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From the Front Row: Hearing loss as a public health issue

Published on January 7, 2022

 

This episode’s guest is Dr. Bruce Gantz, University of Iowa professor of otolaryngology and internationally recognized expert in cochlear implants. He talks with our crew about hearing loss as a public health issue, how it affects quality of life, and how COVID-19 has increased the number of patients seeking access to hearing aids and implants.

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Ben Sindt:

Hello, everyone. Welcome back to From The Front Row, brought to you by the University of Iowa College of Public Health. My name is Ben Sindt, and I’m joined today by Alexis Clark. And if this is your first time with us, welcome. We’re a student-run podcast that talks about major issues in public health and how they’re relevant to anyone, both in and out of the field of public health. Today, we’ll be chatting with Dr. Bruce Gantz, head and neck surgery department and faculty at otolaryngology and neurosurgery here at the University of Iowa hospitals and clinics. Dr. Gantz is recognized internationally as a leader of cochlear implant technology. Welcome to the show, Dr. Gantz.

Bruce Gantz:

Well, thank you, Ben and Alexis. Thank you for having me on.

Alexis Clark:

So before we get started, could you, briefly, explain what exactly otolaryngology is, and how did you initially get introduced to this specialty and what made you decide to pursue a career in it?

Bruce Gantz:

Okay, well, otolaryngology head and neck surgery is ENT — ears, nose, and throat. And so we are a surgical subspecialty of surgery, and actually, otolaryngology is very interesting in that we do our own medical and surgical management of patients because we don’t have a medical component like, let’s say, cardiology, feeding patients to cardiac surgeons, or internal medicine sending patients to general surgeons. So we take care of a really broad patient population, from infants and newborns to the elderly. And so it is a very rewarding specialty. It has to deal with the senses, hearing, balance, sense of smell, sense of taste, and swallowing, and a lot of other kinds of things that are very important to the quality of life for patients. And so it’s very rewarding.

Bruce Gantz:

So how did I get interested in it? Well, when I was an undergraduate, I did a research project with a program in speech and hearing. I took that because I was sort of interested in it. I don’t know why I had an interest, but I did. I got engaged in research in cleft palate and cleft lip and then found out that the way to go about that, at least at the university, was in otolaryngology head and neck surgery because we cared for patients with cleft lip and cleft palate. I migrated away from that because I became very interested in the ear, hearing, and balance and tumors of the skull base. And I did a residency here at the university, after graduating from the university, and then went on and did a fellowship in Zurich, Switzerland, with an individual that was really innovative in skull-based surgery, so that’s how I got here.

Ben Sindt:

Awesome. So before we get too deep into this, could you start off, what is a cochlear implant and why are they so beneficial.

Bruce Gantz:

Okay, well, can I talk a little bit about hearing loss, in general?

Ben Sindt:

Yeah, of course.

Bruce Gantz:

So we have people that develop hearing loss from birth or congenital. We have progressive hearing loss, and we have people that have hearing loss due to parts of the ear that don’t function very well, like the ear drum or the middle ear bones. And so we have either congenital or acquired. Most acquired hearing loss is genetic, meaning that it runs in families. And so people can be born with normal hearing and then, over a period of 30 to 40 years, gradually begin to lose it. We know that hearing loss occurs in the high frequencies, usually as we age, and causes people to have a lot of word and understanding problem. A bigger problem, a public health problem in Iowa is noise, and noise is regulated now in the factories, but it’s not regulated on the farm. And so I have a lot of farmers and people that work on farms that come and have significant high frequency hearing loss due to noise exposure, but you can have other diseases and disorders that cause hearing loss.

Bruce Gantz:

And most of the time, when people start to recognize they don’t hear as well, for the most part, they think that things are muddled. And most of that is because they lose high-frequency hearing. And the high-frequency hearing is where you hear the Ss and the Ts and the Zs and the Ds, so all the consonants. And so when you don’t have good high-frequency hearing, you get confused and you start to withdraw. And that’s a big issue with people that are older people or people that work in noisy environments that they just don’t want to participate because they can’t communicate very well. So we try to manage hearing loss, first, with hearing aids. And hearing aids are amplifiers, like what you have in your ears, and they turn up the volume, but they don’t clarify the speech.

