So what is Chronic Pain Syndrome anyway? It is a question I’ve been asking myself and the professionals for some time. It’s complex, I rarely get a satisfactory answer from professionals hence my own investigation. Sometimes chronic pain comes on as the result of an injury, and sometimes it just comes out of nowhere. It is considered a ‘chronic’ condition when the pain has persisted beyond six months, as this is the time it takes for most injuries to heal. With chronic pain though, the pain does not go away when the tissues heal as the central nervous system has become hypersensitive, misinterpreting normal messages as pain and amplifying it, it’s like the volume is constantly turned up. At this stage it has become a disease of the nervous system via a process of cortical reorganisation in the brain.
Let’s take it from the beginning, as I understand it anyway. In the case of an injury (as in my particular case), the healing process often involves inflammation of the area making a ‘chemical soup’ which then creates changes in the central nervous system. This is how the central nervous system can become oversensitised, and in the case of chronic pain, it seems to stay this way, in some cases it gets worse, particularly if, as a result of pain you become less active, as this can create additional muscle tension, immobilty, sometimes leading to depression which then exacerbates the patient’ s experience of pain. Previously innocuous stimuli such as touch, vibration, even noise, can become a source of pain. Essentially it’s a ‘signalling problem’ between the spinal cord and the brain and the longer that pain persists the more sensitive the nociceptive system in the spinal column can become, alerting the brain to pain stimuli more frequently. These signals, over time, create patterns, become hard-wired into the brain and are therefore very difficult to reverse. There is also evidence to suggest that nerves can actually grow more receptors so that more and more messages can be received and relayed to the brain. I attended St Thomas’s residential pain management programme about four years ago http://www.guysandstthomas.nhs.uk/our-services/pain/input/patients/input-programme.aspx and Vicky Harding, the physiotherapist there has put this document together: “Pain, the Nerves and the Brain” which I think explains the condition very well http://www.ppip.org.uk/Documents
I’m currently attending a series of Open Lectures at my local University delivered by the Cognitive Science department which is helping me to develop my understanding of the functionality of the brain. In a lecture entitled “Consciousness and the Brain” the idea of ‘chunking’ was introduced, it is the way that the brain processes information and learns new material. The brain has a ravenous appetite for pattern which it latches onto tightly once found. Look at our interest in crosswords, puzzles, games, and think about how we form habits so naturally without even thinking, always sitting in the same chair for instance, walking the same way home from work every day. In design it is well established that repetitive motifs induce a feeling of comfort in a viewer, this is a technique used by designers all the time, I could go on, my point is, this pattern-seeking seems to be a default setting. I also went to a talk by the co-director of Sackler Centre for Consciousness Science, Anil Seth http://www.anilseth.com/ where there was some discussion at the Q&A about the development of Artificial Intelligence and computational brain modelling. Anil confirmed that there actually was a possibility for the brain to be artificially ‘modelled’ in this way, as prediction is such a strong component in the brain, i.e. it ‘computes’ by trawling through previous data to come up with a prediction for any particular scenario. In relation to pain messages this makes perfect sense, the brain predicts that the body will be in pain in certain situations because it has experienced this before over and over, therefore repeatedly emitting mistaken pain signals sometimes even without any sensory cue, and it latches onto this as it has such an appetite for pattern formation. So, it’s no wonder it is so hard to ‘shift’ the default pain position in our brains.
This all sounds a bit grim I know but I’m not done, this video lightens the topic (moderately). It’s a talk by Professor Lorimer Moseley of University of South Australia entitiled “Pain. Is it all just in your mind?” http://www.youtube.com/watch?v=-3NmTE-fJSo&feature=share yeah, it’s kind of long but he’s a wonderful and funny speaker so its not a chore. He uses visual illusions, his own personal experience and scientific studies to illustrate how our brains misinterpret information in a way which is out of our control. He shows how the brain uses a combination of sensory cues, prior experience, anticipated consequences and information from spinal nociceptors to switch on connections between the neurons which then relay pain signals without our volition. It is important for us to understand this, as there is often stigma attached to having persistent pain, and consequently a sense of shame for not just being able to ‘get over it’, this clearly adds to the overall distress. The understanding that these signals are sent outside of our conscious awareness has been fundamental to my own acceptance of the condition, that it is ‘not my fault’ has lifted an enormous weight from my mind and interestingly he states just that, that understanding these factors is key to rehabilitation. So no, the pain is not all in your mind, it is all in your brain, a very difficult region to access, difficult but not, as I have recently discovered, impossible. And that’s where we get onto the subject of neuroplasticity.