Auditory Disorders
Auditory Disorders
Auditory Disorders
Acena, Jobelle C.
At first glance, the machinery for hearing and balance appears very crude.
Anatomically, the ear is divided into three major areas: the external, or outer, ear; the middle ear,
and the internal, or inner, ear.
The external, or outer, ear is composed of the auricle and the external acoustic meatus.
Auricle. The auricle, or pinna, is what most people call the “ear”- the shell-shaped
structure surrounding the auditory canal opening.
External acoustic meatus. The external acoustic meatus is a short, narrow chamber
carved into the temporal bone of the skull; in its skin-lined walls are the ceruminous
glands, which secrete waxy, yellow cerumen or earwax, which provides a sticky trap for
foreign bodies and repels insects.
Tympanic membrane. Sound waves entering the auditory canal eventually hit the
tympanic membrane, or eardrum, and cause it to vibrate; the canal ends at the ear drum,
which separates the external from the middle ear.
Middle Ear
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The middle ear, or tympanic cavity, is a small, air-filled, mucosa-lined cavity within the temporal
bone.
The internal ear is a maze of bony chambers, called the bony, or osseous, labyrinth, located deep
within the temporal bone behind the eye socket.
Subdivisions. The three subdivisions of the bony labyrinth are the spiraling, pea-sized
cochlea, the vestibule, and the semicircular canals.
Perilymph. The bony labyrinth is filled with a plasma-like fluid called perilymph.
Membranous labyrinth. Suspended in the perilymph is a membranous labyrinth, a
system of membrane sacs that more or less follows the shape of the bony labyrinth.
Endolymph. The membranous labyrinth itself contains a thicker fluid called endolymph.
Mechanisms of Equilibrium
Static Equilibrium
Maculae. The maculae report on changes in the position of the head in space with respect
to the pull of gravity when the body is not moving.
Otolithic hair membrane. Each macula is a patch of receptor (hair) cells with their
“hairs” embedded in the otolithic hair membrane, a jelly-like mass studded with otoliths,
tiny stones made of calcium salts.
Otoliths. As the head moves, the otoliths roll in response to changes in the pull of
gravity; this movement creates a pull on the gel, which in turn slides like a greased plate
over the hair cells, bending their hairs.
Vestibular nerve. This event activates the hair cells, which send impulses along the
vestibular nerve (a division of cranial nerve VIII) to the cerebellum of the brain,
informing it of the position of the head in space.
Dynamic Equilibrium
The dynamic equilibrium receptors, found in the semicircular canals, respond to angular or
rotatory movements of the head rather than to straight-line movements.
Semicircular canals. The semicircular canals are oriented in the three planes of space;
thus regardless of which plane one moves in, there will be receptors to detect the
movement.
Crista ampullaris. Within the ampulla, a swollen region at the base of each membranous
semicircular canal is a receptor region called crista ampullaris, or simply crista, which
consists of a tuft of hair cells covered with a gelatinous cap called the cupula.
Head movements. When the head moves in an arclike or angular direction, the
endolymph in the canal lags behind.
Bending of the cupula. Then, as the cupula drags against the stationary endolymph, the
cupula bends- like a swinging door- with the body’s motion.
Vestibular nerve. This stimulates the hair cells, and impulses are transmitted up the
vestibular nerve to the cerebellum.
Mechanism of Hearing
The following is the route of sound waves through the ear and activation of the cochlear hair
cells.
Vibrations. To excite the hair cells in the organ of Corti in the inner ear, sound wave
vibrations must pass through air, membranes, bone and fluid.
Sound transmission. The cochlea is drawn as though it were uncoiled to make the events
of sound transmission occurring there easier to follow.
Low frequency sound waves. Sound waves of low frequency that are below the level of
hearing travel entirely around the cochlear duct without exciting hair cells.
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High frequency sound waves. But sounds of higher frequency result in pressure waves
that penetrate through the cochlear duct and basilar membrane to reach the scala tympani;
this causes the basilar membrane to vibrate maximally in certain areas in response to
certain frequencies of sound, stimulating particular hair cells and sensory neurons.
Length of fibers. The length of the fibers spanning the basilar membrane tune specific
regions to vibrate at specific frequencies; the higher notes- 20, 000 Hertz (Hz)- are
detected by shorter hair cells along the base of the basilar membrane.
A. ASSESSMENT
1. SUBJECTIVE DATA
a. Nursing History
Sebaceous cyst behind the ear - A sebaceous cyst is a rounded swollen area of the
skin formed by an abnormal sac of retained excretion (sebum) from the sebaceous
follicles.
