Central Sensitivity Syndromes

A really important concept for anyone struggling with chronic pain, fibromyalgia, or other chronic health conditions is the idea of “central sensitivity syndromes” (CSS for short).

The term refers to any kind of condition that can be caused by a change in the way the nervous system processes pain (a process known as central sensitization).

I have described central sensitization in more detail in other posts.  (Here, I will just say that sometimes, the nervous system can begin to function differently after physical injury or trauma.  Basically, the more chances our nervous system has to “practice” sending pain signals, the better it gets at it).

Central sensitization is why you can still have pain after an injury is healed.  Your tissues are no longer damaged, but your nervous system has not forgotten the “memory” of the pain.

So… how does this happen?  What kinds of injuries or traumas are necessary to cause it?  And what symptoms can it cause?

The answer to is: central sensitization can happen in many different ways, and sometimes the things that trigger it don’t have to be very “severe.”  And there can be a wide range of symptoms, in different parts of the body.   It can be different for each individual person, depending on genetic makeup, co-existing health conditions, psychology, and, of course, the event that triggered it.

This is why the term “central sensitivity syndromes” is so helpful– there are so many health conditions, which on the surface might seem very different, yet all have central sensitization as their root cause.

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To my knowledge, the term was first coined by physician and researcher Muhummad Yunus, who, along with his colleagues, conducted an important 1981 study linking fibromyalgia to other health conditions caused by nervous system sensitization.

Since then. Dr. Yunus has contributed to a really impressive list of studies establishing central sensitization as the likely cause of a wide range of conditions, including:

  • fibromyalgia
  • irritable bowel syndrome
  • temporomandibular disorder (TMJ)
  • restless legs syndrome
  • chronic fatigue syndrome
  • complex regional pain syndrome (CRPS)
  • chronic pelvic pain
  • migraine

Central sensitization can create different types of symptoms, from one person to another, in different parts of the body.   This one common cause can have many different manifestations.

Additionally, as Dr. Yunus writes, central sensitization can occur when someone has another health condition which creates pain and stresses their nervous system.  Central sensitization can be a resulting secondary factor in conditions such as:

  • rheumatoid arthritis
  • systemic lupus
  • ankylosing spondylitis
  • osteoarthritis
  • diabetes mellitus
  • inflammatory bowel disease

Basically, anything that stresses your nervous system out and gives it a chance to practice sending those pain signals can cause it to become better at sending those pain signals.  So even if central sensitization isn’t the primary cause of your illness, over time it can become a secondary factor.

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The good news, however, is that the effects of central sensitization don’t have to be permanent.  It can also get better.

That’s what my blog is all about– helping people find out about the ways I, personally, have managed to reduce the effect central sensitization has upon my life, as well as raising awareness about new avenues of research.

What helped me the most is an approach to physical therapy known as pain neurophysiology education.  However, there are other forms of treatment out there, including medications some people have found to be effective for the effects of central sensitization.

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I’m going to write more on central sensitization and its treatment, as well as the work of Dr. Muhammad Yunus, in the future.

I hope this post was helpful for you, and that you stay tuned!

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.

How I’ve (Mostly) Made Sense of My Issues

Of course, I’m not saying everything is perfect now.  But I’m definitely way better off than I was a few years ago, and a lot of that has to do with how I’ve changed my perspective on pain.

Two important ways in which my thinking changed:

1) Understanding that not all pain comes from a physical injury.  This helps cut down on the cycle of fear. 

We grow up thinking that pain must automatically mean we are injured.  However, pain is actually a lot more complicated this, especially in the case of someone whose body has been through some sort of trauma.

Pain is the body’s protective mechanism, and sometimes it can go a little bit haywire and “overreact,” causing you to feel more pain than you used to.

(I have written a lot about this in past posts, so I am not going to focus on it as much in this one.  But if you are new to my blog, definitely check out my page on “Calming Your Nervous System” for more!).

2) Learning as much as I can about the body.  

When you are caught in a cycle of chronic pain, when your body’s “alarm bells” seem to be constantly ringing, knowing more about the body can help you turn down the signal.

Pain is a dynamic interplay between the body and the brain.  The body can send signals up to the brain, to determine if action needs to be taken.  The brain can also send signals down to the body asking for more information, if it wonders if the body has been hurt.

When you have a chronic condition, knowing more about your own body can help turn down some of those alarm bells when they start ringing.

