Continuum Audio

Ajay Madhavan, a neuroradiologist at the Mayo Clinic with expertise in spinal CSF leaks, joins the conversation to shed light on groundbreaking myelographic techniques for detecting spontaneous intracranial hypotension. He explains the various types of CSF leaks and their imaging findings, emphasizing the challenges in diagnosis. The discussion also covers the evolution of myelography, advancements like photon counting detector CT, and the integration of AI tools to improve diagnosis, encouraging clinicians to communicate effectively with patients.

Dr. Jill Rau, an assistant professor of clinical neurology and headache medicine expert, discusses the complexities of spontaneous intracranial hypotension. She highlights the disruption of cerebrospinal fluid dynamics that can lead to debilitating issues, including chronic headaches and cognitive impairment. The conversation delves into diagnostic challenges, the importance of recognizing this condition, and innovative treatment approaches like blood patches. Rau sheds light on brain sagging dementia's link to this disorder, underscoring its profound impact on patients' lives.

In this episode, Lyell K. Jones Jr, MD, FAAN, speaks with Jeremy K. Cutsforth-Gregory, MD, FAAN, who served as the guest editor of the June 2025 Disorders of CSF Dynamics issue. They provide a preview of the issue, which publishes on June 2, 2025. Dr. Jones is the editor-in-chief of Continuum: Lifelong Learning in Neurology® and is a professor of neurology at Mayo Clinic in Rochester, Minnesota. Dr. Cutsforth-Gregory is an associate professor in the department of neurology at Mayo Clinic in Rochester, Minnesota. Additional Resources Read the issue: continuumjournal.com Subscribe to Continuum®: shop.lww.com/Continuum Continuum® Aloud (verbatim audio-book style recordings of articles available only to Continuum® subscribers): continpub.com/Aloud More about the American Academy of Neurology: aan.com Social Media facebook.com/continuumcme @ContinuumAAN Host: @LyellJ Guest: @JCGneuro Full episode transcript available here Interview with Jeremy Cutsforth-Gregory, MD Dr Jones: Most of the time when neurologists think about cerebrospinal fluid or CSF, we're thinking about getting a sample so we can test it for biomarkers of infection or inflammation, tumors, more recently neurodegenerative diseases. But there are many patients for whom the CSF isn't a clue to the problem---it is the problem. Today I have the opportunity to interview Dr Jeremy Cutsforth-Gregory, who is the guest editor of our first-ever issue at Continuum on disorders of CSF dynamics. Dr Jones: This is Dr Lyell Jones, Editor-in-Chief of Continuum. Thank you for listening to Continuum Audio. Be sure to visit the links in the episode notes for information about subscribing to the journal, listening to verbatim recordings of the articles, and exclusive access to interviews not featured on the podcast. Dr Jones: This is Dr Lyell Jones, Editor-in-Chief of Continuum: Lifelong Learning in Neurology. Today I'm interviewing Dr Jeremy Cutsforth-Gregory, who recently served as Continuum's guest editor for our latest issue, which covers disorders of CSF dynamics. Dr Cutsforth-Gregory is an associate professor in the Department of Neurology at Mayo Clinic in Rochester, Minnesota, where he's also the director of the Mayo Clinic CSF Dynamics Clinic and an assistant dean of career advising at the Mayo Clinic School of Medicine. Dr Cutsforth-Gregory, welcome, and thank you for joining us today. Why don't you introduce yourself to our listeners? Dr Cutsforth-Gregory: Thank you so much, Dr Jones. I'm excited to be here and really privileged to have served as the guest editor for this first issue devoted to CSF dynamics. You mentioned my title as director of the CSF Dynamics Clinic, in which we brought together what we think of as the full spectrum of disorders where pressure or flow of the fluid around the central nervous system is off. So, we do CSF leaks, we do intracranial hypertension and normal pressure hydrocephalus, and from that have been able to gain quite a few insights that I'm excited to share with you today. Dr Jones: Yeah. And I'm really grateful for your time. I'm really grateful for this issue. You know, we all learn about disorders of CSF flow in training, but my impression---and maybe you share it, Dr Cutsforth-Gregory---is that many of these patients fall through the cracks. I think there's probably many reasons for this. I think it's in part because some aspects of this practice are relatively new or they're changing rapidly, or some of the disorders are uncommon. And I think many of these require a high degree of coordination between neurologists and neurosurgeons and radiologists. So we thought a Continuum issue dedicated to this would help close some practice gaps that we're pretty confident are out there. I'm really grateful for your leadership of it, and I think it'll come in handy for junior readers and even our more experienced listeners as well. And let's get right to it. You've had a chance now to review all of the articles in the issue and, you know, the latest in the field. What's the biggest thing that you would like to see change in the care of these patients? Dr Cutsforth-Gregory: I think you're right that there is often delay in diagnosis, incorrect diagnosis, misdiagnosis, really across the spectrum of the low pressure, high pressure and normal pressure disorders. And that's what I'd like to see change with this issue, is increased awareness of the really myriad presentations that spontaneous intracranial hypotension can have. It's not all orthostatic headache, although that's common. Similarly, idiopathic intracranial hypertension is misdiagnosed in a third or more cases presenting to ophthalmology clinics. So, it's not just papilledema, high pressure in a certain demographic. And I think the article by Dr Aileen Antonio really goes into the details on how to make an accurate diagnosis and not miss these and not mistreat them. And normal pressure hydrocephalus, the pendulum has really swung between whether this is an entity or isn't an entity. It is. It's patients we can help. The imaging findings are surprisingly common, and the disorder is probably somehow both overcalled on CT scans of the head---cannot rule out normal pressure hydrocephalus, clinical correlation required, we've all seen that report---but also missed opportunities to help patients who have treatable gait, cognitive and bladder disorders. So, if we could improve awareness and increase the accuracy of diagnosis on these three disorders, I will say the mission has really been moved forward. Dr Jones: Thanks for that. Let's start with NPH because again, over my career, I have seen the pendulum swing back and forth in terms of awareness of this disorder and thresholds for diagnosis. What's our latest in terms of the understanding of normal pressure hydrocephalus and how should our listeners think about the approach to diagnosing these patients? Dr Cutsforth-Gregory: I think we all learn that NPH is dementia, gait disorder and urinary incontinence, and that hasn't changed. A good chunk of these patients, perhaps half or more, don't have the full triad, and you do not have to have the full triad for the diagnosis or to justify intervention with permanent CSF diversion through shunt placement. And so, being open to the diagnosis in a patient with a gate apraxia, which is usually the first leading present presenting change which is a gait disorder. Cognitive changes follow that, bladder comes along the way. So, I think anytime you see someone with an unexplained gait disorder that has apraxic features, short steps, three steps to turn, can look a little Parkinsonian but you don't have other Parkinsonism on exam necessarily, we should be thinking about NPH and ordering a good-quality head imaging to look for those features. Dr Jones: Yeah, thanks for that point, Jeremy. It does seem like the pendulum has swung back and forth on the diagnosis of this disorder. And I think in many ways it comes down to having good diagnostic biomarkers. A term that I know… I was only made aware of it a few years ago: disproportionately enlarged subarachnoid space hydrocephalus, or DESH. So, tell us a little bit more about that. It's not just about the ventricles, right? Dr Cutsforth-Gregory: That's exactly right. So, we think hydrocephalus, that means ventriculomegaly, and it does, but DESH, as you said, the mouthful “disproportionately enlarged subarachnoid space hydrocephalus”, is basically CSF accumulation around the brain outside the ventricles. Common features would be enlarged Sylvian fissures, focally dilated sulci, and then at the same time, up high on the convexity, tight sulci. So, it's this combination; there's clearly a flow problem where CSF is being trapped in certain areas outside the brain and excluded from others. And that is a common feature. And that alone predicts a positive response to shunt surgery. Dr Jones: I remember the first time one of my colleagues pointed that out to me on an image, and it just made me wonder how many times I had missed it before that point in my career. But that's the point, is to learn and move forward. One of the common themes, I think, in this practice, one of the common themes in this issue, is the interdisciplinary work that's necessary not just for treating patients with CSF dynamics disorders, but also the diagnosis. We really do have to work carefully and closely with neurosurgeons and with radiologists. And to reflect that we had a pretty diverse group of authors. Moreso, I think, that we usually do for Continuum, given the overlap with the radiology and surgical practice. As you were reviewing these articles, were there any unique or distinctive perspectives that you saw come through? Dr Cutsforth-Gregory: Absolutely. And I have to say, I'm so proud of the diverse author panel we were able to put together: as you said, including clinicians, but also neuroradiologists; neurosurgeons, both adult and pediatric; as well as a couple- an ENT surgeon to talk about those cranial skull base leaks. So, we really brought together what we think is necessary to take care of these patients. As far as unique perspectives here, I would point to the article on diagnosis, surgical treatment, the long term implications of atraumatic cranial CSF leaks. So, these are the patients who present with CSF otorrhea or rhinorrhea and do not have a history of skull base surgery or trauma to explain it. That is often a chronic intracranial hypertension patient who, instead of staying sealed up and building up pressure and presenting with papilledema and headaches, had a leak. And that's relevant because, after it’s fixed, that patient needs to come to us in neurology to be monitoring for papilledema, measure lumbar puncture, open pressure. And we've developed that as part of our workflow with our colleagues in neurosurgery and ENT who seal those leaks, because that's a patient who is at high risk of recurrent leak if we don't treat the underlying high pressure disorder. That's a new concept, I think, for many of us. And so, to be able to put that front and center in an article, in an issue for practicing neurologists, I think, is really important, and it's something we haven't been able to do before. Similarly, the article by Dr Olga Fermo on the treatment of persistent symptoms after normalization of CSF pressure. We've all taken care of patients who had a CSF leak or had hypertension, and it seems like those issues are resolved, and yet they still have headaches. The IIH treatment trial taught us that that happens in perhaps two thirds of patients with IIH. And so, to have Dr Fermo's article on how to help those patients manage the headaches when the CSF disorder seems to have been resolved, I think it's super useful. The last one I would mention is just the final one by Dr Shenandoah Robinson, a pediatric neurosurgeon, talking about child onset hydrocephalus. And so, NPH is the focus of most of those other articles. But the patients who we will take care of as adult neurologists, child neurologists, whose issue really started early on, it’s important that we stay involved and how to do that, what things we should be watching for, when to suspect shunt malfunction, it’s all covered in Dr Robinson's article, and it’s a unique one for this issue. Dr Jones: It's always interesting to read articles, as a neurologist, that are written by a neurosurgeon because, you know, they have a different perspective, right? T're intervening on the anatomy, and just hearing how they think about these things was illuminating for me. The article on atraumatic cranial skull base CSF leaks, that connection with intracranial hypertension, I was unaware of that. So that was a good learning point for me. And while we're still on the too-high-pressure problem of idiopathic intracranial hypertension, do we have any more insight into what causes that? What's the mechanism of that disease? Do we know any more than we used to? Dr Cutsforth-Gregory: We know more than we used to. We certainly don't understand all of it. But rather than just a disease of reproductive-age women carrying extra weight, it is now recognized as, really, a metabolic and hormonal-driven condition. And it's relevant because it really highlights new ways to intervene and to treat these patients. The GLP-1 inhibitors may have a role, considering some of the comorbidities like polycystic ovary syndrome and the hormonal connections. The patients who perhaps are female-to-male trans, who then can present with intranial hypertension, and how we can help them without needing to take them off gender confirming hormone therapy, is all really relevant to help us help more patients by having that broader understanding of the cause of disease, that it’s not just weight gain/weight loss. Dr Jones: Fantastic, and very useful to know. Thinking of the other end of the spectrum, right, rather than too much CSF or too much CSF pressure… I know this has been a focus of your academic work, Dr Cutsforth-Gregory. We also have disorders of CSF hypotension where the pressure is too low, and that this is usually reflective of a dural defect. I know in my own practice, sometimes, these are very difficult to find, and that's really- as you said, diagnosis is the first step, but then we have to find the problem and try to direct surgeons where to go to repair it. Do you have any tips for our listeners on how to approach the hunt for the source of CSF leaks? Dr Cutsforth-Gregory: Absolutely. And I first have to give a call out to my mentor, Dr Bahram Mokri, who is the one who first reported the diffuse sterile enhancement, back in the early 1990s, that marks some, but not all, patients with spontaneous intracranial hypotension. He would also remind me that that's not a good term to call it, even though I just did and I will continue to do it intermittently. Because really, this is an underlying spinal CSF leak or a CSF venous fistula. And the problem is not too-low pressure, which is why hypotension is probably not the best word, but too-low volume. It's intracranial CSF hypovolemia. You know, with the opportunity that Dr Mokri gave me to see some of those patients with him and become intrigued by it, it is the bulk of my clinical practice, my research focus, and the conversations I get to have every single day with neuroradiologists and neurosurgeons. I tell patients, it is a field that is moving incredibly quickly and that, when I see them again in a few months or the next year, for whatever reason, I always joke and I say, I reserve the right to have different recommendations, because it is moving. I finished residency in 2014, which is the year CSF fistulas