Download pathologies of the inner ear - NSW Department of Education

LEARNER RESOURCE
Audiometry - Pathologies
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Acknowledgments
TAFE NSW - Community Services, Health, Tourism and Hospitality Division would like
to acknowledge the support and assistance of the following people in the production of this
resource package:
Writer:
Jean Tsembis
Audiologist
TAFE NSW
Based on a learning guide written by Janette Brazel & Jean Tsembis
Project Manager:
Gary Wood
Program Manager
Health and Life Sciences Programs
Enquiries
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Locked Bag No. 6
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Fax: 02-9942 3257
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TABLE OF CONTENTS
INTRODUCTION TO THIS LEARNING RESOURCE ................................................ 1
INTRODUCTION TO PATHOLOGIES OF THE EAR ................................................ 3
SUGGESTED LEARNING RESOURCES ....................................................................... 5
RELEVANT TEXTS ............................................................................................................... 5
RELEVANT INTERNET SITES ................................................................................................ 6
TERMINOLOGY ................................................................................................................ 9
HEARING LOSS PRESENT FROM BIRTH ................................................................ 11
COMMON PHYSICAL ABNORMALITIES OF THE EAR ............................................................ 11
SYNDROMES ..................................................................................................................... 12
PATHOLOGIES OF THE OUTER EAR ....................................................................... 15
The pinna ..................................................................................................................... 15
Perichondritis .............................................................................................................. 15
Otitis externa ............................................................................................................... 15
Occluding cerumen ...................................................................................................... 15
Perforations of the tympanic membrane ..................................................................... 16
THE EFFECT OF PATHOLOGIES OF THE OUTER EAR............................................................. 16
PATHOLOGIES OF THE MIDDLE EAR ..................................................................... 17
Otitis media ................................................................................................................. 17
Cholesteatoma ............................................................................................................. 18
Otosclerosis ................................................................................................................. 18
Ossicular discontinuity ................................................................................................ 19
THE EFFECT OF PATHOLOGIES OF THE MIDDLE EAR ........................................................... 19
PATHOLOGIES OF THE INNER EAR ........................................................................ 21
Meniere’s syndrome .................................................................................................... 21
Meningitis .................................................................................................................... 21
Noise-induced hearing loss ......................................................................................... 22
Acoustic trauma ........................................................................................................... 22
Head trauma ................................................................................................................ 23
Presbycusis .................................................................................................................. 23
Acoustic Schwannoma or Acoustic Neuroma .............................................................. 23
Ototoxic medications ................................................................................................... 24
Large vestibular aqueduct syndrome .......................................................................... 24
Idiopathic sudden hearing loss .................................................................................... 25
THE EFFECTS OF PATHOLOGIES OF THE INNER EAR ............................................................ 25
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PSEUDOHYPOACUSIS .................................................................................................. 27
SUMMARY........................................................................................................................ 29
SUMMARY OF PATHOLOGIES .................................................................................. 31
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INTRODUCTION TO THIS LEARNING RESOURCE
This learning resource deals with some of the pathologies of the ear. This is one of the
recurring themes in the audiometry units of competency that are aligned to the Certificate
IV in Audiometry HLT41302, which is a qualification of the Health Training Package
HLT02. The units of competency that include the theme of pathologies are:
HLTAU1A – Conduct screening hearing tests for children
HLTAU2A – Conduct screening hearing tests for adults
HLTAU3A – Conduct hearing tests assessments
Pathologies of the ear are part of the required knowledge that underpins the
development of competence. This knowledge will help you to understand the results
of hearing assessments and how to communicate with clients about their results and
options for rehabilitation. It will also help you in discussing results with other clinicians
such as audiologists and doctors.
Before starting this learning resource it is expected that you will have completed the
learning resource covering the anatomy of the ear.
In your activities and assessments your teacher can reasonably ask you to:
 explain the meaning of terminology associated with pathologies of the ear
 list the most common pathologies experienced by adults
 list the most common pathologies experienced by children
 describe the most common pathologies
 describe the effects of pathologies.
This learning resource is designed to complement your class or individual learning
activities. You should use this resource as a guide to identify areas of learning. You
MUST use other sources of information to complete this theme. There are many
pathologies and this learning guide provides a brief overview of a small number of them.
Throughout your career it is likely that you will encounter other pathologies. You will
need to be able to access sources of information and understand the terminology used to
describe pathologies.
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INTRODUCTION TO PATHOLOGIES OF THE EAR
Pathology is the study of diseases and disorders and their effect. Many, many
problems can manifest themselves in the ear. Some malfunctions are of a minor,
temporary nature, or can be treated with minimal medical intervention. Other
disturbances to the hearing organ can require surgery or their pathology is irreversible,
ie permanent. A hearing loss can be caused by any number of pathologies at any stage
along the hearing pathway.
Hearing loss can be caused by trauma, infection, tumours and medications. They can
be related to the process of ageing or be congenital. Sometimes they are caused by
environmental factors and sometimes it is not known what causes a hearing loss.
It is the role of a medical practitioner to make a decision about the pathology of
hearing loss. Audiometrists are not medically trained so they cannot make a
judgement about the cause of hearing loss. It is possible that the client comes to your
clinic having already been diagnosed with a particular pathology; however, it is much
more likely that you will not have this information available.
