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Attentional Bias Towards Visual Itch and Pain Stimuli in Itch- and Pain-free Individuals?

Itch and pain are important attention-demanding sensations that allow adaptive responses to potential bodily harm. An attentional bias towards itch and pain stimuli, i.e. preferential attention allocation towards itch- and pain-related information, has been found in healthy, as well as patient groups. However, it remains unclear whether attentional bias for itch and pain differs from a general bias towards negative information. Therefore, this study investigated attentional bias towards itch and pain in 70 itch- and pain-free individuals. In an attention task, itch- and pain-related stimuli, as well as negative stimuli, were presented alongside neutral stimuli. The results did not indicate an attentional bias towards itch-, pain-, and negative visual information. This finding suggests that people without itch and pain symptoms do not prioritize itch- and pain-related information above neutral information. Future research should investigate whether attention towards itch- and pain-related information might be biased in patients with chronic itch and pain.

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Structural MRI Analysis of Chronic Pain Patients Following Interdisciplinary Treatment Shows Changes in Brain Volume and Opiate-Dependent Reorganization of the Amygdala and Hippocampus.

The present study examined pre- to post-treatment changes in volumes for brain structures known to be associated with pain processing (thalamus, caudate, putamen, pallidum, hippocampus, amygdala, and accumbens) following an interdisciplinary pain management program.

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The Relationship Between the Pain Experience and Emotion Regulation in Older Adults.

To investigate the relationship of emotion regulation strategies (i.e., emotional suppression and reappraisal) with pain catastrophizing, fear of pain, pain intensity, worry, and depression as function of age in samples of older and younger adults.

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Clinical Validation of a Multi-Biomarker Assay for the Evaluation of Chronic Pain Patients in a Cross-Sectional, Observational Study.

Chronic pain assessment and post-treatment evaluation continues to be challenging due to a lack of validated, objective tools to measure patient outcomes. Validation of mechanistic pain biomarkers would allow clinicians to objectively identify abnormal biochemistry contributing to painful symptoms.

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Selected Ionotropic Receptors and Voltage-Gated Ion Channels: More Functional Competence for Human Induced Pluripotent Stem Cell (iPSC)-Derived Nociceptors.

Preclinical research using different rodent model systems has largely contributed to the scientific progress in the pain field, however, it suffers from interspecies differences, limited access to human models, and ethical concerns. Human induced pluripotent stem cells (iPSCs) offer major advantages over animal models, i.e., they retain the genome of the donor (patient), and thus allow donor-specific and cell-type specific research. Consequently, human iPSC-derived nociceptors (iDNs) offer intriguingly new possibilities for patient-specific, animal-free research. In the present study, we characterized iDNs based on the expression of well described nociceptive markers and ion channels, and we conducted a side-by-side comparison of iDNs with mouse sensory neurons. Specifically, immunofluorescence (IF) analyses with selected markers including early somatosensory transcription factors (BRN3A/ISL1/RUNX1), the low-affinity nerve growth factor receptor (p75), hyperpolarization-activated cyclic nucleotide-gated channels (HCN), as well as high voltage-gated calcium channels (VGCC) of the Ca2 type, calcium permeable TRPV1 channels, and ionotropic GABA receptors, were used to address the characteristics of the iDN phenotype. We further combined IF analyses with microfluorimetric Ca measurements to address the functionality of these ion channels in iDNs. Thus, we provide a detailed morphological and functional characterization of iDNs, thereby, underpinning their enormous potential as an animal-free alternative for human specific research in the pain field for unveiling pathophysiological mechanisms and for unbiased, disease-specific personalized drug development.

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Randomized Trial of General Strength and Conditioning Versus Motor Control and Manual Therapy for Chronic Low Back Pain on Physical and Self-Report Outcomes.

Exercise and spinal manipulative therapy are commonly used for the treatment of chronic low back pain (CLBP) in Australia. Reduction in pain intensity is a common outcome; however, it is only one measure of intervention efficacy in clinical practice. Therefore, we evaluated the effectiveness of two common clinical interventions on physical and self-report measures in CLBP. Participants were randomized to a 6‑month intervention of general strength and conditioning (GSC; = 20; up to 52 sessions) or motor control exercise plus manual therapy (MCMT; =20; up to 12 sessions). Pain intensity was measured at baseline and fortnightly throughout the intervention. Trunk extension and flexion endurance, leg muscle strength and endurance, paraspinal muscle volume, cardio‑respiratory fitness and self-report measures of kinesiophobia, disability and quality of life were assessed at baseline and 3- and 6-month follow-up. Pain intensity differed favoring MCMT between-groups at week 14 and 16 of treatment (both, = 0.003), but not at 6-month follow‑up. Both GSC (mean change (95%CI): -10.7 (-18.7, -2.8) mm; = 0.008) and MCMT (-19.2 (-28.1, -10.3) mm; < 0.001) had within-group reductions in pain intensity at six months, but did not achieve clinically meaningful thresholds (20mm) within- or between‑group. At 6-month follow-up, GSC increased trunk extension (mean difference (95% CI): 81.8 (34.8, 128.8) s; = 0.004) and flexion endurance (51.5 (20.5, 82.6) s; = 0.004), as well as leg muscle strength (24.7 (3.4, 46.0) kg; = 0.001) and endurance (9.1 (1.7, 16.4) reps; = 0.015) compared to MCMT. GSC reduced disability (-5.7 (‑11.2, -0.2) pts; = 0.041) and kinesiophobia (-6.6 (-9.9, -3.2) pts; < 0.001) compared to MCMT at 6‑month follow-up. Multifidus volume increased within-group for GSC ( = 0.003), but not MCMT or between-groups. No other between-group changes were observed at six months. Overall, GSC improved trunk endurance, leg muscle strength and endurance, self-report disability and kinesiophobia compared to MCMT at six months. These results show that GSC may provide a more diverse range of treatment effects compared to MCMT.

