All About Equipment- Episode 33 with Dr. Julie Renshaw
Today’s episode is all about audiology equipment. Now hear me out! I know this might not sound like the most fascinating topic in the world but I’m telling you, it is so, so important and interesting to learn about the equipment that we use and how we use it to get information about hearing, about how our ears work and which part of our ear has different things going on with it. And you know, when you’re a parent and you’re bringing your kid to the audiologist, they’re not just shaking a rattle and seeing if the kid responds. That might be the first step to just see if there’s any kind of gross awareness. But we actually have very precise and very complicated and technical ways that we’re checking different parts of the auditory pathway in order to get information about your kids’ hearing, or about your own hearing for that matter.
So, here’s the conversation that I had with Julie Renshaw, an experienced audiologist who shared with us not only the important role of the equipment, but absolutely the necessary understanding that audiologists need to have in order to understand what that equipment can do and what the results mean and being able to interpret all of that. So, I think this interview, like most of the episodes here, are for both groups of audiences that are listening. Many of you are students, students of audiology, of speech pathology, of communication disorders and I think there is a lot in this episode that you’ll find really relevant to your studies and to the practice of our profession.
It’s also specifically geared for families who are dealing with this, who have been on the side of the appointments where you are watching your kid get stickers all over their forehead. So, we talk about that in the interview and I really think that it’s going to bring you some comfort and some value to know that it’s not a weegie board but it’s an ABR. We explain what all that equipment means. So, I hope you’ll love this episode as much as I enjoyed talking with Julie.
Thank you so much for being a listener to the All About Audiology podcast.
Let’s jump right into it!
Welcome to the All About Audiology podcast. I’m your host, Dr. Lilach Saperstein and today we’re talking all about instrumentation. It might sound a little bit boring and you might be thinking, ‘Why do I care about the equipment used at my audiology appointment?’. But wait, you’re in for a surprise! It’s actually very interesting. At least I think so.
I also have someone very special with us today who is very experienced, has a lot of knowledge to share with us about instrumentation. Julie Renshaw is going to tell us why this is so important for our practice. I hope we have listening today, parents and audiology students and people with hearing loss. That runs a gamut of the audience and I think everyone can benefit from the conversation we’re going to be having.
LS: “Welcome Julie!”
JR: “Thank you so much for having me. I really appreciate it.”
LS: “Why don’t you tell us a little bit about your background and your current position.”
JR: “I’m a clinical audiologist for 37 years. I worked for Riley Children’s Hospital for about 20 years of that. So, I was involved in all different aspects of audiology as part of my role there. And over the last 15 years, I left clinical practice and have been representing all things related to equipment for hearing and balance assessment. I do not represent cochlear implants or hearing aids specifically, but I do everything else related to those assessments.”
LS: “Okay. So, tell us a little bit about why instrumentation is so important to the practice of medicine in general and for audiology specifically.”
JR: “I think instrumentation is so important because it’s such a critical element of the diagnostic process. So, I’m thinking of my hearing impaired children, without proper instrumentation, identifying their hearing loss, quantifying it and helping the families make that next step is really impossible. I think everything in medicine today depends on equipment giving us a proper diagnosis. It is so important to listen to families and I always believed that some of the best information you can get is by saying, ‘How do you think your child hears?’. We’re such a technology driven society so I think that the next step is often relying on high end diagnostic equipment to get the most accurate starting point, whether it’s for a cardiac problem, a hearing problem, a vision issue, all of those things require technology and good equipment.”
LS: “For sure. I think that one of the simplest things to understand is that even using headphones already is such an amazing tool because you’re getting information from right ear vs. left ear, which you’re not getting if you have a kid in front of you because you don’t know if you’re getting both ears or one ear. Even that’s like a simple thing that you think, ‘That’s obvious and we should use those.’ You need to have well-calibrated and equal right and left earphones or headphones. That’s one of those things.
Also, I remember we had a professor when I was an undergrad. He used to say that if someone called the tympanometer or the audiometer the “machine”, he would say, ‘It’s not a machine, it’s an instrument!’
