Andrew Wilner (Host): This is Better Edge, a Northwestern Medicine podcast for physicians. I'm your host, Dr. Andrew Wilner, Associate Professor of Neurology at the University of Tennessee Health Science Center and Division Director of Neurology at Regional One Health in Memphis, Tennessee.

Today, two experts from Northwestern Medicine, neuro-otologist, Dr. Nicholas Hac, and neuro-ophthalmologist, Dr. Neena Cherayil are going to tell us what they learned by looking at the eyes of our patients with dizziness. Welcome, Drs. Hak and Cherayil.

Dr. Nicholas Hac: Thank

Dr. Neena Cherayil: Thank you for having me.

Andrew Wilner (Host): Okay. Well, to get started, Dr. Hac, tell us a little bit about the kinds of patients you see. Who gets referred to you and what kind of test you do?

Dr. Nicholas Hac: Yeah, great question. Most of what I see is just patients who have the chief complaint of dizziness or vertigo, anything along those lines. So, it's just one or two chief complaints type of clinic that I end up seeing patients, sometimes also patients with some abnormal eye movements. What I do a lot is a pretty extensive history on these patients to get a lot of information about what types of things trigger their dizziness, how long does it last, what are the associated symptoms and how do they actually themselves describe the symptoms that they have. And then, there's some extra special testing that we do. It depends a little bit on what history I gather from the patients. But beyond the general neurological exam, I have a very close look at patient's eye movements in various circumstances. And then, we use the video goggles, so the Frenzel goggles to put on patient's eyes to take a very close look at their eye movements. And then, sometimes some extra vestibular testing, such as the video head impulse test, or I rely on some of my audiology colleagues to do things like caloric testing or VEMP testing, et cetera.

Andrew Wilner (Host): Okay. Now, Dr. Cherayil, I heard eye movements mentioned a few times. Is that where you come in?

Dr. Neena Cherayil: Yeah. So, Dr. Hac and I work closely together. I'm a neuro-ophthalmologist. I treat the visual manifestations of neurologic disease, so that could be anywhere in the central or peripheral nervous system. And there's a subset of patients with dizziness or vertigo who have vision problems that are contributing to their primary complaint of dizziness. So, this could include things like ocular misalignment or double vision that could be affecting their depth perception or giving them a little bit of uneasiness in certain directions of gaze. Abnormal eye movements such as rhythmic eye movements like nystagmus can cause the symptom of oscillopsia, which is the jumping of your visual environment. And vision loss as well can contribute to dizziness as a symptom. So, both of us can work together to address the different facets of dizziness that way.

Andrew Wilner (Host): Okay. So, how about an example? Can you give me an example of a patient that you saw recently whose eyes were wiggling around and you were able to figure out what it was and then you were able to make them better. Does that ever happen?

Dr. Neena Cherayil: I can go ahead with an example that we have a Large Movement Disorders Division at Northwestern and we get referred lots of patients who have degenerative cerebellar conditions that can cause nystagmus or that symptom of oscillopsia. Recently saw a patient with downbeat nystagmus, started a medication called dalfampridine and the patient actually had significant improvement in that symptom of oscillopsia and really improved their kind of gait dysfunction and a little bit of the dizziness feeling that they were having as well in the setting of their underlying neurodegenerative disease.

There are lots of other treatments too for double vision in particular. So, sometimes a patient may describe dizziness as kind of a vague symptom, but it's very gaze-evoked. It's only when I'm going down the stairs or when I'm trying to look down to read. And a lot of those patients may actually have congenital nerve palsy, such as a fourth nerve palsy that's causing subtle double vision that they're not interpreting as such. Those patients are easily treatable with prism therapy or by one of our strabismus surgeon colleagues with a eye muscle surgery.

Andrew Wilner (Host): All right. Let's get back, I want some practical advice for physicians. Is there an easy way to look at the eyes for a non neuro-ophthalmologist and see abnormal eye movements and say, "Ooh. These abnormal eye movements are bad. You better go see the neuro-ophthalmologist" or "Well, these abnormal eye movements are okay"? Is there some way to differentiate benign from malignant or do all of these patients need a comprehensive evaluation?

