Explaining Pain - Making more sense of how we perceive pain.

Pain is our alarm system protecting us from danger. Physical therapy can help you manage chronic pain.

Understanding pain, especially for those experiencing chronic pain (defined as pain experienced longer than 3 months) may seem like a monumental and almost impossible task. There have been a variety of studies to try to better understand pain - and the findings show that there is more to our perception of pain than the biological experience. Meaning that although disease or injury contribute to our perception of pain, they are not the only variables.

Current research explains that our nervous system takes into account many variables in addition to disease or injury, to increase or decrease the pain we feel. The theory is that pain is our alarm system with a volume knob that protects us and therefore motivates us towards safety. Create more danger, the volume gets turned up - create more safety and the volume gets turned down.

Researchers have coined the term Protectometer and state: 

We will experience pain when our credible evidence of danger related to our body is greater than our credible evidence of safety related to our body. Equally we won’t have pain when our credible evidence of safety is greater than our credible evidence of danger (Moseley and Butler 2015).

At some point, many people experiencing chronic pain have heard or felt that “it’s all in your head” or “you’re exaggerating." Pain is REAL. The same researchers that explain pain with the protectometer also describe DIMs (Danger In Me) and SIMs (Safety In Me). DIMs and SIMs help elaborate on the biopsychosocial concept of pain. We more easily relate to the biological part of pain where injury = pain. (Which isn't always true precisely because of the psychological and social aspect that must also be addressed.) We are consciously and unconsciously assessing DIMs and SIMs all the time.  Since many of these assessments are unconscious, we can not “think” our way out of pain - however, the more you learn and become aware of your protectometer system, the more in control you will be. 

One way of approaching DIMs and SIMs is by categorizing them into four themes. DIMs and SIMs are individual to each person. What is dangerous to one person, may be safe for another - which is why, in these examples, some DIMs and SIMs are the same. 

	DIMs	SIMs
Engaging with the environment	Physical environments - garden (too many obstacles) Social environments - friends and family (stress inducing) Healthcare environments -negative experience, this means something is wrong	Physical environments - garden (quiet and peaceful)  Social environments - friends and family (I feel supported by them) Healthcare environments -positive experience, this means I will get help
In my body	Health concerns (What’s wrong with me?) Negative sensory experience:  Cramping, stiffness	Reassurance (swelling means my body is healing) Positive sensory experience: warm bath, aromatherapy
My emotional health	“I feel out of control” “Anything I do could cause more injury.”	“I can get through this.” “The pain experience can change.”
Activities and behaviours	Activity limitations/triggers - going for a long ride in the car.	Enjoyable activities Seeing progress in activity tolerance Productive activities

Another consideration is the concept of neuroplasticity. “Neuro” refers to our nervous system, “plastic” refers to the ability of the nervous system to change - this is how we learn and adapt. If pain is communicated and regulated within our nervous system, we can alter our sensitivity to pain stimuli (or DIMs) over time by recognizing and creating more SIMs. 

Understandably, this sounds like a very simplistic explanation of pain, but combining this information with other details and treatments specific to your experience is how your therapist at Foothill Physical Therapy will guide you towards your goals and a better quality of life. 

References:

https://www.noigroup.com/noijam/dim-sims/  (Protectometer link above)

Kennedy H, Harvie DS, Coppieters MW. Do threats and reassurances reside in the biological, psychological or social domain? A qualitative study in adults and young people with chronic pain. British Journal of Pain. 2024;18(6):472-481.