were first reported. I'm sure they existed before that. So, it was a lack of awareness. And so, look for what you know. Now we know to look for fistulas. You find what you look for; we've developed a number of new myographic techniques to find these things, and they are now the majority of the type of leak that we find. So, it is a patient population where we were missing more than we were hitting ten years ago. And now maybe that's still true, but we're certainly finding a lot more than we used to because of those collaborations. Dr Jones: Thinking back to DESH, right? Once you're aware that it is something that can be identified, you start to see it more and more. And again, that's how we move the field forward. And again, the CSF venous fistula story is one that I know was relatively new to me and something I learned a lot about reading through the issue. And hopefully our readers and our listeners find some insights and benefits there. This is a rapidly changing field. This may be a hard question to answer, but when you look into the future, what are some of the changes on the horizon in this practice? Dr Cutsforth-Gregory: See, I'll probably point to the- both diagnosis and treatment. We're recognizing that it's, like I said earlier, not all orthostatic headache, but some of the other manifestations, such as frontotemporal brain sagging syndrome, can be a manifestation of leak. So, suspected leak is the first step. Then you have to look for it. And MRI will change, you know, incrementally, I'm sure; we'll get higher resolution pictures. But the C wave of change is going to be in how to do the myelogram, what imaging modality we use; and the newest kit on the block, if you will, is photon-counting detector CT myelography. That's a different kind of CT scanner than we've been used to over the last few decades. It detects light energy differently. It allows better signal-to-noise ratio, faster acquisition of scans. And so, using that allows us to get thinner slices through the spine to look for leaks and fistulas. I think photon CT will become more widespread because it has applications well beyond neurology and just myelograms. And so, as those scanners become more available, everyone will get to be better at finding these leaks. And then treatment, I'll highlight a procedure called transvenous paraspinal vein embolization. You know, a CSF venous fistula is an abnormal connection between a nerve root sleeve and a vein. And the CSF is escaping up through the that vein in an unregulated fashion. And historically when those were found, the treatment was to ligate the nerve root. Get rid of the nerve root sleeve, you get rid of the abnormal connection, you get rid of the vein, you stop the leak. And that is effective. A number of studies have shown that. But it's also invasive; it requires a laminectomy and losing a nerve root. You can't do that at every level of the spine, right? This is predominantly thoracic, and only if you're away from the artery of Adamkiewicz. But a few years ago, Dr Walid Benjigchi pioneered a procedure of going through the vein and embolizing it, putting in a liquid embolic agent that seals it off. The nerve root stays attacked. We can do it at every level of the spine, and it's an outpatient, endovascular procedure to fix fistulas. That kind of minimally invasive procedure for fistulas has been a major shift away from the open surgeries. We will, I think, make advances with new catheters and new needles to be able to do some other kind of minimally invasive procedures for the other kinds of leaks. I think that's what we'll be seeing, is less and less invasive procedures on the leak side. Dr Jones: Great summary there. Thank you. So, it sounds like a combination of hopefully improved clinician awareness, which will improve diagnostic recognition; more sensitive tools like the photon counting CTS; and less invasive definitive therapies, which I think is promising for the field. And you've led a lot of that work, Dr Cutsforth-Gregory, over the last few years. When you see these patients, I'm sure it's rewarding to see patients with previously poorly-recognized or misunderstood symptoms get better. Is that the most rewarding part of this practice for you, or what can you tell me about your experience in the care of these patients? Dr Cutsforth-Gregory: You know, I'm a curious person. I like to learn. So, I will say it is really rewarding to develop a new technique and put it into practice and see it increase our hit rate on finding these leaks and helping these patients. But nothing beats the feeling of taking a patient who's been stuck in bed or saying that they can't function and they're out of work or out of their family life, and getting that Christmas card or that hug that says they're back. But, you know, we're here to help our patients, and nothing can beat that feeling. Dr Jones: I think that's a great point to end on. Dr Cutsforth-Gregory, thank you for joining us. Thank you for such a detailed discussion of a broad, diverse topic. I learned a lot today---some things that I wasn't aware of, having read the issue---and hopefully our listeners did, too. Dr Cutsforth-Gregory: Thank you so much, Dr Jones. Dr Jones: Again, we've been speaking with Dr Jeremy Cutsforth-Gregory, Guest Editor of Continuum's first-ever issue focusing on CSF dynamics. Please check it out. And thank you to our listeners for joining today. Dr Monteith: This is Dr Teshamae Monteith, Associate Editor of Continuum Audio. If you've enjoyed this episode, you'll love the journal, which is full of in-depth and clinically relevant information important for neurology practitioners. Use the link in the episode notes to learn more and subscribe. Thank you for listening to Continuum Audio.

As artificial intelligence (AI) tools become increasingly mainstream, they can potentially transform neurology clinical practice by improving patient care and reducing clinician workload. Critically evaluating these AI tools for clinical practice is important for successful implementation. In this episode, Katie Grouse, MD, FAAN speaks with Peter Hadar, MD, MS, coauthor of the article “Clinical Applications of Artificial Intelligence in Neurology Practice” in the Continuum® April 2025 Neuro-ophthalmology issue. Dr. Grouse is a Continuum® Audio interviewer and a clinical assistant professor at the University of California San Francisco in San Francisco, California. Dr. Hadar is an instructor of neurology at Harvard Medical School and an attending physician at the Massachusetts General Hospital in Boston, Massachusetts. Additional Resources Read the article: Clinical Applications of Artificial Intelligence in Neurology Practice Subscribe to Continuum®: shop.lww.com/Continuum Continuum® Aloud (verbatim audio-book style recordings of articles available only to Continuum® subscribers): continpub.com/Aloud More about the American Academy of Neurology: aan.com Social Media facebook.com/continuumcme @ContinuumAAN Guest: @PeterNHadar Full episode transcript available here Dr Jones: This is Dr Lyell Jones, Editor-in-Chief of Continuum. Thank you for listening to Continuum Audio. Be sure to visit the links in the episode notes for information about subscribing to the journal, listening to verbatim recordings of the articles, and exclusive access to interviews not featured on the podcast. Dr Grouse: This is Dr Katie Grouse. Today I'm interviewing Dr Peter Hadar about his article on clinical applications of artificial intelligence in neurology practice, which he wrote with Dr Lydia Moura. This article appears in the April 2025 Continuum issue on neuro-ophthalmology. Welcome to the podcast, and please introduce yourself to our audience. Dr Hadar: Hi, thanks for having me on, Katie. My name is Dr Peter Hadar. I'm currently an instructor over at Mass General Hospital, Harvard Medical School, and I'm excited to talk more about AI and how it's going to change our world, hopefully for the better. Dr Grouse: We're so excited to have you. The application of AI in clinical practice is such an exciting and rapidly developing topic, and I'm so pleased to have you here to talk about your article, which I found to be absolutely fascinating. To start, I'd like to hear what you hope will be the key takeaway from your article with our listeners. Dr Hadar: Yeah, thank you. The main point of the article is that AI in medicine is a tool. It's a wonderful tool that we should be cautiously optimistic about. But the important thing is for doctors, providers to be advocates on their behalf and on behalf of their patients for the appropriate use of this tool, because there are promises and pitfalls just with any tool. And I think in the article we detail a couple ways that it can be used in diagnostics, in clinical documentation, in the workflow, all ways that can really help providers. But sometimes the devil is in the details. So, we get into that as well. Dr Grouse: How did you become interested in AI and its application, specifically in the practice of neurology? Dr Hadar: When I was a kid, as most neurologists are, I was- I nerded out on a lot of sci-fi books, and I was really into Isaac Asimov and some of his robotics, which kind of talks about the philosophy of AI and how AI will be integrated in the future. As I got into neurology, I started doing research neurology and a lot of folks, if you're familiar with AI and machine learning, statistics can overlap a lot with machine learning. So slowly but surely, I started using statistical methods, machine learning methods, in some of my neurology research and kind of what brought me to where I am today. Dr Grouse: And thinking about and talking about AI, could you briefly summarize a few important terms that we might be talking about, such as artificial intelligence, generative AI, machine learning, etcetera? Dr Hadar: It's a little difficult, because some of these terms are nebulous and some of these terms are used in the lay public differently than other folks would use it. But in general, artificial intelligence is kind of the ability of machines or computers to communicate independently. It’s similar to as humans would do so. And there are kind of different levels of AI. There's this very hard AI where people are worried about with kind of terminator-full ability to replicate a human, effectively. And there are other forms of narrow AI, which are actually more of what we're talking about today, and where it's very kind of specific, task-based applications of machine learning in which even if it's very complex, the AI tools, the machine learning tools are able to give you a result. And just some other terms, I guess out there. You hear a lot about generative AI. There's a lot of these companies and different algorithms that incorporate generative AI, and that usually kind of creates something, kind of from scratch, based on a lot of data. So, it can create pictures, it can create new text if you just ask it. Other terms that can be used are natural language processing, which is a big part of some of the hospital records. When AI tools read hospital records and can summarize something, if it can translate things. So, it turns human speech into these results that you look for. And I guess other terms like large language models are something that also have come into prominence and they rely a lot on natural language processing, being able to understand human speech, interpret it and come up with the results that you want. Dr Grouse: Thank you, that's really helpful. Building on that, what are some of the current clinical applications of AI that we may already be using in our neurologic practice and may not even be aware that that's what that is? Dr Hadar: It depends on which medical record system you use, but a very common one are some of the clinical alerts that people might get, although some of them are pretty basic and they can say, you know, if the sodium is this level, you get an alert. But sometimes they do incorporate fancier machine learning tools to say, here's a red flag. You really should think about contacting the patient about this. And we can talk about it as well. It might encourage burnout with all the different flags. So, it's not a perfect tool. But these sorts of things, typically in the setting of alerts, are the most common use. Sorry, and another one is in folks who do stroke, there are a lot of stroke algorithms with imaging that can help detect where the strokes occur. And that's a heavy machine learning field of image processing, image analysis for rapid detection of stroke. Dr Grouse: That's really interesting. I think my understanding is that AI has been used specifically for radiology interpretation applications for some time now. Is that right? Dr Hadar: In some ways. Actually, my background is in neuroimaging analysis, and we've been doing a lot of it. I've been doing it for years. There's still a lot of room to go, but it's really getting there in some ways. My suspicion is that in the coming years, it’s going to be similar to how anesthesiologists at one point were actively bagging people in the fifties, and then you develop machines that can kind of do it for you. At some point there's going to be a prelim radiology read that is not just done by the resident or fellow, but is done by the machine. And then another radiologist would double check it and make sure. And I think that's going to happen in our lifetime. Dr Grouse: Wow, that's absolutely fascinating. What are some potential applications of AI in neurologic practice that may be most high-yield to improve patient care, patient access, and even reduce physician burnout? Dr Hadar: These are separate sort of questions, but they're all sort of interlinked. I think one of the big aspects of patient care in the last few years, especially with the electronic medical record, is patients have become much more their own advocates and we focus a lot more on patient autonomy. So, they are reaching out to providers outside of appointments. This can kind of lead to physician burnout. You have to answer all these messages through the electronic medical record. And so having, effectively, digital twins of yourself, AI version of yourself, that can answer the questions for the patient on your off times is one of the things that can definitely help with patient care. In terms of access, I think another aspect is having integrated workflows. So, being able to schedule patients efficiently, effectively, where more difficult patients automatically get one-hour appointments, patients who have fewer medical difficulties might get shorter appointments. That's another big improvement. Then finally, in terms of physician burnout, having ambient intelligence where notes can be written on your behalf and you just need to double-check them after allows you to really have a much better relationship with the patients. You can actually talk with them one on one and just focus on kind of the holistic care of the patient. And I think that's- being less of a cog in the machine and focusing on your role as a healer would be actually very helpful with the implementation of some of these AI tools. Dr Grouse: You mentioned ambient technology and specifically ambient documentation. And certainly, this is an area that I feel a lot of excitement about from many physicians, a lot of anticipation to be able to have access to this technology. And you mentioned already some of the potential benefits. What are some of the potential… the big wins, but then also potential drawbacks of ambient documentation? Dr Hadar: Just to kind of summarize, the ambient intelligence idea is using kind of an environmental AI system that, without being very obtrusive, just is able to record, able to detect language and process it, usually into