- What is a hearing aid?
- How can hearing aids help?
- How can I find out if I need a hearing aid?
- Are there different styles of hearing aids?
- Do all hearing aids work the same way?
- Which hearing aid will work best for me?
- What questions should I ask before buying a hearing aid?
- How can I adjust to my hearing aid?
- How can I care for my hearing aid?
- Are new types of aids available?
- Can I obtain financial assistance for a hearing aid?
- What research is being done on hearing aids?
- Where can I find more information?
What is a hearing aid?
A hearing aid is a small electronic device that you wear
in or behind your ear. It makes some sounds louder so that a person with
hearing loss can listen, communicate, and participate more fully in daily
activities. A hearing aid can help people hear more in both quiet and
noisy situations. However, only about one out of five people who would
benefit from a hearing aid actually uses one.
A hearing aid has three basic parts: a microphone,
amplifier, and speaker. The hearing aid receives sound through a
microphone, which converts the sound waves to electrical signals and sends
them to an amplifier. The amplifier increases the power of the signals and
then sends them to the ear through a speaker.
Top
How can hearing aids help?
Hearing aids are primarily useful in improving the hearing
and speech comprehension of people who have hearing loss that results from
damage to the small sensory cells in the inner ear, called hair cells.
This type of hearing loss is called sensorineural hearing loss. The damage
can occur as a result of disease, aging, or injury from noise or certain
medicines.
A hearing aid magnifies sound vibrations entering the ear.
Surviving hair cells detect the larger vibrations and convert them into
neural signals that are passed along to the brain. The greater the damage
to a person’s hair cells, the more severe the hearing loss, and the
greater the hearing aid amplification needed to make up the difference.
However, there are practical limits to the amount of amplification a
hearing aid can provide. In addition, if the inner ear is too damaged,
even large vibrations will not be converted into neural signals. In this
situation, a hearing aid would be ineffective.
How can I find out if I need a hearing aid?
If you think you might have hearing loss and could benefit
from a hearing aid, visit your physician, who may refer you to an
otolaryngologist or audiologist. An otolaryngologist is a physician who
specializes in ear, nose, and throat disorders and will investigate the
cause of the hearing loss. An audiologist is a hearing health professional
who identifies and measures hearing loss and will perform a hearing test
to assess the type and degree of loss.
Top
Are there different styles of hearing aids?
There are three basic styles of hearing aids. The styles
differ by size, their placement on or inside the ear, and the degree to
which they amplify sound (see figure on page 1).
-
Behind-the-ear (BTE) hearing aids
consist of a hard plastic case worn behind the ear and connected to a
plastic earmold that fits inside the outer ear. The electronic parts are
held in the case behind the ear. Sound travels from the hearing aid
through the earmold and into the ear. BTE aids are used by people of all
ages for mild to profound hearing loss.
A new kind of BTE aid is an open-fit hearing aid. Small, open-fit aids
fit behind the ear completely, with only a narrow tube inserted into the
ear canal, enabling the canal to remain open. For this reason, open-fit
hearing aids may be a good choice for people who experience a buildup of
earwax, since this type of aid is less likely to be damaged by such
substances. In addition, some people may prefer the open-fit hearing aid
because their perception of their voice does not sound “plugged up.”
-
In-the-ear (ITE) hearing aids fit
completely inside the outer ear and are used for mild to severe hearing
loss. The case holding the electronic components is made of hard
plastic. Some ITE aids may have certain added features installed, such
as a telecoil, a small magnetic coil that makes it easier to hear
conversations over the telephone. ITE aids usually are not worn by young
children because the casings need to be replaced often as the ear grows.
-
Canal aids fit into the ear canal and
are available in two styles. The in-the-canal (ITC) hearing aid is made
to fit the size and shape of a person’s ear canal. A completely-in-canal
(CIC) hearing aid is nearly hidden in the ear canal. Both types are used
for mild to moderately severe hearing loss.
Because they are small, canal aids may be difficult for a person to
adjust and remove. In addition, canal aids have less space available for
batteries and additional devices, such as a telecoil. They usually are
not recommended for young children or for people with severe to profound
hearing loss because their reduced size limits their power and volume.
Top
Do all hearing aids work the same way?
Hearing aids work differently depending on the electronics
used. The two main types of electronics are analog and digital.
