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Newborn Screening
What is Universal Newborn Hearing Screening (UNHS)?
Simple,
hearing
child is
hearing
inexpensive and safe tests are now available to check
in the first days of life. It is no longer necessary to wait until a
old enough to take a formal hearing test in order to check for
loss. Newborn hearing tests are important for families,
because much can be done if hearing loss is caught early in a
baby's life.
Hearing screening programs are called "universal" because the goal is to test all newborn babies.
This means that babies in both the regular and intensive care nurseries are screened before they
leave the hospital (or within 3 weeks of hospital discharge). Many people refer to screening
programs by the name Early Hearing Detection and Intervention (EHDI). This title is popular
because detecting a hearing loss is just the first step.
If a hearing loss is detected, the next step is intervention. Intervention may include hearing aids or
hearing devices, and services to support the family and baby in learning communication skills.
It is important for all babies to be screened, but not all babies are born in hospitals. Individual
states may have different requirements for babies who are born at home. Ideally, babies born at
home should be tested before they are two months old.
Newborn Screening
Why is Universal Newborn Hearing Screening Important?
You might be wondering why it's important to detect hearing loss so early. It is remarkable how
quickly babies start to learn language and speech. Listening in the first few months of life
prepares the baby to learn language.
By the first birthday, infants are already figuring out what words mean. Before their first birthdays,
they babble many of the sounds they hear spoken around them. These early steps are building
blocks for communication.
Babies learn language by tuning in to family talk. Now suppose a baby has a hearing loss and no
one finds this out. This can lead to slow development of speech and language. It can create
difficulties in family communication. Delays in speech and language can also lead to school
problems, both academic and social. Finding hearing loss early helps to prevent these delays.
Hospitals routinely screen babies for some specific problems, like PKU (PKU is an abbreviation
for Phenylketonuria. Children born with this rare genetic disorder cannot metabolize a part of
protein in food). Interestingly, hearing loss occurs more often in babies than any of the other
problems that are screened for at birth. Approximately one to three babies out of 1000 will be
born with permanent hearing loss. Because this represents an important public health concern,
many hospitals are participating in hearing screening programs.
Newborn Screening
How Does Newborn Hearing Screening Testing Work?
Currently there are two tests that hospitals and agencies use to screen babies for hearing loss.
Both of these tests are safe and comfortable. They pose no risks for babies.
One of
are
and a
hears
into the
hearing
the OAE test.
Otoacoustic Emissions
the tests is called otoacoustic
emissions or OAEs. For this test, a
miniature earphone and microphone
placed in the ear, sounds are played
response is measured. If a baby
normally, an echo is reflected back
ear canal and this is picked up by the
microphone. When a baby has a
loss, no echo can be measured on
Auditory Brainstem Response
The second test is called auditory brainstem response or ABR. For this test, sounds are played
to the baby's ears. Band-aid like electrodes that are placed on the baby's head detect
brainwaves. This test actually measures the brain responding to sounds. This test also identifies
babies who have a hearing loss.
The two test methods may be used individually or in combination. In some hospitals, babies are
first screened using OAEs, and the babies who do not pass this test are given the ABR test.
Both tests are accurate and reliable. Your hospital has selected a method based on hospital
resources, available personnel, cost, and the number of babies born in the hospital.
Newborn Screening
What Does it Mean if a Baby Fails the Newborn Hearing Screening Test?
When a baby does not pass the newborn hearing screening test, this does NOT necessarily
mean the baby has a hearing loss. Across the nation, between 20 to100 babies per 1000 (two-10
percent) do not pass the screening test. Only one to three babies per 1000 (less than 1 percent)
actually have hearing loss. This means that most of the babies referred for follow-up testing will
be shown to have normal hearing.
You may wonder why a baby with normal hearing would fail the newborn hearing-screening test.
There are several common reasons:
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Vernix in the ear canal
Fluid in the middle ear
Movement and/or crying during the test
Even though most babies will pass the follow-up hearing testing, it is VERY important to take your
baby for follow-up testing. This is the best way to be SURE about your baby's hearing.
Newborn Screening
Can a Baby Pass the Test and Still Have Hearing Loss?
Although it doesn't happen very often, sometimes babies can
pass a hearing test and still have hearing loss. Some mild hearing losses or losses that
affect only some pitches may not be picked up by the screening test.
Some infants have hearing loss that is not present at birth. These babies are born with
normal hearing, but develop a hearing loss after the newborn period. This condition may
result from certain illnesses or from some genetic causes.
Hearing loss after the newborn period might also happen because of the use of certain
medications or as a result of trauma or disease.
If your baby has risk factors for these types of hearing loss or if you have concerns about your
child's responses to sound or speech development, you should discuss this with your baby's
doctor.
It is important to keep in mind that regardless of your baby's age, there are safe, effective and
accurate tests that can be used to determine how well your baby hears.
Newborn Screening
What Should I Do If My Baby Fails the Test?
You should discuss the test results with your baby's doctor. The doctor will probably refer your
baby to a pediatric audiologist for further testing.
The First Step
In many cases, the first step will be a rescreen using techniques similar to those used in the
hospital. In other hospitals and clinics, a diagnostic Auditory Brainstem Response (ABR) test will
be done immediately. Recall that ABR was discussed previously, but that was a screening
version of the test. A diagnostic ABR is a more thorough test of the baby's hearing.
When we hear sounds, we recognize different pitches or tones. A piano keyboard has a range of
tones from low to high. Speech sounds we hear are also made up of a range of tones. The last
time your hearing was tested, you probably listened for soft tones that ranged from low to high
pitch. A diagnostic ABR is a test that will help determine how much hearing loss is present for
these different pitches of sound.
The goal of this test is to find the softest sounds that produce a response for low, middle, and
high pitched sounds.
If your baby is tested before 2 months of age, testing usually can be done while the baby is
sleeping naturally.
If your baby is older or very active, a liquid medicine may be used to make your baby sleepy. This
will ensure that the baby's movements do not interfere with the test.
If the baby passes the ABR test, no further testing is needed. However, babies should continue to
be watched for hearing loss that occurs after the newborn period.
