Breakthroughs in Tinnitus Management with Dr. Grant Searchfield

Unlock the secrets of tinnitus with renowned experts Dr. Douglas Beck and Dr. Grant Searchfeld in this enlightening episode. Discover the latest research on the spatial perception of tinnitus and learn groundbreaking guidelines for reporting tinnitus location. Dr. Searchfeld, a leading figure in audiology, also shares his rich academic journey and discusses the cultural heritage of the Maori people in New Zealand, adding a unique cultural dimension to our conversation.

We explore the vital role of spatial hearing in survival, highlighting how humans and animals use auditory cues to detect threats. Dive into the complexities of tinnitus, where the inability to locate the sound source can heighten anxiety. This episode provides valuable insights into how principles such as interaural loudness and timing differences can improve tinnitus diagnosis and treatment. Personalized approaches to tinnitus management are emphasized, with practical tips on selecting appropriate masking sounds tailored to individual needs.

Advancements in tinnitus treatment take center stage as we discuss long-term strategies that empower individuals to manage stressful environments. Hear about innovative methods like structured digital therapeutic training and cognitive-behavioral techniques. The episode wraps up with a focus on the importance of a multidisciplinary approach, including audiological assessments and cognitive health management. Don’t miss this compelling discussion that bridges audiology, cognitive health, and innovative tinnitus management strategies.

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Transcript

Speaker 1: 0:19

Thank you partners. Redux faster, drier, smarter, verified Cycle built for the entire hearing care practice. Otoset, the modern ear cleaning device. Fader plugs the world's first custom adjustable ear plug. Welcome back to another episode of the Hearing Matters podcast. I'm your founder and host, blaise Delfino, and, as a friendly reminder, this podcast is separate from my work at Starkey.

Speaker 2: 0:52

Good afternoon, this is Dr Douglas Beck with the Hearing Matters podcast, and today I am honored to work with my friend, dr Grant Surchfeld. I met Dr Surchfeld many years ago five, ten years ago when I was in New Zealand and we had a wonderful exchange of information and his students were absolutely stellar. So let me tell you a little bit about Dr Surchfeld and then we'll start speaking about many of his research projects. Grant completed his master's in audiology in 1994 and his doctorate at University of Auckland in 2004. That's in New Zealand and he is a professor in audiology and head of the University of Auckland's audiology section.

Speaker 2: 1:31

Dr Searchfeld is deputy director of Eisdell Moore Center for Hearing and Balance Research, primary investigator in the Center for Brain Research and T Tautoki Matora, the New Zealand MedTech Research Translator. He's a specialty editor for the tinnitus in Frontiers in Audiology one of my favorite publications, by the way and associate editor for Frontiers Auditory Cognitive Neuroscience. Dr Sertschfeld's research focus is cognitive processes involved in tinnitus and perception and innovative technology for the management of hearing loss and tinnitus, and he's the scientific director of True Silence and tinnitustunescom. Grant, welcome, it's so nice to see you.

Speaker 3: 2:15

It's great to talk to you again, Doug. Yeah, fantastic.

Speaker 2: 2:17

Well, thank you, and tell me a little bit what's beyond your left shoulder there. What are we looking at?

Speaker 3: 2:22

Yeah, so this is a slide. This is official slide of the university of auckland, the background slide for our talks and so on. Uh, what we have over, uh, one shoulder here is, uh, the university of auckland in the background. Um, you can see where a city bounded by sea, yes, and we also have a piece of ma art Maori. The indigenous people of New Zealand make up around about 25% of the overall population and travel to New Zealand through their waka, their canoes, about 1,000 years ago, in great sea journeys, navigating by the stars through the Pacific, and this was one of the last places that was inhabited by humans in terms of the global discovery and movement through the world. So it's a relatively young country in terms of human population, with New Zealand Europeans like myself venturing here in the 1800s.

Speaker 2: 3:22

So that's a little bit about New.

Speaker 3: 3:23

Zealand.

Speaker 2: 3:24

It's an amazing thing and we're not even going to discuss kiwifruit, but the thing is, of all the countries I've visited and I'm very, very, very super amazingly fortunate, I have to say, as many people have New Zealand is just the most beautiful country in the world and to me it's second only to Scotland, which is you know anyway. So listen, you're here because of your brilliance and your publications and your stature in our community, and you just released a brand new paper which I found kind of fascinating a scoping review of the spatial perception of tinnitus and a guideline for the minimum reporting of tinnitus location. I never even thought about this prior to reading your paper, because I would say to patients is it left ear, right ear, do you feel it? Do you perceive it in the center of your head? Is it outside? But you've actually correlated some very, very interesting outcomes here. So please tell us about this. This is rather fascinating.

Speaker 3: 4:20

When we think about hearing, obviously the first thing that pops into our mind is speech or musicians will think about music, you know, and that's natural. But one of the very basic, primary uses of hearing is spatial perception and in terms of our ability to navigate around the world, this is a key thing, right? This is our survival sense, absolutely. And when we see that with animals, you know, we know that they use their hearing very much to detect threats in their environment. But in an older environment, a more primitive environment, it's the case for us as well. We have to be able to hear threats and then react to them. So we can imagine we're walking down the street and we hear a siren. We're going to look to see where that's coming from because we perceive that as a threat to us. And if we are cued in some way to to think about this, then we have a lot of reactions. Let's say, I'm walking down the street because I'm wondering where my child was riding their bike and they haven't come home, and then I hear a siren. Well, hearing that siren, I'm locating it, but I'm also associating it with all these other factors that the brain's thinking about. So the perception of sound and space is heavily linked to emotional action and reaction. So when we think about it in the tinnitus case, often when people first experience tinnitus, they go looking for where that sound is coming from because they think, well, okay, what's making it?

