Regional and widespread pain sensitivity decreases following stretching in both men and women - Indications of stretch-induced hypoalgesia.

INTRODUCTION: This study aimed to investigate the effect of sex on regional and widespread pain sensitivity following acute bouts of stretching and to investigate the acute effect of stretching on regional and widespread pain sensitivity following stretching. METHODS: 73 healthy adults (36 females; mean age 25.6 ± 6.7 years) with an age range from 19 to 62 years were recruited for this experimental study. Regional and distant pain pressure pain thresholds, passive knee extension range of motion and passive resistive torque were measured before and 30 s after four bouts of 30-s static muscle stretching of the knee flexors with 20-s rest between bouts. RESULTS: No significant sex differences were found for pressure pain thresholds (p > 0.132), range of motion (p = 0.446) or passive resistive torque (p = 0.559) between pre-stretch and post-stretch measures. There were significant increases in pressure pain thresholds (p = 0.010), range of motion (p = 0.001) and passive resistive torque (p = 0.007) between pre-stretch and post-stretch measures. CONCLUSION: Muscle stretching significantly decreased regional and widespread pain sensitivity, indicating that central pain-modulating mechanisms are engaged during muscle stretching, resulting in stretch-induced hypoalgesia. Moreover, the results showed that the effect of stretching on regional and widespread pain sensitivity is not sex-specific.

Assessing standing balance with MOTI: a validation study.

OBJECTIVES: This study aimed to determine the validity and reliability of a new device called MOTI for measuring balance by comparing its performance that with of the gold-standard force platform. METHODS: The study involved collecting data from both devices in dual- and single-leg standing positions with eyes open and closed and using statistical measures to compare their performance. RESULTS: The results showed that MOTI can accurately measure balance during dual-leg standing tasks but has poor to moderate performance during single-leg standing tasks. However, it could detect small changes in postural sway caused by a reduced base of support and/or visual feedback. The study also found that the test-retest reliability was poor to moderate for both devices. CONCLUSIONS: These findings suggest that MOTI has potential as a reliable tool for measuring balance during certain tasks, but further research is needed to improve its performance during single-leg standing. This study provides valuable insights into the validity and reliability of MOTI for measuring balance and highlights the need for further investigation.

Sensory, functional and electromyographic variables show different recovery patterns over a seven day period following exercise-induced pain in the hamstrings.

BACKGROUND: Delayed-onset muscle soreness (DOMS) is common after unaccustomed exercises and can restrict performance if intense physical activities are performed while the muscle is still sore. This study aimed to evaluate the recovery process following exercise-induced DOMS over a seven-day period by evaluating sensory, functional, and electromyographic parameters. METHODS: Twenty-four healthy males participated in four experimental sessions (Day-0, Day-2, Day-4, Day-7). Pain perception, pressure pain sensitivity, active range of motion, maximal isometric strength, and muscle activity of the hamstrings during the maximal isometric contraction were assessed bilaterally at each session. A single-leg deadlift eccentric exercise (5-sets of 20-reps) was performed at the end of Day-0 to induce DOMS in the dominant leg. FINDINGS: At Day-2, the DOMS-side showed increased pain sensitivity and decreased active range of motion, strength and muscle activity compared to Day-0 (P < 0.015). Muscle activity on the DOMS-side reached similar values than at baseline on Day-4, whereas pain perception, pressure pain sensitivity, maximal isometric strength, and active range of motion had returned to the baseline state on Day-7. No changes over time were observed on the control-side, showing all variables an excellent reliability between values at Day-0 and Day-7 (Intraclass Correlation Coefficient > 0.90). INTERPRETATION: Surface electromyographic values during a maximal isometric contraction recover faster than the other parameters. Given the heterogeneous path of altered variables towards DOMS recovery, trainers and clinicians should consider a multimodal assessment, including quantitative sensory and functional measures in addition to the subjective perception of recovery.

Spanish version of the pain beliefs questionnaire: Translation, cross-cultural adaptation, validation, and psychometric properties in a working population.

