Hearing Loss

According to the National Institute on Deafness and Other Communication Disorders (NIDCD), some 28 million Americans have a hearing impairment. Although we're more likely to experience problems with hearing as we get older, hearing loss cuts across all age groups too, affecting approximately 17 in 1,000 children under age 18.

Hearing loss can vary from a loss of sensitivity to certain sounds, to a total loss of hearing. Hearing loss can also be accompanied by other problems. In addition, some types of hearing loss can be corrected, and some cannot.

Hearing depends on a complex series of events. First, sound enters the ear, which consists of three major parts: the outer ear, middle ear and inner ear. (Read about "The Ear and Hearing") Sound waves enter the outer ear and travel through the ear canal to the eardrum. The eardrum vibrates from the incoming sound waves and transmits these vibrations through three tiny bones called the ossicles (the malleus, incus and stapes) in the middle ear. These tiny bones amplify the sound and send it to the inner ear and into the fluid-filled hearing organ called the cochlea. Here, the vibrations create ripples in the fluid that bend projections from tiny hair cells in the cochlea, causing electrical impulses that the auditory nerve or eighth cranial nerve, sends to the brain. (Read about "The Brain" "Nervous System") The brain then translates these impulses into what we experience as sound. But sometimes, there can be a problem.

Possible causes

There are many conditions that can lead to hearing impairment, including but not limited to:

• Birth defects - Hearing loss is one of the most common birth defects, according to the March of Dimes (MOD). Newborns are often screened for hearing loss. (Read about "Newborn Screenings") Genetic factors (Read about "Genetics") are believed to cause about 50 percent of cases of congenital hearing loss. About 30 percent of children with hearing loss also have other birth defects. Illnesses during pregnancy can cause congenital hearing loss. They include infections during pregnancy, such as rubella, cytomegalovirus, toxoplasmosis, herpes or syphilis. (Read about "Childhood Illnesses" "Herpes" "Toxoplasmosis" "STD's") Babies born preterm (Read about "Preterm Labor") also are at increased risk. (Read about "Birth Defects")
• Presbycusis - Presbycusis is the name given to age-related hearing loss, and it is not uncommon. NIDCD says that about 30-35 percent of adults between the ages of 65 and 75 years, and up to 50 percent of people 75 and older, have a hearing loss. NIDCD says high-pitched sounds are the ones most commonly affected. For example, someone might not be able to hear the sound of their phone, even though they can hear lower pitched noises such as traffic. A common complaint is the inability to pick out an individual voice in a crowded room. The condition can result from changes in the inner ear, the outer ear or the nerve. The changes can be cause by a number of things, including heredity, repeated exposure to loud noise or certain medications. (Read about "Family Health History" "Noise and Hearing" "Medicine Safety") Other factors that can contribute to presbycusis include changes in the blood supply to the ear resulting from heart disease, high blood pressure, vascular problems or diabetes (Read about "Coronary Heart Disease" "Hypertension: High Blood Pressure" "Diabetes") The degree of hearing loss may be mild, moderate or severe. Often, NIDCD says both ears are affected, but the change is so gradual that many people may not realize it is happening.
• Otosclerosis - Otosclerosis is the abnormal growth of bone of the middle ear. This leads to hearing loss, which can be severe for some people. NIDCD says we're not sure what causes otosclerosis, although it may be hereditary. (Read about "Family Health History") The most common symptom of otosclerosis is hearing loss. It may appear very gradually, with many people first noticing that they cannot hear low-pitched sounds or that they can no longer hear a whisper. In addition to hearing loss, some people with otosclerosis may experience dizziness or balance problems. (Read about "Balance Disorders") Tinnitus, or a ringing in the ears, may also be present. (Read about "Tinnitus") Surgery will sometimes be recommended as the best option, and some cases can be helped with use of a hearing aid.
• Diseases - Diseases that impact balance, such as Meniere's disease and acoustic neuroma, also cause hearing loss. (Read about "Balance Disorders") Diseases such as cancer or stroke can affect hearing as well. (Read about "Head and Neck Cancers" "Stroke") Infectious diseases - including measles, mumps and meningitis - can also affect hearing. (Read about "Childhood Illnesses" "Encephalitis and Meningitis")
• Trauma - Head injury can lead to hearing loss. (Read about "Head Injury")
• Noise - Exposure to loud noise can impact our hearing. (Read about "Noise and Hearing")
• Medications - Certain medications are considered ototoxic, that is damaging to the ear. These include certain antibiotics, as well as high doses of aspirin. (Read about "Aspirin and Heart" "Antibiotics" "Medicine Safety")
• Otitis externa - Commonly referred to as swimmer's ear, it stems from an infection of the ear canal. (Read about "Otitis Externa")
• Otitis media - Fluid or infection in the middle ear can impact hearing. (Read about "Otitis Media")
• Ruptured eardrum - A ruptured eardrum can lead to sudden pain as well as hearing problems. (Read about "Ruptured Eardrum")
• Ear wax - A buildup of too much ear wax can affect hearing, and lead to earache. (Read about "Earache")

