Noise-Induced Hearing Disorders

Noise can damage hearing in numerous ways: hearing loss, tinnitus, difficulty hearing in noisy settings, as well as other sound detection or sound processing deficits. In this episode, we talk to Colleen LePrell (UT Dallas School of Behavioral and Brain Sciences) and Odile Clavier (Creare), two editors of the recent Noise-Induced Hearing Disorders Special Issue of JASA. Learn about current clinical and investigational tools for studying noise-induced hearing disorders, as well as the latest on research about noise monitoring and hearing protection. 

Read the Special Issue on Noise-Induced Hearing Disorders: Clinical and Investigational Tools

Read more from The Journal of the Acoustical Society of America (JASA).

Learn more about Acoustical Society of America Publications.

Music Credit: Min 2019 by minwbu from Pixabay. https://pixabay.com/?utm_source=link-attribution&utm_medium=referral&utm_campaign=music&utm_content=1022

Transcript

Kat Setzer  00:06

Welcome to Across Acoustics, the official podcast of the Acoustical Society of America's Publications office. On this podcast, we will highlight research from our four publications. I'm your host, Kat Setzer, Editorial Associate for the ASA.  Today we're highlighting a JASA special issue, the Special Issue on Noise-Induced Hearing Disorders. Joining me today are two of the guest editors for the issue, Colleen LePrell of University of Texas at Dallas and Odile Clavier of Creare. Thank you guys for taking the time to speak with me. How are you? 

Odile Clavier  00:40

Good. 

Colleen LePrell  00:40

Good. Thank you. 

Odile Clavier  00:42

Happy Monday. 

Colleen LePrell  00:43

Happy Monday. 

Kat Setzer

First, can you tell us a bit about your research backgrounds? 

Colleen LePrell 

Sure, happy to. So I'm Colleen LePrell, and my graduate research used psychophysical testing models to understand the acoustic cues that were important in different kinds of communication signals. And then I did a postdoc in auditory pharmacology, and in particular, we were looking at the neurochemistry of the descending pathways that come from the brain out to the ear, the efferent pathways they're called. And those combinations of background really led to a set of studies where we were looking at some of the biochemical events that underlie noise injury. And with the better understanding of things that happened in the ear that lead to cell death and hearing loss, we started working on interventions that would prevent noise injury, and that led to a series of clinical trials looking at different interventions for noise injury in humans. And in my lab now, we're really focused on trying to identify the earliest deficits that occur in people who are exposed to different kinds of noise. And we're very interested in prevention of hearing loss, and that includes drug approaches and device approaches, using hearing protection devices (ear plugs and ear muffs).

Odile Clavier  02:11

Yes, so my name is Odile Clavier and I'm an engineer. I actually was trained as an aerospace engineer and joined a small company called Creare that is located in Hanover, New Hampshire, about 20 years ago, and doing a diversity of technology development at Creare. But over the last 15 years I have ended up specializing in biomedical applications, and especially hearing-related applications. I've developed with my team, we developed a boothless audiometer, called the watts. We've developed a number of devices trying to enable testing closer to where the patient or user is. We're also working on a variety of devices related to noise assessment, whether in the ear or in impulse environments. So that's the kinds of things that I do. I tend to work closely with audiologists and industrial hygienists and other researchers to come up with technologies that fill the gaps.

Kat Setzer  03:19

Very cool. So like the implementation of the research, and that kind of thing. 

Odile Clavier  03:23

Exactly.

Kat Setzer  03:23

So how did this special issue come about?

Colleen LePrell  03:25

Yea, so this special issue was really a direct follow up to a previous special issue in JASA that was published in 2019. And that special issue was focused on the groups that are most at risk for noise injury and might benefit from pharmaceutical interventions, the animal models and the types of laboratory noise exposures that are used to study noise injury and its prevention, and really the many factors that influence individual vulnerability to noise injury.  But more broadly speaking, these special issues, this one and the previous special issue, are a direct effort that comes out of the Hearing Center of Excellence. So the Hearing Center of Excellence, it's part of the United States Department of Defense, and it was legislated by Congress in the 2009 National Defense Authorization Act. And this act was put into place directly in response to the high rate of noise-induced injuries to service members and the high rate of noise-induced disabilities in veterans. And one of the working groups within the Hearing Center for Excellence is called the Pharmaceutical Interventions for Hearing Loss group, or the PIHL group. And both Odile and I have been very active with the PIHL group really since the the formation of this group back in 2010 or so. And the PIHL group broadly invites and includes anybody who's interested from the scientific community, from academia, from industry, from foundations, from organizations; they're really very broadly inclusive of people with diverse expertise. And they have organized five special issues that broadly addressed noise injury, and also chemical ototoxicity, which is injury to the inner ear that's related to either prescription medicines or chemicals that are found in different workplace settings. So the special issues have tried to bring together current information and advance the understanding and hopefully the opportunity for treatments for noise injury to try and ameliorate this really significant problem of noise-induced injury.

