Hearing loss is a decrease in the ability to perceive sounds. In adults, hearing loss can be partial or total, sudden or gradual, temporary or permanent. It can affect one ear or both. Currently in the United States, 28 million people over age 3 have some form of hearing loss. The condition affects approximately 3% of all adult men and women. In general, the risk of hearing loss increases with age. Between 24% and 40% of adults over age 65 have difficulty hearing. Thirty percent of people over age 85 are deaf in at least one ear.

To understand hearing loss and treatment, it helps to know how hearing works. Sound enters the ear and strikes the eardrum (tympanic membrane). This causes the eardrum to vibrate. The eardrum's vibrations are amplified through the middle ear by three tiny bones. Inside the ear, the vibrations are transformed into nerve impulses. These nerve impulses travel to the brain, where they are interpreted as sounds.

Because the outer ear and middle ear transmit (or conduct) sound, any injury to this part of the hearing pathway is called conductive hearing loss. Sensorineural hearing loss is injury to the inner ear, eighth cranial nerve and brain, which all deal with the production, transmission and interpretation of nerve impulses.

In adults, some of the most important causes of hearing loss are:

• Middle ear disease – A bacterial infection of the middle ear can injure the eardrum, disrupt the middle-ear bones, or cause fluid buildup.



• Noise – Without adequate ear protection (earmuffs or earplugs), loud sounds can injure delicate cells within the ear. This is a form of sensorineural hearing loss, and it is the most common cause of hearing loss among American adults. Noise-induced hearing loss can happen because of a single brief burst of an extremely loud sound, such as a gunshot or firecracker. It is more often the result of long-term exposure to loud sounds of slightly lower intensity, such as factory noise or rock music. Among U.S. workers, noise-induced hearing loss is the most common of all occupational injuries. It is a significant health problem among carpenters, miners, plumbers, factory workers, farmers, construction workers and workers exposed to aircraft, sirens or explosives. People can also develop noise-induced hearing loss from recreational activities, such as listening to very loud music, operating a personal watercraft (such as Jet Ski and WaveRunner) or snowmobile, shooting firecrackers or guns, or operating a loud lawnmower or leaf blower.



• Otosclerosis – This conductive hearing loss involves the abnormal overgrowth of one or more bones in the middle ear. It prevents the small bones from moving normally. Otosclerosis often runs in families. It strikes 1% of American adults, and is especially common among white, middle-aged women.



• Acoustic neuroma – This noncancerous (benign) tumor grows on part of the eighth cranial nerve, which carries signals to the brain. Because this tumor develops near parts of the body that help control balance as well as hearing, it often causes dizziness and equilibrium problems in addition to gradual hearing loss. Acoustic neuromas most often occur in adults between the ages of 30 and 60.



• Mıniıre's disease – This typically causes dizziness, hearing loss, ringing in the ears (tinnitus) and a sensation of fullness or stuffiness in one or both ears. Although research suggests that M�ni�re's disease is related to a change in the volume of a fluid inside the ear, the reason for this volume change remains unknown. M�ni�re's disease currently affects three to five million Americans.



• Trauma – Many types of accidents can cause hearing loss, including stab wounds, gunshots or being hit on the ear or skull. Hearing loss can come from a blast injury to the eardrum from the force of an explosion or simply from a cotton swab (Q-tip) that ruptures the eardrum during an attempt to clean the ear canal.



• Sudden sensorineural hearing loss – This is a medical emergency. A person loses hearing over a period of three days or less. In 85% to 90% of cases, the cause is unknown, although many doctors believe that the underlying problem may be a viral infection. Doctors diagnose about 4,000 Americans with this type of heearing loss each year. In 90% of the cases, only one ear is affected.



• Drugs – Many prescription and nonprescription medications can damage the ear and cause hearing loss. These include:
  
  
  • Antibiotics, such as erythromycin (several brand names), vancomycin (Vancocin), tetracycline (several brand names) and aminoglycosides, such as gentamicin (several brand names), streptomycin (Zanosar), tobramycin (Nebcin) and amikacin (Amikin)
  • Anticancer chemotherapeutic drugs, such as cisplatin (Platinol), 5-fluorouracil (Ancobon) and bleomycin (Blenoxane)
  • Aspirin
  • Antimalaria drugs


• Age – Age-related hearing loss, also known as presbycusis, is not a single disease, but a category for the cumulative effects of aging on the ears. In most cases, hearing loss begins after age 60, and is usually more noticeable in men than women. Both ears are affected. It is typically harder to hear high-pitched tones (women's voices, violins) than low-pitched ones (men's voices, bass guitar). Because this usually occurs gradually over a period of years, the person may not realize that he or she has difficulty hearing. A family member may bring the problem to the person's attention.



• Other causes – There are more than 100 different causes of hearing loss in adults. The most common reversible cause is severe buildup of earwax in the ear canal and acute infections of the external ear or middle ear.

If you have sudden, severe hearing loss, you will notice right away that your ability to hear has decreased dramatically or disappeared totally in the affected ear. For example, you may snap your fingers next to the affected ear and not hear it, or you may put the telephone receiver against your ear and hear nothing.

If your hearing loss is gradual, your symptoms may be more subtle. You may have difficulty understanding conversations, either in person or over the telephone. Family members may complain that you play the radio or TV too loudly. You may ask them to repeat what they say or frequently misunderstand what they are saying.