Hearing loss can vary from a mild but important loss of sensitivity, to a total loss of hearing. Hearing loss can also be accompanied by other problems, such as ringing in the ears, a condition called tinnitus. (Read about "Tinnitus") In addition, some types of hearing loss can be corrected, and some cannot. The important thing is that, if you have trouble hearing, you should visit your doctor or hearing healthcare professional to find out if you have a hearing loss and, if so, how to treat it.

If you suspect hearing loss in yourself or your child, your healthcare professional may recommend a hearing test. The Food and Drug Administration (FDA) says you may be referred to either an otolaryngologist or an audiologist. An otolaryngologist is a physician who specializes in ear, nose and throat disorders, and will investigate the cause of the hearing loss. Audiologists are usually not medical doctors but are trained to give hearing tests and interpret the results.

Options

If there is a loss of hearing, and it can be corrected, treatment depends on the cause. The cause and treatment might be simple. For example, for hearing loss that results from ear wax buildup, the ear may be flushed. Other conditions may require a combination of medication and/or surgery. For example, antibiotics may be prescribed if a bacterial infection (Read about "Microorganisms") is causing the hearing loss. In otosclerosis, surgery may be needed to remove the excess bone growth.

Some types of hearing loss cannot be corrected. Sensorineural hearing loss is hearing loss due to problems of the inner ear and/or auditory nerve. Sensorineural hearing loss is not considered reversible.

There are also many strategies to help people with hearing loss and deafness. These include:

• American Sign Language (ASL) - ASL is a complete, complex language that employs signs made with the hands and other movements, including facial expressions and postures of the body.
• Captioning - Captions are words displayed on a television screen that describe the audio or sound portion of a program.
• Cochlear implant - A cochlear implant is a small, complex electronic device that can help to provide a sense of sound to a person who is profoundly deaf or severely hard-of-hearing.
• Assistive listening devices - This includes devices such as telephone amplifiers
• Speech reading - Training in speech reading (using visual cues to determine what is being spoken) can help those with presbycusis to understand better what is being said in conversations or presentations.
• Hearing aids - Hearing aids can usually help hearing loss that involves damage to the inner ear. This type of hearing loss is common in older people as part of the aging process. But younger people can also have it from infections or repeated exposure to loud noises.

Some people only need a hearing aid for one ear. Other people need one for each ear. Depending on the degree of hearing loss, there are hearing aids that can be worn behind the ear, in the ear, in the ear canal or on the body. There is also a device that is implanted behind the ear during surgery, called a cochlear implant. FDA says this is only used for very bad hearing loss. Hearing aids consist of:

• a microphone, to pick up sound
• an amplifier, to make sound louder
• a speaker, to bring sound to the ear
• a battery

NIDCD says adjusting to a hearing aid is a gradual process that involves learning to listen in a variety of environments and becoming accustomed to hearing different sounds.