Paediatric vestibular assessment (Rotational chair focus)

In the video we will begin to think about pediatric vestibular assessment and the role of the rotational chair in this process. We are delighted to welcome back Dr Violette Lavender to present on behalf of the Interacoustics Academy. In this video, she presents a variety of tips and tricks on how to test infants with balance disorders with a strong focus on the rotational chair.

You can read the full transcript below.

Table of contents

• Introduction
• History of pediatric vestibular testing
• Future of pediatric vestibular testing
• Development of the pediatric vestibular system
• Developmental reflexes
• How does the human vestibular system work?
• Vestibular reflexes
• Motor milestones
• Potential signs of vestibular loss
• Which children are affected?
• Goals and expectations of vestibular testing
• Case study
• Update on a previous case study

Introduction

Hello everyone, my name is Violette Lavender and I'm an audiologist at Cincinnati Children's Hospital Medical Centre in Cincinnati, Ohio. I hope this presentation reaches you all well, and today I'm going to be talking about pediatric vestibular assessment.

And I'm your biggest cheerleader. So I'm going to be telling you that I'm cheering for you. And really, truly anyone can do this. This is something you all can do. And I know most of you have arrived here today in the context of having a child on your schedule unexpectedly and maybe concerned about how to test that child.

Or maybe you're developing a clinic, and you want some more information on how to work with children. So today, I'm going to be talking to you a little bit about how to test those children no matter what age they are. And we're going to have a special emphasis on rotary chair today.

So rotary chairs, a big piece of our test battery, and it is a really important piece to our puzzle. So I'm going to be talking about how we use that in the context of working with little ones. And if you enjoy this picture, this vintage picture, you can find me...here I am circa about 1992 or so.

Now, I'm all grown up, and we work with a wonderful team at Cincinnati Children's Hospital. So I just want to share their faces with you. So you know that I'm not alone. And we've been doing this, we've been open for about 14 years or so... it's been a great adventure, working with kids in the pediatric setting.

History of pediatric vestibular testing

Pediatric vestibular testing hasn't always been on the map, so to speak. But now we actually have quite a lot of attention given to pediatric vestibular testing, for example, there are some AAA guidelines, I can tell you that those are upcoming; I'm on the committee and we are writing some guidelines on how to test kiddos when they come into your clinic.

There are also two editions of the Manual of Pediatric Balance Disorder textbook. And that's very exciting now that we're already on the second edition. There's also some international attention given to what is called a vestibular newborn screening.

So if children are identified with hearing loss by ABR through their newborn screening, and then through follow up, early on, they're able to get cVEMP, for example, testing done to find out if there's also some concurrent vestibular anomalies as well.

And the work we can't talk about without discussing some of our predecessors. And so in the 1980s, there was some work by Dr. Cyr at Boystown, where he was looking early on a vestibular test battery for young children.

And in the 1990s in France, Sylvette Weiner-Vache was also looking at some of the syndromes that were associated most likely associated with vestibular loss, and there were some good papers that came out of that the early 2000s.

We started to see both some rehab, some rehab strategies listed in the literature, but there was also a modern pediatric test battery as the equipment started to progress.

So in terms of modern rotary chair, some cVEMPs were coming out as well that we were able to test young children, even infants, and then people were using posturography.

And then finally, as of late, in the last 10-15 years, there's been a lot of attention given to things like oVEMPs, cVEMPs and vHIT, and our test battery has really become finessed, and there's been a lot of work given to pediatric vestibular testing in general.

Future of pediatric vestibular testing

And when we look to the future, what do we expect for what keeps that pediatric vestibular testing on the map? One would be we'd really like to see peer reviewed vestibular rehab outcomes. So there's been some early work on pediatric vestibular rehab, but there's not a lot of progressive work. So we'd like to see that continue on into the future.

We'd also like to see improved equipment. So as we move forward, we'd like smaller goggles and those types of things. And those are on the horizon, I understand.

We'd also hopefully...I know everybody in the vestibular world is interested in a CPT code for vHITs specifically. And that's specifically to the United States, then, of course, in the United States, we do not have FDA approval for the touchless vHIT system that I know in Europe, and across there, there is approval for that. So that's super handy in testing the young children as well.

