Autism Assessment for School-Age Children vs Toddlers in Ontario

Early autism assessment in Ontario typically involves a developmental pediatrician or psychologist using the ADOS-2 Toddler Module, parent interview (ADI-R or clinical interview), and developmental history review. The assessment focuses on social communication milestones, play skills, and early signs of restricted/repetitive behaviour. Young children are assessed in play-based settings designed to elicit social interactions.

Ontario's early diagnostic hubs aim to assess children as young as 18 months when concerns arise. The 18-month enhanced well-baby visit serves as an initial screening point. If the M-CHAT-R/F screen is positive, referral for full assessment should happen immediately. Early identification allows earlier access to intervention through OAP foundational and core clinical services.

School-age autism assessments are more comprehensive because children have more developmental history and the diagnostician must differentiate autism from other conditions (ADHD, anxiety, learning disabilities). Assessments typically include ADOS-2 Module 3, cognitive testing (WISC-V), adaptive behaviour assessment (Vineland-3), academic testing if learning concerns exist, and interviews with parents and teachers.

School-age children who were missed in early childhood may present with subtler social differences, compensatory strategies, or co-occurring conditions that complicate diagnosis. Girls and children with strong verbal abilities are particularly at risk for missed or delayed diagnosis at school age. Assessors should consider masking and look beyond surface-level social behaviour.