The Sound Barrier #2: The noise that isn't there

0:00When I scraped my car in that parking garage, I was worried that it could be a long process to take care of it. Like a landscaper's first day trimming a hedgeman. I have definitely already been here. Now was it left, right, or right, left? Well, maybe I'll cut a path out and find my way back later. But it wasn't like that. I filed a claim in under two minutes on the GEICO app, and they handled it from there. It was taken care of almost as quickly as it happened. It feels good to get help quick. It feels good to GEICO. Support for this show comes from Fetch Pet Insurance. Do you have a pet? Every six seconds, a pet owner in the U.S.

0:38gets hit with a vet bill of over$1 ,000. And it's almost always an unwelcome surprise. That's where Fetch Pet Insurance comes in. Fetch is the most complete pet insurance. Get paid back up to 90 % of vet bills. You can use any vet in the U.S. and Canada. All vets are in network. Go to FetchPet.com slash save right now for your free quote. That's FetchPet.com slash save.

1:11I noticed it around just New Year's time. I just remember there was something on the bright side of my ear going on. It's like...

1:28And I thought it was just the pipes. I kept asking my fiancé if he's been hearing something going on in the walls next to me. But he's reported back nothing.

1:39Kelly 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. 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. Wow, so different sounds, right, in left ear? Yeah. Eventually, Kelly decided she needed to get her hearing checked.

2:16They've done so many tests on me, and I don't have anything wrong with my hearing. 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.

2:59They didn't take her seriously. Because they had no idea what living with tinnitus actually feels like. 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 there's nothing else to do. Like, no way to escape it.

3:30Yeah, I'm sorry. Kelly's tinnitus got worse in louder environments, so she had to leave her job. She stopped seeing her friends. She couldn't sleep. 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. Kelly and I first got in touch because she listened to our episode on hearing, the one just above this in the feed, and she wrote in. When I was listening to that episode, that's all it was making me think about, and that's why I was like, should I reach out?

4:09I hadn't been planning to look into tinnitus, but the more I talked to Kelly, the more I realized just how mysterious it is, even to the people who have it. So I wanted to try and get her some answers. I'm curious if you have any questions that you want me to ask a scientist. I guess I would just want to know more, you know? 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. In the last episode, we talked about how our brain constructs the world we hear, How it has this superpower where it can edit out unwanted noise and fill in gaps and create a world of sound that we're actually able to understand.

4:58Tinnitus is that superpower gone wrong. 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? and what can we do about it?

5:41Okay, before you go into this, just a question. How do you pronounce this word? Tinnitus. So you've got two ways of saying it. Tinnitus is, I believe, the proper way of saying it. Most people say tinnitus. It doesn't matter as long as we understand what we're talking about, but I believe the proper way is tinnitus. A couple weeks ago, I met Stéphane Maison at Mass Eye and Ear, a hospital in Boston. Stéphane's the director of the tinnitus clinic there, which he launched last year. The vast, vast, vast majority of the patients are being told, there's nothing I can do for you, goodbye. I've seen some patients who are like borderline suicidal.

6:25And 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 TNT's clinic. It was also a way to potentially help his own hearing. I have team piece. You do? Yeah. What does it sound like? High pitch. Since when? I have team piece 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. So do you hear a pitch right now? Yeah.

7:10You've probably also had at least a brief moment of tinnitus before. 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. 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. As you no longer receive some information in one particular area, the adjacent area is going to start to become hyperactive. It's kind of like a climate control system.

7:50You 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, it turns up the volume in your head. So now you start to perceive a sound that is not there. 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. The leg is gone, but you start to feel pain where it's missing. your brain is artificially increasing the perception.

8:31So in the case of touch, if I touch my finger like this, you're going to feel my finger. If I increase the perception, that's going to turn into pain. 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? 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.

9:20So 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, Raise your hand whenever you can hear a beep. 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. But a hearing test does not tell you the whole story. Our ears can do so much more than just listen to beeps. There's something I like to tell my patient.

10:00If everything is fine, you should be able to hear a pin drop. Or you should be able to hear an explosion. If you think about it, that's a gigantic dynamic range. 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. 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.

10:50This 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. The fibers that are the most susceptible to aging and noise exposure are the fibers that could fall loud sounds. 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.

11:34And 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. 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. 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.

