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Chronic Fatigue Syndrome: HELP
Articles by Kelly Ickmans
Based on 19 articles published since 2010
(Why 19 articles?)
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Between 2010 and 2020, K. Ickmans wrote the following 19 articles about Fatigue Syndrome, Chronic.
 
+ Citations + Abstracts
1 Editorial Postural orthostatic tachycardia syndrome as a clinically important subgroup of chronic fatigue syndrome: further evidence for central nervous system dysfunctioning. 2013

Nijs, J / Ickmans, K. · ·J Intern Med · Pubmed #23331489.

ABSTRACT: -- No abstract --

2 Review Altered immune response to exercise in patients with chronic fatigue syndrome/myalgic encephalomyelitis: a systematic literature review. 2014

Nijs, Jo / Nees, Andrea / Paul, Lorna / De Kooning, Margot / Ickmans, Kelly / Meeus, Mira / Van Oosterwijck, Jessica. · ·Exerc Immunol Rev · Pubmed #24974723.

ABSTRACT: An increasing number of studies have examined how the immune system of patients with Chronic Fatigue Syndrome (CFS), or myalgic encephalomyelitis, responds to exercise. The objective of the present study was to systematically review the scientific literature addressing exercise-induced immunological changes in CFS patients compared to healthy control subjects. A systematic literature search was conducted in the PubMed and Web of science databases using different keyword combinations. We included 23 case control studies that examined whether CFS patients, compared to healthy sedentary controls, have a different immune response to exercise. The included articles were evaluated on their methodological quality. Compared to the normal response of the immune system to exercise as seen in healthy subjects, patients with CFS have a more pronounced response in the complement system (i.e. C4a split product levels), oxidative stress system (i.e. enhanced oxidative stress combined with a delayed and reduced anti-oxidant response), and an alteration in the immune cells' gene expression profile (increases in post-exercise interleukin-10 and toll-like receptor 4 gene expression), but not in circulating pro- or anti-inflammatory cytokines. Many of these immune changes relate to post-exertional malaise in CFS, a major characteristic of the illness. The literature review provides level B evidence for an altered immune response to exercise in patients with CFS.

3 Review Fear of movement and avoidance behaviour toward physical activity in chronic-fatigue syndrome and fibromyalgia: state of the art and implications for clinical practice. 2013

Nijs, Jo / Roussel, Nathalie / Van Oosterwijck, Jessica / De Kooning, Margot / Ickmans, Kelly / Struyf, Filip / Meeus, Mira / Lundberg, Mari. ·Pain in Motion research group, Department of Human Physiology and Rehabilitation Sciences, Faculty of Physical Education and Physiotherapy, Vrije Universiteit Brussel, Building L-Mfys, Pleinlaan 2, 1050 Brussels, Belgium. Jo.Nijs@vub.ac.be ·Clin Rheumatol · Pubmed #23639990.

ABSTRACT: Severe exacerbation of symptoms following physical activity is characteristic for chronic-fatigue syndrome (CFS) and fibromyalgia (FM). These exacerbations make it understandable for people with CFS and FM to develop fear of performing body movement or physical activity and consequently avoidance behaviour toward physical activity. The aims of this article were to review what measures are available for measuring fear of movement and avoidance behaviour, the prevalence fear of movement and avoidance behaviour toward physical activity and the therapeutic options with fear of movement and avoidance behaviour toward physical activity in patients with CFS and FM. The review revealed that fear of movement and avoidance behaviour toward physical activity is highly prevalent in both the CFS and FM population, and it is related to various clinical characteristics of CFS and FM, including symptom severity and self-reported quality of life and disability. It appears to be crucial for treatment (success) to identify CFS and FM patients displaying fear of movement and avoidance behaviour toward physical activity. Individually tailored cognitive behavioural therapy plus exercise training, depending on the patient's classification as avoiding or persisting, appears to be the most promising strategy for treating fear of movement and avoidance behaviour toward physical activity in patients with CFS and FM.

4 Review How to exercise people with chronic fatigue syndrome: evidence-based practice guidelines. 2012

Van Cauwenbergh, Deborah / De Kooning, Margot / Ickmans, Kelly / Nijs, Jo. ·Chronic Pain and Chronic Fatigue Research Group (CHROPIVER), Department of Human Physiology, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Belgium. jo.nijs@vub.ac.be ·Eur J Clin Invest · Pubmed #22725992.

ABSTRACT: BACKGROUND: Despite the large number of studies emphasizing the effectiveness of graded exercise therapy (GET) and cognitive behavioural therapy (CBT) for people with chronic fatigue syndrome (CFS), clinicians are left wondering how exactly to apply exercise therapy to their patients with CFS. The aim of this literature review is to identify the appropriate exercise modalities (i.e. exercise duration, mode, number of treatment sessions, session length, duration of treatment, exercise intensity and whether or not to apply home exercise program) for people with CFS. MATERIALS AND METHODS: All studies that were identified through electronic databases (PubMed and PEDro) were assessed for methodological quality by using selection criteria (Delphi score). RESULTS: In this literature review, 12 studies fulfilled all study requirements. One study had a low methodological quality. The parameters used in the GET and CBT interventions were divided into subgroups: (i) time or symptom contingent, (ii) exercise frequency and (iii) exercise modality. CONCLUSION: The lack of uniformity in outcome measures and CFS diagnostic criteria make it difficult to compare the findings across studies. Based on the available evidence, exercise therapy for people with CFS should be aerobic and must comprise of 10-11 sessions spread over a period of 4-5 months. A time-contingent approach is preferred over a symptom-contingent way of exercising. In addition, people with CFS can perform home exercises five times a week with an initial duration of 5-15 min per exercise session. The exercise duration can be gradually increased up to 30 min.