Speaker 3: 5:58

I had an example of a person who heard a cricket and for a while it was summertime so they just thought it was somewhere in and around their house and they'd look for it. They couldn't find it. It was only when they were out fishing in the middle of the ocean that they realized actually that this cricket wasn't accompanying them wherever they was going. It was in their head and then that's when it actually moved from something that was quite benign into something that was a little bit more threatening and worrying for them.

Speaker 3: 6:26

So our spatial hearing is incredibly important for locating and reacting to threats. If we can identify what the threat is, we can interact with it, we can deal with it. Then it fades into the background. But if we can't, it remains something that we need to focus in on, and when we focus in on it, we become better at hearing it, and this is the scenario that we believe plays a very important role in tinnitus perception. So the motivator behind looking at the literature in this space was driven by our own interest in spatial perception of tinnitus and some work that we've done to try and assess that and then to manage it. But it was really about trying to say, okay, what is the state of play? You know, what do we know about the spatial perception of tinnitus, both from perceptual reporting concept, like you were saying, left, right, center of the head, looking at some of the neurophysiological mechanisms, but also exploring the ways that people have perhaps tried to use the spatial perception of tinnitus in a treatment-related focus. That really was the motivator behind it.

Speaker 2: 7:45

Yeah. So a couple of things. That brings to mind. Number one to me, when I think about localization in three-dimensional space, you know, spatialized hearing, the two primary factors to me are interaural loudness differences and interaural timing differences. Interaural timing differences below 1,500 hertz. Interaural loudness differences above 1,500. Where we 1500 hertz. Inter-oral loudness differences above 1500.

Speaker 2: 8:07

Where we have the largest inter-oral loudness differences is about 5,000, 6,000, 7,000 hertz. That is, if somebody was speaking one meter from my right ear and you measure 250 hertz, it'd be louder in my right ear than my left, but not by a lot. When you get up to six, 7,000 Hertz, the difference is 20, 22 decibels. Now that difference really allows me to tell where something is occurring in space. And then you have, of course, interval timing differences.

Speaker 2: 8:36

Again, if it's one meter from my right ear, it's happening over here. I'm hearing it, first in my right ear, second in my left ear, and so I have all these reinforcement mechanisms that my brain is doing automatically to tell me where the sound is coming from in space. Now, oddly, when I read this article I thought you know, the most common frequencies for tinnitus are 5,000, 6,000, 7,000 hertz. Right, they're tonal and they're about 5,000, 6,000, 7,000 hertz, and when I started to apply the interaural loudness differences to the tinnitus model, it started to make sense to me that maybe that's going to impact your not necessarily your diagnosis, but your treatment protocol, because it might be based on where the patient is perceiving it.

Speaker 3: 9:17

Yeah, of course, when we're talking about tinnitus we're not having that physical sound. And so you know, when we use sound, for example, to match the position of tinnitus, we're not having that physical sound. And so you know, when we use sound, for example, to match the position of tinnitus, we're using exactly those cues that you're talking about and also spectral cues which give us the height of the sound. You know, people say it's in my right ear and it may be that they like it. But then you say is it above your ear or below your ear? And people actually can precisely locate this. For some people it's a vague sensation in and around the ear, but for other people it has a very specific site that can be located and we can manipulate it.

Speaker 2: 10:03

How would you use this information with regard to management or treatment of tinnitus?

Speaker 3: 11:24

Yeah. So you know, classically, if we look at masking right, we have, when we're masking, an audiometry. Let's take that basic example. We've got a sound on one side that we are trying to prevent the other ear from hearing, so we'll turn up the sound in the opposite ear, you know, and that makes a lot of sense If we're thinking about it from a hearing aid perspective and listening to people. We know that if people are separated in space, it's easier to hear which person is hearing, and if they're overlapping and they're talking from the same position, it becomes more difficult. So the way, one aspect of how we've approached this is to say well, can we actually improve the masking approach that is generally applied? So if a person hears tinnitus in a particular position, say the front of their head to one side, we can then manipulate the sound that we're playing to be perceived as coming from the same location.

Speaker 1: 12:29

So not separated right.

Speaker 3: 12:31

So if we play traditional masking sound through one ear, we'll hear it in that ear. If we play another sound, we'll either hear it as two separate sounds or, if they happen to be at appropriate phase, we'll hear it in the centre of the head. But we can actually manipulate that and if we do that we find that we're easier able to cover the sound in terms of the level of sound that's required. So we can effectively mask, partially mask or interfere with tinnitus at a much lower level, which makes it more pleasant and more effective. So that's one way of using it. The other way of thinking about it is in terms of saying well, tinnitus has this spectral component and a lot of treatments and a lot of ways that we assess tinnitus, use pitch matching in some way.

Speaker 3: 13:27

Well, we can also use a spatial location of tinnitus and I think one of the most effective ways that we've found is to incorporate that within auditory training, where we create an avatar, a copy of the tinnitus, and we incorporate that within an auditory training environment, a reasonably fun, game-like scenario, where effectively, we're training people not to hear their tinnitus avatar so their attention is drawn away from this sound which, you know, their survival sense is trying to lock into and focus on and we're taxing the auditory system and training it to listen to sounds remote from it in frequency and pitch, but also remote and spatial perception, and then we can migrate through to removing the avatar and the individual, focusing on their own tinnitus and then moving through to applying this in everyday life.

