Under the Hood

Brain Charts, Like Baby Growth Charts, Could Identify Early Signs Of ADHD

intrinsic connectivity networks
Just as pediatricians use growth charts, psychiatrists might create maturity charts for a child’s brain and look for abnormalities in mental development. Phillipe Merle, Getty Images

Much about the human brain remains a mystery, but MRIs show us that distinct webs of wired brain regions “light up” (or simultaneously activate) on a brain scan even when a person is at rest. These intrinsic connectivity networks are considered part of the brain’s functional structure, and from childhood to young adulthood, they will change and evolve. In fact, the normal brain follows a certain path and hits predictable benchmarks of progress. In children for whom brain maturity does not occur as expected, behavior or cognitive problems will likely appear.

Let’s put this knowledge to practical use, suggests Dr. Chandra Sripada, University of Michigan, and her colleagues in a new study. Just as pediatricians use growth charts to measure a child’s physical development, why shouldn’t psychiatrists create their own charts as a point of reference for a child’s brain and look for abnormalities in mental development?

“It is plausible,” wrote the researchers, “that deviations from normative trajectories of network maturation might be predictive of a range of clinically important psychological characteristics and conditions.”

ICNs essentially show you the brain in its ready state, like observing a car engine when it is idling at the curb (not driving the highway). Because ICNs light up when the brain is at rest, any activity occurring is not a sign of mental performance but a sign of neural circuit maintenance. For this reason, psychiatrists see patterns of over-activity or under-activity in the ICNs as a probable basis for brain disorder.

For the current study, Sripada and her team wanted to test the hypothesis that an ICN chart for children might reliably detect problems with attention. The researchers began by gathering data from an existing study, the Philadelphia Neurodevelopmental Cohort, a sample of 9,498 young people who had undergone a variety of tests and measurements, including brain scans. Then, based on this mainly healthy group, they constructed a chart of normal brain maturity for each age — just as pediatricians create their growth charts by looking at average height and weight across a large sample of children.

Next, the researchers looked at the records and tracked two pieces of information for each participant: their scores on a particular performance test and whether or not they’d been diagnosed with attention-deficit/hyperactivity disorder (ADHD). Having identified 25 people who met the criteria for this attention disorder, the researchers looked back at their brain scans from a younger age and discovered abnormal development of their ICNs as compared to the average chart they’d constructed.

“We showed that when individuals deviate from normative maturational trajectories in the development of ICNs, they consistently exhibit worse sustained attention performance,” concluded the authors.

In an editorial, Dr. Philip Shaw of the National Institutes of Health suggests a possible future role for brain growth chart assessments in diagnosis of children already showing behavioral problems. At least for now, the expense and complexity of neuroimaging in its current form prohibit its use as a screening tool.

Source: Kessler D, Angstadt M, Sripada C. Growth Charting of Brain Connectivity Networks and the Identification of Attention Impairment in Youth. JAMA Psychiatry. 2016.

Shaw P. Maps of the Development of the Brain’s Functional Architecture: Could They Provide Growth Charts for Psychiatry? JAMA Psychiatry. 2016.

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