There are a number of specialists that may comment on the pathology of hearing loss.
These include the Ear, Nose and Throat specialist, the paediatrician and the geneticist.
If a client expresses a desire to establish why they have a hearing loss then you should
advise them to speak to their family doctor for more information.
If there is a problem with the ear then it is likely that it will cause some hearing loss.
Whether the hearing loss is temporary or permanent will depend on where in the hearing
mechanism the problem occurs, ie the site of lesion.
The main effect of a hearing loss is on communication. The communication effect of the
hearing loss will depend on when the hearing loss started, the degree of the hearing loss
and how soon habilitation or rehabilitation occurs.
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SUGGESTED LEARNING RESOURCES
There are many textbooks that can help you with this topic. The following textbooks are
all relevant and you may decide to refer to them as you study this topic. You may also like
to access the internet. There are hundreds of internet sites that describe pathologies of the
ear.
Relevant texts
TITLE
AUTHOR
PUB DATE
PUBLISHER
ISBN
Clinical Audiology: An Introduction
Stach, B.A.
1998
Singular Publishing Group Inc, San Diego
156593346X
TITLE
AUTHOR
PUB DATE
PUBLISHER
ISBN
Hearing in Children
Northern, J.L. & Downs, M.P.
5th Edition, 2002
Lippincott Williams & Wilkins, Philadelphia
0683307649
TITLE
AUTHOR
PUB DATE
PUBLISHER
ISBN
Syndrome Identification for Audiology, an Illustrated Pocket Guide
Shprintzen, R.J.
2001
Singular, Thomson Learning
0769300200
TITLE
AUTHOR
PUB DATE
PUBLISHER
ISBN
Syndrome Identification for Speech-Language Pathology, An
Illustrated Pocket Guide
Shprintzen, R.J.
2000
Singular, Thomson Learning
0769300197
TITLE
AUTHOR
PUB DATE
PUBLISHER
ISBN
Handbook of Clinical Audiology
Katz, J. et al.
4th Edition, 1994
Williams & Wilkins, Baltimore. Md.
0683006207
TITLE
AUTHOR
PUB DATE
PUBLISHER
ISBN
Audiology: The Fundamentals.
Bess, F.H. & Humes, L.E.
2nd Edition, 1995
Williams & Wilkins, Baltimore. Md.
0683006207
TITLE
AUTHOR
PUB DATE
PUBLISHER
Introduction to Audiology
Martin, F.N. & Clark, J.G.
8th Edition, 2003
Allyn & Bacon, Boston
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ISBN
0205366414
TITLE
AUTHOR
PUB DATE
PUBLISHER
ISBN
Basic Principles of Audiology Assessment
Hannely, M.
1991
Prentice-Hall, USA
0205135528
TITLE
AUTHOR
PUB DATE
PUBLISHER
ISBN
Audiology
Newby, Hayes.
1992
Prentice-Hall, New York
0130519219
Relevant internet sites
There are many sites on the Internet that you can access using a search engine. As with all
information, you need to cross check a variety of sources to establish its credibility. Many
of the websites will help you to understand aspects of hearing loss from the client’s point
of view. The sites that are listed below were accessed in November 2003. As internet sites
and the information in them change, you may wish to perform your own search.
http://www.vh.org/
Includes useful anatomical information.
http://www.cochlea.org/
Interesting pictures of the affect of some pathologies on the inner ear.
http://www.merck.com/mmpe/sec08.html
Information about pathologies of the ear by site of lesion.
http://reference.allrefer.com/encyclopedia/D/deafness.html
Brief overview of conductive and sensorineural hearing loss.
http://www.rcsullivan.com/www/referenc.htm
This site has many photos of pathologies of the outer ear.
http://www.health.nsw.gov.au/hearing/statewide.html
The website for the NSW neonatal screening for hearing loss program.
http://www.communicationdisorders.net/index.html
This website has a lot of information to do with anatomy and syndromes.
http://www.cleftpals.org.au/
Information about Cleft Lip and Palate by a self-help group.
http://www.sspa.org.au/sspa.htm
The official website of the Short Statured People of Australia.
http://www.retinaaustralia.com.au/AssocConditions.htm
Information about Usher Syndrome.
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http://www.austcharge.com.au/
Information about CHARGE Syndrome.
http://www.aussiedeafkids.com/Phidcoz/causes.html
Links to information about many of the causes of hearing loss
http://pediatrics.about.com/od/childhoodinfections/a/ear_infections.htm
Describes otitis media and its treatment.
http://www.menieres.org/
Information about Menieres Disease.
http://oto.wustl.edu/men/
Information about Menieres Disease.
http://www.methodisthealth.com/otolaryn/presby.htm
Information about many ear conditions.
http://www.hearingconcern.com/factsheets/factsheet_23.htm
Information about presbycusis.
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TERMINOLOGY
There is some terminology that you need to be familiar with before beginning this learning
guide. If you do not know the meaning of the following words take some time now to find
out. You can use a variety of sources such as dictionaries, medical dictionaries or the
internet.
