With a biology degree and two boys who are young musicians, Leah has researched the developmental advantages of music for young children.
Why Do They Test a Newborn's Hearing?
The sense of hearing is well-developed at birth. Babies can hear in the womb, and their brains begin organizing centers for listening and speech from a very early age. Babies and young children need access to sound to develop listening and speaking skills.
In the United States, the Newborn Hearing Screening program was implemented to screen every baby prior to discharge from the hospital. Children who are at risk of hearing loss are identified through this program. If a hearing problem is identified, the child is referred for more thorough testing.
Children who are born at home or in a hospital that does not provide a newborn hearing screening test should have their hearing tested as soon as possible. Most hospitals and doctor's offices are able to test babies' ears with a simple otoacoustic emissions test or an automated auditory brainstem response test.
Early Detection Is Vital
While the incidence of a significant congenital hearing problem is only 3 in 1000, the benefits of early amplification and intervention are high. With the advent of digital hearing aids and cochlear implants, many profoundly deaf children are able to listen, speak, and sing if provided with early access to sound.
The Newborn Hearing Screening Explained: OAE and aABR
Two forms of testing are performed for the Newborn Hearing Screening Program. The first type of test is called the Otoacoustic Emissions test, or OAE. The other screening test method is the Automated Auditory Brainstem Response test, or aABR.
Otoacoustic Emissions (OAE)
When the ear hears a sound, a healthy inner ear (cochlea) will send back an echo of that sound. The echo sound is called an otoacoustic emission, and there is a simple screening test which detects the production of OAEs. Children who do not produce OAEs are referred for further testing.
Automated Auditory Brainstem Response (aABR)
The auditory center of the brain is located in the brainstem, and simple EEG leads can detect brainwaves indicating a sound was detected by the brain. Typically, "clicks" are presented to each ear at a sound level of 35dB (the sound level of a very soft conversation). If the baby indicates a response to that sound, then the test is scored as a "pass." If the baby does not show a reaction to the sound, the baby is referred for more testing.
What Does a "Refer Result" Mean?
Both the ABR and OAE tests are affected by obstructions in the outer or middle ear, so if a baby has a lot of vernix, earwax, or fluid in the ear, a "refer" may be scored. Many babies who refer on the initial newborn hearing screening test will be re-tested after a couple of weeks to determine if the initial result was due to temporary fluid or vernix.
My Baby "Referred" on the Follow-Up Hearing Screening Test: Is My Baby Deaf?
The hearing screening tests do not diagnose a hearing problem. If an infant refers on a second screening test, the baby is sent for more definitive diagnostic testing. It is absolutely vital to obtain diagnostic testing if a baby refers on a second screening test, as the baby is now "at risk" for having a hearing problem.
The hearing screening test should not be performed more than twice, as it is possible to obtain a false "pass" on the test for children with mild hearing loss. If an infant refers on the newborn hearing screening test, then a follow-up with a pediatric audiologist and ear, nose, and throat doctor (ENT) are necessary.
In addition, there are many levels of congenital hearing loss. The newborn hearing screening program is designed to detect moderate or greater hearing deficits in babies. Some children with mild hearing loss may escape detection, and children with moderate hearing deficits will appear to "hear" (startling at loud noises, for example) when a real hearing problem is present. It is impossible to tell if a baby can hear simply by observation, so getting a full diagnostic evaluation is vital.
What If a Baby Passes the Test But Does Not Hear?
Occasionally, an infant will pass the newborn hearing screening test but a hearing problem will be found months (or years) later. While the newborn hearing screening test is an excellent screening device, it often misses slight to mild hearing deficits. In addition, the program will not detect progressive hearing losses in children who had normal hearing at birth.
The "click" sounds produced in the newborn's ears are often a broadband high-frequency sound. For this reason, babies who have a low-frequency hearing loss (but normal hearing in the high frequencies) may be missed by the newborn hearing screening program. In addition, many children with mild hearing deficits or low-frequency hearing loss have present OAEs.
