Welcome back to the Pain Science Podcast with Anna Waisman

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Welcome to the Pain Science Education Podcast, where we discuss ways to treat and reverse persistent pain. I’m your host, Dr. Joe Tatta, a licensed physical therapist and founder of the Integrative Pain Science Institute, where we train practitioners on whole person pain care. This podcast also serves as a public health campaign to support those living with chronic pain. This podcast is for informational purposes only, and it’s not intended to be a substitute for professional medical advice. Hey there, friend. Welcome to this week’s episode of the Pain Science Education Podcast. Today, we’re exploring the connection between memory and pain. To guide us through this emerging area of research, I’m joined by Anna Weissman, a doctoral student in clinical psychology at York University in Canada. Anna’s research focuses on memory and includes developing memory-based interventions to treat chronic pain and further understand how our brains process painful memories. In today’s episode, we discuss how past experiences shape the way we perceive pain, what the science reveals about the role of memory and chronic pain and the role of emotion in shaping painful memories. If you’re curious about how our memories might hold the key to understanding pain and potentially even reducing it, then this episode is for you. OK, without further ado, let’s begin and let’s meet Anna Weissman. Hi there, Anna. Thanks for joining me this week on the Pain Science Education podcast.

Hi, Joe. Thanks for having me. It’s great to be here.

I’m excited to speak to you. We have a couple of hundred episodes under our belt. And the one topic we really haven’t started to dig into is memory. So often we talk about the brain and the nervous system and how our experiences of life and pain are encoded. but we really haven’t started to touch on really what that means to us, right? So, what does the science say? What do we know? Where are we going? And from that, what little tidbits can we apply to clinical practice? I was excited to come across some of your early career research. And I can think of probably a good place to start is as a psychology student and a major, how’d you become interested in looking at memory, but specifically looking at memory in the context of chronic pain?

Yeah, absolutely. So before I started my graduate studies, so I’m currently a graduate student in clinical psychology and neuropsychology. I worked on research studying spatial and autobiographical memory, or memory for personal experiences from our past, at the Rotman Research Institute at Baycrest Hospital in Toronto. under the mentorship of some really excellent memory researchers, so Dr. Shana Rosenbaum and Morris Moscovich. During that time, I had the opportunity to work closely with individuals who had memory impairment, doing various sorts of cognitive testing with them. One thing that happened to stand out to me was that when I would take these individuals’ health histories as part of the studies that I was working on, many of them would report having chronic pain among other sorts of health issues. And so, this was kind of an early experience that piqued my curiosity and made me wonder whether there might be a deeper connection between memory and pain that hadn’t been fully explored yet. So, I kind of saw this as an opportunity to, you know, apply some of my background in memory research to the field of pain, thinking that maybe there would be a way to integrate the two disciplines. So yeah, I would say this early exposure to memory research combined with sort of the observation of chronic pain coinciding with memory issues eventually led me to pursue my graduate studies.

So, give us a window into what we currently know about memory and pain. There’s lots of different types of memory, And of course, lots of different types of chronic pain syndromes. But what does the literature kind of tell us currently?

