The Effect of Virtual Reality on Cold Pain Sensitivity in Patients with Fibromyalgia and Pain-Free Individuals: A Randomized Crossover Study.

Introduction: Fibromyalgia is a complex pain syndrome with high personal and societal costs, with only few effective tools for treatment. Virtual reality (VR) may be an efficient pain management tool although the effectiveness in fibromyalgia patients is unclear. Objective: This randomized crossover study set out to 1) investigate the effect of VR on cold pain threshold, -tolerance, and -intensity in fibromyalgia patients and in pain-free individuals and 2) explore the potential relationships between the effect of VR and pain catastrophizing. Materials and Methods: Twenty-two female fibromyalgia patients and 22 sex- and age-matched pain-free individuals participated in two conditions (one with VR and one without VR) with foot immersion in 1°C-2°C cold water. The order of conditions was randomized and counterbalanced for each group. Conditions were separated by 20 minutes. Cold pain threshold, -tolerance, and -intensity were assessed during the conditions. Pain catastrophizing was assessed using the Pain Catastrophizing Scale. Results: VR induced moderate to large increases in cold pain threshold and pain tolerance compared with the control condition for both the fibromyalgia group and pain-free individuals (P < 0.03). Pain intensity was reduced after VR only in pain-free individuals (P < 0.003). Pain catastrophizing was not related to VR effect on pain threshold, -tolerance, or -intensity for any group. Conclusion: VR had a significant effect on pain threshold and tolerance in fibromyalgia patients and pain-free individuals, which supports its ability to distract from pain. Future studies exploring the VR's potential as part of clinical pain management alone or in combination with other treatments are warranted. ClinicalTrials.gov (NCT04294914).

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.

The impact of prolonged experimental neck pain on walking stability and gait kinematics - A parallel-group study.

BACKGROUND: Neck pain is a common problem in the general population, and movement adaptations are a natural response to pain. Previous studies have reported reduced trunk rotation during walking in those suffering from clinical neck pain. However, it is unknown how soon after the onset of pain, movement adaptations are adopted. This study investigated the effect of prolonged experimental neck pain four days after pain onset on gait kinematics during walking. METHODS: Forty healthy participants were randomized to receive injections of nerve-growth-factor or a control injection of isotonic saline into the right splenius capitis muscle at the end of days 0 and 2. Participants performed two walking tasks, walking and walking while reading on a smartphone, on days 0, 4, and 15. Gait kinematics, spatiotemporal parameters, and gait stability were measured using Xsens Awinda. FINDINGS: The nerve-growth-factor group reported increased neck pain intensity (median VAS 17.5 [IQR: 2.75-25.75]) on day 4 compared to day 0 and day 15. No pain intensity changes between days were reported for the isotonic-group. For gait kinematics, a main effect of the task was identified, showing that during the smartphone condition, participants had shorter stride lengths and reduced RoM for the trunk, hip, knee, and ankle compared to normal waking (P < 0.006). INTERPRETATION: Walking while reading on a smartphone, but not mild neck muscle pain, caused changes in the gait kinematics compared to normal walking without neck pain. This finding suggests that movement alterations during walking are not an early feature of prolonged experimental neck pain.

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.

Acute exercise of painful muscles does not reduce the hypoalgesic response in young healthy women - a randomized crossover study.

OBJECTIVES: Exercise-induced hypoalgesia (EIH) is characterized by an increase in pain threshold following acute exercise. EIH is reduced in some individuals with chronic musculoskeletal pain, although the mechanisms are unknown. It has been hypothesized that this may relate to whether exercises are performed in painful or non-painful body regions. The primary aim of this randomized experimental crossover study was to investigate whether the presence of pain per se in the exercising muscles reduced the local EIH response. The secondary aim was to investigate if EIH responses were also reduced in non-exercising remote muscles. METHODS: Pain-free women (n=34) participated in three separate sessions. In session 1, the maximal voluntary contraction (MVC) for a single legged isometric knee extension exercise was determined. In sessions 2 and 3, pressure pain thresholds (PPT) were assessed at the thigh and shoulder muscles before and after a 3-min exercise at 30 % of MVC. Exercises were performed with or without thigh muscle pain, which was induced by either a painful injection (hypertonic saline, 5.8 %) or a non-painful injection (isotonic saline, 0.9 %) into the thigh muscle. Muscle pain intensity was assessed with an 11-point numerical rating scale (NRS) at baseline, after injections, during and after exercises. RESULTS: PPTs increased at thigh and shoulder muscles after exercise with painful (14.0-24.9 %) and non-painful (14.3-19.5 %) injections and no significant between-injection EIH differences were observed (p>0.30). Muscle pain intensity was significantly higher following the painful injection compared to the non-painful injection (p<0.001). CONCLUSIONS: Exercising painful muscles did not reduce the local or remote hypoalgesic responses, suggesting that the pain-relieving effects of isometric exercises are not reduced by exercising painful body regions. ETHICAL COMMITTEE NUMBER: S-20210184. TRIAL REGISTRATION NUMBER: NCT05299268.