The Second Step
If diagnostic testing shows that your baby has a hearing loss, a number of professionals
may become involved to help your baby and your family. Some of the people you may
meet include the following:
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Services Coordinator - this professional works with early intervention
programs. He or she works closely with the family to identify needs and to
ensure that providers work together and coordinate their efforts to make
intervention manageable for the family
 Infant/Family Specialist - a teacher who specializes in working with
infants who have hearing loss and their families
Pediatric Audiologist - a professional who specializes in testing the hearing of
infants and children and recommends hearing instruments
Ear, Nose and Throat Physician - a doctor who specializes in problems of the
ear, nose and throat
Pediatrician or Family Practitioner - a doctor who provides primary health care
for infants and children
If your baby has a hearing loss, these professionals will be eager to provide support to your
family. Their main goal will be to work together to limit the effects of the hearing loss on your
baby's development. It is essential that appropriate services begin as soon as a diagnosis of
hearing loss is made. The Joint Committee on Infant Hearing and the American Academy of
Pediatrics recommend that services should begin before 6 months of age if at all possible.
All About Hearing
Loss
How the Ear Works
The Ear is made up of three
parts:
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External Ear
Middle Ear
Inner Ear
The picture on the right shows
the three parts of the ear:
External Ear
Sounds travel through the external ear or ear canal and cause vibration of the
eardrum (tympanic membrane).
Middle Ear
Eardrum movement causes the three middle ear bones (ossicles) to vibrate.
This vibration creates movement of fluid in the inner ear (cochlea).
Inner Ear
The inner ear, or cochlea, sends nerve impulses to the brain. Once the brain
receives the message, we have a sensation of hearing.
The sound wave moves the eardrum
and attached ossicular chain. The
stapes footplate, in the round
window, transfers the vibrations to
the perilymphatic compartment
(scala vestibuli) and to the inner ear
structures. Depending on frequency,
the vibration has a maximum effect
(resonance) at a different point along
the basilar membrane, accounting for
passive tonotopy. Here on the left, a
high frequency sound effects a basal
portion of the cochlea.
Animated drawing by S Blatrix, from "Promenade around the cochlea ' by R Pujol, S. Blatrix, T. Pujol and V.
Reclar-Enjalbert, CRIC, University Montpellier 1 - INSERM
All About Hearing Loss
Types of Hearing Loss
Hearing losses may be located in the external, middle or inner ear or both. These different types
of hearing loss are described below.
Conductive Hearing Loss
If there is a problem in the external or middle ear, a conductive hearing loss exists. This means
sound is not being conducted properly to the inner ear.
Common causes of conductive hearing loss are wax (cerumen) in the external ear, fluid in the
middle ear, or a hole or tear (perforation) in the eardrum. Most types of conductive hearing loss
can be treated medically or surgically.
Below are pictures of a normal ear drum, middle ear with fluid, and an eardrum with a perforation.
Normal Eardrum
Middle Ear Fluid
Eardrum Perforation
Michael Hawke, M.D., Diseases of the Ear, published by Manticore Communications
Cross section of the middle ear showing
middle ear fluid
Sensorineural Hearing Loss
If a problem occurs in the inner ear, the hearing loss is sensorineural. Common causes of
sensorineural hearing loss in young children are certain pre-natal infections, lack of oxygen
during birth, or genetic factors. Sensorineural hearing loss usually cannot be cured medically or
surgically, but the use of hearing aids or other amplifying systems can help children hear and
develop speech and language.
Mixed Hearing Loss
Children with sensorineural hearing loss also can develop middle ear problems (such as fluid in
the middle ear) This can make the infant's hearing loss worse. When there is a combination of
two problems (sensorineural and conductive hearing loss), this is known as a mixed hearing loss.
All About Hearing Loss
What Is An Audiogram?
shaded region shows the level and
frequency of average speech
When your baby is a bit older, the pediatric audiologist will measure his or her
hearing and plot a graph called an audiogram. An audiogram is a graph used
to show the softest sounds that a person can hear at
different pitches.
The graph shows this range of sounds included in typical
speech. Different sounds in our language vary in their
pitch and loudness. For example, the "s" sound you use
in the word "cats" is high in pitch and fairly soft. In
contrast, the "o" sound in "bow" is low in pitch and fairly loud. The frequency
and loudness of individual speech sounds are also shown on the audiogram.
Hearing is tested using earphones or loudspeakers. These send sounds to the
ear canal and through the middle ear to reach the inner ear. This is known as
air conduction testing.
If air conduction testing shows a hearing loss, another device, a bone vibrator,
is placed behind the ear to send sounds directly to the inner ear. The sound
bypasses the ear canal and middle ear.
With conductive hearing loss, sounds can be heard at softer levels with the
bone vibrator than with the earphone. With sensorineural hearing loss, sounds
will be heard at similar levels through both devices.
Now, you can experience what hearing loss
sounds like in comparison to normal
hearing.
The audiogram to the right shows normal
hearing.
Click for an example of normal hearing
file type
This audiogram shows a mild highfrequency hearing loss. A child with this
degree of hearing loss will have trouble
hearing and understanding soft speech,
speech from a distance or speech in a
background of noise.
Click for an example of mild hearing loss
file type
The audiogram here shows a moderate
high-frequency hearing loss. A child with
this degree of hearing loss will have
difficulty hearing conversational speech
even at close distances.
Click for an example of moderate hearing
loss
file type
The audiogram here shows a severe
hearing loss. A child with this hearing loss
may only hear very loud speech or loud
environmental sounds.
Click for an example of severe hearing
loss
file type
All About Hearing Loss
Hearing Tests to Expect As Your Child Grows
As your child grows, a variety of hearing tests will be conducted by the Audiologist.
Birth to 6 Months of Age
Currently, a diagnostic auditory brainstem response (ABR) test is the only method
available for testing hearing in newborns and infants up to 6 months of age.
While this test is similar to the ABR screening that is often performed in newborn
nurseries, the diagnostic ABR gives more detailed information about the degree of
hearing loss across frequencies in both ears. This is also known as a frequencyspecific ABR.
