Autism spectrum disorder: screening, diagnosis, and medical evaluation.

Autism spectrum disorder (ASD) are a group of behaviorally defined neurodevelopmental disabilities with core deficits in socialization, communication, and behavior, although the presentation can be extremely variable. This article describes the core deficits in ASD, as well as the differential diagnosis and the more commonly associated comorbid disorders. The importance of early diagnosis is emphasized, and screening and assessment tools are reviewed. Finally, the role of the pediatric neurologist is discussed with regard to specific components of the evaluation, including history, physical examination, and ancillary testing.