Dr. James Beck 00:00:00
Hello and welcome to our second Expert Briefing of the year. This is our fourteenth year, second of 2023. I'm your host, Dr. Jim Beck, the Chief Scientific Officer at the Parkinson's Foundation. Today I want to welcome you to our topic, A Balancing Act: Freezing and Fall Prevention in Parkinson's. While aging may put us all at an increased risk for falling, people with Parkinson's disease have twice the risk of their peers. Today we'll learn how freezing and other movement and non-movement symptoms can contribute to falls and how to lessen the risk of that. Before we begin the formal briefing, I'd like to share a little bit of information about the Parkinson's Foundation.
The Parkinson's Foundation is a nonprofit focused on bettering the lives of those living with Parkinson's through improving care and advancing research. Importantly, everything we do is done in close concert with our community to ensure that our actions are aligned with the needs and priorities of those living with Parkinson's disease. We have several goals at the Foundation to fulfill our mission, and we're focused on improving care for those living with Parkinson's, advancing research toward a cure, and empowering our global community through education events just like this one we're hosting right now.
Before I begin, I want to take a moment and acknowledge the connection we all have across the globe. Yesterday was Parkinson's Awareness Day, it's Parkinson's Awareness Month, and today the Parkinson's community for our Expert Briefing joins together to learn and to connect. Thank you all for being here for yourselves and for our community. Feel free to share in the chat, as many of you have been doing, where you're joining from. Some of the places are just amazing. I've had to Google them. They're really beautiful parts of the country and beautiful parts of the world. Thank you all for joining. Now I'd like to transition to a poll.
We want to understand your connection to Parkinson's disease. Take a moment to fill it out, whether you're a person with Parkinson's, a spouse, partner, physician, clinician, scientist or researcher. Take a moment and let us know where you're coming from. If you're joining us from Facebook Live, please use the comment section and let us know there, and we can help compile that together.
We'll be closing those in just a moment and getting a chance for everyone to see as we quickly get a sense of where they are. Not surprisingly, a lot of the people here who've responded are those living with Parkinson's disease, as well as their loved ones and caregivers. I'd like to welcome some of our professionals who've joined, the physicians, the nurses and others who are really involved in Parkinson's. Welcome to our Expert Briefing today.
I'd also like to acknowledge the Light of Day Foundation, who has generously provided support to our Expert Briefings today. They are really closely aligned with our mission of the Foundation, and again, their funding has made today's programming possible.
For your convenience, we're recording today's Expert Briefing, and the recording will be available at Parkinson.org/ExpertBriefings. We'll also be emailing a link to the recording and other resources related to today's topic to all who've registered for today's briefing. No need to go to that link directly; we'll send an email to you. But keep in mind, if this is your first time joining us at Expert Briefings, you can look at previous recordings as well.
Now I would like to take a moment and introduce our expert speaker today, Dr. Colum MacKinnon. Dr. MacKinnon started studying the neurophysiology of Parkinson's disease in 1994 during his PhD training at the University of Toronto. He subsequently received training at University College London before joining the faculty at Northwestern University for about 10 years. He then transferred and is now currently a professor of neurology and the director of Movement Disorders Laboratory at the University of Minnesota. For the past 20-plus years, Dr. MacKinnon's research has been focused on understanding the mechanisms contributing to impaired control of upper and lower limb movements in people with Parkinson's disease.
In particular, he's interested in mechanisms causing disorders in posture, balance, gait and particularly the phenomenon of freezing of gait, which we know really impacts people with Parkinson's disease. He's currently conducting several NIH-funded studies examining the emergence and progression of gait and postural instability in people with Parkinson's, and the effects of deep brain stimulation on drug-resistant motor features of Parkinson's, like freezing. These are symptoms that Parkinson's medication can't ameliorate, but we're wondering whether DBS can.
Dr. MacKinnon is an avid cyclist, a Nordic skier and an aspiring Highland bagpipe player. Dr. MacKinnon, welcome and thank you for sharing your time and knowledge with us today.
Dr. Colum MacKinnon 00:04:59
Good morning, everybody. Let me get my slide sharing going here.
Okay, hopefully that's showing up okay for everybody. Thank you, Dr. Beck, for the kind introduction. It's great to be here.
Good morning, good afternoon, good evening, no matter where you are. A special shout-out, actually, to people joining us from Canada. I'm Canadian, so I will be giving this talk in Canadian English, but I can translate to American English as needed. I'm going to provide some information on freezing and falling and potential strategies for reducing the potential for falls in people with Parkinson's disease.
But my real goal here is to provide those that are on this call, whether you're a caregiver, whether you're a provider or whether you're a person with Parkinson's disease, with one or two nuggets of information or strategy that will help you move and prevent falls. That is my goal today. I have no disclosures.
I'm going to talk about the factors contributing to falls. I'm going to talk briefly about the principles of balance that you need to follow, and I'm going to identify six primary barriers to safe and effective standing and walking. Then we're going to talk about the strategies and interventions to improve posture, balance and walking, and hopefully these can prevent falls. I'm going to discuss the ingredients of quality movements.
Let's start off with falls in Parkinson's disease. Falls are a significant cause of disability, reduced independence and reduced quality of life. This is really, really clear. Unfortunately, approximately 60% of people with Parkinson's disease, nearly two-thirds of people with Parkinson's disease, will have a fall over the next year. That fall could be serious or it could be very benign. Two-thirds of these people will fall several times throughout the year, recurrently. The severity and frequency of falls increase as the disease progresses to the point where there's a loss of mobility, wheelchair burden, and obviously at that point in time, the fall incidence will go down.
The consequences of falls are pretty clear. There's risk of injury. The incidence of hip fracture is four times higher in people with Parkinson's disease. It greatly restricts activities of daily living. Most importantly, and I'll get to this in a minute, it creates a fear of falling, and that really impacts quality of life. It also adds to high levels of stress in the caregivers.
