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20. Somatosensory Processing - Tactile, Proprioception and so much more.

This episode is all about somatosensory processing. Our Transcript gets a little wonky right at the end - we had some tech issues! But for those of you who enjoy the transcript, here it is!



[00:00:00] Michelle:Hello my friends. I can't wait to, uh, have another deep dive with you today, we are talking about some matter sensory uh, processing.We are going to try not to move too fast into Praxis

[00:00:15] So how we are gonna do that because Yeah, Cory, don't ask a praxis question to at least 40 minutes.

[00:00:23] Okay. So we're gonna try not, um, to go to Praxis too fast. Obviously, there's huge, inputs from a somatosensory sensory processing, influencers and contributes to Praxis. so that's a natural route I guess to go there, but we are gonna try and hang out in really just defining what is it and why does it matter and how does it contribute to function, for the kids we work with and we will

[00:00:53] possibly talk about how it might influence, other, sensory, systems like sib. But anyway, we'll get to Praxis, but we are gonna try not to dive there too. fast first. So Cory, how do you put it together? What is the, what is the somato sensory system to you?

[00:01:11] Cory: Well, I guess for the three of us, it automatically brings up tactile input and proprioceptive input. Um, I guess over time at some point those, like, you would hear the term enough and you would say, well, what do you mean?

[00:01:25] What's, what is that? Uh, and, and people would be like, oh, it's tactile and prop. Oh, it's tactile and prop. And then I, I was like, okay. So I guess those two together become somtosensory processing. I ended up looking up the word like the Latin root of Somato,

[00:01:42] And it means body, so makes sense like body processing.

[00:01:46] So what other senses that contribute to, um, me processing my body and it's like, not just these two sensors, but pretty significantly the tactile system and the proprioceptive system are going to give me information about my body. So that helped me conceptualize that and make that kind of link together a little bit more.

[00:02:06] Um, but I, when you were talking in the intro, Michelle, I had this thought about

[00:02:10] oh, if you say praxis Cory

[00:02:14] Cory: no, I promise. It's not a praxis related thing. It's a, um, modulation and discrimination question around somato sensory input. I'm just trying to think the, I guess with, with all the other systems, we have a pretty, I feel like it's a lot clearer where you get a modulation issue and, and, and in the tactile system, I see that I can really discern that there's a either a over, um, I don't know, I don't wanna say over response, but it's a big response to a small tactile or a, to a small input sometimes. Um, and I can discern that that child's nervous system is finding it. that input is overwhelming to them. But yeah, the, I guess in the tactile system, I can really clearly see that there might be modulation challenges, but in the proprioceptive system or I don't really understand how. How I discern modulation functions in the proprioceptive system and I just, I've never really associated proprioception with modulation to me, it's not in part of that primitive evaluative processing, but maybe it is.

[00:03:21] Maybe I'm wrong. Maybe let's clarify.

[00:03:24] Tracy: Yeah. So, uh, let's clarify. Um,

[00:03:30] Michelle: come on in. Tracy the clarifier.

[00:03:36] Tracy: I get to be the clarifier. Oh, that's So first of all, I love that you looked up that somato means but also interestingly proprio, it means oneself. or from oneself. And so in some ways, like before we jump into talking about modulation and descri, which we're gonna get to quickly, um, but there's this funny thing that happens when we talk about somatosensory processing and that is that it, it is, um, taking information from the body itself, and giving information to the nervous system about the self systems. And so in some ways, the proprioceptors, we think about them as the muscle joint receptors and fascial receptors perhaps. Um, but there's a broader category, so then we could think about it as the interoceptors, right? Sometimes we use the word interoception to think just about the deeper receptors that are in the gut or the viscera. The lungs, the heart, the respiration, the suck, swallow, breathe function. But those are all actually somato sensory receptors. So when we're talking about interoception, when we're talking about muscle receptors that are sensory receptors, when we're talking about skin receptors, endoderm, ectoderm, those receptors are all tactile receptors and those are all parts of the somato sensory system.

And so, you know, you can kind of carve the world up in different categories interoceptors versus exteroceptors, receptors of the self. But what's interesting is that our ear muscles, are muscles, and there's somatosensory receptors that guide our listening, our eye muscles, that are taking in external information from the visual surround.

The information is, is gathered by the proprioceptors of the eyes. And so even our vision is actually mediated by somato sensation. Listening, swallowing all of those functions. Yeah. Yeah. They're all based in somto sensation. So in some ways, the vestibular system is this grand system

[00:06:24] we talked about it in the last episode but the somato sensory system is mind-blowingly connected to everything. So I just think that's important to kind of say, Yeah. And

[00:06:39] And I, I guess, You go.