TERM
MEANING
Acquired
Adventitious
Bilateral
Congenital
Habilitation
Hereditary
Iatrogenic
Idiopathic
In situ
In utero
Inherited
Onset
Progressive
Rehabilitation
Site of Lesion
Tinnitus
Trauma
Unilateral
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HEARING LOSS PRESENT FROM BIRTH
Hearing loss that is present from birth is referred to as congenital. There are many causes
of congenital hearing loss some of which are hereditary but many are related to other
factors and for many babies born with a hearing loss there will be no known reason.
Congenital hearing loss can be of any degree and of any configuration. That is, the hearing
loss can be mild, moderate, severe or profound. It may be that only one ear is affected or
there may be a difference between the ears.
About one to three babies out of every thousand are born with a permanent hearing loss.
The hearing loss may remain stable or may become worse over time, so children with
hearing loss are monitored carefully. Some babies have a temporary condition that may
improve over time with or without treatment.
There are Neonatal Hearing Screening Programs in some states of Australia. The New
South Wales Department of Health started the State-wide Infant Screening – Hearing
Program in December 2002. For more information about this you can visit the NSW
neonatal screening for hearing loss program website:
http://www.health.nsw.gov.au/hearing/statewide.html
Any hearing loss can have an impact on the child’s development of speech and language
skills. Therefore, it is considered very important that paediatric audiologists test babies
that do not pass the screening program.
Some babies are born with a syndrome or a malformation that may impact on hearing.
These may or may not affect the baby immediately but these babies will probably be
monitored to make sure that the hearing is not affected.
There are risk factors for hearing loss. These include in utero infections such as rubella,
toxoplasmosis and cytomegalovirus. Some of these have an immediate impact on the
hearing but some do not.
Another risk factor for hearing loss is if a member of the family has a hearing loss that has
no known cause. For example, if the grandfather of the child has a hearing loss that was
present from a young age then it is considered that the child has a family history of hearing
loss. However, if the family member has a hearing loss caused by an environmental factor
or age then it is not considered a family history. For example, if the grandfather has a
hearing loss caused by noise exposure then it is not considered to be family history.
For more information about the causes of hearing loss you can visit this website:
http://www.aussiedeafkids.com/Phidcoz/causes.html
Common physical abnormalities of the ear
Occasionally children are born with some abnormality of the ear. This may be obvious
such as ear tags and pits, microtia and atresia. These are seen easily at birth and these
babies will be asked to go to a paediatric audiology clinic for testing as they may indicate
that a hearing loss exists.
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Some abnormalities of the ear cannot be seen. Mondini and Michel deformity affect the
cochlea and cannot be seen unless special scans are done. You can find more information
about these from many books. One excellent reference for this is Northern, J.L. & Downs,
M.P. (2002) Hearing in Children.
Sometimes a Paediatrician will say that a baby has dysmorphic features. This means that
the baby has unusually shaped features.
Syndromes
There are many syndromes that can include hearing loss. If you have a client with a
particular syndrome it is worthwhile taking the time to find out if hearing loss is
considered a possibility with that syndrome. You should also try to find out what type of
hearing loss is associated with the syndrome and whether it is likely that the hearing loss is
progressive because this will affect how you manage the client’s care. You will find
information from many sources but the following books will give you a starting point:

Northern, J.L. & Downs, M.P. (2002) Hearing in Children.

Shprintzen, R.J. (2001) Syndrome Identification for Audiology, an Illustrated Pocket
Guide

Shprintzen, R.J. (2000) Syndrome Identification for Speech-Language Pathology, An
Illustrated Pocket Guide
Syndromes will affect the ear in different ways. For example, common syndromes that
affect the middle ear include Achondroplasia, Treacher Collins Syndrome, BOR
Syndrome, Cleft Lip/Palate and Down Syndrome. These syndromes may be related to
malformations of the outer or middle ear that cannot be treated surgically or may be related
to fluctuating middle ear problems that can be treated medically.
Some syndromes will effect both the middle and inner ears. For example, Turner
Syndrome, CHARGE Association.
Some syndromes will effect the inner ear and may be progressive: Usher Syndrome;
Waardenburg Syndrome; Marshall Syndrome; Neurofibromatosis Type II.
 Achondroplasia
People with achondroplasia have a skeletal abnormality that means they will be very short
and the head will be large and the arms and legs are short. It is also referred to as
Dwarfism. You can find more information at http://www.sspa.org.au/sspa.htm the official
website of the Short Statured People of Australia.
 Cleft Lip/Palate
Babies born with clefts of the palate and lip are often tested. This is because they are at
risk for hearing loss. This hearing loss may be of a permanent nature or may be related to
middle ear problems. If babies develop middle ear problems at a very young age it is
likely that they will be under the care of an Ear, Nose and Throat Specialist and have their
hearing monitored closely. There is information, photos and links to other websites on the
website http://www.cleftpals.org.au/ that is maintained by The Cleft Lip and Palate
Society, an Australian volunteer, non-profit organisation.
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 CHARGE Association
Information from the Australasian CHARGE Syndrome Association is at
http://www.austcharge.com.au/. The ear is often malformed and there may be a hearing
loss.
 Usher Syndrome
There are a few different types of Usher Syndrome. Hearing loss co-exists with a visual
impairment. The type relates to the severity and onset of the syndrome. Information is
available at http://www.retinaaustralia.com.au/AssocConditions.htm.
 Neurofibromatosis
There are two types of neurofibromatosis. Hearing loss is common in the Type 2. The
hearing loss usually starts after childhood and is related to acoustic neuroma (discussed
later in this Learning guide).