Instrument is something that you use to measure things and like you said, to quantify, so, it gave me a lot of respect for all of the things that need to go into the audiology environment in order to make everything else happen.
So, the first equipment that a lot of people interact with is just by the screening, the newborn hearing screening. Someone comes in or it’s in the nursery and someone is putting these stickers on their baby’s head with all these wires. So, they might be overwhelmed about what’s going on, what is this whole contraption. So, let’s talk a little bit about ABRs and what electrodes are used for, how does that give us any information about hearing. Let’s jump in to ABRs which stands for Auditory Brainstem Response, or in other parts of the world, it’s also called BERA, (Brainstem Evoked Response Audiometry). It’s all the same thing.”
JR: “I think you bring up a really great observation initially which is hearing screening in the nursery is so critically important, yet it can sometimes set the wrong tone for parents and the identification process because the screeners are often very well-intentioned, private screeners or nurses or volunteers. Their role is not to bring the parents into that testing in a way that often facilitates confidence, understanding about what’s happening. I’m a huge believer that the parents being a part of that process is so critical. I don’t think that we can undo the way hearing screening is done and I think it needs to be done. It’s so important but I think that when there is a need for follow up tests, that it is imperative that we totally change that dynamic of their understanding of what’s happening.
In a nutshell, you asked me to kind of review what is happening with the placement of electrodes. Technology is everywhere in our lives and I think that families are, in general, again, very comfortable with how maybe an ECG works with the heart. And our body is just full of potential energy that is happening all the time. Positive and negative electrical energy that is going on on the surface of our skin, we can measure that. And we do it with measuring the heart function. We do it with a lot of electrodes placed on the scalp for an EEG and I think people are more familiar with the fact that electrical impulses are just part of our makeup.
What we do with an ABR, we actually do a far field recording and a surface recording. Because, basically, we can’t get down to that hearing nerve which is the ideal. If we could put an electrode right on the hearing nerve of that baby, we’d know exactly what they hear. But that’s not ever going to be feasible. Maybe it will in, you know, twenty years from now. But right now, we’re forced with measuring far field away from that nerve by putting critically placed electrodes on the scalp.
We know there is all this electrical energy going on, so what we do is that we have to average that out, signal averaging. Get rid of all that, we’re going to call that, noise. That’s just your body activity. Your body electrical potentials. And we’re going to look at what happens in a very narrow window of time. Actually, twenty milliseconds, which basically is saying, I’m putting a sound in this baby’s ear and we’re going to see what happens as it goes down the eighth nerve and the brain stem. And we’re going to measure if that nerve is saying, what I like to tell my families, ‘I’ve got it, I heard it!’ And it’s going to give a peaked response, it’s going to show a pattern and that means that that baby heard that sound.
So, the way we accomplish this is that there are a lot of sounds going in to the ear that we are averaging. So the baby is going to hear a sound, and after every one of those clicks, we’re going to look at twenty milliseconds of activity. If a signal processor, every one is familiar with the averagers and processing now, we have a processor on every desk and computer. We’re going to use a processor like that to take that information and we’re going to synthesize it all together and filter it and amplify it and get rid of all of our regular body potentials and see if that hearing nerve is responding. So, when they come in to test your little baby in the nursery, we’re putting on the surface electrodes and we’re averaging and we’re putting sound in there and we’re making sure that that signal is getting through to the brainstem.”
LS: “Excellent, that was a very good explanation. Again, if you just start from the beginning, which is what you did, there are these potentials, these energy changes that are constantly happening all over our bodies. We’re just finding a way to measure it and access it. So, that’s why this instrumentation is really important. It gives us like, this window, something that we couldn’t get otherwise. Not only that, we can also use ABR for other things, not only for babies. What else do we use ABRs for?”