Development of the pediatric vestibular system

So I want to talk to you, since we're going to be talking a lot about vestibular assessment for pediatrics, and in addition, especially rotary chair, we really want to understand the development of not only the vestibular structures, but also the vestibular reflexes as well.

So when we think about development of the pediatric vestibular system, it starts in utero. And so early on, at only the 3-to-6-week development, we're already seeing the utricle, the saccule, the endolymphatic duct and sac and even the semicircular canals start to emerge. This is one of the earliest systems that is going to start to emerge in utero.

At 9 weeks of gestation, we're already seeing hair cells and end organs, and at 16 weeks, the linear receptors in the macula are also starting to form and develop. And by 20 weeks, we're also seeing -- this is very cool -- we're seeing the vestibular portion of the 8th nerve be myelinated.

And this is before any other nerve, including the auditory portion of the 8th nerve. So this is one of the earliest cranial nerves to be myelinated. By 23 weeks, we're also seeing the angular receptors start to form. And finally, by the 25th week of gestation, our vestibular system is basically complete, which is very miraculous.

Developmental reflexes

And as children are born assuming they are term babies, we're going to see a certain number of developmental reflexes. And those definitely depend on the vestibular system. And early on, when I started our work, we were chatting with the physical therapist, and a lot of the physical therapists didn't even realize that the developmental reflexes that they see in infants are related to vestibular receptors.

And since the vestibular receptors are in place at birth, you can imagine tipping a baby back elicits a response. This is very neurologically driven to because the whole system is a pathway. Vestibular does not act on its own, it reacts with the entire system.

Moro reflex

So for example, the Moro reflex, which is present at 30 weeks gestation, we should expect to disappear by 3 to 6 months of age. Some people call it like the parachute reflex or it's, it can be when you tip the baby back, their hands splay out.

We also know that it can be abnormal in some babies who have neurologic issues such as cerebral palsy, or neonatal abstinence syndrome. Those children might have hyper exaggerated reflexes, and it might not even go away after a certain period of time.

But in the case of children with no vestibular input, this reflex may be totally absent. And I'll show you what it looks like. I'll play it one more time for you. And you can see when she was tipped backwards, her hand splayed outwards. And they even started to call in as well as she was being picked up.

So that is a protective reflex that through nature that we have. And some people think that when back in the caveman days if a child was to fall off their mom, because they had to do so much traveling across continents, that they needed to be able to hold on or alert the mom that they were falling off.

But I have had it in the context of some of our kiddos who were born with no vestibular system. Their moms reported that when they tried to nurse their infants, that when their infant would fall off, that they didn't even know they were falling, and they would just continue to fall like a roll off.

And so she said that when she had other children who were born hearing, so this mom had two children, she had a group of children who were born with Usher syndrome, and a group of children who were born normal hearing.

And she said when the children who had normal hearing, she knew right away that they had perfect hearing, because when they would fall off, they would have this reflexive "I need to get back on". So it's really interesting from the context of the early days when she was nursing the children, even before they had had the newborn screening, she had noticed whether or not they have this reflex.

Head righting reflex

We also see the head righting reflex. So the first developmental milestone a baby really even has to do is pick up their own head. And so the head righting shows us that it can be balanced between the two sides and forwards to backwards. So especially if they were to fall, they would know to pick their head up. This typically appears by 4 to 6 months.

And in children with vestibular loss, it might be absent. But in some cases, especially children who have congenital cytomegalovirus or enlarged vestibular aqueduct syndrome, it may be asymmetrical because they have asymmetric firings on each side.

So what we'll do is we'll tilt the child 30 degrees from the vertical plane, and you'll actually see a correction to remain midline. So here's what that looks like. Let's take.. Mama. Mama. Where's mama? Where's mom? Ready, set, go! Oh, good job. Ready? Let's see. Where's mama? One, two, three, ooh! Good! One more.

Her little hearing aids are so cute. Good job. There you go. So what you could see is that when we tilted her down in the different planes, her head wanted to remain midline.

Vestibulo-ocular reflex

Another developmental reflex is the vestibulo-ocular reflex. So we're all familiar with this when we think about rotary chair, the vestibulo-ocular reflex is present basically in the first two weeks of life, you'll see the Doll’s Eye reflex.

