Background The ability to spontaneously attend to the social overtures and activities of others is essential for the development of social cognition and communication. This ability is critically impaired in toddlers with autism spectrum disorders (ASD); however, it is not clear if prodromal symptoms in this area are already present in the first year of life of those affected by the disorder. Methods To examine whether 6-month-old infants later diagnosed with ASD exhibit atypical spontaneous social monitoring skills, visual responses of 67 infants at high-risk (HR) and 50 at low-risk (LR) for ASD were studied using an eye-tracking task. Based on their clinical presentation in the 3rd year, infants were divided into those with ASD, those exhibiting atypical development (HR-ATYP), and those developing typically (HR-TYP, LR-TYP). Results Compared to the control groups, 6-month-old infants later diagnosed with ASD attended less to the social scene, and, when they did look at the scene, they spent less time monitoring the actress in general and her face in particular. Limited attention to the actress and her activities was not accompanied by enhanced attention to objects. Conclusions Prodromal symptoms of ASD at six months include a diminished ability to attend spontaneously to people and their activities. A limited attentional bias towards people early in development is likely to have a detrimental impact on the specialization of social brain networks and the emergence of social interaction patterns. Further investigation into its underlying mechanisms and role in psychopathology of ASD in the first year is warranted.

Background In typical development, the unfolding of social and communicative skills hinges upon the ability to allocate and sustain attention towards people, a skill present moments after birth. Deficits in social attention have been well documented in autism, though the underlying mechanisms are poorly understood. Methods In order to parse the factors that are responsible for limited social attention in toddlers with autism, we manipulated the context in which a person appeared in their visual field with regard to the presence of salient social (child-directed speech and eye contact) and nonsocial (distractor toys) cues for attention. Participants included 13- to 25-month-old toddlers with autism (AUT; n=54), developmental delay (DD; n=22), and typical development (TD; n=48). Their visual responses were recorded with an eye-tracker. Results In conditions devoid of eye contact and speech, the distribution of attention between key features of the social scene in toddlers with autism was comparable to that in DD and TD controls. However, when explicit dyadic cues were introduced, toddlers with autism showed decreased attention to the entire scene and, when they looked at the scene, they spent less time looking at the speaker’s face and monitoring her lip movements than the control groups. In toddlers with autism, decreased time spent exploring the entire scene was associated with increased symptom severity and lower nonverbal functioning; atypical language profiles were associated with decreased monitoring of the speaker’s face and her mouth. Conclusions While in certain contexts toddlers with autism attend to people and objects in a typical manner, they show decreased attentional response to dyadic cues for attention. Given that mechanisms supporting responsivity to dyadic cues are present shortly after birth and are highly consequential for development of social cognition and communication, these findings have important implications for the understanding of the underlying mechanisms of limited social monitoring and identifying pivotal targets for treatment.

Background The diagnosis of autism spectrum disorder (ASD) made before age 3 has been found to be remarkably stable in clinic- and community-ascertained samples. The stability of an ASD diagnosis in prospectively ascertained samples of infants at risk for ASD due to familial factors has not yet been studied, however. The American Academy of Pediatrics recommends intensive surveillance and screening for this high-risk group, which may afford earlier identification. Therefore, it is critical to understand the stability of an ASD diagnosis made before age 3 in young children at familial risk. Methods Data were pooled across 7 sites of the Baby Siblings Research Consortium. Evaluations of 418 later-born siblings of children with ASD were conducted at 18, 24, and 36 months of age and a clinical diagnosis of ASD or Not ASD was made at each age. Results The stability of an ASD diagnosis at 18 months was 93% and at 24 months was 82%. There were relatively few children diagnosed with ASD at 18 or 24 months whose diagnosis was not confirmed at 36 months. There were, however, many children with ASD outcomes at 36 months who had not yet been diagnosed at 18 months (63%) or 24 months (41%). Conclusions The stability of an ASD diagnosis in this familial-risk sample was high at both 18 and 24 months of age and comparable with previous data from clinic- and community-ascertained samples. However, almost half of children with ASD outcomes were not identified as being on the spectrum at 24 months and did not receive an ASD diagnosis until 36 months. Thus, longitudinal follow-up is critical for children with early signs of social-communication difficulties, even if they do not meet diagnostic criteria at initial assessment. A public health implication of these data is that screening for ASD may need to be repeated multiple times in the first years of life. These data also suggest that there is a period of early development in which ASD features unfold and emerge but have not yet reached levels supportive of a diagnosis.

This prospective study examined object exploration behavior in 66 12-month-old infants, of whom nine were subsequently diagnosed with an autism spectrum disorder. Previous investigations differ on when the repetitive behaviors characteristic of autism are first present in early development. A task was developed that afforded specific opportunities for a range of repetitive uses of objects and was coded blind to outcome status. The autism/ASD outcome group displayed significantly more spinning, rotating, and unusual visual exploration of objects than two comparison groups. The average unusual visual exploration score of the autism/ASD group was over four standard deviations above the mean of the group with no concerns at outcome. Repetitive behaviors at 12 months were significantly related to cognitive and symptomatic status at 36 month outcome. These results suggest that repetitive or stereotyped behaviors may be present earlier than initially thought in very young children developing the autism phenotype.

Gross motor development (supine, prone, rolling, sitting, crawling, walking) and movement abnormalities were examined in the home videos of infants later diagnosed with autism (regression and no regression subgroups), developmental delays (DD), or typical development. Group differences in maturity were found for walking, prone, and supine, with the DD and © Springer Scicnce+Business Media, LLC 2007 Correspondence to: Sally Ozonoff, sjo7.onoff@ucdavis.edu. HHS Public Access Author Manuscript Author ManuscriptAuthor Manuscript Author ManuscriptAutism-No Regression groups both showing later developing motor maturity than typical children. The only statistically significant differences in movement abnormalities were in the DD group; the two autism groups did not differ from the typical group in rates of movement abnormalities or lack of protective responses. These findings do not replicate previous investigations suggesting that early motor abnormalities seen on home video can assist in early identification of autism.