BACKGROUND: Chronic musculoskeletal pain is a major health problem and a common cause of disability in the workplace. Beliefs related to musculoskeletal pain may influence its onset and perpetuation. Consequently, tools designed to identify potentially harmful beliefs are needed. However, the Pain Beliefs Questionnaire (PBQ) is not available for individuals speaking European-Spanish. OBJECTIVES: To translate and culturally adapt the original English version of the PBQ into European-Spanish and evaluate its psychometric properties among Spanish workers with and without chronic musculoskeletal pain. DESIGN: Study on measurement properties. METHODS: A translation and cultural adaptation process was based on a forward-backward translation process. One hundred fifty-one active workers were included. Participants completed the PBQ (composed of the organic and psychological subscales), the Pain Catastrophizing Scale (PCS), and the Hospital Anxiety and Depression Scale (HADS). Finally, thirty participants completed the PBQ again two weeks later for test-retest reliability. RESULTS: The PBQ showed adequate internal consistency (Cronbach's alpha: 0.72-0.73), good item response stability (weighted Kappa: 0.65-0.90), and reliability (Intraclass Correlation Coefficient: 0.72-0.80). A positive correlation was found between the PCS and the organic subscale (r = 0.403). However, no significant correlations were found between the HADS and the PBQ subscales. Workers with chronic musculoskeletal pain showed greater scores in the organic subscale and lower scores in the psychological subscale than workers without pain. CONCLUSION: The Spanish version of the PBQ was linguistically accurate and acceptable for use by workers with and without musculoskeletal pain.

Validity of an inertial measurement unit for the assessment of range and quality of movement during head and thoracic spine movements.

BACKGROUND: Patients with spinal pain often exhibit movement limitations and altered motor control, which can be challenging to measure accurately in clinical practice. Inertial measurement sensors present a promising new opportunity to develop valid, low-cost, and easy-to-use methods for assessing and monitoring spinal motion in a clinical setting. AIM: This study aimed to investigate the agreement of an inertial sensor and a 3D camera system for assessing the range of motion (ROM) and quality of movement (QOM) in head and trunk single-plane movements. METHODS: Thirty-three healthy, pain-free volunteers were included. Each participant performed movements of the head (cervical flexion, extension, and lateral flexion) and trunk (trunk flexion, extension, rotation, and lateral flexion), which were simultaneously recorded by a 3D camera system and an inertial measurement unit (MOTI, Aalborg, Denmark). Agreement and consistency were analyzed for ROM and QOM by determining intraclass correlation coefficients (ICC), mean bias, and with Bland-Altman plots. RESULTS: The agreement between systems was excellent for all movements (ICC between 0.91 and 1.00) for ROM and good to excellent for the QOM (ICC between 0.84 and 0.95). The mean bias for all movements (0.1-0.8°) was below the minimum acceptable difference between devices. The Bland-Altman plot indicated that MOTI systematically measured a slightly greater ROM and QOM than the 3D camera system for all neck and trunk movements. CONCLUSION: This study showed that MOTI is a feasible and potentially applicable option to assess ROM and QOM for head and trunk movements in experimental and clinical settings.

Cross-cultural translation and adaptation of the Danish version of the brief version of the 10-item Big Five Inventory.

BACKGROUND: Personality traits are associated with pain-related beliefs and coping strategies, and different chronic conditions are linked through specific personality profiles. This highlights the importance of having valid and reliable measures of personality traits for use in clinical and research settings when assessing patients in chronic pain. PURPOSE: To translate and cross-culturally adapt the 10-item Big Five Inventory (BFI-10) into Danish. METHODS: A bilingual expert panel (N = 4) and a panel of laymen (N = 8) translated and culturally adapted the questionnaire into Danish. Face validity was evaluated in a group of persons suffering from recurring or ongoing painful conditions (N = 9). Data were collected to evaluate the internal consistency, test-retest reliability and factor structure (N = 96). RESULTS: Some of the participants in the lay panel considered the questionnaire too short, considering its aim of assessing personality. Acceptable internal consistency was found for two out of five subscales (0.78 for both Extraversion and Neuroticism), while the internal consistency was non-acceptable for the remaining subscales (0.17-0.45). Test-retest reliability was acceptable for three subscales (0.80 for Neuroticism, 0.84 for Conscientiousness, and 0.85 for Extraversion). Assumptions for determining the factor structure were not met and therefore was this analysis omitted. DISCUSSION: Although face valid, only two out of five subscales had acceptable internal consistency and only three subscales had acceptable test-retest reliability. These findings indicate that interpreting findings regarding personality using the Danish BFI-10 should be done with caution.

