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Papers by Kelly Ickmans

BACKGROUND: An acupuncture treatment can reduce pain sensitivity in patients with chronic whiplas... more BACKGROUND:
An acupuncture treatment can reduce pain sensitivity in patients with chronic whiplash associated disorders (WAD). But it has been hypothesized that many of the experimental results in acupuncture research could be interpreted as stress-induced analgesia.
OBJECTIVE:
The present study aimed at examining whether acupuncture has an effect on the autonomic nervous system response in patients with chronic WAD and if this response is related to the pain inhibition after an acupuncture session.
STUDY DESIGN:
Randomized crossover trial with blinded assessor.
SETTING:
Two private practices.
METHODS:
Thirty-nine patients with chronic WAD received 2 treatment sessions of identical duration, with acupuncture and relaxation therapy randomly crossed over in the 2 visits. The primary outcome measurement was the registration of autonomic nervous system parameters (heart rate, skin conductance, and heart rate variability parameters) during the administration of experimental pain. Endogenous analgesia was the secondary outcome.
RESULTS:
Following one acupuncture treatment session, there was a significant change for 2 parameters: the heart rate was slightly reduced and the skin conductance was raised. Comparing the effects of acupuncture and relaxation, no differences were found with respect to the change in any of the autonomic parameters. Further, the reduction in pain sensitivity in response to acupuncture treatment was unrelated to any of the changes in autonomic measurements.
LIMITATIONS:
The results were observed after only one session of acupuncture.
CONCLUSION:
In patients with chronic WAD, in response to a single treatment session, no acupuncture specific effects on the autonomic response to pain assessment were present and the analgesia after one session of acupuncture is not caused by stress-induced analgesia but is more likely the result of an acupuncture specific reaction.
KEY WORDS:
Acupuncture, chronic whiplash, autonomic nervous system, pain analgesia, heart rate variability, acupuncture analgesia.

Pain physician

Low back pain (LBP) is a heterogeneous disorder including patients with dominant nociceptive (e.g... more Low back pain (LBP) is a heterogeneous disorder including patients with dominant nociceptive (e.g., myofascial low back pain), neuropathic (e.g., lumbar radiculopathy), and central sensitization pain. In order to select an effective and preferably also efficient treatment in daily clinical practice, LBP patients should be classified clinically as either predominantly nociceptive, neuropathic, or central sensitization pain. To explain how clinicians can differentiate between nociceptive, neuropathic, and central sensitization pain in patients with LBP. Narrative review and expert opinion Universities, university hospitals and private practices Recently, a clinical method for the classification of central sensitization pain versus neuropathic and nociceptive pain was developed. It is based on a body of evidence of original research papers and expert opinion of 18 pain experts from 7 different countries. Here we apply this classification algorithm to the LBP population. The first step ...

Pain physician

A growing body of research has demonstrated that impaired central pain modulation or central sens... more A growing body of research has demonstrated that impaired central pain modulation or central sensitization (CS) is a crucial mechanism for the development of persistent pain in chronic whiplash-associated disorders (WAD) and fibromyalgia (FM) patients. Furthermore, there is increasing evidence for cognitive dysfunctions among these patients. In addition, chronic WAD and FM patients often report problems with health-related quality of life (QoL). Yet, there is limited research concerning the interrelations between cognitive performance, indices of CS, and health-related QoL in these patients. (1) Examining the presence of cognitive impairment, CS, and limitations on health-related QoL in patients with chronic WAD and FM compared to healthy controls. (2) Examining interrelations between performance-based cognitive functioning, CS, and self-reported health-related QoL in these 3 study groups. A case-control study was conducted. The present study took place at the University Hospital Br...

Pain physician

In addition to the frequently reported pain comp laints, performance-based cognitive capabilities... more In addition to the frequently reported pain comp laints, 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. 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. Observational study. The present study took place at the Vrije Universiteit Brussel and the University of Antwerp. 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 attentio...

Journal of rehabilitation research and development, 2013

Pain physician

Although enhanced temporal summation (TS) and conditioned pain modulation (CPM), as characteristi... more 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. 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. Double-blind randomized controlled trial with cross-over design. 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 (CP...

Pain physician

Until now, there is no firm evidence for conservative therapy in patients with chronic Whiplash A... more Until now, there is no firm evidence for conservative therapy in patients with chronic Whiplash Associated Disorders (WAD). While chronic WAD is a biopsychosocial problem, education may be an essential part in the treatment and the prevention of chronic WAD. However, it is still unclear which type of educative intervention has already been used in WAD patients and how effective such interventions are. This systematic literature study aimed at providing an overview of the literature regarding the currently existing educative treatments for patients with whiplash or WAD and their evidence. Systematic review of the literature. A systematic literature search was conducted in the following databases: Pubmed, Springerlink, and Web of Science using different keyword combinations. We included randomized controlled clinical trials (RCT) that encompass the effectiveness of education for patients with WAD. The included articles were evaluated on their methodological quality. Ten RCT's of m...

