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  • 51.
    Ekman, Bertil
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Internal Medicine. Östergötlands Läns Landsting, MC - Medicincentrum, EMT-endo.
    Gerdle, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Arnqvist, Hans
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Cell biology. Östergötlands Läns Landsting, MC - Medicincentrum, EMT-endo.
    Growth hormone substitution titrated to obtain IGF-I levels in the physiological range in hypopituitary adults: Effects upon dynamic strength, endurance and EMG2003In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 90, no 5-6, p. 496-504Article in journal (Refereed)
    Abstract [en]

    We studied the effects of individualised growth hormone (GH) substitution, aiming at normal insulin-like growth factor I (IGF-I) levels, on biomechanical output and surface electromyogram (EMG) of isokinetic muscle strength and endurance performance in 18 hypopituitary adults and compared with 17 matched healthy controls. The muscle function tests consisted of isokinetic contractions of the right knee extensors, from which torque and EMG were recorded. Three patients were excluded from the final analysis of the muscle function tests due to technical errors and one control subject moved from the area during the study. We found that GH-deficient adults without GH substitution were weaker and had less endurance than healthy control subjects. At the group level, plasma levels of IGF-I were normalised but generally no significant effects upon biomechanical output and EMG were found after dose titration and 6 months of a constant GH dose. However, subjects with the largest changes in IGF-I had significantly better biomechanical output and EMG compared to those with small changes in IGF-I. This finding may indicate that the net increase in IGF-I levels is critical for improvements in biomechanical output, EMG and perception of fatigue to occur.

  • 52.
    Ekman, Bertil
    et al.
    Linköping University, Department of Medicine and Care, Internal Medicine. Linköping University, Faculty of Health Sciences.
    Gerdle, Björn
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Arnqvist, Hans J.
    Linköping University, Department of Medicine and Care, Internal Medicine. Linköping University, Department of Biomedicine and Surgery, Cell biology. Linköping University, Faculty of Health Sciences.
    Improved muscle function in GH substituted adults is related to increase in circulating IGF-IManuscript (preprint) (Other academic)
    Abstract [en]

    We studied the effects of individualized growth hormone substitution, aiming at normal IGF-I levels, on biomechanical output and EMG of isokinetic muscle strength and endurance performance in 18 hypopituitary adults compared with matched controls. The muscle function tests consisted of isokinetic contractions of the dght knee extensors, and torque and EMG were recorded. Plasma levels of IGF-I were normalized, and peak torque at 90° s-1, and peak torque endurance level increased after dose titration and 6 months constant GH-dose. The change in IGF-I correlated positively with the changes in biomechanical output and EMG variables and a negative correlation existed with the perception of fatigue. Despite improvement during GH-substitution the patients still had about 10-20 % less muscle strength and endurance compared with the controls at the study end. In summary we found that individualized GH substitution improves muscle function and that the net increase in IGF-I levels indicates generally increases in biomechanical output and EMG variables and a lower perception of fatigue.

  • 53.
    Elert, Jessica
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine.
    Aspegren Kendall, Sally
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Larsson, Barbro
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine.
    Månsson, Bjarne
    Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Gerdle, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Chronic pain and difficulty in relaxing postural muscles in patients with fibromyalgia and chronic whiplash associated disorders2001In: Journal of Rheumatology, ISSN 0315-162X, E-ISSN 1499-2752, Vol. 28, no 6, p. 1361-1368Article in journal (Refereed)
    Abstract [en]

    Objective. To investigate if muscle tension according to the surface electromyogram (EMG) of the shoulder flexors is increased in consecutive patients with fibromyalgia (FM) or chronic whiplash associated disorders (WAD). Methods. A total of 59 consecutive patients with FM (n = 36) or chronic WAD (n = 23) performed 100 maximal isokinetic contractions combined with surface electromyography of the trapezius and infraspinatus. A randomized group of pain-free female (n = 27) subjects served as control group. Peak torque initially (Pti) and absolute and relative peak torque at endurance level (PTe, PTer) were registered as output variables, together with the EMG level of unnecessary muscle tension, i.e., the signal amplitude ratio (SAR). Results. The patient groups had a higher level of unnecessary tension initially and at the endurance level. The patients had lower absolute output (PTi and PTe), but the relative levels (PTer) did not differ comparing all 3 groups. Subjects with FM had significantly higher body mass index (BMI) than the other groups. BMI did not influence the SAR but correlated positively with PTi. Conclusion. The results confirmed earlier findings that groups of patients with chronic pain have increased muscle tension and decreased output during dynamic activity compared to pain-free controls. However, the results indicated there is heterogeneity within groups of patients with the same chronic pain disorder and that not all patients with chronic pain have increased muscle tension.

  • 54.
    Elert, Jessica
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Department of Health and Society, Division of Physiotherapy.
    Sterner, Ylva
    Nyberg, Vanja
    Gerdle, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Lack of gender differences in the ability to relax between repetitive maximum isokinetic shoulder forward flexions: A population-based study among northern Swedes2000In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 83, no 4-5, p. 246-256Article in journal (Refereed)
    Abstract [en]

    The aim of the present study was to analyse the effects of gender and age in a population-based sample of clinically healthy subjects on: (1) strength, endurance and perception of fatigue, (2) mean frequency (MNF) of the electromyogram (EMG), and (3) the ability to relax between active contractions (signal amplitude ratio, SAR) of the surface EMG of an isokinetic shoulder forward flexion test. With this aim we have analysed aspects of the validity of MNF as an indicator of fatigue, using peak torque as a criterion variable. The subjects were 27 men and 28 women (age range: 20-60 years), who were obtained by random sample from the official census lists (participation rate: 66%). The peak torque and surface EMG of two portions of the trapezius, deltoid and infraspinatus muscles were recorded throughout 100 repetitive maximal isokinetic shoulder forward flexions. No significant differences in the perception of fatigue and relative endurance levels of peak torque and work were found between males and females. Males were significantly stronger than females and, on average, females produced approximately 60% of the output of the males, 76% after normalisation for body mass. The men had significantly lower MNF endurance levels for three of the investigated muscles. When controlled for age and body mass, the men had a significantly higher MNF of the deltoid muscle than did the females. These differences were only found for the deltoid muscle. Significant correlations existed between the MNF of the four muscles and biomechanical output, indicating criterion validity for the MNF variable with respect to fatigue. There were no significant effects of gender or age on the ability to relax between repetitive contractions (SAR). The higher prevalence of musculoskeletal complaints of the neck-shoulder region in females cannot be explained by a higher intrinsic muscle tension. Age, gender, body mass index and biomechanical output can have significant effects upon MNF. These effects are important considerations in the interpretation of MNF, for instance in ergonomic situations.

  • 55.
    Elert, Jessica
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Sydnerth, S-B.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine/Pain Clinic. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Åbjörnsson, L.
    Gerdle, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Aspects of criterion validity and sensitivity of the BAS-health scale in chronic pain patients - a pilot study of patients at a multidisciplinary pain centre.1999In: Advances in Physics, ISSN 0001-8732, E-ISSN 1460-6976, Vol. 1, p. 83-97Article in journal (Refereed)
  • 56.
    Enthoven, Paul
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Physiotherapy. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in West Östergötland, Research & Development Unit in Local Health Care.
    Molander, Peter
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Öberg, Birgitta
    Linköping University, Department of Medical and Health Sciences, Division of Physiotherapy. Linköping University, Faculty of Medicine and Health Sciences.
    Stålnacke, Britt-Marie
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Department of Clinical Sciences, Karolinska Institutet and Department of Rehabilitation Medicine, Danderyd Hospital, Stockholm, Sweden.
    Stenberg, Gunilla
    Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, Umeå, Sweden.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Do pain characteristics guide selection for multimodal pain rehabilitation?2017In: Journal of Rehabilitation Medicine, ISSN 1650-1977, E-ISSN 1651-2081, Vol. 49, p. 161-169Article in journal (Refereed)
    Abstract [en]

    Objective: To determine whether self-reported painmeasures are associated with selection for multimodalor multidisciplinary rehabilitation (MMR) andwhether this selection is influenced by sex.Design: Cross-sectional cohort study.Subjects: A total of 1,226 women and 464 men withchronic pain conditions from 2 university hospitals.Methods: Drawing from the Swedish Quality Registryfor Pain Rehabilitation (SQRP), data on pain, psychologicalsymptoms, function, health, and activity/participation were collected. Multiple logistic regressionwas used to investigate association of painmeasures with selection for MMR (no/yes) aftermultidisciplinary assessment. Covariates were: age,educational level, anxiety, depression, working status,and several pain measures.Results: High pain intensity in the previous week(odds ratio (OR) 0.92; 95% confidence interval (CI)0.86–0.99) and high pain severity (MultidimensionalPain Inventory) (OR 0.83; 95% CI 0.74–0.95)were negatively associated with selection for MMR,whereas higher number of pain quadrants was positivelyassociated with selection for MMR. Similarresults were obtained for women, but none of themeasures was predictive for men.Conclusion: This practice-based study showed thathigher scores on self-reported pain were not associatedwith selection for MMR, and in women therewas a negative association for higher pain intensityand pain severity. Thus, other factors than pain determinewhether patients are selected for MMR.

  • 57.
    Ericsson, Anna
    et al.
    University of Gothenburg, Sweden.
    Palstam, Annie
    University of Gothenburg, Sweden.
    Larsson, Anette
    University of Gothenburg, Sweden.
    Lofgren, Monika
    Danderyd Hospital Stockholm, Sweden.
    Bileviciute-Ljungar, Indre
    Danderyd Hospital Stockholm, Sweden.
    Bjersing, Jan
    University of Gothenburg, Sweden.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Kosek, Eva
    Karolinska Institute, Sweden.
    Mannerkorpi, Kaisa
    University of Gothenburg, Sweden.
    Resistance exercise improves physical fatigue in women with fibromyalgia: a randomized controlled trial2016In: Arthritis Research & Therapy, ISSN 1478-6354, E-ISSN 1478-6362, Vol. 18, no 176Article in journal (Refereed)
    Abstract [en]

    Background: Fibromyalgia (FM) affects approximately 1-3 % of the general population. Fatigue limits the work ability and social life of patients with FM. A few studies of physical exercise have included measures of fatigue in FM, indicating that exercise can decrease fatigue levels. There is limited knowledge about the effects of resistance exercise on multiple dimensions of fatigue in FM. The present study is a sub-study of a multicenter randomized controlled trial in women with FM. The purpose of the present sub-study was to examine the effects of a person-centered progressive resistance exercise program on multiple dimensions of fatigue in women with FM, and to investigate predictors of the potential change in fatigue. Methods: A total of 130 women with FM (age 22-64 years) were included in this assessor-blinded randomized controlled multicenter trial examining the effects of person-centered progressive resistance exercise compared with an active control group. The intervention was performed twice a week for 15 weeks. Outcomes were five dimensions of fatigue measured with the Multidimensional Fatigue Inventory (MFI-20). Information about background was collected and the women also completed several health-related questionnaires. Multiple linear stepwise regression was used to analyze predictors of change in fatigue in the total population. Results: A higher improvement was found at the post-treatment examination for change in the resistance exercise group, as compared to change in the active control group in the MFI-20 subscale of physical fatigue (resistance group Delta -1.7, SD 4.3, controls Delta 0.0, SD 2.7, p = 0.013), with an effect size of 0.33. Sleep efficiency was the strongest predictor of change in the MFI-20 subscale general fatigue (beta = -0.54, p = 0.031, R-2 = 0.05). Participating in resistance exercise (beta = 1.90, p = 0.010) and working fewer hours per week (beta = 0.84, p = 0.005) were independent significant predictors of change in physical fatigue (R-2 = 0.14). Conclusions: Person-centered progressive resistance exercise improved physical fatigue in women with FM when compared to an active control group.