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.

Soft-collar use in rehabilitation of whiplash-associated disorders - A systematic review and meta-analysis.

BACKGROUND: Active rehabilitation of Whiplash Associated Disorders (WAD) is favoured over passive modalities such as soft-collars. However, the effectiveness of soft-collar use remains unclear. OBJECTIVE: To investigate the effectiveness of soft-collar use on pain and disability in WAD. DESIGN: Systematic review. METHOD: Databases (AMED, CINAHL Complete, Cochrane Library, Embase, Medline, PEDro, PsycINFO, PubMed, SPORTDiscus) were searched for guidelines, reviews and RCTs on soft-collar use as part of WAD treatment. Reference lists of reviews and guidelines were screened for additional RCTs. Study quality was rated using the PEDro-scale and overall quality of evidence with GRADE. RESULTS: Four RCTs (n = 409) of fair-good quality (PEDro-scores) were included with three using a soft collar in addition to other conservative treatment while one study compared soft-collar use to act-as-usual. All studies found that an active or act-as-usual approach was more effective in reducing pain intensity compared to soft-collar use, confirmed by meta-analysis (two RCTs with data: SMD of -0.80 (-1.20, -0.41)). No studies reported disability outcomes while contrasting results were found between groups regarding total cervical range of motion (two RCTs with data: SMD of 0.16 (-0.21, 0.54)) or rotation (two RCTs with data: SMD of 0.54 (-0.19, 1.27)). Overall quality of the evidence was low to very low. CONCLUSION: All four RCTs favoured an active approach/act-as-usual over soft-collar treatment. However, due to methodological concerns and low certainty of evidence, future studies investigating soft collar use in combination with an active rehabilitation strategy for acute/subacute WAD are needed.

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.

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.

Cross-cultural adaptation of the Danish version of the Big Five Inventory - a dual-panel approach.

Background and aims Assessing personality in research can be of importance, especially due to the potential relationship between different personality traits and the manifestation of symptoms in different clinical conditions. Therefore, it is important to have valid and reliable tools that allow for the assessment of personality traits. In this study, the aim was to translate and culturally adapt the Big Five Inventory (BFI) to the Danish language. Methods A dual panel approach, consisting of a 4-person bilingual panel and an 8-person panel with laymen, was used to translate and culturally adapt the questionnaire. A third 9-person panel consisting of people with different medical diagnosis was used to assess the face validity. Internal consistency (Cronbach's α) and test-retest reliability (intraclass correlation coefficients (ICC)) were tested amongst 96 subjects. Results The translated version demonstrated adequate internal consistency (0.66-0.84) and good-excellent test-retest reliability (0.86-0.95). The smallest detectable change is between 1.13-1.70 for the five subscales. Both the healthy and patient panels of laymen considered the questionnaire too long. Conclusion This translated version of the Big Five Inventory demonstrated high to very high test-retest reliability and, for most parts, an acceptable internal consistency. The construct validity was however different from versions translated into languages geographically and culturally similar to Danish. Implications Assessing the Big Five personality traits in Danish populations can be valuable for many reasons, e.g. when assessing people in pain in both clinical and experimental settings. Improved knowledge of the underlying driver of pain conditions is important. Here, understanding how personality may interact with pain can help researchers and clinicians.

Head repositioning accuracy is influenced by experimental neck pain in those most accurate but not when adding a cognitive task.

Background and aims Neck pain can impair perception of cervical movement, but how this is affected by attention is unknown. In this study, the effects of experimental neck pain on head repositioning accuracy during standardized head movements were investigated. Methods Experimental neck pain was induced by injecting hypertonic saline into the right splenius capitis muscle in 28 healthy participants (12 women). Isotonic saline was used as control. Participants were blindfolded while performing standardized head movements from neutral (start) to either right-rotation, left-rotation, flexion or extension, then back to neutral (end). Movements were triplicated for each direction, separated by 5-s, and performed with or without a cognitive task at baseline, immediately after the injection, and 5-min after pain disappeared. Repositioning accuracy was assessed by 3-dimensional recordings of head movement and defined as the difference between start and end position. Participants were grouped into most/least accurate based on a median split of head repositioning accuracy for each movement direction at baseline without the cognitive task. Results The most accurate group got less accurate following hypertonic injection during right-rotation without a cognitive task, compared with the least accurate group and the isotonic condition (p < 0.01). No group difference was found when testing head repositioning accuracy while the participants where distracted by the cognitive task. Conclusions Experimental neck pain alters head repositioning accuracy in healthy participants, but only in those who are most accurate at baseline. Interestingly, this impairment was no longer present when a cognitive task was added to the head repositioning accuracy test. Implications The results adds to our understanding of what factor may influence the head repositioning accuracy test when used in clinical practice and thereby how the results should be interpreted.