Elizabeth A. Reid, MD Do You Hear What I Hear? G
RADUAL LOSS OF hearing in older adults is often accompanied
by denial. “It’s not my hearing— other people are mumbling.” “I’m not hard of hearing; it’s just too noisy in here.” The phrase “hard of hearing” often conjures up vi- sions of elderly relatives strug- gling to adjust squealing plastic earpieces while missing out on most of the conversation around them. Losing one’s hearing can be the knockout blow to the illu- sion of perpetual youth. No won- der, then, many people seek help only when their closest relatives and friends force them to. Failing ears deserve treatment. As Helen Keller allegedly said, “Blindness separates us from things, but deafness separates us from people.” Separation from people precisely describes the ef- fect of hearing loss. Speech is the coin of human interaction, and even a partial loss of the ability
to hear and understand speech diminishes the quality of one’s life. Most often, higher fre- quency sounds disappear first— sounds like f, sh, ch, p, s, and t. Try dropping these letters out of the next sentence you say, and you’ll get an idea of what speech sounds like to someone with failing ears.
Age and Hearing Loss Age-related
hearing loss, called presbycusis, accounts for 10 Other Kinds of Hearing Loss
Hearing loss is not always a benign problem of aging. Signs that something else is amiss include a rash in or around the ear, the sudden onset of hearing loss, one-sided hearing loss, or loss accompanied by dizziness, imbalance, slurred speech, or pain in the ear. Prompt evaluation by an internist or otolaryn- gologist is appropriate. Deafness in children always warrants a medical evaluation.
90 percent of hearing problems and is a symptom of a slow de- cline in the sensory and neural components of the hearing sys- tem, which includes the fine hairs on inner ear sensory cells (the cells that convert mechanical sound waves to
electrical sig-
nals), the nerve fibers that trans- mit the electrical messages to the brain, the blood vessels that nourish the whole system, and the array of nerve cells in the brain devoted to decoding sound. Why do some people experi- ence hearing loss as they age while others don’t? Several hun- dred genes are known to be in- volved in hereditary deafness, and it is likely that variations in some of these genes contribute to the “aging” of the anatomically and physiologically complex au- ditory system. Environmental fac- tors accelerate the decline. Even the hearing of genetically robust ears is affected by long years of chronic exposure to loud noise, by smoking, and by many drugs
in common use, including amino- glycoside antibiotics, aspirin, many analgesics, cardiac medi- cines, and mood-altering drugs. Hearing damage caused by drugs is probably underreported and in- creasing. Unfortunately, only an estimated 20 percent of those who experience hearing loss seek help. Only about 30 percent of those over the age of sixty-five and 40 to 50 percent of those over the age of seventy-five who have enough hearing loss to in- terfere with communication ever seek help with their hearing.
Getting Help The first step to better hearing
is an evaluation by a physician. Routine physical exams should include simple hearing tests. Sus- pected presbycusis should prompt an evaluation by a com- petent audiologist. (Certain types of hearing loss require further medical evaluation—see sidebar.) The audiologist’s testing gener- ates a graph of the level of sound
required for a patient to hear a spectrum of frequencies, and this audiogram is the basis for pro- gramming a hearing aid. Hearing aids work by boosting the volume of sound reaching intact portions of a declining au- ditory system. Each hearing aid is like a miniature sound system. A tiny microphone picks up sound, while an amplifier boosts its volume, and a speaker car- ries the amplified sound to the remaining functional hearing cells, which then pass the information over nerve fibers to the brain. Tiny batteries power the system. Modern hearing aids transform sound waves into simple, digital binary code. They offer options for selecting only the sound fre- quencies that need to be boosted, which helps reduce annoying background noise. The most helpful option may be the addi- tion of directional microphones, which focus sound in conversa- tional settings. Many hearing aids also incorporate noise cancella- tion systems such as those that eliminate screechy feedback from landline phones. (This feature only works with hearing aid–com- patible phones, and unfortunately, most cell phones do not yet work with this feature.) Most recently, wireless technology enables the transmission of sounds from de- vices like iPods and mobile phones directly to a hearing aid. (Continued on page 56)
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