The journal of pain : official journal of the American Pain Society
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Randomized Controlled Trial
Effects of anodal transcranial direct current stimulation on chronic neuropathic pain in patients with multiple sclerosis.
Neuropathic pain in patients with MS is frequent and is associated with a great interference with daily life activities. In the present study, we investigated whether anodal transcranial direct current stimulation (tDCS) may be effective in reducing central chronic pain in MS patients. Patients received sham tDCS or real tDCS in a 5-day period of treatment in a randomized, double blind, sham-controlled study. Pain was measured using visual analog scale (VAS) for pain and the short form McGill questionnaire (SF-MPQ). Quality of life was measured using the Multiple Sclerosis Quality of Life-54 scale (MSQoL-54). Depressive symptoms and anxiety were also evaluated as confounding factors using the Beck Depression Inventory (BDI) and VAS for anxiety. Evaluations were performed at baseline, immediately after the end of treatment, and once a week during a 3-week follow-up period. Following anodal but not sham tDCS over the motor cortex, there was a significant pain improvement as assessed by VAS for pain and McGill questionnaire, and of overall quality of life. No depression or anxiety changes were observed. Our results show that anodal tDCS is able to reduce pain-scale scores in MS patients with central chronic pain and that this effect outlasts the period of stimulation, leading to long-lasting clinical effects. ⋯ This article presents a new, noninvasive therapeutic approach to chronic, central neuropathic pain in multiple sclerosis, poorly responsive to current conventional medications. tDCS is known to cause long-lasting changes of neuronal excitability at the site of stimulation and in the connected areas in healthy subjects. This led us to hypothesize that pain decrease may be the result of functional plastic changes in brain structures involved in the pathogenesis of chronic neuropathic pain.
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The Douleur Neuropathique 4 (DN4) questionnaire was developed by the French Neuropathic Pain Group and is a simple and objective tool, with the ability to distinguish nociceptive from neuropathic pain. The purpose of this work was to validate the DN4 questionnaire in the Portuguese language in order to allow its use in clinical and research settings. A double-blind, accuracy study was conducted, consisting of translation, back-translation, literal evaluation, semantic equivalence, and communication with the target population. The Portuguese version of the questionnaire was applied in a sample of 101 patients with neuropathic (N = 42) or nociceptive pain (N = 59), ranked according to medical diagnosis. The reproducibility, reliability and validity of the instrument were analyzed, and showed a high diagnostic power for this version of the DN4 questionnaire. The Portuguese version of the DN4 questionnaire presented good validity and reliability, allowing it to identify neuropathic pain and neuropathic characteristics of mixed pain syndromes. ⋯ This article presents the first validated neuropathic pain questionnaire in the Portuguese language and represents a useful tool in the assessment of neuropathic pain both in the clinical setting and in population-based studies. The sensible and quick format of this instrument are key factors that will contribute to its widespread use, permitting a true recognition of patients with neuropathic pain.
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While sex differences in pain-related coping have been widely reported, little is known on sex differences in changes in coping following multimodal pain treatment and how these changes relate to treatment outcome. The present prospective study therefore aimed to investigate sex differences in coping strategies between boys and girls with chronic pain prior to multimodal inpatient treatment and at 3-month follow-up. Sixty-four boys and 103 girls with various pain disorders were evaluated. Core outcomes (pain intensity and pain-related disability) and coping were assessed via validated questionnaires. At admission, boys and girls used similar coping strategies. Three months following treatment, boys and girls decreased passive pain coping and seeking social support while they maintained the degree of positive self-instruction. Girls displayed higher seeking social support than boys and of importance, only for girls, a reduction in seeking social support was related to decreases in pain intensity. In both groups, the changes in coping were related to positive treatment outcome. Results suggest that both groups may benefit from reductions in passive pain coping and seeking social support. The causal quality of this relationship remains to be determined in future studies. Gender-role expectations and family interactions may account for the sex differences demonstrated for seeking social support. ⋯ Boys and girls with chronic pain show profound similarities in pain-related coping strategies prior and after multimodal pain treatment. The changes in coping are related to positive treatment outcomes. Sex-specific treatment strategies for changing seeking social support may need to be developed and tested for their differential efficacy in boys and girls.
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Catastrophizing is widely recognized as an important risk factor for adverse pain-related outcomes. However, questions remain surrounding the details of its assessment. In particular, recent laboratory studies suggest that evaluation of "situational" catastrophizing (ie, catastrophizing measured during or directly after the administration of noxious stimulation) may provide information distinct from that obtained by standard, or "dispositional" measures, which assess individuals' recall of catastrophizing in daily life. However, comparatively little research has systematically investigated the interrelationships and properties of these 2 different forms of pain-related catastrophizing. The current study evaluated both situational and dispositional catastrophizing measures within multiple samples: healthy individuals (N = 84), patients with painful temporomandibular joint disorders (TMD; N = 48), and patients with painful arthritis (N = 43). All participants first completed the Pain Catastrophizing Scale (PCS), and then underwent psychophysical pain testing, which included heat, cold, and pressure pain. Participants then completed a situational catastrophizing measure with reference to the laboratory pain he/she had just undergone. Situational catastrophizing scores were not significantly correlated with dispositional PCS scores in the healthy participants and arthritis patients, though they were associated in TMD patients. Situational catastrophizing was more strongly associated with experimental pain responses than dispositional PCS scores for the healthy subjects and arthritis patients. In general, higher levels of situational catastrophizing were associated with lower pain thresholds and higher pain ratings across all 3 samples. The findings highlight the importance of multidimensional assessment of pain-related catastrophizing, and suggests a role for measuring catastrophizing related to specific, definable events. ⋯ This study adds to a growing literature examining catastrophizing. Our findings highlight the potential importance of the multidimensional assessment of pain-related catastrophizing, and suggest a role for measuring catastrophizing related to specific, definable events.
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Research generally indicates that providers demonstrate modest insight into their clinical decision processes. In a previous study utilizing virtual human (VH) technology, we found that patient demographic characteristics and facial expressions of pain were statistically significant predictors of many nurses' pain-related decisions. The current study examined the correspondence between the statistically identified and self-reported influences of contextual information on pain-related decisions. Fifty-four nurses viewed vignettes containing a video of a VH patient and text describing a postsurgical context. VH sex, race, age, and facial expression varied across vignettes. Participants made pain-assessment and treatment decisions on visual analogue scales. Participants subsequently indicated the information they relied on when making decisions. None of the participants reported using VH sex, race, or age in their decision process. Statistical modeling indicated that 28 to 54% of participants (depending on the decision) used VH demographic cues. 76% of participants demonstrated concordance between their reported and actual use of the VH facial expression cue. Vital signs, text-based clinical summary, and VH movement were also reported as influential factors. These data suggest that biases may be prominent in practitioner decision-making about pain, but that providers have minimal awareness of and/or a lack of willingness to acknowledge this bias. ⋯ The current study highlights the complexity of provider decision-making about pain management. The VH technology could be used in future research and education applications aimed at improving the care of all persons in pain.