The primary contributors to falls in people with Parkinson's disease are twofold. One is postural instability, basically the ability to maintain balance while you're standing or walking. On top of that is the phenomenon of freezing of gait. Freezing of gait together with postural instability explains about 80% of the falls that we see in people with Parkinson's disease. Falls typically occur during turns. By far, that is the most risky behavior in which falls occur. Bending forward, standing up or other activities like initiating walking or trying to avoid an obstacle can also contribute.
I'll get to this in a little bit more detail, but falls usually happen unrelated to dominant environmental hazards. The dominant falls that happen actually are not trying to avoid an obstacle or not tripping, but rather self-induced movements of the center of mass. These are movements in which you are self-initiating, and it's not due to a bump, it's not due to a trip. It's you initiating the motion yourself. That's a really important feature.
Dr. Colum MacKinnon 00:08:43
The problem here overall is we have this vicious circle of Parkinson's disease, in which you have these motor features like gait alterations, postural instability and falls. Because of those motor features, you tend to move less. You tend to be more sedentary and have less physical activity. The lack of physical activity and a sedentary lifestyle are also associated with depression, apathy and cognitive decline, along with other non-motor features.
Along with that, there is fear of falling. If you're afraid you're going to fall, that's going to increase anxiety, depression, disability and activity avoidance. What you get is this vicious cycle of motor features, sedentary lifestyle, fear of falling, depression and apathy. What we want to do is break this cycle. Our goal here is to provide strategies to prevent a sedentary lifestyle and increase physical activity. As a result, that will reduce the number of falls and injuries, but also complications and comorbidities like cardiovascular disease and osteoporosis.
How are we going to break the cycle? Here's my recipe for breaking the cycle. This is a recipe for a great movement hot dish. I live in Minnesota, and hot dish is a really popular meal here, better known as a casserole in Canada. Here's the recipe: a big dose, four cups of strength, lots of strengthening, and I'll get to that in quite a bit more detail. Also, lots of range of motion. We're going to add in four cups of strength, four cups of range of motion, and then on top of that, into the mix, we're going to add some postural challenge. We're going to do that to taste.
We're going to start with a little bit of postural challenge, see how that goes, and we'll start increasing postural challenge as things go and as we continue to be safe. Similarly, we'll start to add some cognitive load, and we'll do that to taste as well. We'll increase cognitive loading as we go. These are the main ingredients of the hot dish. These are what give you great quality movements, posture, stability and good walking. We also have to add tater tots, because if you have a hot dish in Minnesota, you need to have tater tots. That's a bit of an aside.
Here are the basic principles of balance. To maintain balance, you have to have a center of mass, which normally sits right behind your belly button, typically if you're standing, and it projects downward between your feet and sits right between your two feet if you're standing, a little bit in front of your ankles, right in the middle.
If you lean forward, your center of mass moves forward, and the key feature is your center of mass stays within your base of support. This grid area I have here, that's where you want to be. You want to have a nice base of support and make sure your center of mass is within that base of support. Now, I mentioned earlier what happens in people that have freezing and postural instability is when they self-initiate a movement, that center of mass gets outside of the base of support. Something has to happen to prevent you from falling.
You can do a couple of strategies to keep yourself stable. You can increase your stance width and then move your center of mass over. You can externally rotate your feet outwards. That increases the mediolateral, the side-to-side base of support, but also decreases the front-to-back base of support. Or you can actually stagger your feet. Now you've got an increase in the width and an increase in the length. If you're standing there talking to someone, or you're on your cell phone, these are really simple strategies just to make sure you are stable in case something bumps you or in case you lose your balance.
Dr. Colum MacKinnon 00:12:28
If you want to do a movement, you're standing there and you want to move your center of mass forward. Now my center of mass is in front of the base of support. That requires you to take a step and reestablish a new base of support. Now you're safe. You can do that in a reactive mode if you're bumped and your center of mass goes outside your base of support; you do a quick step. Or if you're going to self-initiate a step, you're going to move your center of mass yourself outside of the base of support, and you want to do a step that's appropriate.
But what happens if the center of mass moves forward and your step is not sufficient? This is what often happens in people with freezing: the step is insufficient. It's not effective. Your center of mass continues to be outside the base of support, and you're still in a state of falling despite the fact that you took a step. Your step needs to be larger. It needs to be much more effective. That's the primary cause of falls in people with Parkinson's disease who fall, that step is not sufficiently effective. What it requires is, now you've got a center of mass that's continuing to move forward, you're continuing to fall, and you're going to require a second step or maybe more to reestablish a new base of support. That has to be done really, really quickly.
Here's the major challenge of standing while walking. I'm just going to introduce you to my friend Sven here. Sven actually has mass, he has a motor that generates locomotion, and he's got a nice base of support. This Sven here is from Sweden. We're going to turn on his locomotion, and he can walk, and he is nice and stable. He can do this all day long. To walk, you basically need two things: you need a motor, you need something that's generating a pattern, and you need a really good base of support to provide stability.
But let's say Sven goes to the Swedish Institute for Neuroscience, and he learns a lot. When he learns a lot, what happens is his brain gets bigger, his mass of his head gets larger, and he likes to wear a nice Swedish hat here. Now his mass up high is really, really large. This is the same motor, the same base of support. This is what happens when you move the mass up too high, and now you're really unstable.
This is the classic characteristic of human walking. We have something called the two-thirds/two-thirds problem, which means that two-thirds of your body mass is located two-thirds of your body height above the ground. This is inherently very, very unstable, and something we take for granted every time we take a step. If you're a 150-pound person, 100 pounds of your body is sitting two-thirds of your height off this very small base of support. It's what we call an inverted pendulum. It's very, very unstable.