Kat Setzer  05:50

Okay, sort of a meeting of the minds but with publishing.

Colleen LePrell  05:54

 Right.

Kat Setzer  05:54

So what are some noise-induced hearing disorders, and how do they arise?

Odile Clavier  05:58

Well, so you know, there's the classic noise-induced hearing loss, where you actually lose some of your ability to hear due to noise exposure. There's also tinnitus, which is the ringing in the ears that can be caused by exposure to noise, and hyperacusis, which is a sensitivity to sounds that are not typically painful to others. So slightly louder sounds can actually hurt some people. And so those are some of the main categories of noise-induced hearing disorder. There's actually, in recent years, there's been a lot of discussion on hearing-in-noise issue related to the ability to understand speech in background noise when you have been exposed to noise before; so this is more related to the ability of the brain to process the sounds such as temporal processing, or even localizing binaural processing, the ability to process the sounds from both ears at the same time, which is affected through damage caused by noise exposure to the ears, without necessarily resulting in hearing loss per se, or tinnitus, or hyperacusis.

Kat Setzer  07:11

Okay, okay, got it. So how does noise lead to these disorders?

Colleen LePrell  07:16

So in the inner ear, there are different kinds of cells. It's an exquisite structure with tiny fragile cells. And there's a particular type of sensory cell called the outer hair cell that we've known for a very long time is responsible for the really exquisite sensitivity of the inner ear, when you think about how they need to transduce sound waves, the miniscule vibrations of air molecules into neural signals. So these outer hair cells are part of that process. They amplify that signal within the ear, and they're highly vulnerable to noise injuries. So when these cells are damaged by noise exposure, thresholds will increase, meaning that quiet sounds that could be heard prior to noise exposure are no longer as easily able to be detected. So sound has to be louder in order to be heard. And in addition, they're very responsible for what we would call frequency resolution, that clean processing of different frequencies so that you can hear all of the different pitches that are captured, that are encompassed in speech and other signals. So sound can be distorted when the outer hair cells are damaged. In addition to the outer hair cells, in 2006, there were some new data that came out of Sharon Kujawa and Charlie Lieberman's lab that showed that the synapses that connect another type of hair cell, the inner hair cell, to the nerve fibers that are responsible for carrying sound to the brain are also really uniquely vulnerable. And damage to these synaptic connections between the hair cells and the nerve are thought to be one of the key causes of noise-induced hearing disorders, such as tinnitus, and hearing in noise. So we have different kinds of cells that are sort of classically attributed with different kinds of functional deficits. And really, labs around the world are trying to more precisely identify possible causal relationships to understand exactly which types of cells are responsible for which types of function within the inner ear.

Kat Setzer  09:35

Okay, that makes sense. So a lot of different places that things could go wrong, and just trying to figure out which ones cause which problems. So who are most impacted by noise-induced hearing disorders?

Odile Clavier  09:46

So a lot of folks in different industries can be impacted. You can imagine in certain manufacturing plants that are noisy, mining industry, construction, and also musicians, professional musicians can, can be impacted by noise-induced hearing loss. And of course, folks in the military, all services are impacted by noise exposure. And individuals who are also exposed to impulse noise moreso than just continuous noise, such as law enforcement agencies where there's a lot of that type of noise in their, in their training or in their environment, can be impacted by noise. Not all of these industries are regulated. A number of them are regulated by OSHA, of course, in the military, there's regulation within the Department of Defense. And, you know, other industries have their own regulations, such as the mining industry, but some of those industries are not regulated, actually. And so it's kind of everyone is on their own.

Kat Setzer  10:46

Yeah. Also, we want those other industries to gain regulations so that... Yeah, ok.

Odile Clavier  10:51

Right, well, and even if there isn't regulation, the employers still want to do the right thing. And then so they need to understand, you know, what the right approach is to protect their employees.

