Complexities of Pain

On the 24th January 2013, Fox aired the latest episode of Greys anatomy, which featured Arizona struggling with phantom limb pain following her above knee amputation.  It showed Arizona struggling to come to terms with pain in a limb that was no longer there, often referring to herself as ‘crazy’.  While shows can sensationalize content, the storyline comes from a very real struggle with pain, and how it can be potentially treated by mirror therapy.

Phantom limb pain like any pain is real.  Yes, let’s get that straight before we continue; all pain is real.  However, phantom limb pain is a good example of the brain’s role in the experience of pain.  The brain has a dedicated map of the whole body and this map, along with several other key brain areas, is used to create a pain experience whether the pain is acute and related to a tissue injury or if it is chronic and the tissue injury has healed.

Typically, when a body part is injured, specialized nerves called nociceptors become excited and send a signal to the brain warning us of the damage.  This can even happen when there is no damage!  Based on these incoming signals along with many other factors such as where you are, how you feel, your expectations, previous experiences, memory etc, your brain decides whether to produce a painful experience or not.  There are many times when your brain will choose not to create pain, think of the times you’ve woken with a bruise and thought “huh, where did that come from?” or times when you’ve been playing sports and then you come off the field to find you’re covered in scrapes, marks, cuts etc.  Equally, sometimes you may be sitting there watching TV, minding your own business when you get a sudden sharp pain strike down the leg.  Interestingly, nociception does not always lead to the brain creating pain, and pain can occur without nociception.

Unfortunately, our recent advances in our understanding of pain has led to some people giving the message ‘pain is in your head’, which is then often misinterpreted as ‘you are making this up’.  This is entirely untrue and as mentioned above, all pain is real.  However, we must understand that pain is an output of the brain based on all the information that the brain receives.

Pain is far more complex than tissue injury = pain.  As pain continues, several other physiological changes can occur which cause nociceptors in the periphery (outside the spinal cord) and spinal cord as well as brain areas to change how they function.  This results in a very real experience of pain, however the ‘origin’ of the pain is now much more complex than the original injury and often is out of proportion to the injury.

This new understanding of mechanisms that keep a brain producing pain is leading us to new approaches in dealing with pain.  Once any serious injury/disease has been ruled out and tissues have healed as best they can, we need to explore alternative avenues in the management of pain.

Last night, we saw Arizona using both mirror therapy and visual illusions/virtual reality. Recently, these treatments are showing promise within the research field.  Professor Lorimer Moseley and David Butler, pain clinicians and researchers from Australia have looked at mirror therapy (which is actually one part of a more extensive rehabilitation program called Graded Motor Imagery) and locally, Professor Diane Gromala at Simon Fraser University heads a research team investigating the use of virtual reality for pain relief.

Image credit: Boaz Joseph /The Leader

Image credit: Boaz Joseph /The Leader

Hopefully as our understanding grows, new treatments will develop that can help people who live with these pain conditions have a better quality of life.

Written by: Roland Fletcher, Registered Physiotherapist

 

See a successful story using mirror therapy here