What Do Babies Really Hear In There?

It is well known that unborn babies can recognize their mothers' voices and distinguish music from noise. But exactly what they hear remains unclear. Now, scientists at the University of Florida have added a piece to th
It is well known that unborn babies can recognize their mothers' voices and distinguish music from noise. But exactly what they hear remains unclear. Now, scientists at the University of Florida have added a piece to the puzzle.
What do they hear?
In a series of unique experiments on a pregnant ewe designed to record exactly what sounds reach the fetal ear, UF research has bolstered previous findings suggesting that human fetuses likely hear mostly low-frequency rather than high-frequency sounds. That means they hear vowels rather than consonants and are more sensitive to the melodic parts of speech than to pitch, says Ken Gerhardt, a UF professor of communication sciences and disorders and an associate dean of the Graduate School.

As for music, "they're not going to hear the violins, but they will hear the drums," says Gerhardt, who led the research reported in the November-December 2003 issue of the journal Audiology and Neuro Otology.

Anthony DeCasper, a professor of developmental psychology at the University of North Carolina-Greensboro, says the UF results are noteworthy because they were obtained from the inner ear, which presumably would register sounds exactly as a sheep fetus would hear them. The findings -- which resulted from implanting a tiny electronic device in the inner ear of a fetal sheep that tapped into the signal the ear sends to the brain -- dovetail with what other researchers have concluded based on less invasive studies involving human fetuses, he says.

"The way I put it is, the way the mother's voice would sound in utero would be like Lauren Bacall speaking from behind a heavy curtain," DeCasper says.

Implications for preemie care
The research also may have implications for the care of premature babies. Neonatal care units are traditionally relatively noisy places, replete with beeping machines and the hum of conversation, and research by Gerhardt, DeCasper and others is raising awareness and questions about how the sounds "preemies" are exposed to may influence normal growth and development, researchers say.

Gerhardt said he began researching fetal hearing in response to inquiries from law enforcement agencies and the US Navy. Both were concerned about how loud noises, such as gunfire or the rumble of a ship's engine, could affect the hearing of babies being carried by pregnant servicewomen.

Gerhardt and Robert Abrams, a UF professor emeritus of obstetrics and gynecology, decided to study the issue using sheep because experiments by other researchers had shown that properties of sound transmission in pregnant women and sheep are similar. Their experiments revealed the womb dampened all but the loudest sounds. Even loud rock concerts are probably not noisy enough to pose a threat to fetal hearing development, Gerhardt says. The research, which has received more than $1 million from the Navy, the National Institutes of Health and the March of Dimes, contributed to federal workplace safety guidelines that today limit the duration of extremely loud noise exposure for pregnant women.

In their recently reported research, Gerhardt and Abrams focused specifically on the kinds of sounds fetal sheep hear. Their method was unique: They implanted an electronic "pickup" inside the inner ear of a fetal sheep, then played 64 recorded sentences on a loudspeaker in the open air near the mother sheep. The sounds the pickups detected were recorded and played back to 30 human adult listeners in order to determine how much or what portions of the sentences the fetus actually heard. For comparison, the researchers also placed a microphone inside the uterus of the ewe and in the open air, then performed identical tests with human listeners.

The results were surprising, with the intelligibility of sentences "actually much higher than we anticipated," Gerhardt says.

In part, that was unexpected because much of the noise that reaches a fetus comes from its mother's own voice, movement, breathing and digestive processes. Even in a quiet room, the womb can be noisy place, he said. Also, fetuses don't "hear" as much with their ears as children or adults do because their ears are filled with fluid, he said. Rather, much noise is transmitted to their inner ears through vibrations in their skulls. As a result, the mother's voice tends to be the most dominant and recurring sound in the womb.

The listeners understood all of the sentences recorded in the open air, about 70 percent of the sentences recorded in the womb and about 30 percent of the sentences recorded in the fetal sheep's inner ear.

The recordings revealed the reason the inner ear-recorded sentences proved so much less intelligible was that the higher-frequency consonants in words tended to be absent or confused. In other words, "ship" could easily be heard as "slit" or "sit."

Lower-frequency vowels, by contrast, tended to penetrate the inner ear to a much greater extent.

Charlene Krueger, a UF assistant professor of nursing who works with premature babies, said that while a fetus hears its mother's voice whenever she speaks and is insulated from higher frequencies, infants born prematurely don't hear their mother's voices all the time because their mothers usually can't be at the bedside 24 hours a day.

