Dr. Nina Kraus on the Connection Between Sound and Mind

Discover the critical difference between hearing and listening with Dr. Nina Kraus, an acclaimed expert from Northwestern University. Explore her interdisciplinary journey into the biological bases of language and the fascinating role of bird song in auditory research. Dr. Kraus also shares insights from her book, "Of Sound Mind," which celebrates the profound connection between sound and brain health, making complex concepts accessible to everyone.

Uncover the latest advancements in hearing technology, including bone conduction devices that are transforming auditory experiences for musicians and everyday users alike. We discuss the advantages of bone conduction headsets and AirPods with ambient mic features, offering practical advice on choosing the right hearing aid or headset. Additionally, learn about the importance of hearing protection with innovative tools like the 3DME, and understand the broader health impacts of constant noise exposure in our modern world. This episode merges cutting-edge science, technology, and actionable tips to enhance your auditory experiences and protect your hearing health.

While we know all hearing aids amplify sounds to help you hear them, Starkey Genesis AI uses cutting-edge technology designed to help you understand them, too.

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Chapters

• 0:19 Advances in Hearing Technology and Research
• 9:30 Innovative Hearing Solutions for Music
• 18:23 The Impact of Hearing Technology

Transcript

Blaise Delfino, M.S. - HIS:

You're tuned into The Hearing Matters podcast, the show that discusses hearing technology, best practices, and a global epidemic hearing loss. Before we kick this episode off, a special thank you to our partners, Redux, faster dryer, smarter, verified. Sycle, built for the entire hearing care practice. Fader Plugs, the world's first custom adjustable earplug. Welcome back to another episode of The Hearing Matters podcast. I'm your founder and host, Blaise Delfino, and as a friendly reminder, this podcast is separate from my work at Starkey.

Dr. Douglas L. Beck:

Good afternoon. This is Dr. Douglas Beck with The Hearing Matters podcast. Today, my guest is the very famous, Dr. Nina Kraus, from Chicago. Dr. Kraus is the Knowles Professor of Communication and Sciences, Neurobiology, Linguistics and Otolaryngology at Northwestern University. She founded and directs the Auditory Neuroscience lab, also known as Brainvolts. Dr. Kraus is the director of Northwestern University Knowles Hearing Center, and is a Guggenheim fellow, and she is a biologist and an amateur musician. Dr. Kraus thinks about sound and brain health all the time, and she takes pride in being a citizen of several scientific fields that her research is not constrained to the lab and her discoveries have impacted education, health and social policy. Dr. Kraus, welcome. I'm so glad you're here.

Dr. Nina Kraus:

I'm so glad I'm here with you.

Dr. Douglas L. Beck:

Well, and we've had interviews over the years. I think we've done four or five in the last 20, 25 years, and most of them have been written. It's about time that we got onto this video medium where we could actually have a conversation and see each other. It's very nice. Most people, when I talk about Dr. Kraus and her very, very important work, they're surprised to know you're not an audiologist. When I say that you're a PhD in biology, they're sort of shocked, but you talk about that as far as being multidisciplinary. Tell me a little bit about how did you get your PhD in neurobio and how did that get you to all these studies in audiology?

Dr. Nina Kraus:

Well, I grew up in a house where more than one language was spoken, had a mom who was a pianist, and there was lots of music around, so sound was important. I went to Swarthmore College, I majored in comparative literature because I liked to read and I knew some languages. Then I took a biology class, and that changed my life together with having discovered a book by Eric Lenneberg that was called The Biological Basis of Language and I thought, "Oh, yeah, this is where I belong." This is an intersection of field where I do feel is at the intersection of worlds, and I feel that way scientifically very, very strongly, and I love it there. It's my home. It's the spot I belong in.

Dr. Douglas L. Beck:

I think as you've matured as an author, as a lecturer, as a scientist, you find all these areas actually overlap.

Dr. Nina Kraus:

Yeah, absolutely. I'm not an audiologist and I don't really know that much about audiology. It's just that many of my interests very much intersect with audiology, and I feel that I would really like to see audiology burgeon with many of the ideas that we discovered as scientists. I'm just a biologist.

