Continuum Audio

Circadian rhythms influence far more than sleep, affecting neurologic disease expression, treatment response, and overall health. In this episode, Dr. Sabra Abbott discusses common circadian rhythm disorders, the health consequences of circadian misalignment, and practical strategies for managing jet lag, shift work, and disrupted sleep-wake schedules. Learn how circadian biology can shape neurologic outcomes and why considering the timing of behaviors, light exposure, and treatments may improve patient care. In this episode, Katie Grouse, MD, FAAN, speaks with Sabra M. Abbott, MD, PhD, author of the article "Circadian Neurology" in the Continuum® August 2026 Sleep Neurology 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. Abbott is an Associate Professor of Neurology at Northwestern University Feinberg School of Medicine in Chicago, Illinois. Additional Resources Read the article: Circadian Neurology 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 Full episode transcript available here Dr Grouse: Circadian rhythm disruption affects many of our patients in far-reaching aspects of their general health and has likely personally affected most neurologists at some point in their career. Today, I have the opportunity to interview Dr. Sabra Abbott, who is the author of the latest issue of Continuum on Neurology of Sleep.  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. Sabra Abbott about her article on circadian neurology. This article appears in the August 2026 Continuum issue on Neurology of Sleep. Welcome to the podcast, and please introduce yourself to our audience.  Dr Abbott: Thanks for having me. I'm Dr. Sabra Abbott. I'm an associate professor of neurology at Northwestern, and I'm also director of our circadian medicine clinic.  Dr Grouse: It's really great to have you today. I definitely enjoyed reading your article, and not only did I learn a lot, but I feel like it's really applicable to a lot of topics that come up in clinic when I see patients. Now, I was wondering if you had to choose one key point that readers of your article would take away after reading it, what would it be?  Dr Abbott: I think the most important thing to keep in mind is that time is an important variable in every single thing that we do. And so, it can impact when your patient's disease is at its best and at its worst, and then it also can impact when it's actually most appropriate to provide medications for your patients. There can be times where they may be more impactful and times where they may actually cause more harm for your patients. So, the short answer is think about time always with your patients.  Dr Grouse: On that topic, I was really amazed to learn about the significant health risks associated with circadian misalignment, including even malignancy risks. Can you review some of these risks and why this might be the case?  Dr Abbott: So, I think the risk that we have the most data for is the risk for cancer associated with circadian misalignment, and this comes from a lot of studies that we're looking at patients who are shift workers. The data has actually come back on two separate reviews indicating that shift work could be a probable carcinogen, and we think that that probably comes down to a lot of different factors. So, when you're a shift worker, you are often working in the middle of the night. You may be getting light exposure at a time when you're normally producing melatonin, and that may be one factor that is actually putting you at increased risk for cancer.  Dr Grouse: And certainly, after reading this and hearing all of these things, I'm not surprised that many sleep specialists really dislike daylight savings time, which also is enough of a factor to potentially increase some of these health risks. Do you agree that daylight savings time is something that's contributing to poor health in our population?  Dr Abbott: So, I think it is definitely something that almost all of us want to get rid of, and I think where everybody is in agreement is that we should get rid of these shifts in the spring and the fall. I think the only benefit to those shifts that I see is it does create a time where we start having conversations about your circadian clock, so people become aware of circadian timing twice a year when we have these shifts. Outside of that, that shift back and forth seems to be very problematic. So, we do see both in the fall and the spring an increased risk for car crashes, an increased risk for heart attacks, stroke. People perform worse at work, and so I think in general, we probably should get rid of it. There's a little bit of a debate as to whether we should go to permanent standard time or permanent daylight saving time. I think most sleep and circadian scientists prefer permanent standard time. A lot of people who really like their evening activities prefer permanent daylight saving time, but I think that's also biased by the fact that daylight saving time, everybody has longer days, and I think they want longer days year-round, and you don't get that no matter which way you shift the clock in the winter.  Dr Grouse: That's really interesting. I do see that debate pop up every, I guess twice every year, and I guess there is a silver lining that at least we are all talking about it and thinking about it. I wanted to take a step back about the topic of circadian rhythm disorders in general. Could you just really quickly, like twenty-thousand-foot view, summarize what these main circadian rhythm disorders are?  