Pain
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Randomized Controlled Trial Comparative Study
Spinal cord stimulation normalizes abnormal cortical pain processing in patients with cardiac syndrome X.
Cardiac syndrome X (CSX) is characterized by effort angina, ST-segment depression during stress tests and normal coronary arteries. Abnormal nociception was suggested in these patients by studies showing a reduced cardiac pain threshold; furthermore, we recently found a lack of habituation to pain stimuli using recording of laser evoked potentials (LEPs). In CSX patients with severe angina, spinal cord stimulation (SCS) was shown to improve symptoms. ⋯ Similar results were observed during right-hand stimulation. Our study shows that in CSX patients SCS is able to restore habituation to peripheral pain stimuli. This effect might contribute to restore the ability of CSX patients to better tolerate cardiac pain.
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Comparative Study
Psychological predictors of pain expression and activity intolerance in chronic pain patients.
Recent research suggests that communicative and protective pain behaviors represent functionally distinct subsystems of behavior associated with pain. The present research examined whether components of pain experience such as pain severity, catastrophizing and fear of pain were differentially associated with communicative and protective pain behaviors. It was predicted that pain severity would be associated with decreased physical tolerance and heightened expression of pain behavior. ⋯ This study provides additional evidence for the functional distinctiveness of different types of pain expression and provides preliminary evidence for the functional distinctiveness of pain expression and activity intolerance. Discussion addresses the processes by which psychological factors might influence the display of different types of pain behaviors. Discussion also addresses how different types of interventions might be required to specifically target the sensory and behavioral dimensions of the pain system.
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Comparative Study
Characteristics of chronic ischemic pain in patients with peripheral arterial disease.
Chronic ischemic pain is a leading cause of pain in the lower extremities. A neuropathic component in ischemic pain has been shown. Neuropathic pain questionnaires are established as a common tool in pain research. ⋯ The results suggest that the character of ischemic pain changes from nociceptive pain in patients with CI to predominantly neuropathic pain in patients with CLI. A neuropathic pain component seems to be a serious aspect in CLI, while it is not in CI. Questionnaires might be a helpful tool to investigate and diagnose ischemic pain.
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Comparative Study
Assessing fear in patients with cervical pain: development and validation of the Pictorial Fear of Activity Scale-Cervical (PFActS-C).
The fear avoidance model (FAM) postulates that fear of pain or reinjury is a risk factor for persistent pain and disability, because it leads to the avoidance of physical activity. Research on the FAM has not yielded consistent results, which may be attributed to the model itself, but could also be a product of the way fear of movement is assessed. Studies of the FAM have measured fear using verbal scales consisting of items that are often vague and have only an indirect relationship with fear. ⋯ Internal consistency (alpha=.98), stability over time (n=44, IntraClass Correlation=.72), and construct validity were all good to excellent. The results indicate that the PFActS-C may be a useful tool for assessing fear of movement in patients with cervical pain. Research is needed to confirm the factor structure of the PFActS-C and to assess the generalizability of the results to other samples with neck pain.
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Comparative Study
Cholinergic mechanisms involved in the pain relieving effect of spinal cord stimulation in a model of neuropathy.
The mechanisms underlying the pain relieving effect of spinal cord stimulation (SCS) on neuropathic pain remain unclear. We have previously demonstrated that suppression of tactile hypersensitivity produced by SCS may be potentiated by i.t. clonidine in a rat model of mononeuropathy. Since the analgesic effect of this drug is mediated mainly via cholinergic mechanisms, a study exploring the possible involvement of the spinal cholinergic system in SCS was undertaken. ⋯ In another group of rats it was found that the response to SCS was completely eliminated by i.t. atropine and a muscarinic M(4) receptor antagonist while a partial attenuation was produced by M(1) and M(2) antagonists. Blocking of nicotinic receptors did not influence the SCS effect. In conclusion, the attenuating effect of SCS on pain related behavior is associated with the activation of the cholinergic system in the dorsal horn and mediated via muscarinic receptors, particularly M(4,) while nicotinic receptors appear not to be involved.