Yeah, so if we sort of take a step back and look at the study of memory and pain, we’ll see that the term pain memory first came up in a human context around the 90s. So, there was a paper published by the great Canadian pain researcher Ronald Melsack and my PhD supervisor, Joel Katz, where they use the term pain memory to refer to phantom limb pains, which are pains that individuals feel in a limb after it’s been amputated. And in this paper, they distinguish between what they refer to as the somatosensory component of the pain memory, which is sort of like the unconscious type of memory for pain that’s felt in the body. And then the cognitive component of a pain memory, which would be the conscious recollection of a pain. And it’s that latter one that I happen to be more interested in. So since around the time that that paper was published, Most of the research in the field looking at memory and pain has largely focused on looking at the accuracy, so to speak, of individuals’ memories for painful experiences, mostly based on self-report measures for things like pain intensity, pain affect, and anxiety, where the idea has been to compare individuals’ ratings at the time of the painful event to the ratings they provide for the pain, as it’s recalled at a later time. And so, you know, while this approach might get at the memory sort of sensory and affective qualities, it doesn’t fully capture what it’s like to actually re-experience a painful event in one’s memory. Right? So, in other words, kind of like the phenomenology of remembering that painful event. So, what is it like to actually be remembering a painful experience that you had? And This is where autobiographical memory comes in. And that’s the topic that I’m particularly interested in in my research. So autobiographical memory is what’s called a declarative memory system that’s made up of something called episodic memory, which is memory for specific events from one’s personal past, and semantic memory, which is more about general knowledge about ourselves and the world and episodic memory is what we’re really thinking about when we refer to this so-called re-experiencing of a painful event in memory. So, the famous memory researcher, Endel Tulving, described episodic memory as involving what he called auto auto-noetic consciousness. So, it’s basically this human ability to mentally time travel or project ourselves across time into the past to re-experience specific events and then also into the future to sort of pre-experience events that haven’t happened yet. And so, it’s only very recently that a handful of studies have started to investigate this aspect of autobiographical memory in individuals with chronic pain. Largely looking at sort of pain-related content, and then also something known as spatiotemporal specificity, which is basically how specific a memory is to a particular time and place. In my own research, we’ve also been looking at other dimensions of autobiographical memory, like how rich or perceptually vivid the memory is. And so, kind of coming back to this idea of spatiotemporal specificity, Interestingly, what most of these recent studies have been finding is that individuals with chronic pain tend to have what’s known as an over-general memory bias. So, this means that the memories that they tend to retrieve are more generalized, where they lack specific events tied to a particular time and place. I can give an example of what this could look like. So, for example, instead of recalling a memory like last January on the first Sunday of the month, I injured my arm, and the pain was throbbing. They might say something, you know, individuals with chronic pain might say something like, whenever I play sports, my legs ache the next day. So that second memory has a sort of repeated nature to it that isn’t specific to any particular time or place. And this over general memory bias is pretty well established in the psychological literature in conditions like depression and post traumatic stress disorder. And so now we’re starting to see that individuals with chronic pain also tend to exhibit this type of bias. And so, kind of building on some of those findings, for my master’s work, my master’s thesis, we conducted a prospective longitudinal study where we found that this over-general memory bias for memories specifically related to pain was a risk factor for individuals developing chronic pain up to one year after undergoing surgery. So those are some of the findings kind of from looking at the memory and the cognitive behavioral side of things.

And I will link to all of your research papers in the show notes. Of course, everyone can find them. over on the page at the Integrative Pain Science Institute on the particular podcast. And you’ll probably find it on my social media handles as well. But I want to start to kind of unpack some of what we just what you just presented to us, because there’s a wealth of previous knowledge, I think, baked into that. And then, of course, your own research that you started to explore and investigate. Let’s come to start super basic for people, right? Because even even the practitioners who are listening are probably thinking, well, what did I learn about memory in school? Right. It’s been a long time. So, what, what part of the brain are we talking about here?

Yeah. So that’s a great question. So when we’re thinking about autobiographical memory and especially episodic memories, so that memory for specific, you know, vivid perceptual memories for events from our lives, we’re talking about the hippocampus and the surrounding area known as the medial temporal lobe. And so, what’s interesting is that some of these findings that I just described related to this over general memory bias in chronic pain have actually been implicating the hippocampus in the condition. So, individuals with chronic pain have been observed to have certain changes to their hippocampus, including structural changes as well as functional changes with other brain regions. For example, there’s been some research showing that the connection between the anterior part of the hippocampus and what’s known as the medial prefrontal cortex are weaker in chronic pain. The medial prefrontal cortex is a brain region that’s involved in various different functions. But one of those includes constructing or being able to locate an episodic memory when we’re retrieving memories from our lives. And so, yeah, changes in how these areas communicate with each other seems to play a role in the transition from acute to chronic pain and might potentially be related to why people with chronic pain retrieve more generalized memories. But that’s not something that’s been investigated yet. And that’s something that I’m, I’m starting to look out with my research.

