Become a Creator today!Start creating today - Share your story with the world!
Start for free
00:00:00
00:00:01
Episode 20: Improving medical treatment in hearing loss: Guest Erick Gallun
13 Plays5 years ago
Dr. Erick Gallun joins us today to talk about the latest in audiology research, and how it can be applied to help those with a range of hearing problems. His research has focused on rehabilitation with Veteran's Association (VA) patients. Rapid-response medical care and an understanding of how hearing is affected by brain damage are critical areas in need of research. Advances in portable computing have made widespread assessment possible, and Virtual Reality applications show promise for cost-effective and standardized assessment.
Resources:
P.A.R.T. (Portable Automated Rapid Testing): + link on iTunes
Independent impacts of age and hearing loss on spatial release in a complex auditory environment
by Gallun, et al., 2013
Special Guest: Erick Gallun.
Recommended
Transcript
Introduction to Eric Galwin
00:00:09
Speaker
Hi, welcome to the show. I'm Joe Hardy. And I'm Rolf Nelson. Guest today is Eric Galwin, who works at the Veterans Administration at the National Center for Rehabilitative Auditory Research in Portland, Oregon. He's also an associate professor at the Oregon Health and Science University Department of Otolaryngology. Am I saying that right? That's pretty good, man. That's a tough word.
00:00:39
Speaker
otolaryngology, had a neck surgery and neuroscience graduate program. He's also the editor of a couple journals and is publishing like crazy these days on work in audition and issues that are related to hearing loss and ways to rectify that. So welcome, Eric Gellin, and thanks for joining us today. Great. Thanks for having me. I'm very happy to be here.
00:01:04
Speaker
I always like an opportunity to talk about this stuff with people that I don't normally talk to. I talk to audiologists a lot, and that's useful. But I think that this stuff is more broadly relevant.
Challenges in Veteran Hearing Loss
00:01:20
Speaker
So let's talk about some of the kind of work that you do. So you work primarily with veterans at the Veterans Administration.
00:01:29
Speaker
primarily with hearing loss. So what kind of issues do you run into and what kind of research do you do that is aimed towards helping veterans? Yeah, so it's true that that's where I started out, but the things that we figured out have sort of led me to branch out from that actually. So when I came to,
00:01:58
Speaker
the Portland VA in 2006, we were just beginning to realize what was going on with the wars in Afghanistan and Iraq. And in terms of hearing health care, there was all these people coming back from these conflicts and coming into the audiology clinic with hearing complaints, and they would do their regular clinical testing, basically play
00:02:26
Speaker
pure tones, little beeps as quietly as possible and see what was the quietest beep that you could hear at different frequencies across the whole range of frequencies that are important for speech understanding. So like the same kind of thing that most people might remember doing in elementary school. Exactly, exactly. Just raise your hand when you hear the beep. And these folks were doing fine on that and so
00:02:54
Speaker
the audiologists said, well, you don't actually seem to have a hearing problem. And they said, no, I definitely do. Because when I go into a restaurant, I'm completely overwhelmed. I can't deal with sporting events, like the family conversation, the dinner table, it's just chaos for me. And it didn't used to be that way. And so they came to us and they said, you guys know a little bit about how the brain is involved in hearing.
Advancements in Testing for Hearing Issues
00:03:23
Speaker
maybe think of some tests that you guys could do to see if there's something that we're missing because these folks seem very concerned and they're not very happy that we tell them that there's nothing we can do for them. And so we got a grant from the VA to do some testing using the sorts of tests that are normally done for children with auditory processing disorders.
00:03:52
Speaker
Um, dichotic listening. So you play speech to the two ears and you have them, uh, tell, tell what happened at the two years when there was competing speech, um, gaps and noise tasks. So you play, you play broadband noise and you play little gaps in that, you know, turn it on and off very quickly. And you see what's the shortest gap that they can detect. Um, various, uh, things that are.
00:04:18
Speaker
a little more advanced than just listening to beeps or listening to speech in quiet. And almost immediately we began to see a large number of the folks that we brought in who had been on the battlefield and in particular the people who had had bombs go off near them. They'd been exposed to high intensity blasts. We're doing very poorly on
00:04:47
Speaker
some of these tests. And it wasn't like they were bombing everything. And just to jump in here now, they're doing okay on some of the detection tasks, some of those basic detection tasks. It's not that they can't hear anything. That's right. Okay. And so you're thinking that the ears are probably okay, more or less, but there's something going on in the brain further down in the auditory processing stream. Exactly, exactly. And a lot of these tests were developed by looking at people with
00:05:15
Speaker
brain lesions. So people with strokes or people from the Vietnam era who had penetrating head wounds. So you could actually say for sure, yes, I can see where the bullet trace was and where the bullet track was and yes, this part of your auditory cortex was damaged and people who have that kind of damage do poorly on this kind of complex auditory task. And so we chose our task based on that kind of evidence.
00:05:46
Speaker
And yeah, it sounds it's so interesting, you know, reading your paper, thinking about this to the kinds of injuries that people are experiencing are so different nowadays, or there were more aware of it, perhaps as well, with so many people having closed head injuries where they're, they're not having a bullet in the brain, but they're experiencing trauma from a blast or other, you know, sort of crash type injury.
