Abnormal brain anatomy in children with ADHD

Children with attention deficit hyperactivity disorder (ADHD) display anatomical brain abnormalities beyond chemical
imbalance, according to research presented at the annual meeting of the Radiological Society of North America (RSNA).
Stimulant medications prescribed to balance brain chemistry appear to normalize some of these brain irregularities, a second
study reported.


"We found abnormality of the fiber pathways in the frontal cortex, basal ganglia, brain stem and cerebellum," said lead
author of both studies, Manzar Ashtari, PhD., associate professor of radiology and psychiatry at North Shore-Long Island
Jewish Health System in New Hyde Park, N.Y.



"These areas are involved in the processes that regulate attention, impulsive behavior, motor activity, and inhibition--the
key symptoms in ADHD children," Dr. Ashtari said. "They are also known to be part of a bigger circuit in the brain that
establishes communication between the frontal lobe and cerebellum."


According to the National Institute of Mental Health (NIMH), ADHD affects 3 to 5 percent of children in the United States.
Children with ADHD have difficulty controlling their behavior or focusing their attention.


Using diffusion tensor imaging (DTI) to compare 18 children with diagnosed ADHD with 15 control children to evaluate the
brain's white-matter fiber development, Dr. Ashtari's team found differences in the brain fiber pathways that transmit and
receive information among brain areas.


"Typically ADHD is described as a chemical imbalance, but our research has shown that there may also be subtle anatomical
differences in areas of the brain that are important in this disorder," said co-principal investigator Sanjiv Kumra, M.D., a
psychiatrist at the Zucker Hillside Hospital in Glen Oaks, N.Y.


In the second study, the researchers found that children who had received stimulant treatment for ADHD had fewer white matter
abnormalities than children who did not receive medication.


Patients consisted of two groups, each comprised of 10 children with ADHD. The first group had not taken medication or had
been minimally exposed to medications. The second group was exposed to stimulants for an average of 2.5 years. Each of these
groups was compared with 10 age- and gender-matched controls. The medicated ADHD children exhibited a normalization effect in
fiber pathways of several brain areas.


"The findings from this small, cross-sectional study indicate that the therapeutic effect of stimulants may involve a brain
normalization process," Dr. Kumra said.


Most people diagnosed with ADHD in childhood continue to have problems in adolescence and adulthood. "Despite progress in the
assessment, diagnosis and treatment of ADHD, this disorder and its treatment have remained controversial," said co-author of
the stimulant study, Andrew Adesman, M.D. "This study is yet further proof that children with ADHD differ at a
neurobiological level as compared to children without the disorder." Dr. Adesman is chief of developmental and behavioral
pediatrics at Schneider Children's Hospital in New Hyde Park, N.Y.


Dr. Ashtari said further studies with larger patient groups must be conducted before offering parents advice for diagnosis or
treatment.


Co-authors are Babak Ardekani, Ph.D., Shree Bhaskar, M.D., Tana Clarke, B.S., and Joseph Rhinewine, M.A. (DTI study only).
The research was sponsored by an NIMH grant.


Note: Copies of RSNA 2004 news releases and electronic images will be available online at http://rsna/press04 beginning Monday, Nov. 29.


RSNA is an association of more than 37,000 radiologists, radiation oncologists and related scientists committed to promoting
excellence in radiology through education and by fostering research, with the ultimate goal of improving patient care. The
Society is based in Oak Brook, Ill.


Editor's note: The data in these releases may differ from those in the printed abstract and those actually presented at the
meeting, as researchers continue to update their data right up until the meeting. To ensure you are using the most up-to-date
information, please call the RSNA newsroom at (312) 949-3233 between Nov. 27 and Dec. 3.


Contact: Maureen Morley



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Radiological Society of North America