Infants benefit from implants with more frequency sounds

May 19, 2014
A UT Dallas researcher studied how 6-month-olds distinguished between speech sounds. Through cochlear implant simulations, she found that infants process speech differently than older children and adults.

(Medical Xpress)—A new study from a UT Dallas researcher demonstrates the importance of considering developmental differences when creating programs for cochlear implants in infants.

Dr. Andrea Warner-Czyz, assistant professor in the School of Behavioral and Brain Sciences, recently published the research in the Journal of the Acoustical Society of America.

"This is the first study to show that infants process degraded speech that simulates a cochlear implant differently than and adults, which begs for new signal processing strategies to optimize the sound delivered to the cochlear implant for these young infants," Warner-Czyz said.

Cochlear implants, which are surgically placed in the inner ear, provide the ability to hear for some people with severe to profound hearing loss. Because of technological and biological limitations, people with hear differently than those with normal hearing.

Think of a piano, which typically has 88 keys with each representing a note. The technology in a cochlear implant can't play every key, but instead breaks them into groups, or channels. For example, a cochlear implant with 22 channels would put four notes into each group. If any keys within a group are played, all four notes are activated. Although the general frequency can be heard, the fine detail of the individual notes is lost.

Two of the major components necessary for understanding speech are the rhythm and the frequencies of the sound. Timing remains fairly accurate in cochlear implants, but some frequencies disappear as they are grouped.

More than eight or nine channels do not necessarily improve the hearing of speech in adults. This study is one of the first to examine how this signal degradation affects hearing speech in infants.

Infants pay greater attention to new sounds, so researchers compared how long a group of 6-month-olds focused on a speech sound they were familiarized with —"tea"'—to a new speech sound, "ta."

The infants spent more time paying attention to "ta," demonstrating they could hear the difference between the two. Researchers repeated the experiment with speech sounds that were altered to sound as if they had been processed by a 16- or 32-channel cochlear implant.

The infants responded to the sounds that imitated a 32-channel implant the same as when they heard the normal sounds. But the infants did not show a difference with the sounds that imitated a 16-channel implant.

"These results suggest that 6-month-old need less distortion and more frequency information than older children and adults to discriminate speech," Warner-Czyz said. "Infants are not just little versions of children or adults. They do not have the experience with listening or language to fill in the gaps, so they need more complete information to maximize their communication outcomes."

Clinicians need to consider these developmental differences when working with very young cochlear implant recipients, Warner-Czyz said.

Explore further: New strategy lets cochlear implant users hear music

More information: "Vowel discrimination by hearing infants as a function of number of spectral channels," Andrea D. Warner-Czyz. J. Acoust. Soc. Am. 135, 3017 (2014); dx.doi.org/10.1121/1.4870700

Related Stories

New strategy lets cochlear implant users hear music

October 9, 2013
For many, music is a universal language that unites people when words cannot. But for those who use cochlear implants—technology that allows deaf and hard of hearing people to comprehend speech—hearing music remains extremely ...

Imbalanced hearing is more than a mild disability

March 12, 2014
Researchers at Washington University School of Medicine in St. Louis have received a five-year, $3 million grant from the National Institutes of Health (NIH) to study the effects of asymmetric hearing loss in adults and children.

Two bionic ears are better than the sum of their parts

September 20, 2012
Cochlear implants—electronic devices surgically implanted in the ear to help provide a sense of sound—have been successfully used since the late 1980's. But questions remain as to whether bilateral cochlear implants, ...

Researchers seek to improve listening with cochlear implants, hearing aids

March 28, 2014
(Medical Xpress)—Over the past two decades, people living with severe-to-profound hearing loss have benefited from cochlear implants—surgically implanted electronic devices that provide a sense of sound. More recently, ...

Design prototype chip makes possible a fully implantable cochlear implant

February 10, 2014
Researchers from Massachusetts Eye and Ear, Harvard Medical School, and Massachusetts Institute of Technology (MIT) have designed a prototype system-on-chip (SoC) that could make possible a fully implanted cochlear implant. ...

Recommended for you

At the cellular level, a child's loss of a father is associated with increased stress

July 18, 2017
The absence of a father—due to incarceration, death, separation or divorce—has adverse physical and behavioral consequences for a growing child. But little is known about the biological processes that underlie this link ...

New comparison chart sheds light on babies' tears

July 10, 2017
A chart that enables parents and clinicians to calculate if a baby is crying more than it should in the first three months of its life has been created by a Kingston University London researcher, following a study of colic ...

Blood of SIDS infants contains high levels of serotonin

July 3, 2017
Blood samples from infants who died of Sudden Infant Death Syndrome (SIDS) had high levels of serotonin, a chemical that carries signals along and between nerves, according to a study funded in part by the National Institutes ...

Is your child's 'penicillin allergy' real?

July 3, 2017
(HealthDay)—Many children suspected of being allergic to the inexpensive, first-line antibiotic penicillin actually aren't, new research indicates.

Probiotic supplements failed to prevent babies' infections

July 3, 2017
(HealthDay)—Probiotic supplements may not protect babies from catching colds or stomach bugs in day care, a new clinical trial suggests.

Starting school young can put child wellbeing at risk

June 22, 2017
New research has shown that the youngest pupils in each school year group could be at risk of worse mental health than their older classmates.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.