Cory: I oh, no, I was just gonna say, if, if I was being particular in the word somato, meaning body, all of those things relate to body, so that makes sense to me now that, you know, interoception could also be part of somato sensory processing.

[00:06:56] Michelle: So it's just historically that we pulled that out or Ayres pulled that out, or is that where the thinking was at the time to have it separated and it not necessarily sitting under interception? Like why? I've never thought about that, Tracy, but you're right. I've, I know that there's some discussion around, um, the vestibular labyrinth being a proprioceptor, but, um, you know, I, I think we shy away from that. Like, I think in the latest SI book they go, ah, for the, you know, purposes of this book, we won't, you know, be going there.

[00:07:33] Cory: Do you think it's to do with the fact that, sorry, Michelle. I was gonna say, do you think it's to do with the fact that it hasn't been really, like the interoceptive processing part of Somato sensation has been like kind of not recognized in a way earlier on, so maybe that was pulled out to kind of just make it a thing, like do you think maybe it just flew under the radar and then people are like, Hey, wait a second, like this is a really a thing and we probably should be paying more attention to it. Like, is that why, why we pulled that out so that, that it's.

[00:08:05] and it's a re categorization rather than a, now we know, we talkin' about, you know, "bud" introduced the concepts of, um, to us. Yeah.

[00:08:15] Yeah, totally. That's exactly what it is. So it isn't a concept that was talked about when Dr. Ayres was writing and even though sherington and people way back in the 18 hundreds and even before that would talk about it, now there are people who claim that, you know, it was sort of discovered in like the 1990s or which I'm sort of poking fun at.

[00:08:39] Okay. I'm sorry, I should regard all scientists as, um, fully regarded and I do, but I just think that there's history that you can carve up the world in lots of different ways, and maybe this is like the least important thing that we should be talking about, but it, it's confusing to people because they think, oh, interception, that's so earth shattering.

[00:09:03] And, well, it's all under the same theory that Dr. Ayres wrote about and so it's just different concepts and words applied to different parts of the body and different ways the receptors might work. Um, what's interesting in the interoceptive work that's going on now is there's a lot of focus on, on this phrase, interoceptive awareness, which is sort related to how, when we're aware of, you know, the feeling that is arising in our body, that that awareness can lead us to a different.

[00:09:40] set of solutions that might, um, be available to us for coping or regulatory functions or for taking care of our physiology. Like, I'm hungry, I'm thirsty, I'm needing something. But, awareness is a skillset that is really related to precision of processing. So it's kind of this blending of sensory discrimination and sensory modulation.

[00:10:08] So let's talk a little bit more about somato sensation and how there really are structural and functional, neural pathways that support modulation and discrimination and they give rise to different functional capacities and that's what we have to be able to tune into as clinicians is the thing that is troubling for this, individual that we're supporting.

[00:10:34] Is it really based in processing difficulties in one or the other system or how they interact with each other? And we always have to be disciplining ourselves to do that kind of clinical reasoning. So yeah, so sensory discrimination, gives rise to perception action processing, and it gives us the capacity to be come quite skillful and to use the awareness of our body to guide our ability to be able to, do everything from

[00:11:09] throw a hammer against a wall because we're trying to play a game that's hammer throwing or to be able to, yeah, that's like a game, right? Or is it? I don't know it

[00:11:21] Ax throwing.

[00:11:21] Oh, ax throwing. That's it

[00:11:23] Yeah. Yeah, yeah, yeah. Well, you certainly know the people. You wouldn't go ax throwing with

[00:11:30] You Americans, I dunno up to over there.

[00:11:33] dunno we have ax throwing. I've never been, but I've seen videos of axes bouncing back off walls, that makes me a little, little concerned. Um, but yeah, fun, fun, fun.

[00:11:46] But it allows you to do the things that are like vigorous intense, power driven and it all the way down to, think about, uh, a neurosurgeon having to finesse the most, exquisitely intricate kind of, manipulation of their fingers in, in order to create something that most of us wouldn't have the skill to do.

[00:12:10] And so you or an artist or a musician, who can use fine nuanced action patterns to produce these exquisite results, right? So, the system can be so finely tuned that it allows you this super high degree level of skill in athletics or in, aesthetically driven kinds of skill-based actions. But also just like in our everyday life, like when you have to zip your coat and you can do it without looking, when you need to open your water bottle while you're, you know, opening the car door or something, and you can finesse multiple motor plans all at one time and be aware of where your elbow is pushing the door and how your hand is turning the jar,

[00:12:59] and all of those things are available to us simultaneously because of the exquisite processing of the body receptors, the somato receptors.

