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How do we hear?
An amazing
natural amplifier
2013
How does the ear work?
T
he human ear is an amazing piece of evolution. Over thousands of years
we have developed the ability to collect sound, apply directional focus and
separate out what important to us, all at the same time. The diagram shown
opposite labels the important parts of the ear. The route that sound takes on its
way to the brain is fascinating.
The outer ear is not just there to hold on your
glasses, it actually collects sound from the front
and directs it down your ear canal. The shape of
the outer ear is thought to amplify frequencies of
sound that would have been early warning signs,
such as twigs snapping. After all, you’ll hear your
enemies approach before you see them!
Once inside the ear canal, sound should make its
way round the bends to the ear drum. Unlike the
diagram, your ear canal is actually a tortuous dog
leg shape to prevent foreign objects being pushed
down and causing damage.
Sound will then hit the ear drum which is a small
piece of skin and cartilage about the size of a 5c
piece and one millimetre thick. The ear drum will
absorb sound energy and move according to the
sound level and frequency. These vibrations are
then passed on to the middle ear mechanism;
the hammer, the anvil and the stirrup. These
three smallest bones in the body effectively
act as a mechanical amplifier or lever to pass
sound vibrations on to the inner ear. These bones
are found inside the middle ear cavity which
is connected to the back of your throat via the
Eustachian Tube.
The Stirrup bone is attached to a footplate which
is a door to the inner ear. Your inner ear contains
fluids vital to the transmission of sound energy
to your brain and waves are created within this
fluid by movement of the Stapedial footplate.
Tiny sensory hair cells within the inner ear detect
the amplitude of these waves and turn that into
electrical impulses to the brain to tell you that
you have heard something.
Similar hair cells and fluid are found inside the
semi-circular canals to help you know which way
up you are. Both are connected, and it is not
uncommon for people to have problems with both
their hearing and balance as a result of infection
(also known as labyrinthitis).
All this happens instantaneously. Nerve bundles
within your brain stem combine information from
both sides to help you understand what you have
heard and what direction it came from. With
such a complex part of your body it is easy to
understand why so many people have difficulty
hearing in some or all situations.
HEARING AWARENESS
Hearing awareness plays a vital part in
helping us to lead a healthy lifestyle for a
long and enjoyable life. How do we hear? is
one of a series of short, handy booklets full
of useful tips and pointers on how to make
sure you get the most out of your hearing.
Other booklets
in this series include:
2013
• What is Audiology?
• What is Tinnitus?
• How can we protect against noise?
The human ear – an amazing piece of evolution
Inner Ear
Ear Canal
Middle Ear
Eardrum
Pinna
Eustachian
Tube
What can you do?
A Hearing Aid Dispenser can
assess the level of your hearing.
If you are concerned about your ears or your
hearing then one of your options is to talk to a
Hearing Aid Dispenser. If they find a condition
that can be treated medically, then they are
ethically obliged to refer you to your G.P.
In many cases however there is little wrong
with the ears. Rather, they just don’t function
as well as they used to. Here again a Hearing
Aid Dispenser can help by assessing the
level of your hearing and helping you decide
what you want to do about it. If a Hearing
Aid Dispenser finds that you have a degree
of hearing loss that could be helped by
amplification then they will advise you of
what’s available. This will include referral to
the Health Board, assistive listening devices
and a range of state of the art hearing
instruments from Hidden Hearing.
Hearing aids have come a long way since
the first transistor sets worn on the body.
They have even developed much further than
the ‘beige banana’ that many people often
associate with hearing aids prescribed by the
Health Board.
What can go wrong?
With such a complicated mechanism there are frequent problems with people’s
ears. Some of these are temporary conditions which can be helped with
medical intervention, and some are more permanent where only amplification
will improve listening. Common problems and symptoms will include:
Wax
Perforated ear drum
Ear wax is a naturally occurring substance in
the ear canal. It’s actually good for your ears
helping to keep the skin healthy and helping
prevent infection at the same time. Some
people suffer from excessive ear wax and
this can only be reduced by use of drops or
irrigation. Wax rarely causes hearing loss and
it can interfere with a hearing test or the use
of a hearing aid. At Hidden Hearing we can
offer a free service to check the health of your
ear canals and identify excessive ear wax.