It is not possible to do justice to the topic of syndromes in this learning guide. You should
spend some time exploring ways of obtaining information about syndromes so that if you
are asked to see someone with a syndrome then you will be able to get some idea of the
type of hearing loss associated with the syndrome and whether the hearing loss is
progressive. If you cannot find information about a syndrome you can ask the client or
their caregivers if they know whether there is any hearing loss associated with the
syndrome. The internet, even a Google or Yahoo search often yields quite good and easilyaccessible information about syndromes (as long as you spell it correctly).
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PATHOLOGIES OF THE OUTER EAR
Can pathologies in the outer ear cause significant hearing loss? Generally the answer
is no. The deficit, if any, resulting from an outer ear pathology, is minor and
temporary.
Can pathologies of the outer ear be treated medically? Generally the answer to this is
yes.
The pinna
If the pinna has been damaged through accident or partially removed through surgery,
there is no effect on the ear’s ability to hear. However if the pinna is congenitally
malformed, it may be associated with malformations of other parts of the ear or other
syndromes that cause hearing impairment.
The condition where there is a small or malformed pinna is referred to as microtia. If
the ear canal is very narrow it is called a stenosis of the EAM. If the ear canal doesn’t
exist or is blocked by bone, it is called an atresia of the EAM.
If there is no external auditory meatus sound cannot reach the inner ear as easily and
therefore there will be some hearing loss. The cochlea, however, is usually not
affected.
Perichondritis
This is where there has been damage to the cartilage of the pinna. This can happen
through trauma or infection. It usually results in a malformed pinna that is commonly
referred to as cauliflower ear. If the trauma or infection has not affected any other part
of the ear then it will not cause hearing loss. However, there is a possibility that
whatever has caused the perichondritis has also affected the inner ear and/or middle
ear..
Otitis externa
An infection occurring in the skin of the external auditory canal. Sometimes referred
to as “swimmer’s ear”, otitis externa can be very painful and itchy. It can be treated
with oral (ie, taken by mouth) antibiotics or ear drops. The skin can become quite
swollen and inflamed. The condition is often accompanied by a rise in body
temperature. When the condition is advanced, the tympanic membrane can also
become inflamed and may develop blood blisters on its surface. Usually it is difficult
to assess a person’s hearing with this condition, as the placement of earphones is
painful. However, hearing loss, if present, would usually be minimal and temporary.
Occluding cerumen
Cerumen is the term we use to describe wax. You can use either term but your clients
are more likely to understand the word wax. Cerumen in the ear canal is normal. It is
only when the cerumen blocks the ear canal that it becomes a problem.
Excessive cerumen that is blocking the ear canal can cause some hearing loss
particularly if it is hard and impacted.
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The doctor may need to remove occluding cerumen prior to a hearing assessment to
obtain exact threshold levels. The cerumen can be softened with ear drops that have
been applied over several days and indeed this may be enough for the cerumen to
dislodge itself and move out of the ear canal. Wax drops should be used with caution
and it is best if you advise your client to ask their Doctor’s advice.
Under no circumstances should the client try and remove the cerumen with cotton buds
or other such implements as they can tend to force the cerumen deeper into the ear
canal and may perforate the TM.
Perforations of the tympanic membrane
Holes or perforations may appear in the tympanic membrane through a variety of
incidents. The tympanic membrane may rupture through excessive pressure in the
middle ear cavity or it may be pierced by a foreign object in the ear canal such as a
bobby pin or cotton bud. Sudden pressure in the external auditory canal may also
perforate the tympanic membrane. This is called barotrauma. This pressure may be
caused by something as severe as a blast or by something as simple as clapping a hand
over the ear. Perforations generally heal by themselves over a period of weeks.
However, perforations caused by continuous infections may not heal and surgery may
be required. A tympanoplasty is an operation that involves grafting a piece of skin over
the hole. Providing the perforation heals, hearing should improve once the tympanic
membrane is intact.
The effect of pathologies of the outer ear
Pathologies of the outer ear do not normally cause a permanent hearing problem.
It is very likely medical treatment will be possible, and will restore the hearing.
Hearing loss caused by pathologies of the outer ear is called conductive loss.
The hearing loss caused by pathologies of the outer ear is usually of a mild degree. At
worst, the hearing loss may be of a moderate degree.
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PATHOLOGIES OF THE MIDDLE EAR
How do pathologies in the middle ear affect the conduction of sound through this
section? How significant an impact on hearing levels do they have and are they
temporary or permanent? Generally pathologies in the middle ear are temporary but
many need significant medical treatment for correction. Some pathologies are genetic
and result in a permanent hearing loss of a conductive nature. This may be because the
structures of the middle ear, particularly the ossicles, have not formed properly.
Otitis media
Otitis media is an infection of the middle ear space. It is one of the most common
pathologies of the middle ear, especially in children. Remembering that the middle ear
cavity is lined with mucous membrane, it is easy to understand how the infection
occurs. Any infection of this lining is referred to as otitis media. Usually organisms
gain entry to the middle ear cavity via the Eustachian tube, or through a perforated
tympanic membrane. The lining of the middle ear becomes swollen with the infection.
