TY - CHAP M1 - Book, Section TI - Chapter 27. Autism A1 - Frye, Richard E. A2 - Carney, Paul R. A2 - Geyer, James D. Y1 - 2010 N1 - T2 - Pediatric Practice: Neurology AB - Autism spectrum disorder (ASD) is a behaviorally defined neurologically-based developmental disorder with an onset before 3 years of age. ASD encompasses three diagnoses: autism, Asperger disorder (AD), and pervasive developmental disorders not otherwise specified (PDD-NOS). Autism is defined by abnormal development and/or regression in social interaction and communication along with repetitive and stereotyped interests and behaviors.1 Although the DSM-IV-TR also lists disintegrative and Rett disorder as subtypes of ASD, the former is rarely diagnosed and the latter is recognized as a distinct neurodegenerative disorder. Diagnosis of autism is usually made around the age of 18 to 24 months, although, upon reflection, parents typically report concerns in the first year of life. This gap between parents' early concerns and the relatively late diagnosis, along with the importance of early intervention, highlights the necessity to find reliable tools for early diagnosis. Recent studies have suggested that symptoms of autism may be detectable as early as 14 months of age using standardized assessments.2 ASD associated with developmental regression accounts for approximately one-third of the cases and usually occurs between the first and second years of life. Late-onset developmental regression, particularly after 3 years of age, highly suggests an underlying neurological disorder. SN - PB - The McGraw-Hill Companies CY - New York, NY Y2 - 2024/03/29 UR - accesspediatrics.mhmedical.com/content.aspx?aid=6654714 ER -