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Continuum Audio features conversations with the guest editors and authors of Continuum: Lifelong Learning in Neurology, the premier topic-based neurology clinical review and CME journal from the American Academy of Neurology. AAN members can earn CME for listening to interviews for review articles and completing the evaluation on the AAN’s Online Learning Center.


Neuromuscular Emergencies With Dr. Casey Albin

Published: July 17, 2024, 10 a.m.
Duration: 21 minutes 47 seconds

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Neuroinfectious Emergencies With Dr. Alexandra Reynolds

Published: July 10, 2024, 10 a.m.
Duration: 19 minutes 33 seconds

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Traumatic Brain Injury and Traumatic Spinal Cord Injury With Dr. Jamie Podell

Published: July 3, 2024, 10 a.m.
Duration: 20 minutes 19 seconds

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Emergent Management of Spontaneous Subarachnoid Hemorrhage With Dr. Soojin Park

Published: June 26, 2024, 10 a.m.
Duration: 24 minutes 13 seconds

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Neurocritical Care for Patients With Ischemic Stroke With Dr. T. M. Leslie-Mazwi

Published: June 19, 2024, 10 a.m.
Duration: 20 minutes 53 seconds

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The Neurocritical Care Examination and Workup With Dr. Sarah Wahlster

Published: June 12, 2024, 10 a.m.
Duration: 22 minutes 49 seconds [IG1] \\xa0\\u201d right? We often do that in many patients. But I think in the right patient, it can really be life or death a matter, and it is the exam that really then drives a whole cascade of changes in management and detects the need for lifesaving procedure. I would say it depends very much on the process and what you anticipate, right? If you have, for example, someone with a large ischemic stroke, large MCA stroke, especially, right, then there\'s sometimes conversations about doing a surgical procedure before they herniate. But let\'s say, kind of watch them and are worried that they will, you do worry about uncal herniation, and you pay attention to the pupil, because often, if the inferior division is infarcted, you know, you can see that kind of temporal tickling the uncus already. And so, I think those are patients that I torture with those NPi checks and checking the pupil very vigilantly. I would say, if it\'s a cerebellar stroke, for example, right, then you think about, you know, hydrocephalus. And often patients with cerebellar stroke - you know, the beauty of it is that if you detect it early, those patients can do so well, but they can die, and will die if they develop hydrocephalus start swelling. But I think, often something I always like to teach trainees is looking at the eye movements in upgaze and downgaze because, often, as the aqueduct, the third ventricle gets compressed and there\'s pressure on the colliculi \\u2013 you kind of see vertical gaze get worse. But I would say I think it\'s always good to know what the process is and then what deterioration would look like. For example, in subarachnoid hemorrhage, where you talk about vasospasm - it\'s funny - I think a really good, experienced nurse is actually the best tool in this, but they will sometimes come to you and say, \\u201cI see this flavor,\\u201d and it\'s actually a constellation of symptoms, especially in the anterior ACA (ACom) aneurysms. You sometimes see patients suddenly, like, making funky jokes or saying really weird things. And then you see that in combination with, sometimes, a sodium drop, a little bit of subfebrile temperature; blood pressure shoot up sometimes, and that is a way the brain is sometimes regulating. But it\'s often a constellation of things, and I think it depends a little on the process that you\'re worried about.

