Pain that occurs after major trauma like the head injury your sustained that lasts indefinitely is labeled chronic. This type of pain has been the focus of neuroimaging studies for the last two decades. Neuroimaging has opened our eyes to the changes in the brain that accompany chronic pain. Changes that affect the anatomy, biochemistry, and neurochemistry of the nervous system.
These techniques have made it possible to study the brains of patients with chronic pain compared to individuals without pain. Measuring density of brain tissue, connections between brain structures, brain biochemistry, and location and type of neurotransmitters and their receptors has helped explain more about central pain processing. Central pain processing refers to how pain is processed in the central nervous system (brain and spinal cord).
Clearly the brain is altered in patients with chronic pain. It’s these measurable physiologic changes that define chronic pain as a disease rather than a syndrome. The medical definition of disease is any disorder of structure or function in a human, animal, or plant; especially one that produces specific symptoms. A syndrome is more of a collection of signs and symptoms not always with an identifiable organic cause.
With observable changes in the brain, it makes sense to think that the disordered brain function could be considered a disease. But there are other experts who disagree because it’s not always clear which came first: the pain or the brain changes? Scientists are focused now on unraveling this question with the hope of finding more effective (and permanently successful) ways to treat people like your brother who suffers from a chronic pain condition with no end in sight and poor quality of life as a result.