The noise that isn't there

Almost 15% of adults suffer from a persistent, often intolerable sound... that is literally just in their heads. Why does the brain do this to us? We help one of our listeners get some answers. This is the second episode of a five-part series calledThe Sound Barrier https://www.vox.com/podcasts/467048/unexplainable-hearing-audio-podcast-brain from our friends at Vox's Unexplainable podcast. Guests: Stéphane Maison https://doctors.masseyeandear.org/details/66, director of the tinnitus clinic at Mass Eye and Ear and Dan Polley https://oto.hms.harvard.edu/people/daniel-polley, tinnitus researcher at Mass Eye and Ear See pcm.adswizz.com https://pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. NPR Privacy Policy https://www.npr.org/about-npr/179878450/privacy-policy

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Speaker 00

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• 0:16Emily Kwong?

  Hi, short wavers. Emily Kwong here, and we have a special episode for you from one of the best science podcasts out there, Unexplainable from Vox. Unexplainable digs into scientific mysteries and unanswered questions about everything from dark matter and black holes to what dinosaurs may have sounded like. And last year, host Noam Hassanfeld did a five-part series about the way our brains process sound. It's called The Sound Barrier, and their second episode is about tinnitus. That's when you perceive a ringing in your ear, this persistent sound that comes from nowhere. Almost 15% of adults suffer from this, and there is no cure. In fact, researchers are only just beginning to understand the cause.

• 0:58Emily Kwong?

  Here's that piece, and you can check out the rest of the Sound Barrier series on the Unexplainable podcast feed. Enjoy.

• 1:11Speaker 02

  I noticed it around just New Year's time. I just remember there was something on the right side of my ear going on. It's like

• 1:27Speaker 02

  And I thought it was just the pipes. I kept asking my fiance if he's been hearing something going on in the walls next to me, but he's reported back nothing.

• 1:38Speaker 03

  Kelly started hearing things almost four years ago, just a couple months after her 25th birthday. At first, she wasn't sure what was going on. She did the WebMD thing. She Googled all her symptoms. She got worried. When she told her family, they told her to relax. But the sound didn't stop, and pretty soon, she started hearing something in her other ear.

• 2:00Speaker 02

  It's like the high-pitched ringing you usually hear in your ear every now and then, but it's like more intense, and it's just there the whole time.

• 2:07Speaker 03

  Wow, so different sounds, right, in left ear?

• 2:10Speaker 02

  Yeah.

• 2:11Speaker 03

  Eventually, Kelly decided she needed to get her hearing checked.

• 2:15Speaker 02

  They've done so many tests on me, and I don't have anything wrong with my hearing.

• 2:21Speaker 03

  Almost 15% of all adults have had tinnitus, and 100 million of them have severe tinnitus, like Kelly. They hear persistent noises, ringing, buzzing, sirens, even construction or drilling sounds, which seriously impact their life. But when a lot of them get their hearing checked, the test comes back fine. It's one of the things that makes tinnitus so maddening. Why would so many people keep hearing noises like these if the test says there's nothing wrong with them? And it's not like most of the people Kelly was talking to were any more help. They didn't take her seriously because they had no idea what living with tinnitus actually feels like.

• 3:06Speaker 02

  I mean, it's like you're just trapped in a room with a crying kid. You can't stop crying or anything. You don't know how to just make it stop. It's like no way to escape it. Yeah, I'm sorry.

• 3:29Speaker 03

  Kelly's tinnitus got worse in louder environments, so she had to leave her job. She stopped seeing her friends. She couldn't sleep.

• 3:37Speaker 02

  I would isolate myself and everything. I've grown so distant from my friends because with the lack of sleep, you're just not in any other mood for anybody. And you can't show up like you used to for any of the things that you've done.

• 3:51Speaker 03

  The thing that makes tinnitus so hard to pin down is that it isn't a sound out there in the world. It is literally just in your head. But it's also real, especially for people like Kelly. I'm Noam Hassenfeld, and this is the second episode of The Sound Barrier, a series from Unexplainable about the limits of hearing and the ways we can break through. On today's episode, how can our brain make us hear sounds that don't exist?

• 4:42Speaker 03

  Okay, before you go into this, just a question. How do you pronounce this word?

• 4:49Speaker 04

  Tinnitus.

• 4:51Speaker 04

  So you've got two ways of saying it. Tinnitus is, I believe, the proper way of saying it. Most people say tinnitus. Doesn't matter as long as we understand what we're talking about.

• 5:05Speaker 03

  A couple of weeks ago, I met Stephane Maison at Mass Ionier, a hospital in Boston. Stephane's the director of the tinnitus clinic there, which he launched last year.

