Autism diagnosis by brain scan a possibility

By Dr. Ananya Mandal, MDSep 5 2011

A team of Stanford scientists have found that the brains of autistic children have a distinctive topography and could be captured using new imaging techniques. This could someday create a template for the autistic brain that could be used to diagnose kids at a very early age they claim.

Detailed, computerized analyses of MRI scans showed a pattern of organization, especially in regions of the brain dedicated to communication and self-awareness, that was particular to children with autism, according to the new research, which was published online Friday in the journal Biological Psychiatry.

Scientists warn that the results are far from being applied to real children. But they could be used not just for diagnoses, but to refine treatments and offer a better understanding of how autism affects the brain. Dr. Antonio Hardan, a child psychiatrist and an author of the Stanford study said, “Older kids, you just talk to them and you know they have autism. But the 2-year-old where you don't have a good idea what's going on with him, whether he's autistic or not, this tool could help…And having this kind of tool might also help you determine what kind of treatment the individual will be getting.”

The Stanford study looked at the brain scans of 24 autistic children between ages 8 and 18, and compared them with scans of 24 children without autism. The study sectioned the scans into tiny cubes and then used computer analysis to compare the size and structure of individual cubes in autistic and non-autistic brains. That allowed scientists to get a much more detailed picture of the specific areas that differ between the brains. The resulting brain maps applied to 80 to 90 percent of the children with autism. If the maps can be replicated in a larger group of children and in children at a younger age, they could be used to help diagnose autism.

“This is a potential biomarker, although how much of a predictive value it has remains to be investigated,” said Vinod Menon, a professor of neurology and psychiatry who led the Stanford study. “In principle, it will tell you whether the individual is more likely to be on the typically developing side or the autism side.”

“We could discriminate between typically developing and autistic children with 92 percent accuracy,” based on the volume of gray matter in one part of the brain, Lucina Uddin, first author of a new study and instructor in psychiatry and behavioral sciences at Stanford University School of Medicine, said in a university news release.

Autism affects roughly 1 in 100 children in the United States, and rates have increased significantly in the past 20 years. As parents and doctors become increasingly aware of the disorder and its lifelong complications, research into diagnosing and treating autism has exploded. Diagnosis has improved significantly, and on average, children are diagnosed at about age 3. But the diagnostic process is difficult and dependent on the skill of the doctor or therapist doing the diagnosis.

Autism experts would prefer that most children be diagnosed well before age 3, when the disorder has already started to affect their verbal and social skills. If doctors can start treating autism before brain damage has occurred, they may be able to avoid some of the worst effects and improve the long-term outlook for children.

“Lots of people are looking for biologic fingerprints that we can use reliably to identify kids very early on, ideally before any manifestation of the disorder,” said Lisa Croen, director of the Autism Research Program for Kaiser Permanente Northern California.

Croen and other Kaiser researchers are looking at other types of biomarkers, such as molecular or genetic signatures that might be found with a simple blood or saliva test. Such tests could be done on newborns or even pregnant mothers to help identify children who are at risk of developing autism.

She's not convinced that brain scans like those studied at Stanford will be useful as a screening tool in finding children with autism, but they could someday help doctors better tailor their treatments of young patients. Autism symptoms can vary widely among patients, and often affect language, social skills and behavioral development she explained.

Behavioral pediatrician Andrew Adesman, said that it is not yet clear if imaging will prove useful in the clinical setting. Adesman is chief of developmental and behavioral pediatrics at Steven & Alexandra Cohen Children’s Medical Center of New York. “That is the $64,000 question,” he says. “We are still pretty far away from that, and I don’t think this study brings us that much closer.”

Adesman says the fact that the Stanford study did not include children younger than 8 or children with Asperger’s and other non-autism disorders limits the interpretation of the findings.

Autism imaging researcher Nicholas Lange, added that it remains to be seen if brain imaging can help distinguish between autism and other developmental disorders since most studies have compared autistic children to those who were developmentally normal. Lange is an associate professor of psychiatry and biostatistics at Harvard Medical School. Although he said he is optimistic that brain imaging will one day prove clinically useful, Lange said that much more research is needed.