Pain
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The Visual Analogue Scale (VAS), Numerical Rating Scale (NRS), Verbal Rating Scale (VRS), and the Faces Pain Scale-Revised (FPS-R) are among the most commonly used measures of pain intensity in clinical and research settings. Although evidence supports their validity as measures of pain intensity, few studies have compared them with respect to the critical validity criteria of responsivity, and no experiment has directly compared all 4 measures in the same study. The current study compared the relative validity of VAS, NRS, VRS, and FPS-R for detecting differences in painful stimulus intensity and differences between men and women in response to experimentally induced pain. ⋯ The findings are consistent with previous studies supporting the validity of each scale. The most support emerged for the NRS as being both (1) most responsive and (2) able to detect sex differences in pain intensity. The results also provide support for the validity of the scales for use in Portuguese samples.
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Randomized Controlled Trial
Randomized trial of a DVD intervention to improve readiness to self-manage joint pain.
A DVD (digital video disk) intervention to increase readiness to self-manage joint pain secondary to hemophilia was informed by a 2-phase, motivational-volitional model of readiness to self-manage pain, and featured the personal experiences of individuals with hemophilia. The DVD was evaluated in a randomized controlled trial in which 108 men with hemophilia completed measures of readiness to self-manage pain (Pain Stages of Change Questionnaire) before and 6 months after receiving the DVD plus information booklet (n=57) or just the booklet (n=51). The effect of the DVD was assessed by comparing changes in Pain Stages of Change Questionnaire scores (precontemplation, contemplation, and action/maintenance) between groups. ⋯ Significant use×time effects showed that benefits in terms of contemplation and action/maintenance were restricted to those who used the interventions at least once. The results show that low-intensity interventions in DVD format can improve the motivational impact of written information, and could be used to help prepare people with chronic pain for more intensive self-management interventions. The findings are consistent with a 2-phase, motivational-volitional model of pain self-management, and provide the first insights to our knowledge of readiness to self-manage pain in hemophilia.
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The perception of pain is initiated by the transduction of noxious stimuli through specialized ion channels and receptors expressed by primary nociceptive neurons. The molecular mechanisms that orchestrate the expression and function of ion channels relevant for pain processing are poorly understood. We demonstrate here a central role of the transcription factor Smad-interacting protein 1 (Sip1/Zfhx1b/Zeb2), a 2-handed zinc finger DNA-binding protein with essential functions in neural crest and forebrain development, in controlling nociceptive neuron excitability and pain sensitivity. ⋯ Analysis of the voltage-gated currents underlying repetitive firing revealed a significant increase in persistent sodium currents and a reduction in delayed rectifier potassium currents. Modeling experiments in conjunction with experimental results suggest that these changes cause a depolarization-induced block of action potential propagation past the DRG axon T-junction. These data suggest that Sip1 controls the transduction properties of heat-sensitive primary sensory neurons and thus thermal pain sensitivity in a novel manner via coordinated changes in DRG-neuron voltage-gated ion channels.
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This study examined the influence of patients' likability on pain estimations made by observers. Patients' likability was manipulated by means of an evaluative conditioning procedure: pictures of patients were combined with either positive, neutral, or negative personal traits. Next, videos of the patients were presented to 40 observers who rated the pain. ⋯ The effect on pain estimations was only found with regard to patients expressing high-intensity pain. There was no effect on response bias (i.e., the overall tendency to indicate pain). These findings suggest that we take the pain of patients we do not like less seriously than the pain of patients we like.