Pain Intensity In Individuals Research Articles

Clustering and Interpretation of time-series trajectories of chronic pain using evidential c-means

The most well-known unsupervised classification algorithms allow for the identification of hard or probabilistic partitions. However, when working with complex datasets such as those found in the healthcare domain, it is important to note that these partitions may have limitations, particularly when considering the uncertainty associated with medical data. Indeed, these algorithms do not account for modeling outliers, imprecise, or uncertain observations. In this study, we focused on analyzing time series of barometers attributes related to pain intensity in individuals with chronic pain. Our goal was to identify different typologies of care trajectories, highlighting distinct trajectories of chronic pain through clustering techniques. We propose a soft clustering approach based on feature extraction and selection from sequential data, aiming to improve interpretability and enhance the performance of the clustering procedure. Time series feature extraction and selection effectively handles complex and noisy data, improving interpretability and clustering performance. Evidential soft clustering models data uncertainty and imprecision, providing a better representation of nuances and variations in complex, raw data. The first step involves extracting features from the available time series and selecting the most important attributes. For this purpose, we use a time series feature extractor (Tsfresh) and unsupervised feature selection methods, including unsupervised Random Forest, Laplacian Score, and unsupervised Spectral Feature Selection. The second step involves using the evidential c-means (ECM) clustering algorithm on the extracted attributes. The ECM method, based on belief functions, allows for generating a credal partition that has the ability to model various forms of uncertainty. This partition can then be transformed into a hard partition to study individuals based on this uncertainty criterion. The results reveal the existence of two clusters of chronic pain related to discomfort and well-being, exhibiting excellent separability and compactness. Additionally, an uncertain cluster emerges grouping patients with intermediate characteristics. The interpretability of the determined partitions through descriptive analysis, statistical tests, and repeated measures multinomial regression on clinical and demographic data allowed us to determine the profile of patients in the identified trajectories.

Altered Corticobrainstem Connectivity during Spontaneous Fluctuations in Pain Intensity in Painful Trigeminal Neuropathy.

Chronic neuropathic pain can result from nervous system injury and can persist in the absence of external stimuli. Although ongoing pain characterizes the disorder, in many individuals, the intensity of this ongoing pain fluctuates dramatically. Previously, it was identified that functional magnetic resonance imaging signal covariations between the midbrain periaqueductal gray (PAG) matter, rostral ventromedial medulla (RVM), and spinal trigeminal nucleus are associated with moment-to-moment fluctuations in pain intensity in individuals with painful trigeminal neuropathy (PTN). Since this brainstem circuit is modulated by higher brain input, we sought to determine which cortical sites might be influencing this brainstem network during spontaneous fluctuations in pain intensity. Over 12 min, we recorded the ongoing pain intensity in 24 PTN participants and classified them as fluctuating (n = 13) or stable (n = 11). Using a PAG seed, we identified connections between the PAG and emotional-affective sites such as the hippocampal and posterior cingulate cortices, the sensory-discriminative posterior insula, and cognitive-affective sites such as the dorsolateral prefrontal (dlPFC) and subgenual anterior cingulate cortices that were altered dependent on spontaneous high and low pain intensity. Additionally, sliding-window functional connectivity analysis revealed that the dlPFC-PAG connection anticorrelated with perceived pain intensity over the entire 12 min period. These findings reveal cortical systems underlying moment-to-moment changes in perceived pain in PTN, which likely cause dysregulation in the brainstem circuits previously identified, and consequently alter the appraisal of pain across time.

Effects of Respiratory Muscle Training on Functional Ability, Pain-Related Outcomes, and Respiratory Function in Individuals with Low Back Pain: Systematic Review and Meta-Analysis.