In vivo (Athens, Greece)

We examined whether activation of serotonergic descending pathways improves pain inhibition durin... more We examined whether activation of serotonergic descending pathways improves pain inhibition during exercise in patients with chronic fatigue syndrome (CFS) and comorbid fibromyalgia (FM) in comparison with rheumatoid arthritis (RA) and sedentary, healthy controls in a double-blind randomized controlled trial with cross-over design. Three female CFS/FM patients, one female RA patient and two healthy women were randomly allocated to the experimental group (2 ml of citalopram intravenously) or the placebo group (2 ml of 0.9% NaCl intravenously). Participants performed a submaximal exercise protocol, preceded and followed by an assessment of endogenous pain inhibition. Seven days later, groups were crossed over. Significant side-effects were observed in all, but one participant immediately after intravenous administration of citalopram. One CFS/FM patient withdrew because of severe post-exertional malaise. It was decided that proceeding with the study would be unethical. No conclusion c...

Pain Practice, 2014

Temporal summation (TS) of pain, conditioned pain modulation (CPM), and exercise-induced analgesi... more 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. 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. 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. 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.

Expert Opinion on Pharmacotherapy, 2014

Exercise immunology review, 2014

An increasing number of studies have examined how the immune system of patients with Chronic Fati... more 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 delaye...

Disability and Rehabilitation, 2014

Abstract Purpose: Unrefreshing sleep and lowered physical activity are commonly observed in chron... more 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.

Clinical Neurology and Neurosurgery, 2014

Delayed recovery of muscle function following exercise has been demonstrated in the lower limbs o... more Delayed recovery of muscle function following exercise has been demonstrated in the lower limbs of patients with multiple sclerosis (MS). However, studies examining this in the upper limbs are currently lacking. This study compared physical activity level (PAL) and recovery of upper limb muscle function following exercise between MS patients and healthy inactive controls. Furthermore, the relationship between PAL and muscle recovery was examined. PAL of 19 MS patients and 32 controls was measured using an accelerometer for 7 consecutive days. Afterwards, recovery of muscle function was assessed by performing a fatiguing upper limb exercise test with subsequent recovery measures. Muscle recovery of the upper limb muscles was similar in both groups. Average activity counts were significantly lower in MS patients than in the control group. MS patients spent significantly more time being sedentary and less time on activities of moderate intensity compared with the control group. No significant correlation between PAL and recovery of muscle function was found in MS patients. Recovery of upper limb muscle function following exercise is normal in MS patients. MS patients are less physically active than healthy inactive controls. PAL and recovery of upper limb muscle function appear unrelated in MS patients.

Clinical Rheumatology, 2014

Physical Therapy, 2014

Both good physical and cognitive functioning have a positive influence on the execution of activi... more 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. 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. A case-control design was used. 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. 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. The cross-sectional nature of this study does not allow for inferences of causation. 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.

Neuroscience Letters, 2011

Methods: The brain signatures of CFS screened patients (n = 30) admitted to a U.K.-based clinic w... more Methods: The brain signatures of CFS screened patients (n = 30) admitted to a U.K.-based clinic were assessed using a full-head 19 channel Quantitative EEG (electroencephalography) during 5 min of eyes open/closed at rest, and while performing a 20 min Visual Continuous Performance Task (VCPT). Following spectral and topographical analysis the data was compared to the Russian Academy of Sciences Human Brain Institute (HBI) normative database for statistically significant differences. In addition, associations between the data and symptom severity scales were also investigated.

Journal of Rehabilitation Research and Development, 2013

Limited scientific evidence suggests that physical activity is directly related to cognitive perf... more 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.

Journal of Internal Medicine, 2013

ABSTRACT In this issue of the Journal of Internal Medicine, Lewis and colleagues [1] provide comp... more ABSTRACT In this issue of the Journal of Internal Medicine, Lewis and colleagues [1] provide compelling data for a novel subgroup within the chronic fatigue syndrome (CFS) population. They show that approximately 13% (24/179) of CFS patients have postural orthostatic tachycardia syndrome (POTS), a form of dysautonomia implying that when patients change their body position from supine to upright, their heart rate will increase abnormally (tachycardia). POTS is associated with several symptoms often seen in CFS patients: fatigue, lightheadedness, dizziness, neurocognitive deficits and exercise intolerance. Importantly, this was a confirmatory study of a previously published pilot study that found a prevalence rate for POTS of 29% in a smaller sample (n=63) of CFS patients [2]. Another significant finding is the differences in fatigue severity, depressive thoughts, and daytime hypersomnolence between CFS patients with and without POTS, providing evidence for the clinical importance of POTS in CFS. © 2013 The Association for the Publication of the Journal of Internal Medicine.

