All right. Oh, that's really bright. Man. Hi, everybody. Welcome. Thanks for being here. I'm Dave Sifu. We're self-introducing. That's how sophisticated we are. I'm the chair of rehab at VCU. I'm also very active in the Richmond VA and the VA nationally. And today, Dan and I are going to be, as you probably know, that's why you're here, talking about the role of biological markers in traumatic brain injury. And apparently, I'm the pro. I didn't know that. I'm saying that they're important, and he's going to say that they're not. But we usually end up somewhere in the middle. So today, I'm going to be talking about all prospective longitudinal big data that's from the military and the VA. And all of this is published already. All the references are in the back. So for the most part, it isn't just my opinions, which often these lectures are. My disclosures, I have a lot of them, which is really good. None of them have influenced any of the information presented here. Most important thing in my life this year has been my brother's hockey team, the Florida Panthers, won the Stanley Cup. So I got to drink out of the cup and kiss the cup, and the CFU name is forever on the cup. That's kind of cool, I guess. What we're going to be talking about today and what I'm going to be talking about is give you a quick background on what LIMBIC is, the Long-Term Impact in Military Relevant Brain Injury Consortium. And then we're going to be talking about some of the data that's contained in there, specifically looking at biomarkers. In this case, biomarkers are going to be actual fluid biomarkers. I hate this word, but I'll say it, advanced neuroimaging, so MRIs, as well as electrophysiologic data. And we're going to be looking to, and I'm going to be talking about the relevance of it. And then importantly, because this is way more important than publications or research, is what do I do with that clinically? Whether you as a clinician now or someone that you're talking to that maybe works with this population, one of the challenges is, and I hate the blind people, the six blind people and the elephant, but it's relevant here, is if you just take a single biomarker or if you just take a single physical exam evaluation or a single X, Y, or Z and you're looking at someone with a traumatic brain injury, even a mild one who may or may not have other concomitant issues, you're never going to figure it out. It's kind of silly to say we're going to use a fluid biomarker to diagnose TBI when we have ears and mouths, all right? That's how you diagnose a TBI, right? But can using a combination of those factors help you to direct individualized treatments? Can it be used to prognosticate or can it tell you that this person is actually doing well and let's give them more of something or try something different? That's what these biomarkers I'm going to be talking about today can be used for. You can never use a single one, please, no. There's not a single, stop. There's no MRI, there's no fluid, there's no electrophys, all right? And I don't, I mean, I can prove it to you, I'm going to hopefully do it today, but that would just be inane. Like, it's the human brain, like it's not like the toenail, like it's fairly sophisticated, so you need a complex set of things. This is, I work in a 200-year-old building called the Egyptian Building. I'm on the second floor where the arrow is, and it's kind of, but Richmond isn't, that's where I'm based. I'm going to be talking about nationwide research, but this research is centered out of VCU and the Richmond VA, but that's my little temple there in the middle. Most days I'm the only person there because we're almost all virtual, but it's a cool building if you're ever in town. So Limbic Sensi, Limbic is the current version, Sensi is the original. We've been up and running 11 years. We're a nationwide consortium looking at individuals that have all had combat exposure, 80 percent have had one or more TBIs, 80 percent have never had a lifetime TBI, so we have a nice comparator sample. That's one of the major studies of Limbic. We also have a massive retrospective data set of all EHR and other data that's available in the DoD and the VA. We have 2.5 million unique veterans with 20 plus years of data. Our prospective longitudinal study has got 3,156 individuals in it, all again who have been in combat, 80 percent have had one or more TBI, 20 percent never had a TBI in their life as best we can identify. So we've got those folks that we're following longitudinally over time, obviously. Those folks are at least two years out from their last TBI, so we're not looking at acute concussion. I can tell you about acute concussion separately, but we're talking about what are the long-term concussion issues and then how do we use biomarkers. And if you have any interest in ever looking at the website, it's www.limbic-sensi.org, and all these publications, all the data we're talking about is on there. It's a nationwide program. The site in Hawaii is where we do our retreats. Now we have audiology specialists there, but it's truly representative across the nation. And while this is a military and veteran population, we're finding very similar things in parallel civilian groups we have. So don't just think this is just for veterans. Obviously blast injuries are going to be more unique to service members, and we have some data on that, but it should be relevant to all. The next three slides are just the areas that we're going to be looking at. It's going to be fluids, imaging, and then electrophys. So from a fluid standpoint, we have serum and saliva on all the individuals on entry into the study, and then every five years we do that again. Every year in between we're doing a telephone or video evaluation to look at how they're doing clinically. We have a lot of data on these people over the last 11 years. Most of their injuries now, because the war's been over for a bit, are five-plus years out. Some are 20 years out. We have a large data set, and that's what we're going to be presenting on. In addition to fluids, they also get advanced neuroimaging, or they get very sophisticated MRI evaluations, and I think we have probably like 6,000 or 7,000 MRIs taken longitudinally on the 3,000 people. So we've got two to three each, so we've got serial data as well. And the last thing is the physiologic measures we use are computerized eye tracking, computerized posturography, and we're doing different types of evoked potentials in EEG. And 11, 12 years ago when we came up with this grand scheme, we just picked tools that were readily available, all right, but we got lucky that these are ones that are still of high interest, particularly to Congress. So let's look a little bit at what data came out of what we've done so far. I've finally reached the age. All right, so I'm not going to read the slide because you all probably can read it as well as I, and I'm not going to talk about each of the individual biomarkers. I'm going to jump right to the clinical relevance. Again, these slides are available. You can read it. The papers are available. But the first sections of biomarkers we talked about, the ones that may be indication of ongoing or chronic inflammation. And what we found is that for individuals who have a single TBI versus no TBI, but particularly those that have multiple TBIs, three plus seems to be some threshold. It seems like a weird number, but when we break down the data, if you have at least three MTBIs, or if you've had one TBI but you have a lot of neurobehavioral symptoms, a lot of PTSD issues, a lot of dizziness still, a lot of headaches still, and the last thing is that if you have cognitive impairments, so TBI plus cognitive impairments, TBI plus neurobehavioral issues, TBI plus sleep disturbance, you're going to have a significant number of inflammatory markers. I don't know that you needed to give us $116 million to prove that, but it's proven, all right, that people with and people without TBIs also have difficulty if they have some of these symptoms, but not to the same extent. So there is something going on here. I thought I'd never say that in a