Premature infants with no
obvious problems in the structure of their brains may still have subtle
chemical differences compared with full-term babies, a new study finds.
Researchers said it's not
clear if these microscopic differences are actually signs of trouble. But they
hope that a deeper understanding of preemies' brain development will eventually
be useful in improving their outlook.
infants are healthy, but they are at increased risk of problems," said
lead researcher Stefan Bluml, of Children's Hospital Los Angeles. Those
problems can include learning disabilities, behavioural issues such as
attention-deficit/hyperactivity disorder and autism.
To gain more insight into
preemie brain development, Bluml's team used magnetic resonance spectroscopy
(MRS) to image infants' brains on the microscopic level.
All 81 babies in the study 30
preterm and 51 full-term had normal brain structure, based on standard MRI
scans. But when the researchers used MRS, they saw "biochemical"
differences between the premature and full-term infants.
In general, the preemies
showed an "early start" in the brain's white matter development,
which put it out of sync with the maturation of the brain's gray matter. Gray
matter can be seen as the brain's information-processing centres, while white
matter is like the wiring connecting those centres.
Bluml described it as a
"false start" in preemies' white matter development, and the trigger
appears to take place after birth. It's not clear what that trigger is, but one
possibility, according to Bluml, is oxygen.
The foetal brain, he
explained, is designed to develop in a low-oxygen environment. At birth, babies
are thrust into a much more oxygen-rich world, and preemies' brains might not
be quite ready for that.
Still, it's not clear if
the brain differences Bluml's team found are "bad". "These might
be necessary compensatory mechanisms," Bluml said. "At present, it's
not clear. We're just saying there are differences."
The findings are scheduled
for presentation at the Radiological Society of North America annual
meeting, in Chicago. Research presented at meetings should be viewed as
preliminary until published in a peer-reviewed medical journal.
One expert agreed that the
significance is unknown. But it would be interesting to follow these infants
over time, to see if the chemical differences are associated with any learning
or behaviour issues later, said Dr Madhavi Koneru, a neonatologist who treats
newborns at McLane Children's Hospital at Scott & White in Temple, Texas.
"What does this mean
down the road? That's what we want to know," Koneru said.
In recent years, medical
advances have allowed more and more of the tiniest preemies to survive. But,
Koneru said, "Surviving is not enough. We want them to thrive."
She said she thinks that
brain-imaging research like this will one day aid in improving preemies'
For now, Bluml said, they
are just trying to map the course that preemies' brain maturation typically
takes. "Our goal is to establish certain landmarks of brain
development," he said.
Eventually, he added, MRS
scans could potentially be used to evaluate whether a therapy for preterm
babies is actually having an effect on brain development.
The March of Dimes has more
on preterm birth.
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