Jared Powell:
Welcome to the shoulder physio podcast, a podcast dedicated to exploring meaningful topics in musculoskeletal healthcare. I'm your host Jared Powell. Before we begin, the primary purpose of this podcast is to educate and inform the views expressed in this podcast by myself and any guests are information only do not constitute professional advice and are general in nature. If you act on the basis of any podcast episode, you should obtain specific advice from a qualified health professional before proceeding
Jared Powell:
Today's guest is Abby Tabor. Abby is a physiotherapist and pain researcher out of Bristol. England. Abby is a prolific researcher and is particularly interested in a concept called predictive processing or active inference. The brain has become no as a prediction machine, constantly making best guesses of sensations arising from the periphery to produce various experiences. Can this apply to pain as well? Stay tuned for Abby's perspective. It's one of my favorite conversations to date. This conversation was originally recorded in August, 2020 for my show on the shoulders of giants. Before we get into the nitty gritty of the conversation and for your information for the first time in two years, I am running my one day shoulder workshop in Sydney and Melbourne in may and June, 2022. Tickets are limited to 30 participants for each workshop. The course offers a complete distillation of the evidence based for shoulder pain management, equipping you with up to date, knowledge, techniques, and clinical reasoning skills that are clinically actionable. If this is something you are interested in, check the show notes for more information without any further delay. I bring to you my conversation with Abby Tabor.
Jared Powell:
Hi Abby. Thank you very much for joining me for a conversation about something that is, I think should be of great interest to physiotherapists. So thank you.
Abby Tarbor:
Hi, Jared. Yeah, thank you very much. It's a, yeah, it's a real pleasure to be chatting to you. So yeah, cheer for the invite.
Jared Powell:
No worries. We've all got a lot of time in, at the moment with this, with this pandemic, which we won't speak too much about. So these
Jared Powell:
Zoom
Jared Powell:
Conversations have come in good value for me. So I guess where I wanna start is, is who are you? What's, what's your background? We just discussed a moment ago that you were a physio, which I had no idea about. So we, we do have a little bit in common, but you've since ed into an, a illustrious research career. So a bit about you and your background.
Abby Tarbor:
Yeah. So yeah, as you say, like, I, I started off working as a physio in London and that does seem like a bit of a, a distant memory now, but I I'm, I sort of went and did a PhD which was very sort of, it was great for me. I worked with Lorimer Mosley, Nick Thacker. I spent some time in south Australia and yeah, that kind of stuffed me on the research route. Really. I came back to the UK and, and since then, I've, I've kind of been working in academia. So I'm currently a lecturer in rehabilitation at the University of Bath. I'm living in Bristol. Yeah. My work is really trying to look at particularly sort of theoretical models and how they apply to understanding the transition from acute experience to a persistent one. And yeah, basically trying to get a grip on, on how we understand those, those mechanisms from a theoretical perspective.
Jared Powell:
So why did you, why did you move from a promising physiotherapy career to a career in research? Did you have a, an existential crisis or, or what,
Abby Tarbor:
Yeah, something like that. I think I, I probably can blame Laura for that actually. I, I was like disillusion physio when I went to listen to him, talk at queen Mary's university and, and that was bit a game changer to me as it opened up the idea of, of what it was to be a physio. And, and how you could be a physio and ask questions and questions can lead to deep world of research. So, Laura,
Jared Powell:
I think he's, I think he's guilty for a number of career shifts. What do you mean physios can ask questions. We can't ask questions. We just have to stick with tradition and dogma and do it just because of the way it's been. Right. That's what, that's what isn't, isn't, isn't now based practice and evidence based medicine, which, which is funny, it's been around for obviously decades. But I feel like it's really taken off over the last 10 to 15 years, probably with the advent. I, I think social media's been powerful here in actually disseminating a lot of this stuff and obviously the internet and blah, blah, blah, blah. But I, I really feel like physios that are juncture at a really sort of critical point where we're all starting to ask questions and, and often, and I'm, I'm involved in teaching at university as well.
Jared Powell:
And we're still not gonna say too much, but we, we still teach things that perhaps may have been updated a little bit, you know, over time. And, and I, I struggle with that. There's a bit of a tension in between. How much do you actually teach to students in terms of how much uncertainty do you give them? Because a lot of stuff is uncertain or do you just say, oh, do this special test for the shoulder. And that will reveal a patho anatomic diagnosis, you know, so there's kind of that pull between, okay, we need to ask questions, but when do you ask them and at what point in your career, or do you just give it a couple of years after you practice for a bit? I dunno, obviously you teach as well. What do you, what do you think? Because we do have to sort of have some sort of answers for students, don't we?
