More Than Meets the Eye: Troubleshooting Visual Symptoms After Concussion with Dr. Paul Brewer | E21

Dr. Brewer brings his expertise as a neuro-optometrist to explain how visual processing problems are often overlooked in concussion recovery despite causing significant symptoms. He shares insights on integrating visual, vestibular, and proprioceptive systems to create lasting improvements for patients with post-concussion syndrome.

• 20/20 vision only measures clarity, not eye tracking or binocular function
• Many post-concussion symptoms stem from poor integration between sensory systems
• Light sensitivity can come from multiple causes including dry eyes
• Cervical (neck) issues can cause visual problems and vice versa
• Too many sensory errors overwhelm the cerebellum, causing fatigue and emotional dysregulation
• Standard vision therapy exercises can worsen symptoms if they don't address the right problems
• Peripheral vision processing often becomes impaired after concussion
• The brain's ability to filter information is compromised, creating sensory overload
• Integrating multiple sensory systems creates more significant improvement than treating each in isolation

You can find Dr. Brewer at Diverge Performance in Boise, Idaho, or online at divergeperformance.com.

Instagram: @divergeperformance

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Chapters

• 0:00 Visual-Vestibular Integration in Concussion
• 7:22 Dr. Brewer's Path to Neuro-Optometry
• 13:19 Understanding Visual Acuity vs. Eye Function
• 18:31 Eye Movements and Binocular Vision Explained
• 23:49 Vision, Vestibular, and Proprioceptive Systems Integration
• 29:12 Understanding the Cervical Ocular Reflex
• 36:40 Light Sensitivity: Causes and Assessment
• 44:15 Peripheral Vision Processing After Concussion
• 51:27 Finding Specialized Care for Vision Issues
• 59:47 Closing Thoughts and Contact Information

Transcript

Dr. Paul Brewer: 1:10

Yeah, but, and another thing too, is if you have too many errors, it's like if the vestibular system is pulling the body one way the vision is pulling the body, another way you get this push and pull all day long, right? So it's better to have them work together than doing this all day long, which can make the brain really tired and make you fatigued.

Dr. Ayla Wolf: 1:32

Welcome to Life after impact, the concussion recovery Podcast. I'm Dr Ayla Wolf, and I will be hosting today's episode where we help you navigate the often confusing, frustrating and overwhelming journey of concussion and brain injury recovery. This podcast is your go to resource for actionable information, whether you're dealing with a recent concussion, struggling with post concussion syndrome, or just feeling stuck in your healing process. In each episode, we dive deep into the symptoms, testing treatments and neurological insights that can help you move forward with clarity and confidence. We bring you leading experts in the world of brain health, functional neurology and rehabilitation to share their wisdom and strategies. So if you're feeling lost, hopeless or like no one understands what you're going through, know that you are not alone. This podcast can be your guide and partner in recovery, helping you build a better life after impact. All right, Dr Brewer, welcome to life after impact, the concussion recovery Podcast. I'm so excited to have you on here. You are an expert in working with people with concussions from an optometry lens, and you are really on the cutting edge of combining a lot of vestibular and sensory integration into the vision therapy work that you do. So I'm so excited to be able to pick your brain and have you share some insights into the work that you do and the clinical experience that you have in working with people with post concussion syndrome. So welcome to the show. Thank you. Yeah, you have a practice in Idaho. You're originally from Hawaii. Correct, correct,

Dr. Paul Brewer: 3:15

yeah, I'm originally from Hawaii. My roots are in the islands, and I met my wife in Hawaii. And my wife is actually from Idaho, so we moved up here to be closer to her family, which, that's, you know, starting a practice up in Idaho, in Boise, yeah,

Dr. Ayla Wolf: 3:30

yeah. Well, it's a beautiful area.

Dr. Paul Brewer: 3:33

Have you been?

Dr. Ayla Wolf: 3:34

Yeah? I, well, I lived in Oregon, so I was very close, and so I got to, you know, make some, make some quick little trips here and there. So, yeah, a very beautiful area. I've been to Joseph Oregon, which is like, in the south or northeast corner of the state, and I feel like that's just like this little hidden gem in this country that not many people know about.

Dr. Paul Brewer: 3:59

I've been through there. We were up in like Moscow, or whatever, for my daughter's gymnastics me, and then when we drove down from there, we passed through Joseph,

Dr. Ayla Wolf: 4:10

yeah, yeah, such a great little part of the country. So tell me a little bit about how you ended up specializing in post concussion syndrome, or people with concussions, and maybe some of the kind of unique things that you bring to your practice in that regard.

