Autism Diagnosis

Autism is difficult to diagnose. When the diagnosis is made, it can be heartbreaking to parents.

Parents are usually the first to suspect something is wrong. A previously normal child will suddenly act odd. Language development may stop or regress; social reactions may become inappropriate or disappear altogether. Or, bizarre behavior may appear, such as tantrums or obsessive repetition. Sometimes symptoms appear after vaccination, fever, infection, or other event. Any symptoms should be mentioned at routine doctor visits, where they will be explored to determine if they warrant referral to a specialist.

Regressive vs. Early Onset Autism

One way of classifying autism is by its onset pattern. The majority of cases are early onset, where a child shows symptoms during the first year of life. Regressive cases develop skills that are then lost at some time after the first year.

• An estimated 15-30% of autism cases are regressive.
• Regression usually occurs between 14 and 24 months of age, and is not considered regressive autism if it occurs after 36 months of age.
• Loss of language is the symptom most commonly noticed first, often accompanied by loss of eye contact.
• Also common is a loss of interest in social interactions.

First Steps Toward Diagnosis

Professionals who specialize in autism—child psychiatrists, child psychologists, developmental pediatricians, and pediatric neurologists—will observe the child's behavior, social contacts, and communication skills. They will assess mental and social skills and develop a detailed history of the child's behavior. Some doctors ask parents to bring in videotapes of the child at home. Photo albums and other records may help in identifying time sequences.

If autism is suspected, other tests may include:

• Psychological tests
• IQ tests
• Medical tests to investigate other related conditions. These may include:
  • Blood tests
  • Urine tests
  • DNA and chromosome testing
  • Electroencephalogram (EEG)
  • Magnetic resonance imaging (MRI)

Psychological Tests

A variety of age-appropriate questionnaires and skill tests compare a child's abilities and responses to standards established by testing thousands of "normal" children. Some test motor skills, like stacking blocks. Some test visual and coordination skills. Some compare daily activities with others of the same age.

Gilliam Autism Rating Scale (GARS) 2

GARS-2 is a revised version of the original GARS and is used to diagnose autism in individuals between the ages of 3 and 22. There are 42 test items based on definitions of autism in the DSM-IV and agreed upon by the Autism Association of America.
Items on the scale are organized into three categories: stereotyped behaviors, communication, and social interactions.

IQ Tests

These are comparative evaluations of individuals at the same age with respect to age-appropriate intellectual skills, like pattern recognition and problem solving. An IQ is the ratio of the child's calendar age to his intellectual "age"—the average performance of others at a given age. For example, if a 5-year-old child performs like a 10-year old, his IQ would be 200.

Blood and Urine Tests

Thousands of tests evaluate physical health. Some are done routinely, like a blood count and urinalysis. Others types of blood and urine tests are done only rarely for unusual conditions. Your doctor will select all that are appropriate.

DNA and Chromosome Testing

Genetic disorders are detected by looking at your genes. Certain genetic disorders are associated with autism, like tuberous sclerosis and fragile X syndrome.

Electroencephalogram (EEG)

This is a test that records the brain's activity by measuring electrical currents through the brain. Abnormalities may indicate a seizure disorder, which is commonly associated with autism.

Magnetic Resonance Imaging (MRI)

MRI uses magnetic waves to make pictures of the inside of the body. In this case, it is done to look for abnormal brain growth that may be related to the cause of your child’s autism.

• Screening for Autism

References:

Behrman RE, et al. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, PA: Saunders; 2007.

DynaMed Editors. Autism spectrum disorders. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what.php . Updated September 13, 2010. Accessed September 13, 2010.

Goetz CG. Goetz’s Textbook of Clinical Neurology. 3rd ed. Philadelphia, PA: Saunders; 2007.

Jacobson JL, Jacobson AM. Psychiatric Secrets. 2nd ed. Philadelphia, PA: Hanley & Belfus; 2001.

National Institute of Mental Health. Autism spectrum disorders (pervasive developmental disorders): treatment options. National Institute of Mental Health website. Available at: http://www.nimh.nih.gov/health/publications/autism/treatment-options.shtml . Accessed September 10, 2010.

Stern TA, et al. Massachusetts General Hospital Comprehensive Clinical Psychiatry. 1st ed. Philadelphia, PA: Mosby Elsevier; 2008.

Tafiadis, Dionysios et al (2008). The Gilliam Autism Rating Scale (GARS - 2), a pilot study for the Greek autistic population. Annals of General Psychiatry, accessed at http://resources.ciis.edu:2067/content/j57x205647703312/fulltext.html