Abby Tarbor:
Yeah, it's an uncomfortable, I guess, of having a, sort of a certain amount of, of definite that enables students and practitioners to have a a platform from, from which to practice. And, and I think that is important. I think it's, you know, and some of the teaching that I'm involved with is within a master physiotherapy program. And a lot, lot of that onus is, is on how, how do we feel comfortable with that discomfort of, of like actually our practice, isn't, it doesn't have to be pinned to a certain, certain flag and actually more, the skill is not necessarily in or wholly in the technique, but, but in, in the way that we apply that and the questions that we ask of, of, of ourselves as we apply our techniques and remaining open that there are multiple ways to achieve different outcomes.
Jared Powell:
Absolutely. So exactly this is, and this is something that of just submitted a, a paper on it's the mechanisms of an intervention, probably what you think they're doing. So if you apply strength in exercise to the shoulder or to the quadricep, whatever you want, that person's pain can become ameliorated, even if their strength doesn't increase. So what's the mechanism underlying applying resistant, you know what I mean? So there's this multifactorial interaction between how we think something works and how does work.
Abby Tarbor:
Yeah, I think that's the reality that we face in, in healthcare though, when you're, when you're dealing with people, these complex entities in an even more complex world than your intervention is, is just a small part of a, a much bigger picture. And it has the ability to spawn so many different interactions that can have positive. And I think being open to the idea that, that that is, is the case is yet
Jared Powell:
The important thing is I think is that we're not, we're not, I don't think we're taught enough that, so our clinical reasoning is still embedded in this biomedical model a hundred percent. And that, that is what I, I believe pretty much every single university course of physiotherapy teachers. And that's why you learn special tests. That's why you learn testing active range of motion with a goniometer. You know, that's, that's the cause of the pain because that's two degrees out versus the other side or a scapular dyskinesis, which is my interest. But, and then, and then, and then a couple of years out, we start hearing from Laura moley, or we start hearing from Peter O. Sullivan or other important voices in the field. And we're like, well, how does that equate with my deeply biomedical understanding of things? You know? So I do think we can be better at, at, at sort of teaching students, Hey, this, this is probably not too far wrong.
Jared Powell:
You can, if somebody comes in with shoulder pain and it hurts when they do that, and it, it they're a certain age group and they fell over the day before algorithmically statistically speaking. There's a chance that they probably have a, or, but when we speak about pain or when we speak about other more complex perceptual things, as, as you were saying before, we have to be, we have to think outside of a pure biomedical model. So I imagine like, how do you go in your, how do you go? So in your first person experience, how go explaining that to a bright eye student who wants to know what, what a positive test for, for this means for a kin's for example, show what,
Abby Tarbor:
Yeah, I mean, I I'll, I'll just come back to the previous point about sort of teaching within physio school. I think like I was in some ways lucky to have an education in physio that was, as you described largely by me medical, but in midway through that, we had this sort of this guy come in and talk about this. What, what seemed to us as this completely radical and off the wall. And that guy was mixed backer, and he kind of just introduced this whole sort of different world of understanding what pain constitutes. And it was completely at odds with most of the, the rest of the teaching. And it kind of stuck with me that we'd had. And, and, and then going into practice after that, you're dealing with patients that, that their number one sort of concern it is their, is their pain often.
Abby Tarbor:
And we had two lecture throughout the entirety of my undergraduate degree that focused on understanding what pain actually was, and we spent whole semesters understanding manual handling of, of the, of the shoulder. So it's kind of that, how, how do we, how do we reconcile that? And I think, you know, the, the question you asked is, is a poignant one. It's one that I'm, I'm trying to address within in the way that we structure our course, actually, rather than sort of maybe at the individual level. And, and I'm trying to structure the way in which our units are outlined. So this is maybe a bit, a bit boring and, and not so practical on a one to one level, but the idea that we can approach problems, whether they are traditionally bio biomedical and your example there is, or this is kind of like a clear cut biomedical model.
Abby Tarbor:
It works for that. But I guess part of what we're trying to do is, you know, we do have models that still accommodate the idea that there is a sort of a, a driving factor that is not wholly sort of at the, at the psychological level on social level and, and, and really integrating the idea that we can ACC who sort of injury based experiences of pain in the same model as, as of as pain experience, it seems wholly detached from, from injury. So I think it's, it's trying to approach it from a framework that gives us, gives us that leverage rather than having to jump between like this, this biomedical model to how do we reconcile the two UN under a model that, that gives us strength as a practitioner.
Jared Powell:
Yeah. And we're gonna, we're gonna get to what that, what that model might be in the moment, but before we get into the, to the nitty gritty at all, I have to ask you AOUS question, what book are you reading at the moment? And or what TV series are you watching?
Abby Tarbor:
Yeah, so, well, like these, these questions, I'm always like, I see them, I'm like, God, I really I'm actually reading a book,
Jared Powell:
Just
Abby Tarbor:
I'm reading a book. It's something that I trying to digest for a long time. And it's it's called dystopia by Carolyn steel. And it's just, it's, it's completely outside of the work that I do, which is nice to escape, but it's also something that's really interesting from a, just a, a world perspective. I, I guess Karen, steel's an architect and she's, she's writing about how food is really the center of, of everything, how we experience the world from food chains, all the way to our, our social social lives and how that has become wholly detached from how we get our food. So that detachment is, is crucial in, in socioeconomic divides in people as, as well as our health.