Bruce Gantz:

So if you have high-frequency hearing loss significant enough to not be able to hear on the telephone, then we start thinking about something that is more advanced, and that’s a cochlear implant. And so what a cochlear implant does is it actually goes into the inner ear. It’s a small, little wire. It’s about 0.4 millimeters in diameter and up to about 0.8 millimeters in diameter. And it goes into the inner ear about anywhere from 20 to 30 millimeters. The inner ear is about 36 millimeters. It’s coiled, and it’s like a piano. And so the hearing organ, the inner ear, is actually a band pass filter, so it separates different frequencies. When I’m speaking or you’re speaking, it’s complex frequencies. And so what it does is it goes through the inner ear and it separates the individual frequencies because each region of the cochlea has a certain dynamic that allows it to respond to a certain frequency, sends the information to the brain. The brain puts it together. So that’s what we call neurosensory hearing loss. In the past, people called that nerve deafness, but it’s really a problem of loss of the sensory cells, which are the hair cells in the inner ear that respond to the acoustic wave that’s set up and then stimulates the nerves.

Bruce Gantz:

The other type of hearing loss is conductive, which is the eardrum, the ear canal, or the middle ear bones. Many times, we can try and repair conductive hearing losses, where we can’t treat neurosensory hearing losses other than with cochlear implants. So the cochlear implant goes in the inner ear. It has a microphone that sends the information through the skin, and it’s not a direct connect, but it is a radio frequency wave. It’s picked up by a small, little receiver that’s implanted under the skin. And then it has a microchip that actually separates the frequencies to the different electrodes. And so you can have 12 to 22 electrodes on these multi-channel cochlear implants, and it allows you to separate the frequency information. And it’s really interesting that we have about 30,000 hair cells in the inner ear that actually do the work to separate the different frequencies. And you can actually have a 22 or 14 or a 16-channel cochlear implant deliver the same kind of information and the brain can respond to it. So it’s really the brain’s ability to make sense. It’s like you know how to speak English. If you went to Russia, you’d have a hard time for a few months until you learned to speak Russian. And so the brain has that ability to be quite flexible and understand words and listen to music.

Alexis Clark:

That’s wild. I guess I did not realize everything that our ear is constantly doing. So, through your perspective, as an otolaryngologist, what are the major public health concerns that you’re seeing now today?

Bruce Gantz:

Well, I think one of the things is noise in the environment and regulation of noise in the farm population, in the workers. We know that you can be in 80 decibels of noise or sound for eight hours very comfortably. Every five DB, you increase that, you have to have the amount of time that you can be in the noise without it causing damage. And so that’s why OSHA regulates the environment in large plants where there’s noise and they require people to wear earmuffs or earplugs to protect them in noisy environments. And what the noise does, it actually destroys those hair cells that separate the various frequencies because they exhaust their energy. And if you look at some animal experiments, where you put loud noise in animals and these hair cells are sitting up there like this when they’re normal and, all of a sudden, they just fall over and eventually die off because they’ve expended all their energy and can’t handle it. So noise is a big thing.

Bruce Gantz:

The other thing that I think people are just recognizing, which is really important, is that hearing loss creates an issue for people to withdraw because they don’t communicate very well. And I will tell you, during this COVID period, we’ve had more people come into us seeking cochlear implants because when you have a mask on and you’re talking, you can’t read lips, and everybody reads lips. And even you two are reading lips, even though you’ve got normal hearing. Hopefully, you haven’t listened to a lot of loud music, but… So when you have this hearing loss, you don’t participate. And I have spouses that come with a patient and say they don’t go to church anymore. They don’t go to the social. They can’t understand the minister. They cannot participate afterwards.

Bruce Gantz:

And so when you withdraw, we know that it impairs your cognition. And so people that have significant hearing loss that were born with hearing have a real problem with cognitive functioning. And so we know that recently The Lancet, which is a medical journal published in Britain, did an evaluation of dementia and Alzheimer’s combination. And they found that one of the most significant factors that you could influence was your hearing. And so about 9% of the causes of dementia is related to hearing. And you might alter 9% of the population if you kept them hearing with hearing aids or with cochlear implants. So I think that’s a huge public health issue that needs to be addressed in the future.

Ben Sindt:

That’s great. So you’ve completed that fellowship internationally back in the day. You talked a lot about OSHA and farms in Iowa. Is there any global mindset that maybe people need to take focus on?

Bruce Gantz:

Well, I will tell you that, in Europe, where I was in Zurich, most healthcare systems are public. There’s not this public-private kind of insurance as sophisticated as it is in the United States. And they all pay for hearing aids and pay for cochlear implants. So they’re much ahead of us in the United States in that regards, but this is a universal problem in developing countries that are unregulated with noise exposure. And in factories, people are suffering much more probably than in the United States. It was interesting that when I was in Europe, one of the things that I was able to do, during that year fellowship, was travel to many countries and actually look at what was going on. This was during the evolution of cochlear implants. I went to France and to Paris, and they were developing a cochlear implant. There was one that was being developed in Vienna. There was one that was being developed in Germany and one in England. And so I was able to travel to these clinics, learn a lot about the different developments, and actually, at that time, the FDA did not control cochlear implants. I brought four cochlear implants home in my suitcase and was able to sterilize them and put them in patients because they were more advanced than what we had here in the United States.

