So, I headed up to the Science Museum in London last week to see the “Pain Less” exhibition, cos I can do that now, finally (see “memory, forgetting and chronic pain” post). The exhibition consists of a series of stands documenting current research into the psychology of pain, the use of technology to investigate, document and treat pain and research into pain receptors in order to provide new pain blocking pharmaceuticals.
First thing that struck me were the statistics, 1 in 5 people live with persistent chronic pain, so where are they all? The only people I have encountered were those on my pain management course. It was a striking indicator of the silence surrounding pain, and it’s invisibility. I hide when in a lot of pain, retreat, am afraid to speak of it to new people in my life. It courses it’s way through our bodies and creates additional ‘noise’ in our heads and yet it’s never heard outside of ourselves. But perhaps technology could lead on that one, the exhibition begins by taking a look at brain scans, specifically at how MRI scanners now show that certain parts of the brain are activated when we’re in pain. So, it’s not ‘just in our heads’ after all, it’s in our brains.
I’ll start with the psychology side of things, as that’s where my interest lies currently. Irene Tracey, pain neuroscientist http://www.neuroethics.ox.ac.uk/our_members/irene_tracey talks about how “pain is both a sensory and emotional experience” and this part of the display focuses on our perception of pain and how that impacts on how it makes us feel. She states that pain is affected by environmental factors in addition to physical ones, i.e. sound and temperature, our thoughts, beliefs, feelings and attitudes. Sound is an interesting one, I experience that myself, a sound can resonate through my body as pain and I’ve never heard that from anyone else before. And Irene says they can show conclusively in MRI scans that feeling negative or depressed increases the brain’s response to pain. Her approach to treatment is a combination of drugs, physical rehabilitation and psychology, very much my approach right now.
Paul Enck, psychologist, with a particular interest in placebos, states that our thoughts and expectations really can change the way that we respond to treatment, even to the extent that we can feel negative side effects if we think we’re going to….and I have to quote my mother on this one, who recently exclaimed, in all seriousness: “I have every single symptom listed in the side-effects leaflet”! Our expectations or anticipation of pain also has an effect on how we may experience it. Looking at how we might change our perceptual experience of pain, Postdoctoral Research Fellow, Fedel Zeidan http://www.wakehealth.edu/Research/Neurobiology-and-Anatomy/Fadel-Zeidan,-PhD.htm experiments with meditation as a form of pain control: “In one of my experiments healthy volunteers were given a painful stimulus and rated their experience. After 4 sessions of meditation training, meditating whilst experiencing the painful stimulation reduced pain unpleasantness by 57% and pain intensity by 40%. In contrast, researchers have found that a clinical dose of morphine reduces pain by up to 25%.” Impressive and encouraging stats those, however, I also remember a clinical trial in which participants were asked to put their hand into a bucket of ice. Those who were told that they could take it out again very soon were able to tolerate the discomfort for much longer than those who were told it would need to remain in there for a long period of time. This makes me wonder how an expectation of pain based on repeated experience of prolonged and persistent pain could be assessed in a similar way. I imagine many of the participants in these studies do not actually experience persistent pain. It’s an additional challenge to make a chronic pain patient believe that even a dent can be made in their pain, as their prior experience is so deeply ingrained. I find it a constant struggle to try reset this brain of mine, it almost always wants to revert to a seemingly ‘default’ pain position. So complex all this, there are so many factors.
There is also a section dealing with phantom limb pain, a phenomenon whereby an amputee still feels pain in the limb which has been removed, it’s remarkably common, apparently it affects between 60-80% of amputees. It’s an example often used to demonstrate how pain is not necessarily indicative of actual injury or tissue damage but a series of mistaken signals in the brain. Famous neuroscientist Vilayanur Ramachandran developed a technique using a mirror box to try to re-configure the body/brain map of an amputee by showing them a mirror image of their moving arm, so that the brain could actually conceptualise movement in the missing limb http://blog.ted.com/2007/10/23/vilayanur_ramac/. In this exhibition researchers Steve Pettifer and Ilan Lieberman show how Virtual Reality can also help to re-configure the brain. Using vuzix iwear, an xbox 360 and a gyroscope sensor, the subject waves his phantom limb, sending messages to the brain that it is actually active and not damaged. This particular subject said that he benefited from 2 days pain relief from one VR session.
We next see a case study of a man who does not feel pain at all, which in itself is extremely dangerous. Apparently mutation to the SCN9A gene makes the body not experience pain, so scientists are working to see if other receptors can be isolated to block pain signals. Now the way that this works is (let me see if I can get this right!) our nociceptors respond to pain source and create electrical signals using proteins called sodium channels, these charged sodium ions change the electrical charge of the nerve and carry it up the spinal cord to alert the brain to pain. There are 9 sodium channels but ‘Nav 1.7’ is the one for carrying pain signals, each channel has it’s own gene, and the gene for channel Nav 1.7 is called SCN9A. (Phew!) “Mutation to this gene can affect how you experience pain. Some can make people super-sensitive to pain, while other mutations can cause people to feel no physical pain at all…….If scientists can isolate a molecule that can block pain signals in some way, they will have a powerful painkiller”. Researchers have found molecules in toxic venom from snails, snakes, scorpions and spiders that can block human sodium channels, therefore they are looking for a venom component that blocks pain channel Nav 1.7. They are not selective enough yet, and they block other channels too, so there’s a way to go yet, explains Glenn King, Professor of University of Queensland. Julie Keeble, Kings College London is researching another type of pain transmitter called TRP (transient receptor potential) and is looking at mustard oil and chilli pepper as a potential source of pain relief in arthritis patients.
In addition to all this, there is a film entitled “Visualising Pain” by a group of chronic pain patients, describing their experiences using visual metaphors. The one that resonated with me was a hall of mirrors, which shows the impact it has on our changed sense of identity, but also on repeat reflections which morph and change, reflecting continually back on themselves and us, creating a fluid and ungraspable experience. I came away from this show realising that we are still in the dark about pain, that clearly there is some fascinating research, but that on a personal level perhaps I am wasting my time trying to understand, intellectually, what is going on in my body. I’m still undecided on that one. If the experts can’t work it all out then what the hell do I think I’m trying to achieve here? Why do I need to ‘know’ still, what is causing my pain? Does it matter? Interestingly my pain levels shot up too, pain immersion clearly set those nociceptors of mine off! Writing this up however has given me a timely reminder to be very aware of my expectation and anticipation of pain. I am about to embark on a series of journeys that are going to really test me, so, it’s upped my game somewhat for all that’s to come, and that’s got to be good right?
The exhibition is on until Saturday 31 August, for more information about the exhibition go to their blog http://painlessexhibition.wordpress.com/.