notes. So, effectively like an AI scribe that is not actually in the appointment. So, the clear one is that---and I've seen this as well in my practice---it's very difficult to really engage with the patient and truly listen to what they're saying and form that relationship when you're behind a computer and behind a desk. And having that one-on-one interaction where you just focus on the patient, learn everything, and basically someone else takes notes for you is a very helpful component of it. Some of the drawbacks, though, some of it has to do with the existing technology. It's still not at the stage where it can do everything. It can have errors in writing down the medication, writing down the exact doses. It can't really, at this point, detect some of the apprehensions and some of the nonverbal cues that patients and providers may kind of state. Then there's also the big one where a lot of these are still done by startups and other companies where privacy may be an issue, and a lot of patients may feel very uncomfortable with having ambient intelligence tools introduced into their clinical visit, having a machine basically come between the doctor and the patient. But I think that over time these apprehensions will lessen. A lot of the security will improve and be strengthened, and I think that it's going to be incorporated a lot more into clinical practice. Dr Grouse: Yeah, well, we'll all be really excited to see how that technology develops. It certainly seems like it has a lot of promise. You mentioned in your article a lot about how AI can be used to improve screening for patients for certain types of conditions, and that certainly seems like an obvious win. But as I was reading the article, I couldn't help but worry that, at least in the short term, these tools could translate into more work for busy neurologists and more demand for access, which is, you know, already, you know, big problems in our field. How can tools like these, such as, like, for instance, the AI fundoscopic screening for vascular cognitive risk factors help without adding to these existing burdens? Dr Hadar: It's a very good point. And I think it's one of the central points of why we wanted to write the article is that these AI in medicine, it's, it's a tool like any other. And just like when the electronic medical record came into being, a lot of folks thought that this was going to save a lot of time. And you know, some people would say that it actually worsened things in a way. And when you use these diagnostic screening tools, there is an improvement in efficiency, there is an improvement in patient care. But it's important that doctors, patients advocate for this to be value-based and not revenue-based, necessarily. And it doesn't mean that suddenly the appointments are shorter, that now physicians have to see twice as many patients and then patients just have less of a relationship with their provider. So, it's important to just be able to integrate these tools in an appropriate way in which the provider and the patient both benefit. Dr Grouse: You mentioned earlier about the digital twin. Certainly, in your article you mentioned, you know, that idea along with the idea of the potential of development of virtual chatbot visits or in-person visits with a robot neurologist. And I read all this with equal parts, I think excitement, but horror and and fear. Can you tell us more about what these concepts are, and how far are we from seeing technology like this in our clinics, and maybe even, what are the risks we need to be thinking about with these? Dr Hadar: Yeah. So, I mean, I definitely think that we will see implementation of some of these tools in our lifetime. I'm not sure if we're going to have a full walking, talking robot doing some of the clinical visits. But I do think that, especially as we start doing a lot more virtual visits, it is very easy to imagine that there will be some sort of video AI doctor that can serve as, effectively, a digital twin of me or someone else, that can see patients and diagnose them. The idea behind the digital twin is that it's kind of like an AI version of yourself. So, while you only see one patient, an AI twin can go and see two or three other patients. They could also, if the patients send you messages, can respond to those messages in a way that you would, based on your training and that sort of thing. So, it allows for the ability to be in multiple places at once. One of the risks of this is, I guess, overreliance on the technology, where if you just say, we're just going to have a chatbot do everything for us and then not look at the results, you really run the risk of the chatbot just recommending really bad things. And there is training to be had. Maybe in fifty years the chatbot will be at the same level as a physician, but there's still a lot of room for improvement. I personally, I think that my suspicion as to where things will go are for very simple visits in the future and in our lifetime. If someone is having a cold or something like that and it goes to their primary care physician, a chatbot or something like that may be of really beneficial use. And it'll help segment out the different groups of simple diagnosis, simple treatments can be seen by these robots, these AI, these machine learning tools; and some of the more complex ones, at least for the early implementation of this will be seen by more specialized providers like neurologists and subspecialist neurologists too. Dr Grouse: That certainly seems reasonable, and it does seem that the more simple algorithmic things are always where these technologies will start, but it'll be interesting to see where things can go with more complex areas. Now I wanted to switch gears a little bit in the article- and I thought this was really important because I see it as being certainly one of the bigger drawbacks of AI, is that despite the many benefits of artificial intelligence, AI can unfortunately perpetuate systemic bias. And I'm wondering if you could tell us a little bit more about how this happened? Dr Hadar: I know I'm beating a dead horse on this, but AI is a tool like any other. And the problem with it is that what you put in is very similar to what you get out. And there's this idea in computer science of “garbage in, garbage out”. If you include a lot of data that has a lot of systemic biases already in the data, you're going to get results that perpetuate these things. So, for instance, if in dermatologic practices, if you just had a data set that included people of one skin color or one race and you attempted to train a model that would be able to detect skin cancer lesions, that model may not be easily applicable to people of other races, other ethnicities, other skin colors. And that can be very damaging for care. And it can actually really, really hurt the treatments for a lot of the patients. So that is one of the, kind of, main components of the systemic biases in AI. The way we mitigate them is by being aware of it and actually implementing, I guess, really hard stops on a lot of these tools before they get into practice. Being sure, did your data set include this breakdown of sex and gender, of race and ethnicity? So that the stuff you have in the AI tool is not just a very narrow, focused application, but can be generalized to a large population, not just of one community, one ethnic group, racial group, one country, but can really be generalized throughout the world for many patients. Dr Grouse: The first step is being aware of it, and hopefully these models will be built thoughtfully to help mitigate this as much as possible. I wanted to ask as well, another concern about AI is the safety of private data. And I'm wondering, as we're starting to do things like use ambient documentation, AI scribe, and other types of technologies like this, what can we tell our patients who are concerned about the safety of their personal data collected via these programs, particularly when they're being stored or used with outside companies that aren't even in our own electronic medical records system? Dr Hadar: Yeah, it's a very good question, and I think it's one of the major limitations of the current implementation of AI into clinical practice, because we still don't really have great standards---medical standards, at least---for storing this data, how to analyze this data. And my suspicion is that at some point in the future, we're going to need to have a HIPAA compliance that's going to be updated for the 21st century, that will incorporate the appropriate use of these tools, the appropriate use of these data storage, of data storage beyond just PHI. Because there's a lot more that goes into it. I would say that the important thing for how to implement this, and for patients to be aware of, is being very clear and very open with informed consent. If you're using a company that isn't really transparent about their data security and their data sharing practices, that needs to be clearly stated to the patient. If their data is going to be shared with other people, reanalyzed in a different way, many patients will potentially consider not participating in an AI implementation in clinic. And I think the other key thing is that this should be, at least initially, an opt-in approach as opposed to an opt-out approach. So patients really have- can really decide and have an informed opinion about whether or not they want to participate in the AI implementation in medicine. Dr Grouse: Well, thank you so much for explaining that. And it does certainly sound like there's a lot of development that's going to happen in that space as we are learning more about this and the use of it becomes more prevalent. Now, I also wanted to ask, another good point that you made in your article---and I don't think comes up enough in this area, but likely will as we're using it more---AI has a cost, and some of that cost is just the high amount of data and computational processing needed to use it, as well as the effects on the environment from all this energy usage. Given this drawback of AI, how can we think about potential costs versus the benefits, the more widespread use of this technology? Or how should we be thinking about it? Dr Hadar: It's part of a balance of the costs and benefits, effectively, is that AI---and just to kind of name some of them, when you have these larger data centers that are storing all this data, it requires a lot of energy consumption. It requires actually a lot of water to cool these things because they get really hot. So, these are some of the key environmental factors. And at this point, it's not as extreme as it could be, but you can imagine, as the world transitions towards an AI future, these data centers will become huge, massive, require a lot of energy. And as long as we still use a lot of nonrenewable resources to power our world, our civilization, I think this is going to be very difficult. It's going to allow for more carbon in the atmosphere, potentially more climate change. So, being very clear about using sustainable practices for AI usage, whether it be having data centers specifically use renewable resources, have clear water management guidelines, that sort of thing will allow for AI to grow, but in a sustainable way that doesn't damage our planet. In terms of the financial costs… so, AI is not free. However, on a given computer, if you want to run some basic AI analysis, you can definitely do it on any laptop you have and sometimes even on your phone. But for some of these larger models, kind of the ones that we're talking about in the medical field, it really requires a lot of computational power. And this stuff can be very expensive and can get very expensive very quickly, as anyone who's used any of these web service providers can attest to. So, it's very important to be clear-eyed about problems with implementation because some of these costs can be very prohibitive. You can run thousands and you can quickly rack up a lot of money for some very basic analysis if you want to do it in a very rapid way, in a very effective way. Dr Grouse: That's a great overview. You know, something that I think we're all going to be having to think about a lot more as we're incorporating these technologies. So, important conversations I hope we're all having, and in our institutions as we're making these decisions. I wanted to ask, certainly, as some of our listeners who may be still in the training process are hearing you talk about this and are really excited about AI and implementation of technology in medicine, what would you recommend to people who want to pursue a career in this area as you have done? Dr Hadar: So, I think one of the important things for trainees to understand are, there are different ways that they can incorporate AI into their lives going forward as they become more seasoned doctors. There are clinical ways, there are research ways, there are educational ways. A lot of the research ways, I'm one of the researchers, you can definitely incorporate AI. You can learn online. You can learn through books about how to use machine learning tools to do your analysis, and it can be very helpful. But I think one of the things that is lacking is a clinician who can traverse both the AI and patient care fields and be able to introduce AI in a very effective way that really provides value to the patients and improves the care of patients. So that means if a hospital system that a trainee is eventually part of wants to implement ambient technology, it's important for physicians to understand the risks, the benefits, how they may need to adapt to this. And to really advocate and say, just because we have this ambient technology doesn't mean now we see fifty different patients, and then you're stuck with the same issue of a worse patient-provider relationship. One of the reasons I got into medicine was to have that patient-provider interaction to not only be kind of a cog in the hospital machine, but to really take on a role as a healer and a physician. And one of the benefits of these AI tools is that in putting the machine in medicine, you can also put the humanity back in medicine at times. And I think that's a key component that trainees need to take to heart. Dr Grouse: I really appreciate you going into that, and sounds like there's certainly need. Hoping some of our listeners today will consider careers in pursuing AI and other types of technologies in medicine. I really appreciate you coming to talk with us today. I think this is just such a fascinating topic and an area that everybody's really excited about, and hoping that we'll be seeing more of this in our lives and hopefully improving our clinical practice. Thank you so much for talking to us about your article on AI in clinical neurology. It was a fascinating topic and I learned a lot. Dr Hadar: Thank you very much. I really appreciate the conversation, and I hope that trainees, physicians, and others will gain a lot and really help our patients through this. Dr Grouse: So again, today I've been interviewing Dr Peter Hadar about his article on clinical applications of artificial intelligence in neurology practice, which he wrote with Dr Lydia Moura. This article appears in the most recent issue of Continuum on neuro-ophthalmology. Be sure to check out Continuum Audio episodes from this and other issues. And thank you to our listeners for joining today. Dr Monteith: This is Dr Teshamae Monteith, Associate Editor of Continuum Audio. If you've enjoyed this episode, you'll love the journal, which is full of in-depth and clinically relevant information important for neurology practitioners. Use the link in the episode notes to learn more and subscribe. Thank you for listening to Continuum Audio.