Dr Abbott: So, at the moment, we primarily think of circadian rhythm disorders in the context of how they impact your sleep-wake timing. And so, at the largest level, we think of them as either intrinsic disorders, so disorders where your internal timing doesn't match up with the environment. The four key disorders there are advanced and delayed sleep wake phase disorders, so you're either earlier or later. You have non-twenty-four, where you actually generally get later and later each day, so it's like you're living on Mars. And then we have irregular, where you have multiple bouts of sleep that happen both night and day. And then the other two are the extrinsic disorders, so these are shift work disorders. So, you may have a normal functioning clock, but the external environment is forcing you to do things you wouldn't normally, or jet lag, where you again have a normal functioning clock, but then you end up having to shift multiple time zones faster than you can adapt to. Now, I think the interesting thing, and we can talk about this more if you want, is that we are moving into thinking of circadian rhythm disorders as being much more than just abnormalities of sleep-wake timing, and I think that's kind of where the future of the field goes.  Dr Grouse: Tell me more about that.  Dr Abbott: So, I think as the article gets into beyond just these kind of classically recognized disorders, we realize that circadian disruption can play a role in almost any other medical disorder that you can experience. And so, we can see circadian disruption as either a symptom or a potential cause of many other disorders. And then also in the optimal care of pretty much any patient, thinking about all of these other factors that they're experiencing on a day-to-day basis, whether it's their light exposure, whether it's the timing of their meals, whether it's the timing of their medications, all of those can play a role in their overall health and improving your ability to care for them.  Dr Grouse: Now, I did find it really fascinating. This was not something that I had really been aware of prior to reading your article about the fact that it really can make a difference about when you time particular medications for particular types of neurologic conditions just related to the circadian rhythm. And really interesting was the epilepsy connection. Can you tell me about how that affects how we should be dosing anti-seizure medication?  Dr Abbott: So, I think the epilepsy connection is an interesting one that definitely needs far more studies. So, at this point, a lot of this data is really coming from observational studies, looking at when patients have received medications and then how good their outcomes are. And in epilepsy, I think a lot of us tend to time anti-seizure medications so that patients get more of them in the evening and lower doses during the daytime. And I think a lot of this has been driven a little bit more by the fact that many of these medications are sedating, so we tend to put the more sedating medications at bedtime. But it turns out that outcomes in patients are actually better if they get higher doses at night and lower doses in the morning. Now, this is sort of theorizing at this point, but it could either be targets of these medications or your ability to uptake these medications across the blood-brain barrier may change with the time of day component. So, at this point, these are still really observational studies, but I think an area where we really need to do a lot more work.  Dr Grouse: Well, I look forward to hearing more about other ways that we'll learn how best to manage our medications for circadian rhythm function. Now, I wanted to ask, which

Hypersomnia encompasses a group of disorders characterized by excessive daytime sleepiness that can significantly impair quality of life and neurologic function. In this episode, Dr. Margaret Kay-Stacey discusses how to recognize and evaluate hypersomnia, reviews key features of narcolepsy and idiopathic hypersomnia, and highlights the many neurologic conditions associated with excessive sleepiness. Learn practical approaches to diagnosis, treatment, and distinguishing primary hypersomnia disorders from more common causes such as insufficient sleep, sleep apnea, medications, and depression. In this episode, Gordon Smith, MD, FAAN, speaks with Margaret Kay-Stacey, MD, author of the article "Hypersomnia" in the Continuum® August 2026 Sleep Neurology 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. Kay-Stacey is an Assistant Professor of Neurology and Ambulatory Medical Director at the University of Chicago Medical Center in Chicago, Illinois. Additional Resources Read the article: Hypersomnia 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 Smith: So, what do myotonic dystrophy, Parkinson's disease, and traumatic brain injury have in common? It turns out that each can cause clinically significant and meaningful hypersomnolence. And did you know that narcolepsy has the same population prevalence in the United States as myasthenia gravis, something I commonly see in clinic? If you want to learn more about hypersomnolence and how it impacts the patients you care for and what to do about it, keep listening.  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 Dr. Meg Kay-Stacey about her article on hypersomnia, which appears in the August 2026 Continuum issue on the neurology of sleep. Meg, welcome to the podcast, and maybe you can begin by just introducing yourself to our audience.  Dr Kay-Stacey: Yeah. Hi, I'm so glad to be here. So, like you said, I'm Meg Kay-Stacey. I'm a sleep neurologist at the University of Chicago. I'm also the AAN's Sleep Section vice chair.  Dr Smith: Awesome. I didn't quite know what to expect in reading your article, except it was gonna be about people who are really sleepy. I was really amazed at how common these problems are, even, we'll get into this, disorders that I think of as being super rare. So, I know our listeners are gonna really enjoy hearing from you. I wonder if you could begin by just defining hypersomnia and maybe give us a flavor for the impact this has on patients who have primary disorders of hypersomnia.  