Dr. Nicholas Hac: So, I can start with that one. I think the example that Dr. Cherayil had brought up of these patients with a downbeat nystagmus, that does tend to be a bit of a red flag that there is something going on in the brain, probably the cerebellum. It depends a little bit on the time course of the symptoms is what I would say. So if this has probably been going on for a long time, slowly worsening symptoms over the course of months, it's not like there is some urgency to send this person to the emergency department now. But it is the type of person that you want to make sure that you get advanced neuroimaging on these patients as well as try to do a pretty thorough neurological exam looking for ataxia and brainstem signs on patients like this.

I think probably as my rule of thumb, if you have somebody who has a spontaneous vertical nystagmus, whether it's upbeat or downbeat, or if they have a spontaneous torsional, so that means if you're looking at the eyes and you sort of see that they're just spontaneously twisting, that all of that is a red flag that there is something wrong going on in the brainstem or the cerebellum. And so, it requires further evaluation.

Andrew Wilner (Host): Would most of these patients get, say, an MRI of their brain as part of the workup?

Dr. Nicholas Hac: Yeah, that would be my recommendation because you always want to look for the possibility that there could be some sort of lesion, whether that is a demyelinating lesion, a slow-growing tumor, et cetera, that could be causing those symptoms.

Andrew Wilner (Host): Okay. You know, I'm a neurologist and I see a lot of dizzy patients. And frankly, it's often challenging to pin it down. Of course, we do do a thorough history and neurologic exam, look for focal findings, any associated findings, do an MRI, but often come up empty handed, I would say more often than not. At that point, I say, "Well, I don't know. Maybe it's inner ear," something like that, the labyrinth. Is that a reasonable thing to say?

Dr. Nicholas Hac: So, I can also answer that question too because I think about inner ear stuff as a neuro-otologist or an otoneurologist, depending on who you ask. It is certainly a reasonable consideration. The brain is still a possibility. I think that the big two diagnoses are BPPV or benign paroxysmal positional vertigo, where sometimes even when you do a Dix-Hallpike, you just don't see any eye movements. But if you have a highly suggestive history, it's reasonable to assume that, send the patient to vestibular physical therapy. Maybe with physical therapy, they examine the patient a couple more times. And then suddenly, the eye movements that are classically associated with BPPV show up, it's just that it could have been in remission at the time that you see the patient.

But the other big diagnosis that I would encourage everyone to think about would be vestibular migraines, which is just a very common thing that I see in these patients. They do not have to have headaches at the time that they're having dizziness. It's very common for them to have a history of headaches that sound consistent with migraines. But with their episodes of dizziness, they may just have some associated sensitivity to light, sensitivity to sound, maybe some nausea that sound a little bit migrainey. And they might have some classic migraine triggers such as stress-induced, certain foods that can induce the symptoms, caffeine, alcohol or just not having had anything to eat. And so if you get a history like that, where you're noticing some migraine triggers here and there, you're noticing some associated migraine symptoms, then at least think about vestibular migraine as a possibility.

Andrew Wilner (Host): Oh, that's interesting. And Dr. Cherayil, I suspect that migraine is in your differential diagnosis as well.

Dr. Neena Cherayil: Yeah, We see a lot of patients with visual disturbances associated with migraine. They can have kind of mixed positive and negative phenomena, so, you know, the jagged wavy lines and colorful lines, fortification spectra or the glimmering, missing spot in their vision. It can be really alarming to patients when they don't have a name to it or an explanation for it. We certainly want to make sure that we're not missing any ocular causes of visual symptoms, especially if it's just pure vision loss, which would be unusual for a migraine aura. That's certainly a diagnosis that's seen very frequently by neuro-ophthalmologists.

Andrew Wilner (Host): Well, since there are so many of these patients with difficult to diagnose symptoms of dizziness and difficult to treat, I think symptoms of dizziness, what do you do at Northwestern that's special to help these patients?

