Pain is like Memory: Dr. Jay Joshi on Central Sensitization

Okay.  I’ve really been looking forward to publishing this post.

Here, we’re revisiting the same great talk by pain physician Dr. Jay Joshi.  In my last post, I outlined what Dr. Joshi says are the four main categories of pain.

Central sensitization is the type that is, unfortunately, the least understood.  And it’s also the type that’s had the biggest impact on my life to date.

What is it?

Central sensitization is a process through which the central nervous system learns to become more sensitive to, or amplify, pain signals.

I struggled with it for years and thought I was crazy, because I had pain that came and went throughout my own body that most of the doctors and physical therapists I saw couldn’t explain.

Central sensitization is a form of memory.

Generally, we think of central sensitization as a sort of a disorder, because of course, it causes so much pain and suffering.

However, as I’ve touched upon in previous posts, central sensitization actually has its roots in some of the same neural mechanisms that allow us to learn new things and store memories.  We “learn” from pain just as we learn from anything else, and our nervous systems can be changed by it.

As Dr. Joshi says:

“Central sensitization is what happens when the brain is exposed to certain experiences or certain memories.  It’s life… it’s being a human.

When you have a certain memory that forms it, becomes part of who you are… it becomes part of your experience.  And your behavior changes as a result of that.

This is not something that happens randomly…  This is something that happens to the neurophysiology of your brain.  It forms memories.  Those circuits get hardwired on your little ‘hard drive’ that’s known as a brain.  The same thing that happens with pain, when you have a chronic pain stimulus.”

The process of central sensitization is not separate from our brain’s other functions– rather, it belongs to them.

I found this happened to me so often, over the years, before I even knew what central sensitization was.

I’d have a painful experience– the first one was when I threw my back out at age 21— and it was like my nervous system was determined not to let me forget about it afterwards.

According to Dr. Joshi, this is exactly how central sensitization occurs, after a painful or traumatic event:

“You have a painful experience, and usually one of the first things that happens is your brain says ‘hey don’t do that again.'”

It’s trying to protect you from doing the same thing that might have caused you to become injured in the first place.

But what happens when that signal doesn’t stop? 

In cases like mine, this process can go on indefinitely.  Your brain keeps trying to protect you, telling you not to repeat certain activities, long past what’s actually necessary or conducive to your well-being.

This is called the wind-up phenomenon— when the brain’s protective mode stays on, and never gets the signal to turn “off” like it should.  Instead, it just keeps repeating the message of “don’t do that again”– even if it’s something that, technically, should be safe for you to do.

Once this process, the pain can sort of build on itself, like a snowball effect.  And you can remain in pain, long after the original injury that might have set all this off as healed.

Does all chronic pain cause central sensitization?

Dr. Joshi explains that chronic pain is likely to lead to some degree of central sensitization.  (This is significantly higher than other estimates I’ve heard, such as Dr. Elliot Krane’s figure of 10%).

However, I think Dr. Joshi’s explanation makes a lot of sense.  After all, when you experience chronic pain, you’re basically bombarding your nervous system with opportunities to practice sending pain signals.  Why wouldn’t it get better at doing so, the same way you can get better at playing the piano or riding a bike?

Central sensitization is still a part of my life.

I don’t expect to ever be able to totally reverse the process that first began, for me, at age 21.

However, I was able to make a lot of positive changes and gain back a lot of control over my body through pain neurophysiology education, which I write about a lot on this blog.  (Basically, it involves teaching your nervous system what it’s like to feel safe again, so that it can turn the “volume” back down on the pain).

There’s a lot more to say!

Dr. Joshi has some great thoughts on how to improve the medical profession’s understanding of central sensitization, as well as ketamine infusions– a potentially powerful treatment for patients with central sensitization.

I’ll be sharing more on this coming up– hope you liked this post!

Learning about central sensitization: the power of naming, and the future of pain treatment

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Whew.