Dr. Paul Brewer: 4:28

That's good question. So, like, I don't have this, like, crazy, cool story, like, I came out of my mom's belly and, like, literally, I started loving concussions. You know, like, every doctor seems to have that story of, like, oh yeah, since I was a kid, I like this and that, right? I mean, it was never even on my mind, actually, like, I mean, growing up in Hawaii, I played a lot of sports. I actually had a lot of concussions, but it never dawned on me that, oh yeah, you could do something for concussion. I mean, it had a ton of undiagnosed concussions. Fact, when I speak on concussions, I show this video of me when I'm a teenager. I'm skateboarding on the seal really fast. Get some speed wobbles. I bounce off my board, hit the telephone pole, bounce off the ground, hit my head, and like, you know, I mean, so I'm not, like, a stranger to concussions, so I but I also knew how it at the time, I didn't know, but now I do know how much it actually affected my performance. My story was a little different than a lot of people that have concussions. A lot of people, like, when they get concussions, they get messed up. They mean their life falls apart. In my case, I mean, I always had deficits. I didn't know I was I had, but I was good compensator. So a lot of people can compensate, but does that mean that they're actually it's actually good for them? So I compensated really well. I mean, I played four sports in high school. We did I did a sport in college, and, you know, I was a biochem major, had pretty much straight A's. That was one of the ones where I was flying under the radar. But I didn't realize how much work I had to put into studying and everything else. I just didn't realize. I thought that was just normal. And as I, you know, went into Tom. To school, I learned more about visual rehabilitation, and at the time, you know, they, you know, the diagnose me with convergence insufficiency, which is a pretty common eye condition that can be diagnosed when they have binocular issues. And they're like, Oh yeah, you have this issue. And if you do this therapy, you'll be better. And I remember, in my mind, I was a first year, and I remember, like, all these, like, third years crowding around me because they thought it was really cool that had this you know, thing, you know, convergence insufficiency, which isn't really that big of a thing anyways, but like they, you know, when, when you're in student, anything that you see as abnormal is really cool. And I was getting kind of pissed off because there was telling me all this stuff before they explained it to me. I'm like, Hey, so hold on, guys, what's going on? And they finally said, oh, yeah, you have this issue that's affecting your performance. And I'm like, really? And I've been to the eye doctor every year my life because I had contacts. And I'm like, why didn't the doctor ever tell me this? You know? I'm thinking my head, like, Wait, if I actually did this therapy when I was a teenager, I would have been able to study better, you know? Like, I mean, or I would have been able to do even better or study more efficiently. And this dawn, I'm like, Man, I really wish my doctor told me that. And that's kind of that point in time where I had this passion of learning more about the rehabilitation versus just like glasses and contacts. And that's just, you know, that's important thing too, as well. But it really made me excited about learning about the brain and the neurology of the brain back in my first year of optometry school. I mean, when you go to school, you learn kind of this, like basic, foundational stuff, and you don't really learn a lot of this, like neurology per se, in school. And that's why, like, you know, institutes like the Carrick and others and so forth, you know, they they give these courses post doctorate to be able to put you at a different level. And, you know, I learned a lot in school, don't get me wrong. I mean, I learned a lot about visual rehabilitation, but most of my learning came from after school. But it was that passion I had that like I could actually help other people. I could actually help people recover quicker and perform better, and I had my own story and how it kind of helped me. And in reality, you know, the vision therapy I did in school really helped me, but what brought me to another level is when we started incorporating other sensory integration, like vestibular and and so forth, and that kind of helped me even recover even better. I think I don't even answer, did I even answer the question. I think I totally went on a totally, yeah,

Dr. Ayla Wolf: 8:33

you did. You did. No, I was curious, kind of what, what your interest was, specifically with concussions and vision rehab in that regard was. And yes, you think it's

Dr. Paul Brewer: 8:43

really cool. It really is super cool, like it's it's so cool to see that the brain is plastic. It's so cool to see that we can do things to activate the brain to recover and perform better where, you know, like, 15 years ago even, I mean, not even 15, even more than that, but like, and even now, people are like, Well, you can't do anything with the brain once it's hurt, it's hurt, and it's cool to be able to see that. In fact, I had a patient that I just finished, you know, we just did a few sessions. And, like, literally, for the last like, two years, they've been, they've been to every single doctor, I mean, and in two functional neurologists defense, I mean, they, there was really no one they saw for that here, because they did see, like, they like acupuncturists and chiropractors and so forth. But then it's the same thing as saying, Oh, they saw optometrist in each of our professions, there's different types of specialties and like, so he didn't really see any functional type doctors in any of our professions, right? So they're kind of pushed and pulled to all these different areas. And finally, the doctors like, you know what? You just have to deal with your business. You have to deal with this, you know, like, and so they just live their life, and they, I don't know how even they found me, they found me, whatever, for a reason, maybe a referral, or online, or whatever. And they came in, and we started doing some sessions, and literally, after about like four sessions in, they're like, Oh my gosh. Like, they saw a huge difference their life. They said they were going to make better eye contact with people. They can actually walk outside for long periods of time to be able to, like, enjoy the scenery, versus, like, shutting down and so, like, it was cool to see that so quickly. And I think if I just really just did my own thing, like to say this vision only, it probably would have taken longer, but in integrating all the different parts of the brains and doing different types of therapies really helped them get to a place where they were happier, quicker and more efficient. Yeah, yeah.

Dr. Ayla Wolf: 10:44

And that's, that's amazing, and always such a good feeling when you can, you know, not only like, start to help people, but then actually find ways of doing it really quickly and getting those kind of immediate wins, because that's what encourages people to stay the course and recognize that there is room to improve, which is always giving people that hope is so important for sure. Can you talk a little bit about so. You know, my my experience with so many of the patients that come to see me, when I ask them about who have you been to, who has assessed you? Many of them say, Well, I was having, you know, light sensitivity or blurry vision. I went to my eye doctor, and they told me that my vision was fine. And so we have this kind of difference between visual acuity versus eye movements and how the two eyes are working together. So can you maybe talk about for our listeners, the difference between visual acuity versus eye movement disorders or dysfunction within how the two eyes are are moving or moving and communicating together and why so many of these eye movement disorders are maybe getting missed in a standard exam.