Dr Kay-Stacey: Yeah. I mean, so hypersomnia is really an excessive daytime sleepiness, so a feeling of excessive sleepiness, feeling like they can't stay awake during the day. And these patients' quality of life is quite impacted by these symptoms, and there's lots of different conditions that can cause it, but it can be quite detrimental to day-to-day living.  Dr Smith: I honestly am sleepy a lot cause I work too hard or stay up late, and sleepiness seems to be a very common symptom. How do you sort out when a patient's excessive daytime sleepiness is pathologic related to lifestyle and the extent to which it may be a sleep apnea versus one of the other disorders that we'll talk about?  Dr Kay-Stacey: Yeah. I mean, you really have to take a good history. So as neurologists, we know that, that we have to do that, but particularly a sleep history and really understand, first and foremost, how much sleep the patient is getting. Really important to understand, are they getting adequate sleep at night, right? Because chronic insufficient sleep can cause daytime sleepiness, right? And can make people appear like they might have a primary hypersomnia disorder when in fact they don't. So that's sort of first and foremost, and then it's assessing the other symptoms that they have. So, it's assessing nocturnal symptoms. You mentioned sleep apnea, so assessing for things like snoring and witnessed apneas, nocturia, and then assessing for what the quality of their sleep like. Is it refreshing? Is it not refreshing? How easy or hard is it to wake up in the morning? And then asking them again about daytime symptoms. Are you falling asleep inappropriately at work? Are, you know, you falling asleep while driving? Are you finding it hard to stay awake even after you've had a full night of sleep? To really try to differentiate what the symptoms might be from. And then it's also assessing things, sleep apnea, for example, physical exam findings. You know, are they obese? Do they have a larger neck circumference? Is the airway more crowded? And then we do have some measures, some scales, so there's the Epworth Sleepiness Scale that we'll use that assesses sleepiness, which is kind of a good way to at least initially assess how sleepy a patient might be during the day.  Dr Smith: So that's great, and we'll talk a bit about sleep apnea, I hope. But when I hear hypersomnia, I always think about narcolepsy, and I wonder if maybe we can begin there.  Dr Kay-Stacey: Yeah.  Dr Smith: I was super interested to learn how common this is. About as common as myasthenia gravis. Actually, the population prevalence number is exactly the same as myasthenia. My Monday morning clinic is mostly myasthenia. So how do we recognize narcolepsy? Cause I'm worrying that I'm missing it.  Dr Kay-Stacey: Yeah. So, narcolepsy, you know, there's two types. There's narcolepsy type 1 and narcolepsy type 2. So, narcolepsy type 1 is a little easier because you have cataplexy. But with both conditions, you're gonna see excessive daytime sleepiness. You're gonna ask about things like sleep paralysis, whether or not they're having sleep-related hallucinations, so hypnagogic or hypnopompic hallucinations. Are they having other sort of REM, intrusion phenomenon? You may also hear things like REM behavior disorder, so acting out their dreams at night, and then some degree of, you know, difficulty waking up in the morning, feeling like they need to nap. Naps are often more refreshing in patients with narcolepsy which is a feature that when we talk about idiopathic hypersomnia kind of helps to differentiate them. So, it's really just asking about sleepiness and assessing for these other symptoms that they can have associated with narcolepsy.  Dr Smith: I was also interested to learn that narcolepsy is the most common cause of REM sleep behavior disorder in young patients, which is pretty cool. But I wonder, you used a term that I've never heard of, and I'm betting some of our listeners haven't, which is REM intrusion phenomenon. Could you tell us more about that? Dr Kay-Stacey: Yeah. So, this is the idea that in narcolepsy, your sleep states are sort of, jumbled up, would be the way of thinking of it. You have these phenomenon where REM will persist into wakefulness. So, sleep paralysis is actually a perfect example of that, right? That you wake up and you feel like you're awake, but your body is still paralyzed, you can't move. Cataplexy is similarly a REM intrusion phenomenon, as are these hallucinations that I mentioned, the sleep-related hallucinations.  Dr Smith: So what pearls do you have for recognizing cataplexy? What's the spectrum of cataplexy?  Dr Kay-Stacey: Yeah. So, I think cataplexy, it's associated with emotion, right? And we most commonly think about it being associated with laughter, right, with positive emotion, but it's key to remember that it can happen with negative emotion too, with fright, being upset or angry. And usually when you're asking patients about it, you wanna phrase it to understand, are they having episodes where they feel like they have brief loss of muscle tone? And it can be subtle. It can be a head drop, their mouth opening, a hand dropping something, and it's brief. Usually it's seconds to just a couple of minutes. These aren't prolonged episodes, and they're not losing consciousness. They're awake, they're just having that brief loss of muscle tone.  