I have really enjoyed writing my more personal posts recently– I love to tell a good story, and to feel as though my past experiences have some meaning.  (And I’ve really appreciated all your kind words, comments, and shares!).

But also, wow– some of those posts were very emotional for me.  Right now I’m kind of feeling the need to come up for some air.

So let me back up for just for a minute, and talk about some of the things I’m optimistic about, in terms of the big picture in treating chronic pain.

The more we know about central sensitization and the way pain works:

It gives us the power to name things.  

This is something I’ve been thinking a lot about recently.  Sometimes, there is a healing power that comes just from being able to put a name to something; to receive a diagnosis, and know that you aren’t the only one.

As I explained in my last post, when I finally learned the term central sensitization, it helped me to feel validated, and so much less alone.

Sometimes healing can come not from completely “fixing” your condition, but from being able to make meaning out of it for yourself; constructing a coherent narrative that makes sense.

And of course, it’s much easier to make sense out of something when you actually know what it is.

Having an actual diagnosis can help us explain ourselves to others

At least, I assume it does.

As I have mentioned in past posts, the truth is that I have often struggled to articulate what’s happened to me in the people in my life.

Of course, it didn’t help that I didn’t really have an explanation that made sense for it myself, for most of the time, or that even now that I have an explanation, it’s a condition that’s still fairly unknown.

This is why I am doing my best to raise awareness and get the word out.

The more we, as a society, understand about pain, the more treatments we can develop.

There is just so much to say here.  The more I learn about pain, the more and more I realize I don’t know.  It’s really such a fascinating subject.  I try to talk about some of the highlights on my blog, just to give you a sense of how broad the subject really is.

But in a nutshell, our growing scientific understanding of pain can lead us to all sorts of new treatments, such as:

New pharmacological approaches: I’ve recently discovered Gracie Gean’s Youtube channel, and her story about receiving ketamine infusions to treat CRPS.  I totally recommend checking it out!

Brain imaging and biofeedback: I’ve written before about the work of Christopher deCharms and others at Stanford University, who use functional MRI to teach patients to mentally “turn the volume down” on their pain.

Pain neurophysiology education

And of course, once you understand that pain is one of your body’s protective responses– it’s actually there to keep you safe, not make you miserable– this can help you learn to work with it, not against it.

This is the premise of pain neurophysiology education, which I talk about in the “Calming Your Nervous System” section of my blog.

When I was in the midst of my struggle, I happened to find a physical therapist who had taken a PNE course with Neil Pearson, and that was the moment things really changed for me.

I learned to view my pain not as an automatic indicator that something was wrong or broken in my body, but as my body’s attempts to protect me.  And, each time something hurt, it was possible my body was overreacting, like a jumpy alarm system, or an overprotective friend.

This helped me to mentally take a step back when things began to hurt, and re-evaluate what I intellectually thought the pain was likely to mean.  And even just realizing that I had the ability to do this– that pain didn’t always have to mean something was wrong– helped me to begin to end the cycle I’d been caught in.

So, that’s all for now.

I’ve got a bunch of posts planned for the next few weeks that I’m really excited about.

I’ve also recorded a podcast interview with Matthew Villegas for The Capable Body Podcast about my experience with pain neurophysiology education.  Although I was afraid I sounded super awkward, Matt assures me the episode will be good!  It should be coming out sometime in September– I’ll be sure to let you know when it does.

Stay tuned!

 

 

Shedding light on central sensitization

Hi everyone!  Hope you’re all having a great summer.

I just wanted to let you know that I recently added a new section to my blog, to focus on central sensitization.

When I began this blog in late 2012, I started out writing about the topics of chronic pain and fibromyalgia, terms which most of my readers are more familiar with.

However, over time, it became more and more important to me to focus on some of the scientific research that’s been shedding light on the nervous system phenomena behind chronic, persistent pain.