[00:13:10] So, where do we hit? Uh, can you help me with the modulation component of, um, somato Sensation? I guess that's tricky because there is a number of different receptors involved,

[00:13:23] like it's not just one pathway from the vestibular labyrinth into the, like, there's tactile, there's propreceptive, now I'm learning, there's all the other components around interception and the processing of one's self in any way. So I guess, is that why it's hard to pull apart the modulation piece around this?

[00:13:41] Or like, how should I be thinking about it?

[00:13:44] Okay, so the somato sensory receptors that are either tactile or proprioceptors, whether they're coming from the limbs or the core of the body or from interoceptors the information is gonna ascend through the detail system that goes through a particular set of pathways called the dorsal column, medial lemniscus system.

[00:14:11] There's a tiny bit of, detail that's also carried by the partner system, the Anterolateral pathways, but most of the anterolateral pathways carry information. , into more low level brainstem and really low level limbic processing, and are involved in, uh, detecting whether information is comfortable or not comfortable.

[00:14:41] So it's the valence based processing, is informed by modulation, and that's true of tactile and proprioceptors and interceptors.

[00:14:52] Oh, I had a thought. Is it at the point where, you know how, if you get your, I'm thinking of jujitsu, but you know when you get your joints stretched to the point where you're like, it, I might hurt myself here, is, that then the modulation function of the proprioceptive system coming in, cause that's uncomfortable, obviously, and you're getting a firing.

[00:15:13] Okay. I'm, I'm with you now.

[00:15:16] Yeah. So it's always on the valence of comfort to discomfort, pain versus safety. So it sets up that valence and it detects when there are shifts that are moving you out of comfort and into discomfort. So the proprioceptors are a really, really critical part of our pain, registration and circuitry.

[00:15:38] But what's interesting is I've worked with a number of kids. Once I understood this, you know, I could see where like little ones I would be working with who were, um, had, had differences in the way that they weight shifted. They were often really uncomfortable with weight shifting because the proprioceptors of, wait, you want me to have a weight shift and,

[00:16:03] and some of that's gonna pull me off of my midline. So the relationship of vestibular proprioceptive processing can set up where the proprioceptors start to be restricted in what's comfortable. And you can see a lot of kids actually, once you see it, then you're like, oh, I see what's happening there.

[00:16:24] Where there's this defensive over negative response, which is a modulation difficulty. Um, and it's related to poor processing in general, but related in that case to proprioceptive over response or defensive response.

[00:16:42]

[00:16:42] Michelle: Could be related to vest processing as well in that avoidance. I don't wanna move off this space, so I'll stay here, but I'm starting to feel some pain cuzI've been in this position for a long time. Oh, I've gotta move off that. So could that be, you know, that's another profile I guess where it's the, the vestibular system saying stay put, stay put.

[00:17:14] But the props. going, oh, I wanna move, I wanna wait shift. I, I'm feeling this deep pressure andI wanna shift it to the other side now.

[00:17:22] Were you sort of saying though, in your example, Tracy, where with Michelle's example, the kiddo is, um, getting, say they're kneeling on one knee and that knee's starting to register. Hey, detecting some pain from kneeling for so long "weight shift". So that's one situation where the body wants to shift the weight.

[00:17:43] But with your example, Tracy, were you talking about kids that don't want to shift the weight due to a midline processing, body in space issue, and then because of that, I guess this is where the vestib and the prop integrate together. But because of that, uh, unsurety around managing their body in space, you get that signal from, primarily from the vestibular system, but it's then translating into pain with the weight shifting on, or not pain, but discomfort or, resistance to weight shifting in the proprioceptive system because there's the vestibular based challenge around midline and control, and then it's perceived as a threat.

[00:18:22] I guess the weight shift is perceived as threatening to my stability and my sense of myself in space. And so now I'm going, ow, ow. Or I look funny, like, I don't know. Is that what you

[00:18:33] what were, yeah. Maybe.

[00:18:35] Oh, you do it? It becomes phasic. Yeah. Cuz it's like, Ooh, I'll just right over to the other side really fast. Yeah. So that brings up the whole, so yes, in the proprioceptive system, you can see modulation based problems with movement patterns, but it's based more in. Phasic movement, fuels the higher level proprioceptive pathways more likely. The tonic holding patterns fire more into the antero lateral pathway.