• 5:14Speaker 04

  The vast, vast, vast majority of the patients are being told, "This is a thing I can do for you. Goodbye." I've seen some patients who are borderline suicidal. And so I was interested in being able to provide some beginning of an answer to those patients and to provide support to those patients. And that's why we opened the tinnitus clinic.

• 5:39Speaker 03

  It was also a way to potentially help his own hearing.

• 5:42Speaker 04

  I have tinnitus.

• 5:43Speaker 03

  You do?

• 5:44Speaker 04

  Yeah.

• 5:45Speaker 03

  What does it sound like?

• 5:47Speaker 04

  High pitch.

• 5:48Speaker 03

  Since when?

• 5:50Speaker 04

  I have tinnitus for the past like 12 years, something like that. I haven't been in a club in many, many years, or even decades, but I can tell you that I abuse my ears.

• 6:02Speaker 03

  So do you hear a pitch right now?

• 6:05Speaker 04

  Yep.

• 6:09Speaker 03

  You've probably also had at least a brief moment of tinnitus before.

• 6:14Speaker 04

  Some people will go to a concert, they feel that as they leave the concert, the hearing is not quite the same. You feel that your hearing is a little bit muffled. You can even experience that ringing in your ears.

• 6:27Speaker 03

  Basically, your hearing gets damaged, which means one part of your brain is getting less auditory information than it expects. So another part starts to overcompensate.

• 6:37Speaker 04

  As you no longer receive some information in one particular area, the adjacent area is going to start to become hyperactive.

• 6:47Speaker 03

  It's kind of like a climate control system. You have it set to 70 degrees or something, and if it gets too cold, the heat will kick on. So when the brain suddenly isn't getting the same level of sound it's expecting from the outside world...

• 7:02Speaker 03

  It turns up the volume in your head.

• 7:05Speaker 04

  So now you start to perceive a sound that is not there.

• 7:10Speaker 03

  Usually, this kind of post-concert ringing sound goes away. But chronic tinnitus is when that ringing doesn't stop. Stefan told me it's sort of like phantom limb pain in people who've lost a leg.

• 7:22Speaker 04

  The leg is gone, but you start to feel pain where it's missing. Your brain is artificially increasing the perception. So in the case of touch, if you touch you with my finger like this, you're going to feel my finger. But if I increase the perception, that's going to turn into pain.

• 7:40Speaker 03

  Sometimes, people with tinnitus can pinpoint what caused it. I spoke to one researcher who told me his tinnitus was caused by sitting too close to a bagpipe band at his friend's wedding. But often, tinnitus seems like it comes out of nowhere. Like with Kelly, people just wake up one day and hear this phantom ringing. And just like Kelly did, a lot of them go get a hearing test. And it often tells them their hearing is fine. So what's going on?

• 8:08Speaker 04

  If tinnitus is the result of the hyperactivity of the brain because something is missing, then people with normal hearing tests should not have tinnitus.

• 8:19Speaker 03

  So let's talk about that hearing test, the kind that tinnitus patients like Kelly get all the time. You sit in a soundproof booth, you put on headphones. The audiologist plays you a pure tone, and they say,

• 8:32Speaker 04

  Raise your hand whenever you can hear a beep.

• 8:35Speaker 03

  The audiologist keeps playing the same sound softer and softer until you stop raising your hand. And then they do the same thing for a whole bunch of different pitches. This is the gold standard for hearing tests.

• 8:48Speaker 04

  But a hearing test does not tell you the whole story.

• 8:53Speaker 03

  Our ears can do so much more than just listen to beeps.

• 8:57Speaker 04

  There's something I like to tell my patients. If everything is fine, you should be able to hear a pin drop,

• 9:05Speaker 04

  or you should be able to hear an explosion. If you think about it, that's a gigantic dynamic range.

• 9:14Speaker 03

  Our ears can do this because they have different types of auditory nerve fibers, these wires that carry sound signals from the inner ear to the brain. Some of them pick up soft sounds, and other ones pick up loud sounds. But the hearing evaluation only tests for soft sounds.

• 9:31Speaker 04

  And if the fibers that respond to loud sounds are missing, this is not going to affect whatsoever your hearing test. So the gold standard of hearing evaluation around the world to this day is completely insensitive to the loss of those fibers.

• 9:49Speaker 03

  This is how someone like Kelly can have hearing problems while still having a perfectly normal hearing test. It's called hidden hearing loss. And it was only discovered a few years ago when researchers at Mass Eye and Ear realized just how easy it was to damage those louder nerve fibers.

• 10:05Speaker 04

  The fibers that are the most susceptible to aging and noise exposure are the fibers that could for loud sounds.

