Tuesday, October 16, 2012

Digesting the Moose Jaw adventure: Part IV, nature of pain

Older posts in this series:


Digesting the Moose Jaw adventure: Part I
Digesting the Moose Jaw adventure: Part II (NERVES, baby..)
Digesting the Moose Jaw adventure: Part III - Sensory testing for neuropathic pain


Susan Tupper PT PhD presented several times at the Interprofessional Management of Neuropathic Pain Conference in Moose Jaw, this past weekend. She is UWO- trained PT, who moved to Saskatoon, and this past year attained a PhD at U.Sask for her work developing pain assessment and pain pattern recognition tools for children with juvenile rheumatoid arthritis. 

Susan's presentation "Understanding Influences on Pain Scores: What do I do with a 15/10?" was one of the best of the whole weekend, for her clarity about something ambiguous, her careful delineation of that which is normally confusing and convoluted  - explaining pain. Susan explained there was a difference between pain perception and pain expression; pain is not a "thing", rather it's a conundrum, which although universal, is difficult to define, and cannot be directly measured - all that can be measured is pain behaviour or expression. Ever. The perception of pain, though not directly measurable, can be vivid and describable. There is no predictable relationship between pain expression, pain severity, or tissue damage. If you take neonates, give them sucrose while inflicting a painful stimulus, their expression of pain decreases, but their EEGs are exactly the same as neonates not given sucrose (Slater 2010). 

Why do we need pain perception in the first place? The brain needs a way to learn what is and is not harmful to its organism. 

Brains are busy places, dealing with huge amounts of information flow every second of their life spans. A brain needs a way to prioritize; pain perception demands, then focuses its attention. The brain has to deal with multiple inputs from absolutely everywhere, so, pain perception serves as a short cut with which the brain might access, then deploy, its own survival array. 

What about pain expression? "Effective communication of pain is required when others can help achieve these goals." (Williams AC 2002). Pain expression has a social basis! It's to communicate! The social role of pain expression and communication is two fold: solicit comfort, and warn others that the associated action was harmful.

Pain is modified by context: the nature of the threat, severity of injury, the cost of expression, and social context. 

All we can measure is pain expression. We can elucidate factors contributing to it.. 

Social Context: 



  • Age (Gagliese & Kart 2003) (Couldn't find reference)
  • Sex (Gagliese et al 2006) (couldn't find reference)
  • Cost of expression (Johnson et al 2011, 1999) (Couldn't find)

A model of the integration of pain perception and pain assessment factors was done by Hadjistavropoulos T and  Craig, K. D.  in 2002, and 2011. Susan provided a version based on theirs, and reproduced by me, below: 

It's a great model of a treatment dyad, actually. 
I don't think the original trauma needs to be "tissue" actually - could be any sort of trauma. 

She also discussed Melzack's neuromatrix model of pain

  • Sense of self is genetically determined and any variance from this is going to be interpreted as a threat by the brain: pain is a learning experience, and its perception is an output, a noxious output to motivate continued behaviour change
  • Sense of self is modifiable by experience, cognitions, emotions
  • The neuromatrix can output pain in the absence of external stimuli
Vision and perceptual illusions can teach us about pain.  (Try to make these balls stop moving. I bet you can't. It's an illusion, and very powerful. Our brain can't help but default to it.)

Visual illusion posted to/ discovered on Facebook
Not the same one Susan used
About neuropathic pain, she said its mechanisms don't depend on "cause", different mechanisms can produce the same symptoms, multiple mechanisms can be involved in a single individual, and we rely on mechanism based-approaches to treatment rather than disease-based approaches.

Features of neuropathic pain include 

1. Ectopic nerve activity (spontaneous firing due to lowered threshold, which itself is based on many mechanisms, or inflammation, e.g., activity by glial cells) resulting in
  • ongoing spontaneous pain
  • sudden bursts of shooting pain
  • burning pain
2. Central sensitization or hyper-excitability in the spinal cord, which includes post-synaptic problems resulting from ongoing peripheral activity, loss of inhibition, or of inhibitory neurons. 

There are phenotypes of neuropathic pain described by Baron, Binder, Wasner in Neuropathic pain: diagnosis, pathophysiological mechanisms, and treatment, Lancet 2010

So, what one does with a 15/10, is:

A. recognize the motivation behind the communication

1. Allow patient to tell story and express needs (Meldrum, Tsao, Zeltzer 2009) 
2. Reassure patient of purpose and limitation of pain measurement (Van Oosterwijck et al 2011) 
3. Develop a therapeutic alliance (Hall et al 2010; Daniels and Weardon 2011)

B. modify pain output with a multi-modal approach (Panerai AE 2011)

1. Pharmaceutical 
2. Physical (exercise, manual therapy, modalities) 
3. CBT 
4. Homeostatic hygiene (sleep, diet, exercise, stress reduction)


Pain is difficult to describe. People try anyway, through art and through metaphor. Pain expression is social communication. This communication needs to land somewhere. Neuromatrix theory tells us pain is an output from the non-verbal part of the brain that gives rise to a self concept. Visual illusions can tell us a lot about how the brain works. Many many mechanisms can contribute to a pain experience and to unusual pain presentations. A multi-modal approach to treatment seems to work best. 