Kat Setzer  11:02

Yeah, that totally makes sense. So tell us about the regulatory pathways for inner ear medicine. Why is the understanding of these pathways important for the investigation of noise-induced hearing disorders?

Colleen LePrell  11:14

Well, I guess the the first thing to remember is that all drug development in the United States is done under the oversight of the Food and Drug Administration, or the FDA, and in other countries, there are equivalent national regulatory agencies that oversee drug development within those countries. And as we think about FDA oversight, the FDA has the major responsibility for approving the methods that are going to be used in clinical trials and the populations that are going to be studied in clinical trials in order to determine if the clinical trial will be likely to provide evidence that is sufficient to warrant medical claims for some type of clinically meaningful benefit. There are many, many different methods that are used in hearing science and hearing research, but not all of these methods are going to be equally useful or equally amenable to clinical trials, because of the FDA'ss emphasis on clinical benefit. So a major goal for this special issue was to inform the scientific community about issues in the selection of clinical trial test measures, because of these major differences between things that are useful in scientific inquiry and things that are useful in drug development. In our scientific studies, we really often try to use tools that provide insights into the specific types of cells that we were talking about previously, into cell health or into synapse survival. But in clinical trials, the emphasis is really on the function, the clinically significant functional outcomes that are going to impact patient quality of life. So we wanted to try and provide material that will help clarify those kinds of differences between lab research and drug-related research.

Kat Setzer  13:30

I see. So let's go more into these focuses of how to measure outcomes of clinical studies. Can you tell us about some of the methods you guys discussed in the special issue?

Odile Clavier  13:41

Sure. So the audiogram is kind of the gold standard for assessing hearing. And it is, however, a fairly coarse measurement of hearing, at least in the way it is typically used in the clinic.

Kat Setzer  13:59

Can you explain what an audiogram is just a little bit for listeners who might not be familiar?

Odile Clavier  14:03

So the audiogram is the is kind of the gold standard hearing test. And it is basically a measurement of the lowest sound that a person can detect. 

Kat Setzer  14:17

Okay, 

Odile Clavier  14:17

So it measures very low-level sounds. It detects, you know, it determines how low of a sound you can hear at different frequencies. 

Kat Setzer  14:29

Okay, got it. Thank you. 

Odile Clavier  14:31

So it's considered a behavioral test, because the person has to respond. And it involves, it's also considered a peripheral test, meaning it's testing the hearing, the peripheral hearing of the person. 

Kat Setzer  14:47

Okay. 

Odile Clavier  14:48

And another area of interest is speech in noise since that is the functional expression, I guess of hearing disorder, not being able to hear speech. Speech in noise is a major complaint of people affected by noise. So being able to measure that is another outcome that would be very useful. However, there's no real consensus currently on what the right speech-in-noise test might be, or even which of the many should be used in clinical trials. And so certainly one of the things that the special issue is trying to do is to kind of summarize what's out there, what's available to do that and under what circumstances it's been used, and how those various speech-in-noise tests, for example, or ways of doing an audiogram, can be used to inform clinical outcomes.

Colleen LePrell  15:40

And that's really the perfect segue to some of the other tests that were talked about in the special issue, because in addition to the audiogram, which, as Odile just explained, is a behavioral test that requires the patient or the participant to provide a subjective report of what they hear, we have other tests that we would call objective, meaning that the patient or participant just sits there and we measure some sort of response that is evoked by sound. And so in the special issue, we also talk about something called otoacoustic emissions, which involve putting a small microphone assembly into the ear canal, and you deliver sound through a little speaker within this microphone assembly, and that sound goes into the ear. And there are essentially distortions and reflections that come back out of the ear as sound travels in and then is reflected back out. And we can measure those distortions that come back out to provide insights into the health of those outer hair cells that are so vulnerable to noise injury, and so important for perception. There are also ways to measure neural evoked potentials. And this, again, is one of the topics that's discussed in this special issue is, how can we use those measurements of neural responses, where we're measuring the voltage as it is processed in different parts of the brain, as the signal is traveling upwards through the brainstem? How can we use these otoacoustic emissions and these evoked potentials to infer the underlying pathology that a patient has to help select participants for clinical trials or to measure the effects of noise on those cells, and whether a drug was able to prevent those cells from being damaged by noise and really uses is looking at part of patient outcomes, looking at better hearing, better hearing in noise, less tinnitus, and the specific changes in hair cells and neural evoked potentials by combining these different measures. So these kinds of studies are the basis of the drug indication, the medical labeling of the drug, and then the understanding of the specific cellular pathology or specific pattern of protection that underlies the protection.  And why this is so important is because different types of drugs have different targets. So there are some drugs that are targeting the hair cells. And there are other drugs that will serve to protect synapses. They do this in lots of different ways. They might do this through antioxidant properties, or through actions at receptors that are sensitive to different kinds of molecules such as calcium or potassium, they might cause something called vasodilation, an expansion of the blood vessels to protect the blood flow and the delivery of oxygen to the cells in the inner ear. And of course, some drugs are going to be focused on prevention of cell death using pre-treatment or treatment shortly after the noise, but prior to the death of the cells. And other drugs that are discussed in this special issue are focused on hearing restoration. And with hearing restoration, you're looking at gene therapy or small molecule therapies to target essentially, the reinitiation of developmental processes in order to drive the formation of new hair cells and new synaptic connections and try and restore function that otherwise has been permanently lost.