Jared Powell:
That's do pretty dense stuff. So I that's
Abby Tarbor:
So long to get through it. I've been reading it for about six months.
Jared Powell:
Yeah. I'm, I'm guilty of that. I've reading a book called behave by Robert Sapolsky at the moment it's taken me 18 months now since the first opened it. And it's, it's 800 pages. So, so just judge me. But man, I reread every page number of times. So it's not, it's not good nighttime. Well actually does put me to sleep pretty quickly. OK. Anyway, so, so thank you for revealing that I think that adds just adds a little bit of personality to these somewhat boring conversations. So let's get into the, the good stuff and stuff that I've, I came I've come across, or I've known you for, I've read a lot of your work and mostly has to do with these terms. And I'm gonna throw a few terms out there, active inference, BA inference, predictive processing, the Basian brain, blah, blah, blah, blah, blah, predictive processing stands out. Cause that's that's something that has really taken off in the field of physiotherapy, probably only within the last five. I know it's been around a lot longer in other, but is a leading voice in predict processing at the moment. I, I know you've worked with him as well. So could you just sort of briefly describe predictive processing or active inference if you like and how the two may relate and how does it apply to pain specifically?
Abby Tarbor:
Yeah, so I guess a good starting point, because I think, you know, we're at a point where these terms are, it is a bit like a forest trying to navigate through understanding what these different terms mean and, and how they've been taken in different research directions actually. And sort of, you know, starting with predictive processing, this it's really is a, a framework that, that it has its base and all of, all of these sort of terms that you've, you've mentioned, whether it's predictive coding predictive processing, sort of active inference, I sort grounded in a sort of statistical inference model mainly Basian inferences, which is essentially trying to describe probability. And, and, and how probability relates to all the way up to E experience. And so this is a bit of a starting point in my case with, with Laura, when I was trying to describe how the experience of pain in, in some of his work he'd done previously, can, can shift given different contexts, whether it's a different visual piece of information, different auditory cue, how, how does the experience of pain, how is that reshaped given the fact that we have access to more information and the sort of predictive processing framework really borrows from other perceptual, so largely vision and how people make sense of a world that is uncertain.
Abby Tarbor:
So the pieces of information that we have access to are uncertain, and we try and integrate pieces of information to increase the certainty with which we kind of know what what's happening. There's sort of important inversion in that process whereby the, those models of, of inference are really about not passively receiving stimuli, but actively seeking in information in order to make sense of try and make sense of what has caused the sensory piece of information to, to sort of be inferred in that way. So it's kinda a, it's a way of accommodating this element of uncertainty in our experiences. Our experiences are, are when we, when we experience them are, are, are very certain, we, we know we're experiencing pain with a hundred percent certainty. What this inference process tries to under underline that with is the idea that all perceptual experiences are based on incomplete information, and we are doing our best to make sense of that.
Jared Powell:
So this extends to all of our perceptions, this extends to vision, this extends to hearing extends to whatever else.
Abby Tarbor:
Yeah. So we, we can, we can apply this, this framework and, and it has been largely applied outside of the world of, of pain where why, why we try and understand, you know, how, how we basically make sense of a world. Why, why is the world such a certain place for us in the sense that actually we are, we are constantly dealing with information that isn't, isn't complete about the world. We, we kind of, we have to almost fill in the blanks with, with information from different sources in order to have that, that, that sort of coherent idea of what our body is and what our, what our world is.
Jared Powell:
Yeah. And that's the, the, what, what are sort of the vision is the one that, that is interesting to me because how the hell do we formulate vision based on photons hitting our retina, you know, or how, how, how do we formulate sounds distinct sounds that we know out of vibrations in your, in your yard. It's, it's a crazy thing to think about, right?
Abby Tarbor:
Yeah. And that process, you know, in, in, in historically, it's been considered sort of in a, in a modular way where you kind of have this transf of information in, in, in separate sort of vessels, so that they're kept separate. But what we know more about our experience is that they're holy multisensory and we integrate information to have a better idea about what what's go going on.
Jared Powell:
And so how does, and how do we then apply this to pain specifically, or how so, firstly, how do you think about pain? What's your, what's your Ted talk on pain and then how does predictive processing become integrated with, or how does it explain pain?
Abby Tarbor:
Yeah, I think, I think, I mean, this is, this is ongoing for me. I think, I think there are no I, this is something that I toy with on a, on a daily basis, trying to kind of adequately either define pain or, or understand pain from a, from this framework. I think it's an ongoing process to me, the, the key elements to it. I think that, that the framework helped draw out. And really this is appealing more to active inference than sort of predictive processing in many ways is that there is a blurring of the boundary between perception and action under these, these frameworks. They, they essentially work together in order to attempt to resolve discrepancies that we might encounter. And from that perspective, I come back to pain. The experience of pain sits between, between this boundary of perception and action.