[00:19:05] And so you do see this sort of resistance to maintaining tonic holding patterns in the proprioceptors

[00:19:12] So you have, say you have a kid. I was before, I was thinking how, it's surprising how the vestibular, input disrupts the proprioceptive modulation function because you get a perception of unsurety in the vestibular processing or a weakened vestibular processing

[00:19:28] and that's influencing now weight shifting, which is a proprioceptive, tactile, somatosensory function. But then if, so, if I rapidly fire, and I guess this makes sense, but, so if I rapidly fire or rapidly move my body in space, I fire more into the dorsal column, medial lemniscus pathway. Is that right?

[00:19:45] Which is more discriminative. So what I'm getting myself, I'm giving myself more body awareness that makes sense. That makes sense. I'm, I'm, I'm activating it more rapidly. But I, but if I, so if I'm tonically holding my body in a position, I'm not getting as much discriminative input.

[00:20:05] Is that right?

[00:20:06] Yeah. Well if you really tonically hold and you don't have phasic, a little adjustments that are happening. The tonic, can either habituate quickly so you kind of lose the, the source of information about where you are. And also the tonic proprioceptors, help to activate the inhibitory GABA based functions thatare holding really down regulation and deep inhibition.

[00:20:35] And so they set up habituation cycles and they are involved in a lot of the modulatory functions. so there are all these different kinds of gating mechanisms and gating can happen in lots of different ways. So if you, if you stub your toe, you

[00:20:52] you shake your foot to activate phasic kind of gating, but you could also just hold pressure and it might down-regulate it rather rapidly, right?

[00:21:04] So we have different ways of shifting the intensity of response, and that's related more to the modulation functions. And your nervous system organizes those based on shifts in relative states of comfort or discomfort. So if you're in an upright posture and you are activating tonic, activation to hold yourself, and then you get engaged and paying attention to something, you're not gonna maintain that active activation.

[00:21:38] So you're gonna kind of slide out of it. And then, and then what'll happen is you'll start to feel what Michelle was describing, a little discomfort like, I need to wait shift here because I'm kind of sagging on my bones. I'm kind of sagging in my joints. And so then that little bit of discomfort is a signal that says, no, I need to activate again.

[00:21:59] Because the tonic receptors don't stay active without activation and they tend to mobilize, uh, inhibition anyway. So it's hard to maintain it versus the phasic receptors, which are gonna be quickfire. So you can't maintain quickfire. You, you, you have to stop. You quick quickfire and then you need to recover and you quick fire and you recover and you quick fire and you recover.

[00:22:27] But the detail that I quickfire because I reach out in space and then I touch the object that I need and then I need to do something with that object. I need to use it. I need to pick it up or I need to hand it off, or I need to do whatever I'm gonna do. That's the perception action cycle. And then it sets up the action pattern that changes this, the firing.

[00:22:52] It changes the feedback, it changes the sensory signal so that you can have another phasic action in response to the next thing. So people who are very skillful at motor action, for instance, they're continually responding to the update of the phasic firing pattern. And so the propri ceps in the dorsal column keep giving a little bit of different information, and that keeps generating a fine tuning of the motor response.

[00:23:22] And so there, there are two different pathways, two different systems, two different sets of functions that we're always needing to talk about because it's complicated and it's trying to translate it into what we see in kids. You know, is that modulation, is that descri? Is that modulation? Is That's why we have to have good tests and we have to have really strong clinical reasoning to, to sort it because it, it is a little bit nuanced for mm I swear it would be a blending of tonic and phasic inthe ideal situation, is that right?

[00:24:00] Because maybe I need to tonically hold my core and I need to phasically move my arm.

[00:24:05] So I guess it's, yeah, it always gets complicated, doesn't it? So I find it easy just in, you know, that comment you made about discerning and, you know, and being really, specific in our observation and testing. For me, that's why I don't bundle them together a lot, and I do in my thinking, and probably when I'm mentoring staff, you know, pull it out. And so tactile is separated from proprioceptive.

[00:24:31] For me, when I put it together, it gets a bit a emeshed. But in those examples, you provided Tracy, um, you do well to pull tactile out, to pull, prop out, as we would, with Vestib and vision, knowing that they work that

[00:24:48] together in the way that you just mentioned, Cory, that there, you know, in my mind I was thinking about that holding a posture.

[00:24:55] Um, the muscles, spindles are being really activated. to hold me up or pull me back up as I really getting engrossed in what Tracy's saying, I'm collapsing down.

[00:25:07] and then

[00:25:07] either the muscles are stretched, my skin feels stretched as well, so I'm getting that tactile input, but then I'm getting to an end range in my joints.

