The first randomized controlled trial of this straightforward intervention suggests that playing recordings of a mother’s voice to premature infants could expedite their brain maturation processes. This method may eventually enhance language development in babies born prematurely.

Premature birth alters brain structure, leading to potential language disorders and affecting later communication and academic success. A mother’s voice and heartbeat can foster the development of auditory and language pathways. Unfortunately, parents may not always be able to physically be with their infants in the neonatal units.

To explore whether this absence could be compensated for through recordings, Katherine Travis and her team at Weill Cornell Medicine in New York conducted a study with 46 premature infants born between 24 and 31 weeks gestation, all situated in the neonatal intensive care unit.

We recorded mothers reading from children’s books, including selections from A Bear Named Paddington. Half of the infants listened to a ten-minute audio segment twice every hour overnight between 10 PM and 6 AM, increasing their daily exposure to their mother’s voice by an average of 2.7 hours until they reached their original due date. The other infants received similar medical care but were not exposed to recordings.

Upon reaching their due date, these infants underwent two MRI scans to evaluate the organization and connectivity of their brain networks. The results indicated that those who heard their mother’s voice at night exhibited more robust and organized connections in and around the left arcuate fasciculus, a crucial area for language processing. “The structure appeared notably more developed,” said Travis. “The characteristics matched what one might expect to find in older, more mature infants.”

The scans also suggested that this maturation could be linked to increased myelination— the creation of a fatty sheath that insulates nerve fibers, enhancing the speed and efficiency of signal transmission within the brain. “Myelination is crucial for healthy brain development, especially in pathways that support communication and learning,” noted Travis.

Previous studies have indicated that delayed development of these brain areas correlates with language delays and learning challenges. The latest findings imply that targeted speech exposure could improve these outcomes.

However, is it truly vital for infants to hear their mother’s voice rather than others? While this study did not address that, earlier research explains the phenomenon. Babies start hearing around the 24th week of pregnancy, and continue to recognize their mother’s voice after birth due to early exposure in the womb. Travis explained, “This voice is biologically significant and may be especially appealing to the developing brain.”

Nonetheless, Travis emphasizes that language exposure from other caregivers is also critical for language development, and future studies will explore this aspect further.

The intervention is straightforward and can easily be integrated into care protocols. However, David Edwards from Evelina London Children’s Hospital cautioned against overinterpreting the findings. “Given the small sample size, additional control groups, including different audio sources and forms of auditory stimulation, should be evaluated,” he suggested.

Travis and her research team aim to validate these results in larger trials involving medically vulnerable infants. They will continue to monitor current participants to determine if the observed brain differences result in tangible improvements in language and communication skills as these infants grow.