New Evidence Links Maternal Speech to Brain M development in Premature Infants
Hearing the sound of a mother’s voice can shape the developing brains of premature babies, according to a Stanford Medicine-led study. The randomized trial, published online in Frontiers in Human Neuroscience, found that regular exposure to recordings of mothers reading to their hospitalized preemies led to greater maturation of a key language pathway in the brain.
The Study at a Glance
In what researchers describe as the first randomized controlled trial of its kind for early development, 46 very premature infants were enrolled after they became medically stable enough to leave the NICU for a more intermediate care setting. The babies were randomly assigned to receive either recordings of their mothers reading a Paddington Bear chapter (in the mother’s native language) or standard care without the recordings.
For the intervention group, mothers’ voices were played during the night for 10-minute segments, totaling 160 minutes nightly over several weeks. Parents did not know which group their baby belonged to, helping ensure that maternal behavior did not bias results. MRI scans performed before discharge revealed notable differences in the brain’s language circuitry.
Key Finding: Maturation of the Left Arcuate Fasciculus
Researchers focused on the arcuate fasciculus, a major white-matter tract implicated in language processing. The left arcuate fasciculus showed significantly greater maturation in the treatment group compared with controls. The right-side tract showed fewer changes, aligning with established hemispheric differences in speech processing.
Lead author Katherine Travis, PhD, commented that the findings provide causal evidence that a speech experience can influence brain development in the very early neonatal period. “This is a potentially transformative way of thinking about how to approach neonatal care for promoting better language outcomes in children born prematurely,” she noted. Senior author Heidi Feldman, MD, PhD, added that the results demonstrate a real, early-life brain impact from a modest, targeted intervention.
Why This Matters for Preemies
Premature infants often have limited exposure to maternal speech after birth, due in part to the practical realities of hospital care and parental availability. In utero, fetuses begin hearing around 24 weeks and, as term approaches, become increasingly responsive to their mother’s voice and native language. The study suggests that supplementing hospital soundscapes with maternal speech can partially compensate for reduced early auditory stimulation and potentially support language development trajectories.
Participants and Methods
The 46 very preterm babies were all born more than eight weeks early and lacked major congenital anomalies or significant postnatal complications. After hospital discharge planning began, researchers randomly assigned them to the listening or control groups. The recorded sessions—read aloud by mothers in their own language—were designed to mirror the kind of auditory environment a fetus would hear in the womb, adapted for the NICU setting.
Neuroimaging, including MRI assessments of the arcuate fasciculus both left and right hemispheres, served as the primary outcome measure. The results persisted beyond the immediate postnatal period, underscoring the potential lasting impact on language pathways.
Implications for Families and Care
Parents of preemies often face stress and anxiety during prolonged hospital stays. Clinicians emphasize that in-person bonding remains crucial, including skin-to-skin contact and responsive care. This study offers a complementary approach: even when parents cannot be present round the clock, voice recordings can maintain essential auditory contact and contribute to brain development.
The researchers plan follow-up studies to determine whether benefits extend to babies with medical complications and to unpack how voice recordings exert their effects. Clinicians at Packard Children’s are already developing customized sound plans to optimize NICU environments for neurodevelopment.
Support and Acknowledgments
The research was supported by grants from the Eunice Kennedy Shriver National Institute of Child Health and Human Development. The team emphasizes that while the findings are promising, ongoing work is needed to translate them into widespread clinical practice and family guidance.
What Parents Can Take Away
Even when hospital visits are limited, preterm infants can benefit from hearing their mother’s voice. Clinicians encourage parents to engage in regular, comforting verbal interactions when possible, while recognizing that recorded speech may offer an important, supplementary tool to promote healthy language development.