[00:25:17] So the, the proprioceptors are saying, Ugh, bone or bone end range, you know, perk back up again. Activate muscles and sit back up. So if I've got that right, they work together. But in the clinic I actually wanna watch the child in terms of tactile and in terms of prop, and I guess that's what our assessments and clin obs are doing that we are trying to pull out.

[00:25:41] When Cory and I did the SOSI with Erna Blanche, she was pulling out what. Some of the traditional things that we've looked at in the clin obs because they merge tactile, prop, praxis, there's too much in that action to actually just say that it's a test of tactile function or prop function.

[00:26:04] I think like you cor in maybe in that, your influence in the clinic. I came back from an in block of intensives and everyone was saying somatosensory sensory processing. It was like, whoa, whoa, . Who's been here? Tracy has cory has Cory's introduced term.

[00:26:19] But yeah, I know it works together, but it just helps me be really specific. If I don't always, in that initial stages, consider it as a unit.

[00:26:30] Well, what do you, what do you look at then, Michelle, if you're thinking specifically about tact, like, cuz you were saying in the clinic you wanna look at the tactile processing and you wanna look at the proprioceptive processing. And so are there distinct things that you, that you kind of watch out for that might signal, maybe a tactile processing component in this thing is being disrupted or not precise or something is going on with the tactile system here, or vice versa with porp, like you have specific things that you've seen that can trigger people a idea of that.

[00:27:05] I can't really think about it off the top of my head, Cory. Um, I didn't specifically have an example for tactile other than like a, um, a sort of unrefined movement in terms of interacting with objects, makes me wonder about tactile system.

[00:27:19] But eh, like could, it could prop could be about prop as well in a way, but for me, prop, I always wonder about propreceptive processing in, um, grading of force and how much pressure they're using and like that to me seems to me more significantly proprioceptively involved rather than, Tactily driven.

[00:27:40] And I know that they're still, they're both always going to play a role like you said Tracy earlier, we weren't recording, but because of the homunculus, I guess, they both feed into that.

[00:27:53] and tactile kind of is easy in that like if their clothes are bothering them, then Well, that's the modulation part. And then scrim part is, can discern in that little bunch of

[00:28:05] something.

[00:28:06] can they discern in the beads? Can they pick out the thing that's not the bead, So tactile, I guess, in the, sequential finger touching is I look at that.

[00:28:16] I know you can get, prop and tactile, but I really look at the force, that they're using to bump their index finger to their thumb. I do look at the location as well. I know that's a bit informed by tactile. So that speaks to me as prop more than a tactile. So I just try to pull some of those out and then blend it together. But it just actually doesn't help me because , because the kids, as we know, well, I'm not gonna go praxis first, Michelle, don't go praxis first, but it starts to get a bit, you know, even when say, you know, um, can you do this?

[00:28:57] If you're getting into supine or prone positions. some of the stuff that we are doing in the clin obs has got such a praxis and following, um, verbal command, element to it. So, yeah,

[00:29:10] So Michelle, it's so interesting to think about the, where's the division or the line between tactile and prop

[00:29:18] Mm-hmm.

[00:29:19] and sometimes it is hard to separate, partly because once they start getting processed, they're really partners, but let's think about this kind of quintessential activity, like playing in the beans and you're trying to find something, right?

[00:29:37] and what you're noticing is that as the child is exploring, so exploration, promotes, the discriminative system to be engaged To tune in, to pay attention, to be motivated to find the thing or to make the discernment between where's the little spider thing or the little rabbit that I'm looking for versus this other field that I'm feeling.

[00:30:04] Right. So it's a, a figure ground tactile discrimination, comparison. And what happens is that the propprioceptors, our grading. So Cory, you were talking about that sometimes the marker is more about the grading and timing is a little bit more propreceptive in nature. And the fine tuned response of, let me use my distal part of my finger to be precise, to create a really fine pincer grasp, to find that thing,

[00:30:38] is more tactile in nature. When we have kids who have difficulties with tactile, what happens is that they're whole hand out operates almost like it has a mitten on it all the time. It doesn't have that fine quality of being able to make those little discernments, and so you see more ungraded motion, but you also see an inability to get the quality from the tactile system that might help the proprioceptors to refine.

[00:31:07] So they work as a tandem Does. , kind of clarify that a little bit. And then I also always think about, watching not just grading force, but also as you reach out in space, can you maintain the trajectory of the limb? Can you maintain the, directionality, can you maintain the bilaterality in that or not?

[00:31:31] Those are more proprioceptive in nature. But once you get to the object that you're gonna pick up, let's say you're picking up, a pencil or a cup, and you, when you get to the, the distal point, you get to the pencil, does the hand configure? In a way that is shaped to be able to be automatic and quickly pick it up.