Dr. Paul Brewer: 11:56

For sure, yeah, and in reality, in a stat, in a standard exam, in reality, they doctors should be testing eye movements. They should be testing eye focusing and eye teaming. In some cases, it might be brushed through really quickly. So let's talk about, we'll talk about acuity. We'll talk about eye tracking, eye movements. We'll talk about binocular vision. Then when? Then we'll talk about, like, I'll maybe go over one test on how we do it and why it might be missed. Does that make sense perfect? So the first thing is visual acuity. So like most people think visual acuity as like perfect vision. So when you when you hear 2020 that's the coin term, 2020 you have 2020 vision. And when people say, Oh, I have 2020 vision. In fact, most of my patients say this every single time when they come in, oh, yeah, 2020 vision. I have perfect vision. I'm like, the first thing I usually ask people is, like, what? What is your understanding of 2020 and most people again, will say, Oh, perfect vision, or crystal clear vision, or whatever, right? And in reality, you can have better than perfect vision, because you can have like 2010 vision. So all the numbers refer to as like. The top number 20 refers to looking at the chart from 20 feet away, so the chart will be calibrated at 20 feet. And the bottom number refers to the size of letter. So 2020, is a certain size. 2010 is half the size. 2040 is double the size. So that's all it refers to. Is the clarity of vision. So clarity of vision is that one the first step in the whole visual processing pathway. Now you can have clear vision, or 2020 vision, or even 2010 vision, but have imperfect vision or dysfunctional vision. So I get this a lot from patients. They're like, Oh, yeah, 2020 vision. There's nothing wrong with my vision. In fact, a lot of times they're like, oh, like, one of my things on my questionnaire is about headaches, and they're like, oh, I don't think it's related to vision. I'm like, I just ask him. I'm like, a little snarky about it too. I'm like, I'm like, How do you know it's not related to vision? You know, like, and they kind of sit there, like, thinking they're like, Oh, actually, I don't know, because people just blurt these things out of their mouth all the time, right? Same thing with perfect vision. And in reality, you can have the clear vision, but you might have poor eye tracking or eye movement. So let's talk about eye movements. So there's different types of eye movements. One is, can you keep your eyes fixated? And a lot of people say gaze stability or fixations. But can you keep your eyes just steady on a target? And in reality, you can never keep your eyes fixated on target perfectly, like with no movement, because always eye movements. But even when you have gaze stability, there's all these little micro saccades, what we call them, all these little different movements. And your eyes are constantly moving, because if they don't, then you won't your actually, eyes will get like, your vision will get dark. So it has to constantly move to refresh. They call it photoreceptors in the back of the eye, so that it's to refresh those photoreceptors so they don't like bleach out, or they don't like over activate. So that's fixation. So can you keep your eyes steady on a target? But people that have poor gaze stability could have brain dysfunction or issues with like the cerebellum or other parts of the brain that can cause these issues with keeping your eyes stable. So if you can't keep your eyes stable, what happens to the clarity of vision. If your eyes are all over the place, right, you're going to have blurry vision. So sometimes people will have the perfect prescription, they'll have the perfect pair of glasses. But, like, my vision is kind of blurry. It kind of fluctuates right? So that could be a gaze stability issue, and that usually goes hand in hand with, like, the vestibular system and so forth, where, if you have poor communication between those systems, you might have poor eye tracking or eye focusing, which can cause this fluctuation of the clarity of vision, which causes blurry vision. That's the eye tracking part. But the other part of eye tracking is not only fixation, but there's two other elements, one is saccades, and one is pursuits. So we're not going to go over all the neurology at that. It take too long, but saccades are basically like, can you jump from one spot to the next spot? So can you go from this spot to that spot accurately? So someone that has poor saccades may look at this finger here, and then when you look at that, figure they go way out here. Yeah. Right? So they can't fixate, and they can't saccade or move their eye from one spot to the next. That's another type of eye movement. And the third type of eye movement is pursuits. Can you actually track a moving target smoothly? But there's different types of machines that can obviously test for this. You can do gross testing just by using a target, and that's ways of actually testing to see if the eyes move or not. Again, you can have clear vision but have poor tracking. Another element of vision is eye focusing. It's called accommodation. So eye focusing, there's actually a lens in your eye, so this is your eyeball in the middle of the eye. There's this lens that's like oval shaped, and it acts as a magnifier. So when you're looking far away, that lens is about this shape, and it actually has a power to it. But for this example, we're going to say that power is zero right now. So when you're looking far away, the power is zero. And then when you go up close, when you're looking at your hand or something close up, about arm's length or closer, there's these muscles that automatically contract. It's controlled by the parasympathetic system. Those muscles contract, and the lens changes shape. And when the lens goes like this, it changes the magnification power. So, you know, I have those magnifiers that can magnify things up close. That's what the lens in your eye does, and that's what eye focusing does. So that changes shape. So if you have dysfunction in the neuro and the neural pathways or the muscle, the lens can't do its job, and that's why people will have like when they look up close, oh, it's blurry. Now, as you age, that lens in your eye actually gets thicker and less flexible. So although the neurology works and the muscles work, when you hit about 40 or so that lenses doesn't do this anymore. It goes like this, er, like little by little, right? So it can't magnify anymore. You don't have that magnification power as you used to, and that's why you have to put readers on. So you know, those over the counter readers like plus one plus two and so forth, plus one, two. Those are magnification powers, so those leaders compensates for what your lens can't do anymore. But when you're younger than 40, like earlier in your life, if you have eye focusing problems up near, it's not necessarily the lens, it's the muscle or the neuropathy going to the muscle, and that's something you can rehab. And in reality, like the vestibular system and other systems can actually cause issues with that as well. That's eye focusing. The next thing is eye teaming, or binocularity. So that's how your eyes team together. So eye tracking, your eye movements, is like this, or like that. Binocular vision is going like this, in and out. So when you go out, that's divergence, when you go and that's convergence, that's what that's what binocular vision is. And there's all these different levels of it, but given the time, I probably can go over all of them, but, um, there's different tests to test binocular vision, right? So one bread and butter test everyone should be doing is the cover test, where you cover one eye, you see what the eye does. Cover the other eye, see what this eye does when it's looking at a target. Then you do an alternating cover test, where you see what the eyes are doing when you alternate. So if there's a lot of movement, they might have like a strabismus or an euphoria. And what that means is that the eyes are aligned together. So I guess we talked about screening. So going back to the whole screening part, why did things get missed? Right? Some people might just do a quick cover. That's like, boom, boom, boom, boom. Like two seconds, and that's done where you might have to actually hold it longer to see if there's anything going on. There's ways of actually missing it if you go too quickly, or if you just don't do the test. But a lot of times people brush to them because they're looking for really, really bad stuff, and not these, like, like, kind of like, these more mild cases that could be like, causing issues where people but they don't like, it's not like killing them, if that makes sense. So someone could have, like, a little convergence insufficiency and like me, and function totally fine, where, if my vision was really bad, like my convergence issue was really, really bad, I probably wouldn't be to compensate for it, and that's maybe why I got missed for so many years.