• The ear drum is a small and fragile piece of
our body. It can be damaged in different ways
and the most common ways are infection,
trauma and pressure.
Infection
Bacteria can cause infection in any part
of the ear and is commonly associated
with inflammation and discomfort. When
an infection is suspected, the advice of a
healthcare professional should be sought
who may recommend the use of antibiotics.
If an infection is discovered by a Hearing Aid
Dispenser, it is likely that a hearing test is
recommended once the infection has cleared
up.
• If infection builds up in the middle ear it
can reach the point where it bursts through
the ear drum. Once the infection has cleared
up, it is likely that the ear drum will heal up.
Long term or recurring ear infections can
cause permanent damage to the ear drum and
may result in a hearing loss.
• Trauma simply means physical damage and
this can be as a result of a blow to the head
or something being pushed into the ear canal.
If it’s only a small tear, again the ear drum
should heal itself with little or no lasting
problems.
• If we are exposed to extremes of pressure
(e.g. diving) it is possible that our ear drums
may become damaged because the difference
in pressure between the outside and our
middle ears becomes too great. Again, as long
as the damage is not too severe, the ear drum
can heal.
• Where the perforation of an ear does not
heal naturally it is possible that a small
operation is recommended to patch the hole.
• If you believe that you have a perforated ear
drum then it is advisable to have a hearing
test to see if it is affecting your ability to hear.
Glue ear
Following an ear infection it is possible for the
middle ear cavity to become congested with
mucosal type fluid. The presence of this fluid
can impair the performance of the hearing,
and relief is sought by use of decongestants
and in more severe cases the insertion of
grommets. A grommet is a tiny plastic tube
that is inserted into the ear drum to relieve
the pressure built up in the middle ear cavity.
The unique design of the grommet means that
it should be pushed once the ear drum heals
and lost through every day ablutions (it’s only
1.5mm in diameter!).
Otosclerosis
A condition that is essentially an ossification
of the middle ear mechanism can also be
identified as otosclerosis. This slows down the
middle ear mechanism and can result in a loss
of hearing. The condition is more prevalent
in women and can sometimes lead to an
operation called a stapedectomy. This complex
operation replaces the stapes bone with a
prosthesis.
Labyrinthitis
An infection of the inner ear can
be called labyrinthitis and will
cause dizziness and potential loss
of hearing. Once the infection has
been treated the aim is to restore
the performance of the inner ear.
Noise damage
Excessive noise levels over a long period of
time will lead to permanent hearing loss.
It can be surprising how low those sound
levels might be and recent Health & Safety
advice says that even those working in noisy
environments of 85dB or more should use
hearing protection. This means that we are not
only talking about people who work in heavy
industry, but also anyone working in bars,
concert venues and building. Noise damaged
hearing loss is irreversible, and will lead to the
affected person losing the ability to hear high
frequency sounds.
Presbyacusis
Presbyacusis (from Greek presbys ‘elder’ +
akousis ‘hearing’), or age-related hearing
loss, is the cumulative effect of aging on
hearing. As we get older, one of the parts of
our body that begins to deteriorate is the inner
ear. This can be revealed by a hearing test
and unfortunately is irreversible. The good
news is that presbyacusis hearing loss is the
most common and there are many amplified
products on the market that have been
designed specifically to help with this type of
hearing loss.
There are many types of hearing loss, and this
is not all of them. If you have any concerns
about your hearing then seek the advice of a
Hearing Aid Dispenser. They will tell you if you
need to consult your G.P. for medical attention
and whether anything can
be done to improve
your hearing.
The power of technology to help
Today’s hearing aids are a quantum leap forward from 20th century technology
and miniaturization of digital technology allows for incredibly discrete devices.
