Articles Of The Week January 20, 2019

 

Coming out of college, everything seemed so straightforward! You’ve got a toolbox of techniques and you may even look to specialize in one of them, all the while helping as many patients as you can. Well, things aren’t so straightforward, and the times they are a changing. With it usually taking 17 years for new research to be applied in practice, we need to stay on top of the new and evolving research, along with a strong alliance with those patients.

“Manual Therapists: Have You Lost That Loving Feeling?” – Paul E. Mintken, Jason Rodeghero & Joshua A. Cleland

Patient centred care means different things to different people. Because it has different meanings for different people, there may also be ethical dilemmas surrounding the topic as well. This article delves into some of these topics, while also having you reflect on what this topic means to you.

“‘Patient-Centred’ – What Does It Mean And How Achievable Is It?” – Andreas Laupacis & Jennifer Gibson

Using unstable surfaces for strength training and rehab has been a popular practice for quite some time. However, does it really work? Well, it depends on the patients goals, your scope of practice, and just plain sticking to the basic principles of exercise program design.

“Is Unstable Surface Training A Waste Of Time?” – Nick Ng

He has been at the forefront of pain research over the past number of years and Peter O’Sullivan is always worth listening to. No different with this article, where it shows how he and his team are using ‘Cognitive Functional Therapy’ to treat back pain.

“The ‘Mythbusters’ Of Back Pain Believe They Can Treat It – With Words” – Liam Mannix

We published a post earlier this week about when NOT to treat a patients thoracic pain, but when you can, this is a good post. Dean goes through a few different drills and exercises to help increase thoracic rotation, most of which you can do right in your treatment room.

“Cleaning Up Thoracic Rotation” – Dean Somerset

Using “AIDET” To Successfully Communicate With Your Patients

 

In school, we are taught a list of history questions to ask patients.

But,  how often do we allow patients to ask us questions?  And should we?

The Journal of American Medical Association Neurology recently published an opinion commentary addressing fundamental questions every patient has but never asks.  While the article is geared towards physicians, it is applicable to all healthcare providers.  Keeping the patient’s concerns in mind can help solidify the relationships with our patients and improve adherence to the treatment plan.

Research repetitively shows that one of the largest predictors of successful care is the patient thinking the treatment or provider will help.

While it may seem daunting to keep these concerns in mind, many places use a simple framework called “AIDET.”  It is a simple acronym that represents an easy but powerful way to communicate with people that improves connection, expectation, and compliance.  

 
  • Acknowledge (use person-first language and call the patient by their preferred name. Key message “you are important”)
  • Introduce (who you are and what role you play in their care. Key message “you are in good hands” )
  • Duration (what can you expect today and in the future.  Key message “I anticipate your concerns”)
  • Explain (who, what, why, next steps. Key message “I want you to be informed and comfortable”)
  • Thanks (thank the patient for taking the time to see you. Key message “I appreciate the opportunity to care for you”)

How do you think you can implement the commentary or this framework in your practice?

 

Link to cited article: “Five Questions Every Patient Has but Never Asks”

 

 

Articles Of The Week January 13, 2019

Have you ever been wrong? I have been A LOT! The question is, can you be humble enough to admit it and in turn change? Can you have intellectual humility? Well, an argument is being made that science (and healthcare) need to cultivate more intellectual humility to advance. Part of this is having a balance between our convictions and humility because we need to listen to each other.

“Intellectual Humility: The Importance Of Knowing You Might Be Wrong” – Brian Resnick

Keep in mind this post is satire! However, it makes a great point about fads in our industry. I found it funny and I hope you and your patients do too.

“Ask Dr. Dumb: All About Foam Rolling” – Mark Remy

Written by a doctor this article gives some sound advice about most things ‘fad’ in the health and wellness industry. Much of it could certainly be applied to many of the manual therapy groups boasting huge benefits to their new technique (which I have fallen for and taken courses on in the past). Wellness for us and our patients are meant to be a good thing, not a complicated explanation full of pseudoscience.

“Don’t Fall Prey To The Cult Of Wellness” – Margaret McCartney

Early in my career (and I know I’m not alone) I would always use the pain scale of 0-10, with 0 being nothing and 10 being ‘the worst pain you’ve ever felt’. In the hospital setting, doctors and nurses are saying this system doesn’t work and are trying something new. They’re using words instead and asking is the pain ‘tolerable’, having them describe the pain, talking about function, not feeling.