Under two months of age, this test can be performed while a baby is sleeping
naturally. If a baby is older or very active, a liquid medicine may be used to help
your baby sleep.
For this test, small bandaid-type electrodes are placed behind each ear and on
your baby's head. Sounds are then presented to the ears using miniature
earphones. The electrodes pick up responses from the hearing nerve and are
displayed on a computer screen. This test usually lasts about 2 hours.
Infants and Toddlers (6 mos. - 24 mos.)
Children older than 6 months can be tested using a behavioral technique known as
Visual Reinforcement Audiometry (VRA). With this test, a sound is presented either
through miniature earphones or a loudspeaker.
The child is trained to turn to the sound by the use of an animated toy. By using
this technique, it is possible to obtain detailed information about the child's hearing
loss across frequencies in both ears. Test results are graphed on an audiogram.
Young Children and Preschoolers (24 months - 5 years)
Children in this age range are tested using Conditioned Play Audiometry (CPA).
This is a game-like activity where the child is asked to do a specific task, such as
dropping a block in a bucket, every time a sound is heard. Typically, sounds are
presented through miniature earphones and results are graphed on an audiogram.
As with VRA, it is possible to obtain detailed information about the child's hearing
loss across frequencies in both ears.
Other tests may be conducted in addition to the standard tests that are run at
specific ages.
Tympanometry
Tympanometry is used to determine if the baby's middle ear is functioning
normally. This test is important because fluid in the middle ear or other
abnormalities can affect hearing responses.
This test is performed by placing a small earphone in
the baby's ear canal and gently changing the air
pressure in the ear. This test is helpful in identifying
the presence of an ear infection and/or fluid in the
middle ear.
A normal tympanogram shows a
definite peak at normal
room pressure (0)
An ear with fluid will show a
flat tympanogram
Other patterns are found with various middle ear
problems, including eardrum perforations, eustachian
tube problems, etc. If the tympanogram shows a
tracing that is not normal, your baby may be referred
to his/her physician.
Tympanogram testing also may be used to evaluate if
pressure equalization (tympanostomy) tubes are
present and working correctly. Your child's physician
and audiologist use both the tympanogram and ear
examination results to see if the tube is open. The
picture to the right shows an ear drum with a
tympanostomy tube in place.
Tympanostomy Tube in Place
Diagnostic Otoacoustic Emissions (OAEs)
Diagnostic otoacoustic emissions generally are used in combination with ABR and
behavioral audiometric results. A miniature earphone is placed in the ear canal and
a series of tones are presented. The sensitive microphone measures an echo from
the inner ear. This information helps define your child's type of hearing loss.
Causes of Hearing Loss
Parents who have just received word that
their child has a hearing loss can display a wide range of reactions.
A common feeling that most parents experience is wondering what
caused their child's hearing loss.
This section will help parents begin to answer that question. We will
walk you through the process that medical professionals use to discover the cause of a
hearing loss and determine the appropriate treatment. The emphasis will be on some of
the more common causes of hearing loss. Trying to come up with an answer to the question of
what caused a hearing loss is somewhat like putting together a jigsaw puzzle. Unfortunately, we
do not always have all the pieces to that puzzle and there is not a final picture to guide us. Each
physical finding, medical test result, and piece of family medical history provides a piece of the
puzzle. Sometimes, one of those pieces can "fill in" a big enough section of the puzzle that the
medical professionals feel confident that they know the cause of the hearing loss. It is also
possible that after all the testing, after all the questioning, and after all the examinations, the
answer remains unclear. You may be told that the cause of the hearing loss is still unknown.
Causes of Hearing Loss
Non-Genetic Hearing Loss
In about 25% of cases of hearing loss there is a non-genetic cause that can be identified. Nongenetic hearing loss is most often caused by illness or trauma before birth or during the birth
process. Older infants and young children can also develop non-genetic hearing loss due to
illness or trauma.
Some viral infections are known to be associated with hearing loss. These infections carry the
highest risk of causing hearing loss if the mother has the illness during pregnancy or passes the
infection to her baby during the birth process. The primary infections are Toxoplasmosis (Catscratch disease), Syphilis, Rubella (German Measles), Cytomegalovirus (also known by the
initials CMV) and Herpes. The amount of hearing loss that can result varies widely and some
babies show no hearing loss at all, even if they have one of these infections. These infections can
affect other systems in the body as well and medical professionals will need extensive birth
history and test information to identify these infections as a cause for hearing loss.
Low birth weight has also been identified as a risk factor for hearing loss. Newborn specialists
identify 1500 grams (approx. 3.3 lbs.) as a cut-off point, with children weighing less than 1500
grams having an increased likelihood of hearing loss.
Hyperbilirubinemia (jaundice) that is severe enough to require a blood transfusion can also result
in hearing loss. This is related to the potential damage that high levels of bilirubin can cause to
the nerves of hearing.
Sometimes medications that are known to be ototoxic (damaging to hearing) are prescribed to
babies, usually to treat serious infections or birth complications. The most common otoxic
medications used at this time include a family of antibiotics called aminoglycosides with names
such as gentamycin, tobramycin, kanamycin. and streptomycin. Hearing loss resulting from the
use of these antibiotics may also have a genetic component. They present more of a risk to
hearing when they are used multiple times or in combination with other medications, such as
diuretics. Although cancer in infants and young children is rare, there are some chemotherapy
drugs that are used which are also ototoxic, especially when used to treat tumors that are in the
skull.
All babies are evaluated at birth on a 10-point scale, called an APGAR score, for A: Activity
(muscle tone); P: Pulse; G: Grimace (reflex irritability); A: Appearance (skin color); and R:
Respiration. Newborns are given APGAR scores at 1 minute and 5 minutes
after birth. The higher the score, the healthier the baby is. When babies
have scores of 0-4 at one minute or 0-6 at five minutes, their risk for having
hearing loss increases. Also, prolonged mechanical ventilation for a
duration of five days or longer due to persistent pulmonary hypertension
increases the risk for hearing loss. These conditions of breathing problems and other distress at
birth do not mean that a baby will always have a hearing loss, but do indicate the need to
monitor hearing closely.