So you know whenever you're playing with that baby doll, and you tip them back and their little eyes closed. But also when we rotate the eyes, when we rotate the baby, and everybody rocks their baby, you'll actually see the eyes go opposite of the stimulus. And that means that vestibular receptors are working.

So the very mature VOR starts to really be working at about 3 to 4 months. And we should be able to see nystagmus when we rotate the babies and here's a little video of that. So cute. That's one of my co-worker's babies. And so it's nice to have co-workers that have babies right now because I can call and phone a friend and get a video if I need one.

How does the human vestibular system work?

So the human vestibular system works by using the eyes, the information from the inner ears, and finally the proprioception which is through the muscles' response and also the feeling in the feet. And all that gets integrated at the level of the brain. So through the vestibular nerves up to the vestibular nuclei and into the brainstem and cerebellum.

And what's unique is that it doesn't just stop there, the brain...so where we just left off...has a reflex down what we call the vestibular spinal tract. And we are looking at also the vestibulo-colic reflex. So think of the neck, the back, the torso and all the way down to the feet.

There are receptors down there so that we don't fall down. So that helps us keep our balance. We are also looking at the vestibulo-ocular reflex track, and this helps us keep images steady whenever our head is in motion.

Both of these reflexes are very important. And since we don't have a great way to test the vestibular system directly and on its own, we are very much looking at these reflexes to say whether or not the vestibular system is appropriate.

Vestibular reflexes

So onto vestibular reflexes.

Vestibulo-colic reflex

The first things, like I said, that babies do is learn to hold their head up. And so when we look at the vestibulo-colic reflex, we want to know that while the body is in motion, that the signals are sent from the otoliths because they detect the motion, and they're able to say, 'Uh-oh, we're moving' so they tell the brain which tells the muscles in our neck to hold the head steady. So that way we don't have this bobblehead thing going on.

This is the little girl I showed you guys last year if anybody was there present for my case, but a little girl who had a unilateral loss after a cochlear implant. And you can see if you're just looking at these two pictures that she has quite the head tilt after her cochlear implant. So because she now has asymmetrical input from her two inner ears, that is causing her to have an asymmetrical head tilt, or in this case torticollis.

Vestibular spinal reflex

Next, we're going to be talking about vestibular spinal reflex. And this is important because the receptors work that when you are feeling a perturbation or you're moving, your inner ears sense that, tell your brain, which turns on muscles in your postural control muscles to help keep you balanced. This continues to mature into your teenage years.

So at first you have easy things you need to do like learn to walk, which progresses to more difficult things like learn to ride bikes, and finally even skateboarding, or snow, snow skiing or waterskiing or even rollerblading. So all the fun things that kids get to do.

Obviously, you don't come out of the womb knowing how to ski down a mountain. But it takes time. And as that reflex matures, you get better and better at it as well.

Vestibulo-ocular reflex

And finally, and this is the part that we care about a lot for the vestibular testing is we want to have good vestibulo-ocular reflexes as well.

So when we think about this, we're going to have vestibular receptors that work in tandem with your ocular muscles. So that while your head is in motion, you can keep a clearer vision. And anything that's absent.. an absent VOR by 10 months of age is pathological.

And remember I told you it starts early on by like 3 to 4 months. If it's still not there by 10 months of age, you should definitely consider that to be pathologic.

Motor milestones

I always like to give you guys a chart as to what to expect because we're really, when we talk about, for example, hearing impaired kids and vestibular loss, we really care about: are they meeting their motor milestones?

And so just as a quick reminder, especially with walking, everybody always asks me 'Well, how late is too late to be walking?' We would say that two standard deviations so especially--oh, I'm so sorry—two standard deviations for walking, especially in the States we use 16 months.

So right around 16 months if they're not walking, that's considered to be outside of two standard deviations, and that would be considered cause for concern or when they would send them for additional physical therapy in the United States.

That being said, we did a study a few years ago where we looked at kids with enlarged vestibular aqueduct, and in general in our control group that we looked at who had normal hearing. They on average walked at around 12 months of age, and our children with enlarged vestibular aqueduct syndrome typically walked at around 15 months of age.

That also is supported by work that Kristen Janky has done at Boystown. And she said that children with hearing loss who are not walking by like 14 and a half months should be considered at risk for vestibular loss.

So usually if kids have hearing loss, and they're not walking by 14, 15, 16 months, we should definitely be considering them for at risk for having a vestibular loss as well.

