Pain
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Randomized Controlled Trial
Comparison of masseter muscle referred sensations after mechanical and glutamate stimulation: a randomized, double-blind, controlled, cross-over study.
Referred sensations (RS) are commonly found in various musculoskeletal pain conditions. Experimental studies have shown that RS can be elicited through glutamate injection and mechanical stimulation. Despite this, differences and similarities between these modalities in RS outcomes remain unclear. ⋯ Hence, RS does not seem to be modality-dependent, and only the painfulness of the stimulus caused an increase in frequency of RS. Finally, RS location for each participant was similar in both sessions possibly indicating a preferred location of referral. These findings may have implications for our understanding of RS in craniofacial pain conditions.
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To address the lack of appropriate patient-defined quality indicators (QIs) for assessment of pain clinic care in the Netherlands, we developed the "Quality Indicators Pain Patients' Perspective" (QiPPP) questionnaire. Quality indicators are widely used to measure the quality of the structure, process, and outcome of health care. The Pain Patient United Consortium, together with the University Pain Centre of Maastricht, developed QIs for assessment of care. ⋯ The mean score for patient comprehensibility was 8.6 ± 1.4. The final QiPPP questionnaire included 21 QIs (18 process; 3 outcome) distributed over 7 domains. The QiPPP questionnaire was of sufficient psychometric quality and found to be useful and understandable by patients with chronic pain.
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It is well-recognized that, despite similar pain characteristics, some people with chronic pain recover, whereas others do not. In this review, we discuss possible contributions and interactions of biological, social, and psychological perturbations that underlie the evolution of treatment-resistant chronic pain. Behavior and brain are intimately implicated in the production and maintenance of perception. ⋯ We propose the concept of "stickiness" as a soubriquet for capturing the multiple influences on the persistence of pain and pain behavior, and their stubborn resistance to therapeutic intervention. We then focus on the neurobiology of reward and aversion to address how alterations in synaptic complexity, neural networks, and systems (eg, opioidergic and dopaminergic) may contribute to pain stickiness. Finally, we propose an integration of the neurobiological with what is known about environmental and social demands on pain behavior and explore treatment approaches based on the nature of the individual's vulnerability to or protection from allostatic load.
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Studies in interictal migraine show either normal or impaired pain modulation, at the psychophysical level. To date, pain modulation in migraineurs has yet to be explored concurrent with imaging methods. We aimed to investigate brain activity associated with endogenous analgesia by functional magnetic resonance imaging in attack-free migraineurs. ⋯ Within groups, controls showed a significant CPM effect (Ts_alone: 6.15 ± 2.03 vs Ts_conditioned: 5.63 ± 1.97; P < 0.001), whereas migraineurs did not (Ts_alone: 5.60 ± 1.92 vs Ts_conditioned: 5.39 ± 2.30; P = 0.153); yet, both groups showed significant CPM-related decreased deactivation in prefrontal areas including the superior frontal gyrus and parietal regions including precuneus. The change in brain activity seems related to task demands rather than to pain reduction. The lack of group difference between migraineurs and controls in CPM and its related brain activity may result from (1) the specific CPM methodology used in this study, since migraineurs are reported to show various pain modulation efficiency for different test paradigms and/or (2) pathophysiological diversity of patients with migraine.