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Seminar

DEAFNESSSubmitted to : Ms. Sucheta Yangad

Professor (Medical-Surgical Nursing)

Submitted by : Mr. Swapnil A Mahapure

M.Sc. Nursing 1st

year

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Definition of deafnessAccording to IDEA (INTERNATIONAL DEAF EDUCATION ASSOCIATION)

Deafness is defined as a hearing impairment that is so severe that the child is

impaired in processing linguistic information through hearing, with or without

amplification.

Anatomy of the EarThe ear is divided into three main regions: (1) the external ear, which collects sound waves and channels

them inward; (2) the middle ear, which conveys sound vibrations to the oval window; and (3) the internal

ear, which houses the receptors for hearing and equilibrium.

External (Outer) Ear

The external (outer) ear consists of the auricle, external auditory canal, and eardrum. The auricle

(pinna) is a flap of elastic cartilage shaped like the flared end of a trumpet and covered by skin. The rim

of the auricle is the helix; the inferior portion is the lobule. Ligaments and muscles attach the auricle tothe head. The external auditory canal (audit- _hearing) is a curved tube about 2.5 cm (1 in.) long that

lies in

the temporal bone and leads to the eardrum. The tympanic membrane (tim-PAN-ik; tympan- _ a drum)

or eardrum is a thin, semitransparent partition between the external auditory canal and middle ear. The

tympanic membrane is covered by epidermis and lined by simple cuboidal epithelium. Between the

epithelial layers is connective tissue composed of collagen, elastic fibers, and fibroblasts. Tearing of the

tympanic membrane is called a perforated eardrum. It may be due to pressure from a cotton swab,

trauma, or a middle ear infection, and usually heals within a month. The tympanic membrane may be

examined directly by an otoscope (oto- _ ear; -skopeo _ to view), a viewing instrument that illuminates

and magnifies the external auditory canal and tympanic membrane. Near the exterior opening, the

external auditory canal contains a few hairs and specialized sweat glands called ceruminous glands (se-

ROO-mi-nus) that secrete earwax or cerumen. The combination of hairs and cerumen helps prevent dust

and foreign objects from entering the ear. Cerumen

also prevents damage to the delicate skin of the external ear canal by water and insects. Cerumen usually

dries up and falls out of the ear canal. However, some people produce a large amount of cerumen, which

can become impacted and can muffle incoming sounds. The treatment for impacted cerumen is usually

periodic ear irrigation or removal of wax with a blunt instrument by trained medical personnel.

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Middle EarThe middle ear is a small, air-filled cavity in the petrous portion of the temporal bone that is lined by

epithelium. It is separated from the external ear by the tympanic membrane and from the internal ear by a

thin bony partition that contains two small membrane-covered openings: the oval window and the round

window. Extending across the middle ear and attached to it by ligaments are the three smallest bones inthe body, the auditory ossicles, which are connected by synovial joints. The bones, named for their

shapes, are the malleus, incus, and stapescommonly called the hammer, anvil, and stirrup, respectively.

The handle of the malleus (MAL-e -us) attaches to the internal surface of the tympanic membrane. The

head of the malleus articulates with the body of the incus. The incus (ING-kus), the middle bone in the

series, articulates with the head of the stapes. The base or footplate of the stapes (STA -pez) fits into

the oval window. Directly below the oval window is another opening, the round window, which is

enclosed by a membrane called the secondary tympanic membrane. Besides the ligaments, two tiny

skeletal muscles also attach to the ossicles. The tensor tympani muscle, which is supplied by the

mandibular branch of the trigeminal (V) nerve, limits movement and increases tension on the eardrum to

prevent damage to the inner ear from loud noises.

The stapedius muscle, which is supplied by the facial (VII) nerve, is the smallest skeletal muscle in the

human body. By dampening large vibrations of the stapes due to loud noises, it protects the oval window,

but it also decreases the sensitivity of hearing. For this reason, paralysis of the stapedius muscle is

associated with hyperacusia (abnormally sensitive hearing). Because it takes a fraction of a second for

the tensor tympani and stapedius muscles to contract, they can protect the inner ear from prolonged loud

noises, but not from brief ones such as a gunshot. The anterior wall of the middle ear contains an opening

that leads directly into the auditory (pharyngotympanic) tube, commonly known as the eustachian

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tube. The auditory tube, which consists of both bone and elastic cartilage, connects the middle ear with

the nasopharynx (superior portion of the throat). It is normally closed at its medial (pharyngeal) end.

During swallowing and yawning, it opens, allowing air to enter or leave the middle ear until the pressure

in the middle ear equals the atmospheric pressure. Most of us have experienced our ears popping as the

pressures equalize. When the pressures are balanced, the tympanic membrane vibrates freely as sound

waves strike it. If the pressure is not equalized, intense pain, hearing impairment, ringing in the ears, andvertigo could develop.

The auditory tube also is a route for pathogens to travel from the nose and throat to the middle ear,

causing the most common type of ear infection.

Internal (Inner) Ear

The internal (inner) ear is also called the labyrinth (LAB-irinth) because of its complicated series of

canals. Structurally, it consists of two main divisions: an outer bony labyrinth that encloses an inner

membranous labyrinth. The bony labyrinth is a series of cavities in the petrous portion of the temporal

bone divided into three areas: (1) the semicircular canals and (2) the vestibule, both of which contain

receptors for equilibrium, and (3) the cochlea, which contains receptors for hearing. The bony labyrinth is

lined with periosteum and contains perilymph. This fluid, which is chemically similar to cerebrospinal

fluid, surrounds the membranous labyrinth, a series of epithelial sacs and tubes inside the bony

labyrinth that have the same general form as the bony labyrinth. The epithelial membranous labyrinth

contains endolymph. The level of potassium ions (K_) in endolymph is unusually high for an

extracellular fluid, and potassium ions play a role in the generation of auditory signals (described shortly).

The vestibule (VES-ti-bu l) is the oval central portion of the bony labyrinth. The membranous labyrinth

in the vestibule consists of two sacs called the utricle (U -tri-kl _ little bag) and the saccule (SAK-u l _

little sac), which are connected by a small duct. Projecting superiorly and posteriorly from the vestibule

are the three bony semicircular canals, each of which lies at approximately right angles to the other two.

Based on their positions, they are named the anterior, posterior, and lateral semicircular canals. The

anterior and posterior semicircular canals are vertically oriented; the lateral one is horizontally oriented.At one end of each canal is a swollen enlargement called the ampulla (am-PUL-la _ saclike duct). The

portions of the membranous labyrinth that lie inside the bony semicircular canals are called the

semicircular ducts. These structures connect with the utricle of the vestibule.

The vestibular branch of the vestibulocochlear (VIII) nerve consists ofampullary, utricular, and saccular

nerves. These nerves contain both first-order sensory neurons and motor neurons that synapse with

receptors for equilibrium. The firstorder sensory neurons carry sensory information from the receptors,

and the motor neurons carry feedback signals to the receptors, apparently to modify their sensitivity. Cell

bodies of the sensory neurons are located in the vestibular ganglia. Anterior to the vestibule is the

cochlea, a bony spiral canal that resembles a snails shell and makes almost three turns around a central

bony core called the modiolus. Sections through the cochlea reveal that it is divided into three channels:

cochlear duct, scala vestibuli, and scala tympani . The cochlear duct (scala media) is a continuation of

the membranous labyrinth into the cochlea; it is filled with endolymph. The channel above the cochlear

duct is the scala vestibuli, which ends at the oval window. The channel below is the scala tympani,

which ends at the round window. Both the scala vestibuli and scala tympani are part of the bony labyrinth

of the cochlea; therefore, these chambers are filled with perilymph. The scala vestibuli and scala tympani

are completely separated by the cochlear duct, except for an opening at the apex of the cochlea, the

helicotrema. The cochlea adjoins the wall of the vestibule, into which the scala vestibuli opens. The