The infection process may spread rapidly, with the initial appearance of a retracted
tympanic membrane due to interference of the pressure-equalisation function of the
Eustachian tube. Otoscopic inspection may reveal the retracted tympanic membrane
and may also show a red ear due to the area becoming very vascular. If no treatment is
received at this stage suppurative otitis media may result with the production of pus in
the cavity. Pain is usually evident at this stage and elevated temperatures may be
observed.
Treatment for otitis media may include the use of antibiotics. If the condition persists
the middle ear cavity may be cleared of fluid by myringotomy, ie making an incision in
the tympanic membrane. Usually grommets, also called ventilation tubes, are inserted
in the tympanic membrane to aerate the middle ear. This procedure aids the ear in
keeping equal air pressure on both sides of the tympanic membrane. The grommets
may be in position for up to 18 months. There are many different types of grommets
and if necessary there are some that are designed to stay in place (in situ) for longer.
If the condition continues without treatment, rupture of the tympanic membrane may
result. This will generally coincide with relief from the pain. The pus will then seep
into the external auditory meatus. Pus that does not leave the middle ear cavity in this
manner may occupy the mastoid cavity. Mastoiditis may result. Aggressive treatment
is required to treat this condition. If untreated it can lead to very serious complications
including meningitis.
A hearing loss usually occurs with otitis media. The level of hearing loss depends on
the progression of the disease. A return to previous hearing levels is expected after
medical intervention.
There are certain people that are very prone to otitis media. This includes children:
under 8 years of age; with Down Syndrome; with Cleft Palate and Indigenous
Australians.
There are many textbooks that can help you to understand otitis media including Bess, F.H.
& Humes, L.E. (1995) Audiology: The Fundamentals Williams & Wilkins, Baltimore. Md.
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You can also visit the following website for more information on otitis media:
http://pediatrics.about.com/od/childhoodinfections/a/ear_infections.htm
Cholesteatoma
This is a squamous tissue tumour resulting form skin being introduced into the middle
ear cavity. This may occur as a result of a perforated tympanic membrane.
Perforations that occur within the attic, or pars flaccida, of the tympanic membrane are
particularly susceptible to the formation of cholesteatomas. Cholesteamtomas are very
aggressive and can be extremely dangerous. They can spread and may erode parts of
the ear. Secondary infections generally accompany a cholesteatoma. Otorrhea, a
smelly discharge, is common with this condition.
Depending on the cholesteatoma, there may or may not be a hearing loss. It is a
serious medical condition as it can spread. If you ever see a cholesteatoma, and they
are quite rare in adults, you should tell your client to see a doctor IMMEDIATELY.
Surgery is the best option for a favourable outcome to this condition. The surgeon
must ensure all signs of the cholesteatoma are removed, otherwise the condition will
still exist and will recur.
Otosclerosis
This condition refers to the over-calcification within the ossicular chain, causing a
conductive hearing loss. The condition is often hereditary and causes a conductive
hearing impairment. Generally only seen in adults, the condition is progressive and
more aggressive in pregnant or menopausal women due to hormonal changes during
these periods. Otosclerosis involves extra growth of spongy bone, normally around the
stapes. The condition can be unilateral or bilateral. With this bony growth the stapes
footplate becomes fixated to the oval window, unable to impress the vibrations upon it
efficiently. Tinnitus often accompanies the condition. Otoscopic examination will
usually be unremarkable. However the promontory may become quite vascular
emanating a rosy glow that can be seen through the tympanic membrane. This glow is
referred to as the Schwartze sign.
Hearing loss is progressive but the cochlea is usually unaffected.
Another phenomena that occurs with otosclerosis is the paracusis willisii affect. It is
common for hearing impaired clients to mention difficulty in hearing in background
noise. However with hearing losses caused by the middle ear, speech is easier to hear
when there is background noise. This happens because we tend to raise our voices
when in noise but the loss caused by the middle ear is essentially a loss in amplitude.
A person with otosclerosis will enjoy being in surroundings where people talk louder!
Otosclerosis can be treated surgically. The fixated stapes is removed and replaced with
a prosthesis, ie, a plastic piece that acts as a replacement for the stapes. This procedure
is referred to as a stapedectomy.
The hearing loss associated with this condition may be moderate to severe. Surgery
can improve the condition of the middle ear to near-normal status. Surgery is not
always successful and some clients may opt to be fitted with hearing aids.
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Ossicular discontinuity
When a blow or blast to the ear occurs, trauma to the middle ear can result. The
tympanic membrane can be perforated, but the ossicular chain can also be disturbed.
Ossicular discontinuity occurs when there is a break or breaks in the ossicular chain.
The tympanic membrane may also be significantly ruptured, leaving the ossicles
hanging ‘in mid air’, so to speak! Otoscopic inspection may reveal a torn tympanic
membrane and visible ossicles attached to their tendons in the middle ear space. The
accompanying conductive hearing loss is moderately-severe and the middle ear will
need to be repaired surgically. Complete reconstruction of the ossicular chain and
tympanic membrane is difficult and some permanent hearing loss may result.
The effect of pathologies of the middle ear
Pathologies of the middle ear do not normally cause a permanent hearing problem.
However, if there is a congenital malformation of the middle ear it may lead to a
permanent hearing loss.
It is likely medical treatment will be possible which may restore the hearing.
