Pain
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Chronic pain is currently considered a public health problem with high costs to the individual and society. To improve prevention and treatment of chronic pain, epidemiologic studies are mandatory for assessing chronic pain. The aims of this study were to estimate the prevalence of chronic pain in the adult Danish population and to analyze associated factors such as diseases, immigration, and opioid use. ⋯ The study population consisted of 14,925 individuals in whom a high prevalence of chronic pain (26.8%, 95% confidence interval: 26.1 to 27.5) and a high prevalence of opioid consumption (4.5%) were observed. Other aspects of particular note: (1) a higher prevalence of chronic pain occurred among individuals with cardiovascular and chronic pulmonary diseases than among individuals with cancer; and (2) individuals with a non-Western background reported a higher pain prevalence, higher pain intensities, and more widespread pain than individuals with Danish background; however, opioids were more frequently used by native Danes. The prevalence of chronic pain as well as opioid use in Denmark are alarmingly high, and the relevance of opioid consumption is unknown.
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The aim of this study was to establish the somatosensory profiles of patients with cervical radiculopathy and patients with nonspecific neck-arm pain associated with heightened nerve mechanosensitivity (NSNAP). Sensory profiles were compared to healthy control (HC) subjects and a positive control group comprising patients with fibromyalgia (FM). Quantitative sensory testing (QST) of thermal and mechanical detection and pain thresholds, pain sensitivity and responsiveness to repetitive noxious mechanical stimulation was performed in the maximal pain area, the corresponding dermatome and foot of 23 patients with painful C6 or C7 cervical radiculopathy, 8 patients with NSNAP in a C6/7 dermatomal pain distribution, 31 HC and 22 patients with FM. ⋯ Both neck-arm pain groups demonstrated increased cold sensitivity in their maximal pain area (P<.03) and the foot (P<.009), and this was also the dominant sensory characteristic in patients with NSNAP. Both neck-arm pain groups differed from patients with FM, the latter characterised by a widespread gain of function in most nociceptive parameters (thermal, pressure, mechanical pain sensitivity P<.027). Despite commonalities in pain characteristics between the 2 neck-arm pain groups, distinct sensory profiles were demonstrated for each group.
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Motor cortex stimulation is generally suggested as a therapy for patients with chronic and refractory neuropathic pain. However, the mechanisms underlying its analgesic effects are still unknown. In a previous study, we demonstrated that cortical stimulation increases the nociceptive threshold of naive conscious rats with opioid participation. ⋯ Furthermore, motor cortex stimulation enhanced neuronal firing rate and Fos immunoreactivity in the ipsilateral periaqueductal gray. We have also observed a decreased Zif268, δ-aminobutyric acid (GABA), and glutamic acid decarboxylase expression within the same region, suggesting an inhibition of GABAergic interneurons of the midbrain periaqueductal gray, consequently activating neurons responsible for the descending pain inhibitory control system. Taken together, the present findings suggest that inhibition of thalamic sensory neurons and disinhibition of the neurons in periaqueductal gray are at least in part responsible for the motor cortex stimulation-induced antinociception.
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The communication of pain has received a great deal of attention in the pain literature; however, one form of pain communication--emotional disclosure of pain-related distress (e.g., sadness, worry, anger about pain)--has not been studied extensively. This study examined the extent to which this form of pain communication occurred during an observed conversation with one's spouse and also investigated the correlates and consequences of disclosure. Individuals with chronic pain (ICP) and their spouses (N=95 couples) completed several questionnaires regarding pain, psychological distress, and relationship distress as well as video recorded interactions about the impact of pain on their lives. ⋯ Furthermore, spouses were more likely to engage in invalidation after attempting more neutral or validating responses, suggesting an erosion of support when ICPs engaged in high rates of disclosure. Correlates of spousal invalidation included both spouses' helplessness catastrophizing, ICPs' affective distress about pain, and spouses' anxiety, suggesting that both partners' distress are implicated in maladaptive disclosure-response patterns. Findings are discussed in light of pain communication and empathy models of pain.