Analog aids convert sound waves into
electrical signals, which are amplified. Analog/adjustable hearing aids
are custom built to meet the needs of each user. The aid is programmed by
the manufacturer according to the specifications recommended by your
audiologist. Analog/programmable hearing aids have more than one program
or setting. An audiologist can program the aid using a computer, and the
user can change the program for different listening environments—from a
small, quiet room to a crowded restaurant to large, open areas, such as a
theater or stadium. Analog/programmable circuitry can be used in all types
of hearing aids. Analog aids usually are less expensive than digital aids.
Digital aids convert sound waves into
numerical codes, similar to the binary code of a computer, before
amplifying them. Because the code also includes information about a
sound’s pitch or loudness, the aid can be specially programmed to amplify
some frequencies more than others. Digital circuitry gives an audiologist
more flexibility in adjusting the aid to a user’s needs and to certain
listening environments. These aids also can be programmed to focus on
sounds coming from a specific direction. Digital circuitry can be used in
all types of hearing aids.
Top
Which hearing aid will work best for me?
The hearing aid that will work best for you depends on the
kind and severity of your hearing loss. If you have a hearing loss in both
of your ears, two hearing aids are generally recommended because two aids
provide a more natural signal to the brain. Hearing in both ears also will
help you understand speech and locate where the sound is coming from.
You and your audiologist should select a hearing aid that
best suits your needs and lifestyle. Price is also a key consideration
because hearing aids range from hundreds to several thousand dollars.
Similar to other equipment purchases, style and features affect cost.
However, don’t use price alone to determine the best hearing aid for you.
Just because one hearing aid is more expensive than another does not
necessarily mean that it will better suit your needs.
A hearing aid will not restore your normal hearing. With
practice, however, a hearing aid will increase your awareness of sounds
and their sources. You will want to wear your hearing aid regularly, so
select one that is convenient and easy for you to use. Other features to
consider include parts or services covered by the warranty, estimated
schedule and costs for maintenance and repair, options and upgrade
opportunities, and the hearing aid company’s reputation for quality and
customer service.
Top
What questions should I ask before buying a
hearing aid?
Before you buy a hearing aid, ask your audiologist these
important questions:
-
What features would be most useful to me?
-
What is the total cost of the hearing aid? Do the
benefits of newer technologies outweigh the higher costs?
-
Is there a trial period to test the hearing aids? (Most
manufacturers allow a 30- to 60-day trial period during which aids can
be returned for a refund.) What fees are nonrefundable if the aids are
returned after the trial period?
-
How long is the warranty? Can it be extended? Does the
warranty cover future maintenance and repairs?
-
Can the audiologist make adjustments and provide
servicing and minor repairs? Will loaner aids be provided when repairs
are needed?
-
What instruction does the audiologist provide?
Top
How can I adjust to my hearing aid?
Hearing aids take time and patience to use successfully.
Wearing your aids regularly will help you adjust to them.
Become familiar with your hearing aid’s features. With
your audiologist present, practice putting in and taking out the aid,
cleaning it, identifying right and left aids, and replacing the batteries.
Ask how to test it in listening environments where you have problems with
hearing. Learn to adjust the aid’s volume and to program it for sounds
that are too loud or too soft. Work with your audiologist until you are
comfortable and satisfied.
You may experience some of the following problems as you
adjust to wearing your new aid.
-
My hearing aid feels uncomfortable.
Some individuals may find a hearing aid to be slightly uncomfortable at
first. Ask your audiologist how long you should wear your hearing aid
while you are adjusting to it.
-
My voice sounds too loud. The
“plugged-up” sensation that causes a hearing aid user’s voice to
sound louder inside the head is called the occlusion effect, and it is
very common for new hearing
aid users. Check with your audiologist to see if a correction is
possible. Most individuals get used to
this effect over time.
-
I get feedback from my hearing aid. A
whistling sound can be caused by a hearing aid that does not fit or work
well or is clogged by earwax or fluid. See your audiologist for
adjustments.
-
I hear background noise. A hearing aid
does not completely separate the sounds you want to hear from the ones
you do not want to hear. Sometimes, however, the hearing aid may need to
be adjusted. Talk with your audiologist.
-
I hear a buzzing sound when I use my cell phone.
Some people who wear hearing aids or have implanted hearing
devices experience problems with the radio frequency interference caused
by digital cell phones. Both hearing aids and cell phones are improving,
however, so these problems are occurring less often. When you are being
fitted for a new hearing aid, take your cell phone with you to see if it
will work well with the aid.