Long-term consistency of clinical sensory testing measures for pain assessment.

Background: Understanding the stability of quantitative sensory tests (QSTs) over time is important to aid clinicians in selecting a battery of tests for assessing and monitoring patients. This study evaluated the short- and long-term reliability of selected QSTs. Methods: Twenty healthy women participated in three experimental sessions: Baseline, 2 weeks, and 6 months. Measurements included pressure pain thresholds (PPT) in the neck, upper back, and leg; Pressure-cuff pain tolerance around the upper-arm; conditioned pain modulation during a pressure-cuff stimulus; and referred pain following a suprathreshold pressure stimulation. Intraclass correlation coefficients (ICC) and minimum detectable change (MDC) were calculated. Results: Reliability for PPT was excellent for all sites at 2 weeks (ICC, 0.96-0.99; MDC, 22-55 kPa) and from good to excellent at 6 months (ICC, 0.88-0.95; MDC, 47-91 kPa). ICC for pressure-cuff pain tolerance indicated excellent reliability at both times (0.91-0.97). For conditioned pain modulation, reliability was moderate for all sites at 2 weeks (ICC, 0.57-0.74; MDC, 24%-35%), while it was moderate at the neck (ICC, 0.54; MDC, 27%) and poor at the upper back and leg at 6 months. ICC for referred pain areas was excellent at 2 weeks (0.90) and good at 6 months (0.86). Conclusions: PPT, pressure pain tolerance, and pressure-induced referred pain should be considered reliable procedures to assess the pain-sensory profile over time. In contrast, conditioned pain modulation was shown to be unstable. Future studies prospectively analyzing the pain-sensory profile will be able to better calculate appropriate sample sizes.

Prolonged slumped sitting causes neck pain and increased axioscapular muscle activity during a computer task in healthy participants - A randomized crossover study.

INTRODUCTION: Sitting posture may contribute to spinal pain. Effects of postures on pain, sensitivity and muscle activity during computer tasks were investigated. METHODS: Twenty-five healthy participants, seated at a workstation without backrest, completed four, 15-min typing tasks: A)Upright with forearm-support; B)Upright without forearm-support; C)Slumped with forearm-support; D)Slumped without forearm-support. Participants rated pain every minute on a numerical rating scale (NRS). RMS-EMG was recorded from upper/lower trapezius (UT, LT), serratus anterior and anterior/middle deltoid. At baseline and after tasks, pressure pain thresholds (PPTs) were recorded bilaterally over the head, UT, and leg. RESULTS: All tasks caused clinically relevant increased NRS (≥2/10) compared to baseline (P < 0.001). NRS was higher in Task-D (P < 0.003) and lower in Task-B (P < 0.005) than others. PPTs did not change from baseline. Task-D caused higher UT and LT RMS-EMG (P < 0.02) than other tasks. CONCLUSION: A 15-min task caused pain irrespective of posture with some causing larger changes than others.

What is known and what is still unknown within chronic musculoskeletal pain? A systematic evidence and gap map.