5 Review In the mind or in the brain? Scientific evidence for central sensitisation in chronic fatigue syndrome. 2012

Nijs, Jo / Meeus, Mira / Van Oosterwijck, Jessica / Ickmans, Kelly / Moorkens, Greta / Hans, Guy / De Clerck, Luc S. ·Department of Human Physiology, Vrije Universiteit Brussel (VUB), Brussels, Belgium. Jo.Nijs@vub.ac.be ·Eur J Clin Invest · Pubmed #21793823.

ABSTRACT: BACKGROUND: Central sensitisation entails several top-down and bottom-up mechanisms, all contributing to the hyperresponsiveness of the central nervous system to a variety of inputs. In the late nineties, it was first hypothesised that chronic fatigue syndrome (CFS) is characterised by hypersensitivity of the central nervous system (i.e. central sensitisation). Since then, several studies have examined central sensitisation in patients with CFS. This study provides an overview of such studies. MATERIALS AND METHODS: Narrative review. RESULTS: Various studies showed generalised hyperalgesia in CFS for a variety of sensory stimuli, including electrical stimulation, mechanical pressure, heat and histamine. Various tissues are affected by generalised hyperalgesia: the skin, muscle tissue and the lungs. Generalised hyperalgesia in CFS is augmented, rather than decreased, following various types of stressors like exercise and noxious heat pain. Endogenous inhibition is not activated in response to exercise and activation of diffuse noxious inhibitory controls following noxious heat application to the skin is delayed. CONCLUSIONS: The observation of central sensitisation in CFS is in line with our current understanding of CFS. The presence of central sensitisation in CFS corroborates with the presence of several psychological influences on the illness, the presence of infectious agents and immune dysfunctions and the dysfunctional hypothalamus-pituitary-adrenal axis as seen in these severely debilitated patients.

6 Article Relationship Between Exercise-induced Oxidative Stress Changes and Parasympathetic Activity in Chronic Fatigue Syndrome: An Observational Study in Patients and Healthy Subjects. 2019

Polli, Andrea / Van Oosterwijck, Jessica / Nijs, Jo / Marusic, Uros / De Wandele, Inge / Paul, Lorna / Meeus, Mira / Moorkens, Greta / Lambrecht, Luc / Ickmans, Kelly. ·Pain in Motion International Research Group, Belgium(12); Department of Physiotherapy, Human Physiology and Anatomy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium; Research Foundation-Flanders (FWO), Brussels, Belgium. Electronic address: andrea.polli@vub.be. · Pain in Motion International Research Group, Belgium(12); Research Foundation-Flanders (FWO), Brussels, Belgium; Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium; Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium. · Pain in Motion International Research Group, Belgium(12); Department of Physiotherapy, Human Physiology and Anatomy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium; Department of Physical Medicine and Physiotherapy, University Hospital Brussels, Brussels, Belgium. · Institute for Kinesiology Research, Science and Research Centre Koper, Koper, Slovenia; Department of Health Sciences, Alma Mater Europaea-ECM, Maribor, Slovenia. · Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium. · School of Health and Life Sciences, Glasgow Caledonian University, Glasgow, United Kingdom. · Pain in Motion International Research Group, Belgium(12); Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium; Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium. · Department of Internal Medicine, University Hospital Antwerp (UZA), Antwerp, Belgium. · Private Practice for Internal Medicine, Ghent, Belgium. ·Clin Ther · Pubmed #30665828.

ABSTRACT: PURPOSE: Oxidative stress has been proposed as a contributor to pain in patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). During incremental exercise in patients with ME/CFS, oxidative stress enhances sooner and antioxidant response is delayed. We explored whether oxidative stress is associated with pain symptoms or pain changes following exercise, and the possible relationships between oxidative stress and parasympathetic vagal nerve activity in patients with ME/CFS versus healthy, inactive controls. METHODS: The present study reports secondary outcomes from a previous work. Data from 36 participants were studied (women with ME/CFS and healthy controls). Subjects performed a submaximal exercise test with continuous cardiorespiratory monitoring. Levels of thiobarbituric acid-reactive substances (TBARSs) were used as a measure of oxidative stress, and heart rate variability was used to assess vagal activity. Before and after the exercise, subjects were asked to rate their pain using a visual analogic scale. FINDINGS: Significant between-group differences in pain at both baseline and following exercise were found (both, P < 0.007). In healthy controls, pain was significantly improved following exercise (P = 0.002). No change in oxidative stress level after exercise was found. Significant correlation between TBARS levels and pain was found at baseline (r = 0.540; P = 0.021) and after exercise (r = 0.524; P = 0.024) in patients only. No significant correlation between TBARS and heart rate variability at baseline or following exercise was found in either group. However, a significant correlation was found between exercise-induced changes in HRV and TBARS in healthy controls (r = -0.720; P = 0.001). IMPLICATIONS: Oxidative stress showed an association with pain symptoms in people with ME/CFS, but no exercise-induced changes in oxidative stress were found. In addition, the change in parasympathetic activity following exercise partially accounted for the change in oxidative stress in healthy controls. More research is required to further explore this link.

