Middle Aged Adults with Normal Audiograms and Self-Reported Hearing Difficulties: How Research Informs Care

Hello, and welcome to another episode of this Week in Hearing. I’m Brian Taylor, and this week our topic is adults with normal audiograms and self reported hearing difficulty. And here to discuss this important topic is Professor Christina Roup from the Ohio State University. Welcome to This Week in Hearing. Christina. It’s great to have you with us. Thanks so much. It’s a pleasure to be here. Well, this is kind of a burning topic for a lot of clinicians out there. I know that In my travels, I talk to a lot of audiologists that run into these patients that have normal audiograms and report difficulty. But before we dive into the topic, I thought it would be helpful if you could tell everybody a little bit about your background and what got you interested in this topic. Well, sure, yeah, thanks for asking. So as you mentioned, I’m currently a faculty member at The Ohio State University. I’ve been there since 2004, and I have been a teacher in the classroom with graduate students and undergrads. But I also have my own research lab where I study primarily age related changes in speech understanding, but that has evolved into changes in speech perception, speech understanding, speech in noise problems in adults who have normal pure tone thresholds or thresholds that are within this normal range. Prior to that, I spent six years in the Department of Veterans Affairs, where I was a research and a clinical audiologist there. Well, it’s great to have you on our episode devoted to this topic. And my first question is really maybe more about semantics, but could you describe the condition? I know it goes by a lot of different names, and in addition to maybe talking about some of the different names, if you could explain some of the theories around what’s happening on the auditory system. Sure, you’re absolutely right. The more you dive into this topic, the more you learn how many different names it goes by. So probably the most common name that we hear is either Central Auditory Processing Disorder or auditory Processing disorder. But people do get there’s a little controversy surrounding the term disorder. Right? So other terms have been used. One of the more recent is hearing difficulties. That was coined by Kelly Tremblay. Looking at the data from the Beaver Dam Epidemiology of Hearing Loss study, this was first described this concept of normal pure tone hearing thresholds and speech in noise problems way back in the 1940s. And so that description was later termed King Kopetzky Syndrome. So that’s one term. Obscure auditory dysfunction is another term. I use the term hearing difficulties or auditory processing deficits. Those are two terms that I typically use. So there’s a whole host of terms. Central Presbycusis is another. You can tell I can go on forever with terms. Right, but getting to the second part of your question, what do we think is actually happening with these individuals? Right? So I think there are a number of different things that have been demonstrated in the research to help explain these symptoms. Aging is one of them. So we see these symptoms where we have middle aged and older adult listeners who have hearing within the normal limits that are presenting with these symptoms, suprathreshold deficits or speech in noise deficits. The middle aged population is one that I find super interesting because there’s not a lot of literature in this area. Right. But these are people who are presenting in the clinic. And Karen Helfer has a series of articles looking at middle aged listeners and their auditory functioning. So if anyone’s interested, that’s a great line of research. The other thing that we’re beginning to see is the importance of extended high frequency hearing, right? So thresholds above 8 kHz, so thresholds at ten through 20 kHz, we’re learning that they have a lot more importance to our supra threshold hearing abilities than we ever thought before. So we’re seeing that extended high frequency hearing is related to speech in noise performance. There was a great study that came out of the National Acoustics Laboratories in Australia by Ingrid Yeend she published a study in 2019 with colleagues that showed that extended high frequency hearing was a significant predictor of speech in noise performance. And she’s not the only one to have shown that. So we see that extended high frequency hearing, which doesn’t get really, as far as I’m aware, doesn’t get measured routinely in the clinic, can be a predictor. I think you’re right about that. Yeah. The other one that I’m sure you’ve heard a lot about is hidden hearing loss or cochlear synaptopathy. So that is a definite physiologic change that’s happening due to noise exposure at the level of the synapse between the and the auditory nerve fiber. So the folks at Massachusetts, so Charlie Liberman and Karen Kujawa have shown that those symptoms that we’re. Talking about can be due to noise exposure. And then finally, the other group that I think that we’re seeing this really prevalent in is those folks with a history of traumatic brain injury. So adults who’ve had mild or greater severity of head injury are presenting with these symptoms as well. So those are some mechanisms that have been shown to help explain these symptoms. But I think we’re going to learn more as time goes on. Well, that’s a really good overview. Thank you for that. I think what a lot of our listeners are probably really interested in is some of the ways that this condition might show up in the clinic, maybe how patients describe it to their audiologist. So could you elaborate a little bit on that? Sure. I think the primary complaint that we see, and these are people who are presenting with help seeking behaviors, they’re showing up in your clinic and they’re presenting with complaints or symptoms that are consistent with the hearing loss. So it would be like your patient who presents with your garden variety sensorineural hearing loss, but then you do your standard audiometric battery and they don’t have that hearing loss. Right. They don’t have threshold elevation beyond that normal range. So difficulty understanding in really noisy environments, those really acoustically complex environments with multiple talkers. Yeah, I think just that extreme difficulty understanding and noise and when their attention is being pulled in