Dr Smith: So, what about orexin? I'm particularly interested in how often it's necessary to do an LP and look for CSF orexin levels. Is that a common thing in your practice, or do you rely on clinical phenomenology in a, you know, polysomnogram with multiple sleep latency testing to confirm a diagnosis of narcolepsy?  Dr Kay-Stacey: Most commonly, you're gonna still do the PSG and the MSLT, obviously, because it's less invasive than doing the lumbar puncture. There are scenarios, right, where you may consider doing the LP. I think if someone has cataplexy and you're pretty confident in that and they have a positive PSG, MSLT testing done, you know, you really don't need the lumbar puncture, right? But if you're in that gray area that for whatever reason you have a really high suspicion they have narcolepsy, but for whatever reason the PSG, MSLT either couldn't be done or it was inconclusive, then I might think about doing the lumbar puncture. The other scenario is that there are some patients who have to be on REM-suppressing medications, like antidepressants, for example. In those patients, it can confound the results. And so, if you're not able to stop those for the MSLT testing,

Insomnia affects neurologic health, quality of life, and daily functioning, but effective treatments are available. In this episode, Dr. Brandon Peters-Mathews discusses a practical approach to evaluating chronic insomnia, highlights the importance of identifying contributing conditions such as sleep apnea and mood disorders, and reviews cognitive behavioral therapy for insomnia (CBT-I), the recommended first-line treatment. Learn how addressing sleep can improve outcomes across a wide range of neurologic disorders. In this episode, Katie Grouse, MD, FAAN, speaks with Brandon R. Peters-Mathews, MD, FAAN, FAASM, author of the article "Insomnia" in the Continuum® August 2026 Sleep Neurology 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. Peters-Mathews is the Section Head of Sleep Medicine at Virginia Mason Franciscan Health in Seattle, Washington. Additional Resources Read the article: Insomnia 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: @BrandonPetersMD Full episode transcript available here Dr Grouse: Insomnia may be one of the most common medical issues experienced by patients, yet our knowledge about how to manage it remains limited. Today, I have the opportunity to speak with one of the world's leading experts on sleep disorders, Dr. Brandon Peters-Mathews, about the latest issue of Continuum on Neurology of Sleep.  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. Brandon Peters-Mathews about his article on insomnia. This article appears in the August 2026 Continuum issue on Neurology of Sleep. Welcome to the podcast, and please introduce yourself to our audience.  Dr Peters-Mathews: It's my pleasure to join you, and I'm happy to talk about this article. I think it's an interesting one for most folks. I am a board-certified sleep neurologist. I practice at Virginia Mason Franciscan Health in Seattle. I did my neurology training back at the University of Minnesota and my sleep training at Stanford University. I've been in practice for more than thirteen years at this point. It's hard to believe, but it's exciting to be able to speak with you today.  Dr Grouse: This is definitely an important topic for everybody. Certainly, sleep and the lack of it affects all of our patients, and I can't imagine there's a single clinical neurologist who doesn't have to answer questions and help evaluate patients with this problem, so very high-yield topic for everyone. Now, having read your article, I'm curious if you had to choose one key point that you want the readers of your article to take away after reading it, what would it be?  Dr Peters-Mathews: Emphasize for my patients that insomnia is a condition that we can work through and resolve, that if we really can understand the underlying contributing causes and resolve those issues, we can typically improve sleep. It's a process. It takes time. It takes some attention and, and sometimes even testing to figure out what's going on. But if we can dial into these root causes, we can typically help somebody to sleep much better. As part of that, we often employ a therapy called CBT-I, which we'll talk about here a little bit later. But that also helps us to identify some of these contributing factors that are leading to the poor sleep.  Dr Grouse: And I definitely want to talk more about CBT, it's such an important topic. But even before we get into that, I'd love it if you could just walk us through a hypothetical case of a patient with insomnia. I think the type of patient that I think we've all seen in our clinical practice and somebody who says, "You know, I've had poor sleep. I've had insomnia for many years. I've tried all of the things you're supposed to try. You know, I've tried sleep hygiene. I've tried this. I've tried that. I've tried medications. Nothing seems to work." Could you walk us through how you would evaluate a patient like this and start to consider what to recommend? Dr Peters-Mathews: So, some simple information that we can gather, would be information about when they're trying to go to bed, how long it's taking them to fall asleep initially. If they wake in the night and have trouble getting back to sleep, how often they wake in the night. If they're experiencing early morning awakenings, their final wake time, and when they actually get out of bed in the morning. That gives me a sense of the structure of their sleep pattern and whether or not they might be spending an excessive amount of time in bed for their own sleep need at their current age. The other factors that we might consider are sleep disorders, and typically, I would assess for other symptoms that would point me towards sleep apnea or restless legs and occasionally other disorders of sleep. We wanna make sure we're not missing comorbid conditions that might be affecting that person. These often include mood disorders. Sleep and mood walk hand in hand, and so anxiety and depression are important to identify and treat if present. We also want to make sure someone's not suffering from chronic pain or other conditions that might be impacting their sleep. So, I take a broad approach. I ask the same questions to each patient that comes to see me. I wanna make sure I'm not missing some of these details. And then some of these folks will require testing to further understand their sleep. Others may move on to a different therapy, and long-term may require even other interventions, including medications, to fully resolve their condition.  