Objectives: The aim of this meta-analysis was to determine the effects of respiratory muscle training (RMT) on functional ability, pain-related outcomes, and respiratory function in individuals with sub-acute and chronic low back pain (LBP). Methods: The study selection was as follows: (participants) adult individuals with >4 weeks of LBP; (intervention) RMT; (comparison) any comparison RMT (inspiratory or expiratory or mixed) versus control; (outcomes) postural control, lumbar disability, pain-related outcomes, pain-related fear-avoidance beliefs, respiratory muscle function, and pulmonary function; and (study design) randomized controlled trials. Results: 11 studies were included in the meta-analysis showing that RMT produces a statistically significant increase in postural control (mean difference (MD) = 21.71 [12.22; 31.21]; decrease in lumbar disability (standardized mean difference (SMD) = 0.55 [0.001; 1.09]); decrease in lumbar pain intensity (SMD = 0.77 [0.15; 1.38]; increase in expiratory muscle strength (MD = 8.05 [5.34; 10.76]); and increase in forced vital capacity (FVC) (MD = 0.30 [0.03; 0.58]) compared with a control group. However, RMT does not produce an increase in inspiratory muscle strength (MD = 18.36 [-1.61; 38.34]) and in forced expiratory volume at the first second (FEV1) (MD = 0.36 [-0.02; 0.75]; and in the FEV1/FVC ratio (MD = 1.55 [-5.87; 8.96]) compared with the control group. Conclusions: RMT could improve expiratory muscle strength and FVC, with a moderate quality of evidence, whereas a low quality of evidence suggests that RMT could improve postural control, lumbar disability, and pain intensity in individuals with sub-acute and chronic LBP. However, more studies of high methodological quality are needed to strengthen the results of this meta-analysis.

Psychological treatments for temporomandibular disorder pain-A systematic review.

Temporomandibular disorders (TMD) are common. They affect abilities for carrying out daily tasks and influence different psychological aspects. In addition to standard treatment, psychological treatments have been suggested. The aim was to investigate the effects of psychological treatments on patients with painful TMD in a short- and long-term perspective. An electronic search was conducted in the databases MEDLINE, CINAHL, EMBASE, the Cochrane Central Registry of Controlled Trials (CENTRAL), and Web of Science for randomized clinical trials (RCTs) reporting psychological interventions for TMD. Registered beforehand in PROSPERO (CRD42022320106). In total, 18 RCTs were included; six RCTs that could be used in the meta-analysis, and all 18 RCTs were used in the narrative synthesis. Risk of bias was assessed by the Cochrane's tool for assessing risk of bias and certainty of evidence by GRADE. The narrative synthesis indicates that psychological treatment options seem equivalent to standard treatment for painful TMD. The meta-analysis showed that a combination of psychological treatment and standard treatment and manual treatment (very low-quality evidence) are significantly better in pain reduction than just counselling and standard treatments of TMD. This study indicates that psychological treatments seem to reduce pain intensity in individuals with painful TMD, and that the effect seems to be equally good as standard treatment. However, a combination of psychological treatments and standard treatments seems to have an even better effect. This indicates that psychological treatments are promising as an additional treatment approach for painful TMDs.

Effects of foam roller on pain intensity in individuals with chronic and acute musculoskeletal pain: a systematic review of randomized trials

ObjectiveTo analyze the effects of using foam roller on pain intensity in individuals with chronic and acute musculoskeletal pain.MethodsThis systematic review was registered in the National Institute for Health Research’s prospective online registry of systematic reviews (PROSPERO) under CRD42023456841. The databases Pubmed, Medline (via Ovid), Embase, BVS, and PEDro (Physiotherapy Evidence Database) were consulted to carry out this systematic review. Notably, the records of clinical trials characterized as eligible were manually searched. The search terms were: (foam rolling OR foam rolling vibration) AND (acute musculoskeletal pain) AND (chronic musculoskeletal pain). The search was performed until August 22, 2023. For the analysis of the methodological quality, the PEDro scale was used for each of the manuscripts included in the systematic review. Due to the heterogeneity in the studies included in this systematic review, performing a meta-analysis of the analyzed variables was impossible.ResultsOnly six manuscripts were eligible for data analysis. The type of FR used was non-vibrational, being applied by a therapist in only one of the manuscripts. With an application time ranging from at least 45 s to 15 min, the non-vibrational FR was applied within a day up to six weeks. Using the PEDro scale, scores were assigned that varied between 4 and 8 points, with an average of 6 ± 1.29 points. Only two randomized clinical trials found a significant benefit in pain intensity of adding FR associated with a therapeutic exercise protocol in individuals with patellofemoral pain syndrome and chronic neck pain.ConclusionThe results of this systematic review do not elucidate or reinforce the clinical use of FR in pain intensity in individuals with chronic and acute musculoskeletal pain.

Mindfulness-based Interventions for Chronic Low Back Pain: A Systematic Review and Meta-analysis.