Also, while unborn children are insulated from many frequencies, preemies are exposed to all the frequencies of the sounds in the nursery. She is interested in finding out how this added exposure, combined with the loss of the mother's voice, might influence the preemies' development. PregnancyAndBaby.com

Tags: hearing sounds womb

recommended for you


carpinteyroimv November 14, 2014
锘縮 his particular start-up into the eatery home business, your The state of texas united states inspired The country.The actual Fortification Worth centered Environment friendly and also restauranteurs Free Range Aspects exposed The country around uptown Facilities, at the intersection regarding Of lemon Avenue and also Northern Key<a href=http://www.vakantieplaats.nl/application/language/template2.php?moncler-down-jacket-women-hooded-jackets-deep-1739-p-282.html>Moncler Down Jacket Women hooded Jackets Deep 1739 Lage Prijs Verkoop Winkel 2014</a> Expressway, beginning past drop."It's doing gangbusters, a great deal better than I personally <a href=http://rhand.org.tt/Uploads/nike/nike15471.html>nike air max thea womens sale</a>ever believed it had become likely to conduct," he was quoted saying. "It's what we say: location, spot, position and I found myself in it all by using males who believed what they have to did."Green with his fantastic wife Kori were living during Fortin Well worth going back nine many years the actual Washington created Texan sees himself making outside more of their time to a family event, together with Ten year ancient boy Kellis and seven years old little princess Rianey.閿樼笅at Environment friendly to title telethon Wednesday

Practically some yrs ago, Terry Green's "Wave about Wave" risen on the country music charts, making the Tx popular music musician on the Absolutely no. Three right the national index charts. For your young performer out of San Antonio, that it was a good heady knowledge.<a href=http://rhand.org.tt/Uploads/nike/nike20063.html>nike air max 2014 size 9.5</a>

"I was initially brimming with myself personally," he said inside a telephone meeting through his / her Fortin Really worth home. "I ended up being fresh, and this was this first legitimate being successful on the stereo. I'd never had music about the broadcast to get Thirty seven days.In

Green headers free The state of texas Therapist Center's Telethon the following Sunday overnight.

Natural provides expert more than a few objectives because her memorable visual appeal over the countrywide stock chart. He or she brilliant girl made welcome its kid five years ago and their little princess a couple of years afterwards. Eco-friendly recently adjusted trademarks in addition to document providers.

"Before, I'm a greater portion of wing it, permit if fly on an airline fellow,In he stated. "It became a great time, these days I am just aimed at allowing it to be better. We have usually was living inside second. Something I'm keen on in relation to warring is definitely I don't stay in yesteryear, I'm not really dreaming of the longer term. My bills get money by way of myself enjoying my personal classical guitar this is genuinely great.Half inch

While lifted with The state of texas, new bands wasn't generally his / her element. It was not before immediately after high school, as he evolved into accustomed to Tx artists for example Scott Earl Keene and also Jerry Jeff Walker. Music and songs stories Willie Nelson,

<a href=http://www.vakantieplaats.nl/application/language/template2.php?nieuw-2012-moncler-dames-kaki-sjaal-stijl-jassen-p-906.html>Nieuw 2012 Moncler Dames kaki sjaal stijl Jassen Lage Prijs Verkoop Winkel 2014</a>
<a href=http://rhand.org.tt/Uploads/nike/nike15974.html>nike air max all black suede</a>
<a href=http://rhand.org.tt/Uploads/nike/nike19600.html>nike free 3.0 v5 for sale</a>
<a href=http://rhand.org.tt/Uploads/nike/nike15300.html>nike air max 2014 mens trainers</a>
<a href=http://rhand.org.tt/Uploads/nike/nike23780.html>air jordan fusion 4 all black</a>
timberland アウトレット September 23, 2014
take some stress off of yourself and have a professional move your car for you to your new location. Make your move easier with an auto moving company!|||If you enjoyed this article by Maureen Romensya on car transport quotes check out our website today. We offer free auto transport quotes and car shipping without a scratch. Compare services & save. Hire an experienced car transport mover here.
[url=http://www.jrecksubs.com/scsm/timberland-shoes-57.html]timberland &#12450;&#12454;&#12488;&#12524;&#12483;&#12488;[/url]