Tophi - A nodular mass of uric acid crystals. Tophi are characteristically deposited in
different soft tissue areas of the body in chronic (tophaceous) gout. Even though tophi
are most commonly found as hard nodules around the fingers, at the tips of the
elbows, and around the big toe, they can appear anywhere in the body. They have
been reported in unexpected areas such as in the ears, in the vocal cords, and around
the spinal cord.
Impacted Cerumen - when earwax (cerumen) builds up in the ear and blocks the ear
canal; it can cause temporary hearing loss and ear pain.
Discharge in the canal - Ear discharge, also known as otorrhea, is any fluid that
comes from the ear.
Swelling of pinna, pain - Perichondritis of the ear can be a diffuse inflammatory, but
not necessarily infectious, process resulting in diffuse swelling, redness, and pain of
the pinna, or an abscess between the cartilage and the perichondrium.
Scalling of lesions - Scaling skin is dry, cracked, or flaky skin. Also known as
desquamation, scaling skin happens when the outer layer of the skin, called the
epidermis, begins to flake off. Scaling skin may arise when an injury or a medical
condition damages the outer layer of skin.
Exostosis - also known as bone spur, is the formation of new bone on the surface of a
bone. Exostoses can cause chronic pain ranging from mild to debilitatingly severe,
depending on the shape, size, and location of the lesion.
Retracted, bulging perforated eardrum - eardrum gets pushed inward toward your
middle ear
Interpretation
Screening assessments
o Whispered voice test: While standing behind the patient, whisper a phrase or numbers in
each ear → Ask the patient to repeat what you whispered.
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o Finger rub test: Place your fingers several centimeters from either ear → Rub your
fingertips together and ask the patient if they heard it.
Interpretation
Rinne test: tests for air conduction vs bone conduction in the examined ear
o Place the base of a vibrating tuning fork on the mastoid process of the
ear. Once the patient no longer hears a tone, immediately hold the
“U” part of the fork over the outer ear and ask the patient if they can
still hear it.
o Air conduction is normally greater than bone conduction, so the
patient should still be able to hear the tuning fork next to the outer
ear after they can no longer hear it when placed on the mastoid
process.
Interpretation
2. Diagnostic Assessment
Non-invasive Test
sound stimulus consists of a pure or musical tone (the louder the tone
before the patient perceives it, the greater the hearing loss), and speech
audiometry, in which the spoken word is used to determine the ability to
hear and discriminate sounds and words.
Audiography
o Weber
The Weber test uses bone conduction to test lateralization of sound. A
tuning fork (ideally, 512 Hz), set in motion by grasping it firmly by its
stem and tapping it on the examiner’s knee or hand, is placed on the
patient’s head or forehead. A person with normal hearing will hear the
sound equally in both ears or describe the sound as centered in the middle
of the head. In cases of conductive hearing loss, such as from otosclerosis
or otitis media, the sound is heard better in the affected ear. In cases of
sensorineural hearing loss, resulting from damage to the cochlear or
vestibulocochlear nerve, the sound lateralizes to the better-hearing ear.
The Weber test is useful for detecting unilateral hearing loss
o Rinne
In the Rinne test (pronounced rin-ay), the examiner shifts the stem of a
vibrating tuning fork between two positions: 2 inches from the opening of
the ear canal (ie, for air conduction) and against the mastoid bone (ie, for
bone conduction) (Fig. 59-6). As the position changes, the patient is asked
to indicate which tone is louder or when the tone is no longer audible.
Normally, sound heard by air conduction is audible longer than sound
heard by bone conduction. The Rinne test is useful for distinguishing
between conductive and sensorineural hearing losses. With a conductive
hearing loss, bone-conducted sound is heard as long as or longer than air-
conducted sound, whereas with a sensorineural hearing loss, air-conducted
sound is audible longer than bone conducted sound. In a normal hearing
ear, air-conducted sound is louder than bone-conducted sound.
o Tympanometry
A tympanogram, or impedance audiometry, measures middle ear muscle
reflex to sound stimulation and compliance of the tympanic membrane by
changing the air pressure in a sealed ear canal. Compliance is impaired
with middle ear disease.
o Brain Stem responses
The auditory brain stem response is a detectable electrical potential from
cranial nerve VIII and the ascending auditory pathways of the brain stem
in response to sound stimulation. Electrodes are placed on the patient’s
forehead. Acoustic stimuli, usually in the form of clicks, are made in the
ear. The resulting electrophysiologic measurements can determine at
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which decibel level a patient hears and whether there are any impairments
along the nerve pathways (eg, tumor on cranial nerve VIII).