Here is an example from my own life:

A few years ago, when I first began to have knee issues, there was one night where I experienced extreme, stabbing pain in one leg.  The pain didn’t make any sense to me—it ran in a diagonal line from the outside of my upper thigh, across my leg, to the inside of my knee.

At the time it really freaked me out.  I had no idea what could cause pain to run in such a diagonal pattern.  Since it wasn’t a muscle, I thought, it must be some kind of serious problem involving a nerve.  Maybe it was even a pinched nerve in my lower back.  I burst into tears, took a ton of Advil, and waited desperately for my next physical therapy appointment.

Well, it turned out that there is muscle that runs diagonally across the knee, along the exact same path that the pain ran that night.

I was simply experiencing a spasm of the sartorius muscle, which runs from the outer thigh to the inner knee.

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Photo credit: Wikipedia. http://en.wikipedia.org/wiki/Sartorius_muscle

If I had known this at the time, I probably would have been able to avoid freaking out so much.

Just because the pain is severe, it doesn’t necessarily mean the condition is severe.

A muscle spasm like that one can be extremely painful, but it isn’t really “dangerous.”  It’s just a sign that the muscle is overworked and you need to rest it and do some stretches.

I know that now, and I’ve definitely had muscle spasms since then.  But none of them have set off the same pain “alarm” bells, and I’m sure that part of that is because, on some level, my body has made peace with the idea of muscles being overworked and needing to rest.  I’m not talking about a conscious process.  It’s something that probably happens below the level of conscious thought.

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Photo credit: Zillafag http://www.flickr.com/photos/zillafag/

Of course, my life isn’t perfect now.  I still have some physical issues (specifically, my ongoing saga with the sacroiliac joint).

But I just don’t seem to have the same overblown, five-alarm-fire response to pain that I used to have.  I think my physical issues are probably worse now, in an objective sense, thanks to the sacroiliac issues that I’ve had for the past two years.

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My nervous system, a few years ago. Thanks to songglod http://www.flickr.com/photos/22643708@N06/

But I am actually in less pain than I was a few years ago, where I went from doctor to doctor, only to be told that nothing was wrong, and it’s largely because I helped to calm my nervous system down.

A calmer nervous system

It’s not that I’ve learned to block out pain, or anything crazy like that.  I’m not saying I have no pain.  I’m just saying that now, I have the pain response of a normal person (or close to it) rather than the extreme, overblown pain response of a few years ago.

Back then, my nervous system was giving me a lot of very “loud” input, and I didn’t have any way of determining which signals might be okay to “tune out.”

There’s a big difference between trying to ignore pain that you think could be a sign of something dangerous happening in your body, and deciding in a calm, rational manner that you are pretty sure you know what’s causing the pain, and that it is not a sign of immediate danger.

Pain is there to protect you and get you to change your course of action when your nervous system thinks you might be in trouble.  In that case, trying to push through the pain and going about your business as usual will only make the pain worse.

But pausing and actually focusing on the pain, deciding you have a reasonable guess as to what’s causing it, and what to do to make it better, can make the pain go quiet.  Or, at least, quieter.  But you have to really believe that you are safe, for this to work.  You can’t think there might be some hidden cause your doctors have missed, that part of your body might be falling apart.

And it’s ok if that’s what you do think.  It is certainly a valid position to be in.  Sometimes there is no simple answer.  I am not telling you you should be able to use the thought process I’m describing here all the time, or implying that there’s something “wrong” with you if you can’t talk yourself out of being scared.  That is the exact opposite of what I’m saying.

I’m just telling you that, the more you know about the body in an objective sense, the easier it will be for you to make sense out of it when the body gives you subjective input.   In my own life, the more I learned about my own body, the less scary pain became to me, which in turn meant there were fewer alarm bells going off.

It isn’t the answer to everything, but learning about these subjects might be the answer to some things.

How a physical therapist helped me through my lowest point, Part 5

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**If you are new to my blog and would like to start at the beginning of this series, click here.**

In some ways, the “cure” wasn’t a magic bullet.  I still do have some pain, and in some ways my life hasn’t really changed.

But in other ways, it was like magic.  Finally, I had an answer for my pain—a real answer.

For so long, I’d been told by various doctors and physical therapists that the answer had something to do with my mental health.  That I was depressed, or anxious, or afraid to move.  That “something bad had happened to me a really long time ago,” and my body was using pain to express my unconscious thoughts about it.