Speaker 3: 14:26

So there's a number of ways and we see this is really important to see tinnitus. As you know and you've written about before, you can't really tackle it from one direction. You know you've got to include the counselling and other aspects. So we see a little bit of relief, a little bit of relaxing and a little bit of retraining and the combination of those things right for the individual. Each of those aspects incorporates a little bit of the spatial perception aspect to try and train what fundamentally one could argue is the basic role of the auditory system and localizing sound.

Speaker 3: 15:07

So, that's the way that we really approach it.

Speaker 2: 15:09

This is fantastic. So when you have diagnosed a patient and you've got the pitch of their tinnitus and the loudness they perceive it and its location in space, what tools? Without mentioning a particular manufacturer? But how do you do that?

Speaker 3: 15:25

Yeah, yeah yeah, so originally we took off-the-shelf audio processing software and we would have to go in and manipulate things manually, and they gave us the proof of principle where you could actually do this, you know, uh, and we would do that under headphones, um, okay. Then we moved to in situ testing, where we would in fact, um and this was originally before bluetooth, so we were using audio jacks into the hearing aid and hardwiring it, and then we moved to Bluetooth.

Speaker 3: 16:00

So the way that we do this now is that we have some software and we're able to go through that process and we manipulate it in 3D space, not only in the horizontal but also the vertical, so we create this global presentation. It certainly is assisted when an individual has a visual cue as well, because people will know, working in the spatial audio aspect, it's relatively easy to localize things on 45 degree angles, but there are things like front back confusion and so we need to do some checking of that. But what we actually found was that spatial localization in terms of within-session and between-session reliability if people report that their tinnitus hasn't changed in location, which is another thing we have to account for is that the accuracy is pretty high. It's around about the same reliability as pitch matching, a little bit more than the loudness matching. And one of the values of this and thinking about the auditory training is that we know, for example, that tinnitus can change right.

Speaker 3: 17:14

Absolutely it can change in level, it can change in frequency, but it also changes in spatial perception.

Speaker 3: 17:21

Oh, that's, very interesting and you know that may depend a little bit on hearing in one ear or the other, or the most prominent sound that can change. And so one of the really important things in training that we've found is that we're actually training on the right thing. Yeah, so, in our training protocols every time that we go found is that we're actually training on the right thing. Yeah so, and how our training protocols? Every time that we go into the training we have to go through a spatial tinnitus recalibration process.

Speaker 1: 17:48

so that you're actually sure that as it is at that particular point in time do you have can be done, you know, and, as I say, it's brilliant.

Speaker 3: 17:57

People, people will vary a lot. You know, some it's very punctate, yeah, some it's very broad.

Speaker 2: 18:02

People obviously hear multiple sounds, so you can incorporate, uh those uh different aspects into an assessment and so tell me your approach to masking, because if somebody hears a tone let's say they heard 6500 hertz what masking sound would you use to try to help them acclimatize to that?

Speaker 3: 18:20

You know this is an area of great debate, right, you know, and people will put a lot of emphasis on a particular sound. Sure, first and foremost, we have to be pragmatic. It can't be a sound that people aren't going to listen to, right it?

Speaker 3: 18:36

has to be a sound that can be comfortably listened to and depending on how they're using it.

Speaker 3: 18:43

You know, if you're taking a 10 to 3 training therapy approach, you're going to want a sound that is fairly neutral and is used for a long period of time.

Speaker 3: 18:54

Our approach is to try and match the best solution for the individual's needs. So you know, before we go down a particular road of trying to choose a therapy sound, we're trying to assess how the person is going to use it. We can make our recommendations right, but we all know that when a person leaves the clinic they're going to apply it the way that that they can sure, um, and we will recommend certain things and they'll try their best, but lifestyle and so we'll govern that. So we need to understand that, uh, and we need to to think about what works within a person's environment. If I'm going to say you know what would be the go-to standard if people were fairly nonplussed about what they were going to try, it would be some form of broadband noise. You know we've done quite a lot of work looking at different aspects of the spectral content of sound, compared broadband noise to nature sounds, the goal has to be the comfortable sound, the sound that they're willing to listen to right.

Speaker 3: 20:07

What are people comfortable with listening to in a particular type in a particular environment? Some variety that people can choose is good, but people will tend to settle on something. Even if we look at, for example, the concept of adjustment for the degree of hearing loss, you know that many products you can provide compensation if there's a hearing loss there. So, effectively, what for most people that will be is a high frequency boost. Yeah, now, I firmly believe that that actually is going to be, um, the most effective sound for the majority of people in terms of, uh, neurophysiological mechanism.

Speaker 2: 20:52

The efficacy is there but will they listen to it exactly?

Speaker 3: 20:57

and so you know there has to be this trade-off and this is the advantage I think of. You know we're clearly advantageous listening to our clients and understanding their perception. That. You know we shouldn't be afraid of a little bit of try and see in in the beginning. You know we can go in with some clear recommendations and what works on average. But if we find it's not working, you know let's change tech. And also I'm firmly actually of the belief that you can get a fairly good idea if it's going to work or not actually in the clinic in that first consultation. You know, in the case of hearing aids, even if we're not fitting a background sound, we're using amplification. Sure.

Speaker 3: 21:43

If you put the hearing aids on and they notice a change and they're not as aware of their tinnitus. Long term, you can be pretty much assured that that's going to work. You know there will be variations on that. Yeah, yeah, they put the hearing aids on and they hear. Their tinnitus hasn't changed. My belief is that's going to be a harder road moving forward, making the change.

Speaker 2: 22:04

I think that's fair yeah.