“Words That Matter When Talking About Pain With Your Doctor” – Patti Neighmond

Unfortunately, mental health doesn’t always get the recognition it needs (although it seems things are getting better). This seems to be an issue in sport, as athletes sometimes think they need to ‘tough it through’ a concussion, or other mental health issues. Well, we know this isn’t the case, so the question arises, if there were a simple test that showed a mental health disorder, would we treat it differently?

“What If There Were A Test That Showed The Signs Of A Mental Health Disorder?” – Dr. Tom Ungar

 

Pain Education – How Much Neuroscience Do We Really Need?

Pain education has for many become an integral part of the treatment process and rightly so, being able to help people understand what is happening to them is a must. One of the most frequently used methods to help people better understand pain is based on the neuroscience and physiology of pain.

In some cases, this can be sufficient to help people understand more about pain but is neuroscience ALWAYS required? Many patients may benefit from explanations that do not include information related to these aspects.

Also, does a neuroscience-based approach adequately explain the EXPERIENCE of pain and acknowledge the person EXPERIENCING it?

The neuroscience of pain could be explained in a standard way involving the various bits of neuroanatomy and the associated physiological processes to a room full of people, BUT if we were to interact individually with the PEOPLE in the room we may find that they have wildly varying EXPERIENCES associated with that pain.

Pain As An Experience

So neuroscience may explain how the sensation of pain is created, and many of the oddities that surround it, but does it fully explain the experience? Human beings, after all, are much more than the sum of their parts, and this is what makes us individuals, and does a generic universal explanation imply that pain is all the same? A neuroscience-based approach could be described as an objective view rather than a subjective one, but perhaps it is subjective that seems to most explain the impact of pain on people’s lives.

A question to ponder is that if structural anatomy, and the damage to it, does not adequately explain pain does neuroanatomy and physiology? It certainly pokes holes in the common belief in a simplistic relationship between damage and pain but does it fall short in explaining the experience and the behavioral responses that have such a profound impact on the wellbeing of the person and those around them?

We could take brain imaging or nociceptor firing thresholds or the dorsal horn sensitivity of anyone and display it on a screen, can I differentiate the different experiences that people have by doing so?

From my perspective I want people to know that pain is MORE than just a sensation to be recorded in a score, rating or questionnaire. It is in an experience that can puncture or our existence in many ways and that many parts of our existence can affect our pain experience as well.

Pain is far more than just physical, it affects our overall well-being and emotional state and this is completely NORMAL. For example, our mental health is part of our wellbeing and goes up and down in the same way that physical health does. We often place a much greater stigma on mental health though and we might need to let people know IT IS OK NOT TO BE OK with regards to this facet of their pain experience.

We can feel low, worry about the implications of the pain and have greatly reduced expectations for recovery. These aspects form our individual experience and addressing these aspects for some people could be the key to their recovery.

The common sense model is a great way to start to understand some of the aspects that make up our individual pain representations

Leventhal – HERE

Hale HERE 

Bunzli HERE

Pain Has Meaning

The MEANING that someone associates with pain, the emotions, and changes in behavior, the belief structures, these are the things that make the pain experience unique to the individual. These are the things that differentiate one person’s experience from another and why some can cope whilst others are disabled by pain that might be of a similar intensity.

We could say that neuroscience is merely a process involved in that experience, but instead of putting the person at the forefront of that experience do we now place the therapist and the information they hold as the star of the show?

A very simple analogy ( and please remember that they are never perfect!) I use for helping people understand the different meanings people attribute to pain is that of a Petrol gauge.

We could conceptualize both pain and a petrol gauge as warnings. How we respond to these warnings can be very different. In the case of the petrol gauge some people may be quite comfortable to drive on even though they have the gauge on empty, perhaps they know their car and exactly what it is capable of doing. Someone else may rush to get petrol straight away; their response to the same situation is completely different. Perhaps they have run out of petrol before and remember a bad experience? If we changed the context would that have an impact? Would the comfortable people feel different in someone’s car?

Individualize It

Education should be something we do WITH people rather than something that is done TO people.

One of the key aspects in the clinical encounter is the individual journey that someone has had in relation to their pain. How do we use our increasing knowledge of pain to adequately explain THEIR therapeutic journey, story and ultimately their overall pain experience?

Qualitative research tells us that people crave an explanation for their problems, that they want a diagnosis HERE & HERE. This is often not possible and so a narrative becomes vital and this can often involve learning more about their pain and the way it behaves. There is a huge difference between helping generate an alternative positive personal narrative and just the application of information about pain, however.