Dr. Ayla Wolf: 21:31

One of the questions that I often ask my patients when they say that they have blurry vision is, I ask them, do you notice your blurry vision like most frequently when you're changing your gaze from something, say, far away to something near or vice versa, as a way of trying to tease that piece out of you know, is your blurry vision there all the time, or is it just that when you are shifting your focus from a Near target to a far target, or vice versa, that that shift in focus actually takes you a couple extra seconds to bring that target in, and that helps me to kind of clue into that binocular vision piece of it.

Dr. Paul Brewer: 22:07

and that's that part could either be like a eye teaming issue, or it could be the eye focusing issue, right? So we talked about going back to. Focusing? Do they have the power to be able to focus up close? Do they have the facility to be able to focus far and near, back and forth? So there's all these different elements, and that's a good question to ask, because then it kind of teases out. Okay, what test should I do? Should I do a facility test to see how well they can focus far and near. I test how well their eyes can actually focus individually and so forth.

Dr. Ayla Wolf: 22:39

Yeah. And then you also, like we mentioned earlier, when, when you're assessing people, you're also bringing in a kind of cervical and a vestibular component. So maybe talk a little bit about how you, you know, put more of this functional twist on some of these classical exams.

Dr. Paul Brewer: 22:58

Oh, for sure. Yeah. So this is good, a good case. I just, uh, bring it up. I mean, I just like to just show the videos, but I didn't get permission for the patient to share it. So, like, it'd be kind of cool to see it. But like, so this patient comes in, right? And, like, full on, has, like, an, like, it's called an intermittent extratropia. So like, the eyes tend to go out, like this, like that. And it was a huge one. So I was doing the cover that was, like, a lot of times you just see a little bit her when I could do cover test, it was like, Don't, don't, don't. Like, really bad, right? And in her case, she had a, like, a really bad distributor to dizziness, to get vertigo and so forth, right? And in her case, like when I did some integration stuff, which, time wise, I'm not going to go over all those details, but like when we integrated the vision of a server system, basically what happened is, when I did the cover test, again, it was almost aligned as a little movement. So in my opinion, in that case, part of the eye alignment issue, not part of a big part of that one was actually a visual specific integration issue, where sometimes, if we did the integration and they still have this huge angle, we know maybe it's more a visual pathway issue. So that's kind of one example of, like, why it's important to the other tests. Like, I think every doctor should be doing posturography. They should do balance testing. They should be, maybe even have a vng or do some kind of eye tracking test. And then they should also test how, like, the cervical positions actually affect eye alignment, because if you're turned this way and suddenly your eyes aren't aligned anymore, or they can't track, or they can't focus, that could be a cervicogenic issue. It could be errors in the proprioception the neck that are causing errors in the system where the vision can't compensate. But the reason why I think it's important is because I look at like, vision, vestibular, proprioception as like three maps, but they're intertwined, like Google, Google Maps. Like, you know, if you're driving, you're following a Google map on a road trip. Can you imagine, like, if you're following the Google Maps, and suddenly the path is like the like, the actual directions for the path on the map. I think this is the map, and the directions suddenly go like this now, and now you're seeing two different maps, but the direction is not on the same map. That'd be a lot harder to follow that map. Some people can compensate and still deal with it, but a lot of people will break down and probably get a car accident, right? So the same thing with the vision and other sensory systems, if they're not communicating as a team, as a family, and why we call ohana? If they're not ohana, then basically there's going to be more errors in the system, and there's a point where if there's too many errors in the system, the brain or the cerebellum can't correct for those errors, which causes mismatches, which causes or adaptive or maladaptive behavior or adaptations, or it causes injury, or so forth, right? So that's kind of what I look at now. Is like, well, how does each of these systems affect each other? So before just targeting each system individually, how can you integrate the systems together into one so they're working as a team? And then from there, you see how you can actually train each one.

Dr. Ayla Wolf: 26:17

Yeah, I love that. I often talk about it like a math equation. You've got these different sensory systems, and they all need to be kind of feeding your brain the same information, but in different formats. But it needs like one plus one plus one needs to equal three, otherwise you've got this mismatch. And then that drives the dizziness, the headaches, the neck pain, all the things,

Dr. Paul Brewer: 26:38

but and another thing too, is if you have too many errors, it's like if the vestibular system is pulling the body one way the vision is pulling the body another way, you get this push and pull all day long, right? So it's better to have them work together than doing this all day long, which can make the brain really tired and make you fatigued. So, like, a good example is a cerebellum, right? So cerebellum does a lot of cool things. Like, it does it deals with like, like, movement error correction, motor coordination. It does with planning and thinking. It does with immune modulation. It deals with emotions. Yeah, so those are things that the cerebellum deals with. So think about like this control center in the back of the brain, this little small brain that's helping all these sensory systems integrate, in a sense, right? If you have too many errors that little small brains, like, I can't do this anymore. So what happens your brain sits down and you're like, I hate this. I get dizziness. You have walking issues. It affects so many parts of the body. But in fact, another patient I just had recently, like, we worked on all this stuff, and I remember, agree this finished therapy, and she's telling me, she's like, man, you know, I got really kind of, like, I had all these emotional fluctuations during therapy when I was doing all these exercises you're assigning me. And I'm like, and I told her why, and she's like, Oh, that makes total sense. But the cool thing she said is that, like, I feel more emotional, sound now than I did before. Awesome. Yeah, so, and I'm not, I'm not, I'm not a therapist, I'm not a, you know, a psychologist or anything like that. But I think when you integrate systems, people can adapt better and compensate better and be able to control their emotions and so forth. Yeah,

Dr. Ayla Wolf: 28:24

you're taking all the errors away and just letting the brain able, like it's able, to then do its job. One of the questions I wanted to ask you is about the cervical ocular reflex. Can you talk a little bit about that?

