- One subject that we haven't talked about on this podcast previously, but is of tremendous interest to people is traumatic brain injury or concussion, even mild concussion. And before we were recording today, we were talking about football, but just wanna remind people that football is just one instance of an opportunity to get a concussion or traumatic brain injury.

Most traumatic brain injury and concussion is not due to football. It just gets a lot of the attention, but you've got bicycle accidents, car accidents, playground accidents. Maybe you could list off a few more, but how common is TBI in concussion? And maybe you could just perhaps list out some of the other situations where you see a lot of this, that it's a bit more cryptic that people wouldn't necessarily think that sport or that population gets TBI, but they do.

- Yeah, I think concussion is much more prevalent than we realize, and the numbers have gone up and up, not because it's becoming more common, it's just that it's becoming more recognized. And I think we underestimated and trivialized sort of what a concussion is, that it's just something that is, you're gonna recover from it.

I mean, still the old school thinking by a lot of neurologists is that everyone gets better within a couple of months. Just wait it out and you'll get better. That's just the normal time course of concussion. But as we've studied it more, we realized that there's actually quite a large percentage of people who a year out, they're still suffering problems.

They still feel like they're not mentally clear and they still are sensitive to light and they still feel a little dizzy. And just a host of symptoms that just one year later, after a concussion where they didn't even lose consciousness, that's something that they may not have even talked to their doctor about is lingering.

And so it's a real, we call this persistent post-concussion syndrome and that's the most worrisome to me because it is true that most concussions will recover. Luckily the brain is incredibly resilient, incredibly plastic and it will heal itself. But there are a lot of patients where it just persists and those are the most worrisome to me because we don't have very good interventions to try and help that.

And I don't think we take these patients very seriously when they're complaining of something that seems very vague and not very specific to most doctors. - What do you tell a patient who comes in and clearly had a concussion, mild or severe concussion, maybe car accident, maybe a sports injury, maybe they were knocked out cold, maybe not, but they're having some headaches, some photophobia, sensitivity to light, just feeling not right.

I've had a couple of these, unfortunately, and you just feel off, you don't feel quite right. And some of that manifests as focus issues. This was some years ago, I like to think I'm through it. I've had scans and I'm good, so thank goodness. But what do you tell them besides don't get another one?

- Yeah, well, first of all, I explain what a concussion is. What I found in neurology, a lot of what patients wanna know is just, they just wanna understand their problem, not walking in expecting a cure, just understanding what it is, having someone understand what happened to them is very helpful and comforting.

So what we mean by concussion, and in the clinical world, we use mild traumatic brain injury kind of synonymously with concussion. It basically is a tearing of axons. The brain cells have these long fibers that communicate with each other and they're called axons. And when the brain violently moves forward and backwards, if you're in a car accident and you have your seatbelt on and you suddenly hit, you go from 50 to zero, your head violently goes forward and violently goes backwards.

And that angular force actually tears and stretches axons in the brain. So if you've had a concussion, you have torn some axons. I mean, luckily we have billions of them. And so if you tear a couple of thousand, you will recover, but you have torn axons. It's a real neurological, it's a real brain injury, even if you haven't lost consciousness and you've only had symptoms for a couple of days.

But there's a correlation. The longer you've lost consciousness and the longer your symptoms last, the more axons you've torn. There's kind of a direct relationship between the two. So the mechanism is these torn axons. So now, nerves don't communicate with each other and the brain, different brain regions are not communicating with each other.

So, and it turns out the most common place for axons to tear is in the frontal lobes. And so now we talked about all these things that the frontal lobes do to orchestrate the rest of the brain. Well, it doesn't, it has some injured pathways. And that's why a lot of the symptoms that patients have are these kind of mild executive symptoms.

This mental fogginess that they're describing is this ability, just this inability to get things done. They don't lose knowledge of who they, they don't forget their name or forget where they live or lose memories from the past or anything like that. But they just, they don't officially get things done as well as they used to.

And it only takes a little bit of a drop, right? People think you have to have a big drop in performance to have it have a real life impact. Just a 1% drop and you're having a hard time doing your podcast or teaching a lecture or whatever you might do.

