Pain
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Pain experiences of youth with brain-based developmental disabilities are often overlooked and/or misinterpreted, increasing the risk for poor or inadequate pain assessment and management. Ample measures exist to assess acute and chronic pain, yet their utility and frequency of use in youth with brain-based developmental disabilities is unclear and available measures do not have strong measurement properties for this diverse group. This systematic review identified the scope of self-reported and observer-reported pain assessment in studies of youth (aged 3-24 years) with brain-based developmental disabilities (phase 1) and summarized other measures of pain-related functioning for acute and chronic pain (ie, physical, emotional, social, sleep, and quality of life, within the subset of quantitative studies focused primarily on pain, phase 2). ⋯ Of the 137 articles included in phase 2, other outcomes assessed alongside pain intensity included motor ability (16.8%), adaptive functioning (11%), quality of life (8%), pain interference (6.6%), mental health (5.8%), and communication ability (2.9%). Cerebral palsy was the most common population in both phase 1 (n = 343; 48.5%) and phase 2 (n = 83; 59.7%). This review provides a foundational understanding of pain assessment in brain-based developmental disabilities and highlights continued inequities in holistic pain assessment for this population.
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Decades of efforts in elucidating pain mechanisms, including pharmacological, neuroanatomical, and physiological studies have provided insights into how nociceptive information transmits from the periphery to the brain and the locations receiving nociceptive signals. However, little is known about which specific stimulus-dependent activated neurons, amongst heterogeneous neural environments, discriminatively evoke the cognate pain behavior. We here shed light on the population of neurons in the spinal cord activated by a painful stimulus to identify chronic pain-dependent activated neuronal subsets using Fos2A-iCreER (TRAP2) mice. ⋯ Of interest, spinal neurons expressing calretinin, calbindin, and parvalbumin were activated differently with distinct pain modalities (ie, mechanical allodynia vs heat hyperalgesia). Chemogenetic inhibition of those activated neurons significantly and specifically reduced the response to the pain stimulus associated with the stimulus modality originally given to the animals. These findings support the idea that spinal neuronal ensembles underlying nociceptive transmission undergo dynamic changes to regulate selective pain responses.
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To assess postoperative pain intensity in adults, the numeric rating scale (NRS) is used. This scale has shown acceptable psychometric features, although its scale properties need further examination. We aimed to evaluate scale properties of the NRS using an item response theory (IRT) approach. ⋯ Response categories on the NRS are ordered but have different widths. The interval scale properties of the NRS should be questioned. In dealing with missing linearity in pain intensity ratings using the NRS, IRT methods may be helpful.
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Temporomandibular disorder (TMD) and irritable bowel syndrome (IBS) are 2 chronic overlapping pain conditions (COPCs) that present with significant comorbidity. Both conditions are more prevalent in women and are exacerbated by stress. ⋯ In particular, data indicate that increased activity in the insula and regions of the reward and limbic systems are associated with more pronounced and longer-lasting visceral pain behaviors in female rats, while the faster pain resolution in male rats may be due to increased activity in descending pain inhibitory pathways. These findings suggest the critical role of brain mechanisms in chronic pain conditions and that sex may be a risk factor of developing COPCs.
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Pain sensitivity of healthy subjects in the cold-pressor (CP) test was proposed to be dichotomously distributed and to represent a pain sensitivity trait. Still, it has not been systematically explored which factors influence this pain sensitivity readout. The aim of this study was to distinguish potential contributions of local tissue-related factors such as perfusion and thermoregulation or gain settings in nociceptive systems. ⋯ Baroreceptor activation suppressed pain and cardiovascular responses more efficiently in CP-insensitive subjects. Cold-pressor sensitivity generalized to a pain trait of C-fiber-mediated nociceptive channels, which was independent of local thermal and vascular changes in the ice-water-exposed hand. Thus, the C-fiber pain trait reflects gain setting of the nociceptive system.