multiple directions, that’s when they have difficulty. Makes sense. Can I just add one more thing? So my primary role is in the research at our clinic at Ohio State and one of my research participants who has this condition. She is fascinating to me. She has perfectly beautiful, pure tone thresholds within that normal range, but she describes herself as being deaf when she’s in noise. And I think that is a really powerful statement right. That her perception of her hearing ability is vastly different than what we would predict. Right. So I find that to be one of the most powerful statements I’ve heard from a patient. That’s a great example. Talk to us a little bit about the prevalence of this condition. I’ve seen various numbers thrown out there around how common this condition is. What can you tell us about that? Yeah, what I’ve seen in the literature is some estimates in young to middle aged adults ranging from about 12% to 15% of young to middle aged adults who would present with these types of complaints. So Chris Spankovich published a study based on the NHANES data in 2018. Kelly Tremblay’s data from the Beaver Dam study suggests. Anywhere from 12% to 15%. That prevalence estimate goes up when you go into older age groups. So you can get up into the age range with the adults still having good puretone thresholds, but their complaints about their hearing is much more prevalent in folks. Or adults with a history of traumatic brain injury can be as high as 50% to 60% of those individuals. We see this in the VA population. So veterans with a history of blast exposure have these types of complaints as well. Interestingly, there’s a paper from Douglas Beck and Jeffrey Danhauer from 2019, and they suggest upwards of 26 million adults present with these types of complaints. Go ahead. No, I was just going to say it’s not a trivial. The numbers of individuals that present with these complaints is not trivial. Right. And I think clinicians all around the country have patients coming into their clinic on a weekly, if not daily, basis that might have fall into this category. So it’s good to know. I think we’ve already kind of alluded to is that the traditional audiogram is not a very effective way to assess this condition. You already mentioned extended high frequency audiometry, but I think a lot of clinicians probably don’t have that. What are some other tools that clinicians can use to identify this condition? Yeah, I am a firm believer in the use of subjective questionnaires, so standardized questionnaires. We have a lot of them that have been normed and have a lot of really good reliability in clinical audiology, from that Hearing Handicap Inventory to the COSI, the Abbreviated Profile of Hearing Aid Benefit. There’s a lot of them out there. Or patient related outcome measures that can help you quantify what your patient is complaining about or the symptoms that they’re expressing. So that quantification, I think, is really powerful. We have a ton of supra threshold measures that are available to us as clinicians as well. So suprathreshold tests like speech in noise, super quick and easy with something like the Quicksin or the Words in noise test or the LISN that I use in my research as well. So they’re easy to implement, they’re easy to score, they don’t take a ton of time. So I think speech in noise is something that should be a routine part of our battery. I would also shout out dichotic listening. That is one test that routinely will show abnormalities in this population. And then if you’re interested in non speech measure. the gaps in noise tests will tap into temporal processing that can be driving some of these issues as well. Well, it sounds like you’re probably using some of those tests in your research. And that’s the next area that I want to kind of talk about with you, and that is one study that really, I think, piqued my curiosity around your research was one you published in 2020, I think it was in one of the ASHA journals, where you looked at more middle aged, younger and middle aged adults. Could you walk us through the study that I’m referring to and maybe tell us about some of the questions you were trying to address with your research? Yeah, so we’re really interested in this connection between self perception of hearing ability and actual suprathresholds auditory ability. So how do those two connect? Right? Because we would typically expect that if someone walked into your clinic who had normal thresholds or even sensory neural hearing loss, that their self perception would align with that. And then the test measures that you did. So if you did speech in noise or dichotic listening, you would expect all those three components to agree with each other. Right. But we end up with people who their self perception and their speech in noise abilities don’t align with their pure tone thresholds. So that’s kind of where this came from. Right? So we have this group of normal hearing listeners. So these were 18 to 67 years of age. We had over 60 participants. And we are really interested in if you have normal hearing through 8000 Hz or within that traditional 25 dBHL cut off range, is there a relationship between speech in noise performance and your self perception of your hearing ability? And so that was our primary research question. We hypothesized that even within that range, because 0 to 25dBHL is our normal hearing range, but that’s a wide range of thresholds, right. That we would expect to see some variability in both their perception and their speech in noise performance. And so that’s exactly what we found. We found that their self perception so those who felt that they did worse or had greater self perceived hearing difficulties actually performed worse on our speech in noise measure. Speaking of, I noticed that you didn’t use the Quicksin or the HINT, or maybe you did, but the primary measure that you used for speech and noise testing was the LISN- S. Yes. Tell us more about that test and why did you choose that one? Yes. So the LISN-S is the Listening in Spatialized Noise test, and it uses sentences so that’s the extra S on the end was developed by Harvey Dillon and Sharon Cameron down at National Acoustics Laboratories in Australia. And one of the reasons I like it is it’s a computer based program. So you have it loaded up on your computer and it presents the stimuli through headphones, but it uses binaural hearing. And that’s one of the primary