Pervasive developmental disorders

Autism is a neurodevelopmental disorder characterized by core impairments in social interaction and communication, and the presence of repetitive behaviors and restricted interests. Autistic Disorder, Asperger's Disorder, and PDD-NOS are now more commonly seen as a spectrum of disorders, which vary in the severity of social/communication difficulties and language outcome. Diagnostic accuracy has been an important area of investigation for autism researchers for a number of years. Diagnostic precision is critical for research aimed at uncovering the underlying biological causes; however, the heterogeneity and overlap of the behavioral phenotype make characterization within the autism spectrum difficult. The development of diagnostic assessments has been particularly helpful, in that diagnostic precision is important for epidemiological studies, various areas of research, and the determination of appropriate services and placements. Diagnostic assessment typically includes interviews with parent or other caregiver, a medical evaluation, direct behavioral observation, cognitive assessment, and assessment of adaptive behavior. Ongoing research continues to improve the ability to diagnose these disorders accurately and at a younger age, which is essential, given the importance of early screening and early intervention. © 2006