Limb position awareness is challenged in both arms of patients with complex regional pain syndrome (CRPS) even when only one arm has the CRPS. This phenomenon points to the possibility of what is called central processing errors. Central processing refers to the natural function of the nervous system (nerves, spinal cord, brain).
In the case of CRPS, errors occur in the nervous system’s ability to keep track of all body parts at any given time. A recent study published by researchers from England and New Zealand have shown that patients with this condition have a problem with general awareness of limb position. When one side is affected, both limbs respond as if they no longer know where they are in relation to the body or moving through space.
Many patients with complex regional pain syndrome have a mental picture of the affected arm that includes some distortion. For example, when they look at the arm, part of it is missing or a finger is oddly shaped. Some patients describe the arm as much larger than it actually is.
Having pain anywhere in the affected arm does not help patient find the arm. Being able to see the arm does help. Hand therapists who work with patients who have complex regional pain syndrome are beginning to use mirrors to help re-map the brain’s own image of the body. This is one way it may be possible to restore normal reach and function of limbs affected by this condition.