Hearing loss caused by pathologies of the middle ear is called conductive loss.
The hearing loss caused by pathologies of the middle ear may be of a mild or moderate
degree.
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PATHOLOGIES OF THE INNER EAR
The most common type of hearing loss in adults is called sensorineural hearing loss.
Sensorineural hearing loss occurs in the inner ear or along the neural pathway and is
permanent. It most commonly involves permanent damage within the cochlea.
How are sensorineural losses different from conductive losses? A sensorineural
hearing loss will cause a loss of sensitivity to sound but will also cause a loss of
clarity. That is, the person will have discrimination problems.
Common symptoms of sensorineural hearing loss include dizziness, vertigo and
tinnitus.
Meniere’s syndrome
Meniere’s syndrome is sometimes also referred to as Meniere’s disease and
endolymphatic hydrops. Some people make a distinction between these 3 terms.
This disease is typified by a sudden loss of hearing in one ear, of a sensorineural nature
but predominantly in the low frequencies. The hearing loss usually fluctuates until the
condition stabilises. The hearing loss tends to increase in severity and although the
hearing may recover in between episodes there is often some residual hearing loss. The
person is usually left with a permanent hearing loss even after they stop having
episodes.
Violent vertigo and nausea attacks of sudden onset may also accompany Meniere’s
syndrome but different people with experience different degrees of these symptoms.
The condition usually begins with an episode sensation of fullness in one ear,
including vertigo, a dull roaring tinnitus, difficulty with speech discrimination,
sensation of extreme turning in space and vomiting. An episode can last for several
days. An episode (Menieres attack) can occur at any time without warning. Meniere’s
syndrome is thought to originate in the labyrinth and is related to the over-secretion of
endolymph. Pressure builds up in the cochlea duct causing the vertigo. Medical
treatment of Meniere’s syndrome is less than satisfactory as there is no cure and the
client tends to ‘grow out’ of the condition with the attacks becoming less violent and
frequent as time passes. Some treatments limit fluid retention and sodium intake. No
one treatment has significant results hence the development of Meniere’s syndrome
support groups to help clients with this truly debilitating affliction. Nonetheless, clients
should be encouraged to see an Ear Nose and Throat Specialist as certain treatments
can help reduce symptoms and the frequency of attacks.
You should take the time to find out more about Meniere’s syndrome. The Meniere’s
Support Group of NSW maintains a website with links to more information at
http://www.hinet.net.au/~nswmsg/links.htm. You could also look at this website for
additional information: http://oto.wustl.edu/men/.
Meningitis
The meninges are the lining of the brain. Meningitis is an infection of the meninges.
The meninges may become infected with a virus or bacteria. Meningitis has the
potential to result in very serious complications. One of these complications can be a
loss of hearing. The hearing loss can be unilateral (one sided) or bilateral (two sided).
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The loss can be a profound, ie of great significance, sensorineural hearing impairment.
Meningitis is a common cause of permanent acquired hearing loss in children.
Noise Induced Hearing Loss
When the human ear is exposed to excessive noise over a period of time, a hearing loss
can occur. Currently in most states of Australia, excessive noise is described as noise
which is greater than 85dBA over an eight hour period. Hearing loss through noise
injury can occur in two ways. It can be slow and progressive over a period of time or it
can be instantaneous through an acoustic trauma such as a blast.
The term that is usually used with progressive hearing loss associated with noise is
NIHL or Noise Induced Hearing Loss.
It is often characterised by periods of TTS followed by PTS. That is, temporary
threshold shift followed by permanent threshold shift.
The temporary threshold shift will occur when the outer hair cells of the cochlea are
able to recover. Many people experience this after being in a noisy place and will
describe the sensation of feeling like their ears are stuffed with cotton wool. They will
also usually experience tinnitus. It may take the ears up to 16 hours, and sometimes
even longer, to recover. If the ears are continually exposed to excessive noise causing
a TTS then recovery cannot take place and a permanent threshold shift occurs. That is,
a permanent hearing loss.
If the ear is not able to recover from the noise a permanent hearing loss of a
sensorineural nature will develop. The hearing loss is characterised in the initial stages
by normal hearing in the low and mid frequencies with a mild loss occurring in the
high frequencies. As the pathology progresses the high frequencies become more
depressed and the hearing loss spreads to the mid and low frequencies. The shape of
the audiogram for noise injuries is characterised by a ‘noise notch’ configuration. This
is where the greatest point of the hearing loss will occur at either 3000, 4000 or
6000Hz and the hearing will have recovered to some extent at 8000Hz. This gives the
audiometric results a V or notch configuration.
Acoustic Trauma
Hearing loss through noise injury can result in a profound or complete loss through
trauma, although this is uncommon.
So how does the noise damage the inner ear? Remember that our hair cells are
arranged in four rows, ranging from high frequency cells at the basal (oval window)
end of the cochlea, and they wind up to low frequency cells at the apical end of the
cochlea. When excessive noise bombards these cells, it is the high frequency ones
that receive the brunt of the noise. After a significant period the cells can take no more
so they ‘lie down’ to rest - much like walking over a lawn and trampling down some
grass blades. This is often referred to as a temporary threshold shift. After a period of
rest from the noise, (usually sleep or a weekend break from the noise), the hair cells
will recover - as does lawn grass when no-one is trampling on it and stand up to
discriminate the sounds again. Eventually over time the hair cells will not be able to
recover from repeated noise exposure and a permanent threshold shift will result. This
is much like people repeatedly walking across a strip of lawn and eventually the grass
will die, leaving a brown path through the lawn.
