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Autism Spectrum Disorders: Diagnosis

Diagnosing ASDs can be tricky since there’s no definitive test, like a blood test or an X-ray, that can indicate for certain that a child has one of these disorders. Instead, a doctor makes the diagnosis based on parents’ descriptions and observations of their child, as well as his clinical evaluations of a child’s behavior and development. “It’s a clinical judgment regarding where a child falls on the spectrum; it’s not clear-cut and that’s where there can be error in coming up with these diagnoses,” says M. Michelle Rowe, Ph.D., executive director of the Kinney Center for Autism Education and Support and Professor of health services at St. Joseph's University in Philadelphia.

Age of Diagnosis

If you have even the slightest suspicion that your child may have an ASD, share your concerns with your pediatrician right away. He or she may refer you to a specialist -- such as a developmental pediatrician, a child neurologist, a child psychologist or psychiatrist -- who can do a more in-depth evaluation of your child in order to make the correct diagnosis. You can also contact your state’s public early intervention system -- as a starting point, look up your state’s services at: www.nichcy.org/Pages/StateSpecificInfo.aspx -- to have your child evaluated to see if he qualifies for state-funded intervention such as speech therapy, occupational therapy or other services; you don’t need to wait for a physician’s diagnosis or referral.

Signs of ASDs can usually be seen in infants and toddlers, and early intervention therapies can make a big difference in a child's development. Unfortunately, the disorders can’t be reliably diagnosed until somewhere between 18 months and three years. And the reality is, it often happens later than that: after reviewing data from 13 sites participating in the CDC’s ongoing autism surveillance program, researchers at Washington University in St. Louis recently found that the median age of identification for children with ASDs is 5.7 years. The delay can mean that young children with an ASD might not get the beneficial therapies they need from an early age.

 

Diagnostic Criteria

To diagnose ASDs, physicians use criteria from the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders. Symptoms must be ongoing, not temporary, and severe enough to have a considerable impact on a child’s life and ability to function. Here’s how the three different disorders stack up: 

 

Autism

Autistic disorder (or “classic” autism), which is what most people think of when they hear the word “autism,” typically involves significant language delays, social and communication impairments, and unusual behaviors and interests. Many children with this form of autism also have intellectual disabilities, though not all do. “People with autism are fairly disconnected in a behavioral way,” Dr. Rowe says. “They may hear everything going on but not have the expressive language skills to respond in the same way as their peers.” 

A child must have six or more of the following characteristics, including at least two from the first category and one each from the second and third categories:

 

Marked difficulties in social interactions, including at least two of the following:

  • Problems in the use of multiple nonverbal behaviors such as eye-to-eye contact, facial expressions, body postures, and gestures to regulate social interaction
  • Failure to develop relationships with peers in a way that’s appropriate to the child’s developmental level
  • A lack of spontaneous efforts to share enjoyment, interests, or achievements with other people
  • A lack of social or emotional reciprocity

 

Marked impairments in communication abilities, including at least one of the following:

  • A delay in or total lack of the development of spoken language (not accompanied by an attempt to compensate through alternative modes of communication such as gesture or mime)
  • Serious problems with initiating or sustaining a conversation with others (in children who have adequate speech)
  • Repetitive use of language or idiosyncratic language
  • Lack of varied, spontaneous make-believe play or social imitative play that’s appropriate to the child’s developmental level

 

Restricted, repetitive patterns of behavior, interests, and activities, including at least one of the following:

  • A severe preoccupation with one or more interests that is abnormal in intensity or focus
  • A seemingly inflexible adherence to specific, nonfunctional routines or rituals
  • Repetitive motor patterns such as hand flapping or body rocking
  • A persistent preoccupation with parts of objects

 

Asperger’s syndrome
With Asperger’s syndrome, people usually have milder versions of the social challenges and unusual behaviors and interests that are associated with classic autism. These children usually do not have difficulties with speech or nonverbal communication, nor do they have intellectual disabilities. “People with Asperger’s typically have good speech and cognitive function but they have difficulty communicating with people in a socially acceptable way,” Dr. Rowe says. “They know something’s different about them, and they can feel misunderstood when they try to make connections with people, but they don’t know how. This can leave them feeling angry or depressed.”

The following criteria are used to diagnose Asperger's:

Problems with social interaction including at least two of the following:

  • Trouble using nonverbal behavior such as eye-to-eye contact, facial expressions, body postures, and gestures to regulate social interactions
  • Failure to develop relationships with peers in ways that are appropriate to the child’s age and stage of life
  • A lack of spontaneous efforts to share enjoyment, interests, or achievements with other people
  • A lack of social or emotional reciprocity

 

Restricted, repetitive patterns of behavior, interests, and activities, including at least one of the following:

  • A severe preoccupation with one or more interests that is abnormal in intensity or focus
  • A seemingly inflexible adherence to specific, nonfunctional routines or rituals
  • Repetitive motor patterns such as hand flapping or body rocking
  • A persistent preoccupation with parts of objects

These developmental disturbances cause significant problems in social interactions, at school, and in other important areas of a child’s life. There’s no significant delay in language development (in other words, the child is uttering single words by age two and using phrases by age three). There’s also no significant delay in cognitive development or in the development of age-appropriate abilities to do things for himself, in adaptive behavior or in curiosity about the child’s own environment.

 

Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS)

With PDD-NOS, which is sometimes called “atypical autism,” a person may have some symptoms of classic autism and some symptoms of Asperger’s syndrome but not enough to be diagnosed with either one. Children with PDD-NOS typically have fewer and more mild symptoms than those with “classic” autism but they may have communication problems (whereas those with Asperger’s don’t). According to the DSM-IV, this diagnosis is used when a child has a severe and pervasive impairment in her development of reciprocal social interaction, an impairment that’s related to problems with verbal or nonverbal communication skills or to the presence of repetitive behavior, interests, and activities. Other conditions, such as schizophrenia, must also be ruled out before a child can receive this diagnosis.

Complicating matters, a panel of experts working on the DSM-V is proposing to eliminate the individual ASD classifications and use a new general category called “autism spectrum disorders” instead. These proposed changes are somewhat controversial because it isn’t clear how they would affect the availability of support services for people with ASDs, and some people with Asperger’s syndrome are particularly upset about the elimination of their diagnosis. At this point, the changes are not a done deal and are still being debated; the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). It will be published in May 2013.

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