BACKGROUND: An acupuncture treatment can reduce pain sensitivity in patients with chronic whiplas... more BACKGROUND:
An acupuncture treatment can reduce pain sensitivity in patients with chronic whiplash associated disorders (WAD). But it has been hypothesized that many of the experimental results in acupuncture research could be interpreted as stress-induced analgesia.
OBJECTIVE:
The present study aimed at examining whether acupuncture has an effect on the autonomic nervous system response in patients with chronic WAD and if this response is related to the pain inhibition after an acupuncture session.
STUDY DESIGN:
Randomized crossover trial with blinded assessor.
SETTING:
Two private practices.
METHODS:
Thirty-nine patients with chronic WAD received 2 treatment sessions of identical duration, with acupuncture and relaxation therapy randomly crossed over in the 2 visits. The primary outcome measurement was the registration of autonomic nervous system parameters (heart rate, skin conductance, and heart rate variability parameters) during the administration of experimental pain. Endogenous analgesia was the secondary outcome.
RESULTS:
Following one acupuncture treatment session, there was a significant change for 2 parameters: the heart rate was slightly reduced and the skin conductance was raised. Comparing the effects of acupuncture and relaxation, no differences were found with respect to the change in any of the autonomic parameters. Further, the reduction in pain sensitivity in response to acupuncture treatment was unrelated to any of the changes in autonomic measurements.
LIMITATIONS:
The results were observed after only one session of acupuncture.
CONCLUSION:
In patients with chronic WAD, in response to a single treatment session, no acupuncture specific effects on the autonomic response to pain assessment were present and the analgesia after one session of acupuncture is not caused by stress-induced analgesia but is more likely the result of an acupuncture specific reaction.
KEY WORDS:
Acupuncture, chronic whiplash, autonomic nervous system, pain analgesia, heart rate variability, acupuncture analgesia.

Pain physician

Low back pain (LBP) is a heterogeneous disorder including patients with dominant nociceptive (e.g... more Low back pain (LBP) is a heterogeneous disorder including patients with dominant nociceptive (e.g., myofascial low back pain), neuropathic (e.g., lumbar radiculopathy), and central sensitization pain. In order to select an effective and preferably also efficient treatment in daily clinical practice, LBP patients should be classified clinically as either predominantly nociceptive, neuropathic, or central sensitization pain. To explain how clinicians can differentiate between nociceptive, neuropathic, and central sensitization pain in patients with LBP. Narrative review and expert opinion Universities, university hospitals and private practices Recently, a clinical method for the classification of central sensitization pain versus neuropathic and nociceptive pain was developed. It is based on a body of evidence of original research papers and expert opinion of 18 pain experts from 7 different countries. Here we apply this classification algorithm to the LBP population. The first step ...

Pain physician

A growing body of research has demonstrated that impaired central pain modulation or central sens... more A growing body of research has demonstrated that impaired central pain modulation or central sensitization (CS) is a crucial mechanism for the development of persistent pain in chronic whiplash-associated disorders (WAD) and fibromyalgia (FM) patients. Furthermore, there is increasing evidence for cognitive dysfunctions among these patients. In addition, chronic WAD and FM patients often report problems with health-related quality of life (QoL). Yet, there is limited research concerning the interrelations between cognitive performance, indices of CS, and health-related QoL in these patients. (1) Examining the presence of cognitive impairment, CS, and limitations on health-related QoL in patients with chronic WAD and FM compared to healthy controls. (2) Examining interrelations between performance-based cognitive functioning, CS, and self-reported health-related QoL in these 3 study groups. A case-control study was conducted. The present study took place at the University Hospital Br...

Pain physician

In addition to the frequently reported pain comp laints, performance-based cognitive capabilities... more In addition to the frequently reported pain comp laints, 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. 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. Observational study. The present study took place at the Vrije Universiteit Brussel and the University of Antwerp. 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 attentio...

Journal of rehabilitation research and development, 2013

Pain physician

Although enhanced temporal summation (TS) and conditioned pain modulation (CPM), as characteristi... more 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. 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. Double-blind randomized controlled trial with cross-over design. 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 (CP...

Pain physician

Until now, there is no firm evidence for conservative therapy in patients with chronic Whiplash A... more Until now, there is no firm evidence for conservative therapy in patients with chronic Whiplash Associated Disorders (WAD). While chronic WAD is a biopsychosocial problem, education may be an essential part in the treatment and the prevention of chronic WAD. However, it is still unclear which type of educative intervention has already been used in WAD patients and how effective such interventions are. This systematic literature study aimed at providing an overview of the literature regarding the currently existing educative treatments for patients with whiplash or WAD and their evidence. Systematic review of the literature. A systematic literature search was conducted in the following databases: Pubmed, Springerlink, and Web of Science using different keyword combinations. We included randomized controlled clinical trials (RCT) that encompass the effectiveness of education for patients with WAD. The included articles were evaluated on their methodological quality. Ten RCT's of m...