ABSTRACT: Evidence and gap maps (EGMs) can be used to identify gaps within specific research areas and help guide future research agendas and directions. Currently, there are no EGMs within the broad domain of chronic musculoskeletal (MSK) pain in adults. The aim of this study was to create a contemporary EGM of interventions and outcomes used for research investigating chronic MSK pain. This EGM was based on systematic reviews of interventions published in scientific journals within the past 20 years. Embase, PubMed, the Cochrane Library, and PsycINFO were used to retrieve studies for inclusion. The quality of the included reviews was assessed using AMSTAR-II. Interventions were categorised as either physical, psychological, pharmacological, education/advice, interdisciplinary, or others. Outcomes were categorised using the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) recommendations. Of 4299 systematic reviews, 457 were included. Of these, 50% were rated critically low quality, 25% low quality, 10% moderate quality, and 15% rated high quality. Physical interventions (eg, exercise therapy) and education were the most common interventions reported in 80% and 20% of the studies, respectively. Pain (97%) and physical functioning (87%) were the most reported outcomes in the systematic reviews. Few systematic reviews used interdisciplinary interventions (3%) and economic-related outcomes (2%). This contemporary EGM revealed a low proportion of high-quality evidence within chronic MSK pain. This EGM clearly outlines the lack of high-quality research and the need for increased focus on interventions encompassing the entire biopsychosocial perspective.

Participatory research: a Priority Setting Partnership for chronic musculoskeletal pain in Denmark.

OBJECTIVES: Patient and stakeholder engagements in research have increasingly gained attention in healthcare and healthcare-related research. A common and rigorous approach to establish research priorities based on input from people and stakeholders is the James Lind Alliance Priority Setting Partnership (JLA-PSP). The aim of this study was to establish research priorities for chronic musculoskeletal (MSK) pain by engaging with people living with chronic MSK pain, relatives to people living with chronic MSK pain, healthcare professionals (HCP), and researchers working with chronic MSK pain. METHODS: This JLA-PSP included a nation-wide survey in Denmark, an interim prioritisation, and an online consensus building workshop. The information gained from this was the basis for developing the final list of specific research priorities within chronic MSK pain. RESULTS: In the initial survey, 1010 respondents (91% people living with chronic MSK pain/relatives, 9% HCPs/researchers) submitted 3121 potential questions. These were summarised into 19 main themes and 36 sub-themes. In the interim prioritisation exercise, 51% people living with pain/relatives and 49% HCPs/researchers reduced the list to 33 research questions prior to the final priority setting workshop. 23 participants attended the online workshop (12 people/relatives, 10 HCPs, and 1 researcher) who reached consensus for the most important research priorities after two rounds of discussion of each question. CONCLUSIONS: This study identified several specific research questions generated by people living with chronic MSK pain, relatives, HCPs, and researchers. The stakeholders proposed prioritization of the healthcare system's ability to support patients, focus on developing coherent pathways between sectors and education for both patients and HCP. These research questions can form the basis for future studies, funders, and be used to align research with end-users' priorities.

Not just sensitization: sympathetic mechanisms contribute to expand experimental referred pain.

Background: Widespread pain partially depends upon sensitization of central pain mechanisms. However, mechanisms controlling pain distribution are not completely known. The present study sought to assess skin temperature variations in the area of experimentally-induced pain and potential sex differences. Methods: Pressure-pain thresholds (PPTs) were measured on the right infraspinatus muscle. At the end of Day 0, all participants performed an eccentric exercise of the shoulder external rotators to induce muscle soreness 24 hours after. On Day 1, participants indicated on a body chart the area of pain induced by 60 seconds of suprathreshold pressure stimulation (STPS; PPT + 20%) on the right infraspinatus muscle. Skin temperature variations in the area of referred pain were recorded with an infrared thermography camera, immediately before and after the STPS. Results: Twenty healthy, pain-free individuals (10 females) participated. On Day 0, the pre-STPS temperature was higher than the post-STPS temperature on the arm (P = 0.001) and forearm (P = 0.003). On Day 1, the pre-STPS temperature was higher than the post-STPS temperature on the shoulder (P = 0.015), arm (P = 0.001), and forearm (P = 0.010). On Day 0, the temperature decrease after STPS in females was greater than in males on the forearm (P = 0.039). On Day 1, a greater temperature decrease was found amongst females compared with males at the shoulder (P = 0.018), arm (P = 0.046), and forearm (P = 0.005). Conclusions: These findings indicate that sympathetic vasomotor responses contribute to expand pressure-induced referred pain, especially among females.

Spatiotemporal patterns of pain distribution and recall accuracy: a dose-response study.

