Pain
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Little is known about the extent to which individuals vary versus remain stable in their pain-related catastrophizing, or to which catastrophizing is associated with pain and related problems on a daily basis. We used daily electronic interviews to examine the: (1) reliability and validity of a brief daily catastrophizing measure; (2) stability of catastrophizing; (3) patient characteristics associated with catastrophizing; (4) associations between catastrophizing and concurrent and subsequent outcomes (pain, activity interference, jaw use limitations, and negative mood), between and within patients; and (5) associations between pain and subsequent catastrophizing. One hundred patients with chronic temporomandibular disorder pain completed electronic interviews three times a day for 2 weeks [mean (SD) number of interviews=46 (15)]. ⋯ Daily catastrophizing was associated significantly with concurrent outcomes, between- and within-subjects (P < 0.001); however, associations with same-day subsequent outcomes were greatly attenuated after adjusting for prior outcome levels. Similarly, daily pain was associated significantly with subsequent catastrophizing, but this association was no longer statistically significant after adjusting for prior catastrophizing. The data indicate that catastrophizing is stable over short periods of time in the absence of substantial change in pain, and that within patients, times of greater catastrophizing are associated with worse pain, disability, and mood.
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Comparative Study
Neuroelectric source imaging of steady-state movement-related cortical potentials in human upper extremity amputees with and without phantom limb pain.
Whereas several studies reported a close relationship between changes in the somatotopic organization of primary somatosensory cortex and phantom limb pain, the relationship between alterations in the motor cortex and amputation-related phenomena has not yet been explored in detail. This study used steady-state movement-related cortical potentials (MRCPs) combined with neuroelectric source imaging to assess the relationship of changes in motor cortex and amputation-related phenomena such as painful and non-painful phantom and residual limb sensations, telescoping, and prosthesis use. Eight upper limb amputees were investigated. ⋯ Non-painful phantom sensations as well as painful and non-painful residual limb sensations were unrelated to motor cortical reorganization. A higher amount of motor reorganization was associated with less daily prosthesis use, which also tended to be related to more severe phantom limb pain. These results extend previous findings of a positive relationship between somatosensory reorganization and phantom limb pain to the motor domain and suggest a potential positive effect of prosthesis use on phantom limb pain and cortical reorganization.
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Comparative Study
Differentiating sensory and affective-sensory pain descriptions in patients undergoing magnetic resonance imaging for persistent low back pain.
The study design is a cross-sectional survey with psychometric analysis. The objective is to determine the validity of a modified version of the Short-Form McGill Pain Questionnaire (SF-MPQ). The SF-MPQ has been widely used to differentiate between reports of sensory and affective pain. ⋯ Correlations with measures of pain intensity and the RM were significant, but slightly lower, for the subscales of the modified 2-factor solution (0.26-0.40) than for the subscales of the previously described 2-factor solutions (0.34-0.45). The MSF-MPQ can be used as a brief tool to differentiate the language used to describe pain in patients who are undergoing lumbar MRI. The evidence indicates that this clinical tool can be used to categorize how these patients describe their pain and potentially may be very valuable in determining the optimal course of treatment.
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Comparative Study
P300-amplitudes in upper limb amputees with and without phantom limb pain in a visual oddball paradigm.
The aim of the study was to investigate to what extent cortical hyper-reactivity to visual stimuli is present in upper limb amputees. Five amputees with phantom limb pain (PLP), five amputees without PLP (Non-PLP) and 10 healthy controls (HC) were investigated using a visual oddball paradigm. Two hundred visual stimuli were presented with target stimuli occurring at a probability of 25% and standard stimuli at a probability of 75%. ⋯ The size of the P300-amplitude was positively correlated with the intensity of PLP. These findings suggest a higher magnitude of non-specific cortical excitability in amputees with PLP and a reduced excitability in amputees without PLP. This extends previous findings of differences in cortical excitability in PLP and non-PLP patients in the sensorimotor domain.
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Comparative Study
Sensitization to bradykinin B1 and B2 receptor activation in UV-B irradiated human skin.
Bradykinin B1 and B2 receptors contribute to nociceptor sensitization under inflammatory conditions. Here, we examined the vascular inflammatory responses and nociceptive effects resulting from activation of B1 and B2 receptors in healthy and UV-B irradiated skin in human volunteers. The B1 receptor agonist des-Arg(10)-Kallidin (10(-6)-10(-3)M) and the B2 receptor agonist bradykinin (10(-9)-10(-4)M) were administered by dermal microdialysis to the ventral thigh. ⋯ In normal skin, both B1 and B2 receptor activation dose-dependently evoked pain, vasodilatation and protein extravasation. In UV-B irradiated skin, pain sensation and axon reflex vasodilatation were enhanced by both B1 and B2 agonists, whereas local vasodilatation was increased only following B1 receptor activation. The UV-B irradiation did not enhance B1 and B2 receptor-induced protein extravasation indicating a differential sensitization of the neuronal, but not the vascular response.