  • 58.
    Ernberg, M.
    et al.
    Karolinska Institutet, Huddinge, Sweden.
    Castrillon, E.E.
    Aarhus University, Denmark.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre. Östergötlands Läns Landsting, Heart and Medicine Centre, Occupational and Environmental Medicine Centre.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    List, T.
    Malmö University, Sweden.
    Svensson, P.
    Aarhus University and Aarhus University Hospital, Denmark.
    Experimental myalgia induced by repeated infusion of acidicsaline into the human masseter muscle does not cause the release of algesic substances2013In: European Journal of Pain, ISSN 1090-3801, E-ISSN 1532-2149, Vol. 17, no 4, p. 539-550Article in journal (Refereed)
    Abstract [en]

    BACKGROUND:

    Animal studies have shown that two repeated intramuscular injections of acidic saline induce mechanical allodynia that lasts for 4 weeks with spread to the contralateral side. In this study, we tested the hypothesis that two repeated intramuscular infusions of acidic saline into the human masseter muscle is associated with pain, mechanical allodynia and release of algesic substances. Eighteen healthy volunteers participated. On day 1, 2.5 mL of acidic saline (pH 3.3) was infused into one of the masseter muscles and isotonic saline (pH 6.0) into the other (randomized and single-blind). Two days later, intramuscular microdialysis was performed to sample serotonin, glutamate, pyruvate, lactate and glucose, during which the saline infusions were repeated. Pain and pressure pain thresholds (PPTs) were recorded before and after infusions on both days.

    RESULTS:

    Pain intensity induced by the infusions was higher after acidic than that after isotonic saline (p < 0.05). PPTs were decreased on both sides after microdialysis compared with baseline day 1 (p's < 0.05), but there were no differences in PPTs between sides at any time point. The levels of serotonin, glutamate, pyruvate, lactate or glucose did not change significantly during microdialysis.

    CONCLUSION:

    Infusion of acidic saline caused low levels of muscle pain, but no mechanical allodynia and no increased release of algesic substances. The value of this model appears modest, but future studies could be performed with larger sample size and higher flow rate before definite conclusions about the validity of the model for craniofacial myalgia can be drawn.

  • 59.
    Ernberg, M.
    et al.
    Karolinska Inst, Sweden; SCON, Sweden.
    Christidis, N.
    Karolinska Inst, Sweden; SCON, Sweden.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Bileviciute-Ljungar, I.
    Karolinska Inst, Sweden; Danderyd Hosp, Sweden.
    Lofgren, M.
    Karolinska Inst, Sweden; Danderyd Hosp, Sweden.
    Bjersing, J.
    Univ Gothenburg, Sweden.
    Palstam, A.
    Univ Gothenburg, Sweden.
    Larsson, A.
    Univ Gothenburg, Sweden.
    Mannerkorpi, K.
    Univ Gothenburg, Sweden.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Kosek, E.
    Karolinska Inst, Sweden; Stockholm Spine Ctr, Sweden.
    Plasma Cytokine Levels in Fibromyalgia and Their Response to 15 Weeks of Progressive Resistance Exercise or Relaxation Therapy2018In: Mediators of Inflammation, ISSN 0962-9351, E-ISSN 1466-1861, article id 3985154Article in journal (Refereed)
    Abstract [en]

    The aims of this study were to compare circulating cytokines between FM and healthy controls and to investigate the effect on cytokine levels by 15 weeks of progressive resistance exercise or relaxation therapy in FM. Baseline plasma cytokine levels and clinical data were analyzed in 125 women with FM and 130 age-matched healthy women. The FM women were then randomized to progressive resistance exercise (n = 49) or relaxation (n = 43). Baseline IL-2, IL-6, TNF-alpha, IP-10, and eotaxin were higher in FM than in healthy controls (P amp;lt; 0.041), whereas IL-beta was lower (P amp;lt; 0.001). There were weak correlations between cytokine levels and clinical variables. After both interventions, IL-1ra had increased (P=0.004), while IL-1 beta had increased in the relaxation group (P = 0.002). Changes of IFN-gamma, IL-2, IL-4, IL-6, IL-8, and IL-17A were weakly correlated with changes of PPT, but there were no significant correlations between changes of cytokine and changes in other clinical variables. The elevated plasma levels of several cytokines supports the hypothesis that chronic systemic inflammation may underlie the pathophysiology of FM even if the relation to clinical variables was weak. However, 15 weeks of resistance exercise, as performed in this study, did not show any anti-inflammatory effect on neither FM symptoms nor clinical and functional variables.

  • 60.
    Ernberg, Malin
    et al.
    Karolinska Institute, Sweden; SCON, Sweden.
    Christidis, Nikolaos
    Karolinska Institute, Sweden; SCON, Sweden.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Bileviciute-Ljungar, Indre
    Karolinska Institute, Sweden; Danderyd Hospital, Sweden.
    Löfgren, Monika
    Karolinska Institute, Sweden; Danderyd Hospital, Sweden.
    Larsson, Anette
    University of Gothenburg, Sweden; University of Gothenburg, Sweden.
    Palstam, Annie
    University of Gothenburg, Sweden.
    Bjersing, Jan
    University of Gothenburg, Sweden.
    Mannerkorpi, Kaisa
    University of Gothenburg, Sweden; University of Gothenburg, Sweden.
    Kosek, Eva
    Karolinska Institute, Sweden; Stockholm Spine Centre, Sweden.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Effects of 15 weeks of resistance exercise on pro-inflammatory cytokine levels in the vastus lateralis muscle of patients with fibromyalgia2016In: Arthritis Research & Therapy, ISSN 1478-6354, E-ISSN 1478-6362, Vol. 18, no 137Article in journal (Refereed)
    Abstract [en]

    Background: This study aimed at investigating the effect of a resistance exercise intervention on the interstitial muscle levels of pro-inflammatory cytokines in fibromyalgia (FMS) and healthy controls (CON). Methods: Twenty-four female patients with FMS (54 +/- 8 years) and 27 female CON (54 +/- 9 years) were subjected to intramuscular microdialysis of the most painful vastus lateralis muscle before and after 15 weeks of progressive resistance exercise twice per week. Baseline dialysates were sampled in the resting muscle 140 min after insertion of the microdialysis catheter. The participants then performed repetitive dynamic contractions (knee extension) for 20 min, followed by 60 min rest. Pain intensity was assessed with a 0-100 mm visual analogue scale (VAS), and fatigue was assessed with Borgs RPE throughout microdialysis. Dialysates were sampled every 20 min and analyzed with Luminex for interleukin (IL)-1 beta, tumor necrosis factor (TNF) alpha, IL-6, and IL-8. Results: At both sessions and for both groups the dynamic contractions increased pain (P amp;lt; 0.012) and fatigue (P amp;lt; 0.001). The levels of TNF were lower in the FMS group than the CON group at both sessions (P amp;lt; 0.05), but none of the other cytokines differed between the groups. IL-6 and IL-8 increased after the dynamic contractions in both groups (P amp;lt; 0.010), while TNF increased only in CON (P amp;lt; 0.05) and IL-1 beta did not change. Overall pain intensity was reduced after the 15 weeks of resistance exercise in FMS (P amp;lt; 0.05), but there was no changes in fatigue or cytokine levels. Conclusion: Progressive resistance exercise for 15 weeks did not affect the interstitial levels of IL-1 beta, TNF, IL-6, and IL-8 in the vastus lateralis muscle of FMS patients or CON.

  • 61.
    Ertzgaard, Per
    et al.
    Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Rehabilitation Medicine. Linköping University, Department of Medical and Health Sciences, Division of Community Medicine.
    Ohberg, Fredrik
    Umeå University, Sweden.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Grip, Helena
    Umeå University, Sweden.
    A new way of assessing arm function in activity using kinematic Exposure Variation Analysis and portable inertial sensors - A validity study2016In: Manual Therapy, ISSN 1356-689X, E-ISSN 1532-2769, Vol. 21, p. 241-249Article in journal (Refereed)
    Abstract [en]

    Portable motion systems based on inertial motion sensors are promising methods, with the advantage compared to optoelectronic cameras of not being confined to a laboratory setting. A challenge is to develop relevant outcome measures for clinical use. The aim of this study was to characterize elbow and shoulder motion during functional tasks, using portable motion sensors and a modified Exposure Variation Analysis (EVA) and evaluate system accuracy with optoelectronic cameras. Ten healthy volunteers and one participant with sequel after stroke performed standardised functional arm tasks. Motion was registered simultaneously with a custom developed motion sensor system, including gyroscopes and accelerometers, and an optoelectronic camera system. The EVA was applied on elbow and shoulder joints, and angular and angular velocity EVA plots was calculated. The EVA showed characteristic patterns for each arm task in the healthy controls and a distinct difference between the affected and unaffected arm in the participant with sequel after stroke. The accuracy of the portable system was high with a systematic error ranging between -1.2 degrees and 2.0 degrees. The error was direction specific due to a drift component along the gravity vector. Portable motion sensor systems have high potential as clinical tools for evaluation of arm function. EVA effectively illustrates joint angle and joint angle velocity patterns that may capture deficiencies in arm function and movement quality. Next step will be to manage system drift by including magnetometers, to further develop clinically relevant outcome variables and apply this for relevant patient groups. (C) 2015 Elsevier Ltd. All rights reserved.

  • 62.
    Gerdle, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Förekomst av kroniska/långvariga smärtor2006In: Rehabiliteringsmedicin Teori och praktik / [ed] Jörgen Borg,Björn Gerdle, Gunnar Grimby, Katharina Stibrant Sunnerhagen, Lund: Studenltitteratur , 2006, 1, p. 73-77Chapter in book (Other academic)
    Abstract [sv]

        Kapitel om rehabiliteringsmedicinens utveckling och nuvarande plats i sjukvården samt begrepp och metodik inleder boken. I två delar ges därefter rehabiliteringsmedicinska aspekter på de dominerande sjukdomsgrupperna - komplexa smärttillstånd respektive skador och sjukdomar i nervsystemet. Som avslutning beskrivs bland annat  stressrelaterade tillstånd. Läroboken är avsedd för grundutbildning av läkare, arbetsterapeuter och sjukgymnaster, logopeder samt för läkare under AT-tjänstgöring. Den är också lämplig som introduktion i specialistutbildningen i rehabiliteringsmedicin, geriatrik, neurologi och smärtlindring. Vidareutbildningar av olika vårdyrkesgrupper kan ha nytta av boken och den kan också användas som referenslitteratur av yrkesverksamma med intresse för rehabiliteringsmedicin.