7 Article Exercise-induce hyperalgesia, complement system and elastase activation in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome - a secondary analysis of experimental comparative studies. 2019

Polli, Andrea / Van Oosterwijck, Jessica / Meeus, Mira / Lambrecht, Luc / Nijs, Jo / Ickmans, Kelly. ·Pain in Motion Research Group, Department of Physiotherapy, Human Physiology and Anatomy, Faculty of Physical Education and Physiotherapy, Vrije Universiteit Brussels, Laarbeeklaan 103, 1090 Jette, Brussels, Belgium, Phone/Fax: +32 (0) 2 477 45 29. · Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium. · Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium. · Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, Ghent University, Antwerp, Belgium. · Private Practice for Internal Medicine, Ghent, Belgium. · Pain in Motion Research Group, Department of Physiotherapy, Human Physiology and Anatomy, Faculty of Physical Education and Physiotherapy, Vrije Universiteit Brussels, Laarbeeklaan 103, 1090 Jette, Brussels, Belgium. ·Scand J Pain · Pubmed #30325737.

ABSTRACT: Background and aims The interaction between the immune system and pain has been thoroughly explored in the recent decades. The release of inflammatory mediators from immune cells has the capability of activating neurons and glial cells, in turn sensitizing the nervous system. Both immune system alterations and pain modulation dysfunctions have been shown in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) following exercise. However, no studies tried to explore whether these two phenomena are linked and can explain exercise-induced symptoms worsening in people with ME/CFS. We hypothesized that exercise-induced changes in descending pain modulation is associated to changes in immune system functions. We used complement system product C4a and elastase activity as indicators of immune system activity. Methods The study design was a secondary analysis of controlled experimental studies. Twenty-two patients with ME/CFS and 22 healthy sedentary controls were enrolled. In experiment 1, subjects performed an aerobic submaximal exercise test; in experiment 2 they underwent a self-paced exercise test. One week of rest period were set between the two exercise tests. Before and after each experiment, subjects underwent clinical assessment, pain thresholds (PPTs) measurement, and blood sampling. Immune system function was assessed measuring complement system C4a products and elastase activity. Results Changes in elastase activity were not associated to changes in PPTs. Associations were observed in the ME/CFS group between changes in PPTs and C4a products, following both types of exercise. After submaximal exercise, the change in C4a products was associated with the change in PPT at the thumb in patients (r=0.669, p=0.001). Similarly, after self-paced exercise the change in C4a products was associated witht the change in PPT at the calf in patients (r=0.429, p=0.047). No such correlations were found in healthy controls. Regression analysis showed that C4a changes after the submaximal exercise significantly predicted the change in PPTs (R2=0.236; p=0.02). Conclusions Moderate associations between exercise-induced changes in PPTs and immune system activity were found only in ME/CFS. The change in the complement system following submaximal exercise might be able to explain part of the change in patient's pain thresholds, providing evidence for a potential link between immune system alteration and dysfunctional endogenous pain modulation. These results have to be taken with caution, as only one out of three measures of PPTs was found associated with C4a changes. We cannot reject the hypothesis that C4a might therefore be a confounding factor, and changes during exercise might be mediated by other mechanism. Implications Immune system changes following exercise might contribute to exercise-induced symptoms worsening in patients with ME/CFS. However, the role of the complement system is questionable.

8 Article Cerebral Blood Flow and Heart Rate Variability in Chronic Fatigue Syndrome: A Randomized Cross-Over Study. 2018

Malfliet, Anneleen / Pas, Roselien / Brouns, Raf / De Win, Joris / Hatem, Samar M / Meeus, Mira / Ickmans, Kelly / van Hooff, Robbert-Jan / Nijs, Jo. ·Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium; Department of Physiotherapy, Physiology and Anatomy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium; "Pain in Motion" international research group, www.paininmotion.be. · Pain in Motion International Research Group, www.paininmotion.be; Department of Physiotherapy, Human Physiology and Anatomy (KIMA), Vrije Universiteit Brussel, Belgium. · Department of Neurology, Universitair Ziekenhuis Brussel, Belgium; Center for Neurosciences (C4N), Vrije Universiteit Brussel, Belgium. · Department of Physical Medicine and Rehabilitation, University Hospital Gent, Ghent University, Belgium. · Department of Physiotherapy, Human Physiology and Anatomy (KIMA), Vrije Universiteit Brussel, Belgium; Clinic of Physical Medicine and Rehabilitation, Brugmann University Hospital, Belgium; Physical Medicine and Rehabilitation, Vrije Universiteit Brussel, Belgium; Systems & Cognition division (COSY), Institute of Neuroscience, Université catholique de Louvain, Belgium. · Department of Rehabilitation Sciences and Physiotherapy, Ghent University, Belgium; Pain in Motion international research group, www.paininmotion.be; Department of Rehabilitation Sciences and Physiotherapy, University of Antwerp, Belgium. · Pain in Motion Research Group (www.paininmotion.be); Department of Physiotherapy, Human Physiology and Anatomy (KIMA), Vrije Universiteit Brussel, Belgium; Department of Physical Medicine and Physiotherapy, University Hospital Brussels, Belgium. · Pain in Motion Research Group (www.paininmotion.be); Department of Human Physiology and Physiotherapy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium; Department of Physical Medicine and Physiotherapy, University Hospital Brussels, Brussels, Belgium. ·Pain Physician · Pubmed #29357332.