Dr. Paul Brewer: 28:38

It goes back to those three maps again, right? You know, cervical proprioception, or somatic you get somatosensory input right from the proprioception, vision and vestibular and and, my opinion, I think vestibular is foundational in stabilizing the proprioceptive pathway and the visual pathway. So when you look at these reflexes, it's really like kind of an integration, like even the VOR reflex, the vestibular ocular reflex. All those three systems are communicating together to help each other out, but to also stabilize each other. So in some cases, it could be an eye issues causing neck issues. Other cases could be neck issues causing eye issues. So there's times where I we firm because they may have a subluxated joint, and I have to send them to this person to work on that, but they might have these underlying vestibular issues. And a lot of cases, too, when you talk about neck adjustments or manual therapy on the in the cervical region, sometimes you might have to do some vestibular integration to stabilize the vision and the vestibular before they do that actual manipulation or manual therapy, or even Acupuncture, or whatever you want to do, right? Because sometimes, if you don't have that sound stability between the systems. It doesn't matter what you do. It's kind of like when you get a massage, and then, like, literally an hour later, like, why am I sore again? You know? I mean, like, you feel all good, and then suddenly everything gets all tight again. It's really comes down to is, we call it in Polynesia, no fefe. No fefe means no fear. So we want to get people to the point where they have no fear. And what does that mean? If they're fearful, they're going to be in this fight and fight kind of situation, or they're going to be in a survival mode. And if they're in a survival mode, they're going to always be locked up. They're gonna have that constant startle reflex, really, like this, you know, like kind of like that, where they have everything contracted and road forward to protect all their vital organs and so forth. So if you're in this constant fear mode, then you're going to have neck issues. The neck issues are going to cause visual issues. But a roundabout way of talking about this reflex we're looking at really foundationally. Can you are they in the survival mode or in the performance mode? And we want people to be in the performance mode, and there's going to be this ebb and flow between everything, but obviously we want people to be more on that performance side, so that they're not that's when they're going to have issues with the neck, issues with the eyes, issues with the vestibular so first thing, obviously, going back to the full foundation level, we have to look at the autonomic system, because if they have This autonomy and so forth. It's hard to have a stable communication between the vision, the vestibular and so forth. Now, at the same time, those systems will affect the automaticity of the body as well, because if you have underlying visual vestibular integration issue that can cause, you know, autonomic dysfunction, and cause immune issues and cause gut issues and cause like even like emotional issues, like we said before. So in reality, like we're when we're looking at these systems and tests, we have to see how, like, the neck and the movement of the neck and the body will affect your visual pathway to eye movements. So sometimes the person that maybe be turned this way might have way better eye movements versus looking straight ahead. So we know that there's something going on with that cervical region or the body that could be affecting the visual pathway, and they all run through the same thing. I mean, the same like cerebellum controls the air correction. Than all of them. The frontal lobes control the, you know, contralateral movements. So like in reality, you got the same parts of the brain that are affecting the kind of different pathways. So they all work as a team. And going back to the reflex, right? If you if you have poor reflex or poor communication, you're going to have errors in one of the systems. Yeah.

Dr. Ayla Wolf: 32:37

And then I think you brought up that important point, that when you have lots of errors in these different systems, it can actually tax the autonomic nervous system and drive some of these dysautonomia type symptoms as well. Talk a little bit about light sensitivity. You know, when we were talking earlier, I really liked what you said about light sensitivity, the term itself almost being as vague as when people say, I have pain, in the sense that it can mean a lot of different things to different people. So talk a little bit about when someone says, I have light sensitivity, what other questions you ask, or what it is that you're thinking in terms of, like a differential diagnosis.

Dr. Paul Brewer: 33:15

That's a good question. So, yeah, light sensitivity can mean so many things. It's photosensitivity is the name for photophobia. So there's all these different terms for I don't like light you know, for me, when I'm when I hear someone come in, I'm like, Oh my gosh, that means absolutely in my head. I'm like, thinking, okay, that means absolutely nothing. Let's just do the test right, because it could be so many different things. So dry eyes can cause license sensitivity, because if you have a poor tear film, so you got your eyeball, eyeball, tear foam on eyeball. If this tear film is unstable, it causes exposure to the front of the eye to air, and when there's exposure, there's a trigeminal nerve. It's like the sensory nerve, it gets stimulated, pretty crazy. And when it gets stimulated, you feel that burning sensation or achiness or whatever. And then the brain's like, oh, I don't like that. Throws the fire engine on, lacquer around, produces all this tears, and suddenly get all this wateriness, right? So a lot of people are like, Oh, my eyes aren't dry. They're watery, but watery eyes are typically pretty hallmark for either allergies or dryness. So like, that's one thing that can cause the licensivity, because when you have all this over stimulation, it's hard to focus. It could be a gaze stability issue, like we mentioned before, if you have poor gaze stability that can cause light sensitivity. It could be a poor people or effect. So the people is that black circle that's the people, and the muscles around the iris can either contract or die, like it big when it contracts, that's a parasympathetic response, or rest and digest, but not really rest and digest, but and then when it gets dilated. It can be it's a sympathetic response. So when you're outside, automatically, your eyes constrict, kind of like an aperture in a camera to let less light in, because if it's bright, it gets smaller, so there's less light coming in. But if you have poor automaticity in this, and it goes like more like this, slowly. Or sometimes they have what's kind of poor sustained people are with contraction. So they go like this, and then suddenly goes like that. It can't sustain. So you have this, like, evident flow of light coming in and out, so the brain can't process that, which can be light sensitivity as well. There's all these different things. Those are, like, one of many things that could be that can cause these issues with light sometimes even, like, oh, go ahead, yeah.

Dr. Ayla Wolf: 35:41

Sensitivity to flicker as well, which you have basically a test where you can measure if somebody's extra sensitive to the flickering of lights Correct.