One illness that carries a high risk of causing hearing loss and/or balance problems is bacterial or
viral meningitis. Because of improvements in immunizations, the cases of bacterial meningitis
have declined sharply in recent years, but immunizations are not available for the viral type of this
infection. Because meningitis is an infection of the lining of the brain and spinal cord, the sense
organs of hearing and balance are especially sensitive to this infection.
It is clear that non-genetic hearing loss can result from a wide variety of illnesses and problems at
birth. Medical professionals depend on a careful review of birth information to help them identify
non-genetic hearing loss.
Causes of Hearing Loss
How do genetic professionals view hearing loss?
Most genetic professionals working with hearing loss are in general agreement that the cause of
hearing loss in about one-quarter of cases is Unknown, one-quarter Non-genetic, and about
one-half Genetic. For the purposes of this section, we will only focus on the genetic causes.
Within the genetic half, about 70% of cases are generally thought to be recessive in nature, about
15% dominant and the remainder include all other inheritance types. The next section will explain
these genetic terms in more detail.
Genetic
50%
Non-genetic Unknown
25%
25%
Understanding genetics and inheritance
Many parents are unfamiliar with how hearing loss could be caused by genetic factors. As you
work through the process of identifying the cause of your child's hearing loss, it will be helpful to
have a basic understanding of genetics and the major categories of inheritance. If you are already
familiar with genetic concepts, this list briefly summarizes the important points of genetic
inheritance:
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Genes code for messages.
Genes are found on chromosomes.
Chromosomes come in pairs called homologs.
The messages on each of the chromosomes in a pair may be different; those differences
determine dominant or recessive expression of the gene message.
The major forms of inheritance are Dominant, Recessive and Sex-linked.
There are other types of inheritance.
Causes of Hearing Loss
Basic Genetics
What Are the Most Common Forms of Genetic Hearing Loss?
Of the 50% of the genetic forms of hearing loss, an estimated 70% are due to recessive causes,
about 15% have a dominant cause; and the remaining 15% include all the other forms of
inheritance.
GENETIC
RECESSIVE 70%
DOMINANT 15%
OTHER GENETIC 15%
NON-GENETIC AND
UNKNOWN
Genetic scientists subdivide genetic hearing loss into two general categories: "Non-Syndromic"
(meaning hearing loss and nothing else) and "Syndromic" (meaning hearing loss with other
clinical findings). By far, the more common is Non-syndromic hearing loss which includes 2/3 of
all genetic hearing losses.
SYNDROMIC
NONSYNDROMIC
RECESSIVE RECESSIVE
DOMINANT DOMINANT
OTHER
OTHER
GENETIC
GENETIC
NON-GENETIC AND
UNKNOWN
What is the Most Common form of genetic hearing loss?
One gene, known as Connexin 26 (abbreviated CX26), is estimated to be responsible for half of
all the recessive cases of hearing loss. There are over 400 known genetic causes involving
hearing loss. CX26 alone is responsible for about 1/3 of all the cases of genetic hearing loss!
SYNDROMIC
NONSYNDROMIC
CONNEXIN26
RECESSIVE
DOMINANT
OTHER
GENETIC
RECESSIVE
DOMINANT
OTHER
GENETIC
NON-GENETIC AND
UNKNOWN
What are the Next Most Common Forms of Genetic Hearing Loss?
Since CX26 accounts for about 1/3 of all cases of genetic hearing loss, that leaves about 1/3 of
all cases as non-syndromic (this includes all types of inheritance) with the remaining 1/3 as
syndromic. Among the remaining 1/3 of non-syndromic cases of genetic hearing loss, 13
dominant and 8 other recessive genes have been described.
What are the Common Dominant Syndromic Hearing Loss Types?
The following descriptions are only a brief review. Medical professionals can guide you for further
information. About 5% of all hearing loss is dominant syndromic in nature.
http://www.familyvillage.wisc.edu/index.htmlx
Waardenburg Syndrome - The hearing loss in Waardenburg Syndrome may be present
in one or both ears and is a sensorineural type of loss. The striking features of
Waardenburg syndrome may include: premature graying hair, white forelock, fused
eyebrows (synophrys), two different-colored eyes (heterochromia irides, usually bright
blue and brown), widely-spaced eyes (hypertelorism), high nasal bridge, under-developed
nose tip (hypoplastic alae nasia) and partial albinism.
http://www.boystownhospital.org/parents/info/genetics/waardenburg.asp
http://www.nidcd.nih.gov/health/pubs_hb/waard.htm
Branchio-Oto-Renal (BOR) Syndrome - The hearing loss in BOR Syndrome is conductive,
sensorineural or mixed. Cysts (or pits) can be found on the neck (branchial cleft) or in front of the
outer ear (prearicular). The outer ear (pinna) may be malformed and stapes fixation, inner ear
malformations and/or enlarged vestibular aqueducts may be present. A major medical concern
with BOR are the associated renal (kidney) problems, which could be life threatening.
http://www.boystownhospital.org/parents/info/genetics/bor.asp
Neurofibromatosis Type II (NFII) - The hearing loss in NFII is progressive sensorineural leading
to possible deafness. Café-au-lait (coffee with cream-colored) spots may appear on the skin, with
freckling and cataracts. Acoustic tumors may grow on the VIIth cranial nerve, causing hearing
loss. Tumors may also grow on other nerves. http://www.nfinc.org/ http://neurofibromatosis.org/
http://www.vh.org/Providers/TeachingFiles/RCW/080495/NeuroFibroHome.html
Stickler Syndrome - The hearing loss in Stickler Syndrome is usually conductive, although some
losses may be mixed or sensorineural. Progressive hearing loss has also been reported. There
are three syndrome types. All are related to altered expression of a collagen/connective tissue
gene. Associated features may include: cleft palate, downward-placed tongue (glossoptosis),
small jaw (micrognathia), under-developed midface, progressive severe near-sightedness
(myopia), cataracts, retinal detachment/degeneration, bone/joint disorders, early adult-onset
arthritis, and middle ear bone (ossicular) malformations. http://www.sticklers.org/sip/
Treacher-Collins Syndrome - The hearing loss in Treacher-Collins is conductive. Striking facial
features include cleft palate, down-slanting eye-slit openings (palpebral fissures), unusual pupil
openings (coloboma), under-developed cheek bones (malar hypoplasia), absent/malformed outer
ears, absent (atresia) or narrow (stenosis) ear canals, skin tags in front of the ear (prearicular),
teeth alignment problems (malocclusion) and possible balance (vestibular) problems.
http://www.treachercollinsfnd.org/
What are the Common Recessive Syndromic Hearing Loss Types?
