A Long Island, New York, researcher has pinpointed for the first time brain regions in children with autism linked to ritualistic repetitive behaviour, the insatiable desire to rock back and forth for hours or tirelessly march in place.
Collaborating with investigators at Duke University and the University of North Carolina in Chapel Hill, Dr. Keith Shafritz, an assistant professor of psychology at Hofstra University, unmasked brain regions in children with autism typified by reduced neural activity. In a series of high-tech mapping studies, he compared brain images of children with autism to those of neurologically normal youngsters.
Repetitive behaviour is one of autisms core traits and has driven some parents to extremes as they try to distract a child to engage in other activities.
Shafritz and colleagues used a form of magnetic resonance imaging to explore sites in the brain. They reported their findings in the current issue of Biological Psychiatry.
In children with autism, Shafritz found deficits in specific regions of the cerebral cortex, the outer layer of grey matter linked to all higher human functions, including repetitive behaviour. He also mapped deficits in the basal ganglia, a region deep below the cerebral hemispheres.
We like to think about the research process as discovering clues on why people engage in certain behaviours, Shafritz said last week.
We were able to identify a series of brain regions that showed diminished activity when people were asked to alter certain behaviours, and were not able to do so.
Autism is a neurodevelopmental disorder that is rapidly becoming a major public policy issue. Health officials in the US estimate it affects one in every 150 children.
School systems lack a sufficient number of appropriately trained teachers and social services departments are overwhelmed by parents in need of support and respite care.
Amid social concerns are the plodding attempts to understand the disorders basic biology. Some scientists are scanning the human genome in search of suspect DNA. Others like Shafritz are exploring the geography of the brain.Edward Carr, a professor of psychology at Stony Brook University, said the Shafritz discovery is important because it helps demystify repetitive behaviour.
Repetitive behaviour is sometimes called self-stimulatory behaviour. A very common form of it is body rocking; a child will do it for hours, Carr said. Another child may wave his or her hands back and forth in front of their eyes. This is very common and its called hand flapping. They extend their arms forward and wave their hands in front of them. Some kids will take 100 crayons and line them up over and over. If you move one of the crayons they get very upset. It might lead to a tantrum, a major outburst of problem behaviour.
Even though the brain mapping revealed sites associated with repetitious behaviour, Shafritz emphasised these areas are not associated with injurious acts, which may occur as a result of dysfunctions elsewhere in the brain. Some children repeatedly slam their heads against a wall and indulge in other self-injurious behaviour.
Still, Shafritz found a relationship between the newly identified brain areas and overlapping regions linked to schizophrenia, obsessive compulsive disorder and attention deficit hyperactivity disorder.
Dr. Anil Malhotra, director of psychiatric research at Zucker Hillside Hospital in Glen Oaks, N.Y., said he is not surprised. He, too, is studying links between autism and schizophrenia, and autism and obsessive compulsive disorder.
This is an area of great interest, Malhotra said, adding that autism and schizophrenia are related because both disorders are marked by problems with social interaction.
We also see an overlap between (obsessive compulsive disorder) and autism, Malhotra said.
Los Angeles Times