Yeah, really interesting. So, in our brain, we have this memory storage unit called the hippocampus, which stores our memories. And then we have this kind of front part of our brain, the prefrontal cortex, which can retrieve those memories and make sense out of them when we need to, to have them. For example, putting my hand on a hot stove, I have a memory that that hurts. and that frontal part of my brain can help me if I find myself in the same situation again and make sense of what could happen or what’s about to happen or what kind of is happening. So, you mentioned the word autobiographical memory, right? Big kind of long word. So autobiographical memory to me, I always try to make things simple for people, means kind of what I remember about myself and how those memories are starting to shape in probably some way, my sense of self.

Is that correct? Definitely. So autobiographical memory is very closely intertwined with our sense of self and sort of how we relate to other people, to the world. Even our ability to imagine the future has been shown to be dependent on episodic memory processes, and even activates the same networks in the brain. So, the two are definitely very closely intertwined. There’s also something that I would love to speak more about and is sort of lays the foundation for how I’ve been thinking about what’s driving this bias, but something known as memory schemas. And that’s, that’s also something that can be thought of as being quite closely linked to our sense of self as well.

So, tell us what a schema is. We’ve heard these concepts in the world of psychology, but I guess what is a schema and how does that start to relate to pain?

Yeah, absolutely. So. There’s many different ways of defining the schema, and I think if you look at especially in psychology, you know, when you look at depression, it’s talked about one way, but when we’re talking about race schemas and sort of what we mean in memory field, these are usually defined as dynamic knowledge structures that are regulated by the medial prefrontal cortex in connection with the hippocampus, so the brain region that’s responsible for memory. And what they do is they sort of guide the way that we encode and retrieve information in our memory, which ultimately has implications for how we perceive and act in the world. So, you know, when you encode new information, one thing that these schemas do is they direct that incoming information such that it can either fit into existing schemas that you already have, or alternatively, the schema can sort of adapt to be able to incorporate that new incoming information. So how does that kind of relate to chronic pain, right? Like what are the implications of this? So, the way that I’ve been thinking about the role of autobiographical memory and especially schemas in chronic pain are that for people who are repeatedly experiencing or exposed to pain in their day-to-day life, their pain kind of situates them in an environment that is in many ways dominated by pain, right? Like where they are sort of continuously forming these almost negative emotional associations. And so, as a result, they are potentially more likely to continue to experience pain-related events and encode these events into their memories, while at the same time being less likely to have access to and encode events that are not related to pain, and so to speak, more adaptive experiences. And so essentially, you can think of this, you know, for thinking along the lines of this framework, this sort of creates a situation where these memories start to focus more and more on pain, and less and less on other aspects of an individual’s life. And over time, what happens is this leads to the formation of what we refer to as the pain schema. So, sort of like these mental templates that revolve around pain and how it impacts our lives. And the more that someone experiences pain, the more these schemas become reinforced. And they sort of start to shape how the individual interprets new experiences. So, to give it, Yeah, and maybe I can provide an example of what that can look like. So, you know, if someone has a schema that associates certain movements with pain, they might avoid those movements even after the pain has gone away. And so that avoidance can act to sort of increase pain disability and continue to reinforce that pain schema.

Yeah, and these building schemas, in a way, are these in some way, a belief system around what the pain means to the person’s life, what it means to their self-concept, what it means to them functioning in their environment, so to speak, right?

Exactly. So, sort of what you might see happening over time is that these pain schemas become more rigid. And just like you were saying, they can start to impact someone’s sense of self, where the person might start to see themselves as being defined by pain, right? And as a result, these sort of pain oriented self-concepts can affect how people and for the future, the sorts of decisions that they make, the sorts of goals that they set for themselves, and ultimately, their overall day to day functioning, as they kind of continue to act in ways that match these schemas that they’ve developed.

Yeah. And the scheme has kind of become intertwined with other schemes that we might have from previous life experiences as well. Is that correct?

Yeah. So, you know, there isn’t like necessarily just one type of schema that an individual has. We have many different types of schemas and the experiences that we have sort of act to either reinforce those pre-existing schemas or alternatively to modify them. And that’s something that can actually, you know, maybe we’ll get into this a little later, but can be leveraged for thinking about treatment is how do we modify these schemas to help people, and get them further along in their path to recovery from chronic pain.