Potential signs of vestibular loss

And what are the signs of vestibular loss associated?

Torticollis

So when we're talking about our little, teeny tinies, the big thing that we'll see right off the bat is torticollis. So not all babies born with torticollis are going to have vestibular loss. But if they have a hearing loss, and they have torticollis, we should be concerned about vestibular loss.

Hyperextended limbs

Another thing we might see is hyperextended limbs. So some of our babies who have no vestibular input are often diagnosed with hypotonia, meaning they have very low muscle tone. And sometimes we'll even see that that they want every part of their body to touch the floor as much as possible or touch their mom.

And so will often see even their toes are wrapped around their mom just to get that input. Because they don't have the inner ear input, they're making up for it with their proprioception. And so we'll see even their little toes curl around their moms, every single part, they'll even put their faces against their mom's faces when they're holding on. So darn cute, but that can also be a sign that there is some vestibular loss.

’Floppy necks’

We'll also-- the moms will say floppy neck. So when they go to pick them up, they say their heads are very wobbly early on, and it's harder for them to keep control. That kind of goes along with torticollis, but maybe more floppy, more hypotonic. We'll see delayed motor milestones, of course.

Difficulty with surface transitions

And then parents will tell us they really fear transitional transitioning between surfaces. So if they're walking on concrete, and it's hard, and then they switch over to go to like mulch or sand or gravel, they start to fear that or they get more imbalanced when they switch. They don't like those surfaces.

Dislike of unstable surfaces

So it's not just that they fear the transition, but they really don't like being on compliant surfaces. Why is that? Well, if you're depending on your proprioception cues to be solid and stable, those surfaces are not stable. And that makes it more difficult for them to walk on.

Nervous about ambulating in low light

They might be nervous about ambulating in low light. Again, when we think about the vestibular system being eyes, feet, inner ears, if you don't have the inner ear sense, you really rely on your vision. So anytime we take away the visual piece, it really makes it difficult for them to walk around or get to the bathroom in the middle of the night when they're little.

Which children are affected?

But who's affected?

Children treated with ototoxic medications

So I've already mentioned children with hearing loss, but we also need to consider that children treated with ototoxic medications can be at risk. Then kind of who else?

Children with congenital CMV

There's a broader category here of children with congenital cytomegalovirus, who do not have hearing loss. So we've actually had a handful of these kids come in over the years. And especially now that we're looking for congenital cytomegalovirus. We've had kids come in who have totally normal hearing, but they also have vestibular loss. And so that's been very interesting for us.

Children with head trauma

We also have children who've had head trauma, and they can get an inner ear concussion. And they can also have central nervous system issues with vertigo and balance.

Children with meningitis or other systemic infections

And then of course, any type of infection. So you know, it'll be interesting to see, I think there's some early data coming out on COVID-19 affecting vestibular, the vestibular system as well, I think we've seen that in our clinic, but meningitis or any other systemic infection, but on the other hand, so those are all the kids that we think about have balance issues.

Children with vertigo

But on the other end, we also have kids come into our clinic with actual vertigo.

So these might be children who have things like migraine variant or something similar, like benign paroxysmal vertigo of childhood. This is not BPPV--everybody always asks, but rather they think it might be related to a precursor to migraines.

There's also something called benign paroxysmal torticollis of childhood. This is where you have spells where suddenly you get locked into something where your head is asymmetric and that can last for days. It can be associated with imbalance and sometimes even vomiting.

And then they just come out of it and they're fine for months at a time. So that's an interesting one as well. Again, we suspect that that has something to do with some precursory issues to migraine or maybe even a migraine variant.

And finally, we'll see kiddos with seizure disorders, panic attacks or any other type of neurological deficit.

Chart review

So we did do a chart review of our kids that we've seen over the past five years. And what was interesting is a little less than a third of them were diagnosed with peripheral etiologies, where we could see that on the test, that they actually had peripheral issues.

So these are all the kids who have come into our clinic over the years, who have come in with either vertigo or balance disorders. And they were, a third of them were peripheral.

Now I'll just tell you this spoiler alert is another third of them were central, like we actually found central findings on our exam. And the other third of them had normal exams. And of those normal kids, some of them still ended up being diagnosed peripheral down the line, or central down the line.