Auditory Neuropathy or Dyssynchrony
In hospitals that test via the OAE method, children with a condition called auditory neuropathy or dissynchrony are often not detected. Auditory dissynchrony is a hearing loss caused by a faulty relay of information along the auditory nerve. The inner ear is healthy, but the baby has difficulty hearing. Infants who have very high bilirubin counts (extreme jaundice), are in the Neonatal Intensive Care Unit (NICU) after birth, or are premature should have aABR testing performed alongside OAE testing.
A "two stage" screening approach has been recommended by many researchers. The two-stage screening process would include both the OAE testing and the aABR testing to detect children with auditory dyssynchrony and reverse-slope hearing losses. Currently, however, most hospitals employ only one screening method.
Some Hearing Deficits Are Hereditary
Some forms of hearing loss are genetic, while others have environmental causes.
What If We Don't Have Hearing Deficits in Our Family?
Parents may be shocked when told their baby might have a hearing loss. While some families have a pattern of hearing loss among close relatives, over 90% of infants with congenital hearing loss are born to parents with normal hearing.
What Are the Causes of Congenital Hearing Loss?
Congenital hearing loss can be caused by genetics or may be acquired.
- Over 50% of hearing loss is caused by genetic factors, with the most common genetic cause being a change in the GJB2 gene (connexin 26, a recessive trait).
- Non-genetic hearing loss may be caused by congenital cytomegalovirus (CMV), prematurity, lack of oxygen at birth, exposure to gentamicin (an antibiotic), and more.
- Approximately 25% of the time, the cause of congenital hearing loss cannot be found, and the condition is termed "idiopathic congenital hearing loss."
Identification and Treatment
In some cases, a congenital conductive hearing loss will be identified. This type of hearing loss is potentially correctable, depending on the cause. A conductive hearing loss caused by fluid in the middle ear may be treated with tympanostomy tubes (ear tubes) to restore the child's hearing to normal levels. A conductive hearing loss caused by middle ear bone malformations may be treated with surgery.
What Are the Risk Factors of Hearing Loss?
Risk Factors: 0-28 Days Old
- Family history of hereditary childhood sensorineural hearing loss
- Ototoxic medications
- Bacterial meningitis
- Birth weight less than 1500 grams (3.3lbs)
- In utero infections (cytomegalovirus, rubella, syphilis, herpes, and toxoplasmosis)
- Craniofacial anomalies (including the outer ear and ear canal)
- Apgar scores of 0-4 at 1 minute or 0-6 at 5 minutes
- Mechanical ventilation lasting five days or longer
- Findings associated with a syndrome known to include a sensorineural and/or conductive hearing loss
Risk Factors: >28 Days Old
- Neurofibromatosis Type II
- Neurodegenerative disorders
- Recurrent or persistent otitis media with effusion
- Anatomic deformities and other disorders that affect eustachian tube function
- In utero infection (e.g. cytomegalovirus)
- Family history of hereditary childhood hearing loss
Signs of Hearing Problems in Young Children
- Difficulty hearing some sounds, but not others
- Tilting the head when listening
- Speech delay or garbled speech
- Asks for instructions to be repeated
- Doesn't acknowledge the presence of others until they are within visual range
- Withdrawn behavior
- Frustration and frequent acting out
- Balance issues: may be slow to walk or stand
This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.
Leah Lefler (author) from Western New York on July 05, 2012:
Zaymom, firstly I am sending you a lot of hugs. Secondly, it is possible for a child to have a hearing loss with normal OAE. My son actually had OAE when he failed his newborn hearing test, because our hospital ran a test called an ABR. Has your beautiful boy had an ABR hearing test? The OAE screenings run by the hospitals are NOT a full hearing test, and generally only screen the highest frequencies. My son had a low frequency hearing loss at birth and if the hospital had run an OAE, he would have passed (he needs hearing aids to hear correctly, so this would have been a problem).
There are two hearing losses that get "missed" by the newborn hearing screen, particularly when OAE are used. The first is low frequency hearing losses, like my son had at birth, and the second type of hearing loss is auditory neuropathy or auditory dyssynchrony (ANSD). Children with ANSD have normal OAE because the hair cells in the cochlea are normal. The auditory nerve, however, has difficulty conveying the information to the brain - these children sometimes benefit from hearing aids, but a cochlear implant is generally more useful (this is completely dependent on the child).
