Definition
A.Impaired hearing (complete or partial hearing loss) results from interference with the conduction of sound, its conversion to electrical impulses, or its transmission through the nervous system. There are three types of hearing loss:
1.Conductive.
2.Sensorineural.
3.Mixed or combined conductive and sensorineural loss.
Incidence
A.Hearing loss is present in 10% to 15% of patients; over 30 million Americans 18 years of age or older have some degree of hearing impairment.
B.One in three people older than the age of 60 and half of all people older than the age of 85 have hearing deficits.
Pathogenesis
A.Conductive hearing loss (air-bone gap) occurs when sound is not conducted effectively and presents with a diminution of volume, particularly low tones and vowels. It may be caused by one of the following:
1.Otologic processes such as chronic or serous otitis media, otitis externa, foreign body, cerumen impaction, or trauma to the middle ear.
2.Otosclerosis disorder of the architecture of the bony labyrinth, which fixes the footplate of the stapes in the oval window.
3.Exostoses are bony excrescences of the external auditory canal.
4.Glomus tumors are benign, highly vascular tumors derived from normally occurring glomera of the middle ear and jugular bulb.
B.Sensorineural hearing loss occurs after damage to the inner ear or vestibulocochlear nerve and characteristically produces impairment of the high-tone perception. Affected patients can hear people speaking, but they have difficulty deciphering words because discrimination is poor. It may be caused by one of the following:
1.Presbycusis is hearing loss associated with aging and is the most common cause of diminished hearing in the elderly; onset is bilateral, symmetric, and gradual.
2.Noise-induced hearing loss is due to chronic exposure to sound levels in excess of 85 to 90 dB.
3.Drug-induced hearing loss can be caused by aminoglycoside antibiotics, furosemide, ethacrynic acid, quinidine, and aspirin.
4.Ménière’s disease produces a fluctuating, unilateral, low-frequency impairment usually associated with tinnitus, a sensation of fullness in the ear, and intermittent episodes of vertigo.
5.Acoustic neuroma is a benign tumor of the eighth cranial nerve (rare).
6.Sensorineural hearing loss is generally bilateral and symmetric, and it may be genetically determined.
7.Sudden deafness can derive from head trauma, skull fracture, meningitis, otitis media, scarlet fever, mumps, congenital syphilis, multiple sclerosis, and perilymph leaks or fistulas.
Predisposing Factors
A.Acoustic or physical trauma.
B.Ototoxic medications (such as gentamicin and aspirin).
C.Changes in barometric pressures.
D.Recent upper respiratory infection (URI).
E.Pregnancy.
F.Otosclerosis.
G.Nasopharyngeal cancer.
H.Serous otitis media.
I.Cerumen impaction.
J.Foreign body in the ear.
Common Complaints
A.Partial hearing loss.
B.Total hearing loss.
C.Difficulty understanding the television, phone conversations, and people talking.
Other Signs and Symptoms
A.Unilateral or bilateral hearing loss.
B.Hearing noises such as ringing,
buzzing,
and so forth.
C.Fullness in ear(s).
Subjective Data
A.Elicit the onset, duration, progression, and severity of symptoms. Note whether symptoms are bilateral or unilateral.
B.Obtain the patient’s history of past or recent trauma.
C.Review the patient’s occupational and recreational exposure to risk factors.
D.Review the patient’s medical history and medications, including over-the-counter (OTC) drugs and prescriptions.
E.Review the patient’s history for recent URI or ear infections, especially for chronic ear infections.
F.Elicit data about any previous hearing loss, how it was treated, and how it affected daily activities. There is often a history of previous ear disease with conductive hearing loss.
G.Review the patient’s other symptoms such as dizziness, fullness or pressure in the ears, and noises.
H.Review what causes difficulty with hearing, high tones versus low frequencies. Can patient hear people talking, the television at normal volume, doorbells ringing, telephone ringing, and watch ticking?
Physical Examination
A.Inspect:
1.Examine both ears for comparison.