00:06:14
Speaker
Exactly. And it's just it's very it's it's very topical in the context of the whole concussion thing as well. Exactly. So it really comes out of the amazing technological improvements in terms of both. Protection, so armor and also medical technology, you know, so if you were injured in World War Two,
00:06:43
Speaker
would be two weeks before you got to a hospital with real surgical equipment. If you're injured in Afghanistan, you're in Lansfield, Germany at the major military hospital within 12 hours, maybe six. The same was true during World War I, where they started getting a lot more
00:07:08
Speaker
people with gunshot wounds to the back of the head that ended up surviving because this was after penicillin. Normally, if you get shot in the head and you don't have some sort of antibiotic, you're just dead. But once you get people surviving this and you get a better sense of what kinds of trauma can happen. That's right. All of a sudden, we have people surviving helicopter crashes where they lose
00:07:38
Speaker
both their legs. And so we have had to figure out what this means. And so we had to develop an entire new class of injury, which we call polytrauma, which means that you have major injuries to multiple systems. And the way that we take care of you is very different from somebody who has
00:08:05
Speaker
just one of these injuries. So if you have a major limb amputation and you have a traumatic brain injury, rehabilitation for both of those things now becomes very difficult. Yeah, it's interesting that the kinds of
00:08:27
Speaker
injuries that people think about with hearing and warfare, obviously, is that you're exposed to a lot of loud noises. Yeah, which which is totally true. You know, certainly I have my father in law was in Vietnam and he was exposed to, you know, he worked in a tank, you know, he was a tank commander and a lot of, you know, explosives going off very close to his head.
00:08:52
Speaker
uh, you know, left him with, with very severe permanent, uh, hearing loss. And it even took a long time for the VA to even acknowledge that, that that was what was even happening for just such an obvious case of being exposed to loud noises. You know, and my father as well, you know, his hearing is not so great and he's all, you know, he's in his seventies now. So who knows? It could be normal age related, uh, hearing loss, but he also served in Vietnam.
00:09:17
Speaker
So I think that's what we usually think of when we think of hearing loss, which is absolutely a problem, right? I mean, there's no question. Yeah, no question. That's definitely part of it. So we have, it could be some cumulative loss just through loud noises, like going to a loud concert too much. Yeah. And then I guess, and then Eric, what you're bringing to the table here is
00:09:39
Speaker
Above and beyond that, you've got some trauma to the inside part of the brain that is causing difficulties above and beyond those peripheral losses. You're doing some scanning of these patients and what kinds of damage are you finding? Obviously, I think you mentioned that
00:10:05
Speaker
It's going to be somewhat of a mess because they're not going to be consistent. Everyone's going to be a little bit different than a different sort of trauma. But is there anything that ties this kind of hearing loss where people are having a difficulty in understanding in a more complex environment? So any kind of brain damage that seems to be responsible for this? So the crazy thing is that all of the clinical tools that we have in terms of imaging
00:10:32
Speaker
um, tend to show no
Parallels Between Concussions
00:10:34
Speaker
damage. And so that was one reason that, um, it took so long for people to really start paying attention to this. And, and you know, you mentioned the sports concussion. Well, it actually came out of, you know, the way that I experienced this discussion was we, we started saying, Oh, you know, this is, you know, this, this, these concussions are happening all the time to these people on the battlefield. This is a problem.
00:11:02
Speaker
And then people said, well, but come on, there are so many people that get multiple concussions in sports and they're fine. But wait, maybe, but wait, maybe they're not. And then people started saying, well, wait a minute, have we actually checked to see if they're fine? And then they started checking and they said, oh, my goodness, look at it's just like the battlefield. And so, yeah, it's in both cases.
00:11:32
Speaker
We think that the mechanisms of injury are really on the level of connections between brain areas. It's these long fiber tracts that move the information around among brain areas that are most vulnerable to the movement and to the swelling. So when you have a concussion, often what happens is that there'll be some areas that are
00:12:00
Speaker
that are injured and maybe they'd be okay, but the swelling of that area damages the areas next to it. And then neurons, what they do when they're damaged is they go through programmed cell death. They go through apoptosis. And so in animal models, what you see is that the connectivity among areas is massively decreased about two weeks after the injury.
00:12:27
Speaker
Well, this is a problem clinically because all of our diagnostics are based on what happens at the time of injury and maybe about the 24 hours after. And so if the major effects are taking two weeks to a month to really go through their whole time course, then our clinical diagnosis process may be missing some really important things.
00:12:55
Speaker
Now does it seem does it seem as though. Sorry I'm getting a little feedback here let me just try asking. Does it. Sorry I'm still getting I'm getting just a little feedback from somebody. You want me to.
00:13:22
Speaker
Hello. Hello. Hello. Sounds okay now. Sounds okay. All right. Yeah. Yeah. So. The question that I'd have is.
00:13:34
Speaker
Is there any is there any particularly localized areas that this seems to affect or is it something that just kind of affects so you've got this swelling throughout the brain and it's just kind of causing general tissue damage is there anything particular that seems to be. Important for auditory processing that that reliably gets damaged or is it just I mean I guess when you're talking you're talking about.
