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Hearing loss is not a universal aspect of aging, but it is very common among older adults and increases with age. Ten percent of adults 65—75 years old, and 25% of adults older than 75 years have hearing loss. Many people wrongly assume that hearing loss is only an inconvenience. Hearing loss can have profound effects on quality of life and lead to family friction, social isolation, loss of self-esteem, anger, and depression. Even mild hearing loss can lead to difficulty communicating, especially in noisy social situations, such as parties or restaurants. Research suggests that there is a link between hearing loss and mental difficulties, and between hearing loss and reduced ability to move around. Hearing loss can also affect the interaction between you and your health care provider, making communication more difficult and possibly jeopardizing your overall health. Treatment of hearing loss and attention to communication strategies can improve quality of life and relationships with family, friends, and caregivers.
How Normal Hearing Works Normal hearing depends on the functioning of the ear, the nerves, and the brain (Figure: The Ear). Sound vibrations enter the outer ear and vibrate the eardrum, which in turn vibrates a series of very small bones in the middle ear. These vibrations are translated into nervous impulses through special sensory cells. These impulses travel through the auditory (acoustic) nerve to the brain, where they are interpreted. The ear modifies the sense of sound, while the brain helps us perceive and interpret sound. Sound is characterized by frequency (pitch), which is measured in cycles per second, and by intensity (loudness), which is measured in decibels. In young people, the frequency range of normal hearing runs from about 30 cycles per second to 20,000 cycles per second. In older people, the range is from about 250 to 8,000 cycles per second. Normal speech is in a frequency range of 500 to 2,000 cycles per second. The intensity at which a sound must be generated to be heard by a person is termed that person’s threshold; the higher the threshold, the poorer the hearing. Causes of Hearing Loss Classic hearing loss in older adults has a characteristic pattern:
Common age-related changes that lead to hearing loss include a thickening of the eardrum, hardening of other auditory structures, loss of sensory cells, and decreased nerve function. Changes in memory and overall slowing of mental processes may also affect hearing and our ability to understand speech. Hearing loss can also be caused by disease processes involving the outer ear canal, the middle ear, the inner ear, the auditory nerve, the brain, or a combination of these. Disease processes involving the ear can result in conductive hearing loss. Those involving the nerves or brain can result in sensori-neural hearing loss, and those involving the brain can result in central hearing loss. Damage affecting more than one area is termed "mixed" hearing loss. Conductive hearing loss Earwax is a common cause of conductive hearing loss that reduces sound intensity. As we age, earwax becomes thicker and drier, clogging the ear canal and blocking sound from entering. This important and easily correctable cause of hearing loss affects about a third of older adults. Objects placed in the ear, ie, "foreign bodies," can also cause conductive hearing loss through a similar process. Most other causes of conductive hearing loss are not very common in older adults. These include severe infections in the ear canal, fluid in the middle ear, arthritis affecting the bones of the ear, or a hole in the ear drum. Paget’s disease of bone, which may affect the ear, is a cause of conductive hearing loss that is seen almost only in older adults (see Diseases of Hormones and Metabolism). Sensori-neural hearing loss Sensori-neural hearing loss is most often caused by damage (usually from noise) to the cochlea, which is a little spiral tube in the inner ear. Hearing loss is less common among people who live in quiet rural environments than among people who live in urban, industrialized communities. Other causes of sensori-neural hearing loss include certain medications (see below), genetics, blood vessel problems, and rarely occupational and environmental chemical exposures. Cigarette smoking may also cause sensori-neural hearing loss, and smokers have higher rates of hearing loss than nonsmokers. Certain autoimmune diseases or nerve tumors can also cause hearing loss on rare occasions. Some Drugs that may Cause Hearing Loss
