By: Ricky Singh – February 18, 2014
Moseley & Butler’s Explain Pain came highly recommended by many of my mentors. Explain Pain does an excellent job illustrating current concept concepts in pain science and is very easy to understand for both the health care professional and patient. If you are intrigued by what you have read in this summary, I would highly recommend purchasing the book so you can see the beautiful illustrations and artwork that is included throughout the book by a phenomenal artist (Sunyata).
What is pain?
Pain is an experience or an output that is felt when a person is in danger. It is a decision that only the brain can make once it has processed all relevant information. You can break a bone, sever a nerve or tear a muscle but you won’t experience pain if your brain does not think you are in danger. The primary purpose behind why pain exists is to motivate you to take action against threat, ultimately keeping you out of harms way.
The authors make reference to several cases in which people are in catastrophic events and experience no pain.
- The athlete who fractures a limb while in the final seconds of a game and continues playing without pain
- Surfers who have had their legs bitten off by a shark and only reported feeling a bump at the time.
Pain is Context Dependant
Consider two individuals, one a pianist and one a professional dancer. If both sustain the same finger injury, which individual’s finger do you think will hurt more? The pianists because finger damage poses a greater threat to the pianist compared to the dancer. In this way, context gives meaning to the pain response.
The authors make reference to “Ignition Cues” which are environmental sensory cues that serve to kick start the pain experience. An example of this is pain being influenced by who is around. Males have been shown to have greater pain thresholds if being tested by a female. Another example being someone experiencing pain when the boss is present at work.
The Physiology of Pain
Sensors are spread out throughout your entire body. These sensors are specific to certain types of stimulation (mechanical, temperature, chemical). These sensors, when activated, carry information to the spinal cord about what is going on in the tissue. Nociceptors are specialized sensors which respond to a variety of different stimuli. Regardless of the stimuli, the message is always the same, which is “DANGER.” The information goes up to the spinal cord and is relayed to the peripheral nervous system’s minibrain, the dorsal root ganglion. This is the first area where information is evaluated and/or modified. The information is then relayed to the brain, at which time a very complex process happens. The brain evaluates the information by looking at memory, emotional context, consequences and reasoning. It very quickly consults with the premotor/motor cortex, cingulate cortex, prefrontal cortex, amygdala, sensory cortex and several other areas before making a decision. If the brain concludes that the threat is real, then it will output a pain signal. Several systems are involved in the expression of pain such as the endocrine, motor, autonomic and immune systems.
What is important to note here is that humans do not have pain pathways, pain receptors or pain centers in the brain.
“Nociception is neither sufficient nor necessary for pain”
Recent brain imaging studies have shown the activity patterns of individuals experiencing pain varies from person to person. There are no specific pain centers but rather areas of the brain, which are considered ‘ignition nodes’. These areas are the same areas of the brain that are used for sensation, movement, emotions and memory. Pain hijacks these areas to express itself.
Central Sensitization & Chronic/Persistent Pain
Sensors are designed to pass information to the brain as efficiently as possible. Sensors only live for a couple of days and adapt frequently, change thresholds, stay open longer and even increase in number. The system is always adapting to keep you out of harm.
more danger = more sensors = more sensitivity = more pain
The authors make reference to pain neurotags, which the brain is able to activate in response to a familiar stimulus. For example, you have a painful experience in a specific context, the brain stores the information in the brain as a neurotag and can be activated if the same stimulation is perceived by the brain in the future. The brain becomes efficient at producing pain the more the neurotag is activated.
Factors which increase sensitivity of receptors contributing to persistent pain:
- Autonomic Nervous system (sympathetic vs parasympathetic)
- HPA Axis/Endocrine System (excess cortisol/adrenaline)
- Immune System (high levels of pro-inflammatories)
Increased stress levels, being labeled with a diagnosis, your beliefs about your pain, activity levels, previous episodes all have an implication on your pain.
Authors make reference to “Thought Viruses” which are beliefs that are powerful enough to maintain a pain state.
“Im in pain so there must be something harmful happening to my body”
“Im not doing anything until the pain goes away”
“The CT machine couldnt find it so it must be bad”
Modern Management of Chronic/Persistent Pain
The goal is to get individuals moving, without activating pain neurotags. The human body is designed to move. Appropriate movement that is planned and graded, will help reduce central sensitization and decrease pain.
The first step in helping someone in chronic/persistent pain is by understanding the relationship between his or her pain and activity level.
Education, knowledge and understanding provide the foundation for therapeutic movement. These 3 elements also reduce the threat associated with pain. No patient should be performing painful movement if they don’t understand why they hurt.
“Educated movement is brain nourishing, because it establishes and re establishes fine functional sensory and motor representations in the brain, using pathways laid low by fear and ignorance”
Education and Understanding
Start by educating the patient and debunking myths about pain. For example:
- No pain no gain attitude- some pain during rehab may be appropriate however you need to understand the balance
- Let pain be your guide – WRONG – if chronic pain patients followed this they would do nothing. They have to take control of their pain.
Things to keep in mind:
- Pain physiology can and must be explained to all patients regardless of their academic backgrounds
- Knowledge of pain physiology reduces the threat value of pain – reduced threat means reduced activation of protective systems
- Combine pain physiology education with movement approaches to improve physical capacity and reduce pain
- Need to allow for deep learning to take place. Information must be retained understood and applied – need to know WHY things hurt and integrate knowledge into attitudes and beliefs
Smart Thinking (Your hurts won’t harm you)
If you are hurting, or hurting more than normal, that does not mean your tissues are being injured more so. Recurrent pain is often protective in nature and does not mean your tissues are experiencing additional damage.
At this stage, it is important for the patient to understand what is triggering their pain and what factors are contributing to it.
Pacing and Graded Exposure
Movement is essential for the health of all body systems and processes. Movement needs to be a graded process because pain can be debilitating if pushed too far. The authors recommend the following steps:
1) Decide what the patient wants or needs to do more of (swimming, cycling, walking the dog etc.)
2) Find your baseline. Find the sweet spot at which you can perform the activity without a flare up
The Virtual Body
A virtual representation of each body part exists in the brain, known as the virtual body. When experiencing chronic pain, an individual may begin protecting that are of the body by guarding or limiting activity. The result of this type of behaviour is a ‘smudged’ representation of that specific part of the virtual body in the brain which is distorted and less defined. The goal of rehabilitation is to reintroduce movement, either visually or physically, to stimulate the virtual body in the brain to begin dissociating the act of movement from pain neurotag. It is important to understand that with some patients even the smallest movement can be aggravating. In this scenario, begin with visual tasks (ex. imagine raising your arm up without actually performing the movement).
Take Home Points:
- Pain is an output of the brain and does not relate to degree of tissue injury (more pain does NOT equal more harm)
- It is important to discuss the difference between hurt vs harm with your patients (it may hurt, but it may NOT be harmful)
- It is important to educate patients regarding why they feel pain and why it persists even though the tissues have healed.
- Avoid giving patients diagnostic labels like fibromyalgia or chronic fatigue syndrome. This may cause further fear avoidance, stress and dependence on the medical system. Listen to your patients and understand what they are experiencing.
- Make sure the patient understands that they have control over their pain. Work with them to develop a movement based program to help dissociate the pain neurotic
(This summary was posted with permission from the authors and publisher)