Formal Screening Tools
A variety of tests and questionnaires help parents and doctors measure autism symptoms so as to determine if symptoms of autism or other PDDs are present. The most commonly used screening tests for autism and related pervasive developmental disorders are the Checklist for Autism in Toddlers (CHAT) and the Childhood Autism Rating Scale (CARS). These screening tests are described below along with other tests commonly used to detect autism. These formal tests are frequently administered at the end of an initial autism examination (usually lasting at least 45 minutes) given by a professional clinician. Pre-screening and parent-administered tests may be given prior to formalized, clinician-administered tests like CHAT and CARS.
A great number of tests have been created to assist parents and interested adults in quickly identifying whether their children are potentially autistic or PDD or not. Such tests serve a screening or triage function; they are simple to administer (usually consisting of questions to be answered yes or no) and yield simple scores that can be interpreted with cutoff-points suggesting whether everything is okay, or whether a problem may be present. They are not designed to suggest diagnoses.
Pervasive Developmental Disorders Screening Tests (I and II). Like the M-CHAT (described below), the Pervasive Developmental Disorders Screening Test I is a questionnaire examining pervasive developmental disorder symptoms which has been specifically designed for parents to fill out on their own. It is appropriate to administer the test when the child is between the ages of eighteen months and three years. The test contains seventy-one items that cover symptoms commonly reported by parents of children who have autism spectrum diagnoses. Parents complete three sections covering the three deficit areas common to autism: communication, social interactions and stereotyped movements. Their responses determine if their child should receive further evaluation.
The Pervasive Developmental Disorders Screening Test II is like Test I in that it is a questionnaire designed to allow parents to self-rate their child's PDD-like behaviors. This test differs from Test I in that it divides questions into three groups: caretakers' screening exam for ages twelve to eighteen months, developmental clinic screening from birth to eighteen months and autism severity clinic screener from birth to eighteen months.
More information about the PDDST is available here. http://www.innovact.co.za/Pervasive%20Developmental%20Disorders%20Screening%20Test-II%20(PDDST-I.htm
- The Ages and Stages Questionnaire. The Ages and Stages Questionnaire is another PDD screening test. It is unique in that it has nineteen variations which are selected according to the subject child's age. The variations cover ages between four and sixty months old. This test focus on communication, motor skills, social skills and problem solving. Parents responses determine if their child should receive further evaluation. This questionnaire can be purchased through: http://agesandstages.com/
- The Child Development Inventories. The Child Development Inventories consist of three tests all of which are intended to be completed by parents. The first is a screening questionnaire for parents that surveys PPD symptoms without regard to age appropriateness. The second, known as the Infant Developmental Inventory (IDI), is appropriate for administration to young children, eighteen months of age or less. The IDI measures important milestones by months as per normal development. Parents can use the IDI chart as a general guide for tracking their child's relative developmental progress. The third test in this series, called the Child Development Inventory, is appropriate for toddlers and preschoolers. An outline and samples of the tests can be found at: http://www.childdevrev.com
- Social Communication Questionnaire. The Social Communication Questionnaire, formerly known as the Autism Screening Questionnaire, contains forty items that are useful in identifying possible pervasive developmental disorders. This test focuses on social interaction and language development and is appropriate for most age groups. This test should be considered a screening test only; it assists in identifying PDD symptoms, but cannot reliably differentiate an autism diagnosis from other pervasive developmental disorders. The Social Communication Questionnaire can be found at: http://www4.parinc.com/Products/Product.aspx?ProductID=SCQ
- The Parents' Evaluation of Developmental Status. As its name suggests, The Parents' Evaluation of Development Status (PEDS) is designed to assist parents determine whether their children are developmentally delayed. It is appropriate for use with children under eight years old. The questionnaire contains only ten questions so it is completed very quickly. PEDS is usually administered before the CHAT and M-CHAT screening tests. More information about PEDS can be found at: http://www.pedstest.com/