Browse by Audience
Abnormal endogenous pain modulation (EPM) was suggested as a pathophysiological characteristic of chronic pain. EPM has been investigated using psychophysical tests for pain facilitation and inhibition such as temporal summation of pain and conditioned pain modulation, respectively. Another psychophysical test for pain inhibition is offset analgesia (OA), where small variations in noxious stimulus intensity over time elicit a disproportionately large analgesic response. OA has been investigated in patients with mixed pain conditions, but not in chronic temporomandibular disorders (TMD) patients.
Learn More >Cannabis is commonly used to manage chronic pain, but cannabis use patterns among individuals with chronic pain has not been well-characterized. We report cannabinoid, administration route, and product selection preferences among medical cannabis users with chronic pain from an ongoing, online survey. We also examined whether these preferences are affected by differences in sex, intentions behind use (medical only [MED] vs. medical + recreational [MEDREC]), and experience with cannabis (novice: <1 year vs. experienced: ≥1 year). 1,321 participants (59% female) completed the survey. 76.5% of participants used cannabis every day. 93.4% used 2 or more administration routes, with 72.5% using 3 or more. Female, MED, and novice users were less likely to smoke or vaporize (all p < 0.0001), but more likely to rank edibles, tinctures, and topicals as a first-choice administration route than their counterparts. Female and MED users also preferred low THC: high CBD ratios significantly more than their counterparts. Overall, only 2.6% of participants selected cannabis products with input from a medical professional, although 54.9% relied on advice from dispensary employees. More male, MEDREC, and experienced users selected products based on factors that reflected greater comfort with cannabis (e.g., smell, visual properties, cannabis variety). The wide variability in cannabis use among these different groups indicates the need for further research to investigate how specific use routines relate to clinical outcomes. Perspective: Medical cannabis users with chronic pain show distinct differences in cannabinoid preferences and administration associated with user sex, intentions behind use, and experience with cannabis. This article highlights the wide variability in cannabis preferences among medical cannabis users with chronic pain, which may be relevant for clinical outcomes.
Learn More >Poor sleep quality has been associated with greater pain and fatigue in people living with osteoarthritis (OA). The objective of this micro-longitudinal study was to determine whether sleep impacts the diurnal pattern of next-day OA-related pain and fatigue. Community-dwelling older adults (≥65 years) with hip and/or knee OA provided data over 5 days using daily diaries and wrist-worn actigraphs. Pain and fatigue intensity were measured on awakening, at 11 am, 3 pm, 7 pm, and bedtime. Subjective previous night sleep quality was measured on awakening. Multilevel linear regression models examined interactions between sleep variables and time of next-day symptom reports. One hundred sixty participants provided 785 days of data (median age = 71 years; 62% female). Analysis of time interaction effects identified an association between poor sleep quality and more morning pain and fatigue. Although the effect on awakening was more pronounced for fatigue, differences in both symptoms attributable to sleep quality attenuated as the day progressed. Investigation of actigraphy-based sleep parameters revealed no significant interactions with time of symptom measurement. These findings observed in a sample of older adults with mild-to-moderate OA symptoms warrant further investigation in a sample with more severe symptoms and more pronounced sleep dysfunction and/or sleep disorders. PERSPECTIVE: This article investigates the impact of sleep on next-day pain and fatigue of older adults with OA. On awakening from a night of poor quality sleep, pain and fatigue intensity were heightened. However, the effect was not sustained throughout the day, suggesting the morning may be an optimal time for symptom interventions.
Learn More >Attachment influences the way individuals anticipate, react, and seek support when faced with chronic pain. Although cross-sectional research indicates that attachment insecurity and pain self-efficacy are associated with pain intensity in chronic pain populations, little is known about their long-term effects on pain, and about the directionality of associations between these constructs. Furthermore, whereas attachment is a relational concept, few studies on genito-pelvic pain have espoused a couples' perspective.
Learn More >Evidence suggests there to be an association between chronic pain and disruption of the body schema. We tested the hypothesis in fibromyalgia syndrome.