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perilymph in the vestibule is continuous with that of the scala vestibuli. The vestibular membrane

separates the cochlear duct from the scala vestibuli, and the basilar membrane separates the cochlear

duct from the scala tympani. Resting on the basilar membrane is the spiral organ or organ of Corti. The

spiral organ is a coiled sheet of epithelial cells, including supporting cells and about 16,000 hair cells,

which are the receptors for hearing. There are two groups of hair cells: The inner hair cells are arranged

in a single row whereas the outer hair cells are arranged in three rows. At the apical tip of each hair cellare 4080 stereocilia that extend into the endolymph of the cochlear duct. Despite their name, stereocilia

are actually long, hairlike microvilli arranged in several rows of graded height. At their basal ends, inner

and outer hair cells synapse both with first-order sensory neurons and with motor neurons from the

cochlear branch of the vestibulocochlear (VIII) nerve. Cell bodies of the sensory neurons are located in

the spiral ganglion. Although outer hair cells outnumber them by 3 to 1, the inner hair cells synapse with

9095% of the first-order sensory neurons in the cochlear nerve that relay auditory information to the

brain. By contrast, 90% of the motor neurons in the cochlear nerve synapse with outer hair cells. The

tectorial membrane (tector- _ covering), a flexible gelatinous membrane, covers the hair cells of the

spiral organ. In fact, the ends of the stereocilia of the hair cells are embedded in the tectorial membrane

while the bodies of the hair cells rest on the basilar membrane.

Overview of Hearing

To understand hearing loss it is important to understand how normal hearing takes place. There are 2

different pathways by which sound waves produce thesensationof hearing: air conduction and bone

conduction.

In air conduction, sound waves move through the air in the external auditory canal (the "earcanal"

between the outside air and youreardrum). The sound waves hit thetympanic membrane(eardrum) and

cause thetympanicmembraneto move.

The bones in themiddle earare connected to the tympanic membrane. When the tympanic membrane

moves, this movement is transmitted to the bones. These 3 bones are called themalleus, theincus, and

thestapes. Movement of the stapes causes pressure waves in the fluid-filledinner ear.

Thecochleais an inner ear structure surrounded by fluid. It contains multiple small hairs. Pressure

waves in the fluid cause the hairs to move. This movement stimulates the auditorynerve. Different

frequencies of noises stimulate different hairs on the cochlea, which translate to the sensation of sounds

of different pitch.

Hearing by bone conduction occurs when a sound wave or other source of vibration causes the bones oftheskullto vibrate. These vibrations are transmitted to the fluid surrounding the cochlea and hearing

results.

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Physiology of HearingThe following events are involved in hearing :

1. The auricle directs sound waves into the external auditory canal.

2. When sound waves strike the tympanic membrane, the alternating high- and low-pressure of the

air causes the tympanic membrane to vibrate back and forth. The distance it moves, which is very

small, depends on the intensity and frequency of the sound waves. The eardrum vibrates slowly in

response to low-frequency (low-pitched) sounds and rapidly in response to high-frequency (high-

pitched) sounds.

3. The central area of the eardrum connects to the malleus, which also starts to vibrate. The

vibration is transmitted from the malleus to the incus and then to the stapes.

4. As the stapes moves back and forth, it pushes the membrane of the oval window in and out. The

oval window vibrates about 20 times more vigorously than the eardrum because the ossicles

efficiently transmit small vibrations spread over a large surface area (eardrum) into larger

vibrations of a smaller surface (oval window).

5. The movement of the oval window sets up fluid pressure waves in the perilymph of the cochlea.

As the oval window bulges inward, it pushes on the perilymph of the scala vestibuli.6. Pressure waves are transmitted from the scala vestibuli to the scala tympani and eventually to the

round window, causing it to bulge outward into the middle ear.

7. As the pressure waves deform the walls of the scala vestibuli and scala tympani, they also push

the vestibular membrane back and forth, creating pressure waves in the endolymph inside the

cochlear duct.

8. The pressure waves in the endolymph cause the basilar membrane to vibrate, which moves the

hair cells of the spiral organ against the tectorial membrane. This leads to bending of the hair cell

stereocilia, which produces receptor potentials that ultimately lead to the generation of nerve

impulses.

CLASSIFICATION

There are two different types of hearing impairments, conductive hearing impairment and sensorineural

hearing impairment. A third type is a combination of the two called mixed hearing loss. Hearing

impairments are categorized by their type - conductive, sensorineural or both, by their severity, and by the

age of onset. Furthermore, a hearing impairment may exist in only one ear (unilateral) or in both ears

(bilateral).

Conductive hearing loss

A conductive hearing impairment is present when the sound is not reaching the inner ear, the cochlea.This can be due to external ear canal malformation, dysfunction of the eardrum or malfunction of the

bones of the middle ear. The ear drum may show defects from small to total resulting in hearing loss of

different degree. Scar tissue after ear infections may also make the ear drum dysfunction as well as when

it is retracted and adherent to the medial part of the middle ear.

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Dysfunction of the three small bones of the middle ear; hammer, anvil and stapes may result in

conductive hearing loss. The mobility of the ossicles may be impaired of different reasons and disruption

of the ossicular chain due to trauma, infection or anchylosis may also result in hearing loss.

A more common reason is in patients with chronic ear infections that drain continuously or start to drain

when the ear canal is obstructed with an air conduction hearing aid mould.

In these patients a direct bone conduction hearing device could be an excellent solution. An implant made

out of titanium is placed in the bone behind the external ear and allowed to osseointegrate and an

impedance-matched hearing aid can be attached. At present there are two such hearing aids on the market;

the Baha 3 by Cochlear BAS and the Ponto by Oticon Medical.

Sensorineural hearing loss

A sensorineural hearing loss is one resulting from dysfunction of the inner ear, the cochlea, the nerve that

transmits the impulses from the cochlea to the hearing centre in the brain or damage in the brain. The

most common reason for sensorineural hearing impairment is damage to the hair cells in the cochlea. As

we grow older the hair cells degenerate and lose their function, and our hearing deteriorates. Depending

on the definition it could be estimated that more than 50% of the population over the age of 70 has animpaired hearing. Impaired hearing is the most common physical handicap in the industrialized world.

Another common reason for hearing loss due to hair cell damage is noise-induced hearing loss. These

types of hearing loss are often most pronounced in the high frequency range. This will often interfere with

speech understanding, as it is in the high frequency range that we find the consonant sounds that are most

important especially in noisy surroundings. Head trauma, ear infections, tumours and ototoxic drugs such

as gentamycine are other reasons for sensorineural hearing loss.

Hair cells that are damaged cannot be replaced with any surgical procedure, even if research with stem

cell treatment is presently going on in many institutions. The clinical application of this will however not

yet be available for many years. Protection from noise exposure is at present the only way to reduce the

hair cell damage. Conventional air conduction hearing aids are often prescribed for patients with

sensorineural hearing loss. The outcome with modern types of hearing aids is often excellent, but speech

understanding could still be a problem in demanding situations.

Total or near total sensorineural deafness could be the result of congenital malformations, head trauma or

inner ear infection. In patients with total or near total deafness, an air conduction aid could not be used

even if the drum and middle ear are normal.

Mixed hearing loss

Mixed hearing loss is a combination of the two types discussed above. Chronic ear infection that is a

fairly common diagnosis could result in a defect ear drum and/or middle ear ossicle damages. Surgery is

often attempted but not always successful. On top of the conductive loss a sensory component is oftenadded. If the ear is dry and not infected an air conduction aid could be tried, but if the ear is draining a

direct bone condition hearing aid is often the best solution. If the conductive part of the hearing loss is

more than 3035dBan air conduction device could have problems overcoming this gap. A direct bone

conduction aid like the Baha or the Ponto could in this situation be a good option.

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Age of onset

The age at which hearing loss occurs is crucial for the acquisition of a spoken language.