1.Rebeccah Slater, Laura Cornelissen, Lorenzo Fabrizi, Debbie Patten, Jan Yoxen, Alan Worley, Stewart Boyd, Judith Meek, and Maria Fitzgerald; Oral sucrose as an analgesic drug for procedural pain in newborn infants: a randomised controlled trial. Lancet. 2010 October 9; 376(9748): 1225–1232. (Open access)

2. Williams AC; Facial expression of pain: an evolutionary account. Behav Brain Sci. 2002 Aug;25(4):439-55; discussion 455-88.

3. Azize PM, Humphreys A, Cattani A.; The impact of language on the expression and assessment of pain in children. Intensive Crit Care Nurs. 2011 Oct;27(5):235-43. Epub 2011 Aug 20.

4. Julie E Goodman, Patrick J McGrath;  Mothers’ modeling influences children's pain during a cold pressor task. Pain Volume 104, Issue 3, August 2003, Pages 559–565

5. Pim A.M. Peeters,Johan W.S. Vlaeyen;  Feeling More Pain, Yet Showing Less: The Influence of Social Threat on Pain.  The Journal of Pain Volume 12, Issue 12, December 2011, Pages 1255–1261

6. T Hadjistavropoulos, K.D Craig;  A theoretical framework for understanding self-report and observational measures of pain: a communications model. Behaviour Research and Therapy Volume 40, Issue 5, May 2002, Pages 551–570

7. Hadjistavropoulos, H. D., Williams, A., Craig, K. D. (2011). Clinical Pain Management. In Lynch, M. E., Craig, K. D., Peng, P. W. H. (Eds.). Clinical Pain Management ( pp.200-206). Oxford: Wiley-Blackwell.

8. John W. Burns, Phillip Quartana, Stephen Bruehl; Anger Suppression and Subsequent Pain Behaviors among Chronic Low Back Pain Patients: Moderating Effects of Anger Regulation Style. ANNALS OF BEHAVIORAL MEDICINE Volume 42, Number 1 (2011), 42-54, DOI: 10.1007/s12160-011-9270-4

9. Ceilidh Stapelkamp MPH, Bernie Carter PhD, Jenny Gordon PhD, Chris Watts MA; Assessment of acute pain in children: development of evidence-based guidelines. International Journal of Evidence-Based Healthcare Volume 9, Issue 1, pages 39–50, March 2011 (Full access)

10. Ronald Melzack; Pain and the Neuromatrix in the Brain. Journal of Dental Education, Volume 65, No. 12, pages 1378-1382 (open access)

11. Ralf Baron, Prof, MD,  Andreas Binder, MD, Gunnar Wasner, Prof, MD; Neuropathic pain: diagnosis, pathophysiological mechanisms, and treatment The Lancet Neurology - Volume 9, Issue 8 (August 2010)

12. Marcia L. Meldrum, Jennie C.-I. Tsao, Lonnie K. Zeltzer; “I Can't Be What I Want to Be”: Children's Narratives of Chronic Pain Experiences and Treatment Outcomes.  Pain Medicine, Volume 10, Issue 6, pages 1018–1034, September 2009

13. Jessica Van Oosterwijck, Jo Nijs, Mira Meeus, Steven Truijen, Julie Craps, Nick Van den Keybus, Lorna Paul;  Pain neurophysiology education improves cognitions, pain thresholds, and movement performance in people with chronic whiplash: A pilot study. Journal of Rehabilitation Research & Development, Volume 48, Number 1, 2011 Pages 43–58 (open access)

14. Amanda M. Hall, Paulo H. Ferreira, Christopher G. Maher, Jane Latimerand Manuela L. Ferreira; The Influence of the Therapist-Patient Relationship on Treatment Outcome in Physical Rehabilitation: A Systematic Review. Physical Therapy August 2010 vol. 90 no. 8 1099-1110 (Full text)

15. Jo Daniels and Alison J. Wearden; Socialization to the Model: The Active Component in the Therapeutic Alliance? A Preliminary Study. Behavioural and Cognitive Psychotherapy  / Volume 39 / Issue 02 / March 2011, pp 221-227

16. Panerai AE;  Pain emotion and homeostasis. Neurol Sci. 2011 May;32 Suppl 1:S27-9.


*I really hope that the references I have found to link here are the same ones Susan was thinking of in her presentation. I haven't asked her to check them. Plus there were a number that simply eluded me. 

Next in the series, Dr Chakravarti from Saskatoon on the topic of mindfulness. 

1 comment:

Unknown said...

thank you for sharing--very educational.