In a recent TED talk, an expert in the management of chronic pain in children explains neuropathic pain, a form of chronic pain in which the nervous system itself becomes faulty and creates the experience of intense pain, both the sensation of pain in the brain and the side-effects of injury in the affected (but not actually injured) part of the body.
The analogy that Stanford professor Elliot Krane draws in this short talk is that it’s like stroking your arm with a feather:
But the sensation is as if it’s a blowtorch:
A specialist in working with children who suffer chronic pain, he says (1:55):
Imagine I were to stroke your child’s arm with this feather, and their brain were telling them that they were feeling this hot torch.
Case study
He tells the story of a 16-year old dance student who sprained her wrist, but instead of the wrist recovering in the usual way, chronic pain of this kind crippled her whole arm. After treatment at a specialist pain clinic she recovered completely, and she is now continuing with her dance studies.
The talk briefly describes how this can happen. It’s thought that cells in the spinal cord malfunction and create a feedback loop that generates false pain signals, affecting the brain’s perception of pain and also affecting the arm itself.
Emotion
It struck me while watching the talk that the experience it describes is not a million miles away from the emotional pain that cripples the lives of many people with mental illnesses. There’s an initial event, or maybe a sequence of them, and the pain of that event somehow causes a malfunction — a feedback loop that constantly turns mild everyday sensations into intense pain.
Of course, emotional pain of this kind is unlikely to be caused by a malfunction in the spine.
Treatment
The treatment he describes includes painkillers and local anaesthetics, but its main focus is on (6:30):
…therapy to retrain the nerves in the nervous system to respond normally to the activities and the sensory experiences that are part of everyday life.
In addition:
…we support all of that with [an] intensive psychotherapy programme to address the despondency, despair and depression that always accompanies severe chronic pain.
In broad outline, the treatment is remarkably similar to therapy for emotional pain. The goal in both cases is not to destroy all feeling, but to break the feedback loop and restore normal feeling.
While chronic physical pain requires physiotherapy to retrain the nerves, chronic emotional pain requires psychotherapy to retrain the mind.
Here’s the whole talk:
What I don’t quite understand is how the ‘pain’ is a result of that feedback loop. The person would continuously feel their arm being touched but why does it come with pain?
The animation gave me the impression that faulty glia amplified any signal from the arm, causing it to be interpreted as pain. Perhaps there is normally a negative feedback mechanism that balances the amplification, and when the negative feedback gets broken the system goes into overload, but I am just speculating in saying that.