Abby Tarbor:
And I like to think about it as something that is something that we do in, in a process that, that aims to protect ourself from future harm. And I think those two things are really important that come out of the, this, this predictive framework. One on that we have something that is not wholly perceptual or wholly an output of the current state of affairs, but rather something that is orientated towards the future so that we are attempting to protect ourselves from future harm rather than the current state. The current state informs it, but we're protecting from, from current harm. And, and that really is about action in the future. So pain is just sort tied to this action within, within the future realm.
Jared Powell:
Yeah. So pain is pain is it's not just something that happens to us. It's not a bottom up. It's not, perhaps it's not a passive experience. It's something that's sort of embedded within action and prompts us to perhaps do something or safety seeking behavior, or to stop that happening again in the future. Is that, is that the crux of what you're trying to say? Yeah.
Abby Tarbor:
I think probably summarize better than, than idea this, this idea that, that pain is something that we, we do we experience in order to prevent future harm like this, this change in action in order to maintain or, or resolve oddly integrity.
Jared Powell:
Awesome. So that has a lot of sort of implications for physiotherapy practice. I think where we, that's, how we need to conceptualize pain. And we need to sort of understand why someone who has a sore knee doesn't wanna do a squat, you know, because at the very granular level that is going again, what their system is telling them to do, right? So we need to come at it from a, from a different sort of way. And then we also need to not further sensitized that fear perhaps of you, can't below 90 degrees, otherwise you're gonna squash your meniscus and you're gonna tear it, you know, so that, so I think for having an understanding of pain in that manner really will directly inform our practice even just based, based on that definition without even going any further into it. So thank you. That's, that's a really cool way of thinking about it.
Abby Tarbor:
No, no, just, yeah. It's the idea of that definition is, is trying to be helpful. Something that, that, that is evolving in, in my mind. And, and yeah, like, like you say, trying to team that with, with the way that we think about pain and, and shifting that in terms of actually, if someone's inferring, the, the situation that they're put in is threatening, then their interpretation of that situation situation gonna be very different to somebody who, who isn't yeah.
Jared Powell:
Hundred percent and that will, that will sort of dictate the progression of their symptoms and how we need to interact with them as well. So this is the individual in individuality of pain, right. And I thought we're gonna speak about this a bit later on where pain can get stuck in some again, to, to borrow one of your terms. So if we just sort of linger with predictive processing for a little bit longer what's so what are the constituent components of predicted processing? What's a prediction error. What happens when a prediction error arises? What are what's the what's the nuts and bolts of it?
Abby Tarbor:
Yeah. So I guess if breaking it, breaking it down, predictive processing is constitutes this idea that we generate prediction of the consequences of our actions. So it might be app preceptive predictions in terms of where our body is in space or where it will be in space. If we conduct a particular action like reaching for a cup it, it also constitutes predictions about the, the other sensations associated with that. So the visual input of where our arm will be the tactile sensations associated with, with the reach, those sorts of things. So we sort of have these, these predictions about how our body will behave when we act. The prediction era that you talk about in prediction processing is, is sort of the discrepancy between those predictions that we, we hold and what actually occurs. And so you have this sort of feedback in, in the, in the sense that when you do reach the cup, the, there are piece of information that in where your arm is in space and the prediction error is basically the discrepancy between what you predicted and where, where the arm is as it, as it reaches.
Abby Tarbor:
And you're constantly sort of up updating that the process of, of in predicted processing is that you're constantly updating that prediction potentially on one side. So say that the cough is, or your arm is jogged. You are updating where the arm is in space and, and reconciling that prediction error. So the predict, the, the information that's coming from bottom up is, is, is more matched to the predictions. The other side of the, the sort of coin, if you like in reconciling prediction, error is, is altering your rack. So it could be that you, you change the way that you act in order to meet the expectations of your, your prediction. So sort of two different ways in which prediction error is, is resolved. And the idea and of predictive processing is that your aim is to minimize prediction error in order to pursue of long coherent behavior in an environment. So you become better essentially at predicting how youll interact with your environment and that the reduction prediction error, or in active inference long surprise or free energy,
Jared Powell:
The, that you mentioned for energy. I was just listening to something by Carl Friton and I'm gonna have to listen about about a million times, but anyway, so if we talk, so if I just try and encapsulate what you said, so we have a prediction, or we have a generative model of how we think something is to pan out, or, or what are the consequences of our sensations, for example. And then we constantly comparing that to sensory information or, or sort of bottom up information that we're constantly receiving. So, as you said, protive interceptive and interceptive, is that
Abby Tarbor:
How you, I say, and I guess the other point is that this, this happens across a sort of a neuro hierarchy, if you will. So it could be that these are very quickly resolve in terms of, you know, reflex action. So the spinal cold level, it could be that it's propagated higher up the hierarchy where these prediction areas are having to be resolved with more high, high level sort of scheme. So updating the predictions of, of how our body moves, and this is something that's an ongoing learning process. And it happens as we learn a new skill just, it happens as, as we injure ourselves and have to better accommodate what, what the body is, is capable of.