public forum. There is something going on in biomarkers that we can find that have inflammation. But now it's our job, it's your job, it's everybody's job to figure out what do we do with it, all right? What can we implement? And we're not going to use it to diagnose TBI. They're three to 20 years out. They told us they had a TBI in the interview, so I don't find that a challenge. But now what we need to do is figure out how can we individualize treatment and use one or more of these measures to monitor that to prove, yes, they're recovering, no, they're getting worse, or they're staying the same, and change what we do. Dan and I were talking before. It's like we have all these amazing tests you'll see in the next couple slides. We found something on imaging too. It's incumbent upon us to now say, how do we change their treatment? Or say this person doesn't seem to have a lot of active inflammation, or the next slide talks about biomarkers that may be linked with neurodegeneration. This one we're actually really not finding anything relatively acute. We're finding that as people age, they get greater evidence of brain-linked neurodegeneration biomarkers, but that's not because of the injury they had 20 years ago. Because of their aging with a brain that's perhaps, a brain that's injured and perhaps is still having a lot of symptoms. So now we have markers. If you wish to use those, you can also just be asking the person how they're doing on a symptom inventory and monitor that. But if you want something more physiologic, the last slide and this slide have specific biomarkers that have consistently been found in people with TBI, usually multiple TBI, and yes, blast TBI, not a big civilian concern. But now we can at least have something to titrate treatments. So we're the treating, you know, we're PM&R. We treat brain injury. We need to figure out how to alter our treatments. I'm going to try to help you with that. That's the next phase of our research, is we have a number of ongoing prospective RCTs using this data set because we have great baselines. Now we're going to see which kind of folks do well with which treatments. The biggest one right now that we're seeing a nice signal on is autonomic dysfunction using heart rate variability biofeedback. So if you don't do a lot of HRV in your practice for TBI, it's something to consider. In neuroimaging, we actually found that similar areas, specifically blast, we're seeing parts of the brain in people with, obviously, TBI, but with and without neurobehavioral issues, we're seeing alterations in neuroimaging specific to blast and associated with cognitive dysfunction. So blast-related trauma is real. TBIs have always been real, but now just the blast effects in addition are real. In individuals that have cognitive issues, there are subsets that have neuroimaging abnormalities. Whether these will get better over time with cognitive interventions, we will figure out. That's the study now, but we can demonstrate abnormalities. And particularly folks that report a second group is those that have never had a TBI, but have had repeated blast exposure. And those are the ones we've been reading about in the New York Times Sunday edition. People who are shooting artillery and large guns and reporting long-term blast exposure without ever having a TBI. We're also seeing that those individuals do have a signal on MRI. I believed them when they told me they were having difficulties, but now we can say, not only do I believe you, but the imaging and the fluid biomarkers do support that there is something about having repeated exposure. Similarly, repeated exposure to behavioral dysfunction, PTSD, depression, long-term exposure to not sleeping, insomnia, commonly seen both after blast injury in individuals in the military as well as just those with TBI. There is a reason to be treating those things. We see a greater number of white matter hyperintensities in these individuals as well. And we're also seeing a linkage, not a big surprise, in those individuals that have mental health issues and TBI, as well as those that just have mental health, particularly PTSD, on imaging. All right? So, again, I guess it feels better that, yes, they actually do have a problem. Again, you keep shaking your head. I believed them when they told me they had a problem, and I was taking them seriously. I always like to put a pitch in here. Physiatrists need to feel comfortable with taking care of the entire range of problems people have, not just the brain injury ones. Well, they're all related. So feel comfortable with mental health care, substance abuse, right? Clearly, we should feel comfortable with prescribing exercise, too, which is one of the best treatments for mental health dysfunction. But please don't turf these people. Be fair with mental health professionals if you don't feel comfortable. But we're really good at taking care of mental health issues. It's called rehab. All right? It's amazingly good at it. All right? Not that mental health professionals aren't good, but we can kind of work with them and kind of do both, because a lot of mental health professionals don't feel comfortable with the brain injury piece, but they do feel comfortable with the mental health. We need to feel comfortable with both. All right, electrophysiologically, this one I'm not as big of a believer in, because this is like abstract art, all right? And I'm not saying just to me, but even to the people that seem to be evaluating it. And if you've ever used quantitative EEG, man, you can see a lot of things there. All right? You know, I always see, you know, abstract thoughts, but my researchers have identified there are specific areas on Queeg that are supportive of more significant traumatic brain injury, so longer LOC. They're associated with people that have persistent cognitive deficits. So there is a signal there. It's just very hard to access, whereas fluid markers and imaging is something that's a little bit more accessible to all clinicians, if you wish to use it. I don't recommend this, but this is now, we've got three different parts of the elephant we're looking at. And they're demonstrating that there's electrophysiologic changes. We've demonstrated there's imaging and there's biomarker changes. And so you can use any of those modalities to monitor them, if you wish. And I think lastly, because we don't have data yet on the eye tracking, computerized posterography, that's something that's fairly accessible to most folks. Three or more TBIs, significant decline in their sensory organization tests, so in their ability to balance well and to integrate their different senses, vision, proprioception, and kinesiology, proprioception and their balance. And we are not seeing a blast change, but we are absolutely seeing that it's repeated TBI. So if someone comes to you and they're playing football or they're on the job site or in the military and they're saying, Doc, I'm falling, particularly at nighttime, all right, or I fall less when I'm in bare feet than when I'm wearing shoes, all right, take that seriously and work with them and a physical therapist, a kinesiologist, to enhance it. Because the interventions work for these individuals. We haven't fully proven that yet. But they're not just saying it, and it's a very high risk factor for them for a lot of reasons. Whether it decreases their exercise abilities, whether it puts them at risk for falls, whether they just get kinesiophobia and don't leave the house because of that. And our cohort, 30s to 40s, all right, they started in their 20s, but so these are not nothing wrong with being 60, Terry, but 60, 70 will also have this, but 30 and 40-year-olds are having this problem. Terry's had it for a long time. And for the military, we've put together a list of what we found in blast TBI. Yes, they're a distinct group. Doesn't make me treat them any differently. I'm just more aware of that if they tell me they've been exposed to a blast. Even if it's a sub-threshold blast, no TBI. They may have said they felt a little buzz. And all these slides are available online. You can take a picture, too. And