Q: About how many deaf people
currently live in the United States and where can I find information about
the statistics in my area?
According to the National Center for Health
Statistics (2006), 37 million adults in the United States had trouble
hearing. The
following links provide more information about the number of persons with
hearing loss.
[Return to FAQs]
Q: What is the prevalence
(commonness) of hearing loss in children?
Hearing loss occurs in approximately 12,000 children
each year (up to 3 of every 1,000 births). According to the National
Institute on Deafness and Other Communication Disorders (NIDCD), about
28 million people in the U.S. have some degree of reduced hearing
sensitivity.
[Return to FAQs]
Q: What is degree of
hearing loss?
The degree of hearing loss refers to the severity of
the loss. There are several categories that are typically used. Different
groups and organizations define the levels of hearing loss differently.
For instance, the organization American
Speech-Language-Hearing Association (ASHA) measures hearing loss by using
the following categories:
Average Hearing Level (in decibels, dB)
A person with a hearing loss might be able to hear
some sounds or might hear nothing at all. Hearing loss can affect one ear
(unilateral) or both ears (bilateral), and can range greatly from person
to person. Below is just one way to measure hearing loss levels and what
can be heard without hearing aids or other devices to increase the sound.
Sound is measured in decibels. The numbers in parenthesis mark the range
of hearing loss in decibels.
Normal Range (-10–15 dB): A child will hear all
speech sounds.
Slight Hearing Loss (16-25 dB): A child will hear
vowel sounds clearly, but might miss some consonants sounds.
Mild Hearing Loss (26–40 dB): A child will hear only
some of the speech sounds.
Moderate Hearing Loss (41–55 dB): A child will hear
almost no speech sounds at a normal speaking level.
Moderate/Severe Hearing Loss (56–70 dB): A child will
hear no speech sounds at a normal speaking level.
Severe Hearing Loss (70–90 dB): A child will hear no
speech and almost no other sound.
Profound Hearing Loss (91+ dB): A child will hear no
speech and no other sound.
Source: American Speech-Language-Hearing Association,
(http://www.asha.org/public/hearing/disorders/types.htm)
While the American Academy of Otolaryngology uses the
following:
Mild = 15-40 dB
Moderate = 40-60 dB
Severe = 60-90 dB
Profound = over 90 dB
(Source:
AAO)
As the two examples above show some groups may use
slightly smaller or slightly larger numbers for each of the categories,
therefore each defines the levels of hearing loss differently. Because
the degrees of hearing loss have not been defined universally, it is
difficult to compare studies that give statistics. CDC is working to
obtain better estimates of the prevalence of hearing loss through
on-going research activities. Please check the CDC-EHDI website again, as
we will provide more statistics as they become available.
The following websites may also be useful. Please
note: not all of the information is complete and some of it focuses on
more than young children.
[Return to FAQs]
Q: What is the type
and severity of hearing loss in infants throughout the United States?
Please note that some of this information is estimated and
may not be exact. Not all states and territories were able to report this type
of data. For additional state and territorial data by year please
click here.
2006 Type and Severity Data
2005 Type and Severity Data
Summary of 2005 Type and Severity Data (by ear)
-
The 2005 type and severity data is by ear
instead of by child.
-
Please note that the 2005 data about type
and severity of hearing loss was collected using a different
survey than was used to collect the 2004 data.
2004 Type and Severity Data
Type and Severity for
Cases of Unilateral Hearing Loss (2004)
Type and Severity for
Cases of Bilateral Hearing Loss (2004)
2003 Summary
A
total of 44 states and territories reported that 2,899 infants born in
year 2003 were identified with a Permanent Childhood Hearing Loss (PCHL).
- The prevalence of PCHL among these states in
2003 = 1.09 per 1,000 infants screened
Type and Severity of PCHL
A total of 33 of these 44 states and territories reported
some data about the type and severity of identified PCHLs.
-
2,003
children were identified with a hearing loss within these 33 states and
territories.
-
The
prevalence of PCHL in these states = 1.16 per 1,000 infants screened.
|
Severity of PCHL |
Unilateral |
Bilateral |
|
|
|
|
|
Mild
|
31.1% |
26.1% |
|
Moderate |
31.8% |
28.3% |
|
Severe |
15.3% |
16.0% |
|
Profound |
12.0% |
18.0% |
|
|
|
|
|
Unknown |
9.8% |
11.6% |
Prevalence of Unilateral and Bilateral PCHL
A total of 516 cases of unilateral hearing loss were
identified in these 33 states and territories.
-
516/1,733,762* x 1,000 = 0.30 per 1,000
A total of 1,043 cases of bilateral hearing loss were
identified in these 33 states and territories
-
1,043/1,733,762* x 1,000 =
0.60 per 1,000
1,733,762*: Number screened for hearing loss within these
33 states and territories in year 2003.
