Central Sensitization Syndrome (1)

Mayo Clinic's Christopher Sletten, Ph.D., ABPP discussing Central Sensitization Syndrome, which is the prevailing theory of the cause of chronic pain & other chronic symptoms. A patient and/or provider understanding of this process can lead to seeking appropriate treatments including the Pain Rehab Center (PRC) at Mayo Clinic's Florida campus. Learn more about the PRC program in Florida: mayocl.in/prcfl.

Mayo Clinic Florida
Comprehensive Pain Rehabilitation Center (PRC)

Hello, my name is doctor Christopher Sletten. I am the clinical director of the Pain Rehabilitation Center at the Mayo Clinic in Jacksonville, Florida. I’d like to present in the next several minutes an overview of how we view chronic pain and chronic symptoms to hopefully give you a better idea of some opportunities for treatment and managing these difficult situations.
Every year thousands of patients come to the Mayo Clinic seeking an answer to their problems. And many of those patients come and are somewhat disappointed, because they’re told they have a chronic problem, a chronic condition, symptoms that aren’t necessarily easily managed. And some even are quite frustrated, because the Mayo Clinic was unable to solve their problem.

One of the reasons for this is a concept that’s rather new in the medical literature, called central sensitization.

I’m going to describe for you over the next several minutes how this process works, and the consequences for you as a patient (or if you’re viewing this as a family member your loved one’s difficulty) with symptoms that can continue to grow and become more and more problematic.


Central sensitization involves two steps within the nervous system. The first involves peripheral input. The second involves the central nervous system itself.

In the periphery all of us have tiny sensor cells in every square inch of our body – except for our hair and fingernails. That’s why you can usually clip your nails and get a haircut without too much pain. In those sensors all sorts of physical sensations are fed to the brain.


So, we have sensors in our skin, gut, muscles, joints, bones, we have it in our balance system, our nerves, our vascular system, we have it with our vision system, hearing, taste, and smell.

In a normal circumstance, these sensors are just monitoring our environment, sending a signal to the brain to be dealt with.
So, if you’re too hot, you may go to a place to cool off. If you’re thirsty, you might drink some water. If you have to go to the bathroom, you go to the bathroom.

And so the signal is not abnormal in and of itself, but if there is some circumstance, or set of circumstances, that can trigger an escalation in these sensations, then these sensors in all these different parts of the body can be upregulated.

Once they’re upregulated, they permanently strengthen their signal. That is: sounds can seem louder, lights can seem brighter, movement can hurt worse, digestive systems can seem more problematic. And once that upregulation happens in the periphery, we now start to develop a set of symptoms that become more bothersome and also more difficult to treat.

And many people will ask: “Well, what causes this?” And to date we don’t have one set answer, but I’ll give you some examples. This may be started by an injury, may be started by an illness, a disease, may be triggered by surgery, some repetitive injuries, might be hereditay, we don’t know.

But at the point where we can begin to help, trying to sort out the causes is no longer very necessary. You’ve had the examinations, you’ve had the tests, the evaluations done by very careful and thorough doctors. And if they don’t find anything right now that’s an emergency to treat, we need to sort of look beyond the cause and look over to the process that’s occured as a result of the cause.

Once we get this upregulation – so, I‘m going to write here “upregulated” peripheral input. Once it’s upregulated, there is now a stronger and stronger signal sent to the brain. And one part of the brain that begins to react, is called the somatosensory cortex. This gets sensitized – that’s where we get the word sensitization.

So, the somatosensory cortex is where all of our sensations go to our brain to be analysed. And again, in a normal situation we might acknowledge a sensation, deal with it and move on.

However, if these [sensations ] are upregulated, that is they’re stronger, they’re more uncomfortable, they’re more noticeable. Now the sensations in the brain become noticeable to the person, more uncomfortable.
And the somatosensory cortex is organised by body part. So, if a body part starts to bother a person, they can develop all sorts of sensations around that body part. Now it hurts to be touched on the arm that was injured at one time. It hurts to move that limb or internally digestive processes may be more bothersome. And you can have increased sensation all the way throughout the body.


Without getting to too much more detail this afternoon, this process, this upregulation leads to a whole range of symptoms that become worse over time: pain, fatigue, feeling dizzy, nausea, sensitivity to temperature, touch, taste, sounds, smells, even barometric pressure can bother people sometimes.

So, as is this sensation increases as the sensitivity increases, we see patients more and more desperate for relief, more and more confused about what’s going on.