Some diseases and conditions that cause hearing loss may produce additional symptoms, including:

• Ringing in the ears (tinnitus)
• Discharge or bleeding from the ear
• Deep earache, or pain in the ear canal
• Pressure or a "stuffy" feeling inside the ears
• Dizziness or problems with balance or equilibrium
• Nausea

After you describe your symptoms, the doctor will ask if anyone in your family has had (or has) hearing loss. Your doctor will want to know if you have been exposed to loud noises, trauma of the ear or head, or ear infections. To rule out the possibility that medications may be the cause of your hearing loss, your doctor will review the prescription and over-the-counter drugs you take.

Your doctor will examine you, and look closely at your ears. This ear exam may include:

• An examination of your ear canal and eardrum using a lighted instrument for looking inside the ears (otoscope)
• The Rinne test, in which a vibrating tuning fork is placed on the bone behind your ear to test for conductive hearing loss
• The Weber test, in which a vibrating tuning fork is placed in the middle of your forehead to help diagnose one-sided hearing loss
• Audioscopy testing, in which the doctor uses a hand-held device to generate tones of various intensities to find out if you can hear them

If the results of your ear exam suggest that you have hearing loss, your doctor will refer you to an audiologist. The audiologist will test your hearing sensitivity (with audiometry) and check for middle-ear problems by measuring your eardrum's ability to reflect sounds (impedance testing). Further testing and treatment will follow.

The duration of hearing loss depends on its cause. In general, sensorineural hearing loss tends to be permanent.

You can help prevent hearing loss by taking the following steps:

• Wear protective earplugs or earmuffs if you are often exposed to loud noise at work or during recreational activities. To help protect workers, the U.S. Department of Labor's Occupational Safety and Health Administration (OSHA) has developed regulations governing noise exposure on the job.
• Never put cotton swabs or other foreign objects in your ears.
• Wear a seatbelt while driving, and wear a protective helmet while riding a bicycle.
• Be informed about the possible side effects of your prescription and nonprescription medications.

Both age-related and noise-related hearing loss tend to be permanent. However, depending on the severity of your hearing loss, your doctor may recommend either a hearing aid or an implant to improve your ability to communicate with others. A hearing aid amplifies sounds electronically and is effective for many people with age-related hearing loss. Newer digital technology has produced smaller and more powerful devices. A cochlear implant is a device that translates sounds into electrical signals that can be carried by the eighth cranial nerve to the brain.

Certain other forms of hearing loss may be treated medically or surgically:

• Otosclerosis – For mild cases, a hearing aid is usually the first option. In severe cases, one of the small bones is surgically replaced with a tiny piston-like prosthesis.



• Acoustic neuroma – Treatment includes surgery or highly focused radiation therapy.



• M�ni�re's disease – There is no cure. Some people with this disease improve with a personalized diet plan (such as limiting intake of salt, caffeine or alcohol), quitting smoking, or medications to reduce fluid retention in the ear. In some cases, surgery may be considered.



• Traumatic hearing loss – A damaged eardrum can sometimes be repaired surgically by using tough, fibrous connective tissue (muscle fascia).



• Drug-induced hearing loss – Stopping the problem medication may reverse hearing loss or prevent it from getting worse.



• Sudden sensorineural hearing loss – In most cases, when the cause is unknown, this condition is treated with steroids.



• Other – A dense plug of earwax can be dissolved or gently removed from your ear canal by your doctor; also, antibiotics can treat hearing loss caused by ear infections.

Call your doctor immediately if you have sudden hearing loss. This is a medical emergency.

Also, make an appointment to see your doctor if:

• You are an older adult, and hearing loss interferes with your quality of life.
• You work in a high-noise environment, and you have trouble hearing.
• You have hearing loss together with an earache, a discharge from your ears, tinnitus, dizziness or balance problems.

The prognosis is highly variable. However, even if your hearing loss cannot be treated with medications or surgery, your quality of life may improve significantly with a hearing aid. In some people who do not improve with a hearing aid, a cochlear implant may be an option.

National Institute on Deafness and Other Communication Disorders
National Institutes of Health
31 Center Drive, MSC 2320
Bethesda, MD 20892-2320
Phone: 301-496-7243
Toll-Free: 1-800-241-1044
Fax: 301-402-0018
TTY: 1-800-241-1055
Email: nidcdinfo@nidcd.nih.gov
http://www.nidcd.nih.gov/

American Academy of Otolaryngology – Head and Neck Surgery
One Prince St.
Alexandria, VA 22314-3357
Phone: 703-836-4444
Email: info@entnet.org
http://www.entnet.org/

American Speech-Language-Hearing Association (ASHA)
10801 Rockville Pike
Rockville, MD 20852
Toll-Free: 1-800-638-8225
TTY: 1-800-638-8225
Fax: 301-571-0457
TTY: 301-897-0157
Email: actioncenter@asha.org
http://www.asha.org/

National Institute for Occupational Safety and Health
4676 Columbia Parkway
Mail Stop C-18
Cincinnati, OH 45226
Toll-Free: 1-800-356-4674
Fax: 513-533-8573
http://www.cdc.gov/niosh/

American Tinnitus Association
P.O. Box 5
Portland, OR 97207-0005
Phone: 503-248-9985
Toll-Free: 1-800-634-8978
Fax: 503-248-0024
Email: tinnitus@ata.org
http://www.ata.org/