Vestibular Rehab Blog Series: 4 of 12
Welcome back. We're finally at video three of lesson two, and this is where we take the information we've gathered from the intake, created a working diagnosis, and now be thinking about the clinical tests that we want to do. So when we talked about BPPV, if vertigo was brief in nature and related to position changes, then we want to first, start with vertebral basilar artery insufficiency screen or BVI screen and then do the Dix Hallpike and/or roll test. And remember, BPPV is due to those loose otoconia or ear crystals floating around in one or more of the canals. You have three semicircular canals on each side.
Remember, BPPV is the most common cause of positional vertigo. And fortunately, the majority of the time it is the easiest to treat. Successful treatment occurs greater than ninety five percent of the time and in one to two visits. So here's the Dix Hallpike. The person starts in sitting. Let's say you suspect the right ear. You have them turn their head to the right. You want to support their neck and you lie them back with a little bit of extension and you're going to observe the eyes for nystagmus. Now, for those of you that are watching that are either interested or signed up for our more advanced vestibular course, we'll be talking about BPPV in much more detail and not just classical BPPV, but a typical BPPV. And so the Dix Hallpike is testing for BPPV in the posterior canal where the ear crystals are floating around, but also for the anterior canal, which is rare.
The role test is looking at the horizontal canals. You can start them supine, the heads in flexion, and then you turn the head to the right and you're observing for what we call horizontal nystagmus. Is it geotropic or ageotropic? You have to turn the head to both sides to know if it's BPPV. And again, this is looking for the ear crystals associated with the horizontal canal. Each of those canals innervates a different eye muscle, which is why we get different nystagmus depending on the canal that is being affected. So, we started this video by talking about BPPV and then we moved on to Meniere's and MAV. So again, this is dizziness lasting for 20 minutes to a couple of hours. May take one to three days to recover. You want to be considering a fluid problem, especially if there's otologic symptoms such as fullness, hearing loss, or tinnitus. So, here's where we're thinking about the Meniere's disease or potentially vestibular migraines.
So, the clinical exam at a minimum should be a neuro screen, which is oculomotor, coordination, tone, etc. Screen for hearing loss. There's Romberg on a firm or foam, a head thrust test, and a DVA. I won't be demonstrating these tests. We'll be going over that in detail in our more advanced course. And remember, a key indicator is you want to refer for a comprehensive audiogram in consideration of a test called an ECoG, which tests the fluid of the inner ear.
What if dizziness is lasting hours to days? We talked about considering an inner ear infection. Labyrinthitis would be with sensory neural hearing loss and a neuritis without. Look how familiar this is: a neuro screen, a hearing loss screen, testing Romberg on foam and firm for inner ear, the VOR, the DVA. Ideally, we would like to be also doing some type of gait test, such as a dynamic gait index, the 4-item DGI, which is a shortened quicker version to do. In those patients that aren’t as higher functioning, we want to consider gait tests such as the timed up and go (TUG) or the Tinetti.
And here on the picture to the left, it came out a little blurry. But remember, you know, dehiscence is a structural abnormality. So, it's called superior canal, which actually is another name for the anterior canal. There's typically a protective layer there to prevent it from bumping up against a hard, bony surface. But that layer can be thin and it can actually be gone. And then it causes a disruption of what we call actually a hole in the superior or anterior canal.
The clinical exam: It's the same of what I just talked about. But again, a comprehensive hearing test is super important. If there is what we call a low frequency air bone gap, then we recommend a VEMP, which is a specialized vestibular diagnostic test and if that's abnormal on the same side or on both sides, then a high resolution CT scan is recommended to confirm the diagnosis of superior canal dehiscence. We talked about dizziness with pressure, Hennebert’s Sign, that's more related to a perilymphatic fistula. This is different. This is an opening between the air and fluid filled space. So, a little bit different than superior canal dehiscence, and that's why the symptoms are slightly different. The exam, though, the same. One of the things with the suspected perilymphatic fistula, and certainly you could do this with superior canal dehiscence, is perform a Romberg with closed glottis valsalva and a Romberg, remember, is feet together, eyes closed and a closed glottis Valsalva is when you have them bear down and hold their breath ideally for 20 seconds. So during the closed glottis Valsalva, you would observe for increased symptoms and/or postural sway. Ideally you would have video goggles or frenzel lenses that they would have on because this can also elicit nystagmus.
