Hi, I'm Helena Esmonde, vestibular physical therapist and co-founder of Vestibular First. I appreciate your investment of time and energy into learning how to improve patient care for those with dizziness, vertigo, or imbalance. In this video I'll take a few minutes to share and discuss two patient cases which include eye movement videos to add to your opportunities for interpreting eye movements as part of the vestibular diagnostic process. Our first patient is in her 80s and about seven years ago she experienced a significant vertigo event. She went to the emergency department where they did an MRI of her head which was negative for any abnormalities. She went home, saw her primary care physician, and they told her "there's something funny with your eyes", which have been that way ever since. In this video the patient is seated at rest. She has a spontaneous downbeat nystagmus which sometimes has a left torsion to it most notably with left gaze, but it is generally downbeat in nature. The patient has had MRI imaging a few times in the past seven years and there's no tumor, Chiari malformation, multiple sclerosis, or anything else that would explain the downbeat nystagmus. I spoke with the patient's neurologist about this and they have said it is likely due to an old cerebellar stroke that just didn't show on the MRI of the head done seven years ago due to the way it was sliced. Luckily the patient is already pretty habituated that she has only mild dizziness and imbalance. She can walk safely with a cane. We will call this the patient's baseline nystagmus. Unfortunately for this patient, sometimes she gets BPPV. I think she's had it about once a year since I met her a few years ago. When she gets BPPV she does not feel spinning or dizziness with position changes. Rather she just gets very nauseous in a way that is constant. We do know from the literature that patients do not have to experience a spinning sensation with position changes to have BPPV even though such a report is common. The type of nausea this patient has could be mistaken for a GI issue. With repeat events and negative workup for GI issues, she has learned that it is a cue that she likely has had a recurrence of BPPV. In this video, the patient is in the left Dix Hallpike position. As soon as I convince her to open her eyes you can see that she has a left torsional upbeat nystagmus. It's pretty brisk and lasting about 10 to 15 seconds. This is a classic presentation of left posterior canal canalithiasis, where the otoconia are freely floating in the left posterior canal. She responds very well to left-modified Epley Maneuvers applied over a session or two. This case is a really great example where I know I need to use infrared video goggles because in room light I would see little or no nystagmus since the upbeat torsional eye movements due to the BPPV are essentially canceled by the competing downbeat related to the prior cerebellar stroke. This is also a great example of a patient where it isn't a question of do they have a central vestibular issue or a peripheral vestibular issue because this patient has both. This is a case where I need to see everything that is going on as far as types of nystagmus to make sense of everything I see. Having the recordings also makes it easy for me to discuss this case with other providers such as the patient's neurologist or someone that might be mentoring me. I have learned that this patient usually needs to be seen once a week for another four to six weeks, give or take, after an episode of BPPV, where we can apply balance training and habituation to restore her to her prior level of function. It's not unusual for a patient with a prior underlying central vestibular condition, such as a cerebellar stroke or brain injury for example, to take more time than most people to fully return to feeling at baseline after BPPV has been cleared. Our second case involves a patient with a history of concussion. I've treated her a few times for BPPV which happens in about a third of patients after concussion even if it is remote. In this video you can see that I recorded the room so we know what test I am doing just by watching. I have the patient in a supine roll test with the patient's head to the right This patient has a nice dark spot on her right iris which can be helpful to follow as we try to identify the direction of any nystagmus. You can see that after a few seconds of latency the patient has a left horizontal beat nystagmus. We usually call this an apogeotropic or angiotropic nystagmus, so the nystagmus is beating away from the ground. I'm considering the diagnosis of horizontal canal cupuolithiasis, but we need to see what happens the other side of the roll test first. Now let's watch a video of the left side of the roll test. The patient has a right horizontal nystagmus, which is again considered apogeotropic and would be consistent with a horizontal canal cupuolithiasis. However, neither nystagmus looked particularly weaker than the other side which is how I've been trained to identify the affected sides with horizontal canal cupuolithiasis. In addition, this patient reported feeling mildly nauseous throughout the testing without any particular difference in symptom levels during the right versus left portions of the supine roll test. This gives us a great opportunity to perform the bow and lean test or a supine tp sit test would be an alternative as well. I'll show you the lean portion of the bow and lean test first since for the lean portion of the test, the nystagmus should be towards the affected side in a patient with horizontal canal cupuolithiasis. Usually you would have the patient lean their head back with neck extension, but she started complaining of neck discomfort at this point so I modified the test to use back extension to get the head and vestibular apparatus in the position we need. We do what we need to do to get the information we need safely. Here you can see that the patient has a right horizontal beaten nystagmus indicative of right horizontal canal cupulolithiasis. Just to confirm we are dealing with a peripheral vestibular issue, I did perform the bow test. We do want to see the nystagmus follow all the rules to improve our confidence that this nystagmus is from a peripheral vestibular issue, and not from the central vestibular issue or a vascular problem that would be mimicking BPPV. You can see that in this bow test as expected, the patient has a brisk left horizontal nystagmus which is beating away from the affected side. For the patient who has a right horizontal canal cupulolithiasis. It's very helpful to have infrared video goggles which allow us to see the mild nystagmus that we saw in the second patient case during the supine roll tests. This type of nystagmus could be easily suppressed in room light. It's also really helpful to be able to look at my computer screen to see the nystagmus instead of trying to duck down or climb up to see the patient's eyes during the bow and lean test. Overall, I hope these two patient cases provided a good opportunity for you to review types of nystagmus and how we can use infrared video goggles to see eye movements that we may otherwise miss when examining patients with dizziness, vertigo, or imbalance. Please be sure to visit the educational page on our website vestibularfirst.com and register for our free monthly Journal Clubs. We also have a free quarterly newsletter and other resources, so check those out as well! Thanks so much and wishing you all the best as you continue along your own professional journey. Go team vestibular!