This systematic review aimed to compile existing evidence examining the effects of mindfulness-based interventions (MBIs) for chronic low back pain (CLBP). CLBP leads to millions of disabled individuals in the United States each year. Current pharmacologic treatments are only modestly effective and may present long-term safety issues. MBIs, which have an excellent safety profile, have been shown in prior studies to be effective in treating CLBP yet remained underutilized. Ovid/Medline, PubMed, Embase, and the Cochrane Library were searched for randomized controlled trials (RCTs), pilot RCTs, and single-arm studies that explored the effectiveness of MBIs in CLBP. Separate searches were conducted to identify trials that evaluated MBIs in reducing pain intensity in individuals with CLBP. A meta-analysis was then performed using R v3.2.2, Metafor package v 1.9-7. Eighteen studies used validated patient-reported pain outcome measures and were therefore included in the meta-analysis. The MBIs included mindfulness meditation, mindfulness-based stress reduction, mindfulness-based cognitive therapy, mindfulness-oriented recovery enhancement, acceptance and commitment therapy, dialectical behavioral therapy, meditation-cognitive behavioral therapy, mindfulness-based care for chronic pain, self-compassion course, and loving-kindness course. Pain intensity scores were reported using a numerical rating scale (0 to 10) or an equivalent scale. The meta-analysis revealed that MBIs have a beneficial effect on pain intensity with a large-sized effect in adults with CLBP. MBIs seem to be beneficial in reducing pain intensity. Although these results were informative, findings should be carefully interpreted due to the limited data the high variability in study methodologies, small sample sizes, inclusion of studies with high risk of bias, and reliance on pre-post treatment differences with no attention to maintenance of effects. More large-scale RCTs are needed to provide reliable effect size estimates for MBIs in persons with CLBP.

Assessing pain intensity in patients undergoing orthodontic treatment with fixed appliances: A systematic review

Orthodontic treatment commonly induces pain in a significant majority of patients, ranging from ninety to ninety-five percent. This study aimed to systematically review and assess the intensity of orthodontic pain associated with fixed appliances. A comprehensive search was conducted on Pubmed and Hinari databases, as well as orthodontic journal sites, spanning from March to May 2021. Articles reporting on pain intensity in individuals undergoing labial fixed orthodontic treatment were meticulously selected using specific keywords. The Visual Analog Scale was employed to evaluate pain intensity, and each included article underwent a rigorous evaluation based on essential criteria for scientific writing. Data compilation and analysis were performed using SPSS software. The findings revealed a mean pain intensity of 20.2 mm ± 15.8 across the general study population, with a minimum intensity of 0.2 mm and a maximum of 63.2 mm. Effective communication by practitioners, preemptively addressing and explaining the anticipated discomfort and pain during treatment, results in a reduced need for analgesics.

Real time ultrasound imaging shows changes in deep neck flexor activation during exercise in individuals with mechanical neck pain.

Deep neck flexor muscle atrophy and increased superficial neck muscle activation are associated with disability and pain intensity in individuals with neck pain. There is a lack of evidence to support direct assessment of deep neck flexor muscles in a non-invasive way during exercise performance to help determine the effectiveness of different neck strengthening exercises. Compare longus colli (LC) and sternocleidomastoid (SCM) activation between individuals with and without neck pain using real time ultrasound (RTUS) during a series of craniocervical exercises. This cross-sectional cohort study recruited 10 control and 10 neck pain participants to complete four deep neck flexor activation activities involving varying levels of craniocervical flexion. Dimensions of the LC and SCM were measured using RTUS at rest and during exercise. Independent t-tests assessed baseline differences and analysis of variance examined activation changes. At rest, the neck pain group had significantly smaller cross-sectional area and thickness of the LC compared to the control group (p< 0.05). During exercise, the neck pain group showed significantly larger increases in LC thickness and cross-sectional area across exercise compared to the control group, with no differences in SCM activation between groups. Despite atrophy, individuals with neck pain can activate their deep neck flexor muscles appropriately without activating their superficial neck flexor muscles in a supine series of craniocervical flexion exercise as measured by non-invasive ultrasound imaging.

Exercise prescription variables predict reductions in pain intensity in adults with chronic low back pain: secondary analysis of a randomised controlled trial

ObjectivesThe relationship between exercise training variables and clinical outcomes in low back pain (LBP) is unclear. The current study aimed to explore the relationship between exercise training parameters and pain...