With perilymphatic fistula, if they have hearing loss, it's a different type of hearing loss than with superior canal dehiscence, and so I think you're going hear from me, no pun intended, that comprehensive hearing tests are super beneficial.
So, we also mentioned an acoustic neuroma. This is dizziness and unsteadiness with report of hearing loss in one ear. We really always need to be thinking about a comprehensive hearing test right away because we want to rule out more serious pathology. It starts out as a benign tumor typically on the hearing nerve and then it starts to grow and can actually begin to cause dizziness because now it's hitting the vestibular nerve. And in more severe cases, it will actually begin to cause facial paralysis and even affect the trigeminal nerve if it's large enough. If this tumor becomes large enough, it actually can press against the brainstem and/or the cerebellum, even resulting in central signs.
The clinical exam, same as the previous. Now, when you do a head thrust, you might get a positive head thrust to the affected side and we would typically expect abnormal dynamic visual acuity testing. Romberg on a foam would likely be difficult. Once again, referring for comprehensive audio, if that audio shows a high frequency sensory neural hearing loss then an ABR is recommended and then an MRI. Now I know that the medical system is set up a little bit differently than the way I'm addressing it here. Oftentimes patients have already had an MRI and then they're coming to see you.
We also talked about neurological disorders. Now, I specifically referenced double vision, dysarthria, changes in coordination and this is because I'm thinking more about the cerebellum and/or the brainstem being affected. Certainly, another red flag if they report headaches that are worse at night. And I even consider, falls without an explanation. Is there something central going on? However, falls without any explanation can be associated with anxiety as well. So, if they're presenting with these symptoms, we want to consider a neurological component. The test is the same, but you do want to think about a more comprehensive cranial nerve exam because the majority of the cranial nerves run through the brainstem. And so with neurological disorders, you may see multiple cranial nerve involvement. But during the ocular motor, when you're having them follow your finger, they would be making these really quick corrective saccades during smooth pursuit or when they're looking target to target, they may be under or overshooting with saccades. You also want to perform upper extremity, lower extremity coordination testing. Like the guy on the left, it looks like he's about to perform rapid supination pronation.
If the primary symptom is more movement related dizziness, still consider the inner ear because of that keyword ‘movement’. But it may not follow more commonly known disorders that we've discussed. The key characteristic ‘movement related’. The clinical exam is the same as previous recommendations. If the patient's functioning at a higher level, then the abnormal test would most likely be in the dynamic visual acuity test or the dynamic gait index. There's also a more advanced version of the dynamic gait index, which is the functional gait assessment. So even standard vestibular diagnostics may even be normal, such as a VNG. If the patient is older, it could be age related factor or multifactorial.
And I want to talk about ototoxicity. Again, this is an unsteadiness that I mentioned that begins after receiving IV antibiotics or cancer treating drugs and the antibiotics are particularly amino aminoglycosides. And here I have a Romberg. You can certainly do a Romberg on foam, but with ototoxicity, just a Romberg on a firm surface can be difficult. You definitely want to do a head thrust test. And with that you would suspect a positive head thrust, which is rare. If you see a positive head thrust, you know, bilateral vestibular loss isn’t common. Again, you want to recommend a comprehensive audio, VNG with calorics. If they have bilateral loss with the calorics with the air or water in the ear, there may be no response. And utilizing ice calorics would be the option. Computerized VOR testing that can be done with the rotary chair or fast VOR testing with a VHIT and then VEMPs. So vestibular diagnostic testing is important with suspected ototoxicity. The clinical exam is the same, but really you need to be cautious with balance test. Again, they’ll likely not be able to perform the eyes closed on a foam, a head thrust would be positive bilaterally and with the DVA there may be a five line difference and reports of what we call oscillopsia or the letters will jump around.