Electroencephalography
Oto-acoustic emissions
o Test for Vestibular Function
Platform post urography
Platform posturography is used to investigate postural control
capabilities. The integration of visual, vestibular, and proprioceptive
cues (ie, sensory integration) with motor response output and
coordination of the lower limbs is tested. The patient stands on a
platform, surrounded by a screen, and different conditions such as a
moving platform with a moving screen or a stationary platform with
a moving screen are presented. The responses from the patient on
six different conditions are measured and indicate which of the
anatomic systems may be impaired. Preparation for the testing is the
same as for electronystagmography.
Rota chair assessment
Sinusoidal harmonic acceleration, or a rotary chair, is used to assess
the vestibulo-ocular system by analyzing compensatory eye
movements in response to the clockwise and counter clockwise
rotation of the chair. Although such testing cannot identify the side
of the lesion in unilateral disease, it helps identify disease and
evaluate the course of recovery. The same patient preparation is
required as for electronystagmography.
Invasive Test
Arteriography
Test for vestibular function
o Electro-nystagmography
Electronystagmography is the measurement and graphic recording
of the changes in electrical potentials created by eye movements
during spontaneous, positional, or calorically evoked nystagmus.
Laboratory Tests
Blood Tests.
Cultures (ear drainage)
Test for the presence of CSF
Tissue specimen
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External Otitis
o External otitis, or otitis externa, refers to an inflammation of the external
auditory canal. Causes include water in the ear canal (ie, swimmer’s ear);
trauma to the skin of the ear canal, permitting entrance of organisms into the
tissues; and systemic conditions, such as vitamin deficiency and endocrine
disorders.
Obstruction Cerumen
o Cerumen normally accumulates in the external canal in various amounts and
colors. Although wax does not usually need to be removed, impaction
occasionally occurs, causing otalgia, a sensation of fullness or pain in the ear,
with or without a hearing loss. Accumulation of cerumen is especially
significant in the geriatric population as a cause of hearing deficit.
Foreign Bodies
o Some objects are inserted intentionally into the ear by adults who may have
been trying to clean the external canal or relieve itching or by children who
introduce the objects. Other objects, such as insects, peas, beans, pebbles,
toys, and beads, may enter or be introduced into the ear canal. In either case,
the effects may range from no symptoms to profound pain and decreased
hearing.
Otitis Media
o Acute
Acute otitis media is an acute infection of the middle ear, usually
lasting less than 6 weeks. The primary cause of acute otitis media is
usually Streptococcus pneumoniae, Haemophilus influenzae, and
Moraxella catarrhalis, which enter the middle ear after eustachian tube
dysfunction caused by obstruction related to upper respiratory
infections, inflammation of surrounding structures (eg, sinusitis,
adenoid hypertrophy), or allergic reactions (eg, allergic rhinitis).
Bacteria can enter the eustachian tube from contaminated secretions in
the nasopharynx and the middle ear from a tympanic membrane
perforation. A purulent exudate is usually present in the middle ear,
resulting in a conductive hearing loss.
o Chronic
Chronic otitis media is the result of repeated episodes of acute otitis
media causing irreversible tissue pathology and persistent perforation
of the tympanic membrane. Chronic infections of the middle ear
damage the tympanic membrane, destroy the ossicles, and involve the
mastoid. Before the discovery of antibiotics, infections of the mastoid
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E. IMPLEMENTATION
1. Pharmacological Therapeutics
Anti-infective
Anti-inflammatory agents
Anti-glaucoma agents
Mydriatics
Local anesthetics
a. Bilberry
4. Client Education
Disease process
Physical Activity
Meal Planning
Medication Compliance
Monitoring Laboratory Tests
Risk Reduction
Psychosocial
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References
Layug, E., (2009). Client with Visual Disorders, Pages 1059-1073, Comprehensive Reviewer for
the Nurse Licensure Exam (NLE), 839 EDSA, South Triangle, Quezon City, C & E
Publishing, Inc.
Lowth, M. MD, (February 2017). Nystagmus, Doctor Patient. Retrieved on June 3, 2020 from
https://patient.info/doctor/nystagmus#nav-5
https://www.physio-pedia.com/Romberg_Test
https://www.amboss.com/us/knowledge/Head_and_neck_examination
Smeltzer, S., Bare, B., Hinkle, J., & Cheever, H. (2008). Brunner & Suddarth’s Textbook of
Special Senses Anatomy and Physiology, Nurseslabs. Retrieved on June 3, 2020 from
https://nurseslabs.com/special-senses-anatomy-physiology/
Watson, S. (May 14, 2018). Retracted Eardrum, Healthline. Retrieved on June 3, 2020 from
https://www.healthline.com/health/retracted-eardrum