BACKGROUND: Few neuroimaging studies have investigated structural brain differences associated with variations in pain distribution.
OBJECTIVE: To explore structural differences of the brain in fibromyalgia (FM), temporomandibular disorder pain (TMD) and healthy pain-free controls (CON) using structural and diffusion MRI.
METHODS: A case-control exploratory study with three study groups with different pain distribution were recruited: FM (n = 16; mean age [standard deviation]: 44 [14] years), TMD (n = 17, 39 [14] years) and CON (n = 10, 37 [14] years). Participants were recruited at the University Dental Clinic in Malmö, Sweden. T1-weighted and diffusion MRIs were acquired, clinical and psychosocial measures were obtained. Main outcome measures were subcortical volume, cortical thickness, white matter microstructure and whole brain grey matter intensity.
RESULTS: Patients with FM had smaller volume in the right thalamus than patients with TMD (p = .020) and CON (p = .030). The right thalamus volume was negatively correlated to pain intensity (r = -0.37, p = .022) and pain-related disability (r = -0.45, p = .004). The FM group had lower cortical thickness in the right anterior prefrontal cortex than CON (p = .005). Cortical thickness in this area was negatively correlated to pain intensity (r [37] = - 0.48, p = .002).
CONCLUSIONS: This study suggests that thalamus grey matter alterations are associated with FM and TMD, and that anterior prefrontal cortex grey matter alterations are associated with FM but not TMD. Studies on chronic overlapping pain conditions are needed in relation to possible nociplastic pain mechanisms in the brain and central nervous system.

The nociceptive withdrawal reflex (NWR) is a protective limb withdrawal response triggered by painful stimuli, used to assess spinal nociceptive excitability. Conventionally, the NWR is understood as having two reflex responses: a short-latency Aβ-mediated response, considered tactile, and a longer-latency Aδ-mediated response, considered nociceptive. However, nociceptors with conduction velocities similar to Aβ tactile afferents have been identified in human skin. In this study, we investigated the effect of a preferential conduction block of Aβ fibers on pain perception and NWR signaling evoked by intradermal electrical stimulation in healthy participants. We recorded a total of 198 NWR responses in the intact condition, and no dual reflex responses occurred within our latency bandwidth (50-150 ms). The current required to elicit the NWR was higher than the perceptual pain threshold, indicating that NWR did not occur before pain was felt. In the block condition, when the Aβ-mediated tuning fork sensation was lost while Aδ-mediated nonpainful cooling was still detectable (albeit reduced), we observed that the reflex was abolished. Further, short-latency electrical pain intensity at pre-block thresholds was greatly reduced, with any residual pain sensation having a longer latency. Although electrical pain was unaffected at suprathreshold current, the reflex could not be evoked despite a two-fold increase in the pre-block current and a five-fold increase in the pre-block pulse duration. These observations lend support to the possible involvement of Aβ-fiber inputs in pain and reflex signaling.

OBJECTIVE: Postpartum depressive symptoms may be more prevalent and/or severe in vulnerable populations.
BACKGROUND: Postpartum depression represents a serious mental health problem associated with maternal suffering. Despite the relevance and clinical implications of investigating pain during pregnancy and the association with postpartum depression, there is limited research on this topic.
OBJECTIVE: We evaluated the association between pain during pregnancy and postpartum depression symptoms in adolescent and adult women.
METHODS: This study included 86 pregnant women (42 adolescents aged 13 to 18 years and 44 adults aged 23 to 28 years) from Trairi region, Northeastern Brazil. The evaluation of pain intensity and postpartum depression symptoms was conducted using the validated instruments of the Pelvic Pain Assessment Form and Edinburgh Postnatal Depression Scale (EPDS), respectively. Mann-Whitney and Kruskal-Wallis tests compared depressive symptoms in relation to pain status.
RESULTS: Overall, pregnant women reporting moderate to intense pain presented more depressive symptoms, with emphasis to \"deep pain with intercourse\" (p = .09), \"burning vaginal pain after sex\" (p = .01), \"pelvic pain lasting hours or days after intercourse\" (p = .06), and \"pain with urination\" (p = .09). When stratified by age group, significant associations were found only for the adolescents.
CONCLUSIONS: Our results suggest that women reporting pain in different daily situations have higher EPDS scores.
CONCLUSIONS: Pain during pregnancy is associated with postpartum depression symptoms, mainly among adolescents. Adequate screening and pain management during pregnancy may improve women\'s quality of life.