Here are some of the latest developments and how they can help you hear better:
Digital
99% of all hearing aids prescribed today are
digital. This means that hearing aids now
use complex digital processors to manipulate
their amplification to a level which best suits
the wearer. A Hearing Aid Dispenser will
use dedicated software developed by the
manufacturer to program the hearing aids
according to the results of your hearing test
results. Annual check up appointments mean
that the hearing aids can be adjusted again if
your hearing changes.
Directional Microphones
Most hearing aids are now fitted with directional
microphones. The benefit of these is that,
as the name suggests, they can be forward
focusing. This does not mean that other
background sounds are eliminated as this
would be unnatural. Rather the hearing aid
can improve the ability to hear whatever you
are looking at. An important point here is that
where possible, the directional ability works
best where hearing aids can be used in both
ears.
Wireless
One of the latest innovations in technology is
the ability of hearing aids to be able to talk to
each other and to additional wireless devices.
Different products use different types of
wireless technology including Bluetooth. The
main benefits are that the wearer of the hearing
aid system can listen directly to television,
telephones or remote controls without any
wired connections. More intelligent versions of
these hearing aids also work in pairs to make
sure that the sound quality delivered to the
ear on both sides is balanced regardless of the
listening environment.
What are the barriers to
using Hearing Aids?
Invisible in the Canal
The cosmetic design of hearing aids is often
led by people’s desire for them to be discrete.
Manufacturers have now developed a tiny
hearing aid that can be made to fit deep inside
the ear canal and effectively be invisible once
in place. There are a few limitations on the
suitability of such a product, and the anatomy
of individual ear canals must be taken into
account along with the hearing test results.
A consultation with a Registered
Hearing Aid Dispenser will
result in quality advice about
what is right for you.
These are just some of the more recent and
popular advances in hearing aid technology,
and there are plenty of others. When you buy
a hearing aid system you will have access
to literally hundreds of different styles and
technologies. A consultation with a Registered
Hearing Aid Dispenser will result in quality
advice about what is right for you.
“At least four million people who
don’t have hearing aids would
benefit from using them.”
This statistic is taken from the Action on
Hearing Loss (formerly R.N.I.D.) website and
demonstrates that there are clearly barriers
even today to using modern hearing systems.
One possibility is that people just don’t
realise that their hearing is impaired or what
to do about it. For most of us, hearing loss is
a result of the ageing process and happens
slowly. Barely changing day by day, it is often
those around us who notice first.
Secondly, we don’t all know what to do if
we want to have our hearing tested. In many
cases people believe that their G.P. is the
person to speak to about a hearing test, and
unfortunately further research shows that over
40% of patients are NOT referred for a hearing
test. Another view is that wearing hearing aids
will in some way make us appear old or infirm.
In fact, seeking the help of good quality
amplification can help you feel more socially
active and able to participate in conversation
with friends and family. A hearing loss is
always more noticeable than a hearing aid.
Finally, if you really don’t want to be seen to
be wearing a hearing aid, there is now a range
of hearing aids that are invisible once they are
in the ear. The tiny devices are comfortable
to wear and easy to use with some of the
most sophisticated digital technology on the
market today. As part of Hidden Hearing’s
Hearing Awareness initiative we would like
to see the stigma of hearing aids eradicated.
It is believed that in the future hearing aids
will become ‘Communication Devices’ with
applications for those of us even without
hearing loss.
Your FREE HIDDEN HEARING hearing assessment
At Hidden Hearing we aim to improve the quality of your hearing and
most importantly your communication with your family and friends.
Your hearing health is vitally important with poor hearing affecting your
personal relationships, quality of life, and even your ability to go about a
normal day.
With over 27 years of providing hearing health care, our professional
team provides a range of hearing services from hearing assessments to
hearing aids to help you get your hearing back on track. So you can enjoy
the life you want to live!
Don’t delay -
make an appointment for your
FREE HIDDEN HEARING
hearing assessment today.
Call us on:
FREEPHONE 1800 370 000
or visit our website:
www.hearingawareness.ie
“1 in 6 people suffer from some
degree of hearing loss.
I recommend that anyone who is
concerned about their hearing should
not delay in having it checked.”
Dr. Nina Byrnes - MRN19905
Hidden Hearing’s Medical Advisor