Closed/Previous Studies 2012-2019
There have been ten non-commercial studies so far that have previously used Registry data or have been supported by the Network. In addition, a commercial study has previously been granted approval to access Registry data. A brief summary of each non-commercial study is listed below, but please note that all are now closed to recruitment.
- Investigating the brain networks underlying altered body perceptions and related pain (sponsored by the University of the West of England) - this study is funded by Versus Arthritis and builds on work previously undertaken as part of MIRAGE. The purpose of the study is to find out more about the brain activity when someone is experiencing a visual illusion and how different regions of the brain communicate with each other. People with CRPS or hand osteoarthritis, along with health volunteers, have been recruited to compare the brain activity of people in pain to those without pain. This will enable further investigation of how differences in the brain networks are related to alterations in the way that pain patients perceive their affected limb
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- CRPS PRISMA Trial: Pain Reduction by Inducing Sensory-Motor Adaptation (sponsored by the University of Bath) - people with CRPS can have difficulty attending to their affected limb(s). 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. 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 several other factors that could have influenced people's pain. Therefore, the researchers conducted a robust test of prism adaptation for upper limb CRPS, called a double-blind randomised 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. The 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 the researchers 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)
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- Why people with CRPS perceive their affected limb differently - 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. Researchers at the University of Bath were interested in understanding why the feelings that a CRPS-affected limb is an unusual shape or size seems to persist rather than go back to normal. They 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. They expected to find that people with CRPS would be less likely to update their perception of their body during this task, but in fact they found the opposite: they 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
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- Bodily changes and sensory sensitivity in CRPS and fibromyalgia - part of the diagnostic criteria of CRPS and fibromyalgia is that the person is more sensitive to pain and touch. However, some people with these conditions 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 these kind of changes, researchers at the University of Bath wanted to find out how common they are in these groups compared to people with other pain condition and people without pain. They 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 asked about were reported by at least some people without chronic pain, so all the changes are within the normal experience. Compared to the other groups, 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 weren't 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, the results show that people with 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 were asked about, it is clear that these changes are not experienced by all people with CRPS or fibromyalgia
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- Cortical Reorganisation (CoRe) Study (sponsored by Cambridge University Hospitals NHS Foundation Trust and the University of Cambridge) - some research studies have previously found subtle changes in the structure and function of the brain in CRPS. Many people with CRPS also have difficulties in accurately perceiving sensations from the body, but it is unknown whether this is related to brain changes. The CoRe study investigated these brain changes, to determine whether there is a link with the inability to perceive body sensations accurately. The study was a collaboration between the University of Cambridge and the University of Liverpool. People with CRPS who were recruited into the study were asked to complete questionnaires to assess their level of pain, function and mood. They also had clinical tests to measure body perceptions, brain activity (EEG), and brain structure (MRI scan). Different fingers were buzzed hundreds of times, but with repeating patterns. Participants were asked to record which fingers were being touched. The time and accuracy improved as the patterns were predicted by the participants. However, people with CRPS were shown to find it difficult to learn the patterns and their responses improved more slowly than would be predicted by the healthy volunteer control data. This suggests that the difficulty that some people with CRPS have in recognising their fingers with their eyes closed is caused by 'top down' neural networks rather than 'bottom up' peripheral inputs. This work was funded by an award from the prestigious International Annual Grunenthal EGG programme and is due to be published in the leading journal PAIN
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- Genetic Pain Study (sponsored by Cambridge University Hospitals NHS Foundation Trust and the University of Cambridge) - the study team wished to understand the genetics of patients with chronic pain that is difficult to treat or explain, with the aim of identifying further genes that strongly influence the amount of pain a person feels. The discovery of any new genes whose function is not affected by currently available drugs could lead to the development of new treatments. The researchers recruited patients with chronic pain disorders for whom current medical treatments have not provided a complete solution to their pain. All patients who were suitable were asked to donate a salivary for genetic analyses and complete an assessment that characterises their chronic pain through self-reported questionnaires
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- MIRAGE Study - this studied the effectiveness of viewing visual illusions that alter the size and shape of the painful hand to provide pain relief for people with CRPS. Virtual reality was used by the MIRAGE system to create an image of how the patient desired their affected hand to look like. The study aimed to determine whether repeated exposure to the illusion was effective in sustaining pain relief and reducing body perception disturbance, but also to determine whether visually manipulating the affected hand improved movement performance and reduced the fear of movement. Results of the study have been analysed and it is hoped that a research paper will be published in due course
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- LIPs Trial Study - this was a randomised controlled trial to explore the effectiveness of low dose Intravenous Immunoglobulin (IVIg) therapy in reducing pain in patients with moderate to severe CRPS. It was led by Dr Andreas Goebel (Consultant in Pain Medicine, Walton Centre NHS Trust in Liverpool). This study recruited patients across seven specialist pain centres in England and Scotland
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- Core Outcome Measurement set for complex regional PAin syndrome Clinical sTudies (COMPACT) (sponsored by the Royal United Hospitals Bath NHS Foundation Trust) - an international team of patients, clinicians and researchers was established in 2013. The aim of this study was to agree on a minimum core set of outcome measures which will be recommended for use in all CRPS clinical studies. The development of a core measurement set would make it easier to compare data to answer specific research questions agreed as internationally important and relevant for the advance of the treatment of CRPS. The core measurement set (COMPACT) was agreed through a series of workshops and uses a number of patient-reported questionnaires to assess many aspects of CRPS. One clinician reported outcome measure captures the degree of severity of CRPS. The initial recommendations were published in 2017
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- CRPS International Recovery Study (sponsored by the Reflex Sympathetic Dystrophy Syndrome Association, RSDSA) - this included an international team of clinical researchers looking to define recovery from CRPS and the priorities of recovery, from the perspective of the patient’s point of view. The study ran from 2012-2015 with the aim of helping healthcare professionals understand what is important from the patient’s perspective, in terms of treatment outcomes. The study was led by Professor Candy McCabe in collaboration with colleagues from Europe and North America. Please click HERE to read an article that gives an overview of the CRPS Recovery Study and its findings