Learn More >Our knowledge of central sensitization (CS) in chronic low back pain (CLBP) is limited. 2011 fibromyalgia criteria and severity scales (2011 FM survey) has been used to determine FM positive as a surrogate of CS. The major features of CS including widespread hyperalgesia and dysfunction of the descending inhibitory pathways can be identified by pressure pain threshold (PPT) and conditioned pain modulation (CPM) tests. The purpose of the study was to examine neurophysiological characteristics and psychosocial symptoms in a subgroup of FM positive CLBP compared to FM negative CLBP patients.
Learn More >The alpha 7 nicotinic acetylcholine receptor, α7 nAChR, plays a central role in regulating inflammatory responses. Previous studies showed that pharmacological inhibitors of α7nAChR have a pro-inflammatory effect, increasing the circulating levels of cytokines such as tumor necrosis factor alpha (TNFα). This study focused on how genetic polymorphisms of the partially duplicated α7nAChR gene (CHRFAM7A), which is highly expressed in peripheral blood cells, contribute to functional outcome after spinal cord injury (SCI). In a cohort of 27 SCI patients and 25 emergency room consented controls (% F/M: 15/85; 24/76, mean ± SE age: 35 ± 1.38 and 35 ± 2.0 respectively), a panel of circulating cytokines, noradrenergic metabolite (normetanephrine [NMN]) levels, and clinical data were available within the first 7 days post-injury (DPI) up to 90 DPI, and were investigated in the acute/subacute (DPI 1-21) and intermediate (DPI 22-90) temporal periods. Cytokine and NMN plasma levels on different DPI were analyzed as a function of CHRFAM7A genotype. TNFα levels, as a representative of some elevated inflammatory mediators, were nearly 3-fold higher in individuals carrying the del2bp variant of the CHRFAM7A gene compared to that in the no deletion genotype (p = 0.001 ANOVA) 3-wks DPI, and 2-fold higher than genotype matched acute/subacute non-SCI injury controls within 7 days DPI. In contrast, NMN levels were initially unchanged, although after three weeks, NMN levels were significantly decreased in SCI individuals carrying the del2bp variant compared to non-carriers (p = 0.011 ANOVA). Numeric pain scores over this same period post-injury were significantly elevated in SCI patients carrying the del2bp variant relative to non-carriers (p = 0.001 ANOVA). Taken together, these data reveal that pro-inflammatory responses associated with CHRFAM7A gene variation may also be associated with differences in pain experience in patients following SCI, at least during the intermediate phase.
Learn More >Fibromyalgia (FM) is a prevalent chronic pain disorder associated with large suffering and substantial societal costs. Pain-related avoidance behaviour and hypervigilance to bodily symptoms are common in FM and contribute in maintaining and exacerbating the disorder. Exposure therapy targeting avoidance behaviours and hypervigilance has shown promise in the treatment of FM. The present study investigated mediators of treatment outcome in exposure therapy for FM. We used data from a randomised trial, where 140 participants were allocated to 10-week internet-delivered exposure therapy or to a waiting-list control condition. The main outcome variable (FM symptoms) and the hypothesized mediators (FM-related avoidance behaviour, mindful non-reactivity and FM-related worry) were measured weekly throughout treatment. Mediation analyses were conducted using linear mixed effects models with bootstrap replication and time-lagged analysis. Results indicated that all three process variables were significant mediators of FM severity. However, in the time-lagged analyses, only FM-related avoidance behaviour displayed a unidirectional relationship over time with FM symptoms, suggesting a causal effect. Thus, results illustrate that changes in avoidance behaviour mediate the outcome of exposure on FM symptoms, which implies that avoidance behaviour is an important treatment target in exposure therapy.
Learn More >Non-specific chronic low back pain (NSCLBP) patients present with reduced back extensor muscle endurance which could be explained by the higher fatigability of their lumbar muscles. However, studies investigating lumbar muscle fatigability have shown contradictory findings. Furthermore, none investigated potential asymmetry in lumbar muscle fatigability, despite neuromuscular asymmetry being reported as a risk factor for NSCLBP. The present study's primary purpose was to determine whether NSCLBP patients presented with higher lumbar muscle fatigability and fatigability asymmetry than asymptomatic participants.
Learn More >To investigate changes in whole body pain during urologic chronic pelvic pain syndrome (UCPPS) flares.
Learn More >