Jared Powell:
So all of these, all these prediction errors, they don't just to clear this up for everyone. They, they don't reach consciousness do that.
Abby Tarbor:
You haven't got prediction. Error is a, is a, is a, is a term that essentially describes how in information is put past within the nervous system. It's not something that you would consciously be aware of. It's something that's, that's part of a framework that helps to describe how information may or may not be passed through our, our system essentially.
Jared Powell:
Yeah. Cool. Okay. So I think that explains a, a prediction error, and then there's two ways that we can actually reconcile perhaps a prediction error. We can either update our model, or we can act on the environment to change the, the sensation or the, the stimulus. Is that, is that
Abby Tarbor:
Correct? That's it? So you've got some, two sides of the same coin where you're going. Yep. Do I do I need to update my model of, of how my body behaves in a certain context and that constitutes learning or do I change my behavior to better reflect my prediction within this environment? And you could, could give an example of sort of walking down a cobble street at night where your, your behavior usually walking down that street would be to just power on, through, and get, get home. But given that the low light, and there are Cobbs, you're having to update your behavior in order, in order to better navigate an environment that's giving you lots of other sensory information. So a crude example, I guess it is worth mentioning at this point, that a key element of that is a part of the framework is, is known as precision waiting.
Abby Tarbor:
And this concept of precision waiting is, is crucial to understanding how information is pass through the hierarchy and how it is used to update certain update, the generative model and, and, and the predictions that we then make go in in the future. And that sort of precision can be talked about assigned to information. And that may be information that, that is salient in a particular environment. So given the example of walking down a dark street, suddenly vision, which is usually relatively precise and, and, and therefore carries good deal of weight through the hierarchy becomes less reliable. And so your so system tries to adjust for that increasing the precision associated with say the protive information of the ankle joint, for example. So, so you are knowing where your body is in, in space and that's informing perhaps greater. And, and yeah, that's just just one example.
Jared Powell:
Yeah, no, that's the, the concept of precision. I think we're gonna get to a little bit as well when it applies to, to pain. And so how some signals or some information reaching the brain can be given additional weighting over other competing stimuli, either in the environment or in the, in the body itself. Maybe this is a good time to touch on that. So, so what, what, what's the, what's the relationship between precision of a signal and perhaps the development of persistent pain or persistent pain presentation? What, what relevance does the precision of a signal have there and how may I actually impact a physiotherapist clinical practice?
Abby Tarbor:
OK. So those are two pretty, relatively w Ws of, of questions, but I'll, I'll try the, the first bit of that talking about how precision might lead to persistence and a sort of stickiness in experience. And, and you say that you borrow my term and I'm borrow borrowing Chris Olson actually. So he he's thanks for that, but, but the, the idea that we have this precision in order to sort of attune to relevant information, so in information is not just of received or, or sought in, in equal measure. We, we are able to attune given the different environment so that most relevant information is, is given greater gain. And this is a wholly adaptive process, and it allows us to be very efficient in our environment, taking information that matters to us most in line with our desires and goals and using it to drive and, and, and help coherent behavior, what I'm posing or what, what we are posing under the sort of predictive processing or active inference framework is that this, this sort of model and the, and the way that we navigate the world in this way, whilst adaptive and can, can be somewhat, it can be a little bit vulnerable when it comes to particular interactions that happen either very, very serious interactions or repetitive interactions in, in your life.
Abby Tarbor:
And I guess what this speaks to is having a prediction that our body is under threat, for example. So this might be sort of the integrity of your body threatened through injury. It might be threat within the external environment. It drives defensive behavior, and that is part from an adaptive process that enables us to either recover or avoid that threat. However, this is a very salient position to be in. We, we want to sure that we don't venture out when we are potentially threatened. So we hold this position. And something that we were talking about beforehand is that there is this trade off then as to when we start exploring again. And for most people, this is quite a sort of intuitive process of, okay, say that I've perhaps rolled on my ankle. And my initial reaction is to withdraw my foot and sub hop around for a little bit in ensuring that I'm not creating future damage by weight bearing on it.
Abby Tarbor:
And then gradually over time, we'll start wiggling our ankle and start to get exploring the concept of well what's going on in my body. And how does that react to the world? But as you say, in, in some people that sort of high, highly precise prediction of, of sort of threat or loss of bodily integrity, doesn't seem to kind of, it is never overridden and potentially become stuck. And the sort of difficulty in that situation is that we have a system that's highly adaptive to to allow that, to continue. It almost enters this vicious cycle of if we're predicting that potentially there's a threat to our bodily integrity. We are more likely to seek information that kind of confirms that or assign precision to information that potentially confirms that. So we are caught within this cycle of reinforcing the prediction, because we have access to information that that might confirm.
