European journal of pain : EJP
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Comparative Study
Pain and other symptoms of CRPS can be increased by ambiguous visual stimuli--an exploratory study.
Visual disturbance, visuo-spatial difficulties, and exacerbations of pain associated with these, have been reported by some patients with Complex Regional Pain Syndrome (CRPS). ⋯ It is possible to worsen the pain suffered in CRPS, and to produce other somatic sensations, by means of a visual stimulus alone. This is a newly described finding. As a clinical and research tool, the experimental method provides a means to generate and exacerbate somaesthetic disturbances, including pain, without moving the affected limb and causing nociceptive interference. This may be particularly useful for brain imaging studies.
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Randomized Controlled Trial Comparative Study
Pain relief by applying transcutaneous electrical nerve stimulation (TENS) during unsedated colonoscopy: a randomized double-blind placebo-controlled trial.
Transcutaneous electrical nerve stimulation (TENS) is a noninvasive alternative to traditional pain treatments. TENS has been studied in the past as a pain reduction modality in colonoscopy with limited success. Reviews and meta-analysis have shown that the inconclusive results of TENS may be due to the lack of randomized controlled trials and the difficulty in defining precise output parameters. ⋯ On the five-point Likert scale, there was also a significant reduction in pain score in the active TENS group compared to the placebo TENS and control groups (P=0.009). No significant differences were found between the study groups as to the bloating sensation and the duration of the procedure. We conclude that TENS can be used as a pain relief therapy in unsedated screening colonoscopy.
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Randomized Controlled Trial
Internal validity of inter-digital web pinching as a model for perceptual diffuse noxious inhibitory controls-induced hypoalgesia in healthy humans.
Hot and ice-water immersions are commonly used for heterotopic noxious counter-stimulation (HNCS) in investigations on endogenous pain modulation. However, coincident sympathetic thermoregulatory activity does not allow to differentiate between perceptual hypoalgesia related to baroreflex sensitivity (BRS) or diffuse noxious inhibitory controls (DNIC). The present study analysed the internal validity of another supposedly less confounded tonic pain model (inter-digital web pinching; IWP) regarding its potential as DNIC trigger. ⋯ Regardless of pain modality, wind-up was significantly reduced by HNCS, although this was stronger for painful water immersion than for noxious pinching (P<0.01). The HNCS types allow a differentiation between BRS-related and DNIC-like hypoalgesia. IWP proved its validity for DNIC induction, being practically non-confounded by BRS.
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Pressure algometry is widely used to assess deep tissue sensitivity. In this study the relation between pressure-induced pain in humans and stress/strain distribution within the deep tissue is evaluated. A three-dimensional finite-element computer model was used to describe the stress/strain distribution in tissues of the lower leg during pressure stimulation. ⋯ The human pressure pain thresholds with the rounded probe were significantly lower compared with the flat probe (p<0.05). The results suggest that pressure-induced muscle pain is mainly related to muscle strain and most efficiently induced by large rounded probes, while smaller and flat ones mainly activate superficial structures. The relatively low stress in the deep tissue suggests that the mechanosensitivity of nociceptors in the deep tissue is lower compared with nociceptors in the superficial tissue.
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Randomized Controlled Trial
Effects of treatment of peripheral pain generators in fibromyalgia patients.
Fibromyalgia syndrome (FS) frequently co-occurs with regional pain disorders. This study evaluated how these disorders contribute to FS, by assessing effects of local active vs placebo treatment of muscle/joint pain sources on FS symptoms. Female patients with (1) FS+myofascial pain syndromes from trigger points (n=68), or (2) FS+joint pain (n=56) underwent evaluation of myofascial/joint symptoms [number/intensity of pain episodes, pressure pain thresholds at trigger/joint site, paracetamol consumption] and FS symptoms [pain intensity, pressure pain thresholds at tender points, pressure and electrical pain thresholds in skin, subcutis and muscle in a non-painful site]. ⋯ At day 8, all placebo-treated patients requested active local therapy (days 8 and 11) vs only three patients under active treatment. At a 3-week follow-up, FS pain was still lower than basis in patients not undergoing further therapy and had decreased in those undergoing active therapy from day 8 (p<0.0001). Localized muscle/joint pains impact significantly on FS, probably through increased central sensitization by the peripheral input; their systematic identification and treatment are recommended in fibromyalgia.