Recessive Syndromic hearing loss accounts for about 20% of all types of genetic hearing loss.
Usher Syndrome - There are three (3) types of Usher syndrome with different types of hearing
loss. Type I has congenital, profound, sensorineural hearing loss. Type II has a downwardsloping, sensorineural hearing loss. Type III has a progressive sensorineural hearing loss. All
types have balance (vestibular) problems and progressive vision loss due to retinal degeneration
(retinitis pigmentosa). http://www.nidcd.nih.gov/health/pubs_hb/usher.htm
Alport Syndrome - Hearing loss in Alport syndrome may be sensorineural, conductive or mixed
and may be progressive. Alport syndrome may also be X-linked (linked to sex-chromosome
inheritance). Other features include kidney problems (nephritis), near-sightedness (myopia) or
cataracts, and palate abnormalities. http://www.cc.utah.edu/~cla6202/ASHP.htm
Jervell and Lange-Nielson Syndrome - The hearing loss in JL-N
syndrome is sensorineural. The other major finding in JL-N is an abnormal
heart rhythm (long Q-T), which could lead to fainting spells and possible
sudden death. These might be mistaken for seizures. These abnormal
heart rhythms are successfully treated with medication (beta blockers).
Pendred Syndrome - The hearing loss in Pendred syndrome may be mixed or sensorineural
and may be progressive. Pendred Syndrome may have an associated goiter,and variable inner
ear malformations (Mondini malformation with or without enlarged vestibular aqueduct).
http://www.medicinenet.com/Script/Main/Art.asp?li=MNI&ArticleKey=9460
What are Some Less-Common Syndromic Hearing Loss Types?
CHARGE Syndrome - The letters in CHARGE stand for Coloboma, Heart, Atresia of the
choanae, Retardation of growth and development, Genital and urinary abnormalities, and Ear
abnormalities. CHARGE is thought to be multifactorial. The hearing loss may be conductive,
sensorineural or mixed and range from mild to profound. In addition to the features in the name,
there may be partial facial paralysis, cleft palate, cleft lip, kidney problems, and feeding problems
due to an opening between the windpipe and the feeding tube. http://www.chargesyndrome.org/
X-Linked Congenital Stapes Fixation with Perilymph Gusher - For boys with this syndrome,
the hearing loss is mixed and may be progressive. Females who carry this gene may have mild,
mixed or sensorineural hearing loss. Boys with this gene have a further risk of increased hearing
loss if middle ear surgery is performed to correct the stapes fixation because the surgery may
result in massive and sudden loss of inner ear fluid (perilymph).
Mitochondrial Conditions
Mitochondria are structures in the cell that produce the energy that cells need to survive. Neither
the mitochondria nor the cell can exist without the other. Interestingly, mitochondria have a
separate set of genes that are not part of the cell's genes. This is because mitochondria originally
came from energy-producing bacteria that merged with the cell. Anything that affects bacteria
could also affect the function of the cell's mitochondria, which might eventually affect the cell's
energy source. Changes in the mitochondrial genes can also result in syndromes involving
hearing loss.
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Mitochondrial Encephalopathy, Lactic Acidosis and Stroke-like Episodes
(MELAS) - About 30% have sensorineural hearing loss. The findings are highly
variable and may include: intermittent vomiting, limb weakness, stroke-like
episodes, partial paralysis, partial blindness, seizures, migraine-like headaches,
diabetes, short stature, heart problems and kidney problems.
Maternally Inherited Diabetes and Deafness (MIDD) - The hearing loss is
sensorineural. The only other finding is diabetes.
Kearns-Sayre Syndrome (KSS) - The hearing loss is sensorineural. Other
findings include: unsteady gait (ataxia), short stature, delayed puberty,
progressive paralysis of the eye muscles (ophthalmoplegia) and progressive
blindness (retinopathy).
Myoclonic Epilepsy and Ragged Red Fibers (MERRF) - The hearing loss is
sensorineural. Other findings include unsteady gait (ataxia), epilepsy, and
possible blindness (optic atrophy).
1555DELG - The hearing loss is sensorineural and may be progressive. Those
who have this condition may have sudden hearing loss when exposed to
aminoglycoside antibiotics (e.g., neomycin, gentamycin, streptomycin,
kanamycin, tobramycin, or amikacin).
Causes of Hearing
Loss
asked
Answers to some frequently
questions
Why did this happen to my child?
Hearing science professionals estimate that 1 in 300 babies are born with some degree of
hearing loss. Human genetic professionals estimate that half of those cases of hearing loss are
due to the genes that the baby inherited. About 12 babies per 10,000 have a recessive cause of
their hearing loss. Congenital hearing loss (hearing loss present at birth) that is due to one of the
many recessive genes is about twice as common as Cystic Fibrosis, another recessive genetic
condition.
To answer the question, "Why did this happen to my child?" there could be at least one of three
answers.
1. Unknown (the cause of the hearing loss cannot be discovered)
2. Non-genetic (illness or trauma before, during or after birth)
3. Genetic (the hearing loss will depend on the type of inheritance present)
In 70% of cases of genetic hearing loss, the cause is autosomal recessive; therefore,



Both parents are "carriers" of a gene that causes recessive hearing loss.
There are many different genes in many different locations that may cause genetic
hearing loss. At one of these locations, a parent my carry one of the recessive genes that
can cause deafness and one of the dominant genes that is responsible for normal
hearing. Because each parent has only one recessive gene that can cause hearing loss,
both parents can hear.