When you're standing, your center of mass is within your base of support, but as soon as you start moving, like you start to walk, now your center of mass is outside your base of support. When you're walking, your center of mass is outside the base of support. The real challenge to your system to maintain balance, to maintain walking, is to control this big mass that's up high. We far too often focus on the legs and focus on the feet, but the biggest control problem and challenge in people with Parkinson's disease is controlling the upper body.
When you're walking, what you want to do is provide vertical support against gravity, and you want to maintain balance, but that's really critically dependent upon control of your trunk. You also want to make sure you have a good foot trajectory, so you have a nice safe step and good toe clearance. The other things we want to do are generate energy, absorb energy and have a nice stable head that we can view things from.
I'm going to talk about freezing of gait. I'm not going to go into too much detail of the wording here, but freezing of gait is an episode in which there is an inability to step effectively despite the attempt to do so. What happens is you're trying to take a step, and either that step doesn't occur or it is not effective. When that step fails, it's often combined with trembling of the knees, short shuffling steps, maybe a complete lack of movement, and that can last anywhere from one to two seconds, eight seconds to 30 seconds, depending on the severity of that freezing episode.
Dr. Colum MacKinnon 00:16:59
About half of people with Parkinson's disease will have a freezing episode. As disease increases, as severity increases, the likelihood of freezing also increases. When do freezing episodes typically occur? Again, similar to when falls occur, freezing typically occurs during turns. Now you can imagine turning, freezing, and that precipitates a fall. That is, unfortunately, extraordinarily common.
Freezing also occurs very commonly when you're passing through narrow or congested pathways, such as approaching a doorway; approaching a destination, so you're approaching a chair and you need to slow down; or when you're starting to walk from the standing-to-walking situation. What's really common to all of these tasks, all of these movements, is they reflect transitions in movement state: going from one movement state, walking, to turning; from standing to walking; from walking at steady state to slowing down. Transitions are the key feature of what precipitates a freeze.
These freezes can be worsened by a variety of things. We now know that the incidence and severity of freezing can go up dramatically in situations of anxiety and stress. If you add cognitive loading, if you're trying to dual task, trying to be on your phone or talking to a friend at the same time, the incidence and severity of freezing can also increase. Environmental conditions can also increase the severity and frequency of freezing, for example, if you're trying to walk in a darkened room. Freezing is more pronounced with advanced disease and when off medication in general.
The features of freezing include what we're calling hastening, which is an increase in the number of steps you're taking and a decrease in the step length. I'll come to that in just a minute and why that's important. At the onset of the freeze, the foot or the toes do not leave the ground or barely clear the supporting surface. The key feature here is when you're having a freeze, there are two problems, and we'll come back to this several times. The two problems are the location of your feet, so where the location of your center of mass is, and the movement of your upper body.
If your feet are not in the correct place, if you haven't executed an appropriate step, if it has not gone in the right direction, and then you have a trunk that's accelerating away from the base of support, the likelihood of a fall is much, much higher. Two problems: controlling the trunk movement and controlling where your feet are in space. After the freeze has occurred, there's often a period of alternating trembling of the legs at a frequency somewhere around three to eight times per second. It is during this period any further attempt to step is unlikely to be successful.
For those on the call who experience freezing of gait, and this is something we try to emphasize quite a bit, once this trembling freezing occurs, it's very unlikely that you're going to have a successful step. You need to stop trying to step. Stop trying to step. Reset, get yourself back to a standing, balanced posture that's stable, and then reinitiate a step. I'll give you some strategies for reinitiating the step. I think that's really, really important. Once the freezing episode has happened, you need to stop and you need to reset. Very important. If you try to take a step, the likelihood of a fall is much, much higher.
Freezing is commonly either precipitated or relieved by various cues. I'll talk about cueing in a minute. Freezing can be very asymmetric. It can be very different on one side than another. Some people will freeze in one direction and not in the other.
Dr. Colum MacKinnon 00:20:45
Here's a fairly famous video of a gentleman with very pronounced freezing. What I want you to do with this video is basically look at the features about balance that I was talking about. He's trying to take a step. This caregiver gives a cue and says, “Step over my foot.” The cueing helps him step.
Notice the forward posture, short shuffling steps, but he's keeping the center of mass over his base of support, so he's still stable. He goes to take a step, and then that cue works. Now he's lost control of vertical support, short shuffling steps, center of mass gets in front of the base of support, and down he goes. His ability to turn is extremely compromised.
Here's another video of a gentleman with freezing of gait, and this is actually data that was captured in my lab. I'll do it in real time first. He's going to try to take a step with his left foot and has a freezing event during that step. We actually thought he was going to fall during this particular trial. This is a good example of the trunk getting forward of the feet. The first step is not accomplished and is followed by these short shuffling steps, which are also too short. The center of mass is in front of the base of support, and the likelihood of a fall is fairly high. Actually, this gentleman was falling far too often.
This is the same video but in slow motion. Hopefully this is showing up for you. There he tries to take a left step, fails, tries again. Now the center of mass is going forward, but the feet still have not released. Short shuffling steps, but he's able to catch up and prevent a fall.
Those are the things to think about that are going to be really important and are going to cause a fall. How are we going to prevent these falls? I'm going to give you a whole list of barriers to safe and effective standing and walking. These are things I want you to focus on that allow you to have better quality movement and potentially prevent a fall. The first is force generation, which is basically strength.
Dr. Colum MacKinnon 00:23:02
What we know is as a person ages, as you get older, particularly past the age of 60, your ability to produce force, your strength goes down as a function of time. The good news is we know that as a person ages, you don't lose your ability to become stronger. If you go into a progressive strengthening program, you will increase your strength.
On top of the getting-weaker-with-aging problem is the problem that, in people with Parkinson's disease relative to their matched cohorts, they are weaker. Off medication, both the flexors and extensors of the muscles tend to be much, much weaker than their matched controls. If you take medication, your strength gets better, but you're still weaker than a matched person, a matched cohort. Really importantly, though, this loss of strength is much greater in the extensors than it is in the flexors.