they're all in the publication. And this one gets everybody's attention, is that individuals that have TBI are at higher risk of suicide, particularly, obviously, veterans we're speaking of. Individuals with blasts but with TBI are at the highest risk. And it's significantly different than the baseline. We all know this. We hear about it. These are things we can do things about as PM&R docs. And you don't have to be a psychiatrist. You don't have to just treat their mental health issue. Get them back to living, right? We know this, right? Get them exercising, get them working, et cetera. So long story short, we have a massive retrospective data set where that last slide came from. That's published data as well, 2.5 million individuals, about 3% with TBI, the rest without that we can identify, as well as a large perspective longitudinal database. So all of these data are level one. This is real stuff, all right, which is so this is stuff you can kind of say, oh, I should figure out how to use that in my practice. And we are finding that these biosignals have relevance. If you would like to use them because you need to justify more interventions or for your own sake, you know, you've got the information here, but really their symptom profiles are reflective of that. We're not seeing people with no symptoms who have really hot biomarkers, all right. These people are symptomatic and, you know, chicken and egg, it's likely that the symptoms are driving the biomarkers as much as the TBI, all right, and that's what we're looking to investigate now. And last thing is we can now use this to either stratify people into different types of treatment, perhaps help them prognosticate. We're still figuring that out. Right now we have a subset that all received some type of treatment, but for the most part we're not getting ongoing services unless they were in a new research trial. They were past their therapies, but about at least a third of them were still having significant symptoms. And if you want to take a look at any of the websites, they're here. All of these data are available in the Knowledge Translation Centers. You can download papers, you can see synopsis. We have little, not for anybody in here, of course, but we have like one-liners for like what is this paper actually saying, so you don't have to read the whole paper. We've kind of summarized that for folks as well. So thank you very much. I'll turn it over to Dan. Thank you. That was incredible. I was the genius that decided to go second, and I've spoken enough with Dr. Sifu to know better than that. So that was my mistake. If we could pull up my slides. So when we structured this series of talks, we decided to have more information in the slides because you guys can download that later. But we thought this would be more interesting as a conversation. So we wanted to basically have presentations, but a lot of room for question and answer and discussion. It was what we were hoping to get. So I also wanted to start by saying I almost didn't make it here because four weeks ago my wife gave birth to our third kid. I have a map here of our house, which is that Century Hill place there. And that's the hospital, the red dot there. So we were walking to the hospital, and my wife was saying, like, I don't think I'm going to make it. And I said, you can do it. And she said, I don't think I can make it. I said, you got it. Absolutely, you can do it. And she said, I'm not going to make it. The baby's here. And she was right. And we found where that arrow is, that seven minutes, that in the middle of the street on the median, my wife, I delivered our third kid. So just so you know that this really was in Boston. That's the spot that it was. And that's right in front of a Dunkin Donuts. So deliveries run on Dunkin, I guess. And so, yeah, we had a story in the press about it, which was funny. This is like the same week that I was on NBC Nightly News with Lester Holt and ESPN and CNN, all at the same week. And then this came out. And my co-worker's like, oh, we saw you in the news. It was the delivery, like my kid. But everyone's doing great. And that's why they say the third kid's the wild card. So with that, disclosures. I don't, I guess I have a medical advisor to Ostatidex, which is a biomarker company. I'm not talking about their stuff here. But nothing else is particularly germane to this. So we're going to be talking about brain injuries. And when we're talking about biomarkers for brain injuries, largely what we're talking about is concussion, blast, that kind of thing. Because with a moderate, severe brain injury, you don't really need a biomarker to let you know that it happened. The biomarkers are more useful for prognostication. And so there is some of that. And then we'll talk about some of these technologies specifically. But what makes something useful? So I'm basically arguing on the side of things that these biomarkers, at this point, aren't particularly great. And it's often because they don't meet one of these characteristics, one or more of these characteristics. We want something that you can get relatively easily, and that either tells you something immediately or tells you something long term. And it has to be pretty consistent, right? It has to be something that is sensitive and specific for the outcome you're trying to assess. And I think, then, let's take a look, then, at what is going on in a brain injury so we can try to figure out what these biomarkers are trying to look at and how they're specifically picking up those different aspects of the process. And so this is a cartoon of a neuron. You normally have your electrical signal is converted into a chemical signal so that information can go from cell to cell. But after a brain injury, you have disruption of multiple factors, including the cell membrane, which causes massive efflux of potassium and influx of calcium, which leads to a dysregulated state. And this is what our biomarkers are largely taking a look for. Because when this happens, you can have damage to the neurons, damage to the supporting structure of the cells, neuroinflammation. You can have all of these other processes. And in the vast majority of concussions, these resolve. But we know that some people have persistent symptoms. We know that there are issues that occur. And what we'd ideally have is a biomarker that lets us know when that's more likely to occur or not. And so here, this is a cartoon that depicts the different areas that can go awry after a brain injury and what some sample biomarkers are for each of those domains. And I'll talk about these in the next bunch of slides. But the slides are, again, here for your information all posted online. But when we're talking about these, then there's some general limitations to these biomarkers. So a lot of the studies of biomarkers are looking at athletes. And in particular, some of these different factors change when you're exercising. And so when you're trying to assess something, the validity of something in the diagnosis of a brain injury, if it increases following physical exertion, then that's problematic. Similarly, they have variable times to peak onset. And so they each give us a window into different aspects of the brain injury. And this is actually something that echoes exactly what Dave said, where I don't think that there's one biomarker that's really going to tell us everything. But you can potentially envision a system where there's multiple biomarkers that each tell us something about the different process of where an individual is in their recovery. And then that fingerprint, that series of biomarkers on a chip, might be the useful information for prognostication and other factors. A lot of these biomarkers are looking at adults, college people, military veterans, sorry, active-duty military individuals, veterans. And so extrapolation to pediatric populations, where the vast majority of concussions occur, is something that's also important. Also, most of these studies are in men. And so there's going to be differences based on that, especially because we know that there are endocrinologic differences between