What we should know about pain science
There has been a paradigm shift of information that has come on to the medical and movement world as it pertains to pain science in the last 20 years. Unfortunately, most of it has not quite made it to the inner layers of academia, but the information is out there and to utilize for those of us who are interested in dealing with a huge segment of the population that needs our help. This article is written for the movement professional as an addendum to how we already treat and train our clients and patients.
What is pain?
For centuries (this includes what most people think now), pain was thought to come from sensors in the skin that detected pain and were sent to the brain for us to feel and thus do something about. In fact, the famous scientist Rene Descartes highlighted this supposed phenomena with the illustration to the left.
Unfortunately, this gross oversimplification of pain is highly inaccurate and the last 2 decades or so of neuroscience which utilizes fMRI have shown that pain is much more complex than 2+2=4.
So what is pain?
According to world renowned pain researcher and Australian Physiotherapist, pain “…is produced by the brain after a person’s neural signature has been activated and concluded the body is in danger and action is required.” Another definition of pain comes from a brilliant Psychologist by the name of Ronald Melzack. Melzack summarizes pain as:
“The neuromatrix theory of pain proposes that pain is a multidimensional experience produced by characteristic "neurosignature" patterns of nerve impulses generated by a widely distributed neural network-the "body-self neuromatrix"-in the brain. These neurosignature patterns may be triggered by sensory inputs, but they may also be generated independently of them. Acute pains evoked by brief noxious inputs have been meticulously investigated by neuroscientists, and their sensory transmission mechanisms are generally well understood. In contrast, chronic pain syndromes, which are often characterized by severe pain associated with little or no discernible injury or pathology, remain a mystery. Furthermore, chronic psychological or physical stress is often associated with chronic pain, but the relationship is poorly understood. The neuromatrix theory of pain provides a new conceptual framework to examine these problems. It proposes that the output patterns of the body-self neuromatrix activate perceptual, homeostatic, and behavioral programs after injury, pathology, or chronic stress. Pain, then, is produced by the output of a widely distributed neural network in the brain rather than directly by sensory input evoked by injury, inflammation, or other pathology. The neuromatrix, which is genetically determined and modified by sensory experience, is the primary mechanism that generates the neural pattern that produces pain. Its output pattern is determined by multiple influences, of which the somatic sensory input is only a part, that converge on the neuromatrix.”
While this may seem confusing at first, it basically means that all it takes for someone to experience pain is to have a neural signature activated and it is perceived by the organism as being threatening in some way.
So what is a neural signature?
A neural signature (or neurotag) is essentially a pattern of neural activity in the brain that allows us to put a sensory experience into a greater context. This context is filtered through our past, emotional context of the situation, our beliefs, consequences of this experience, and whether or not we perceive the information as dangerous to the organism or not.
There is no single pain center
The neuromatrix is where pain is perceived by humans. There is no one area of the brain. The neurosignature can be traced as a sensory experience goes from one brain region to the another for processing and then output. Brain areas that are part of the neuromatrix include:
A. Premotor motor cortex- which helps organize and prepare movement.
B. Prefrontal cortex- memory and problem solving.
C. Cingulate cortex- ability to focus and concentrate on a task.
D. Amygdala-Area where fear, fear conditioning, and addiction are processed.
E. Sensory cortex- Ability to discriminate between objects that are sensed by the periphery.
F. Hypothalamus and Thalamus- Stress response, motivation, and autonomic regulation.
G. Cerebellum- Fine tuning of movement and memory.
H. Hippocampus- Fear conditioning, memory, and spatial recognition.
I. Spinal Cord/Dorsal Root Ganglion-Acts like the bouncer. It can control the information the brain receives. The brain CAN actually control the amount of information it WANTS to receive. This can include increasing the amount of information the brain wants to hear as well as putting a damper on the information. This is important especially with hyper sensitization and CRPS for the former as well as how the bodies endogenous opiod system works in the latter.
There is no such thing as a pain fiber
It was once thought that (and illustrated in the Rene Descarte image) that there are pain fibers in the body in which when they are triggered, they would send a painful stimulus to the brain. While there are no pain receptors in the body, there are nociceptors that relay information to the brain regarding nociception and danger. Nociceptors relay information related to mechanical deformation of neural tissue, chemical changes, and thermal changes. This information is relayed to the spinal cord. It’s at the dorsal root where the information can be relayed via a interneuron and potentially on to a second order neuron if the information is deemed important enough. Once in the brain, this information goes through the neuromatrix for processing and then output or in human terms, perception and experience. So in other words, “No brain, no pain” and along those lines one doesn’t need a body to experience a pain. A useful exercise I do with my patients is to have them close there eyes and picture a dog, a white elephant, and an airplane. We can clearly see without eyes. We can also clearly smell, taste, and feel (including pain) without actually getting input from a sensory organ. So it’s clear that it is helpful to communicate with patients and clients where pain comes from.
