Why is it that, after extensive Physiotherapy, massage therapy, chiropractic, osteopathy and other forms of treatment people still experience pain? Research studies are still working on getting to the bottom of persistent pain, why some have it and others don’t.
The answer to the question is that pain and our experience of pain is complex. For this article I want to focus on body perception disturbance.
In order to have a better understanding of what we are talking about, I need to talk a bit about the brain, anatomy and physiology. My plan is not to go into great depths because that would turn this blog into a series of novels. So a brief overview and if this sparks your interest then I encourage you to research and learn more.
Let’s start with the sensory-motor cortex in the brain. The sensory cortex is the part of the outer brain that receives signals from the body regarding sounds, sights, smells, touch, vibration and where our body is located in space (1). It is also involved in planning movement.
The Motor Cortex is also located on the outer part of the brain, right beside the sensory cortex and its involved in planning, controlling and executing movement (2).
Another component of the brain involved in body perception is the cortical homunculus, which is a distorted representation of the body and its parts based on use and need for accurate sensation and movement. For example on the picture you will notice the representation of the hands is much later than the lower back. One reason for this is that the hands need to be able to perform fine coordinated movements and we use our hands very frequently where as we don’t need as much attention to move our lower back.
Some individuals with persistent pain have a distortion of their body perception which is defined as the feelings of one’s own body (3). Studies have found that some individuals have re-organization of their sensory-motor communication within the brain making it difficult to make sense of the sensation and movements of a particular body part.
An analogy I like to use is imagine you had a clear google map of where you were going and then all of a sudden that google map went all blurry. How difficult would it be for you to move around and sense where you are in the world? Now imagine it’s the map of your hand. Would your hand move coordinated? Would your hand experience sensations in the same way it did before? Likely not, and that why some individuals develop what is called complex regional pain syndrome or CRPS in their arm/hand following an injury. CRPS is characterized by a disproportionate experience of pain, unexplained swelling and discolouration of the skin and an inability to even be touched lightly due to pain.
When researchers discovered this reorganization in individuals with CRPS they began to wonder if the same could happen to low back pain sufferers. Can the brain change in individuals with chronic or persistent low back pain? The answer is yes. Studies have found that some individuals with low back pain have reduced accuracy of touch (3), meaning when the therapist touches their back they cannot correctly identify where they were touched or if the therapist draws letters on their back they cannot correctly identify the letters.
Individuals with back pain also cannot sense their back very well (either it feels bigger, smaller or swollen) and they have difficulty coordinating movement between the upper and lower part of the spine (3). Individuals might describe that they have to think really hard about making their back move the way they want it to or the right and left side feels lopsided. These reports are indications that changes may have occurred in the sensory-motor cortex and the homunculus map has “smudged” or gone “blurry.” (3)
So how might a therapist know if your body-perception has changed? Well we don’t have access to functional MRI’s and other expensive equipment so researchers have worked on creating a short questionnaire that can screen clients for body perceptions changes. The questionnaire is called the Fremantle Back Awareness Questionnaire or the FreBAQ. I have now implemented this questionnaire in my practice not just for low back pain but other types of pain so that I might be better able to direct treatment. Some other ways we can test for changes includes having the person identify where we are touching with their eyes closed, what letters we are drawing on the skin and/or 2-point discrimination. I also like to use other questionnaires to help support the overall picture of why a person is having pain.
Going back to the initial question at the beginning of this blog. Why do some people not get better after extensive treatment and exercise? While treatment and exercise are key components in rehabilitation if someone has body perception distortion this requires a different approach to help that individual essentially “refresh” their google map. There are a variety of ways to do this using sensation and movement strategies that are new and interesting. It is about increasing body awareness and bringing mindfulness to movement and sensation.
So if you’re an individual who’s completed extensive treatment perhaps body perception is a problem and finding a therapist that has an understanding of this might be helpful in your healing journey.
- Wikipedia https://en.wikipedia.org/wiki/Sensory_cortex
- Wikipedia https://en.wikipedia.org/wiki/Motor_cortex
- Wand et al. Assessing self-perception in patients with chronic low back pain: Development of a back-specific body-perception questionnaire.