JR: “So, when you have auditory brain stem evoked response equipment or brain stem evoked response audiometry, you can use it to assess hearing, which we just discussed, by changing the intensity and changing the stimuli that are presented. You can also use it as an assessment of neural integrity. So, let’s say there is a concern that someone might have a problem on their auditory nerve or their vestibular nerve that is causing balance (issues). We can look at the timing characteristics of the nerve to determine whether or not there could be a problem there that would prompt them to have a scan to make sure there is nothing going on in their brain stem area. It could impact their longevity of their life. One of the things that we can do is that we can use from a hearing perspective. [Another thing is that] we can use it for a neural perspective.
Also, if you have a system that can average responses, which we know that that’s the heart of this kind of equipment. It’s an averager. You can also use it to make balance assessments by doing what’s called, looking at a potential in the cochlea called the summating potential in electrocochleaography. You can use it to look at a myogenic potential called the ‘Surgical vestibular evoked myogenic potential’ or the ‘Ocular evoked myogenic potential’ (cVEMPs and oVEMPs) which all look at different parts of the balance pathway versus the auditory pathway and how all of those can come together to give diagnostic information.”
LS: “Yeah. So, in the clinic that I work in now, we have this room. When you walk into the room, there are like four different computers and wires everywhere and lots of stickers and gauze and some of this stuff that you have to mush on your skin, and it’s just I think, so important for patients to come in and be able to say, ‘What is happening? Why are we doing this? What is the point of this test?’ What are some of the things that you would recommend for audiologists to say to their patients, or that you would want patients to know when some of these kinds of testing are going on, when someone is preparing for this kind of testing, both sides of that, the audiology side and the patient side?”
JR: “Well, I think that the patients’ side is so much more educated than it was when I started practicing audiology so many years ago, because all it takes is a Google search and the test that you’re going to have. You can see YouTube videos about it, you can read about it, you can get exposure to it. I think, though, what we can do…
LS: “Podcasts about it, hahaha!”
JR: … podcasts about it. So, I think that it’s still critically important that the one-on-one when you have that opportunity to meet with the patient, that you don’t assume too much that they have read or too much that they listen to, because I think you want to clarify and make sure that they’re comfortable with what is going to happen to them in this experience. So, I know that my passion for many years was making the pediatric ABR experience something that was really, really meaningful to parents. And I never wanted it to be, to use a quote from the Wizard of Oz, “Pay no attention to that man behind the curtain”.
Because, I think that far too often, I’ve had parents from other facilities come, and not that I am in any way casting dispersions on what happened, but they would say, ‘We went in this dark room and we came out and they said my baby couldn’t hear.’ I never, ever wanted that to be the case with my kiddos, so, what I would do is, again, depending if the baby is asleep, sometimes you have to work quickly in the beginning. But I always would have a printout of what they would see on the screen of what would be ‘normal’. I’d let them listen to the clicking sound or the tone burst at all the different levels so that they had a sense going in that this is what is happening. These are the levels, and this is what we are watching for on the screen. They hold it in their hand, they listen to all the levels and maybe watch it with me. Sometimes, they talk, and I talk to them during it.
Sometimes, at the end, what I would like best of all, is when I turn around and they tell me, ‘They couldn’t hear below 65’. ‘That’s where we are on the screen, you’re right.’ They’re part of the diagnosis, they are part of the test, they are part of the assessment. It’s not that my back is to you and in the end, I’m going to turn around and show you a piece of paper and this is it. And then at the end, again, we listen to the exact level that they can hear. And then they would hear the level that they could hear. ‘Oh, I could hear at 20, and they can’t hear it there?’ No. This is where we stop and then you have commitment and you have knowledge and you have buy-in by the parent and like I said, nothing made me more satisfied, as hard as it was, to turn around and have them (the parents) tell me the result before I could show it to them.”
LS: “That is amazing.”
