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.

Objective The onset of autism is usually conceptualized as occurring in one of two patterns, an early onset and a regressive pattern. This study examined the number and shape of trajectories of symptom onset evident in coded home movies of children with autism and examined their correspondence with parent report of onset. Methods Four social-communicative behaviors were coded from the home video of children with autism (n = 52) or typical development (n = 23). All home video from 6 through 24 months of age was coded (3199 segments). Latent class modeling was used to characterize trajectories and determine the optimal number needed to describe the coded home video. These trajectories were then compared to parent report of onset patterns, as defined by the Autism Diagnostic Interview-Revised. Results A three trajectory model best fit the data from the participants with autism. One trajectory displayed low levels of social-communication across time. A second trajectory displayed high levels of social-communication early in life, followed by a significant decline over time. A third trajectory displayed initial levels of behavior that were similar to the typically developing group, but little progress in social-communication with age. There was poor correspondence between home video-based trajectories and parent report of onset. Conclusions More than two onset categories may be needed to describe the ways in which symptoms emerge in children with autism. There is low agreement between parent report and home video, suggesting that methods for improving parent report of early development must be developed.

Childhood disintegrative disorder (CDD) is a rare pervasive developmental disorder that involves regression after a period of at least 2 years of typical development. This case study presents data from family home movies, coded by reliable raters using an objective coding system, to examine the trajectory of development in one child with a reported regression at 48 months of age. Coding substantiated parent reports of mostly typical early development, followed by later catastrophic loss of skills across many developmental domains. Differential diagnosis of CDD and autism with regression is discussed.