An Introduction to Autism
According to NIMH, evidence over the last 15 years shows that intensive early intervention for at least two preschool years improves the outcome for most children diagnosed with ASD. To provide a diagnosis, specialists look for certain behavioral characteristics. The child must exhibit problems in at least one of the areas of communication, socialization, or restricted behavior before the age of 3.
Diagnosis of ASD is done in two stages. The first stage occurs during a routine checkup that includes a developmental screening test. If any possible indicators of ASD present themselves during this checkup, the pediatrician will request further testing by a team that includes a psychologist, neurologist, psychiatrist, and speech therapist. The specialists then perform neurological and genetics assessments, as well as cognitive and language testing. According to the Autism Genetic Resource Exchange (AGRE), testing may include the use of the Autism Diagnosis Interview Revised (ADI-R) and the Autism Diagnostic Observation Schedule (ADOS-G). The ADI-R consists of a structured interview, conducted with a caregiver, which contains over 100 items covering four main factors: the child's communication, social interaction, repetitive behaviors, and age of onset symptoms. The ADOS-G is an observational assessment that looks for communication behaviors that are usually absent, abnormal, or delayed in children with ASD.
NIMH describes another test, called the Childhood Autism Rating Scale (CARS), which evaluates the child's body movements, adaptation to change, listening response, verbal communication, and relationship to people. The child is then rated on a scale based on the typical behavior of children the same age. This test is mostly used with children over 2 years old.
Once these tests have been completed by the team of specialists, a diagnosis is usually reached and treatment options can be explored.