Facts

How is autism diagnosed?

Autism is classified as one of the pervasive* developmental disorders. Some doctors also use terms such as "emotionally disturbed" to describe people with autism. Because it varies widely in its symptoms, autism may go unrecognized, especially in mildly affected individuals or in those with multiple handicaps.

Absence or impairment of imaginative and social play
Impaired ability to make friends with peers
Impaired ability to continue a conversation with others
Stereotyped, repetitive, or unusual use of language
Restricted patterns of interests that are abnormal in intensity or focus
No flexibility to specific routines or rituals
Preoccupation with parts of objects

Children with some symptoms of autism, but not enough to be diagnosed with the classical form of the disorder, are often diagnosed with pervasive developmental disorder - not otherwise specified (PDD - NOS). People with autistic behavior but well-developed language skills are often diagnosed with Asperger's syndrome. Children who appear normal in their first several years, then lose skills and begin showing autistic behavior, may be diagnosed with childhood disintegrative* disorder (CDD). Girls with Rett syndrome, a sex-linked genetic disorder characterized by inadequate brain growth, seizures, and other neurological problems, also may show autistic behavior. PDD - NOS, Asperger syndrome, CDD, and Rett syndrome are referred to as autism spectrum disorders.

Since hearing problems can be confused with autism, children with delayed speech development should always have their hearing checked. Children sometimes have impaired hearing in addition to autism. About half of people with autism score below 50 on IQ tests, 20 percent score between 50 and 70, and 30 percent score higher than 70. However, estimating IQ in young children with autism is often difficult because problems with language and behavior can interfere with testing. A small percentage of people with autism are savants. These people have limited but extraordinary skills in areas like music, mathematics, drawing, or visualization.

What causes autism?

Autism has no single cause. Researchers have identified a number of genes that play a role in the disorder. In some children, environmental factors also may play a role in development of the disorder. Studies of people with autism have found abnormalities* in several regions of the brain, including the cerebellum, amygdala, hippocampus, septum, and mamillary bodies. Neurons in these regions appear smaller than normal and have stunted nerve fibers, which may interfere with nerve signaling. These abnormalities* suggest that autism results from disruption* of normal brain development early in fetal* development. Other studies suggest that people with autism have abnormalities* of serotonin or other signaling molecules in the brain. While these findings are intriguing*, they are preliminary and require further study. The early belief that parental practices are responsible for autism has now been disproved.

Do symptoms of autism change over time?

Symptoms in many children with autism improve with intervention or as the children mature. Some people with autism eventually lead normal or near-normal lives. About a third of children with autistic spectrum disorders eventually develop epilepsy. The risk is highest in children with severe cognitive impairment and motor deficits. Adolescence* may worsen behavior problems in some children with autism, who may become depressed or increasingly unmanageable.

PAGE RESOURCES COME FROM NINDS (SEE BIBLIOGRAPHY)

Notice: Materials from this site may not be copied, distributed or transmitted in any way without prior written consent of Spencer Huang.