00:13:58
Speaker
understanding complex auditory sounds likely taking, you know, being processed in large portions of the brain. So you could imagine that it could be affected by whole brain damage or localized. Is there any indication that it's one or the other? So at this point, we've just had a really hard time pinning this down because the
00:14:26
Speaker
imaging measures that do show some effects tend not to be ones that are used routinely in clinical treatment. So there's diffusion tensor imaging, which is a way of looking at the connectivity among brain areas. But that's a pretty sophisticated technique that doesn't happen in most patient care. And so we've been
00:14:56
Speaker
We've been sounding the alarm about these auditory effects for a while, but haven't really managed to get the attention of the people who are experts in imaging yet. So we're still waiting for a way to really answer some of these questions. I have some ideas. I think that what happens is there's probably widespread damage
00:15:24
Speaker
and depending on the person, you're gonna get damaged in different areas. I thought that the reason that we were seeing so much auditory damage is because those were the tools that we had. We have a hammer, so we found a bunch of nails or things that looked like nails. But I started talking to some of the other folks who work on this and they say, no, actually the auditory injury may be one of the things that is most sensitive
00:15:54
Speaker
to this kind of disconnection. The very precise timing of information is so important for auditory processing that it may be a very good indicator that there's something wrong in the brain. And as we start looking at the memory systems and the visual systems and the balance systems, then we begin to see other things as well.
00:16:17
Speaker
Could you give an example of maybe what it sounds like or what confusion might be like for a veteran with this kind of brain injury? One of the things that they talk about a lot is just the inability to select one voice from among a lot of people talking. So if you're at a busy restaurant,
00:16:40
Speaker
You've got the person that you're trying to talk to across from the table, but you've also got people on the other tables talking, maybe two other people at your table are talking to each other, their dishes clanking, there's music playing, there's kids running by and yelling, and then when the waitress comes by and is ready to take your order,
00:17:04
Speaker
you may have no idea that somebody's trying to talk to you because all the things that you use to sort out that scene are actually pretty low level auditory processing feeding into high level sort of sound source identification, right? So you want to take the information that's hitting your eardrum as a mash and divide it up and
00:17:30
Speaker
turn it into indicators that there are objects in different parts of the world that are making specific sounds. And so the things that we use to do that are temporal correlation. So if a bunch of different things all happen at once, then probably all of those sounds are coming from the same source. If all of the sounds come from the same direction, then they're probably coming from the same source. And so if you have trouble with that timing, now all of a sudden
00:17:59
Speaker
you may not be able to use that cue as well to create a source. If you have trouble with localization of sounds, now all of a sudden it doesn't really sound like things are really coming from distinct places. It sort of sort of blurries. There's something kind of on the left and something kind of on the right, but you can't really tell that there are three things on the left and two things on the right. I was thinking also with this type of coordination intracortically,
00:18:30
Speaker
that, you know, the attentional factors might play a big role as well. So the ability to direct dynamically your attention to different cues and different sources could be affected. It would be interesting to look at, you know, default mode networks versus attentional networks in the resting state, for example. Exactly, exactly. And we really, we feel like there's a lot of
00:18:54
Speaker
really important work that still needs to be done in pulling this stuff apart, right? Because we believe that there is strong interaction between these bottom-up cues of the sort I was just talking about and the top-down attentional and executive function cues or abilities that let you make use of these bottom-up sort of automatic segregation cues.
Interventions and Treatments
00:19:20
Speaker
You know, because sometimes you have to override them. You have to say, well, it sounds like,
00:19:23
Speaker
Yes, those things did happen at the same time, but I know that I was listening to somebody talking about topic X and these things really go with that. So I'm not gonna move it into that stream. And if you, as you say, if you're having trouble with your attentional system, you may make errors on that as well. Okay, so now you've got these people with
00:19:53
Speaker
fundamentally different kind of hearing loss or something that seems a little tricky. What kind of intervention seems to work best? I mean, of course, with a hearing aid, just turning up the volume is really simple, right? But how do you devise something, either a program of training or some kind of hearing aid that can improve understanding for these people?
00:20:20
Speaker
Yeah, so that's a huge, huge problem. We just did a survey. We had 200 VA and civilian audiologists tell us, how often do you see people who have normal pure tone thresholds but still have difficulties hearing and noise? And what do you do for them? How do you do the diagnostics and what kind of rehabilitation?
00:20:47
Speaker
We got a lot of very high, we're still analyzing the data so I can't give you exact numbers, but we got a very high percentage of people saying, yeah, I definitely see people like this. The heterogeneity in terms of what is actually happening on the ground was remarkable. Everybody had a different definition of what auditory processing disorder means. There were as many different diagnostic approaches as I'd ever thought of.
