Syndrome douloureux régional complexe

Le syndrome douloureux régional complexe (SDRC) est un état pathologique caractérisé par un syndrome associant des douleurs et d'autres symptômes touchant typiquement une extrémité après un traumatisme ou une intervention chirurgicale même minime. Ce syndrome pourrait être dû à des causes neurologiques, notamment une dysfonction des fibres de petit calibre des nerfs périphériques - qui protègent des stimulations douloureuses et thermiques et/ou de grand calibre qui détectent les stimulations tactiles. Classification et synonymes Cette maladie comporte deux sous-types: SDRC- (dystrophie sympathique réflexe) et SDRC- (causalgie) selon respectivement l'absence ou l'existence d'une atteinte nerveuse. On trouve plusieurs noms pour la décrire :

syndrome de Sudeck-Leriche ou maladie de Sudeck (1866-1945) qui le premier l'a décrite ;
algodystrophie ou algoneurodystrophie ;
causalgie, décrite par Weir Mitchell en 1872 (traduction française en 1874) dans le cadre de certaines

Cognitive neuroprosthetics for investigating and restoring body perception

Marco Solcà

Our brain constantly receives and integrates a flow of multisensory bodily inputs that are responsible for the way our body is represented and consciously experienced. However, in some pathological conditions, patients might experience altered perceptions of their body or suffer from abnormal bodily sensations such as chronic pain. Recent studies in cognitive neuroscience demonstrate that it is possible to modulate bodily self-consciousness and related bodily experiences by experimentally manipulating multisensory bodily inputs. Using such approaches, this work aims to investigate abnormal body experiences and to develop new therapeutic solutions for patients suffering from distorted body representation and chronic pain. First, we manipulated visuo-tactile information to investigate alterations of bodily self-consciousness in spinal cord injured patients and demonstrated the potential analgesic effects of such multisensory stimulation (Study 1). Then, we combined neuro-tactile stimulation with visual stimulation via virtual reality in amputees to induce embodiment for their prosthetic hands, and to improve abnormal phantom limb perceptions (Study 2). We then used a similar approach in patients with chronic leg pain and combined spinal cord stimulation with visual stimulation via virtual reality to in-crease analgesia induced by neuromodulation (Study 3). In another series of studies, we investigated the role of inter-oceptive signals in chronic pain. First, we demonstrated that patients suffering from complex regional pain syndrome (CRPS) had reduced abilities in perceiving and processing their heartbeat (Study 4). Then, we manipulated interocep-tive information with visual stimulation via virtual reality to reduced CRPS symptoms (Study 5). Collectively, these five studies demonstrate the possibility to use the latest research on the neuroscience of embodi-ment and virtual technology to study disorders of body representation. Furthermore we aim to develop new cognitive neuroprosthetic approaches including restoring normal body perception, inducing embodiment for a prosthetic limb, and alleviating chronic pain.

EPFL2019

Heartbeat-enhanced immersive virtual reality to treat complex regional pain syndrome

Javier Bello Ruiz, Olaf Blanke, Bruno Herbelin, Roberta Ronchi, Thomas Schmidlin, Andrea Serino, Marco Solcà

OBJECTIVES: To develop and test a new immersive digital technology for complex regional pain syndrome (CRPS) that combines principles from mirror therapy and immersive virtual reality and the latest research from multisensory body processing. METHODS: In this crossover double-blind study, 24 patients with CRPS and 24 age- and sex-matched healthy controls were immersed in a virtual environment and shown a virtual depiction of their affected limb that was flashing in synchrony (or in asynchrony in the control condition) with their own online detected heartbeat (heartbeat-enhanced virtual reality [HEVR]). The primary outcome measures for pain reduction were subjective pain ratings, force strength, and heart rate variability (HRV). RESULTS: HEVR reduced pain ratings, improved motor limb function, and modulated a physiologic pain marker (HRV). These significant improvements were reliable and highly selective, absent in control HEVR conditions, not observed in healthy controls, and obtained without the application of tactile stimulation (or movement) of the painful limb, using a readily available biological signal (the heartbeat) that is most often not consciously perceived (thus preventing placebo effects). CONCLUSIONS: Next to these specific and well-controlled analgesic effects, immersive HEVR allows the application of prolonged and repeated doses of digital therapy, enables the automatized integration with existing pain treatments, and avoids application of painful bodily cues while minimizing the active involvement of the patient and therapist. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that HEVR reduces pain and increases force strength in patients with CRPS.

2018

Pain reduction due to novel sensory-motor training in Complex Regional Pain Syndrome I – A pilot study

Friedhelm Christoph Hummel, Anne-Christine Schmid

Background and aims Patients suffering from Complex Regional Pain Syndrome (CRPS) of the upper limb show a changed cortical representation of the affected hand. The lip area invades the former hand area contralateral to the affected hand. This change in cortical representation is correlated to the intensity of ongoing pain in patients with CRPS. Further studies revealed that restoration of the original representation coincides with a decrease of pain. Sensory-motor training protocols can increase and/or relocate cortical somatosensory and motor representation areas of the fingers, as shown, for example, in Braille reading individuals and professional violin players. Further, there is evidence that sensory-motor discrimination training has a beneficial effect on both the intensity of pain and the mislocalization of sensory-motor cortical areas in CRPS patients. Based on these propositions, we developed a novel sensory-motor self-training paradigm for CRPS patients to use in a home-based manner. Methods Ten CRPS patients performed the sensory-motor training for 2 weeks. The training consists of a braille-like haptic task with different training modes (bi-manual, speed and memory training). During the training, as well as 1 week before and after, patients were asked to fill out pain diaries. Furthermore, measures of impairment were acquired at baseline and post training. Results Patients showed significant pain reduction after the 2 week training period. The overall disability as well as the depression scores showed a trend to improve after the 2 week training. The reduction in pain was correlated with the total amount of training performed. Conclusions This is a first proof of principle study of a novel sensory-motor self-training protocol to reduce pain in CRPS patients. The more consistent the patients trained the larger the pain reduction. Sensory-motor training, which can be performed on a regular basis at home might provide a novel interventional strategy to improve symptoms of CRPS. Implications Although a larger study needs to be conducted to confirm our findings, including long-term follow-up, the results show, that a sensory-motor home-based training is a strategy worth exploring further for the reduction of pain as well as high frequency training for patients with CRPS.

Elsevier Science Bv2017