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Acupuncture Treatment Modulates the Connectivity of Key Regions of the Descending Pain Modulation and Reward Systems in Patients with Chronic Low Back Pain.

Chronic low back pain (cLBP) is a common disorder with unsatisfactory treatment options. Acupuncture has emerged as a promising method for treating cLBP. However, the mechanism underlying acupuncture remains unclear. In this study, we investigated the modulation effects of acupuncture on resting state functional connectivity (rsFC) of the periaqueductal gray (PAG) and ventral tegmental area (VTA) in patients with cLBP. Seventy-nine cLBP patients were recruited and assigned to four weeks of real or sham acupuncture. Resting state functional magnetic resonance imaging data were collected before the first and after the last treatment. Fifty patients completed the study. We found remission of pain bothersomeness in all treatment groups after four weeks, with greater pain relief after real acupuncture compared to sham acupuncture. We also found that real acupuncture can increase VTA/PAG rsFC with the amygdala, and the increased rsFC was associated with decreased pain bothersomeness scores. Baseline PAG-amygdala rsFC could predict four-week treatment response. Our results suggest that acupuncture may simultaneously modulate the rsFC of key regions in the descending pain modulation (PAG) and reward systems (VTA), and the amygdala may be a key node linking the two systems to produce antinociceptive effects. Our findings highlight the potential of acupuncture for chronic low back pain management.

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Determination of psychosocial factors in cluster headache – construction and psychometric properties of the Cluster Headache Scales (CHS).

Cluster headache (CH) is clinically associated with considerable psychosocial burden. However, instruments to assess and characterize psychosocial factors in cluster headache more specifically are lacking. This study aimed to develop a self-report questionnaire, which assesses the broadest possible spectrum of psychosocial factors in cluster headache, the Cluster Headache Scales (CHS).

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The Impact of Posttraumatic Stress Disorder on Clinical Presentation and Psychosocial Treatment Response in Youth with Functional Abdominal Pain Disorders: An Exploratory Study.

Youth with functional abdominal pain disorders (FAPDs) may report high rates of trauma and/or posttraumatic stress disorder (PTSD), which could impact both physical and psychosocial functioning, in addition to psychosocial treatment response. The current study aimed to examine the rates of PTSD in a sample of 89 youth with FAPDs and examine the association between PTSD with physical and psychosocial functioning. The impact of PTSD on psychosocial treatment response in a subsample of youth with FAPDs was also explored. Participants were youth with FAPDs (ages 9-14) enrolled in a larger study examining the effect of a short-term pain and anxiety focused cognitive behavioral therapy (CBT) treatment (Aim to Decrease Anxiety and Pain Treatment (ADAPT)) for youth with FAPDs. Youth were administered a semi-structured diagnostic interview by a trained clinician to confirm the presence of psychological diagnoses, including PTSD. Measures of physical and psychosocial functioning were also completed. Results revealed a high rate of PTSD in youth with FAPDs with 12.4% meeting diagnostic criteria for the disorder. PTSD was associated with several indicators of increased psychosocial impairment and one indicator of physical impairment. Exploratory analyses revealed comorbid PTSD may impact response to a brief CBT intervention targeting pain and anxiety, but more rigorous controlled studies are needed.

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Quantitative Sensory Testing in Adolescents with Co-occurring Chronic Pain and Obesity: A Pilot Study.

Factors such as gender, ethnicity, and age affect pain processing in children and adolescents with chronic pain. Although obesity has been shown to affect pain processing in adults, almost nothing is known about pediatric populations. The aim of this pilot study was to explore whether obesity alters sensory processing in adolescents with chronic pain. Participants were recruited from a chronic pain clinic (Chronic Pain (CP), = 12 normal weight; Chronic Pain + Obesity (CPO), = 19 overweight/obesity) and from an obesity clinic (Obesity alone (O), = 14). The quantitative sensory testing protocol included assessments of thermal and mechanical pain thresholds and perceptual sensitization at two sites with little adiposity. The heat pain threshold at the hand was significantly higher in the CPO group than in either the CP or O groups. Mechanical pain threshold (foot) was significantly higher in the CPO group than the CP group. No differences were found on tests of perceptual sensitization. Correlations between experimental pain and clinical pain parameters were found for the CPO group, but not for the CP group. This preliminary study provides important lessons learned for subsequent, larger-scale studies of sensory processing for youth with co-occurring chronic pain and obesity.

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