  • 63.
    Gerdle, Björn
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Akerblom, Sophia
    Skane Univ Hosp, Sweden; Lund Univ, Sweden.
    Jansen, Gunilla Brodda
    Danderyd Hosp, Sweden.
    Enthoven, Paul
    Linköping University, Department of Medical and Health Sciences, Division of Physiotherapy. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in West Östergötland, Research & Development Unit in Local Health Care.
    Ernberg, Malin
    Karolinska Inst, Sweden; SCON, Sweden.
    Dong, Huan-Ji
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Stalnacke, Britt-Marie
    Umea Univ, Sweden.
    Ang, Bjorn O.
    Karolinska Inst, Sweden; Uppsala Univ, Sweden; Dalarna Univ, Sweden.
    Boersma, Katja
    Orebro Univ, Sweden.
    Who benefits from multimodal rehabilitation - an exploration of pain, psychological distress, and life impacts in over 35,000 chronic pain patients identified in the Swedish Quality Registry for Pain Rehabilitation2019In: Journal of Pain Research, ISSN 1178-7090, E-ISSN 1178-7090, Vol. 12, p. 891-908Article in journal (Refereed)
    Abstract [en]

    Background: Chronic pain patients frequently suffer from psychological symptoms. There is no consensus concerning the prevalence of severe anxiety and depressive symptoms and the strength of the associations between pain intensity and psychological distress. Although an important aspect of the clinical picture is understanding how the pain condition impacts life, little is known about the relative importance of pain and psychological symptoms for individuals life impact. The aims of this study were to identify subgroups of pain patients; to analyze if pain, psychological distress, and life impact variables influence subgrouping; and to investigate how patients in the subgroups benefit from treatments. Methods: Background variables, pain aspects (intensity/severity and spreading), psychological distress (depressive and anxiety symptoms), and two life impact variables (pain interference and perceived life control) were obtained from the Swedish Quality Registry for Pain Rehabilitation for chronic pain patients and analyzed mainly using advanced multivariate methods. Results: Based on amp;gt;35,000 patients, 35%-40% had severe anxiety or depressive symptoms. Severe psychological distress was associated with being born outside Europe (21%-24% vs 6%-8% in the category without psychological distress) and low education level (20.7%-20.8% vs 26%-27% in the category without psychological distress). Dose relationships existed between the two psychological distress variables and pain aspects, but the explained variances were generally low. Pain intensity/severity and the two psychological distress variables were significantly associated (R-2 =0.40-0.48; Pamp;gt;0.001) with the two life impact variables (pain interference and life control). Two subgroups of patients were identified at baseline (subgroup 1: n=15,901 16,119; subgroup 2: n=20,690-20,981) and the subgroup with the worst situation regarding all variables participated less in an MMRP (51% vs 58%, Pamp;lt;0.001) but showed the largest improvements in outcomes. Conclusion: The results emphasize the need to assess both pain and psychological distress and not take for granted that pain involves high psychological stress in the individual case. Not all patients benefit from MMRP. A better matching between common clinical pictures and the content of MMRPs may help improve results. We only partly found support for treatment resistance in patients with psychological distress burden.

  • 64.
    Gerdle, Björn
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Akerblom, Sophia
    Skane Univ Hosp, Sweden; Lund Univ, Sweden.
    Stålnacke, Britt-Marie
    Umea Univ, Sweden.
    Brodda Jansen, Gunilla
    Danderyd Hosp, Sweden.
    Enthoven, Paul
    Linköping University, Department of Medical and Health Sciences, Division of Physiotherapy. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in West Östergötland, Research & Development Unit in Local Health Care.
    Ernberg, Malin
    Karolinska Inst, Sweden; SCON, Sweden.
    Dong, Huan-Ji
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Ang, Bjorn O.
    Karolinska Inst, Sweden; Uppsala Univ, Sweden; Dalarna Univ, Sweden.
    Boersma, Katja
    Orebro Univ, Sweden.
    The importance of emotional distress, cognitive behavioural factors and pain for life impact at baseline and for outcomes after rehabilitation - a SQRP study of more than 20,000 chronic pain patients2019In: Scandinavian Journal of Pain, ISSN 1877-8860, E-ISSN 1877-8879, Vol. 19, no 4, p. 693-711Article in journal (Refereed)
    Abstract [en]

    Background and aims: Although literature concerning chronic pain patients indicates that cognitive behavioural variables, specifically acceptance and fear of movement/(re)injury, are related to life impact, the relative roles of these factors in relation to pain characteristics (e.g. intensity and spreading) and emotional distress are unclear. Moreover, how these variables affect rehabilitation outcomes in different subgroups is insufficiently understood. This study has two aims: (1) to investigate how pain, cognitive behavioural, and emotional distress variables intercorrelate and whether these variables can regress aspects of life impact and (2) to analyse whether these variables can be used to identify clinically meaningful subgroups at baseline and which subgroups benefit most from multimodal rehabilitation programs (MMRP) immediately after and at 12-month follow-up. Methods: Pain aspects, background variables, psychological distress, cognitive behavioural variables, and two life impact variables were obtained from the Swedish Quality Registry for Pain Rehabilitation (SQRP) for chronic pain patients. These data were analysed mainly using advanced multivariate methods. Results: The study includes 22,406 chronic pain patients. Many variables, including acceptance variables, showed important contributions to the variation in clinical presentations and in life impacts. Based on the statistically important variables considering the clinical presentation, three clusters/subgroups of patients were identified at baseline; from the worst clinical situation to the relatively good situation. These clusters showed significant differences in outcomes after participating in MMRP; the subgroup with the worst situation at baseline showed the most significant improvements. Conclusions: Pain intensity/severity, emotional distress, acceptance, and life impacts were important for the clinical presentation and were used to identify three clusters with marked differences at baseline (i.e. before MMRP). Life impacts showed complex relationships with acceptance, pain intensity/severity, and emotional distress. The most significant improvements after MMRP were seen in the subgroup with the lowest level of functioning before treatment, indicating that patients with complex problems should be offered MMRP.

  • 65.
    Gerdle, Björn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Björk, Jonas
    Competence Centre for Clinical Research Lund University Hospital.
    Cöster, Lars
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Rheumatology . Östergötlands Läns Landsting, Centre for Medicine, Department of Rheumatology in Östergötland.
    Henriksson, Karl-Gösta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Henriksson, Chris
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Social and Welfare Studies.
    Bengtsson, Ann
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Rheumatology . Östergötlands Läns Landsting, Centre for Medicine, Department of Rheumatology in Östergötland.
    Prevalence of widespread pain and associations with work status: A population study2008In: BMC Musculoskeletal Disorders, ISSN 1471-2474, E-ISSN 1471-2474, Vol. 9Article in journal (Refereed)
    Abstract [en]

    Background. This population study based on a representative sample from a Swedish county investigates the prevalence, duration, and determinants of widespread pain (WSP) in the population using two constructs and estimates how WSP affects work status. In addition, this study investigates the prevalence of widespread pain and its relationship to pain intensity, gender, age, income, work status, citizenship, civil status, urban residence, and health care seeking. Methods. A cross-sectional survey using a postal questionnaire was sent to a representative sample (n = 9952) of the target population (284,073 people, 18-74 years) in a county (Östergötland) in the southern Sweden. The questionnaire was mailed and followed by two postal reminders when necessary. Results. The participation rate was 76.7% (n = 7637), the non-participants were on the average younger, earned less money, and male. Women had higher prevalences of pain in 10 different predetermined anatomical regions. WSP was generally chronic (90-94%) and depending on definition of WSP the prevalence varied between 4.8-7.4% in the population. Women had significantly higher prevalence of WSP than men and the age effect appeared to be stronger in women than in men. WSP was a significant negative factor - together with age 50-64 years, low annual income, and non-Nordic citizen - for work status in the community and in the group with chronic pain. Chronic pain but not the spreading of pain was related to health care seeking in the population. Conclusion. This study confirms earlier studies that report high prevalences of widespread pain in the population and especially among females and with increasing age. Widespread pain is associated with prominent effects on work status. © 2008 Gerdle et al, licensee BioMed Central Ltd.

  • 66.
    Gerdle, Björn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Björk, Jonas
    Lunds Universitet.
    Henriksson, Chris
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Occupational Therapy.
    Bengtsson, Ann
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Rheumatology. Östergötlands Läns Landsting, Centre for Medicine, Department of Rheumatology in Östergötland.
    Prevalence of current and chronic pain and their influences upon work and healthcare-seeking: A population study2004In: Journal of Rheumatology, ISSN 0315-162X, E-ISSN 1499-2752, Vol. 31, no 7, p. 1399-1406Article in journal (Refereed)
    Abstract [en]

    Objective. To investigate the prevalence of current and chronic pain and their relationship to pain intensity, sex, age, income, employment status, citizenship, marital status, urban residence, occupational activity, and healthcare-seeking based on a representative sample from a Swedish county. Methods. A cross-sectional survey using a postal questionnaire was sent to a representative sample (n = 9952) of the target population (284,073 people, age 18-74 yrs) in a county (Östergötland) in southern Sweden. A questionnaire was mailed and followed by 2 postal reminders if necessary. Results. The participation rate was 76.7% (n = 7637), nonparticipants were on average younger, male, and earned less money. The overall point prevalence of pain was 48.9%. The corresponding one-month period prevalence was 63.0%, and pain on several occasions during the previous 3 months was reported by 61.3% of participants. The prevalence of chronic pain (pain > 3 months) was 53.7%. Female sex, age, and sick leave/early retirement were generally of significant importance in the regressions of pain. No sex factor was found in the regressions of pain frequency and pain intensity. Chronic pain - especially frequent and intensive pain - showed clear associations with healthcare-seeking and occupational activity. Conclusion. High prevalence of current pain (48.9%) and chronic pain (53.7%) were found in this community-based study. Being female, older, and on sick leave or early retirement were generally of significant importance in the regressions of pain. Chronic pain showed clear associations with healthcare-seeking and occupational activity, indicating considerable socioeconomic costs.

  • 67.
    Gerdle, Björn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Boivie, Jörgen
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Neurology. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Johansson, Eva
    Umeå Universitet.
    Inledning2006In: Metoder för behandling av långvarig smärta - en systematisk litteraturöversikt / [ed] Statens beredning för medicinsk utvärdering, Stockholm: Statens beredning för medicinsk utvärdering (SBU) , 2006, 2, p. 47-107Chapter in book (Other academic)
    Abstract [sv]

      

    Syftet med rapporten är att sammanfatta det vetenskapliga underlaget rörande effekter, biverkningar samt kostnadseffektivitet för metoder som används för att behandla långvarig, icke-cancerrelaterad smärta. Behandling som innebär öppen kirurgi har exkluderats från genomgången.

  • 68.
    Gerdle, Björn
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Ernberg, Malin
    Karolinska Institute, Department of Dental Medicine, Section of Orofacial Pain and Jaw Function / Scandinavian Centre for Orofacial Neuroscience (SCON), Stockholm, Sweden.
    Mannerkorpi, Kaisa
    Section of Physiotherapy, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden / University of Gothenburg Centre for Person-Centred Care (GPCC), Sahlgrenska Academy, Gothenburg, Sweden.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Kosek, Eva
    Department of Clinical Neuroscience and Osher Centre for Integrative Medicine, Karolinska Institute, Stockholm, Sweden.
    Christidis, Nikolaos
    Karolinska Institute, Department of Dental Medicine, Section of Orofacial Pain and Jaw Function / Scandinavian Centre for Orofacial Neuroscience (SCON), Stockholm, Sweden.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Increased Interstitial Concentrations of Glutamate and Pyruvate in Vastus Lateralis of Women with Fibromyalgia Syndrome Are Normalized after an Exercise Intervention: a Case-Control Study2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 10, p. 14article id e0162010Article in journal (Refereed)
    Abstract [en]

    Background Fibromyalgia syndrome (FMS) is associated with central alterations, but controversies exist regarding the presence and role of peripheral factors. Microdialysis (MD) can be used in vivo to study muscle alterations in FMS. Furthermore for chronic pain conditions such as FMS, the mechanisms for the positive effects of exercise are unclear. This study investigates the interstitial concentrations of algesics and metabolites in the vastus lateralis muscle of 29 women with FMS and 28 healthy women before and after an exercise intervention. Methods All the participants went through a clinical examination and completed a questionnaire. In addition, their pressure pain thresholds (PPTs) in their upper and lower extremities were determined. For both groups, MD was conducted in the vastus lateralis muscle before and after a 15-week exercise intervention of mainly resistance training of the lower limbs. Muscle blood flow and interstitial muscle concentrations of lactate, pyruvate, glutamate, glucose, and glycerol were determined. Results FMS was associated with significantly increased interstitial concentrations of glutamate, pyruvate, and lactate. After the exercise intervention, the FMS group exhibited significant decreases in pain intensity and in mean interstitial concentrations of glutamate, pyruvate, and glucose. The decrease in pain intensity in FMS correlated significantly with the decreases in pyruvate and glucose. In addition, the FMS group increased their strength and endurance. Conclusion This study supports the suggestion that peripheral metabolic and algesic muscle alterations are present in FMS patients and that these alterations contribute to pain. After an exercise intervention, alterations normalized, pain intensity decreased (but not abolished), and strength and endurance improved, all findings that suggest the effects of exercise are partially peripheral.