And some of them got sent to psychology or you know, other entities as well, even Ehlers Danlos clinics, cardiology, those types of things as well.

But these are the kids, I want to show you guys that we've seen that have been diagnosed with peripheral etiology. And of those kids, all-- a little over half of them also had hearing loss. So, hearing loss-- to say that hearing loss and vestibular loss go together is a true statement.

But I wanted to break it down even further for you. Because a lot of you around the world might only see kids once in a while. And you might be thinking to yourself, "What is the one thing I can do to figure out if this child who's coming into my clinic has a vestibular problem?".

And we get this all the time from our own physical therapists too. So I did a search for who had no hearing loss, they were under 10 years old, and were diagnosed peripheral. So they had a peripheral etiology. And of that only 15 kids showed up. So the good news is, the number one thing you can do if a little tiny child comes in with vertigo, the number one thing you can do is do a hearing test. Because that'll screen out most of these kids for you.

Now of those kids, only two of those kids had bilateral weaknesses of unknown etiology. And so we've hypothesized on those kiddos over the years, maybe they had a unknown, undetected congenital CMV, and all their other systems were fine.

So there, it's hard to know exactly why those two kids have bilateral weaknesses, but more to come, they're definitely very interesting cases.

Goals and expectations of vestibular testing

So when I'm testing a kiddo, I want to think about like what my goals and expectations are of testing.

From birth to two years of age

And so from birth to two, we're going to try to get a physical therapy rehab, do a cVEMP, get some rotary chair, and do head impulse testing.

From two to three years of age

From two to three years old, now we're starting to add oVEMP, especially when they're closer to three. And we can also add some subjective bedside testing. And maybe we can even get the vHIT goggles on them.

From three to four years of age

From three to four, now we're adding headshake from the VNG, some positional testing.

Five years of age and up

And from five and up, we can really start to think about adding caloric testing.

Case study

So this is our official case. And it's a four-year-old who walked at age two, they are always falling and always clumsy, and they have to hold on to put on their pants or go up the stairs. She's always been clumsy. When she goes up the steps, she kind of holds on to the wall or the handrail.

And she-- her mom says that when she transitions from surfaces, she falls. And mom also is noting dizzy spells. And these dizzy spells can last hours. And we don't know what the cause of her hearing loss is. But she does have a hearing loss. It's a moderate, it's a severe rising to moderate sensorineural hearing loss in the left ear only. So the right ear is totally normal.

So already we're starting to think, okay, asymmetric inputs. This would be things like torticollis, which she doesn't have, that's good. But asymmetrical inputs could also mean vertigo, too, especially if they flare up. So whenever I think about testing a young child, especially below seven years old, I want to keep it simple.

One is, I'm going to be thinking of the site of lesion. So I'll be thinking of: is it central or peripheral? I really want to help the physical therapists by giving them this piece of information. The second piece is: the side of lesion. So is it a partial functioning system? Or is it a total wipeout? Is there no function at all?

So if it's a total wipeout, and there's no function, we would be using things like substitution exercises in vestibular rehab. So we want to know is there anything to rehab at all?

So because she's four, we're going to be using this model for our expectations of testing. Every child is different. So there's no clear-cut way to tell you this is what we get on every single child, but this is what we strive to get on all the children.

1. Physical therapy evaluation

So for her, we started with physical therapy. And so she did a vision screening and she said she had normal head impulses and normal head tracking. She did a muscle screening and she said she had normal tone, endurance, strength and range of motion. She did gait testing and she was able to maintain a straight path 60% of the time.

She does notice that she runs on her toes, and she ascends stairs alternating feet, which is step, step, step, step... that's appropriate. But she's holding a rail. But when she descends stairs, she uses a marking pattern. That means she steps down and then joins the step...steps down, joins the step. That's a little bit abnormal.

And then finally, with balance, she was able to complete 20 seconds with eyes open and eyes closed on a firm surface. That's great. But on foam, she fell with her eyes closed.

So I'm going to show you what that looks like. I'm gonna have you stand. Right. I'm just gonna see how you can see a real still for me like a statue. Good job. Simon says: put your arms across your chest like this. You can do it with your toys too. Good job, good job. Here we go. I'll jump ahead here.