The only way to really rule out a hearing loss is to have a complete audiologic evaluation, and at his age behavioral measures can be used. I hope the audiologist is able to give you a diagnosis for your little one, so you can get treatment for him. It is possible to have present OAE and still have a hearing loss!
zaymom on July 04, 2012:
Great article. very useful information.
I am a desperate mom.
We have 1 year baby boy , whose hearing has been tested at Birth, 3 months and 6 Months and have been said everything is Perfect. He is healthy and happy boy. Started walking at 10 months and look at the book, play with Toys and watch Rhymes. He is very quite and happy always. He laugh and respond when we make an eye contact. He even enjoy teh Peek-a-boo when we do that in front of him. He has a favourite toy making a noice, but we surprised he can't understand if that make a noice just behind him. However he can't hear anything we say from his backside.
We took him to the hear screening yesterday, they did the OAE Test and said his hearing is perfect.
But we know he is not able to hear anything. He dont repeat what we say , but blabber at least 4-5 sounds countinously. We don't have any hearing problem history in our families. Is anybody know any case that OAE passes but can't hear.or kids not responding till some age and then did. (I know this can't be the case, but still hoping)
We are planning to take him to the Audiologist.
I know I have to be brave but can't stop crying.
Leah Lefler (author) from Western New York on May 05, 2011:
Thank you, Mandeeadair. I hope someone find the information useful - particularly parents who are navigating the waters of a "referred" newborn hearing screen!
Mandeeadair from California on January 27, 2011:
Great hub! Useful information. :)
Leah Lefler (author) from Western New York on January 25, 2011:
Thank you, Pamela! My little guy's name is Nolan (akircher's son is named Pat).
Pamela Oglesby from Sunny Florida on January 25, 2011:
This is an excellent article and Pat is adorable. Congrats on your nomination.
RTalloni on January 25, 2011:
Informative an well done. Welcome to HP.
Leah Lefler (author) from Western New York on January 23, 2011:
Thank you for the compliment (and the advice)! I deeply appreciate your help, Shadesbreath!
Shadesbreath from California on January 23, 2011:
Very informative and nicely written work. That otoacoustic emission technology is very cool. See, this hub counts as one of those "I learned something new today" moments for me, which I greatly value. Thanks.
Leah Lefler (author) from Western New York on January 22, 2011:
Ripplemaker, sometimes babies don't get tested (due to a hospital error or a very rural location). Also, some babies pass the newborn hearing test and then develop a hearing loss later on: they have a progressive hearing loss. The newborn hearing screen aims to find children with moderate or greater losses, so kids with mild losses will also be missed by this test. We were fortunate that our little boy "referred" on the hearing screen, because he was just at the cut-off for what they test for.
Parents should definitely have an older child tested if they suspect an issue: no matter what communication mode the parent chooses, the child has more access to language with early intervention!
Louise Phillips on January 21, 2011:
Well written and informative. Very useful for parents looking for answers to their babies' hearing problems.
Michelle Simtoco from Cebu, Philippines on January 21, 2011:
A parent brought to our school a child who has a hearing problem. I don't know if our hospitals has this type of tests done on newborns. I think they just observed that he had hearing problems later on. Definitely a helpful tool for screening! Thanks for this explanation.
Hubnuggets Flash: This hub is a Hubnuggets nominee. We invite everyone to please read the nominated hubs and vote! You have the right to vote...hubbers and non hubbers alike! So what are you waiting for? Follow me right here: http://bit.ly/eb4vTx
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Audrey Kirchner from Washington on January 12, 2011:
Leah - Thanks so much for visiting my hub and what an ADORABLE child!
I always think I got Pat for a reason and it's been such a ride. At 32 (good lord that makes me like 42....I wish), I still continue to marvel at who he is and all that he's done.
Welcome to Hubpages and bless little Nolan - you sound like you know what to do....love and guide him and that's all he'll need to become (more) wonderful.
I always look at Pat as a gift because I learned so much about life, about myself and what things we take for granted sometimes...and also about different ways to see things - literally. You're probably an expert on how to hear things better!
Anyhow - keep in touch and wishing you the joy of a lifetime that I've had with my kids but especially with Pat. He did teach me so very much and still does!