Study Maps Brain Abnormalities in Autistic Children

December 5, 2007

By Susan Kelly

CHICAGO (Reuters) - Autistic children have more gray matter in areas of the brain that control social processing and sight-based learning than children without the developmental disability, a small study said on Wednesday.

Researchers combined two sophisticated imaging techniques to track the motion of water molecules in the brain and pinpoint small changes in gray matter volume in 13 boys with high-functioning autism or Asperger syndrome and 12 healthy adolescents. Their average age was 11.

The autistic children were found to have enlarged gray matter in the parietal lobes of the brain linked to the mirror neuron system of cells associated with empathy, emotional experience and learning through sight.

Those children also showed a decrease in gray matter volume in the right amygdala region of the brain that correlated with degrees of impairment in social interaction, the study found.

The researchers assessed patient brain function using a combination of diffusion tensor imaging (DTI) and a new imaging method called apparent diffusion coefficient based morphometry (ABM). Their findings were presented at the annual meeting of the Radiological Society of North America in Chicago.

Unlike earlier technology, the technique can detect subtle changes in thousands of small sections of the brain, said the study's lead author, Manzar Ashtari of the Children's Hospital of Philadelphia. "Now we have sharper tools," Ashtari said in an interview.

Larger amounts of gray matter in the left parietal area of the brain correlated with higher IQs in the control group of children but not in the autistic children, because that section of gray matter is not functioning properly, Ashtari said.

Autism affects about 1.5 million Americans, according to the Centers for Disease Control and Prevention. Considered the fastest-growing developmental disability in the United States, autism typically appears in the first three years of life and hinders social interaction and communication skills.

More studies that look at brain structure and function together are needed to better understand how the minds of autistic children work, Ashtari said, with the hope of devising earlier intervention strategies to treat the condition.

"If more and more people truly prove that mirror neurons in general are responsible and are involved in children with autism, then I believe more and more people will think, how do we actually strengthen them? What can we do to make them actually work normally?" Ashtari said.

(Editing by Eric Beech)

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