Thursday, May 13, 2010

CDC Commentary: The Three Faces of Autism Spectrum Disorder -- Learn to Recognize Them

Marshalyn Yeargin-Allsopp, MD

Autism spectrum disorders or ASDs are a group of developmental disabilities that can cause significant social, communication, and behavioral challenges. People with ASDs share some similar symptoms, such as problems with social interaction. But there are differences in when the symptoms start, how severe they are, and the exact nature of the symptoms.
There are 3 different types of ASDs:
Autistic disorder also called "classic" autism. People with autistic disorder usually have significant language delays, social and communication challenges, and unusual behaviors and interests. Many people with autistic disorder also have intellectual disability.
The second type is Asperger syndrome. People with Asperger syndrome usually have some milder symptoms of autistic disorder. They might have social challenges and unusual behaviors and interests. However, they typically do not have delayed language or intellectual disability.
The third type is pervasive developmental disorder - not otherwise specified or PDD-NOS, also called "atypical autism". People who meet some of the criteria for autistic disorder or Asperger syndrome, but not all, may be diagnosed with PDD-NOS. People with PDD-NOS usually have fewer and milder symptoms than those with autistic disorder.
CDC's most recent data show that between 1 in 80 and 1 in 240 children with an average of 1 in 110 have an ASD. This is a prevalence of about 1%. It should also be noted that ASD prevalence was 4 to 5 times higher for boys than for girls. This study also showed there were concerns regarding development before the age of 24 months in the evaluation records of most children, but the average age of earliest ASD diagnosis was much later, at 54 months.
There are different methods to evaluate and diagnose autism. These include developmental screening and a comprehensive evaluation. Developmental screening is a short test to tell if children are learning basic skills when they should, or if they might have delays. During developmental screening the doctor might ask the parent to fill out a questionnaire on how their child learns, speaks, behaves, and moves. A delay in any of these areas could be a sign of a problem.
A comprehensive evaluation is a thorough review that may include looking at the child's behavior and development and interviewing the parents. It may also include a hearing and vision screening, genetic testing, neurological testing, and other medical testing. In some cases, the primary care doctor might choose to refer the child and family to a specialist for further assessment and diagnosis.
Specialists who can do this type of evaluation include:
  • Developmental pediatricians;
  • Child neurologists; and
  • Child psychologists or psychiatrists.
There are many tools to assess ASDs in young children, but no single tool should be used as the basis for diagnosis. Diagnostic tools usually rely on 2 main sources of information -- parents' or caregivers' descriptions of their child's development and a professional's observation of the child's behavior.
It is important to remember that studies consistently show that early identification and intervention can improve long-term outcomes for children.
For more information on autism spectrum disorders, please visit the Website listed on this page or visit Thank you.


Centers for Disease Control and Prevention. Autism Spectrum Disorders (ASDs). Available at: Accessed April 30, 2010.

Source: Medscape

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