Pain science is not a thing

Today’s post is occasioned by reading several discussions on various forums where the term “pain science” and various adjectives to describe this kind of practice. For those who don’t want to read the rest of my ramblings: no, it’s not a thing, science is an approach to understanding phenomena, and I would have thought all health professionals would use a science-based approach to treatment.

I went on to Google, as you do, to find out when this term began its rise in popularity. Google wasn’t particularly helpful but did show that it’s been around since 2004 at least, and seems to have been centred around the US, UK and Australia in roughly May 2004. I can’t grab data from earlier than this, sadly, but I think it’s interesting to take a look at the popularity peaks and troughs…

So, what does “pain science” mean to commentators? I haven’t delved in too deeply to the social media use of the term, but given I’m a social animal and have written my blog since 2007 (which is mainly on “pain science”) I’ve encountered it many times. It seems to be related to using a neurobiological explanation for pain as an experience (referring to the phenomenon and the underlying biological processes involved) rather than focusing purely on biomechanics or tissue damage/nociception as the key force. And it does seem to tie in with the emergence of “Explain pain” as one way of helping people reconceptualise their experience as something they can influence rather than something other people need to “fix”.

Commentators who aren’t in love with the “explain pain” thing have said things like “the pain science camp” or as one person put it “There’s your manual PTs, your pain science PTs, and your just load it PTs etc”

I went on to Twitter and the hashtag #painscience was paired with #BPSModel and #PT and #physicaltherapy (or variations), #chronicpain #exercise #lowbackpain – and so on.

So what do I think pain science means if it’s not a neurobiological approach to pain management? Well – pain science is a lot like cardio-respiratory science, and neurological science, and psychological science – it’s about applying a scientific approach to understanding pain. Science has been defined as “the intellectual and practical activity encompassing the systematic study of the structure and behaviour of the physical and natural world through observation and experiment.” In this instance, Google is your friend. So science is about systematically studying phenomena through observation and experimenting. If we apply this to pain – it’s the systematic study of structure and behaviour of the phenomenon we call ‘pain’ through observation and experiment. For what it’s worth, scientific study of pain has been going on since… oh at least Descartes, but probably much earlier given that pain is a ubiquitous and essential part of human experience.

To me, understanding pain involves multiple disciplines: yes to biology, and especially neurobiology because the experience (as we understand it now) involves neurobiological processing. But it’s also about psychology –
the scientific study of the human mind and its functions, especially those affecting behaviour in a given context; sociology – the study of the development, structure, and functioning of human society; the humanities – the study of how people process and document the human experience; politics – the activities associated with the governance of a country or area, especially the debate between parties having power; and Anthropology –  the study of humans and human behavior and societies in the past and present. Social anthropology and cultural anthropology study the norms and values of societies. Linguistic anthropology studies how language affects social life.

So to describe an entire approach to understanding a phenomenon as if it’s a “movement” or “camp” or “dogma” or even “tribe” suggests serious  misunderstanding of both science and of an intervention.

What is “explain pain” then, or pain neurobiology education? – it’s an explanation of some of the biological elements of our nociceptive system as they combine to produce the experience we know as pain. For some people it’s the first time anyone took the trouble to explain why the pain of a papercut feels so bad compared with, for example, the pain of a sprained ankle; and why they still experience pain despite having no “damage” as visible on imaging. It’s an attempt to give people a frame of reference from which to understand their own journey towards recovering from a painful injury/disease/problem. In itself it’s not new: explanations for pain have been used in pain management programmes since the 1970’s (and earlier, if we consider that Fordyce used explanations in his behavioural approaches to pain management), and have routinely drawn on current pain research to help provide explanations that make sense to both the person and the clinician. The distinction between earlier explanations which drew heavily on the gate control theory, and this latest iteration is that the explanations are more complex, pain is considered to be an “output” that emerges from multiple interactions between brain and body, and that’s about it. Oh and it’s been picked up and enthusiastically used by physiotherapists (and other primarily body therapists) around the world.

