Even tiny premature babies in hospital care after birth can make baby sounds, and are especially vocal when their parents are talking to them -- a finding that could be significant in terms of later language ability, a U.S. study said.
Very premature babies are known to be slower-than-average in picking up language skills. It is also not known whether the sounds they hear soon after birth are related to later language development.
But infants in the neonatal intensive care unit (NICU) of a hospital are in are in a very different sound environment from the womb, where their mother`s voice is the most prominent sound, said Melinda Caskey, a pediatrician at Women and Infants Hospital in Providence, Rhode Island.
In the hospital, the beeps and whirs of medical equipment abounded, Caskey and her team found in their study of nearly 40 infants, with surprisingly little language heard.
"It`s very striking, especially when you compare that with what the fetus hears," she told Reuters Health of the study, published in the journal Pediatrics. It is the first to look at how much language NICU preemies hear during the day.
When preemies were hearing adults talk -- their parents especially -- they were more vocal themselves, which usually meant making short vowel sounds.
The significance of those vocalisations was not yet clear. Caskey, the study`s lead researcher, and her colleagues were following the infants to see if their NICU language exposure was related to language development later on -- and possibly change how the infants are handled if that was the case.
"We`d want both parents and nurses to talk to the infants more in their daily interactions," she said.
The study looked at 36 very preterm infants -- born, on average, during the 27th week of pregnancy. Pregnancy normally lasts around 40 weeks.
The researchers outfitted each baby with a vest that carried a digital recording device. The recorder captured environmental sounds and the infants` vocalisations over two 16-hour periods -- at what would have been the 32nd and 36th weeks of pregnancy.
They found that the babies were already able to make vocalisations at week 32. Vocalisations rose by as much as 129 percent when parents were visiting.
The babies also showed more "conversational turns" -- when their vocalisations came within seconds of the parent speaking.
At week 32, the infants were also more vocal when their parents, rather than a nurse, were feeding them.
Overall language accounted for only two percent to five percent of the total recorded sounds, Caskey`s team found.
While the study focused on a single NICU, Caskey said the environment of many other NICUs was likely to be the same.