In central auditory processing disorders, the loss of ability to understand speech is much more than would be expected based on the actual hearing loss. This is a problem in older adults and usually occurs only in people with dementia. It is rarely a problem in those with sensori-neural hearing loss. It is much harder to treat, and hearing aids are usually of less benefit. Central hearing loss can also be caused by brain tumors or hemorrhage. Evaluation of Hearing Loss The evaluation of hearing loss begins with telling your healthcare provider about difficulties related to hearing. Remember that hearing loss is not a normal part of getting older, and there is no reason to feel embarrassed. Recognizing and addressing the problem early can avoid many of the psychological problems associated with hearing loss. Because hearing loss tends to progress slowly, you may not even recognize that you have a hearing problem. It is helpful to have a family member or caregiver also report on your hearing and whether you seem to have hearing difficulty (eg, play the television or radio too loud). Healthcare providers often screen older adults for unrecognized hearing loss by asking standardized questions to see if you have difficulty communicating in various situations (eg, at a party). Your ear canal will be examined to look for wax, foreign material, inflammation, or other causes of conductive hearing loss. Wax and other debris should be removed before further testing. Most hearing problems require referral to an audiologist for "pure-tone audiometry," which is the basic test of hearing. During pure-tone audiometry, you’ll wear earphones and listen to pure tones at different pitches and volumes. These tones might be played to both ears or to either ear by itself. The audiologist will also test your ability to understand speech and for fluid or pressure in the middle ear. Audiometry testing can define how much hearing has been lost and determine the location of the problem. It can also give clues for the cause of the hearing loss. Treatment Some causes of hearing loss can be treated medically or surgically. However, most hearing loss in older adults is treated with strategies to improve communication, amplify the sound (eg, hearing aids), or both. Strategies to improve communication People with hearing loss should be encouraged to let others know about their hearing loss and to volunteer strategies that will help them communicate more easily. Many people use some form of lipreading while listening. This requires thoughtfulness on the part of the speaker, and proper vision and lighting to help the listener. Strategies to Improve Communication with People Who Have Hearing Loss
Be alert to the potential for misunderstanding when speaking to a person with hearing loss. If a reply does not make sense, try repeating what was said, using different words. It’s also helpful to ask the person to repeat what he or she heard to make sure there have been no misunderstandings. Writing words down also helps. Printing in large letters with a marker pen may be necessary, because many older adults also have vision problems (see Vision Loss). Hearing aids Hearing aids amplify sound. While not everyone with hearing loss benefits from a hearing aid, the appropriate hearing aid can improve the ability to communicate for most older adults, even those with severe sensori-neural hearing loss. Hearing aids often improve ability to understand speech, particularly soft speech and conversational loud speech. In general, hearing aids should be worn in both ears to preserve the directional clues that help to localize sound. All hearing aids should be purchased on a 30-day trial basis, so that they can be returned if they do not work out. However, you shouldn’t give up on a hearing aid too soon, because an audiologist can often adjust it to improve comfort and sound quality. It is best to purchase hearing aids from a comprehensive hearing-aid center that employs a registered audiologist. These centers generally provide good service and rehabilitation programs. Immediately after purchasing a hearing aid, you should begin a hearing rehabilitation program. This includes counseling regarding the benefits and limitations of hearing aids and suggestions for communicating with others. This counseling is part of the purchase price of the hearing aid and is done by the audiologist, who can also adjust the volume of the aid to help at the frequencies that match an individual’s pattern of loss. Of course, a hearing aid can’t help if you don’t use it. Many older adults purchase hearing aids, but then don’t use them or use them only occasionally. Reasons people give for not using hearing aids include less ability to use their hands, noise (such as the amplification of background noise), and the belief that the aid is not needed. Another problem that limits the use of hearing aids is the cost, which can be significant. Analog hearing aids can run from $750 to around $1500, and digital hearing aids can run from around $1200 to $3000 for one with premium features (eg, block out background noise, feedback control). Assistive listening devices are another, generally less expensive, option. These devices can be useful in specific situations and include personal amplifiers, telephone amplifiers, and television listening devices. They run around $150—$200 each. Medicare and most private health insurance companies typically do not cover hearing aids or assistive listening devices. However, they may cover hearing evaluation or hearing aids in some circumstances. Medicaid may cover hearing aids, but the reimbursement usually does not cover the whole cost. Federal programs such as the Department of Veterans Affairs may pay for hearing aids, depending on the recipient’s eligibility for services. Choosing