But what about chronic pain?
Chronic pain is pain that has been experienced after 3-6 months. Most tissues heal within 6 months after an injury and thus nociception generally lessens/stops but quite often the patient still experiences pain. This is a huge population and can’t be ignored by us in the AFS (Applied Functional Science) community. It is estimated that there are 100 million adults in the US alone who experience chronic pain at any given time. This is a population that would benefit greatly from pain education and an novel approach to movement that GIFT fellows can deliver as we can tweak movements and individualize stress to tissues.
But shouldn’t we still tell patients about their anatomy and their injuries?
Maybe. Maybe not. But before you do, it might be in the patients interest to tell them that 40% of the general population has a significant bulging disc but no pain. 25-50% of the asymptomatic general population has any of the following:
-Assymetrical leg lengths and pelvis, and/or spine
-Facet joint degeneration
But wait, there is more! 35% of the population has tears in the rotator cuff, and by the time we are 70 2/3’s of us have asymptomatic tears in our rotator cuffs! Further more, there is about 50% correlation between knee pain and arthritis, while one study showed 35% of college basketball players with NO knee pain had significant damage shown on MRI.
We are not defined only by what a radiologist can find on a scan! Tissues heal and we are more robust that we think. By GIFTing patients with a basic understanding of where pain comes from and educating them we are ahead of the curve. GIFTing patients with mental ammunition that we can have pain and no tissue damage and also significant tissue damage with no pain, we can have patients and clients who can go about their lives with less chronic pain and more FUNCTION. This “mental ammunition” would include not using words that can re-activate a persons threat response or neurotag for their pain. Words that may increase threat response include terms such as:
-Wear and Tear
Instead, we could say something like: “As we age we get gray and our skin wrinkles. On the inside, things ‘gray and wrinkle’ but it doesn’t mean it has to hurt.” We already do a great job at GIFTing people with movement. By adding current pain science we are going to be only that much better with a huge patient population that needs our expertise.
-This isn’t a either or argument. Understanding pain can only help more people in pain.
-Recent neuroscience based on fMRI have shown that pain is an output of the brain.
-This pain is a complex experience (neurotag) that comes from many brain areas that may or may not mean there is still actual tissue damage.
-Tissues heal, but often an organism will still feel there is a perceived threat and hold on to a neurotag of pain much like a computer keeps playing the same program over and over again.
-Chronic pain is pain that persists after 3-6 months after healing of tissue.
-Chronic pain means we are dealing with more than just tissue and pain science education is very helpful at more quickly mollifying pain perception.
-We are in a place where we can use AFS plus pain neuroscience to affect ~100 million people
-Keep up the great work!
Female patient of 55 years of age. Comes to clinic complaining of full body pain of 8/10 especially pain the back, neck, and shoulders. Owner of the clinic evaluated her and was unable to get much information as the patient had panic attacks and generally fearful of movement secondary to increasing pain and fear of increasing pain. X-ray and MRI negative. Major diagnosis as per referring MD is obesity, Fibroymalgia and Chronic Fatigue. She also has experienced PTSD as she was a victim for 20 years of violence from her now deceased husband.
Upon first visit with this therapist, patient was waiting in waiting room and extremely anxious. In fact, her daughter said her mom was just about to leave secondary to increased anxiety and pain at 8/10. This therapist, approached and sat with patient and talked in a quiet and non threatening voice and small talked with patient for a few minutes. Then, this therapist asked the patient what she wanted out of therapy and how to proceed. She said she wanted to walk on the treadmill. So we did. 5 minutes forward and 5 minutes backward which decreased her perception of pain to a 5/10. We did a few other simple exercises including sit to stand, and played catch with a lightly weighted medicine ball on the rebounder. After 30 minutes of treatment which only included movements she wanted to do, her pain was a 2/10.
Patient was seen twice a week for 4 weeks. During this time, the patient was felt to be in charge of her treatment with this therapist being a facilitator. I talked about pain and where pain comes from and why we have pain and how it can be managed without medication. The patient understood and slowly started to be able to do more and more with her ADL’s. By week two she was cooking and cleaning around her house by herself which she has not done in a long time. She drive independently by week 3 which is something she has not done in 2 years. By week three she walked outside in her neighborhood independently which was also new to her. By discharge, patient was eager to join a gym and continue her own therapy. By this time, patient’s pain level around the house was no more than a 2/10 which occasionally went to 0/10. This is remarkable as the patient had chronic and severe pain for over a decade that medications couldn’t quell. It was the down regulation of the perception of pain utilized via chronic pain education, putting client in charge of her therapy, and simple functional movements that helped patient the most it seems.
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A neuroscience approach to managing athletes with low back pain.Puentedura EJ1, Louw A.
Resources for more information.