ReExplaining Pain – Moseley’s evidence - phantom limb pain

Phantom limb pain is my pet hate because it’s always trotted out as “proof” that pain is purely in the brain, not the body.

Moseley loves this one. It’s one of his TWO pieces of evidence for Explain Pain, and I’ll deal with the other one in another article (very soon).

Moseley says that because phantom limb pain exists, that proves he’s right and pain is purely an output of the brain. Because pain can’t be related to tissue damage/pathology if there is no limb there to hurt!

And, superficially, he has a point. But take a moment to think about it, and his idea quickly falls apart. In my opinion, anyway.

In fact, I believe his ‘evidence’ actually proves the opposite.

My thoughts:

Phantom limb pain happens when someone feels pain in a limb that’s been amputated. The limb is no longer there, but the pain is real. And sometimes this pain is very severe, unbearable. And very hard to treat. Just because the limb is gone, does not mean the pain is imaginary! Or unlinked to physical damage. Quite the opposite, in my opinion.

The person’s nerves have been severed. That is a massive injury, very real and serious pathology. The nervous system is no longer intact. The pain is generated because of that injury. Yes, the brain is involved (it always is), but it’s responding to a damaged, dysfunctional input system. Severed nerves, neuromas, spinal cord reorganization, all pathological, all capable of triggering pain.

But what really drives me crazy, and always has, is the simple truth that you CANNOT compare the behavior of a damaged nervous system to a healthy one. You cannot expect a damaged nerve (severed!) to behave the same as an intact nerve! Yet Moseley does this. Apples to oranges, which is a common tactic of his.

Phantom limb pain is not an example of the brain randomly creating pain. It’s the brain responding, in a dysfunctional way maybe, to trauma and injury. Not “pain without pathology.” That’s pain because of pathology. Losing a limb is serious trauma. Serious pathology. Phantom limb pain is due to pathology. It is NOT just an output of the brain, that can be simply and easily ‘retrained’ with education.

So no, phantom limb pain doesn’t prove that pain is just an output of the brain. It proves that when the body is seriously injured, the nervous system can go haywire. That’s a world apart from saying pain “is in the brain” in people with no detectable pathology. And is sure as heck does not prove it, in my view.

And just to drive the last nail into the coffin, in my opinion anyway, know this: people with congenital missing limbs do NOT experience phantom limb pain.

They experience sensations, its thought because the body has an internal ‘map’ of its body parts (the homunculus) that is intact despite having been born without a limb. So they feel sensations, but NOT pain, not severe pain the way those who have had a limb amputated feel.

This proves that the pain is due to damaged/severed nerves. Pathology. Clearly and comprehensively showing that the pain is due to nerve damage (it’s been severed!) NOT that ‘pain is in the brain’.

Moseley hates any mention of this because, yet again, his theories are debunked and proven to be… dubious at best. Of course, very few question him, cos he’s such a good bloke. But. Bottom line: phantom limb pain does not prove pain is in the brain, it proves the opposite. It proves definitively that pain is due to pathology, to physical damage.

In my opinion, anyway.