12:15Instead of testing them in quiet, it's as if someone was speaking super fast with a little bit of reverberation. 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 he ran a different test. He placed tiny electrodes inside their ear canals, and he played them a sound. A click. He recorded the electrical responses from that sound. And that's going to show you different types of waveforms.

12:58It'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. So now you're looking at the brainstem response. And interestingly, the participants with tinnitus had a response as big as those who never had tinnitus.

13:39For 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. Somehow, the brain is able to catch up. 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. Tinnitus is not a sound in your ears. Tinnitus is generated at the central nervous system. 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.

14:25Like, 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. Do you have any idea what you think might have caused this? I know the friend of mine has tinnitus because he played in a metal band. You know, like... That's how I wish I would have lost it. I know, it's a cooler way to have tinnitus. Yeah, it is.

15:06I mean, do you have any ideas? No, I mean, the only link that had seemed to make sense was like, my friend had sent me the article about the COVID vaccinations and how a lot of people were developing tinnitus. That was the only time frame I could really sync up. I've heard this theory from a lot of people. So ask Stefan. I've seen a bunch of patients that said, I had the COVID vaccine and then my tincture showed up. I have zero evidence of a relationship between COVID vaccine and tinnitus. I have no evidence for that. The issue is that we didn't test people before they got the COVID vaccine. So there's no baseline.

15:51But at a time when so many people were getting COVID vaccines, it felt pretty easy to be like, okay, I just got a vaccine and now I have tinnitus. It must be connected. But it doesn't seem like it is. So yeah, we know hearing damage can lead to tinnitus, but we don't know what actually flips that switch. Why some people hear that noise and other people don't. And more importantly, we don't really know what to do about it. how to fix it, or even how to make it better. But we might be on the verge of a big step forward. That's in a minute.

16:31Support for this show comes from Shopify. Starting a business is not easy. It can come with a lot of self-doubt and questions like, what if I fail? Or what if nobody buys what I have to sell? But if you are a small business owner pushing through that self-doubt, Shopify wants you to know that it is there to help along the way. Shopify is the commerce platform behind millions of businesses around the world. And according to their numbers, 10 % of all e-commerce in the U.S. From household names like Magic Spoon to brands just getting started. Their design studio lets you build a beautiful online store that matches your brand style.

17:09They offer a host of helpful AI tools, plus built-in marketing tools to help you create effective email and social media campaigns. And if you ever get stuck, their award-winning 24-7 customer support has your back. It is time to turn those what-ifs into Shopify today. Sign up for your$1 per month trial today at shopify.com slash unexplainable. Go to shopify.com slash unexplainable. That is shopify.com slash unexplainable.

17:45Support for the show comes from Quince. The other day I was out shopping, picked up a cute dress, but I wasn't totally sure it was my style because I've been kind of moving away from sleeveless stuff lately. Then I brought it home and tried it on over a little lightweight black T-shirt that I got from Quince. And I am literally wearing the whole outfit right now as I record this ad. The shirt from Quince was just the perfect thing to pair with the dress to give it sleeves. And the shirt is light and breathable enough that I'm not like sitting in the studio too warm. So as a person who loves to layer clothing, I really, really appreciate that Quince has a wide array of shirts and a whole bunch of different cuts.

18:32Lots of options for people like me. But if you are looking for not just shirts, but a whole range of lighter, cooler wardrobe pieces as part of a summer refresh, Quince also has you covered. Quince can help you find some new, breathable outfits that are easy to wear and still look put together. Elevate your summer wardrobe. Go to quince.com slash unexplainable for free shipping on your order and 365-day returns. now available in Canada too. So that is q-u-i-n-c-e dot com slash unexplainable for free shipping and 365 day returns. quince.com slash unexplainable.

19:13We all do it. You have a night for yourself, but don't like the sound of the silence. So you turn on the TV just for the ambience. It's a little trick that helps you feel like you've got company and aren't alone. And other insurers, well, they may make you feel alone. But when you switch to Geico, you've got claims reps available around the clock. So whenever you need, you'll have people around to help. And let's turn on the washing machine, just for good measure. Oh, isn't that soothing? It feels good to have support. It feels good to Geico.

