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New Imaging Reveals ADHD Kids Have Smaller Brain Area

Best look yet into disorder could pave way for therapies

THURSDAY, Nov. 20, 2003 (HealthDayNews) -- Researchers have gotten the best-ever brain images of children with attention-deficit hyperactivity disorder (ADHD), an achievement in basic science that they hope will lead to better treatment of the condition.

The National Institute of Mental Health estimates that 3 to 6 percent of American schoolchildren are affected by ADHD at one time or another. Their learning ability and social activity are hindered by a poor attention span, impulsive behavior, and persistent restlessness, symptoms that can be lessened by drug treatment.

Previous images have shown that brains of children with ADHD differ from those of children without the condition, says Dr. Elizabeth R. Sowell, assistant professor of neurology at the University of California, Los Angeles, in whose Laboratory of Neuro Imaging the work was done.

The new images show that ADHD brains have smaller frontal and temporal lobes, regions involved not only in the control of attention but also in regions involved in impulse control, says Dr. Bradley S. Peterson, a professor of psychiatry at Columbia University and the New York State Psychiatric Institute, who set up the study.

The images "localize those differences in a way that has not been done by other research groups," Sowell says. Some of the images, and a report on how they were obtained and what they might mean, are published in the Nov. 22 issue of The Lancet.

The laboratory used the same magnetic resonance imaging technology as previous studies. The raw MRI data are then processed by advanced computer techniques. "The kind of method we use to analyze the data allow us to see in greater detail where the changes occur," Sowell says.

Images of 27 children and adolescents with ADHD were compared to those of 46 unaffected children.

The imaging was done at UCLA because "they have cutting-edge, very detailed imaging procedures," Peterson explains.

Having these highly detailed images can help in development of new drug treatments, Peterson says. "Because different regions of the brain have different cells types and different neurotransmitters, knowing which regions of the brain are most prominently affected can narrow the search for which chemical systems are more affected," he says.

Neurotransmitters are molecules that transmit information between brain cells, and so are a major target of drug treatment.

But the images can also help "people who work with these children," Sowell says. "Knowing which part of the brain is affected might help them come up with different behavioral treatments."

The study is just beginning, Peterson adds. "The next phase of the work will be to see whether the magnitude of the abnormalities in these individuals might influence the course of the condition, their response to medications, and which medications different children respond to," he says.

Future studies might start with younger children, Sowell says. A series of brain images of children affected by ADHD can help tell "whether these children are born with these structural abnormalities, or whether they develop with time," she says.

"We have to interpret these findings in light of what happens in normal development," she adds.

More information

An overview of ADHD is given by the National Institute of Mental Health or Children and Adults with Attention-Deficit/Hyperactivity Disorder.

SOURCES: Elizabeth R. Sowell, M.D., assistant professor of neurology, University of California, Los Angeles; Bradley S. Peterson, M.D., professor of psychiatry, Columbia University and New York State Psychiatric Institute, New York City; Nov. 22, 2003, The Lancet
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