BPPV: Case Studies (2/3)

This video is part 2 of 3 of the Interacoustics Webinar "Beyond 2D eye recordings - The importance of measuring torsion and dynamic head movements in the diagnosis and treatment of BPPV” In the second part of this webinar, Dr Michelle Petrak presents four case studies of suspected BPPV, explaining the clinical benefits of utilising torsional eye measurements and dynamic head movements to add diagnostic power to the test battery.

You can read the full transcript below.

Posterior canal BPPV

So here I'm going to show you some examples of patients with different variants of BPPV involving different canals and why it is important that we look at all three of the dimensions of the eye movements including horizontal vertical and torsional eye movements.

Case 1

The first patient is a 75-year-old female with no previous history of dizziness. She complains of getting dizzy when she's getting out of bed and also when she goes from sitting to standing. She feels like the dizziness is stronger when she goes from getting out of bed to standing up than it is when she goes from sitting to standing up.

But either way, she's feeling very insecure. She's afraid that she's gonna fall. So she's now in a wheelchair where she used to be able to walk with a cane before.

She has no symptoms of vomiting and no other history or is not aware of any triggers or anything that might have started this dizziness. So we do a Dix-Hallpike on her, right? So she comes into the clinic. We do the VNG. Everything in the VNG was normal except for what you'll see in the Dix-Hallpike test.

I began with the Dix-Hallpike to the left. She told me that she was more symptomatic to the right, so I decided to go to the left first just to kind of get her used to the procedure and try not to trigger anything too suddenly, which turned out to be a quite a good choice because you can see here that there was no nystagmus triggered here.

And this kind of helped calm her down and get her through the procedure. She's very nervous and you can see here in this tracing that there's three boxes.

So the top box is the horizontal eye movements. The red represents the right eye, and the blue represents the left eye. So she has no horizontal nystagmus.

In the middle box, we see the vertical eye movements. Again, she has no vertical nystagmus.

And in the bottom graph, we see the torsional eye movements. And she doesn't have any torsional eye movements, so this test is negative for BPPV in the left posterior canal.

And then you can see results when we did the Dix-Hallpike to the right. So now you can see that there's a lot of activity here, right? So let's start this video.

And in the very beginning, you see a little bit of noise, that spikey kind of artifact. And that happens sometimes. The patients they want to blink a lot or close their eyes. Sometimes the goggles slip a little bit. And so we have to try to get everything kind of corrected. But once I got her into that position and I held her head steady there, then you can very clearly see that she has right and up beating nystagmus and some torsion present, right?

So she is testing positive for right posterior canal BPPV. So you'll see that there's a right and up beating nystagmus. You can see that the nystagmus diminishes over time.

So if we go back to this video and we fast forward it a bit, you'll see that after about 35 seconds or so, the response starts to slow down. So that's a very good indicator that this is BPPV triggered by the motion or movement of these crystals because the crystals have now settled down due to gravity. So there's no nystagmus.

But then when I set her back up, you can see that the nystagmus returns oftentimes in the opposite direction and not as strong. And this is usually a result of those crystals falling back down when she sits up again, right?

So she meets all the criteria for having BPPV. So she has nystagmus in her horizontal and vertical eye movements. She also has torsion. It diminishes over time as she's held in each position, and it reverses direction when sitting up.

Case 2

Okay, so now let's look at another patient. This is a 55-year-old female. No previous history of dizziness. Her symptoms began in October of last year where she had an acute case of extreme vertigo when leaning her head backwards into the left.

She told me that she was quite surprised by this. It was very scary for her. It was an overwhelming response where the whole room felt like it had gone off spinning. So she waited a few minutes, settled herself down, and it went away. And then just to be sure, she tried it again and turned her head to the left and leaned back again and got that same overwhelming rotary vertigo response.

And so this triggered her to go to the emergency room. They did a Dix-Hallpike test there and found out that she had BPPV. And then they sent her to our clinic where I repeated the Dix-Hallpike test to confirm the BPPV. And then did an Epley maneuver to try to correct it.

And after the Epley maneuver, which you'll see in the next slide, she did have a low-grade headache for a few days, and she felt a little bit off balance. But then we haven't heard from her since, so we assume that everything is fine and corrected now after the Epley maneuver.

So here you see three different pictures, right? These are videos and so I'll play them for you one at a time.

So we can see in the first video, this is her response with her head turned left for the Dix-Hallpike. So this is the left Dix-Hallpike. And you can see that the nystagmus is really big, right? So this is a much stronger response than we saw in the previous patient, right?

Her eyes are bouncing so much that they're almost going outside of the viewing areas she had. And you can see in that bottom right hand graph over 100 degrees per second of torsional nystagmus. So this was a huge response with her head left in the left position and then lying down. Over time it does stop. So you can see that it starts to slow down.

