The pain drawing has to be one of the more ubiquitous assessment tools around. There are many versions of outlines of naked bodies on which a person can scribble, colour, and write to indicate to treatment providers exactly where they feel their pain, and to a certain extent, some of the sensory features of that pain. But – how many of us use that drawing for anything other than ‘Oh so that’s where you feel it?’
Schott, in this truly interesting paper, discusses pain maps – not a term I’d come across before – and traces the history of pain maps as well as discussing some of the problems with it – and concludes that pain maps can contribute something quite unique to our understanding of the person’s experience, but at the same time, acknowledges that interpreting them continues to be problematic. Given that clinicians so often use pain maps, it’s timely to start doing some work on improving our understanding of both their positive qualities and their limitations.
So, what exactly is a pain map? First and foremost, it’s marks made, usually on a mannikin or template of a body, of an individual’s own experience. In my view, this makes it a pain behaviour – a vehicle for communicating to us something that the person wants us to know about. All communication requires encoding by the person and decoding by the receiver. In this case, the person completing a drawing needs good spatial awareness, body awareness, coordination and eyesight to be able to communicate – and these aspects are strongly influenced by our neural networks. To be able to translate where ‘I’ feel my pain on my body onto a mannikin means I need to be able to imagine its location on an object that is not the same shape or size as my body. What’s worse – the mannikin is a mirror image of the person’s body, so laterality and the ability to manipulate images in the imaginations is needed. A recent paper by Lorimer Moseley (2008) used maps to show areas where the person expereinced pain, and overlaid upon this, areas where the person was unable to delineate part of their trunk.
Pain behaviours are also effective indicators to others of people’s distress. There is possibly something ‘diagnostic’ about a pain map where the whole body is covered in marks, with lots of additional comments written all around the body – to me it can mean high levels of distress, lots of awareness of the body, and an intention to communicate to me just how ‘bad’ the pain is. It’s worth me taking my time to explore these concerns with the person, so I can understand their thoughts and beliefs about their pain. What I can’t do is decide that, just from a pain map, the person is ‘malingering’ or ‘exaggerating’ – for reasons I’ve discussed in the past. And a recent review, cited by Schott is that pain maps are not useful for indicating psychopathology or as psychological screening tools (Carnes, et al., 2006).
Pain maps are useful for recording an individual’s pain experience at a particular time – as Schott indicates, they can be useful in a sub-acute setting where pain distribution doesn’t change rapidly – and because they can be retained, and they’re pretty inexpensive to produce, they can provide a long-term record of pain distribution. They’re also helpful for people who may not have words to express their pain – although the instructions on how to complete the map, and the physical coordination needed to manipulate pens as well as the ability to visualise as I’ve discussed above, may make this a more difficult task than we sometimes realise.
Many years ago I recall clinicians referring to pain maps and attempting to use them to interpret whether a person’s pain was ‘organic’ or ‘functional’. Thankfully I haven’t heard this for a while – partly because I don’t think those terms are helpful anyway, but also because people’s maps reflect their own experience, and especially with what we know about central sensitisation, it’s likely that an individual’s pain will be distributed in patterns that don’t necessarily represent ‘anatomical’ patterns. That’s certainly the case in something like fibromyalgia where the pain is likely to be located all over the body! Schott refers to a paper by Rankine et al., suggesting that there is limited value in trying to use a pain map to decide on the underlying cause of the pain, especially when good examination and investigations are carried out. (Rankine, et al., 1998).
So, what can a pain map do for us as clinicians? I think one of the main things it can offer is a ‘talking point’. It gives me as a clinician and the person I’m working with a common ‘language’ about which to discuss their experience. It’s a help record, over time, for people with chronic pain who might return to a clinic after a break of some years – has their map changed?
The work that Moseley and colleagues have carried out with mapping perceptual changes in chronic pain has great appeal – and I hope work in this area will provide more information about how people perceive their body when they have pain and so give us more information on perception and cortical changes.
Schott, G. (2010). The cartography of pain: The evolving contribution of pain maps European Journal of Pain, 14 (8), 784-791 DOI: 10.1016/j.ejpain.2009.12.005
Carnes D, Ashby D, Underwood M. A systematic review of pain drawing literature: should pain drawings be used for psychological screening? Clin J Pain 2006;22:449–57.
Moseley GL. I can’t find it! Distorted body image and tactile dysfunction in patients with chronic back pain. Pain 2008;140:239–43.
Rankine JJ, Fortune DG, Hutchinson CE, Hughes DG, Main CJ. Pain drawings in the assessment of nerve root compression: a comparative study with lumbar spine magnetic resonance imaging. Spine 1998;23:1668–76