If each parent passed on one recessive gene, then the child would receive two recessive
genes (one from each parent) and that is the cause of the recessive hearing loss.
In 15% of cases of genetic hearing loss the cause is autosomal dominant.


In this case only one parent may have the dominant gene for hearing loss. That parent
will have some degree of hearing loss. If the autosomal dominant gene also has other
physical findings (i.e., it is syndromic), the parent who has the dominant gene also may
have some of these other physical findings.
The parent with the dominant gene may pass that gene for hearing loss on to the child.
For the final and remaining 15% of genetic hearing loss cases, the answer to the question, "Why
did this happen to my child?" is specific to the particular type of genetic inheritance.
Why is my child being referred for Genetic Testing?
Genetic testing may determine whether your child's hearing loss is due to non-genetic causes or
to a gene that causes hearing loss. From this information, professionals can calculate the
likelihood that other children in your family may also have a hearing loss due to the same cause.
A full genetic evaluation will also determine if there are other health conditions that also need to
be addressed.
What does this mean for my child?
In general, why your child has a hearing loss does not affect how your child will be educated.
Management of your child's hearing loss will be based upon the specific characteristics of your
child and his or her communication needs. The findings from
a genetic evaluation may be relevant for your child's medical
care
What is the likelihood that this will happen again with any other children in my family?
If the cause of your child's hearing loss is an autosomal recessive gene, then the likelihood that
this will happen in another child (assuming the same partner) is 1 in 4 (25%).
If the cause of your child's hearing loss is an autosomal dominant gene, then the likelihood that
this will happen in another child (assuming the same partner) is 1 in 2 (50%).
Should I have my other children tested?
If it is determined that you and your partner carry the silent (recessive) gene which causes a
hearing loss, then each of the children resulting with that partner have a 2 in 3 (66%) chance of
also carrying that same gene.
Whether or not your hearing children should be tested to determine if they also carry the
deafness gene is a matter of choice. Your hearing children may want to know their own gene
carrier status so they would know whether to have their partners tested to determine if their
children (your grandchildren) have a chance of having hearing loss due to this gene.
There is a 2 in 3 chance that hearing siblings (brothers and sisters) of a child with recessive
hearing loss carry the hearing loss gene (like you and your partner). If this is the case, then their
life partner could be tested to determine if they are also a carrier. If that partner is also a carrier of
the same gene, then each of their children would have a 1 in 4 (25%) chance of having the same
genetic hearing loss. If that partner does not carry the same gene, then all of their children would
be hearing, although each child would have a 50% chance of carrying the hearing loss gene.
There is a 1 in 3 chance that hearing siblings do not carry the recessive hearing loss gene. If this
is the case, there is virtually no chance of having a child with a hearing loss due to this gene, as
the gene is not passed on.
Is this something that I need to be concerned about in my other relatives?
If you and your partner carry a recessive gene, then at least one of your parents and one of your
partner's parents also carry the gene. This means that each of your brothers and sisters has a 1
in 2 (50%) chance of carrying the same gene.
What will all this cost?
The monetary costs of a genetic evaluation and medical tests are generally covered by your
health insurance. Families should always check with their health insurance carrier to determine if
genetic and medical tests are covered under their particular plan.
Some people experience the psychological cost of guilt that they were responsible for this
condition in their child. Be assured that everyone carries some recessive genes that, if present in
a double dose, would cause some sort of genetic condition. Guilt feelings are natural during the
stages of grieving and acceptance of your child's hearing loss. However, if those feelings persist
or if they affect your ability to function day-to-day, please seek out someone who can help.
Causes of Hearing Loss
Glossary
Autosomes - The 22 pairs of
chromosomes that contain
genes that do not determine your sex. These are numbered
from the largest (#1) to the smallest (#22) pairs.
Chromosome - A collection of many hundreds or thousands of genes strung together like beads
on a string. There is no rhyme or reason for the order of the genes on a chromosome. Humans
usually have 46 chromosomes (23 pairs) and they are found in the nucleus of each cell in your
body (with the exception of the cells responsible for reproduction). One pair of chromosomes
determines your sex (Sex Chromosomes); all the other chromosomes are called Autosomes.
Think of a chromosome as one of a volume of books, each containing many sentences (genes).
Since chromosomes come in pairs, then genes also come in pairs. This is the basis for the
different types of inheritance: Dominant and Recessive.
Dominant gene (inheritance) - Since genes come in pairs, a dominant gene is always
expressed (message is read) regardless of the message on the other gene.
Gene - A coded message that tells the body how to make a chemical substance that the body
needs. For example, the gene that codes for the molecule hemoglobin, which carries oxygen in
the red blood cells, is found in humans on chromosome #9. Think of a gene as a sentence in a
book.
Hearing Loss - The condition of less than full hearing capacity. The degree of hearing loss can
have different terms; hard of hearing, hearing impaired and deaf are three of the more common
terms. Unless otherwise specified, hearing loss includes all of these sub-classifications.
Recessive gene (inheritance) - If paired with a Dominant gene, the message of the recessive
gene will not be expressed. However, if paired with another recessive gene, then the message
will be expressed.
Sex Chromosomes - The one pair of chromosomes that determine your sex. In humans,
females have two "X" chromosomes, while males have one "X" and one "Y" chromosome.
Therefore, human males determine the sex of the children (whether the sperm contains the "X" or
"Y" chromosome).
Cochlear Implants
Cochlear implants are devices that can provide sound for people who receive little or no benefit
from hearing aids. Hearing aids make sounds louder. However, for children and adults who have
severe to profound hearing loss, making sounds louder may not be enough to allow the ear to
process sound. A cochlear implant may be more successful than hearing aids in some cases,
because it bypasses the damaged sense organ of hearing (cochlea) and directly stimulates the
hearing (auditory) nerve. Part of the cochlear implant includes tiny electrodes that are surgically
inserted into the cochlea. The cochlear implant converts sound into electrical signals that go to
the auditory nerve. This section includes information on how the cochlear implant works, who is a
candidate, and how to help children learn to listen with this device.