Dr. Douglas L. Beck:

Just a biologist. I remember reading your work 25, 30 years ago on mismatched negativity and P300s and all that, but you don't know that much about audiology. Okay, we'll go with that. Listen, I want to mention for folks who are not aware, and I think most of the hearing care professionals are, your book in 2021, Of Sound Mind was absolutely an amazing read. You and I did an interview on the book in Hearing Review in 2021. I remember it was so much fun because you wrote that book as a scientist, but in plain speak. It was written, I think for the layperson, which is an amazing opportunity for consumers, for people with hearing and listening disorders to actually catch up to some of the science in fairly simple terms.

Dr. Nina Kraus:

It's my love letter to sound.

Dr. Douglas L. Beck:

I love that

Dr. Nina Kraus:

It really is for a curious audience. It doesn't matter how much or how little you know about hearing, reading that book. I'm becoming more and more interested in just being an advocate for hearing and listening and sound, us hearing professionals so that we are armed with as much information as possible.

Dr. Douglas L. Beck:

In that book, there was one very fun, well, there are a lot of fun chapters, but I remember when I was previewing the book prior to its publication, I called you and we talked about one section where you had pointed out that birds, and I can't remember which bird in particular, if they grow up and they hear a melody sung by their mother or their father, they would always know that, that's from their mother or father. If you change the key, it would be a totally unfamiliar song to them.

Dr. Nina Kraus:

Bird hearing is fabulous in that it teaches us so much, and there is a whole chapter Of Sound Mind on bird song. We could talk for an hour about birds and bird song and our noisy world, it keeps us from hearing them, and from birds, from singing as intricately as they can.

Dr. Douglas L. Beck:

I just wanted to mention that in passing, and I want to go back to the point you raised about hearing and listening. We've talked about this you and I over the years, but hearing is just perceiving or detecting sound, and people confuse this all the time with listening. My definition, I think one that you would concur, listening is making sense of sound, comprehending sound, attributing meaning to sound where hearing is just perceiving it without any real processing. I think this is very interesting because we can hear and listen through air conduction and bone conduction, and our brain has to sort out all of this information into oral timing differences, into oral loudness differences, head shadow effect, all of that stuff and make sense of it. Well, traditionally, for people with hearing loss, people who need things louder, we can use air conduction, traditional hearing aids, we can use lots of products. Lately, in the last few years, we've come a very long way with non-traditional bone conduction type hearing aids.

You and I were corresponding a month or two ago, and you were very interested in this. I've done a little bit of work, and I'll tell you, I think the reason that so many people ignore bone conduction hearing aids is because with all due respect, for instance, bone conduction hearing aids by Johns Hopkins Medicine, hopkinsmedicine.org, and they did a fine job because they're talking mostly to patients with hearing loss, but they say, "Are you a good candidate for a bone-anchored hearing aid?" That's very different. We're not going to talk about bone-anchored hearing aids. Bone-anchored might be for people who have chronic otitis, who've had multiple mastoid surgeries and they still have drainage, maybe infection of the ear canal, maybe single-sided deafness. Lots of reasons why you might want to consider a bone-anchored hearing aid, but that's not what we're talking about. We're talking about a product that maintains an open ear canal. Tell me about your experience with this.

Dr. Nina Kraus:

Well, so I run and I have been using these Shokz headphones that a lot of people use, it turns out. You can even use them for swimming. What's nice about them is you wear them like a headband and the bone vibrators can sit somewhere on your bones, maybe right in front of your ears or your cheek, it doesn't matter. You have your ear canal unoccluded so you can hear the trucks and things that you might want to know about while you're running. I've been so surprised by the sound quality.

Dr. Douglas L. Beck:

Yeah, it's pretty good.