Abby Tarbor:
And we are also downregulating information that might serve to override or alter that prediction. In those precision terms, we're assigning high precision to information that's relevant to potential threat, whether that be seeing a staircase ahead of us. And that's something that we're gonna have to climb with an, that we feel is, is not able to accommodate that. It might be the app percept of information associated with where the ankle is in space. It might be ongoing, no deceptive cues that tell us about the, the ankle as well. So all of these sort multisensory cues are being assigned highly precise or assigned high precision and our prediction of threat and continuing that prediction rather than opening up and broadening our idea of, of what's constituting, what, what the is doing and what our body's doing and what broadly, what the environment's doing, we're sort of ignoring or downregulating that, that
Jared Powell:
Great job so
Abby Tarbor:
That
Jared Powell:
I try and I try and digest that. So the, the thing that really stood out there for me was this decoupling of the experience of pain and perhaps the sensory input, or if we're gonna talk about pain, no deception. So this, this, this prediction, or this hypothesis, or this model of pain can, can persist, and that can become quite removed from the actual nociceptive information, perhaps, which it may or may not even be experiencing. It may, it may still be a little bit of no receptive activity, but it's not certainly it shouldn't that, that, that relationship seems quite disparate. So, yeah, so that, that is because of this precision aspect where perhaps that person, for whatever reason, and there might be some psychological factors that play there, or some sociocultural factors as well gives high precision input from only the aspects of their system that confirm their prediction to minimize their prediction error. Is this, is that at all?
Abby Tarbor:
That's, that's a really good point. I think you know, to, to broaden this idea that we, we not only have this capacity to detach from this sort of stimulus re response notion of, of experience within this model, but also to broad, to this, this concept of, okay, what have previously been considered highly psychological factors, such as anxiety and catastrophizing, how that plays a role in, in the underlying physiology of, of the, the body, whether in injury or not in injury and the broader social cultural aspects of the, sort of the context of our experiences of pain. And that can speak to our, our sort of individual history, as well as our evolutionary history over time. And it could be, you know, part of this predictive model is informed by the past, and that could be the past of the individual. So particular circumstances that they found themselves in and how that has, has left them as well as our evolutionary past in terms of our, our underlying phenotypes, our expectations of, of our experiences and, and what they, what purpose they so helps to broaden out the concept of, of decoupling as you, you say, from this idea of, of injury, and actually thinking about putting it within a much, much bigger context of experience that is not just linked to the moment, but is uniquely informed by the past relevant to the, the present and then towards the future
Jared Powell:
That's. So I think, and we, we talked, talked about this a moment ago, and I think that really encapsulates everything within the bio psychosocial model that we're all trying to practice and apply, but which mostly gets divided into biological versus psychosocial. And I think this is where I'm attracted to predictive processing. Cause I think it, within the model itself, you, you almost can't decouple any aspect of that. It's all intrinsically connected to it. So I think this is where predictive processing should have some value and, and utility for physiotherapist. Do you agree with that?
Abby Tarbor:
Yeah, completely. I think even, and, and this is something that we discussed as, as well, even at the descriptive level of predictive processing. I think it gives us a, a lot of, we mentioned platform before, is this sort of like a, a certain element of certainty of as to how to describe these things fitting together without having to separate them into their sort of modules and then somewhat clumsily overlapping them and clunking them back together. Again, I think from the predictive perspective, all of this stuff has evolved together over time and, and in order to make sense of it, we, we can't separate each aspect and treat each aspect of it as a single entity. It's, it's about trying to use this framework as, as a, as a, as a sort of descriptor that enables us to treat them as yeah, completely coupled throughout.
Jared Powell:
And so I'm gonna try and relate this to, to physiotherapy as, as, as best I can. So if we have a, a sort of real world example, perhaps where I'm gonna do the shoulder, cause that's, that's, what is all about? So if you, you AB up to your shoulder to 90 degrees, that's a pain lock sign that has historically meant subacromial impingement or subacromial bursitis, or some sort of rotated pathology is causing pain there. How I'm trying to think about it a little bit is how can predictive processing be applied that, that movement and what I've experimented with a little bit is altering the position. So you can do it in sideline position. And that that movement may get less probably because you are reducing the load going through the shoulder, just with the interaction with gravity, any change in the context a little bit as well.
Jared Powell:
So, so the brain may not have a precise model of that particular movement in that position, perhaps or you, there's a number of other ways in which you can manipulate any number of internal, external variables to change the, the perception or the experience of pain that, yeah. So, so that has historically been looked at as that's expectancy violation, right? So that, and that's more in this, I don't even know what model that's kind of within grant exposure, I guess, where you, you try and violate somebody's expectations in order to maximize learning. I think predictive processing captures that as well. And this is again in why I'm so drawn to it, because it, it captures psychosocial elements, biological notice of developments, and also captures this sort of greater exposure expectancy violation kind of model thing as well. So, so this is, so this is where it can have real practical implications and you can do the same thing for a squat by manipulating any form of variable there, in terms of changing your hip angle or your knee angle or, or whatever you wanna do. Do you wanna add anything to that?