Cochlear Implants
What Is a Cochlear Implant and How Does it Work?
Cochlear implants are implantible devices designed with the goal of providing sound detection
and speech recognition for people who receive little or no benefit from hearing aids. There are
several manufacturers of cochlear implants such as Advanced Bionics Corporation, Cochlear
Americas, and Med-El. The cochlear implant-regardless of the manufacturer-is comprised of both
internal and external components.
The internal portion, which is implanted surgically, has a receiver and tiny electrodes. The
receiver is imbedded under the skin behind the ear and the electrodes are surgically inserted into
the cochlea.
The external portion, shown in the picture below includes a speech processor that is connected to
a headpiece by a cord. The headpiece has a transmitting coil that sends the signal from the
speech processor to the internal part of the device. It magnetically attaches to the surface of the
head behind the ear at the spot where the internal portion of the implant is located.
Platinum Series
Auria Processor
Sprint Processor
Esprit Processor
There are additional speech processors and configuration options
available other than those shown above
The internal and external portions work together to change sound into electrical signals that are
sent to the hearing nerve. First, the microphone picks up the sound energy, and transmits the
signal through the cord to the speech processor. The speech processor filters, analyzes, and
converts the sound energy into a digital code that is then sent back through the cord to the
headpiece where it is transmitted across the skin, via radio frequencies, to the internal receiver.
Then, the internal receiver delivers the signal to the electrodes that have been placed inside the
cochlea. The electrodes bypass the damaged parts of the cochlea and send a tiny electrical
charge directly to the auditory nerve. Finally, the auditory nerve carries these electrical signals to
the brain where they are interpreted as sound. This process occurs so rapidly that the listener will
hear speech and other sounds without any noticeable delay.
Cochlear Implants
Is My Baby a Candidate for a Cochlear Implant?
The criteria for determining who can benefit from cochlear implants
have changed a great deal since the devices were first introduced.
Currently, cochlear implants are approved by the Food and Drug
Administration (FDA) for children 12 months of age and older.
Criteria for Cochlear Implantation in Children:

In general, it is recommended that a child be appropriately fit
with hearing aids and use them for 3-6 months before
determining implant candidacy.
In cases of meningitis, a shorter hearing aid trial may be
recommended or the trial may be waived as bony growth in
the cochlea following meningitis may create problems for implantation. In a few cases of
meningitis, the physician may proceed with implantation prior to the child reaching 12
months of age. This is to insure adequate insertion of the electrodes into the cochlea,
before the bony growth fills the cochlea.

Degree of hearing loss
Children between 12 months and 18 months of age: Profound, sensorineural hearing loss
of 90
decibels
or greater
in both ears
Children 18 months of age and older:Severe-to-profound sensorineural hearing loss of 70
decibels or greater in both ears
To learn more: What is an Audiogram?

Lack of benefit from appropriately set hearing aids
Examples of this would include:
—Inconsistent response to his/her name in quiet
—Failure to alert to environmental sounds while wearing amplification

No medical contraindications
Included in the list of contraindications are things such as an absence of the auditory
nerve; medical conditions or developmental delays that would severely limit participation
in aural habilitation; and active middle ear infections.

Children should be in a rehabilitative or educational setting where the development of
auditory (listening and speaking) skills is emphasized. Rehabilitative or educational
environments that encourage auditory skill development are likely to have a positive
effect on the speech and language progress in children.

High motivation, positive family environment, and realistic expectations are all important
factors in a child's performance with the cochlear implant.
Cochlear Implants
Follow-up and Rehabilitation
Cochlear implant surgery requires general anesthesia and lasts about 2 to 3 hours. Surgery is
usually completed as an outpatient procedure, and may include a one-night stay in the hospital. It
generally takes 3 to 5 weeks for the surgical incision to heal, but most children resume normal
activities within days after the surgery.
Between 4 to 6 weeks after surgery, the child will return to the clinic to have the device activated
for the first time. During the time between surgery and implant activation, the child will not be able
to wear a hearing aid in the implanted ear and so will not be able to hear in that ear. If a hearing
aid is worn in the non-implanted ear, the child should continue to wear this aid during the time
between surgery and activation. Some children will continue to wear a hearing aid in their nonimplanted ear to improve localization and listening in noise.
Device activation may be either a one or two-day process. Up to 20 return visits may be needed
within the first year for both fine-tuning of the speech processor and auditory training or aural
rehabilitation.
Cochlear Implants
Expectations
What exactly is meant by "benefit" or "success" with a cochlear implant? It is important to keep
several important facts in mind:

The benefit from cochlear implants is not often
immediate.
 Improvements occur over a period of months or
even years.
 The amount of benefit seen is linked to the age of
a child at the time of implantation, the cause of the hearing loss, and family
support and involvement.
Reasonable expectations may include improved detection of environmental sounds and speech,
improved speechreading ability, and improved clarity of the child's speech. How much speech
understanding a child with a cochlear implant will obtain and how clear his or her speech will be is
difficult to predict.
Cochlear implant surgery should be viewed as the first step in a long process. Parents should
understand that their participation is crucial in their child's educational process so that the most
benefit can be achieved.
Children with cochlear implants need support services from a number of professionals for
educational and speech language development. The amount of support needed is variable from
one child to the next. A child's performance with a cochlear implant cannot be predicted. Each
child will have varied performance with the cochlear implant. Each child will have varied
performance with the cochlear implant. However, providing the right support services and
environment can optimize learning and development. It is important to remember that it can take
up to one year after the implant is activated for distinct changes to show in a child's ability to
communicate.
In a small number of cases, a child may show only limited benefit from the cochlear implant or
seemingly no benefit at all. This can generally be linked to a significant malformation of the
cochlea or to a hearing nerve that has a very limited number of nerve fibers. In other words, the
cochlear implant is sending a signal, but the structures needed to pass the signal on to the brain
are not there.