<b>Introduction:</b> Previous studies indicate a significant role of the inflammatory response in the etiopathogenesis of peripheral artery disease (PAD) and chronic pain (CP).<b>Aim:</b> The aim of the study was to determine the relationship between the concentration of SP and the level/concentration of inflammatory mediators (pro-inflammatory cytokines, positive and negative acute phase protein, anti-inflammatory cytokines) and pain intensity in people suffering from chronic pain (CP) in the course of PAD.<b>Material and methods:</b> We examined 187 patients of the Department of Vascular Surgery. As many as 92 patients with PAD and CP (study group) were compared to 95 patients with PAD without CP (control group). The relationship between SP and the level/concentration of fibrinogen, C-reactive protein (CRP), antithrombin III (AT), serum albumin, interleukin 10 (IL-10), tumor necrosis factor alpha (TNF-α) and pain intensity (Numeric Rating Scale; NRS) was analyzed. Statistical analysis was performed using the R program, assuming the level of statistical significance of α = 0.05.<b>Results:</b> Patients with CP had significantly higher levels of fibrinogen (P < 0.001), CRP (P < 0.001), SP (P < 0.001), IL-10 (P < 0.001), and lower serum albumin levels (P < 0.023). Higher SP concentration was associated with higher levels of IL-10, CRP, and pain intensity. In both groups, SP concentration correlated negatively with the level of fibrinogen (P < 0.001) as well as with albumin in the control group (P < 0.001).<b>Conclusions:</b> Thus, there is a relationship between the concentration of SP and fibrinogen, along with CRP, IL-10, and the intensity of pain in people suffering from CP in the course of PAD, and the level of albumin in the group without CP.

OBJECTIVE: Studies usually investigate a limited number or a predefined combinations of risk factors for sickness absence in employees with pain. We examined frequently occurring combinations across a wide range of work-related factors and pain perceptions.
METHODS: Cross-sectional study.
METHODS: Belgian companies that are under supervision of IDEWE, an external service for prevention and protection at work.
METHODS: In total, 249 employees experiencing pain for at least 6 weeks were included and filled out an online survey.
RESULTS: Latent profile analysis was used to differentiate profiles of work-related factors (physical demands, workload, social support and autonomy) and pain perceptions (catastrophising, fear-avoidance beliefs and pain acceptance). Subsequently, profiles were compared on sociodemographics (age, gender, level of education, work arrangement, duration of complaints, multisite pain and sickness absence in the previous year) and predictors of sickness absence (behavioural intention and perceived behavioural control).
RESULTS: Four profiles were identified. Profile 1 (38.2%) had favourable scores and profile 4 (14.9%) unfavourable scores across all indicators. Profile 2 (33.3%) had relatively high physical demands, moderate autonomy levels and favourable scores on the other indicators. Profile 3 (13.7%) showed relatively low physical demands, moderate autonomy levels, but unfavourable scores on the other indicators. Predictors of profiles were age (OR 0.93 and 95% CI (0.89 to 0.98)), level of education (OR 0.28 and 95% CI (0.1 to 0.79)) and duration of sickness absence in the previous year (OR 2.29 and 95% CI (0.89 to 5.88)). Significant differences were observed in behavioural intention (χ2=8.92, p=0.030) and perceived behavioural control (χ2=12.37, p=0.006) across the four profiles.
CONCLUSIONS: This study highlights the significance of considering the interplay between work-related factors and pain perceptions in employees. Unfavourable scores on a single work factor might not translate into maladaptive pain perceptions or subsequent sickness absence, if mitigating factors are in place. Special attention must be devoted to employees dealing with unfavourable working conditions along with maladaptive pain perceptions. In this context, social support emerges as an important factor influencing sickness absence.

Background: Virtual reality (VR) emerges as a promising non-pharmacological intervention for managing symptoms and providing distraction during chemotherapy. This study aims to assess VR\'s effectiveness on cancer-related symptoms, vital signs, and the patients\' perception of chemotherapy in lung cancer patients. Methods: A quasi-experimental study was conducted on 100 patients. Participants were allocated into an intervention group (n = 55), which experienced immersive VR, and a comparison group (n = 45), which received usual care. Data were collected through questionnaires and checklists, including feedback on the VR experience, pain, vital signs, and common cancer symptoms, assessed through the Edmonton Symptom Assessment Scale. Results: VR had a significant impact on reducing the perception of chemotherapy length. Patients reported high levels of satisfaction and tolerability. No adverse events were observed. VR did not have significant influence on pain intensity or vital signs. The only exceptions were oxygen saturation, where a significant difference (p = 0.02) was reported, and the perception of chemotherapy duration. Conclusions: As a non-pharmacological intervention, VR proves to be beneficial in minimizing the perceived length of chemotherapy sessions for lung cancer patients, enhancing their overall treatment experience. The intervention was found to be a safe, feasible, and well-accepted distraction technique. Future research should explore VR\'s potential effects on a wider range of symptoms and evaluate its impact on long-term outcomes.