00:21:17
Speaker
Uh, the rehabilitation, you know, there are some people who say, you know, I, I, I fit them with hearing aids, even though they, they don't seem to need them and they love them. There are other people who said, well, I use auditory training games. Um, there are other people who said, well, you know, I just explained to them what's going on. And that really helps a lot and, you know, give them techniques in terms of, you know, avoiding noises, situations, explaining to their family what's happening. Um,
00:21:46
Speaker
So right now, the field is in complete chaos in terms of what exactly we should be doing. And that's because the evidence isn't there. We don't know. It was interesting to me that so many people do find that hearing aids are effective, because you might think, well, it's just going to turn everything up. Why should it help? Yeah, hearing aids are interesting in having
00:22:12
Speaker
warn them myself just in the context of, you know, wanting to experience it and see how they work, you know, being involved in the industry of selling hearing aids for a while. You definitely hear better, even if you don't have a hearing problem with hearing aids, right? I mean, they're remarkable devices. And, you know, the
00:22:39
Speaker
The other that relates to this issue, which is that we taught, and this is true in vision as well, but I feel like it's even more so the case in hearing, which is that we use this threshold approach that if you're below a certain threshold in terms of your hearing, you've got quote unquote hearing loss. And if you're not below that threshold, you don't have hearing loss. You have quote unquote normal hearing, but there's a huge range of hearing sensitivity
00:23:09
Speaker
that falls both within the normal range and then within the quote unquote hearing loss or abnormal range as well. So I think there's a lot of subtlety there. Yeah. And I think that one of the things that I've learned by working with veterans is that a lot of them came into their military service with very, very good sensory abilities. You know, they had spent a lot of time
00:23:36
Speaker
honing their abilities through sports and just the types of people that these days, because we have a volunteer army, these are people that want to do these sorts of tasks. And so I might say, oh, well, you only have 15 dB of hearing loss, and so you're in the normal range. And they say, are you kidding me? I'm really impaired. I can't do the things I used to do. Right.
00:24:06
Speaker
You mentioned in your paper as well that we don't take a baseline of some of these things in the way that you would need to to really know how that's changed over time.
Patient Feedback and Diagnosis
00:24:19
Speaker
Yeah. Yeah. So one of the things that I've learned is that it's very important to pay close attention to what the
00:24:36
Speaker
Uh, patient is telling you, you know, I was trained as a, as a basic, uh, scientist. And, and so, you know, my, my inclination is to believe my instruments. Um, but, uh, when, when the patient tells me, you know, your, your instruments don't line up with my experience, um, it's not that my instruments are wrong, but, uh, it's, it's, it's time to think carefully about what tests I'm doing and the conclusions that I'm drawing.
00:25:05
Speaker
Another thing you've been doing is working on the development and validation of a portable test for Audition. Maybe you can talk a little bit about that.
00:25:29
Speaker
can help to detect maybe trickier to find versions of hearing loss, maybe more of this confusion kind of hearing loss. And you can say a little bit about something about what the tool is designed for. Yeah, that's exactly right. It was through working with these veterans that I realized that one of the big obstacles to providing them the appropriate diagnostics and thus rehabilitation
00:25:59
Speaker
is that the clinical care as it exists right now doesn't include a lot of the basic auditory processing testing that I would do in my laboratory. And as I talk to clinicians about, you know, well, it looks from our, you know, I would tell them about our data and I'd say it looks like you should probably be testing some of these more super threshold abilities.
00:26:27
Speaker
And they would sort of look at me and they're like, yeah, but my audio doesn't do that. And I wasn't trained to do that in school. So, you know, what, how can I do it? You know, and our first approach was, well, we'll use some of these auditory processing tests that have been used for, uh, diagnosing children with auditory processing disorders. But as I looked into those tests, I realized that a large number of them are really tests that were developed, um,
00:26:55
Speaker
by psychologists in the 1970s. And they really are not very clean ways of assessing the system. And we've got a lot of things that work in the laboratory. And so I started teaming up with Aaron Seitz, who's the director of the UC Riverside Brain Game Center, because he explained to me that he had been doing a lot of his vision testing using an iPad.
00:27:22
Speaker
And I said, well, can that really work? Isn't that just kind of a toy? And he said, well, no, think about it. The resolution of that touchscreen monitor and the precision of the timing is way better than the monitor that I use for my dissertation. And I bet the same is true of the auditory output. And I thought about it. And I said, yeah, we had custom-built 16-bit
00:27:48
Speaker
24K sampling rate digital devices in the lab when I was at Berkeley, and we were pretty proud of them. But the iPad does way, way better than that. And so we started building some tools, making use of his expertise at building things for iPads. And the very first test that we did showed that
00:28:15
Speaker
Yeah, we could get auditory outputs that were identical to what we would get in the laboratory from the iPad. At that point, I realized, okay, this is fantastic because not only do I want to get these tools into the hands of clinicians, but I want to get it in the hands of clinical researchers and clinicians who have access to these populations because due to the heterogeneity in these patients,
00:28:44
Speaker
There's no way that I can bring in the 300, 500 patients that I would need to really get strong evidence about what's going on if I had to bring them all into my lab. But if I flip the lab and take the lab to the patients in the form of these iPads and just put the iPads in the hands of all of my clinical research partners and clinicians who are interested and aggregate all the data, now I have some chance of getting the evidence that we need to really
00:29:14
Speaker
drive clinical care forward. And for those listeners who might be interested in seeing what testing is like or playing around with this, is this something that would be available that they could take a look at? Yeah. So we were successful in getting an NIH grant to build this. And so the US government has paid for it. And so as taxpayers or even people
00:29:40
Speaker
who aren't U.S. citizens. This is this is yours. It's free. It's it's on the it's on the App Store. If you go to the UC Riverside Brain Game Center website you can under games there's a one at one of the games is called part. So that's portable auditory rapid testing and the link to to the the the App Store is on there.