1. Prelingual deafness

Prelingual deafness is hearing impairment that is sustained prior to the acquisition of

language, which can occur as a result of a congenital condition or through hearing loss in earlyinfancy. Prelingual deafness impairs an individual's ability to acquire a spoken language.

Children born into signing families rarely have delays in language development, but most

prelingual hearing impairment is acquired via either disease or trauma rather than genetically

inherited, so families with deaf children nearly always lack previous experience with sign

language.

2. Post-lingual deafness

Post-lingual deafness is hearing impairment that is sustained after the acquisition of

language, which can occur as a result ofdisease, trauma, or as a side-effect of a medicine.

Typically, hearing loss is gradual and often detected by family and friends of affected individuals

long before the patients themselves will acknowledge the disability. Post-lingual deafness is farmore common than pre-lingual deafness.

Unilateral and bilateral hearing impairment

Patients with Unilateral Hearing Loss or Single-Sided Deafness (SSD) have difficulty in:

hearing conversation on their impaired side

localizing sound

understanding speech in the presence of background noise.

In quiet conditions, speech discrimination is approximately the same for normal hearing and those with

unilateral deafness; however, in noisy environments speech discrimination varies individually and ranges

from mild to severe.

A similar effect can result from King-Kopetzky syndrome (also known as Auditory disability with normal

hearing and obscure auditory dysfunction), which is characterized by an inability to process out

background noise in noisy environments despite normal performance on traditional hearing tests.

One reason for the hearing problems these patients often experience is due to the head shadow effect.

Newborn children with no hearing on one side but one normal ear could still have problems. Speech

development could be delayed and difficulties to concentrate in school are common. More children with

unilateral hearing loss have to repeat classes than their peers. Taking part in social activities could be aproblem. Early aiding is therefore of utmost importance.

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Quantification of hearing loss

The severity of a hearing impairment is ranked according to the additional intensity above a nominal

threshold that a sound must be before being detected by an individual; it is (measured in DECIBELS of

hearing loss, or dB HL). Hearing impairment may be ranked as mild, moderate, moderately severe, severe

or profound as defined below:

Mild:

for adults: between 26 and 40 dB HL

for children: between 20 and 40 dB HL

Moderate: between 41 and 55 dB HL

Moderately severe: between 56 and 70 dB HL

Severe: between 71 and 90 dB HL

Profound: 91 dB HL or greater

Hearing sensitivity varies according to the frequency of sounds. To take this into account, hearing

sensitivity can be measured for a range of frequencies and plotted on anaudiogram.

For certain legal purposes such as insurance claims, hearing impairments are described in terms of

percentages. Given that hearing impairments can vary by frequency and that audiograms are plotted with

a logarithmic scale, the idea of a percentage of hearing loss is somewhat arbitrary, but where decibels of

loss are converted via a recognized legal formula, it is possible to calculate a standardized "percentage of

hearing loss" which is suitable for legal purposes only.

Another method for quantifying hearing impairments is a speech-in-noise test. As the name implies, a

speech-in-noise test gives an indication of how well one can understand speech in a noisy environment. A

person with a hearing loss will often be less able to understand speech, especially in noisy conditions.

This is especially true for people who have a sensorineural losswhich is by far the most common type

of hearing loss. As such, speech-in-noise tests can provide valuable information about a person.

CAUSES

The following are some of the major causes of hearing loss.

1. Age

Presbycusis, the progressive loss of ability to hear high frequencies with increasing age,

begins in early adulthood, but does not usually interfere with ability to understand conversation

until much later. Although genetically variable it is a normal concomitant of aging and is distinct

from hearing losses caused by noise exposure, toxins or disease agents.

2. Long-term exposure to environmental noise

Populations of people living near airports or freeways are exposed to levels of noise

typically in the 65 to 75 dB(A) range. If lifestyles include significant outdoor or open window

conditions, these exposures over time can degrade hearing. TheU.S. EPAand various states have

set noise standards to protect people from these adverse health risks. The EPA has identified the

level of 70 dB(A) for 24 hour exposure as the level necessary to protect the public from hearing

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loss and other disruptive effects from noise, such as sleep disturbance, stress-related problems,

learning detriment, etc. (EPA, 1974).

3. Noise-induced hearing loss(NIHL) typically is centered at 3000, 4000, or 6000 Hz. As noise

damage progresses, damage starts affecting lower and higher frequencies. On an audiogram, the

resulting configuration has a distinctive notch, sometimes referred to as a "noise notch." As aging

and other effects contribute to higher frequency loss (68 kHz on an audiogram), this notch may

be obscured and entirely disappear. Louder sounds cause damage in a shorter period of time.

Estimation of a "safe" duration of exposure is possible using an exchange rate of 3 dB. As 3 dB

represents a doubling of intensity of sound, duration of exposure must be cut in half to maintain

the same energy dose. For example, the "safe" daily exposure amount at 85 dB A, known as

an exposure action value, is 8 hours, while the "safe" exposure at 91 dB(A) is only 2 hours

(National Institute for Occupational Safety and Health, 1998). Note that for some people, sound

may be damaging at even lower levels than 85 dB A. Exposures to other ototoxins (such as

pesticides, some medications including chemotherapy, solvents, etc.) can lead to greater

susceptibility to noise damage, as well as causing their own damage. This is called

a synergistic interaction.

Many people are unaware of the presence of environmental sound at damaging levels, or

of the level at which sound becomes harmful. Common sources of damaging noise levels include

car stereos, children's toys, transportation, crowds, lawn and maintenance equipment, power

tools, gun use, and even hair dryers. Noise damage is cumulative; all sources of damage must be

considered to assess risk. If one is exposed to loud sound (including music) at high levels or for

extended durations (85 dB A or greater), then hearing impairment will occur. Sound levels

increase with proximity; as the source is brought closer to the ear, the sound level increases.

4. Genetic

Hearing loss can be inherited. Both dominant genes and recessive genes exist which can

cause mild to profound impairment. If a family has a dominant gene for deafness it will persist

across generations because it will manifest itself in the offspring even if it is inherited from only

one parent. If a family had genetic hearing impairment caused by a recessive gene it will not

always be apparent as it will have to be passed onto offspring from both parents. Dominant and

recessive hearing impairment can be syndromic ornonsyndromic. Recent gene mapping has

identified dozens of nonsyndromic dominant (DFNA#) and recessive (DFNB#) forms of

deafness.

a. The first gene mapped for non-syndromic deafness, DFNA1, involves a splice site

mutation in the formin related homolog diaphanous 1 (DIAPH1). A single base change in

a large Costa Rican family was identified as causative in a rare form of low frequency

onset progressive hearing loss with autosomal dominant inheritance exhibiting variable

age of onset and complete penetrance by age 30.

b. The most common type of congenital hearing impairment in developed countries is

DFNB1, also known as Connexin 26 deafness orGJB2-related deafness.

c. The most common dominant syndromic forms of hearing impairment includeStickler

syndromeandWaardenburg syndrome.

http://en.wikipedia.org/wiki/Noise-induced_hearing_losshttp://en.wikipedia.org/wiki/Noise-induced_hearing_losshttp://en.wikipedia.org/wiki/Exposure_action_valuehttp://en.wikipedia.org/wiki/Nonsyndromic_deafnesshttp://en.wikipedia.org/wiki/Nonsyndromic_deafnesshttp://en.wikipedia.org/wiki/Nonsyndromic_deafnesshttp://en.wikipedia.org/wiki/GJB2http://en.wikipedia.org/wiki/GJB2http://en.wikipedia.org/wiki/GJB2http://en.wikipedia.org/wiki/Stickler_syndromehttp://en.wikipedia.org/wiki/Stickler_syndromehttp://en.wikipedia.org/wiki/Stickler_syndromehttp://en.wikipedia.org/wiki/Stickler_syndromehttp://en.wikipedia.org/wiki/Waardenburg_syndromehttp://en.wikipedia.org/wiki/Waardenburg_syndromehttp://en.wikipedia.org/wiki/Waardenburg_syndromehttp://en.wikipedia.org/wiki/Waardenburg_syndromehttp://en.wikipedia.org/wiki/Stickler_syndromehttp://en.wikipedia.org/wiki/Stickler_syndromehttp://en.wikipedia.org/wiki/GJB2http://en.wikipedia.org/wiki/Nonsyndromic_deafnesshttp://en.wikipedia.org/wiki/Exposure_action_valuehttp://en.wikipedia.org/wiki/Noise-induced_hearing_loss

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d. The most common recessive syndromic forms of hearing impairment arePendred

syndrome, Large vestibular aqueduct syndrome andUsher syndrome.

e. The congenital defectmicrotiacan cause full or partial deafness depending upon the

severity of the deformity and whether or not certain parts of the inner or middle ear are

affected.

f. Mutations Cause of Autosomal-Recessive Nonsyndromic Hearing Impairment.