That's a really important point for clinicians or caregivers to keep in mind. The extensor weakness tends to be more than flexor weakness. What do extensors do? Extensors are the muscles you need to support yourself against gravity. Your ankle extensors, your plantar flexors, your knee extensors, your quads, your hip extensors, your glutes, and your back extensors are critical for supporting yourself against gravity. Those have to be strong enough to support yourself against gravity to give you proper posture. They need to be priority number one when you're going through a strengthening exercise.
This is just a quick little summary of the muscles you need for vertical support, trunk support, generating power during walking, and muscles of toe clearance. I'm not going to go through these in great detail, but most importantly, these muscles of vertical support include the ankle plantar flexors, the knee extensors, the hip extensors, and the back extensors. Those are the ones that can provide vertical support.
Then what are the muscles that support this big two-thirds mass that's sitting up high? That's your hip flexors, your hip extensors, and your core muscles, your rectus abdominis, your trunk flexors, and your back extensors. Those sets of muscles have to be strong before you start to attempt large movements because the ability to support yourself against gravity and the ability to control your trunk are key before you start to walk.
Okay. In general, and there's quite a bit of literature on this now, progressive resistance exercise is where you want to go. This means that you want to exercise with strength training two to three times per week for 20 to 60 minutes or more. There's very good evidence that if you just do progressive resistance exercise two times a week for 90 minutes, so that's an hour and a half twice a week, you can get significant improvements in both flexor and extensor strength.
Dr. Colum MacKinnon 00:26:16
If you're in a muscle strengthening program, the key feature is it needs to be progressive. You need to be increasing the weight over time. As long as it's safe and you're not hurting yourself, continue to increase the weight as needed. Target all the major muscle groups from top to bottom, but I really recommend focusing on the extensors: ankle, knee, hip, and back; the hip flexors and extensors that control your trunk; and these side-to-side hip muscles, which we call the abductors and adductors, which control the trunk.
Progressive resistance exercise is probably most beneficial when combined with instability training and flexibility exercises. Range of motion is ingredient number two that people need to focus on.
We have data, and lots of experiments have shown, that the range of motion in people with freezing is decreased both actively and passively. This is actually just from a study we conducted looking at the first-step distance in a person with freezing versus a person who doesn't have freezing. What you'll see is this first gray step here is too short, and the second step is too short. This is a non-falling gait initiation. This is a normal gait initiation for a person with freezing. This dashed line way up above here is what the normal distance should be.
In people with Parkinson's disease, the first step is too short, and in people with freezing, it's far too short. The other feature on the right-hand side is that the distance of the toe from the ground is also too short. Your toe clearance when you're doing that first step is far too low, so you're much more likely to catch your toe and trip and fall.
We also know that if you're doing very short steps over a long period of time, particularly if you have freezing, that step will get shorter and shorter and shorter. Again, short steps mean you have a smaller base of support, and your trunk is continuing to accelerate forward. There will be some point in time when your trunk gets ahead of your feet and your step is not sufficient, and the likelihood of a fall is much, much higher. We call this the sequence effect.
Okay, so how are we going to get past this? One strategy is to use something called LSVT BIG.
[Video Clip] 00:28:38 The video describes the principles of LSVT BIG, including high intensity, large-amplitude movements, speed, range of motion, and helping the brain recalibrate movement patterns.
Dr. Colum MacKinnon 00:29:01
Intensity is really important. Do movements with vigor, with commitment. Make your movements big — really big, where your body thinks it's starting to move. Take the time to know where your legs and feet and trunk are moving in the exercise. Those are the basic principles of this BIG and LOUD program, which is common throughout the world. We know it's very effective, and we know that the effects of this training last over time. Not only do you get improvements in balance and posture and position sense, but after the program, those benefits last over time.
Again, the principles are large-amplitude movements, make the movements as big as you can, do the movements with vigor, with high velocity, so intensity, and try to have a sense for where your limbs are. Practice knowing where your limbs are. Those are the basic principles. Those are very effective in improving your balance, your stability, and preventing falls.
Movement rate is another feature that's extraordinarily important, and this is something that most people aren't aware of. This is just a quick video of a gentleman doing movements of their forearm back and forth. They're going to move at a very slow rate. You'll hear, beep, beep, beep, beep. He's asked to hit this target and can do this task just fine.
When the movement gets faster, beep, beep, beep, beep, notice how the movement falls apart and you have these moments of upper-limb freezing. It goes back to the short rate, the low rate. He can do the task, and it goes fast, and the movement falls apart.
Dr. Colum MacKinnon 00:31:07
The pace or the tempo at which you do movements is really, really critical. If your cadence, which is the number of steps per minute, is really high, you're taking a lot of steps really, really quickly, and your stride length is really, really short, you're much more likely to have a freeze, and that freeze is much more likely to be associated with a fall. Again, you need to have this principle of doing low-rate movements, low-tempo movements, which most people are easily able to attain, and do them as large as possible.
Big steps, big strides at a lower cadence will be much safer than steps that are short and steps that are done in a fast sequence, which are much more likely to have a fall. That's movement rate. I'm going to go past this really quickly. The movement rate depends on the person, but most people will fall apart somewhere around two movements per second. Try to move at movements that are less than two movements per second. One movement per second, 1.2 movements per second, is typically ideal.
This rate barrier unfortunately is resistant to levodopa replacement therapy and DBS. Strategies, again: slow down, reduce the movement rate, keep the movements large, and execute the movements with vigor.
Self-initiation is also a critical problem. I'm going to go past this here. For example, if you want to start walking from a standing posture, you want to accelerate your center mass forwards, and you want to push yourself over to your stance leg, the leg that is going to provide your support. Now, the worst thing you want to do if you're going to start walking, if you want to do a right step, is actually to lift your right foot up. If you're going to do a right step, the first thing you do is you put weight onto your right foot. If this is my stepping foot, the first thing I do is I actually shift my weight over to the right.