00:30:08
Speaker
and also some description of it, and also a link to how to use it. The whole manual is on GitHub as well as some example tests that you can download. Awesome. We can put a link to that in the show notes and if people want to take a look at it. Great. Feel free to email me if you're interested in using it, just checking it out. Also, for students, we found that
00:30:36
Speaker
students who are learning about auditory perception find it much more intuitive to do the test on themselves on the iPad, as opposed to just reading about it. Excellent. Okay. So you've got, Joe, go ahead. I'm sorry. I've been hogging. No, no, no, no worries. No, that's great that you have the test on the iPad.
00:31:00
Speaker
and making it available. Do you think this is something that could be used clinically that will have clinical application in the future? I do, I do. We are in the process of collaborating with a bunch of different clinical research labs to try and figure out what the best tests are to add to what we know about
00:31:29
Speaker
different patient populations and then also hopefully that will help inform rehabilitation. We really think that some of these basic super threshold processing abilities are essential building blocks of auditory perception in the way that I was talking about before in terms of parsing the auditory scene. And so when somebody is having difficulties, if all you know is
00:31:59
Speaker
what the ear is doing, you probably aren't going to be able to make as good a guess as what kind of hearing aid they need and what hearing aid is gonna work best. Yeah, one of the challenges that we've, Rolf and I both have experienced in understanding how, you know,
00:32:24
Speaker
Cognitive rehabilitation works. I'm imagining some of the same problems occur in this auditory processing work is. You know, with the just the sense that the assessments themselves are. Are not as widely used or understood in terms of what they mean for people's everyday lives. It's makes assessment of.
00:32:48
Speaker
efficacy of the training difficult or you know there's a there's a lack of a framework I guess I would say for understanding what's working and not working yeah I would agree with that and especially I think you're getting it out to the transferability of of that's exactly what I was yeah exactly some of these things that that that actually brings up another topic that I definitely was hoping to talk to you guys about
00:33:14
Speaker
We have a grant that we wrote that got some good feedback, and we're going to be rewriting it. But the premise of it is that if we took our testing not only out of the booth, but into virtual reality, that we could actually scale all the way from you're doing a test in a completely gray environment and just hearing sounds to you're doing tests in a simplified environment where you've got little
00:33:44
Speaker
you know, blocks that are making sound, to you're doing a more complicated test where there are faces that are talking to, okay, now you're actually in the restaurant trying to do a complicated task. And let's give you some motivation in the same way that you really would like to successfully order a beer from the waitress. Let's see if we can make you actually want to do well on our tasks as well. And that we think that the VR environment will allow us to do that scaling
00:34:14
Speaker
And so we could do the testing and training in there and we could do the evaluation in a simulated real world environment. Boy, that seems like a perfect application of VR actually. I think that that sounds like it would have a lot of promise behind it, especially for things like localizing. If if one of the problems that you're having, like you say, is issues of timing, then.
00:34:41
Speaker
And as you mentioned before, say you're at a party and you're having trouble associating a particular location with a particular speaker because you're just not getting that timing right because it's so your auditory system so sensitive to tiny amounts of timing difference for localizing. That seems like you could. You could get in a nice immersive environment where people could give.
00:35:07
Speaker
pointing response or some other indication of where they thought something was, and you could really get a sensitive measure of something like this. But also, of course, noisy and more difficult environments to navigate through seems, it just seems ideal for it, I think. You could control for quite a bit. I love it. I want to see what happens. What do you think is going to happen?
00:35:37
Speaker
Um, I think, I think we can, I think we can definitely leverage this because, um, not only do we have, uh, control over everything, right? If you're in the booth and I play, you know, a bunch of people talking, but you look around and you realize that you're actually sitting in a dark booth wearing headphones and there's somebody staring at you through glass, you know, checking to see if you get it right. Like there's a mismatch.
00:36:05
Speaker
and I just, I don't have data on this yet, but I feel that there's a fundamental issue with that mismatch, that it's just going to, you know, some people it's not going to matter, some people it's really going to hurt their performance. And so now you have
00:36:23
Speaker
a big source of error in your measurement that can be taken out by just controlling the visual environment as well. Again, maybe just turning it all gray is sufficient, but I think it'd be better to put uninformative sources in the places where the sounds are supposed to be coming from. Yeah, absolutely. This might be a good time to take a break and we can come back and talk about some additional topics.
00:37:11
Speaker
And we're back. Eric, do you want to talk a little bit about the role that hearing aids play in some of this work? Yeah, yeah. So when I started working on this, I sort of had a very simplistic view of what a hearing aid does. You know, I thought, well, it just, it's an amplifier, right? It's an amplifier that you wear in your ear. And it's kind of amazing that you can, you know, get something that works.
00:37:39
Speaker
But then I started learning more, and I realized it's not just an amplifier. These days, they're all digital. You can't really buy an analog hearing aid anymore, which means that you have a computer processor that's about as powerful as the Pentium 3, except you can wear it inside your ear and power it with a battery the size of an aspirin.
00:38:08
Speaker
things that you can do with this miraculous device.
Modern Hearing Aid Technology
00:38:13
Speaker
And the hearing aid companies have been working very, very hard. And the things that pretty much all modern hearing aids include are noise reduction and directional microphones. And so that means that you're actually getting a sound that's not just louder than it would be normally.
00:38:37
Speaker
but actually has been cleaned up. It's gotten a lot of the background noise taken out. And the directional microphone amplifies what's in front of you and not what's behind you. And so that also helps clean up the auditory scene. Maybe it's the way you want it cleaned up. Maybe it's not. So that's a question of how the hearing aid should be set.