Dr. Nina Kraus:

I listen to classical music, I listen to metal, I listen to all kinds of different music, and the sound quality is extraordinarily good, which is why then I have been polling my audiology friends. This is one of the wonderful things about my job is that I know all these smart people who know things about hearing that I don't. I'm thinking, "Hey, wait a minute." I learned in school, and probably many audiologists learned in school, was that bone conduction is only good for very, very low frequencies, like maybe 800 hertz or so, and that's not even true.

Dr. Douglas L. Beck:

That's not true, but it was the old story.

Dr. Nina Kraus:

Science has completely reconstituted that, but that was the old story. Now we know that in fact, through bone conduction, we can hear much higher, very high frequencies.

Dr. Douglas L. Beck:

You get a really nice fidelity of sound.

Dr. Nina Kraus:

What I've been trying to do, and I'm hoping that people listening here will do, because I'm not a clinician, remember? I don't have hearing impaired people who come into my office every day. One of the big gaps and one of the big problems that we have in the hearing aid and in the hearing loss world is that hearing devices, hearing aids, cochlear implants, have been built for speech, and they're wonderful. I mean, it's just incredible. Just in my lifetime, I have seen this thing-

Dr. Douglas L. Beck:

Oh, dramatic changes.

Dr. Nina Kraus:

... flourish and develop and it's completely changing, but they are not very good at music, and music is a real problem. I'm not just talking about professional musicians, and that's a part of a whole another story, is that music is for everyone.

Dr. Douglas L. Beck:

Sure.

Dr. Nina Kraus:

Go ahead.

Dr. Douglas L. Beck:

Well, I think to a large degree, the biggest advantage I've seen with my bone conduction headset, which unfortunately I don't have at the moment, but leaving the ear canal open allows me as a musician, I can play acoustic and I can hear everything going on from there with my ear canal open. Same thing for conversational speech at a restaurant or while running, I don't run anymore. It's nice to have your ear canal open so that you can hear the environmental sounds better. This is something I was just discussing about AirPods. When you look at hearing aids, we sell about seven to 8 eight hearing aids per year in the USA. That's it. That's including the VA and Costco and everything else.

Do you know that there's 150 million AirPods that have been sold? Not a cut on AirPods, I think they're brilliant, but the beautiful thing for me when I wear my AirPods is I can have the environmental mic open or the ambient mic or whatever they want to call it, and then I can hear everything around me, even though my ears are occluded and I can hear what I intend to hear, whether it's through their noise reduction system or the Bluetooth. I think your point is that we have so many more options now because we have very good, and they're relatively inexpensive bone conduction hearing aids for runners. I would say for people with mild loss, it's certainly worth trying and see how that goes.

I looked at Amazon and I looked at Google and there's dozens and dozens. I don't want to support one or the other. I have only tried one or two myself. They've been good. I found that if you buy anything less than about 50 or 60 bucks, kind of flimsy. The stuff over a hundred bucks, 150 bucks, pretty darn good. I don't want to mention the names of the brand in particular. I know it already slipped out once, but tell me when you're running, somebody just comes up to you and says, "Hey, watch out for that dog," or something. What's your experience with that? Are you hearing it amplified?

Dr. Nina Kraus:

It doesn't have an amplifying mic, so at least my device coupled by a Bluetooth to my phone, which has my playlists or the podcast I'm listening to. By the way, works great for podcasts too, so it does speech really well.

Dr. Douglas L. Beck:

I would presume The Hearing Matters podcast is the primary one you're listening to.

Dr. Nina Kraus:

It really makes me run fast.

Dr. Douglas L. Beck:

It's a great point, and even my cheap one, I have a $60 over-the-ear bone conduction unit. I hook it up to my phone when I'm working on the yard. If somebody calls me, my ear is open. I live in Texas, so if I hear a little rattling on the ground, I might want to step away from that. I think these are opportunities for patients and for clinicians to look into because I think there are probably some patients who can only spend two or $300, and this might be very beneficial. This is a very different thing because a good over-the-counter hearing aid, the brand name stuff, if you look at them on Amazon or at the pharmacies, they're seven, $800 each, and that's average. I've looked at quite a few of them. You spend 1,500 bucks for a pair of over-the-counter hearing aids for somebody with perhaps a mild loss. This might be worth trying on the appropriate candidate.