  • 69.
    Gerdle, Björn
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Ernberg, Malin
    Karolinska Institute, Department of Dental Medicine, Section of Orofacial Pain and Jaw Function / Scandinavian Centre for Orofacial Neuroscience (SCON), Stockholm, Sweden.
    Mannerkorpi, Kaisa
    Section of Physiotherapy, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden / University of Gothenburg Centre for Person-Centred Care (GPCC), Sahlgrenska Academy, Gothenburg, Sweden.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Kosek, Eva
    Department of Clinical Neuroscience and Osher Centre for Integrative Medicine, Karolinska Institute, Stockholm, Sweden.
    Christidis, Nikolaos
    Karolinska Institute, Department of Dental Medicine, Section of Orofacial Pain and Jaw Function / Scandinavian Centre for Orofacial Neuroscience (SCON), Stockholm, Sweden.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Increased Interstitial Concentrations of Glutamate and Pyruvate in Vastus Lateralis of Women with Fibromyalgia Syndrome Are Normalized after an Exercise Intervention: a Case-Control Study2016Data set
  • 70.
    Gerdle, Björn
    et al.
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Forsgren, Mikael
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Bengtsson, Ann
    Linköping University, Department of Clinical and Experimental Medicine, Rheumatology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Rheumatology.
    Dahlqvist Leinhard, Olof
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Sören, B.
    Linköping University, Department of Clinical and Experimental Medicine, Rheumatology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Rheumatology.
    Karlsson, Anette
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, Faculty of Health Sciences.
    Brandejsky, Vaslav
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Lund, Eva
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics. Östergötlands Läns Landsting, Center for Diagnostics, Department of Radiology in Linköping.
    Decreased muscle concentrations of ATP and PCR in the quadriceps muscle of fibromyalgia patients – A 31P-MRS study2013In: European Journal of Pain, ISSN 1090-3801, E-ISSN 1532-2149, Vol. 17, no 8, p. 1205-1215Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND METHODS:

    Fibromyalgia (FMS) has a prevalence of approximately 2% in the population. Central alterations have been described in FMS, but there is not consensus with respect to the role of peripheral factors for the maintenance of FMS. 31P magnetic resonance spectroscopy (31P-MRS) has been used to investigate the metabolism of phosphagens in muscles of FMS patients, but the results in the literature are not in consensus. The aim was to investigate the quantitative content of phosphagens and pH in resting quadriceps muscle of patients with FMS (n = 19) and in healthy controls (Controls; n = 14) using (31) P-MRS. It was also investigated whether the concentrations of these substances correlated with measures of pain and/or physical capacity.

    RESULTS:

    Significantly lower concentrations of adenosine triphosphate (ATP) and phosphocreatinine (PCr; 28-29% lower) were found in FMS. No significant group differences existed with respect to inorganic phosphate (Pi), Pi/PCr and pH. The quadriceps muscle fat content was significantly higher in FMS than in Controls [FMS: 9.0 ± 0.5% vs. Controls: 6.6 ± 0.6%; (mean ± standard error); P = 0.005]. FMS had significantly lower hand and leg capacity according to specific physical test, but there were no group differences in body mass index, subjective activity level and in aerobic fitness. In FMS, the specific physical capacity in the leg and the hand correlated positively with the concentrations of ATP and PCr; no significant correlations were found with pain intensities.

    CONCLUSIONS:

    Alterations in intramuscular ATP, PCr and fat content in FMS probably reflect a combination of inactivity related to pain and dysfunction of muscle mitochondria.

  • 71.
    Gerdle, Björn
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Östergötlands Läns Landsting, Heart and Medicine Center, Occupational and Environmental Medicine Center.
    Ernberg, Malin
    Karolinska Institutet, Huddinge, Sweden.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Chronic musculoskeletal pain: review of mechanisms and biochemical biomarkers as assessed by the microdialysis technique2014In: Journal of Pain Research, ISSN 1178-7090, E-ISSN 1178-7090, Vol. 7, p. 313-326Article, review/survey (Refereed)
    Abstract [en]

    Chronic musculoskeletal pain conditions are multifaceted, and approximately 20% of the adult population lives with severe chronic pain, with a higher prevalence in women and in lower income groups. Chronic pain is influenced by and interacts with physical, emotional, psychological, and social factors, and a biopsychosocial framework is increasingly applied in clinical practice. However, there is still a lack of assessment procedures based on the activated neurobiological pain mechanisms (ie, the biological part of the biopsychosocial model of pain), which may be a necessary step for further optimizing outcomes after treatments for patients with chronic pain. It has been suggested that chronic pain conditions are mainly driven by alterations in the central nervous system with little or no peripheral stimuli or nociception. In contrast, other authors argue that such central alterations are driven by peripheral alterations and nociceptive input. Microdialysis is an in vivo method for studying local tissue alterations and allows for sampling of substances in the interstitium of the muscle, where nociceptor free nerve endings are found close to the muscle fibers. The extracellular matrix plays a key role in physiologic functions of cells, including the primary afferent nociceptor. The present review mainly concerns the results of microdialysis studies and how they can contribute to the understanding of activated peripheral nociceptive and pain mechanisms in humans with chronic pain. The primary aim was to review molecular studies using microdialysis for the investigation of human chronic muscle pain, ie, chronic masticatory muscle pain, chronic trapezius myalgia, chronic whiplash-associated disorders, and chronic widespread pain/fibromyalgia syndrome. Several studies clearly showed elevated levels of serotonin, glutamate, lactate, and pyruvate in localized chronic myalgias and may be potential biomarkers. These results indicate that peripheral muscle alterations are parts of the activated pain mechanisms in common chronic pain conditions. Muscle alterations have been reported in fibromyalgia syndrome and chronic widespread pain, but more studies are needed before definite conclusions can be drawn. For other substances, results are inconclusive across studies and patient groups.

  • 72.
    Gerdle, Björn
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Ghafouri, Nazdar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Bäckryd, Emmanuel
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Gordh, Torsten
    Uppsala University, Sweden.
    Signs of ongoing inflammation in female patients with chronic widespread pain A multivariate, explorative, cross-sectional study of blood samples2017In: Medicine (Baltimore, Md.), ISSN 0025-7974, E-ISSN 1536-5964, Vol. 96, no 9, article id e6130Article in journal (Refereed)
    Abstract [en]

    This cross-sectional study investigates the plasma inflammatory profile of chronic widespread pain CWP) patients compared to healthy controls CON). Rather than analyzing a relatively few substances at a time, we used a new multiplex proximity extension assay PEA) panel that enabled the simultaneous analysis of 92 inflammation-related proteins, mainly cytokines and chemokines. Seventeen women with CWP and 21 female CON participated and a venous blood sample was drawn from all subjects. Pain intensity and pain thresholds for pressure, heat, and cold were registered. A PEA panel 92 proteins) was used to analyze the blood samples. Multivariate data analysis by projection was used in the statistical analyses. Eleven proteins significantly differentiated the CON and CWP subjects R-2=0.58, Q(2)=0.37, analysis of variance of cross-validated predictive residuals P=0.006). It was not possible to significantly regress pain thresholds within each group CON or CWP). Positive significant correlations existed between several proteins and pain intensities in CWP, but the model reliability of the regression was poor. CWP was associated with systemic low-grade inflammation. Larger studies are needed to confirm the results and to investigate which alterations are condition-specific and which are common across chronic pain conditions. The presence of inflammation could promote the spreading of pain, a hallmark sign of CWP. As it has been suggested that prevalent comorbidities to pain (e.g., depression and anxiety, poor sleep, and tiredness) also are associated with inflammation, it will be important to determine whether inflammation may be a common mediator.

  • 73.
    Gerdle, Björn
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Gronlund, Christer
    Umeå University Hospital.
    Karlsson, Stefan J
    Umeå University Hospital.
    Holtermann, Andreas
    National Research Centre Working Environment, Copenhagen.
    Roeleveld, Karin
    Norwegian University Science and Technology.
    Altered neuromuscular control mechanisms of the trapezius muscle in fibromyalgia2010In: BMC MUSCULOSKELETAL DISORDERS, ISSN 1471-2474, Vol. 11, no 42Article in journal (Refereed)
    Abstract [en]

    Background: fibromyalgia is a relatively common condition with widespread pain and pressure allodynia, but unknown aetiology. For decades, the association between motor control strategies and chronic pain has been a topic for debate. One long held functional neuromuscular control mechanism is differential activation between regions within a single muscle. The aim of this study was to investigate differences in neuromuscular control, i.e. differential activation, between myalgic trapezius in fibromyalgia patients and healthy controls. Methods: 27 fibromyalgia patients and 30 healthy controls performed 3 minutes bilateral shoulder elevations with different loads (0-4 Kg) with a high-density surface electromyographical (EMG) grid placed above the upper trapezius. Differential activation was quantified by the power spectral median frequency of the difference in EMG amplitude between the cranial and caudal parts of the upper trapezius. The average duration of the differential activation was described by the inverse of the median frequency of the differential activations. Results: the median frequency of the differential activations was significantly lower, and the average duration of the differential activations significantly longer in fibromyalgia compared with controls at the two lowest load levels (0-1 Kg) (p andlt; 0.04), but not at the two highest load levels (2 and 4 Kg). Conclusion: these findings illustrate a different neuromuscular control between fibromyalgia patients and healthy controls during a low load functional task, either sustaining or resulting from the chronic painful condition. The findings may have clinical relevance for rehabilitation strategies for fibromyalgia.

  • 74.
    Gerdle, Björn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Gullacksen, Ann-Christine
    Malmö Högskola.
    Multimodal rehabilitering2006In: Metoder för behandling av långvarig smärta - En systematisk litteraturöversikt / [ed] Statens beredning för medicinsk utvärdering, Stockholm: Statens beredning för medicinsk utvärdering (SBU) , 2006, 2, p. 159-213Chapter in book (Other academic)
    Abstract [sv]

    Syftet med rapporten är att sammanfatta det vetenskapliga underlaget rörande effekter, biverkningar samt kostnadseffektivitet för metoder som används för att behandla långvarig, icke-cancerrelaterad smärta. Behandling som innebär öppen kirurgi har exkluderats från genomgången.

  • 75.
    Gerdle, Björn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Gullacksen, Ann-Christine
    Malmö Högskola.
    Rehabilitering vid kronisk smärta-särskilt multimodal rehabiltiering2006In: Rehabiliteringsmedicin - Teori och praktik / [ed] Jörgen Borg,Björn Gerdle, Gunnar Grimby, Katharina Stibrant Sunnerhagen, Lund: Studentlitteratur , 2006, 1, p. 97-107Chapter in book (Other academic)
    Abstract [sv]

      Kapitel om rehabiliteringsmedicinens utveckling och nuvarande plats i sjukvården samt begrepp och metodik inleder boken. I två delar ges därefter rehabiliteringsmedicinska aspekter på de dominerande sjukdomsgrupperna - komplexa smärttillstånd respektive skador och sjukdomar i nervsystemet. Som avslutning beskrivs bland annat  stressrelaterade tillstånd. Läroboken är avsedd för grundutbildning av läkare, arbetsterapeuter och sjukgymnaster, logopeder samt för läkare under AT-tjänstgöring. Den är också lämplig som introduktion i specialistutbildningen i rehabiliteringsmedicin, geriatrik, neurologi och smärtlindring. Vidareutbildningar av olika vårdyrkesgrupper kan ha nytta av boken och den kan också användas som referenslitteratur av yrkesverksamma med intresse för rehabiliteringsmedicin.