Dr Berkowitz: Yeah, that\'s very helpful. You just gave us some pearls for detecting deterioration related to vasospasm and subarachnoid hemorrhage; some pearls for detecting malignant edema in an MCA stroke or fourth ventricular compression in a large cerebellar stroke. Patients I find often very challenging to get a sense of what\'s going on and often get scanned over and over and back on EEG, not necessarily find something: patients with large intracerebral hemorrhage (particularly, in my experience, if the thalamus is involved) just can fluctuate a lot, and it\'s not clear to me actually what the fluctuation is. But you\'re looking for whether they\'re developing hydrocephalus from third ventricular compression with a thalamic hemorrhage (probably shouldn\'t be seizing from the thalamus, but if it\'s a large hemorrhage and cortical networks are disrupted and it\'s beyond sort of the subcortical gray matter, or has the hemorrhage expanded or ruptured it into the ventricular system?) And yet, you scan these patients over and over, sometimes, and just see it\'s the same thalamic hemorrhage and there\'s some, probably, just fluctuation level of arousal from the thalamic lesion. How do you, as someone who sees a lot of these patients, decide which patients with intracerebral hemorrhage - what are you looking for as far as deterioration? How do you decide who to keep scanning when you\\u2019re seeing the same fluctuations? I find it so challenging - I\'m curious to hear your perspective.

Dr Wahlster: Yeah, no - that is a very tricky one. I mean, unfortunately, in patients with deeper hemorrhages or deeper lesions - you know, thalamic or then affecting brainstem - I think those are the ones that ultimately don\'t have good, consistent airway protection and do end up needing a trach, just because there\'s so much fluctuation. But I agree - it\'s so tricky, and I don\'t think I can give a perfect answer. I would say, a little bit I lean on the imaging. And for example - let\'s say there\'s a thalamic hemorrhage. We recently actually had a patient - I was on service last week - we had a thalamic hemorrhage with a fair amount of edema on it that was also kind of pressing on the aqueduct and didn\'t have a lot of IVH, right? But it was, like, from the outside pushing on it and where we ended up getting more scans. And I have to say, that patient actually just did fine and actually got the drain out and didn\'t need a shunt or anything, and actually never drained. We put an EVD and actually drained very little. So, I think we\'re still bad at gauging those. But I think, in general, my index of suspicion or threshold to scan would be lower if there was something, like, you know, a lot of IVH associated, if, you know, just kind of push on the aqueduct. It\'s very hard to say, I think. Sometimes, as you get to know your patients, you can get a little bit of a flavor of what is within normal fluctuation. I think it\'s probably true for every patient, right? - that there\'s always some fluctuation within the realm of like, \\u201cthat\'s what he does,\\u201d and then there\'s something more profound. Yeah, sorry - I wish I could give a better answer, but I would say it\'s very tricky and requires experience and, ideally, you really taking the time to examine the patient yourself (ideally, several times). Sometimes, we see the patient - we get really worried. Or the typical thing we see the ICU is that the neurosurgeons walk around at 5 AM and say, like, \\u201cShe\'s altered, she\'s different, she\'s changed.\\u201d And then the nurse will tell you at 8 AM, like, \\u201cNo, they woke up and they ate their breakfast.\\u201d So, I think really working with your nurse and examining the patient yourself and just getting a flavor for what the realm of fluctuation is.

Dr Berkowitz: Yeah - that\'s helpful to hear how challenging it is, even for a neurocritical care expert. I\'m often taking care of these patients when they come out of the ICU and I\'m thinking, \\u201cAm I scanning these patients too much?\\u201d Because I just don\'t sort of see the initial stage, and then, you know, you realize, \\u201cIf I\'m concerned and this is not fitting, then I should get a CT scan,\\u201d and sometimes you can\'t sort it out of the bedside. So, far from apologizing for your answer, it\'s reassuring, right, that sometimes you really can\'t tell at the bedside, as much as we value our exam. And the stakes are quite high if this patient\\u2019s developed intraventricular hemorrhage or hydrocephalus, and these would change the management. Sometimes you have these patients the first few days in the ICU (for us, when they come out of the ICU) are getting scanned more often than you would like to. But then you get a sense of, \\u201cOh, yeah - these times of day, they\'re hard to arouse,\\u201d or, \\u201cThey\'re hard to arouse, but they are arousable this way,\\u201d and then, \\u201cWhen they are aroused, this is what they can do, and that\'s kind of what we saw yesterday.\\u201d And yet, as you said, if anyone on the team (the resident, the nurse, the student, our neurosurgery colleague) says, \\u201cI don\'t think this is how they were yesterday,\\u201d then, very low threshold to just go back and get a CT and make sure we\'re not missing something.

