Threat Level Extreme
Is pain a manifestation of a heightened perceived level of threat?
Remember that we learn what is threatening from our previous experience so we can make better decisions it in the future. But sometimes that learned behaviour sticks even after the tissue has healed of the stimulus is removed. Simply believing that something is dangerous or threating will influence our behaviour, even though it is completely safe.
This is true for pain also.
Anticipation is a sub conscious neural process that plans how we move and predicts the likelihood of how it will feel. When you reach for a glass from the shelf, your brain is already planning the complex sequence of movements, the precise amount of contraction required, and the speed of the movement required to do this correctly. This is a learned process. At the same time, there is also a prediction about how heavy that glass will be and what it will feel like, therefore we anticipate the sensory stimuli. These predictions influence how we plan out movement adjust our behaviour and perceive pain.
Importantly, all this processing is happening prior to receiving the actual sensory input from grabbing the glass. This is a top down process, pain can be a bit like this too.
Add an episode of shoulder pain into the mix. Now we have learned that raising our arm above our head, could be painful, therefore, the movement planning and sequencing will change. This might be helpful in the short term, but if this is persistent there is an important transition from tissue-based injury to processing errors in the CNS.
Top-down predictions prepare the body for the level of perceived threat as a protective mechanism to protect the body from damage rather than waiting for the nociceptive stimulus to arrive (Wiech et al., 2008) as suggested in bottom-up or tissue based models.
Have you shivered before getting into an ice bath or a cold shower? This is an example of anticipating and predicting the sensory stimuli based on previous experience and expectation, prior to receiving the sensory information from the cold water.
Take low back pain for example… If a person has previously experienced an episode of back pain from lifting a box, they have learned that this could be a dangerous task/movement. Therefore, prior to even lifting that box, there is an anticipation of pain prior to any tissue damage that evokes a response. This response may be altering movement, increasing sensitivity, increasing muscle guarding, or even total avoidance. This anticipation of pain is linked to prior experience and expectation that influences behaviour before tissue damage or nociception occurs as a maladaptive learned response.
The more a behaviour is reinforced, the stronger it becomes. But if we can shift from threat, to safety, to curiosity then perhaps we can create a window for our patients to be more curious about pain and movement. It is curiosity that promotes learning. Being curious about challenging different movements can assist breaking maladaptive pain cycles.
Have you thought about how you use manual therapy to create safety and how perhaps, it may not be the specificity of the stretch, mobility or strength exercise that you prescribe, but how that movement can provide a person with a way to move with less anticipation of threat?