Abby Tarbor:
And I think, I think it's really nice to have, have that example to, to ground us with, cause I think it comes really easy to become quite abstracted from the reality with these frameworks and often it's a bit of a dense language to navigate through. So yeah, I really like that idea of how processing can kind of absorb some of the things that we are already practicing as physios. And it, it kind of offers an opportunity to not only link things together, but hopefully set it within a, a deeper understanding of, of why that might be successful. And I like it in terms of, you mentioned earlier about distraction, and I think in some ways the use of distractions become this sort of whether we're doing it within physiotherapy or whether we're doing it sort of experimentally within sort of virtual reality and, and things like that.
Abby Tarbor:
I think what predictive processing offers is this idea that actually distraction isn't necessarily the sort of feel, feel, and end all of, of, of what we're trying to create here. What we're, what we're trying to look at is understanding how, when somebody's experiencing pain, they tend to narrow the way in which they explore world in order to protect themselves. But in, so doing, they're creating a world that is wholly coupled with, with painful experience. And part of our role of, of, of physios is trying to introduce through action often this idea that we can start to broaden this narrow view and, and this precision associated with, with potential threats, by providing other pieces of information, to help, to challenge that prediction. And yeah, this, this constitutes the sort of psychological realm when we're talking about conducting rehabilitation in, in, in people that might be highly anxious in particular stances, as well as looking at, at changing the position of the body. So people can like your example of lying down and, and, and doing abduction. Like, can we, can we alter where the body is in space in order to provide information that is not fitting in with the prediction of
Jared Powell:
Yeah. And I think, I, I think that's, so that's kind of captured within something which we all intuitively kind of do, which is symptom modification in, in physiotherapy anyway, where you find something that's painful, you do an intervention and then you kind of reassess it. And it's classic in the shoulder with the shoulder symptom modification, where if somebody has pain reflection, then you perhaps alter the position of the scapula, or you get them to grip something to so put external low, which is meant to activate cuff better. And the pain goes away the same thing with various techniques in the back where you try and alter the perception of pain. But I think underpinning all of that is this kind of predictive processing. And we're not, I don't think we're actually fundamentally changing anything in the physical level. Often when we do that, we're just providing some form of different input or different context to change that person's pain experience.
Jared Powell:
And I think this is where we often get bogged down in physical therapy and in the biomedical model in general, where we think that the intervention we provide due to solely sort of physical responses or by loss responses that we can see and measure, you know, it's due to increased strength or it's due to increased capacity in the tendon, or it's due to better movement of the scapula or whatever. But underneath all of that, we have to accept that there's this, there's this multidimensional nature to it that we're, we're trying to reconcile it every millisecond or every, every minute of the day.
Abby Tarbor:
Yeah, I think there's, there's, there's so much in that, in the sense that, you know, we, we are, we actively seek seek evidence as, as, as people we're trying, we're trying to find out what's, what's going on with we're, we're seeking to confirm our hypotheses often, not just a scientist, but as, as sort of, as people trying to work out what's happening. And so providing people with evidence confirmatory or disco confirmatory is, is part of, of how we go about our lives. But I think you are right into terms of that realization of, we, we think we are controlling a certain aspect of somebody's care. We're naturally, I mean, the actual fact we're, we are, we're not we're part of that care, but we're, we're treating a complex entity, which is then part of an even more complex entity in, in, in the world and our interventions or your interventions are, are part of something that could be interpreted wholly differently in different, in different individuals and in different sort sociocultural environments.
Abby Tarbor:
And I think that's the other, the other thing that active imprint and predictive processing perhaps offer is, is this sort of look at bringing in with this grounding in evolutionary biology, where we consider experience in the modern day sort of as, as part of an involved being as, as humans, most of our evolution has, has occurred in a completely different environment than we find ourselves in today. And I think sometimes clash of the environment that we've essentially created for ourselves versus the environment that we adapted to over time means that our processes in order to make sense of experiences often have this fallout of mismatch. And, and it's very difficult to reconcile even though that adaptive process for most people works really well, but we're also seeing is this higher, like this massive increase in persistent symptoms in people, whether it, whether it be related to allergy, whether it be fatigue, pain itch bodily sensations that seem to persist.
Abby Tarbor:
And I think that that speaks to the larger picture of where human beings evolved over long of time in an environment that doesn't reflect the environment that we're in now. And we're trying to make sense of that with a system that has been developed over a period of time outside of that environment. And that's, that's key and maybe, maybe just taking the pressure off a little bit in terms of what is the role of the therapist here. There certainly is a role, but I also see healthcare is something that is much broader than it's currently thought of. You know, where is, where is the healthcare in the design of our streets, the design of our houses, our understanding of how we commute to work, how we work, all of those things that pay into this picture of how our bodies should be acting.