[Return
to FAQs]
Q: What are common
symptoms of deaf or hard of hearing children?
-
Your child is inconsistently responding to sound
-
Language and speech development is delayed
-
Speech is unclear
-
Sound is turned up on electronic equipment (radio,
TV, cd player, etc.)
-
Your child does not follow directions
-
Your child often says "Huh?"
-
Your child does not respond when called.
If you have concerns, seek the services of an
audiologist certified by the American Speech-Language-Hearing
Association. Children's hearing can be tested as soon as they are born.
For further information, see the following sites:
http://www.ahaanet.com/signs_of_child_hearing_loss.asp
http://www.babyhearing.org
http://www.boystownhospital.org/Hearing/index.asp
[Return to FAQs]
Q: What are some medical
conditions that are linked to the chance of hearing loss in infants and
young children?
About 3 in 1,000 babies are born with some
degree of hearing loss. Children can also develop hearing loss after
birth.
Approximately 50% of hearing loss in children
has a genetic cause. Genetic causes have to do with the baby’s
genes. Genes are in the cells of a person’s body and contain
instructions that tell the cells of the person’s body how to grow
and work. For example, the instructions in genes control hair and
eye color.
-
About 30% of children with genetic
hearing loss have a “syndrome.” This means they have other
conditions linked with the hearing loss. Examples are Down
Syndrome and Usher Syndrome.
-
The other 70% of children with genetic
hearing loss have hearing loss that is “non-syndromic.” This
means there are no other conditions linked with the hearing
loss.
The following websites might also be useful.
Please note: Some of the information focuses adults and young
children.
Información en Español
DISCLAIMER:
Links to organizations outside of CDC are included for information
only. CDC has no control over the information at these sites. Views
and opinions of these organizations are not necessarily those of
CDC, the Department of Health and Human Services (HHS), or the U.S.
Public Health Service (PHS).
[Return to FAQs]
Q: Can an infant have both
syndromic and non-syndromic hearing loss?
No, infants with hearing loss have either a non-syndromic
form or a syndromic form.
Genetic causes of hearing loss can be “syndromic” or
“nonsyndromic”. Syndromic means that a person has other related symptoms
besides hearing loss. For example, some people with hearing loss are also
blind. Usher’s Syndrome is one example. There are many different
syndromes that have hearing loss as one of the symptoms. “Nonsyndromic”
means that the person does not have any other symptoms related to the
hearing loss. Whatever caused the hearing loss does not cause any other
symptoms. The more common type of genetic hearing loss is “nonsyndromic”
which includes 2/3 of all genetic hearing losses. A very common
“nonsyndromic” hearing loss is caused by one gene known as Connexin 26
(abbreviated CX26). CX26 alone is the cause in about 1/3 of all children
with a non-syndromic genetic hearing loss.
Non-genetic 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 a chance of causing infant hearing
loss if the mother has the illness during pregnancy or passes the
infection to her baby during the birth process. Cytomegalovirus (CMV) is
the most common of these viral infections.
Low birth weight (less than 1500 grams or
approximately 3.3 lbs) is also associated with hearing loss. Babies with
low birth weight are often born prematurely. Prolonged mechanical
ventilation (breathing with the help of a machine and breathing tube for
long periods of time) increases the chance of hearing loss in infants.
Jaundice at birth, severe enough to require a blood
transfusion, is also associated with hearing loss. High levels of
bilirubin, a chemical in the body that causes jaundice, can damage the
nerves that control hearing. Severe distress at birth also increases the
chance for hearing loss.
One illness that carries a high chance of causing
hearing loss is meningitis. Because meningitis is an infection of the
lining of the brain and spinal cord, the sense organs of hearing are
especially sensitive to this infection and can be damaged. Also,
medications that can be damaging to hearing are sometimes given to
infants or children to treat very serious infections. These medications
are usually not given for minor illnesses such as ear infections or even
pneumonia.
Unknown causes may be genetic or non-genetic. Because
of technology and medical breakthroughs, this category will probably get
smaller and smaller as more causes of hearing loss are understood.
For more information on medical causes of hearing
loss, please see
http://babyhearing.org/HearingAmplification/Causes/index.asp
http://www.boystownhospital.org/parents/info/genetics/ten.asp
[Return to FAQs]
Sorry, we can't give you medical advice. Please talk
with your doctor for questions about yourself or your family. For other
information, please contact ehdi@cdc.gov
[Return
to Top]
Date: September 1, 2006
Content source: National Center on Birth Defects and Developmental
Disabilities
