Wednesday, March 25, 2015

How your brain can control chronic pain

I am currently entranced by Norman Doidge's new book, "The Brain's Way of Healing", the follow-up to his bestseller "The Brain That Changes Itself". The title sounds somewhat new-agey, but this is definitely hard, cutting-edge science (Canadian-born Doidge is a trained psychiatrist, and a research fellow at Columbia University in New York and at the University of Toronto). It is, however, cutting-edge science presented in clear, everyday English, and explained in a lucid and straightforward manner ideal for ignorant laymen like me, rather in the mold of fellow science writer Oliver Sacks.
The book looks at how the brain's amazing plasticity - one of the breakthrough discoveries of modern science - can be co-opted to ameliorate, and sometimes even cure, some debilitating disorders and conditions, from chronic pain to autism, ADHD, Parkinson's, multiple sclerosis, stroke damage, even some kinds of blindness.
As an example, one chapter of the book looks at chronic pain, and in particular the work of pain specialist Michael Moskowitz, M.D. Here is a little potted summary of that chapter.
Acute pain is a physiological and mental mechanism designed to alert us to bodily damage and injury, and to warn us not to do anything that might make the injury worse. Pain receptors in the body trigger particular areas of the brain that relate to the body region in question, in what is sometime referred to as the "body image" or "virtual body" in the brain. In theory - and sometimes in practice - we can turn off acute pain by just keeping very still, so that the brain does not foresee any likelihood of the injury being aggravated.
Chronic pain, on the other hand, occurs when this pain mechanism becomes corrupted or exaggerated, and the pain receptors and the neurological processes they trigger become over-sensitized. With this kind of "learned pain", the body's pain alarm system becomes stuck in the "on" position. Sometimes the brain begins to enlarge the area where pain is felt, or "referred pain" may be experienced in an entirely separate physical region. Such pain is notoriously difficult to treat.
Moskowitz's happy idea was to try and take back those brain areas that had been taken over by this excessive pain processing, by forcing the patient to counter-stimulate them with some other activity (e.g. visual, auditory, tactile, etc) not related to pain, in a process of "competitive plasticity". He found visual stimulation the easiest sense to co-opt in this regard, and called on patients to visualize images of the brain's pain-processing areas shrinking to zero whenever the chronic pain occurred (other images would serve the same purpose, but this was his first idea). This procedure must be applied consistently and relentlessly whenever the pain appears, so that over time the brain relearns, and the neural networks that were once used to trigger the chronic pain are reconfigured.
Typically, progress is slow and somewhat dispiriting at first, but with dogged and consistent application the theory apparently works, and long-term chronic pain can be entirely eliminated. Furthermore, unlike with the use of pain medications, the change is permanent and relapses tend not to occur.
Perhaps this sounds a bit like hocus pocus, or at least like self-hypnotism or even the placebo effect. But, this is based on up-to-date neurological science and, unlike with the use of placebos and hypnotic suggestion, the results appear to be long-term and possibly permanent. If the patient's initial problem is not resolved, acute pain may reappear (as indeed it should, as part of the body's built-in warning system), but the chronic pain does not. Neither is it a generalized relaxing effect like meditation; Moskowitz's technique targets the chronic pain with laser-like precision.
Fascinating stuff, and I look forward to reading how similar techniques can be used to deal with a variety of other conditions and diseases.

I must confess, after the first few chapters - and particularly after the chapter on Parkinson's disease, which has particular relevance for my wife - I found my enthusiasm for, and attention to, the book beginning to wane, and I found myself skimming and skipping towards the end.
There is certainly much food for thought in the book, but among other things, I found the detailed back-stories (of both patients and medical practitioners) just a bit too long and comprehensive after a while. I understand the need for the back-stories, both to establish baselines for patients' conditions, and also to add a little human interest to what could be a very dry and clinical account. But somehow they seemed to be just a bit too front-and-centre and intrusive after a while.
I also found myself wondering, after reading about one miraculous cure after another, why these techniques were not more widely adopted if they were indeed as effective as they seem to be. Now, of course, that is part of the point of the book, that the medical establishment is overlooking such non-standard approaches to treatment. But I found myself thinking that surely even a staid medical establishment would not ignore such promising and apparently side-effect-free cures if they were truly as miraculous as reported. Would they?

No comments: