A five-minute brain scan can reveal the maturity of a child's brain, according to a new study. The results could be used to track abnormal brain development and catch brain disorders like autism early.
The study, published online this week in the journal Science, uses a specialized method of mathematically sifting through magnetic resonance imaging (MRI) data to form a picture not just of the brain's structure, but the way its various regions work together.
"The beauty of this approach is that it lets you ask what's different in the way that children with autism, for example, are off the normal development curve versus the way that children with attention-deficit disorder are off that curve," study researcher Bradley Schlaggar, a pediatric neurologist at the Washington University School of Medicine in St. Louis, said in a statement.
Measuring mental maturity
As the human brain matures, its organization changes. The tightest connections in young children's brains are between areas that are physically near one another. As the brain ages, these connections shift and networks connecting distant regions become the strongest.
To measure these shifts over time, Schlagger and his colleagues used a method called resting state functional connectivity. As the participants rest in an MRI scanner, the researchers use the machine to measure increases and decreases in blood flow to various brain regions. Correlating the blood flow changes allows the researchers to learn which regions communicate and work together.
The researchers collected five-minute MRI scans from 238 healthy people ages 7 to 30. They ran data on 13,000 functional brain connections through a tool called a support vector machine, which crunched the numbers and selected the 200 connections that best predicted brain maturity. The result was a single index of the maturity of each person's brain. After the data were analyzed, researchers were able to predict whether subjects were children or adults just from their brain organization. Much like a child's height or weight chart, the data formed a curving line that tracks the average path of normal brain development.
Brains on a curve
Traditional methods of looking at brain structure alone with an MRI often miss kids with even severe psychiatric disorders, Schlaggar said. That's because brain structure doesn't always correlate with psychiatric disease.
Mapping out the brain's function, on the other hand, can lead to psychiatric insights. A study of 20 cocaine abusers and 20 healthy people published in May in the journal PloS One, for example, found differences in functional connectivity in the drug abusers' brains. And a December 2009 study in the journal Magnetic Resonance in Medicine found that the same methods used by Schlagger and his team could be useful in distinguishing the brains of depressed patients from healthy brains.
The researchers hope their new findings could be used to create a normal brain growth chart. Kids at risk for developmental disorders could be scanned to see if their brain development is off course. If so, doctors might be able to start treatment before symptoms begin, Schlagger said.
MRIs are expensive, the researchers warn, so they're unlikely to show up at pediatricians' offices just yet. But study researcher Nico Dosenbach, a pediatric neurology resident at St. Louis Children's Hospital, said many children with psychiatric disorders or who are at risk for the disorders already get MRIs.
"Five more minutes in the scanner,” Dosenbach said, “won't add that much to the cost."
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