Rather than an information dump, the selective use of pain-related information should relate to something that is involved in the dialogue that is occurring between two people. A large criticism of and negative responses to medical interactions appears to be HCP’s not listening to people and talking AT them rather than to them. There is a danger of this with any application of information in a generic way.

This is a fantastic paper on the use of metaphor with people in pain HERE 

Education Has Many Parts

There are many ways in which we can educate people about their experience. Part of this DOES include neuroscience, especially from the perspective of a clinicians understanding of pain. How much of this needs to be part of the educational experience of the person though?

Basic information about a normal timeline for recovery might influence perception and behaviours. Understanding the lack of association between many physical factors and activities and pain might influence perception and behaviours. There is a recent example of back pain HERE

Some of the factors that are associated with worse outcomes in back pain, such as increased passive coping and low self-efficacy HERE, might actually help change behaviour. Informing people that THEY are the key to their own recovery!

There are many ways in which we can educate people that don’t involve the neuroscience of pain.

Creating A Positive Experience

Regardless of what type of information provided, the most important thing is to create a positive experience for the person and to try to describe pain as a positive part of the human experience. After all, you would not want to live without it!

Another very simple analogy I use, and of course is context dependent, is to compare pain to red wine. A glass of red wine for many is a good experience but have a bottle instead of a glass and that can be too much of a good thing, especially the next day. We would like pain at the appropriate times and the appropriate levels.

With the biopsychosocial model we are opening up many new therapeutic influences and targets for treatments but amongst all these problems we can also work on things that are positive within peoples lives and in negative times, such as during pain, this may be a great way to alter someone’s current experience. This is a fantastic paper on focusing on resilience and sustainability HERE.

 

As a recap, these are some key patient messages (IMHO of course)

  • Pain is an experience, not just a sensation
  • It is more than just physical it affects our well-being and emotional state and that is NORMAL.
  • It may become more about these affective factors as it persists.
  • The way that we think and feel directly effects recovery
  • Human beings are very complex and much more than anatomy that becomes damaged or even sensitized.
  • Focus on positives factors, not just negatives ones.

 

Critical Thinking For A Deep Vein Thrombosis

He came in complaining of extreme calf pain.

Everything seemed pretty straightforward, health history seemed fine, no real mechanism of injury, but it just seemed odd.

I tried doing the Homan’s sign orthopedic test but honestly couldn’t tell if I got a negative or a positive result because neither seemed very clear.

After three treatments it didn’t seem to be getting much better. We made an appointment for the following week but he didn’t show up, I kind of freaked out a little.

Did he have a DVT and I missed it?

I’ve only seen a case like this a couple of times and honestly to this day am not sure if I have ever done the orthopedic test properly because it never seemed really clear each time I tried it.

Deep Vein Thrombosis

If you’ve never heard of it, or are not sure what I’m talking about when referring to a DVT, it stands for “Deep Vein Thrombosis,” which is the formation of a blood clot in the lower limb. 

The big issue with this is if the clot dislodges it can become a pulmonary embolism blocking blood vessels in the lung, which, depending on the size of the clot could be life-threatening. If it is a smaller size clot, at a minimum it can cause damage to the lungs.

So, how do we know if this is what our patient has when they come in complaining of pain in the lower legs?

Well, first off we need to get a good thorough health history from the patient. When we look at the causes of a DVT, you could easily ask some questions that would throw up some red flags as an indicator without even observing the area of complaint. Some of the risk factors that cause a DVT include:

  • Family history of DVT.
  • Overweight or obese.
  • Damage to blood vessels:
    • broken bones
    • severe muscle damage
    • during surgery
    • varicose veins
    • vasculitis
  • Conditions that cause blood to clot more readily:
    • cancer
    • heart and lung disease
    • thrombophilia
    • Hughes syndrome (an immune disease that causes increased clotting)
  • Being inactive or immobile for extended periods:
    • Sitting for extended periods on a plane during travel (this is an important one)
    • long duration surgeries
  • Pregnancy.
  • Women on birth control or hormone replacement therapy.

Think about turning all of the above factors into questions during your intake. If your patient reports any of the above it’s a good sign to investigate a little deeper before progressing with your treatment. It is also worth noting, this typically happens unilaterally, so hopefully, only one side is of concern. 

If you get to the point of doing an assessment on the painful area some of the symptoms look like:

  • Heavy ache.
  • Pain, swelling, and tenderness in the area.
  • Red, warm skin, especially around the back of the leg close to the knee.