A variety of school placements are possible for children with cochlear implants.. To make the
most of a cochlear implant, a child needs be in a program that clearly states and supports
listening and speaking goals. Children in auditory oral, simultaneous communication, or manual
communication programs can all benefit from listening therapy or auditory training. All programs
regardless of communication modality can emphasize listening and speaking goals. The types of
communication modalities most commonly used are described on the Getting Started page. It is
important to keep in mind that a child's individual communication goals, strengths, and abilities
should be used to determine the educational setting. Placement should not be based solely on
the fact that a cochlear implant is in use, and educational and support service needs must be
assessed for each child.
Hearing Aid Choices
Fitting appropriate hearing aids or other sensory devices is one of the first steps in helping an
infant with hearing loss. Today's advanced technology allows for the successful fitting of hearing
aids on very young babies.
Because language skills begin to develop within the first few months of life, it is important to have
your baby fitted with hearing aids as soon as possible. However, hearing aids are complex. There
is much to learn about these devices and there are many decisions to make.
The next section answers questions about the many different types of hearing aids and how they
work. You will also find practical ideas for hearing aid use.
Hearing Aid Choices
What are the different styles of hearing aids?
There are two basic kinds of hearing aids typically recommended for children:
Behind-the-ear (BTE)
hearing aids
In-the-ear (ITE) or in-the-canal
(ITC) hearing aids
The most commonly used and most appropriate style for infants and young
children is the behind-the-ear (BTE) hearing aid.
Although there are many different types of in-the-ear (ITE) hearing aids, these
devices are best suited for adults. Generally, they are not appropriate for children
under 6-7 years of age. Why? Because young children's ear canals are small and
they grow rapidly during the first few years of life. This means that they would
quickly outgrow their hearing aid cases. Also, ITE hearing aids are made from a
hard plastic that can cause severe injury to a child's ear canal if the hearing aid
becomes damaged.
Many years ago, children used body hearing aids. Because these aids are heavy,
cumbersome, and the cord can pose a strangulation risk, body aids are rarely used
today and only under special circumstances.
Hearing Aid Choices
How does a hearing aid work?
All hearing aids, regardless of style, are made with the same basic parts. In the
behind-the-ear (BTE) hearing aid, shown below, you can see the microphone,
tone hook, volume control, on/off switch, and battery compartment.
The microphone picks up sounds from the environment and sends them to a
processor that amplifies the signal (makes it louder). The hearing aid will
amplify some pitches of the incoming sound more than others depending upon
your child's hearing loss. Your audiologist uses the hearing aid's tone controls
(located on the reverse side of the instrument) to make the amplified sound
appropriate for your child's hearing loss.
After the sound is amplified, it is routed through the hearing aid tone hook to
an earmold which is custom made for each child. The tone hook is a small
plastic piece that hooks over and behind the child's outer ear (pinna). The
earmold holds the hearing aid in the child's ear and directs sound from the
hearing aid into the ear canal. Earmolds are made from soft materials after an
impression is taken of your child's ear. They are made individually for each
child and fit snuggly in the ear canal. As a baby grows, earmolds need to be
replaced on a regular basis.
Hearing Aid Gain
The graph below shows how much the hearing aid increases the level of
sound at different pitches (frequencies). This is known as hearing aid gain. For
mild hearing losses, small amounts of gain are needed. A severe hearing loss
requires more gain. When a hearing loss is different at each frequency, the
audiologist also has to adjust the gain of the hearing aid appropriately.
Hearing Aid Choices
How is a hearing aid fitted and evaluated on an infant or young child?
The process of fitting hearing aids to children is very different than it is for adults. Adults can tell
their audiologist how well a hearing aid seems to work, if certain sounds are too loud, or if speech
sounds garbled or unclear. Young children cannot do this. For this reason, it is important to find a
pediatric audiologist with extensive experience in fitting hearing aids to children. Because a
child's early years are particularly important for speech and language development, finding the
best hearing aids for each child is very important.
Hearing aids must be fit individually for each child. No one hearing aid is appropriate for
everyone. Some important factors that a pediatric audiologist will consider when selecting hearing
aids are:



Degree and shape of the hearing loss
Durability and service of hearing aid models
Compatibility with special amplification systems used in schools
Adult hearing aid users may sometimes choose to wear only one hearing aid. When fitting
hearing aids on infants and children, pediatric audiologists will almost always recommend hearing
aids for both ears. Two hearing aids are needed to support the child's learning of language and
speech. Even if a child has different degrees of hearing loss in each ear, hearing aids for both
ears usually will be recommended.
The best method of testing hearing aid benefit for young children is called probe microphone
testing. During this test, a small, soft microphone is placed in the child's ear next to the earmold.
This approach allows the audiologist to determine how much sound is being delivered to the
child's ear. Because infants and young children have much smaller ear canals than adults, it is
important to make these measures to avoid loudness discomfort and/or further damage to the
child's hearing.
For very young children, a special probe microphone technique
called Real-Ear-to-Coupler-Difference (RECD) measurement can
be used. The audiologist combines this information with the
response of the hearing aid measured in a test box to find the best
hearing aid and hearing aid settings without having to do repeated
hearing aid testing on the child. If an audiologist uses RECD
measures before fitting the hearing aid directly on the child, she/he
can avoid the problem of too much sound from the hearing aid or
inaccurate volume settings.
RECD testing is one of the most recent developments in hearing aid evaluation for infants and
young children. It is considered state-of-the-art for pediatric audiologists. Research studies have
shown that this type of testing is safe even with babies younger than 6 months.
The most important goal for infants and young children who wear hearing aids is making speech
loud enough for the child to hear. Probe microphone measures enable the audiologist to
determine how much of speech will be heard with different types of hearing aids. Audibility of
speech can be used to compare aided and unaided hearing, different hearing aid settings, and
different listening conditions.
The graphs above show how audible speech is for a child with a mild to severe sloping hearing
loss without a hearing aid (top panel) and with a hearing aid (bottom panel). The circles show the
child's hearing levels. The crosshatched areas show how much of speech is loud enough to hear
at a distance of 1 meter. The asterisks (*) on the lower panel show the loudest level that this
hearing aid can produce. Click on the loudspeakers to hear how speech would sound to this child
under these two conditions