OBJECTIVES: Clinical decisions rely on a patient's ability to recall and report their pain experience. Monitoring pain in real-time (momentary pain) may reduce recall errors and optimize the clinical decision-making process. Tracking momentary pain can provide insights into detailed changes in pain intensity and distribution (area and location) over time. The primary aims of this study were (i) to measure the temporal changes of pain intensity, area, and location in a dose-response fashion and (ii) to assess recall accuracy of the peak pain intensity and distribution seven days later, using a digital pain mapping application. The secondary aims were to (i) evaluate the influence of repeated momentary pain drawings on pain recall accuracy and (ii) explore the associations among momentary and recall pain with psychological variables (pain catastrophizing and perceived stress). METHODS: Healthy participants (N=57) received a low (0.5 ml) or a high (1.0 ml) dose of hypertonic saline (5.8%) injection into the right gluteus medius muscle and, subsequently, were randomized into a non-drawing or a drawing group. The non-drawing groups reported momentary pain intensity every 30-s. Whereas the drawing groups reported momentary pain intensity and distribution on a digital body chart every 30-s. The pain intensity, area (pixels), and distribution metrics (compound area, location, radiating extent) were compared at peak pain and over time to explore dose-response differences and spatiotemporal patterns. All participants recalled the peak pain intensity and the peak (most extensive) distribution seven days later. The peak pain intensity and area recall error was calculated. Pain distribution similarity was determined using a Jaccard index which compares pain drawings representing peak distribution at baseline and recall. The relationships were explored among peak intensity and area at baseline and recall, catastrophizing, and perceived stress. RESULTS: The pain intensity, area, distribution metrics, and the duration of pain were lower for the 0.5 mL than the 1.0 mL dose over time (p<0.05). However, the pain intensity and area were similar between doses at peak pain (p>0.05). The pain area and distribution between momentary and recall pain drawings were similar (p>0.05), as reflected in the Jaccard index. Additionally, peak pain intensity did not correlate with the peak pain area. Further, peak pain intensity, but not area, was correlated with catastrophizing (p<0.01). CONCLUSIONS: This study showed differences in spatiotemporal patterns of pain intensity and distribution in a dose-response fashion to experimental acute low back pain. Unlike pain intensity, pain distribution and area may be less susceptible in an experimental setting. Higher intensities of momentary pain do not appear to influence the ability to recall the pain intensity or distribution in healthy participants. IMPLICATIONS: The recall of pain distribution in experimental settings does not appear to be influenced by the intensity despite differences in the pain experience. Pain distribution may add additional value to mechanism-based studies as the distribution reports do not vary with pain catastrophizing. REC# N-20150052.

Reducing the Weight of Spinal Pain in Children and Adolescents.

Spinal pain in adults is a significant burden, from an individual and societal perspective. According to epidemiologic data, spinal pain is commonly found in children and adolescents, where evidence emerging over the past decade has demonstrated that spinal pain in adults can, in many cases, be traced back to childhood or adolescence. Nevertheless, very little focus has been on how to best manage spinal pain in younger age groups. The purpose of this article is to put the focus on spinal pain in children and adolescents and highlight how and where these problems emerge and how they are commonly dealt with. We will draw on findings from the relevant literature from adults to highlight potential common pathways that can be used in the management of spinal pain in children and adolescents. The overall focus is on how healthcare professionals can best support children and adolescents and their caregivers in making sense of spinal pain (when present) and support them in the self-management of the condition.

Development of the Prevent for Work Questionnaire (P4Wq) for the assessment of musculoskeletal risk factors in the workplace: part 2-pilot study for questionnaire development and validation.