5. Disease or illness

a. Measlesmay result inauditory nervedamage

b. Meningitismay damage the auditory nerve or the cochlea

c. Autoimmune diseasehas only recently been recognized as a potential cause for cochlear

damage. Although probably rare, it is possible for autoimmune processes to target the

cochlea specifically, without symptoms affecting other organs.Wegener's

granulomatosisis one of the autoimmune conditions that may precipitate hearing loss.

d. Mumps(Epidemic parotitis) may result in profound sensorineural hearing loss (90 dB ormore), unilateral (one ear) or bilateral (both ears).

e. Presbycusisis a progressive hearing impairment accompanying age, typically affecting

sensitivity to higher frequencies (above about 2 kHz).

f. Adenoids that do not disappear by adolescence may continue to grow and may obstruct

the Eustachian tube, causing conductive hearing impairment and nasal infections that can

spread to the middle ear.

g. AIDSandARCpatients frequently experience auditory system anomalies.

h. HIV(and subsequent opportunistic infections) may directly affect the cochlea and central

auditory system.

i. Chlamydiamay cause hearing loss in newborns to whom the disease has been passed atbirth.

j. Fetal alcohol syndromeis reported to cause hearing loss in up to 64% of infants born

toalcoholicmothers, from the ototoxic effect on the developing fetus plus malnutrition

during pregnancy from the excessalcoholintake.

k. Premature birthresults in sensorineural hearing loss approximately 5% of the time.

l. Syphilisis commonly transmitted from pregnant women to their fetuses, and about a third

of the infected children will eventually become deaf.

m. Otosclerosisis a hardening of the stapes (or stirrup) in the middle ear and causes

conductive hearing loss.

n. Medulloblastomaand other types ofBrain Tumorscan result in hearing loss, whether by

the placement of the tumor around theVestibulocochlear nerve, surgical resection, orplatinum-basedchemotherapydrugs such ascisplatin.

o. Superior canal dehiscence, a gap in the bone cover above the inner ear, can lead to low-

frequency conductive hearing loss, autophony and vertigo.

p. Mnires Disease

Mnires disease is a balance disorder. Its cause is unknown. With the disease, there is a dilation

of the membranous labyrinth resulting from a disturbance in the fluid physiology of the

endolymphatic system. The exact etiology is unknown but is thought to stem from hypersecretion,

http://en.wikipedia.org/wiki/Pendred_syndromehttp://en.wikipedia.org/wiki/Pendred_syndromehttp://en.wikipedia.org/wiki/Pendred_syndromehttp://en.wikipedia.org/wiki/Pendred_syndromehttp://en.wikipedia.org/wiki/Usher_syndromehttp://en.wikipedia.org/wiki/Usher_syndromehttp://en.wikipedia.org/wiki/Usher_syndromehttp://en.wikipedia.org/wiki/Microtiahttp://en.wikipedia.org/wiki/Microtiahttp://en.wikipedia.org/wiki/Microtiahttp://en.wikipedia.org/wiki/Measleshttp://en.wikipedia.org/wiki/Measleshttp://en.wikipedia.org/wiki/Vestibulocochlear_nervehttp://en.wikipedia.org/wiki/Vestibulocochlear_nervehttp://en.wikipedia.org/wiki/Vestibulocochlear_nervehttp://en.wikipedia.org/wiki/Meningitishttp://en.wikipedia.org/wiki/Meningitishttp://en.wikipedia.org/wiki/Autoimmune_diseasehttp://en.wikipedia.org/wiki/Autoimmune_diseasehttp://en.wikipedia.org/wiki/Wegener%27s_granulomatosishttp://en.wikipedia.org/wiki/Wegener%27s_granulomatosishttp://en.wikipedia.org/wiki/Wegener%27s_granulomatosishttp://en.wikipedia.org/wiki/Wegener%27s_granulomatosishttp://en.wikipedia.org/wiki/Mumpshttp://en.wikipedia.org/wiki/Mumpshttp://en.wikipedia.org/wiki/Presbycusishttp://en.wikipedia.org/wiki/Presbycusishttp://en.wikipedia.org/wiki/AIDShttp://en.wikipedia.org/wiki/AIDShttp://en.wikipedia.org/wiki/AIDS-related_complexhttp://en.wikipedia.org/wiki/AIDS-related_complexhttp://en.wikipedia.org/wiki/AIDS-related_complexhttp://en.wikipedia.org/wiki/HIVhttp://en.wikipedia.org/wiki/HIVhttp://en.wikipedia.org/wiki/Chlamydia_infectionhttp://en.wikipedia.org/wiki/Chlamydia_infectionhttp://en.wikipedia.org/wiki/Fetal_alcohol_syndromehttp://en.wikipedia.org/wiki/Fetal_alcohol_syndromehttp://en.wikipedia.org/wiki/Alcoholismhttp://en.wikipedia.org/wiki/Alcoholismhttp://en.wikipedia.org/wiki/Alcoholismhttp://en.wikipedia.org/wiki/Ethanolhttp://en.wikipedia.org/wiki/Ethanolhttp://en.wikipedia.org/wiki/Ethanolhttp://en.wikipedia.org/wiki/Premature_birthhttp://en.wikipedia.org/wiki/Premature_birthhttp://en.wikipedia.org/wiki/Syphilishttp://en.wikipedia.org/wiki/Syphilishttp://en.wikipedia.org/wiki/Otosclerosishttp://en.wikipedia.org/wiki/Otosclerosishttp://en.wikipedia.org/wiki/Medulloblastomahttp://en.wikipedia.org/wiki/Medulloblastomahttp://en.wikipedia.org/wiki/Brain_Tumorshttp://en.wikipedia.org/wiki/Brain_Tumorshttp://en.wikipedia.org/wiki/Brain_Tumorshttp://en.wikipedia.org/wiki/Vestibulocochlear_nervehttp://en.wikipedia.org/wiki/Vestibulocochlear_nervehttp://en.wikipedia.org/wiki/Vestibulocochlear_nervehttp://en.wikipedia.org/wiki/Chemotherapyhttp://en.wikipedia.org/wiki/Chemotherapyhttp://en.wikipedia.org/wiki/Chemotherapyhttp://en.wikipedia.org/wiki/Cisplatinhttp://en.wikipedia.org/wiki/Cisplatinhttp://en.wikipedia.org/wiki/Cisplatinhttp://en.wikipedia.org/wiki/Cisplatinhttp://en.wikipedia.org/wiki/Chemotherapyhttp://en.wikipedia.org/wiki/Vestibulocochlear_nervehttp://en.wikipedia.org/wiki/Brain_Tumorshttp://en.wikipedia.org/wiki/Medulloblastomahttp://en.wikipedia.org/wiki/Otosclerosishttp://en.wikipedia.org/wiki/Syphilishttp://en.wikipedia.org/wiki/Premature_birthhttp://en.wikipedia.org/wiki/Ethanolhttp://en.wikipedia.org/wiki/Alcoholismhttp://en.wikipedia.org/wiki/Fetal_alcohol_syndromehttp://en.wikipedia.org/wiki/Chlamydia_infectionhttp://en.wikipedia.org/wiki/HIVhttp://en.wikipedia.org/wiki/AIDS-related_complexhttp://en.wikipedia.org/wiki/AIDShttp://en.wikipedia.org/wiki/Presbycusishttp://en.wikipedia.org/wiki/Mumpshttp://en.wikipedia.org/wiki/Wegener%27s_granulomatosishttp://en.wikipedia.org/wiki/Wegener%27s_granulomatosishttp://en.wikipedia.org/wiki/Autoimmune_diseasehttp://en.wikipedia.org/wiki/Meningitishttp://en.wikipedia.org/wiki/Vestibulocochlear_nervehttp://en.wikipedia.org/wiki/Measleshttp://en.wikipedia.org/wiki/Microtiahttp://en.wikipedia.org/wiki/Usher_syndromehttp://en.wikipedia.org/wiki/Pendred_syndromehttp://en.wikipedia.org/wiki/Pendred_syndrome