Central sensitization has had a huge impact on my own life, one that’s stretched far beyond the initial injuries that caused me to develop it in the first place.  (Basically, central sensitization occurs as a response to some sort of trauma to the body, leaving the person with a heightened sensitivity to pain long after any physical injuries have healed).

I’ve recently begun to tell the story of “How I developed central sensitization.”  It’s a series posts about how, after years of abusing my body as a high school athlete with an eating disorder, I finally stretched my nervous system to the breaking point.

I’ve also written a series on my experience with pain neurophysiology education, an approach to physical therapy that taught me to better manage my condition.

These stories are incredibly personal to me, yet I really believe that central sensitization is an under-recognized problem, and I’m determined to raise awareness.  It took me years of suffering before I even knew the name of my condition (or was able to get help treating it), and it shouldn’t have to be that way.

So on my blog, I’ll be telling stories from my own personal experience, well as highlighting some of the articles, research and researchers that I find inspiring and noteworthy.

I’ll still be writing about chronic pain and fibromyalgia, recognizing that there are many factors that contribute to each patient’s experience with these conditions.

Ultimately, I believe that the more we know as patients, the better we can advocate for ourselves.  That is why I believe so strongly in raising awareness of this issue, both in terms of the scientific discoveries being made, as well as sharing the impact it’s had on my own life.

Here are some of the posts I’ve written on central sensitization so far:

What is central sensitization?

The nervous system and chronic pain

How I developed central sensitization: Part 1

How I developed central sensitization: Part 2

How Clifford Woolf discovered central sensitization (and why you shouldn’t blame yourself for chronic pain)

Central Sensitivity Syndromes

Todd Hargrove: Seven Things You Should Know About about Pain Science

Let’s give this a whirl: explaining a scientific article in plain English

All of these, of course, are listed on my new “Central Sensitization” page.

Other great links:

Central sensitization in chronic pain (from Paul Ingraham at PainScience.com)

Dr. Sean Mackey: An Update on Fibromyalgia (really interesting talk from a Stanford researcher on the role of central sensitization in fibromyalgia).

and a lot more within my “Resources” section (if you haven’t swung by in a while, I’ve been adding a lot to it).

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I hope the things I write and link to are helpful to you.  As always, you’re welcome to contact me with any comments or questions.   (You can comment below or send me an email!).  Happy reading!

How Clifford Woolf discovered central sensitization (and why you shouldn’t blame yourself for chronic pain)

You’ve probably noticed that my blog is all about central sensitization— the process through which the central nervous system can change over time and become more sensitive to pain.

Personally, I find learning about central sensitization to be empowering.  I spent years trying to find an answer for the pain and other symptoms I felt, only to be told by various medical professionals that my problems were in my head, the possible result of depression or anxiety.

I knew, deep down, that this just wasn’t true.  It’s not that I was unwilling to believe that mental health factors could play a role.  But it just didn’t resonate. I didn’t feel anxious or depressed.  I felt like I was in pain, and wanted it to stop.

That’s why, when I first heard the phrase central sensitization and looked up what it meant, I was so struck.  Because there was a way to explain why my nervous system was acting funny, and causing me to feel things other people didn’t feel, that wasn’t based on my mental health.

So.  How do we know about central sensitization?

A neuroscientist named Clifford Woolf discovered the process of central sensitization back in the early 1980’s.  In 1983, he published a well-known and often-cited letter to the respected scientific journal Nature outlining his theory, entitled “Evidence for a central component of post-injury pain hypersensitivity.”

Although the scientific community didn’t quite accept Woolf’s ideas right away, ultimately he ended up sparking a new wave of research, and his theory of central sensitization is generally accepted today (although much more work still needs to be done).

Basically Woolf ended up discovering central sensitization more or less by accident, in the process of researching something else.

(Now, I’m not a huge fan of animal research, so I don’t love what I’m about to describe to you.  But I am grateful for the results, so for the sake of understanding, here we go).