That allows you to push yourself off and go to the left, onto the stance side. This is what we call an anticipatory postural adjustment. It's something your brain knows about. It's something that comes from the brainstem, and it's essential for getting a really good quality first step.
Dr. Colum MacKinnon 00:33:22
In control subjects, people who don't have Parkinson's disease, we've studied this a lot. What this graph shows is the muscle activity here, the shift in pressure beneath the feet, and the shifting of your weight from side to side before you take a step. This is what we call an APA, anticipatory postural adjustment, and that's a really good example of a really good quality step.
This is what it looks like in a person with Parkinson's disease who does a self-initiated step. They start stepping on their own. The muscle activity is really poorly organized. There's no shift in pressure, and there's no shift in weight from side to side before they start walking.
Again, this is what it looks like in a person with Parkinson's disease with a self-initiated step, so an uncued step. But if we ask the same person, on the same day, off medication, okay, rather than self-initiating, when I flash this light in front of your eyes, I want you to step. When you see that, start walking. This is what happens when we provide a cue.
With a cue, the muscle activity is way, way better. You get the shift in pressure. You get the shift in weight. If it's self-initiated, about one in five trials, you are at risk of a fall. With a cue, that goes down to about one in one hundred trials. A simple visual cue, a simple acoustic cue, allows you to move way, way better, and the likelihood of having an inappropriate gait initiation and the likelihood of a fall drops dramatically.
We've looked at visual cues, acoustic cues, vibrotactile cues. They all work equally well, and we've looked at different timings of how you provide a cue. For everybody out there right now, whether you're a caregiver or a physician, here's the simple answer of how you provide cueing to a person with Parkinson's disease when you want them to initiate a movement. What you do is you say, "Get ready." Go. "Get ready?" Go.
Dr. Colum MacKinnon 00:35:24
You provide a warning cue, a pause, and then a go cue. If you do that, the cue will be very, very effective. Now, the pause turns out to be really important because the pause after the warning allows the brain to plan, put the action together, and the Parkinsonian brain, your ability to plan a movement, to build all the bits and pieces together, is intact. You can put beautiful quality movements together if you're given time. What a cue does is it releases it.
I say, "Get ready," warning pause, you plan and prepare. When I say, "Go," that go, that sensory signal, has access to that beautiful plan and releases it, and it will be almost normal in terms of magnitude and duration. When you provide a cue, again, the number of times with a step that's a risk of a fall is about one in one hundred. Without that cue, it's about one in five.
Okay, so a question I always get asked, and we finally did the right experiment, is: can you self-trigger yourself? Can you just say to yourself, or can you push your own button and say, when that button says beep, start walking? We actually did this experiment. If the button was given to me and that button provided a sound for you to step, we get a nice improvement in your step quality, depending on whether it's an acoustic cue, a mechanical cue, or vibrotactile cue. We get this beautiful improvement in your stepping quality. On this y-axis is the magnitude of the step, which is really, really nice.
Now what we did is we gave that button to the participant, the person with Parkinson's disease. We said, okay, now you press the button. The person presses the button, they get the cue. What happens to the quality of that step initiation? It doesn't get better. It does not get any better. When you are trying to self-initiate, when you're trying to self-cue yourself, the quality of the gait initiation is not improved.
You cannot self-trigger yourself. To get the benefits of cueing, it has to be externally delivered. You have to have the feeling of the cue coming from somewhere else, and that's really, really key.
Dr. Colum MacKinnon 00:37:41
The postdoc who was working in our lab at the time, Matthew Petrucci, said, well, what would happen if they self-warn themselves and then they got a cue afterwards? We also did that experiment. We would look at that, just if he pressed the button, gave the external warning, what happened to the quality of movement? Well, it was beautifully improved. We knew that would happen. But now what we did is we had the person with Parkinson's disease press the button, but it's not giving the go cue. It's giving the warning cue.
It'll give a boop, and then three seconds later, it would get a beep. The warning cue, the boop, is provided by the participant. The go is provided externally. When we do that, the movement is rescued beautifully. We get a really nice quality movement. Actually, even if the person presses the button and they don't get the boop, but they get the beep afterwards, it also improves. Bottom line is you can't self-trigger the go cue to get going, but you can self-trigger a warning cue, and when that's delivered with a go cue afterwards, it's highly effective.
Okay. Other barriers: balance and posture. This is pretty obvious since this is one of the issues we're talking about today. What are the elements of an effective balance program? First of all, it needs to be safe. Use postural support as needed. If you're not feeling safe with a cane or you need a four-point walker, that's fine, but still continue to do a posture or balance training program. Make sure it involves weight-bearing, and that can be progressive as necessary. There are body-weight support systems out there, or you can go to an aquatic program where you have body-weight support. It needs to be progressive, and that's a feature of all this training. It needs to be progressive.
You have to get challenged, and you have to progress over time. In terms of this, the movement needs to put the body in an extended position that challenges the postural control system. It's not okay just to stand there and bounce. You need to put yourself in a challenging position that challenges your posture, and you have to do something about it. In the more advanced stages, you can go to challenging terrains or obstacles or uneven surfaces as you progress. It's also important to have some sort of high cognitive or position sense or motor control demands. Again, you want to be challenging cognitively. You want to be challenging motorically.
Dr. Colum MacKinnon 00:40:09
Those are really important features of a postural training program, and we recommend about three times per week for about 30 to 40 minutes. Great examples are aqua aerobics, tai chi, dance, Rock Steady Boxing, yoga. These are all very, very good at challenging your posture and improving postural stability. Remember, the number one cause of falls in people with Parkinson's disease is a problem with postural instability, and that will be exacerbated by freezing.
