European journal of pain : EJP
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The aim of the present study was to compare the subjectively reported and objectively assessed activity-related characteristics of patients with Chronic Low Back Pain (CLBP) who were classified according to their scores on the Patterns of Activity Measure-Pain (POAM-P) into avoiders, persisters, mixed performers (i.e. high scores on both avoidance and persistence behaviour) or functional performers (i.e. low scores on avoidance and persistence behaviour). Patients carried an electronic diary during 14 days to assess the self-reported activity and pain intensity levels in daily life. An accelerometer was used to objectively assess their activity level during the same time period. ⋯ A further analysis tested the association between pain intensity levels and self-reported and objectively assessed daily life activity levels in avoiders and persisters. In persisters, a higher level of self-reported activities in daily life was related to increased pain. The objectively assessed activity level was not associated with pain intensity.
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Major efforts to develop objective measurement tools for neonatal pain assessment have been made. However, the challenge of measuring pain in neonates remains suggesting that contextual factors (cFs) might alter their responses to pain. Although the role of cFs is increasingly discussed as crucial for pain assessment, they are not well described in the literature and are rarely considered in the clinical setting despite their importance. ⋯ This review supports the influence of some cFs on pain response. However, the results remain inconclusive which may be, in part, related to the heterogeneity of the studies. Contextual factors need further investigation for a better understanding of the magnitude of their effect on pain response.
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This study examined differences between Asians and non-Hispanic Whites (Whites) in pain sensitivity, and its relationship to mean arterial pressure (MAP) and heart rate (HR). In 30 Whites (50% female) and 30 Asians (50% female), experimental pain sensitivity was assessed with a hand cold pressor task, yielding measures of pain threshold, tolerance, intensity, and unpleasantness. Mean arterial pressure and HR measurements taken at rest and in response to speech stress were assessed. ⋯ These results indicate that Asian Americans are more sensitive to experimental pain than Whites and suggest ethnic differences in endogenous pain regulatory mechanisms (e.g. MAP and HR). The results may also have implications for understanding ethnic differences in clinical pain.
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Reactive oxygen species (ROS) are known to be involved in the pathophysiology of complex regional pain syndrome type I (CRPS I). Since the mitochondrial respiratory chain is a major source of ROS, we hypothesized that mitochondria play a role in the pathophysiology of CRPS I. The hypothesis was tested by studying mitochondrial energy metabolism in muscle tissue from amputated limbs of CRPS I patients. ⋯ Moreover, we observed reactive oxygen species evoked damage to mitochondrial proteins and reduced MnSOD levels. It remains to be established if the mitochondrial dysfunction that is apparent at the end-stage of CRPS I is also present in earlier stages of the disease, or are secondary to CRPS I. The observation of a reduced mitochondrial energy production combined with reactive oxygen species induced damage in muscle tissue from CRPS I patients warrants further studies into the involvement of mitochondrial dysfunctioning in the pathophysiology of CRPS I.
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While the etiology of fibromyalgia syndrome (FMS) remains unclear, it is assumed that both peripheral and central components are involved. ⋯ Repetitive proton/PGE(2)-induced excitation of muscle tissue led to a more prolonged perception of pain and more wide-spread activation in pain-related brain areas in FMS, especially in the left (ipsilateral) insula, whereas acute protons/PGE(2)-induced pain processing was similar in the two groups. These data provide further evidence for enhanced central pain processing in FMS patients.