ABSTRACT: BACKGROUND: Pain, fatigue, and concentration difficulties are typical features of chronic fatigue syndrome (CFS). The exact underlying mechanisms of these symptoms are still unknown, but available evidence suggests an important role for impaired pain modulation. As evidence also suggests that pain modulation is related to cardiovascular mechanisms, it seems logical to investigate whether cerebral blood flow (CBF) and heart rate variability (HRV) are altered in these patients. OBJECTIVES: We aimed to investigate the role of the cardiovascular system in pain modulation and symptoms of CFS; the response of CBF and HRV to physical stress and their relation to the change in temporal summation (TS) of pressure pain and self-reported symptoms was evaluated. STUDY DESIGN: A controlled, randomized cross-over trial. SETTING: University Hospital Brussels. METHODS: Twenty CFS patients and 20 sedentary healthy controls were included in this study. In both of the groups, the change in TS of pressure pain, CBF (using transcranial Doppler), and HRV (using finger plethysmography) was examined during physical and emotional stress (to control for potential bias), as well as their association mutually and with self-reported symptoms of pain, fatigue, and concentrations difficulties. RESULTS: There was no significant interaction or group (F-values ranging from .100 to 1.862, P-values ranging from .754 to .181) effect in CBF or HRV parameters. HRV and CBF did change during physical exercise, but the changes did not differ between patients and controls. While pain scores during TS at the trapezius site reduced in the control group after the physical exercise protocol (P = .037), they did not change in the CFS group (P = .108), suggesting impaired pain modulation. There were no significant correlations between CBF, HRV, TS, and self-reported symptoms (all P-values of correlation analyses > .01). LIMITATIONS: Although effect sizes were medium to large, the study sample was relatively low. Also, the mild nature of the exercise bout is discussable. Nonetheless, this mild exercise was able to provoke endogenous pain modulation in the control group, which endorsed a proper execution of the cycling exercise. Moreover, mild exercises are more applicable to daily physical activities in CFS patients than vigorous exercises. CONCLUSION: These results seem to refute the previously suggested alterations of CBF/HRV in CFS patients. These cardiovascular parameters appear not to explain pain before, during, and following exercise. KEY WORDS: Chronic pain, physical exercise, emotional stress, pain modulation, cardiovascular systems, temporal summation, pain pressure thresholds, transcranial Doppler, plethysmography.

9 Article Endogenous Pain Facilitation Rather Than Inhibition Differs Between People with Chronic Fatigue Syndrome, Multiple Sclerosis, and Controls: An Observational Study. 2017

Collin, Simon M / Nijs, Jo / Meeus, Mira / Polli, Andrea / Willekens, Barbara / Ickmans, Kelly. ·School of Social & Community Medicine, University of Bristol, Bristol, UK. · Pain in Motion Research Group (www.paininmotion.be); Department of Human Physiology and Physiotherapy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium; Department of Physical Medicine and Physiotherapy, University Hospital Brussels, Brussels, Belgium. · Pain in Motion Research Group (www.paininmotion.be); Rehabilitation Sciences and Physiotherapy, Faculty of Medicine & Health Sciences, Ghent University, Ghent, Belgium; Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine & Health Sciences, University of Antwerp, Antwerp, Belgium. · Pain in Motion Research Group, www.paininmotion.be; Department of Physiotherapy, Human Physiology and Anatomy, Faculty of Physical Education & Physiotherapy (KIMA), Vrije Universiteit Brussel, Belgium. · Department of Neurology, Antwerp University Hospital, Belgium; Department of Neurology, Faculty of Medicine and Health Sciences, University of Antwerp, Belgium. · Pain in Motion Research Group (www.paininmotion.be). ·Pain Physician · Pubmed #28535557.

ABSTRACT: BACKGROUND: Commonalities in the core symptoms of fatigue and cognitive dysfunction experienced by chronic fatigue syndrome (CFS, also known as ME) and multiple sclerosis (MS) patients have been described. Many CFS and MS patients also experience chronic pain, which has been attributed to central sensitization in both groups of patients. However, the characteristics of pain in CFS and MS patients have not been compared. OBJECTIVES: To compare experimental pain measurements in patients with CFS or MS and healthy controls. STUDY DESIGN: Observational study. SETTING: This study took place in Belgium at Vrije Universiteit Brussel and the University of Antwerp. METHODS: Pressure pain thresholds, temporal summation, conditioned pain modulation, and occlusion cuff pressure thresholds rated as painful (1st cuff pressure threshold) and as 3/10 on a verbal numerical scale (2nd cuff pressure threshold) were measured in patients with CFS (n = 48), MS (n = 19) and healthy pain-free controls (n = 30). Adjusted between-group differences were estimated using linear regression models. RESULTS: Finger pain pressure thresholds of patients with CFS, compared with patients with MS, were 25% lower (difference ratio 0.75 [95% CI 0.59, 0.95], P = 0.02) and shoulder pain pressure thresholds were 26% lower (difference ratio 0.74 [0.52, 1.04], P = 0.08). Compared with patients with MS, patients with CFS had 29% lower first cuff pressure threshold (difference ratio 0.71 [0.53, 0.94], P = 0.02) and 41% lower 2nd cuff pressure threshold (0.59 [0.41, 0.86], P = 0.006). Finger temporal summation was higher in patients with CFS than in patients with MS (mean difference 1.15 [0.33, 1.97], P = 0.006), but there were no differences in shoulder temporal summation or conditioned pain modulation at either site. Differences between patients with CFS and MS tended to be greater than between either patient group and healthy controls. Pain pressure thresholds and cuff pressure thresholds tended to be positively correlated, and temporal summation negatively correlated, with higher physical function and lower fatigue in both groups of patients. Subjective pain in patients with CFS but not in patients with MS was strongly negatively correlated with pain pressure thresholds and cuff pressure thresholds, and positively correlated with temporal summation. LIMITATIONS: The main limitations of our study are the relatively small sample sizes, its cross-sectional design, and its exploratory nature. CONCLUSIONS: We found differences in the characteristics of pain symptoms reported by patients with CFS and patients with MS, which suggest different underlying mechanisms. Specifically, overactive endogenous pain facilitation was characteristic of pain in patients with CFS but not in patients with MS, suggesting a greater role for central sensitization in CFS.