metrics that I use in my research program, is tapping into binaural processing So you present sentences in a background noise, and sometimes those sentences are co-located with the noise, and then sometimes the sentences are spatially separated from the noise. So you get a metric of binaural hearing, specifically spatial hearing, and it’s easy to implement. It’s automatically scored, it adjusts the signal to noise ratio. So I think you get a lot of really great information from this test in a relatively quick and easy to administer test. And for those interested in it’s, L-I-S-N-S. Right, right. Where can people find the test? Yeah, great question. I thought you might ask me that. So it used to be distributed by phonak in the US, but that’s no longer the case. So now you can get it on a website called Sound Scouts, and that’s Soundscouts.com, and so you can get the LISN- S there. They also have a version called the LISN-U, so it’s LISN-U. It’s called the universal test. So it uses phonemes instead of sentences, so it’s less language based. I haven’t used that version of the test myself, but that is out there for it. So say you have someone whose primary language is English. You might not want to use an English based speech and based test. You could use something like this. It’s done under headphones, I’m assuming. Correct, it’s done under headphones. So how do you get spatial hearing under headphones? So they use non individualized head related transfer functions to be able to generate that spatial separation. Interesting. Well, for those that are out there, they go to the soundscouts.com and they can find the test. It’s good to know. I wanted to turn away from identification and look more at treatment. And I know back a few years ago, you published a study on the use of mild gain hearing aids for adults that were in this category, people with normal audiograms and self reported hearing difficulty. Could you tell us about that study and what you found? Right, yeah, thanks for asking. So that was the study we published in 2018. So we looked at adults who have their primary Complaint is difficulty understanding speech and noise. And we recruited them to this trial. So we put them in digital hearing aids. They were open dome receiver in the canal hearing aids. And we had directionality adaptive, directionality engaged, and we had noise reduction engaged and we applied what we referred to as mild gain. So it was amplification gain of about five to ten dB from 1000 to 4000Hz. We ensured that we weren’t exceeding tolerance or maximum output was controlled as well. We did have an inclusion criteria for these individuals. We used the Hearing Handicap Inventory, so they had to score at least 20 on that. So that was our quantification of those complaints. They wore the hearing aids. We asked them to wear the hearing aids about 4 hours a day for four weeks. And then we had them come back and we did speech in noise testing. And I was very pleased to see that. We saw significant improvements in speech in noise performance with the hearing aids relative to without. The hearing aids were really well tolerated by the listeners. So that was for majority of the listeners. We had a few who didn’t like them. So I would say that mild gain amplification isn’t going to be a universal treatment option. Right. But the majority of participants really tolerated the hearing aids well. And we had 3 of our 17 who completed the trial go on to purchase the hearing aids. So I felt really good about that, that this was something that even they got to wear the hearing aids for free during the trial. But if they wanted them post trial, they had to purchase them and they did. So I felt like that was a good outcome. Yeah, it’s one of a few studies now that show that you can successfully fit amplification on this population. So it’s good to see the evidence that that works. Yes. I’ll give a shout out to Francis Kuk. He published a study back in 2008 where he did this with children with auditory processing deficits, and then we did it with adults. And there was another study out of Syracuse University, Sing and Doherty published a trial with middle aged adults and they saw similar results to ours. Thanks for that. My final question for you, Christina, is this based on your experience, based on your research in this area, how would you advise clinicians who are working with this population? What would you suggest that they do today? Yeah, that’s a great question. I really appreciate that. Our research is trying. To spread this message that I think, first and foremost, encouraging clinicians to really just listen to their patients. So if you have a patient who comes in who presents with these types of complaints, a lot of difficulty understanding speech in noise when there’s multiple talkers, et cetera, to give those symptoms weight, right? So when they present with pure tone thresholds in this normal range, you don’t dismiss them with a diagnosis of normal hearing because threshold detection and how we function in our own environment are two very different things. Right. You’re nodding. So you get that and then, yeah, throw in that speech in noise test, make it a routine part of your clinical test battery because that is going to give you information that can help verify the patient symptoms. Right. I’ve heard way too many stories of patients who have seen multiple audiologists before. They find one who will listen to their complaints and provide them with some treatment options. And it’s a little heartbreaking to realize that they’re in your clinic for a reason. Right. They’re not there because they want hearing aids. They don’t want a hearing loss, but they’re experiencing these problems, something real going on right, that brought them in the office. Exactly. Well, that’s really good advice and it’s a great example of how research like yours can inform clinical practice. So hopefully clinicians will follow some of your advice, look at what some of the research you’ve done in this area, how we can better inform them when they take care of their own. Oh, by the way, for the listeners out there in the Show Notes, we’ll have links to as many articles as we can find that we referenced that Christina referenced today. So if anyone wants to dig a little deeper, we’ll have those listed in the Show Notes. So, Dr. Christina Roup, thank you for as spending some time with us. Hope things are well in Columbus.