I definitely want to talk about that. So just to kind of maybe we can catch people up. So, obviously we’re talking about memory. We have a part of our brain called the hippocampus, which stores memory. And then we have this other part of our brain, the prefrontal cortex, which is kind of making decisions about our life and laying down these schemas or beliefs about ourselves, our world, and of course, about what pain means to ourselves. You mentioned affectives. Every time someone says that word, I just think emotion, emotional, right? What are emotions? or what is the role of emotions in these pain memories and pain related schemas?

Yeah. So, I would say emotion plays a really big role in all of these different relationships. You know, if we take a step back, kind of generally speaking, we know that emotion and psychosocial processes play a huge role in chronic pain. So, we’re thinking about things like depression, fear, anxiety, just to name a few. These are all often very closely linked to the experience of chronic pain. Now, in the emotion literature, there’s a theoretical model that’s been proposed to explain over general memory, not in the context of pain, but more so I think it was originally introduced to explain it in depression somewhere around the early 2000s. According to this model, there are three processes that block the retrieval of specific memories. So those are rumination on over general memories or general themes. Then there’s avoidance of sort of unpleasant emotions that can be triggered by recalling a specific event. And then finally, issues with executive control, like difficulty inhibiting or filtering out irrelevant information. And so, these three processes, either alone or in combination with each other, have been proposed to cause memory retrieval to become kind of stuck at the over general memory level. And so, when we’re thinking about chronic pain, it’s possible that there are similar mechanisms that might be at play when it comes to recalling painful memories. And kind of in terms of emotionality in particular, you know, there is some research that kind of points in this direction. So, for example, there are studies that show that people with chronic pain tend to recall more pain-related content in their memories. In some cases, they recall memories with more negative emotion attached to them. We also found in my master’s thesis work that folks who had more surgery-related content after undergoing surgery were more likely to have chronic pain up to one year later. So, you know, generally there are some findings indicating that individuals with pain have differences in the emotional aspect and sort of focus of their memories. And this is something that I’m also starting to dive a little deeper into with my own research as well.

Yeah, all important topics as we know pain is both a physical or sensory experience as well as an emotional experience. It’s always important to bring the topic of emotions back into the conversation. I want to back up just a little bit because You know, most people who listen to this podcast are clinicians, although we welcome people with chronic pain into our community to have these conversations. And somewhere in the beginning, you know, you and I were talking about the idea that there may be a memory bias in pain or people may be poor historians, meaning they don’t necessarily remember, or they can’t accurately describe what the experience is that they went through. That’s probably surprising to a lot of people with pain because I think most people would say, no, I remember this exactly. I remember how it felt. I remember, you know, what was going on. But the research actually tells us really a different story. And I’m just wondering if you can explain to us maybe from an evolutionary perspective or from a perspective of how our brain kind of privileges safety or not being traumatized, so to speak, which we look at pain as a trauma sometimes, why the brain may do that, why it may cause us to not remember these episodes quite as clearly as we think we do.

Yeah, and before I sort of dive into that question, I think you brought up a really important point, which is this idea of you know, using this language of memory bias or accuracy, when we’re describing memory for pain, there’s actually been a lot of discussions around that kind of happening more recently in the field of, you know, is it really a bias? Is it really inaccurate? There is an element of truth to that. But at the same time, when we think about memory, memory is a reconstruction, right? When we recall episodic memories, we’re not just replaying factual pieces of information of the unfolding of an event. So, I think, I think you bring up a really important point, which it is, it is important to be careful in the way that we talk about these things and maybe start rethinking, you know, applying terms like bias and accuracy when we’re talking about memory for pain. But kind of coming back to your question of what might be the sort of evolutionary, you know, advantage of thinking of or recalling memories in this way. So, one train of thought that I have is this might also bring up a distinction between the way ways that are more protective when we’re thinking about memories for pain in the more acute stage versus once the pain becomes chronic. So, you know, it might actually be beneficial or protective to think about pain in an over-general, less specific way early on, right? Like when you’ve just experienced the pain, it might actually be kind of traumatic or at the very least triggering. individuals to be recalling very vivid perceptual details of a pain. And so having like this over general way of thinking about things might actually serve to blunt some of that emotional and sensory intensity associated with recalling. However, I think that it’s once the pain starts becoming chronic, and you are continuing to recall those memories in that way, that might now be turning into sort of like an avoidance mechanism where the individual, you know, might be avoiding processing and integrating that part of their life into the rest of their autobiographical narrative. And that’s something that, you know, not so I think another point of caution here is like, when we talk about pain memories, they are not all necessarily traumatic, but we can draw an analogy to traumatic memories where there’s a lack of meaning making and integration into our autobiographical narratives. And so that is something that maybe might apply to chronic pain as well.