Perhaps there was a grain of truth in some of those things. I hadn’t exactly had a happy adolescence, and I was deeply afraid of the kind of injuries that had forced me to stop running.   I didn’t necessarily identify with the person in the picture they were painting—I didn’t consider myself to be particularly depressed, or troubled.  But these issues loomed large in my past, so it wasn’t too much of a stretch to imagine that maybe they were still affecting me more than I consciously realized.

I had wasted years, since the first person told me at nineteen that he didn’t think there was a concrete medical reason for my pain, wondering if psychological issues were to blame.  I was never completely on board with this theory, but I also didn’t have a better explanation.

For years, every health professional I saw would eventually tell me he or she didn’t understand why I was in so much pain.  “You have some issues with muscle tightness and posture” they would tell me.  “It’s possible you still have scar tissue left over from your surgery.  But I see other patients with these issues, and you are in more pain than all of them.”

Then each of them would proceed to give me some kind of advice.  Most of them were kind, and very well-meaning.  “I think maybe you should talk to someone about this.  I’m not really qualified.  Maybe you should see someone who has been trained how to help people with depression, like a psychologist.”

I called this conversation “The Talk.”  Every time I saw a new doctor or physical therapist, I knew it would come up eventually.

Sometimes I would be upfront about it at the first appointment: “I’ve been told there might be psychological reasons for why I’m in so much pain.” Other times, I would experiment by not saying anything, seeing how long it took for the person to reach this conclusion on his or her own.  Sooner or later, almost everyone did.

I was in college for most of these years, and as a result, I had access to hundreds of well-respected academic databases requiring a paid subscription.

I spent hours pouring over the literature on chronic pain and depression; anxiety and depression; anxiety and chronic pain. Fibromyalgia and chronic pain.  Somatization disorder.  Conversion disorder.  Which therapeutic interventions had been shown to help.

All of it left me feeling like shit.

I just didn’t identify with the kinds of mental health issues these articles would discuss.   In a way, maybe I would have felt more optimistic reading these articles if I actually considered depression to be one of my cardinal issues.

Now, let me be clear: there is nothing wrong with being depressed, or having any other mental health issues.  I have several close friends with mental health issues, who rely on psychiatric medication to live their lives.  There is nothing wrong with that.  There is no shame in it.  Mine is not the story of someone who really is depressed, but just doesn’t want to admit it.

My problem wasn’t depression, it was pain.  Perhaps I would have felt more optimistic reading these articles if I actually felt I had clear-cut case of depression, which might improve with medication and therapy.

I had met with therapists from time to time, over the years.  The medical professionals I would see kept sending me to various people, and, agreeable young woman that I was, I would always agree to go and meet the next person.

But we never got anywhere.  Sometimes the therapist and I would agree that I might have a mild case of depression, but we never had the kind of huge psychological “breakthrough” that the doctor or physical therapist who had sent me there had hoped I would have.   Often times in therapy, the conversation would turn back to pain, and the therapist’s own experience with back or neck pain.   In the end, the therapist would usually just refer me back to physical therapy.

Over the years, whenever I wasn’t too occupied with coursework, I would think about depression and anxiety.  I wondered if it was possible that I was more troubled than I actually felt.

In retrospect, this was a completely pointless use of time, and of course it made me feel worse.  How can it be a good thing to insist to someone who doesn’t feel depressed that she spend time talking to other people about whether or not she might be depressed?  Why dwell on hypothetical negative emotions when you don’t have to?

But there was really no talking to some of these doctors.  Even the most sympathetic could not be swayed.  It was practically at the level of religious belief for some of them: if there is no concrete medical reason for a patient’s pain, then she must have mental health issues.  There was just no way around it.

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That is why the Neil Pearson lectures blew my mind the first time I watched them.   It made so much sense right away—how could anyone have a discussion about pain without discussing the functions of the nervous system itself?  All these doctors I had seen had focused only one aspect of the nervous system: the neurotransmitters of the brain.

But there were other aspects of the nervous system that were worth discussing.    The peripheral nerves, the things that sense mechanical damage, temperature, and chemical signals.  The dorsal horn of the spinal cord, where sensory information enters and travels up to the brain.  The relationship between the brain and the spinal cord, and how, somewhere along the way, your body can decide whether it needs to know more about what’s happening in your body, or whether it’s safe to tune those signals out.

Nowhere in the lectures did Neil bring up the subject of depression.  Not, I am sure, because he had never learned anything about the relationship between depression and chronic pain.  But because there was a better explanation out there, one that did not require a diagnosis of ill mental health.