So once the response slows down, then I'm going to move her head now to the right because we're going to start to do that Epley maneuver. So we're going to roll away from the side that's affected. And so you can see that the nystagmus comes back in this position. But it's not as strong and oftentimes it reverses direction. And I held her here in this position for a minute or two, right?

And then we roll her into the final position where her nose is pointing towards the ground. We hold her there for a couple of minutes and then we seat her up. And you can see when she reaches the end of this, about 230 seconds into the test procedure, that she doesn't have any nystagmus present anymore. So we've repositioned those crystals back into the utricle and she, other than that low-grade headache for the first couple of days and a slight off balance, is asymptomatic now.

So this is a very typical way that we would treat the patient when they come in. So we'll first identify the canal and then perform an Epley maneuver to the side away from that canal that's affected, trying to reposition those crystals so the patient can walk away without any symptoms.

Anterior canal BPPV

And now just in contrast, really quick... I just want to show you an anterior canal BPPV. So what you see that's different here... So there's still some horizontal eye movements that we see in that first panel up there. So there's some left beating horizontal nystagmus.

But more importantly, what we see in that middle panel, the vertical eye movements, is now we see some downbeat nystagmus and it's seven degrees. And then in the bottom panel, we still see some torsional eye movements.

So what's different here is that she has down beating vertical nystagmus. And the other two cases were up beating vertical nystagmus. So it's that down beating vertical nystagmus that confirms for us that it's the anterior canal that's involved, not the posterior canal.

Lateral canal BPPV

Okay and so now let's take a look at the next case. This time we're going to be looking at a case of lateral canal BPPV.

Again, a 50-year-old female with no previous history of dizziness. She did say that she had a severe cold or maybe a sinus infection. Shortly afterwards is when she noticed the dizziness when she's moving her head to the right or to the left.

So she gets extremely dizzy when she turns her head either to the right or to the left. This has caused her to stop driving her car because she gets very dizzy when she's looking over her shoulders and she also noted to me that her dizziness is even worse when she's lying down. So she's lying down in bed and turns her head to the right or to the left, the dizziness is even worse.

So here we'll see a video now of the lateral head roll. So she is lying supine. It's a little head model that you see in the bottom right-hand corner. That's to show that we have her head positioned at the right angles on each side. So try to get the same head motion to both sides and then what we'll see in the video.

So we're gonna first turn our head to the right. And then when we're at the correct angle, 45 degrees, then that bar lights up green. That's just to let me know that I'm in the right angle. So I've positioned her head correctly. So that's the what the model is there for. It's very practical, especially when you're doing the posterior canals.

And so here we can see when her head is turned to the right that she has a very nice right beating nystagmus. There might be a couple of vertical beats there too. But a really nice clear right beating nystagmus.

Now I turn our head to the left and the nystagmus changes direction. So now I have a left beating nystagmus. So this confirms for me that she has a lateral canal BPPV. And the side with the stronger nystagmus, that's just the side that's most likely affected, right? So we'll just let this video play out.

Okay, and then now we can see that in the head position to the right, she has six degrees. And when we roll her head to the left, she has 11 degrees. So it's a stronger response to the left. So this indicates or confirms for us that this patient has left horizontal or lateral canal BPPV.

BPPV or central positional nystagmus?

So now let's take a look at the next case. This time we're going to look at differentiating what is BPPV from what is a central positional nystagmus.

This is a 64-year-old female. Again, no previous history of dizziness. Her biggest complaint since August is that she has started to feel very fatigued and that she's had some headaches, and she has some motion sensitivity when moving her head or getting up and down.

So she's not complaining of that spinning sensation or telling us that the room is spinning like we heard from the previous patients that had posterior canal BPPV. But she's complaining of just feeling a little sensitive to motion, fatigued, and having some headaches. She did have an MRI which was unremarkable.

So the first thing that we do is just look to see if she has any spontaneous nystagmus present. And so here we can see that with the goggles on, the covers on, so she's just sitting in the dark with her eyes open, we don't really see any nystagmus.

Maybe ever so slightly a few may look like very tiny beats. But they're so small that that the algorithm doesn't even pick them up. So they'd have to be like less than a half degree. So they're really insignificant.

And so if we watch the video... When we look at her eyes, they really look quite steady, right? So I'm not seeing any red flags for any spontaneous nystagmus here. So then the next thing that we would do is the Dix-Hallpike.

So here I'm doing just the traditional Dix-Hallpike, which means that I don't have the IMU sensor on the goggles and I'm not measuring or recording the torsional eye movements. I'm just looking at what's happening in the horizontal and the vertical channels. So is there horizontal nystagmus and is there vertical nystagmus?

