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Brain scan could detect attention deficit disorder WASHINGTON (November 23, 1998 6:04 p.m. EST http://www.nandotimes.com) -- Researchers say a special brain scan can identify children with attention deficit disorder, a behavior syndrome for which millions of kids are placed on powerful drugs. Just as importantly, the finding of a biological "signature" in the brains of those with ADD could help determine a child does not have the disorder, according to the Stanford University researchers. Their announcement, to be published Tuesday in the Proceedings of the National Academy of Sciences, comes just days after a government panel concluded that doctors have no consistent, physical way to identify ADD or diagnose who has it. The brain scan technique needs further testing, however, and could prove expensive. Insurance companies generally do not pay for the special type of brain scan, called a "functional MRI," that is required. A regular MRI can cost more than $1,500, and a functional MRI, available at just a few hospitals, can cost even more. Nevertheless, "we've taken a first step that looks very promising," said John Gabrieli of Stanford's Department of Psychology, the study's co-author. Attention deficit disorder, or ADD, also known as attention deficit hyperactivity disorder, usually is diagnosed in school-age children. The diagnosis is usually based on observed behavior, and some experts believe it is highly subjective, essentially just an educated judgment. Symptoms of ADD include the restless inability to sit still to read, study or even watch television. Often a child cannot play in group games, and a common symptom is the inability to control impulses. Some mild forms of symptoms are common in many children, leading to concerns it is diagnosed too often. "Many people are concerned because the diagnosis remains very subjective," Gabrieli said. "It is possible to misdiagnose a child and miss another condition, or to over-diagnose a child who is merely rambunctious." A biological signature of ADD, in contrast, would allow for "a valid and consistent diagnosis," he said. Mind-affecting drugs such as Ritalin are the most common treatment, but some doctors and parents worry about their long-term effects, which have never been studied. The Stanford study used a special type of magnetic resonance imaging device, the functional MRI, to individually scan the brains of 16 boys between the ages of 8 and 13 while they were playing a simple mental game. The MRI detects which part of the brain responds to specific actions or to drugs. Ten of the boys had been diagnosed with ADD, and six were considered normal. These six were used as a comparison control. In the game, the boys watched letters of the alphabet flash individually on a screen. The boys were to push a button for every letter except X. When X flashed, they were to resist the impulse to press the button. "They were seeing a lot of letters except for X," said Gabrieli. "They got so used to going that it was hard to stop." Since impulse control and poor concentration are a hallmark of ADD, those patients with the disorder did much more poorly than the normal patients, he said. When the researchers compared brain scans, there was a clear difference in brain activity between the ADD patients and the other boys. The boys were next tested after they had been given doses of Ritalin. Curiously, the drug improved the performance of both groups to the same extent. But when the brain scans were compared again, the researchers found that boys with ADD had more activity in the basal ganglia, a brain structure, than they had before taking Ritalin. In contrast, the boys without ADD had less activity in that part of the brain. The test thus gives "a brain signature" that specifically and biologically identifies those with ADD, Gabrieli said. However, it is still preliminary and must be proved by testing both boys and girls and by being duplicated independently in other labs, said Chandan J. Vaidya, the main researcher. It took two years to develop the preliminary test, Vaidya said, and there's no way to estimate how long it will take to perfect so it can be used reliably on patients. By PAUL RECER, AP Science Writer Copyright 1998 Nando Media Copyright 1998 The Associated Press janet paterson - 51 now /41 dx /37 onset - almonte/ontario/canada http://www.newcountry.nu/pd/members/janet/ [log in to unmask]