10 Article What is in a name? Comparing diagnostic criteria for chronic fatigue syndrome with or without fibromyalgia. 2016

Meeus, Mira / Ickmans, Kelly / Struyf, Filip / Kos, Daphne / Lambrecht, Luc / Willekens, Barbara / Cras, Patrick / Nijs, Jo. ·Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium. mira.meeus@ugent.be. · Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium. mira.meeus@ugent.be. · Pain in Motion International Research Group, . mira.meeus@ugent.be. · Rehabilitation Sciences and Physiotherapy, Ghent University, Campus Heymans (UZ) 3 B3, De Pintelaan 185, Ghent, Belgium. mira.meeus@ugent.be. · Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium. · Pain in Motion International Research Group. · Departments of Human Physiology and & Rehabilitation Sciences, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussel, Belgium. · Department of Physiotherapy and Rehabilitation, University Hospital Brussels, Brussel, Belgium. · Division of Occupational Therapy, Artesis Plantijn University College Antwerp, Antwerp, Belgium. · Rehabilitation Sciences, KU Leuven, Leuven, Belgium. · Private practice for internal medicine, Ghent, Belgium. · Department of Neurology, Faculty of Medicine, University and University Hospital Antwerp, Antwerp, Belgium. ·Clin Rheumatol · Pubmed #25308475.

ABSTRACT: The current study had two objectives. (1) to compare objective and self-report measures in patients with chronic fatigue syndrome (CFS) according to the 1994 Center for Disease Control (CDC) criteria, patients with multiple sclerosis (MS), and healthy controls, and (2) to contrast CFS patients who only fulfill CDC criteria to those who also fulfill the criteria for myalgic encephalomyelitis (ME), the 2003 Canadian criteria for ME/CFS, or the comorbid diagnosis of fibromyalgia (FM). One hundred six participants (48 CFS patients diagnosed following the 1994 CDC criteria, 19 MS patients, and 39 healthy controls) completed questionnaires assessing symptom severity, quality of life, daily functioning, and psychological factors. Objective measures consisted of activity monitoring, evaluation of maximal voluntary contraction and muscle recovery, and cognitive performance. CFS patients were screened whether they also fulfilled ME criteria, the Canadian criteria, and the diagnosis of FM. CFS patients scored higher on symptom severity, lower on quality of life, and higher on depression and kinesiophobia and worse on MVC, muscle recovery, and cognitive performance compared to the MS patients and the healthy subjects. Daily activity levels were also lower compared to healthy subjects. Only one difference was found between those fulfilling the ME criteria and those who did not regarding the degree of kinesiophobia (lower in ME), while comorbidity for FM significantly increased the symptom burden. CFS patients report more severe symptoms and are more disabled compared to MS patients and healthy controls. Based on the present study, fulfillment of the ME or Canadian criteria did not seem to give a clinically different picture, whereas a diagnosis of comorbid FM selected symptomatically worse and more disabled patients.

11 Article Associations Between Cognitive Performance and Pain in Chronic Fatigue Syndrome: Comorbidity with Fibromyalgia Does Matter. 2015

Ickmans, Kelly / Meeus, Mira / De Kooning, Margot / Lambrecht, Luc / Pattyn, Nathalie / Nijs, Jo. ·Pain in Motion Research Group (www.paininmotion.be). · 1Pain in Motion Research Group (www.paininmotion.be); Rehabilitation Sciences and Physiotherapy, Faculty of Medicine & Health Sciences, Ghent University, Ghent, Belgium; Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine & Health Sciences, University of Antwerp, Antwerp, Belgium. · Pain in Motion Research Group (www.paininmotion.be); Department of Human Physiology and Physiotherapy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium; Department of Physical Medicine and Physiotherapy, University Hospital Brussels, Brussels, Belgium; Department of Neurology, Faculty of Medicine, University of Antwerp, Antwerp, Belgium. · Private practice for internal medicine, Ghent, Belgium. · Department of Human Physiology and Physiotherapy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium; VIPER Research Unit, Royal Military Academy, Brussels, Belgium. · Pain in Motion Research Group (www.paininmotion.be); Department of Human Physiology and Physiotherapy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium; Department of Physical Medicine and Physiotherapy, University Hospital Brussels, Brussels, Belgium; ·Pain Physician · Pubmed #26431138.