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hypoabsorption, deficit membrane permeability, allergy, viral infection, hormonal imbalance, or

mental stress. The disease usually develops between 40 and 60 years of age.

6. Neurological disorders

Neurological disorders such asmultiple sclerosisand strokes can have an effect on

hearing as well. Multiple sclerosis, or MS, is anautoimmune diseasewhere the immune system

attacks themyelin sheath, a covering that protects the nerves. Once the myelin sheaths are

destroyed there is no possible way at present to repair them. Without the myelin to protect the

nerves, nerves become damaged, creating disorientation for the patient. This is a painful process

and may end in the debilitation of the infected person until they are paralyzed and have one or

more senses gone. One of those may be hearing. If the auditory nerve becomes damaged then the

infected person will become completely deaf in one or both ears. There is no cure for MS.

Astrokeoccurs if there is a clot in the brain, and blood is unable to get to a section of the brain.

Within minutes the oxygen-deprived cells begin to die, causing serious damage to the human

body. Depending on what nerves are damaged, one of the side effects can be deafness.[9]

7. Medications

Some medications cause irreversible damage to the ear, and are limited in their use for

this reason. The most important group is theaminoglycosides(main membergentamicin) and

platinum based chemotherapeutics such ascisplatin.

Some medications may reversibly affect hearing. This includes

some diuretics, aspirin and NSAIDs, andmacrolide antibiotics. Others may cause permanent

hearing loss.

Extremely heavyhydrocodone(Vicodin or Lorcet) abuse is known to cause hearing

impairment. Commentators have speculated that radio talk show hostRush Limbaugh's hearing

loss was at least in part caused by his admitted addiction to narcotic pain killers, in particularVicodin andOxyContin.

8. Exposure to Ototoxic chemicals

In addition to medications, hearing loss can also result from specific drugs; metals, such

aslead;solvents, such astoluene(found incrude oil,gasoline[12]

andautomobile exhaust,[12]

for

example); andasphyxiants.[13]

Combined with noise, theseototoxicchemicals have an additive

effect on a personshearing loss.[13]Hearing loss due to chemicals starts in the high frequency

range and is irreversible. It damages thecochleawith lesions and degrades central portions of

theauditory system.[13]

For some ototoxic chemical exposures, particularly styrene,[14]

the risk of

hearing loss can be higher than being exposed tonoisealone. Controlling noise and usinghearing

protectorsare insufficient for preventing hearing loss from these chemicals. However, taking

antioxidants helps prevent ototoxic hearing loss, at least to a degree.[14]

The following list

provides an accurate catalogue of ototoxic chemicals:

Drugs

antimalarial, antibiotics, anti-inflammatory (non-steroidal), antineoplastic, diuretics