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A condition known as recruitment can sometimes be apparent in noise injury sufferers.
Recruitment results from a reduced dynamic range where the difference between a
sound that is perceived as soft and a sound that is perceived as loud is reduced. This
condition makes it difficult when fitting hearing aids as the loudness of the hearing aid
must be closely monitored. However, knowing of its existence explains why some
hearing impaired people ask you to speak up and when you do, you are accused of
shouting. Loud sounds ‘hurt’, even if they are only slightly louder than threshold
levels. Recruitment is also evident in other forms of sensorineural hearing loss.
Head Trauma
We know that a blow to the head can cause middle ear loss through perforation of the
tympanic membrane and/or dislodgment of the ossicular chain. Further damage in the
inner ear can also occur from head trauma. The inner ear may be harmed in any
number of ways, from being torn or stretched, or from loss of oxygen causing
deterioration to the hair cells. The cochlea itself can become fractured, presenting a
severe to profound hearing loss. The Organ of Corti may be flattened or destroyed
completely. Rupture of the round window is also possible, especially from diving
accidents or acoustic trauma. A fistula can also result from trauma allowing fluid to
leak out from the cochlea. A fistula is an abnormal opening in the oval or round
windows. Any of these conditions will result in a significant sensorineural hearing
loss.
Presbycusis
Presbycusis is also sometimes written as Presbycusis. It is an acquired loss of hearing
associated with the aging process.
It is reasonable to presume that this process actually begins early in life as our ability
to hear ultra high frequencies has deteriorated by the age of 18. However, this does not
explain why some of us lose our hearing through the aging process and some of us
retain relatively good hearing well into our 80’s or 90’s. The process of losing one’s
hearing through age can be equated to the condition of baldness. Some of us lose our
hair, some of us don’t. Those of us that are losing our hair, lose only some of it, others
all of it. Some of us lose our hair quickly, others much more slowly. The same can be
said of losing our hearing.
Presbycusis involves the cochlea but probably also involves a deterioration of the
neural pathways. The resultant hearing loss may vary from mild to profound and again
begins in the high frequencies, but usually does not produce the ‘notch’ characteristic
of noise injury. Hearing loss from presbycusis is usually bilateral, gently sloping high
frequency and of a sensorineural nature.
Recruitment is also common in presbycusis. Poor speech discrimination is often a
feature of presbycusis. That is, even when speech is made loud enough to be heard the
person still has trouble understanding what is said.
Acoustic Schwannoma or Acoustic Neuroma
This generally benign tumour grows on the eighth nerve usually in the internal
auditory meatus at the brain stem. The area known as the cerebellopontine angle
provides a perfect space for this type of tumour to develop from the internal auditory
canal. Tumours are usually unilateral but may be bilateral.
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The larger the acoustic neuroma, the more likely it will cause disruptions to the hearing
and balance. The tumour can also put pressure on the facial nerve as this is also
situated within the internal auditory canal. Symptoms of unilateral or asymmetrical
hearing loss, balance problems (usually falling to one side) and facial palsy are
strongly indicative of an acoustic neuroma. Unilateral tinnitus and a feeling of fullness
or pressure on one side of the head will also be alarming to the clinician if reported.
Speech discrimination is usually worse than would be expected for the degree of
hearing loss.
Surgery is one option for a neuroma. Occasionally, neuromas are monitored to see
whether their removal is necessary or whether removal will cause more problems. Ear,
Nose and Throat Specialists and/or Neurosurgeons make these sorts of decisions.
During surgery the acoustic nerve might be damaged, resulting in partial or complete
hearing loss on that side. If the facial nerve is involved and also has to be severed,
facial palsy will result along with over-lacrimation (ie, excessive production of tears)
of the eyes and alterations in the sense of taste, as these functions are managed by
branches of the facial nerve. However, there is intra-operative monitoring of the facial
nerve that usually means that its function is retained.
Ototoxic medications
Ototoxic literally means poisonous to the ears. There are many medications that can
result in a hearing loss. Most of these will cause a permanent hearing loss but some
hearing loss from ototoxic medication is reversible. Some ototoxic medications will
also cause tinnitus and/or vestibular problems.
Some medications that may cause hearing loss and or tinnitus are:

Aminoglycosides: these are a group of antibiotics that include Gentamycin

Salicylates: aspirin is a salicylate that, when high doses are used, causes a hearing
loss that is reversible

Quinine is an anti-malarial that causes a reversible hearing loss

Anti-cancer medications especially Cisplatin.
You may wonder why a medication would be used if it causes a permanent hearing
loss. The answer is usually that there is no other choice. Hearing will often be
monitored if the person is well enough to be tested.
Large Vestibular Aqueduct Syndrome
LVAS refers to an anomaly of the inner ear. The vestibular aqueduct is attached to the
inner ear at the vestibule and is filled with perilymph. The name of the syndrome is selfexplanatory – the vestibular aqueduct is larger than it should be. The diagnosis of this
syndrome has been made possible with the sophisticated scanning that is now available.