Dr. Nina Kraus:

I encourage you to get one that like mine that cost about 150 bucks and just try it and let us know what you find. Because the way I learn things is I ask smart people and people who are positioned to know clinically and then they make me understand things that I didn't know before.

Dr. Douglas L. Beck:

The thing about bone conduction hearing aids, they actually do not have a microphone. They will work through Bluetooth to your phone, so you can take phone calls with them, you can stream music, you can listen to podcasts, you can do all those things, but they don't have an environmental mic. Now, you had a recent experience, I think with my friend Mike Santucci up in Chicago.

Dr. Nina Kraus:

Well, again, I went to Mike asking the same question I asked you, and he works with musicians all the time. Here's the idea with that. We all know that music through a hearing aid sounds not especially good. I now know enough people who say, "I love my hearing aids. I love my hearing aids, I wear them all the time for speech. When I make music or when I'm listening, I'm at a concert, I just take them off."

Dr. Douglas L. Beck:

Listen, I've been saying that to my patients for 40 years. I am a musician, you're a musician. If I just sit here and strum a Martin D-28, it's going to be 70, 80 dB. When I counsel patients about hearing aids, I say exactly what you said, these are for conversational speech. These are to help you with environmental sounds in typical environments. When you are on stage, I say to musicians, or when you're at somebody else's concert, you should be wearing hearing protection. Because that's the issue, it's the opposite of amplification. We want attenuation because the sound is very, very loud. The guidelines, and some people will say, "Oh, this doesn't apply to music, but they're about as good as we got."

Hayash says 85 dB for eight hours will cause hearing loss. They say at 90, that's four hours. At 95, 2 hours. At 100 dB, one hour. At 105 dB, 30 minutes. At 110 dB, 15 minutes before you get hearing loss. I've never been in a band that didn't play more than 110, 115 dB in a club situation. I don't recommend amplification when we're dealing with loud sounds. I don't recommend amplification for people doing target practice or hunting or any such thing. I think wearing hearing aids in that situation is very, very dangerous. I really applaud your addendum that musicians playing anything that's amplified, you probably don't need your hearing aids, and it's probably better for your overall health to take them out in that situation. Most of the time, not always, but most of the time.

Dr. Nina Kraus:

In hearing testing, one generally doesn't test below 250 hertz.

Dr. Douglas L. Beck:

That's correct.

Dr. Nina Kraus:

250 is already middle C.

Dr. Douglas L. Beck:

That's right.

Dr. Nina Kraus:

You have all these frequencies below middle C, which are really important for music and speech. Then above, you have an octave and a half above middle C before you get to 1,000 hertz. I think it's really important for audiologists to be thinking about hearing instead of just having the picture of the audiogram. We also have a piano where you can show people. Anyway, I think it's important just to know that most hearing losses are high-frequency hearing losses and you have a lot of usable low-frequency hearing. Let me talk about 3DME and how I came about learning, and one of the people that I have had a correspondence with is Nancy Williams, and I encourage you to find her.

Dr. Douglas L. Beck:

Yeah, she's a pianist.

Dr. Nina Kraus:

She is a professional, she's a concert pianist, and she has severe to profound hearing loss. She does wear hearing aids, and she has been wearing hearing aids also for playing music for a long time. She recently discovered this 3DME device and it changed her life. The 3DME works by using a fitted ear mold. You're wearing a fitted ear mold, and so the fitted ear mold protects you. It blocks out the drums and the really high intensity sounds, but it also can deliver to you, you can selectively amplify whatever you want. I haven't used one of these myself, but it's like a mixing board. You can turn up frequencies that you want to be hearing better, and at the same time, you're protecting your hearing, you can turn them up. The important piece here is that it's not going through your hearing aid because hearing aids notoriously are good for speech, but awful for many reasons that now we understand very clearly they're terrible for music.