http://en.wikipedia.org/wiki/Multiple_sclerosishttp://en.wikipedia.org/wiki/Multiple_sclerosishttp://en.wikipedia.org/wiki/Multiple_sclerosishttp://en.wikipedia.org/wiki/Autoimmune_diseasehttp://en.wikipedia.org/wiki/Autoimmune_diseasehttp://en.wikipedia.org/wiki/Autoimmune_diseasehttp://en.wikipedia.org/wiki/Myelin_sheathhttp://en.wikipedia.org/wiki/Myelin_sheathhttp://en.wikipedia.org/wiki/Myelin_sheathhttp://en.wikipedia.org/wiki/Strokehttp://en.wikipedia.org/wiki/Strokehttp://en.wikipedia.org/wiki/Strokehttp://en.wikipedia.org/wiki/Deafness#cite_note-stroke-mayoclinic-8http://en.wikipedia.org/wiki/Deafness#cite_note-stroke-mayoclinic-8http://en.wikipedia.org/wiki/Deafness#cite_note-stroke-mayoclinic-8http://en.wikipedia.org/wiki/Aminoglycosidehttp://en.wikipedia.org/wiki/Aminoglycosidehttp://en.wikipedia.org/wiki/Aminoglycosidehttp://en.wikipedia.org/wiki/Gentamicinhttp://en.wikipedia.org/wiki/Gentamicinhttp://en.wikipedia.org/wiki/Gentamicinhttp://en.wikipedia.org/wiki/Cisplatinhttp://en.wikipedia.org/wiki/Cisplatinhttp://en.wikipedia.org/wiki/Cisplatinhttp://en.wikipedia.org/wiki/Diureticshttp://en.wikipedia.org/wiki/Aspirinhttp://en.wikipedia.org/wiki/Macrolide_antibioticshttp://en.wikipedia.org/wiki/Macrolide_antibioticshttp://en.wikipedia.org/wiki/Macrolide_antibioticshttp://en.wikipedia.org/wiki/Hydrocodonehttp://en.wikipedia.org/wiki/Hydrocodonehttp://en.wikipedia.org/wiki/Hydrocodonehttp://en.wikipedia.org/wiki/Rush_Limbaughhttp://en.wikipedia.org/wiki/Rush_Limbaughhttp://en.wikipedia.org/wiki/Rush_Limbaughhttp://en.wikipedia.org/wiki/Oxycodonehttp://en.wikipedia.org/wiki/Oxycodonehttp://en.wikipedia.org/wiki/Oxycodonehttp://en.wikipedia.org/wiki/Leadhttp://en.wikipedia.org/wiki/Leadhttp://en.wikipedia.org/wiki/Leadhttp://en.wikipedia.org/wiki/Solventshttp://en.wikipedia.org/wiki/Solventshttp://en.wikipedia.org/wiki/Solventshttp://en.wikipedia.org/wiki/Toluenehttp://en.wikipedia.org/wiki/Toluenehttp://en.wikipedia.org/wiki/Toluenehttp://en.wikipedia.org/wiki/Crude_oilhttp://en.wikipedia.org/wiki/Crude_oilhttp://en.wikipedia.org/wiki/Crude_oilhttp://en.wikipedia.org/wiki/Gasolinehttp://en.wikipedia.org/wiki/Gasolinehttp://en.wikipedia.org/wiki/Gasolinehttp://en.wikipedia.org/wiki/Gasolinehttp://en.wikipedia.org/wiki/Automobile_exhausthttp://en.wikipedia.org/wiki/Automobile_exhausthttp://en.wikipedia.org/wiki/Deafness#cite_note-tol-nih-11http://en.wikipedia.org/wiki/Deafness#cite_note-tol-nih-11http://en.wikipedia.org/wiki/Deafness#cite_note-tol-nih-11http://en.wikipedia.org/wiki/Asphyxiant_gashttp://en.wikipedia.org/wiki/Deafness#cite_note-def9-12http://en.wikipedia.org/wiki/Deafness#cite_note-def9-12http://en.wikipedia.org/wiki/Deafness#cite_note-def9-12http://en.wikipedia.org/wiki/Ototoxichttp://en.wikipedia.org/wiki/Ototoxichttp://en.wikipedia.org/wiki/Ototoxichttp://en.wikipedia.org/wiki/Hearing_losshttp://en.wikipedia.org/wiki/Hearing_losshttp://en.wikipedia.org/wiki/Deafness#cite_note-def9-12http://en.wikipedia.org/wiki/Deafness#cite_note-def9-12http://en.wikipedia.org/wiki/Deafness#cite_note-def9-12http://en.wikipedia.org/wiki/Cochleahttp://en.wikipedia.org/wiki/Cochleahttp://en.wikipedia.org/wiki/Cochleahttp://en.wikipedia.org/wiki/Auditory_systemhttp://en.wikipedia.org/wiki/Auditory_systemhttp://en.wikipedia.org/wiki/Deafness#cite_note-def9-12http://en.wikipedia.org/wiki/Deafness#cite_note-def9-12http://en.wikipedia.org/wiki/Deafness#cite_note-def9-12http://en.wikipedia.org/wiki/Deafness#cite_note-tm-13http://en.wikipedia.org/wiki/Deafness#cite_note-tm-13http://en.wikipedia.org/wiki/Deafness#cite_note-tm-13http://en.wikipedia.org/wiki/Noisehttp://en.wikipedia.org/wiki/Noisehttp://en.wikipedia.org/wiki/Noisehttp://en.wikipedia.org/wiki/Hearing_protectorshttp://en.wikipedia.org/wiki/Hearing_protectorshttp://en.wikipedia.org/wiki/Hearing_protectorshttp://en.wikipedia.org/wiki/Hearing_protectorshttp://en.wikipedia.org/wiki/Deafness#cite_note-tm-13http://en.wikipedia.org/wiki/Deafness#cite_note-tm-13http://en.wikipedia.org/wiki/Deafness#cite_note-tm-13http://en.wikipedia.org/wiki/Antimalarial_drughttp://en.wikipedia.org/wiki/Antibioticshttp://en.wikipedia.org/wiki/Anti-inflammatoryhttp://en.wikipedia.org/wiki/Antineoplastichttp://en.wikipedia.org/wiki/Diureticshttp://en.wikipedia.org/wiki/Diureticshttp://en.wikipedia.org/wiki/Antineoplastichttp://en.wikipedia.org/wiki/Anti-inflammatoryhttp://en.wikipedia.org/wiki/Antibioticshttp://en.wikipedia.org/wiki/Antimalarial_drughttp://en.wikipedia.org/wiki/Deafness#cite_note-tm-13http://en.wikipedia.org/wiki/Hearing_protectorshttp://en.wikipedia.org/wiki/Hearing_protectorshttp://en.wikipedia.org/wiki/Noisehttp://en.wikipedia.org/wiki/Deafness#cite_note-tm-13http://en.wikipedia.org/wiki/Deafness#cite_note-def9-12http://en.wikipedia.org/wiki/Auditory_systemhttp://en.wikipedia.org/wiki/Cochleahttp://en.wikipedia.org/wiki/Deafness#cite_note-def9-12http://en.wikipedia.org/wiki/Hearing_losshttp://en.wikipedia.org/wiki/Ototoxichttp://en.wikipedia.org/wiki/Deafness#cite_note-def9-12http://en.wikipedia.org/wiki/Asphyxiant_gashttp://en.wikipedia.org/wiki/Deafness#cite_note-tol-nih-11http://en.wikipedia.org/wiki/Automobile_exhausthttp://en.wikipedia.org/wiki/Gasolinehttp://en.wikipedia.org/wiki/Gasolinehttp://en.wikipedia.org/wiki/Crude_oilhttp://en.wikipedia.org/wiki/Toluenehttp://en.wikipedia.org/wiki/Solventshttp://en.wikipedia.org/wiki/Leadhttp://en.wikipedia.org/wiki/Oxycodonehttp://en.wikipedia.org/wiki/Rush_Limbaughhttp://en.wikipedia.org/wiki/Hydrocodonehttp://en.wikipedia.org/wiki/Macrolide_antibioticshttp://en.wikipedia.org/wiki/Aspirinhttp://en.wikipedia.org/wiki/Diureticshttp://en.wikipedia.org/wiki/Cisplatinhttp://en.wikipedia.org/wiki/Gentamicinhttp://en.wikipedia.org/wiki/Aminoglycosidehttp://en.wikipedia.org/wiki/Deafness#cite_note-stroke-mayoclinic-8http://en.wikipedia.org/wiki/Strokehttp://en.wikipedia.org/wiki/Myelin_sheathhttp://en.wikipedia.org/wiki/Autoimmune_diseasehttp://en.wikipedia.org/wiki/Multiple_sclerosis

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Solvents

ethyl benzene, white spirits/Stoddard, carbon

disulfide, fuels, perchloroethylene, trichloroethylene, p-xylene

Asphyxiants

carbon monoxide,hydrogen cyanide

Metals

lead,mercury,organotins(trimethyltin)

Pesticides/Herbicides

paraquat,organophosphates

9. Trauma

Trauma such as a blasting force, a blunt injury to the side of the head, or sudden changes

in atmospheric pressure can cause the tympanic membrane to perforate and middle ear ossicles to

fracture. Blast injuries cause injury from the direct pressure on the ear. Blunt injury to the head

can cause temporal skull fractures and trauma to both the middle and inner ear. Barotrauma

caused by sudden changes in atmospheric pressure in the ears can occur during scuba diving and

airplane takeoffs and landings. Pressure changes can occur during normal atmospheric conditions

such as nose blowing, heavy lifting, and sneezing. During these rapid changes of pressure, the

eustachian tube does not ventilate because of occlusion or dysfunction and a negative pressure

develops in the middle ear. The resulting pressure can cause the tympanic membrane to rupture or

cause damage to the middle and inner ear.

10.Otosclerosis

Otosclerosis, or hardening of the ear, results from the formation of new bone along the

stapes. With the new bone growth, the stapes becomes immobile and causes conductive hearing

loss. The formation of the new bone growth begins in adolescence or early adulthood andprogresses slowly. Hearing loss is most apparent after the fourth decade. Otosclerosis is more

common in women than in men. The disease usually affects both ears. Although the exact cause

of otosclerosis is not known, most patients have a family history of the disease. It is therefore

thought to be a hereditary disease.

11.Masses

Benign masses of the external ear are usually cysts resulting from sebaceous glands.

Other benign masses are lipomas, warts, keloids, and infectious polyps. Infectious polyps usually

arise from the middle ear and enter the external ear through a hole in the tympanic membrane.

Actinic keratosis is a precancerous lesion that can be found on the auricle and may be seen in the

elderly. Malignant tumors such as basal cell carcinoma on the pinna and squamous cell in the ear

canal may develop. These tumors can spread to surrounding tissue and bones if not treated.