OBJECTIVE: The aim of this study was to develop a multifactorial, self-report questionnaire: Prevent for Work Questionnaire (P4Wq). The questionnaire is intended for screening for risk factors in work-related musculoskeletal disorders (WMSDs). DESIGN: Data were collected from otherwise healthy workers employed in three service areas at a specialist hospital in Italy: healthcare, administration and ancillary services. SETTING AND PARTICIPANTS: In all, 115 participants were enrolled (67% women; average age 41.5±9.94 years). The content of the tool for WMSDs was derived from three participation rounds of analysis involving a select group of experts who identified the questionnaire domains and items. Participants responded to 89 items in addition to the EuroQol 5 Dimensions Questionnaire (EQ-5D-5L), Fear-Avoidance Beliefs Questionnaire (FABq) and Oswestry Disability Index (ODI). The proportion of missing data and the distribution of responses were analysed for each item. Items with a discrimination index >0.40 and an interitem correlation <0.80 were retained. Factor analysis was performed using the VARIMAX rotation method, factor extraction, and identification, assignment of items to subscales, and assignment of scores to items. Internal consistency, reliability, construct validity and face validity were also assessed. RESULTS: A total of 52 items were included in the factor analysis and four subscales identified: Physical Stress Subscore (six items); Mental Stress Subscore (six items); Job Satisfaction Subscore (four items) and Kinesiophobia/Catastrophizing Subscore (four items). The items in the final questionnaire version had a factor loading >0.7. The questionnaire consisted of 20 items with good internal consistency (Cronbach's alpha 0.81-0.91), reliability (weighted kappa coefficient 0.617-1.00), good construct validity (EQ-5D-5L, r=-0.549, p<0.001; ODI, r=0.549, p<0.001; FABq work, r=0.688, p<0.001) and satisfactory face validity (universal validity index 96.04%). CONCLUSION: The P4Wq is a 20-item, multifactorial self-report risk assessment questionnaire. It may provide a useful tool for screening for WMSDs by specifically addressing back disorders. It investigates risks for individual workers and may inform educational programmes and preventive strategies tailored to a worker's needs. TRIAL REGISTRATION NUMBER: NCT04192604.

European knowledge alliance for innovative measures in prevention of work-related musculoskeletal pain disorders (Prevent4Work Project): protocol for an international mixed-methods longitudinal study.

INTRODUCTION: Work-related musculoskeletal (MSK) pain is a highly prevalent condition and one of the main contributors to disability and loss of work capacity. Current approaches to the management and prevention of work-related MSK pain do not consistently integrate current evidence-based knowledge and seem to be outdated. The Prevent4Work (P4W) Project aims to collect and spread evidence-based information to improve the management and prevention of work-related MSK pain. P4W will longitudinally investigate (1) risk factors associated with the prevalence of work-related MSK pain, (2) predictive factors for new events of work-related MSK pain in the short term and (3) the modification of pain beliefs after participating in evidence-based e-learning courses. METHODS AND ANALYSIS: This project employs a mixed-methods design with international cohorts of workers from Spain, Italy and Denmark. All participants will be assessed using self-reported variables at baseline (ie, cross-sectional design) with follow-up after 3 and 6 months (ie, prospective-predictive design). Throughout the first phase (0-3 months), all participants will be offered to self-enrol in e-learning courses on work-related MSK pain. Changes in pain beliefs (if any) will be assessed. The dataset will include sociodemographic characteristics, physical and psychological job demands, lifestyle-related factors, MSK pain history and pain beliefs. At baseline, all participants will additionally complete the P4W questionnaire developed to detect populations at high risk of suffering work-related MSK pain.Descriptive statistics, binary logistic regression, and analysis of variance will be used to identify the significant factors that influence the history of work-related MSK pain, evaluate the short-term prediction capacity of the P4W questionnaire, and investigate whether workers' participation in e-learning courses will modify their pain beliefs. ETHICS AND DISSEMINATION: The study received ethical approval from the Ethical Committee of San Jorge University (USJ011-19/20). The results will be made available via peer-reviewed publications, international conferences and P4W official channels.

The tolerance to stretch is linked with endogenous modulation of pain.