Dr. Paul Brewer: 35:50

Yeah. So I guess going back to the light sensitivity too, like, it could be an eye teaming thing. So people have, like, a it's got an intermittent extratropia. So sometimes their eyes go out. Sometimes it doesn't that. Sometimes the symptoms for that is light sensitivity too. So they're closed when I when they're outside, and they're more sensitive light so there's all these things that can cause it. So basically, I guess what we're looking at is, like, it's not, like, okay, they have light sensitivity that creates a great symptom, right? What's actually causing it. So, like, that's the same thing with red eye. Like, oh, you have red eye. It could be allergy, it could be bacteria, it could be viral, it could be so many different things. It could be an autonomic dysfunction. It could be inflammatory. So there's all these different things that could be so when someone comes in with lights and severe red eye, I'm like, okay, great. Let's just do the test and see what's going on with the body, right? The same thing with the flicker rate. Like people that have concussions, they might have poor processing of like flicker rate. So like, when we say flicker rate, that's like hertz. So when you look at like a fluorescent light, now I might, I'm pulling numbers on the area now, so I can't remember the numbers. I always have to look them up. But like a fluorescent light might be like, I don't know, 60 Hertz or whatever, but if your brain can't process those hurts, or if it's kind of dysfunctional, fluorescent lights, might, the flicker rate of a fluorescent light or a TV might bother them. So that's a whole brain thing as well. So things like that can actually affect you. So if lights bother you, you. It could be a flicker frequency, like processing issue, it could be a dryness issue, and so forth.

Dr. Ayla Wolf: 37:22

Got it, and then you have this very cool tool where it flickers at different frequencies. And then you have your patient look at it and basically tell you when they see the flicker start, and then when they see it go away, and that tells you kind of if their range of perception of that flicker is kind of within a normal range, correct, correct,

Dr. Paul Brewer: 37:45

yeah, because concussions can actually affect that. And so, like the test, what it does is, like it flickers, where you actually see a flicker, right? So sometimes, when you have a fluorescent bulb, or whatever, you'll see that kind of flickering of the light. So it's flickering at a lower Hertz. The faster it goes, the harder it is to eventually see. So eventually, when it's a written number, where it's flickering so fast, and even when you see light that it's not flickering, it's still flickering. It's just flickering at such a high speed that your brain and eyes can't see anymore. And sometimes people have, like, a higher issue, or they see like, they have such a higher, like flicker rate, where they're seeing pretty much everything. So all these little nuances of the light can bother them. It's like over stimulating them. That goes back to whole error correction, like there's already so much your brain can handle and so much your breaking filter. I guess, going back to the whole concussion thing, this podcast is about like a lot of times concussions affects the brain's ability to correct error and filter information. So when it can't filter information, it can't correct errors anymore, or at a reduced rate. That's where you have all those symptoms, like licensivity, dizziness and so forth. That's what it comes down to, is like being able to, like, filter we can't. People that have brain issues, they can't filter out information. So now, like, instead of seeing like parts of things, now, like, everything's coming into their brain, their brains like, oh my gosh, what's going on? In fact, I, in my opinion, your vision itself like there's so much information just looking around you, like I'm looking at this, there's all this stuff around me, like I'm right in front of this huge window where I'm looking outside too. If my brain couldn't filter all this out, all this information will be coming in. I'll just go system overload. So the brain is really good at filtering out certain information coming in where it's good at picking out the most important things. That's called a perceptual like a perception span. So perception span is the ability for the brain to like taking critical information and apply it. People that can't do that either can't see anything, or they see too little, or they see too much, and then that creates this filtering issue, kind of a funnel effect, which can cause more errors and cause symptoms and so forth.

Dr. Ayla Wolf: 40:04

And I would imagine a lot of the visual motion sensitivity that people experience, part of it is their brain failing to kind of filter out the unnecessary information, and therefore their brain is just bombarded with every single thing that's moving in the environment.

Dr. Paul Brewer: 40:21

Yep, that's that's, like, that's part of the equation filtering and error correction, right? So, like, there's too much information coming in, brain can't filter it. There's too much errors, brain can't correct for it. Thus, the motion sensitivity,

Dr. Ayla Wolf: 40:35

And when you're incorporating a lot of the visual and vestibular and proprioceptive information by kind of cleaning up a lot of those errors, then, as a outcome of that, I imagine you're seeing that the visual motion sensitivity is also improving

Dr. Paul Brewer: 40:52

Correct Yep. So if we can give the brain specific activity. So, you know, through testing, we like, okay, these are the pathways that are efficient. These are the exercises that work for this patient, and by activating that part of the brain it we're not like fixing them, and we never fix anyone. But when we give their brain activity, their brain can interpret information in a different way. So we're helping the brain be able to interpret the incoming information in a different way, be able to filter in a different way, and be able to correct error in a different way. Is ultimately what it comes down foundationally. In fact, a good example of to explain this pathway, it's called the odor loop. So the odor loop was actually developed by a guy in the Air Force way back when, and implicitly, it's an input processing output, but ultimately his the odor loop is input, or like observation. So like all the incoming sensory information from vestibular to vision and so forth. Then you have and then you have orientation mechanism in the brain. So the orientation segment is based off, like from the info coming in. You're going to process and package it in a certain way, based off your genetics, based off previous experience, trauma. Based off, even religion, cultural views, because all that modes how you're going to bias yourself to the incoming information. And that's the orientation. Then it goes to a decision making process. And that decision making process is like, do you decide what to do? Like, am I going to if the ball is flying at my face, am I going to let it hit my face? Am I going to move out of the way? Am I going to catch it? That's the decision. And then the motor response, the action. So observation, orientation, decision action, Oda loop action is basically what you're going to do, like the actual motor movement itself. Then there's obviously these feedback loops that go back and forth, that go in a cycle. I I kind of coined this term called Vision decision action, and because I said, firstly, you made all the sensory as vision. So vision decision is that orientation decision together in action. So that's kind of what I explain to people when we're actually explaining this loop. So when you're in a car, you have all this input coming in. Can we change the orientation and decision making processes to be able to again, correct error, be able to filter out information and be able to make better decisions

Dr. Ayla Wolf: 43:23

and do it in an appropriate timeframe as well, I'm sure, because obviously, visual processing and reaction time are key components of all of that. I know that there's some interesting research and talking about when, when people have concussions, they may not necessarily have like, a full on peripheral visual loss in a certain visual field, but the way that their brain is processing peripheral vision can change. Can you talk a little bit about that?