Effect of osteopathic visceral manipulation for individuals with functional constipation and chronic nonspecific low back pain: Randomized controlled trial

ObjectiveTo investigate the effect of osteopathic visceral manipulation (OVM) on disability and pain intensity in individuals with functional constipation and chronic nonspecific low back pain. MethodsThis study is a randomized controlled trial with a blinded assessor. Seventy-six volunteers with functional constipation and chronic nonspecific low back pain were randomized to two groups: OVM and sham OVM. The primary clinical outcome was pain intensity measured using a numeric rating scale (NRS) and disability measured using the Oswestry Disability Index (ODI). The secondary outcomes were electromyographic signals measured during the flexion-extension cycle, the finger-to-floor distance during complete flexion of the trunk and the Fear-Avoidance Beliefs Questionnaire (FABQ). All outcomes were determined after six weeks of treatment as well as three months after randomization. ResultsThe OVM group reported a reduction in pain intensity after six weeks of treatment and at the three-month evaluation (p < .0002) and the sham group reported a reduction in pain intensity after three-month evaluation (p < .007). For the ODI was also found in the OVM group six weeks after the end of treatment (treatment effect = −6.59, 95% CI: −12.01 to −1.17, p = .01) and at the three-month evaluation (treatment effect = −6.02, 95% CI: −11.55 to −0.49, p = .03). Significant differences were also found for paravertebral muscle activity during the dynamic phases (flexion and extension) six-week evaluations. ConclusionsThe OVM group demonstrated a reduction in pain intensity and improvement in disability after six-weeks and three-month follow-up while the sham group reduction in pain three-month follow-up.

Study of the polymorphism of the ADRB2 molecular structure and its influence on the development of chronic postsurgical pain in children

Introduction. Pain is a signal to any aggression that leads to cellular damage and requires a defensive response. Uncontrolled acute perioperative visceral pain can lead to the development of pain chronicity. By studying the characteristics of chronic pain, some scientists have identified relationships with single-nucleotide polymorphisms of the beta2-adrenergic receptor (ADRB2) gene. Purpose - to study the dependence of pain expression in the postoperative period in children on the polymorphism of the molecular structure of the ADRB2 receptor. Materials and methods. The study involved 42 children (20 boys and 22 girls) aged 7 to 18 years who were treated in the surgical department in 2020-2022 for acute appendicitis and peritonitis. Results. Based on the results of examining all the subjects under study, 13 children had the Arg16Gly polymorphism, 15 children had the Arg16Gly polymorphic variant, and 14 children were diagnosed with the homomorphic Gly16Gly polymorphism in the ADRB2. The data obtained confirmed the trend of the preliminary analysis and proved better body response to pain relief and reduced pain intensity in individuals with the Arg16Arg variant of the ADRB2. Analysis of the dependence between the polymorphism of the ADRB2 molecular structure and Visual Analogue Scale (VAS) scores in children in the postoperative period proved that the presence of Arg in the receptor phenotype had a strong negative correlation with the VAS score on discharge day (r=-0.822, p&lt;0.001), while the presence of Gly in the receptor phenotype had a strong positive correlation with the Visual Analogue Scale score on discharge day (r=0.814, p&lt;0.001). In regression analysis, the presence of Gly in the receptor phenotype was associated with a 1.917-fold increase in the VAS score at hospital discharge (OR: 1.917; 95% CI: 1.448-2.385; р&lt;0.001). Conclusions. The presence of the homomorphic Arg16Arg variant of the ADRB2 in children who underwent anterior abdominal wall surgery was accompanied by rapid response to analgesics. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of the participating institution. The informed consent of the patient was obtained for conducting the studies. No conflict of interests was declared by the authors.

A Systematic Review and Meta-Analysis Protocol on How Best to Use Non-Pharmacologic Therapies to Manage Chronic Low Back Pain and Associated Depression.