men and women. And so that could relate to how these biomarker levels appear, and both the sensitivity and specificity of these markers. Many of these things change with age. The aging brain has its own release of biomarkers, and so a 50-year-old's response to a brain injury isn't necessarily going to be the same as a 20-year-old's in terms of biomarker elevation. And so that's something that we need to be aware of. Certainly, as you're talking about athletes, if they're exercising, they are dehydrated, and that might concentrate the levels of some biomarkers in their blood. Mental dysfunction can cause problems, and symptoms, I think, might not manifest for all injuries. And I wanted to harp on this for a second. So there's been a number of helmet sensor studies that have looked in real time at this point, like 7 million head impacts that have been recorded by head impact, by this specific system, the head impact telemetry system. And these studies have shown, pretty conclusively, that head impacts don't predict whether or not someone has a brain injury. And a brain injury, we're diagnosing that based on the presence of symptoms or signs after a hit to the head. So I can get an ADG hit to the head and have symptoms and data get the exact same ADG impact to the head, the exact same area, but have no symptoms, and I had a concussion and he didn't. And based on that helmet sensor data, they've actually gone back and looked at the number of head impacts that a person got who had a concussion. And so in this figure, we recreated some of those data, where the green helmet there represents an individual who got a concussion. And they went back and looked at all of the head impact characteristics, based on helmet sensor data, that that person who experienced the concussion was hit with. And what they found is, on average, for every concussion, a person gets 341 hits in the collegiate football level of equal or greater magnitude than the hit that gave them a concussion. So one of the ways that biomarkers might fail is because it's entirely possible, if you have 84 billion neurons in your brain, that you could damage 10,000 or 100,000 of those neurons, right? And that 100,000 represents 0.00001 of all the neurons in your brain. So 100,000 damaged neurons might just not occur in a salient part of the brain that would result in symptoms that we're aware of, right? It could just be happening in another part of our brain. And these other impacts might end up being something that are causing injuries that we're not capturing, and that are resulting in biomarker elevation. And that might make our biomarkers look worse than they are, right? Because we're capturing injuries, but we're just not calling them injuries. And so that's where I propose new terminology for describing these. Right now, we talk about concussive impacts and sub-concussive impacts. And I think that the name sub-concussive is a misnomer because it doesn't reflect the fact that many of these impacts are actually technically supra-concussive, right? They're occurring at a higher force than our concussive impacts. And when you give them this idea, this name sub, it puts them on this lower trajectory. We talk about a bunch of little hits, but we're actually talking about really big hits too. And so I argue that we should be calling them non-concussive impacts. When we're talking about injuries then, right now, we have concussion and we still talk about sub-concussive injuries too. And in that way, we conflate this idea of the impact and the injuries. I think we also need to separate those. And instead, borrow the language from other neurologic processes. So for example, with stroke, you can have a CVA, but you can also get a subclinical cerebrovascular accident. You can have imaging changes that show up after someone gets a lot of these subclinical CVAs, and that result in increased risks of vascular dementia. Same thing for multiple sclerosis. You can have subclinical lesions as well that don't manifest because they're probably not affecting salient areas of the brain, but we recognize that those are causing injuries. And so we need to use the same terminology, I think, and talk about traumatic brain injuries with concussion, which is a mild TBI, and then a subclinical traumatic brain injury to help us define all these other injuries that are occurring. But again, the reason why this is relevant for biomarkers is that that's what I think what some of our biomarkers are picking up, and that's why some of these biomarkers don't look as good as they are. So I'll then spend the next few minutes talking about some different types of biomarkers, but blood biomarkers, really none of them are currently used for prognostication of TBI. There have been three that have been used for the determination of whether or not someone needs a CT scan. In this country, UCHL1 and GFAP are approved. S100B is approved in some countries in Europe, predominantly in Germany, is used. But there's some issues, as we'll talk about with S100B next. And there's also been some exciting updates in the definition of concussion severity that reclassify it based on, instead of the Glasgow Coma Scale, potential use of biomarkers as well. So S100B is the first one, this is one, as I said, it's not FDA approved here, it's predominantly used in Europe. And so it's looking at the support structure of the cells. And there's been some data that basically show that it isn't super sensitive to changes, especially when you're looking at a given athlete in front of you. It's better in the aggregate level. If you get a group of rugby players, for example, so there was a study in neurotrauma in 2021 that consolidated a group of rugby players and found that there was a significant elevation in S100B at an hour after injury, but a day later there was no significant changes. And really this was significant when you had the whole group of rugby players, but there was a lot of overlap between the two cohorts. So that makes it, I think, a little less useful on a patient-in-front-of-you basis, which is where we mostly are working. There's GFAP. So this is another marker of the support structure of the cells. And a lot of the work that's been supporting the use of GFAP has been out of the CARE Consortium. It's been pretty incredible looking at both collegiate athletes and military cadets. And it's shown some support, again, in the aggregate identification of individuals. The real benefit of this is for determining whether or not someone has a bleed. I should say a quick aside, I think, because there's been limited implementation of both GFAP and UCHL1 for that use case for which it's FDA approved. And I think part of that is that in medicine we tend to be conservative. We want to make sure that that risk of missing the patient with a brain bleed weighs heavy on all of us. And so without proper guidance, I think, from clinicians that specialize in neuroinjury, emergency room physicians are uncomfortable with the idea of using one of these blood tests when they have a CT scan right down the bay. And so these biomarkers might potentially be more useful in resource-scarce areas or in areas where you're triaging someone. So for example, at the field level, to triage whether or not to bring someone to the emergency room for now until we end up basically providing some additional cover for our emergency medicine colleagues if and when they decide to use these biomarkers. So neuro-specific enolase, then, is one that's less frequently talked about. And I think that's in part because it really is only telling us about mostly for hypoxic and ischemic-type injuries. It's less useful for brain injury where you're talking about a traumatic brain injury. Neurofilament light is something that's been very prominently studied in the neurodegenerative long-term effects of neurotrauma space because it's looking at neuron damage. And this is one of those biomarkers that, in particular, might be informative when we're talking about the late effects of brain injury, specifically Alzheimer's or other dementing processes like chronic traumatic encephalopathy or CTE. The problem, then, with