The altered development of a part of the brain region essential for hearing and understanding sound in preterm infants is associated with poorer language skills in early childhood, according to a study.
The neural machinery that supports hearing is typically functional for 15 weeks before birth, which makes infants sensitive to speech and language while still in the womb.
However, disturbances in the development of the auditory cortex may be the cause of speech and language disabilities at 2 years, researchers at the University of Illinois said.
The team focused on the primary auditory cortex, which is the first cortical region to receive auditory signals from the ears through other parts of the brain, and the non-primary auditory cortex, which plays a more sophisticated role in processing of those stimuli.
The analysis revealed that the primary auditory cortex matures earlier, but more slowly than the non-primary auditory cortex, which changes rapidly in the last 10 weeks of the typical gestation period.
Differences in the development of the non-primary auditory cortex of premature infants were associated with the reduction of expressive language ability, such as gesticulation and vocabulary, in a two-year follow-up evaluation.
"We have an understanding of how the auditory brain develops in premature babies," said lead author Brian Monson, a professor at the University.
"We know from previous research in term newborns that not only fetuses are listening, but they are also listening and learning," Monson added.
For the study, published in the journal eNeuro, the team examined 90 premature babies born before 30 weeks of gestation and 15 full-term babies. The team used diffusion neuroimaging to study the development of the auditory cortex in babies' brains.
"This technique measures the diffusion of water in brain tissues, which can inform a lot about the development of neurons and axons," Monson said. "It's exciting for me that we can use this technique to help predict the ability of language in babies born prematurely," Monson noted.