To evaluate the efficacy of different non-pharmacologic therapies (NPTs) on relieving depressive symptoms and pain intensity in individuals living with chronic low back pain (LBP) and associated depression. A comprehensive search of seven English databases and two Chinese databases from inception to the search date will be undertaken. The reference lists of previously published relevant reviews and included trials will also be searched. Only peer-reviewed and published moderate-to-high quality randomized controlled trials (RCTs) for chronic LBP and associated depression treated with NPTs will be considered. Two independent reviewers will identify studies, extract data, assess risk of bias, and evaluate the strength of evidence using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. Meta-analysis will be conducted to estimate the treatment effect of various NPTs. Heterogeneity will be assessed using Cochrane's Q and the I-squared statistics. Subgroup and sensitivity analyses will be performed to assess the robustness of findings. A funnel plot will be developed to evaluate reporting bias, and Begg's and Egger's tests will be used to assess funnel plot symmetries. This protocol outlines the planned scope and methodology for an upcoming systematic review and meta-analysis, which will provide up-to-date evidence on 1) which NPTs are associated with improvements in depressive symptoms and pain intensity and 2) whether the effects of NPTs on chronic LBP and associated depression vary according to clinical condition, participant, and treatment characteristics. Our meta-analyses of moderate-to-high quality RCTs will help to develop specific recommendations on prescribing NPTs in patients with chronic LBP and associated depression. This protocol is registered on the International Platform of Registered Systematic Review and Meta-analysis (INPLASY) protocols platform as record No. INPLASY202260055.

Evaluating Associations between Average Pain Intensity and Genetic Variation in People with Sickle Cell Disease: An Exploratory Study

BackgroundPain is one of the most common and deleterious symptoms experienced by individuals with sickle cell disease (SCD). There is a paucity of studies identifying potential genetic mechanisms of pain in this population. AimExamine associations between 11 functional single nucleotide polymorphisms in 9 candidate genes with reports of average pain intensity in individuals with sickle cell disease. MethodCross-sectional analyses were performed on data and blood samples collected through the Duke SCD Implementation Consortium Registry. Participants were asked to rate their pain “on the average” using an 11-point numeric rating scale (0 = no pain; 10 = pain as bad as you can imagine). We genotyped 11 single nucleotide polymorphisms in 9 pain-related genes using TaqMan® Genotyping Assays. Associations between each polymorphism and reports of average pain were evaluated. ResultsThe 86 participants (mean age: 28.7 years; 64% female) included in this study reported moderate pain on average (Mean = 4, Standard Deviation = 2.4). ICAM1 rs1799969 was the only genetic polymorphism that was significantly associated with pain (p = .01). Individuals with one or more minor alleles had lower average pain (Mean = 1.25, Standard Deviation = 1.50) than individuals without a minor allele (Mean = 4.13, Standard Deviation = 2.25). The effect size for ICAM1 rs1799969 was 1.30, which is considered large. The effect sizes for all other single nucleotide polymorphisms ranged from small to medium (range: 0–0.3). ConclusionsOur findings provide preliminary evidence that the minor allele in ICAM1 rs1799969 had protective effects against experiencing more severe pain in sickle cell disease.

Clinical course of pain intensity in individuals with cerebral palsy: A prognostic systematic review.

To describe the clinical course of pain intensity in individuals with cerebral palsy (CP) resulting from usual care or specific interventions. We conducted an exploratory prognostic systematic review searching electronic databases from inception to 31st December 2021. Evidence from low and moderate risk-of-bias studies was synthesized. We retrieved 2275 citations; 18 studies met the inclusion criteria and 10 were synthesized. The course of pain intensity in children with CP receiving usual care was stable over 15 weeks (χ2 [2] =1.8, p=0.5). Children who received continuous intrathecal baclofen (CITB) reported significant pain intensity reduction (visual analogue scale [VAS]=-4.2 out of 10, 95% confidence interval [CI]=-6.3 to -2.1]) 6 months postinsertion but similar children receiving usual care had no significant change over 6 months (VAS=1.3 out of 10, 95% CI=-1.3 to 3.6). Children receiving botulinum neurotoxin A (BoNT-A) injections had significant decreases in pain after 1 month (numeric rating scale=-6.5, 95% CI=-8.0 to -5.0). Adults with chronic pain receiving usual care reported stable pain intensity over time; pain intensity improved in ambulatory adults exercising and those treated surgically for cervical myelopathy. The course of pain intensity in individuals with CP is unclear. Evidence suggests that children and adults receiving usual care had stable pain intensity over the short or long term. Interventions (CITB and BoNT-A in children and exercise and surgical treatment for cervical myelopathy in adults) had pain intensity reduction. Larger study samples are needed to confirm these results. Pain intensity was stable in children with cerebral palsy (CP) receiving usual care. Adults with CP and chronic pain receiving usual care had stable, persistent pain intensity. Children receiving continuous intrathecal baclofen via pump and botulinum neurotoxin A reported significantly lower pain intensities. Adults with chronic pain and dyskinetic CP and cervical myelopathy reported significantly lower pain intensity with exercise or cervical decompression. Limited high-quality evidence exists describing non-procedural pain changes in individuals with CP.