  • 76.
    Gerdle, Björn
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Hilgenfeldt, Ulrich
    University of Heidelberg.
    Larsson, Britt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Kristiansen, Jesper
    National Research Centre for the Working Environment.
    Sogaard, Karen
    National Research Centre for the Working Environment.
    Rosendal, Lars
    Cyncron A/S.
    Bradykinin and kallidin levels in the trapezius muscle in patients with work-related trapezius myalgia, in patients with whiplash associated pain, and in healthy controls - A microdialysis study of women2008In: PAIN, ISSN 0304-3959, Vol. 139, no 3, p. 578-587Article in journal (Refereed)
    Abstract [en]

    The origins of chronic Muscle pain development and maintenance are debated regarding the relative contributions of peripheral nociception and central pain processing. Bradykinin (BKN) and kallidin (KAL) have been suggested to be algesic kinins involved in muscle pain. This in vivo study investigates whether there were significant differences in interstitial muscle concentrations of BKN and KAL between chronic work-related trapezius myalgia (TM), chronic whiplash associated disorders (WAD), and healthy controls (CON). These subjects were studied Lit rest, during a 20-min repetitive low-force exercise and recovery. The interstitial concentrations of BKN and KAL of trapezius were determined using the microdialysis technique. The interstitial concentration of KAL was overall significantly higher in TM than in CON. [KAL] and [BKN] increased significantly during the brief exercise in all groups. The increase in [BKN] during exercise was significantly higher in TM than in the other two groups,whereas the increase in [KAL] during exercise was highest in WAD. In chronic pain, positive correlations existed between the two kinins and the difference in pain intensity between recovery and baseline. In this in vivo study of two groups of patients with chronic pain clinically involving the trapezius muscle, we found alterations - most prominent in TM in the interstitial concentrations of BKN and KAL. The results indicated that the two kinins were involved in aspects of hyperalgesia.

  • 77.
    Gerdle, Björn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Karlsson, S
    Crenshaw, AG
    Elert, Jessica
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Department of Health and Society, Division of Physiotherapy.
    Fridén, J
    The influences of muscle fibre proportions and areas upon EMG during maximal dynamic knee extensions2000In: European Journal of Applied Physiology and Occupational Physiology, ISSN 0301-5548, E-ISSN 1432-1025, Vol. 81, no 1-2Article in journal (Refereed)
    Abstract [en]

    This study is an investigation of the relationship between muscle morphology and surface electromyographic (EMG) parameters [mean frequency of the power spectrum (MNF), signal amplitude (root mean square, RMS) and the signal amplitude ratio (SAR, i.e. the ratio between the RMS level during the passive part of the contraction cycle and the RMS level during the active part of the contraction cycle)] during 100 maximal dynamic knee extensions at 90░.s-1. Each contraction cycle comprised of 1 s of active knee extension and 1 s of passive knee flexion. The surface EMG was recorded from the vastus lateralis muscle. Twenty clinically healthy subjects participated in the study, and muscle biopsy samples of the vastus lateralis were obtained from 19 of those subjects. The relationships between muscle morphology and EMG were investigated at three stages of the test: initially, during the fatigue phase (initial 40 contractions), and at the endurance level (the final 50 contractions). Major findings on correlations are that SAR and MNF tended to correlate positively with the proportion of type 1 fibres, and RMS correlated positively with the proportion of type 2 muscle fibres. The muscle fibre areas showed little correlation with the EMG variables under investigation. The results of the present study showed that the three EMG variables of a dynamic endurance test that were investigated (RMS, MNF and SAR were clearly correlated with the proportions of the different fibre types, but only to a small extent with fibre areas. These findings contradict some of the theoretical models of the EMG, especially for parameters in the frequency domain.

  • 78.
    Gerdle, Björn
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Kristiansen, Jesper
    National Research Centre Working Environm, Denmark.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Saltin, Bengt
    University of Copenhagen, Denmark.
    Sogaard, Karen
    University of Southern Denmark, Denmark.
    Sjogaard, Gisela
    University of Southern Denmark, Denmark.
    Algogenic substances and metabolic status in work-related Trapezius Myalgia: a multivariate explorative study2014In: BMC Musculoskeletal Disorders, ISSN 1471-2474, E-ISSN 1471-2474, Vol. 15, no 357Article in journal (Refereed)
    Abstract [en]

    Background: This study compares the levels of algesic substances between subjects with trapezius myalgia (TM) and healthy controls (CON) and explores the multivariate correlation pattern between these substances, pain, and metabolic status together with relative blood flow changes reported in our previous paper (Eur J Appl Physiol 108: 657-669, 2010). Methods: 43 female workers with (TM) and 19 females without (CON) trapezius myalgia were - using microdialysis - compared for differences in interstitial concentrations of interleukin-6 (IL-6), bradykinin (BKN), serotonin (5-HT), lactate dehydrogenas (LDH), substance P, and N-terminal propeptide of procollagen type I (PINP) in the trapezius muscle at rest and during repetitive/stressful work. These data were also used in multivariate analyses together with previously presented data (Eur J Appl Physiol 108: 657-669, 2010): trapezius muscle blood flow, metabolite accumulation, oxygenation, and pain development and sensitivity. Results: Substance P was significantly elevated in TM (p=0.0068). No significant differences were found in the classical algesic substances (p: 0.432-0.926). The multivariate analysis showed that blood flow related variables, interstitial concentrations of metabolic (pyruvate), and algesic (BKN and K+) substances were important for the discrimination of the subjects to one of the two groups (R-2: 0.19-0.31, pless than0.05). Pain intensity was positively associated with levels of 5-HT and K+ and negatively associated with oxygenation indicators and IL-6 in TM (R-2: 0.24, pless than0.05). A negative correlation existed in TM between mechanical pain sensitivity of trapezius and BKN and IL-6 (R-2: 0.26-0.39, pless than0.05). Conclusion: The present study increased understanding alterations in the myalgic muscle. When considering the system-wide aspects, increased concentrations of lactate, pyruvate and K+ and decreased oxygenation characterized TM compared to CON. There are three major possible explanations for this finding: the workers with pain had relatively low severity of myalgia, metabolic alterations preceded detectable alterations in levels of algesics, or peripheral sensitization and other muscle alterations existed in TM. Only SP of the investigated algesic substances was elevated in TM. Several of the algesics were of importance for the levels of pain intensity and mechanical pain sensitivity in TM. These results indicate peripheral contribution to maintenance of central nociceptive and pain mechanisms and may be important to consider when designing treatments.

  • 79.
    Gerdle, Björn
    et al.
    Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Pain and Occupational Centre, Pain and Rehabilitation Centre. Linköping University, Faculty of Health Sciences.
    Larsson, Barbro
    Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Karlsson, Stefan
    Department of Biomedical Engineering and Informatics, University Hospital, Umeå, Sweden.
    Criterion validation of surface EMG variables as fatigue indicators using peak torque: a study of repetitive maximum isokinetic knee extensions2000In: Journal of Electromyography & Kinesiology, ISSN 1050-6411, E-ISSN 1873-5711, Vol. 10, no 4, p. 225-232Article in journal (Refereed)
    Abstract [en]

    A number of studies have been published that have used variables of the electromyogram (EMG) power spectrum during dynamic exercise. Despite these studies there is a shortage of studies of the validity of surface EMG registrations during repetitive dynamic contractions with respect to fatigue. The aim of this study was to investigate if the surface EMG variables mean frequency (MNF [Hz]) and the signal amplitude (RMS [μV]) are valid indicators of muscular fatigue (defined as “any exercise-induced reduction in the capacity to generate force or power output”) during maximum repeated isokinetic knee extensions (i.e. criterion validity using peak torque).

    Twenty-one healthy volunteers performed 100 isokinetic knee extensions at 90° s-1. EMG signals were recorded from the vastus lateralis, the rectus femoris and the vastus medialis of the right thigh by surface electrodes. MNF and RMS of the EMG together with peak torque (PT [Nm]) were determined for each contraction. MNF showed consequently higher correlation coefficients with PT than RMS did. Positive correlations generally existed between MNF and PT. The majority of the subjects had positive correlations between RMS and PT (i.e. decreases both in PT and in RMS).

    In conclusion, at the individual level MNF generally — in contrast to RMS — showed good criterion validity with respect to biomechanical fatigue during dynamic maximum contractions.

  • 80.
    Gerdle, Björn
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Muscle2018In: Fibromyalgia syndrome and widespread pain: from Construction to relevant Recognition / [ed] Winifried Häuser & Serge Perrot, Wolters Kluwer, 2018, p. 215-231Chapter in book (Other academic)
  • 81.
    Gerdle, Björn
    et al.
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Potential Muscle Biomarkers of Chronic Myalgia in Humans - A Systematic Review of Microdialysis Studies2012In: Biomarker / [ed] Tapan Kumar Khan, INTECH, 2012, p. 102-132Chapter in book (Other academic)
    Abstract [en]

    The impact of biomarkers in present day health care system, health management and healthy life is enormous. Clinicians need them for diagnosis, prognosis, effect of therapeutic intervention, and most importantly, for early detection of a disease. Pharmaceutical industries need them for new drug discovery and drug efficiency test. Regulatory authorities need them for testing toxicity and environmental impact. Epidemiologists need them for population screening and risk factor determination. In post genomic era biomarkers would have a huge impact in personalized medicine and personalized health management. This scope of this book is not limited to just a few of the most important aspects of biomarkers but covers wide variety of subjects, from biomarkers cancer to neurodegenerative diseases. Chapters cover variety of aspects, from modern cell based technologies to molecular imaging; from drug discovery to critical care prognosis. A great amount of information is also devoted to bioinformatics and statistics. There is an enormous potential for commercial value of biomarkers. The global diagnostic market accounts for only 1-2% of government healthcare expense, however, it influences on 60-70% decisions in healthcare. My sincere thanks go to all the contributors of this book who took the extra effort beyond their busy schedules. Last, but not least I would like to express my gratitude to the publishing group for their tireless support

  • 82.
    Gerdle, Björn
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Forsberg, Frida
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Ghafouri, Nazdar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Karlsson, Linn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Stensson, Niclas
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Östergötlands Läns Landsting, Heart and Medicine Center, Occupational and Environmental Medicine Center.
    Chronic Widespread Pain: Increased Glutamate and Lactate Concentrations in the Trapezius Muscle and Plasma2014In: The Clinical Journal of Pain, ISSN 0749-8047, E-ISSN 1536-5409, Vol. 30, no 5, p. 409-420Article, review/survey (Refereed)
    Abstract [en]

    BACKGROUND:: Chronic widespread pain (CWP), including fibromyalgia syndrome (FM), is associated with prominent negative consequences. CWP has been associated with alterations in the central processing of nociception. Whereas some researchers consider CWP/FM as a central hyperexcitability pain condition, others suggest that the central alterations are maintained by peripheral nociceptive input. Microdialysis can be used in vivo to study muscle alterations in chronic myalgia. AIM:: The aim of the study was to investigate the plasma and interstitial concentrations of metabolites and algesics in the trapezius muscle of women with CWP and in pain-free women (CON).

    MATERIALS AND METHODS:: Seventeen women with CWP and 24 CON went through a clinical examination and completed a questionnaire; the pressure pain thresholds in the upper and lower extremities were registered. Microdialysis was conducted in the trapezius muscle, and a blood sample was drawn. Muscle blood flow, interstitial muscle concentrations, and plasma concentrations of lactate, pyruvate, glutamate, glucose, and glycerol (not in the plasma) were determined.

    RESULTS:: CWP patients had significantly increased interstitial muscle (P=0.02 to 0.001) and plasma (P=0.026 to 0.017) concentrations of lactate and glutamate. No significant differences existed in blood flow between CWP and CON. The interstitial concentrations-but not the plasma levels-of glutamate and lactate correlated significantly with aspects of pain such as pressure pain thresholds of the trapezius (R=0.22) and tibialis anterior (R=0.18) and the mean pain intensity (R=0.10) in CWP but not in CON.

    CONCLUSIONS:: The present study supports the suggestion that aspects of pain and central alterations in CWP/FM are influenced by peripheral tissue alterations.

