For all the challenges faced by preterm babies, limited research explores how birth early in the third trimester can affect hearing and understanding speech. A team of researchers, using MRI, found children born prematurely were more likely to face speech and language problems by the age of 2.
"We have a pretty limited understanding of how the auditory brain develops in preterm infants," said Brian Monson, with the University of Illinois in Champaign, who led the study, published online Jan. 15 in eNeuro. "We know from previous research on full-term newborns that not only are fetuses hearing, but they're also listening and learning."
The team found 90 premature infants who had undergone regular MRI while in St. Louis Children's Hospital Neonatal Intensive Care Unit. A control group featured 15 full-term babies who underwent MRI within the first four days of life.
Researchers used diffusion tensor imaging to focus on the primary and nonprimary auditory cortices.
"We wanted to know: What is the relationship between these two regions? Do they mature at the same time but at different rates? Do they mature at different times but similar rates?" Monson said. "A different rate of maturation may render one tissue more vulnerable to injury or disruption associated with preterm birth."
At 26 weeks of gestation, the primary auditory cortex was developmentally advanced compared to the nonprimary auditory cortex. But in the next 14 weeks of gestation, the nonprimary auditory cortex matures quickly, catching up to its primary counterpart.
But both regions appeared less developed at 40 weeks in infants born preterm. Disruptions in development, according to the team, may lead to speech and language problems in life.
"It's exciting to me that we may be able to use this technique to help predict later language ability in infants who are born preterm," he said. "I hope one day we also will be able to intervene for those infants who may be at greatest risk of language deficits, perhaps even before they begin to use words."
The full study is available here.