And what we can see is that when we do the Dix-Hallpike to the left, she has some left beating nystagmus. It's significant. It's 10 degrees. And very little if any nystagmus in the vertical channel there. Might be just a couple of upbeats there around 23 to 25 seconds. But nothing really significant.

And then when we do the Dix-Hallpike to the right, we see that she has some right beating horizontal nystagmus, but no vertical nystagmus is recorded at all here, right? So if there is a little bit of vertical nystagmus there, it's so small. Less than a half degree. So the software is not picking it up. So clearly no significant vertical nystagmus present.

So this now kind of leaves me with a little bit of a question in my mind: Is this really BPPV or not? Because it doesn't really have that traditional strong up or down beating component that we saw in the other cases and so it's really hard for me to make a final assessment here without having that torsional component.

So if I then move into the Advanced Dix-Hallpike where I can measure the torsion. I put that sensor back onto the goggle and I activate my torsional algorithm. Now I get a little bit more confirmation here that this probably is not BPPV because you can see in that bottom panel, there's no torsional nystagmus present.

So again, having this extra dimension to look at, being able to look at those torsional eye movements, it adds value and helps us to make a more confident diagnosis.

And so here I noticed that the nystagmus wasn't fatiguing. And if you remember again, in the cases where we had the BPPV, we showed that after 30 to 50 seconds or so into the test, that the nystagmus would fatigue until we moved the patient again. So we don't see that here. We're not seeing any torsional nystagmus. So two indicators for BPPV are missing.

But just to be certain, we went ahead, and we tried to do a corrective maneuver. An Epley maneuver to see if we missed something or if there was something there that we're not picking up. But after doing the corrective maneuvers, there's no change in the parameters of the nystagmus. So the maneuvers are having no effect.

So all of this points to the fact that this is not BPPV caused by the moving crystals but more of a central positional nystagmus that has to do with the patient putting their head into different positions.

Central vestibular lesion

Okay, and then let's take a look at the final case. Again, another central vestibular lesion. So this is a 36-year-old male that's being treated for multiple sclerosis. He has had recent complaints of dizzy spells. He cannot associate them with any specific trigger.

So I always ask my patients if they have a trigger, if they know of something that they do or something that triggers that dizziness. And he didn't have any explanation that he could give me for anything that would trigger the dizziness. He did say that it was intermittent and that it had started about two months ago.

What we notice right away that's remarkable in this gentleman is that he has a pure torsional nystagmus. So he has a torsional nystagmus present when he's just sitting and not doing anything. So we see here that he has no activity, no motion, no nystagmus present. At least nothing significant in the horizontal and vertical channels.

But he has quite a significant torsional nystagmus present in the bottom panel. So what we see again, he's just sitting still, and we see this torsional nystagmus without any horizontal and vertical components. So a pure torsional nystagmus. That would require involvement of the connections from both vertical canals from one labyrinth.

This is a very rare finding. So we don't see this very often in the clinic. It usually has to do with some kind of a central imbalance between the connections of the vertical semicircular canals. We can see some fast phase intorsion or extorsion that is usually conjugate and symmetric.

But what we don't see is activity in the horizontal and vertical channels. So no left, right, up, or down beating nystagmus. Just that pure torsion. And this is our trigger that this is a central finding. So this is a red flag for a further central workup. And oftentimes, this pure torsion can come from a lesion in the midbrain.

The rest of the VNG was unremarkable with the exception of the gaze test. So we see something very interesting here also. So we can see in his gaze test that there is some nystagmus present there. And it's significant at six degrees. So we see six degrees of left-beating nystagmus in the right eye when he gazes to the left. So there's an internuclear ophthalmoplegia (INO) or some difference in the motion or the movement of the eyes.

And then there's the asymmetrical unilateral right gaze evoked nystagmus. So when we look at this video, we can see while he's gazing to the left, the left eye is pretty stationary, but the right eye has a clear nystagmus. And this again is another central finding.

So in this gentleman, what we see is no positioning nystagmus. He has an INO. He has an asymmetrical unilateral right eye only gaze evoked nystagmus and pure torsion. So these are all indicators that this is a central lesion. And since he's a patient being treated for multiple sclerosis, it's very likely that this is attributed to his multiple sclerosis.

Take home messages

So in conclusion, I would just like to leave you with one take-home message. And I hope after reviewing all these cases that you can see it's very important to analyze all three dimensions of the eye movements. And we want to look at horizontal, vertical, and torsional eye movements because that will help us to differentiate between what is truly a BPPV and what is a position nystagmus or a central lesion.

Related courses

• Advances in BPPV
• BPPV: The importance of torsion and performing the maneuvers correctly