JR: “That’s what I like to do because I want them to be a part of it. If you know, because I can tell you’re passionate about pediatrics, if they walk out of that room not feeling like they understood what happened, and what that means, it is going to delay so much of the intervention, which is so critical for these little ones. You know, you can’t wait until they are two years old. If you wait until they are two, they are never catching up. There’s been a bunch of research about that. It’s not that you can’t have good intervention, but the two-year-olds aren’t going to wait for the four year olds. No one is going to stop advancing. So, if you get two years behind, you will never close that gap. You will never close it.”
LS: “Yeah, it just keeps getting wider as they grow?”
JR: “Or you can maintain it if you catch up, but they’re never going to wait for you. If you have the little one, the four year old, and you tell them, ‘Don’t learn anything now for the next two years until your brother catches up’. This just doesn’t happen.”
LS: “Hahaha, I mean this is such a great pediatric tip in general, like a big protocol. Because I’ve heard about this idea for having parents come in to the test booth and doing sound field testing so they can be present hearing the sounds that perhaps their child is not responding to at various levels. And they could understand it because they have heard and seen what is missing there. Which from the earliest ABR, to do that with them, that’s something that I’m going to consider now and include. It is very much like this: you stay quiet for half an hour or forty five minutes and keep that baby sleeping. We’re in a rush too, so we’re always balancing those two things in the appointment. That is a great idea.
Sometimes, babies are screened with the ABR screening that we have been talking about and other times they use the OAE screener, the Otoacoustic Emissions screener. So, how is that equipment different? What does that tell us about hearing and why are there some places that use one or the other?”
JR: “So, when the Joint Committee, when they first were deciding to implement universal hearing screening, they approved both Otoacoustic Emissions and the ABR. And then, as we learned more and more about how this screening process worked for babies identified with hearing loss, and babies who are missing, that had problems with their hearing, that philosophy evolved over a little bit of time to a little bit different best practice standards. So, to step back, let’s talk about the differences between the two.
As we talked about with ABR, we are measuring from the sound entering their ear canal through that middle ear, through the inner ear, through the snail-shaped cochlea to the hearing nerve and then we stop at the brain stem level. We don’t get all the way up to how they are using that sound. But we get a lot of the pathway of auditory audition looked at.
Now, when we do OE, it’s a faster test. It’s quick. There are no electrodes put on the scalp. What happens is the sound does have to go in an ear. You have to have the sound going into the ear, but it only looks at the response to the level of the cochlea. It does not involve any neural processing of the sound by the auditory nerve. So, basically, this sound goes into the cochlea, generates a response back, which picked up with a little microphone sitting in the ear canal that’s measuring this response.
So, how are they different?
Well, they both look at the auditory pathway. One goes, let’s just say for argument’s sake, halfway up and the other one goes three quarters of the way up. Nothing goes the 100% of the way up, which would be the brain. None of them say how the brain is using that sound. Our goal at this point, is that we have to just make sure that the sound is getting there. We only can check that it’s getting halfway with the OAE, and three quarters of the way with the ABR. So, why did we approve the OAE?
What we found is that most hearing loss happens in that first half, we used to believe almost all hearing loss happened in the first half of the pathway. So, we were going to catch all the babies right? We weren’t going to miss any babies. But then we found, like anything that you do, you do more and you get smarter. And you look at all these babies that are being screened now. Universal hearing screening, we’re testing a lot of babies and then we see babies that were two or three and we’re like they passed their newborn screening but they’re not hearing like they should, they’re not functioning like they should, their speech and language isn’t developing like it should.
What happened? Why did we miss these babies? Did they have a delayed onset of hearing loss that came on after they left the nursery? Well, we found a large percentage of them where that was not the case, that there may have been a problem in this last quarter that we’re measuring, that first half after that nerve part. So, we thought, well, who needs to have that test which goes all the way to the nerve, the AVR part and we decided our vulnerable babies really do, our babies in the special care nursery. These babies neurologically can sometimes be compromised. They’re not maturationly where they need to be, we need to follow these babies and all aspects of their life. Little preemies are followed not just for auditory, but their vision, everything. And we decided, okay, let’s kind of step back on our joint committee and say, ‘If they’re in the special care nursery, let’s just not check them halfway. Let’s check them as far as we can as a screening method,” which would be the ABR.
