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!