Speaker 3: 22:05

There are going to be other things that play a role there. In general, we can get a fairly good sense in that initial consultation, the fitting process about where people are going to go, and then we need to think, okay, well, we obviously don't want an unsatisfactory outcome, so for those who are not getting the benefit, what are we going to do? What are we going to do about that? How can we help them? Additionally and this can mean we can tune our counselling yeah, and it's always got to be individualised to the specific patient.

Speaker 2: 22:36

You know it's good to have the overview and to have oversight and a 30,000 foot viewpoint, but each patient is an N of one and so you know we have to meet them where they are and treat based on their signs, symptoms and what works for them. As far as a potential masking sound One of the things that I've been doing these last few years with regards to tinnitus I read a paper. Michael Merzenich who is a genius you know wrote this paper about broadband noise and white noise and those are the same thing. The definition of white noise or broadband noise is all frequencies at the same volume for people who are unaware of this, and so it's like a is what it sounds like, and Dr Merzenich was saying that.

Speaker 2: 23:18

You know that could be actually very dissatisfying to many people because their central nervous system gets used to that constant barrage of stimuli and maybe that's not a great idea and that had to be gosh, I don't even know anymore. I'd say eight or 10 years ago that he published that. But that got me thinking and working more on environmental sounds, you know, and just turning up the gain, even in a quiet environment I would mostly focus on environmental sounds because I thought that that would be potentially better in the long term for someone to adapt to, get used to and defocus on whatever their sound was. Now it doesn't work for everybody because, again, the most common sounds of tinnitus are going to be tonal and electrical wire sounds and you have a hard time masking or offering an alternative sound with environmental sounds because they're higher pitched and they're more difficult. So your thoughts share with me. What do you think about this?

Speaker 3: 24:20

So you know we've been working on a system, a therapeutic board for tinnitus. So you know conflict of interest there and what we've been working on. But all these parts are valuable for some people some of the time, and you know your comment about the individual nature of of tinnitus, and so that personalization is incredibly important. And you know the traditional randomized control trial that people have done, where we have compared broadband noise to nature sounds, for example. Right, and they come out fairly even. Well, the problem is that is the nature of things. They're randomly assigned, but actually within each group there are probably people that will do better with nature sounds, but they're provided with broadband noise, and likewise the other way around. So I think that that's one aspect that we will improve with, and we know we can begin to get there with AI, for example. We've been applying AI to try and guide us to this. But what I think is that for long-term treatment of the tinnitus, as opposed to palliative management, there needs to be a progression, we believe, from a sense of relief enabling relaxation to to gain control of those environments that are stressful. But the retraining part of it also needs to move from perhaps a structured training environment that we are looking at providing in our digital therapeutic through to tasks that people can actually do on their own. Yeah, right, exactly, you know, cognitive behavioral therapy, for example, would go and train people to do particular tasks. All right, uh, what we're really saying is that we, we can provide that in a a manner that gives the individual a lot of control and is easier to do than potentially learning the full cognitive behavioral techniques of attention diversion and so on, so we can automate that, we can train individuals, we can use auditory stimuli, we can use the tinnitus avatar, but we need to be able to translate that from I'm doing it now into when I don't have my therapeutic with me and apply it.

Speaker 3: 27:02

So I think a long way in answering your question there, doug, is I agree that certain sounds, certain individuals, have certain value, and what you're trying to do in these tasks potentially are targeting different parts of a tinnitus network. So, for example, we may, using broadband noise, be acting on the auditory component where we're really trying to reduce the ability to extract information right when we're listening to other sounds. Then we're bringing in auditory selective attention. Yes, and you know, this is where spatial aspects can be great as well, because not only are you, you're hearing the different sounds, you're trying to work out where they are, which is the, the primary function. It falls on cognitive resources, right, and if you don't have the resource to think about the tinnitus, you're spending less attention, you're focusing on it less. Basically, that signal diminishes within the auditory system and so you can basically train your way from perception of tinnitus to perceiving the outside world and much greater.

Speaker 3: 28:20

So you're acting on different parts of the auditory network, and now EEG studies have been able to demonstrate this as well before and after these types which you've published quite a bit on, yeah, yeah where we see, okay, before we've got this broad activation and when we're providing this spatial relay training, we're actually getting changes, yes, in the auditory cortex, but also in the occipital, parietal region of the brain, which is very much involved in sensory integration, often associated with vision, sure Recognition and pulling these things together.

Speaker 3: 28:52

And that's one of the big changes, for when you see modeling of a tinnitus brain and a brain that's after therapy that's been successful with these changes in the parietal occipital region.

Speaker 3: 29:06

So if we think of tinnitus as a very complex network with different nodes that each are playing a role, we can shut down one node, but we risk that the other one is going to take priority. Right, we can interfere with the hearing part of it, but the emotional part may increase. So we've really got to look at these in different ways and it's such a complex thing, so different from individual to individual, that this network physiology is incredibly interesting and but I think we do need to tackle things and up our game many, in many ways and think and rather than thinking of tinnitus just as a auditory perception of tinnitus, but you know, we always thought about emotion and things like that, you know, and we've tackled that by counseling and cognition, but but we really need to integrate these things much more, I think. And now you know, with a digital capability and an ability to manipulate sound, yes, and particularly 3D.

Speaker 3: 30:09

Much more closer to being able to realize that.

Speaker 2: 30:12

So you know these are, these are issues we've been struggling with for decades. You mentioned in passing TRT, so for those unaware, that is Powell Jastuboff came up with that from Annemarie University. And then we had PTM Progressive Tinnitus Management from the group in Oregon Health Sciences, dr Henry and colleagues. One of the things you mentioned that, oh, I'll tell you my thoughts and then I want you to comment because I'm probably wrong. But you know, the single largest, the single most effective therapy for tinnitus has long been known to be CBT cognitive behavioral therapy and I had a paper I wrote this past year on that and I said the problem with everybody with tinnitus getting CBT is this 80% of people with tinnitus have hearing loss and if we just solve the problem from the point of cognitive behavioral therapy, they have undiagnosed hearing loss and that's going to lead to additional problem and sequelae and things.