Relationship between pressure and thermal pain threshold, pain intensity, catastrophizing, disability, and skin temperature over myofascial trigger point in individuals with neck pain

The objective of the study was to correlate the thermal pain threshold (heat and cold) on myofascial trigger points with measurements of pain and skin temperature in patients with chronic neck pain. This is a cross-sectional study. We included participants of both genders, aged between 18-45 years, with chronic neck pain (>90 days), and with active bilateral myofascial trigger point centrally located in the upper trapezius muscle. Neck Disability Index, Numerical Rating Scale, Pain-Related Catastrophizing Thoughts Scale, algometry, infrared thermography, and quantitative sensory testing were used for the evaluation. A significant, weak, and negative association was observed between pain intensity and heat pain threshold on the myofascial trigger point to the right (rho -0.381, p=0.022) and to the left (rho -0.334, p=0.049), and a significant, weak, and positive association was observed between pain intensity and cold pain threshold on the myofascial trigger point to the right (rho 0.471, p=0.004) and to the left (rho 0.339, p=0.043). Thermal pain threshold (heat and cold) on myofascial trigger points is associated with pain intensity in individuals with chronic neck pain.

Reduction in Pain and Pain Intensity with Nonpharmacological Treatment in Severely Obese Patients: A Randomized Clinical Trial.

The objective of this study was to analyze the effectiveness of two nonpharmacological interventions—traditional Brazilian diet (DieTBra), and extra-virgin olive oil (EVOO)—in terms of the reduction in pain and pain intensity in individuals with severe obesity. We conducted a 12-week parallel randomized clinical trial with 149 individuals (body mass index (BMI) ≥ 35 kg/m2) who were randomized into three groups: supplementation with EVOO (n = 50), DieTBra (n = 49), and EVOO + DieTBra (n = 50). Of the total, 133 individuals with a mean BMI of 46.04 kg/m2 completed the study. By the end of the follow-up, there was a reduction in severe pain in the EVOO + DieTBra group (p = 0.003). There was a significant reduction in severe pain in the EVOO + DieTBra group (−22.7%); pain in the wrist and hand (−14.1%), upper back (−26.9%), and knees (−18.4%) in the DieTBra group; and reduction in hip pain (−11.1%) with EVOO consumption. We conclude that EVOO and DieTBra, either alone or in combination, are effective interventions to reduce pain intensity and pain in different regions in individuals with severe obesity, and have great potential for clinical application.

Even mild catastrophic thinking is related to pain intensity in individuals with painful temporomandibular disorders.

Temporomandibular disorders (TMD) are often associated with psychological comorbidities. One such comorbidity is pain catastrophising, that is, exaggeration of negative consequences of a painful event. The aim was to investigate catastrophising in individuals with painful TMD compared to controls and the association between catastrophising and pain intensity, number of pain sites and functional limitations. A community-based sample of 110 individuals (83 women; 20-69yrs) with painful TMDs (myalgia/arthralgia as per Diagnostic Criteria for TMD) and 190 age- and gender-matched controls (119 women; 20-69yrs) from the Public Dental services in Västerbotten, Sweden, participated. Associations between catastrophising and functional jaw limitations, respectively, and painful TMD were evaluated with ordinal regression adjusted for the effect of gender and age. Associations (Spearman's correlation) of the Pain catastrophising Scale (PCS) with Jaw Functional Limitation Scale (JFLS-20), pain site number (whole-body pain map), and characteristic pain intensity (CPI) and intergroup comparisons (Mann-Whitney U test) of these variables were also calculated. Levels of catastrophising were associated with TMD pain (OR 1.6, 95%CI 1.1-2.6). Among individuals with painful TMD, catastrophising was correlated to pain intensity (r=0.458, p<0.01) and functional limitations (r=0.294-0.321, p≤0.002), but not to number of pain sites. Compared to controls, community-based individuals with painful TMD demonstrated higher levels of pain catastrophising, and this catastrophising was associated with increased pain intensity and jaw dysfunction. The relatively low scores of pain catastrophising suggest that even mild catastrophic thinking is associated with pain perception and jaw function, and should be considered in patient management.

Negative effect of anger on chronic pain intensity is modified by multiple mood states other than anger: A large population-based cross-sectional study in Japan.