Bruce Gantz:

And then I was able to go to Australia. Someone came to our clinic and asked us if we were interested in learning about a new implant from Australia, and this was in 1983. And I went to Australia and we brought back the what’s now the Cochlear Corporation Nucleus Cochlear Implant, which has the greatest number of implantees in the world. But we were the first center to implant that device outside of Melbourne, Australia. They had done about 15 patients when we went there in 1983. And we started implanting here that device in May of 1983.

Alexis Clark:

So thinking back to when you traveled back to the United States with this contraption that had not been yet used in the US, how you face those skeptics?

Bruce Gantz:

Oh, well, that’s a whole different ballgame because cochlear implants, initially, had a pretty rough start. And, first of all, scientists back in the late ’60s said this couldn’t work. And Millhouse was a visionary and a neurotologist in Los Angeles. And he developed the first single-channel cochlear implant that was actually implanted in a patient that was successful and then went on to commercialize it. But at that time, scientists said it wouldn’t work because it was single channel. And actually, the single-channel devices that went in really didn’t improve word understanding. They helped you with lip reading, but not clarification of words. The multichannel systems, where they had eight to 22 channels now, separated the information and enabled the brain to really use it. So when we started doing this, the deaf population and deaf culture was adamantly opposed to us intervening because we were really changing their whole culture.

Bruce Gantz:

And you have to understand that most children are born to hearing families. 90% of deaf children are born in hearing families. And so most parents wanted to do something else other than signing for their children. And you have to realize that signing has a real limitation in language development and reading. The American Sign Language has an alphabet that is directed at concepts rather than the English alphabet. The association of sign language and reading was really far apart. And the average deaf person that’s an adult that only about, I think, it’s less than 15% have a fourth grade reading level because of the fact that sign language does not translate to words on the page. And so there’s a real dissociation between American sign language and reading. So people understood that, and when we started implanting children, in the 1980s, these children started learning language and speaking like you and I do. It was amazing. We were the first center to actually implant a multichannel device in a congenitally deaf child in 1987 in the United States. And it may be the first one that was congenially deaf in the world. He went on and graduated from the University of Iowa, and he is an engineer. And he also played in the Hawkeye Marching Band, which was really amazing to us because the electrical processing doesn’t do as well with music, especially melody, as it does with words.

Bruce Gantz:

We had the deaf culture that eventually that has not been a problem. I went to a meeting one time in Paris where a bunch of deaf culture people came in and started blowing whistles. They couldn’t hear it, but they disrupted our meeting because they just kept blowing whistles. And then they had to get the police to take them out of the meeting. So that’s how, I think, frustrated the deaf culture was with our intervention that was going to disrupt their population of people, and that has happened.

Ben Sindt:

So, in this past year, you actually performed one of the world’s first robot-assisted electrode implant of the cochlear implant into a patient. So having said that, how did we get there? What challenges did we face? What does it look like?

Bruce Gantz:

Well, so let me step back a little bit and explain why we need to be as gentle as possible in the inner ear. So the inner ear has a thin lining called an endosteum on the inside, and it has a periosteum on the outside. And the endosteum is very reactive to injury. And the reason is that, in the animal world, if the animal gets an ear infection, it can go to a meningitis and kill the animal very quickly. So, as we’ve evolved, if there is an infection in the inner ear, the inner ear responds very rapidly, fibrosis, and closes itself off from the brain because there is connection between the brain and the ear.

Bruce Gantz:

So we have also pioneered a concept of the hybrid hearing. So when we started implanting cochlear implants, we implanted them in patients that were so profoundly deaf, they couldn’t hear themselves speak. And as we’ve learned more and more, we know that we can put them in patients that have some residual hearing in the low frequencies and they perform better. And, in fact, they do much, much better in noise. So a standard cochlear implant is a little bit like the hearing aid. When you get a noise, it really drowns it out. If you have some low-frequency hearing left, you can separate the vocal cords moving back and forth, it’s called the fundamental frequency, from the ambient noise, and it helps you understand speech. So when we’re putting the electrodes in, we found that you couldn’t go very far in because, as the ear turns, the electrode sort of rubs up against the louder outer wall and can injure that endosteum. And when that happens, we have some fibrosis and we lose some of that residual hearing.