Speaker 2: 31:07

So what I've always thought and I want your opinion on this I've always thought people with tinnitus should really see an audiologist first or a hearing care professional first and get diagnosed, get a complete audiometric evaluation tinnitus matching, tinnitus frequency matching, maybe tinnitus handicap inventory let's really investigate this and then we can try audiometric technologies and techniques. Failing that you know there's a lot of hope because CBT is still out there. But I've always approached it audiology first, because I wrote a paper it must have been 10 or 12 years ago where I said 80% of patients with hearing loss have tinnitus and 80% of people with tinnitus have hearing loss usually not diagnosed. So that's where I came to that belief that you've got to go through audiology and hearing care professionals first and then manage tinnitus. What are your thoughts on that? And hearing care professionals first and then manage tinnitus what are your thoughts?

Speaker 3: 32:00

on that. Tinnitus is best managed in a multidisciplinary environment, but that doesn't mean that the audiologist has to be in a hospital, right? What it means is you need the networks and you need to be able to think about how is this management going right? If you're working with a patient and something's not working, then you should assess well, okay, what can I do to improve this? And that might be if there's anxiety and depression and maybe a referral it doesn't mean that you are somehow losing a client.

Speaker 3: 32:38

It's meaning you're enhancing your practice. That's right, right and so. So my feeling about this is that a lot of people also fear doing tinnitus work right. You know, we talk to audiologists and they are concerned. I I suspect that they that they're going to have to provide additional levels of counselling and demand from clients and they're perhaps not used to the same emotional context of tinnitus, with tinnitus even coming to our tinnitus clinic, have come to the point where some of that emotional aspect, their reaction to it, is under control or it was never a huge problem. So the majority of people that are going to have tinnitus may see it actually as an audiological problem and the associated psychological components, while they play a role, may not be severe. There's going to be a small percentage of people that have it severe and we need to think about at that time our network and our referral network, managing the audiological components, referring for those other parts. So you know, one of the things that we're trying to do is to provide tools for clinicians who may have been reluctant to get into the tinnitus space, to equip them with the tools that they can do, that they can manage things much the same way that they manage hearing loss. They can extend their, their networks, but they also can enable a pathway where they're seeing people that can become part of their clinic family, if you like. I think that we can establish this and you know when you've talked about this. We know this in the cognitive space, right, absolutely. We know this broadly that we this broadly that we do ourselves a disservice when we are perceived as dispensers because we think we're singularly motivated in and around the sales of devices and things like that. If we can provide a comprehensive service, it doesn't mean we're diminishing that. We're enhancing that by our overall practice.

Speaker 3: 34:56

So I think that when we are looking at tinnitus practice, we need to understand who are our different referral sources. We see a person that's got a neck problem, who's got neck pain. They can move their neck and their tinnitus changes. You know physical therapy. Do we have a physical therapist we can refer to? They're going to come back to us for their hearing, right? Yes, a cognitive behavioral therapist. We've got a person that's got severe anxiety depression. It appears that their tinnitus is there. They're perhaps relating some of their problems to their tinnitus, but clearly there are other things that are happening there, sure, and I love cognitive behavioral therapy. They're coming back to us for our the hearing needs. They may still, you know, they may still benefit from assistance with some some therapy background sound, you know, and cognitive behavioral therapy is a very big umbrella and elements of that oh sure you know, recommend use of sound in the background.

Speaker 3: 35:58

So you know, we like to and we need to, because of established systems, have these professional groups, you know, and we need to be careful about professional boundaries and scope of practice, but we don't need to create barriers and interdisciplinary uh work is one of the great things that we can do and great, and you know. Again, thinking about the business model OK, I'm concerned, I'm referring my clients through to a psychologist. Well, hey, you know if they can then be referrals back to us. So I think that we just have to think about that broader health care space.

Speaker 2: 36:38

Yeah, and I think the multidisciplinary approach has always been the best approach. You know, we each use our area of expertise to help diagnose and treat the patient, so I think that makes great sense. Now I'm going to pull the rug out from under you and switch topics entirely. You published a paper four or five months ago that was absolutely fascinating and I have to say many of my colleagues did not hear about this paper and they should. It was a paper that was called the CogniAid Trial the impact of two hearing aid signal processing strategies on cognition and I'll give you my summary and you correct it.

Speaker 2: 37:13

Basically, you had, in the end you had about 50 people, something like that, 60 people who were fitted with they that mild to moderate sensorineural hearing loss. They were fitted with two different fitting protocols. One was sort of a linear protocol, which is a very basic, plain Jane but very adequate for many people, and then you had a compression strategy, multiband compression strategy, and you found that more or less the people who were fitted with the multiband compression actually had an improvement in their cognitive ability that was substantially improved over those who had linear fitting, who had linear fitting, and this was a fluid intelligence measure, and fluid intelligence is the ability to think, to reason, to be flexible, to incorporate sensory perceptions and come up with a new conclusion, whereas crystallized intelligence, those would be things that you know, facts, things you remember. So crystallized intelligence is you know that two and two is four. You know that 32 times two is 64. That's you know north, south, east, west, you know all those things. But fluid intelligence is the ability to reason and to think, and that's where you saw the difference.

