Articles: hyperalgesia.
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The purpose of this systematic review was to summarize and critically appraise the results of 10 years of human laboratory research on pain and sex/gender. An electronic search strategy was designed by a medical librarian and conducted in multiple databases. A total of 172 articles published between 1998 and 2008 were retrieved, analyzed, and synthesized. ⋯ The majority of the studies that measured pain intensity and unpleasantness showed no sex difference in many pain modalities. In summary, 10 years of laboratory research have not been successful in producing a clear and consistent pattern of sex differences in human pain sensitivity, even with the use of deep, tonic, long-lasting stimuli, which are known to better mimic clinical pain. Whether laboratory studies in healthy subjects are the best paradigm to investigate sex differences in pain perception is open to question and should be discussed with a view to enhancing the clinical relevance of these experiments and developing new research avenues.
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Randomized Controlled Trial Comparative Study
A comparison of the hypoalgesic effects of transcutaneous electrical nerve stimulation (TENS) and non-invasive interactive neurostimulation (InterX(®)) on experimentally induced blunt pressure pain using healthy human volunteers.
Non-invasive interactive neurostimulation (InterX(®)) delivers high amplitude electrical pulsed currents at points of low impedance on the skin. This study compared the hypoalgesic effect of non-invasive interactive neurostimulation with transcutaneous electrical nerve stimulation (TENS). ⋯ Given the limited power of this study, we show that there were no significant differences in hypoalgesia between non-invasive interactive neurostimulation and TENS. Unlike our previous studies we also failed to detect a change pain threshold during TENS. Nevertheless, our findings can be used to inform the design of an appropriately powered study on pain patients.
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Curr Opin Support Palliat Care · Mar 2012
ReviewVisceral pain: the ins and outs, the ups and downs.
Visceral pain represents a major clinical problem, yet far less is known about its mechanisms compared with somatic pains, for example, from cutaneous and muscular structures. ⋯ This review should inform on the recognition of what occurs in patients with visceral pain, why comorbidities are common and how analgesic treatments work.
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Whiplash-associated disorders (WAD) have been associated with sensory disturbances such as hypersensitivity or hypoesthesia. Different psychological factors seem to be important for prognosis and symptom presentation in WAD. Multivariate correlations between pain thresholds for pressure (PPT), cold and heat (CPT, HPT), detection thresholds for cold and warmth, pain intensity variables, and psychological aspects in women with chronic WAD (n=28) and in healthy pain-free controls (n=29) were investigated. ⋯ Pain intensity aspects were generally the strongest predictors of PPT in WAD. In contrast, no correlations existed between QST and PPT variables and psychological variables in controls. These results indicate the need to consider that a blend of factors influences the pain thresholds in chronic WAD and emphasize the need for a biopsychosocial model when interpreting QST and PPT variables.
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Anesthesia and analgesia · Mar 2012
Comparative StudyDorsal root ganglion application of muscimol prevents hyperalgesia and stimulates myelin protein expression after sciatic nerve injury in rats.
Peripheral nerve injuries may result in debilitating pain that is poorly responsive to conventional treatment. Neuropathic pain induced by peripheral nerve injury is caused, in part, by ectopic discharges from the injury site or the dorsal root ganglia (DRG) resulting in enhanced central input and central hyperexcitability. A heterogeneous family of γ-aminobutyric acid (GABA)(A) channels is important in quieting neuronal excitability. We have recently reported that in vivo modulation of GABAergic neurons in DRG can alter the course of neuropathic pain development after peripheral nerve injury. It seems that direct application of a potent GABA(A) agonist, muscimol, to the ipsilateral DRG prevents the development of hyperalgesia in rats subjected to a sciatic nerve crush injury. In addition to potentially curtailing hyperexcitability, GABAergic stimulation upregulated expression of peripheral myelin protein 22 (PMP22), a key component of the basal lamina. PMP22 expression correlates with peripheral myelin formation and nerve regeneration. ⋯ The DRG could be a promising therapeutic target in nerve regeneration and pain alleviation after crush injury of a myelinated peripheral nerve.