[00:31:57] So that's more of a combination of the tactile system and the proprioceptors guiding that. But then when you go to pick it up, it's the tactile system helping you to guide the finger action. So it's always the combination, but as you're observing, and it's hard to say all this in words, so this is one of those things where sometimes podcasts could be a vlog, right?

[00:32:25] Where video show this cuz it's

[00:32:29] show it Tracy,

[00:32:30] so many words, right? But yeah. So if I'm if I'm picking this up right, my hand should be in the shape of the vessel, way back here in the reach and that's prop. But then once I get there, the fine tuning of how hard, So there's prop that guides the heaviness, but my fingers touching it and conforming to the shape that's more tactile.

[00:32:58] So it sort of depends on what the function is within the function and, yeah. Interesting.

[00:33:05] in my development though, when I interacted with objects such as your water bottle and I tactally received the information about that object, has that informed now my ability to preemptively use my proprioceptive system to shape my fingers into the shape of knowing that, the water bottle is round.

[00:33:27] And now I have that information. in my capacity to then use, I've, I know what this object is, like I know what it feels like in its sensory elements. And so now I've used that information and it's in embodied in me. And now I can use that to guide my propioceptive system, to anticipate the fact that I need to shape my hand in a rounded shape to pick up the water bottle that I'm picking up.

[00:33:53] So is that,

[00:33:55] is that how we develop this?

[00:33:57] Yeah, it is, it is how we develop it. And so that's through this process of affordances, right? That's the word we use for that. And the affordances of what we have capacity for, what we understand and what's available out there in the world shape, how we build our schemas and our capacities. but then I'm thinking about, okay, so this is a metal water bottle that I'm I remember working with this kid years and years and years ago, and I had a metal water bottle, and he would never touch it because to him, metal didn't go with a drinkable container.

[00:34:39] So for him, in his mind and in his, the way he had kind of coded the world was that a drinkable container had to never be metal, and that metal was clearly not a safe thing that you would anything out of.

[00:34:53] And so, you know, it was a funny thing to kind of realize that the affordances sometimes are telling us about information and meaning on levels that interact with all of this. And gosh, that's sort of in a tangential story, but tells you about how affordances bring meaning and meaning comes from the sensory motor experience.

[00:35:20] Anyway. I'm thinking of a, water bottle that's a soft plastic that's got a bit more resistance or, uh, um, so it's not as slippery versus when I first touch a metal bottle, or particularly in.

[00:35:35] We're in cooler climates at the moment. So it's got the temperature input and it feels a bit more slippery. So I see it as props come on in to help shape the hand in a, in a position to grab the water bottle. Tactile said, Ooh, it's, oh, I'm gonna not put vision in tuck. Uh, tactile said, whoa.

[00:35:54] It's slippery, uh, than plastic. It said pro put, you know, pro put some more pressure on. Um, yeah, that's an, a tactile said. Yeah, I got it now. Thanks bro.

[00:36:06] got it now.

[00:36:07] and then helped you grab a bit of weight. Yeah. Yeah, we got it. We got it. That's a precise amount of weight. Okay, team. We got the drink bottle to the mouth, I guess this gets disrupted when you don't have good quality information. Or maybe it's not the receptor itself that's not getting the quality or somehow the quality's being lost in the integration of everything.

[00:36:28] I don't really understand all of that, but I know that the outcome is that it's hard to do the job of shaping my hand in, in fine nuanced ways or adapting to the feedback as I get it. And the only reason that it's so fascinating to me is like right at the moment, Audrey, my baby, she is just doing all of this stuff that'smissing and not getting her mouth and tipping things too far.

[00:36:51] And, and it's so fun to watch cuz like, it happens, but it, which it refines. Hopefully We'll find out. . No, she's so, she's going well. But yeah, like, you know, every time she's curious about the way that it hasn't happened the way she thought it might, you know, there's a, like, there is a tuning into, um, the fact that it's not quite the way she thought it might happen.

[00:37:16] And sometimes it's fun that it didn't happen that way and it's like, now it's a new thing. But, you know, there was clearly a sort of an intent and a plan. lets just say to bring the cup up to her mouth and to drink from the cup. And sometimes, the top of the cup is hitting her mouth and she's tipping the, the water down onto her shirt or like, it's just even coordinating all the actions and everything.

[00:37:38] But there's just this ongoing feedback between what happened, what did I get, how do I respond to that? Maybe will I do it differently this time?

[00:37:48] so it's just if there was an adequate integration or potential for integration for her, then I feel like it would not continue to refine over time, I guess. Yeah.