Dr Grouse: You mentioned in your article circadian rhythm sleep disorders. How often are these really a factor in patients with chronic insomnia? And do you think that's something that we as kind of first-line clinicians should be screening for as well?  Dr Peters-Mathews: So delayed sleep phase syndrome is the most common circadian disorder, and these are folks who are night owls by nature. They often develop their sleep patterns, as teenagers, if not before, and they may fade away in the working years but come back in retirement age. I would say that's a very common condition. It may affect as many as one in ten people. The other circadian disorders are pretty uncommon, so advanced sleep phase syndrome, where somebody is sleepy early and waking too early, that may only affect one in three hundred people. There are other conditions that affect specific populations, like non-twenty-four circadian pattern affects blind people. Typically, half of blind people have that condition. There are conditions that affect the regularity of sleep, so an irregular sleep-wake pattern that might occur more in folks with maybe an advanced dementia. So, there are populations where these conditions can be fairly common, but among the general population, that night owl tendency is by far the most common.  Dr Grouse: That's really helpful. And just taking a step back, why is insomnia bad for us? So, we worry about this in our patients. We know it can make neurologic issues worse. But in general, like, what are the reasons that having poor sleep can affect our health? Dr Peters-Mathews: Yeah, and it's not enough hours, certainly quantity, but also quality of sleep that matters. And I tell people that sleep is a pillar of health, just like nutrition and exercise. It's the other main contributor to our health and well-being. And so, it has its fingers in almost every aspect of our health. Insomnia on its own is a risk factor for other psychiatric conditions, including depression, anxiety, even disorders like bipolar and schizophrenia. Folks with insomnia are more likely to have alcohol or drug abuse issues and are at higher risk for things like chronic pain, suicide and, and social and occupational dysfunction. So, it's a disorder that has a really profound effect on how someone functions during the day, and again, may take a toll on their health over time.  Dr Grouse: That makes sense, and I would assume that there are certain populations within our neurology practices where we should really be attuned to the risk of insomnia. Are there specific populations you'd recommend really make it a habit of screening for insomnia?  Dr Peters-Mathews: I was joking with someone recently that anyone with a neurological nervous system can have issues, impacted by poor sleep. There are certain groups, so chronic headache patients are perhaps one that might warrant a further evaluation and management. Folks with multiple sclerosis or Parkinson's may have physical conditions that lead to more discomfort in sleep, fewer movements of their body in sleep, issues around nocturia that would disturb their sleep. Certainly, those with dementia, Alzheimer's disease and other dementias. Parkinson's and Lewy body dementia overlap a lot, as does multiple system atrophy. That can point us towards other conditions like REM sleep behavior disorder, but also insomnia can be an important feature of those disorders as well. And then folks with stroke often have disturbance to their sleep and may develop insomnia after experiencing a stroke. So those are specific populations where I think the yield is high to be looking for insomnia and other sleep disorders.  Dr Grouse: Yeah, that makes sense. I think a lot of us think of insomnia as almost like, make sure we're not mis

Central sleep apnea is a complex and often underrecognized sleep-related breathing disorder that differs from obstructive sleep apnea by involving reduced respiratory drive rather than upper airway obstruction. In this episode, Dr. Ran Liu reviews the underlying mechanisms of central sleep apnea, including the role of ventilatory control instability, discusses its association with neurologic conditions such as stroke, multiple sclerosis, ALS, and myasthenic disorders, and highlights key considerations for diagnosis and management. Learn how emerging technologies, personalized treatment strategies, and advances in sleep medicine are improving outcomes for patients with this heterogeneous group of disorders. In this episode, Teshamae Monteith, MD, FAAN, speaks with Ran R. Liu, MD, FRCPC, MSc, author of the article "Central Sleep Apnea" in the Continuum® August 2026 Sleep Neurology 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. Liu is an Adjunct Clinical Assistant Professor at McMaster University in Hamilton, Canada, and an Adjunct Lecturer at the University of Toronto in Toronto, Canada. Additional Resources Read the article: Central Sleep Apnea 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 Guest: @SleepyNeuroDoc  Full episode transcript available here Dr Monteith: You may be familiar with obstructive sleep apnea, but central sleep apnea is often less understood and frequently underdiagnosed. In this podcast, we break down the key clinical pearls to sharpen your diagnostic reasoning, discuss why central sleep apnea matters, and to explore some of the fascinating advances transforming the field. 