So, I'm going to show you two very short videos. This is a head thrust test. It's a very quick movement to the side. If you turn their head to the left, you're testing the left cranial nerve or eighth cranial nerve. And if you turn their head to the right, you're testing the right side. So, look very closely and see if you can see what we call the retinal slippage, where her eyes slip off my nose when I move her head quickly. It's very subtle. There it is. You see that little jump? She's making a corrective saccades and there it is again. It's so slight. Now, when you're the tester doing it, it's more obvious. And this video just demonstrates the DVA. So, they're looking at it. They read the eye chart with the head still. And now you're moving their head. She did report oscillopsia and had greater than five line difference between static and dynamic vision. And this occurred after given antibiotics.
So, let's talk about some of the other disorders. We mentioned MdDS and PPPD. You want to still perform the same clinical tests that we've been talking about. All your tests may be normal. You could consider a hearing test and even vestibular diagnostics for more objective testing of the inner ear. But that typically comes back normal. You still recommend vestibular therapy. Vestibular therapy has been found to be beneficial in both of these conditions.
So vestibular diagnostics, we will be talking about that in a follow up lesson. But I want to briefly mention how useful they can be. Oculomotor testing provides a high level of sensitivity and specificity to central nervous system disorders. And obviously positional testing can help reveal peripheral vestibular, central, and/or even cervicogenic components. Comprehensive hearing test can provide a lot of insight to structural abnormalities of the inner ear, fluid fluctuations of the inner ear, and can help be a differential in migraine associated vertigo. Some of the challenges we see with vestibular diagnostic testing is they're done as a kind of gold standard for the inner ear. And people don't look at the value of the oculomotor or even types of nystagmus that may indicate central. We see this a lot with head trauma and/or cervicogenic involvement.
The other difficulty is just that symptoms are often so similar between these, particularly with vestibular, the visual system, and the neck, you can't really separate those three systems. When someone comes in, their symptoms can be coming from one or more of those systems. The reliability of vestibular diagnostics varies greatly. It relies heavily on proper technique and a thorough evaluation. Ideally, VNGs would be performed by a specialist. They're not as readily available. We've been providing vestibular diagnostics in the clinic since about 1996 and it was much more common in ENT practices at that time, but we've really seen that number go down. A lot of that has to do with insurance reimbursements or lack of.
So, could there be more than one diagnosis? What are your thoughts around this? So, we've talked about BPPV, inner ear infection, Meniere's, migraines, MdDS, 3PD, general vestibular dysfunction. Well, the answer is yes, yes, and yes. And there's a reason there's a unicorn on this slide. Need to stay tuned. We're going to come back to the unicorn. So BPPV has a high occurrence with inner ear infections, Meniere's disease, and migraines associated vertigo. Some patients have Meniere’s, migraine associated vertigo, and 3PD and BPPV. Patients post head trauma can have the sudden onset of vertigo just like an inner ear infection. This is called a labyrinthine concussion and they may also have been BPPV with it. There can also be the development of post-traumatic endolymphatic hydrops, Meniere's disease, and even migraines. So, someone can have all of these conditions at the same time and or fluctuate out of one or more of these. I know we're trying to categorize dizziness, but as you'll hear me say, once you've seen one patient with dizziness, you've seen one patient with dizziness. So, it's really about putting all these pieces together. And remember, stay tuned about the unicorn. All right, so that wraps it up for video three of lesson two. Only one more video to go. You're in the homestretch. Thanks so much.
Click here to progress to the next blog in this series: Vestibular Rehab | Clinical Tests to Treatment: Benign Paroxysmal Positional Vertigo