We were taught an orthopedic test in school called “Homans Sign”. From memory, you were supposed to squeeze the gastrocs while the knee on the affected side was bent and have the person dorsiflex their ankle. I have only known two people in my life who have been diagnosed with this, both told me that in their case the pain was so bad, there is no way they would have let someone do that to them (and yes I realize this is anecdotal evidence, but I thought it worth the share).

However, this test has come under some scrutiny lately. One study showed Homan’s sign was positive in 33% of patients with an actual DVT, but also in 21% of the patients who had no thrombosis. The estimated accuracy of the test ranges from 8% to 56% and also positive in more than 50% of patients who were symptomatic but did not have a DVT. So, it’s fair to say this orthopedic test is not a reliable test for us to use. 

In researching for this post I came to understand there is also occurrences of upper limb DVT’s, which can affect any veins of the upper extremity or thoracic inlet, including; jugular, brachiocephalic, subclavian, and axillary veins as well as the more distal brachial, ulnar, and radial veins.

Some of the risk factors in this case include: 

  • High body mass index.
  • Pregnancy.
  • Surgery.
  • Smoking.
  • Malignancy.
  • Foreign body in the vascular system (more than half the patients who had this, was because of pacemaker).

The more typical signs and symptoms are:

  • Swelling. 
  • Pain.
  • Edema. 
  • Cyanosis.

Some other symptoms like localized neck and shoulder pain, weakness, paresthesia, and elevated body temperature can occur but are less likely. 

Yet, another reason why our clinical reasoning has to be used when interviewing our patients. If we see any combination of the above signs and symptoms mentioned for lower or upper limb DVT, we MUST at a minimum refer out to a doctor, but more likely to the hospital to be sure of an accurate diagnosis, and of course to ensure patient safety. 

The Skilled Therapist

The whole reason behind this post was because of an article being shared around regarding DVT. 

It is the story of a 53-year-old woman who presented to a clinician with worsening shortness of breath, history of smoking and hypertension. Upon further investigation, they found increased calf muscle soreness over the previous two weeks after having an aggressive massage done while getting a pedicure. 

After more assessment, it showed defects in several pulmonary arteries and examination of the lower extremity suggested residual deep vein thrombosis. 

Fortunately, the article acknowledged that for this story and another one mentioned, the massage was being done by a layperson, not a skilled therapist, and massage was only partially responsible for the outcome. 

Now, I get it, we spend a lot of time on this site busting some massage therapy myths, however, this one is no myth. We actually want to reinforce the importance of this message. Note the article points out a skilled therapist was not involved. Well, I firmly believe that if you’ve been following this blog for any length of time YOU are a skilled therapist. Whether this is new information to you or just a review, it’s important to recognize those signs and symptoms and be able to communicate effectively with your patient in case you do need to refer them out because this is a medical emergency and should be treated as such. 

Predictive Coding: Why Expectation Matters For Movement And Pain

 

Predictive coding is a hip new model for perception that I have been studying lately. In some ways, it is very common sense and intuitive, and in others, it is very challenging and mind-expanding. Here’s a post describing what I’ve learned that I find interesting and practical. Before getting into that, let’s review why any of this should be interesting to anyone concerned with movement and pain.

First, good movement requires good perception. The skill of moving your body with coordination is inseparable from the skill of perceiving where your body is in space and how it is moving. We perceive to move and move to perceive, and that is why we often say that great movers have amazing “body sense” or “proprioception.”

Second, pain is in the nature of a perception. It depends on the brain’s interpretation of whether the body is in danger and what needs to be done to protect it. If your foot hurts, that means your brain perceives, rightly or wrongly, that it is damaged. Perceptions about the body (like anything else) can be mistaken, which is why we can have pain in areas that aren’t damaged, and damage in areas that aren’t painful. By learning more about the science of perception, we necessarily learn more about pain and how to treat it. 

The Conventional Model For Perception: Bottoms Up

The conventional model of perception works roughly as follows. We collect sensory information through nerve endings in the eyes, ears, skin, muscles, etc. This information is relayed to the brain, which processes the information, interprets its meaning, and then creates a perception about the cause.

For example, when I see my wife’s face in front of me, this is because light bounced off her face, the pattern of the light was registered by my eyes and sent to my brain, which recognized the pattern as coming from my wife’s face, so it created the perception of her being there (so I would know who to take orders from.)

Or, if someone feels pain in their knee when they take a step, this is because the mechanical force of the step triggered nociception (nerve signals about potential damage), the signals reached the brain, the brain concluded the knee was under threat, and it created pain to encourage protection (maybe by limping). This model is therefore very “bottom-up” or “outside-in.”

