What Is It?

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, and it can affect one ear or both. Currently in the United States, 28 million people over age 3 have some form of hearing loss. During adulthood, the condition affects approximately 3 percent of all men and women. In general, the risk of hearing loss increases with age. Between 24 percent and 40 percent 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), causing the eardrum to vibrate. The eardrum’s vibrations are amplified through the chamber of the middle ear along three tiny interconnected bones. Inside the ear, the energy produced by the vibrations is 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. The inner ear, eighth cranial nerve and brain deal with the production, transmission and interpretation of nerve impulses. An injury to this part of the hearing pathway is called sensorineural hearing loss.

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 currently the most common cause of hearing loss among American adults. Noise-induced hearing loss sometimes happens because of a single brief burst of an extremely loud sound (gunshot, 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 (one brand is Jet Ski) or snowmobile, shooting firecrackers or guns, or operating a loud lawnmower or leaf blower.



• Otosclerosis — This is a conductive hearing loss, involving 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, strikes 1 percent of American adults, and is especially common among white, middle-aged women.



• Acoustic neuroma — This benign (noncancerous) tumor grows on a part of the eighth cranial nerve, which carries signals to the brain. Since this tumor develops near structures 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.



• Ménière’s disease — This typically causes vertigo, hearing loss, ringing in the ears (tinnitus) and a sensation of fullness in one or both ears. Although research suggests that Ménière’s disease is related to a change in the volume of a fluid inside the ear, the reason for this volume change remains unknown. Ménière’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; blast injury to the eardrum from the force of an explosion; or simply 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 in which a person abruptly loses hearing over a period of three days or less. In 85 percent to 90 percent of cases, the cause is unknown, although many doctors believe that the underlying problem may be a viral infection. About 4,000 Americans are diagnosed with sudden sensorineural hearing loss each year. In 90 percent 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 the aminoglycosides — 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 catchall 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 — In total, 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, such as difficulty understanding conversations, either in person or over the telephone. Family members may complain that you play the radio or TV too loudly, 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

Once you have described your symptoms, the doctor will ask if anyone in your family has had (or has) hearing loss. Your doctor will also 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 also review the prescription and nonprescription drugs you take.

Your doctor will then conduct a physical exam, and look closely at your ears. This ear exam may include:

• An examination of your ear canal and eardrum using an otoscope (a lighted instrument for looking inside the ears)
• 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 (available in some doctors’ offices) 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 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.

Not all forms of hearing loss are reversible. For example, both age-related and noise-related hearing loss tend to be permanent and irreversible. 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.



• Ménière’s disease — Treatment may include a modified diet (low salt, no caffeine or alcohol), medications to reduce fluid retention or increase circulation in the ear, or surgery.



• 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 offending 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 due to 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.

In most cases, the prognosis is good. If your hearing loss cannot be treated with medications or surgery, your doctor may recommend a hearing aid. Surgical repair and cochlear implants may dramatically improve hearing in some people.

Medical Encyclopedia

All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.