Most of us have experienced an occasional ringing or buzzing in our ears. It's annoying, and then it goes away. But what if the noise rarely quiets down? What if it's there all the time? There's a name for that: Tinnitus. "It's the perception of a sound in the absence of an external sound source," says Meghan Hiss, an audiologist at The Ohio State University Wexner Medical Center.

Tinnitus isn't limited to ringing or buzzing. Some people perceive it as humming, roaring, or hissing. The sound can be soft or loud, high-pitched or low. It can be constant or off and on. While some people experience it in one ear, others hear it in both. Even the pronunciation has no agreed-upon sound: Some say TINN-a-tus, while others say ti-NIGHT-us. Both are correct.

The American Tinnitus Association estimates that about 50 million Americans experience some form of the condition. According to the National Health Interview Survey, more than 11% of Americans hear ringing in their ears, at least occasionally. And although it's more common in adults than children, it can affect people at any age.

What causes tinnitus?

According to the American Tinnitus Association, tinnitus is not itself a disease. Instead, it's a symptom of another health condition, which is often related to damage in the ear or auditory system. That means the list of possible causes is long. Tinnitus could result from age-related or other hearing loss, or a head injury. Some medications, frequent ear or sinus infections, and diseases of the heart or blood vessels can also bring on the buzz.

To understand how tinnitus causes ringing ears, you must first understand how your brain perceives sound. Through patterns of electrical activity, nerve cells create a perception of your sensory environment, says Daniel Polley, PhD, director of the Lauer Tinnitus Research Center at Massachusetts Eye and Ear in Boston. He's also a professor of otolaryngology at Harvard Medical School. These nerve cells, called neurons, have no direct contact with sound waves. "It may sound like a sci-fi movie, but how we experience reality is actually millions of tiny electrical sparks ignited by cells in the silent darkness of our skull," says Polley.

Of course, neurons don't just spark randomly—they're not supposed to, anyway. In people without tinnitus, the nerve cells respond to signals coming from your eardrum, a membrane that does, in fact, have contact with sound waves.

Tinnitus upends this process. It changes how the brain translates messages from the world around us.

Most often, tinnitus is triggered by a problem in the ear, says Polley. It could be damage to sensory hair cells or nerve endings. Or it could stem from a disruption in how the ear converts sound waves.

Sometimes there are causes that have nothing to do with the ear itself. "Severe tinnitus can happen in people with perfectly healthy ears who have had a shoulder or neck injury, or even in people who decrease their doses of anti-anxiety medications too quickly," says Polley.

Ultimately, the source of the damage—the trigger—isn't terribly important, he says. What they all have in common is a change in the balance of "go" and "stop" signals in the brain's auditory processing centers.

When the signal is weak or hard to decipher, the brain tries to compensate by making the neurons ultrasensitive. Often, it overshoots the mark. The neurons become so sensitive that they begin to activate themselves, creating a feedback loop that produces the constant perception of a phantom sound. "Eliminating input from the ear in people with tinnitus does not eliminate the phantom sound," Polley says. "Unfortunately, it can make it far worse."

Treating tinnitus

The first step in addressing tinnitus is to schedule an appointment with your healthcare provider. She or he will want to rule out conditions that may be the root of the problem. If your tinnitus is caused by something like vascular disease or a problem with your jaw, addressing those issues may ease the din.

But often, the cause remains a mystery. In those cases, there are several options for coping, says Hiss, although there are no guarantees. These options include:

• Hearing aids: Tinnitus is often associated with at least some level of hearing loss. So, after ruling out other medical causes, Hiss recommends seeing an audiologist. Improved hearing may make the buzzing less bothersome, because you'll be less focused on it and hear more environmental sounds instead. Additionally, some hearing aids have a built-in tinnitus-masking feature that can help reduce a person's perception of tinnitus.
• Sound therapy: Having another continuous (and pleasant) sound to focus on can seem to turn the volume down on the irritating noise. Something as simple as a fan might do the trick. You can also try sound machines or smartphone apps that produce white noise or nature sounds, such as chirping birds or babbling brooks.
• Cognitive behavioral therapy: CBT can help tinnitus sufferers learn strategies that help them direct their attention away from the buzz or hum. It can also help you handle the stress and worries that tend to accompany the noise. "At this point, this is the best we have," says Polley. "And many people with severe tinnitus are thankful for it."

The most important thing is that you don’t allow yourself to suffer needlessly when there are treatment options available. It may take some trial and error to discover what works, but eventually, you’ll override your misfiring neurons and restore the peace and quiet you deserve.