00:39:04
Speaker
but it's something that I didn't appreciate and it might be why people without a need for much amplification still benefit from hearing aids. And you can adjust the directionality as well, right? So if you want a more omnidirectional
00:39:19
Speaker
sound, you can get that if you want something that's directional. For example, if there are different situations, if you're sitting across from someone at a dinner table, that might be one setting where you're getting a very directional kind of sound versus if you're, say, at a concert, you might want a more omnidirectional type of sound. Depending on the listening environment, you might, you can, and some of these devices will adjust automatically.
00:39:46
Speaker
many of them you can adjust manually. So there's a lot going on there. And so you can also filter out for certain frequencies too, I would imagine. Are there some frequencies that tend to be more useful and some that tend to be less useful that might be filtered out? It's hard. So this gets into one of the questions where it would be nice if your hearing aid
00:40:15
Speaker
knew what the environment was and what you were trying to listen for and what task you were trying to do. Because you could you could do some pretty sophisticated signal processing if you knew those things. But in general, because you don't, it's not clear what information should be taken away. Right, so if you're filtering out too many high frequencies and then you got bird watching, you're going to be
00:40:42
Speaker
impaired. And speech, even though most of the energy in speech is in the sort of mid frequencies, the difference between a lot of consonant versus is all in the high frequencies. So by filtering that out, you'd lose quite a bit. And also, yeah, mostly people who have hearing loss have hearing loss in the high frequency range, so you're actually amplifying
00:41:11
Speaker
the high frequency is usually more than the low frequencies. But yeah, I mean, in general, there's probably still more work to be done there in terms of artificial intelligence of understanding the environment. One of the issues that I'm super interested in has to do with brain plasticity, and how it relates to hearing aids. There's the hypothesis that's been put out there and written about a decent amount, which says something along the lines of, if you have
00:41:41
Speaker
hearing loss that affects certain frequencies, you're having less input to the auditory system in your everyday life. And as a consequence, you could have negative plastic processes in the brain. In other words, your brain is adjusting and changing in a negative way, because there's just not that input, that input is not there. And your brain is essentially giving up on that part of the world, if you will. And by
00:42:11
Speaker
giving someone hearing aids, you can actually reintroduce that processing and perhaps stave off some of this negative plastic process and actually maybe even improve someone's cognition over what they would have if they hadn't been wearing them. So not just that the hearing itself is improving things, but that by getting this extra input, you're actually advantaging the brain over time.
00:42:42
Speaker
Is this something that you've thought about at all or do you have thoughts on this topic? Yeah. Yeah. No, I think that's a, that's a really exciting and intriguing hypothesis and parts of it we know are true and parts of it we, I think they're in the process of getting the data. So the thing that we know is true is that, uh, the brain does, uh, have this negative plasticity.
00:43:10
Speaker
You can see this both in looking at imaging and looking at just the amount of brain mass in different areas associated with deprivation. You can basically see with functional imaging, you can see areas that are getting good input
00:43:40
Speaker
taking over areas that are not getting input. And then when you do get input, it's hard for those areas to take back their territory. This is very clearly shown in the cochlear implant literature. So cochlear implants are the only sensory prosthesis that are currently being worn by
00:44:09
Speaker
hundreds of thousands of people very successfully. There's no vision or vestibular or somatosensory prosthesis that works at that level at all and is in such clinical usage. But there's a lot of heterogeneity in terms of how well people do, and one of the most significant factors is length of deprivation. So the sooner you get your cochlear implant, the better you're going to do. And part of that
00:44:44
Speaker
Hello? Hello? Oh, I think you dropped. We lost him. Let's call him back. Add. I think I hit a button. I did too, so maybe we'll call him back. Hello? Now I'm back. Oh, hey. Hey, sorry about that, Eric. We dropped you. Oh, OK.
00:45:12
Speaker
OK, so sorry, let's see where exactly we go. Mm, not too far, just like 30 seconds, OK? So let me see, can we cue you back? We're talking about cochlear implants, cochlear implants. Should I start with the cochlear implant thing again? Sure, yeah, I think that's a good place, sorry.
00:45:42
Speaker
So one area that we know for sure that deprivation matters is cochlear implants. So cochlear implants are the most successful sensory prosthesis that has ever existed. There are hundreds of thousands of people wearing them and some of them are extremely successful. They can talk on the phone with these things.
00:46:05
Speaker
It's basically an electrode that stimulates your auditory nerve directly, which is amazing that it works. If most of your ear is not working, you just get a microphone and plug its output directly into the cochlea where sound is transduced into a neural signal. It's not quite that simple, but you can think of it that way for sure. The cochlea is basically part of the brain.
00:46:33
Speaker
So what happens is the electrical signals actually go, you put the electrode into the cochlea and then the electrical signals go through the bone of the cochlea and stimulate the auditory nerve. So you're making the auditory nerve fire in response to sound. So they're not directly stimulating the cochlea? No, they're directly stimulating the auditory nerve. So you can have a completely dead cochlea.