Abby Tarbor:
And yet we're, then we're treating people that sort of fall out of this system and then put them back into the system that may be causing the problem in the first place. So it's, I think it enables us the scope, not only as practitioners to have real practical input at the individual level, but I think it also enables to have this real big question as to we have the power more than ever before to have control over our environment, the way that we design them. And yet, are we designing them for good or for bad? I think, I think that's a, a relevant question.
Jared Powell:
Yeah. Wow. Okay. That's got real meta there. Real, real quick answer. I need to go online now to, to think about all these things. Thanks for ruining my sleep tonight. I think actually I think that's a, probably a good place to, to end that's, there's so much to, to consider, but I think if we wrap up the predictive processing element of it, what's the future, what a future with this, what's how what's going on in, in research land that you have access to, or that you have your ear on the street to what's. Is there, is there a lot happening in this space at the moment in, in sort of healthcare or is it sort of still within these cognitive science fields or what's going on?
Abby Tarbor:
Yes, I think, you know, for, for me, my experience of it at the moment is that it probably is situated predominantly within the cognitive sciences, much influence neuroscience philosophy and, and making sense of largely speaking in the realm of diagnosed clinical conditions, usually at the, of relatively extreme end of the, the spectrum. So things are like schizophrenia and autism, where it's a well, a pretty well defined clinical condition. I think what, what, where we find ourselves in, in pain is that we have a situation that is an experience that is ubiquitous and something that is part of normal life. And yet also this, this sort of other element of pain that is, that is wholly destructive and impacts people's lives negatively. And I think from a research perspective, I can sort of speak to myself. I think things are moving in this direction within, within pain where we are at probably at the point at which this is some of the work that I'm doing at the moment, hoping to build descriptive models that adequately translates hypotheses.
Abby Tarbor:
And I'm working on a project at the moment, that's doing that in Phantom limb pain, another relatively extreme incidents of, of pain. But my hope is that we can develop a model there that translates more broadly across pain experience. In this circumstance, what I'm trying to do is take an example of where pain exists, where action is impossible. And, and, and so how, how does, how does that relate to the experience of pain where action is restricted and, and, and how that, how that breaks down. So I think where we're at is, is of building appropriate model models that allow this then to be tested. So testable predictions in clinical populations and that, that is moving forward. There's work being done in, in interception, Lisa Barrett Mika a leading some of that Sarah Garing call a Seth all doing work.
Abby Tarbor:
That's really trying to look at how it translates in bot in bodily experiences using experimental paradigm. So it's, it's getting there. I think it, it's, it's still a work in progress and particularly in pain where we have an experience that's both every day, but also not in, in, in terms of the clinical assistance. So, so yeah, to me, it's an exciting framework at the descriptive level for clinicians. I think it gets more exciting as we are, we're researching how that translates into underlying bio psychosocial mechanisms, and then feeding that back into clinical practice it's, it's crucial.
Jared Powell:
That's really exciting actually. I'll, I'll point to I'll point people to some of your work. So the pain unstuck paper, and I'll sort of put this up for people is a really good paper, this this BA in learning one, which I've just been over Basian learning models of pain are call to action, fantastic favor, and then pain, a statistical account, which you did with Lomo M is a, is a really cool place, I think, for people to start. But yeah, so I've sort of, there's obviously a lot of reading to be done. It's sort of hard to kind of, it's hard to encapsulate a lot of stuff. There is deep mathematics and physics underpinning all of this as well, but I think it's, if you can understand it from a sort of framework, qualitative perspective, still think you can use it in your practice and have it underpin your clinical reason.
Abby Tarbor:
Yeah. Or I just wanna say, thank you. You've been very kind to me, so thank you. And I think if there's, if there are physios or other clinicians that are in interested in learning a bit more, I, I think it's, it's difficult to capture everything in a, in a conversation. So if, if there are, there are follow up to this, then by all, all means, get in touch. I think it's a conversation worth having in the world of physio. And the more that we talk about it, I, I think the, the greater, my understanding as to how this translate clinically will be. And I, I think that's key.
Jared Powell:
Thank you for listening to this episode of the shoulder physio podcast with Abby teal in the time that has lapsed since August, 2020, when we recorded this conversation, the content discussed is still accurate. And up to date, if you want more information about today's episode, check out our show notes at www dot shoulder, physio.com. If you liked what you heard today, don't forget to follow and subscribe on your podcast player of choice and leave a rating or review. It really helps the show reach more people. Thanks for listening. I'll chat to you. Soon. The shoulder physio podcast would like to acknowledge that this episode was recorded from the lands of the Yu Uganda bar people. I also acknowledged the traditional custodians of the lands on which each of you are living, learning and working from every day. I pay my respects to elders past, present and emerging and celebrate the diversity of AB original and Torres Strait Islander peoples and their ongoing cultures and connections to the lands and waters of Australia.