Inner ear tumors can be benign or malignant. Acoustic neuroma, a tumor of the eighth

cranial nerve, is the most common benign tumor. It is slow growing, occurs at any age, and

usually occurs unilaterally. As it spreads, it compresses the nerve and adjacent structures.

http://en.wikipedia.org/wiki/Diureticshttp://en.wikipedia.org/wiki/Diureticshttp://en.wikipedia.org/wiki/Solventshttp://en.wikipedia.org/wiki/Solventshttp://en.wikipedia.org/wiki/Ethyl_benzenehttp://en.wikipedia.org/wiki/White_spirithttp://en.wikipedia.org/wiki/Carbon_disulfidehttp://en.wikipedia.org/wiki/Carbon_disulfidehttp://en.wikipedia.org/wiki/Fuelshttp://en.wikipedia.org/wiki/Perchloroethylenehttp://en.wikipedia.org/wiki/Trichloroethylenehttp://en.wikipedia.org/wiki/P-xylenehttp://en.wikipedia.org/wiki/Carbon_monoxidehttp://en.wikipedia.org/wiki/Carbon_monoxidehttp://en.wikipedia.org/wiki/Hydrogen_cyanidehttp://en.wikipedia.org/wiki/Hydrogen_cyanidehttp://en.wikipedia.org/wiki/Hydrogen_cyanidehttp://en.wikipedia.org/wiki/Mercury_(element)http://en.wikipedia.org/wiki/Mercury_(element)http://en.wikipedia.org/wiki/Mercury_(element)http://en.wikipedia.org/wiki/Organotinhttp://en.wikipedia.org/wiki/Organotinhttp://en.wikipedia.org/wiki/Organotinhttp://en.wikipedia.org/wiki/Pesticideshttp://en.wikipedia.org/wiki/Herbicideshttp://en.wikipedia.org/wiki/Herbicideshttp://en.wikipedia.org/wiki/Herbicideshttp://en.wikipedia.org/wiki/Paraquathttp://en.wikipedia.org/wiki/Paraquathttp://en.wikipedia.org/wiki/Organophosphateshttp://en.wikipedia.org/wiki/Organophosphateshttp://en.wikipedia.org/wiki/Organophosphateshttp://en.wikipedia.org/wiki/Organophosphateshttp://en.wikipedia.org/wiki/Paraquathttp://en.wikipedia.org/wiki/Herbicideshttp://en.wikipedia.org/wiki/Pesticideshttp://en.wikipedia.org/wiki/Organotinhttp://en.wikipedia.org/wiki/Mercury_(element)http://en.wikipedia.org/wiki/Hydrogen_cyanidehttp://en.wikipedia.org/wiki/Carbon_monoxidehttp://en.wikipedia.org/wiki/P-xylenehttp://en.wikipedia.org/wiki/Trichloroethylenehttp://en.wikipedia.org/wiki/Perchloroethylenehttp://en.wikipedia.org/wiki/Fuelshttp://en.wikipedia.org/wiki/Carbon_disulfidehttp://en.wikipedia.org/wiki/Carbon_disulfidehttp://en.wikipedia.org/wiki/White_spirithttp://en.wikipedia.org/wiki/Ethyl_benzenehttp://en.wikipedia.org/wiki/Solvents

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Malignant tumors arising from the inner ear are rare. Squamous and basal carcinomas arise from

the epidermal lining of the inner ear.

CLINICAL MANIFESTATIONS

Deafness is often called as unseen handicap because it is not known until conversation is

initiated with a deaf human

Microtia in congenital deafness

Often patients are unaware about minimal hearing loss or may compensate by mannerism

Asking Others To Speak Up

Answering questioning un-appropriately

Not responding when looking at speaker

Straining to hear

Cupping hand around ear

Showing irritability towards other who do not speak up

Increasing in sensitivity to slight increase in noise level

Speaking loudly as compared to others

Increased in susceptibility

Delaying in responding to any questions or phrases.

Loss of self esteem

Insecurity

Frustration

Lack of concentration

Misjudgment (pt. may gear what is said but may not understand it)

DIAGNOSTIC EVALUATION

History collection

Physical examination

Whispered speech test: Whisper a combination of numbers and letters behind the patient and

check if he can hear anything by asking the patient to repeat the combination. if unilateral

deafness is suspected the good ear should be masked and the deaf ear tested

RINNES TEST

Air Conduction > Bone Conduction = normal or SNHL

Bone Conduction > Air Conduction = Conductive HL or dead ear

WEBERS TEST

In conductive deafness the sound is heard loudest in the affected ear.

In sensorineural deafness the sound is heard louder in the un affected ear.

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AUDIOMETRY

Pure tone audiometry (PTA).

It is the keyhearing testused to identifyhearingthreshold levels of an individual .

the lower the threshold the better hearing.

AC threshold are obtained with headphones and measure outer , middle, inner ear and

the auditory nerve function.

BC threshold are obtained with bone conduction oscillators which effectively bypass

outer and middle ear function

0 dB - 20 dB ....... normal hearing

20 dB - 40 dB ..... mild hearing loss

40 dB - 55 dB ..... moderate hearing loss

55 dB - 70 dB ..... moderately severe hearing loss

70 dB - 90 dB ..... severe hearing loss

>90 dB................. profound hearing loss

CONDUCTIVE HEARING LOSS

bone conduction threshold in normal rang .

air conduction threshold outside of normal limits.

gap between AC and BC threshold > 10 db ( air bone gab ).

SENSORINEURAL HEARING LOSS

both air and bone conduction threshold below normal .

gap between AC and BC less 10 db ( no air bone gap).

Computed tomography

MRI

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Tympanometry

May be indicated if a problem with the tympanic membrane (eardrum) is suspected. This test

evaluates the middle ears ability to receive sound waves.Tympanometry provides a graph of the

middle ear's ability to transmit sound energy (admittance, or compliance) or impede sound

energy (impedance) as a function of air pressure in the external ear canal. Because most

immittance test instruments measure acoustic admittance, the term admittance is used here.

The principles apply to whatever units of measurement are used.

A probe is inserted into the entrance of the external ear canal so that an airtight seal is

obtained. The probe varies air pressure, presents a tone, and measures sound pressure level in

the ear canal through the probe assembly. The sound pressure measured in the ear canal

relative to the known intensity of the probe signal is used to estimate the acoustic admittance of

the ear canal and middle-ear system. Admittance can be expressed in a unit called a millimho

(mmho) or as a volume of air (mL) with equivalent acoustic admittance. The test is performed so

that an estimate can be made of the volume of air enclosed between the probe tip and TM. The

acoustic admittance of this volume of air is deducted from the overall admittance measure to

obtain a measure of the admittance of the middle-ear system alone. Estimating ear canal

volume also has a diagnostic benefit, because an abnormally large value is consistent with the

presence of an opening in the TM (perforation or tube).

Once the admittance of the air mass in the external auditory canal has been eliminated, it is

assumed that the remaining admittance measure accurately reflects the admittance of the

entire middle-ear system. Its value is controlled largely by the dynamics of the TM.

Abnormalities of the TM can dictate the shape of tympanograms, thus obscuring abnormalities

medial to the TM. In addition, the frequency of the probe tone, the speed and direction of the

air pressure change, and the air pressure at which the tympanogram is initiated can all influence

the outcome.

When air pressure in the ear canal is equal to that in the middle ear, the middle-ear system is

functioning optimally. Therefore, the ear canal pressure at which there is the greatest flow of

energy (admittance) should be a reasonable estimate of the air pressure in the middle-ear

space. This pressure is determined by finding the maximum or peak admittance on the

tympanogram and obtaining its value on the x-axis. The value on the y-axis at the tympanogram

peak is an estimate of peak admittance based on admittance tympanometry ( Table 636-8 ). This

peak measure sometimes is referred to as static acoustic admittance, even though it is

estimated from a dynamic measure

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MEDICAL MANAGEMENT

Corticosteroids in small doses sometimes decrease the edema of the Eustachian tube in cases of

barotraumas. Decongestants have not proved effective.

A Valsalva maneuver, which forcibly opens the eustachian tube by increasing nasopharyngeal pressure,

may be cautiously performed. Performing the Valsalva maneuver may cause worsening pain or perforation of the

tympanic membrane.Symptomatic treatment is done

SURGICAL MANAGEMENT

TYMPANOPLASTY surgical repair of the tympanic membrane.

The most common surgical procedure for chronic otitis media is a tympanoplasty, or surgical reconstruction of the

tympanic membrane. Reconstruction of the ossicles may also be required. The purposes of a tympanoplasty are to

reestablish middle ear function, close the perforation, prevent recurrent infection, and improve hearing. There are

five types of tympanoplasties. The simplest surgical procedure, type I (myringoplasty), is designed to close a

perforation in the tympanic membrane. The other procedures, types II through V, involve more extensive repair of

middle ear structures.The structures and the degree of involvement can differ, but all tympanoplasty procedures include restoring the

continuity of the sound conduction mechanism.

