The researchers from the University of North Carolina's Carolina Institute for Developmental Disabilities (CIDD) conducted MRI scans on 148 children at three times: six months, one year and two years. 106 of the children were deemed high risk as they had an older sibling diagnosed with autism.
Eight out of ten of those with a faster growth rate of the surface areas of their brains were found to be diagnosed with autism later on. However, with only 100 at-risk children, the study is too small to be considered definitive - nor should doctors rush to use MRIs to diagnose autism, Heather Hazlett, a psychologist at CIDD.
But many studies like CIDD's can contribute to a better understanding of the autism spectrum disorder, which help develop better diagnostic tools or treatments and cures.
Most drug trials fail due to how heterogeneous autism isAs autism is a very diverse condition, there are only two drugs - risperidone and aripiprazole - that are approved by the US Food and Drug Administration (FDA) for autism and both are just to relieve irritability. There are none that have been approved to treat the core conditions - social impairments or repetitive behaviours.
For example, experts proposed antidepressants such as citalopram and fluoxetine would reduce repetitive behaviours in children with autism, but clinical ideas showed otherwise. A preliminary report in 1998 also suggested that the gut hormone secretin could improve the language abilities of children with autism, but larger studies did not confirm those findings.
Many of these studies involved improper study designs and broad groups of participants that are inappropriate for conditions as heterogeneous as autism, says Eric London, director of the Autism Treatment Research Laboratory at the New York State Institute for Basic Research in Developmental Disabilities.
“That’s the number one reason drug trials fail,” he says.
Biomarkers are better measures than questionnairesThe measures autism researchers usually employ, are not good enough to track shifts in key autism features in response to the drug being tested. Only a few, such as the Vineland Adaptive Behavior Scales have been recommended and even they are suggested with reservations.
These limitations leave researchers stranded as they cannot identify subtle changes in language or social interaction in response to drugs. Therefore some researchers are turning to brain waves and other biomarkers such as eye tracking, electroencephalography (EEG) and levels of various molecules in the blood, to identify potential responders, says Craig Erickson, associate professor of psychiatry at Cincinnati Children's Hospital Medical Centre in Ohio.
Others are teaming up with drug companies and federal agencies to change the way clinical trials are conducted. In a USD28 million four-year project known as the Autism Biomarkers Consortium for Clinical Trials, researchers will follow 200 children with autism for six months, charting their behaviour and brain functioning with a specific set of biomarkers, creating a set of measures to precisely detect changes in trial participants. This would help track how participants respond to treatments and predict who on the spectrum will most likely benefit.
Another project, launched in 2012 in Europe, aims to identify and categorise the subtypes of autism. The USD32 million European Autism Interventions project includes academic researchers and key industry players such as Roche and Pfizer. 450 children with autism will be tracked for up to two years, with their genetic, behavioural and brain imaging information collected to help identify the subgroups of autism.
Should the CIDD's study results become confirmed in a larger study, it could be another "potential biomarker that could be used to identify those infants who perhaps could benefit from early stimulation," says Geraldine Dawson, a clinical psychologist and autism researcher at Duke University who was not involved in the research. MIMS
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