To investigate whether mood states other than anger can modify the association between anger and pain intensity in individuals with chronic pain. We analysed 22,059 participants with chronic pain, including 214 participants with rheumatoid arthritis (RA), who completed a questionnaire. The Profile of Mood States short form (POMS-SF) was used to assess six dimensions of mood states (anger-hostility, tension-anxiety, depression-dejection, confusion, fatigue, and vigour). A numerical rating scale (NRS) assessed pain intensity. We examined the association between anger-hostility and the NRS and the relationship between POMS-SF components. Moderation analyses were used to investigate whether the five mood states other than anger-hostility modified the effect of anger-hostility on the NRS. Anger-hostility contributed to pain intensity. Although increased mood states other than vigour were associated with increased pain intensity, these increased mood states appeared to suppress the effect of anger-hostility on pain intensity. Increased vigour was associated with decreased pain intensity and increased the effect of anger-hostility on pain intensity. Mood states other than anger may influence the association between anger and pain intensity in individuals with chronic pain. It is important to focus on complicated mood states and anger in individuals with chronic pain, including RA.

Strength training in addition to neuromuscular exercise and education in individuals with knee osteoarthritis-the effects on pain and sensitization.

There is a lack of evidence of the relative effects of different exercise modes on pain sensitization and pain intensity in individuals with knee osteoarthritis (KOA). Ninety individuals with radiographic and symptomatic KOA, ineligible for knee replacement surgery, were randomized to 12weeks of twice-weekly strength training in addition to neuromuscular exercise and education (ST+NEMEX-EDU) or neuromuscular exercise and education alone (NEMEX-EDU). Outcomes were bilateral, lower-leg, cuff pressure pain- and tolerance thresholds (PPT, PTT), temporal summation (TS), conditioned pain modulation (CPM), self-reported knee pain intensity and number of painful body sites. After 12weeks of exercise, we found significant differences in increases in PPT (-5.01kPa (-8.29 to -1.73, p=.0028)) and PTT (-8.02kPa (-12.22 to -3.82, p=.0002)) in the KOA leg in favour of ST+NEMEX-EDU. We found no difference in effects between groups on TS, CPM or number of painful body sites. In contrast, there were significantly greater pain-relieving effects on VAS mean knee pain during the last week (-8.4mm (-16.2 to -0.5, p=.0364) and during function (-16.0mm (-24.8 to -7.3, p=.0004)) in favour of NEMEX-EDU after 12weeks of exercise. Additional strength training reduced pain sensitization compared to neuromuscular exercise and education alone, but also attenuated the reduction in pain intensity compared to neuromuscular exercise and education alone. The study provides the first dose- and type-specific insight into the effects of a sustained exercise period on pain sensitization in KOA. Future studies are needed to elucidate the role of different exercise modes. This study is an important step towards better understanding the effects of exercise in pain management of chronic musculoskeletal conditions. We found that strength training in addition to neuromuscular exercise and education compared with neuromuscular exercise and education only had a differential impact on pain sensitization and pain intensity, but also that regardless of the exercise mode, the positive effects on pain sensitization and pain intensity were comparable to the effects of other therapeutic interventions for individuals with knee osteoarthritis.

An Examination of Day-to-Day and Intraindividual Pain Variability in Low Back Pain.

This study aimed to capture day-to-day changes in pain intensity in individuals with low back pain (LBP), which may be indicative of patients' ability to modulate their pain levels. A secondary aim was to explore the presence of latent subgroups characterized by pain level, intraindividual pain variability, and change in pain over a 14-day period. Participants were 54 adults with self-reported LBP recruited from outpatient physical therapy clinics and the community. Over the course of 14 days, participants completed daily measures of pain intensity, catastrophizing, pain self-efficacy, and negative affect. Change in pain intensity as well as total amount of intraindividual pain variability were also calculated. Daily increases in maladaptive coping and affective responses (i.e., higher catastrophizing, higher negative affect, lower pain self-efficacy) were associated with increases in pain intensity. A hierarchical cluster analysis revealed three subgroups: 1) moderate pain intensity, moderate pain variability, increase in pain over time; 2) low pain intensity, low pain variability, no change in pain over time; and 3) moderate pain intensity, high pain variability, decrease in pain over time. Cluster 2 demonstrated more adaptive coping and affective responses at baseline and during the 14-day period, and clusters 1 and 3 did not differ in their coping or affective responses. These findings provide support that day-to-day changes in pain, coping, and affective responses are meaningful and provide additional evidence of pain variability as a potential phenotypic characteristic.