ABSTRACT: BACKGROUND: In addition to the frequently reported pain complaints, performance-based cognitive capabilities in patients with chronic fatigue syndrome (CFS) with and without comorbid fibromyalgia (FM) are significantly worse than those of healthy controls. In various chronic pain populations, cognitive impairments are known to be related to pain severity. However, to the best of our knowledge, the association between cognitive performance and experimental pain measurements has never been examined in CFS patients. OBJECTIVES: This study aimed to examine the association between cognitive performance and self-reported as well as experimental pain measurements in CFS patients with and without FM. STUDY DESIGN: Observational study. SETTING: The present study took place at the Vrije Universiteit Brussel and the University of Antwerp. METHODS: Forty-eight (18 CFS-only and 30 CFS+FM) patients and 30 healthy controls were studied. Participants first completed 3 performance-based cognitive tests designed to assess selective and sustained attention, cognitive inhibition, and working memory capacity. Seven days later, experimental pain measurements (pressure pain thresholds [PPT], temporal summation [TS], and conditioned pain modulation [CPM]) took place and participants were asked to fill out 3 questionnaires to assess self-reported pain, fatigue, and depressive symptoms. RESULTS: In the CFS+FM group, the capacity of pain inhibition was significantly associated with cognitive inhibition. Self-reported pain was significantly associated with simple reaction time in CFS-only patients. The CFS+FM but not the CFS-only group showed a significantly lower PPT and enhanced TS compared with controls. LIMITATIONS: The cross-sectional nature of this study does not allow for inferences of causation. CONCLUSIONS: The results underline disease heterogeneity in CFS by indicating that a measure of endogenous pain inhibition might be a significant predictor of cognitive functioning in CFS patients with FM, while self-reported pain appears more appropriate to predict cognitive functioning in CFS patients without FM.

12 Article Sleep characteristics, exercise capacity and physical activity in patients with chronic fatigue syndrome. 2015

Aerenhouts, Dirk / Ickmans, Kelly / Clarys, Peter / Zinzen, Evert / Meersdom, Geert / Lambrecht, Luc / Nijs, Jo. ·a Department of Human Biometry and Biomechanics , and. · b Department of Movement Education and Sports Training , Vrije Universiteit Brussel , Brussels , Belgium . · c Pain in Motion Research Group . · d Department of Human Physiology and Rehabilitation Sciences , Vrije Universiteit Brussel , Brussels , Belgium . · e Department of Physical Medicine and Physiotherapy , University Hospital Brussels , Brussels , Belgium . · f CVS Contactgroep Belgium , Brugge , Belgium , and. · g Private Practice for Internal Medicine , Ghent , Belgium. ·Disabil Rehabil · Pubmed #25512240.

ABSTRACT: PURPOSE: Unrefreshing sleep and lowered physical activity are commonly observed in chronic fatigue syndrome (CFS) patients, but how they might influence each other remains unexplored. Therefore, this study simultaneously examined the exercise capacity, sleep characteristics and physical activity in CFS patients. METHODS: Handgrip strength and cycle exercise capacity were assessed in 42 female CFS patients and 24 inactive control subjects. During four consecutive days and nights, energy expenditure, activity and sleep-wake pattern were objectively registered using a Sensewear Armband. RESULTS: Exercise capacity was significantly lower in CFS patients. In both groups VO2peak correlated with the time subjects were physically active. In CFS patients only, VO2peak correlated negatively with sleeping during the day whilst physical activity level and energy expenditure correlated negatively with sleep latency and lying awake at night. CONCLUSIONS: In the present study, CFS patients with higher VO2peak tend to sleep less over day. Occupation in physical activities was negatively associated with sleep latency and lying awake at night. Increased physical activity potentially has beneficial effects on sleep quality in CFS. However, a close monitoring of the effects of increasing physical activity is essential to avoid negative effects on the health status of patients. IMPLICATIONS FOR REHABILITATION: Female patients with chronic fatigue syndrome (CFS) have normal sleep latency and sleep efficiency, but sleep more and spent more time in bed as compared to healthy inactive women. Female CFS patients have lower exercise capacity, and a lower physical activity level as compared to healthy inactive women. CFS patients appear to be more sensitive for sleep quality (sleep latency and lying awake at night), which is associated with a low physical activity level.

13 Article Endogenous pain modulation in response to exercise in patients with rheumatoid arthritis, patients with chronic fatigue syndrome and comorbid fibromyalgia, and healthy controls: a double-blind randomized controlled trial. 2015

Meeus, Mira / Hermans, Linda / Ickmans, Kelly / Struyf, Filip / Van Cauwenbergh, Deborah / Bronckaerts, Laura / De Clerck, Luc S / Moorken, Greta / Hans, Guy / Grosemans, Sofie / Nijs, Jo. ·Departments of Human Physiology and Rehabilitation Sciences, Faculty of Physical Education and Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium; Department of Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Rehabilitation Sciences and Physiotherapy, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium; "Pain in Motion" Research Group. ·Pain Pract · Pubmed #24528544.

ABSTRACT: OBJECTIVE: Temporal summation (TS) of pain, conditioned pain modulation (CPM), and exercise-induced analgesia (EIA) are often investigated in chronic pain populations as an indicator for enhanced pain facilitation and impaired endogenous pain inhibition, respectively, but interactions are not yet clear both in healthy controls and in chronic pain patients. Therefore, the present double-blind randomized placebo-controlled study evaluates pains cores, TS, and CPM in response to exercise in healthy controls, patients with chronic fatigue syndrome and comorbid fibromyalgia (CFS/FM), and patients with rheumatoid arthritis (RA), both under placebo and paracetamol condition. METHODS: Fifty-three female volunteers - of which 19 patients with CFS/FM, 16 patients with RA, and 18 healthy controls - underwent a submaximal exercise test on a bicycle ergometer on 2 different occasions (paracetamol vs. placebo), with an interval of 7 days. Before and after exercise, participants rated pain intensity during TS and CPM. RESULTS: Patients with rheumatoid arthritis showed decreased TS after exercise, both after paracetamol and placebo (P < 0.05). In patients with CFS/FM, results were less univocal. A nonsignificant decrease in TS was only observed after taking paracetamol. CPM responses to exercise are inconclusive, but seem to worsen after exercise. No adverse effects were seen. CONCLUSION: This study evaluates pain scores, TS, and CPM in response to submaximal exercise in 2 different chronic pain populations and healthy controls. In patients with RA, exercise had positive effects on TS, suggesting normal EIA. In patients with CFS/FM, these positive effects were only observed after paracetamol and results were inconsistent.

