Simple Explanation of Pain

This is a great, easy to follow video about chronic pain. It helps you understand what current research has been saying about chronic pain - thats its not a joint or muscle problem, rather a 're-wiring' of the brain perception of itself. In other words, the brain has become more sensitive than before.

During the past twenty years, research on chronic pain has significantly increased, with considerable advances in understanding its etiology, assessment, and treatment. These discoveries have important healthcare implications, when pain is one of the leading causes for why people seek out medical care. Pain is an even bigger influence for movement and manual therapies. Whether or not pain relief is your immediate goal, the fact remains that the majority of people who walk into your office experience some degree of pain and/or tension that they want help with.  This is why we must understand what pain is, and more importantly, what pain is not, when communicating with our clients.

For manual and movement therapists, knowledge of the anatomy and movement of the body becomes fundamental as well. This is a simple review of the most recent understanding of pain, providing a summary of some of the latest pain science research, and how both are relevant and applicable to you and your clients. It proposes explanations for phenomena where, with your treatment, your client’s pain may decrease, remain the same, or perhaps gets worse. Ultimately, understanding these phenomena will empowering to both you and your clients success in managing the pain in their lives.

Within roughly the last twenty years, neuroscience and pain science have discredited the belief that pain reflects the state of physical tissues (i.e. pain = tissue damage), a purely biomechanical explanation for pain (Gifford 1998, Lederman 2010). This is the major falsification reversed, in how we once believed and understood pain to manifest in the body. The International Association for the Study of Pain (IASP) defines pain as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.”

Simply put, pain is the brain’s perception of tissue damage (Butler and Moseley 2003). Perception is the key focal point, because pain is about how a person consciously and non-consciously creates meaning of his/her physical reality. This perception of tissue damage (i.e. pain) is modulated by a number of cognitive, emotional, and sensory inputs (Gifford 1998; Carlino et al. 2014).

When someone in pain walks into your office, they want answers to the following:

1.  What’s wrong with me?

2.  How long is this going to last?

3.  Is there anything I (the client) can do about it?

4.  Is there anything you (the practitioner) can do about it?

(Verbeek et al. 2004; Gifford 2014)

These questions are prompted by the underlying assumption that pain is the indicator for something “wrong” in the physical body. A number of hypotheses will be made (joint misalignment, degeneration, compression), so that a treatment regime can be identified designed to “fix” these physical morbidities. When experiencing pain health practitioners sensibly, but mistakenly, place all of our attention in the physical domain. Today, we see that this is a false conclusion that pain predictably represents tissue damage.

“Pain is an opinion on the organism’s state of health rather than a mere reflexive response to injury. The brain gathers evidence from many sources before triggering pain.”

-V.S. Ramachandran

One of the brain’s chief priorities is to keep the body safe and protected. Pain warns us of danger and compels us to take action to relieve and/or avoid that danger. This stimulus is known as ‘flight-or fight.’ Thus, the experience of pain is based on a prediction of danger that we are physically in, not how much we are actually going to experience. Even if there are no problems in the tissues, nerves, or immune system, you can still hurt if your brain concludes that you are in danger (Butler & Moseley 2003).

Historically, a class of sensory receptors called nociceptors were once, incorrectly, referred to as pain receptors. Nociceptors are receptors that require higher thresholds of stimuli to trigger an action potential, which in turn sends larger, more amplified signals to the central nervous system (CNS). These larger signals serve to get a person’s attention by acting as warning signals. The brain, though, can ignore input from the body, large or small, if the brain is either distracted enough or does not value the incoming messages. Because pain is context-dependent, the drama around pain, injury – whether real or perceived – will take priority in the brain’s attention. A notable example of this is seen with soldiers in the heat of battle who are shot but don’t feel pain until much later, once they are out of the dangerous environment.

The recovery from tissue damage includes the resolution of healing (particularly inflammation) and attenuation of nociception excitation. The process is not complete if the final stage of attenuation is not completed – and the system returns to homeostasis. The point is, that a time frame exists, and this is the expected cycle within which all tissues complete their healing phases. Pain serves an important role during healing to ensure the process is preserved, and to prevent further tissue damage in order to facilitate a full recovery (Lederman 2015; Figure 1).

 If pain persist past the healing window, it is considered chronic. It is important to reiterate, though, that an individual can experience acute pain even without tissue damage present. We can refer to this more accurately as a "pain event."

The neuromatrix theory of pain proposes that pain is an imprint, or “pain neurosignature,” of nerve impulse patterns. These patterns are generated by the body-self neuromatrix (Melzack 2001) and influence the structures, soft-tissue and functional activities. There are many inputs to the brain that can create or later trigger a pain neurosignature, including movements, thoughts, emotions, touch, memories, fears, smells, and visual stimuli, to name a few. Interestingly, the neuromatrix requires no actual sensory input for a person to experience pain, only the activation of a pain neurosignature or pattern that 'triggers' a response in the body; phantom limb pain is an example of this.

The most important takeaway from the neuromatrix theory of pain is recognizing that pain is an output of the brain rather than being dependent on or a response to sensory input like damaged tissue (Melzack 2001; Gatchel et al. 2007).

CONCLUSIONS

Our experience of pain is a top-down process—always. In fact, there is no such thing as myofascial pain, bone pain, organ pain, or even the existence of nerve pain. There’s just pain. This means damaged and pinched nerves do not have to hurt. Even in the presence of actual tissue damage—given pain is an output of the brain—it is our brain that concludes whether our tissues are in danger.

Pain is primarily a psychological experience (Craig and Hadjistavropoulos 2004). This is not to say that pain is all in your head, as in your discomfort is imaginary, but it is a construct of the brain projected onto the body. Modern pain science does NOT imply people imagine their pain.

Pain is real. Pain is always real. Pain literally changes our PNS and CNS physically and chemically. This is the dark side of neuroplasticity. Pain can be an output from our brain, that changes the input from the PNS and CNS. The resulting messages can then change the brain’s perception – a complicated ‘loop,’ with no end.