Dr. Paul Brewer: 43:52

That's a That's a good question. So, like, there's a difference between actual loss nerve damage, right? Like something's broken and has a stroke and there's black stroke, yeah, and even those, it might be like a temporary loss. So the question is, is it a completely permanent loss? It doesn't matter what you do, it's going to always be dark at that spot, right? So a good example of like glaucoma. Glaucoma affects your peripheral vision. It affects your peripheral vision, and so when you have really severe glaucoma, this is all you see. Eventually, if you don't get it treated, or you don't slow down the process, that's like permanent loss. Like it pretty much doesn't matter what you do, you're not going to get the full extent anymore, where in concussions, you might have either a temporary loss or a constriction. So, like I kind of differentiate permanent and constriction. So when you have a constricted visual field or partially, it's not like you have a black spot here. You still have all this stuff here, but your brain can't process it as well as it used to. So when you have poor peripheral processing, it actually affects your central processing. So they work out in the hand. There's these two different loops that kind of work separately, but they stabilize each other. So when you have poor peripheral processing, that leads to gaze stability issues, it leads to eye tracking issues, it leads to visual sensitivity and so forth. So constriction is a different thing, where you don't have permanent loss, where you can actually rehab that pretty well and easily.

Dr. Ayla Wolf: 45:29

And are you rehabbing that by giving people different exercises?

Dr. Paul Brewer: 45:35

In that case, it kind of depends. I mean, sometimes, sometimes they might need a vestibular integration, like, like, do visual vestibular integration exercises I see a lot of times where you do that, where you're integrating the two systems together, and it opens up to periphery, because now they have better processing. Sometimes you might have to do like, stuff like, where you're doing a peripheral central integration with like, it's called like vectograms or stereopsis, or like depth perception type S, or exercises. So like, you have these polarized glasses on, you see this 3d image. And by working on the eye teaming together with peripheral processing that helps open up the periphery. So really, it's not like you're doing something to make it open up. You're just giving the brain an activity to be interpret the incoming information differently. So one example someone can do is like they can actually look straight ahead, and instead of like, looking up at the lines of the corners of the room, so like, say that picture behind me right pretend like that's the actual wall the back of the room. Instead of me looking up at each part of it. I'm using my I'm looking straight at I'm using my peripheral and I'm using my peripheral vision to follow the edge of that painting. I'm not moving my eyes at all. I'm just using my peripheral vision. Okay? I see the, I see the top corner. It's like, kind of bluish. I see the, you know, the top right corner over here, it's red. And so forth. By using your peripheral vision, so there's activities you can do to kind of open up the periphery. That's just one of many. Yeah,

Dr. Ayla Wolf: 47:12

yeah, yeah. And. That sparked another comment, I think, that you had made in one of the courses that I had the honor of taking with you, where you were saying, like, when people have that kind of peripheral visual dysfunction, if they're doing, like, potentially the wrong exercise, or where they're doing a lot of exercises focusing on convergence, where you're training them to actually just focus on one target that's really up close. You can actually be kind of like training the problem, so to speak, if part of their actual problem is that they're not their brain is ignoring all of this peripheral information. And so I think that really teases out the fact that this type of vision therapy is incredibly complex, because everybody's issues are very different, and people need very different type, you know, types of exercises. There's not like, hey, let's just run everybody through all these different exercises. Yeah,

Dr. Paul Brewer: 48:10

that's actually a good point you brought up. So, like, vision therapy, right? Like, you go online, you're like, oh, I have an it should go online. The first thing you're probably going to see is pencil push ups and bead string or Brock string, right? So a lot of these docs would like, like that, just random sign, oh, just do pencil push ups, just do Brock string, and you'd be fine, right? And reality, if you have a divergence issue, so they diverging your eyes out. But you have good convergence you could it can have the same symptom as a convergence insufficiency, where you have issues focusing up close and so forth. So someone's like, oh, yeah, just do all this convergence stuff over and over again. So you're making that convergence issue even stronger, but you're making that divergence worse, which can make the problem even worse. So that's the thing. A lot of people just say, Oh, just douche pencil push ups, broad screens, like it could be so many different things. So in some cases it might actually help the situation, but in a lot of cases, it may not. That's the biggest thing is that people go online they like and there's a lot of good information online. Don't get me wrong, because I use online for a lot of stuff too, but it's about finding out where the deficiencies are first, because certain activities can make it worse by going too focal or too central too quickly, where you have to be opening up the periphery to stabilize the central area. Another example is even like, like, I get us a lot too. There's a lot of great functional guys out there, physical therapists and chiropractors and and so forth, you know, everyone. So I'll get a patient where, literally, you know, they've they do vestibular therapy. They call, I went to a vestibular therapist, and their extended visitor therapy is either walking on a balance beam or getting spin in a chair or doing a bunch of like, cracking stuff like this, right? And in reality, those are great things, but that's not what they needed. They needed a specific path to be activating their vestibular visual system, to get them the brain processing things differently, versus randomly just throwing them all over the place. I see that time and time again with that kind of stuff as well.

Dr. Ayla Wolf: 50:13

Yeah. I mean, it really all comes down to having the right type of exam and the right person to be able to diagnose what that particular individual is struggling with, to then be able to find the right types of exercises.