Neuro-ophthalmic deficits significantly impair quality of life by limiting participation in employment, educational, and recreational activities. Low-vision occupational therapy can improve cognition and mental health by helping patients adjust to visual disturbances. In this episode, Katie Grouse, MD, FAAN, speaks with Sachin Kedar, MD, FAAN, author of the article “Symptomatic Treatment of Neuro-ophthalmic Visual Disturbances” in the Continuum® April 2025 Neuro-ophthalmology issue. Dr. Grouse is a Continuum® Audio interviewer and a clinical assistant professor at the University of California San Francisco in San Francisco, California. Dr. Kedar is the Cyrus H Stoner professor of ophthalmology and a professor of neurology at Emory University School of Medicine in Atlanta, Georgia. Additional Resources Read the article: Symptomatic Treatment of Neuro-ophthalmic Visual Disturbances Subscribe to Continuum®: shop.lww.com/Continuum Earn CME (available only to AAN members): continpub.com/AudioCME Continuum® Aloud (verbatim audio-book style recordings of articles available only to Continuum® subscribers): continpub.com/Aloud More about the American Academy of Neurology: aan.com Social Media facebook.com/continuumcme @ContinuumAAN Guest: @AIIMS1992 Full episode transcript available here Dr Jones: This is Dr Lyell Jones, Editor-in-Chief of Continuum. Thank you for listening to Continuum Audio. Be sure to visit the links in the episode notes for information about earning CME, subscribing to the journal, and exclusive access to interviews not featured on the podcast. Dr Grouse: This is Dr Katie Grouse. Today I'm interviewing Dr Sachin Kedar about his article on symptomatic treatment of neuro-ophthalmic visual disturbances, which appears in the April 2025 Continuum issue on neuro-ophthalmology. Welcome to the podcast, and please introduce yourself to our audience. Dr Kedar: Thank you, Katie. This is Sachin Kedar. I'm a neuro-ophthalmologist at Emory University, and I've been doing this for more than fifteen years now. I trained in both neurology and ophthalmology, with a fellowship in neuro-ophthalmology in between. It's a pleasure to be here. Dr Grouse: Well, we are so happy to have you, and I'm just so excited to be discussing this article with you, which I found to be a real treasure trove of useful clinical information on a topic that many find isn't covered enough in their neurologic training. I strongly recommend all of our listeners who work with patients with visual disturbances to check this out. I wanted to start by asking you what you hope will be the main takeaway from this article for our listeners? Dr Kedar: The most important takeaway from this article is, just keep vision on your radar when you are evaluating your patients with neurological disorders. Have a list of a few symptoms, do a basic screening vision, and ask patients about how their vision is impacting the quality of life. Things like activities of daily living, hobbies, whether they can cook, dress, ambulate, drive, read, interact with others. It is very important for us to do so because vision can be impacted by a lot of neurological diseases. Dr Grouse: What in the article do you think would come as the biggest surprise to our listeners? Dr Kedar: The fact that impairment of vision can magnify and amplify neurological deficits in a lot of what we think of as core neurological disorders should come as a surprise to most of the audience. Dr Grouse: On that note, I think it's probably helpful if you could remind us about the types of visual disturbances we should be thinking about and screening for in our patients? Dr Kedar: Patients who have neurological diseases can have a whole host of visual deficits. The simplest ones are deficits of central vision. They can have problems with their visual field. They can have abnormalities of color vision or even contrast sensitivity. A lot of our patients also complain of light sensitivity, eyes feeling tired when they're doing their usual stuff. Some of our patients can have double vision, they can have shaky vision, which leads to their sense of imbalance and maybe a fall risk to them. Dr Grouse: It's really helpful to think about all the different aspects in which vision can be affected, not just sort of the classic loss of vision. Now, your article also serves as a really important reminder, which you alluded to earlier, about how impactful visual disturbances can be on daily activities. Could you elaborate a little further on this, and particularly the various domains that can be affected when there are visual disturbances present? Dr Kedar: So, when I look at how visual disturbances affect quality of life, I look at two broad categories. One is activities of basic daily living. These would be things like, are you able to cook? Are you able to ambulate not just in your home, but in your neighborhood? Are you able to drive to your doctor's appointment or to visit with your family? Are you able to dress yourself appropriately? Are you able to visualize the clothing and choose them appropriately? And then the second category is recreational activities. Are you able to read? Are you able to watch television? Are you able to visit the theatre? Are you able to travel? Are you able to participate in group activities, be it with your family or be it with your social group? It is very important for us to ask our patients if they have problems doing any of this because it really can adversely impact the quality of life. Dr Grouse: I think, certainly with all the things we try to get through talking with our patients, this may not be something that we do spend a lot of time on. So, I think it's it is a good reminder that when we can, being able to ask about these are going to be really important and help us hit on a lot of other things we may not even realize or know to ask about. Now, I was really struck when I was reading your article by the meta-analysis that you had quoted that had showed 47% higher risk of developing dementia among the visually impaired compared to those without visual impairments. Should we be doing more in-depth visual testing on all of our patients with cognitive symptoms? Dr Kedar: This is actually the most interesting part of this article, and kind of hones in on the importance of vision in neurological disorders. Now I want to clarify that patients with visual disorders, it's not a causative influence on dementia, but if you have a patient with an underlying cognitive disorder, any kind of visual disturbance will significantly make it worse. And this has been shown in several studies, both in the neurologic and in the ophthalmological literature. So, I quoted one of the big meta-analysis over there, but studies have clearly shown that if you have these patients and treat them for their visual deficits, their cognitive indices can actually significantly improve. To answer your question, I would say a neurologist should include basic vision screening as part of every single evaluation. Now, I know it's a hard thing in, you know, these days when we are literally running on the hamster wheel, but I can assure you that it won't take you more than 2 to 3 minutes of your time to do this basic screening; in fact, you can have one of your assistants included as part of the vital signs assessment. What are these basic screening tools? Measure the visual acuity for both near and distance. Check and see if their visual field’s off with the confrontation. Look at their eye movements. Are they able to move their eyes in all directions? Are the eyes stable when they're trying to fixate on a particular point? I think if you can do these basic things, you will have achieved quite a bit. Dr Grouse: That's really helpful, and thanks for going through some of the standard, or really, you know, solid basic foundation of visual testing we should be thinking about doing. I wanted to move on to some more details about the visual disturbances. You made an excellent point that there are many types of primary ophthalmologic conditions that can cause visual disturbances that we should keep in mind. So maybe not things that we think about a lot on a day-to-day basis, but, you know, are still there and very common. What are some of the most common ones, and when should we be referring them to see an ophthalmologist? Dr Kedar: So, it depends on the age group of your patient population. Now, the majority of us are adult neurologists, and so the kinds of ophthalmic conditions that we see in this population is going to be different from the pediatric age group. So in the adult population, we might see patients with uncorrected refractive error, presbyopia, patients who have cataracts creep on them, they may have glaucoma, they may have macular degeneration, and these tend to have a slightly higher incidence in the older age group. Now for those of us who are taking care of the younger population, uncorrected refractive errors, strabismus and amblyopia tend to be fairly common causes of visual deprivation in this age group. What I would encourage all of our neurologists is, make sure that your patients get a basic eye examination at least once a year. Just like you want them to go to their primary care and get an annual maintenance visit, everybody should go to the ophthalmologist or the optometrist and get a basic examination. And, if you're resourceful enough, have your patients bring a copy of that assessment. Whether it is normal or there's some abnormality, it is going to help you in the management. Dr Grouse: Absolutely. I think that's a great piece of advice, to think of it almost, like, them seeing their primary care doctor, which of course we offer encourage our patients to do, thinking of this as another very important piece of standard primary care. If a patient comes to you reporting difficulty reading due to possible visual disturbances, I'm curious, can you walk us through how you would approach this evaluation? Dr Kedar: It is not a very common presenting complaint of our patients, even in the neuro-ophthalmology clinic. It's a very rare patient that I see who comes and says, I cannot read or, I have difficulty reading. Most of the patients will come saying, oh, I cannot see. And then you have to dig in to find out, what does that actually mean? What can you not see? Is it a problem in your driving? Is it a problem in your reading? Or is it a problem that occurs at all times? Now you asked me, how do you approach this evaluation? One of the things that all of us, whether we are neurologists, ophthalmologists, or neuro-ophthalmologists, forget to do is to actually have the patient read a paragraph, a sentence, when they are in clinic. And that will give you a lot of ideas about what might actually be going wrong with the patient. Now, as far as how do I approach this evaluation, I will do a basic screening examination to make sure that their visual acuity is good for both distance and near. A lot of us tend to do either distance or near and we will miss the other parameter. You want to do a basic confrontation visual field to make sure that they do not have any subtle deficits that's impacting their ability to read. Examine the eye movements, do a fundoscopic examination. Now, once you've done this basic screening, as a neurologist, you already have some idea of whether your patient has a lesion along the visual pathways. If you suspect that this is a problem with, say, the visual pathways, ask your ophthalmology colleague to do a formal visual field assessment, and that'll pick up subtle deficits of central visual field. And lastly, don't forget higher visual function testing or cortical visual function testing. So basically, you're looking for neglect, phenomenon, or simultanagnosia, all of which tends to have an impact on reading. So, in the manuscript I have a schema of how you can approach a patient with reading difficulties, and in that ischemia you will see categories of where things can go wrong during the process of reading. And if you can approach your patient systematically through one of those domains, there's a fairly good chance that you'll be able to pick up a problem. Dr Grouse: Going a little further on to when you do identify problems with loss of central or peripheral vision, what are some strategies for symptomatic management of these types of visual disturbances? Dr Kedar: As a neurologist, if you pick up a problem with the vision, you have to send this patient to an eye care provider. The vast majority of people who have visual disturbances, it’s from an eye disease. You know, as I alluded to earlier, it can be something as simple as uncorrected refractive error, and that can be fixed easily. A lot of patients in our older age group will have dry eye syndrome, which means they are unable to adequately lubricate the surface of the eye, and as a result, it degrades the quality of their vision. So, they tend to get intermittent episodes of blurred vision, or they tend to get glare. They tend to get various forms of optical aberration. Patients can have cataracts, patients can have glaucoma or macular degeneration. And in all of those instances, the goal is to treat the underlying disease, optimize the vision, and then see what the residual deficit is. By and large, if a patient has a problem with the central vision, then magnification will help them for activities that they perform at near; say, reading. Now for patients with peripheral vision problem, it's a different entity altogether. Again, once you've identified what the underlying cause is, your first goal is to treat it. So, for example, if your patient has glaucoma, which is affecting peripheral vision, you're going to treat glaucoma to make sure that the visual field does not progress. Now a lot of what happens after that is rehabilitation, and that is always geared towards the specific activities that are affected. Is it reading? Is it ambulating? Is it watching television? Is it driving? And then you can advise as a neurologist, you can advise your occupational