By age 75, 35 percent of people have age-related hearing loss, which first affects highest-pitched sounds. Such hearing loss is driven largely by genetics, with some people hearing with batlike precision well into their 90s, while others lose the ability to hear a whispered "I love you" in their 60s.
In December, researchers identified a gene that may be to blame. It helps regulate glutamate, which is an essential neurotransmitter in the ear but can also kill off sensory cells and neurons if there's too much. "Genetically sensitive people may have more glutamate around their whole lives, and in the mid-to-late 50s, they start losing hearing in the high to middle registers," says Rick Friedman, a neurotologist at the House Ear Clinic in Los Angeles who led the genome study. If this proves to be true, Friedman says, doctors might someday treat the genetically susceptible with a drug.
In the meantime, it's relatively simple to reduce the risk of the other big culprit in hearing loss: noise. Excessive noise exposure permanently damages the inner ear's hair cells, which transmit sounds toward the brain. The damage is cumulative; more AC/DC concerts, more hearing loss. Tinnitus, or ringing in the ears, is a sign that the hair cells are getting fried. So is muffled hearing immediately after being exposed to loud noise.
"I wear ear protection when I do my lawn," says Barry Hirsch, director of neurotology at the University of Pittsburgh Medical Center and chairman of the hearing committee for the American Academy of Otolaryngology-Head and Neck Surgery. His sons, ages 18 and 20, do too. That's good, because a power lawn mower easily cranks out 90 decibels of noise; long-term exposure to levels above 85 decibels can cause permanent damage, according to the National Institute for Occupational Safety and Health.
Hearing protection needn't be dorky; small foam earplugs, when rolled tightly and inserted snugly, can provide 15 to 20 decibels of protection. Forget sticking cotton in your ears, Hirsch says; it doesn't work at all. Customized musician's earplugs, which lower sound exposure by about 25 decibels while perserving harmonic range, cost about $150. "I'm a rock-and-roll fan, and I always wear earplugs," says Friedman.
People needing more hearing protection (skeet shooters take note: A shotgun blasts out 165 decibels) can opt for earmuff-type protectors, which muffle up to 30 decibels. Earmuffs can be layered on foam plugs for added protection. (To determine the loudness, as measured in decibels, of sounds from a whisper to a rocket launch, check out NIOSH's interactive noise meter.)
A last caution: Some medications—including intravenous antibiotics, chemotherapy drugs, and narcotics such as hydrocodone—can permanently damage hearing. People who have lost hearing in one ear should be sure to let their doctor know, says Hirsch, so that they minimize risk to the remaining good ear.