[00:38:00] I one more question about.

[00:38:38] yeah, I think some of the individual differences we haven't really even begun to study enough. Some of it is that the different receptors have different speeds of processing. And so you have, and then that ends up sort of creating this micro sequence in the way that it gets integrated, where just like you described Michelle, like pro, pro prop tell , tactile, tactile, tell prop, and there has to be this kind of relationship where, you know, the tactile of getting the vessel onto your lip.

[00:39:14] then triggers the prop, then the tactile, you know, they're interacting with each other in a sequential way. And the, the different receptors actually have different nanoseconds of firing patterns that have to stay organized in sequence. And we know that so often, one of the primary problems that can happen with processing, integrative processing is that there's sequences get out of whack.

[00:39:41] And so you see mis coordination and it happens all the time. And we just refine it. We just, oh wait, I need a little bit more tactile, or I need a little more prop to sort that out. And so it drives. Almost like micro moments of sensory seeking. Like, oh, I need a little more tactile to find where is the bottle on my lip?

[00:40:04] Oh, I need a little more. So it drives you to get more of what you need, or I need to squeeze it a little harder to have control of it in my hand. Um, so you have this continual feedback back and forth, back and forth. Get more information. Um, that smooths out the coordination. And we have little micro moments of mis coordination all the time that get refined.

[00:40:29] And then as we practice and rehearse and repeat, the chances of the mis coordination are diminished because the nervous system says, I know how to do that pattern. I know what it means to pick a vessel up from the table and bring it up to my mouth and get the liquid into my mouth. And so then I refine the pattern and then I don't keep making those little micro mismatches and the matches start to drive.

[00:40:57] The pattern and the sequence becomes refined and repeatable, and then you barely make mistakes anymore. And so the toddler learns how to drink and then they quit spilling because now they know, oh, I know what this is about and I've got the pattern down and I know how much force to put the cuff against my lips so I don't dribble.

[00:41:18] And, and they get that based on the sensory motor experience. Right. It's very cool how it refines.

[00:41:26] and it's cool how toys for babies are naturally graded. not all of them, but a lot of them are, right. They're either bigger, they have like bigger handles, or not even thinking about cups. I'm even thinking about puzzle pieces or the object that goes onto something else.

[00:41:41] Like if it's a lid or something, if it's a really classically graded baby toy, it'll be bigger and it'll be easier for them to hit the target so they can get the idea of how to do the action. And then I guess as they get it, it, it starts to sort of grade down and they could do it in a finer capacity.

[00:41:55] And it's kind of what we do as OTs in grading the task, right? Grading it to the appropriate capacity for success to get the action and whatever.

[00:42:04]

[00:42:04] Michelle: Prax

[00:42:25] first. Um,

[00:42:28] uh Yeah,

[00:42:29] let's talk about that.

[00:42:31] What

[00:42:32] Praxis categories, um, that, um, so perhaps let's start there.

[00:42:49] yeah, for sure.

[00:42:50] so the clusters, we think about like Ayres did this research to determine the relationships between the different kinds of basic, especially discriminative processing and how it gave rise to different functional capacity. So kind of in reverse by identifying the problem area, she identified the cluster.

[00:43:14] So, somato, dyspraxia is, A body-based coordination problem. And it's the kind of most classic dyspraxia. It's where you have a hard time knowing about where your body is in space, knowing how your limbs move in space, knowing how your, any, any body-based function, just how the coordination works.

[00:43:36] And what you end up seeing is a reduction in tactile discrimination. So, you know, localization of touch, or being able to identify moving touch. And what does that mean and how can I localize it? And can I tell if you touched me on the right side of my hand or the left side of my hand on the top of my thumb or the back of my thumb, can I tell if you touched me on my arm closer to my elbow or closer to my shoulder?

[00:44:07] And you know, most of us take body schema for granted because we're pretty refined at it and we're quite good at it. So when you meet a child who literally cannot tell if they're supposed to move their foot or their hand in order to climb, um, because their body map in their mind is so unrefined that really their hand in their foot are almost the same thing.

[00:44:32] Um, and those are the kinds of kids that end up responding beautifully to the interventions that we offer because we're helping them to have the tactile propreceptive vestibular. Social, playful, exploratory experiences that help them to fine tune and get the information that they need to make the homunculus make any sense.

[00:44:56] This is this body map in the somato sensory cortex in the thalamus, in the cerebellum. This map that tells us about the detail that allows us to create these really skillful actions. Um, and when you're, when that map isn't fine-tuned, trying to figure out how to kick a soccer ball or, cast a fishing reel or zip my zipper on my coat or, or pick up the vessel to drink a cup of water without spilling all of that is super hard.