14 Article Can recovery of peripheral muscle function predict cognitive task performance in chronic fatigue syndrome with and without fibromyalgia? 2014

Ickmans, Kelly / Meeus, Mira / De Kooning, Margot / Lambrecht, Luc / Pattyn, Nathalie / Nijs, Jo. ·K. Ickmans, PT, MSc, Pain in Motion Research Group, Department of Human Physiology and Physiotherapy, Faculty of Physical Education and Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium; Pain in Motion Research Group, Division of Musculoskeletal Physiotherapy, Department of Health Care Sciences, Artesis University College, Antwerp, Belgium; and Pain in Motion Research Group, Department of Physical Medicine and Physiotherapy, University Hospital Brussels, Brussels, Belgium. ·Phys Ther · Pubmed #24363336.

ABSTRACT: BACKGROUND: Both good physical and cognitive functioning have a positive influence on the execution of activities of daily living. Patients with chronic fatigue syndrome (CFS) as well as patients with fibromyalgia have marked cognitive deficits. Furthermore, a good physical and functional health status may have a positive impact on a variety of cognitive skills-a link that has been observed in young and old individuals who are healthy, although evidence is limited in patients with CFS. OBJECTIVE: The purpose of this study was to examine whether recovery of upper limb muscle function could be a significant predictor of cognitive performance in patients with CFS and in patients with CFS and comorbid fibromyalgia. Furthermore, this study determined whether cognitive performance is different between these patient groups. DESIGN: A case-control design was used. METHODS: Seventy-eight participants were included in the study: 18 patients with CFS only (CFS group), 30 patients with CFS and comorbid fibromyalgia (CFS+FM group), and 30 individuals who were healthy and inactive (control group) were studied. Participants first completed 3 performance-based cognitive tests designed to assess selective and sustained attention, cognitive inhibition, and working memory capacity. Seven days later, they performed a fatiguing upper limb exercise test, with subsequent recovery measures. RESULTS: Recovery of upper limb muscle function was found to be a significant predictor of cognitive performance in patients with CFS. Participants in the CFS+FM group but not those in the CFS group showed significantly decreased cognitive performance compared with the control group. LIMITATIONS: The cross-sectional nature of this study does not allow for inferences of causation. CONCLUSIONS: The results suggest that better physical health status could predict better mental health in patients with CFS. Furthermore, they underline disease heterogeneity, suggesting that reducing this factor in future research is important to better understand and uncover mechanisms regarding the nature of diverse impairments in these patients.

15 Article Recovery of upper limb muscle function in chronic fatigue syndrome with and without fibromyalgia. 2014

Ickmans, Kelly / Meeus, Mira / De Kooning, Margot / Lambrecht, Luc / Nijs, Jo. ·Pain in Motion Research Group, Department of Human Physiology and Physiotherapy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussel, Belgium; Pain in Motion Research Group, Division of Musculoskeletal Physiotherapy, Department of Health Care Sciences, Artesis University College Antwerp, Antwerp, Belgium; Pain in Motion Research Group, Department of Physical Medicine and Physiotherapy, University Hospital Brussels, Brussels, Belgium. ·Eur J Clin Invest · Pubmed #24313704.

ABSTRACT: BACKGROUND: Chronic fatigue syndrome (CFS) patients frequently complain of muscle fatigue and abnormally slow recovery, especially of the upper limb muscles during and after activities of daily living. Furthermore, disease heterogeneity has not yet been studied in relation to recovery of muscle function in CFS. Here, we examine recovery of upper limb muscle function from a fatiguing exercise in CFS patients with (CFS+FM) and without (CFS-only) comorbid fibromyalgia and compare their results with a matched inactive control group. DESIGN: In this case-control study, 18 CFS-only patients, 30 CFS+FM patients and 30 healthy inactive controls performed a fatiguing upper limb exercise test with subsequent recovery measures. RESULTS: There was no significant difference among the three groups for maximal handgrip strength of the non-dominant hand. A significant worse recovery of upper limb muscle function was found in the CFS+FM, but not in de CFS-only group compared with the controls (P < 0·05). CONCLUSIONS: This study reveals, for the first time, delayed recovery of upper limb muscle function in CFS+FM, but not in CFS-only patients. The results underline that CFS is a heterogeneous disorder suggesting that reducing the heterogeneity of the disorder in future research is important to make progress towards a better understanding and uncovering of mechanisms regarding the nature of divers impairments in these patients.

16 Article Association between cognitive performance, physical fitness, and physical activity level in women with chronic fatigue syndrome. 2013

Ickmans, Kelly / Clarys, Peter / Nijs, Jo / Meeus, Mira / Aerenhouts, Dirk / Zinzen, Evert / Aelbrecht, Senne / Meersdom, Geert / Lambrecht, Luc / Pattyn, Nathalie. ·Pain in Motion Research Group (PIM), Department of Human Physiology, Vrije Universiteit Brussel, Brussels, Belgium. ·J Rehabil Res Dev · Pubmed #24203542.