Speaker 2: 39:15

So that's the overview of the study and I. That was entirely too brief of a detail, but please fill me in. What did you do and what did you find? Because I found this to be incredible.

Speaker 3: 39:25

Yeah, so our finding was opposite to what we expected. All right, so in some ways, you know, we went into this with one idea and actually we found the opposite to what we had hypothesized, yeah, which, from a point of view of bias, is great because, you know, you weren't biased towards this. There's no manipulation here. What was the reason for doing this? Well, our rationale was, and our hypothesis is, that in short term, in laboratory experiments, this has been shown back. You know the work at Gatehouse and so on Stuart Gatehouse.

Speaker 3: 40:06

Actually, people that have poor short-term memory, so poor cognition, tend to do better short-term with simple processing strategies. And the argument there has been that, from a cognitive capacity point of view, of a speed of processing, that compression strategies, which provide a lot of information you know, just swamp the person. They just can't use all the information. If you, if you're cognitively adept, you can extract the information, you can get most of it and and further.

Speaker 2: 40:45

Linear is a truer amplification strategy. Compression is more distortion when we compress. Yeah, yeah two to one, three to one, four to one. We're distorting the heck out of them, but in a typical outer hair cell deficit situation the patient is able to use that to their advantage. But I would have had exactly the same thought process going in is that the people with linear amplification may well do better on this because of less distortion.

Speaker 3: 41:13

Yeah. So we took this very basic approach. Right. We fit hearing aids old school, yeah, all right, they were modern hearing aids. The technology in both groups were very similar Multiple brands. The individuals were self-selecting, they were coming through the clinic, they were paying for the hearing aids themselves. We're trying to reduce any bias of cost or anything like that. It's just when we fit the hearing aids, right after they were chosen, they were randomized to the linear or the nonlinear fitting and we chose to fit to now R right, yeah.

Speaker 3: 41:51

Okay, and now nonlinear one or two. So if you look at mid-frequency gain at an average level so just an average level these prescriptions are very similar, knowing that the linear prescription is the same no matter what. So we went in there. Uh, that was the main, main thing. We also thought that we probably shouldn't have things like frequency lowering or transposition in our simple group. Yeah, too many variables. Yeah, the argument was keep it simple, stupid in a sense, that we want to keep the processing simple, right so that the people can extract as much information out of that as possible. Right Now, we went and we believed that long term that would get the best result and we fit the other hearing aids as we would at best practice. What was interesting is six months, 12 months, as we went along, we saw this progression. Caring, handicap, complaint outcomes were very similar between the two groups, right, so we didn't really see an advantage or disadvantage of the linear versus the non-linear approach there.

Speaker 3: 43:09

Rightometrically the result and I should say that when we recruited people to the study, uh, we tested a whole, whole lot of people for their cognitive abilities and, uh, we only fitted individuals had that had below average cognition. It did not indicate they had dementia, which is, you know, really important. It was just that we felt okay, if we have people in our groups that have great cognitive ability, you know we're not going to make better, better right, so we're going to stay with this group, but they were evenly balanced between the two groups.

Speaker 3: 43:44

Ultimately, when we got to 12 months, outcomes were very similar between the groups, except for fluid cognition and, the opposite to what we expected, that the group that received the standard protocol compression improved the most on their cognitive ability and you know it was progressive from baseline six months, 12 months. Yes, the other group also improved. Right, those receiving the linear hearing aid improved over that period of time, but not as much. Uh, it surprised us. And then so we're thinking okay, well, why although we we can't necessarily prove a lot of these hypotheses that came out of this study, you know, because we didn't look at them specifically, but they're things to be answered in the future Do we believe it's because the people with compression had more social interaction or were doing better with their hearing? We can't say that for sure but we don't necessarily think so because the hearing outcomes were very similar that the compression strategy, people weren't saying they were hearing better.

Speaker 3: 44:59

Our feeling is that it's really the cognitive challenge that it places, basically in that first period of time when people get complex hearing aids and they weren't doing so well in those early studies you know the gatehouse type studies. They were really cognitively challenged by the more complex processing. They weren't doing it so well. But actually if you keep on doing that challenge for three weeks, six weeks, 12 months, if you keep that challenge up, as long as people are continuing to use their hearing aids and not give a gun perhaps that challenge and demand on their hearing system by making all this information now available not just average speech, but quiet speech as well that that that cognitive challenge is essentially an exercise for the brain.

Speaker 3: 45:53

So our working hypothesis is that counter to our initial hypothesis that if people can be fit with these complex algorithms that enable a lot of information to be available and they can continue to use their hearing aids and data logging showed that both groups were using their hearing aids six to eight hours per day, you know there wasn't a difference between the two groups there. If we can do that, then perhaps actually making all this information available is good. What does this mean in terms of you know, because essentially what we said was actually standard practice is better long-term, but what does you know? The initial challenge that people have in the clinic, you know, is do we need to stage this in some way? Do we need to take a little bit more of a longitudinal view, where perhaps our initial prescription is relatively simple, to give people a starting point, yeah, and then maybe six months, maybe shorter than that, and it's a little bit more than the concept of, you know, adaptation to sound. You know it's a cognitive adaptation, it's a cognitive challenge.

