Clinical Reasoning Behind New Bertec CDP Training Scenes


Interview with Fernando Santos

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Interviewer: I'd like to introduce you to Fernando Santos - he is a senior product engineer at Bertec, working with mobility and multisensory interaction allied to wearable and XR developments. He has his Ph.D. in Biomechanics and Movement Sciences from the University of Delaware, where he studied the effect of repetitive head impacts in multisensory fusion. He has developed over 100 different virtual environments for research and/or commercial use, and is currently developing the next generation of visually immersive scenes for training using Computerized Dynamic Posturography, otherwise known as CDP. Fernando, could you tell us a bit more about your background, and your research?

Fernando: Sure. First of all, thank you for having me in this podcast, and a little bit of my history is… I have been developing and teaching about digital applications for physical therapy and healthcare since around 2008/2009, always with the emphasis in VR for balance assessment and/or training. During my PhD I studied dynamic, multisensory re-weighting in college athletes. So, our focus there was to study repetitive head impacts and concussion in the college community. To accomplish that, virtual reality was responsible for a big portion of our experiments, and sometimes we needed a visual perturbation. Other occasions, we couldn’t have a visual perturbation, and because of that, we had to always be changing the settings to achieve the goals. What I mean by changing the settings, is changing how the virtual scene, or the virtual reality application, was presented. So, that’s most of all because people with Parkinson’s, or people post-concussion, they react differently to every different visual presentation. So, they will have different visual sensitivity, and their balance and their whole movement will be different depending on what we present to them.

I also end up helping other researchers develop their VR scenes protocols and research ideation, is something that I still do nowadays, to always be helping the research community to keep with good research about multisensory or balance and the use of virtual reality for it.

Interviewer: Let's touch on some of the visually immersive scenes you're working on currently for Bertec, and the clinicial reasoning behind the decisions you've made, and are making. Could you tell us a little bit about how your work in developing these scenes has its basis in the science of balance? What clinical concepts are being incorporated into the technology?

Fernando: Well, before we go to the clinical portion of it, we have to understand that, a person, to keep balance, to keep from falling throughout their day, other than their own muscles, strength, and their physical body, they rely mainly on three sensory systems. One of them is vision. So, vision will give you the direction of where you are going, or if the world around you is moving. The next one is the vestibular system, most commonly known as your inner ear. It tells you if your head is rotating or translating, or if it’s moving in a certain way. The third one is the somatosensory, some people call it proprioception. It’s how your brain knows where your body is in space. For example, it’s how you know right now that your foot is probably touching the ground, and you don’t need to look to your foot. So, you’re doing this throughout your entire day, you’re using all those three systems to walk in an environment, and you’re always re-weighting the importance of them. A good example that we always give to that is, let’s say you’re walking in a room right now, and you’re using all the systems: your foot is touching the ground, your vestibular system is saying your head is in place, and your vision is saying you’re not hitting anything in your way. But if someone turns the lights off, you won’t just fall because you’re missing vision, what will happen is you will change the emphasis of those sensory systems. And now, to keep balance, you will rely more on your vestibular system and your proprioception.

So, with that in mind, any time we are creating any rehabilitation using the CDP we are thinking about all those three systems. For sure, the virtual reality is reliant more on your vision, so we have to think a little bit separated when we are talking about the virtual reality, but when we’re creating for the CDP, all those three systems are really important.

Vision is a great part of your balance in your daily life. For example, vision can be classified in so many different levels. If I talk to you about peripheral vision and central vision, for example, your peripheral vision is what you see on your sides. That is what is responsible for you to recognize your space. So, your notion of, is your world spinning, or, are you moving fast, so optic flow and everything, is done by your peripheral vision. The other part is the central vision. The central vision gives you that direction, so you know where you’re going, or the obstacles, and everything that is happening in front of you, helping you to plan your next movement. Everything then is related to your central vision. So when we’re creating new scenes, assessments and trainings for CDP, that’s one of the parts that we’re looking for. That’s why we have different settings, so you can have peripheral vision that will be more dense, so it will have more objects around, or less objects around. Because for people with motion sensitivity, for example, having a really busy background on the periphery, would be really hard for them. So that’s why, some people when they go to a grocery store, it can be kind of hard for them to walk in the aisle. It’s not because it’s very narrow or anything. It’s just because it’s so busy on your peripheral vision, that becomes really hard for people with motion sensitivity and with visual sensitivity to walk. There are some people that have problems with central  vision too, so we also have settings for that. We put obstacles, and we change colors, and we change the presentation of the objects too. Once I said color, it’s good to understand too that colors also make a difference when we’re creating new training and new assessments. We know like, a rose tone might be better for migraines, or a blue tone might be better for post-concussion. So, every time we’re building those scenes, all of those parameters are there. All of those parameters for us are there are we’re trying to recreate scenes that can encompass several types of treatments for different types of patients.

One addition that we now start to have more and more in our scenes is cognition. So, we’re also adding some cognitive aspects to it, doing a Stroop test, or math equations. So, it’s almost like a dual task where you have to stand still, see all the optic flow, and also do a math equation. So, dual task is another thing that is really important and interesting to us in the future and not just in the future but nowadays is really important. Almost everything you do in your life, every day you’re doing dual tasks all the time. You’re walking in your kitchen, you’re looking at your surroundings, but you also have to go and look how to open your closet, or how to open something, or carrying things in your hand, or texting in your phone and walking, all of this is part of a dual task, and you do that every day. So, we’re trying to incorporate all of this in our new scenes.

Interviewer: Thank you. In conclusion, can you talk a little bit about how what we know now about sensory re-weighting influences your approach when designing this technology?

Fernando: Posturography has been around since around the 70’s. Nowadays we have, I just did this search this morning, nowadays we have more than 1800 papers, studies out there about posturography. The difference with Bertec’s CDP, is that it’s a digital way to do it, a quantitative way to do it, and it’s also a safe way to do it. A lot of times, you know, I have patients, and we used to tell patients, let’s go for a walk around the clinic or something. But some patients are really insecure, and that was not that safe for them. So, we can do this training using the CDP, and then they would be prepared and be ready to do something more like walk around and actually having a more active type of treatment. That’s why I think CDP is really interesting for that.

Also, CDP encompasses the three main sensory systems: the vision, the vestibular, and the somatosensory. So, we have assessments to all of them, and we’re creating more and more trainings every day.

Another aspect of this whole multisensory paradigm and how CDP works is that we know that the older population has a worse multisensory integration than the younger population. We also know that people with concussion might have that problem, such as the older population. So, training those systems is really important. Most of the time when we’re doing rehab, we worry about one aspect and one aspect only, and the idea of being able to assess and train in a holistic way, where you can actually start tackling different sensory systems. To me, that’s a great addition to a treatment.

Interviewer: Excellent. Thank you so much Fernando. This has provided a lot of insight into how you’re approaching designing some of these training scenes, so we really appreciate it.

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