Dr. Wahlster: Exactly. Yeah. I would say the other thing is also certain time intervals, right? If I\'m seeing a patient that may be in vasospasm kind of around the days seven to ten, for the first fourteen day, I would be a little bit more nervous. Or with swelling - acute ischemic stroke says that could peak swelling, when knowing which [IG2] \\xa0, I would just be more anxious or have a lower threshold to scan. Yeah.

Dr Berkowitz: Yeah - very helpful. Well, thank you so much for joining me today on Continuum Audio.

Dr Wahlster: Thank you very much, Aaron.

Dr Berkowitz: Again, today we\'ve been interviewing Dr Sarah Wahlster, whose article, \\u201cExamination and Workup of the Neurocritical Care Patient\\u201d appears in the most recent issue of Continuum, on neurocritical care. Be sure to check out Continuum Audio episodes from this and other issues. And thank you so much to our listeners 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 practice. And right now, during our Spring Special, all subscriptions are 15% off. Go to or use the link in the episode notes to learn more and take advantage of this great discount. This offer ends June 30, 2024. AAN members: go to the link in the episode notes and complete the evaluation to get CME. Thank you for listening to Continuum Audio.



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June 2024 Neurocritical Care Issue With Dr. Ariane Lewis

Published: June 5, 2024, 10 a.m.
Duration: 19 minutes 1 second

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Indomethacin-Responsive Headache Disorders With Dr. Peter Goadsby

Published: May 29, 2024, 10 a.m.
Duration: 23 minutes 27 seconds

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Cranial Neuralgias With Dr. Stephanie Nahas

Published: May 22, 2024, 10 a.m.
Duration: 25 minutes 42 seconds

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Headache in Children and Adolescents With Dr. Serena Orr

Published: May 15, 2024, 10 a.m.
Duration: 24 minutes

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New Daily Persistent Headache With Dr. Matthew Robbins

Published: May 8, 2024, 10 a.m.
Duration: 25 minutes

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Posttraumatic Headache With Dr. Todd Schwedt

Published: May 1, 2024, 10 a.m.
Duration: 23 minutes 57 seconds

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Cluster Headache, SUNCT, and SUNA With Dr. Mark Burish

Published: April 24, 2024, 10 a.m.
Duration: 23 minutes 13 seconds

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Acute Treatment of Migraine With Dr. Rebecca Burch

Published: April 17, 2024, 9 a.m.
Duration: 23 minutes 24 seconds

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Approach to the Patient With Headache With Dr. Deborah Friedman

Published: April 10, 2024, 10 a.m.
Duration: 19 minutes 59 seconds

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April 2024 Headache Issue With Dr. Amy Gelfand

Published: April 3, 2024, 10 a.m.
Duration: 19 minutes 46 seconds

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Symptomatic Treatment of Myelopathy with Dr. Kathy Chuang

Published: March 27, 2024, 10 a.m.
Duration: 17 minutes

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BONUS EPISODE: Continuum 2024 and Beyond

Published: March 23, 2024, 10 a.m.
Duration: 12 minutes 2 seconds

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Metabolic and Toxic Myelopathies with Dr. Kathryn Holroyd

Published: March 20, 2024, 10 a.m.
Duration: 21 minutes 4 seconds [IG1]\\xa0.

Dr Monteith: Yeah. What was that like when you were practicing in Zambia?

Dr Holroyd: I worked primarily with Dr Deanna Saylor, who is there funding and working with neurology residents, and we would see a wide variety of clinical cases but have very little real-time information. So, I really admire the residents who train and work in Zambia and have to make clinical decisions with very little information. In those settings, the history \\u2013 so, asking people about recent ingestions, any drugs, diet at home, any exposures that might cause increased risk of these conditions - is very important. And sometimes you have to rely on empiric treatments, such as vitamin B12, in cases where you may not be able to send for those tests - especially more specific tests, such as methylmalonic acid or homocysteine.