that is inherent to the fact that it helps pick up these neurodegenerative processes is that it's not specific to brain injury-related neurodegenerative processes. It's just telling us that neurons have gotten injured. And so that might not be particularly useful if we're trying to isolate, specifically, brain injury pathology. It might be very helpful for us to help identify general pathology, though. And then we have p-tau. So tau, I have a cartoon a little bit later in the deck that shows us what tau is and what phosphorylated tau is. But this helps give us information about diseased and dying neurons. And again, it's particularly useful in neurodegenerative processes because it is a hallmark of multiple, the most frequent of which is Alzheimer's disease, but other processes as well. So when we look at these biomarkers, and so this is from the CARE Consortium. This is a study looking at four different biomarkers, a little hard to see there. But basically, the only biomarker that, this is in collegiate athletes, 77 collegiate athletes, the only biomarker that had significant changes from immediately after the injury to both 24 hours later and to when the person's asymptomatic and to after they returned to play was tau. But it did this paradoxical thing where it dropped. So what you see, the first two time points are baseline and immediately after the injury and then at 24 hours it has a substantial drop and then it starts to go back to baseline. Whereas these other biomarkers that you see here, they're all increasing after the brain injury and then slowly going back to their baseline, but it's not significantly, but at least they're doing what we'd expect them to do. So why is it dropping? What's been posited and what I think is likely happening is that you've got tau in a lot of cells in your body and that when you exercise, you end up, you might release some plasma tau. So we don't know if this blood-based tau is coming from, is neuronally derived versus derived from the periphery, from the periphery. And so the problem then is that, what's one of the things we tell all of our concussed athletes to do is to not get hit in the head again, not go back and practice. And so they might have this drop, not because it's reflective of a concussion, but it's reflective of the treatment for a concussion because it's a diagnosed concussion. And so that might be part of the reason why we see this. And then this is a follow-up study that also showed that similar drop in this case, the tau is depicted in slide D, in panel D, which you can see that drop after the brain injury. So what is the tau then? So this is a cartoon of a neuron. In the upper left, there's a healthy neuron. You can see the axons transected and a microtubule is blown up. And that microtubule, I think of it as like the support structure, the scaffolding that supports that beautiful complex site architecture of the neuron. And if that's the scaffolding, then depicted in purple here are these little filaments, that's the tau. And the tau is kind of acts like the nails that support the scaffolding. So when you have multiple neurodegenerative processes can basically have a phosphate group attached to that tau, and when that happens, the tau bends in shape, so basically the nail gets kinked. And so that's what's depicted in this bottom, the disease neuron here. And when that happens, it'd be obviously a problem if you lost some nails in your scaffolding. But the issue is that that phosphorylated tau, that P tau, can induce the normal tau that's around it to also bend, change in shape, and fall out of the structure, and then they aggregate together. So that becomes a progressive process within that neuron, and those neurons are in fact called neurofibrillary tangles, to reflect the fact that they're diseased and dying. That again would be a problem for that neuron, but in vitro there's been multiple studies that have shown that neurofibrillary tangles can induce neighboring neurons to also have their tau phosphorylate, and that way these neurodegenerative diseases like Alzheimer's are progressive with time. So why did I dive into tau a little bit more? Well, this is a study that we looked at looking at individuals who played in the NFL compared to collegiate football players, compared to athletic controls, non-contact sport controls. And we did find some changes in neuroinflammatory markers in the CSF of these individuals that were related to neurobehavioral dysregulation. And that's potentially related to multiple different processes, because neuroinflammation can precede neurodegenerative disease, but it can also precede a whole lot of other problems with your brain. But what I wanted to highlight here in our study is that although you see on the x-axis the CSF neuroinflammation, on the y-axis the neurobehavioral dysregulation, there's a whole lot of overlap. So if you have a single patient in front of you, and if you have this dot in front of you, you don't know whether or not that person has, if this is their IL-6 level, whether they have this much neurobehavioral dysregulation or this much neurobehavioral dysregulation. And so in that way, we see a trend, but the best predictor of whether or not someone's got neurobehavioral dysregulation is to ask them. And so that, I think, is one of the reasons why the biomarkers might be useful more for understanding pathophysiology, but less clinically relevant. And this is another study, then, where we looked at neuroinflammation as depicted in These are individuals who played football and passed away. And in this case, in this particular immunohistochemical stain, the neuroinflammation, the activated microglia are stained red, and that tau neurofibrillary tangles are stained green. And we can see co-localization, both in terms of region and in specific cells, of neuroinflammation and neurodegenerative disease. But the point is that none of these biomarkers are particularly specific or sensitive in a single case. MicroRNAs are really exciting. This is something that, until I talked to one of the researchers in this space, I didn't think about it, but our oropharynx is innervated by so many cranial nerves, and that might actually provide a direct communication between our brain and our oropharynx, and that could potentially be measured through saliva. And in fact, some studies have indicated that there's a high overlap, a concordance, between what we pick up in our brain and what is in our saliva, and we can potentially identify it looking at saliva samples. So for multiple studies that we do, we're pulling up saliva samples as well. But in this case, a group out in Pennsylvania identified some changes in microRNA, both immediately after a brain injury and then up to two weeks later. So this could also potentially serve as a supplementary tool identifying individuals with brain injury. I'll talk about some other additional biomarkers. So there's some stuff looking at the pupil, and there's stuff looking at ocular motor tracking that have potentially identified concussion. But again, I don't think any of this is ready for prime time. There's all of the advanced neuroimaging, and so obviously CT scan, not particularly useful for mild traumatic brain injury, but much more useful for identifying more severe brain injuries. MRI also has some utility, but I think that I'll talk about some of these more advanced techniques that show some potential promise. Volumetric analysis isn't particularly useful when it comes to brain injury. It might be helpful when you're talking about the late effects, the neurodegenerative processes with brain injury, but there's going to be so much overlap and confounding by age. Any of us that have looked at a lot of MRIs know when you see an MRI, you can recognize what we consider an age-appropriate 60- or 70-year-old's level of atrophy compared to a 30-year-old. And so if you're trying to then track neurodegenerative processes on top of that, you need to basically have a pretty keen eye or a model that adjusts for the individual's age before you can make any kind of assessment. And you also don't know whether that's brain injury-induced