Now, I'm not going to go into this in detail, but for those who are interested, there is a fall prevention program out of Australia called the Weight Bearing Exercise for Better Balance, or PD-WEBB. On this slide, you can actually see the website. If you go to that website, it'll give you the full program. It's a PDF of the whole program. The beauty of this program is it's very progressive. It allows you to progress where your center mass is. It allows you to progress the amount of weight-bearing that you're doing. It progresses the base of support from larger to smaller, and it also progresses whether you're using arm support or not.
It involves endurance as well, so increasing endurance. It's got a strength component, and it has exercise all the way from standing to reaching to walking to sit to stand. All these ingredients are in there. It's a highly well-developed, validated, and very effective fall prevention training program, so I highly recommend looking at that.
Last barrier that I want to talk about is cognitive reserve or dual tasking. One of the parts of the brain that's really critical for controlling walking is the cortex. The cortex is involved in planning, initiating, decision making, and dual tasking when you're doing movements. Then there are all these other areas of the brain, the spinal cord, brainstem, basal ganglia, cerebellum, which are doing their thing, but the cortex has a really pivotal role to play. Let me explain it here with this little diagram.
Dr. Colum MacKinnon 00:42:16
If you're cognitively intact and motorically intact, typically gait is automatic. You walk, you can talk, and you can converse with your friends, and it's performed without thought. You have a consistent step length and timing, and you can do whatever you want. The gait is just happening. What happens over time in people with Parkinson's disease, partly due to the loss of dopamine, is you get an increase in the variability of the step length and the timing of your steps. When you start to get this variability, it's like you don't exactly know where your feet are going to be and where your center mass is going to be at any point in time.
In order to deal with this perturbation to your walking, you increase your cognitive contribution. You start thinking about your walking more, and that's a good thing. That may not even be conscious, but you're really starting to focus on your walking. Priority number one when you're walking is thinking about your posture and your balance and your gait. Priority number two is thinking about other things and phones and other responsibilities going on. Priority number one needs to be your balance, your posture, and your walking, but that requires cognitive load.
One of the unfortunate things of Parkinson's disease, in a large proportion of people, is that cognitive capacity decreases. There tends to be cognitive impairment in far too many people with Parkinson's disease. Now you have problems with your gait variability, with the consistency of your stepping, with where your trunk is going. Now you want to say, I need to focus on this, I need to think about my walking, but the cognitive impairment compromises that ability.
Now you've got two issues: you've got the motor problem and a cognitive problem that are interacting. As a result, you end up with more variability of where your steps are, more variability in where your center mass is, and the inability to appropriately cognitively focus on it. What often happens, what we think, is people start prioritizing the thinking over the maintenance of balance. That gets you into a situation where falls are highly likely.
We know that if we have people do tasks while they're dual tasking, so they're on a phone or we give them some subtraction by sevens, the impairments get worse, particularly in people with freezing. If you're dual tasking and you have freezing, your stride length will get shorter. Again, short stride length, short steps tend to be problematic, and as they get shorter, your likelihood of a fall goes up. The duration of the postural shift when you're stepping becomes more problematic. Your ability to turn becomes more problematic when you are thinking and dual tasking. The variability of how you're standing increases when you're dual tasking. This issue is also associated with more freezing episodes.
Dr. Colum MacKinnon 00:45:12
If you are dual tasking when you're walking straight, when you're turning 180 degrees, or in particular when you're turning 360 degrees, you're much more likely to have a freeze, and that freeze is much more likely to be severe. If you're having problems with freezing, stop trying to do two things at once because we know that exacerbates the freezing episodes.
A group out of Belgium has really worked on a nice framework for how to select exercise and training in people with Parkinson's disease, in particular specific training for people with freezing. Those exercises can be generic exercises, freezing-related, or freezing-specific exercises. Generic exercises we recommend for everybody, no matter whether you have freezing, occasional freezing, or frequent freezing. They're really, really important to maintain.
If you're having occasional freezes, there are freezing-related exercises, I'll come to that, which are very important. If you're having very frequent freezes, there are also very specific exercises that can be given. Generic exercises include what we talked about before: dancing, yoga, physical therapy, aquatic training, tai chi. These are very effective programs for improving postural stability and potentially reducing falls.
These generic programs, strengthening and moving with balance challenges, are very good at improving balance and preventing falls, but these generic exercises do not contribute to the alleviation of freezing of gait. These are not freezing-specific exercises. They're postural stability exercises, but they're not freezing-specific.
There are freezing-relevant training exercises. These are exercises aimed at reducing the severity and amount of freezing following the intervention, but they're not aimed at overcoming immediate freezing episodes. These include cognitive training, doing motor tasks with dual tasks — so you train actually doing a dual task — combined with balance training. Treadmill training or curved treadmill training is very, very good, and obstacle avoidance training. These are all freezing-relevant exercises. They're actually very, very effective.
If the freezing is very frequent, then you can go to a very specific set of exercises using cueing, action observation, and a fall prevention training program.
I'm just going to touch on a fairly recent study, which is a randomized controlled trial that was conducted in people with freezing. What they did is they did either traditional motor rehabilitation or an adapted resistance training program with instability. They did this three days per week for 12 weeks. Each session lasted 80 to 90 minutes. What this adapted resistance training with instability does is it puts it all together. It requires you to do a highly complex motor task that requires high cognitive load, proprioception, so sense of limb, and high motor control demand. It's a very challenging task.
Dr. Colum MacKinnon 00:48:25
You do this for upper and lower limbs, and you do this frequently. They compared that to just traditional stretching and strengthening exercises. This is just a figure showing the kind of exercises they did, but the key feature here is, in addition to doing progressive resistance training, they're doing that training on a progressively unstable surface, from a foam pad to a DynaDisc all the way up to a Bosu ball. Progressive in terms of strength, progressive in terms of instability.
What they found is that the adapted resistance training with instability improved the freezing-of-gait ratio. This is actually an indicator of when freezes are occurring. General motor signs, measures of quality of life, and gait initiation got better, and they actually did imaging in the brain, and the locomotor regions of the brain and the brainstem were actually activated better. They also got improvements in what we call the New Freezing of Gait Questionnaire, which is our measure of the severity of freezing, and in general motor scores, severity of the motor features.