It is not clear exactly how the large vestibular aqueduct causes a hearing loss but it is well
documented that people with LVAS can lose their hearing suddenly from minor trauma, ie
a small bump to the head may cause an immediate and significant loss of hearing. If treated
immediately there can be some recovery. Treatment can involve steroids so an urgent
doctor’s appointment should be encouraged.
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Idiopathic Sudden Hearing Loss
Idiopathic means that the reason for the hearing loss is not exactly known. That is, for
some reason that particular person has a sudden loss of hearing that does not relate to
any external cause and there is nothing obvious causing the loss.
This type of hearing loss can be very difficult for the person because it is not able to be
explained and the effect of the loss is dramatic. If a person came to you describing that
their hearing has dropped suddenly you could do a hearing test but you would
encourage the person to go to their doctor immediately because occasionally doctors
can take steps to stop further deterioration or to help recover some of the hearing.
The effects of pathologies of the inner ear
Pathologies of the inner ear normally cause a permanent hearing problem.
It is unlikely medical treatment will restore the hearing.
Hearing loss caused by pathologies of the inner ear is called sensorineural loss.
The extent of the hearing loss can range from mild to profound.
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PSEUDOHYPOACUSIS
The aim of a hearing test is to establish the softest sound or threshold for each ear at
different frequencies. A very small number of people are unable to do this.
Occasionally, a person will deliberately not respond to the softest sound that they can
hear. There are many terms that are used to describe this.
Pseudohypoacusis is one of the terms we use to describe this. Other terms that are
used include nonorganic hearing loss and malingering.
These terms are usually used to differentiate those people who will not respond to
threshold from those who are not capable of completing a hearing test.
In other words, these terms are used to describe people who could do the hearing test if
they were motivated to do so. Therefore, there is usually some motivation for not
responding to threshold. The motivations for exaggerating hearing levels usually fall
under three broad categories: attention seeking; genuine belief that they cannot hear or
financial gain.
The people who exaggerate a hearing loss may genuinely believe they cannot hear the
sounds being presented so they need very careful handling. There are many tests that
can help you to determine if a person is exaggerating their hearing levels. These tests
and your developing experience with performing hearing tests will help you to
determine the person’s actual hearing thresholds.
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SUMMARY
This learning guide has not done justice to the complex area of pathologies of the ear.
There are many conditions that result in hearing loss that have only been mentioned,
eg, mastoiditis, rubella, CMV, toxoplasmosis. Others have not even been mentioned,
eg, measles, mumps, exostoses, bat ears, Paget’s Disease, syphilis, herpes.
“Sometimes, a client will have two or more pathologies that interact and cause a
different type or degree of hearing loss than what you would expect. Clients often
know more about what is happening to them than you do, so it is always wise to ask
relevant questions when you need information.”
You should consider this as the beginning of your learning about pathologies.
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SUMMARY OF PATHOLOGIES
PATHOLOGY
SYMPTOMS
OTOSCOPIC
INSPECTION
Redness, flaky skin,
swelling
Cannot see the tympanic
membrane
A hole in the tympanic
membrane
Tympanic membrane is
red and perhaps bulging
Otitis Externa
Pain, itchiness
Occluding Wax /
Cerumen
Perforation
Reduced hearing
Otitis Media
Pain, fever, reduced
hearing
Cholesteatoma
Reduced hearing or
there may be no
symptoms.
Otosclerosis
Reduced hearing,
possibly tinnitus
Ossicular
Discontinuity
Reduced hearing
Meniere’s Syndrome
Dull roaring tinnitus,
severe nausea and
vertigo, sensation of
fullness, sudden
hearing loss that
fluctuates, difficulty
with speech
discrimination
Hearing loss following Normal tympanic
illness
membrane and ear canal
Meningitis
Reduced hearing
Trauma
Sudden hearing loss
Noise Injury
Gradual hearing loss
Presbycusis
Gradual hearing loss
Acoustic Schwanoma/
Neuroma
Asymmetrical hearing
loss, unilateral tinnitus
Whitish growth in the
tympanic membrane,
possibly with a smelly
discharge.
Normal tympanic
membrane and ear canal,
sometimes a rosy glow on
the TM.
Malleus may not be
visible behind the
tympanic membrane,
possibly a torn tympanic
membrane
Normal tympanic
membrane and ear canal
Tympanic membrane may
be ruptured
Normal tympanic
membrane and ear canal
Normal tympanic
membrane and ear canal
Normal tympanic
membrane and ear canal
HEARING LOSS
Minimal, temporary
conductive
Minimal, temporary
conductive
Temporary conductive,
may be mild or moderate
Temporary conductive.
The level of hearing loss
depends on the
progression of the disease.
There may or may not be
a hearing loss.
Unilateral or bilateral,
conductive, progressive,
medically treatable
Conductive, moderate
Sudden onset, fluctuating,
sensorineural, affects the
low frequencies to a
greater degree
Unilateral or bilateral,
profound sensorineural
hearing loss
Permanent, sensorineural,
possibly profound loss
Permanent, sensorineural,
possibly a noise notch
Bilateral, high frequency,
gently sloping, of varying
degrees
Asymmetrical hearing
loss, ie a difference in
hearing between the ears.
Sensorineural.
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