Dr. Nicholas Hac: I guess I can get started on that too. I think some of it really It's helpful to just see someone who sees these patients all day, every day for one thing. At the end of the day, you do get a little bit of a gestalt, I would say, when you see these patients for what could be going on. But that specialized testing is really important, like when I put those Frenzel goggles on patients, in particular for the BPPV patients, and so bring their heads back, do various positional maneuvers. It's just much easier to see subtle nystagmus patterns that otherwise I think when you don't have that sort of equipment, you try to put the patient in the Dix-Hallpike position or a supine roll position and you can't see any nystagmus. It really helps in actually solidifying the diagnosis by seeing that classic eye movement pattern. You can also with some of this testing test for some of these inner ear causes, as you said, Dr. Wilner, to actually also prove that it could very well be an inner ear cause that's causing these symptoms. So, a little this, a little that.

And of course, some of these patients are very complex. And so, I rely on some of my other colleagues. You know, a lot of migraine patients, they have these associated visual symptoms. And so, always in the back of my mind I'm wondering, "Should we be doing a little bit more of a thorough look at these patients?" And so, I asked Dr. Cherayil to see those types of patients, and it may be that there's multiple things going on. It's not always Occam's razor when it comes to these patients where everything can be explained by one thing. Sometimes, a patient can have as many diseases as he or she pleases.

Dr. Neena Cherayil: I'd like to add that I totally agree with Dr. Hac, the optimal management of a lot of patients, especially patients with dizziness requires getting to the right diagnosis to target the right treatment. And sometimes that requires specialized testing and evaluations with subspecialists.

Andrew Wilner (Host): I wanted to ask one more thing. Dr. Hac mentioned earlier physical therapy. So, it sounds like you have a comprehensive program where there's a diagnosis and, of course, we recommend treatment and physical therapy when needed. What do physical therapists do with dizzy patients?

Dr. Nicholas Hac: Yeah. So, that's a great question and it somewhat depends on the diagnosis. I think that vestibular physical therapists are excellent at treating BPPV in all of its forms. So when you have the otoconia running loose in the inner ear, it can go into a variety of places. The classic example is the posterior canal, where people get seconds to minutes of dizziness when they tilt their head up or down, or when they sit up or lay down, or when they roll over in bed. And so, physical therapists are really good at using the canalith repositioning maneuvers to move the crystals back into the utricle where they came from.

But the other big disease categories are in unilateral vestibular weakness, which has a variety of different diagnoses. So, the classic example there is that somebody who has an acute onset vestibular neuritis. Physical therapy is incredibly helpful for treating these patients. They can do these gaze stabilization exercises where they have them practice using their vestibular system over and over and over again, so that the brain can adapt and can learn how to live with that new deficit from a vestibular neuritis.

But it's not just vestibular neuritis, it's also tumors, vestibular schwannomas, that type of thing that impinge on the nerve and can lead to some vestibular weakness as well that they can be very helpful with. And those are the two big categories in which physical therapy has been proven in many studies to be helpful. But also in my experience in patients who have things like vestibular migraine, their dizziness is often triggered by very complex sensory environments. So, they classically describe going to a grocery store or department store, and there's so much activity going on that they get dizzy. And so, learning how to cope with these environments can also be helpful. And so, many vestibular physical therapists who are familiar with that diagnosis can help them learn to adapt and habituate to these more complex environments.

So, there's a lot of ways in which I work with physical therapy to help these patients, and oftentimes at Northwestern, we have many of those physical therapists throughout all of Chicagoland and I frequently message with them so that we can co-treat and help these patients.

Andrew Wilner (Host): Well, that's terrific. That wraps up our discussion on the neuro-otologic and neuro-ophthalmologic approaches to dizziness with Drs. Hac and Cherayil. Thank you both for joining us.

Dr. Neena Cherayil: Thank you.

Dr. Nicholas Hac: Thank you.

Andrew Wilner (Host): To refer your patient or for more information, head on over to our website at breakthroughsforphysicians.nm.org/neuro to get connected with one of our providers. And that concludes this episode of Better Edge, a Northwestern Medicine Podcast for physicians. I'm your host, Dr. Andrew Wilner. Thanks for listening.