What is a Pervasive Developmental Disorder (PDD)?
There are many childhood disorders under the PDD umbrella. The most widely known PDD is Autism. Professionals and parents of children with PDD often describe individuals as being "on the spectrum" meaning that their behaviors fall on a continuum regarding the intensity of observed symptoms.
Individuals with PDD display significant deficits in three major areas: (1) social interaction, (2) communication, and (3) stereotyped and/or repetitive patterns of behavior and interests (i.e., hand flapping, lining up objects, inflexible adherence to nonfunctional routines, and preoccupation with parts of objects).
What tests are typically administered during the testing portion of the evaluation when there are concerns regarding a PDD?
Evaluations differ based upon the child's age and language skills. The essential components of the evaluation are as follows:
- A norm-referenced, standardized intelligence test is used though results may not be truly representative of the child because of the significant impact of language and behavioral difficulties. For individuals with limited language, the Wechsler tests are not appropriate. Therefore, measures such as the Stanford-Binet Fifth Edition or a nonverbal measure of intellectual functioning such as the Test of Nonverbal Intelligence-Third Edition is used.
- Based upon the child's current skill level, an appropriate measure of academic achievement is given to determine educational skills in reading, writing, mathematics, and language skills.
- A norm-referenced, standardized measure of adaptive behavior such as the Vineland Adaptive Behavior Scales-II (Survey Interview) or the Scales of Independent Behavior-Revised (SIB-R) is used. Measures of adaptive behavior focus on what an individual actually does on a day-to-day basis. Skills of personal and social self-sufficiency are assessed. Importantly, the purpose of the adaptive behavior measure is to focus on what an individual routinely does, not what he/she is capable of doing. A parent or primary caregiver would complete the adaptive behavior measure with Dr. Dub during an initial parent meeting.
- Additional measures such as the Childhood Autism Rating Scale, the Gilliam Autism Rating Scale-Second Edition, and the Gilliam Asperger's Rating Scale are used depending upon the suspected diagnosis.