• 10:16Speaker 03

  The idea is that if you have tinnitus, at some point in the past, you probably damaged your hearing. Specifically, you damaged those louder fibers. But your symptoms might have gone away. And because normal hearing tests don't focus on loud fibers, that damage stayed hidden. And if your loud fibers get damaged, you're not going to have any issues having a conversation in a quiet room. You're not going to have any issues on your hearing test. But if you go somewhere, like a bar or a restaurant, you might find that you suddenly can't make out what your friend is saying.

• 10:49Speaker 04

  And if you look at most people, that's something very, very common. They feel like they don't have any issues in a quiet environment, but as soon as they go to a bar or a restaurant, they start to struggle.

• 11:04Speaker 03

  So Stefan took his patients with normal hearing test scores. And instead of giving them that classic hearing test again, he gave them a different one focused on loud fibers.

• 11:14Speaker 04

  Instead of testing them in quiet, it's as if someone was speaking super fast with a little bit of reverberation.

• 11:22Speaker 03

  Like he suspected, a lot of them really struggled with the louder, echoey conversations because they had hidden hearing loss. They had damage to their loud fibers. And Stefan had a feeling that hidden hearing loss could be the thing causing his patients that had normal hearing test scores to have tinnitus. So we ran a different test. He placed tiny electrodes inside their ear canals and he played them a sound.

• 11:49Speaker 04

  A click.

• 11:51Speaker 03

  He recorded the electrical responses from that sound.

• 11:54Speaker 04

  And that's going to show you different types of waveforms.

• 11:58Speaker 03

  It's basically a squiggly line that shows neurons firing as a sound signal gets processed by the brain. And when he looked at the early peaks, which show the auditory nerve in the inner ear, he saw way less firing than normal. The patients were getting less sound input because they had hidden hearing loss. But then he looked at the later peaks on the squiggle, the ones that showed what happened as the sound signal winds its way into the brain.

• 12:24Speaker 04

  So now you're looking at the brainstem response. And interestingly, the participant 15th is had response as big as those who never had tinnitus.

• 12:39Speaker 03

  For tinnitus patients, the peak at the brainstem was larger than at the nerve. Something was making up for the hidden hearing loss and turning the volume up.

• 12:49Speaker 04

  Somehow, the brain is able to catch up.

• 12:53Speaker 03

  Stefan was basically seeing the seeds of tinnitus on this squiggle graph, this thing that didn't show up in normal hearing tests, this thing that so many patients had been told wasn't real. He saw it happening.

• 13:07Speaker 04

  Tinnitus is not a sound in your ears. Tinnitus is generated at the central nervous system.

• 13:17Speaker 03

  The idea that hidden hearing loss is directly related to tinnitus, it's a big step forward, but there's still so much we don't know. Like, we know the basics, that tinnitus usually starts with hearing loss, which can be caused by things like listening to loud music, or a virus, or aging. But not everyone with hearing loss hears this constant ringing. Scientists still don't really understand what takes someone from hearing damage to tinnitus, why this happens for some people and not others.

• 13:53Speaker 05

  Had I not told you that what you mistake for madness is but overacuteness of the senses?

• 14:01Speaker 03

  Once she got diagnosed with tinnitus, Kelly started doing all kinds of research online. She was trying to find anything that could help her feel better.

• 14:08Speaker 02

  I found this YouTuber who makes these like white noises, or he calls them pink noise, brown noises. There's so many different ones.

• 14:16Speaker 06

  This is the 15 kilohertz tinnitus audio noise masker, right around 15,000 hertz.

• 14:25Speaker 03

  This kind of thing is called a masker because it masks the sound of tinnitus. And Kelly eventually went to her audiologist to get hearing aids that played these sounds for her all the time. But because the hearing aids also amplify sounds, she had to wear earmuffs over them, too, which isn't great when you're in your 20s and just trying to go outside. So, all in all, it's been helpful, but it's far from perfect. And Stefan isn't really a huge fan of stuff like this to begin with.

• 14:53Speaker 04

  It's just a Band-Aid. I don't think it's very useful.

• 14:58Speaker 03

  Stefan says that even though a masker is designed to blend the tinnitus noise in with the background, it ends up becoming the majority of what people are actually hearing. In his experience, masking noise just ends up reminding patients all the time that they still have tinnitus. And the more you think about tinnitus, the worse it can get.

• 15:18Speaker 04

  We're talking about this right now, so I can hear it much louder, thanks to you.

• 15:25Speaker 04

  Sorry.

• 15:28Speaker 04

  But I know it's because I'm paying attention to it.