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. Richard Liu about his article on central sleep apnea. This article appears in the August 2026 Continuum issue on Neurology of Sleep. Welcome to our podcast. How are you?  Dr Liu: Good. Thank you, Dr. Monteith, for having me today.  Dr Monteith: Please introduce yourself to our audience.  Dr Liu: Hello, everybody. My name is Richard Liu. I am a sleep neurologist. I am working out of Toronto at both Sunnybrook Health Science Center and MedSleep. I did my residency at Queen's for neurology and my sleep medicine fellowship at Harvard University.  Dr Monteith: Great. And what got you interested in sleep?  Dr Liu: Thank you very much for asking. For me, sleep medicine is a field where essentially everything is connected. Certainly, impaired sleep can affect many other conditions, including many neurological conditions. And even within sleep medicine, when somebody has a sleep disorder, often the entire system is connected. So as an example, if you have insomnia and fragmented sleep and periodic limb movements of sleep, certainly these conditions can impact sleep apnea. And certainly, for today's topic of central sleep apnea, this is an extremely complicated disorder where it's a very in-depth integration between neurological and respiratory physiology, among other systems as well.  Dr Monteith: So, I guess you're kind of like the cornerstone, sleep being the cornerstone of neurology. Everyone has to sleep. That's for sure. Great. So why don't we talk about what central sleep apnea is, and how prevalent is it as a collective group of disorders compared to obstructive sleep apnea?  Dr Liu: So, one way to think about central sleep apnea is that this is a heterogeneous group of etiology. But the primary concept here for central sleep apnea is that there's a reduction in respiratory drive. This is in contrast to obstructive sleep apnea, where essentially this is some form of airway obstruction in the presence of relatively intact respiratory drive. And of course, there's mixed apneas where they may contain features of both. But of course, now we know that even obstructive sleep apnea, there's a certain degree of drive dependence somewhat blurring these distinctions. The overall prevalence of central sleep apnea is about five to ten percent of all patients with sleep- disorder breathing. And certainly, it could be higher in some neurological conditions, such as things like stroke, multiple sclerosis, and multisystem atrophy.  Dr Monteith: Great. So certainly, it's out there. Why don't you tell us about the objectives of your article?  Dr Liu: Absolutely. Thank you for asking. I think the main objective of this article is really to highlight that central sleep apnea is a complex syndrome resulting from a large group of heterogeneous etiologies. And of course, again, it could be associated with many neurological conditions. And really here, I want to highlight advancements, both medicine and technology, on both the side of diagnosis of central sleep apnea, as well as the multimodal targeted treatment.  Dr Monteith: And what do you want our listeners to take away from this talk and certainly your article? What are the key essential points?  Dr Liu: Thank you very much for asking. I think that one way of looking at central sleep apnea to etiologically divide this into both hypocapnic and hypercapnic central sleep apnea. And of course, loop gain being a major driver for a hypocapnic central sleep apnea, and that one can actually think about hypocapnic central sleep apnea beyond a phenotypic spectrum with obstructive sleep apnea, with many patients having overlapping features of both obstruction and central component. On the other hand, hypercapnic central sleep apnea, often also known as hyperventilation syndrome, can span etiology from chemoreflex dysfunction to a broad range of neuroanatomical localization, such as central nervous system, peripheral nervous system, neuromuscular junction, and muscle disorders.  Dr Monteith: And what are some of the symptoms of central sleep apnea? Do any of them differ from obstructive sleep apnea?  Dr Liu: Thank you for asking, that's an excellent question. So certainly, central sleep apnea symptoms can overlap with obstructive sleep apnea symptoms. And of course, given the large range of underlying etiology, often the CSA symptoms depend on the underlying etiology. There may be less snoring compared to obstructive sleep apnea patients, especially the hypocapnic CSA patients. Of course, these patients, like OSA, may have frequent awakenings, gasping and choking their sleep, and nocturia, and so on.These patients may have daytime sleepiness, insomnia-like symptoms, or they could be asymptomatic. Interestingly, the hypocarbnic central sleep apnea patients, they're a bit more prone to have the insomnia-like symptoms, whereas the hypercarbnic central sleep apnea patients, they tend to have a bit more of the daytime sleepiness and morning headaches.  Dr Monteith: You spoke about some of the neurological disorders that might be associated with central sleep apnea, like stroke and multiple sclerosis. What about some of the more traditional risk factors associated with obstructive sleep apnea or conditions associated with it, like obesity and hypertension? Or does that just mix the picture?  