Pain
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Clinical Trial
Validity of an illness severity measure for headache in a population sample of migraine sufferers.
The headache impact questionnaire (HImQ) is used to measure pain and activity limitations from headache over a 3-month recall period. In a prior study, the test-retest reliability of the eight-item HImQ score was found to be relatively high (0.86). In the current study, we examined the validity of the eight-item HImQ by comparing the overall score and individual items to equivalent measures from a 90-day diary. ⋯ The validity of illness severity measures may be improved by using frequency-based questions to assess both missed activity days and days with significantly reduced effectiveness or productivity (e.g. by 50% or more). By combining the count for both missed days and days where productivity is substantially reduced, the mean of the frequency-based measure will be increased, a factor which may improve the overall validity of the item. A severity measure can be derived from such items by simple addition and provides a scale with intuitively meaningful units.
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Randomized Controlled Trial Clinical Trial
The effects of disclosure on pain during dental hygiene treatment: the moderating role of catastrophizing.
Catastrophizers and non-catastrophizers were asked to disclose about their dental worries prior to undergoing dental hygiene treatment. It was hypothesized that the effects of emotional disclosure would vary as a function of the level of catastrophizing; where catastrophizers would be more likely than non-catastrophizers to show reductions in pain and emotional distress. The study also examined whether emotional disclosure influenced subsequent levels of catastrophizing and dental anxiety. ⋯ The interaction between condition and level of catastrophizing remained significant even when controlling for emotional distress and the emotional content of the thought records. While catastrophizers benefited from disclosure in regard to their immediate physical and emotional experience, their levels of catastrophizing and dental anxiety remained essentially unchanged. Theoretical and clinical implications of the findings are discussed.
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Anatomical and physiological studies in animals, as well as functional imaging studies in humans have shown that multiple cortical areas are activated by painful stimuli. The view that pain is perceived only as a result of thalamic processing has, therefore, been abandoned, and has been replaced by the question of what functions can be assigned to individual cortical areas. The following cortical areas have been shown to be involved in the processing of painful stimuli: primary somatosensory cortex, secondary somatosensory cortex and its vicinity in the parietal operculum, insula, anterior cingulate cortex and prefrontal cortex. ⋯ The affective-motivational component is close to what may be considered 'suffering from pain'; it is clearly related to aspects of emotion, arousal and the programming of behaviour. This dichotomy, however, has turned out to be too simple to explain the functional significance of nociceptive cortical networks. Recent progress in imaging technology has, therefore, provided a new impetus to study the multiple dimensions of pain.
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Case Reports
A case of reflex sympathetic dystrophy (complex regional pain syndrome, type I) resolved by cerebral contusion.
We present a case of refractory reflex sympathetic dystrophy (RSD) (complex regional pain syndrome, type I) whose symptoms (ongoing pain, allodynia, hyperhydrosis and temperature abnormalities) were resolved after the patient suffered a traumatic cerebral contusion in the left temporal lobe, which caused no neurological deficit. This case suggests that symptoms of some RSD patients may largely sustained by a complex network involving the brain.
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Recently, Cervero and Laird (NeuroReport, 7 (1996) 526-528; Pain, 68 (1996) 13-23) proposed a new pathophysiological mechanism of dynamic mechanical allodynia in skin. Using the capsaicin pain model in humans, they showed that light mechanical stimulation within an area of secondary mechanical allodynia induces vasodilatation measured by laser-Doppler flowmetry. They suggested that the low-threshold A beta-mechanoreceptive fibres depolarize the central terminals of nociceptive primary afferent neurons via interneurons. ⋯ In conclusion, electrical stimulation of A beta-fibres in allodynic skin does not induce antidromic vasodilatation. Consequently, interaction of A beta-mechanoreceptive fibres and nociceptive C-fibres at a presynaptic level is unlikely to produce antidromically conducted impulses and therefore cannot explain the pathophysiology of mechanical allodynia. Alternatively, it is much more likely that under pathophysiological conditions, activity in A beta-fibres may activate nociceptive second-order neurons, i.e. in the spinal cord.