Top
How can I care for my hearing aid?
Proper maintenance and care will extend the life of your hearing aid. Make
it a habit to:
-
Keep hearing aids away from heat and moisture.
-
Clean hearing aids as instructed. Earwax and ear
drainage can damage a hearing aid.
-
Avoid using hairspray or other hair care products while
wearing hearing aids.
-
Turn off hearing aids when they are not in use.
-
Replace dead batteries immediately.
-
Keep replacement batteries and small aids away from
children and pets.
Top
Are new types of aids available?
Although they work differently than the hearing aids
described above, implantable hearing aids are designed to help increase
the transmission of sound vibrations entering the inner ear. A middle ear
implant (MEI) is a small device attached to one of the bones of the middle
ear. Rather than amplifying the sound traveling to the eardrum, an MEI
moves these bones directly. Both techniques have the net result of
strengthening sound vibrations entering the inner ear so that they can be
detected by individuals with sensorineural hearing loss.
A bone-anchored hearing aid (BAHA) is a small device that
attaches to the bone behind the ear. The device transmits sound vibrations
directly to the inner ear through the skull, bypassing the middle ear.
BAHAs are generally used by individuals with middle ear problems or
deafness in one ear. Because surgery is required to implant either of
these devices, many hearing specialists feel that the benefits may not
outweigh the risks.
Top
Can I obtain financial assistance for a hearing
aid?
Hearing aids are generally not covered by health insurance
companies, although some do. For eligible children and young adults ages
21 and under, Medicaid will pay for the diagnosis and treatment of hearing
loss, including hearing aids, under the Early and Periodic Screening,
Diagnostic, and Treatment (EPSDT) service. Also, children may be covered
by their state’s early intervention program or State Children’s Health
Insurance Program (SCHIP).
Medicare does not cover hearing aids for adults; however,
diagnostic evaluations are covered if they are ordered by a physician for
the purpose of assisting the physician in developing a treatment plan.
Since Medicare has declared the BAHA a prosthetic device and not a hearing
aid, Medicare will cover the BAHA if other coverage policies are met.
Some nonprofit organizations provide financial assistance
for hearing aids, while others may help provide used or refurbished aids.
Contact the National Institute on Deafness and Other Communication
Disorders' (NIDCD's) Information Clearinghouse with questions about
organizations that offer financial assistance for hearing aids.
Top
What research is being done on hearing aids?
Researchers are looking at ways to apply new signal
processing strategies to the design of hearing aids. Signal processing is
the method used to modify normal sound waves into amplified sound that is
the best possible match to the remaining hearing for a hearing aid user.
NIDCD-funded researchers also are studying how hearing aids can enhance
speech signals to improve understanding.
In addition, researchers are investigating the use of
computer-aided technology to design and manufacture better hearing aids.
Researchers also are seeking ways to improve sound transmission and to
reduce noise interference, feedback, and the occlusion effect. Additional
studies focus on the best ways to select and fit hearing aids in children
and other groups whose hearing ability is hard to test.
Another promising research focus is to use lessons learned
from animal models to design better microphones for hearing aids. NIDCD-supported
scientists are studying the tiny fly
Ormia ochracea because its
ear structure allows the fly to determine the source of a sound easily.
Scientists are using the fly’s ear structure as a model for designing
miniature directional microphones for hearing aids. These microphones
amplify the sound coming from a particular direction (usually the
direction a person is facing), but not the sounds that arrive from other
directions. Directional microphones hold great promise for making it
easier for people to hear a single conversation, even when surrounded by
other noises and voices.
Where can I find more information?
NIDCD maintains a directory of organizations that can
answer questions and provide printed or electronic information on hearing
aids. Please see the list of organizations at
www.nidcd.nih.gov/directory.
Use the following keywords to help you search for
organizations that are relevant to hearing aids:
For more information, additional addresses
and phone numbers, or a printed list of organizations, contact:
NIDCD Information Clearinghouse
1 Communication Avenue
Bethesda, MD 20892-3456
Toll-free Voice: (800) 241-1044
Toll-free TTY: (800) 241-1055
Fax: (301) 770-8977
E-mail: nidcdinfo@nidcd.nih.gov
NIH Pub. No. 99-4340
Updated April 2007