Speaker 2: 47:19

As we go through, we could be providing more and more cognitive challenge passively and that's going to have a better cognitive outcome the finding uh in in your conclusion you stated very clearly the results reinforce findings indicating that hearing aid benefits for the elderly and the people who were selected for the study and that they improve cognition. And this is still something that that people struggle with, even though we've got so many studies now that have shown in selected populations people do improve. We can't guarantee that, we can't promise. We should never use that as a scare tactic. But the reality is that when we look at the enhanced study out of Australia, they found that the people who were fitted with hearing aids for three years did not decrease in any of the cognitive abilities where the people who did not wear hearing aids decreased. We have, of course, the ACHIEVE study. Here's how I interpret the ACHIEVE study, which, by the way, is a brilliant study. But they took about 1,000 people over three years and what they said is ultimately there were no differences in people who wore the hearing aids, but that was compared to people who got excellent counseling. So you had these two groups and said, oh, there's no difference. They they look the same. Okay, that's fine, but there's no untreated group. So the hearing aids may have made a big difference and the the um educational, uh, rehab and training that the other people got may have made a bit, but they've made the same difference. So we didn't see a difference. So that's an important point. But then when you looked at the second analysis, where they looked at people who were older, people who had more comorbidities, people who were in lower socioeconomic groups, I think very similar to what you found is that those people actually decrease the anticipated cognitive deficits by about 48% over three years.

Speaker 2: 49:13

So we are starting to see that in selected groups, over time, the people who are fitted with hearing aids may do well. We may slow the decline, we may alter the trajectory, and nobody's promising anything. We're just saying that to ignore that these benefits have happened in just the three studies I mentioned, but there's many, many more. Johns Hopkins did a study they published in 2022 or 2023, where they looked at 900 people with moderately severe hearing loss and they found that the people who were treated with hearing aids people with moderately severe hearing loss and they found that the people who were treated with hearing aids in the moderately severe group had one third less cognitive decline. So there are many studies that have shown this.

Speaker 2: 50:00

Now the big issue is you can't promise, you can't threaten, you can't scare. But I think we have to be honest about this and we expect a higher quality of life. And you can go back 20 years ago 24 years ago really to Sergei Kochkin and Carol Rogin's National Council of the Aging, where they showed like 20 benefits of fitting with amplification. But now it's 24 years later and we know that other benefits of amplification may include, for some people, the delayed declines that we often see in the general population.

Speaker 2: 50:30

And so I think that it's important to talk about and to refer for these things as well, because cognitive screeners certainly cannot diagnose anybody at any time and audiologists certainly do not determine whether somebody has dementia or microvascular disease or whether they have frontotemporal dementia or Lewy body disorder or vascular dementia or Parkinson's. Have frontotemporal dementia or Lewy body disorder or vascular dementia or Parkinson's? That's not what we do. We say that if they fail a cognitive screening, we should refer them. That is perfectly in alignment with ASHA scope of practice and with AAA scope of practice. So, with all of that rant that I just did, I'm curious what's your thought on this? I mean, should we talk to patients about cognitive decline and should we or should we avoid that?

Speaker 3: 51:14

Well, I think that in many ways this is, and when I came into this study, as you mentioned, it was a sort of step to the side from the tinnitus right, but in many ways, the the complex nature of tinnitus has taught us a lot about how we can think about things in other dimensions, particularly the brain right, right, the brain part of hearing, in terms of the way that tinnitus is, and a lot of these, if we say we could say, conflicts or discussions. You know is, should tinnitus be managed by audiologists or should it be by psychologists? You know that's a long-term discussion. Should audiologists be discussing cognition or should we? We're not. I think, in the terms of this aspect of cognition uh, dementia and hearing we are very early on in the way that we, as audiologists, think about that, and so what's most naturally going to happen is that there are this, this sides, if you like, or different aspects of the debate, and you know I would expect that that knowledge is actually going to pull these things together and everybody then begins to see what their particular place in this space actually is.

Speaker 3: 52:49

So, you know, the results of the study that I mentioned suggests that hearing aids in individuals with below average cognition can help their cognition. So now, that does not say that it's going to long term, prevent dementia, of course, but it's really about what is one potential outcome that might be achieved with hearing aids In some people at some time, in some people some of the time, just like tinnitus right, yeah, some people some of the time. Tinnitus right yeah, some people some of the time. Now, the thing about tinnitus is that we've begun to be say okay, these are the people that some of the time, are going to benefit from this approach. Probably where we are within the dementia cognition discussion is we're still at the place where we don't know hasn't been settled, who, how, what.

Speaker 2: 53:55

Yeah, who can identify?

Speaker 3: 53:58

When we identify what the problem is Right, I would say that there certainly is a role in certain circumstances for the audiologist to take in screening and referral Sure or referral right, you know and what they're screening? Well, we've done them a disservice. If we have concerns about cognition, then we should be thinking about that in our management, which may include referral or other testing. So my belief is that certainly somewhere we are going to need to include cognition in our thought processes. What that is, I think you know, will be refined by time. I don't think we have to recognize it.

Speaker 3: 54:49

Our population is raging, the people that we see as audiologists. They're living longer. They're going to live longer with cognitive impairment that's right and we can't.

Speaker 3: 55:01

We can't put up our hands and say, oh, it's not my, not my problem, it's somebody else's problem, you know, particularly if the audiologist is the key point of contact, if we're the only medical professional or health professional in town, you know, what are we going to do about that? We have to think about that. Yes, we have to carefully consider that. Standards, you know we're thinking about it in our audiology training program you mentioned in the introduction. You know I'm head of the audiology training program here at the university of Auckland. We're thinking about, well, what do we do? You know, are we teaching enough cognition? Should we be teaching this? Yeah, you know what. What do we take out of audiology training? You know, and we should always reevaluate and reevaluate.

Speaker 2: 55:46

It's not like there's one answer right. As time goes on, we have to look at what we've done and change, because you know it's either evolve or die. There's no middle ground. Now one of the things that I want to comment on and I know you've been very generous with your time. I think this recording has now been going on for six hours, but the thing is, the JAMA, the Journal of the American Medical Association, said in 2022, maybe it was 23,. They said mild cognitive impairment is 22% of all adults over age 65.

