Axel Vittersø’s Research On Why People With CRPS Perceive Their Affected Limb Differently
Over the past year Dr Janet Bultitude and her group at the Centre for Pain Research at the University of Bath have finished data collection for three studies that recruited participants with the help of CRPS UK. Summaries of the main findings are provided below:
Axel Vittersø’s Research On Why People With CRPS Perceive Their Affected Limb Differently
With collaborators Gavin Buckingham, Monika Halicka, Michael J Proulx and Janet H Bultitude
Many people with CRPS experience that the shape and size of parts of their body feel different to their actual size. These altered perceptions seem to be related to pain and other symptoms of CRPS. However, we know that about two-thirds of people whose arm or leg is immobilised in a plaster cast initially experience unusual perceptions of this body part, but that this changes back after the plaster cast is removed. Even in people without pain, the way we experience the size and shape of our body parts is very flexible, for example, allowing us to feel as though a tool like a tennis racket has become ‘part of our body’. We were interested in understanding why the feelings that an affected limb is an unusual shape or size seems to persist in people with cRPS rather than go back to normal. We tested this by asking people with and without CRPS to use some golf-club-like tools with their hands, and by using sensory tests that indicate how the arms are perceived. We expected to find that people with CRPS would be less likely to update their perception of their body during this task, but in fact we found the opposite: we found that the perceived size of the arms was more likely to change for people with CRPS than for people without any pain. This could suggest that the perception of the body is less stable in people with CRPS. This is good news, because knowing that body perception can change in people with CRPS supports the use of therapies that aim to help people with the condition work towards finding normal sensations in their affected limbs.
Bodily changes and sensory sensitivity in CRPS and fibromyalgia
Research by Antonia F ten Brink, Louisa Peters, Vivianna Kompouli, Abbie Jordan, Candida S McCabe, Andreas Goebel, and Janet H Bultitude
Part of the diagnostic criteria of CRPS and fibromyalgia is that the person is more sensitive to pain and touch. However, some people with CRPS or fibromyalgia tell us that they are more sensitive to other things as well, such as loud noises and bright lights. Some also mention bodily changes such as food intolerance, or bowel and bladder symptoms. Since not all people with CRPS or fibromyalgia report additional bodily and sensory changes like these, we wanted to find out how common they are in these groups compared to people with other pain conditions and people without pain.
We asked 390 people with CRPS, 425 with fibromyalgia, 311 with other chronic pain conditions, and 441 pain-free controls to fill out a survey with questions on the symptoms of the disorders, sensory sensitivity, and bodily changes. One important finding is that all of the sensory and bodily changes that we asked about were reported by at least some people without chronic pain, which tells us that they are within the normal experience and not JUST experienced by people with pain. Compared to the other groups, however, people with CRPS and/or fibromyalgia were more likely than the other groups to report changes in their ability to move their body or parts of their body, and in biological responses such as sweating or feeling unusually cold. They were also more likely to report that environmental factors such as bright lights, loud noises, or weather caused them pain, discomfort, or distress. People with fibromyalgia specifically mentioned that they had experienced changes in vision and hearing, urinary/intestinal function, and drinking and eating since their diagnosis; but these were not reported by people with CRPS any more frequently than people in the other groups. In contrast, people with CRPS were more likely to mention changes related to hair, skin, and nails; and to infection and healing of their skin.
Overall, our results show that people with CRPS and/or fibromyalgia do report some bodily and sensory changes more often than people with other pain conditions and without pain. There is some overlap between CRPS and fibromyalgia, but most likely different mechanisms are at play. Furthermore, since only a proportion of people in each group reported the changes that we asked about, it is clear that these changes are not experienced by all people with CRPS or fibromyalgia.
Monika Halicka’s CRPS PRISMA Trial: Pain Reduction by Inducing Sensory-Motor Adaptation
With collaborators Axel D Vittersø, Hayley McCullough, Andreas Goebel, Leila Heelas, Michael J Proulx, and Janet H Bultitude
People with CRPS can have difficulty attending to their affected limb(s), and there is some evidence that this is related to pain and other physical symptoms. Prism adaptation can reduce similar problems with attention in people with other conditions. The treatment involves doing a pointing task with one hand while wearing prism goggles that shift what we see to one side. Our brain learns to adapt the pointing movements towards the affected side, and attention should follow. Prism adaptation was found to reduce upper limb CRPS pain in previous studies, however these studies involved only small numbers of participants and did not control for several other factors that could have influenced people’s pain. Therefore, we conducted a robust test of prism adaptation for upper limb CRPS, called a double-blind randomized controlled trial, in which half of the people underwent real treatment and half underwent control treatment. Neither the participants nor the researcher who tested their symptoms knew what treatment each patient received. Our trial involved 49 people with CRPS and showed that two weeks of prism adaptation did not reduce pain or CRPS symptom severity more than the control treatment. In fact, CRPS severity decreased in both treatment groups. This could be due to the ‘placebo effect’. Another possibility is that symptoms were reduced by both treatments because of the movements of the affected arm, which were done by all participants. Although this is not the result that we were hoping for, having tested prism adaptation treatment in a well-controlled way and found that it doesn’t appear to be effective means that researchers and clinicians can turn their attention to investigating other treatments. This research was supported by the Reflex Sympathetic Dystrophy Syndrome Association (RSDSA), and Monika Halicka presented the results at the 5th Annual National CRPS Conference in Bristol, 2019.
Updated: 02/12/2019