Bruce Gantz:

So Marlon Hansen and Chris Kauffman, Chris was a resident with us. Marlon was a faculty member with us. And they started developing a system that could put the electrode in the inner ear more carefully than the hand can, because it’s very difficult to control the hand and slide this little electrode. Even though we think we’re doing it very cautiously, the forces that we’re generating and stopping and starting can injure that inner ear. So this device now can put in the device as slowly as one-tenth of a millimeter per second, and you can hardly see it move. And when they did experiments, they found in animals that when they put the electrode in very slowly, you reduce the forces on the ladder wall and reduce the injury. And so that’s the whole reason for the robot is to help us put these devices in patients that have preserved residual hearing. And also, for people that are not very facile and do a lot of implants like we do, it helps them steady and make the implantation to preserve some structure in the inner ear better. So that’s the whole point of it.

Bruce Gantz:

And this is a disposable robot, and we’ve now got FDA approval, which is really important that we went through this whole process, we created a company at the university, which is called [inaudible 00:23:54] Motion. It’s a spinoff company, and if it’s successful, it will help fund the research in the future and will help the department and the researchers that developed it.

Alexis Clark:

So transitioning now to more of a public health mindset, as those students that are listening to the podcast enter the workforce, do you have any advice for them to help the rising concern of hearing loss among the different communities?

Bruce Gantz:

Yes. I think they just need to be aware of it. And I think the government is going to be more aware of it. Hearing aids are very expensive for many individuals. Congress just passed a law in the last few years to allow over-the-counter selling of hearing aids, which will dramatically reduce the cost. So a couple of hearing aids are between $4,000 and $7,000 for two. That’s a lot of money for people. And if you could get them a lot cheaper for a few hundred and make certain that we can program them very easily remotely, even using your phone, and so as those kinds of technologies become available, we’ll be able to reach more people with hearing loss. I think as people that are interested in public health, this is a huge public health problem. It’s not a life or death problem, but it’s a huge everyday satisfier. And I think just being aware of what hearing loss can eventually lead to, I think it’s really important that we bring it out into the public and make them aware.

Ben Sindt:

So throughout your career, what’s one thing you thought you really knew, but maybe later on figured out you were wrong?

Bruce Gantz:

There are too many. I saw that question. I said, “Man, I don’t know if I can answer that.” There’s nothing that has stuck out that… There’s so many things that happen on a daily basis that I thought I knew, and then I had to go to the internet to find out if I really know it. And as we get older, you need more of that.

Alexis Clark:

Yeah. I think that so many times, you’re going through life and you go through academia, all of this training, and you think you’re ready and then you realize you’re ready in some ways, but you’re always learning in others.

Bruce Gantz:

Well, I think the most important thing is that you don’t be too close-minded about things and really try to be inclusive and not be exclusive and team players. I mean, we do better when we are in teams rather than individuals making decisions sometimes. Sometimes that can get hard too, but I think you need to keep your options open. Our cochlear implant research that we’ve been doing here for 36 years, we’ve been funded by the NIH. This is a whole team of people, including one of your own from the College of Public Health. And we have a statistician that worked with us for a number of years, and he’s on our grant all the time telling us what’s right and what’s wrong and what we can do and how many patients we need to answer this question or that question. So it is multidisciplinary. We have somebody from the school of music, somebody from psychology, and the liberal arts. We have somebody, a neurologist, working with us from Newcastle, England, that we Zoom every other week with or weekly and his team to keep engaged in the research. So you have to keep your mind open and always be appreciative of others and what their thoughts are.

Alexis Clark:

Absolutely. Well, I think that is a great place to close off. Dr. Gantz, thank you so much for coming on From the Front Row. We really enjoyed having you, and I learned a lot and I’m sure our listeners have learned a lot.

Bruce Gantz:

Well, thank you very much, Alexis and Ben. Thank you for doing this, and it’s a real public service in the College of Public Health.

Alexis Clark:

That’s it for our episode this week. Big thanks to Dr. Gantz for coming on with us today. This episode was co-hosted and written by Ben Sindt and Alexis Clark, edited and produced by Alexis Clark. You can learn more about the University of Iowa College of Public Health on Facebook. Our podcast is available on Spotify, Apple Podcasts, and SoundCloud. If you enjoyed this episode and would like to help support the podcast, please share it with your colleagues. Our team can be reached at cph-gradambassador@uowa.edu. This episode was brought to you by the University of Iowa College of Public Health. Stay happy, stay healthy, and keep learning.