So in reward for following the directions appropriately. We gave her bubbles and surprises and stickers. She's holding some in her hands. And this is what it looks like with her eyes open on foam. Ready? Oh, you can look at your sticker. She's very motivated by that. So then we wanted to check her with her eyes closed and children are notorious cheaters...they always open their eyes, and they never keep their eyes shut for the entire time because it's boring.

And they're like hey, "still out there?" So we came up with a plan for this little girl. Cross your arms Right, ready? Oh cute. Why don't you grab the mask? Her face mask over her eyes. Dual purpose. Alright, this is gonna be silly. That we have built in blindfolds now. Okay ready? And that was very difficult for her as you can tell when we took away the proprioception- the firm surface- and we also took away her vision she was unable to stand.

2. VEMP

And the next thing we want to do with the vestibular spinal reflex pathway is look at her cVEMP. So this is how we tested her cVEMPs: she sat on mom the whole time, nice and comfy. And we also had a cartoon playing this time. My colleague Kay Bachman was using the computer and looking at contraction so she would let me know.

The nice thing is we actually used the rotary chair for this and so when we put them in the rotary chair we can actually turn mom's chair so that she actually has to turn her head to watch TV. The TV doesn't move but the rotary chair we used as her... so she could see the TV.

Okay, so what ends up happening is this little peak over here they did not match up exactly, so she did not have any response. On the other side, she has a huge response. I'll show you that in a moment. We also set them up for oVEMP and this is our traditional setup for cVEMP and oVEMP... all the stickers are on them here, but we usually try to now take the stickers off of the cVEMP area and put them on if they don't hurt when they come off.

So I'll show you what that looks like. I think actually got a new pair for her. So she's watching an iPhone and she does not care what I do. So the great thing about having little devices or a TV in the room is that you can distract the kiddos, you can play games with them, you can show them toys, she doesn't... her mom said she doesn't watch a lot of TV at home.

So the nice thing was, is we can use that to our advantage and let her watch a TV while I get her electrodes set up. So I'll jump ahead here. I also put the TV up so I can see where her eyes are. I go right below midnight and slightly lateral to the outside here to place my oVEMP electrodes to get the belly tendon.

And she's just looking up watching her show, she does not even care. Now this is the awkward one, it goes on the nose. So we try to reduce the amount of time that this is on their faces, I do let them know I'm going to touch it, see, I'm going to put my finger there. So she knows I'm going to put it right there.

I tried to keep the wire out of her face as much as possible, so she's not looking at the wire. Okay, and when we test it, we just hold the device up so that it deflects her eyes upwards. So we're able to get a really good picture of the inferior oblique. Helps to have an extra set of hands to help you.

And she is a real patient, she's not a model, she just did a great job for us. And you know, really, let us do whatever we want. It doesn't always work out so perfect. But as you can see the oVEMP jumps right up, you get a negative peak right away. And this is what it looks like in the end.

Oh, I'm so sorry. That is so funny. I caught a mistake on here: that is marked backwards on the right-hand side of your plane, you would actually mark the N1, now I'm just noticing those for the first time, oh gosh! The N1 will be marked first and then P1 is the second peak. On the left-hand side, it is P1 first and N1 second for the cVEMP. So, flatline for the left ear on both sides. So no cVEMP and no oVEMP.

3. Rotary chair

All right, so we can also for rotary chair now, we can test in multiple ways. And this is what we love about our rotary chair so much. So one is we can do a horizontal recording with electrodes. We can actually do electrodes here, here and here. So this is where we would put one for the horizontal and we're using all the left channel.

So instead of using the inner canthus here for the left, we're just going to move it over to the right side. And then of course, we need the ground. So barely any electrodes at all, especially if the teeny tiny electrodes, this is helpful. They can ride in a car seat, they can ride on mom's lap, but we are able to record some of the vestibulo-ocular reflex.

As in traditional ENG, electrodes do have very noisy recordings. And they are offended by things like people moving, touching wires, blinking a lot those types of things. So just so you know, the cleanest recording comes from the goggles. So we try to get the goggles on as many kids as we possibly can.

In this case, this was all set up as the left recording, and we use jumper cables to close off the vertical channel in the right channel as well. Sometimes we are happy to get... sometimes kids won't let you touch them at all.

