Pain
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Case Reports
Why is depression comorbid with chronic myofascial face pain? A family study test of alternative hypotheses.
A number of explanations have been proposed to account for findings that rates of depression are elevated in persons with chronic, non-malignant pain disorders (CNPDs); for example, that CNPDs are variants of depression (e.g. 'masked depression'), that the stress of living with CNPDs contribute to the onset of depression ('diathesis-stress'), or that the correlation of CNPDs and depression is a methodological artifact of studying treatment-seeking samples. These alternative hypotheses are tested for one specific CNPD, chronic myofascial face pain, using a family study methodology. The procedure was to conduct direct psychiatric interviews with 106 patients with a history of carefully diagnosed myofascial face pain, 118 acquaintance controls without personal histories of myofascial face pain, and a random sample of adult first degree relatives of these case and control probands. ⋯ This outcome is consistent with the hypothesis that living with chronic myofascial face pain contributes to elevated rates of depression. It is inconsistent with the alternative hypotheses that this CNPD is a variant of depression or that the elevated MDD rates are simply an artifact of selection into treatment. The implications of these results and additional results consistent with them are discussed.
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Following pediatric eye surgery, visual scales for assessment of recovery are inadequate due to impairment of vision. A tactile scale (TaS) was therefore developed and tested in a pilot-trial. Fifty children, 23 girls and 27 boys undergoing different types of ophthalmic surgery used TaS to rate postoperative pain and nausea. ⋯ The mean ratings of pain by TaS were significantly (P<0.05, General Linear Model followed by Dunnett's t-test) lower up to 3 h after the administration of analgesics compared to ratings before analgesics were given, indicating that ratings by TaS were related to the children's actual level of pain. Nausea and/or vomiting was common and was reported or recorded in 28 children (56%). After further validation, TaS may be a useful tool for assessment of postoperative pain and efficacy of given treatments in children and adults, not only after eye procedures, but also following other types of surgery.
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Clinical Trial
Electrical stimulation of motor cortex for pain control: a combined PET-scan and electrophysiological study.
Although electrical stimulation of the precentral gyrus (MCS) is emerging as a promising technique for pain control, its mechanisms of action remain obscure, and its application largely empirical. Using positron emission tomography (PET) we studied regional changes in cerebral flood flow (rCBF) in 10 patients undergoing motor cortex stimulation for pain control, seven of whom also underwent somatosensory evoked potentials and nociceptive spinal reflex recordings. The most significant MCS-related increase in rCBF concerned the ventral-lateral thalamus, probably reflecting cortico-thalamic connections from motor areas. ⋯ A model of MCS action is proposed, whereby activation of thalamic nuclei directly connected with motor and premotor cortices would entail a cascade of synaptic events in pain-related structures receiving afferents from these nuclei, including the medial thalamus, anterior cingulate and upper brainstem. MCS could influence the affective-emotional component of chronic pain by way of cingulate/orbitofrontal activation, and lead to descending inhibition of pain impulses by activation of the brainstem, also suggested by attenuation of spinal flexion reflexes. In contrast, the hypothesis of somatosensory cortex activation by MCS could not be confirmed by our results.
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We investigated gender differences in cardiovascular and pain responses to the cold pressor (CP) test in persons with positive (PH+) or negative parental history (PH-) for hypertension. Previous work has suggested an attenuated sensitivity to painful stimulation in hypertensive men and more recently in men with parental disposition for hypertension. It is not known whether this hypoalgesic effect is present in PH+ women. ⋯ Although pain ratings during the CP did not differ between groups, post-CP reported pain receded faster in the PH+ men than in the PH- men. PH+ women, on the other hand, tended to report greater pain than PH- women. These findings question the generalizability of the hypoalgesic effects in hypertension-prone women.
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Randomized Controlled Trial Multicenter Study Comparative Study Clinical Trial
Comparative reliability and validity of chronic pain intensity measures.
Reliable and valid measures of pain are essential for conducting research on chronic pain. The purpose of this longitudinal study was to compare the reliability and validity of several measures of pain intensity. One hundred twenty-three patients with chronic pain were administered telephone interview versions of 0-10 scales of current, worst, least and average pain, immediately prior to beginning a multidisciplinary treatment program. ⋯ Contrary to prediction, the composite measures did not show a statistically significant superiority to the individual ratings in terms of their ability to detect change in pain intensity from pre-treatment to various points after treatment. The composite scores did, however, show greater stability than did the individual ratings after treatment. The practical conclusions of this study are; (1), individual 0-10 pain intensity ratings have sufficient psychometric strengths to be used in chronic pain research, especially research that involves group comparison designs with relatively large sample sizes, but, (2), composites of 0-10 ratings may be more useful when maximal reliability is necessary, (e.g. in studies with relatively small sample sizes, or in clinical settings where monitoring of changes in pain intensity in individuals is needed).