2.Externally inspect ears for discharge; note color and odor. Obstruction of the auditory canal by impacted cerumen, a foreign body, exostoses, external otitis, otitis media with effusion (OME), or scarring or perforation of the eardrum due to chronic otitis may be present.
3.Conduct otoscopic examination to observe the auditory canal for cerumen impaction or foreign body.
4.Inspect tympanic membrane for color, landmarks, contour, perforation, and acute otitis media (AOM). A reddish mass visible through the intact tympanic membrane may indicate a high-riding jugular bulb, an aberrant internal carotid artery, or a glomus tumor.
B.Palpate:
1.Palpate auricle and mastoid area for tenderness, swelling, or nodules.
2.Check lymph nodes if infection is suspected.
C.Neurologic testing: Weber and Rinne tests:
1.In the Weber test, the tuning fork is perceived more loudly in the conductively deaf ear.
2.The Rinne test shows that bone conduction is better than air conduction (normal is when air conduction is greater than bone conduction).
Diagnostic Tests
A.Audiogram in primary setting.
B.Air insufflation for tympanic membrane mobility.
C.Tympanometry brainstem—evoked response audiogram.
D.CT scan or MRI after consultation with an otolaryngologist
Differential Diagnoses
A.Congenital hearing loss.
B.Traumatic hearing loss.
C.Ototoxicity.
D.Presbycusis.
E.Ménière’s syndrome.
F.Acoustic neuroma.
G.Cholesteatoma.
H.Infection.
I.Cerumen impaction.
J.Otitis externa.
K.Foreign body in the ear.
L.Tumors.
M.Otosclerosis.
N.Perforation of tympanic membrane.
O.Serous otitis media.
P.Hypothyroidism.
Q.Paget’s disease.
Plan
A.General interventions: Treat any primary cause (i.e., remove impacted cerumen).
B.Patient teaching:
1.Harmful noise levels should be avoided.
2.Individual hearing protection devices should be utilized in all patients exposed to occupational noise.
C.Pharmaceutical therapy: Treat primary condition if applicable.
Follow-Up
A.If hearing loss is identified and cause is not immediately treatable, refer the patient to otolaryngology for further evaluation.
Consultation/Referral
A.Any sudden onset of hearing loss requires immediate referral.
B.The patient should be referred to an otolaryngologist for an extensive workup when the primary cause cannot be identified.
C.Referral should be made to a hearing aid specialist for hearing evaluation and treatment as indicated (i.e., hearing aids).
Individual Considerations
A.Geriatrics:
1.Impaired hearing among the elderly is common and can lower the quality of life. Up to 80% of those over 85 years have hearing loss.
2.People with seriously impaired hearing often become withdrawn or appear confused.
3.Subtle hearing loss may go unrecognized.
4.Impacted cerumen is very common in the elderly and can be a source of hearing loss.
5.Hearing loss in elderly affects both peripheral and central auditory systems. The highest frequencies are predominantly impacted, which is the area vital to understanding spoken words.
6.Geriatrics with depression and dementia significantly benefit from cochlear implants. Studies have suggested that the enhanced amplification improved behavioral health issues and quality of life. There is a 1% failure rate. Patient selection criteria are the following:
a.Moderate to severe bilateral sensorineural hearing loss.
b.Unilateral deafness with/without ipsilateral tinnitus.
c.Benefit from hearing aids less than expected.
d.No medical contraindication with anesthesia and no active ear infections.
e.Family/surrogate support, motivation, and appropriate expectations.
7.Communicating with elderly who have hearing loss:
a.Ask what is their preference in communication.
b.Stand/sit 2 to 3 feet away with patient sitting in front of a wall to reflect sound.
c.Speak slowly toward the better ear using a lower-pitched voice (do not shout).
d.Rephrase rather than repeat sentences, and pause between each phrase/idea as needed.
8.Elderly patients with dexterity challenges may benefit with user-friendly hearing aid models such as behind-the-ear or in-the-ear types.
9.Patients with advanced cognitive deficits might need specific aids attached to the device and fastened to clothing to prevent loss of hearing aid. Audiologists would assist families/surrogates with safety measures for these attachments.