To assess whether taking into account interaction synchrony would help to better differentiate autism (AD) from intellectual disability (ID) and typical development (TD) in family home movies of infants aged less than 18 months, we used computational methods. First, we analyzed interactive sequences extracted from home movies of children with AD (N = 15), ID (N = 12), or TD (N = 15) through the Infant and Caregiver Behavior Scale (ICBS). Second, discrete behaviors between baby (BB) and Care Giver (CG) co-occurring in less than 3 seconds were selected as single interactive patterns (or dyadic events) for analysis of the two directions of interaction (CG→BB and BB→CG) by group and semester. To do so, we used a Markov assumption, a Generalized Linear Mixed Model, and non negative matrix factorization. Compared to TD children, BBs with AD exhibit a growing deviant development of interactive patterns whereas those with ID rather show an initial delay of development. Parents of AD and ID do not differ very much from parents of TD when responding to their child. However, when initiating interaction, parents use more touching and regulation up behaviors as early as the first semester. When studying interactive patterns, deviant autistic behaviors appear before 18 months. Parents seem to feel the lack of interactive initiative and responsiveness of their babies and try to increasingly supply soliciting behaviors. Thus we stress that credence should be given to parents' intuition as they recognize, long before diagnosis, the pathological process through the interactive pattern with their child.

Autism spectrum disorders (ASD) are thought to be present right from birth, even if a minority of children displays a normal course during infancy followed by a regression during the second year of life. However, established criteria are not yet available to differentiate these different courses of ASD, and data coming from different sources have not yet been organized into a clear definition. The aim of this study was to elucidate the time of onset, as well as type, frequency and stability of symptoms during the first year of life in ASD. The behavioral summarized evaluation scale, applied to 40 home movies of children later diagnosed as having ASD, showed that most of the subjects (87.5%) display symptoms within the first year of life, when only a small group (12.5%) is completely symptom free. A group of more rated symptoms was found, constituting a typical pattern characterized by being withdrawn, and displaying poor social initiative, hypoactivity, and lack of emotional modulation. The importance of these findings is discussed in relation to early diagnosis and treatment.

Objective: The main aim of the research is to study the early behavioral development in autistic children through home movies. Methods: fifteen home movies, regarding the first 2 years of life of autistic children are compared with the home movies of 15 normal children. The films of the two groups were mixed and rated by blind ratings with the Grid for the Assessment of Normal Behavior in Infants and Toddlers. The grid is composed of 17 items grouped into three developmental areas: social competence, intersubjectivity and symbolic activity. For every area, we have identified specific children’s behaviors. Results: Significant differences between the two groups are found both in the range of age 0–6 for intersubjectivity, and in the ranges of age 6–12 and 18–24 for symbolic activity. Conclusions: The authors pose some hypotheses about an early-appearing impairment of intersubjectivity, the ability to represent other’s state of mind, in subjects with autistic disorder.