One in four people aged 65 to 74—and half of those 75 and older—have some degree of hearing loss. Yet less than one in five adults who need hearing aids actually wear them. That may soon change. On October 17, it became legal to sell hearing aids without a prescription.

Here’s what to know about hearing loss, hearing aids, and what may protect your hearing.

Hearing loss 101

Why does hearing decline as you age? Aging takes a toll on the inner ear.

“Most cells in your body are constantly regenerating,” says Nicholas Reed, director of the audiology core at the Cochlear Center for Hearing and Public Health at the Johns Hopkins Bloomberg School of Public Health.

“You cut your skin and it grows back. But the hair cells in the cochlea—the part of the inner ear that encodes sound—don’t regenerate.”

The middle ear includes the eardrum and the malleus, incus, and stapes, the smallest bones in the body. Their job is to transmit sound waves to the hair cells. 

“When the hair cells are triggered by sound, they transmit a signal along the auditory nerve, which sends a signal to the brain,” explains Reed, who also serves on the advisory board of Neosensory, a company that sells vibrating wristbands to improve hearing.

Over time, those hair cells deteriorate.

“There’s cumulative damage from loud music, smoking, and high blood pressure and other cardiovascular problems,” notes Reed.

“They may not cause heavy hearing loss themselves, but stacked together, those and other insults eventually result in hearing loss.”

And damaged hair cells explains why people lose clarity, though not the ability to detect loudness.

“The hair cells are organized like a piano, from high to low frequency,” says Reed. “Sound moves the hair cells in that order.”

It’s the loss of high frequency sounds that diminishes clarity.

“Low frequency sounds are vowels and nasal sounds,” says Reed. “They provide the base foundation of words, whereas the clarity and meaning of words often come from high frequency consonants—the ‘th,’ ‘s,’ ‘f’ sounds.”

(Those sounds are made by the friction of your breath passing through the narrow opening of your mouth when you pronounce those letters.)

“When you lose the ability to hear high frequency sounds, it’s not that you can’t hear someone talking to you,” says Reed. “You just can’t make out what they’re saying.”

Or maybe you can figure it out, but it takes extra effort.

“Sometimes, it’s possible to overcome that clarity issue if you think about the context of the conversation,” says Reed. “It’s like listening to a bad cellphone signal.”

And although hearing aids can help, they’re not a perfect fix, like wearing glasses to correct near- or farsightedness.

“For most vision loss, glasses are corrective,” says Reed. “They correct the refractive error, so you can get back to normal vision or close to it. It’s a mechanical problem. We’re just refocusing the lens.”

In contrast, hearing loss is a sensory problem.

“With hearing aids, you’re still listening with that cellular damage in the ear,” notes Reed.

“We can make the sound louder and manipulate it to take advantage of hair cells that are still able to encode sound. Or we can try to pull sound signals apart from background noise or focus on one area of hearing, like what’s right in front of you versus what’s behind you.”

But hearing aids are still an imperfect fix. “We have no magic pill to cure hearing loss,” says Reed.

It’s not just hearing

Treating hearing loss may do more than make it easier to have conversations, watch movies or TV, and listen to music. The biggest question: Could hearing aids keep your mind sharp as you age?

People with hearing loss are more likely to have cognitive decline. But that’s not proof that curbing hearing loss slows memory loss.

“A common cause—like inflammation or microvascular disease—could lead to both hearing loss and cognitive decline,” says Jennifer Deal, assistant professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health.

To find out if hearing aids can slow cognitive decline, the ACHIEVE trial randomly assigned 977 people aged 70 to 84 with mild-to-moderate hearing loss to either a hearing intervention—including hearing aids and devices to stream phones and TV directly to hearing aids—or a health education control group for three years. Results are due in 2023.

“We’ll be able to follow them for an additional three years,” says Deal, “so if the effect is delayed, we’ll hopefully be able to pick that up.”

How might hearing loss harm the brain?

Cognitive load

Encoding sound into a neural signal in the inner ear is just the first step of hearing.

“The second step happens when that neural signal is sent to the brain, where it’s decoded,” explains Deal. “That’s how the brain understands the sounds you hear.”

“With hearing loss, instead of that sound being encoded into a crisp, clear signal, there’s poor encoding of that degraded sound, so the signal that goes to the brain is garbled.”

That means the brain has to work harder to decode the signal.

“The concern is, when you’re putting extra processing effort toward decoding the signal, you’re not doing things like forming memories.”

Direct harm to the brain

“When we put individuals in scanners to see what’s happening inside the brain, people who have hearing loss are recruiting different parts of their brain to decode the signal from the inner ear than others,” says Deal.

What’s more, she adds, “people with hearing loss have faster rates of atrophy—greater shrinkage—in the whole brain and in the temporal lobe.” That’s the part of the brain that decodes sound. 

“So hearing loss may directly impact what’s going on in the brain,” says Deal.

Social isolation

“Age-related hearing loss is a subtle, gradual process that many people don’t notice until they start having difficulty hearing in noisy environments, like crowded restaurants,” says Deal.

If that leads them to go out or talk with other people less often, it may shrink their social contacts, which is a risk factor for memory loss.

Better hearing may not only keep your mind sharp. It could also prevent falls.

“Hearing helps us understand where we are in our environment, and that can help us keep our balance,” says Deal.

For example, researchers had blindfolded people try to keep their balance with or without their hearing aids.    

“They were standing on a foam pad, so they couldn’t use their sense of touch to understand where they were,” says Deal.