Dr. Douglas L. Beck:

Yeah, it can be.

Dr. Nina Kraus:

This gives you your cake and you can eat it, which is the way I want to be. Of course, it's going to cost more money, but who cares if this is your hearing and your music at stake, because ideally, you'd want to have somebody who has a great hearing aid that they use all the time for speech, and then they have their 3DME device that they use for playing, making, listening to music. That's what I know.

Dr. Douglas L. Beck:

It sounds like a great option. Of course, Dr. Santucci is very famous and Sensaphonics is a leader in in-ear microphones and amplification and things like that, and all good stuff. The fact that he's involved with 3DME, I think is a huge asset for them. I'm very curious to try that myself. I love the idea. I have not tried it. Most musicians are at incredible risk for hearing loss, and so again, I would urge that this is a reasonable approach using a 3DME type product or musician's earplugs, depending on what you can do.

Dr. Nina Kraus:

With the musician earplugs, so I use the musician earplugs all the time, the Etymotic ones, and they attenuate the sound very well. Even when I'm making music, I use them, but I've had to learn. I've had to learn to play through those devices because it's different. What is nice about them is that it's passive protection. You're just sticking something in your ear canal and blocking the sound so it's not monkeying around electronically with any kind of signal.

Dr. Douglas L. Beck:

The beautiful thing about those, and I don't know why we're pitching Etymotic, but I'm sure Mead will send us a check. There's a little island of hearing in there around two or 3,000 hertz, if memory serves, so you can actually converse even with a 15 dB attenuation. Importantly, as you indicated earlier, it takes out the lowest lows and the highest highs. It's taking out a lot of the bass drums, it's taking out a lot of the bass guitar, and it's taking out the hi-hat and crash cymbals, things like that, because those are the loudest sounds. You do maintain hearing ability through some of the speech frequencies so you can communicate and you can hear, but it's taking out the most dangerous components of the sound.

Dr. Nina Kraus:

Because we know loud sounds damage, but we don't appreciate enough how much moderate level sounds really impede our health biologically. Everybody needs to know about the biological effects of moderate level sounds. People say, I am depressed, they say I'm anxious, they say I have difficulty focusing. Well, it's because of all of the moderate level sounds and alarms that we are getting, and we have good biological evidence to show this.

Dr. Douglas L. Beck:

We have all these studies that I was talking about, NIOSH and OSHA, they talk about loud sounds doing damage, but nobody ever said that 60 decibels or 40 decibels of sound all day long won't hurt you. I think this is the point is that we were as human beings, as mammals, we were never meant to be in sound 24/7, and we are. Everything from your HVAC system to your refrigerator, to your conversational speech, to restaurants, to bars, to trains, to planes, to automobiles. We're always stimulating our ears and nobody really knows the lowest level that is safe.

Dr. Nina Kraus:

Sound, as you said, is our alarm sense. We're in a constant state of moderate, mild-level alarm.

Dr. Douglas L. Beck:

Shock.

Dr. Nina Kraus:

Everybody feels it. You know when the refrigerator cycles off. Your body knew this all the time.

Dr. Douglas L. Beck:

Yeah, you relax then.

Dr. Nina Kraus:

It affects your thinking. Remember, the hearing brain is vast, read Of Sound Mind. It engages our cognitive motor reward visceral system. There are so many biological effects that I don't have time to talk about now, but actually read the-

Dr. Douglas L. Beck:

Of Sound Mind. There's a whole chapter on this.

Dr. Nina Kraus:

There's a chapter on noise. Can we talk? Let's talk about vibration and bone conduction and the fact that bone conduction, first of all, we're busting myths. First of all, it goes much higher than we thought. There's work by Frank Russo, by Eagleman, showing that deaf people, it's not even going through the ear because there isn't a cochlea that's working. There are wristbands and there is this combination of touch and sound, which is completely linked. There's a wonderful article by Candice Manning in hearing research on the effect of sensory neural hearing loss and tinnitus on speech recognition over air and bone conduction military communication headsets. It's basically showing that whether you have a hearing loss or not, the bone conduction helps you and it helps you hear. I'm hoping that the hearing aid industry and that people will develop this more because it's a whole channel of communication that I think we're missing and that you're getting, Doug, when you're playing your guitar, the thing is vibrating.