Kat Setzer  19:37

So a lot of different things that you could be studying, and what those all need varies.

Colleen LePrell  19:44

Right.

Kat Setzer  19:45

And, Colleen, you already were kind of just discussing this, but why is this such a major focus of research right now?

Odile Clavier  19:50

So there's obviously there's interest in developing diagnostic tools that are precise because of those different targets that Colleen just mentioned, being able to determine, you know, if changes have occurred after taking the medicine. There was also interest in improved diagnostic measurements to understand the nature of their hearing loss so that then you can apply the right medicine to it. And most likely, we're going towards a, in a direction where we're looking at multiple-measure diagnostics. So a combination. There is no one gold, even though the audiogram is the gold standard, there's really not a single test that gives us the answers that we need; it's likely to be a combination of tests. And a lot of these measures are still kind of emerging and in development. And some studies have shown promise in more than one study, for example, the middle ear muscle reflex has been shown in several studies to be sensitive to noise-indced difficulties, you know, after exposure to noise, not necessarily noise-induced hearing loss. But those various studies use different parameters. And their outcomes are slightly different because of those different parameters. So there's still a need to come to a consensus on, you know, how to administer the test, so that it can be eventually translated into a clinical measure, and a tool that can be approved and accepted by the FDA as outcome measures.  The same thing applies to speech-in-noise tests. There are many, many speech-in-noise tests out there. You know, one example is the triple digit test, which has been used all over the world in many different languages. But even within a single institution, you'll find that there are publications of that test with very different parameters, you know, different types of noise used as the background, different ways to change the signal-to-noise ratio of the targets, to the digits, versus the noise. And all of these end up giving slightly different results, depending on the population you're testing. And so, you know, again, we need to be able to come to consensus on specific parameters for given tests that will be useful for some of these targets that Colleen mentioned. And so part of the goal of this special issue is to encourage research in that direction. 

Kat Setzer  22:26

So creating more of a standardization, essentially

Odile Clavier  22:29

Yes, and exactly. And having, you know, the ability to replicate studies, you know, once there is a particular test, it looks like a possibility, you know, being able to replicate with the same parameters, again, because that is going to be necessary for approval, FDA approval to, for the FDA to accept these tests as clinical outcomes.

Colleen LePrell  22:54

And you know, I can't stress enough the importance of some of the things that Odile has brought up. If you look within evoked potentials, there are three different kinds of neural evoked potential tests that are being used in scientific studies. Right now, there's sort of our classic auditory brainstem response, there's the middle ear muscle reflex that Odile just mentioned, and then there's something called the frequency following response. All of these are different ways of measuring the neural response in the brain that's being elicited by sound. But different kinds of sounds are used, different timing, different frequencies, we're measuring the brainstem activity from different regions within the brain, and there's no clear consensus on which of the tests is going to be the most sensitive, or what protocols should be used for the specific tests. If we look at something like otoacoustic emissions, even with these, they've been in widespread clinical use since the 1990s. But there are many different protocols across clinics and across research studies. And we don't have a single agreed on definition for clinically significant changes in otoacoustic emissions. And we can't directly image the cells in the inner ear. They're just too small to be able to look at them in humans. And so we have to use things like otoacoustic emissions and evoked potential tests to infer the underlying pathology. But we really need better knowledge of what protocols should be used and better agreement so that we're all measuring things in the same way and can compare outcomes across studies.