Computer-controlled local anesthesia delivery (CCLAD) is an innovative electronic injection device that represents a cutting-edge approach to dental anesthesia. This system is promising for painless anesthesia using controlled anesthetic injections. This review aimed to compare the discomfort experienced by patients during local anesthesia using a traditional syringe and the CCLAD system and evaluate the potential of the CCLAD system as a painless dental anesthesia solution. The inclusion criteria for this study were based on the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. The study population, including children and adults, underwent dental anesthesia using the CCLAD system, ensuring a comprehensive and representative sample that instills confidence in the validity of the results. Fourteen clinical trials were included in the analysis after they fulfilled the eligibility criteria. We found that using computer-assisted anesthetic equipment not only led to a significantly lower pain perception score, but also had a profound positive impact on patient behavior. Patients using the CCLAD device exhibited more cooperative and helpful conduct, indicating the system\'s effectiveness in improving patient comfort and experience and reassuring the audience about its positive impact. In conclusion, using a computer-assisted anesthetic device such as the CCLAD system significantly reduced pain perception scores and improved patient behavior, making them more cooperative and helpful. These findings offer hope for pediatric dentistry and apprehensive adult patients, suggesting a more comfortable and less daunting dental experience with the CCLAD system.

Tactile and pain perception are essential for biological skin to interact with the external environment. This complex interplay of sensations allows for the detection of potential threats and appropriate responses to stimuli. However, the challenge is to enable flexible electronics to respond to mechanical stimuli such as biological skin, and researchers have not clearly reported the successful integration of somatic mechanical perception and sensation management functions into neuro-like electronics. In this work, an afferent nerve-like device with a pressure sensor and a perception management module is proposed. The pressure sensor comprises two conductive fabric layers and an ionic hydrogel, forming a capacitor structure that emulates the swift transition from tactile to pain perception under mechanical stimulation. Drawing inspiration from the neuronal \"gate control\" mechanism, the sensation management module adjusts signals in response to rubbing, accelerating the discharge process and reducing the perception duration, thereby replicating the inhibitory effect of biological neurons on pain following tactile interference. This integrated device, encompassing somatic mechanical perception and sensation management, holds promise for applications in soft robotics, prosthetics, and human-machine interaction.

Patients with Alzheimer\'s disease (AD) present with a variety of symptoms, including core symptoms as well as behavioral and psychological symptoms. Somatosensory neural systems are generally believed to be relatively unaffected by AD until late in the course of the disease; however, somatosensory perception in patients with AD is not yet well understood. One factor that may complicate the assessment of somatosensory perception in humans centers on individual variations in pathological and psychological backgrounds. It is therefore necessary to evaluate somatosensory perception using animal models with uniform status. In the current study, we focused on the hippocampus, the primary site of AD. We first constructed a rat model of AD model using bilateral hippocampal injections of amyloid-β peptide 1-40 and ibotenic acid; sham rats received saline injections. The Morris water maze test was used to evaluate memory impairment, and the formalin test (1 % or 4 % formalin) and upper lip von Frey test were performed to compare pain perception between AD model and sham rats. Finally, histological and immunohistochemical methods were used to evaluate tissue damage and neuronal activity, respectively, in the hippocampus. AD model rats showed bilateral hippocampal damage and had memory impairment in the Morris water maze test. Furthermore, AD model rats exhibited significantly less pain-related behavior in phase 2 (the last 50 min of the 60-minute observation) of the 4 % formalin test compared with the sham rats. However, no significant changes were observed in the von Frey test. Immunohistochemical observations of the trigeminal spinal subnucleus caudalis after 4 % formalin injection revealed significantly fewer c-Fos-immunoreactive cells in AD model rats than in sham rats, reflecting reduced neuronal activity. These results indicate that AD model rats with hippocampal damage have reduced responsiveness to persistent inflammatory chemical stimuli to the orofacial region.

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