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TOPIC
2
CAUSES OF HEARING
IMPAIRMENT
Outer and Middle Ear Disorders

Structural defects due to embryologic
malformations

Structural changes secondary to
infection or trauma
Outer Ear Disorders

Microtia and atresia
Microtia
“an abnormal smallness of the auricle”
Atresia
“the absence of
an opening of
the external
canal”
Outer Ear Disorders

Microtia and atresia

Impacted cerumen

Perforation of the tympanic membrane
Perforation of the TM
n
An example of the audiogram illustrating the flat,
mild, conductive hearing loss that can occur with a
perforated tympanic membrane
Outer Ear Disorders

Microtia and atresia

Impacted cerumen

Perforation of the tympanic membrane

Other
Middle Ear Disorders

Otitis Media



Most common
cause of transient
conductive hearing
loss in children
Inflamation of the
middle ear
Caused by
eustachian tube
failure
Otitis Media
n
Three examples of
the usual
characteristics of a
conductive hearing
loss arising from
otitis media
Ways to Classify Otitis Media
 With or without effusion
 Fluid type
 Serous
 Suppurative
 Mucoid
Ways to Classify Otitis Media
 With or without effusion
 Fluid type
 Duration
 Acute
 Chronic
 Subacute
 Persistent
 Recurrent
Otitis Media Facts

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76-95% of all kids will have one episode of OM by
age 6
Prevalence is highest during the first two years of life
50% of all kids with one episode before their first
birthday will have 6 or more bouts within two years
Most episodes occur in winter and spring
Risk factors

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
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Cleft palate
Down syndrome
Native Americans
Urban poor
Day care
Secondhand smoke
Middle Ear Disorders

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Otitis media
Otosclerosis
Otosclerosis
“a bone disorder that affects the stapes
and the bony labyrinth of the inner ear.
The disease process is characterized by
resorption of bone and new spongy
formation around the stapes and oval
window”
Otosclerosis

Facts:
 Hereditary
 Women are more likely
to develop the disorder
 Usually bilateral
 progressive
Middle Ear Disorders



Otitis media
Otosclerosis
Cholesteatoma
Cholesteatoma
“an epithelial pocket that forms on the
tympanic membrane. Once the pocket
forms, the normal shedding of
epithelium results in growth of the
tumor”
Middle Ear Disorders




Otitis media
Otosclerosis
Cholesteatoma
Other

Physical trauma
Physical Trauma of the Middle
Ear
Here’s an example of
an audiogram
resulting from
disarticulation of the
ossicular chain
Middle Ear Disorders




Otitis media
Otosclerosis
Cholesteatoma
Other



Physical trauma
Barotrauma
Middle ear tumors

Glomus tumor
Cochlear Disorders

Syndromes and inherited disorders


Syndromic disorders
Nonsyndromal disorders
Syndromes and Inherited Disorders Resulting in
Sensorineural Hearing Loss
Types of Nonsyndromic
Disorders




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Dominant
Dominant progressive
Dominant progressive with adult onset
Recessive hereditary SNHL
X-linked
Cochlear Disorders


Syndromes and inherited disorders
Noise induced hearing loss
Noise Induced Hearing Loss
The degree of SNHL depends on
 The intensity of the noise
 The spectral composition of the noise
 The duration of exposure
 Individual susceptibility
OSHA Damage Risk Criteria
Noise Induced SNHL

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
Noise notch
Cummulative
Progressive
Cochlear Disorders

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Syndromes and inherited disorders
Noise induced hearing loss
Other trauma
Infections
Infections

Congenital

Cytomegalovirus

HIV

Rubella

Syphilis

Toxoplasmosis
Infections

Acquired

Herpes Zooster Oticus (Chicken Pox)

Mumps

Syphilis
Cochlear Disorders

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Syndromes and inherited disorders
Noise induced hearing loss
Other trauma
Infections
Ototoxicity
Ototoxicity
 Some antibiotics that are often ototoxic:

Amikacin

Dihydrostreptomycin

Garamycin

Gentamicin
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Kanamycin
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Neomycin

Netilmicin
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Streptomycin
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Tobramycin
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Viomycin
Ototoxicity

Chemotherapy
 Carboplatin
 Cisplatin

Drugs that cause reversible hearing loss
 Quinine
 Salicylates (aspirin)
 Loop diuretics

Drugs that may be harmful during pregnancy
 Accutane
 Dilantin
 Quinine
 Thalidomide
Cochlear Disorders
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Syndromes and inherited disorders
Noise induced hearing loss
Other trauma
Infections
Ototoxicity
Meniere’s Disease
Meniere’s Disease

Symptoms

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Tinnitus
Vertigo
Unilateral
sensorineural
hearing loss
Cochlear Disorders
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Syndromes and inherited disorders
Noise induced hearing loss
Other trauma
Infections
Ototoxicity
Meniere’s Disease
Presbycusis
Presbycusis
Central Auditory Disorders

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VIII Nerve tumors
Other diseases of the VIII Nerve
Neural disorders

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Brain Stem disorders
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Cochlear neuritis
Diabetes mellitus
Infarcts
Gliomas
Multiple sclerosis
Temporal Lobe disorders