The linguistic benefits of talking to babies has been well documented, as their brains rapidly develop, allowing them to make millions of new connections. Now, researchers looking at the effects of adult speech on preterm infants have found that increased adult speech during the early weeks of life is associated with better cognitive scores later.
Results of the study are published in Pediatrics, the journal of the American Academy of Pediatrics.
The study authors note that older children exposed to little amounts of adult speech are at risk for delays in language development, but it had not yet been established whether the same was true for preterm babies.
According to the Child Welfare Information Gateway, a division of the US Department of Health & Human Services, connections in the brain - called synapses - develop at a swift rate in a child's early years.
In fact, at the pinnacle of development, the cerebral cortex of a small child can create 2 million synapses per second.
As such, the researchers theorized that preterm babies who were exposed to higher word counts would have better cognitive and language scores at 7 and 18 months old.
To test their theory, the team recorded 16 hours of adult speech and sounds from 36 preterm infants with a birth weight less than or equal to 1,250 g (2.75 lbs) in the neonatal intensive care unit (NICU) at Women & Infants Hospital in Rhode Island.
Higher word count, higher communication scores
Using a Language Environment Analysis recording device, the investigators recorded adults talking to these infants at 32 weeks old and again at 36 weeks.
Preterm infants who were exposed to more adult speech in the NICU scored higher in language and communication scores at 7 and 18 months of age.
When the babies were 18 months old, the researchers observed that for every increase of 100 adult words spoken per hour at 32 weeks, the infants displayed a 2-point increase in language composite scores and a 0.5-point increase in expressive communication scores.
Additionally, the study authors found that for every increase of 100 adult words per hour at 36 weeks, the infants showed a 1.2-point increase in the Bayley Cognitive Composite at 7 months old.
The Bayley Cognitive Composite is a combined score for a set of measurements that assess motor, language and cognitive development in infants up to the age of 3.
At just 7 months of age, total adult word count for all recordings was linked to overall higher cognitive, language and receptive communication scores in the infants, and at 18 months, it was linked to higher expressive communication scores.
The study authors say their results show that preterm infants in the NICU benefit from exposure to adult speech, adding:
"These findings offer an opportunity for language intervention starting in the NICU."
In early 2013, Medical News Today reported on a study that suggested babies start learning language in the womb, implying vowel sounds in the mother's speech are picked up by the fetus.