How is Autism Diagnosed?

Presently, there is no single medical test that will definitively diagnose autism. Autism is a complex disorder that requires comprehensive evaluation involving a multidisciplinary team. This team includes a psychologist, neurologist, psychiatrist, developmental pediatricians, school psychologist, speech therapists, and other professionals who diagnose children with Autism Spectrum Disorders(ASD). The team members will perform a thorough neurological assessment and in-depth cognitive and language testing.

Some of the testing and screenings that are often used in the diagnostic process are: Pervasive Developmental Disorders Screening Test -2, CARS (Childhood Autism Rating Scale), Autism Diagnostic Checklist Form E-2, CHAT (Checklist for Autism in Toddlers), M-CHAT (Modified Checklist for Autism in Toddlers), ADI-R (Autism Diagnostic Interview - Revised) and ADOS (Autism Diagnostic Observation Scale). The ADOS is considered the "gold standard" for assessing and diagnosing autism and pervasive developmental disorder (PDD) across ages, developmental levels, and language skills. In addition, parental interview based on their observations and medical history are taken into consideration.

There are a core group of behaviors that the team may use to alert them to the possibility of a diagnosis of autism. Those behaviors are:

• impaired ability to make friends with peers
• absence or impairment of imaginative and social play
• impaired ability to initiate or sustain a conversation with others
• stereotyped, repetitive, or unusual use of language
• restricted patterns of interest that are abnormal in intensity or focus
• inflexible adherence to specific routines or rituals

• preoccupation with certain objects or subjects

In addition, children who have hearing problems can have behaviors that could be mistaken for autism. Consequently, these children with delayed speech development should also have their hearing tested.

The criterion required to make a diagnosis of autism or a Pervasive Development Disorder (PDD) is the current version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). It has specific criterion that consist of five disorders under the PDD umbrella which include Autism, Aspergers, Rhett's Syndrome, Childhood Disintegrative Disorder, and PDD-NOS (not otherwise specified).

The diagnosis of autism may be made when a specified number of characteristics listed in the DSM-IV are present. There are six characteristics of ASDs used to qualify for a diagnosis; a person must have a total of six or more items from (1), (2), and (3), with at least two from (1) and one each from (2) and (3):

Lastly, once this thorough evaluation is completed, the team usually meets with parents or caregivers to explain the results of the evaluation and to present the diagnosis.