changes or changes related to other neurodegenerative processes. Susceptibility-weighted imaging is particularly useful for evaluation of microhemorrhages, and so that's what's actually depicted with these arrows here. But I actually have this series of slides here of an individual, a 34-year-old woman who was an unrestrained passenger in the backseat of a car. And CT scan for her didn't show much of anything. But then when they did susceptibility-weighted imaging for her, they were able to identify some area, some foci that were suggestive of microhemorrhages. And then actually it was flare imaging, which is depicted here in MRI, that helped identify these white matter hyperintensities, which were reflective of microvascular injury. And I think it might be useful just for a second to talk about what we're seeing in these flares. So we all know that brain injury, that the brain tissue has the consistency similar to jello in terms of its characteristic properties, right? And if you had a bowl of jello and you were to hit it, it would jiggle and you look at it afterward and you wouldn't necessarily be able to tell that you hit it. But the microvasculature has a different shear and strain properties. It's stiffer. And so now if you imagine that same bowl of jello, but you were to put a bunch of uncooked spaghetti in it, and then you were to hit it, if you look at it afterward, you might see small cracks in the jello around the spaghetti. Because when you hit it, the jello moves a little differently than the spaghetti's moving. And that's similar to what we think is happening in multiple, we've shown in multiple studies, particularly in our football players, that you have microvascular damage that increases in a dose response relationship to the cumulative number of, the cumulative force of head impacts that an athlete experiences. And so that's likely why, after a brain injury, we might be seeing some of these flare changes. And that's what's highlighted by those white spots in the gray matter of the, I'm sorry, the white matter of the brain. Concussion tensor imaging also shows potential promise, but there's been some studies that have followed athletes over the course of a football season and shown some changes in fractional anisotropy to corpus callosum in football players and rugby players. But that occurred independent of whether they had concussions, diagnosed injuries. And that gets back to this idea before that we need to be talking about these subclinical traumatic brain injuries associated with non-concussive impacts. This is a study that we looked at NFL players and controls, and we did some high-definition fiber tracking. And you can see that there's more fraying of fibers that go through the corpus callosum of the NFL player in orange compared to the control, particularly posteriorly. There's also a MRI technique called NADI, which evaluates intracellular and extracellular free water. This has been potentially implicated in identification of concussion acutely, but I think the data is still mixed. FMR has also been looked at, particularly resting state FMR. It allows for, you have the spatial resolution of MRI, so you get a really good understanding of the neuroanatomical distribution and where problems might be. And some studies have shown that players who get more concussions, athletes who get more concussions have changes in FMR that, particularly in working memory tasks, bold signal changes. So that might be a tool, possibly, but it's expensive and difficult to obtain clinically. Arterial spin labeling is a quantitative measure of cerebral blood flow, and so it's similar to FMR in that it's ultimately tracking brain neuronal activation based on blood flow. But the problem with ASL and FMR is that because it's based on the idea that active brain tissue is able to get the vasculature to divert blood to meet its metabolic needs, a brain-injured brain might have different abilities to divert blood flow to regulate the cerebrovasculature. And so it might not be as clear an indicator of areas of the brain that are more or less active because it's an injured brain. And SPECT is something that I wanted to talk about because it's something that's particularly popular with some specific clinics. And many of these clinics offer individuals to get a SPECT scan after a host of neurologic injuries or mental health problems or any different indication. And then they'll offer nutraceuticals and vitamins that will help cure your SPECT scan. I've never once had a patient in 15 years of seeing these, 16 years of seeing these scans, people from these clinics. I've never once had a single patient who had a baseline normal SPECT scan. Every single thing, there's a problem there, and if you just take this vitamin, it'll help you. So I think that there are use cases for it, but I think that it's been abused. MEG looks at the magnetic signals in the brain and relates those underlying electrical currents to areas of the brain that are active. So it might provide a more accurate insight into what's going on with neural tissue as opposed to FMR, which is looking at the blood flow. So that's at least potentially something useful, and it might give us some information about connectivity, but there isn't a lot of its use in brain injury at this point, or validation of brain injury. And last, the imaging modalities I'll talk about is magnetic resonance spectroscopy. This is kind of like a brain biopsy. I've started ordering it in some of my athletes, and it's hard to get paid for, but I think that, in particular, when I'm concerned about neurodegenerative processes, it provides some additional insight into what's going on inside the brain. So next, then, I wanted to talk about this study that looked at flare in our football players, and we found that there was a dose-response relationship between flare, I alluded to this study earlier, between white matter hyperintensities and flare, and the duration of football play. But again, you have this problem where there's, if you look for a specific level of flare, it's not telling you that this individual, whether they had this much duration of exposure versus this much duration of exposure. So it's more useful in the aggregate than in the individual sense. And I'll close with talking about PET imaging. So this was a landmark study by some of my colleagues in 2019 published in the New England Journal looking at 26 former NFL players for a specific PET ligand that binds to phosphorylated tau that's meant to be diagnostic of neurodegenerative processes. And this one showed that there was higher uptake of that PET ligand in NFL players than in the controls. And so our group at Harvard then tried to replicate that study, also using 26 NFL players and the same number of controls, and we weren't able to find differences in NFL players based in the controls. So what's different? Well, our NFL players were sampled from the general NFL community, age match, everything was the same there. But my colleagues at Boston University, their NFL players were required to be symptomatic before they were included. And so it's entirely possible that they might have more tau burden in their brain and that the ligand might not be good at picking up lower levels of tau burden in the brain. And in fact, that's actually been borne out in the Alzheimer's literature as well. When we've looked at, when groups at UCSF in particular, but other groups have looked at individuals with pathologic confirmation, it appears that this particular ligand really is only binding when there's a lot of tau. So it's not particularly useful unless someone's demented or got problems. And in that case, you can talk to them, they've got problems, right? So you need the ligand to tell you that. And so then actually, I worked with the team at BU in this project, so instead of 26 football players, it was 104 professional football players, 58 college players, and 56 controls. And when we had this larger data set of individuals, some with symptoms and some without symptoms, we were in fact able to find, to replicate that finding of the New England Journal paper study where there were some differences, but they do appear to be associated with severity of symptoms. So I wanted to thank you for that, and now we're open for any questions. Thanks. Give it up for Dan! Questions, comments, ideas? Tell us why we're wrong. All right. Is anybody using imaging, fluid biomarkers, electrophys for any of your clinical decision-making? And any type of, well, in mild to big? Bring it on, what do you got? I was yelled at earlier and told that, and asked if we could have people go to the mics. Is there a mic somewhere? I need a guy with a mic. Here we go. There's a mic right here. So, we use electrophysiology at the University of Colorado. What? About seven or eight years ago. Coach didn't like the results, so he. didn't use it. But the specificity and basically usefulness was spot on. But we used P300 evoked responses. And we had very small variants. We tested everybody in the football up in the amplitude of way over 40%, more like 60%. And when they're ready to go back, 70% of them improved back to baseline. 