Hello, and thank you for the opportunity to speak. So today I'm going to be talking about neuroplasticity and strategies to enhance injury prevention and rehabilitation. So neuroplasticity is the capacity of your nervous system to adapt under different contexts. So the two different videos I have here are different contexts. So on the right is actually how different areas of your brain will change connectivity during development. And then on the left is actually how your brain changes following joint injury or specifically an ACL injury. And I'll get into that later in the talk. But my hope for at least this talk is to give you all at least a glimpse of how adaptive your nervous system is and how sensitive it is even to any small changes or an orthopedic injury and how clinicians can take advantage of this phenomenon to optimize care and rehabilitation. So neuroplasticity is a large all-encompassed term. It's more of an umbrella term that involves a bunch of different processes. So for example, you'll see increases in cortical areas associated with skills. So if you were to take a survey and if we were to measure all the orthopedic surgeons in here and we were to actually look at their hand area and their motor cortex, it would likely be a lot larger than the non-surgeon or this is also true in musicians compared to non-musicians. Additionally, associated with skills, you'll get new neuron support cells. It's still a debate if any sort of neurons can actually be formed after in the adult. However, you'll get at least support cells and glial cells that will form in those areas. And this leads to this neural efficiency hypothesis where it's the ability for your brain to function and perform at a lower level for the expert. So on the right, you'll actually see there's a study that used different brain imaging techniques that compared different sort of groups of individuals. So on the top right, you'll see the group of non-athletes as well as fencing and karate at the bottom. And what they asked individuals to do is do a single leg stance. And what you'll see for the non-athlete, they activated their brain much more compared to the other groups followed by the fencing group and then the karate group. So for the non-athlete, they activated a lot of their cognitive areas as well as their visual areas. And then I also mentioned in the previous slide that neuroplasticity also includes changes in connectivity. So how do we actually measure the brain? Well, my lab takes advantage of this tool called fMRI or functional magnetic resonance imaging. And fMRI has expanded a lot of how we understand the brain. Similar to biomechanics, it actually became more popular in the 1970s. And it allows us to take advantage of this phenomenon where blood oxygenation will actually shunt itself toward areas that are generating action potentials. And we can actually measure how an individual activates their brain during a given task. In our case, commonly we ask our participants to do some sort of motor task. And I also wanted to mention that commonly when we talk about the brain in the context of movement, we limit our conversations to usually the sensory motor cortex. However, your brain evolved in order, brain evolution was actually done so in order to permit movement where you'll actually take information across your entire brain, such as your visual cortex, your frontal cortex, even during very simple motor tasks. So if you were to ask as a clinician an individual to do something simple like a quad set, they are actually activating a lot of their brain. And they're taking in information from their environment, the affect of the clinician, as well as what they're attending to during that quad task. So my research group primarily deals with ACL injury. And a lot of the conversations surrounding deficits in ACL injury are typically tailored to the final motor output or some of the consequences we see following injury related to that final motor output, which include things like quadricep weakness or quad inactivation. We also use motion capture to measure how an individual moves during walking or how they might have some sort of asymmetries in their hop performance. But a lot of these final motor outputs are actually governed by neurophysiological processes. And we see these also change in those after an ACL injury, such as reductions in somatosensory feedback and proprioception. And more recently, we've actually discovered changes in brain activation, as well as neural excitability of the pathway that actually innervates the quads. So there's been several reports that have actually measured the brain in individuals following an ACL injury. And many of these reports have suggested that central nervous system adaptations may actually govern some of the persistent neuromuscular deficits we see following an ACL injury. So for the top right, the video is the top left report. What they ask individuals to do is they recruited individuals following an ACL reconstruction, and they also recruited healthy controls. And they asked them to do just a simple knee flexion extension task in the fMRI scanner. In the red represents individuals following an ACL injury. And the blue represents healthy match controls. So without me having to actually show you the stats, just qualitatively, you'll notice that there's a lot more red than there is blue, where individuals following an ACL injury will actually activate their brain much higher compared to healthy control, specifically in areas related to the frontal cortex for cognition, as well as the visual areas of their brain as well. So a lot of this led to some theories that individuals following an ACL injury actually up-weight resources in their brain. They actually end up almost performing similar to the non-athlete. And they up-weight their resources towards vision and cognition in order to perform simple knee tasks. So the use or up-weight of visual resources and cognition may be beneficial for individuals following an ACL injury in order to maintain knee stability. However, when we think about the context of using vision, if you think about today, how often were you walking around actually attending to your knee or looking at your knee? And this is actually an interesting study where they asked individuals to do a, just asked individuals to walk down a sort of rough terrain, and they actually tracked, they used eye tracking to measure where they were attending to. And what they found was that very little do an individual actually look at their knee during, or even their legs during any sort of walking task. Instead, individuals will usually look at roughly two or three steps ahead. And when we look at how individuals will return to sport, not just during simple knee tasks, but during a sport environment which includes several distractors such as the field or the ball or another opponent, we notice that these individuals will actually be put at risk because they're specifically those after an ACL injury because now they're asked to be in a visually demanding environment, which puts them at risk for further injury. So the next question is, what do you do as a clinician? Well, there's a bunch of different studies that have looked at different sort of rehabilitation techniques or techniques to augment therapy. And all of them are pretty beneficial, but they all kind of govern a similar idea, and that is to reduce the reliance on vision and cognition. So for example, one of the things that we've used in our lab is stroboscopic glasses, essentially reduces the amount of information that a person's actually visualizing by doing this sort of stroboscopic technique. And we asked individuals to do some sort of training following an ACL injury, and we found that the use of stroboscopic glasses, which reduced visual reliance, actually targeted some of those brain areas we saw following an ACL injury, and it also equated to better balance scores as well. Another technology we've also taken advantage of is virtual reality, and that's actually putting the athlete in the sport environment, but in the rehabilitation setting. And the beneficial virtual reality is that it actually adds distractors, and you can actually build these motor patterns in the context of a sport environment. And then again, it also reduces attention to an injured joint. And there's several different types of technologies you can use. They can be expensive and inexpensive, like Google Cardboard, anything really. But essentially we use it in the context of having individuals actually visualize where they're actually, their sport-specific environment, or adding some sort of distractor while they do simple tasks, like a quad set. And then finally, there's been some, a few reports about whether there's actually a neural predisposition to ACL injury. And when you look at ACL injury, it's commonly in the context, or when you look at videos, it's commonly in the context of where an athlete will be looking at some sort of visual distractor. And that leads to this sensory motor mismatch, where an individual will then lose balance and coordination, and then subsequently rupture their ACL. There was a study where they actually, it was part of a longitudinal concussion study, where they actually measured individuals' brains, and then some of these athletes actually ended up rupturing their ACL. When they went and looked back at the individuals that ruptured the ACL, they actually saw a disconnect between their sensory cortex and their cerebellum, which is involved in sensory motor matching. And there's also been some reports that are currently in review from our lab, that individuals who are at risk for an ACL injury, have high dynamic knee valgus, actually activate their brain differently compared to those who do not. And then finally, another sort of technology that we've been exploring, currently we just finished a longitudinal study with 130 athletes, but it's how can we actually, in individuals who haven't actually experienced an ACL injury, can we improve neuromuscular prevention training by using augmented reality, which provides implicit feedback. So this sort of square, the athlete's asked to do a squat, and they don't know how the square or the rectangle is actually moving, but it's all based on their biomechanics. So we're actually implicitly providing feedback. Thank you.

neuroplasticity

injury prevention

rehabilitation

brain imaging techniques

ACL injury