So, I think the trend is, and I think eventually, and this is just my two cents, not any recommendation by the Joint Committee at all, is that eventually they will do ABR on all babies. That’s kind of my goal, that all babies would have an ABR. But at this point, well babies, will have the OAE in some hospitals and special care babies will have ABR and some hospitals screen all with ABR and some little hospitals that don’t have any special care nurseries, first second or third tier or whatever how many tiers there are now, I’m probably out of touch on that. There’s probably six tiers of NICUs. Those babies, those hospitals, they only have the OAE, just to check the level of the cochlea. So, I hope that answered your question.”
LS: “Yeah. Earlier this year, I started working at a hospital here in Israel. And we have the six month follow up for babies who were in the NICU for any reason, for premature or anything you know, any of those special considerations. And they all have this six month follow up appointment, where we’re then able to do some sound field testing, OAEs, tymponametry. And just some gross evaluation of their hearing as well with little toys, which is just so delightful, because the parents can see we’re shaking a rattle, and they turn their head and it’s very cute, even though I always tell them, ‘That’s just for, you know, gross, big general tests, like are they attentive to the sounds,’ but everything else fits in a little bit more information. But the cutest thing that happens is because these appointments are made six months ahead of time when they’re coming out of the NICU, it always becomes this little reunion for all the families that were there together. And it’s just so moving and so heartwarming to go into the waiting room and call the next one and everybody’s just schmoozing and catching up on how their babies have been. That’s not an easy experience. And I think when parents go through that, find them as a group or twos and threes, it’s really beautiful. So, that’s my Wednesdays.
So, we’ve touched on a lot of the different instruments and why they’re so important for audiological diagnostics and evaluation of hearing. So, what else would you like to share with our audience? Anything about how to deal with a diagnosis or we have many, many students as well who listen to the podcast, so you can address them as well?”
JR: “Okay, I think one thing from an instrumentation standpoint I’d like to add is that technology has improved. The ABR when I started doing it, thirty seven years ago, we mostly used the click stimulus. And now, I think what we’ve seen that’s improved with the diagnostic techniques as we have improved stimuli, now we have for ABR, the chirp stimulus, the LS chirp, and we have the neuroband chirp in lieu of tone bursts. So, we are constantly refining the information we can get, which improves the ability to fit hearing aids more accurately.
We also have second generation of ASSR testing, Auditory Steady State Response testing. And again, this is allowing the testing to be done more quickly, which is much less stressful on the families. And you can do both ears at the same time. We actually have newborn screeners now that actually do simultaneous testing of ABR as opposed to sequential, which is the right ear and then the left ear, even though you hooked up both ears, it was doing them sequentially, you know, we can do it simultaneously.
So, I think technology is improving on our ability to get a more accurate picture of hearing. I think some other interesting things have developed in the balanced realm. I think that the advent of doing vestibular evoked myogenic potentials has been huge. It didn’t used to be something that would fall under the auspices of audiology that much. It’s been a new development. And I think what’s really interesting about it that people don’t always, maybe for the students out there listening, appreciate is that this is all about pressure stimulating the vestibular system. It’s not based on anything auditorily, which is interesting because you’re putting a loud sound in their ear. Your immediate reaction is, ‘oh, well, it’s the sound that they’re responding to’ when in fact, it’s the pressure disturbance in the vestibular system. So, you can have someone who is deaf that can have a vestibular evoked myogenic potential. So, I think that’s an interesting aspect to keep in mind when students are learning about vestibular evoked myogenic potentials.
So, I think that that’s been a really exciting area for me, because it wasn’t something I had done clinically before. So, I’ve appreciated adding that to my repertoire. And I think all the time we’re learning so much more about the balance system. I think we are always advancing on what we know about the auditory system and how it works. But I think from a diagnostic perspective, for students coming out of schools now, they can’t learn enough about balance. I think that the techniques, the diagnostics, the equipment, whether it’s Computerized Dynamic Posturography, whether it’s a VHIT, whether it’s the testing, this is just an area that is going to continue to grow. Because as we know, fall prevention is a huge initiative in our country, and we have an aging population that is going to continue to have more and more vestibular issues.
