Chronic Pain, Central Sensitization and Physical Therapy
How your brain can trick you into thinking you're in pain.
Posted November 10, 2020
This blog post was written with contributions by Jamie Pribyl, DPT.
Chronic pain is a condition in the nervous system where a light switch seemingly got turned on and never got turned off. Patients initially experience pain because of some type of injury that has occurred (i.e. noxious stimuli). This is nature's way of helping us protect ourselves from further injury. The pain typically stops once the noxious stimuli have discontinued and enough time has passed for the injury to heal itself. Chronic pain occurs when patients continue to experience pain even though the noxious stimuli have stopped and the injury has healed with time.
Central sensitization is a chronic pain condition where the brain rewires itself to maintain a persistent state of high reactivity. This condition starts after an initial injury has healed, but the pain signals continue to be active. This heightened state of sensitivity lowers the threshold for pain, making stimulus as simple as touch uncomfortable to unbearable.
The pain that patients experience with both conditions is very real. It is particularly hard to treat because there is not an ongoing noxious stimulus that is triggering the pain. This makes it difficult for patients to understand why they have persistent pain which leads to pain catastrophizing, activity interference, and fear-avoidance. All of these issues need to be addressed in order to help the patient. Providers who use the biopsychosocial model typically have good success in treating these cases. Providers can utilize medications to turn down the pain signal, employ cognitive behavioral therapy techniques to help the patient understand that no further tissue damage is occurring and physical therapy can get these patients moving and active once again.
It is important for providers to incorporate physical therapy to help chronic pain and central sensitization. The task is to use mild exercise to get the patient to start mobilizing the body part that is affected. Slowly gaining mobility can restart the misfiring pain signals and bring the functionality back to "normal." This is where physical therapy can make a substantial difference in the patient’s recovery.
An example is mirror therapy which has been shown to help patients with phantom limb pain. The patient is placed perpendicular to the front of a mirror, where the reflective side faces the uninjured side. The patient will then move the uninjured extremity which the brain perceives as a movement in the injured body part. The hypervigilant nervous system begins to relax as it witnesses non-threatening movement in the injured extremity, even though it is not moving. This visual recreation has shown statistically to significantly reduce pain. Furthermore, it begins to heal the misfiring neurons sending pain signals to the brain.
One of the most important things in dealing with chronic pain and central sensitization is remembering that the changes that occurred to lead to this condition can equally be unlearned. You can begin to reinterpret your pain, start to mobilize your injured body part, and over time regain your previous functionality. It’s all about movement and a commitment to healing.