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Can psychological management of fibromyalgia affect pain?


ResearchBlogging.org
When I’m working with someone who has chronic pain, from the outset I’m pretty straight-up that the treatments I offer don’t directly affect pain intensity.  It’s not my focus, and very often after the first session, I don’t even discuss pain – I’m more interested in what the person is doing! And for this focus, I sometimes get some reasonably snippy comments, none more so than a doctor (who shall remain nameless) who said to some of my students that psychological and functional approaches to pain management are, in effect, useless because they ‘can’t directly address the pain’.

Well, I beg to differ, kind sir. While pain intensity isn’t the focus of treatment, it very often is affected by the treatments offered using a cognitive behavioural approach – and here’s a lovely meta-analysis by Glombiewski and colleagues demonstrating just this.

Fibromyalgia is, arguably, the prototypical ‘central sensitivity’ pain problem.  Although the mechanisms of fibromyalgia are still somewhat unclear, it’s becoming more evident that it’s the descending inhibitory pathways that are affected in this disorder.  What this means is that more information than in ‘normal’ people reaches the higher centres of the central nervous system, resulting in the brain identifying this information as ‘dangerous’ and therefore, more painful, than for other people.  I have fibromyalgia, and for me it means aching, burning, fatiguing pain that travels around my body, as well as fatigue that can make it more difficult to cope with the pain I feel.  I reframe this as being ‘more sensitive’, so I am really a ‘sensitive soul’!

Back to a meta-analysis.  Meta-analytic studies are a great thing – they summarise and mathematically establish, across multiple studies, the effects of treatments.  What this means is that a great many studies are collected together, and the findings summarised so that it’s possible to find out the overall effectiveness of a particular treatment – provided that the studies use pretty much the same inclusion criteria, outcome measures and reporting methods.  In this case, 1530 studies met the initial inclusion criteria – but only 24 studies actually made it through to the final analysis!  One of the arguments against meta-analytic studies is that many pieces of research don’t get included because of various shortcomings in, perhaps, outcome measure methodology, treatment approach, or lack of randomisation etc.

Nevertheless, 24 studies were able to be included, and ranged across cognitive behavioural approaches (in this study, to be included as a CBT approach, the study needed to have cognitive, operant and/or respondent techniques in combination), biofeedback/relaxation training, mindfulness, educational and behavioural approaches.

What the researchers found was that a cognitive behavioural approach provided small but robust improvements in pain intensity reduction, sleep duration and low mood, and that these improvements were evident over both short and longer term.

A further finding was that there was a ‘dose-response’ effect – longer or more intense programmes provided better outcomes, while briefer input resulted in lower effects.

Now a question here  – how can a hands-off treatment change pain intensity?  This is the question that my good doctor friend doesn’t understand.  If your view of pain is that nociception is all there is to pain perception, then I guess it does make it difficult to understand how pain can be influenced by a treatment that doesn’t target the nociceptors.  (A brief refresher on nociception – this is the transmission of information from the periphery of the body to various parts of the central nervous system via a sensory receptor that responds to potentially damaging stimuli.)

I think my colleague’s misconception is that he believes that there is a dedicated system that sends ‘pain signals’ to a passively receptive brain, or more specifically, the sensory and motor cortex of the brain, to be ‘perceived’ – and that the only way to change ‘pain’ is by interrupting these signals.

If only it were so easy!  But this view is a very simplistic one, and our central nervous systems far more complex than this.  My thought is that if our ability to survive depended on a dedicated ‘pain system’ then we’d risk it being knocked out or damaged far too easily, so it’s much more likely that a ‘distributed system’ approach has evolved wherein pain is a product of a neuromatrix that has the job of detecting information about our body that is important (ie salient) and novel (ie new or changing).

I’m not alone in this view either!  A nice paper by Iannetti and Mouraux (2010) details this model of pain, developing the original idea of a multimodal neuromatrix proposed by Melzack and rebutting the concept of a ‘pain matrix’.  Well worth reading if you’re interested in neurobiological theory of pain.

As a result of acknowledging that a neuromatrix exists to process information about the body and environment and to detect important and new information that could be a threat to the individual,it makes sense to me that any effort that alters the threat value of that information about the body state is likely to – reduce distress, improve mood, improve function, reduce disability – and reduce pain intensity and even quality.

Does the converse hold true? If a signal to the brain is disrupted, without altering the threat value of that information, is it likely that the pain will reduce? Well maybe, because at least some of the information isn’t reaching those parts of the brain there to detect important information.  But on the other hand, it may also disrupt the information that the neuromatrix thinks ‘should’ be reaching it, and in so doing, maintain pain – and distress, anxiety, low mood, disability and difficulty doing what the person wants to do.

We can’t do just one thing and hope to influence such a complex phenomenon as pain.  If pain is a biopsychosocial thing, then it probably takes biopsychosocial treatment to change it.  And that, my dear medical pal, is why psychological and functional approaches can influence pain intensity – and much more beside.

Glombiewski, J., Sawyer, A., Gutermann, J., Koenig, K., Rief, W., & Hofmann, S. (2010). Psychological treatments for fibromyalgia: A meta-analysis Pain, 151 (2), 280-295 DOI: 10.1016/j.pain.2010.06.011

Iannetti, G.D., Mouraux, A. (2010).  From the neuromatrix to the pain matrix (and back). Exp. Brain Research, 205, 1-12.

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