Autism spectrum disorder diagnoses in toddlers have been established as accurate and stable across time in high-risk siblings and clinic-referred samples. Few studies have investigated diagnostic stability in children prospective identified in community-based settings. Furthermore, there is a dearth of evidence on the individual behaviours that…

The First Year Inventory is a parent-report measure designed to identify 12-month-old infants at risk for autism spectrum disorder. First Year Inventory taps behaviors that indicate risk in the developmental domains of sensory--regulatory and social--communication functioning. This longitudinal study is a follow-up of 699 children at 3 years of…

Objective: Our objective was to follow toddlers referred for risk of autism, using standardized observational measures administered frequently from age 18 months to age 36 months. Method: Sixty-five children who were consecutive referrals and 13 children from other research projects were seen approximately every 2 months, from age 18 months to age…