500+ entries for parents and professionals.The only A-Z reference available on autism spectrum disorders and pervasive developmental disorders, this comprehensive encyclopedia includes more than 500 terms, alphabetically listed and clearly described. Today's most respected autism experts have contributed essential terminology from various disciplines -- including pediatrics, speech-language pathology, occupational therapy, physical therapy, education, psychology, and psychiatry -- to bring you reliable information on classification systems, signs and symptoms, causes, incidence and prevalence, diagnosis, screening and assessment, interventions, behavior, education, assistive technology, daily living, medical issues, and legislation.Synonyms and relevant cross-references are included for the terms, and the two appendixes describe assessment tools and instruments and list autism-related study centers and organizations. Every professional whose work involves autism spectrum disorders needs a copy of this essential reference -- to keep on hand for instant information and to share with parents of children who have these complex disorders.