[00:45:27] So Somato dyspraxia is one of the clusters that classically has, really revealed itself to be a true dis disruption. And, it's more than just a coordination disorder. It's a somato sensory based difficulty with coordination that leads to somato dyspraxia. it's a specific real entity, um, that we can identify and through the, EASI tests or the old SIPT tests, we can get really precise information to identify this quite, quite specifically

[00:46:03] and then we can target our treatment much more precisely and efficiently if we know how to test in order to derive our treatment planning. Mm-hmm.

[00:46:14] So the EASI and the SIPT, they would help you. Discern the clusters out. Um, for your treatment planning, I'm guessing. Those would be the pinnacle of tests. But there are published other resources and what you have to understand is what is it that you're looking for? You can test tactile discrimination from other tests. You can, link that to coordination function through other tests as well.

[00:46:39] And, and so like in the sensory integration theory and practice textbooks, there are some descriptions about how you might use other tests. Um, if you don't have those at your fingertips or you haven't been trained in them, we don't wanna limit practice by not having that training and we wanna encourage people to have the highest level of training.

[00:47:00] So it's kind of both. anyway, the other cluster, so that I'll just tick through quickly, one is, a really interesting cluster called a praxis on verbal command problem. So you see the same body-based awareness difficulties, but it really shows up when you use language to try to guide the child to use their body in space.

[00:47:22] So you say, put your right hand on top of your head and your left hand on your tummy, and they don't really have, it's not a language processing or cognitive issue, but they can't figure out. They start groping and it's like, wait, you want me to put my hand where? Which hand where? And maybe they put their hand on their face instead of on the top of their head.

[00:47:44] And so location of the action is confusing and it's hard for them to make sense of it and it's a really particular cluster. We also see a cluster that's related. Go ahead.

[00:47:59] ahead.

[00:48:01] Yeah. You're to

[00:48:27] show? Yeah. Hey. Yeah. And

[00:49:00] Yeah, absolutely. So they can do it readily on imitation, but if you say the words, it's like, what are you talking about? It's a really particular coordination.

[00:49:11] Problem. A really particular Praxis problem.

[00:49:14] And then, Ayres identified a couple of other clusters. One is, more of a vestibular based issue, but you do see proprioceptive difficulties in it, and that is a problem of bilateral motor coordination. Um, interestingly in bilateral motor coordination, you also see a lot of oral tactile.

[00:49:34] weakness and that midline of the body is organized by the vestibular system. So the, I, the speculation anyway is that anything that's more midline oriented is gonna be harder for vestibular, uh, or the, for the bilateral motor coordination or bilateral, um, integration and sequencing problem. You can hear it referred to as both bilateral integration and sequencing, or a bilateral motor coordination problem, but a sequencing problem associated with it.

[00:50:04] Yeah. The acronyms I've had I see are B i s. So the bilateral integration and sequencing, is that right? And then, or b i s and bmc, bilateral motor coordination. So it's, but they're the same. They're referring to the same thing.

[00:50:17] same thing. Yeah, yeah, yeah. And there it's, you know, a balance based, um, you'll see balance issues, really classic vestibular based processing issues. And then these bilateral coordination issues, often the right, left, you know, um, coordination is really strikingly difficult, but bilateral coordination could also be, you know, moving from the front of space to the back of space or from the top of space to the bottom of space.

[00:50:45] So bilateral is anywhere there's a midline and you see a breakdown in this smoothness and accuracy of the coordination in those planes of movement. Mm-hmm.

[00:51:00] Michelle - Audio than.

[00:51:49] You just said that.

[00:51:52] than

[00:51:55] Tactile, That's exactly right. So that's the way that you would discriminate this in the testing profile is that the vestibular loading of, um, and then the, the functional capacity for bilaterality and balance are the ho hallmarks of that. And certainly there are partners to the vestibular system, so they may be weak as well.

[00:52:37] But the hallmark issue would be vestibular versus somato dyspraxia, where the hallmark issue would be prop and tactile. And the vestibular system may be a bit weak, but you see this more. Loading of difficulties in, in the somatic sensory processing. And then you can have a generalized global dyspraxia and you would have all of those issues showing up simultaneously.

[00:53:02] But these are different clusters. You see groups of, children or adults who fall out in a really clean way into these different clusters. So they really do exist. They really are difficulties we can describe and identify, and then we can have precise treatment plans that map directly onto those profiles.

[00:53:23] And that's what's so powerful about knowing the profiles.

[00:53:28]

[00:53:33]


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