19:48Had I not told you that what you mistake for madness is but over-acuteness of the senses? 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. I found this YouTuber who makes these, like, white noises, or he calls them pink noise, brown noises. There's so many different ones. This is the 15 kilohertz tinnitus audio noise masker right around 15 ,000 hertz. And I see so many people in the comments talking about how this has helped them, like, go to sleep at least for, like, a few hours. Ringing sometimes can be interrupted by introducing a new and different sound close to the frequency of the ringing.

20:32It may work, it may not, and it'll probably only work to a certain degree. My fiancé had found a way to extract one of the audios, and he combined that with just rain sounds. And he made it so that the rain sounds would only play on the right side and the left side for just the white noise. and he even put that on the TV for us so that I could play it on the soundbar and I could go to sleep to it. So I've been sleeping a little more because of that too, you know? 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.

21:14But 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. It's just a band-aid. I don't think it's very useful. 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.

21:54And the more you think about tinnitus, the worse it can get. We're talking about this right now, so I can hear it much louder, thanks to you. Sorry. But I know it's because I'm paying attention to it. 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. So Stefan is hoping for a more permanent solution. He told me about this experiment where researchers injected these proteins called neurotrophins into the ears of mice. And he saw that the connections between the auditory nerve fibers started to regrow.

22:37Kind of like how you might restore connections in a power line. Which makes Stefan wonder if the same thing might be possible in humans. What if you could bring back those fibers? What if you could bring back that signal to the central nervous system? Perhaps, it's a big perhaps, you could reduce that hyper-excitability in the brain. Stefan's hoping to get a human trial off the ground sometime soon. But like with a lot of scientific research right now, things are kind of up in the air. Well, who knows? Well, that depends on FDA. So right now, we have to go step by step. This idea would be like fixing the hardware of our hearing system.

23:20But if that isn't possible, what about fixing the software? Retraining the brain so it just stops generating that tinnitus sound? One of the researchers at the forefront of this idea is Susan Shore. She's a professor emerita at Michigan. And she's been trying to figure out how to retrain the brain by combining hearing with our sense of touch. People who have tinnitus can sometimes modulate their tinnitus by clenching their jaw, raising their eyebrows, and this kind of thing. Even shrugging your shoulders can change the pitch or the volume of the tinnitus. The way our brains are wired, there's a lot of crossover between our auditory system and our touch system.

24:03Certain neurons actually get input from both sound and touch. And Susan thought she might be able to use this as a way to retrain the hyperactive neurons causing that tinnitus sound. So Susan and her team, they tested the idea out on guinea pigs. The results were promising. So they recruited people with tinnitus. They had them wear headphones. They'd play them a sound. It's a burst of sound. Just like a beep, like that. It's more like psh, psh, psh. They'd ask them things like, Is your tinnitus noisy? Is it more pitchy? Is it more tonal? Until they were like, yeah, that's my exact tinnitus sound.

24:42Then they attached electrodes to the back of people's necks. They played them their particular tinnitus sound while also giving them an electric pulse. They gave both of them in a precise order and time interval. They repeated it for 30 minutes a day. And they found that they could retrain the hyperactive neurons that were leading to the tinnitus. that they could basically get these neurons to calm down. In our first trial, we did four weeks. And we found that we got a clinically significant decrease in people's tinnitus. So they did a second trial for six weeks. We saw a progressive decrease in their tinnitus.

25:21And then when we stopped doing the stimulation, that continued to decrease for another six weeks. Wow. So that's really indicating a long-term plasticity, that this decrease continued even after we'd stopped the treatment. And do you have longer data than that? We don't. That has to be data collected in the field. This isn't a cure. It didn't necessarily eliminate the sound. But it did make it less intense for over half the participants. Susan and her team also acknowledged that the placebo effect could have been behind some of the improvement. But they don't think it was the main driver. And the results do seem promising.

26:01Still, there are a lot of major hurdles to come here. Susan's company, Oracle, still needs to get FDA approval. They may need to do more trials. And it'll probably be years before anyone is using this kind of tech outside of a research setting. So I'd gotten two interesting ideas. Neither of them seemed perfect or ready. And 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 Polley. I have tinnitus, and whenever I want to, I can hear that beautiful symphony of that pure tone. Dan's a tinnitus researcher who also has tinnitus, like Stefan, and apparently a whole bunch of tinnitus researchers, as I found out.