It is often difficult to make a definitive diagnosis prior to age 2 or 3; however, recent research has begun identifying predictive behaviors in children as young as 12 months. Parents are usually the first to notice unusual behaviors. A parent with concerns about their child’s development should ask the child’s doctor about autism screening or request a referral for a developmental evaluation.

A medical evaluation of autism may be made by a physician or psychologist with expertise in diagnosing ASD. The evaluation may include:

• Detailed history, physical and neurologic exam
• Careful observation of the child at play and interaction with the caregiver
• Standardized autism rating scale or observation schedule
• Hearing test
• Language evaluation
• Cognitive testing
• Laboratory tests such as chromosomes, Fragile X, microarray
• Neurologic tests such as the EEG or MRI