30% didn't, and the 30% ended up getting some other. on a regular basis, not for football, but for all my cognitive. Are you using it to guide further treatment, using it to inform them, or just for the hell of it? Why are you using it? We're using it to guide treatment because you don't know when a patient gets to a plateau. And how labor-intensive is it in your setting to get it you know we because that's gonna be a question Can they do it and they're all freaking easy to use is ridiculous because technology is improved crazy So we had a kid who was a pro hockey player. I Looked up at the scoreboard and you can see the time marker, you know, it's like, you know for this is not a joke It's 440. We brought him in the locker room because there's a follow-up did the test on him could see that he was back to baseline And he was back on the ice and it was a Total of 10 minutes. I mean this is fast stuff and you know text can do it We had a student assistants at University of Colorado do it anyway Great comment and please feel free to to stay after those the folks can talk to you about that I know you we're trying to get that use more. Thanks Frank Other comments questions I Thank you both of you for the awesome talk I work for dr. Sifu, so But yeah, whoever else wants to answer. So I'm a sports medicine physician and Work with athletes all day every day and I think my question for you is My athletes get better without any of these studies or any of these biomarkers. Am I doing this wrong? Okay, I'm gonna let you go first because we work together but I've got yeah Nothing Mary's done is ever wrong. She's the best Mary called Wow Yeah, I mean so basically I would say absolutely not because I see all I mean My clinical practice is I work with the brain and body program So it's NFL players and then I work at home base, which is special operators So individuals a lot of head impacts and for the most part I Because I have a lot of resources to be able to order any biomarkers I want I'll get some for them, but I'm really only getting them to tell them things that I already know So for example, oh this these imaging changes suggests that you might have gotten a lot of head impacts I knew that already you told me that Tuesday, right? So There's in the actual clinical management and diagnosis. It doesn't change anything about what I'm doing for them now the reason that I'll sometimes get some of these images and Imaging in particular and show it to them and that I find it valuable is that if I'm we're physiatrists, right? and for us what matters most is our ultimate function and We know that if I had a pill that was as good as exercise is for for Alzheimer's disease or Parkinson's disease That'd be a billion-dollar pill, right? I Can't convince them more definitively that there are problems associated with Hyperlipidemia hypertension Diabetes more so than showing them white matter hyperintensities in their brain and say some of these might be related to head impacts But I know what's gonna make them worse these other factors and then I can pull up imaging of somebody who has a lot worse White matter hyperintensities and that I think that so it's not changing the clinical practice, but it's changing the the messaging I think it makes it more impactful in addition to that. I'd say that that dr Caldwell is an expert at what she does like if I believe her if she says that someone's cleared There are there are certainly folks that don't that don't have that level of expertise because they don't have the time the training whatever it Is they may be in another country maybe in rural and they might not even understand how to go about assessing High-level balance or coordination, right? So for those folks, it may be a nice way to kind of confirm and then actually to teach them This is a person who still has got some inflammation whether it's a p300 whether it's a fluid So that's that might be an area, you know Because there's there's enough studies in the back pain area that says that people with a lot of skills mostly PTs I might add it the literature says but Who examine someone do a really good job and they're finding stuff. But what about the rest of us? All right, I'll include myself What if I don't know how to diagnose that it's it's useful to learn Residents, but it's also useful to confirm it it were if you're again, you don't have a PM and our doc There's only what ten ten thousand of us. There's a lot of places to be in a lot of other countries So that might be one area right to add to it but but sadly the future and I hate when old people tell me this because I'm an old person is The future is going to be these kind of objective measures because I've been hearing that since a resident We're kind of close to it now and we'll be able to use it but it's going to be an adjuvant All right, it's gonna be an add-on But if you don't have the experience, you don't see the volume someone else doesn't have that we need these things So that that's gonna be the first step I think Thanks, Mary other comments I was just wondering besides like subsymptom Sure, yeah, so I'm very really curious to hear what you're doing because there's I think different practices all over But I actually don't do some symptom exercise. I I Think that that was something that we you know, what 15 years ago We're training people to do but I think that I mean if someone's headache gets a little worse when they're on a stationary bike Does that tell me anything what's going on neurologically for them? I don't think so And so I actually encourage athletic basically as long as an individual is not going to get hit in the head again Then to get out there and do things that are going to increase cerebral perfusion So like stationary cycling is something that I recommend a lot Swimming is something that I recommend also, you know, basically activities are not gonna get hit in the head but I I think that There's a There's been a lot of literature that supported the nocebo effect when it comes to concussion management and this idea that you tell individuals that they have a brain injury and that they can't do specific activities and That that might actually potentially do some harm as well. So we kind of need to balance both That's right. We're fortunate to have John Letty out at our place two weeks ago for a great lecture And you know John really is the foremost exercise following concussion research He's not a PM in our docks. We don't hold it against him I made him an honorary one when he visited with us great guy, John But but you know John's like look, you know if they can tolerate their headache if it's a you know If it's a nine out of ten no stop and you need to look at doing something soft tissue work Find some other cause you may have missed the problem. It's their neck not not their head But he said push through it. I push it's fine to have a headache headaches are overrated All right, like they're not markers of a lot of things All right, particularly we're talking about young athletes for the most part have been evaluated and are exercising the other piece I would add is I love the