ABSTRACT: Limited scientific evidence suggests that physical activity is directly related to cognitive performance in patients with chronic fatigue syndrome (CFS). To date, no other study has examined the direct relationship between cognitive performance and physical fitness in these patients. This study examined whether cognitive performance and physical fitness are associated in female patients with CFS and investigated the association between cognitive performance and physical activity level (PAL) in the same study sample. We hypothesized that patients who performed better on cognitive tasks would show increased PALs and better performance on physical tests. The study included 31 women with CFS and 13 healthy inactive women. Participants first completed three cognitive tests. Afterward, they undertook a test to determine their maximal handgrip strength, performed a bicycle ergometer test, and were provided with an activity monitor. In patients with CFS, lower peak oxygen uptake and peak heart rate were associated with slower psychomotor speed (p < 0.05). Maximal handgrip strength was correlated with working memory performance (p < 0.05). Both choice and simple reaction time were lower in patients with CFS relative to healthy controls (p < 0.05 and p < 0.001, respectively). In conclusion, physical fitness, but not PAL, is associated with cognitive performance in female patients with CFS.

17 Article Cognitive performance is of clinical importance, but is unrelated to pain severity in women with chronic fatigue syndrome. 2013

Ickmans, Kelly / Meeus, Mira / Kos, Daphne / Clarys, Peter / Meersdom, Geert / Lambrecht, Luc / Pattyn, Nathalie / Nijs, Jo. ·Pain in Motion Research Group (PIM), Department of Human Physiology, Faculty of Physical Education and Physiotherapy, Vrije Universiteit Brussel, Building L, Pleinlaan 2, 1050, Brussels, Belgium. ·Clin Rheumatol · Pubmed #23737111.

ABSTRACT: In various chronic pain populations, decreased cognitive performance is known to be related to pain severity. Yet, this relationship has not been investigated in patients with chronic fatigue syndrome (CFS). This study investigated the relationship between cognitive performance and (1) pain severity, (2) level of fatigue, and (3) self-reported symptoms and health status in women with CFS. Examining the latter relationships is important for clinical practice, since people with CFS are often suspected to exaggerate their symptoms. A sample of 29 female CFS patients and 17 healthy controls aged 18 to 45 years filled out three questionnaires (Medical Outcomes Study 36-Item Short-Form Health Survey, Checklist Individual Strength (CIS), and CFS Symptom List) and performed three performance-based cognitive tests (psychomotor vigilance task, Stroop task, and operation span task), respectively. In both groups, pain severity was not associated with cognitive performance. In CFS patients, the level of fatigue measured with the CFS Symptom List, but not with the CIS, was significantly correlated with sustained attention. Self-reported mental health was negatively correlated with all investigated cognitive domains in the CFS group. These results provide evidence for the clinical importance of objectively measured cognitive problems in female CFS patients. Furthermore, a state-like measure (CFS Symptom List) appears to be superior over a trait-like measure (CIS) in representing cognitive fatigue in people with CFS. Finally, the lack of a significant relationship between cognitive performance and self-reported pain severity suggests that pain in CFS might be unique.

18 Article Does acetaminophen activate endogenous pain inhibition in chronic fatigue syndrome/fibromyalgia and rheumatoid arthritis? A double-blind randomized controlled cross-over trial. 2013

Meeus, Mira / Ickmans, Kelly / Struyf, Filip / Hermans, Linda / Van Noesel, Kevin / Oderkerk, Jorinde / Declerck, Luc S / Moorkens, Greta / Hans, Guy / Grosemans, Sofie / Nijs, Jo. ·Department of Human Physiology and Rehabilitation Sciences, Vrije Universiteit Brussels, Belgium. Mira.Meeus@artesis.be ·Pain Physician · Pubmed #23511692.

ABSTRACT: BACKGROUND: Although enhanced temporal summation (TS) and conditioned pain modulation (CPM), as characteristic for central sensitization, has been proved to be impaired in different chronic pain populations, the exact nature is still unknown. OBJECTIVES: We examined differences in TS and CPM in 2 chronic pain populations, patients with both chronic fatigue syndrome (CFS) and comorbid fibromyalgia (FM) and patients with rheumatoid arthritis (RA), and in sedentary, healthy controls, and evaluated whether activation of serotonergic descending pathways by acetaminophen improves central pain processing. STUDY DESIGN: Double-blind randomized controlled trial with cross-over design. METHODS: Fifty-three women (19 CFS/FM patients, 16 RA patients, and 18 healthy women) were randomly allocated to the experimental group (1 g acetaminophen) or the placebo group (1 g dextrose). Participants underwent an assessment of endogenous pain inhibition, consisting of an evaluation of temporal summation with and without conditioned pain modulation (CPM). Seven days later groups were crossed-over. Patients and assessors were blinded for the allocation. RESULTS: After intake of acetaminophen, pain thresholds increased slightly in CFS/FM patients, and decreased in the RA and the control group. Temporal summation was reduced in the 3 groups and CPM at the shoulder was better overall, however only statistically significant for the RA group. Healthy controls showed improved CPM for both finger and shoulder after acetaminophen, although not significant. LIMITATIONS: The influence of acetaminophen on pain processing is inconsistent, especially in the patient groups examined. CONCLUSION: This is the first study comparing the influence of acetaminophen on central pain processing in healthy controls and patients with CFS/FM and RA. It seems that CFS/FM patients present more central pain processing abnormalities than RA patients, and that acetaminophen may have a limited positive effect on central pain inhibition, but other contributors have to be identified and evaluated.

19 Minor Response. 2013

Ickmans, Kelly / Meeus, Mira / Nijs, Jo. ·Pain in Motion Group, Department of Human Physiology and Physiotherapy, Faculty of Physical Education and Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium. ·J Rehabil Res Dev · Pubmed #24458971.

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