Excellent. I think those are really great points for us to bring up here as we kind of move forward. You’ve also worked with children and adolescents and looking at their relationship of kind of early life experiences and caregiver interactions. So much of our early life can inform how we relate to pain as we become an adult. What is that starting to tell us as clinicians when we’re starting to talk to people maybe about their prior life experiences as kids, or if we’re working with children directly who don’t have pain or maybe developing pain, how can we start to use some of this in a more adaptive way?

Yeah, so a lot of this is work that I’m currently doing for my dissertation, so to be determined. But in terms of the things that we do know, there is a bit of a literature on parent-child reminiscence and parent-child reminiscence in pain. So there’s some wonderful work that’s been done by Dr. Melanie Knoll and Maria Pavlova at the University of Calgary, which basically shows that parents that talk about their children’s painful experiences in a way that is, again, coming back to this idea of avoidance, not avoidance, but, you know, more elaborative and sort of focusing on some of the more emotional sides of the child’s memories, those children have better outcomes, specifically in the context of surgery. So, Yeah, I think that theme of avoidance is really important here. So, parents that are not afraid to talk about these topics with their parents in a way, with their children, sorry, in a way that helps them process it is really important.

So, let’s say maybe we can, because I know you’re starting to take your research, you mentioned your thesis, I’m starting to form it and say, OK, here’s how we can start to apply it to clinical practice. You know, I think low back pain, chronic low back pain is always kind of an easy case to start to look at. How might we start to take this idea of autobiographical memory, memory schemas and how they shape our beliefs and who we are, how we see ourselves? maybe even memory bias. How would we start to use that to maybe inform our treatment of someone with chronic low back pain, for example?

Yeah, so there’s a few potential avenues you can take with this. The main thing, the main kind of idea here I think is informing development of new non-pharmacological treatments for chronic pain. So, one example is something called memory specificity training, where people are essentially taught or trained to retrieve autobiographical memories that are more specific and more episodic, have more of like that perceptual richness to it. And this is an intervention that has actually been studied in various other populations where over general memory has been identified, such as depression. And in those populations, it’s shown pretty good effectiveness and increasing specificity and more moderate effects for reducing symptoms of depression. But that’s something that our team is now investigating in individuals undergoing major surgery. be applied to individuals with lower back pain as well. So, and even taking it a step further where you’re not just focusing on memory specificity alone, but also enhancing the episodic quality of those memories. So, you know, like the emotional content of the memory, focusing on that and sort of helping people process that. If that’s shown to be effective, then that’d be really great because it could be implemented as an adjunct to other psychotherapies for pain. So, in some sense, you can kind of kill two birds with one stone by simultaneously targeting kind of comorbid mental health issues that we know might be prevalent in chronic pain, such as symptoms of depression. You can also start to incorporate these sorts of treatments to actually improve other psychotherapies used for the treatment of chronic pain that rely on memory. So, for example, implementing it into cognitive behavioral therapy for pain, where clients are required to sort of draw on specific memories as evidence to, you know, support or challenge their beliefs. And so, using this to improve their memories during the session, and also for the session itself. And then kind of coming back to the idea of schemas, you know, there, there should be research, there could be research that’s that looks into the development of interventions that target memory schema. So, if schemas are an important piece of this puzzle, then that’s something that we can start to target as well. So, modifying more, so to speak, maladaptive pain related schemas, and trying to increase people’s more adaptive schemas and this is something that’s been proposed in social anxiety and you can start to incorporate that into chronic pain as well if memory schemas are found to be an important piece of this puzzle. The other thing I’d say is that beyond psychotherapy or psychotherapeutic interventions, you know, linking changes in autobiographical memory to specific brain structures like the hippocampus could open the door to potentially identifying neuroimaging biomarkers for pain. And that could be, you know, a big step toward providing better diagnostic tools and more personalized treatments for chronic pain. And especially considering that right now pain is mostly assessed through self-report measures like rating scales, you know, these tools, they do tell us about the presence of pain, but as we know, they don’t always capture the full picture, especially in patients who can’t, you know, easily express their pain, like infants or individuals with cognitive impairment. So that’s why it’s so important to be able to develop kind of more indirect methods of measuring pain as well, and to look at it from a broader sort of multidimensional perspective.