What had happened to me wasn’t some freak occurrence that had happened only to me, as a result of some psychological trauma I couldn’t even remember.  It was, instead, the result of normal processes of the nervous system being altered by physical trauma, which of course I could remember, and which made sense to me.

How was it possible that none of the doctors or physical therapists I had seen before had known this information?  I wish I knew.  I don’t really have a good explanation, except for that all of the decent research on pain science is very recent, whereas psychologists have been studying depression and chronic pain for over a century.   Some of the theories people were using to diagnose me, I realized, hadn’t changed very much since the days of Sigmund Freud.  It seemed that many of the research studies on depression and chronic pain had been based off of some of these same assumptions.

I am really hopeful that in ten to twenty years, the “conventional wisdom” about the causes of chronic pain will be a bit more modern.  I really hope that, someday, the kinds of things I learned in physical therapy will be taught, not as optional continuing education courses, but as part of the required curriculum in medical, physical therapy, and occupational therapy schools.

To be continued in Part 6!

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Top Photograph: Don’t worry, I don’t understand everything that’s going in this photograph either.  But it seems a hell of a lot more scientific than simply making the assumption that a patient is depressed.  Thanks go to Open Michigan.

Second Photograph: I love when I randomly find awesome things like this on Flickr.  We should all trust in our nervous systems. Thanks go to Cliph for the image.

How a physical therapist helped me through my lowest point: Part Four

This is the fourth part in a series about an amazing new approach to physical therapy for chronic pain patients.  To start from the beginning, check out Part One, Two, and Three.

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For the first few visits, all Tim and I did was talk.  He didn’t have me in the gym doing exercises like all the other patients I walked by on the way in.  Instead, we sat in a quiet area and talked about what I had learned from Neil Pearson’s lectures.

What I learned is that pain is so much more complicated than we think.  When I first learned about the nervous system in high school biology, I was taught that nerve impulses travel through the spinal cord to the brain, where they are interpreted.

simple nervous system

This is a very simple model, and on a basic level it’s true.  That is how nerve impulses get to the brain.  But when it comes to the experience of pain, there are many additional factors.

Normally we think about the nervous system as a one way street, where signals are only travelling to the brain. But what I learned from Tim is that the experience of pain is a lot more complicated.  Our brains are constantly evaluating input from our nervous system, trying to sort out which signals are important for us to know about, and which aren’t.

Our brains are filtering our experiences all the time, determining what is and what isn’t important for us to know about.  After all, it wouldn’t make sense for us to be aware, on a conscious level, of every little thing that’s going on in our bodies.  We don’t need to feel, at all times, the sensation of clothing on our backs.  We don’t need to wake up out of a deep sleep just because there is a blanket touching our legs.  Our brains filter out information all the time, so that we can focus on more important things.

On the other side of this equation, the brain can actually “turn up the signal” on something it thinks we need to know about.  If a part of your body hurts and you try to ignore the pain and go about business as usual, your brain will make that pain louder.  It isn’t doing that to be annoying; it’s trying to protect you.

Lorimer Moseley tells a revealing story about the time he was walking in a nature preserve when a stick brushed against his ankle.  He had once been bitten by a poisonous snake in that same nature preserve, also on his ankle.  He freaked out and fell to the ground, writhing in excruciating pain.  He told his friends to call for help, thinking he needed to get to a hospital as soon as possible.

A few moments later he looked at his ankle and realized there were no bite marks.  There was, instead, a stick lying on the ground next to him with a sharp point.  He was then faced with the awkward task of telling his friends he was wrong, that there was no snake, that he’d freaked out over nothing.

This is how the nervous system works.  It is not meant to be “accurate.”  It is meant to protect us.

When Moseley’s nervous system felt the stick scrape his skin, it knew that the last time it felt those sensations, there had been great danger.  It also knew that not only was he outside, but he was walking in the exact same nature preserve where that same danger lurked.  His nervous system decided to tell him about the dangerous thing that had just happened to his ankle, and it told him about it loudly.  This is how the nervous system works; it decides how much danger we are in based not only on physical sensations but also on context.

Normally when we notice these little idiosyncracies of the nervous system, we are embarrassed.   These little errors in judgment can make it seem like we’re crazy, or overly anxious or neurotic.  But this is how the nervous system works.  It is not meant to be “accurate,” it is meant to protect us.   Even when our nervous system doesn’t have the whole story, it fills in blanks as much as possible, taking our fears and beliefs about the situation into account.