“When asked, they felt like they had performed the same in both trials. But when you look at the data, people did better with their hearing aids on.”

Does hearing loss also boost the risk of anxiety or depression? In some studies, both are more common in people with untreated hearing loss. But that doesn’t prove that hearing loss is the trigger.

“We need more research in this area,” says Deal.

That said, how many reasons do you need to treat hearing loss?

“Even if hearing loss doesn’t make a difference for cognition or other outcomes, it certainly impacts your quality of life and communication with your loved ones,” says Deal.

Over-the-counter hearing aids

Hearing aids for adults with mild or moderate hearing loss can now be sold over the counter. What took so long?

“Traditionally, we had a gatekeeper model,” says Johns Hopkins’s Nicholas Reed. To get a hearing aid, you’d need a prescription from an audiologist or an ear, nose, and throat doctor.

“And they’d decide which hearing aid you should get,” notes Reed.

The cost would typically be bundled with charges for return visits to fit the device to match your hearing loss.

The average price tag—which is not covered by Medicare or most insurance—was $4,700 a pair, making hearing aids the third most expensive item that many households purchase (after a home and a car).

Over the years, the gatekeeper model stifled competition.

“Only five companies owned nearly the entire hearing aid market worldwide,” says Reed. “They owned every aspect of the distribution channel. They made the hearing aids, they employed the hearing aid dispensers, they owned the clinics and the marketing firms.”

The companies tried to kill the 2017 law that directed the FDA to create the category of over-the-counter hearing aids. Then they pressured the FDA to set limits to make the OTC devices only suitable for mild hearing loss. But the FDA didn’t cave.

“Forty years ago, the gatekeeper model made sense because there was no way that a regular person could just walk off the street and fit their own hearing aid,” says Reed. “But hearing aids went digital in the early 2000s, and now you can use your smartphone to self-fit one.”

Bringing new companies into the market should shake it up.

“We’re in totally new territory now,” says Reed. “OTC hearing aids are going to change affordability and that’s going to increase accessibility.”

In fact, the FDA allowed a handful of companies—like Lexie and Lively—to sell hearing aids “direct to consumer” before mid-October, and they cost between $800 and $2,000. (Those devices have until April 14 to meet the FDA’s new OTC standards.)

“And I’m downright giddy over where the technology could go,” says Reed. It’s already starting.

“In anticipation of over-the-counter sales, companies are focusing on using smartphone processors. They’re more powerful than the processors in current hearing aids, and they can do things in the cloud. Others are thinking about using artificial intelligence algorithms for speech detection.”

Unfortunately, it’s too early for Reed to zero in on your best bet.

“Everybody wants me to rank the top 10 OTC hearing aids,” he says. “We’re not there yet.”

And going the OTC route isn’t for everyone. Some things to consider:

OTC or prescription? 

OTC hearing aids are for adults with mild or moderate—not severe—hearing loss.

“If you’re in that gray zone between moderate and severe, you might want to look at both OTC and prescription hearing aids,” says Reed.

To save money on an audiologist, he adds, try Costco. “They sell the same hearing aids as some audiologists. The Kirkland brand is made by Sonova, one of the biggest manufacturers of hearing aids in the world.”

Do-it-yourselfer?

“If you go the full OTC route, you’ll have to spend time reading the instruction manual,” says Reed. “If you’d rather set it and forget it, then maybe you want the prescription route. Or you can get an OTC hearing aid and take it to a professional for fitting. Think of them as mechanics, not as car salesmen.”

Company backing?

“You should see a warranty and a return period in case you want your money back,” says Reed. “And make sure there’s a robust support system, like a customer service number.”

Adjustable?

“Look for an app that lets you take a hearing test with the hearing aid and then fit it according to your needs instead of a device that’s pre-programmed,” says Reed.

If you search on Amazon, you may find “hearing aids” for $100. Odds are, they’re personal sound amplification products (PSAPs).

“Most amplifiers on the market are basically junk,” says Reed. “Years ago, our research showed that one of those off-the-shelf $30 amplifiers would have made it harder for people to hear.”

A good hearing aid should only amplify the sounds that you can’t hear.

“Most hearing aids amplify high frequencies and offer customized output,” says Reed. “But most amplifiers aren’t designed for hearing loss. If they amplify both high and low frequencies, that makes it harder to hear.”

What’s more, the FDA’s new standards don’t apply to PSAPs, so the devices are still a crapshoot.

“Some of the good PSAPs might jump over to the OTC hearing aid side,” Reed speculates. “But now I’d just get an OTC hearing aid so you have the peace of mind of knowing that whatever you’re buying is good.”

Should you buy now or wait? 

“The market is in a wait-and-see-what-shakes-up phase,” says Reed. “Once we have products on the market, it might be easier to say a Lexie Lumen does ABC, while the Braun Clear does XYZ. I’m waiting to see what big manufacturers like Samsung or Apple do. It’s super exciting.” 

Just don’t wait too long.

“The longer you wait, the harder it is to adapt to hearing aids later,” cautions Reed. “Some people come into my office and say, ‘I only have one problem. It’s just talking to my granddaughter, or it’s just one weekly meeting at work.’” 

“But if you let that one thing go, over time, you’re losing other sounds. And you may not notice because our brains are good at ignoring things.”

So by the time you buy a hearing aid, you’ll need a bigger adjustment.

“It’s harder to adapt if you’ve been living in silence for longer,” says Reed. “In the long run, you’ll get used to hearing aids faster if you don’t wait.”