  • 83.
    Gerdle, Björn
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Lemming, Dag
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Kristiansen, Jesper
    Cyncron A/S.
    Larsson, Britt
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Peolsson, Michael
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences.
    Rosendal, Lars
    National Research Centre for the Working Environment.
    Biochemical alterations in the trapezius muscle of patients with chronic whiplash associated disorders (WAD): A microdialysis study2008In: European Journal of Pain, ISSN 1090-3801, E-ISSN 1532-2149, Vol. 12, no 1, p. 82-93Article in journal (Refereed)
    Abstract [en]

    The mechanisms behind the development of chronic trapezius myalgia in patients with whiplash associated disorders (WAD) appear to involve both peripheral and central components, but the specific contribution of alterations in muscle is not clear. Female patients with WAD and involvement of trapezius (N = 22) and female controls (N = 20; CON) were studied during an experiment compromised of rest (baseline), 20 min repetitive low-force exercise and 120 min recovery. Their interstitial concentrations of serotonin (5-HT), glutamate, lactate, pyruvate, potassium, interleukin-6 (IL-6), and blood flow were determined in the trapezius muscle using a microdialysis technique. Pressure pain thresholds (PPT) over trapezius and tibialis anterior muscles were also assessed. In WAD, we found signs of generalized hypersensitivity according to PPT. The WAD group had significantly higher interstitial [IL-6] and [5-HT] in the trapezius than the CON. [Pyruvate] was overall significantly lower in WAD, and with lactate it showed another time-pattern throughout the test. In the multivariate regression analysis of pain intensity [5-HT] was the strongest regressor and positively correlated with pain intensity in WAD. In addition, blood flow, [pyruvate], and [potassium] influenced the pain intensity in a complex time dependent way. These findings may indicate that peripheral nociceptive processes are activated in WAD with generalized hypersensitivity for pressure and they are not identical with those reported in chronic work-related trapezius myalgia, which could indicate different pain mechanisms.

  • 84.
    Gerdle, Björn
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Molander, Peter
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Stenberg, Gunilla
    Department of Community Medicine and Rehabilitation, Physiotherapy, Umeå University, Umeå, Sweden.
    Stålnacke, Britt-Marie
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Enthoven, Paul
    Linköping University, Department of Medical and Health Sciences, Division of Physiotherapy. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in West Östergötland, Research & Development Unit in Local Health Care. 5 Department of Community Medicine and Rehabilitation, Rehabilitation Medicine, Umeå University, Umeå, Sweden.
    Weak outcome predictors of multimodal rehabilitation at one-year follow-up in patients with chronic pain-a practice based evidence study from two SQRP centres.2016In: BMC Musculoskeletal Disorders, ISSN 1471-2474, E-ISSN 1471-2474, Vol. 17, no 1, article id 490Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: For patients with chronic pain, the heterogeneity of clinical presentations makes it difficult to identify patients who would benefit from multimodal rehabilitation programs (MMRP). Yet, there is limited knowledge regarding the predictors of MMRP's outcomes. This study identifies predictors of outcome of MMRPs at a 12-month follow-up (FU-12) based on data from the Swedish Quality Registry for Pain Rehabilitation (SQRP).

    METHODS: Patients with chronic pain from two clinical departments in Sweden completed the SQRP questionnaires-background, pain characteristics, psychological symptoms, function, activity/participation, health and quality of life-on three occasions: 1) during their first visit; 2) immediately after the completion of their MMRP; and 3) 12 months after completing the MMRP (n = 227). During the FU-12, the patients also retrospectively reported their global impressions of any changes in their perception of pain and their ability to handle their life situation in general.

    RESULTS: Significant improvements were found for pain, psychological symptoms, activity/participation, health, and quality of life aspects with low/medium strong effects. A general pattern was observed from the analyses of the changes from baseline to FU-12; the largest improvements in outcomes were significantly associated with poor situations according to their respective baseline scores. Although significant regressors of the investigated outcomes were found, the significant predictors were weak and explained a minor part of the variation in outcomes (15-25%). At the FU-12, 53.6% of the patients reported that their pain had decreased and 80.1% reported that their life situation in general had improved. These improvements were associated with high education, low pain intensity, high health level, and work importance (only pain perception). The explained variations were low (9-11%).

    CONCLUSIONS: Representing patients in real-world clinical settings, this study confirmed systematic reviews that outcomes of MMRP are associated with broad positive effects. A mix of background and baseline variables influenced the outcomes investigated, but the explained variations in outcomes were low. There is still a need to develop standardized and relatively simple outcomes that can be used to evaluate MMRP in trials, in clinical evaluations at group level, and for individual patients.

  • 85.
    Gerdle, Björn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Sandberg, Margaretha
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Akuta och kroniska nociceptiva smärtor. Den biopsykosociala helhetssynen och aspekter på de neurobiologiska mekanismerna2006In: Rehabiliteringsmedicin - Teori och praktik / [ed] Jörgen Borg, Lund: Studenlitteratur , 2006, 1, p. 78-89Chapter in book (Other academic)
    Abstract [sv]

           Kapitel om rehabiliteringsmedicinens utveckling och nuvarande plats i sjukvården samt begrepp och metodik inleder boken. I två delar ges därefter rehabiliteringsmedicinska aspekter på de dominerande sjukdomsgrupperna - komplexa smärttillstånd respektive skador och sjukdomar i nervsystemet. Som avslutning beskrivs bland annat  stressrelaterade tillstånd. Läroboken är avsedd för grundutbildning av läkare, arbetsterapeuter och sjukgymnaster, logopeder samt för läkare under AT-tjänstgöring. Den är också lämplig som introduktion i specialistutbildningen i rehabiliteringsmedicin, geriatrik, neurologi och smärtlindring. Vidareutbildningar av olika vårdyrkesgrupper kan ha nytta av boken och den kan också användas som referenslitteratur av yrkesverksamma med intresse för rehabiliteringsmedicin

  • 86.
    Gerdle, Björn
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Soderberg, Kristina
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine .
    Salvador Puigvert, Laia
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences.
    Rosendal, Lars
    TrialConsult, Gentofte, Denmark.
    Larsson, Britt
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    INCREASED INTERSTITIAL CONCENTRATIONS OF PYRUVATE AND LACTATE IN THE TRAPEZIUS MUSCLE OF PATIENTS WITH FIBROMYALGIA: A MICRODIALYSIS STUDY2010In: Journal of Rehabilitation Medicine, ISSN 1650-1977, E-ISSN 1651-2081, Vol. 42, no 7, p. 679-687Article in journal (Refereed)
    Abstract [en]

    Objective: The aim of this study was to compare the interstitial concentrations of pyruvate, lactate and glutamate in the trapezius muscle between patients with fibromyalgia syndrome and healthy controls. Design: Comparative cross-sectional study. Subjects: Patients with fibromyalgia (n=19) and healthy controls (n=19); all women. Methods: Subjects answered a questionnaire about different aspects of pain. Pressure pain thresholds over the trapezius and tibialis anterior muscles were determined. The interstitial concentrations of pyruvate, lactate and glutamate were determined in the resting trapezius muscle by the microdialysis technique, with samples collected every hour for 5 consecutive hours. Pain intensity was also rated. Results: Significantly higher interstitial concentrations of pyruvate and lactate were found in patients with fibromyalgia syndrome. The multivariate regression analyses of group membership and pressure pain thresholds of the trapezius confirmed the importance of pyruvate and lactate. Conclusion: Different mechanisms that may increase pyruvate and lactate in patients with fibromyalgia syndrome are discussed. Improved understanding of peripheral muscle alterations in patients with fibromyalgia syndrome could lead to mechanism-based rehabilitation.

  • 87.
    Gerdle, Björn
    et al.
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Stålnacke, Britt-Marie
    Umeå universitet / Norrlands universitetssjukhus, Umeå.
    Borg, Kristian
    Karolinska institutet / Danderyds sjukhus, Stockholm.
    Ruding, Karin
    Akademiska sjukhuset, Uppsala.
    Brodda Jansen, Gunilla
    Karolinska institutet / Danderyds sjukhus, Stockholm.
    Rivano Fischer, Marcello
    Lunds universitet / Skånes universitetssjukhus.
    Utvärdering av rehabiliteringsgarantin kräver bättre vetenskapligt underlag: [Evaluation of the rehabilitation guarantee requires better scientific support]2013In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 110, no 9-10, p. 499-Article in journal (Refereed)
    Abstract [sv]

    Inspektionen för socialförsäkringen har utvärderat ­rehabiliteringsgarantin. Rapporten uppvisar stora brister, vilket bekräftas av en granskning av den del som rör multimodal rehabilitering vid långvariga smärtor.

  • 88.
    Gerdle, Björn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Sörensen, Jan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Radiofrekvensbehandling2006In: Metoder för behandling av långvarig smärta: En systematisk litteraturöversikt / [ed] Statens beredning för medicinsk utvärdering, Stockholm: Statens beredning för medicinsk utvärdering (SBU) , 2006, p. 339-343Chapter in book (Other academic)
    Abstract [sv]

    I denna rapport sammanfattas det vetenskapliga underlaget för behandling av långvariga smärttillstånd. Smärta vid cancer innefattas inte. Smärtlindrande effekter, liksom biverkningar och andra negativa konsekvenser av behandling berörs samt hälsoekonomiska aspekter.

  • 89.
    Gerdle, Björn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Östlund, Nils
    Department of Biomedical Engineering and Informatics University Hospital, Umeå.
    Grönlund, Christer
    Department of Biomedical Engineering and Informatics University Hospital, Umeå.
    Roeleveld, Karin
    Human Movement Sciences Programme Norwegian University of Science and Technology, Trondheim.
    Karlsson, J. Stefan
    Department of Biomedical Engineering and Informatics University University Hospital, Umeå.
    Firing rate and conduction velocity of single motor units in the trapezius muscle in fibromyalgia patients and healthy controls2008In: Journal of Electromyography & Kinesiology, ISSN 1050-6411, E-ISSN 1873-5711, Vol. 18, no 5, p. 707-716Article in journal (Refereed)
    Abstract [en]

    Fibromyalgia is a common chronic pain condition in the population (2-4%), which often is associated with prominent negative consequences with respect to participation in daily activities. There are several reports in the literature concerning the effects of acute experimental pain on motor control. However, a more heterogeneous picture exists in the literature with respect to whether chronic pain conditions affect motor control. This study compares firing rate and conduction velocity (CV) of single motor units (MUs) in the trapezius muscle of fibromyalgia patients (FM) and healthy controls (CON). Multi-channel surface electromyography was used to estimate both MU firing rate and CV because this technique allows simultaneous estimation of both these variables and the measurements are easy and non-invasive. In this study, 29 FM and 30 CON subjects participated and performed isometric shoulder elevations using weights up to 4 kg. No significant differences in the firing rate of MUs in the trapezius muscle were found between the FM and CON groups (95% confidence interval was -1.9 and 1.3 pulses per second). There were no significant differences in CV between the groups at 1 and 2 kg load. However, the FM group had significantly higher CV in contractions without external load (p = 0.004). We were unable to confirm the pain-adaptation model since no differences in firing rate between the two groups were found. CV was significantly higher in FM than in healthy controls, this might be due to alterations in histopathology and microcirculation. © 2007 Elsevier Ltd. All rights reserved.

  • 90.
    Ghafouri, Bijar
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Larsson, Britt
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Sjörs, Anna
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Leandersson, Per
    Linköping University, Department of Clinical and Experimental Medicine, Occupational and Environmental Medicine. Östergötlands Läns Landsting, Heart and Medicine Centre, Occupational and Environmental Medicine Centre. Linköping University, Faculty of Health Sciences.
    Gerdle, Björn
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    Interstitial concentration of serotonin is increased in myalgic human trapezius muscle during rest, repetitive work and mental stress - an in vivo microdialysis study2010In: Scandinavian Journal of Clinical and Laboratory Investigation, ISSN 0036-5513, E-ISSN 1502-7686, Vol. 70, no 7, p. 478-486Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES: The pathophysiology of trapezius myalgia is not fully elucidated. Serotonin (5-HT) is involved in modulation of nociception and hyperalgesia. Our aim was to compare the interstitial 5-HT levels of the trapezius muscle in women with chronic trapezius myalgia and in pain-free controls.