Woolf was studying the “withdrawal reflex” that caused the rats to jerk their paws away from a painful stimulus.  He tested them over and over again, over the course of a day, and he noticed that he started to get different results at the end of the day.

After a long day of testing, the same rats were much jumpier.  It became much easier to trigger their withdrawal reflex.  They would jerk their paws away even at things that shouldn’t have been painful, or wouldn’t have caused them to react that way at the start of the day.

Woolf realized he was seeing completely different behavior in the same rats, and under the exact same conditions.  Only one thing had changed: their nervous systems had been “practicing” the withdrawal reflex all day long, and were now responding to stimuli differently.  He hypothesized that somehow, the central nervous system had changed to become more responsive to pain, after exposure to repeated stress.

Woolf’s theory was pretty revolutionary at the time. Generally speaking, the scientific community believed the central nervous system always processed pain the exact same way, like a simple machine performing the same task over and over.  Woolf’s discovery turned all of that on its head, by suggesting that actually, the central nervous system can be changed and shaped by its experiences.

His ideas were not widely accepted right away, but his work, along with that of others such as Muhammad Yunus, has now formed the basis for a wide body of research on central sensitization and chronic pain that’s going on today.

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We do still have a long way to go.  Much more research is needed, not to mention new treatments to be based on that research.

However, the reason I wanted to go into detail and describe the rat experiment for you guys is this:

If you have chronic pain/fibromyalgia, people are going to tell you it’s in your head.  Unfortunately, even sometimes people who have a passing understanding of central sensitization will imply tell you it’s in your head.  In my experience, people can understand the concept of the nervous system working differently in principle, yet still think it must somehow be related to mental health.

So this is what I want you to know: central sensitization happens in rats.

Your thoughts, beliefs, and fears about pain, and your mood– those can all play a role in your experience of central sensitization/chronic pain.

But those things don’t cause central sensitization, any more than they did in the rats in Clifford Woolf’s lab.

Remember that the next time you feel someone isn’t taking you seriously.  You can’t create your whole experience of pain by “overthinking” any more than a rat can overthink something.

In some ways, your nervous system is its own being.  There are aspects of your nervous system which have way more in common with a rat nervous system than with your conscious, human mind.  (I know, think about that!  That’s evolution for ya).

So if you have chronic pain, don’t blame yourself.  Don’t scold yourself for overthinking; don’t wonder if you’re crazy.  Your body is just doing what it was always going to do, in response to whatever stress/pain/injury you experienced.

There are ways to move forward– promising ways, which I talk about on this blog.

But to me, the first step is to stop blaming yourself.   You are okay.  You didn’t cause your own central sensitization, any more than the rats caused what Clifford Woolf observed in the lab.

Let’s give this a whirl: explaining a scientific article in plain English

Tonight, I’m going to try out a type of post I’ve been wanting to write for a while: taking a scientific journal article on central sensitization, and translating it into plain English for my readers.

I got the idea from Paul Ingraham of PainScience.com.  He has a fantastic “jargon-to-English” article on central sensitization on his site (a translation of a paper by renowned pain researcher Clifford Woolf), which I really love.

There is no reason why you, as a patient and chronic pain sufferer, should not be able to know a little bit about the scientific research being done on your condition.  You are going to need to be able to advocate for yourself, stand up for yourself, and remember there is a legitimate explanation for your pain, even if other people don’t always see it that way.  Knowing there is research to back you up helps.

Ever since I first learned of the term “central sensitization” back in 2011, I found so much comfort in reading these articles.  Even if I didn’t understand every word, just knowing there were people out there who would believe me about my pain, if I met them, provided me with the sense that I wasn’t alone.

These changes to our nervous systems are real, even if some of the people in our lives don’t always understand.

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So anyway.  The article that I want to take a stab at tonight is “Central Sensitization: A Generator of Pain Hypersensitivity by Central Neural Plasticity” by Alban Latremoliere and Clifford J. Woolf.  (In the interest of keeping things manageable, I am just going to outline the abstract, which is basically a summary of the article).