This was really encouraging to see that we are getting to a program that incorporates everything — balance, strength, range of motion, challenge — that seems to be effective for people with freezing of gait. Again, breaking the cycle. What do you need to do in order to improve the quality of movements? You need strength. Strength in particular in your extensors and muscles that control the trunk.
Range of motion is absolutely key. That's where you're getting four cups of range of motion, lots of that. You need to have activities that challenge your posture, and you need activities that challenge your mind as well. Dual tasking. And of course you need tater tots.
The work I'm presenting here is the work of a lot of individuals who work really hard to get this data together and to put the story together that helps you. Many thanks to everybody in my lab and our center who have contributed to this. I'll stop here.
Dr. James Beck 00:50:38
Thanks very much, Dr. McKinnon. That was a fantastic talk, chock full of information. I think it's really clear there's a lot to be learned here and an issue which many people who experience freezing of gait are really desperate to find ways with which to do it. I really appreciate you taking the time to talk with us about that.
Some questions have come in, and I'll give you a chance to take a sip of some water. I think you nicely presented some different strategies with which to address freezing of gait, and clearly exercise and strengthening is a clear step to that. One of the things I want our listeners to know is that the Foundation has recently come out with some exercise recommendations, not only for a person with Parkinson's, but also for trainers on how to interact with a person with Parkinson's if they're not familiar with it. We'll include that in our follow-up around that.
It seems like that is the key ingredient: the strength and the muscles in order to really help eliminate that. Maybe that's why you put it number one on the list of strategies.
Dr. Colum MacKinnon 00:51:45
Well, I'll just narrow it down. There should probably be two number ones. The two number ones, which I don't think are separable, are strength and range of motion. It's fine to have lots of strength, but if you have no range of motion, then the movement quality's not going to be great. You need both.
Dr. James Beck 00:52:03
When you talk about range of motion, if you might touch on that a bit more, is it just simply stretching, like static stretches, to make certain your muscles are limber? What is it? How is that fully accomplished?
Dr. Colum MacKinnon 00:52:22
The simplest solution is increasing your flexibility. There are two things going on. One is we're aging, and with aging your flexibility in general gets worse. With decreased flexibility, the range of motion, in particular if your lower limbs are what we're talking about here, becomes restricted. On top of that, you've got rigidity. What rigidity does is it stiffens up the joint, so when you try to move a joint, it gets resistance, and that will also reduce your range of motion. You want to be able to move your limbs through as large a range of motion as possible.
I actually had a gentleman asking me about how he should walk, and I said, I want you to walk with as big a range of motion as you can. Make that stride as long as you can, and I want that arm swing to go above your shoulders. Or use Nordic walking poles, and that will also force you to actually have an increased range of motion.
What you'll find is if you just say, I'm moving big, you realize when you take a video, you see the range of motion is not sufficient. If you exaggerate it, and you exaggerate it purposefully over a long period of time, what you end up with is a range of motion that's pretty good. It may not be great, but pretty good even when you're not thinking about it. That's what our goal is: to have a big range of motion, big strides, the ability to move your lower limb over a large range of motion. If you get into trouble, you need to take a big step. That's going to be avoided, or you're less likely to take a short step that's going to end up in a fall.
Dr. James Beck 00:54:00
That brings up a question. One of our viewers, Fran, had asked: how important is it to have arm swing? Is that really critical in order to maintain balance, or what are your thoughts?
Dr. Colum MacKinnon 00:54:12
The arm swing is really important. The arm swing is linked to what we call a locomotion pattern generator in your brain. When you're normally walking, that pattern generator in your brainstem and your spinal cord is saying, when you step forward with your right leg, your left arm needs to come forward. When your left leg goes forward, your right arm needs to come forward. Those are linked together in phase. What happens with Parkinson's disease is you get asymmetry, and you start to lose that arm swing.
The thought is, if you force your arm swing, you're saying to that locomotor pattern, if my arm swing is big on my left side, my right step is going to be bigger. The two are going to be locked together, and they're going to learn. If you really force a big arm swing, you're also going to force a big step length. Really trying to keep that arm swing is really, really important.
Dr. James Beck 00:55:12
I think that ties in nicely to your comment about LSVT BIG and those movements. I've known people who've done LSVT LOUD and tried to increase speech, but that seems to not persist. Do you find that the movement component of it for walking and balance persists longer? You mentioned that it did seem to persist fairly well.
Dr. Colum MacKinnon 00:55:36
I can't say that we have data that supports that it persists longer than the LOUD program. We need more long-term studies with LSVT to know what intensity and duration of the program is necessary for maintaining past two to three months. I think the data I presented really quickly on the slide was a four-week follow-up, and it was persistent over four weeks very clearly. But we need more data or more trials looking at the persistence over a much longer period of time. It'd be really nice if you had a four- to six-week program of LSVT, if it would persist for three to six months, that would be great. Just go back and do it again.
Dr. James Beck 00:56:19
Yeah, fantastic. Gamify it, for instance. You can do it all the time at home.
Dr. Colum MacKinnon 00:56:24
Right.
Dr. James Beck 00:56:25
When we're talking about these types of changes around exercise or therapies, any advice on how you find a person to help you do that? From your experience, is this something you can — someone's listening to our discussion today and says, I'd like to try to do this. I know I need to strengthen my core, my legs. Can they just go to the gym, or are there other guidelines? You mentioned that website. I haven't had a chance to take a look at it. Does it provide that kind of specificity for someone to be able to try to do this themselves, maybe with help of a trainer or physical therapist?
Dr. Colum MacKinnon 00:57:05
That Australian program on postural training, balance training, is actually a program that's designed initially for having someone watch you, but actually being able to do it independently at home. There's nothing fancy about the equipment that's being provided, so it's actually designed to be much more usable outside of a clinic, outside of any kind of supervision, as long as it's initially trained to be safe.
