Thursday, January 31, 2008

Feedback All Over Again

Response to: Getting a handle on back pain

Hi Diane!

I think this passage from the article is the most important:

From the perspective of the brain, there are two distinct types of pain. The first type of pain is sensory. When we stub our toe, pain receptors in the foot instantly react to the injury, and send an angry message to the somatosensory cortex, the part of the brain that deals with the body. This is the type of acute pain that doctors are trained to treat. The hurt has a clear bodily cause: if you inject an anesthetic (like novocaine) into the stubbed toe, the pain will quickly disappear.

The second pain pathway is a much more recent scientific discovery. It runs parallel to the sensory pathway, but isn't necessarily rooted in signals from the body. The breakthrough came when neurologists discovered a group of people who, after a brain injury, were no longer bothered by pain. They still felt the pain, and could accurately describe its location and intensity, but didn't seem to mind it at all. The agony wasn't agonizing.

This strange condition - it's known as pain asymbolia - results from damage to a specific subset of brain areas, like the amygdala, insula and anterior cingulate cortex, that are involved in the processing of emotions. As a result, these people are missing the negative feelings that normally accompany our painful sensations. Their muted response to bodily injury demonstrates that it is our feelings about pain - and not the pain sensation itself - that make the experience of pain so awful. Take away the emotion and a stubbed toe isn't so bad.

Chronic pain is the opposite of pain asymbolia. It's what happens when our brain can't stop generating the negative emotions associated with painful sensations. These emotions can persist even in the absence of a painful stimulus, so that we feel an injury that isn't there. It's like having a permanently stubbed toe.

Doctors have traditionally focused on the bodily aspects of chronic pain. They assume that a healed body is a painless body. If a patient has chronic back pain, for example, then he is typically prescribed painkillers and surgery, so that the pain signals coming from his spinal nerves are stopped. But the dual pathways of pain mean that this approach only treats half of the pain equation. Unless you find a way to treat the emotional pathway, then the chronic pain will continue.

It might not be the perfect description of chronic pain - but it is very helpful to explain the connection between emotional states and pain - and why there is no "imaginary" pain.
All pain is real since it is always constructed in the brain.

Using fMRI to provide visual feedback is overkill. It's nice to see that feedback therapy works regardless of which type of feedback you give to the brain - put in the case of chronic (low back pain) it's much easier to do with tactile stimulation.

What I don't like about this type of therapy is it's reliance on high-tech.
After all: what good is this type of therapy if only a very small percentage of people can benefit from it?

If you want high-tech - think of our brains. Organic computers that are able to change, to evolve, to learn. We have to realize that our brains are the most high-tech "gadgets" out there so to speak - and use them accordingly.

I completely agree with Ian that we should start focusing inwards more. It's cheaper, more efficient in the long run (because if you work on yourself you learn for life) and puts responsibility and control back into the hands of the patient.


Anonymous said...

Hi Folks,

I haven't chimed in here yet so I thought I'd take this opportunity to post. I'd like to coin a new diagnosis for those not doing the focusing inward bit: "Introspection deficiency disorder". You heard it on neurotonics first.

Great blog!


dermoneuromodulator "neuroplastician" said...

"Introspection deficiency disorder" is brilliant - thanks for that Jon, it made me smile. IDD would also become known as "Jon's Syndrome", you realize... not that you have it, but that you came up with the label, so your name would forever be linked to it and the constellation of symptoms and signs it denotes, for better or worse.

Thanks for appreciating Neurotonics.

Anonymous said...

I don't have IDD but I do have "order deficiency disorder", which is odd.