Dr Liu: There is many overlap between risk factors between obstructive sleep apnea and central sleep apnea, and certainly one of the things that I highlight in this article is really that often it's not just black and white, that this could be a spectrum with overlapping disease between both conditions. So certainly, in our neurological world, stroke is the most common thing that may be associated with central sleep apnea. But overall, cardiovascular issues such as heart failure, atrial fibrillation, these things can also be associated with central sleep apnea. And again, from the neurological perspective, if we were to divide from hypocarbnic versus hypercarbnic central sleep apnea, by thinking about the hypercarbic central sleep apnea, again, this is where we're thinking about hypoventilation syndromes. You know, anything that can cause neuromuscular weakness, this is something that we should have a high alarm for, that potentially there may be a hypoventilation component. So, things like any myasthenic syndromes and ALS.  Dr Monteith: Great. Why don't we also talk about the classification? When was the last time central sleep apnea's classification was updated, and what should we know about the classification?  Dr Liu: The most recent classification for central sleep apnea is written in the International Classification of Sleep Disorders, third edition. In this edition, it's classified with six central sleep apnea syndromes. So, these are the CSA with Cheyne-Stoke breathing, CSA due to high altitude periodic breathing, primary CSA, CSA due to medication or substance, CSA due to medical disorder without Cheyne-Stoke breathing, and treatment-emergent central sleep apnea. These classifications more so describe the circumstance of when CSA occurs. A more etiological classification that we can consider would be classifying them by the underlying pathophysiology, which is dividing this from hypercarbnic central sleep apnea versus a hypocarbnic central sleep apnea. Certainly, both set of classification are discussed in this article.  Dr Monteith: Yeah. You discussed at length, the major physiological factors that our audience is just going to have to read. I don't want them to hear this too muc

Advances in sleep technology are transforming how neurologists identify and manage obstructive sleep apnea, a condition that affects up to 70% of patients with certain neurologic disorders and can negatively impact cognitive and neurologic outcomes if left untreated. In this episode, Dr. Joyce Lee-Iannotti discusses the growing role of wearable and nearable sleep-monitoring devices, when home sleep studies are appropriate, and how emerging technologies are expanding access to diagnosis and treatment. Learn practical strategies for screening patients, interpreting sleep data, and partnering with sleep specialists to improve long-term neurologic health through better sleep. In this episode, Casey S. Albin, MD, FAAN, speaks with Joyce K. Lee-Iannotti, MD, FAAN, FAASM, author of the article "Sleep Diagnostics and Monitoring Technology in Obstructive Sleep Apnea" in the Continuum® August 2026 Sleep Neurology issue. Dr. Albin is a Continuum® Audio interviewer, associate editor of media engagement, and an assistant professor of neurology and neurosurgery at Emory University School of Medicine in Atlanta, Georgia. Dr. Lee-Iannotti is a Professor of Neurology at the Barrow Neurological Institute, University of Arizona College of Medicine, and Creighton School of Medicine in Phoenix, Arizona. Additional Resources Read the article: Sleep Diagnostics and Monitoring Technology in Obstructive Sleep Apnea 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: @caseyalbin Guest: @jleeiannotti Full episode transcript available here Dr Albin: Through the neurology of sleep issue, I think we have all been convinced that we all need better sleep, both for ourselves and for our patients. And fortunately, there is an abundance of new technology that can enable us to diagnose sleep problems, and then also make sure that our patients are getting the rest that's going to give them the best chance at a good cognitive recovery, and improve their cognitive function even if they are not currently suffering from a neurologic condition. Today, I am so excited to dive deeper into this topic.  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 Albin: Hello, this is Dr. Casey Albin. Today I'm interviewing Dr. Joyce Lee-Iannotti about her article on sleep diagnostics and monitoring technology in obstructive sleep apnea. This article appears in the August 2026 Continuum issue on neurology of sleep. Welcome to the podcast, I'd love to just start by having you introduce yourself to our audience.  Dr Lee-Iannotti: Sure. Thank you so much for having me, Dr. Albin. I'm Joyce Lee-Iannotti. I'm a professor of neurology at Barrow Neurological Institute. I am boarded in general neurology, stroke, and sleep, but I spend most of my time in the sleep world, so I jokingly say that I get more sleep doing sleep than I certainly did in stroke.  Dr Albin: Absolutely. I mean, wow, what a fascinating career, and I suspect that we're actually gonna get to some of how all of those pathophysiologies might overlap in the world of sleep. But you had the really exciting task of trying to distill this exciting, rapidly evolving field of sleep diagnostics, and I suspect it's relevant to many of the patients who end up in the neurology clinic, and I suspect that it's actually pretty relevant to many of our listeners who themselves might actually be wearing sleep tracking devices. And all of us probably wonder, well, how can we use that data to improve our own cognitive function and certainly make our patient's life even better? Before we even get into some of the meat and potatoes of this, I thought it would be really helpful for us to define some terms that come up in your article, one of which is wearables. We might figure that out, but the other is nearable. Walk us through what's a wearable, what's a nearable, how are they different?  