In people with chronic pain, the body’s protective response has gone haywire.  It’s as though the nervous system’s threshold for action has been lowered, and things that didn’t seem dangerous before now seem very dangerous.

It’s like we’re Lorimer Moseley walking through the nature preserve, all the time.  The difference is that Moseley’s case was a singular event based on coincidence: the stick brushed up against him in the same place that the snake had bit him, and he was walking in the exact same park where he had encountered the snake before.  While Moseley’s experience had a concrete end, every day chronic pain patients encounter “sticks” that our bodies interpret as “snake bites.”

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The good news is that, because the nervous system takes our conscious beliefs about pain into account when making judgments, we can actually affect how it reacts to various stimuli.  (I want to be very clear here: we do not cause chronic pain with our thoughts and beliefs.  This is an oversimplification, and it’s also insulting).  But the nervous system does pay attention to context when deciding how dangerous something is.

In his lectures, Neil Pearson says that when your pain starts to get worse, you should ask yourself “Is this really dangerous?”  An increase in pain is a sign that your nervous system has decided whatever you’re doing is dangerous.  But is that really the case?  If you’ve been living with pain for a long time, it might not be.

This is where your conscious thoughts and beliefs can play a role in breaking the cycle of pain.

I had lived with pain for so long that my view of what my body could and couldn’t do had gotten very warped.  I felt pain every time I tried to walk, or lift something, or go up and down stairs.  I thought my body was weak, that there was something fundamentally wrong with it, and every time I pushed myself it seemed to get worse.

Tim helped me to recognize that the pain I felt was not necessarily an accurate barometer for what was wrong in my body.  The reason I had a setback every time I exerted myself, he said, had more to do with my nervous system freaking out than the fact that I had actually pushed my healthy twenty-five year-old body to its limits.  When my body began to hurt, I was to say to myself, “There’s my nervous system again.  Freaking out.  But that doesn’t mean anything is wrong in my body.”

Tim and I talked a lot about how the body works, and how I wasn’t going to hurt my back, or my legs, or my ankle just by doing basic things.  Because one of my major complaints was back pain, we talked about the anatomy of the back, and how my MRI showed I didn’t have any serious pathology.  Tim promised me that my body was so much more capable than I thought it was, and that once I could help my nervous system calm down a little bit, I would see that.

We also talked about what kinds of things would produce pain in a person whose nervous system wasn’t freaking out.  It honestly really helped me to have a trained physical therapist to bounce ideas off of.  I trusted Tim.  If he told me the pain I felt was likely coming from my freaking-out nervous system, rather than any physical damage, I believed him.

We talked about my leg surgery several years before, and how I was afraid my compartment syndrome was going to come back if I pushed my legs too much.  We sat down and had a rational discussion about this; how unlikely it was, but what the worst case scenario really would be if it came back.  This helped to reduce some of my fear, and give back a sense of control.

We also talked about my ankle, which I had sprained a few months earlier.  It still hurt a lot of the time, and I had a lot of trouble walking and driving.  Tim explained that I wasn’t going to re-sprain my ankle just by performing normal activities.  Since it had been a few months, he said, the majority of the healing had already occurred.  As long as I kept my ankle within the normal range of motion, I wouldn’t be doing anything to make the sprain worse.

This actually made a striking difference in the amount of pain I felt in my ankle.   My nervous system had been interpreting the sensations in my ankle as very dangerous, and as a result it was very painful.  But once my brain understood that my ankle wasn’t in any real danger anymore, my nervous system no longer saw the need to tell me about it all the time. Over the course of the next few weeks, the pain in my ankle gradually melted away.

It’s almost embarrassing to admit something like this– that my ankle, which had been bothering me for months, stopped hurting as soon as someone explained to me that it wasn’t really dangerous.  But it shouldn’t be embarrassing.  This is how our nervous systems work: they take into account both physical signals as well as our mental interpretation of events.

If you’ve undergone the process of central sensitization, your nerves, spinal cord, and brain have changed in ways that cause you to be more sensitive to pain.  Scientists don’t yet know whether or not these physical changes are actually reversible.  But the good news is that whether or not you can undo the effects of central sensitization, you can still break the cycle of pain by changing how you react to pain on a conscious level.

Continued in Part 5.

**The top picture was taken in the Australian Outback, which is where many of Lorimer Moseley’s stories take place.  Published by Mark Veerhart under a Creative Commons license.**

**Mulberry sticks picture courtesy of JodiGreen**