Who should be referred for additional testing?

by Kapila Seshadri, M.D., Audrey Mars, M.D. Who should be referred for additional testing What tests should be performed? What causes autism? What about genetic factors? About the Authors Failure to meet any of these developmental milestones is an absolute indication to proceed with further evaluation:
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What tests should be performed?

Although there is no diagnostic laboratory test for Pervasive Developmental Disorder, tests are often recommended for the following reasons: 1) to search for a cause for having autism, 2) to rule out other medical problems that might look like autism (for example, hearing loss), 3) to detect medical problems that might be co-existing with the Pervasive Developmental Disorder. Any child with delayed language or at risk for autism should be provided with a referral for audiologic testing. A child who does not speak or respond to others speech may have autism or may actually have a hearing problem or some other problems which interferes with speech. Metabolic testing should be considered when there is a history of lethargy, cyclic vomiting, early seizures, mental retardation or unusual facial features. Untreated phenylketonuria (PKU) is an example of a metabolic disorder. Genetic testing, specifically DNA analysis for Fragile X and high resolution chromosome studies (karyotype) are recommended to help identify genetically based disorders and may be particularly useful for future family planning. Cognitive testing by a psychologist, speech/language communication evaluation and an evaluation of sensorimotor skills by an occupational or physical therapist will give greater understanding of your child’s learning strengths and weaknesses. Such evaluations will be useful in planning an appropriate educational program. An EEG (electroencephalogram) may reveal brain wave abnormalities indicating epilepsy and is generally only done if seizures are suspected clinically or if there is a history of regression (significant loss of social and communicative function). Neuroimaging may be indicated by an abnormal neurologic examination not explained by the diagnosis of autism, such as non-symmetrical motor examination, cranial nerve abnormalities, and severe headaches. Routine clinical neuroimaging, such as Magnetic Resonance Imaging (MRI) does not have any role in the diagnostic evaluation of autism at the present time.Back to top

What causes autism?

The cause of autism is not fully understood. When first described in 1943 by Dr. Leo Kanner, it was thought that autism was caused by a lack of warmth and love on the part of the parents. We now know that a child with autism is born with a developmental disability and the parents are not in any way to blame. Neurological damage (with or without a biochemical basis) is now believed to be the cause of autism. Autism occurs more often in children who have had other conditions which affect the brain before birth, such as German Measles (Rubella), phenylketonuria (PKU, a defect in body chemistry), and infantile spasms (a form of epilepsy). There is a higher incidence of seizures (epilepsy) in children with autism, especially around adolescence. Some rare metabolic imbalances have also been linked to autism. Thus there are several findings that point to an abnormality in the brain itself or a disturbance in the body chemistry which affects the brain. Recently, researchers have focused attention on the actual structure of the brain in people with autism. Using the procedure called Magnetic Resonance Imaging (MRI), researchers have found that there may be a structural difference in the cerebellum part of the brain in people with autism. However, at this time, these findings are not specific enough for MRI to serve as a diagnostic test for autism. Back to top There are a number of genetically transmitted and familial factors which have been linked to autism. It is likely that genes inherited from both parents combine with other factors, such as injury to the brain before birth or an illness in early infancy. It may be that what is inherited is an increased susceptibility to develop autism. Researchers have found that a couple with one child with autism has a greater risk of having a second child with autism than a couple without an autistic child. This risk is greatly increased when there is an identified genetic disorder, such as Fragile X Syndrome. Because inheritance patterns differ from family to family, parents who plan to expand their family may wish to seek genetic counseling services to help determine their own relative risk.Back to top

Kapila Seshadri, M.D., is an Associate Professor of Pediatrics at the University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School in New Brunswick, New Jersey.  Audrey Mars, M.D., is affiliated with Developmental Pediatric Associates, Hunterdon Medical Center and is an Associate Professor of Pediatrics at the University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School in New Brunswick, New Jersey.  Drs. Seshadri and Mars are part of the Division of Developmental Disabilities at the University. They perform neurodevelopmental consultations and teach medical students, residents, and fellows. They also participate in research and serve on several committees.