Pain
-
Minimally important difference (MID) refers to the smallest meaningful difference that carries implications for patient care. Minimally important differences are necessary to help interpret patient-reported pain outcomes in research and clinical practice. The PROMIS pain interference scales were validated across diverse samples; however, more information about their MIDs could improve their interpretability. ⋯ For the nonpain sample, MID estimates ranged from 3.5 to 4.5 T-score points. The MID estimates were comparable across the 4 fixed-length scales. These MIDs can be used to evaluate treatment effects in research and clinical care and to calculate estimates for powering clinical trials.
-
Multicenter Study Observational Study
Validation of the "Pain Block" concrete ordinal scale for children aged 4 to 7 years.
Pain scales using faces are commonly used tools for assessing pain in children capable of communicating. However, some children require other types of pain scales because they have difficulties in understanding faces pain scales. The goal of this study was to develop and validate the "Pain Block" concrete ordinal scale for 4- to 7-year-old children. ⋯ The differences in mean scores between the painful group and nonpainful group were 3.3 (95% confidence interval, 2.6-4.1) and 3.8 (95% confidence interval, 3.1-4.6) for FPR-S and Pain Block, respectively. The pain scores for both pain scales were significantly decreased when analgesics or pain-relieving procedures were administered (difference in Pain Block, 2.4 [1.4-3.3]; and difference in FPS-R, 2.3 [1.3-3.3]). The Pain Block pain scale could be used to assess pain in 4- to 7-year-old children capable of understanding and counting up to the number 5, even if they do not understand the FPS-R pain scale.
-
Nociception reliably elicits an autonomic nervous system (ANS) response. Because pain and ANS circuitry interact on multiple spinal, subcortical, and cortical levels, it remains unclear whether autonomic responses are simply a reflexive product of noxious stimulation regardless of how stimulation is consciously perceived or whether the experience of pain mediates ANS responses to noxious stimulation. To test these alternative predictions, we examined the relative contribution of noxious stimulation and individual pain experience to ANS responses in healthy volunteers who underwent 1 or 2 pain assessment tasks. ⋯ Although both pain and noxious heat stimulation predicted skin conductance response and pupil dilation response in separate analyses, the individual pain experience statistically mediated effects of noxious heat on both outcomes. Furthermore, moderated mediation revealed that evidence for this process was stronger when stimulation was perceived as painful compared with when stimulation was perceived as nonpainful. These findings suggest that pain appraisal regulates the heat-evoked autonomic response to noxious stimulation, documenting the flexibility of the autonomic pain response to adjust to perceived or actual changes in environmental affordances above and beyond nociceptive input.
-
This study explored whether group size and group member characteristics (age, sex, and compensation status) were associated with patient outcomes (changes in pain and disability). Retrospective analyses of outcome data obtained from 2 independently run group cognitive behavioural therapy (CBT) programs for chronic pain (Program A: N = 317 and Program B: N = 693) were conducted. ⋯ The results of our analyses confirm the contribution of group composition to individual treatment outcomes in group CBT for chronic pain, and highlight factors that have the potential to contribute to group-level variability in patient outcomes. Further research is needed to identify the mechanisms that account for the impact of group characteristics on the efficacy of CBT for chronic pain.
-
The mechanisms whereby deposition of monosodium urate (MSU) crystals in gout activates nociceptors to induce joint pain are incompletely understood. We tried to reproduce the signs of painful gouty arthritis, injecting into the knee joint of rats suspensions containing amorphous or triclinic, needle MSU crystals. The magnitude of MSU-induced inflammation and pain behavior signs were correlated with the changes in firing frequency of spontaneous and movement-evoked nerve impulse activity recorded in single knee joint nociceptor saphenous nerve fibers. ⋯ Intra-articular injection of hyaluronan (HA, Synvisc), a high-MW glycosaminoglycan present in the synovial fluid with analgesic effects in osteoarthritis, significantly reduced MSU-induced behavioral signs of pain and decreased the enhanced joint nociceptor activity. Our results support the interpretation that pain and nociceptor activation are not triggered by direct mechanical stimulation of nociceptors by MSU crystals, but are primarily caused by the release of excitatory mediators by inflammatory cells activated by MSU crystals. Intra-articular HA decreased behavioral and electrophysiological signs of pain, possibly through its viscoelastic filtering effect on the mechanical forces acting over sensitized joint sensory endings and probably also by a direct interaction of HA molecules with the transducing channels expressed in joint nociceptor terminals.