So, if I was a student now, I would focus on balance related instrumentation, learning more about that. I think our training programs do a great job with audiograms, sound build audiometry, ABR, because that’s so important. OAEs absolutely, tymponametry… But the balance program just, I think is going to continue to grow and I think if you’re an audiologist who can do all of those things comfortably, an audiologist within their scope of practice can do the diagnosis for that. They don’t, in the United States, I shouldn’t speak for other countries, so, you don’t have to have the involvement of ENT to make the diagnosis of neurology, you can actually do this testing and do the diagnosis. And I think that’s critical to us as a profession. And I think that it’s critical to the population, we can get more direct referrals for people that are having balance problems, that are having a fall risk. So, I think that element needs to really be enhanced in in what people seek out and what they’ll learn about, because I think it’s fascinating and I think there will always be a place for someone who can assess someone’s balance.”
LS: “Exactly. I was just having a conversation on Instagram today with a student who sent me a DM and said, ‘Hey, what do you think about PSPs and hearing aids that you can get for $50 off the internet, and the role of Audiology, is it still a great field to go into?’ And I said, ‘Wait, wait, wait, wait, do you know what audiologists can do? So many things! And you know, showing her all the different fields in audiology. So, I do love talking to students, I think everything you said is exactly right to get as many skills as you can within all the different fields within audiology, because it’s, it’s really so varied.
And the other thing about what you said about the pressure, and how, like something that really excites me about instrumentation, is that it really forces you to go back to the fundamentals, you have to understand that sound is sound pressure, and physically moving things within the environment through sound waves. And, you know, going back to the different parts of the pathway, you have to be really immersed in that when you’re using the instrumentation and it can’t just be a technician level like “just pressing buttons”. You have to actually have to know what do those buttons do. How does this system work? What’s the circuitry? So, there’s a lot of that that’s always fascinating to me and why it’s something I just want to share with the world. Haha.”
JR: “We appreciate you doing that.”
LS: “Julie, thank you so much for joining us today. If anyone would like to contact you with any further questions, is there a way, the best way for them to do that?”
JR: “Yes, they can. They can certainly email me at the email address that you have, which is Jren@Gordonstowe.com.
LS: “And you’re on LinkedIn as well? They can find you there?
LS: “Awesome. Thanks again!”
Thanks again for listening to the All About Audiology podcast. I can’t wait to hear what you thought of this episode. What other questions you might have about the various equipment we use in audiology. I actually received a DM from one of you on Instagram who asked me to talk about REM, which is Real Ear Measurement. That’s another kind of equipment and software that we use when testing hearing aids and when making sure that the hearing aids are programmed adequately. And that’s a really interesting technology that lets us know that what the hearing aid is putting out, the sound coming out of the hearing aid, is exactly right for each person’s precise ear shape, the length of their ear canal, the way the hearing aid fits in their ear. So, it’s a very specific and personalized kind of fitting. We didn’t discuss that too much in this episode, it was more about diagnostic equipment.
But I will send you over to Listen With Lindsay on Instagram with Dr. Lindsay, who does a lot of simulations of what hearing loss, what various kinds of hearing loss might sound like using the REM equipment, the real ear measurement of the verifit, so definitely check that out if you’re interested in more and 100%, send me your questions. Send me a DM on Instagram @allaboutaudiology podcast. It’s so, so fun for me to interact with you guys and learn about your journey, your learning, your study, your process, because that’s what this is all about. It’s about feeling like you have support. You’re not alone and there are other people in our community, you know who you can connect with and who can understand what you’re going through, whether you’re a student, a parent, or you yourself are struggling with hearing loss.
So, just know that I’m here for you. And the All About Audiology podcast is my gift. My labor of love for you out there. Stay tuned for future episodes.