Dr Monteith: With your hospitalist experience, can you think of some cases, or like, one case that stands out that made you lose sleep at night, that you cracked the puzzle? Just so that we have this on our radar.

Dr Holroyd: Yeah, I think that there\'s some more unusual causes of toxic myelopathies. We saw a young woman who came in with a very acute, very severe myelopathy after studying for a test. She had a dorsal column-predominant hyperintensity, but all of her other diagnostics - lumbar puncture, everything else - was completely normal. We weren\'t really thinking of nutritional deficiencies because it was such an acute onset in such a young woman; we are really thinking this must be autoimmune or something else. And it actually came out that she had been ingesting whippets \\u2013 so, inhaled nitric oxide, which came out a bit later in the history. And we checked for a B12, which was very low, and it turned out to be a nitric oxide-induced vitamin B12 myelopathy, which can be seen but is relatively rare and really stuck out in my mind. Thankfully, she made a full recovery with the supplementation of vitamin B12 and cessation of drug use.

Dr Monteith: Wow, that is an impressive story. I\'m glad that was on your mind and you figured it out.

Dr Holroyd: Thanks. Yeah - team effort.

Dr Monteith: What should we take away about nutritional deficiencies?

Dr Holroyd: Nutritional myelopathies \\u2013 I think there are kind of the four main ones that we speak about in the article - vitamin B12, folate, vitamin E and copper - and I think these really have more similarities than differences. They all present clinically very similarly, with the subacute combined degeneration of the cord (the dorsal columns and the corticospinal tracts) - that\'s going to give you, basically, spasticity and upper motor neuron signs, as well as sensory symptoms (loss of vibration and proprioception). Weakness can be a part of it, but that\'s usually a bit later in the course. Secondly, they all have similar diagnostics. As I mentioned, the MRI is going to be normal in over 50% of cases of all of these, but when it\'s abnormal, generally they\'ll be a T2/FLAIR hyperintensity in the dorsal column, and that will be the most common finding. Often, we don\'t have a lot of lumbar puncture data from these conditions, but generally, when lumbar puncture is performed, it will be relatively normal or noninflammatory. So, those are some of the similarities. Some of the differences are the risk factors. Vitamin B12 - the risks are going to be mainly bariatric surgery, a vegan diet, or autoimmune pernicious anemia. Folate deficiency from nutritional causes is very rare, so that\'s usually going to come from someone with an increased folate requirement (sickle cell anemia or certain hematologic malignancies). Vitamin E often comes from malabsorption, as seen in cystic fibrosis, or abetalipoproteinemia, or hepatobiliary disorders. And then finally, copper generally comes from gastric surgeries or from excessive zinc intake, the classic example of being denture cream. I think one way to differentiate these is by looking at the person\'s risk factors. Finally, I think I tried to categorize them in my head in a few different ways with clues that might give you a specific clue. So, if someone comes in with a subacute myelopathy and they also have a macrocytic anemia, that would push you more towards vitamin B12 or folate. However, if they\'re presenting with a myeloneuropathy (so, that\'s upper motor neuron signs) but also a peripheral neuropathy on exam, you might think more vitamin B12 or copper. Then finally, if someone comes in with a myelopathy as well as ataxia, you might think more likely vitamin E deficiency. Those are some ways to categorize these that may otherwise appear very similar. But I think, at the end of the day, and someone with a subacute myelopathy and a nutritional risk factor, you\'ll end up sending all four of these blood tests to evaluate for appropriate treatment.

Dr Monteith: Well, let\'s move on to climate change. It\'s not often that we see climate change in a neurology article, but yet it\'s a thing that affects patients. Can you talk about konzo? I wasn\'t familiar with the term before reading your article, so thank you.

