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Assistive Technology Project
Presented By: Rose Aldan
Hearing Aid
How Your Ear Works
• An auditory wonder
• Your ears appear to be relatively simple
structures. But they are, in fact, only part
of the complex auditory system —
passageways, vibrating structures, nerves
and specialized areas of the brain that
work together to gather and interpret
sound.
• In people with normal hearing, the ears
can detect a child's whisper or a crack of
thunder, the single call of a songbird or
the entire range of instruments in an
orchestra.
How You Hear
The ear is made up of three primary parts: the outer
ear, middle ear and inner ear. Each section is
composed of structures that play distinct roles in the
process of converting sound waves into signals that
go to the brain.
Outer Ear
The outer ear is
composed of the visible
part of the ear (pinna),
the ear canal and the
eardrum. The cup-shaped
pinna (PIN-uh) gathers
sound waves from the
environment and directs
them into the ear canal.
When a sound wave
strikes the taut, but
somewhat flexible
eardrum (tympanic
membrane), the eardrum
vibrates.
The middle ear is an airfilled cavity that holds a
chain of three bones: the
hammer, anvil and stirrup.
The middle ear is
connected to the back of
your nose and upper part
of your throat by a
narrow channel called the
auditory tube, or
eustachian tube. The tube
opens and closes at the
throat-end to refresh the
air in the middle ear, drain
fluids and equalize
pressure in the ear. Equal
pressure on both sides of
the eardrum is important
for normal vibration of
the eardrum.
Middle Ear
Bones of the Middle Ear
The middle ear contains three tiny bones, including the:
-Hammer (malleus), which is attached to eardrum.
-Anvil (incus), which is in the middle of the chain of bones.
-Stirrup (stapes), which is attached to the oval window, the membrane-covered
opening to the inner ear.
The vibration of the eardrum triggers a chain of vibrations through the bones.
Because of differences in the size, shape and position of the three bones, the force
of the vibration increases by the time it reaches the inner ear. This increase in force
is necessary to transfer the energy of the sound wave to the fluid of the inner ear.
Inner Ear
The inner ear contains a
group of interconnected,
fluid-filled chambers. The
snail-shaped chamber,
called the cochlea (KOK-leuh), plays a role in hearing.
Sound vibrations from the
bones of the middle ear are
transferred to the fluids of
the cochlea. Tiny sensors
(hair cells) lining the
cochlea convert the
vibrations into electrical
impulses that are
transmitted along the
auditory nerve to your
brain.
The other fluid-filled
chambers of the inner
ear include three tubes
called the semicircular
canals (vestibular
labyrinth). Hair cells in
the semicircular canals
detect the motion of the
fluids when you move in
any direction. They
convert the motion into
electrical signals that are
transmitted along the
vestibular nerve to the
brain. This sensory
information enables you
to maintain your sense of
balance.
Inner Ear
Electrical impulses travel
along the auditory nerve
and pass through several
information-processing
centers. Signals from the
right ear travel to the
auditory cortex located in
the temporal lobe on the
left side of the brain. Signals
from the left ear travel to
the right auditory cortex.
The auditory cortices sort,
process, interpret and file
information about the
sound. The comparison and
analysis of the all the signals
that reach the brain enable
you to detect certain sounds
and suppress other sounds
as background noise.
Traveling to the Brain
Hearing Loss
In 90 percent of cases, hearing loss results from damage to the hair cells in the
cochlea, the National Institutes of Health says. This is called "sensorineural
hearing loss." The damage can occur as a result of genetic factors, aging, illness,
certain medications and exposure to loud noise. When the hair cells in the inner
ear are damaged, electrical signals are not transmitted as effectively. This causes
impaired hearing. Sensorineural hearing loss is the main type of hearing loss that
can be "reversed" with a hearing aid.
What is a Hearing Aid and How does it Work?
All hearing aids consist of a
microphone, an amplifier, a
miniature loudspeaker, or
receiver, and a tiny battery.
The microphone catches
sounds and transforms them
into electrical impulses. The
amplifier modulates the
electrical signals. Finally, the
receiver converts the
amplified signals into
sounds and transfers them
into your ear canal.
Although the basic
components of all hearing
aids are the same, hearing
aids differ in design,
amplification technology
and special features.
Why Wear A Hearing Aid
Hearing problems might restrict your daily activities. You might have trouble
communicating and following instructions in school or at work. When damage to
the inner ear is the cause of your hearing loss, you don't have to struggle through
life because you can't hear. A properly fitted hearing aid might make sounds easier
to hear. An audiologist or otolaryngologist can help you determine which type of
hearing aid would be best for your condition.
Why People Don’t Wear Hearing Aids
Some people don't want a hearing aid because they think it is too
expensive. Others feel it is embarrassing to wear one because they associate
it with old age, low intelligence or disability. This is odd when you think
about it, as many of the same people happily wear vision aids, such as
contact lenses or glasses. Shunning hearing aids to avoid looking old can be
self-defeating. If you have trouble hearing, your conversation partners might
think of you as old or unfriendly. There is nothing embarrassing about
wearing a hearing aid, and people most likely won't notice as most hearing
aids are so small that they are practically invisible.
Cost
Hearing aids for children
cost between $1,000 and
$4,000 per ear. A few
health insurance
companies will pay for
children hearing aids, but
most do not. Medicaid
will pay for children
hearing aids for those
who qualify.
History of
Hearing Aids
The first hearing aids
were enormous,
horn-shaped
trumpets with a
large, open piece at
one end that
collected sound. The
trumpet gradually
tapered into a thin
tube that funneled
the sound into the
ear.
The development of the modern hearing aid might not have been possible
had it not been for the contributions of two of the greatest inventors of the
late 19th and early 20th centuries. Alexander Graham Bell electronically
amplified sound in his telephone using a carbon microphone and battery -a concept that was adopted by hearing aid manufacturers. In 1886, Thomas
Edison invented the carbon transmitter, which changed sounds into
electrical signals that could travel through wires and be converted back into
sounds. This technology was used in the first hearing aids
History of Hearing Aids
In the 1990s, hearing aids went digital. Sound quality improved and became
more adjustable. Also during this time, programmable hearing aids were
introduced.
At the turn of the 21st century, computer technology made hearing aids
smaller and even more precise, with settings to accommodate virtually every
type of listening environment. The newest generation of hearing aids can
continually adjust themselves to improve sound quality and reduce
background noise.
Types of Hearing Aid’s
How Reliable are Hearing Aid’s
• Reliability and appropriateness are crucial
when your hearing is at stake. Also
remember that some prices include an
evaluation and checkups.
• If they are well cared for, hearing aids
should last for five to seven years. Most of
the problems that send hearing aids in for
repairs are caused by dirt, earwax and oil
from the skin that blocks the microphones
and receivers.
Accessibility in the CNMI
• Commonwealth of the Northern Mariana Islands
Assistive Technology Project
• Department of Public Health
• Marianas Health Services
• Public School System
• Office of Vocational Rehabilitation
• Insurance
Sources
-Google Images
-Department of Public Health
-www.livestrong.com