Dr Lee-Iannotti: I'm happy to do that. First of all, the article is entitled Sleep Diagnostics and Monitoring Technology, and this was a super fun article for me to write because it's very practical, and it's generalizable to everybody. So, I'm going to start with a wearable, and a wearable is really a device that is simply worn on the body. And we're all familiar with wearables like smart watches, they're rings, they're patches, they're headbands, and the most validated form of a wearable that you've probably heard about is actigraphy, which we use in the sleep clinic.  Dr Albin: Tell us a little bit more. So, what is actigraphy? I've heard the word before, but don't actually know what it means.  Dr Lee-Iannotti: Actigraphy has been a tool that we've used in the sleep clinic for a really long time. Traditionally, we used it to monitor circadian rhythm patterns in people who are night owls or morning larks. And then more currently, we actually use it to track sleep patterns in people with suspected narcolepsy. So, before they come in for a sleep study, we actually have them wear an actigraphy for about a week just to get a sense of their sleep duration and their circadian pattern.  Dr Albin: Got it. And what is it monitoring? Our movement or the patterns that we may or may not make?  Dr Lee-Iannotti: It's really based on movement. You're exactly right.  Dr Albin: Cool. Okay, so most of this is based on gold standard monitoring with actigraphy. What other things can be incorporated into these wearable devices?  Dr Lee-Iannotti: Yeah, the technology is really advanced, and every day it changes, which is super exciting. So, on top of movement, these wearables can look at temperature. They can look at even EEG, like limited EEG, heart rate variability, and a really big word that we like to use in sleep technology, which is PPG, or photoplethysmography data, and that's really looking at heart rate variability and oxygenation, saturations, and following those levels as well.  Dr Albin: Wow, so you basically can get most of the data that you might have historically needed to go to a sleep lab to get.  Dr Lee-Iannotti: Most of them. They're still a surrogate. You'll hear me emphasize in the article as well that the gold standard remains the in-lab polysomnogram, but these are good surrogate markers that patients can wear long term to look at trends and patterns.  Dr Albin: Absolutely. And we're gonna unpack a little bit about who specifically those are best for and, really what it gives you in the clinic. But before we jump into that, what's a nearable, and how is that different?  Dr Lee-Iannotti: Yeah. Nearables are really exciting too. So, these are devices that monitor sleep but don't require direct contact on the body. So, these are devices that our patients will use, but it'll be at the bedside table. They're devices that actually go underneath the mattress, or they can be in, like, the ambient environment to detect sleep patterns.  Dr Albin: Oh my gosh. How is it doing that if it's not actually something you're wearing? Dr Lee-Iannotti: I know. It seems a little Big Brother-ish, doesn't it?  Dr Albin: Yes.  Dr Lee-Iannotti: So, they use a technology called radio frequency signals, sometimes radar, sometimes sonar, pressure sensors, even microphones, and they're picking up things like respiration, movement, snoring, and that's how they can decipher sleep patterns.  Dr Albin: Crazy. I mean, I guess the benefit of that is that it's less disruptive to the user 'cause it's not actually on them and having contact with them, and I suspect there's probably some downsides in terms of just it's a more limited data set you're getting.  Dr Lee-Iannotti: Absolutely. Yeah, you're exactly right. It's more convenient because it's not touching them, so, in theory, they're gonna sleep more comfortably. But I would like to think that the most validated forms of devices that we use to track sleep have to have some form of contact with the body, and this technology is new and probably needs a few layers of more sophistication to be as accurate as the wearables.  Dr Albin: Absolutely. I feel like we're going to have this conversation in five, maybe even less than that, years, and this data will have become like, oh, we all have something in our room that's monitoring everything. The world is crazy. All right. One of the places where your article really stood out to me is that sleep diagnostics have really taken off, particularly when we're thinking about obstructive sleep apnea. And I think we all might sort of scratch our heads and be like, "This is a neurology podcast. Why should I, as a neurologist, care about obstructive sleep apnea?" But I think you laid out a very convincing argument in the article. Walk us through why we should care about this.  Dr Lee-Iannotti: Absolutely. So, for neurologists, sleep matters, and I hope that my article translates that. Obstructive sleep apnea, which I'm gonna call OSA, is incredibly common in all of our neurologic patients, whether you see epilepsy, Parkinson's, stroke, Alzheimer's, neuromuscular, or even chronic headache patients. The prevalence of sleep apnea is as high as 70% in these patients.  Dr Albin: Wow. That's incredible. That is an incredibly high number.  Dr Lee-Iannotti: And if I can add, Dr. Albin, there's growing literature in multiple studies across the literature that show that untreated sleep apnea negatively impacts neurologic outcomes in our patients. So, it is really important to ask the question about sleep, and if the red flags pop up, to then screen f