And as this process progresses, this leads patients to go into the “ologists”, all of the specialists.
And often patients don’t go to just one set of specialists, they go to several. This is what we frequently see at the Mayo Clinic. Many of our patients have been to several other specialty clinics, have seen many other specialists for their problems, and the answers are not clear.

So, the proliferation of symptoms and sensations, along with the increased sensitization, along with the increased input from the body, leads to increased distress and difficulty.

I’m going to pause for a second and I want you to think from what I’ve drawn so far on the board: how much of this is psychological? The answer is none.
This process is a sensory physical process that works itself into higher, higher levels of stimulus and distress over time. There’s nothing psychological about this process. Patients that have central sensitization did not bring this upon themselves. There’s nothing necessarily mentally impaired about persons with central sensitization.
And this is an important point to understand, because so many patients, and their families, feel as if nobody believes them.

One of the other difficulties of central sensitization is it’s often invisible. We can’t see your senses, and so, when you have these increased sensations, it’s also hard to get them measured by a medical professional.

Now, let me go above the board here for a second, and I want to explain that the way we look at the last step in the process is that there are four, what I call, reactive and maintaining factors.

Reactive in the sense that these four areas become a reaction to the increased sensations, whether it be pain, or fatigue, or dizziness, or whatever, but they also begin then to feedback in and make the problem worse. So, the four situations are:

  1. Chemical
  2. Behavioural
  3. Emotional
  4. Psysical

Let me just briefly take these in term:


Many, many persons that we see with central sensitization have been given medicines to control their symptoms. And unfortunately the more medicines a person in given, the more confused their brain can get, the more confused the chemistry can get. We call it polypharmacy. And so, when patients are given pain medicins, and sleeping pills, and nerve pills, and antidepressants, and membrane stabilizers, and GI medicines. It just gets to be more and more confusing for the brain and the body, and it actually can make the problem worse. So, it’s very understandable to see how a doctor might prescribe you some medicines at the beginning, when they’re not sure what’s wrong. But over time, as this process goes on and on, those medicines can actually be counterproductive and hurt your functioning.


There is a behavioural element as a reaction to sensitization and those symptoms. If it hurts, often people will stop doing things. Pain behaviours, things that a person says, does or thinks, that reminds themselves or others that they’re in pain, can get worse. Every behavioural response we have to these unpleasant sensations can inadvertently make the situation worse.
Another behavioural pattern we see frequently: pushing and crashing. So many of the patients we work with, have identified that when they feel better they do too many activities, they stir everything up, and then when they feel worse, they rest too much. That’s going to lead to physical deconditioning. That’s also going to directly stimulate more sensation.


It’s very normal to have emotional distress when you have symptoms that are unexplained, hard to control and are interfering with your life. So, we do see some depressive symptoms, anxiety symptoms, stress symptoms that do need to be dealt with. Because every time the brain is under emotional distress, it’s going to experience more sensory or physical distress. The emotions are a response, not a cause, of this problem.

Lastly, physically

Many, many of our patients are physically deconditioned, have stopped doing things, may have had their bodies altered by treatments and surgeries. And they need assistance in managing their physical functioning, as much as the emotional and chemical issues.

So, when you look at the way we manage this, we help people in a programme that is called the Pain Rehabilitation Programme. The Pain Rehabilitation Programme is a three week programme. It’s every day, Monday through Friday, 8:00 to 4:30 (pm), and every single day we deal with all of these issues. We help patients come off strong medications, we deal with their emotional distress, we help them get physically stronger, and we give them a game plan to move on with their lives.

By the end of our programme on average our patients are experiencing 40% less symptoms, 50% more physical functioning, 60% more daily activities. And once our patients learn this process, it goes on into the future. As long as they apply these principles, they’re going to continue to do better, and better, and better.

Because in closing the way we look at how we impact this system, we can’t directly shut this [the sensitized somatosensory cortex] off. There’s no medical or technical way of doing this. But if we cut off the influence of these [reactive and maintaining] factors, then the sensitization in the activity of that part of the brain begins to go down. Very much like cutting the fuel out of a forest fire, so that the flames begin to go down and down. That’s the way we can manage a situation.

So, please consider this model if you’re dealing with difficult to manage symptoms, you’ve been told there’s nothing more that can be done, we’d be happy to assist you and this is a very effective treatment modality for persons with chronic symptoms.

Thank you.


Sourcce: www.youtube.com/watch?v=8defN4iIbho (5th August 2015).

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