therapist or low vision specialist and say, hey, my patient is not able to do this particular activity. Can we help them? Dr Grouse: Moving on from that, I wanted to also hit on your approach when patients have disorders of ocular motility. What are some things you can do for symptomatic management of that? Dr Kedar: So, patients with ocular motility can have two separate symptoms. Two, you know, two disabling symptoms, as they would call it. One is double vision and the other is oscillopsia, or the feeling or the visualization of the environment moving in response to your eyes not being able to stay still. Typically, you would see this in nystagmus. Now, let's start with diplopia. Diplopia is a fairly common presenting complaint for neurologists, ophthalmologists, and the neuro-ophthalmologist. The first aspect in the management of diplopia is to differentiate between monocular diplopia and binocular diplopia. Now, monocular diplopia is when the double vision persists even after covering one eye. And that is never a neurological issue. It's almost always an ophthalmic problem, which means the patient will then have to be assessed by an eye care provider to identify what's causing it. And again, refractive error, cataracts, opacities, they can do it. Now, if the patient is able to see single vision by covering one eye at a time, that's binocular diplopia. Now, in patients with binocular diplopia in the very early stages of the disease, the standard treatment regimen is just monocular occlusion. Cover one eye, the diplopia goes away, and then give it time to improve on its own. So, this is what we would typically do in a patient with, say, acute sixth nerve palsy or fourth nerve palsy or third nerve palsy, maybe expect spontaneous improvement in a few months. Now if the double vision does not improve and persists long term, then the neuro-ophthalmologist or the ophthalmologist will monitor the amount of deviation to see if it fluctuates or if it stays the same. So, what are the treatment options that we have in a patient who absolutely refuses any intervention or is not a candidate for any intervention? Monocular occlusion still remains the viable option. Now, patients who have stable ocular deviation can benefit from using prisms in their glasses, or they can be sent to a surgeon to have a strabismus surgery that can realign their eyes. So, again, a broad answer, but there are options available that we can use. Dr Grouse: Thank you for that overview. I think that's just really helpful to keep in mind as we're working with these patients and thinking about what their options are. And then finally, I wanted to touch on patients with higher-order vision processing and attention difficulties. What are some strategies for them? Dr Kedar: These are frankly the most difficult patients that I get to manage in my clinic, simply because there is no effective therapies for managing them. In fact, I think neurologists are far better at this than ophthalmologists or even neuro-ophthalmologists. In patients with attentional disorders, everything boils down to the underlying cause, whether you can treat it or whether it is a slowly progressive, you know, condition, such as from neurodegenerative diseases. And that tailors our goals towards therapy. The primary goal is for safety. A lot of these patients who have visual disturbances from vision processing or attention, they are at accident and fall risk. They have problems with social interactions. And, importantly, there is a gap of understanding of what's going on, not just from their side but also from the family’s side. So, I tend to approach these patients from a safety perspective and social interaction perspective. Now, I have a table listed in the manuscript which will go into details of what the specific things are. But in a nutshell, if your patient has neglect in a specific part of the visual field, they have accident risk on that side. Simple things like walking through a doorway, they can hurt their shoulders or their knees when they bang into the wall on that side because they are unable to judge what's on the other side. Another example would be a patient who has simultanagnosia or a downgaze policy, such as from progressive super nuclear policy. They are unable to look down fast enough, or they are simply unable to look down and appreciate things that are on the floor, and so they can trip and fall. Walking downstairs is also not a huge risk because they are unable to judge distances as they walk down. A lot of what we see in these patients are things that we have to advise occupational therapists and help them improve these safety parameters at home. Another thing that we often forget is patients can inadvertently cause a social incident when they tend to ignore people on their affected side. So, if there is a family gathering, they tend to consistently ignore a group of people who are sitting on the affected side as opposed to the other side. And I've had more than a few patients who've come and said that, I may have offended some of my friends and family. In those instances, it's always helpful when they are in clinic to demonstrate to the family how this can be awkward and how this can be mitigated. So, having everybody sit on one side is a useful strategy. Advise your family and friends before a gathering that, hey, this may happen. And it is not because it is deliberate, but it's because of the medical condition. And that goes a lot, you know, further in helping our patients come out of social isolation because they are also afraid of offending people, you know. And they can also participate socially, and it can overall improve their quality of life. Dr Grouse: That's a really helpful tip, and something I'll keep in mind with my patients with neglect and visual field cuts. Thank you so much for coming to talk with us today. Your article has been so helpful, and I urge everybody listening today to take a look. Dr Kedar: Thank you, Katie. It was wonderful talking to you. Dr Grouse: I've been interviewing Dr Sachin Kedar about his article on symptomatic treatment of neuro-ophthalmic visual disturbances, which appears in the most recent issue of Continuum on neuro-ophthalmology. Be sure to check out Continuum Audio episodes from this and other issues. And thank you to our listeners for joining today. Dr Monteith: This is Dr Teshamae Monteith, Associate Editor of Continuum Audio. If you've enjoyed this episode, you'll love the journal, which is full of in-depth and clinically relevant information important for neurology practitioners. Use the link in the episode notes to learn more and subscribe. AAN members, you can get CME for listening to this interview by completing the evaluation at continpub.com/audioCME. Thank you for listening to Continuum Audio.

In this discussion, Dr. Gregory Van Stavern, a neuro-ophthalmologist and professor at Washington University, dives into the complex world of ocular motor disorders. He highlights the importance of clinical evaluations over imaging in diagnosis. The conversation reveals how specific eye movement tests can differentiate between conditions like Parkinson's disease and progressive supranuclear palsy. Dr. Van Stavern also explores automated analysis tools and the need for better neuro-ophthalmology training for medical students, aiming to inspire the next generation in this specialty.

Double vision is a symptom often experienced by patients with neurologic disease. An organized systematic approach to evaluating patients with diplopia needs a foundational understanding of the neuroanatomy and examination of eye movements and ocular alignment. In this episode, Teshamae Monteith, MD, FAAN, speaks with Devin Mackay, MD, FAAN, author of the article “Approach to Diplopia” in the Continuum® April 2025 Neuro-ophthalmology issue. Dr. Monteith is the associate editor of Continuum® Audio and an associate professor of clinical neurology at the University of Miami Miller School of Medicine in Miami, Florida. Dr. Mackay is an associate professor of neurology, ophthalmology, and clinical neurosurgery at Indiana University School of Medicine in Indianapolis, Indiana. Additional Resources Read the article: Approach to Diplopia Subscribe to Continuum®: shop.lww.com/Continuum Earn CME (available only to AAN members): continpub.com/AudioCME Continuum® Aloud (verbatim audio-book style recordings of articles available only to Continuum® subscribers): continpub.com/Aloud More about the American Academy of Neurology: aan.com Social Media facebook.com/continuumcme @ContinuumAAN Host: @headacheMD Full episode transcript available here Dr Jones: This is Dr Lyell Jones, Editor-in-Chief of Continuum. Thank you for listening to Continuum Audio. Be sure to visit the links in the episode notes for information about earning CME, subscribing to the journal, and exclusive access to interviews not featured on the podcast. Dr Monteith: This is Dr Teshamae Monteith. Today I'm interviewing Dr Devin Mackay about his article on approach to diplopia, which appears in the April 2025 Continuum issue on neuro-ophthalmology. Welcome to the podcast. How are you? Dr Mackay: Thank you. It's great to be here. Dr Monteith: Congratulations on your article. Dr Mackay: Thank you. I appreciate that. Dr Monteith: Why don't you start off with introducing yourself to our audience? Dr Mackay: So, yeah, my name is Devin Mackay. I'm a neuro-ophthalmologist at Indiana University. I did my residency at what was used to be known as the Partners Healthcare Program in Boston, and I did a fellowship in neuro-ophthalmology in Atlanta. And I've been in practice now for about ten years. Dr Monteith: Oh, wow. Okay. Tell us a little bit about your goals when you were writing the chapter. Dr Mackay: So, my goal with the approach to double vision was really to demystify double vision. I think double vision is something that as trainees, and even as faculty members and practicing neurologists, we really get intimidated by, I think. And it really helps to have a way to approach it that demystifies it and allows us to localize, just like we do with so many other problems in neurology. Dr Monteith: I love that, demystification. So why don't you tell us what got you interested in neuro-ophthalmology? Dr Mackay: Yeah, so neuro-ophthalmology I stumbled on during a rotation during residency. We rotated in different subspecialties of neurology and I did neuro-ophthalmology, and I was just amazed by the exam and how intricate it was, the value of neuroanatomy and localization, the ability to take a complicated problem and kind of approach it as a diagnostic specialist and really unravel the layers of it to make it better. To, you know, figure out what the problem is and make it better. Dr Monteith: Okay, so you had a calling, clearly. Dr Mackay: I sure did. Dr Monteith: You talked about latest developments in neuro-ophthalmology as it relates to diplopia. Why don't you share that with our listeners? Dr Mackay: Yeah. So, you know, double vision is something that's really been around since the beginning of time, essentially. So that part hasn't really changed a lot, but there are some changes that have happened in how we approach double vision. Probably one of the bigger ones has been, we used to teach that with a, you know, patient over the age of fifty with vascular risk factors who had a cranial nerve palsy of cranial nerves 3, 4, or 6, we used to automatically assume that was a microvascular palsy and we just wouldn't do any more testing and we'd just, you know, wait to see how they did. And it turns out we're missing some patients who have significant pathologies, sometimes, with that approach. And so, we've really shifted our teaching with that to emphasize that it's a lot easier to get an MRI, for example, than it ever has been. And it can be important to make sure we're not missing important pathology in patients, even if they have vascular risk factors over the age of fifty and they just have a cranial nerve 3, 4, or 6 palsy. So that's been one change. Dr Monteith: Interesting. And why don't you tell us a little bit about the essential points that you want to get across in the article? Dr Mackay: Yeah. So, I think one is to have a systematic approach to double vision. And a lot of that really revolves around localization. And it even begins with the history that we take from the patients. There's lots of interesting things we can ask about double vision from the patient. For example, the most important thing you can ever ask someone with double vision is, does it go away when you cover either eye? And that really helps us figure out the first question for us as neurologists, which is, is it neurologic or non-neurologic? If it's still there when covering one eye, then it is not neurologic and that's usually a problem for an ophthalmologist to sort out. So that's really number one. And then if it is binocular double vision, then we get into details about, is it horizontal or vertical misalignment? Is it- what makes it better and worse? Is there an associated ptosis or other symptoms? And based on all of that, we can really localize the abnormality with the double vision and get into details about further testing if needed, and so forth. I also love that that approach really reduces our need to rely on things like neuroimaging sometimes when we may not need it, or on other tests. So, I think it really helps us be more efficient and really take better care of patients. Dr Monteith: So definitely that cover/uncover test, top thing there. Your approach- and you mentioned, are you really getting that history, and are there any other kind of key factors when you're approaching diplopia before getting into some of the details? Dr Mackay: Yeah, that's a good question. I think also having some basics of how to examine the patient, because double vision is such a challenging thing. A lot of us aren't as familiar with the exam toolkit, so to speak, of what you would do with a patient with double vision. And so, I go over in the article a bit about