Hearing aids are devices that amplify sound to make hearing easier for those
with hearing difficulties.
Hearing aids are designed to compensate for hearing loss caused by parts of the
hearing system that are not working effectively. Deficits may affect all sounds
or be limited to specific sounds.
Modern electronic hearing aids use a microphone or an array of microphones to
detect sounds. The sounds are coded into a digital representation and are then
filtered to best compensate for the hearing loss. Filtered sounds are then
produced by a speaker and directed into the ear canal to enhance the sound sent
to the eardrum and beyond.
Hearing aids are most effective at assisting mild, moderate or severe hearing
loss caused by limitations in the transmission of sound through the eardrum and
middle ear hearing bones (known as a conductive hearing loss) or reduced
function of inner ear sensory cells called outer hair cells (known as a sensory
hearing loss).
Hearing aids although usually useful are typically not as effective as cochlear
implants for assisting very severe or profound hearing losses.
Hearing aids can also provide some benefit for hearing problems caused by damage
to the hearing nerve or brain.
Hearing aids come in many different shapes, sizes and colours to suit different
needs and preferences. Usually hearing aids can be designed to be smallest when
they provide assistance for mild or moderate hearing loss.
A common misconception is that the use hearing aids is a sign of old age and
should be avoided for as long as possible. This is unfortunate as:
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Hearing aids are used by people of all ages
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Studies of the appearance of adults with visible hearing aids shows that
perceived age is not significantly increased
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Experiencing regular hearing difficulties (because hearing aids are not being
used) can make people seem older!
Being able to hear with both ears (binaural hearing) is at least as important as
being able to see with both eyes.
If you only use one hearing aid when significant hearing loss is present in both
ears there is a risk of auditory deprivation. This is when the brain gradually
loses some of its ability to process information from the unaided ear because
of a long term lack of sound stimulation. Using two hearing aids minimises this
risk.
Most hearing loss affects both ears therefore the majority of people with
hearing loss are good candidates for two hearing aids. In New Zealand over 85%
of suitable new hearing aid users opt for two hearing aids.
If cost is an important factor in your decision then it may be best to get two
less costly hearing aids than one that has a higher price. Important benefits
of binaural hearing (or use of two hearing aids) are:
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You get the best ability to determine where sounds are coming from
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Understanding speech in noisy surroundings is easier for you
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Your risk of auditory deprivation is greatly reduced
The sound picture you experience will be fuller and more comfortable
Digital Hearing Aids
Over 90% of new hearing aids are digital and many use computer processing to
reduce non-speech background noise
Directional Microphones
Hearing aids with two microphone entry points or two or three microphones can be
used to enhance sounds from particular directions. Directional microphones are
typically used to help people concentrate their hearing on a particular
conversation in the presence of background noise or when in a group of people.
A range of different hearing aid styles ands sizes are available with
directional microphones
FM System
An FM System is a device that transmits sound wirelessly from a transmitter
(placed near the source of the desired sound) to a receiver that passes the
sound to the user often via hearing aids. FM Systems are typically used to help
hearing impaired children hear the teacher in a classroom environment or by
hearing impaired adults in seminar or meeting situations.
Remote Controls
Remote Controls are able to control the specific functions of hearing aids such
as adjusting the volume or changing to a different listening programme used for
a different hearing environment.
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