I think there are a number of similar programs like that, progressive resistance training exercises that are now being designed to be done either on the web, or once you learn it on the web, then you can do it independently. In terms of resources, I don't have a decent answer for that. Parkinson's Foundation is one way to go. I know Stanford University actually has a website for looking at resources for exercise in general.
I can speak for the United States: there are a lot of different programs that have really established themselves as effective and meaningful programs for exercise, and that includes Rock Steady Boxing programs, dance programs, tai chi programs. Most big centers have something like that. If you just do a quick search for exercise and Parkinson's disease in your community, you'll probably come across something like that.
For people who are in more rural communities, it can be much more challenging because typically they won't have that kind of program, and they need to rely on either the local gym or even better would be some sort of web-based YouTube program that they could have access to.
Dr. James Beck 00:58:53
Absolutely. The Foundation itself has Fitness Fridays, where we're able to offer these opportunities for people who are not around. I know we're coming to the top of the hour, and I hopefully have just a couple more minutes of your time just to ask a couple additional questions. I know they've been coming through. For those who haven't been able to get their question answered, apologies in advance. We certainly do our best, and my colleagues will be following up, and we have our Helpline as well with which to take advantage of that.
A real practical question: you're a loved one with someone who has Parkinson's, and they fall. Is there any advice you have on how to help them up? What's the approach about that? I know we've been talking about trying to prevent falling, but unfortunately, it does happen, and I don't know if you have experience or suggestions on how to approach that.
Dr. Colum MacKinnon 00:59:49
The advice I have, and actually this is fairly recent with me preparing for this talk, is that Postural Stability Program out of Australia. The PD-WEBB program has a specific set of exercises and procedures for recovering from a fall, from getting up from a fall. Again, I can give that information to you, Dr. Beck, but it actually has a specific outline for dealing with that particular situation, and that's the only one I've actually ever seen.
Dr. James Beck 01:00:24
That's fantastic. We'll certainly include that in our follow-up email to our audience here so they won't have to necessarily dig through your slides. We'll call that out.
One last thing: for people who, I think, with Parkinson's really want to take control of their disease, and I think exercise is one way with which to do that, but sometimes it's not sufficient. Are there really no options out there to control these issues of freezing? It sounds like, of the strategies that you've discussed, deep brain stimulation might help alleviate some of those issues to help minimize freezing of gait, but it's not a panacea for it, I presume.
Dr. Colum MacKinnon 01:01:05
Unfortunately, the answer is, as you know, the response to levodopa for freezing — freezing can respond to levodopa dopamine replacement therapy very well initially, and then over time tends to become resistant. Similarly with deep brain stimulation, you can have a fabulous outcome in reducing your freezing or eliminating your freezing for quite some time, and then in far too many people, it'll start to come back. We know that those two treatments, those dopamine treatments, those basal ganglia-type targeted treatments, are hitting part of the circuit that's involved in freezing and certainly helping.
But the issue with freezing is degeneration in other parts of the brain that are non-dopaminergic. As those progress, the number of viable treatments drops dramatically. We think degeneration of the brainstem is a big player in basically the lack of response to any kind of effective therapies. Again, the only effective treatment we know of that might make neurons survive longer or be resistant to degeneration is exercise.
Dr. James Beck 01:02:17
Yeah.
Dr. Colum MacKinnon 01:02:18
There's good animal model data showing moderate- to high-level intensity exercise might be neuroprotective, and that's all we have right now.
Dr. James Beck 01:02:27
It certainly underscores the urgency of our Foundation and the community in trying to come to a solution and put an end to Parkinson's disease. Dr. McKinnon, I want to thank you again for your time, offering your knowledge, your wisdom today for our Expert Briefing on freezing and fall prevention in Parkinson's disease. I want to thank everyone who joined us today for our Expert Briefing.
We had a significant response, and as I mentioned, we can't get to all the questions, but please feel free to call our Helpline, 1-800-4PD-INFO. You can reach out to my colleagues, who will be able to answer your questions in real time.
Today marks the second episode of our 14th season of Expert Briefings. I want you to take note of the calendar and join us next on May 10, when we have an exciting topic presented by Dr. Roger Barker from the UK: Understanding Gene and Cell-Based Therapies in Parkinson's Disease. You can register at our website, Parkinson.org/ExpertBriefings, and we'll put a post of that in the chat.
Another thing that's more pertinent to our talk today about freezing and falling that happens to people with Parkinson's: this is a study that the Foundation is involved in, which could perhaps help if one does fall. The goal of the study is to test whether a generic drug that's available and helps people prevent osteoporosis may reduce the risk of fractures for a person who falls. I encourage those who are on here to consider signing up for this study as part of that process. It's online, and someone comes to your home in order to participate.
We have lots of resources available to help a person: our Aware in Care kits, our library, as well as our ongoing series, PD Health @ Home, from which you can watch many of our exercises, as well as Mindful Mondays. Don't forget other resources, including podcasts. If you're a professional, we have professional education CEUs and CMEs available, as well as PD GENEration.
PD GENEration is our ongoing study to offer free genetic testing and counseling to a person with Parkinson's in preparation for what we see as a coming wave of precision medicine therapies. Find out if you have a genetic form of Parkinson's disease and use that information to consider enrolling in upcoming clinical trials.
Last to point out is that we're here for you. Our website, our Helpline, via telephone or email — you can reach out to us anytime. Before you go, one thing I just want to point out to you is that as we end this webinar, your screen goes away, and there will be a survey that will pop up.
That survey will give you an opportunity to give us feedback, allow us to hear your concerns, your praise. We pass it on to our speakers. We use that to constantly improve our series, and we really incredibly value it. Please take the time to fill that out. With that, I bid everyone adieu, and we'll see you again come May. Thanks very much. Bye-bye.