a Maddox rod, which is a handy little tool that I always keep in my pocket of my lab coat. It allows you to assign a red line to one eye and a light to the other eye, and you can see if the eyes line up or not. And you don't need any other special equipment, you just need the light in that Maddox rod. That really helps us understand a lot about the pattern of misalignment, which is really important for evaluating double vision. So, for example, if someone has a right 6th nerve palsy, I'll expect a horizontal misalignment of the eyes that worsens when the patient looks to the right and improves when they look to the left. And especially if it's a partial palsy, it's not always easy to see that just by looking at their eye movements. And having a way to really measure the eye alignment and figure out, is it worse or better in certain directions, is really essential to localization, I think, in a lot of cases. Dr Monteith: You caught me. I skipped over that Maddox rod part, even though you spent a lot of time talking about Maddox rods. Kind of skipped over it. So, you're saying that I need one. Dr Mackay: Everyone needs one. I've converted some of our residents here to carry one with them. And yeah, I realize it's a daunting tool at first, but when you have a patient with double vision and their eye movements look normal, I feel like a lot of neurologists are- kind of, their hands seem like they're tied and they’re like, oh, I don't know, I don't know what to do at this point. And if you can get some more details with a simple object like that, it can really change things. Dr Monteith: So, we’ve got to talk to the AAN store and make sure that they have enough of these, because now there's going to be lots of… Dr Mackay: We're going to sell out on Amazon today now because of this podcast. Dr Monteith: Cyber Monday. So, let's talk about the H pattern. And I didn't know it had the- well, yeah, I guess the official name is “H pattern.” In medical school, I mean, that's what I learned. But as a resident and, you know, certainly as an attendee, I see people doing all sorts of things. You're pro-H pattern, but are there other patterns that you also respect? Dr Mackay: It depends on what you're looking for, I think. The reason I like the H pattern is because you get to look at upgaze and downgaze in two different directions. So, you get to look at upgaze and downgaze when looking to the left, and up- and downgaze when looking to the right. And the reason that matters is because vertical movements of the eyes are actually controlled by different eye muscles depending on whether the eye is adducted toward the nose or abducted away from the nose. And so that's why I love the H pattern, is because it allows you to see that. If you just have them look up and down with just a cross pattern, for example, then you really lose that specificity of looking at both the adduction and abduction aspects. So, it's not wrong to do it another way with, like, the cross, for example, but I just think there are some cases where we'll be missing some information, and sometimes that can actually make a difference. Dr Monteith: Well, there you have it. Let's talk a little bit about eliciting diplopia during the neurologic exam. What other things should we be looking out for? Dr Mackay: So, in terms of eliciting diplopia, it really starts with the exam and again, figuring out, are we covering one eye? And figuring out, is this patient still having double vision? It's tricky because sometimes the patients won't even know the answer to that question or they've never done it, they’ve never covered one eye. And so, if that's the case, I really make them do it in the office with me and it's like, okay, well, are we having double vision right now? Well, great, okay, we are, then we're going to figure this out right now. And we cover one eye and say, is it still double? And that way we can really figure out, are we monocular or binocular? That's always step one. And then if we've established that it's binocular diplopia, then that's when we get into the other details that I mentioned before. And then as far as other things to look for, we're always in tune to other things that are going on in terms of symptoms, like ptosis, or if there's bulbar weakness, or some sensory change or motor problem that seems to be associated with it. Obviously, those will give us clues in the localization as well. Dr Monteith: And what about ocular malalignment? Dr Mackay: Yeah. So ocular malalignment, really, the cardinal symptom of that is going to be double vision. And so, if a patient has a misalignment of the eyes and they don't have double vision, then usually that means either we're wrong and they don't have double vision, or they do have double vision and they, you know, haven't said it correctly. Or it could be that the vision is poor in one eye. Sometimes that can happen. Or, some patients were actually born with an eye misalignment and their brain has learned in a way to kind of tune out or not allow the proper development of vision in one eye. And so that's also known as amblyopia, also known as the lazy eye, some people call it. But that finding can also make someone not experience double vision. But otherwise, if someone's had normal vision kind of throughout their life, they'll usually be pretty aware of when they first notice double vision. It'll be an obvious event for them in in most cases. Dr Monteith: And then the Cogan lid twitch? Dr Mackay: Oh yes, the Cogan lid twitch. So, the Cogan lid twitch is a feature of myasthenia gravis. The way you elicit it is, you have the patient look down. I'm not sure there's a standardization for how long; you want to have it long enough that you're resting the levator muscle, which is the muscle that pulls the upper lid open. And so, you rest that by having them look down for… I usually do about ten or fifteen seconds. And then I have them look up to looking straight forward. And you want to pay careful attention to their lid position as their eye settles in that straight-forward position. What will happen with a Cogan's lid twitch is, the lid will overshoot, and then it'll come back down and settle into its, kind of, proper position. And what we think is happening there is, it's almost like a little mini “rest test” in a way, where you're resting that muscle just long enough to allow some of the neurotransmission to recover. You get a normal contraction of the muscle, but it fades very quickly and comes back down. And that's experienced as a twitch. Dr Monteith: So, the patient can feel it. And it's something you can see? Dr Mackay: Yeah, the patient may not feel it as much. It's usually it's going to be something that the clinician can see if they're looking for it. And I would say that's one of the physical exam findings that can be a hallmark of myasthenia gravis, but certainly not the only one. Some others that we often look for are fatigable ptosis with sustained upgaze. You have the patient look up for a prolonged time and you'll see the lid droop down. So that can be one. Ice pack test is very popular nowadays, and it has pretty good sensitivity and specificity for myasthenia. So, you keep an ice pack over the closed eyes for two minutes and you compare the lid position before and after the ice pack test. And in the vast majority of myasthenia patients, if they have ptosis, the ptosis will have resolved, or at least significantly improved, in those patients. And yet one more sign is, if you find the patient's eye with ptosis and you lift open the eye manually, you'll often see that the other eyelid and the other eye will lower down. So, I'm not sure there's a name for that, but that can be a helpful sign as well. Dr Monteith: Since you're going through some of these, kind of, key features of different neurologic disease, why don't you tell us about a few others? Dr Mackay: Yeah, so another I mentioned in the in the article is measurement of levator function, which is really a test of eyelid strength. And so, that can be helpful if we have- someone has ptosis, or we're not sure if they have ptosis and we're trying to evaluate that to see if it's linked to the double vision, because that really changes the differential if ptosis is part of the clinical situation. So, the way that's measured is you have a patient look down as far as they can. And you get out a little ruler---I usually use a millimeter ruler---and I set the zero of the ruler at the upper lid margin when they're looking down. So, I hold the ruler there, and then I ask the patient to look up as far as they can without moving their head. Where the lid position stops of the upper lid is the new point on the ruler. And so, you measure that and see how much that is. And so, a normal patient may have a value somewhere between, I don't know, twelve or thirteen millimeters up to seventeen or eighteen millimeters, probably, in most cases. Especially if there is an asymmetric lid position, if you find that the levator function is symmetric, then it tells you that the muscle is working fine and that the ptosis is not from the muscle. So then the ptosis may be from dehiscence of the lid margin from the muscle. And so, that's a really common cause of ptosis, and that's often age-related or trauma-related. And we can dismiss that as being part of the symptom constellation of double vision. So, it can be really helpful to clarify, is this a muscle problem, which you'd expect with myasthenia or a third nerve palsy, or is this a mechanical problem with the lid, which is non-neurologic and really should be dismissed? So that can be a really helpful exam tool. Dr Monteith: So, you're just now getting into a little localization. So why don't we kind of start from the most proximal pistol with localization. Give us a little bit of tips. I know they just got to read your article, but give us a few tips. Dr Mackay: So, in terms of most proximal causes, there are supranuclear causes of ocular misalignment. For example, a skew deviation would qualify as that. Anything that's happening from some deficient input before you get to the cranial nerve nuclei, that we would consider supranuclear. So, we also see that with things like progressive supranuclear policy and certain other conditions. And then there can be lesions of the cranial nerve nuclei themselves. So, cranial nerves 3, 4, and 6 all have nuclei, and if they're lesioned they will cause double vision in specific patterns. And then there's also another subgroup, which is known as intranuclear problems with eye alignment. And so, the most common of that is going to be intranuclear ophthalmoplegia. And so that's very common in patients with demyelinating disorders, or it can also happen with strokes and tumors and other causes. And then there's infranuclear problems, which are from the cranial nerve nuclei out, and so those would be the cranial nerves themselves. So that's where your microvascular palsies, any tumor pressing on the nerve in those locations can cause palsies like that, any inflammatory disorder along that course. Then as we get more distal, we get into the orbit, we have the neuromuscular junction---so, the connection between the nerve and the muscle. And of course, that's our myasthenia gravis. And there are rare causes, things like botulinum and tick borne illnesses and certain other things that are more rare. And then, of course, we get to the muscle itself, and there can be different muscular dystrophies, different things like myositis or inflammatory disorders of the orbit or even physical trauma. So, if a patient, you know, had a trauma in trapping an extraocular muscle, that can be a localization. So really, anywhere along that pathway you can have double vision. So, I love to approach it from that perspective to help narrow down the diagnostic possibilities. Dr Monteith: Okay, just like everything? Dr Mackay: Just like all of the rest of the neurology. See, it's not that scary. Dr Monteith: You know, and so, yeah. And then you do a lot more than, you know, a few cranial nerves, right? Dr Mackay: Right. That's right. There's a lot more to double vision than that. I think as neurologists, we get lost if it's not a cranial nerve palsy, we're like, oh, I don't know what this is. And if it's not myasthenia, not a cranial nerve palsy. But it's worth also considering that there are ophthalmologic causes of someone having double vision that we often don't consider. So maybe someone who was born with strabismus, or maybe they have a little bit of a tendency toward an eye misalignment that their brain compensates, for and then it decompensates someday and that now they have a little bit of double vision intermittently, so that those can be causes to consider as well. Dr Monteith: Yeah, well, we'll just have to, you know, request those records from forty years ago. No problem. Dr Mackay: That's right. Dr Monteith: Why don't you also give us a little bit of tip when we're on the wards and we want to teach either a medical student or a resident, or if it's a resident listening, may want to teach a junior resident and seem like a star when approaching a patient with diplopia. Give us some teaching pearls. Dr Mackay: Yeah. So, I would love people teaching more about this at the bedside. I'd say probably the first thing to do would be to equip yourself by recognizing what some of the pertinent questions are to ask someone with double vision. Those things would include, is the double vision worse when looking in a certain direction? Does the double vision go away or not when you cover one eye? What happens when you tilt your head one direction or the other? Is it intermittent or constant? What makes it better? What makes it worse? Those kinds of things can really help us narrow down the possibilities. And then the other thing would be to equip yourself with some tools for examining. And it doesn't have to be physical tools. These can actually be things like, you mentioned the cross-cover test or cover/uncover test. That's described in the article. And I