Deafness

Overview and Facts about Deafness

Hearing loss can be a partial or complete loss of hearing and occurs when any part of the ear — the outer, middle or inner ear or the hearing (acoustic) nerve are not working correctly.

There are three main types of hearing loss:

• Conductive hearing loss occurs when blockage or damage to the outer or middle ear prevents sound from being conducted to the inner ear (the cochlea).
• Sensorineural hearing loss occurs when inner ear nerves become damaged and do not accurately transmit signals to the brain. This is the most common type ofpermanent hearing loss associated with patient’s getting older.
• Mixed hearing loss includes both conductive and a sensorineural hearing loss and occurs from damage in both the outer or middle ear and the inner ear.

Signs and Symptoms of Deafness

Symptoms of hearing loss may be mild, moderate, severe or profound. Depending on the severity, symptoms can range from difficulty hearing soft speech to being unable to hear loud sounds.

Symptoms of conductive hearing loss include:

• Decreased hearing in one ear
• Pain or pressure in one or both ears
• Difficulty hearing speech
• The sense that one’s voice sounds different

Symptoms of sensorineural hearing loss include:

• Noises seeming too loud or too quiet
• Difficulty following a conversation when two or more people are speaking at the same time
• Problems listening in environments with background noise
• The sense that others’ speech is slurred or mumbled
• Ringing in the ears (tinnitus)

Symptoms of mixed hearing loss include a combination of conductive and sensorineural hearing loss symptoms.

Causes and Risk Factors of Deafness

There are several causes of hearing loss, depending on the type. Common causes of conductive hearing loss include:

• Infection of the ear canal or middle ear
• Fluid in the middle ear
• Perforation or scarring of the eardrum
• Wax build-up
• Unusual growths or tumors in the ear
• Otosclerosis, in which there is an abnormal growth of bone in the middle ear

The aging process is a common cause of sensorineural hearing loss. Other causes of this type of hearing loss include:

• Injury
• Excessive noise exposure
• Viral infections, such as measles or mumps
• Meniere's disease
• Benign tumors
• Family history

Mixed hearing loss is caused by a combination of conductive damage in the outer or middle ear and sensorineural damage in the inner ear or auditory nerve.

Tests and Diagnosis of Deafness

There are a variety of tests available to diagnose the type and severity of hearing loss. A few of the tests audiologists and physicians who specialize in otolaryngology (ENT) will perform include:

• Pure-tone testing, which determines the very softest signals one can hear at each of the presented frequencies and indicates frequency regions in which hearing may be impaired.
• Speech testing, which evaluates the ability to both hear and understand normal conversations. Testing may take place in a quiet or noisy setting.

Otoacoustic emissions (OAEs), which are special hearing tests used to determine the function of the inner ear, or cochlea.

Treatment and Care of Deafness

Treatment depends on the cause and severity of hearing loss. There are several options available.

For age-related hearing loss, hearing aids and other listening devices help treat the problem and improve quality of life.

Those who are severely hard of hearing may benefit from a cochlear implant, a small electronic device that is surgically implanted to provide a sense of sound.