Two foods I love eating regularly (and that’s probably not a good thing for the latter) are tuna and ice cream. Thankfully, I have a firm grasp of the concept that some things just weren’t made for mixing.
You might think this is a funny way to start a blog post on CRPS… but I promise you the Adelaide heat hasn’t fried my brain. I contend that my tuna-ice cream metaphor might help us to understand why some interventions treating CRPS may not be working.
We recently published a systematic review and meta-analysis that looked at the effects of graded motor imagery (GMI) on chronic pain, where the majority of participants in the included studies had CRPS . By pooling the results of two RCTs  we found positive results for GMI in reducing pain. Our results, however, are in stark contrast to those found in a recent clinical audit of CRPS patients using GMI, done by Johnson et al. . In this study, participants reported very little improvement in pain scores and only minimal improvements in function following the intervention. (See our articles page to download PDFs published by the BiM team.)
That this study did not replicate the findings of the previous RCTs may be a result of differences in methodological rigour (for example, see what Simon has written here). Participants in this study seemed to not complete GMI, not do GMI properly, or do GMI as part of a variable programme. The fact that participants ‘received GMI, in conjunction with a range of other “best practice” physical and psychological interventions’ brings me back to my tuna-ice cream metaphor. Just as tuna and ice cream are nice foods when eaten separately, we have reasonable evidence to support the use of GMI and other ‘best practice’ interventions  to treat CRPS, when used as separate treatments Together though, I’m not so convinced.
Sometimes using a combination of treatments can be counterintuitive to one another. For a patient with CRPS that experiences catastrophic pain with light touch, tactile discrimination training (TDT) may not be an appropriate intervention. Because GMI is an intervention that doesn’t require tactile stimulation, it provides a step back from something like TDT. While there is good evidence to suggest these two interventions work when used separately, the combination of the two doesn’t equal double the benefits.
Of the thirty-five participants in the Johnson et al. paper, only eighteen completed the three stage GMI protocol; the other seventeen participants completed the first one or two components of GMI, either as stand-alone treatments or in conjunction with other interventions. All thirty-five participants were statistically analysed as a group.
After reading through the study a few times, I came to one bold conclusion – if GMI associated with a range of other interventions doesn’t work, then perhaps all of the interventions being done at these centres don’t work? If this is the case, then perhaps we should try doing nothing? What if we turned away patients with CRPS? See what happens to their NRS pain data when they go untreated? Of course, my common sense (and moral grounding!) tells me this wouldn’t end well either.
All in all, I think the conclusion of this study may appear a little precocious. To me, the results say that tuna-ice cream is bad, tuna milkshakes are bad, tuna chocolate truffles are bad, and rum and tuna are all bad. However, they’ve still come to the conclusion that tuna itself is bad. If we are going to accept the possibility that tuna is bad, then we also need to accept the possibility that ice cream, milkshakes, truffles, and rum might also be bad.
Jane has an addiction to Vegemite, loves ice-cream, and tuna (but only dolphin-free!), and has just started her PhD at BiM. After finishing her Physiotherapy degree with Honours and working clinically for a year, Jane is now back into pain. Researching, not inflicting, that is. She is interested in pelvic pain, but the rest of her PhD story is yet to unfold.
See our articles page to download PDFs published by the team.
 Bowering KJ, O’Connell NE, Tabor A, Catley MJ, Leake HB, Moseley GL, & Stanton TR (2013). The effects of graded motor imagery and its components on chronic pain: a systematic review and meta-analysis. The journal of Pain, 14 (1), 3-13 PMID: 23158879
 Moseley GL (2004). Graded motor imagery is effective for long-standing complex regional pain syndrome: a randomised controlled trial. Pain, 108 (1-2), 192-8 PMID: 15109523
 Moseley, G. (2006). Graded motor imagery for pathologic pain: A randomized controlled trial Neurology, 67 (12), 2129-2134 DOI: 10.1212/01.wnl.0000249112.56935.32
 Johnson S, Hall J, Barnett S, Draper M, Derbyshire G, Haynes L, Rooney C, Cameron H, Moseley GL, de C Williams AC, McCabe C, & Goebel A (2012). Using graded motor imagery for complex regional pain syndrome in clinical practice: failure to improve pain. European journal of pain, 16 (4), 550-61 PMID: 22337591
 Daly AE, & Bialocerkowski AE (2009). Does evidence support physiotherapy management of adult Complex Regional Pain Syndrome Type One? A systematic review. European Journal of Pain, 13 (4), 339-53 PMID: 18619873