It emphasizes the flow of information from the outside world to the periphery of the body, and then from the periphery to the brain. What’s missing from this story? What the model fails to explain very well is the role of past experience in determining how the brain interprets the meaning of the incoming sensory information. 

This is where the predictive coding model adds value – it explains how “top-down” factors modify incoming sensory input.

Predictive Coding: Expectation Matters

According to the predictive coding model, the brain is always building and refining its representations or models of the outside world (and our bodies). Our perceptions depend in large part on these models, not just incoming sensory data.

For example, I have an internal model of my house that includes only one four-legged creature – my dog Levi. So if I walked through the living room in low lighting and glanced at a wolf, I would probably literally see my dog, Levi. In other words, my perception would be determined by more by my expectations than by actual sensory data from my eyes.

Check out the pictures below for some other examples of how expectation can determine perception.

 

In the first two images, you perceived something very different from what your eyes told you, based on your prior assumptions about how words are usually ordered or spelled. In the third picture, you saw two normal looking faces, based on your prior experiences with face parts being arranged in certain ways. (Turn the picture upside down to see a very different arrangement.) 

This happens with many other kinds of sensations. If you think satanic messages are hidden in rock lyrics, you can hear them if you play Stairway to Heaven backwards. If you come up from behind someone and say “hot!” at the same time you put ice on their arm, they will feel heat. The painkilling effect of a placebo is based purely on the expectation that it will reduce pain. And nocebos work the opposite way – expecting pain can cause pain. To some extent, we perceive what we predict.

Comparing Top-Down to Bottom-Up 

The predictive coding model has a great explanation for exactly how expectation affects perception.

The nervous system is arranged in a hierarchical fashion with the brain cortexes at the top and nerve endings at the bottom. Higher levels of the nervous system are constantly predicting the incoming flow of sensory data from lower levels. These predictions create a neural activity that flows downward (top-down) to meet incoming sensory data (bottom-up).

When the meeting occurs, a comparison is made between what has been predicted and what has been sensed and this generates a prediction error. Put another way, top-down “shakes hands” with bottom-up, and disagreements are discussed and compromises are struck. If the error (or disagreement) is relatively small, it is disregarded as being random noise or “close enough.”

Higher levels of the nervous system are not informed of their prediction errors, and the world is perceived exactly as expected. If the error is large, higher levels are notified of their mistake so they can update their model of the world. This creates a subjective feeling that something surprising or important has happened, and attention is automatically shifted to the incoming sensory data so that perception and action can be adjusted accordingly. 

The strength or confidence of the prediction has a big effect on how prediction errors are treated.

If the prediction about incoming sensory data is highly confident, (perhaps based on tons of past experience) even significant errors will get ignored. But if the prediction is not confident (perhaps because the context is novel and errors are anticipated), then bottom-up sensory information has a better chance of ascending to higher levels of the nervous system and causing changes in perception.

Attention also matters for how prediction errors get processed.

If I pay attention to a certain stream of sensory information, it increases the chance that prediction errors will be noticed and not dismissed. The system can, therefore, bias perception in favor of top-down or bottom-up factors based on relative levels of confidence or attention to either one. For example, according to my model of the world, the only black SUV in my garage is my car. If you switched it for another one, I would probably get in without even noticing. My perception would be controlled by expectation, not the information from my eyes. But I wouldn’t suffer the same illusion in a crowded parking lot where my perceptions would be controlled far more by bottom-up sensation than top-down prediction.

Now that we have a basic understanding of how this model works, let’s look at how it explains some common and not so common phenomena related to perception.

Pain

The predictive coding framework helps explain why pain is affected by past experiences, thoughts, expectations, and emotions, and not just tissue damage.

For example, if you have a good deal of experience where flexing your low back causes pain, you will start to build an internal model of your back that predicts it will hurt with flexion. This will strongly bias you to feel pain each time you bend, even if the back isn’t actually producing that much nociception. 

You can reduce the contribution of top-down factors to your pain by updating the model of your back. To do this, you need to cause a prediction error by violating your expectation that bending will hurt.

A good strategy would be to perform low back flexion in some novel way, perhaps in quadruped or supine, while paying attention to how it feels while bending so that any predictions errors are not disregarded. That sounds like a high percentage of movement therapy in a nutshell.