And so another option for rotary chair is we have an in-room camera. The in-room camera is nice because you can actually get data on their eyes, but it's qualitative. So you're able to tell: does the I move to the right? Does the eye move to the left? And here's what it looks like. And that's some good movement in directions. So that way we know this child does not have a bilateral weakness; there is movement in both directions.

And then the next level up for rotary chair is sometimes the kids will only wear the goggles for a short

period of time. What I have found is that with two-year-olds, the magic is limits. They don't want to be sitting on their mom's lap for an endless amount of time, with nothing to be rewarded for or nothing to get excited about. So we tried to combine the fact that we're going to set a limit, a time limit for them.

And then we're also going to set a limit for how long it's on their eyes and then also there's a reward. So after you do all this work for us, there's going to be reward at the end.

So this little guy, he's a two-year-old. He didn't want to wear the goggles because the straps are tight, and it pushes on their faces. But instead he was okay with me holding it up for him. We do this a lot for two-year-olds, and I'll walk with him in the rotary chair.

And then in addition afterwards the reward is he used to play with my light-up toy which made him very happy to go in the booth, turn out all the lights on the rotary chair and then play with the light-up toys. So let's see what that looks like.

So he knew if I did it, I'm gonna get to play with the light for a few minutes or blow bubbles or whatever it was. So sometimes it's a bunch of stickers on my shirt. But I always tell them like, first we do our work, and then we get our surprise. Or we're only going to put this on and we're going to sing happy birthday. And that's it.

So we just let them know like, it's just a period of time. We're gonna sing Itsy Bitsy Spider, and then all done. Or in this case, Happy and You Know It, and then all done. So that really helps with the kids. They're very logical beings. And they just want to know like, you're not going to leave me here like this are you.

Now of course, in our case, back to her, she was a perfect angel, of course and wear the goggles with the straps. One hack I did on the rotary chair you can see is I put some Velcro strips on the back of the chair so I could put in my head brace. Sometimes the kids don't reach to the top. And also with the pediatric goggles, there's no Velcro on the back.

So I just put some stickable Velcro and then I can throw the piece away, the other piece, the soft piece that touches her in between patients, I just buy long roll of it, I can throw it away. And then I also changed my goggles to Velcro too.

So the other thing is the kids with the strap on the goggles, sometimes they don't like the rubber strap that pulls their hair. And then when I adjust it, it bothers them. This is quick release on and off, I put two pieces of Velcro on the sides of the goggles. And again, I can take this piece that touches the hair and throw it away between patients.

So let me show you what this looks like. Of course, she was a champ, like I said, you can see her eye on the screen. So we have this rotary chair, the open rotary chair, and we also have the closed rotary chair to you see both.

And so what you see in the background is my colleague, Kate Bachman is showing her the fixation light. So sometimes with kids, they look around or their eyes get caught in a corner. If we flash the fixation light, it brings their eyes back to rest. Hopefully, that's uh, I know, that's a ton of hacks.

And if you need to watch this back, feel free to rewind, that was a lot. So with rotary chair, the reason why we love it so much is that we consider it to be an overall picture of VOR function. Obviously, if you're a bilateral kid, you're not going to have any eye movement at all.

But the nice thing is, is it tells us about compensation. So imagine you're testing a hearing test in your sound booth, and you're doing VRA in sound field, the nice thing is, is if the child has a totally out ear, like they have no hearing on one side, chances are they might still pass your VRA testing, right, because it's a measure of compensation.

So again, if you have one good ear, you can compensate pretty well and still pass that part of the test. Doesn't tell you about ear specific, but it does tell you about overall compensation. That's how I view rotary chair. Rotary chair is our measure of compensation. And if they're compensated for their one ear that's down, chances are they're gonna have a beautiful rotary chair evaluation.

And that's a good sign, that's really, really helpful in the process of compensation. And you don't have to do every frequency to get a perfect test. So for example, in gain, you heard in the previous talk, that gain is a measure of like the robustness of the nystagmus. So how much nystagmus you have is related to how much movement of the chair that you have.

So in this case, anything between the two bars at the top and bottom. So this is normal, these points are between them, nice and normal at the low frequency and at the high frequency. So that tells us that at lows and high frequencies, she's pretty compensated, she has good VOR movement, even if one ear is totally out, she still has some really good movement of her eyes, that is compensated pretty well.

