Mother’s voice seems to boost language development in premature babies

Researchers have discovered that playing a recording of a mother’s voice to premature infants may facilitate quicker brain development, based on the first randomized control trial of this straightforward method. Such an approach holds promise for enhancing language capabilities in infants born too early.

Premature birth often leads to changes in brain anatomy, raising the likelihood of language obstacles that can hinder subsequent communication skills and academic performance. A mother’s voice and heartbeat are known to promote the development of the pathways connected to hearing and language abilities. However, it is not always feasible for parents to be present with or hold their infants in a neonatal setting.

To investigate whether a recording could replicate a parent’s presence, Katherine Travis from Weill Cornell Medicine in New York and her research team studied 46 premature infants born between 24 and 31 weeks of gestation in neonatal intensive care.

The mothers were asked to record themselves reading excerpts from the classic children’s book A Bear Called Paddington. Half of the infants had a 10-minute audio recording played for them twice every hour from 10 PM to 6 AM, adding about 2.7 hours of their mother’s voice exposure daily until they reached their expected due date. The remaining infants continued to receive the same care without any audio recordings.

After reaching term, the infants underwent two types of MRI scans to assess the organization and connections in their brain networks. Scans indicated that those who were exposed to their mother’s voice displayed stronger and better-organized connections within the left arcuate fasciculus, a key area involved in language processing. Travis noted, “Its structure has a more mature appearance, resembling that of an older or more developmentally advanced child.”

The imaging results also imply that this maturation may be linked to increased myelination, which involves forming fatty sheaths around nerve fibers that enhance the speed and efficiency of signaling within the brain. “Myelination plays a crucial role in healthy brain development, particularly in communication and learning-associated pathways,” explains Travis.

Previous research has connected developmental delays in these brain regions to future language and learning challenges. These new findings suggest that targeted auditory exposure might yield improvements in those areas.

Yet, the study does not clarify whether hearing the mother’s voice is uniquely beneficial compared to others. However, past investigations have shown that infants begin to perceive sounds around 24 weeks gestation, and constant exposure to their mother’s voice while in utero is believed to explain why they prefer it once born. “It’s the most familiar and biologically meaningful voice for a baby,” states Travis. “Given this voice’s well-established presence even before birth, it may particularly engage the developing brain.”

Despite this, speech variability is also crucial for language development, suggesting that interactions from other caregivers might offer similar advantages. The research team plans to investigate this concept in forthcoming studies.

This straightforward intervention could be seamlessly integrated into caregiving practices. However, David Edwards from Evelina London Children’s Hospital cautions against overinterpreting the results. “The sample size is quite small, and additional control groups—incorporating other speech sources, diverse auditory stimulations, and alternative forms of engagement—are needed,” he remarks.

Travis and her colleagues aim to validate these findings in larger-scale trials and with infants facing more severe medical challenges. They will also continue to monitor the initial participants to determine whether the observed brain differences translate into tangible benefits for language and communication as the children mature.