think knowing how to do that properly, knowing how to examine the eye movements properly and how to check for subtle things like a subtle intranuclear ophthalmoplegia, which is also mentioned in the article, being familiar with those things can be a really useful exercise in allowing you to teach others later on. Dr Monteith: Cool. Why don't you tell us about some of the things you're most excited about in the field? Dr Mackay: One of the things about our subspecialty for so long is we really haven't had big data with, you know, big trials and all these things that all the stroke people have. And that's starting to change slowly. There's been, for example, the idiopathic intracranial hypertension treatment trial that was published back in, I think it was 2014. You know, of course we had the optic neuritis treatment trial, back a few decades ago now. Some of the exciting ones coming up, there's going to be a randomized controlled trial looking at different treatments for idiopathic intracranial hypertension that are surgically based. So, for example, comparing venous sinus stenting with optic nerve sheath fenestration. And so, figuring out, is there a best practice for surgical intervention for patients with IIH? So, we're starting to have more trials like that now than I think we've had in the past. And so, it's exciting to get to have an evidence base for some of the things that we recommend and do. Dr Monteith: And what about some of the treatment for diplopia? Like prisms, and where are we with some of that? Dr Mackay: Yeah, great. So, it's a pretty simple concept, but still kind of difficult in practice. I kind of say there are four different ways to treat double vision: you can ignore it, you can patch or cover one eye, you can treat with prisms, and you can treat with eye muscle surgery. And so, those are the main ways other than, of course, treating the underlying disorder if there's a disorder causing double vision. So those are the main ways to treat. In terms of knowing if someone's going to be a candidate for prism therapy, we also have to remember that prisms are really going to be most helpful for when someone's looking straight forward. So, we need to make sure that their double vision is happening when they look straight forward. So, for example, if they're only having double vision looking to the left or to the right, that patient may not benefit from prisms as much as someone who is having double vision when they look straight forward. So that's one thing I look for. And then strabismus surgery is something to be considered if someone is not tolerating prisms and they're not helping and their eye alignment is stable. So, if you think about it, if someone's eye alignment is changing a lot, you're probably not going to want to do surgery for that patient because it's going to keep changing after surgery. And so, if someone's eye alignment is stable for six months or more and they're not getting the benefit they'd like from prisms, then maybe referral to a strabismus surgeon might be something to consider. Dr Monteith: Great. And then, I guess another question is just popping up in my head selfishly. What are your thoughts about patients that get referrals for exercises? Say they have, like, a convergence efficiency or something causing diplopia, maybe after a concussion. Maybe there's not a lot of evidence, but what is your take on exercising? Dr Mackay: Yeah, excellent question. So, there actually is evidence for exercises for convergence insufficiency. So, we know that those do work. Now where exercises are probably not as helpful, or at least not- there isn't an evidence base for them, is really with just about every other kind of eye misalignment in adults. We hear a lot about eye movement therapies for concussion and barely any other acquired misalignment of the eyes as well. And really, the evidence really hasn't shown us that that's helpful; again, with the exception being convergence insufficiency. So, we know that an office-based vision therapy type program for convergence insufficiency does work, but of course it's kind of inconvenient. It can cost money that may or may not be covered by insurance. And so, there are difficulties even with doing that. And so, I often recommend that patients with convergence insufficiency at least try something called pencil push-ups, where they take a pencil at arm's length and they bring it in and exercise that convergence ability. You know, that's a cheap, easy way to try to treat that initially. So yeah, there can be some limited utility for eye muscle exercises in certain conditions. Dr Monteith: My one example. I was- it was fuzzy, but in a different way. So, what do you do for fun? I mean, it sounds like you like to see a lot of eyeballs? Dr Mackay: I do. I like to see a lot of eyeballs. Dr Monteith: When you're not doing these things, what do you do for fun? Dr Mackay: So, people ask me what my hobbies are, and I laugh because my hobby is actually raising children. Dr Monteith: Oh, okay! Dr Mackay: So, my wife and I have eight kids- Dr Monteith: Oh, wow! Dr Mackay: Ages three to thirteen. So, kind of doesn't allow me to have other things right now. I'm sure I'll have more hobbies later on, but no, I really love my kids. And I- they give me plenty to do. There's no shortage of- in fact, they were really, they were really excited about this podcast today. They're so excited that Dad gets to be on a podcast, and so I'm going to have to show this to them later. They're going to be thrilled about it. Dr Monteith: Excellent. Well, thank you so much for being on the podcast. Dr Mackay: Thank you. It's been my pleasure. Dr Monteith: Again, today I've been interviewing Dr Devin Mackay about his article on approach to diplopia, which appears in the most recent issue of Continuum on neuro-ophthalmology. Be sure to check out Continuum Audio episodes from this and other issues. And thank you to our listeners for joining today. Dr Monteith: This is Dr Teshamae Monteith, Associate Editor of Continuum Audio. If you've enjoyed this episode, you'll love the journal, which is full of in-depth and clinically relevant information important for neurology practitioners. Use the link in the episode notes to learn more and subscribe. AAN members, you can get CME for listening to this interview by completing the evaluation at continpub.com/audioCME. Thank you for listening to Continuum Audio.

Dr. Susan Mollan, a consultant neuro-ophthalmologist at University Hospitals Birmingham, shares her expertise on papilledema—optic disc swelling due to increased intracranial pressure. She dives into the critical importance of thorough ocular examinations and offers practical tips for accurate diagnosis. The discussion also explores managing incidental findings in neuroimaging and emphasizes compassionate communication when addressing weight management with patients. Insights from her published article provide valuable guidance for practitioners in the field.

The inflammatory and infectious optic neuropathies are a broad, heterogeneous, and common group of diseases producing visual loss. Although many now-distinct syndromes have been previously combined as “typical or atypical optic neuritis,” recent developments highlight the importance of precision terminology as well as an individualized evaluation and treatment approach. In this episode, Gordon Smith, MD, FAAN speaks with Eric Eggenberger, DO, MS, FAAN, author of the article “Optic Neuritis” in the Continuum® April 2025 Neuro-ophthalmology issue. Dr. Smith is a Continuum® Audio interviewer and a professor and chair of neurology at Kenneth and Dianne Wright Distinguished Chair in Clinical and Translational Research at Virginia Commonwealth University in Richmond, Virginia. Dr. Eggenberger is a professor of ophthalmology, neurology, and neurosurgery at the Mayo Clinic in Jacksonville, Florida. Additional Resources Read the article: Optic Neuritis Subscribe to Continuum®: shop.lww.com/Continuum Earn CME (available only to AAN members): continpub.com/AudioCME Continuum® Aloud (verbatim audio-book style recordings of articles available only to Continuum® subscribers): continpub.com/Aloud More about the American Academy of Neurology: aan.com Social Media facebook.com/continuumcme @ContinuumAAN Host: @gordonsmithMD Full episode transcript available here Dr Jones: This is Dr Lyell Jones, Editor-in-Chief of Continuum. Thank you for listening to Continuum Audio. Be sure to visit the links in the episode notes for information about earning CME, subscribing to the journal, and exclusive access to interviews not featured on the podcast. Dr Smith: This is Dr Gordon Smith. Today I'm interviewing someone who really needs no introduction, Dr Eric Eggenberger, about his article on optic neuritis, which appears in the April 2025 Continuum issue on neuro-ophthalmology. Eric, welcome to the podcast, and maybe you can introduce yourself to our audience. Dr Eggenberger: Thank you. Thanks for having me. So, my name is Eric Eggenberger. I work at Mayo Clinic Florida, and I am involved exclusively in neuro-ophthalmology. Dr Smith: I just had the pleasure, Eric, of talking yesterday with Lindsey De Lott about non-optic neuritis causes of optic neuropathy. And so, I'm going to kind of reference a little bit what I learned yesterday. She was great. I wonder if you might begin by talking a little bit about nomenclature. You talk about the need for use of precise terminology in your article. And yesterday she taught me a lot about the risk of misdiagnosis and other causes of optic neuropathy, and the two seem related. So, I wonder if you can maybe lay the foundation for our conversation by talking about terminology? Dr Eggenberger: I think that's a great point. So, we are in an era now where, instead of lumping all these different diagnoses together, we have learned to split apart some of these clinical entities. And so, I think it's really important that we focus on precise terminology and recognize that all optic neuritis is not the same. And we have very different, distinct clinical pathways for these imaging pathways, treatment pathways, for these different types of optic neuritis, whether that's MS related, whether it's MOG related or aquaporin-4 related. Dr Smith: So, I wonder maybe we can begin by just, you know, giving our listeners wisdom, pearls, and pitfalls about, how do you recognize when someone with a suspected optic neuropathy has optic neuritis versus a noninflammatory optic neuropathy? Dr Eggenberger: So, that's a really important issue because there's a lot of clinical overlap in terms of exam findings. So, for instance, in any optic neuropathy, let's say it's unilateral, you typically are going to see decreases in acuity and field and color, and you're going to see a relative afferent pupillary defect. And then it's really the context that that occurs in that helps us distinguish different disease entities. So, with optic neuritis, typically you're going to have pain. And that's oftentimes going to be in the younger populations compared to some of the other common optic neuropathies we see, like ischemic optic neuropathy, for instance. Dr Smith: Right. So maybe we can talk a little bit about, kind of, your overall diagnostic approach, right? A lot of this is, of course, based on age and context, but young people get ischemic lesions and older people can have inflammatory lesions. So, what's your overall approach to the patient you just described? Let's say it's a forty-eight-year-old woman who comes to the emergency department with subacute unilateral vision loss and there's dyschromatopsia, APD, reduced acuity. And, you know, let's just say a fairly, you know, benign-looking fundoscopic exam. What do you do to evaluate that patient? Dr Eggenberger: In that particular context, I think we're looking at other contextual clues. Is there other vascular risk factors or other things to point you in one direction or the other? One of the important parts you mentioned was the fundus exam. So, we know with ischemic optic neuropathy, 100% of the time with AIOM, you're going to see disc edema. And so, in the context of that story, we want to confirm on our exam an optic neuropathy, and then we can kind of focus on the retrobulbar courses or different types of optic neuropathies. From an exam perspective, in that particular patient we’d be looking to measure the acuity, quantify that. And in the ER, you're not going to be able to do a perfect field, but you'll get some sense of the field and how much field loss there is. And then as you mentioned, the afferent pupillary defect is critical. And we're going to get a little bit of the historical features in terms of pain. With typical retrobulbar optic neuritis, most of those patients are going to experience some pain, and usually it's pain on eye movements. And those would be the clinical things to focus on. Other exposures the patient may or may not have had, any other concomitant conditions, would all help point you in different directions, perhaps, and then we're probably on towards imaging. Dr Smith: Yeah, maybe you can talk a little bit about that? What's the appropriate use of imaging? I mean, presumably the patients, like the one I just threw out there, are pretty much all going to get neuroimaging. What's your approach to that? How do you protocol the study? What should we be looking for? Dr Eggenberger: In our clinic, we would typically be ordering an MRI orbit and brain, and each of those has a specific purpose. The orbit is going to show us the extent of the optic neuropathy. So, we're particularly looking for a longitudinally extensive optic nerve lesion or more than half of the optic nerve involved. And most patients acutely, if it isn't an “itis" situation, we'll see enhancement. And then the MR brain is going to be useful for looking for other evidence of demyelination within the central nervous system. We may at some point get down to doing an MR cord, but I think acutely it's going to be brain and orbit that most of our patients