The article discusses central sensitization, which is the name of the process through which our nervous systems learn to become more sensitive to pain.

Let’s look at it in bits and pieces:

“Central sensitization represents an enhancement in the function of neurons and circuits in nociceptive pathways caused by increases in membrane excitability and synaptic efficacy as well as to reduced inhibition…”

This basically means that the parts of the nervous system responsible for sending pain signals become more active than they were before.

“Increases in membrane excitability” means that it will take less stimulation for nerves to send a pain signal.

An increase in “synaptic efficacy” means that the nerve is going to learn to be more efficient with the neurotransmitters that it has.  So, even though the nervous system still has the same chemicals floating around in it, it is going to learn to start sending stronger and stronger pain signals with those same chemicals.

Reduced inhibition.   Your body has many intricate systems of checks and balances within it.  It is how our bodies maintain control over our internal environment.

One way our body maintains control is by “inhibiting” some of the signals our nervous system sends.  This serves a really practical purpose– we do not need to be bombarded with reminders that our socks are a little bit itchy at all times.  Your nervous system chooses to block out certain signals when they are not useful, or in emergency situations (which is why people can feel no pain when they are in shock).

But in the case of central sensitization, our body’s ability to “block out” or “turn the volume down” on pain signals is reduced, meaning we ultimately experience more pain.

“Central sensitization is responsible for many of the temporal, spatial, and threshold changes in pain sensibility…”.

There are several ways in which these changes to our nervous systems manifest themselves.

We may find that, when something happens that we find painful, we end up experiencing it as painful in a larger part of our body than we might have otherwise.

I’ve really found this to be true with back pain.  When my back pain was at its absolute worst (before I discovered pain neurophysiology education) one tight muscle or muscle knot could make my entire back hurt.

“Because central sensitization results from changes in the properties of neurons in the central nervous system, the pain is no longer coupled, as acute nociceptive pain is, to the presence, intensity, or duration of noxious peripheral stimuli.”

This means that, in a sensitized nervous system, pain is no longer an accurate measure of the presence of an injury, or the degree to which our tissues may have been damaged by an injury.  The central nervous system is now doing its own thing, and you can’t really go by the pain to know what’s wrong.

“Instead, central sensitization produces pain hypersensitivity by changing the sensory response elicited by normal inputs, including those that usually evoke innocuous sensations.”

This means that we now start to feel pain in response to things that are not harmful, and which would have felt painful to us before.

To give you an example, I once knew someone who also suffered from chronic pain, and she said there were days she simply could not bear the feeling of clothing against her skin.  Just the feeling of a lightweight sweater against the skin of her chest made it burn and throb.

This person wasn’t crazy.  She knew her clothes weren’t “hurting” her.  But her nervous system was reacting as though those clothes were somehow damaging her skin.  There was a disconnect between her rational mind, which knew it was only clothing, and the parts of her nervous system which were contributing to her pain hypersensitivity.

(So… lest I end the post on a gloomy note, not to worry.  That’s where pain neurophysiology education comes in, to try to fix this disconnect).

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Phew.  Okay.  That was not quite as easy as I thought it would be, all the times I thought about writing this post.  But hopefully you made it through!

Everything I write on this subject is meant to be a trial, of sorts.  I’m experimenting with what types of stories and explanations make the most sense, because I really have it in my heart of hearts to develop a set of educational materials on these nervous system changes.

So I want to see what works– what makes sense, what resonates.  (And what doesn’t).

I suffered for so long, thinking I was crazy, when the whole time there were answers out there.  And there was no good reason for it, except that most people (including many medical professionals) still do not know anything about central sensitization.

So I, and my blog, and my future potential physical therapy practice, are hopefully going to be doing something about that.

Please let me know if you have any questions, or any feedback on what sorts of things would be helpful in the future!  I do take requests!