Children born premature have higher risk of psychiatric disorders due to weaker brain connections

Researchers have shown that key brain networks—those involved in attention, communication, and emotion—were weaker in premature infants than in infants born full term. This finding offers an explanation for why children born prematurely may have an elevated risk of psychiatric disorders, according to a study presented October 19, 2015 at Neuroscience 2015, the annual scientific meeting of the Society for Neuroscience, held in Chicago, IL.

The discovery also offers the hope that interventions might one day improve outcomes in these children, researchers predicted.

“We found significant differences in the white matter tracts and abnormalities in brain circuits in the infants born early compared with those of infants born at full term,” said principal investigator Cynthia Rogers, MD, assistant professor of child psychiatry at Washington University School of Medicine in St. Louis, MO.

Babies born premature are known to have altered gray matter and white matter development. Children born premature also have increased rates of developmental deficits and psychopathology, including ADHD, autism spectrum disorder, and anxiety disorders. Researchers believe these problems are likely due to altered cerebral development, particularly in those children born at the earliest gestational ages. But few studies have concomitantly assessed both structural and functional connectivity in this population.

In this study, researchers compared structural and functional connectivity in 76 infants born prematurely (less than 30 weeks gestational age) with 58 healthy, full term infants (greater than 37 weeks gestational age). Full-term infants underwent MRI within a few days of birth while premature infants were imaged within days of their expected full-term due date. Imaging included resting state functional magnetic resonance imaging (rs-fMRI) and diffusion tensor imaging (DTI).

Analysis of DTI scans demonstrated widespread reductions in white matter tracts (bundles of axons that connect one area of the brain to another) of premature infants compared with full-term infants.

Premature infants also had reduced correlation and covariance within and between 7 canonical resting state networks (RSNs), as demonstrated on rs-fMRI. The greatest differences between full-term and preterm babies were found in the default mode network and in the frontoparietal network. Both of these RSNs encompass brain circuits associated with emotion, and have been previously linked to ADHD and autism spectrum disorders.

These network abnormalities likely contribute to developmental and psychiatric problems that materialize as the children get older, said Dr. Rogers, who treats patients at St. Louis Children’s Hospital in St. Louis, MO.

“The brain is particularly ‘plastic’ very early in life and potentially could be modified by early intervention,” she said. “We usually can’t begin interventions until after symptoms develop, but what we’re trying to do is develop objective measures of brain development in preemies that can indicate whether a child is likely to have later problems so that we can intervene with extra support and therapy early on to try to improve outcomes.”

To that end, Dr. Rogers and her colleagues are continuing to follow the subjects in the course of the children’s development. The researchers have completed follow-up evaluations when the children reached age 2, and again on some at age 5. The researchers plan another round of imaging when the original study participants reach age 9 or 10.