are getting. Dr Smith: Let's say that we did the scan and, sure enough, there's sort of a shorter segment, so less than half the length of the nerve region of enhancement. What's the rest of your diagnostic evaluation look like for that patient? Dr Eggenberger: So, in that particular case, we would look at the remainder of the brain. So, we're looking for other evidence of demyelination and any other contextual clues, systemically that would point you one direction or another. But with a shorter segment involved, one of the more common things we might encounter would be multiple sclerosis-related optic neuritis. Dr Smith: Would you look for aquaporin-4 and MOG in a patient with what appears to be an isolated, uncomplicated short segment optic neuritis? Dr Eggenberger: So, I think it really depends a bit on the context. I would never fault anybody for looking at MOG or an aquaporin-4 in that context because those are really treatment-altering diagnoses, but the yield in this particular case with a short segment involved and depending on the acuity and other features is probably going to be pretty low. Dr Smith: I really liked as an aside- I wasn't going to go there next, but you kind of got me thinking about it, you have a really nice section in your article. Which, all of it's great, but talking about how to manage low titer MOG antibodies. I wonder if you could talk about that because I think that's a lesson, maybe, that is transferable to a lot of other testing that we do. in terms of pre-prior probability and titer and so forth. Dr Eggenberger: Yeah, that's really an important point. So, we've seen this come up a number of times where the MOG antibody is a very good test, but in low titer it has a relatively low positive predictive value, perhaps 50%. In those cases, particularly without a classic clinical context, you have to be extremely alert for some other diagnosis that could mimic what you think is inflammatory demyelinating optic neuritis, but in fact is infectious or some other cause. Dr Smith: Yeah, super, super important and helpful. In terms of aquaporin-4, how does that compare in terms of predictive values, lower titer positive results? Dr Eggenberger: So aquaporin-4, the test has a very high specificity. So, it's quite useful if positive. You have to keep in mind there can be some false negatives, but the test otherwise is quite specific. And that is a diagnosis, you know, we never want to miss. It's a vicious disease. It tends to be a blinding disease, particularly without treatment. Bad things happen when we miss that, and we want to get on that diagnosis early and do pretty aggressive early and prophylactic treatment. Dr Smith: Your article covers not only the common causes of optic neuritis and, you know, MS, isolated optic neuritis, MOGAD NMO, you talk about a bunch of other things. I wonder, in this patient that we've been discussing, in the absence of any other historical information that seems relevant---or maybe you can define what would seem relevant---would you do other evaluation in that individual, other serologic evaluation and so forth, just in terms of diagnosis? Dr Eggenberger: In that particular case, without other red flags, I don't think I would initially. And follow-up is going to give you a lot of this context. So, you'd be on the lookout for other systemic conditions. So, if the patient had some arthropathy, if the patient had any pulmonary disease hints, if there was anything else that could lead you on a broader expedition. But I think in the context of this case, acutely in the ER, I probably wouldn't do a big lab plug for this. I probably would kind of go down the most likely road and start our treatments, and then follow that patient up. Dr Smith: Yeah, I know your article does a really great job, I think, of outlining when do you need to think about some of these less common causes. Well, can we talk about treatment, Eric? Because I want to move on to some other things. But- so, we've got a patient with isolated optic neuritis, nothing else, you know, in terms of the other antibodies we've talked about. What state-of-the-care- or, state-of-the-art treatment for that patient? Dr Eggenberger: So, the acute treatment for these inflammatory, optic neuritis-type cases is very similar Initially. High dose steroids remains kind of the standard. And then, in MS-related optic neuritis, we may or may not see a taper. So many times it's just an acute treatment of three to five days high dose. Whether that's oral or PO, we could institute either depending on the particular case. And then the taper would depend on the potential cause. So, for instance, with these antibody-driven diseases---so with MOG- or particularly with aquaporin-4---if it's a longitudinally extensive region of optic nerve involved, we tend to use a longitudinally extensive taper. And so, we use prednisone in those cases for several months while we're getting everything else set and deciding what the overall course is going to bring. Dr Smith: What about IV versus oral? There must be something about my practice. I was telling this to Lindsey. Every time on our hospital service, we seem to have at least two patients with optic neuropathies, which I always enjoy, but I find it's a little weird to admit someone who's doing just fine otherwise to the hospital with three days of IV SOLU-MEDROL. So, I'm always trying to figure out, like, how can I get this patient home? And your article had the best term I've heard in a long time, which is “SOLU smoothies.” I mean, are there other strategies that you sometimes use, other than just high-dose IV methylprednisolone? Dr Eggenberger: So, I agree with you. It's sometimes hard to admit somebody for just an IV therapy. And we'll do this as an outpatient, high-dose IV, but we'll also use high-dose orals. And in times in the past when there's been methylprednisolone shortage, we've used high-dose oral or IV dexamethasone as well. I think the IV form, although it's the gold standard, the high-dose oral forms have pretty equivalent bioavailability and are pretty tolerable in my experience. And certainly more convenient. Dr Smith: I wonder if we should switch and maybe talk a little bit about aquaporin-4, I mean, you emphasized that this is a vicious disease---I love the way you describe that---and often blinding. What updates do you have in terms of our therapeutic approach to NMO? That's been rapidly evolving of late. Dr Eggenberger: Right, so these are cases we're always going to share with neuroimmunology. And it requires kind of a multidisciplinary approach, in my opinion, for ideal or for best outcomes. And so, all of these patients are going to get put on prophylactic medications. So, this is a disease you just can't leave untreated. Bad stuff will happen for sure. And we now, fortunately, have some approved, FDA-approved medications that can positively impact the course of this disease. So, that's been a welcome addition. Dr Smith: What are the FDA-approved medications at this point for NMO? Dr Eggenberger: So, there are several at this point, and this is an area that's in growth, fortunately. And again, these are cases we're going to be sharing with our neuroimmunology colleagues. So, these are IV medications typically aimed at complement or CD19. And they all are relatively effective at quieting the course of the disease. Dr Smith: Maybe we can talk a little bit about MOG? I think that most of our listeners are probably pretty familiar with aquaporin-4 and NMO, what- maybe you could describe MOG a little bit and the therapeutic approach for patients with MOG-associated disease? Dr Eggenberger: So, MOG has been a real interesting kind of condition to learn more about. We certainly see a lot of MOG, and I'm sure we saw MOG before it was formally described, but I think we just thought it was kind of a benign, maybe monophasic MS type of presentation. But MOG tends to come in with a loss of acuity that kind of rivals aquaporin-4. So, the acuity tends to be pretty, pretty depressed, but it's very steroid-responsive. So, a lot of times these are the patients, you'll see that their vision will start to improve even when they're on the initial few days of the high-dose steroids. And many times we can get their vision back to 20/20 or very close to that. Dr Smith: And do these patients need chronic management? Dr Eggenberger: So, that's an area of controversy to some degree. About 50% of the optic neuritis MOG-related cases are going to have a relapsing course. And because the disease is steroid-responsive, many times we'll follow these patients after a first attack to see if this is the condition that’s going to declare itself to be relapsing or if this is just going to be a monophasic kind of presentation of optic neuritis. We don't have great biomarkers to separate patients who are going to be in that 50% monophasic course versus the other half. It'll be relapsing. And so, it depends on the patient. If there's somebody that's, as many of these patients are, been very steroid responsive, they get back to 20/20, we can teach them about the disease so that if they do have a relapse, we can get them high-dose steroids in a relatively rapid fashion and they're otherwise healthy, we're probably going to watch that patient. And if it's somebody that doesn't recover 100%, there's other issues with treating them with high-dose steroids potentially in the future, then we may learn more towards an earlier prophylactic approach in that patient. Dr Smith: And what would that approach look like? Is it different from NMO or using more IVIG or B cell depletion as opposed to complement inhibition, for instance? Dr Eggenberger: In MOG, we know that the B cell depletion strategies don't work as well. And so most times we're turning to IVIG, and we found that pretty effective. That's kind of our go-to at this point. Dr Smith: Eric, it's a joy talking to you and I'd love to keep going about content, but I'll refer our listeners to your outstanding article. I mean, you're such a highly regarded neuro-ophthalmologist and educator. I wonder if you could talk to us about why you've done neuro-ophthalmology, and maybe this is an opportunity for you to convince all of our great residents that are listening or students what's great about being a neuro-ophthalmologist. Dr Eggenberger: I think neuro-ophthalmology is by far the most interesting part of neurology. So, it's an area that I think a lot of general neurologists, in my view, don't get enough of in their residency. But it's kind of the essence of neurology, where in neurology you're localizing down to the millimeter and in neuro-ophthalmology,  we're localizing down to the micron level. We have several new emerging diseases like these varieties of optic neuritis we're focused on. We're learning lots about those. You get to be involved in lots of different areas of neurology. So, we'll see not just demyelinating conditions, we'll see trauma as it relates to the visual system. And we'll see tumor, and we see all different flavors, stroke, and in any piece of neurology, commonly we'll have some vision aspect that we that we get involved in. So, we see a wide variety of conditions. So, I think it's been a really exciting place to be within neurology. And it's rapidly changing at this point. We're getting new therapeutics. So, it's, I think it's a great time to be a neuro-ophthalmologist. Dr Smith: Yeah, listening to you talk and just reflecting on it, it's really true. Neuro-ophthalmology does cover the entire span of neurology, right? I'm a neuromuscular guy and we see a lot of ocular myasthenia, which is another super exciting area. But we've been talking about optic neuritis, and your article talks about infectious causes and the paraneoplastic and a whole host of things. So, you're a great advocate and salesperson for your field. You convinced me. Dr Eggenberger: Efferent neuro-ophthalmology we love, we could talk about ocular myasthenia and other aspects for another hour. And we get involved in all kinds of cases: third nerve palsies, ocular myasthenia, trauma that involves the efferent system, all different aspects. It's really a great subspecialty, and you get to see a bit of all of neurology. Dr Smith: I'm trying to remember who it was, Eric. It was an attending of mine at medical school. I went to medical school at the Mayo Clinic in Rochester, and I want to say it was Manny Gomez, who was a very famous tuberous sclerosis person, who told me that neuro-ophthalmology was the most elegant specialty within neurology. That stuck with me. Thank you so much for joining me today. I really appreciate it. Dr Eggenberger: Thank you. I appreciate it as well. Dr Smith: So again, today I've been interviewing Dr Eric Eggenberger about his really wonderful article on optic neuritis, which appears in the most recent issue of Continuum on neuro-ophthalmology. Be sure to check out Continuum audio episodes from the neuro-ophthalmology and other issues. And listeners, thank you very much for joining us today. Dr Monteith: This is Dr Teshamae Monteith, Associate Editor of Continuum Audio. If you've enjoyed this episode, you'll love the journal, which is full of in-depth and clinically relevant information important for neurology practitioners. Use the link in the episode notes to learn more and subscribe. AAN members, you can get CME for listening to this interview by completing the evaluation at continpub.com/audioCME. Thank you for listening to Continuum Audio.

Dr. Lindsey De Lott, a neurologist and neuro-ophthalmologist at the University of Michigan, delves into the complexities of optic neuropathies. She explains how misdiagnoses can lead to poor patient outcomes and highlights the importance of precise clinical assessments. The discussion covers the critical role of neuroimaging, particularly MRI, in differentiating between conditions like ischemic optic neuropathy and optic neuritis. De Lott also shares insights on treatment strategies, including the effective use of steroids and tocilizumab.