Overview of the Findings
A Stanford Medicine–led study published online October 13 in Frontiers in Human Neuroscience provides the first randomized evidence that exposure to a mother’s voice can promote language development in very premature infants. The research found that regular recordings of mothers reading to their hospitalized preemies helped advance the maturation of a key language pathway in the brain, as observed by MRI scans at discharge.
The Study in Context
Premature babies—born at least three weeks early—often face longer hospital stays and reduced exposure to the sounds of speech compared with in utero development. This reduced early-life speech exposure has long been linked to later language delays. The Stanford team aimed to determine whether augmenting the auditory environment with maternal speech could influence brain development during a critical window of early life.
Methods and Intervention
The trial enrolled 46 very premature infants who had stabilized from acute care and were in intermediate care nurseries before potential discharge. Infants were randomly assigned to two groups: a treatment group that heard recordings of their mothers reading a chapter of Paddington Bear in the mothers’ native languages, and a control group that did not hear the recordings.
The mother’s voice recordings were played at night, 10-minute segments, totaling 160 minutes per day across several weeks. This timing minimized potential parental bias or influence on outcomes, as parents and hospital staff remained unaware of the group assignments. The recordings were designed to resemble in utero auditory experiences as closely as feasible under hospital conditions.
What the Researchers Measured
At the end of the intervention, researchers performed MRI scans focusing on the arcuate fasciculus—two major white-matter tracts linked to language processing, with the left tract typically more specialized for language. The key finding was that the left arcuate fasciculus showed greater maturation in the treatment group compared with controls. The right hemisphere tract showed less pronounced changes, aligning with known lateralization patterns in speech processing.
Interpretation and Implications
Lead author Katherine Travis, PhD, noted that this study provides the first causal link between a specific speech experience and very early brain development. “This is the first causal evidence that a speech experience is contributing to brain development at this very young age,” she said. Senior author Heidi Feldman, MD, PhD, highlighted the potential of the approach to transform neonatal care practices aimed at improving future language outcomes for children born prematurely.
What’s Next
The team plans follow-up studies to determine whether benefits extend to preterm infants with medical complications and to explore the mechanisms by which voice exposure influences neural pathways. Clinicians like Melissa Scala, MD, emphasize that even brief, targeted auditory exposure can complement in-person parental interaction. In addition, efforts are underway to tailor hospital soundscapes so the sounds preemies hear most closely mimic a healthy intrauterine environment.
Parental and Clinical Takeaways
For families, the findings offer reassurance that maternal involvement—even when physically present is limited—can support brain development. While in-person bonding remains essential, recordings of a mother’s voice could serve as a practical supplement that bolsters early-language circuitry during a vulnerable period. Neonatal teams are increasingly considering individualized auditory plans that balance medical needs with natural language exposure to optimize developmental trajectories.
Funding and Acknowledgments
The research was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (grants 5R00-HD84749 and 2R01-HD069150). The study represents a collaborative effort among Stanford Medicine researchers and aligns with a growing body of work on how early sound environments shape neural development.