OBJECTIVES: The effect of stretching on joint range of motion is well documented, and although sensory perception has significance for changes in the tolerance to stretch following stretching the underlining mechanisms responsible for these changes is insufficiently understood. The aim of this study was to examine the influence of endogenous pain inhibitory mechanisms on stretch tolerance and to investigate the relationship between range of motion and changes in pain sensitivity. METHODS: Nineteen healthy males participated in this randomized, repeated-measures crossover study, conducted on 2 separate days. Knee extension range of motion, passive resistive torque, and pressure pain thresholds were recorded before, after, and 10 min after each of four experimental conditions; (i) Exercise-induced hypoalgesia, (ii) two bouts of static stretching, (iii) resting, and (iv) a remote, painful stimulus induced by the cold pressor test. RESULTS: Exercise-induced hypoalgesia and cold pressor test caused an increase in range of motion (p<0.034) and pressure pain thresholds (p<0.027). Moderate correlations in pressure pain thresholds were found between exercise-induced hypoalgesia and static stretch (Rho>0.507, p=0.01) and exercise-induced hypoalgesia and the cold pressor test (Rho=0.562, p=0.01). A weak correlation in pressure pain thresholds and changes in range of motion were found following the cold pressor test (Rho=0.460, p=0.047). However, a potential carryover hypoalgesic effect may have affected the results of the static stretch. CONCLUSIONS: These results suggest that stretch tolerance may be linked with endogenous modulation of pain. Present results suggest, that stretch tolerance may merely be a marker for pain sensitivity which may have clinical significance given that stretching is often prescribed in the rehabilitation of different musculoskeletal pain conditions where reduced endogenous pain inhibition is frequently seen.

Changes in Pain Sensitivity and Conditioned Pain Modulation During Recovery From Whiplash-associated Disorders.

OBJECTIVE: The objective of this study was to investigate the pain-sensory profile of patients with whiplash-associated disorders (WADs) prior and post 2 weeks of standardized rehabilitation and after a 6-month follow-up. MATERIALS AND METHODS: Twenty-two WAD participants (grade II; 14 women) and 22 sex-matched and age-matched healthy pain-free controls were enrolled. Pressure pain thresholds (PPTs) were assessed at local and distal muscles. Conditioned pain modulation (CPM) of PPTs was assessed using cuff pressure around the upper arm. Referred area of pain following supra-threshold pressure stimulation of the infraspinatus muscle was recorded on a body chart. Psychometric variables (pain intensity, area of perceived pain, pain catastrophizing, kinesiophobia, sleep problems, and depression level) were assessed. WAD group additionally completed the Neck Disability Index. RESULTS: The WAD group demonstrated lower local PPTs compared with controls at all time points (P<0.05) and lower distal PPTs at baseline and at 2 weeks when compared with 6 months (within-group) (P<0.05). The WAD group had a reduced CPM response and larger induced referred pain areas compared with controls (P<0.05), while no within-group changes were observed at any time point. The WAD group reported higher pain intensity and perceived area of pain compared with controls at all time points (P<0.05) and a mean Neck Disability Index score of 41% at baseline, 16% at 2 weeks, and 4% at 6 months. Furthermore, the WAD group reported improvements in all other psychometric variables (P<0.05), although only pain catastrophizing levels were comparable to controls at 2 weeks. DISCUSSION: PPTs but not CPM improved in the WAD group and were comparable to controls following 2 weeks following standardized rehabilitation, indicating that normalization of CPM may not be required to recover from WAD.

Pain referral area is reduced by remote pain.

BACKGROUND: Endogenous pain inhibitory mechanisms are known to reduce pain intensity, but whether they influence the size and distribution of pain referral is unclear. This study aimed to determine if referred pain is reduced by applying a remote, conditioning painful stimulus. METHODS: Twenty-four healthy men participated in this randomized, crossover study with a control and conditioning session. Referred pain was induced from the infraspinatus muscle (dominant side) by a painful pressure for 60 s. When applying pressure, the intensity was adjusted to a local pain intensity of 7/10 on a numerical rating scale. In the conditioning session, tonic painful pressure was simultaneously applied to the non-dominant leg during induction of referred pain. The area of referred pain was drawn onto a digital body chart and size extracted for data analysis. RESULTS: For the total group and in a subgroup with distinct patterns of referred pain (n = 15/24), the pain area perceived in the back and front+back was smaller during the conditioning compared with the control (p < 0.05). No significant difference was found between sessions in a subgroup only demonstrating local pain (n = 9/24). CONCLUSIONS: Engaging the descending noxious inhibitory control reduced the size of pain areas predominately when distinct pain referral was present. Assuming a conditioning effect of descending inhibitory control acting on dorsal horn neurons, these findings may indicate that mechanisms underlying pain referral can be modulated by endogenous control. The findings may indicate that referred pain may be a useful proxy to evaluate sensitivity of central pain mechanisms as previously suggested. SIGNIFICANCE: The current results indicate a link between endogenous inhibition and pain referral. Descending inhibitory control effects on pain referral support a spinal mechanism involved in pain referral. Future studies should investigate whether the spatial characteristics of referred pain (e.g. size, frequency of affected body regions and distribution away from the primary nociceptive stimulus) can useful to evaluate the efficiency of endogenous pain modulation.