Speaker 2: 56:16

The American Alzheimer's Association says that by age 85, the chance of having Alzheimer's which, by the way, is only one of some 200 different types of dementia, the chance of having Alzheimer's in particular is one out of three by the time you're age 85. So this is a crisis that's going to happen that we have more and more people. I mean, you know right now we probably have about 50 million, 55, 60 million people have been diagnosed with dementia across the globe, but by 2050, it will be 155 to 165 million people. That's the way the demographics are evolving. We also know that these populations overlap tremendously, exactly as you were saying, with people with hearing loss, people over age 65, you know, one third of them have demonstrable hearing loss. People over age 75, two thirds have demonstrable hearing loss and by the time you hit age 90, 95 percent of people. So these two populations, people with hearing loss and people with cognitive impairments, are, you know, as we age, are much, much greater populations and one leading to the other. It's not causation. Nobody's saying that hearing loss causes dementia. We're saying that the correlation is very, very high and we know these things. We can go back to 1949. Dr Michael Bust, writing in the JSHR, said so.

Speaker 2: 57:43

How do you know that your patient's entire problem this is 70 years ago. How do you know that your patient's problem is completely auditory? In other words, they came to see you because they can't understand speech and noise, they have hearing difficulty and you find a mild to moderate sensory neural loss. You treat them and you say that's it. How do you know that it's not depression? How do you know it's not psychological? How do you know it's not emotional? How do you know that it's not cognitive? And I think his point was and I never met Helmut Michael Busty, it was long before my time but I think the issue is that these things interact and one can certainly impact the other. This is well known to all of us.

Speaker 2: 58:22

When you go back to University of Florida back in the early 2000s, my friend, we're publishing that you know it's not enough to just do peripheral air, bone and speech. You know you have to do more, because we're not speaking specifically about a cochlea, we're speaking about an auditory system. You know it's not just hearing which is perceiving or detecting sound, it's listening which is comprehending sound. You know, and we have to dig deeper. And if we don't, shame on us, because when a patient comes in and says they don't understand speech and noise, that's their most difficult time. Very few audiologists do a speech and noise test and you know it takes five or 10 minutes to do that. But now you can document where the problem is. And if you know where the problem is then you can start to manage and treat it. But to just tell them they're hearing as normal, go away. That's always been ludicrous. I've never bought into that.

Speaker 3: 59:13

Yeah, yeah, I think you know, cognition is a fascinating area and it's critically complex. When we think about this, we need to think about who we are seeing. You know who's in our clinic. Who are we seeing? How are we going to help them? And we know, for example, that individuals with dementia will often also have it's not just about memory, you know. It's about emotion, extreme emotions, fear, anger. And so in preparing audiologists, our future audiologists, upscaling current audiologists, we really need to almost go old school and think about oral rehabilitation in terms of emotion, empathy, these sorts of things. And I think you know, putting aside the debate about cause, effect um dementia hearing, I think we probably all can agree that happy hearing, healthy aging, you know and and so, and if we we take that approach and with that we, we can see a number of different things there.

Speaker 3: 1:00:27

There's about the hearing, but we've got to be happy with it. It's that emotional context of hearing. It's tied in with the aging process. We need to consider that. We need to find out ways of incorporating that into practice, because people are living longer. We're going to be seeing them, they're going to be physically sound, wearing hearing aids in environments where they want to use them, but because of the aging process, at least for now, they will have cognitive decline and so we can't ignore this. How we best employ it I is a is a great challenge and you know, having worked in the tinnitus space, which is an equal, equal challenge, I think it's a fascinating area to be engaged in. It will evolve. We need to be careful, uh, and I think you know, possibly in and around the messaging is where there has been the greatest sort of pushback in and around this space, and I think that we can be careful around that without diminishing the fact that this is really important, absolutely yes.

Speaker 3: 1:01:41

And we, as audiologists, are in a great position to do something about this. Absolutely, we need to be trained in it. Yeah, we need to be aware of it. Yeah, we need to understand how best to use our audiological skills in, in related to this, and you know, um, cognition is cognition, but there are elements that are auditory, absolutely well and when we talk about auditory processing disorder, you know often we focus in on, you know, children and developmental things.

Speaker 3: 1:02:13

But if we think you know, older age sort of mirrors our younger growth and we sort of regress towards younger, that is bound to have an effect there. And so when we're thinking about cognition, you know there are going to be elements that are very strongly related to hearing Absolutely, and who is best to manage those aspects of it. But if hearing loss is related to poorer auditory selective attention actually that's what we should be thinking about Because of the aging process a small amount of hearing loss may in fact cause a large auditory selective attention process. Don't know that, but it makes sense, we need to research it right. And so I think we needn't diminish auditory aspects of cognition Right, because that is something that we should be focusing in on.

Speaker 2: 1:03:17

Anyway, dr Searchville, it is a pleasure to hang out with you and to spend time with you. I hope I get to see you down in New Zealand one of these days again soon. You're certainly welcome to come up to San Antonio and we'd love to have you here, and I wish you nothing but joy and continued success. Your research papers on tinnitus and cognition and hearing aids are very, very important and I'm so proud of you for writing them.

Speaker 3: 1:03:41

Thanks very much, doug, and I look forward to coming and visiting you on my trips to the United States. And I would say to your viewers many of you will be in North America, come on down, come on down send me an email before you come and we'll see if we can show you around.

Speaker 2: 1:03:57

Thanks, grant, take good care, I'll see you soon, thank you.