What’s the evidence for this approach? Well, IMHO it’s not intended to be a stand-alone “treatment” for most people experiencing pain. I see giving an explanation as integral to usual practice, just as we do when we explain why it’s not a good idea to go running on a newly sprained ankle or why we’re suggesting a mindfulness to someone with a panic disorder. So far there have been a lot of studies examining variants of “explaining pain” alone or in combination with a number of other treatments including exercise. A recent systematic review and meta-analsyis of “pain neuroscience education” for chronic low back pain found eight papers (with 615 participants) showing that in the short-term, this kind of education reduces disability (by 2.28 points on the Roland-Morris Disability Questionnaire which is a 24 point scale) in the short-term and a slightly lesser effect in the long-term  (2.18). There were greater effects when this was combined with physiotherapy, though we often don’t know exactly what is included in “physiotherapy”.  There was some evidence that this kind of education helps reduce pain scores (by 1.32) but only in combination with other physiotherapy interventions. The authors pointed out that the strength of evidence for education on pain in the short term was low to moderate, but that it doesn’t have much of an impact on pain-related fear and avoidance, or on pain catastrophising (Wood & Hendrick, in press).

To compare this with another active treatment, exposure therapy for fear of movement/reinjury in chronic low back pain, de Jong, Vlaeyen, Onghena, Goossens, Geilen & Mulder (2005) performed a careful study of six individuals, using a single case experimental design. (If you’re not familiar with this approach to research – it’s extremely rigorous and useful in a clinical setting, this link takes you to a chapter discussing its use).  The aim was to establish which part of treatment “did the work” to change behaviour, but also measured pain intensity, and fear of pain and movement.  The treatments were information about pain and mechanisms, and the activities were those the person particularly wanted to be able to do. Their findings identified that explanations do little to pain intensity, avoidance or fear – but what actually worked was doing graded exposure. In other words, experiencing something different, DOING that something different in the real world, was more effective than talking about why someone shouldn’t be afraid. A much more recent replication of this study was conducted by Schemer, Vlaeyen, Doerr, Skoluda, Nater, Rief & Glombiewski (2018) and shows the same result: doing trumps talking about doing.

When we sit down and take a cold hard look at what we do in pain management we can see that the field has to draw on a huge range of disciplines and fields of study to understand the problems people experiencing pain have. This is, in fact, why Bonica and colleagues first established the International Association for the Study of Pain, and why multidisciplinary (and now interprofessional) pain management teams and approaches were established. None of us can possibly hold all the knowledge needed to work effectively in the area. At the same time, as health professionals working with people, we do need to have some foundation knowledge about biology, disease, illness, psychology, sociology and anthropology. These areas of study inform us as we work hard to help people get their heads around their pain. Do we need to be experts in all of these fields? Yes – if you work completely in isolation. No – if you work within an extended team (whether co-located or otherwise). Pain research will continue to push our understanding ahead – and to be responsible health professionals, we must incorporate new understandings into our practice or we risk being unprofessional and irrelevant. I would go as far as to say we’re irresponsible and harming patients if we fail to incorporate what is known about pain as a multidimensional experience. It’s time to back away from temporary guruism and move towards a far more nuanced, and perhaps less flighty approach to understanding pain.

Pain science. No, it’s not a thing. Pain being examined through multiple scientific lenses: definitely a thing.

NB for the avoidance of doubt: pain is never a “thing” but examining pain through multiple scientific lenses involves many “things”. (Merriam-Webster – click)

de Jong, J. R. M., Vlaeyen, J. W. S. P., Onghena, P. P., Goossens, M. E. J. B. P., Geilen, M. P. T., & Mulder, H. O. T. (2005). Fear of Movement/(Re)injury in Chronic Low Back Pain: Education or Exposure In Vivo as Mediator to Fear Reduction? [Article]. Clinical Journal of Pain Special Topic Series: Cognitive Behavioral Treatment for Chronic Pain January/February, 21(1), 9-17.

Schemer, L., Vlaeyen, J. W., Doerr, J. M., Skoluda, N., Nater, U. M., Rief, W., & Glombiewski, J. A. (2018). Treatment processes during exposure and cognitive-behavioral therapy for chronic back pain: A single-case experimental design with multiple baselines. Behaviour Research and Therapy, 108, 58-67.

Wood, L., & Hendrick, P. A. A systematic review and meta-analysis of pain neuroscience education for chronic low back pain: Short-and long-term outcomes of pain and disability. European Journal of Pain, 0(0). doi:doi:10.1002/ejp.1314