Dr Holroyd: Yeah, it\'s one of these that we debated - should we include this in the article (because it is relatively rare). But I think it is important to keep a global perspective. Konzo and lathyrism are the two nutritional toxic myelopathies that we talk about, but I\'ll just focus on konzo for brevity. This occurs in populations that rely on the cassava root for nutrition and generally occurs in times of drought, and that\'s because drought increases the cyanide content in the cassava root. After higher rates of ingestion, especially in people with protein malnutrition (so, a lot of children and young women), you can actually get a toxic myelopathy from cyanide. And the mechanism is not totally understood, but it tends to be quite acute onset, primarily with spasticity, impaired gait, and weakness. It will self-stabilize, but there really is no way to improve symptoms after it\'s occurred. It is relatively permanent. There really isn\'t a lot of data on MRI findings or CSF findings, but the few case reports that have been published, they tend to be normal. I think what\'s important is that there are very easy public health interventions to prevent these toxicities \\u2013 so, by simply increasing the wetting time of the cassava root (so, soaking it for longer), you can reduce the cyanide content and really effectively prevent this condition. So, I think the big picture takeaway that can be connected to a lot of other neurologic disorders globally is that we need to be aware of how climate change will affect our environment - and dietary changes, environmental exposures - and focus on early public health interventions to prevent these. So, how can we help prevent these rather than treat them once they happen.

Dr Monteith: Are we seeing more of it, or is it just better diagnosed?

Dr Holroyd: There\'s not great public health data on the rates throughout areas. It (so far) has only been reported in the African continent. There have been increases and decreases in numbers based on, I think, both the climate (so, times of drought or worse, malnutrition), but also, I think the reporting - I think it fluctuates not only with the weather but also with the amount of ability to publish on cases. So, I don\'t think we have a good grasp on whether, globally, their rates of konzo or lathyrism are increasing or not.

Dr Monteith: Then, heroin - we have to talk about heroin, right? It\'s just simply remarkable that close to a million individuals in the US over the age of twelve use heroin in 2020. So, now you just have to talk to us about heroin myelopathy because it\'s something that we could see.

Dr Holroyd: Absolutely. It\'s not something that I think most clinicians are familiar with as the complication of heroin use. But I\'m sure that heroin touches all of our lives as clinicians in any field. There are two types of myelopathy related to heroin. There can be a slower, subacute myelopathy with chronic use. But what\'s more common, actually, is in people who have a long history of heroin use and then abstain for days to weeks and then use heroin again. This causes a very acute-onset longitudinal myelopathy that often has MRI abnormalities as well and can affect both the cervical and the thoracic cord and be quite severe, affecting all modalities (sensation as well as weakness). The mechanism really is not well understood for this and, therefore, the treatments really aren\'t well understood, either. Some case reports have trialed IV corticosteroids, but really, there\'s an unclear benefit for this. Most people will regain some recovery of function, but often it\'s not full recovery, and some may have no recovery. I think the follow-up question to this is, as we see the composition of drugs change \\u2013 so, now there\'s a predominance of fentanyl, actually, whereas most of these case reports were from more traditional heroin. I was actually looking into it - this isn\'t covered in the article - but there has been one case report in 2019 about fentanyl use in someone who primarily used heroin, was abstinent for eight days but continued to use fentanyl patch, and developed an acute-onset, severe cervical myelopathy quite similar to this traditional heroin myelopathy. So, it seems like fentanyl will probably still have the same risks, but it\'s slightly less well understood at this point.

Dr Monteith: And important also for chronic pain \\u2013 just, like, poorly managed chronic pain that we might see, as you do during a hospital consultation.

Dr Holroyd: Absolutely, yes - especially because this was from a fentanyl patch itself.

Dr Monteith: Great. So, why don\'t you wrap up the most important clinical takeaways from your article?