Odile Clavier  24:44

One thing to add here is that one reason the audiogram is such a beloved test by audiologists is that, you know, it doesn't matter where you're measuring it, who's measuring it, what device you're using, you're using to measure it. It's just the same measurement; it's very standardized. And so, you know, this is one reason that audiogram is here to stay because it is, you know, no matter what device you use, it's the same answer, more or less, within certain repeatability. It's not true with otoacoustic emissions or evoked potentials; there is some dependency on the device and the protocol that you use. And so that's, you know, we need to get to that point where those are just as gold standard as the audiogram.

Kat Setzer  25:30

Yeah, so for lack of a better term, the audiogram is foolproof, essentially.

Colleen LePrell  25:37

You know, it's, it's really interesting that even within the audiogram, while the audiogram is being collected in the same way, because it is such a standardized, repeatable measure, if you look at how people define significant change within the audiogram, it's still varies incredibly from study to study. If you do a review of all of the clinical trials that are out there on different auditory investigational drugs, for auditory indications, there's very different definitions of audiometric change across the clinical trials. So even with our very, very heavily standard audiogram, we've got room for improvement in how we define study endpoints.

Kat Setzer  26:22

That's really interesting. So what were some major takeaway messages regarding diagnostic methods in this issue?

Odile Clavier  26:27

Yes, I think one of the key messages hopefully that comes out of the issue is that one, there are a lot of tests out there and a lot of very encouraging directions that we can go in terms of measurement and being more precise, and more targeted  in what we assess in terms of auditory function, but we need to start focusing on a set and standardizing several diagnostic measures so that we can be more precise and repeatable.

Colleen LePrell  27:00

And I would just add to that another take home is that not every measure that's used in basic scientific inquiry is appropriate for use as a clinical trial endpoint. So we have to be thoughtful in how we're approaching research and clinical trials.

Kat Setzer  27:19

That makes sense. So the other aspect of noise-induced hearing disorders discussed in the issue had to do with the monitoring of noise. How do you measure noise exposure?

Odile Clavier  27:27

Typically, noise exposure is measured using what's called a dosimeter. So noise exposure is really a combination of the level of the noise, how loud it is, and how long you're exposed to that loud noise. So being exposed to very loud noise for a few minutes doesn't have the same impact on your ears as being exposed to maybe slightly less loud noise, but for many hours. So it's the concept of dose that is important. And the other piece is understanding how much of that dose you need before it results in damage to the ear. So the concept of damage risk criteria comes out: understanding the relationship between noise dose and your damage.

Kat Setzer  28:16

What were some notable takeaways about noise monitoring in the special issue?

Odile Clavier  28:20

So one of the key papers in the issue relates to measuring impulse noise, which is definitely an area of research, of research right now. Impulse noise is a is a little different from ambient or continuous noise in that it has temporal characteristics that can make it difficult to measure because it's, you know, very fast rise time and also very high levels. And so there's a need  for microphones that can measure that. In addition, the sample rate, how fast you sample the measurement is important. And so right now, there are no easy devices out there to measure impulse noise, but there is in the research indication that impulse noise can cause hearing damage that is different from long-term exposure to continuous noise. And so it's very important to understand better that exposure to impulse noise and to have an accurate measurement of it.

Kat Setzer  29:17

Okay, so basically, like a gunshot is going to be different than a musician who's in concert for hours.

Odile Clavier  29:23

Exactly, exactly. And, and even if it's the same amount of energy, it may have a different impact on the structures of the ear. In addition, there's also a need to understand the individual dose. So even though two people may be exposed to the general, the same general environment, one person may be experiencing a higher dose, maybe because their hearing protection is not fitting very well or maybe because they're oriented differently. And so there is also interest in better understanding  those issues. And in fact, finally, when it comes to the measurement of noise, let's not forget the measurement of noise during an assessment. So it's a little, a little different than measuring exposure. But when you're doing an audiogram, it's really important to ensure that the ambient noise is at a low enough level, that we're not masking the measurement, the threshold measurement in the person. And especially in the case of clinical trials, where you may not necessarily be doing an assessment in a sound booth, but rather in a different setting, maybe it's in a clinical environment in a, or at the person's work location using say, boothless audiometry, then it really becomes really important to understand the ambient noise, and to report what the ambient noise is during the measurement. So we touched on that a little bit in the special issue as well. 

Kat Setzer  30:53

So what did researchers in the special issue have to say about hearing production to prevent noise-induced hearing disorders?