00:47:01
Speaker
I assumed it meant that you needed to work in cochlea, but that's interesting. Okay. Well, that's. So I'm, I might, I'm totally deaf in my right ear. I had a tumor grow on my auditory nerve and they section the nerve to take out the tumor. So my cochlea might be working, but I don't have an auditory nerve, so I can't have a cochlear implant. So it's, it's an amazing device. And one thing that it's, it's taught us a number of things about
00:47:31
Speaker
just how hearing works. One of the things that it's taught us is about this deprivation question. So we know that people who get their cochlear implants sooner do better. Part of this is just the normal plasticity of children as compared to adults. So if you give a cochlear implant to a baby,
00:47:56
Speaker
they will do better than if you wait until it's a teenager or a young adult. After its brain has already figured out how to organize itself without this auditory input. That's right. But it's also the case that if you take an older adult who has had one ear that's been amplified their whole lives and another ear that has not, and you implant both of them
00:48:23
Speaker
they're much more likely to do well with the ear that has been getting stimulation than the ear that has not. Now, there's often a compound, which is that they haven't been getting amplification in one ear because it's worse ear. But in general, these data are suggestive of this idea that the auditory cortex or other brain areas sort of
00:48:49
Speaker
or take over whatever territory they can. And so if you're not getting input in a particular area, other rain areas say I can use that real estate. The use it or lose it idea. Yeah. OK, so. Alright, so hearing aids seem to work. You mentioned that hearing aids work partially or occasionally on people with the kind of hearing loss that you've been talking about.
00:49:20
Speaker
and we talked just a tad about brain training. I wonder if you have any insights or thoughts about, again, since both Joe and I have worked on brain training stuff before, about what kind of training might be effective or helpful for people with this kind of trauma.
Auditory Training Innovations
00:49:41
Speaker
Funny you should ask. In fact, we have an NIH grant
00:49:46
Speaker
to develop a auditory training game that is also available at the UC Riverside Brain Game Center website. So same link, okay. Yeah, except this time if you go into their games and instead of clicking on the link that says part, you click on the link that says listen. So listen is an auditory training experience. And I won't promise that it works. We are actively
00:50:15
Speaker
improving it right now. So hopefully there'll be a new version that is even better soon, but you can get a sense of what we're working on. We've identified sort of three areas that we think are the most fruitful things to provide training on. One of them is just spatial awareness of sound. So there's part of the game where
00:50:44
Speaker
you have to make discriminations as to whether a sound came from the left or the right. There's also another part of the game that has to do with frequency changes. So you hear these sounds that are either rising or falling in frequency. So they're going whoop or whoo and your job
00:51:04
Speaker
in this game is you're a little wisp, a little dot flying down a dark tunnel, and occasionally these electric barriers come up either horizontally across the tunnel or vertically from between the top and bottom, and you have to move your little wisp either left or right or up or down to avoid getting zapped. And these sounds tell you should you be going up or down, left or right. And so we think that
00:51:33
Speaker
increased awareness of these two dimensions could really help people sort of get their brains doing the sorts of tasks that you need to do to have the building blocks you need to create awareness of sound sources in the environment. And then the third part is an auditory memory task. So you hear these sort of funny sounds
00:51:59
Speaker
in a sequence and there are rings that you can go through and you go through one ring. If you hear the same sound and you go through a different ring, if you hear different sounds, it's basically the NVAC task. So you're not comparing to the sound you just heard, but you're comparing to the sound that you heard two sounds ago. This is a wickedly difficult task. It sounds really simple, but it's really difficult. Aaron can do it. I can't do it.
00:52:31
Speaker
And how far along in progress is a training program? So we have it working. It's available again for free on the App Store. We've done some testing with young normal hearing undergraduates at UC Riverside. And we think we have things working to the point where we can actually see improvement in these abilities over training.
00:53:01
Speaker
maybe a little transfer to some of the tasks that we have in part. But we think that maybe running it on normal hearing undergraduates is not really the best way to see whether or not they work because these folks are all doing quite well with these tasks when they show up. And so this summer one of Aaron's graduate students is going to come up to Portland and we are going to start sending iPads home with people and having them play the game and then
00:53:31
Speaker
see what happens. Cool. How much training do you think you might need to do to see some effects? We see the in-game learning pretty quickly. So I think we'll probably only have these people do maybe five home training sessions. But this will really be more of a test of whether or not we can
00:54:00
Speaker
convince people to play the game and what they think of the game, if we see some learning, great, but this is more usability. So this is an RO3 through the National Institute for Human and Child Development. And so the goal is to get something that we can then use to get a larger grant to do more serious study. But it's been remarkable to me how much work goes into just
00:54:30
Speaker
getting something to the point where you can start to ask the question whether or not you should be doing what you're doing. For real. That's funny. That's really cool, though. Good luck with that project. That's potentially some important work for people who are having these kinds of problems, especially some of our veterans.
00:54:58
Speaker
Yeah, we'll certainly be on the lookout for updates on this too, I think. One of the things that I think is that, you know, honestly, even if we didn't get the brain to change, you know, what territory was doing what, just helping people learn to pay attention to sound might be very helpful. My mom has been doing some volunteering and
00:55:24
Speaker
dance here I are and comes into the lab and sits through our tests and stuff. And I asked her to play the game and, you know, she thought it was pretty interesting. And then we were, we were walking, walking home and she said, you know, I never really thought about the fact that sounds have locations. Like I knew that things have locations, right? That car is over there, but I can't see that car, but I can hear it. And I know where it's coming from.