    MATERIALS AND METHODS: Microdialysate of the trapezius muscle collected every 20 minutes during rest, work (100 min) and stress (20 min) was used to study the dynamics of 5-HT in women with chronic trapezius myalgia (MYA; n=18) and in pain-free controls (CON; n=30).

    RESULTS: MYA had higher levels of 5-HT than CON at baseline, during repetitive work, during mental stress and during recovery. There were no significant time effects on 5-HT levels.

    CONCLUSION: 5-HT has the potential of a biomarker of chronic myalgia. Elevated levels of 5-HT may be involved in maintenance of habitual chronic pain and might contribute to increased pain during exercise by facilitating the effect of released algesic substances linked to such muscle demands.

  • 91.
    Ghafouri, Nazdar
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Umeå University, Umeå, Sweden.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Östergötlands Läns Landsting, Heart and Medicine Center, Occupational and Environmental Medicine Center.
    Fowler, Christopher J.
    Umeå University, Sweden.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Turkina, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Karlsson, Linn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Effects of Two Different Specific Neck Exercise Interventions on Palmitoylethanolamide and Stearoylethanolamide Concentrations in the Interstitium of the Trapezius Muscle in Women with Chronic Neck Shoulder Pain2014In: Pain medicine (Malden, Mass.), ISSN 1526-2375, E-ISSN 1526-4637, Vol. 15, no 8, p. 1379-1389Article in journal (Refereed)
    Abstract [en]

    Purpose. Chronic neck/shoulder pain (CNSP) is one of the most common pain conditions. The understanding of mechanisms, including the peripheral balance between nociceptive and antinociceptive processes, is incomplete. N-acylethanolamines (NAEs) are a class of endogenous compounds that regulate inflammation and pain. The aim of this study was to investigate the levels of two NAEs: the peroxisome proliferator-activated receptor type-a ligand palmitoylethanolamide (PEA) and stearoylethanolamide (SEA) in the muscle interstitium of the trapezius muscle in women with CNSP randomized to two different neck specific training programs and in a healthy pain-free control group (CON). Materials and Methods. Fifty-seven women with CNSP were randomized to strength + stretch or stretch alone exercise programs. Twenty-nine subjects underwent microdialysis procedure before and after 4-6 months of exercise. Twenty-four CON subjects underwent microdialysis procedure before and after 4-6 months without any intervention in between. Microdialysate samples were collected from the trapezius muscle and analyzed by mass spectrometry for PEA and SEA levels. Results. PEA and SEA levels were significantly higher in CNSP patients compared with CON. PEA was significantly higher in CNSP than in CON after both training programs. SEA was significantly higher in CNSP than in CON after stretch alone but not after strength + stretch training. A significant positive correlation was found between changes in pain intensity and in SEA levels in the strength + stretch group, but not in the stretch alone group. Conclusion. Our results indicate that exercise interventions differentially affect the levels of the bioactive lipids PEA and SEA in the interstitium of the trapezius muscle in women with CNSP.

  • 92.
    Ghafouri, Nazdar
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center. Östergötlands Läns Landsting, Heart and Medicine Center, Occupational and Environmental Medicine Center.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Stensson, Niclas
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    Fowler, Christopher J.
    Umeå University, Sweden .
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Palmitoylethanolamide and stearoylethanolamide levels in the interstitium of the trapezius muscle of women with chronic widespread pain and chronic neck-shoulder pain correlate with pain intensity and sensitivity2013In: Pain, ISSN 0304-3959, E-ISSN 1872-6623, Vol. 154, no 9, p. 1649-1658Article in journal (Refereed)
    Abstract [en]

    Chronic widespread pain (CWP) is a complex condition characterized by central hyperexcitability and altered descending control of nociception. However, nociceptive input from deep tissues is suggested to be an important drive. N-Acylethanolamines (NAEs) are endogenous lipid mediators involved in regulation of inflammation and pain. Previously we have reported elevated levels of the 2 NAEs, the peroxisome proliferator-activated receptor type-alpha ligand N-palmitoylethanolamine (PEA) and N-stearoylethanolamine (SEA) in chronic neck/shoulder pain (CNSP). In the present study, the levels of PEA and SEA in women with CWP (n = 18), CNSP (n = 34) and healthy controls (CON, n = 24) were investigated. All subjects went through clinical examination, pressure pain threshold measurements and induction of experimental pain in the tibialis anterior muscle. Microdialysis dialysate of the trapezius was collected before and after subjects performed a repetitive low-force exercise and analyzed by mass spectrometry. The levels of PEA and SEA in CNSP were significantly higher post exercise compared with CWP, and both pre and post exercise compared with CON. Levels of both NAEs decreased significantly pre to post exercise in CWP. Intercorrelations existed between aspects of pain intensity and sensitivity and the level of the 2 NAEs in CWP and CNSP. This is the first study demonstrating that CNSP and CWP differ in levels of NAEs in response to a low-force exercise which induces pain. Increases in pain intensity as a consequence of low-force exercise were associated with low levels of PEA and SEA in CNSP and CWP. These results indicate that PEA and SEA have antinociceptive roles in humans.

  • 93.
    Ghafouri, Nazdar
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Ghafouri, Bijar
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre. Östergötlands Läns Landsting, Heart and Medicine Centre, Occupational and Environmental Medicine Centre.
    Larsson, Britt
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    Turkina, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Karlsson, Linn
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences.
    Fowler, Christopher J.
    Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    Gerdle, Björn
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Pain and Rehabilitation Centre.
    High Levels of N-Palmitoylethanolamide and N-Stearoylethanolamide in Microdialysate Samples from Myalgic Trapezius Muscle in Women2011In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 6, no 11Article in journal (Refereed)
    Abstract [en]

    Background: N-acylethanolamines (NAEs) are endogenous compounds that regulate inflammation and pain. These include the cannabinoid ligand anandamide (AEA) and the peroxisome proliferator-activated receptor-a ligand palmitoylethanolamide (PEA). Little is known as to the levels of NAEs in pain states in human, particularly in the skeletal muscle. The aim of this study was to investigate the levels of these lipid mediators in muscle dialysate from women with chronic neck-/shoulder pain compared to healthy controls. Methods: Eleven women with chronic neck-/shoulder pain and eleven healthy women participated in this study. All participants went through microdialysis procedures in the trapezius muscle. Muscle dialysate samples were collected during four hours and analysed by nano liquid chromatography tandem mass spectrometry (nLC-MS/MS). Results: We were able to detect AEA, PEA, N-stearoylethanolamine (SEA) and 2-arachidonoylglycerol (2-AG) in a single chromatographic run. Of the NAEs studied, PEA and SEA were clearly detectable in the muscle microdialysate samples. The muscle dialysate levels of PEA and SEA were significantly higher in myalgic subjects compared to healthy controls. Conclusion: This study demonstrates that microdialysis in combination with mass spectrometry can be used for analysing NAEs in human muscle tissue regularly over time. Furthermore the significant group differences in the concentration of PEA and SEA in this study might fill an important gap in our knowledge of mechanisms in chronic myalgia in humans. In the long run this expanded understanding of nociceptive and anitinociceptive processes in the muscle may provide a base for ameliorating treatment and rehabilitation of pain.

  • 94. Graven-Nilsen, T
    et al.
    Aspegren Kendall, Sally
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine/Pain Clinic. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Henriksson, Karl-Gösta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine/Pain Clinic. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Bengtsson, M
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Anaesthesiology. Östergötlands Läns Landsting, MKC - Medicin och kirurgicentrum, Anestesi.
    Sörensen, Jan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Anaesthesiology. Östergötlands Läns Landsting, MKC - Medicin och kirurgicentrum, Anestesi.
    Johnson, A
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Anaesthesiology. Östergötlands Läns Landsting, MKC - Medicin och kirurgicentrum, Anestesi.
    Gerdle, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine/Pain Clinic. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Arendt-Nielsen, L
    Ketamine reduces muscle pain, temporal summation, and referred pain in fibromyalgia patients2000In: Pain, ISSN 0304-3959, E-ISSN 1872-6623, Vol. 85, no 3, p. 483-491Article in journal (Refereed)
    Abstract [en]

    Central mechanisms related to referred muscle pain and temporal summation of muscular nociceptive activity are facilitated in fibromyalgia syndrome (FMS) patients. The present study assessed the effects of an NMDA-antagonist (ketamine) on these central mechanisms. FMS patients received either i.v. placebo or ketamine (0.3 mg/kg, Ketalar(«)) given over 30 min on two separate occasions. Habitual pain intensity was assessed on a visual analogue scale (VAS). Initially, 29 FMS patients received ketamine or isotonic saline to determine which patients were ketamine responders (>50% decrease in pain intensity at rest by active drug on two consecutive VAS assessments). Fifteen out of 17 ketamine-responders were included in the second part of the study. Before and after ketamine or placebo, experimental local and referred pain was induced by intramuscular (i.m.) infusion of hypertonic saline (0.7 ml, 5%) into the tibialis anterior (TA) muscle. The saline-induced pain intensity was assessed on an electronic VAS, and the distribution of pain drawn by the subject. In addition, the pain threshold (PT) to i.m. electrical stimulation was determined for single stimulus and five repeated (2 Hz, temporal summation) stimuli. The pressure PT of the TA muscle was determined, and the pressure PT and pressure pain tolerance threshold were determined at three bilaterally located tenderpoints (knee, epicondyle, and mid upper trapezius). VAS scores of pain at rest were progressively reduced during ketamine infusion compared with placebo infusion. Pain intensity (area under the VAS curve) to the post-drug infusion of hypertonic saline was reduced by ketamine (-18.4▒0.3% of pre-drug VAS area) compared with placebo (29.9▒18.8%, P<0.02). Local and referred pain areas were reduced by ketamine (-12.0▒14.6% of pre-drug pain areas) compared with placebo (126.3▒83.2%, P<0.03). Ketamine had no significant effect on the PT to single i.m. electrical stimulation. However, the span between the PT to single and repeated i.m. stimuli was significantly decreased by the ketamine (-42.3▒15.0% of pre-drug PT) compared with placebo (50.5▒49.2%, P<0.03) indicating a predominant effect on temporal summation. Mean pressure pain tolerance from the three paired tenderpoints was increased by ketamine (16.6▒6.2% of pre-drug thresholds) compared with placebo (-2.3▒4.9%, P<0.009). The pressure PT at the TA muscle was increased after ketamine (42.4▒9.2% of pre-drug PT) compared with placebo (7.0▒6.6%, P<0.011). The present study showed that mechanisms involved in referred pain, temporal summation, muscular hyperalgesia, and muscle pain at rest were attenuated by the NMDA-antagonist in FMS patients. It suggested a link between central hyperexcitability and the mechanisms for facilitated referred pain and temporal summation in a sub-group of the fibromyalgia syndrome patients. Whether this is specific for FMS patients or a general phenomena in painful musculoskeletal disorders is not known. Copyright (C) 2000 International Association for the Study of Pain. Published by Elsevier Science B.V.