Dr. Douglas L. Beck:

Sure, and it sounds different when you're holding it and when you're listening to it, and that is bone conduction changes. The points are all well made. The difficulty that audiology faces, I think, it's 2024 and very, very few audiologists or hearing aid dispensers or ENTs will test above 8,000 hertz. We don't even have standards above 8,000 hertz as far as what might be a normal mild, moderate, severe, profound loss. We don't have standards for that, which is terrible at this time. As you say, testing below 250, also very important. We used to test 50, 60 years ago down to 125, but I think people are used to just doing the most basic tests to get to the diagnosis and move people on and I think that, that's the wrong way to do it. I think it's so important that you do 125, 250.

I do all interoctaves. I've always done 500, 750, 1,000, 1,500, 2,000, 3,000, 4,000, 6,000, 8,000. If your audiometer allows it, 10, 12, 15, 20, or whatever the numbers are on your audiometer. There's a wealth of information there, and if we're not measuring it, we're not using it. I absolutely agree. I wear bone conduction when I'm out gardening. I wear bone conduction when I'm working on my house or painting or doing things because I want my ear canal open and yet I want to hear my phone calls and whatever Bluetooth music I have been listening to. You're right. Now, the other part about vibrational sound is we don't have good guidance on how much of that will cause damage. The sound levels that you and I talked about earlier from OSHA or NIOSH, those are air conduction, and how that relates to bone conduction, I think is yet to be determined.

Dr. Nina Kraus:

I think that it likely also involves our balance system and our saccule, which is very sensitive to vibration, of course, and the whole somatosensory system. I wonder, because I worry about this when I'm running, is I don't think I'm damaging my cochlea because it doesn't feel very loud. I don't know, it is bone conduction. Maybe it is too loud. I don't want to be damaging my vestibular system either.

Dr. Douglas L. Beck:

Exactly.

Dr. Nina Kraus:

I think we have some homework to do there too.

Dr. Douglas L. Beck:

Absolutely. We know these go hand-in-hand. Franklin published a paper, I want to say it was 2011, maybe 2010. Frank was talking about, as your hearing loss increases into the moderate range, your risk of falls increases times three. I may have that slightly wrong, but that is the idea that yeah, the damage to the vestibular side mirrors the damage to the hearing side. It's a good concern that when you are stimulating bone conduction, is that easier on your hair cells or more difficult? I think we're just at the speculation stage. I want to thank you, Nina. You're always a joy to talk to. You always make me think, you challenge our normative behaviors in very good ways. I think that, that's the only way that we grow and learn. We have to think these things through, set up experiments and find out the answers.

Dr. Nina Kraus:

Again, I think we hear with our ear, we hear with our brain, this is an integrated system. Just as an example, Evelyn Glennie is a deaf musician, a percussionist, and her view on sound and listening, listening. I mean, here is someone who is profoundly deaf teaching me and the world about listening because there is so much listening to be done through our various systems, through our residual hearing, through our vibration system, through our cognitive system. I'm really, really grateful for anything. You all can teach me anything. Your patients can teach me. Doug, it's always a pleasure.

Dr. Douglas L. Beck:

Well, listen, and back at you, but the thing is, we know what we know and more importantly, we should be aware of what we don't know. The way that you acquire new knowledge is by listening. You never acquire knowledge by speaking. Nina, you are a joy to know. I am so appreciative of your time and I want to encourage people if they have not read the book. I think that Of Sound Mind was one of the funnest reads I've ever had in audiology and hearing sciences. Have a wonderful afternoon. I'll look forward to seeing you maybe up in Chicago.

Dr. Nina Kraus:

Thanks, Doug. Thanks so much.

Dr. Douglas L. Beck:

Take good care. Bye-bye.