Pain
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Comparative Study
A comparison of cognitive measures in low back pain: statistical structure and clinical validity at initial assessment.
Four cognitive measures--MHLC, PLC, CSQ and PRSS/PRCS--were directly compared in 120 U. K. patients with chronic low back pain. 80% of the individual items in the PLC and 86% in the CSQ had satisfactory test-retest reliability, as had most of the scales of the CSQ and the PLC PC scale. The items and the scales of the MHLC and the PRSS/PRCS had lower reliability. ⋯ There was also a relationship among cognitive measures and both disability and work loss which persisted even after controlling for severity of pain and depressive symptoms. The present results suggest that the concept of catastrophising has greatest potential for understanding current low back symptoms and that the CSQ may be the most useful measure of this. Other work, however, suggests that the PLC may also be of value in following change and predicting response to treatment.
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Clinical Trial Controlled Clinical Trial
The effects of auricular transcutaneous electrical nerve stimulation (TENS) on experimental pain threshold and autonomic function in healthy subjects.
The present study examines the effects of auricular transcutaneous electrical nerve stimulation (TENS) on electrical pain threshold measured at the ipsilateral wrist and autonomic functions including skin temperature, blood pressure and pulse rate in 24 healthy subjects. TENS was administered as low frequency trains of pulses delivered at a 'strong but comfortable' intensity to 1 of 3 auricular points to be examined: (i) autonomic effects (autonomic point), (ii) pain threshold effects (wrist point), and (iii) placebo effects at an unrelated point (face point). A fourth untreated group was designated as a situation control. ⋯ However, pain threshold was found to increase by over 50% of its pretreatment baseline in 4 subjects and by 30% in 6 subjects. This rise was not dependent upon the site of auricular TENS. The possible mechanisms of such changes are discussed.
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The role of epidural morphine in chronic cancer pain treatment is unresolved. In a population of 1205 cancer patients, the aggressive use of systemic opiates limited the trial of epidural analgesia to 16 cases. ⋯ Complications occurred in 11 of the 16 cases of epidural analgesia and included dislodged or broken catheters, pain on injection, hyperesthesia from epidural morphine and bleeding or infection related to the epidural catheter. Epidural morphine is indicated only in selected cancer pain patients and, although bupivacaine extends the efficacy of epidural analgesia, these methods are accompanied by problems and limitations.
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In patients with unexplained pain after cholecystectomy, morphine often induces pain and may increase plasma aspartate aminotransferase (AST) activity because of exaggerated or prolonged rises in pressure within the biliary system. These anomalous effects of morphine may be mediated by activation of autonomic or related afferent nuclei. In this study, 16 patients with pain and increases in AST after morphine were further studied after pre-treatment with dexamethasone and hydrocortisone. ⋯ Serial changes in plasma concentrations of catecholamines were determined in 8 patients and showed that pre-treatment with dexamethasone, but not hydrocortisone, was associated with lower concentrations of norepinephrine and epinephrine with overall reductions of 53% and 67%, respectively. These observations are consistent with a role for sympatho-adrenomedullary activation in abdominal pain induced by morphine. The different effects of dexamethasone and hydrocortisone raise the possibility that sympatho-adrenomedullary activation after morphine is influenced by the interaction of cortisol with type I glucocorticoid receptors which have a low affinity for dexamethasone and a high affinity for cortisol.
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Comparative Study
Stress-related electromyographic responses in patients with chronic temporomandibular pain.
Surface electromyographic (EMG) recordings from the right and left masseter and the left biceps muscle during stress and non-stress imagery were obtained from patients with temporomandibular myofascial pain and dysfunction syndrome (MPDS), temporomandibular joint disorder (TMJD), chronic low back pain (CBP) and healthy controls (HC). Both the MPDS and the TMJD groups displayed significantly more masseter EMG reactivity to the stressful imagery than the CBP and HC groups. ⋯ The MPDS patients indicated more life stress and gave higher aversiveness ratings during the experiment. These findings are discussed with respect to the validity of the TMJD and MPDS distinction.