Tympanoplasty is performed through the external auditory canal with a transcanal approach or through a

postauricular incision. The contents of the middle ear are carefully inspected, and the ossicular chain is evaluated.

Ossicular interruption is most frequent in chronic otitis media, but problems of reconstruction can also occur with

malformations of the middle ear and ossicular dislocations due to head injuries. Dramatic improvement in hearing

can result from closure of a perforation and Re-establishment of the ossicles. Surgery is usually performed in an

outpatient environment under moderate sedation or general

anesthesia.

OSSICULOPLASTY.

Many people use the term tympanoplasty to include ossiculoplasty, or surgical reconstruction of the middle ear

bones to restore hearing. Prostheses made of materials such as Teflon, stainless steel, and hydroxyapatite is used to

reconnect the ossicles, thereby reestablishing the sound conduction mechanism. However, the greater the damage,

the lower the success rate for restoring normal hearing

MASTOIDECTOMY.

The objectives of mastoid surgery are to remove the cholesteatoma, gain access to diseased structures, and create a

dry and healthy ear. If possible, the ossicles are reconstructed during the initial surgical procedure. Occasionally,

extensive disease dictates that this be performed as part of a planned second-stage operation.

A mastoidectomy is usually performed through a postauricular incision. Infection is eliminated by removing the

mastoid air cells. Although infrequently injured, the facial nerve, which runs through the middle ear and mastoid, is

at some risk for injury during mastoid surgery. As the patient awakens from anesthesia, any evidence of facialparesis should be reported to the physician.

A second mastoidectomy may be necessary to check for recurrent or residual cholesteatoma. The hearing

mechanism may be reconstructed at this time. The success rate for correcting this conductive hearing loss is

approximately 75%. Surgery is usually performed in an outpatient setting. The patient has a mastoid pressure

dressing, which can be removed 24 to 48 hours after surgery.

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STAPEDECTOMY

A stapedectomy, performed through the canal, involves removing the stapes superstructure and part of the footplate

and inserting a tissue graft and a suitable prosthesis (Fig. 59-8). Some surgeons elect to remove only a small part of

the stapes footplate (ie, stapedotomy). Regardless of the method used, the prosthesis bridges the gap between the

incus and the inner ear, providing better sound conduction. Stapes surgery is very successful in improving hearing.

Balance disturbance or true vertigo, which rarely occurs in other middle ear surgical procedures, can occur for a

short time after stapedectomy.

Removing CerumenInstillations and irrigations should not be used on any person with a history of perforated tympanic membrane.Commercial ceruminolytics or common products such as baby oil, mineral oil, and virgin olive oil can be used to

soften impacted cerumen and aid in the removal of the impacted wax. The patient should instill several drops of the

solution at bedtime and then place a cotton plug in the ear to hold the solution in place. Excess oil and drainage are

removed in the morning. Earwax is usually softened for 3 to 4 days before an irrigation is attempted. Patients prone

to cerumen build-up should be taught how to safety remove earwax. A few drops of half-strength peroxide may be

instilled into the ear canal during the day and three drops of glycerine instilled at bedtime. This can be repeated each

week to minimize wax build-up.

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The ear can be irrigated with an ear irrigation syringe or a Water Pik. The irrigation solution, usually water, should

be warmed to body temperature. The patient is draped with a protective plastic drape, and a basin is placed below

the ear to catch the irrigating solution. The patient sits with the ear toward the nurse and the head tilted toward the

opposite ear. The external ear is pulled upward and backward for the adult. A low-pressure stream of water is

directed toward the top of the ear canal. Care is taken not to obstruct the canal with the syringe so that the irrigation

solutions can flow back out of the canal. Ensure that only the tip of the syringe is in the ear canal to prevent

perforation of the eardrum.

NURSING MANAGEMENT

Application of theory

Transcultural nursing theory, Madeleine Leininger is considered as the founder of the theory of

transcultural nursing

It mostly focuses on communication

APPLICATION TO NURSING

To develop understanding, respect and appreciation for the individuality and diversity of

patients beliefs, values, spirituality and culture regarding illness, its meaning, cause, treatment,and outcome.

To encourage in developing and maintaining a program of physical, emotional and spiritual self-

care introduce therapies such as ayurveda and pancha karma.

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To care of patients who are deaf or hard of hearing (Gustafson, 2005; Leininger & McFarland, 2002).

Focusing on the processes with which nursing care is provided, transcultural theory includes within

its definition of cultural competence the individual attitudes, skills, and practices that frame the ways

in which communication is patterned between nurses -and their patients. These processes need to

be examined specifically and adapted (Hartrick Doane & Varcoe, 2005) to ensure that the particular

needs of individual deaf patients are respected, in accord with their self-perceptions of identity andtheir membership in the Deaf community (McLeod & Bently, 1996; Stebnicki & Coeling, 1999)

The nurse must first become knowledgeable about the differences between being deaf and being a

member of the Deaf community. Deaf persons generally deem themselves to be members of the

Deaf community (upper-case D), using a unique language (ASL) and adherence to certain social

and cultural behaviors.

Deaf Patients.

Look directly at the patient when speaking with him/her. Do not cover your mouth when speaking because the patient may read lips. If the patient does not lip-read, charts with pictures may be used, or simply writing your questions

or comments on a piece of paper may be helpful. Charts with hand signs are available at the local society for deafness and/or hearing preservation.

1) Impaired sensory perception: auditory related to impairment of sensory reception andtransmission, damage to vestibular or cochlear nerve.

Expected Outcomes Patient will attain optimum level of sensory stimulation. Patient will becomeaware of auditory impairment and ways to compensate. Patient will demonstrate ability to performactivities of daily living, with assistance if necessary.

Interventions Begin assessment of hearing by inspecting ear canals for mechanical obstruction. If cerumen is

found, the use of a softening product is recommended to assist in wax removal. If canal is clear,continue assessment of hearing by use of a tuning fork, loud ticking clock, or verbal cues todetermine auditory ability at various distances.

Enhance hearing by giving auditory cues in quiet surroundings.

Enhance understanding of auditory cues by getting patients attention before speaking, speakslowly with careful enunciation of words, add hand gestures, speak face to face with impairedperson, and adjust pitch downward without increasing volume.

Structure environment to compensate for hearing loss by adding visual indicators to telephoneringer, doorbell, smoke detectors, and other emergency sounds.

Provide for optimum care of assistive appliances such as hearing aids by making sure thatcerumen has been cleaned from the device, that batteries are charged, and that appliance is

placed correctly in ear.

2) Impaired communication related to hearing loss

Expected outcome : to improve the communication.

Interventions

Look directly at the patient when speaking with him/her.

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Do not cover your mouth when speaking because the patient may read lips. If the patient does not lip-read, charts with pictures may be used, or simply writing your questions

or comments on a piece of paper may be helpful. Charts with hand signs are available at the local society for deafness and/or hearing preservation.

BIBLIOGRAPHY:-

1. Lewis, Heitkemper & Dirksen (2000) Medical Surgical Nursing Assessment and

Management of Clinical Problem (7th

ed) Mosby, pg no. 1856-61.

2. Black J.M. Hawk, J.H. (2005) Medical Surgical Nursing Clinical Management for

Positive Outcomes. (7th ed) Elsevier, pg no. 2011-14.

3. Brunner S. B., Suddarth D.S. The Lippincott Manual of Nursing practiceJ.B.Lippincott. Philadelphia, pg no. 1549-59

4. Understanding medical surgical nursing, F A Davis 6th edition, elsieiver publication

pg. no. 210-224.

5. www.ncbi.org/deafness20%community.html

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