• 15:32Speaker 03

  For some people with mild tinnitus, a Band-Aid like this can be useful from time to time. But for people like Kelly with severe tinnitus, it's a lot more complicated. I wanted to be able to go back to Kelly with some useful information, but I wasn't really sure what I was going to be able to tell her until I talked to Dan Polly.

• 15:51Speaker 07

  I have tinnitus and like whenever I want to, I can hear that beautiful symphony of that pure tone.

• 15:57Speaker 03

  Dan's a tinnitus researcher who also has tinnitus, like Stefan, and apparently a whole bunch of tinnitus researchers, as I found out. Dan also works at Mass Ionier, and he focuses on how different parts of the brain work together to generate the tinnitus sound.

• 16:14Speaker 07

  Because the brain doesn't have direct contact with the physical world, everything that we perceive as consciousness is constructed from the activity of the brain.

• 16:24Speaker 03

  Dan told me there's a pretty fundamental difference between the mild tinnitus he has and the severe tinnitus that people like Kelly have.

• 16:34Speaker 07

  People with really severe tinnitus have like a whole brain problem. Their tinnitus has expanded and it's incorporated like other brain networks. And whatever hyperactivity in my auditory pathway that's causing me to perceive a sound that isn't there, it hasn't changed the ability of my executive control to concentrate, or it hasn't reprogrammed my limbic system to find all sounds horribly aversive and make me depressed.

• 17:00Speaker 03

  You're saying when some people are obsessed and can't function because their tinnitus, it's not because they just hate the sound, it's because that sound has gotten into their brain system and like infected their brain?

• 17:15Speaker 07

  Yeah, it isn't actually that their tinnitus is louder. That hyperactivity spilled over and recruited other brain systems that have nothing to do with hearing per se, but with your ability to concentrate, to sleep, to like regulate mood and emotion. They have a more widespread network of dysregulation in their brain than I do.

• 17:34Speaker 03

  For people with severe tinnitus, Dan says things like mindfulness therapy or cognitive behavioral therapy can act on these other brain areas and hopefully tamp down the tinnitus.

• 17:46Speaker 07

  They can take you from like, I have tinnitus disorder, I'm not sleeping, I'm depressed, I'm socially withdrawn, and they can turn you into somebody like me, who like, it's like a little bit annoying, but if you can take the one in 10 who's severely debilitated by their tinnitus and turn them into like the other nine, I'd still take that as a something useful.

• 18:13Speaker 03

  Yeah, so it's been almost a year since we talked. How are you doing?

• 18:19Speaker 02

  I've been doing a lot better, I would say, honestly, like, I've been happy, I guess. I've just been trying to be more open about it because I realized that I never shared it to anyone at my job. Now I'm just like trying to just put myself out there again. It just closes you in this insane box, you know? You have nowhere to go. And you just somehow find a way to chisel through it.

• 18:47Speaker 03

  And you feel like you're slowly chiseling through it?

• 18:50Speaker 02

  Chiseling, yeah, still making my way out.

• 18:56Speaker 03

  I told Kelly what Dan had said about people with severe tinnitus. How it's not like they're just being weak. That they might have a whole brain problem. That their tinnitus has basically expanded across their brain networks and hooked into the parts of their brain that influence other things like their emotions.

• 19:14Speaker 02

  That's... I feel like that just feels like a better explanation. Because I've always had a hard time describing it, but it kind of makes me feel a little at ease again where I'm like, okay, maybe it's still not entirely like me, me, like, you know?

• 19:35Speaker 03

  It's gonna be a long process. But Kelly told me she's been trying to slowly phase out her maskers and her hearing aids. And she's trying to learn how to listen to the world again.

• 19:46Speaker 02

  I'm actually just spending days in my apartment only, just without my hearing aids and just trying to take in all the sounds, like I'll have the windows open because the maintenance guys are working or the gardeners and I'm even trying to like vacuum without any type of like a hearing protection and just recognizing that sound too, it just...

• 20:08Speaker 02

  Yeah.

• 20:10Speaker 03

  She still hears that tinnitus sound all the time. But as hard as it is, she's trying to stop blocking everything out. She's just trying to hear all the other sounds along with it.

• 20:23Speaker 02

  I mean, we saw a firework show for the first time in years and it was scary each time one went off, but eventually my body would stop jolting when they would because I was like, this is what we used to do. Like, it's literally just, it's really weird to, to know the world again.

• 20:59Speaker 03

  This episode was reported and produced by me, Noam Hassenfeld. I also did the music. It was edited by Joanna Salataroff with help from Jorge Just. Mixing and sound design from Christian Ayala with a ringing endorsement from Sally Helm. Meredith Hadnot runs the show. Julia Longoria is our editorial director. Unexplainable is part of the Vox Media Podcast Network.

• 21:23Speaker 04

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