Autism/Pervasive Developmental Disorder (PDD) is a neurological disorder that affects a child’s ability to communicate, understand language, play, and relate to others. PDD represents a distinct category of developmental disabilities that share many of the same characteristics.
The different diagnostic terms that fall within the broad meaning of PDD, include:
• Autistic Disorder,
• Asperger’s Disorder,
• Rett’s Disorder,
• Childhood Disintegrative Disorder, and
• Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS).
While there are subtle differences and degrees of severity among these conditions, treatment and educational needs can be very similar for all of them.
In the diagnostic manual used to classify mental disorders, the DSM-IV-TR (American Psychiatric Association, 2000), “Autistic Disorder” is listed under the heading of “Pervasive Developmental Disorders.” A diagnosis of autistic disorder is made when an individual displays 6 or more of 12 symptoms across three major areas: (a) social interaction, (b) communication, and (c) behavior. When children display similar behaviors but do not meet the specific criteria for autistic disorder (or the other disorders listed above), they may receive a diagnosis of Pervasive Developmental Disorder Not Otherwise Specified, or PDD-NOS.
Autism is one of the disabilities specifically defined in the Individuals with Disabilities Education Act (IDEA), the federal legislation under which infants, toddlers, children, and youth with disabilities receive early intervention, special education and related services. IDEA defines the disorder as “a developmental disability significantly affecting verbal and nonverbal communication and social interaction, generally evident before age 3, that adversely affects a child’s educational performance. Other characteristics often associated with autism are engagement in repetitive activities and stereotyped movements, resistance to environmental change or change in daily routines, and unusual responses to sensory experiences.” [See 34 Code of Federal Regulations §300.8(c)(1).]