Autism varies widely in its severity and symptoms and may go unrecognized, especially in mildly affected children or when it is masked by more debilitating handicaps. Doctors rely on a core group of behaviors to alert them to the possibility of a diagnosis of autism.  These behaviors are:

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• impaired ability to make friends with peers

• impaired ability to initiate or sustain a conversation with others

• absence or impairment of imaginative and social play

• stereotyped, repetitive, or unusual use of language

• restricted patterns of interest that are abnormal in intensity or focus

• preoccupation with certain objects or subjects

• inflexible adherence to specific routines or rituals

 

Doctors will often use a questionnaire or other screening instrument to gather information about a child’s development and behavior. Some screening instruments rely solely on parent observations; others rely on a combination of parent and doctor observations. If screening instruments indicate the possibility of autism, doctors will ask for a more comprehensive evaluation. Since autism is a complex disorder, a comprehensive evaluation requires a multidisciplinary team including a psychologist, neurologist, psychiatrist, speech therapist, and other professionals who diagnose children with ASD. The team members will conduct a thorough neurological assessment and in-depth cognitive and language testing.  Because hearing problems can cause behaviors that could be mistaken for autism, children with delayed speech development should also have their hearing tested. After a thorough evaluation, the team usually meets with parents to explain the results of the evaluation and present the diagnosis.

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Children with some symptoms of autism, but not enough to be diagnosed with classical autism, are often diagnosed with PDD-NOS. Children with autistic behaviors but well-developed language skills are often diagnosed with Asperger syndrome. Children who develop normally and then suddenly deteriorate between the ages of 3 to 10 years and show marked autistic behaviors may be diagnosed with childhood disintegrative disorder.  Girls with autistic symptoms may be suffering from Rett syndrome, a sex-linked genetic disorder characterized by social withdrawal, regressed language skills, and hand wringing.