- A 1% drop sounds like a frighteningly small change required to negatively impact life. So how about a poor night's sleep? I mean, what kind of drop in prefrontal cortical function are we looking at from, let's say, I normally get seven or eight hours or six to eight hours and I suddenly only get three or four.

Are we talking a significant detriment? - I do think so. I do think that, yeah, that it is significant, this poor night's sleep. And we all notice that. I mean, it's very obvious. I mean, and you know, it's hard to sort of quantify. I'm a baseball fan, so I can quantify it.

Like if you think about it in a pitcher and how fast they throw, you know, a small drop for them, someone who's throwing a hundred miles an hour, just a small drop turns them, you know, from really elite to someone mediocre. Maybe it's more of a 10% drop, but it's still relatively small drop can have a huge impact.

I think people think that just because you're a little bit off, that's not gonna, that's not a big deal. You kind of work through it. And that's what most doctors say. You just plow through it, just work your way through it. You're gonna get better. And as opposed to saying, yeah, you really had a brain injury.

This is what happened. We need to rehabilitate you. Just like we would do if you tore your anterior cruciate ligament. I don't know why tearing your cruciate ligament or your Achilles tendon gets more interest than tearing axons in your brain. It's amazing to me that there's more emphasis on orthopedic injuries than brain injuries.

- Yeah, I don't know why that is either. I think the brain is mysterious enough that most people and many clinicians just kind of back away with hands raised. But if you are in the field of neurology or psychiatry, I suppose that then one has officially signed on to try and resolve these matters.

So for somebody that has a traumatic brain injury or low-level concussion, excuse me, would part of the primary advice be to try and get one's sleep as good as possible? Given that sleep deprivation can compound traumatic brain injury-induced deficits in working memory. And who knows? Maybe a good portion of the deficits in working memory due to traumatic brain injury and concussion is because of the sleep deprivation that it can cause.

So it can get circular. - Not only that, but one of the most common symptoms that my patients with concussion have is their sleep is disruptive. And that's true in neurology. It's fascinating. Almost every neurological disorder, my patients complain of their sleep. And I started asking, not a lot of neurologists ask you how you sleep.

But I remember back from my residency, one of the first things my attending would do when we got to the ward is, "How'd you sleep last night?" And it's just across the board. Patients are not falling asleep. They're not staying asleep. We still don't understand why just brain injury does that.

So almost every concussion patient says, "I'm not sleeping well," which then compounds the problem. So optimizing sleep, obviously, optimizing nutrition. There's a question about activity. It used to be that we used to recommend, you had a concussion, you should don't go to work, just take it easy for a while.

Don't exercise. - Keep the blood strong. - But now it's the idea is that you should really get up and moving. You gotta do what you can tolerate. You don't wanna give yourself more of a headache or more light sensitivity. But as much as you can tolerate is the thought these days about sort of promoting recovery and then really getting your brain back working.

I think a lot of my patients, they're off from work for a couple of weeks and they feel fine and they think they're pretty much normal. And then the first day of work is a complete disaster because until you actually test it in real life, you don't know what kind of troubles you have.

So I don't recommend going back full steam, but I do recommend going back, trying to build up these skills again. And then I think we need to develop therapies that people will use. Things like goal management training, which involves a therapist and health insurance doesn't pay for this. So 99% of my patients don't get any help by any kind of intervention, unfortunately.

But now we talked about technology, things like Brain HQ. Do you know about Brain HQ? So Mike Merzenich, which I know you've talked about with Eddie, developed a company called Posit Science where it developed these brain training games that can help improve specific cognitive functions. And they're very easy to do because they're online and there's science behind them and you can do them.

So in that way, you don't have a therapist in your room, but you can online sort of do these sort of things that are targeting specific mechanisms to try to improve the kind of things that we think are impaired by concussion. And I'd like to see more patients get started on some of those things.

Importantly, if you go on the web and just say I'll do brain training, you'll be overwhelmed with things and you don't know what works and what doesn't work. - Yeah, I think the work that Merzenich and colleagues have done, and we'll provide a link to that. I don't have any financial stake in his work or products trainings that is, but I will say I think Mike's work has been tremendous.

I mean, he is so far ahead of the curve. (upbeat music) (upbeat music) (upbeat music)