the hearing aid that is right for you Many different styles of hearing aids are available. The style that is best for any individual depends on the degree of hearing loss, desire for available features, and the individual’s motivation and ability to properly insert and use the hearing aid. The most popular hearing aids are the behind-the-ear and in-the-ear models. Behind-the-ear hearing aids hang behind the ear and are connected directly to an earmold. They are more conspicuous than in-the-ear models, but they are durable, easily adjusted, and easily repaired if needed. The earmold is custom made to fit each person’s ear. Some behind-the-ear aids can also be connected to other assistive-listening devices (eg, telephone or television amplifiers). In-the-ear hearing aids are custom fit to the user and smaller than behind-the-ear-models. They may improve hearing at higher frequencies because they transmit sound better. These tiny in-the-ear devices are less noticeable than behind-the-ear models, and many people think they would like them because they can’t be seen. However, they are very difficult to adjust and maintain because tiny particles of skin get into these devices, and they stop working. They may also produce more feedback. The choice of an analog or a digital hearing aid depends on the individual. Analog aids are less expensive than digital aids and may provide acceptable sound quality. However, digital aids are smaller and have better sound quality. In addition, the amplification can be customized to the needs of the user. Often, two or more programs are available within a single hearing aid. For example, one program may be most useful when there is background noise, while another works better in a quiet environment. Some of the newer hearing aids automatically adjust the volume to increase amplification of soft sounds, while avoiding uncomfortable loudness. Background noise is a significant problem for users of hearing aids. Traditional hearing aids amplify all sound, so that background noises (like papers rattling or water running) can be very distracting. Newer technologies make use of multiple microphones and digital signal processing to decrease background noise. This can significantly improve the ability to understand speech and increase satisfaction with the hearing aid. Assistive-listening devices In addition to hearing aids, other helpful assistive-listening devices are available. All of these devices rely on a microphone that is moved close to the sound source, which means that the sound is usually clearer with less background noise. For some people with hearing loss, a personal amplifier may be more useful than a hearing aid. These pocket-sized devices are considerably less expensive than hearing aids, can be used by different people, and are harder to misplace. The headphones used with these devices stay on the head better than earbuds and provide sound to both ears. Adaptive equipment is also available to help with using the telephone. Some state agencies provide amplified telephones, vibrating and flashing ringers, and text telephones at no cost to people who are deaf or hard-of-hearing. This equipment is also available from electronics and telephone equipment stores. Devices that plug in the wall and provide amplification are much better than amplified telephones that use only the power in the phone line for amplification. A telecoil is a specific type of induction coupling coil that can be built into a hearing aid. It detects the magnetic field produced by telephones that are compatible with hearing aids. The telecoil allows the user to listen on the telephone with less distraction from noise in the same room. It can also be used with many assistive-listening devices. Although it has drawbacks, the telecoil is a useful feature and can be added to many hearing aids at a relatively small cost. Many other assistive devices are also available for listening to television and radio. Closed-caption television is also widely available. Vibrating and flashing devices such as alarm clocks and timers, smoke alarms, doorbell alerts, and motion sensors are convenient and can improve the safety of people with hearing loss. These items can be purchased through state agencies for people with hearing loss, or from catalog retailers of assistive-listening devices. Cochlear implants A cochlear implant is an electronic device surgically implanted into the ear. This implant bypasses the physiology of the ear and transmits sensory impulses directly to the nerves. A headset worn behind the ear contains a microphone that picks up sound, codes it into electronic signals, and transmits those signals to the implant. Having a cochlear implant surgery requires participation in extensive testing before surgery and training after surgery. The procedure is covered by most Medicare carriers and insurance companies. Cochlear implants are used only in people who have profound hearing loss for which hearing aids are of little or no benefit. While they provide only a basic level of hearing, this can have major benefits for people with profound hearing loss. |
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Published: 3/15/2005