opportunity after a concussion or any kind of injury to use it to try to help to Shape the person's overall life if possible not not preaching to them, you know all wellness But like well have you ever thought about this a different way to as Jess just said maybe sleep or being a being a more Supportive nutrition regimen. I won't say diet nutrition regimen, you know be on a you know in a program where you're managing some of that anger Anger is really good in the military and in sports, but not for recovery. So that may be an opportunity, but but I absolutely Believe that symptoms are there to guide us Don't be afraid if it's okay, you know, no pain no gain probably is overrated but something along that line But totally agree with you Dan and if you don't know John Lettie's work or watch one of his videos He is the bomb real world and nothing. He says isn't based by his data It's crazy how good it is. But again long story short He's like get them back to exercise get him on you know whether it's a bike whether it's walking get him back to their sport or to their to their exercise and Monitor symptoms don't overdo it downplay downplay, you know, but great question good answers other We're making Dan work today My steps in your towels through the roof dude, just as walking. That's great. Just further to that point the exercise recommendations on a practical note is a 30% or 50% chance that you're going to get sick rated a 5 out of 10 subjectively, and then the person goes and hits the treadmill, for example. As long as it only goes to a 7 out of 10, that's considered... 30% above where they're at. 30% above where they're at. Thank you. Just a quick question in terms of concussion management, because I still struggle with the distinction between the cervicogenic, the vestibular, and the, yeah, cervicogenic, vestibular, and I guess the combined oculomotor sort of areas. If you could, from all the different studies that have taken place, is there anything that you can see down the road helping in terms of aiding the clinician, like the physician, to distinguish between the ideology of, say, a neck problem versus a visual center problem versus a cerebellar problem? Because it takes a lot of time to tease out those nuances, and sure, you can send them on to these different clinicians, but it's tricky. Yeah, that's a great question. I mean, I'll take a beginning step. You know, the VOMS is the gold standard in the concussion rule, and I don't understand how that became a gold standard. It just isn't that useful. It's something, but that's where actually a good biomarker is needed, is looking at the differences. I'm thinking 90% of it is related to the neck, and it's not ocular vestibular. It's due to immobilization of the neck, whether due from fear or from pain, whether actually due to trauma and injury. But just as we answered before, if you've got the world's best cervicogenic PT or sports PT, don't overthink it. Get them there. But if you don't, then we need to talk about, do we need more objective measurements? And, you know, the Balance Master or computerized posterography will give you a lot of good information. It's typically pretty available, and just about anybody can test on it. It can help a little bit in terms of looking at the vestibular versus ocular motor, but really, it's a physical exam. Right now, to me, it's limited to physical. There isn't a rapid assessment tool. I understand that you're aware of one specifically. No, I completely agree with that, actually. But I wanted to ask you a question also. So, yeah, the 30% symptom increase threshold is something that, you know, we talk about. We quote a lot. Have you had a lot of experience, like a lot of positive experience, you know, conveying that? I'll speak from my experiences. Basically, whenever I get like too bogged down in the numbers, I feel like I lose people sometimes. And I get them to kind of focus. They end up kind of focusing on the, like, am I a six now, or am I a seven? Or, so I don't know if you can maybe speak to your experience with that. Just get ahead of this and say I don't have an answer. But I think your question, in my view, from a practice perspective, speaks to the conundrum we face as clinicians where we're trying to get through our day. And the patients that we're seeing from my physiatry practice are more of the chronic patients that have a greater breadth of problems. And so, in essence, there's more hand-holding that goes on. There's more validation and education. And more often than not, the individuals that I see have the psychiatric and psychological factors. So basically, in that group, you need to double down on the educational component early on and to indicate the importance of essentially pushing through symptoms. I don't find my patients ever receive the, well, sometimes they receive the remark, suck it up, buttercup, well. But the truth is that's how we get through things sometimes. Like, you have to push through symptoms in order to move that baseline further. And that's what I tell patients, that it's a physiologic disruption. What I find challenging with these slides is that we're telling patients, hey, this is not a structural injury. This is after 30 days. The calcium influx issue and the ATP drop is no longer an issue. This is more of a physiologic disruption that's troubleshooted through different regions. But at the same time, we're seeing, okay, well, there's abnormal tau in the blood and all these other biomarkers and there are structural issues. And you showed me a picture of the Olympic system and the NFL players. And it's like, okay, well, which one is it? Is it not a structural problem or is it? It seems to me like it is a structural issue. It's just on a micro scale. And we're trying to mitigate the implications of that. So sorry, I kind of spun away from your question. But certainly, yeah, just telling people to push through it is basically what I'm saying. And my counsel is close your eyes. So the visual system accounts for about 80% of your brain's ATP requirements. So instead of being in a light room where you're looking around at people and you're trying to exercise and you're hoping for validation on a treadmill, get them on the exercise bike, close your eyes, put on quiet music, darken the lights, and go slowly and then work your way up. And then stick with that. And if you get a little lightheaded, you get dizzy, you sweat too much, that's okay. Just keep going. And then in addition, the meditative strategies afterwards, lay down maybe some glutathione under the tongue, wild salmon and broccoli twice per week, all the extra stuff kind of plays into it. And overall, you'll feel better over time. Yeah, definitely empowering them with positive information and giving them specifics because they're looking to you as a trusted, quote, expert on it. 100% agree. And those practical statements you just made, I mean, it's right on. I think day in is the future. And no, in five years, this is going to be what we're practicing. But don't confuse them with this knowledge yet, because it's not ready for prime time. That's kind of this takeaway. What you've just said is prime time right now. I love that. So you need to be doing this talk next year, because that's really good stuff. That was really insightful. In fact, that contradiction that you point out, where our understanding of our current management of concussion and where I think we're going, that contradiction is, I think, the exact reason why I thought this would be an interesting talk, because we can kind of explore both of those. So thank you for that comment. I want to thank everybody for your attendance. It's great. Thanks for being at the Academy meeting. I hope you've learned something. Feel free to reach out to either of us. We're on the, you know, you can find our emails easily. They're on the slides as well. And if you've got further comments and questions, please send them to us. So thanks, everybody. Have a great rest of the day.

biomarkers

traumatic brain injury

TBI

Dr. Dave Sifu

Dr. Dan

neuroimaging

military

veterans

clinical evaluation

chronic inflammation

rehabilitation