  • 95.
    Grimby-Ekman, Anna
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. University of Gothenburg, Sweden.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Bjork, Jonas
    Lund University, Sweden.
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Comorbidities, intensity, frequency and duration of pain, daily functioning and health care seeking in local, regional, and widespread pain-a descriptive population-based survey (SwePain)2015In: BMC Musculoskeletal Disorders, ISSN 1471-2474, E-ISSN 1471-2474, Vol. 16, no 165Article in journal (Refereed)
    Abstract [en]

    Background: The clinical knowledge of factors related to the spread of pain on the body has increased and understanding these factors is essential for effective pain treatment. This population-based study examines local (LP), regional (RP), and widespread pain (WSP) on the body regarding comorbidities, pain aspects, and impact of pain and elucidates how the spread of pain varies over time. Material and methods: A postal questionnaire that addressed pain aspects (intensity, frequency, duration and anatomical spreading on a body manikin), comorbidities and implications of pain (i.e., work situation, physical activity, consumption of health care and experience of hospitality and treatment of health care) was sent to 9000 adults living in southeastern Sweden. Of these, 4774 (53 %) completed and returned the questionnaire. After 9 weeks, a follow-up questionnaire was sent to the 2983 participants who reported pain in the first questionnaire (i.e. 62 % of 4774 subjects). Of these, 1940 completed and returned the questionnaire (i.e. 65 % of 2983 subjects). The follow-up questionnaire included the same items as the first questionnaire. Results: This study found differences in intensity, frequency and duration of pain, comorbidities, aspects of daily functioning and health care seeking in three pain categories based on spreading of pain: LP, RP and WSP. Compared to the participants with RP and LP, the participants with WSP had lower education and worse overall health, including more frequent heart disease and hypertension. In addition, participants with WSP had more intense, frequent, and long-standing pain, required more medical consultations, and experienced more impact on work. The participants with RP constituted an intermediate group regarding frequency and intensity of pain, and impact on work. The participants with LP were the least affected group regarding these factors. A substantial transition to RP had occurred by the 9-week follow-up. Conclusions: This study shows an association between increased spread of pain and prevalence of heart disease, hypertension, more severe pain characteristics (i.e., intensity, frequency and duration), problems with common daily activities and increased health care seeking. The WSP group was the most affected group and the LP group was the least affected group. Regarding these factors, RP was an obvious intermediate group. The transitions between the pain categories warrant research that broadly investigates factors that increase and decrease pain.

  • 96.
    Grimby-Ekman, Anna
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Health Metrics, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden Occupational and Environmental Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden .
    Ghafouri, Bijar
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Sandén, H
    Occupational and Environmental Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden..
    Larsson, Britt
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Different DHEA-S Levels and Response Patterns in Individuals with Chronic Neck Pain, Compared with a Pain Free Group-a Pilot Study.2017In: Pain medicine (Malden, Mass.), ISSN 1526-2375, E-ISSN 1526-4637, Vol. 18, no 5, p. 846-855Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: To test, in this pilot study, whether DHEA-S (Dehydroepiandrosterone, sulfated form) plasma levels are lower among persons with chronic neck pain, compared to control persons, and to investigate the DHEA-S response after a physical exercise.

    SUBJECTS: Included were 12 persons with chronic neck pain and eight controls without present pain, all 18 and 65 years of age. Exclusion criteria for both groups were articular diseases or tendinosis, fibromyalgia, systemic inflammatory and neuromuscular diseases, pain conditions due to trauma, or severe psychiatric diseases.

    DESIGN AND METHODS: The participants arm-cycled on an ergometer for 30 minutes. Blood samples were taken before, 60 minutes, and 150 minutes after this standardized physical exercise.

    RESULTS: The estimated plasma DHEA-S levels at baseline were 2.0 µmol/L (95% confidence interval [CI] 1.00; 4.01) in the pain group and 4.1 µmol/L (95% CI2.0; 8.6) in the control group, adjusted for sex, age, body mass index (BMI), and Shirom-Melamed Burnout Questionnaire (SMBQ), with a ratio of 0.48 (P = 0.094).The total DHEA-S (AUCG) in the pain group were 183 min*µmol/L lower than in the control group (P = 0.068). For the response to the exercise (AUCI), the difference between the pain group and the control group was 148 min*µmol/L (P = 0.011).

    CONCLUSIONS: In this pilot study, the plasma DHEA-S levels appeared to be lower among the persons with chronic neck pain, compared with the control group. It was indicated that DHEA-S decreased during the physical exercise in the control group, and either increased or was unaffected in the chronic pain group.

  • 97.
    Grip, Helen
    et al.
    Universitetssjukhuset Umeå.
    Sundelin, Gunnevi
    Umeå universitet.
    Gerdle, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Karlsson, Stefan
    Universitetssjukhuset Umeå.
    Variations in the axis of motion during head repositioning - A comparison of subjects with whiplash-associated disorders or non-specific neck pain and healthy controls2007In: Clinical Biomechanics, ISSN 0268-0033, E-ISSN 1879-1271, Vol. 22, no 8, p. 865-873Article in journal (Refereed)
    Abstract [en]

    Background: The ability to reproduce head position can be affected in patients after a neck injury. The repositioning error is commonly used as a measure of proprioception, but variations in the movement might provide additional information. Methods: The axis of motion and target performance were analyzed during a head repositioning task (flexion, extension and side rotations) for 24 control subjects, 22 subjects with whiplash-associated disorders and 21 with non-specific neck pain. Questionnaires regarding pain intensity and fear avoidance were collected. Head position and axis of motion parameters were calculated using a helical axis model with a moving window of 4°. Findings: During flexion the whiplash group had a larger constant repositioning error than the control group (-1.8(2.9)° vs. 0.1(2.4)°, P = 0.04). The axis was more inferior in both neck pain groups (12.0(1.6) cm vs. 14.5(2.0) cm, P < 0.05) indicating movement at a lower level in the spine. Including pain intensity from shoulder and neck region as covariates showed an effect on the axis position (P = 0.03 and 0.04). During axial rotation to the left there was more variation in axis direction for neckpain groups as compared with controls (4.0(1.7)° and 3.7(2.4)° vs. 2.3(1.9)°, P = 0.01 and 0.05). No significant difference in fear avoidance was found between the two neck pain groups. Interpretation: Measuring variation in the axis of motion together with target performance gives objective measures on proprioceptive ability that are difficult to quantify by visual inspection. Repositioning errors were in general small, suggesting it is not sufficient as a single measurement variable in a clinical situation, but should be measured in combination with other tests, such as range of motion.

  • 98. Grip, Helena
    et al.
    Sundelin, Gunnevi
    Gerdle, Björn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine . Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Karlsson, J. Stefan
    Cervical helical axis characteristics and its center of rotation during active head and upper arm movements-comparisons of whiplash-associated disorders, non-specific neck pain and asymptomatic individuals2008In: Journal of Biomechanics, ISSN 0021-9290, E-ISSN 1873-2380, Vol. 41, no 13, p. 2799-2805Article in journal (Refereed)
    Abstract [en]

    The helical axis model can be used to describe translation and rotation of spine segments. The aim of this study was to investigate the cervical helical axis and its center of rotation during fast head movements (side rotation and flexion/extension) and ball catching in patients with non-specific neck pain or pain due to whiplash injury as compared with matched controls. The aim was also to investigate correlations with neck pain intensity. A finite helical axis model with a time-varying window was used. The intersection point of the axis during different movement conditions was calculated. A repeated-measures ANOVA model was used to investigate the cervical helical axis and its rotation center for consecutive levels of 15° during head movement. Irregularities in axis movement were derived using a zero-crossing approach. In addition, head, arm and upper body range of motion and velocity were observed. A general increase of axis irregularity that correlated to pain intensity was observed in the whiplash group. The rotation center was superiorly displaced in the non-specific neck pain group during side rotation, with the same tendency for the whiplash group. During ball catching, an anterior displacement (and a tendency to an inferior displacement) of the center of rotation and slower and more restricted upper body movements implied a changed movement strategy in neck pain patients, possibly as an attempt to stabilize the cervical spine during head movement. © 2008 Elsevier Ltd. All rights reserved.

  • 99.
    Grip, Helena
    et al.
    Department of Biomedical Engineering and Informatics, University Hospital, Umeå, Sweden.
    Öhberg, Fredrik
    Department of Biomedical Engineering and Informatics, University Hospital, Umeå, Sweden.
    Wiklund, Urban
    Department of Biomedical Engineering and Informatics, University Hospital, Umeå, Sweden.
    Sterner, Ylva
    Community Medicine and Rehabilitation, University Hospital, Umeå, Sweden.
    Karlsson, J. Stefan
    Department of Biomedical Engineering and Informatics, University Hospital, Umeå, Sweden.
    Gerdle, Björn
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Classification of Neck Movement Patterns Related to Whiplash-Associated Disorders Using Neural Networks2003In: IEEE transactions on information technology in biomedicine, ISSN 1089-7771, E-ISSN 1558-0032, Vol. 7, no 4, p. 412-418Article in journal (Refereed)
    Abstract [en]

    This paper presents a new method for classification of neck movement patterns related to Whiplash-associated disorders (WAD) using a resilient backpropagation neural network (BPNN). WAD are a common diagnosis after neck trauma, typically caused by rear-end car accidents. Since physical injuries seldom are found with present imaging techniques, the diagnosis can be difficult to make. The active range of the neck is often visually inspected in patients with neck pain, but this is a subjective measure, and a more objective decision support system, that gives a reliable and more detailed analysis of neck movement pattern, is needed. The objective of this study was to evaluate the predictive ability of a BPNN, using neck movement variables as input. Three-dimensional (3-D) neck movement data from 59 subjects with WAD and 56 control subjects were collected with a ProReflex system. Rotation angle and angle velocity were calculated using the instantaneous helical axis method and motion variables were extracted. A principal component analysis was performed in order to reduce data and improve the BPNN performance. BPNNs with six hidden nodes had a predictivity of 0.89, a sensitivity of 0.90 and a specificity of 0.88, which are very promising results. This shows that neck movement analysis combined with a neural network could build the basis of a decision support system for classifying suspected WAD, even though further evaluation of the method is needed.

  • 100.
    Grundström, Hanna
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, Department of Gynaecology and Obstetrics in Norrköping.
    Gerdle, Björn
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Pain and Rehabilitation Center.
    Alehagen, Siw
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Medicine and Health Sciences.
    Berterö, Carina
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Medicine and Health Sciences.
    Arendt-Nielsen, Lars
    Center for Sensory‐Motor Interactions, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark.
    Kjölhede, Preben
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, Department of Gynaecology and Obstetrics in Linköping.
    Reduced pain thresholds and signs of sensitization in women with persistent pelvic pain and suspected endometriosis2019In: Acta Obstetricia et Gynecologica Scandinavica, ISSN 0001-6349, E-ISSN 1600-0412, Vol. 98, no 3, p. 327-336Article in journal (Refereed)
    Abstract [en]

    INTRODUCTION: Endometriosis is a gynecological disorder that may cause considerable pelvic pain in women of fertile age. Determining pain mechanisms is necessary in order to optimize the treatment of the disease. The objective of the study was to evaluate pain thresholds in women with persistent pelvic pain with and without confirmed endometriosis, and healthy, unaffected controls, and analyze how pain thresholds in these cohorts related to duration of pelvic pain, quality of life, and symptoms of anxiety and depression.

    MATERIAL AND METHODS: Pain thresholds for heat, cold and pressure were assessed with quantitative sensory testing on six locations on a reference group of 55 healthy women and on 37 women with persistent pelvic pain who had been admitted for diagnostic laparoscopy on the suspicion of endometriosis. Validated instruments were applied to assess quality of life and symptoms of anxiety and depression. Data were analyzed by means of uni- and multivariate analysis of variance and Spearman's rank-order correlation.

    RESULTS: The women with persistent pelvic pain had significantly lower pain thresholds compared with the reference women. In the women with pain, no differences were observed in pain thresholds between women with (n = 13) and women without (n = 24) biopsy-proven endometriosis. The duration of pelvic pain correlated significantly positively with reduced pain thresholds, ie, the longer the duration, the more sensitization. In the persistent pelvic pain group, pain thresholds for heat correlated significantly with the Short Form Health Survey 36 dimension of bodily pain, and thresholds for cold correlated with Short Form Health Survey 36 bodily pain and with symptoms of depression.

    CONCLUSIONS: Our results showed widespread alterations in pain thresholds in women with persistent pelvic pain that are indicative of central sensitization and a time-dependent correlation. Women with pelvic pain and suspicion of endometriosis should probably be treated more thoroughly to prevent or at least minimize the concomitant development of central sensitization.

    The full text will be freely available from 2019-11-25 12:48
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