Pain and Disability in Low Back Pain Can be Reduced Despite No Significant Improvements in Mechanistic Pain Biomarkers.

OBJECTIVE: Altered balance in nociception in response to noxious stimuli is commonly reported in chronic low back pain (LBP). However, it is unclear whether an improvement in the clinical presentation is contingent on a reduction in pain sensitivity. This study investigated whether the quantitative sensory testing (QST) profile changes in people undergoing rehabilitation for LBP. DESIGN: A prospective, observational case-control study. METHODS: Forty males and females, 18 to 40 years' old (20 with LBP) participated in 2 sessions. QST was performed at baseline and after discharge from rehabilitation (LBP) or after 3 to 8 weeks (controls). The QST battery consisted of determining pressure-pain thresholds at the low back and shoulder, temporal summation of pain, and conditioned pain modulation. Questionnaire data was used to determine pain (Numeric Rating Scale [NRS]), disability (Roland-Morris Questionnaire [RMQ]), Fear Avoidance Beliefs (FABQ), and The Örebro Musculoskeletal Pain Screening Questionnaire (ÖMPSQ) at baseline and discharge. The treatment effect was determined by calculating the Cohen d. RESULTS: No significant group×time interactions or main factor effect was found for any of the QST measures. The LBP group reported a significant reduction in NRS (P<0.0002, d=1.23), RMQ (P<0.0001, d=1.58), FABQ (P<0.001, d=0.87), and in the ÖMPSQ (P<0.00001, d=1.44). CONCLUSIONS: The results indicate that an improvement of clinical LBP is not contingent upon changes in the pain sensory profile. The value of screening pain sensitivity in LBP patients in primary care, needs to be investigated further, due to the patient population heterogeneity and the sensitivity of assessment methods.

Development of the Prevent for Work questionnaire (P4Wq) for assessment of musculoskeletal risk in the workplace: part 1-literature review and domains selection.

OBJECTIVE: This study aims to define appropriate domains and items for the development of a self-administered questionnaire to assess the risk of developing work-related musculoskeletal disorder (WMSD) and the risk of its progression to chronicity. DESIGN: Literature review and survey study. SETTING AND PARTICIPANTS: A literature review and a two-round interview with 15 experts in musculoskeletal pain were performed to identify the available domains for WMSD assessment. INTERVENTIONS AND OUTCOME: To ensure quality, only validated questionnaires were included for the Delphi process. A three-round Delphi method, with three round steps, was used to select the most pertinent and relevant domains and items. RESULTS: Nine questionnaires were identified through the expert discussion and literature review, comprising 38 candidate domains and 504 items. In the first round of the Delphi group, 17 domains reached more than 70% agreement and were selected. In the second round, 10 domains were rejected, while 11 were selected to complete the pool of domains. In the third and final round, 89 items belonging to 28 domains were defined as significant to develop a WMSDs risk assessment questionnaire. CONCLUSIONS: No specific risk assessment questionnaires for WMSDs were identified from the literature. WMSD risk of presence and chronicity can be defined by an assessment tool based on the biopsychosocial model and the fear-avoidance components of chronic pain. The present study provides the formulation and operationalisation of the constructs in domains and items needed for developing and validating the questionnaire.