Dr Holroyd: I think one takeaway that we haven\'t really focused on is that, actually, most of the primary literature on a lot of these topics, especially the nutritional topics, are twenty to thirty years old, and I think updated case series would really inform clinical practice. When it came down to it, actually - folate deficiency - we really only found four to five case reports in all the literature, which I really think is disproportionate to how much we learned about it in medical school and residency. I think, really, a better understanding of (in this era) what the prevalence of these disorders are, how they\'re presenting, and effective treatments, is really needed. I think that a lot of the exciting work will also occur in the field of oncology, with new treatments, with immune checkpoint inhibitors, and better understanding of how we can mitigate the risks of neurologic complications while still allowing patients the benefit of their cancer treatment. So, I think diagnosing toxic metabolic myelopathies early is very important. And in someone with a subacute, or even acute myelopathy without a clear cause, you should really delve into nutritional, drug use, demographics (kind of, where they\'re from) - all of these things that we often don\'t take time to do on history but might be more important in these cases because a lot of them are treatable - it\'s really important to get to those risk factors early on. I think that\'s what I would like clinicians to take away from our article.

Dr Monteith: Well, I think the article is fully packed with a lot of clinical tips - important tips - but a lot of public health relevance in a really special way that it was written. Any exciting breakthroughs that you\'re excited about or use of technologies to advance this area?

Dr Holroyd: Right now, there really aren\'t a lot of novel technologies in these areas, or diagnostics. I think, in the future, with some of the more cancer-related radiotherapies or intrathecal chemotherapies, the neuro-oncologists and oncologists will really be at the forefront of minimizing these toxicities. Again, I really think that\'s where a lot of the more advanced diagnostics will come into play. For the others, I think it\'s really about early diagnosis and public health awareness, especially as it relates to heroin myelopathy in the US.

Dr Monteith: Well, excellent, and thank you for being a part of that public health awareness. Thank you for being on the podcast.

Dr Holroyd: Thank you. Thank you so much for having me.

Dr Monteith: Thank you, Dr Holroyd for joining me on Continuum Audio. Again, today we\'ve been interviewing Dr Kathryn Holroyd, whose article on toxic metabolic myelopathies appears in the most recent issue of Continuum, on spinal cord disorders. Be sure to check out Continuum Audio podcasts 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, please consider subscribing to the journal. There\'s a link in the episode notes. We\'d also appreciate you following the podcast and rating or reviewing it. AAN members: go to the link in the episode notes and complete the evaluation to get CME for this episode. Thank you for listening to Continuum Audio.



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Immune-Mediated Myelopathies with Dr. Michael Levy

Published: March 13, 2024, 10 a.m.
Duration: 18 minutes 42 seconds

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Genetic Myelopathies with Dr. Kara Stavros

Published: March 6, 2024, 11 a.m.
Duration: 17 minutes 23 seconds

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Spinal Cord Neoplasms with Dr. J. Ricardo McFaline-Figueroa

Published: Feb. 28, 2024, 11 a.m.
Duration: 19 minutes 17 seconds

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Structural Myelopathies with Dr. Ligia Onofrei

Published: Feb. 21, 2024, 11 a.m.
Duration: 20 minutes 36 seconds

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Traumatic Spinal Cord Injury with Dr. Saef Izzy

Published: Feb. 14, 2024, 11 a.m.
Duration: 18 minutes 59 seconds

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Clinical Approach to Myelopathy Diagnosis With Dr. Carlos Pardo

Published: Feb. 8, 2024, 11 a.m.
Duration: 24 minutes 14 seconds

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February 2024 Spinal Cord Disorders Issue With Dr. Shamik Bhattacharyya

Published: Feb. 7, 2024, 11 a.m.
Duration: 20 minutes 59 seconds

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Welcome to the New Continuum Audio

Published: Jan. 31, 2024, 11 a.m.
Duration: 4 minutes 5 seconds

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