Pain
-
The current study examined the prospective relationship between pain-related fear and altered motor behavior, as well as perceived interference, among 51 healthy participants following induction of delayed-onset muscle soreness (DOMS) to the trunk extensor muscles. Healthy participants without history of back pain completed standardized reaches to high and low targets at self-paced and rapid speeds before and after induction of acute low back pain using a DOMS paradigm. Pain-related fear was assessed prior to DOMS induction. ⋯ Pain-related fear scores were not predictive of lumbar flexion during baseline, but predicted reduced lumbar flexion during self- and fast-paced trials to low target locations once DOMS was induced. Pain-related fear was likewise predictive of perceived interference in life activities following DOMS induction. The findings suggest that initially pain-free individuals with high pain-related fear adopt avoidant spinal strategies during common reaching movements shortly after injury is sustained, which may comprise a risk factor for future pain and disability.
-
Knowledge regarding mortality as a potential consequence of being sickness absent because of musculoskeletal diagnoses is almost nonexistent. The association between sickness absence because of musculoskeletal diagnoses and risk of premature death was examined in a prospective, nationwide, population-based cohort study based on Swedish registers. Included were all 4,760,987 individuals who were living in Sweden December 31, 2005, aged 20 to 64 years, and not on disability or old-age pension. ⋯ Similar associations were observed among both women and men. Moreover, increased mortality risks due to tumors (HR=1.6-1.7), circulatory diseases (HR=1.2-1.5), mental disorders (HR=1.2-3.2), and suicide (HR=1.5-1.9) were observed among persons sickness absent because of musculoskeletal diagnoses. This nationwide cohort study reveals, for the first time, an increased risk of premature death among both women and men sickness absent because of musculoskeletal diagnoses after adjustment for several potential confounders.
-
An abundance of animal research suggests that fear inhibits pain whereas anxiety increases it. Human studies on this topic are more scarce, and the existing evidence seems rather inconsistent. Therefore, we aimed to investigate the divergent effects of both negative emotional states-that is, pain-related fear and anxiety on pain sensitivity and unpleasantness. ⋯ Moreover, this sex-specific sensitization is partially mediated by (conditioned) fear of movement-related pain. Women also report increasingly more fear of pain over conditioning blocks, while men do not. These results might be interesting in the light of the overrepresentation of women in a number of clinical pain conditions as well as anxiety disorders.
-
Touch gating, the attenuation of tactile sensitivity in the presence of pain, is a well-documented phenomenon, but its mechanism is unknown. The ability of pain to capture attention suggests that touch gating may be an example of distraction, but the fact that pain raises tactile but not auditory thresholds argues that touch gating is a form of somatosensory interaction. Therefore, the present study was carried out to determine whether touch gating is the result of sensory or cognitive interference. ⋯ For comparison, a form of unambiguously cognitive interference, the Stroop effect, was also measured repeatedly; it declined significantly across sessions, unlike touch gating interference. Finally, touch gating was not correlated with measures of participants' distractibility, fear of pain, hypervigilance, or anxiety, variables previously found to influence pain on a cognitive level. Taken together, the results suggest that touch gating is a robust, stimulus-locked form of sensory interaction, rather than a transitory result of distraction or other cognitive processes.
-
Spinal glial and proinflammatory cytokine actions are strongly implicated in pathological pain. Spinal administration of the anti-inflammatory cytokine interleukin (IL)-10 abolishes pathological pain and suppresses proinflammatory IL-1β and tumor necrosis factor alpha (TNF-α). Drugs that bind the cannabinoid type-2 receptor (CB(2)R) expressed on spinal glia reduce mechanical hypersensitivity. ⋯ In spinal gp120 animals, AM1710 prevented bilateral mechanical hypersensitivity. For comparison to immunohistochemistry, IL-1β and TNF-α protein quantification from lumbar spinal and DRG homogenates was determined, and revealed increased DRG IL-1β protein levels from gp120, that was robustly prevented by AM1710 pretreatment. Cannabilactone CB(2)R agonists are emerging as anti-inflammatory agents with pain therapeutic implications.