Dr. Paul Brewer: 50:28

Yeah, for sure. I mean, that's, that's the thing too. Like, and I'm still learning a ton, right? I'm like, I don't think I'll ever be a master of stuff, but, like, I'm constantly learning, so all the times I'll call I'll call it my functional neurologist, friends, you know, colleagues and like, Okay, I have this case. This is what I'm doing. What am I doing? Wrong, right? And they'll give me such good information that's super awesome. Like, I have people in every single field, like MDs, chiropractors, physical therapists were like, I might have a case that I need help on, and I'm usually calling out a state, because there people in other states I call I'm like, and I'll share my case, and sometimes they'll call me up and share their case too, as well. So we have this good collaborative team where, where we're all really good at we're doing, but at the same time, we're all learning still. And I think that's the key. Is that we have to always learn. If you get to the point where you think you know everything, then that's where you're going to start failing. I think that's why I can go the same lecture over and over again, and I learned something new. In fact, a lot of these ones again with the characters doing so if that, you know, like you listen to these videos over and over again, every time I listen to it again, I'm learning something new. Because the first five times I didn't catch something that I caught the fifth time. You know exactly,

Dr. Ayla Wolf: 51:38

exactly. And there's so much about the brain that we're still figuring out. So it's impossible for anybody to say that they've got it all, that they've got it all figured

Dr. Paul Brewer: 51:47

Well for sure. Yeah, it's hard. I mean, it's out. like every person's a new puzzle. It's like putting a puzzle together every single time, but it's a different picture.

Dr. Ayla Wolf: 51:57

Yeah, I mean, I learn new things from my patients every single day, because every single person walks in with their own kind of unique, unique set of issues that you've got to then figure out. So in terms of kind of wrapping up, is there advice that you could give somebody who's. Out in the world who's maybe had an initial eye exam told their vision was normal, they're still struggling with visual symptoms. What would you say to that that individual,

Dr. Paul Brewer: 52:24

that's a good question, like, probably, like, go find either a functional optometrist, like a neuro optometrist, or a functional neurologist, or something that maybe you can do more testing, and it's not like anything that the doctor is doing wrong. I mean, like, it's kind of like, this is a good example. I go to my primary care right, like, and it's like, they couldn't do so much, and sometimes you just got to find a specialist that can diagnose your issue. Like, I had a good example. Like, I surfed my whole life, literally, and in my ears, I have what's called external auditory exit ptosis, which is like this, bone growth inside the canal. It's not it's on the outside of the eardrum. But when you're in the ocean, a lot the it basically closes off the bone growth and closes off the canal. So it's super small. My right ear was, like, literally, 97% occluded, right? So I go to my primary care and then like, Oh yeah, you have an ear infection. Give me your drops. Like, you know, it feels like it's getting better, but not really. I'm like, what's going on? Like, I like, I went to Hawaii. I was visiting Hawaii, and I used to dive all the time. I dove, like, literally, three feet in the ocean. I'm like, Oh my gosh, this hurt. This is weird. And I went back to my primary care. When I got back, they're like, Oh yeah, everything's fine. You're good. I'm like, and I have, like, I have a otoscope, you know, but you can't otoscope your own ear. And I follow online to have these video lines. And this is bad, like, saying this, like, as a fresher, got found, but, like, I get this video otoscope, I just look in, I'm like, Oh my gosh, my freaking ears, like, like, 95% occluded, you know, this is crazy. And then so I sent an appointment with the ENT, which is a specialist now, right? And I go into the anti office, and I'm like, you know, the MA is getting my history. And I'm like, oh, yeah, I think I have a 95% external auditory exitosis. And I can see that Ma's face, like, you just Google that, like, in her head, you know, you see, like her face, like she's like, You're so stupid. I'm like, okay, whatever. I just see her face, like, that disgust, and I kind of, like, tone it down a little bit. I'm just like, whatever. And then the doctor comes in. He's like, Oh my gosh, you're totally right. Like, yeah, it's totally clueless how to get surgery on it, because that's only way to get rid of it. But that's a good that's a good example, right? Like, it's not, I don't blame, I don't blame my primary care, I don't blame and I don't blame anyone. It is what it is, you know, like, there's only so much people can do as doctors, I think as patients, we have to be more forgiving, because we expect the doctor to know every little thing. And in reality, if you're not specialized in something, you're not going to know it. So my advice is, be more forgiving to your doctor, and maybe ask them, like, hey, is there someone you can refer me to? So a lot of times, those doctors will know the specialists in town. Or you can, like, go online and look at the different sites, like, you know, the Carrick side, or Nora or whatever. Like, there's a optometric rehab site that you can look up doctors in your state. But at the same time, just because you're trained in any situation in any institution, doesn't mean that they're a good doctor either, right? So you can have all the fellowships and all the things in the world, but does it make you a good doctor still? So that's one caveat, that when you do look up these people, it may not be the situation for you, or maybe it might might be the right fit for you from the doctor. So that's, I guess, my biggest advice I give people, for the patient side and for the doctor side, you know, I just say, continue learning. Like, literally, like, don't stop learning. Because if you stop learning, then you don't there's always going to be changes in research and changes in how we treat people. And if you're doing things 20 years back, it may not be as effective today.

Dr. Ayla Wolf: 55:53

Yeah, yeah, wise words. Well, let me ask you one question. Where can people find you?

Dr. Paul Brewer: 56:00

Diverge performance is the my instagram handle the website's diverged performance.com as well.

Dr. Ayla Wolf: 56:08

Okay, perfect. Well, I could put that in the show notes, and then your practice is in Boise, Idaho.

Dr. Paul Brewer: 56:14

Boise, yep, uh huh.

Dr. Ayla Wolf: 56:15

Okay. Super Excellent. Yeah. Thank you so much. Thank you for coming on the show and for giving us a lot of insights into what is incredibly complex. And I hope to have you back on where I can pick your brain some more on other specific topics that we didn't get to today. So thank you so much.

Dr. Paul Brewer: 56:35

Yeah, thank you.

Dr. Ayla Wolf: 56:39

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