00:55:54
Speaker
And I think after playing your game, like, I'm just sort of more aware of that. I just hadn't really taken it apart. And so for me, if that's all that we managed to teach people, I think we might still be very beneficial. Absolutely. You know, one of the things that is unquestionably trainable, that kind of pervades a lot of the literature in these types of
00:56:26
Speaker
tasks, but I think is not always appreciated, is just the idea that the dynamic control of attention, so the ability to attend to certain things and not others or certain things preferentially to others, is a skill that is extremely trainable and could potentially be beneficial to be trained. Yeah, yeah.
00:56:49
Speaker
This also it also seems useful in terms of. So imagine if I if I had a hearing loss in this sort of sense, I probably might be. Less likely to go out and be in environments where you're getting this kind of complex noise, so it might be that you're getting some avoidance of situations which might lead to further atrophy or further kinds of problems so.
00:57:18
Speaker
maybe with something like this, you're also getting, you're getting something that people can actively participate in and maybe work on cognitive strategies to, you know, to immerse themselves a little bit more and pay attention in complicated environments too, which might be a good place for recuperation rather than isolating themselves. That's a great point. One of the things that I've learned from the
00:57:46
Speaker
from working with the concussion patients and the concussion doctors is that there's this idea of active rest.
Future of Hearing Enhancement
00:57:53
Speaker
So it used to be that they said, oh, after you get a concussion, you should just sit in a dark, quiet room for two weeks. And that's not true anymore. They said, no, you don't want to do that. It's like after you've
00:58:09
Speaker
broken your leg. You need to get the muscles working again. Don't stress yourself too much as soon as you start to feel like you've got a little bit of a headache or whatever, stop. But you should be doing something. And I think that a lot of people with hearing loss give up and avoid the social situations and
00:58:33
Speaker
You know, Joe was talking about this idea of whether or not cognition can be improved by giving people access to sound. And we know that there are strong correlations between cognition and hearing loss. We don't know what the causes are. It might be that there's some third factor that's causing both.
00:58:57
Speaker
But it would not be crazy to me to think that if you are not putting yourself in these challenging situations, that you just get less used to doing these cognitive tasks and using your brain in these ways. And so finding any way to encourage people to engage with sound and engage with other people, I think would be beneficial. Interesting.
00:59:29
Speaker
Cool, so what are you most excited about in the field right now in terms of where things are going? Whether something you're directly working on or your colleagues are working on? Yeah, so the idea that we can really start using technology to help everybody hear better is very exciting to me. The fact that
00:59:58
Speaker
Bose has come out with a hearing system that is useful for people both with and without hearing loss. It's very exciting to me. The fact that the Apple earbuds are now really
01:00:16
Speaker
beginning to function as assistive devices is exciting. There's a company called Nuheara that has a device that they call IQBuds that are just for helping people have super normal hearing. And I think that there's no reason to think that people with normal thresholds
01:00:42
Speaker
can't do better in complex and noisy environments. And the more control you have over what the sound is that's reaching your ears, the better you're going to do. So I imagine a time when you have very, very small, almost undetectable devices that you can wear in your ears and you take out your phone and you look on the app and it tells you what all the sound sources are around you. And you just go through and you like make this one bigger.
01:01:11
Speaker
kill that one, record this one. That's really cool. That also leads perfectly into the last question, which we have to ask always. I'm thinking how to phrase this. How is this getting phrased?
01:01:29
Speaker
which is how does this lead to the RoboPocalypse? What's the dystopian? What's the relation between hearing and the RoboPocalypse? What does the RoboPocalypse sound like? Maybe, I don't know. Yeah. Well, there are a number of versions of this dystopian future. One of the most obvious ones is that
01:01:59
Speaker
Every device around you has a microphone, and all of the information is being captured and sent to the cloud. And there are machine learning algorithms that are aware of absolutely everything that's happening at all times. Let's not be absurd, Eric. No, that could never happen. We know that multi-microphone arrays
01:02:25
Speaker
tremendously effective. We know the machine learning algorithms are already predicting what you're going to type before you type it. Why, you know, I'm sure they can predict what I'm going to say before I say it. Absolutely. Yeah, I mean, one of the things that related to that is, you know, as you're talking about the smart buds, you know, the IQ buds, you know, there's some, for example, Starkey has come out with
01:02:51
Speaker
artificial intelligence hearing aid that they're touting as being able to translate foreign languages in relatively, you know, real time, which is super cool, right? But that's the positive. The negative is then if that actually works, no one has to learn a foreign language. And I feel like we've lost something really important if and when that happens. Yeah. Yeah. No. And, you know, we've we've already seen some some beginnings of this cognitive decline.
01:03:22
Speaker
If you do a working memory task where you ask somebody to repeat back a string of digits, you will find that there's an age effect, but tragically, it goes in the wrong direction. We're getting worse. The phone number have no idea what you're talking about and have no practice on this task. That's funny.
01:03:51
Speaker
Well, I think that might be a great place to wrap up the conversation as we've discovered the dystopian negative consequence. But I think that the work that you're doing now is awesome and was going to help a lot of people. So, you know, thanks for being on the show. And we really appreciate it. Really fantastic. Thanks a lot, Eric. Great. Great. Thanks for having me on. This was a lot of fun.