Then we look at phase which is the timing of the reflex. This is our next level of compensation. So how well does the timing of your VOR work? And in her case, she's also normal for low and high frequencies which is great to see.

And then, here's the best part, is that for symmetry, this tells us how much eye movement she has to the right and how much eye movement she has to the left and are they equal. Her brain has compensated also, which is so great. So even though those cVEMPs and oVEMPs are out, for her VOR in an overall picture of compensation, she looks amazing.

So this is why we love rotary chair because it gives us so much information for what is going well, as well as sometimes when things are not going well.

4. vHIT

Another measure of VOR is our vHIT testing. And so because the vHIT companies use a perfect circle in their algorithm to determine if the pupil is on the screen or not...sometimes the pupils are very large in children and that is supported in the ophthalmologic data as well.

Your pupil continues to grow up to age 15 and then starts to drop off and look more adult like. So a 40-year old's pupil size is much different than a 14-year old's pupil size. Okay? So because the pupils are so big, sometimes the eyelid obscures part of the pupil, and then you don't have a perfect circle anymore.

So sometimes the vHIT doesn't pick that up. So because of that it is sometimes harder to get some of the vertical canals. But we have really good success with the lateral canals. I feel like that data must be echoed even in the touchless vHIT systems in Europe, because I've seen you know for the little ones, a lot of times they do try to get lateral canals as well. I'd be interested to know.

So some of the hacks that I have for vHIT are: reduce the pupil size. And so I'll use an actual like touch puck light next to their eyes. I'll show you what that looks like.

All right, so a lot was going on in that video. One: I have the puck light and I'm holding it near her eye here just to reduce the pupil size. Another idea we have is she can watch a video across from her. That's what Sabrina is holding up for us.

There's also bubbles so if she needs a little reminder to come back to center, we can like blow a bubble or two to have her watch that. We just need something to hold her attention. So bubbles are not the best because the bubbles float and fall. But she just gets excited about bubbles, so we can even take little breaks and blow bubbles in between.

But she is watching the cartoon. So that keeps her eyes forward, and we can do the quick motions. In addition, she's sitting on mom's lap, so we were able to get her to sit on mom's lap, while she didn't want to sit alone, she was nervous. But our tester reaches around mom and then does the little head impulses there.

So we were not able to get any data on the LARP position. But we were able to get data on some of the other canals and she doesn't have any big repeatable saccades anywhere. I know, there's some low gain on the right anterior, and when we did our own norm study, sometimes we did find lower gain in the vertical canals. But nonetheless, there was no significant saccades in any of the planes noted. So that looks good.

So that kind of supports our rotary chair results, which is showing the VOR is looking pretty good.

Conclusions on case study

So the conclusions for this case. Site of lesion, we are looking at central versus peripheral and for her, we're also looking at side of lesion.

So for site of lesion, we're looking at more peripheral. Again, she didn't have cVEMP or oVEMP. She also fell on the foam. And for side of lesion, she's a partial function, so she does have good function. Her right ear is completely intact, and she is compensated very well in terms of VOR which is great to see.

She does still need some improvement on balance, as we noted with her having the marking pattern coming down the stairs, and also falling on the foam with her eyes closed. And then finally as well we also saw the cVEMP, which is vestibular spinal reflex is out so that kind of confirms all that.

So for her, I'm just going to finish that up, so for her we're going to add some vestibular rehab therapy for her to just get her up to speed on those issues that she's having.

Update on a previous case study

So to conclude for everyone, I'm going back to my cheerleader, because if you saw my case last year, you know I presented on a little girl who had a bilateral vestibular weakness after receiving two cochlear implants and she was having some issues with that.

But she has had a year of cheer, so her mom put her in cheerleading, and she is doing amazing. This is her standing on one foot like a pro and has her leg way up in the air for that heel stretch. And then here she is cheering for us.

Beautiful cartwheel. But if you're wondering if she still has a bilateral weakness... indeed she does. She cannot stand on one foot with her eyes closed. So cute. So the bilateral weakness is still there but with all of her rehab and her cheering she is doing a great job, and she is functioning very normally in the real world which is great to see.

So that means she can probably put on her pants by herself now, especially when she has her vision, and she can get in and out of the tub which is a safety concern. So she's doing great so all good to see.

I hope that you enjoyed my case and, my cases, I should say, that I shared with you today.