What is a hearing aid?
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 better in both quiet and noisy situations, and to hear sounds that they have been missing.
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. Most modern hearing aids
contain digital technology. Please see "Do all hearing aids work the same way?" for a discussion on digital versus
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
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, hearing aid
benefit may be limited and appropriate hearing aid devices may be recommended.
Some individuals with conductive hearing loss (a loss occurring from the middle ear) may also benefit from hearing
aids. Patients with conductive losses who opt not to have surgery often do very well with hearing aids.
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 a hearing instrument specialist. A
hearing instrument specialist 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. At the appointment, the hearing Instrument specialist
will review you
r hearing test completely to help you understand what type of hearing loss is present, and what the
options for remediation include. If the identified hearing loss can be treated medically, an appropriate referral will be
made to either a primary care physician or an
otolaryngologist. An otolaryngologist is a physician who specializes
in ear, nose, throat disorders and surgeries and will investigate the cause of the hearing loss.
Are there different styles of hearing aids?
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. The ear mold may be custom made to the ear or non-custom depending on the degree of hearing loss.
All levels of technology can fit into this style.
Receiver in the canal, also referred to as a
receiver in-the-ear instrument. Small, open-fit aids sit completely
behind the ear, with only a narrow tube inserted into the ear canal, enabling the canal to remain open. In addition,
some people may prefer the open-fit hearing aid because their perception of their voice does not sound "plugged up'
and sounds more natural. All level of technology can fit into this style, including directional microphones.
Custom aids, are custom made to the shape of your ear. They come in different sizes based upon the amount of
volume necessary for your level of hearing loss. All levels of technology are available in all sizes but some sizes
may be limited in available features based on to the size of the ear.
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.
• In the canal (ITC) hearing aids fit into the bowl of the ear and are used for mild to moderately severe hearing loss.
• Some ITE and ITC aids may have certain added features installed, such as a telecoil. A
telecoil is a small
magnetic coil that allows users to receive sound through the circuitry of the hearing aid, rather than through its
microphone. This makes it easier to hear conversations over the telephone. A telecoil also helps people hear in
public facilities that have installed special sound systems, called induction loop systems. Induction loop systems
can be found in many churches, schools, airports, and auditoriums.
Custom hearing aids are usually not worn by
young children because the casings need to be replaced often as the ear grows.
Completely-in-canal (CIC) hearing aid is nearly hidden in the ear canal. These are used for mild to moderately
severe hearing loss. Because they are small,
CIC aids may be difficult for a person to adjust and remove. In
addition, they have less space available for batteries and additional devices, such as a telecoil and directional
microphone. 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.
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 aids convert soundwaves 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 a hearing specialist more
flexibility in adjusting the aid to a user’s needs and to certain listening environments. Digital circuitry gives the
patient more flexibility by being able to choose from automatic hearing aids, manual hearing aids or both. These
aids also can be programmed to focus on sounds coming from a specific direction. Background noise is also
processed by the hearing instrument. This makes noisy environments more comfortable for the wearer, and with
some models gives the wearer an improved signal to noise ratio and enables speech to be heard better. Digital
circuitry can be used in all types of hearing aids.
Analog aids convert soundwaves 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 hearing specialist. Analog/programmable hearing aids have more than one
program or setting. A hearing specialist 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, but many
manufacturers are phasing out this product choice.
Which hearing aid will work best for me?
You and your hearing instrument specialist should select a hearing aid that best suits your needs and lifestyle. 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
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.
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, and the hearing aid company's reputation for quality and
What questions should I ask before buying a hearing aid?
Before you buy a hearing aid, ask your
hearing instrument specialist 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 hearing instrument specialist make adjustments and provide servicing and minor repairs? Will loaner aids
be provided when repairs are needed?
• What instruction does the
hearing specialist provide?
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 hearing instrument specialist 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 hearing instrument specialist 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.
Many people when getting new hearing aids will wear the aid in increasing amounts of time the first couple of days.
The goal is to be able to wear your aids eight to twelve or more hours a day. If the aid/mold is uncomfortable, then in
office modifications can typically be performed.
• 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. Most individuals get
used to this effect over time but a programming adjustment may need to be done.
• 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. Many digital hearing instruments have feedback managers that can be utilized
to minimize feedback.
• 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. Many hearing aids have
different strengths of noise suppression systems that can easily be adjusted on the computer by the hearing
• 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 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. Some hearing aids with manual
override capability can have a special phone program placed in to the device for talking on the telephone. New digital
technology hearing instruments are compatible with Bluetooth wireless technology. This is accomplished by
wearing an ancillary product around your neck that a Bluetooth cell phone pairs with wirelessly. This in turn will
allow for hands free hearing through both hearing aids.
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 all aids away from children and pets.
• Use drying systems as needed to keep moisture buildup at a minimum.
Are new types of aids available?
Receiver-in-the-ear aids are the latest in hearing aids. They allow for a nice small unit to be placed behind the ear
with a small wire tip being placed in the ear canal. For many individuals these aids meet aesthetic expectations
while also meeting functionality needs. These aids tend to give a more natural sound quality to the users voice.
Bluetooth compatible hearing aids. Hearing aids at all price ranges can work with hands free Bluetooth devices
that are worn around the neck. These assist in hearing the cell phone and television better.
Middle ear implants, (
MEI), work differently than the hearing aids described above. A middle ear implant 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. This results in strengthening sound vibrations entering the inner ear so that they
can be detected. Surgery is required and a thorough consultation with an otolaryngologist to implant the device.
• 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. Surgery and a consultation with an
otolaryngologist is required to implant this device.
Can I obtain financial assistance for a hearing aid?
Hearing aids are generally not covered by health insurance companies, although some do. Financing is usually
available. Heritage Hearing Care of New England contracts with numerous insurance companies. Please check with
us and we would be happy to verify your benefits. If no benefits are offered we offer our patients Care Credit payment
plans including some interest free and extended pay options.
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 best suits the hearing aid
user. NIDCD-funded researchers also are studying how hearing aids can enhance speech signals to improve
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
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.