All really interesting topics. And I think a lot of that probably falls under the umbrella of memory reconsolidation and helping people access memories about pain and seeing how we can modify or change them. As you mentioned, schemas are a big part of that. There’s so much when it comes to pain and memory reconsolidation. I’m wondering what you think about is movement fitting into this aspect of pain memory and how we can access that and or change that.

Yeah, that’s a really interesting question. So, I think there’s, there’s several ways we can think about this or approach this question. But maybe one thing is if we’re thinking about memory schemas, again, you know, that could be part of the process of creating more adaptive schema. So, if an individual is afraid of movement, because historically, it’s caused them pain, maybe a path forward in terms of treatment would be encouraging this person to move more. And then through experience and reinforcement of kind of the positive outcomes associated with that experience, that can start to lay the foundation for more adaptive schemas. And sort of, instead of perpetuating like this vicious cycle of pain disability, do the opposite, right? person now starts to be able to function in their day-to-day life more closely to the way that they used to be able to. So, sort of creating these more adaptive schemas through experience and physical movement might be a good path forward as well.

Excellent. And I want to thank you so much for joining us this week on the Pain Science Education Podcast. and talking to us about memory and pain. I’m very interested to see how your work rolls out as you finish up your PhD and move throughout your career. In the meantime, please let us know how we can learn more about your current research and stay connected to you as you move throughout your career.

Yeah, absolutely. So, you can read about some of this research in my recent publications. So, I think I’ve provided the links to you. And I don’t know if I’ll be posted somewhere. Yeah. And then I’m also on Twitter. So, people can feel free to follow me. And I’m also happy to share my email if anybody wants to get in touch as well.

Excellent. So, of course, we will link to Anna’s email and the three publications that she has currently on pain and memory. If you’re interested in those, you can, of course, find those over on the show notes at the Integrative Pain Science Institute under this particular podcast, or you can email me, of course, [email protected]. And I’m happy to connect you with Anna and all the wonderful resources she has. Thank you for joining us this week on the Pain Science Education podcast. Please make sure to share this episode with your friends and colleagues or anyone interested in pain and memory. I’m Dr. Joe Tatta and we’ll see you next week. Thank you for listening to the Pain Science Education Podcast. To subscribe to the podcast and learn more, visit IntegrativePainScienceInstitute.com. That’s IntegrativePainScienceInstitute.com. Sign up to receive weekly updates and learn about our continuing education courses. If you enjoyed this episode, leave us a review on your favorite podcast platform and share this episode with your friends. Please join us next week as we share more science-packed solutions for treating and reversing chronic and persistent pain.

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Important Links

Website: https://scholar.google.com/citations?user=o5PMYr8AAAAJ&hl=en

 LinkedIn: http://linkedin.com/in/anna-waisman-164468b2

Handle: @Anna_Waisman

Link to Papers: https://doi.org/10.1016/j.neubiorev.2024.105736;   https://doi.org/10.1080/24740527.2022.2058474;   https://doi.org/10.1097/j.pain.000000000000264

Anna Waisman is a doctoral student in the Clinical Psychology and Neuropsychology program at York University in Canada. Prior to her graduate studies, she was involved with research at the University of Toronto where she studied autobiographical and spatial memory in individuals with healthy aging and memory impairment. Currently, her doctoral research focuses on investigating autobiographical memory in chronic pain, along with its neural basis in the brain. She is funded by a Vanier Canada Graduate Scholarship from the Canadian Institutes of Health Research, which supports a research project investigating a memory-based intervention for the prevention and management of chronic pain. In addition to being a PhD student, Anna is also the Editorial Manager of the Canadian Journal of Pain.