A more aggressive and risky strategy would be to perform some movement where the back muscles have to work very hard to prevent flexion, say a heavy deadlift. Perhaps you do the deadlifts with good form to prevent flexion. It hurts a little, but nowhere near as much as you expected. In fact, you have a visceral feeling of surprise at how strong you feel. This is evidence that you have violated an expectation that your back was too weak and fragile to handle any significant force, and that your map for the back is being updated to account for the prediction error. Good sign!

The bottom line is this – a great deal of what can help with pain in the short term is violating an expectation that something will hurt. There’s probably a lot of ways to do that – massage, deadlifts, cat-cows, stretching, isometric resistance exercise, active or assisted joint mobility exercises. What they all have in common (if they help with pain) is that they don’t hurt as much as you would expect.

Moving Better – Prediction And Action 

According to the predictive coding model, there is a profound connection between perception and movement, because each can help correct a prediction error, and minimizing error is really all the system cares about.

When the system is confronted with a prediction error, it can do one of two things – update models to reflect the new information (change perception) or alter action in a way that gathers sensory information consistent with the prediction (change movement).

For example, let’s say I am squatting to a box with my a barbell on my back. When I squat to a certain depth I expect sensory feedback from my butt indicating touchdown. But there is a prediction error – my butt is silent. I can do one of two things – I can change my perception about the location of the box (oops I forgot to put it in place!) Or I could change my action – move my butt a bit lower or further back until I get the predicted feedback.

So one way or the other, the essential goal is always to reduce prediction error, and it doesn’t really matter whether that is done by changing perception or action. The important thing is that I don’t crash to the ground with a barbell on my back. Either way, good internal models and good predictions are the basis for generating functional perceptions and actions. 

Getting better at movement is therefore very much about improving your internal models for movement and your predictions for what kind of sensory feedback you will get during the movement. This means you need a lot of experience, you need to make mistakes, and you need to pay attention to the right streams of sensory information to identify and correct those mistakes through better perceptions and actions.

Of course, we know most of these things anyway, but I think it’s cool to see that application of the predictive coding framework gets us to the right answers. Here’s some cool stuff that we might learn from predictive coding that we don’t already know and is not easily explained by other models. 

Schizophrenia, Autism And Babies 

Check out this picture of Albert Einstein – is his nose closer to you or further away?

We expect noses to be closer to us, so most people will see this mask as being convex when it is in fact concave.

Interestingly, schizophrenics (and people stoned on marijuana) are actually less likely to make this mistake. This might be because their perceptions are controlled more by bottom-up sensation than top-down models of the world. And maybe this is why they can both tend towards paranoia. Schizophrenia involves delusions where everyday events are regarded as incredibly salient and important.

Imagine sitting in a crowded coffee shop and hearing your name in a nearby conversation. This might get your attention, but it would not probably register in your consciousness as being profoundly surprising.

But if you had a problem whereby the relevance of unpredicted incoming sensory information was massively magnified, then the mention of your name might feel profoundly important, and perhaps contribute to delusions of reference or paranoia. So perhaps paranoid delusions involve assigning too much importance to minor errors in prediction. 

Autism can be also be understood as a condition where bottom-up sensation dominates top-down predictions. Even the smallest prediction errors are considered important.

Thus, all incoming sensory information is regarded as “newsworthy” and people with autism are “slaves to sensation”, constantly distracted or irritated by minor inputs like labels on their clothes, or random noises. Interestingly, people with autism often self-soothe by engaging in repetitive rhythmic movements. These create a stream of sensory information that is highly predictable. Better prediction allows the suppression of sensory information that would otherwise be overwhelming.

Maybe this is why babies like rhythmic movements, or to be carried around all the time, or to be swaddled. Because they don’t have much experience in the world, they have no strong internal models to create confident predictions about their incoming sense data, and they just get blown away by all of the information they are getting about the unpredictable movements of their arms and legs, the variations in the way their back is touching the car seat, and the random noises created by the TV, traffic, etc.

Adults are exposed to all of this information too, but we can easily predict it and therefore ignore it. But for babies without good internal models of the world, everything is a blooming, buzzing confusion. Perhaps they are soothed by getting a nice stream of predictable rhythmic sensory information. Aren’t we all? Lots of interesting food for thought here. Here are some further resources if you want to learn more. 

Good Articles On Predictive Coding

An Aberrant Precision Account of Autism

Prediction error minimization: Implications for Embodied Cognition and the Extended Mind Hypothesis

Active Interoceptive Inference and the Emotional Brain

The Hard Problem of Consciousness is a Distraction From the Real One

It’s Bayes All the Way Up

(Thanks to Derek Griffin and Mick Thacker for linking many of these.)