be discussed.

Conclusions: The current methodology allows for a more thorough understanding of the relationship between early social communicative skills, such as imitation of caregiver vocalizations, and later language abilities. These findings will have significant clinical implications by helping parents to ‘make the most’ of these early interactions.