Colleen LePrell  30:59

So building on this idea that measuring noise behind HPDs is important, there were really two approaches that came out in the special issue. And I think they both have a place and they're both really important. One of these is fit testing, and fit testing is when you actually measure and document how much attenuation somebody is getting from the hearing protection that they've been given. And you can combine fit testing with training. So if they don't get enough attenuation when you do the fit testing, you can retrain them on how to more effectively insert their hearing protection. And you can redo the fit testing until the worker is getting enough attenuation from their hearing protector to keep them safe when they're in a noisy environment.  The other strategy that came out in the special issue is in-ear dosimetry, which is when you're measuring how much sound is present behind the hearing protector throughout the entire work shift. And this gets at the idea that even if somebody knows how to put their hearing protection in correctly, that they may not keep it inserted correctly throughout the entire workshift. It might partially come out; they may intentionally partially remove it in order to hear workplace alarms or to communicate with others. And so if we're doing clinical trials with people who are exposed to workplace noise and are wearing hearing protection, this is a really important potential confound in the study because not every employee who's enrolled in the clinical trial will necessarily be getting this same noise exposure, and therefore the effects of the drug could differ based on how effectively somebody is or isn't wearing their hearing protection. For obvious ethical reasons, people who are enrolled in clinical trials have to be provided with all of the standard protections for their hearing. We couldn't give somebody a placebo to measure how well the drug works and just let them be exposed to occupational noise. So we have to have more effective ways of understanding noise exposure behind HPDs if we're going to try and evaluate how well a drug does or does not work in these populations of at-risk individuals.

Kat Setzer  33:36

Absolutely. That totally makes sense. Do you have any additional thoughts you'd like to share?

Colleen LePrell  33:41

I guess I would just like to stress how much I think this is a really exciting time for hearing loss prevention, that not only do we have improvements in devices that are coming out with more specialty HPDs for different populations, electronic HPDs, HPDs that are trying to preserve music quality, not only do we have better devices, we have more interest than ever and more investments than ever in the development of investigational inner ear medicines. There's more than 40 companies around the world that are working to develop potential medicines for the inner ear. And there are major pharmaceutical companies that have started getting involved in this space. Whereas for many, many years, you know, it was really just small startup companies because there wasn't an existing model for trying to develop and pursue these kinds of products. So I think it's a really exciting time.  And I have in the past always had to either begin or end with a reminder that there's nothing approved by the FDA right now for hearing loss prevention, and I don't have to say that this time because there is actually one drug that has been approved for hearing loss prevention indication. And this is a drug that was approved in September of 2022, for prevention of cisplatin induced hearing loss in the narrow pediatric population. But I think it's incredibly exciting that we've seen the first drug make it through the regulatory process, and with the very large number of things that are being evaluated and the active clinical trial space, I have very high hopes that there will be more in the future

Kat Setzer  35:39

That is very exciting. Odile?

Odile Clavier  35:40

Well, as an engineer, I look at it, as you know, this is a very exciting time to be working in this space. And there's a huge amount of work to be done from the engineering perspective in developing the diagnostic tools and perfecting these tools, improving the precision, the repeatability, and the availability of these tools. So that, you know, these fancy research devices that people are using in their studies can be made available to clinicians, and can be considered valid for clinical trials. So it's a very exciting time to be doing technology development right now. And the special issue pretty much spells out all the different areas we have to work in.

Kat Setzer  36:26

Yeah, it sounds like a very rewarding area of research right now.

Odile Clavier  36:29

Oh, it is and also, because we're also discovering, you know, the impact of noise-induced hearing loss on people's lives. You know, very, now a lot of people have heard that noise-induced hearing loss and dementia have been linked. And so there's a, you know, there's a huge emphasis on the impact of noise-induced hearing loss or hearing loss in general. And so, you know, there's, this is definitely an area of growth from a technology standpoint, as much as from a drug development standpoint.

Kat Setzer  37:01

Yeah, that is absolutely fascinating.  So thank you again for taking the time to chat with me today. You really helped explain some of the impacts of noise on hearing and how we can better study these disorders and how we can reduce or prevent hearing damage from noise. For listeners who are interested in learning more, we'll link to the special issue in our show notes and I can also link to this Noise-Induced Hearing Loss special issue from 2019. Have a great day. 

Odile Clavier  37:23

Thank you. 

Colleen LePrell  37:24

Thank you. 

Kat Setzer  37:25

Thank you for tuning into Across Acoustics. If you'd like to hear more interviews from our authoors about their research, please subscribe and find us on your preferred podcast platform.