In vivo (Athens, Greece)

We examined whether activation of serotonergic descending pathways improves pain inhibition durin... more We examined whether activation of serotonergic descending pathways improves pain inhibition during exercise in patients with chronic fatigue syndrome (CFS) and comorbid fibromyalgia (FM) in comparison with rheumatoid arthritis (RA) and sedentary, healthy controls in a double-blind randomized controlled trial with cross-over design. Three female CFS/FM patients, one female RA patient and two healthy women were randomly allocated to the experimental group (2 ml of citalopram intravenously) or the placebo group (2 ml of 0.9% NaCl intravenously). Participants performed a submaximal exercise protocol, preceded and followed by an assessment of endogenous pain inhibition. Seven days later, groups were crossed over. Significant side-effects were observed in all, but one participant immediately after intravenous administration of citalopram. One CFS/FM patient withdrew because of severe post-exertional malaise. It was decided that proceeding with the study would be unethical. No conclusion c...

Pain Practice, 2014

Temporal summation (TS) of pain, conditioned pain modulation (CPM), and exercise-induced analgesi... more 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. 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. Patients with rheumatoid arthritis showed decreased TS after exercise, both after paracetamol and placebo (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 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. 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.

Expert Opinion on Pharmacotherapy, 2014

Exercise immunology review, 2014

An increasing number of studies have examined how the immune system of patients with Chronic Fati... more 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 delaye...

Disability and Rehabilitation, 2014

Abstract Purpose: Unrefreshing sleep and lowered physical activity are commonly observed in chron... more 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.

Clinical Neurology and Neurosurgery, 2014

Delayed recovery of muscle function following exercise has been demonstrated in the lower limbs o... more Delayed recovery of muscle function following exercise has been demonstrated in the lower limbs of patients with multiple sclerosis (MS). However, studies examining this in the upper limbs are currently lacking. This study compared physical activity level (PAL) and recovery of upper limb muscle function following exercise between MS patients and healthy inactive controls. Furthermore, the relationship between PAL and muscle recovery was examined. PAL of 19 MS patients and 32 controls was measured using an accelerometer for 7 consecutive days. Afterwards, recovery of muscle function was assessed by performing a fatiguing upper limb exercise test with subsequent recovery measures. Muscle recovery of the upper limb muscles was similar in both groups. Average activity counts were significantly lower in MS patients than in the control group. MS patients spent significantly more time being sedentary and less time on activities of moderate intensity compared with the control group. No significant correlation between PAL and recovery of muscle function was found in MS patients. Recovery of upper limb muscle function following exercise is normal in MS patients. MS patients are less physically active than healthy inactive controls. PAL and recovery of upper limb muscle function appear unrelated in MS patients.

Clinical Rheumatology, 2014

Physical Therapy, 2014

Both good physical and cognitive functioning have a positive influence on the execution of activi... more 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. 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. A case-control design was used. 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. 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. The cross-sectional nature of this study does not allow for inferences of causation. 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.

Neuroscience Letters, 2011

Methods: The brain signatures of CFS screened patients (n = 30) admitted to a U.K.-based clinic w... more Methods: The brain signatures of CFS screened patients (n = 30) admitted to a U.K.-based clinic were assessed using a full-head 19 channel Quantitative EEG (electroencephalography) during 5 min of eyes open/closed at rest, and while performing a 20 min Visual Continuous Performance Task (VCPT). Following spectral and topographical analysis the data was compared to the Russian Academy of Sciences Human Brain Institute (HBI) normative database for statistically significant differences. In addition, associations between the data and symptom severity scales were also investigated.

Journal of Rehabilitation Research and Development, 2013

Limited scientific evidence suggests that physical activity is directly related to cognitive perf... more 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.

Journal of Internal Medicine, 2013

ABSTRACT In this issue of the Journal of Internal Medicine, Lewis and colleagues [1] provide comp... more ABSTRACT In this issue of the Journal of Internal Medicine, Lewis and colleagues [1] provide compelling data for a novel subgroup within the chronic fatigue syndrome (CFS) population. They show that approximately 13% (24/179) of CFS patients have postural orthostatic tachycardia syndrome (POTS), a form of dysautonomia implying that when patients change their body position from supine to upright, their heart rate will increase abnormally (tachycardia). POTS is associated with several symptoms often seen in CFS patients: fatigue, lightheadedness, dizziness, neurocognitive deficits and exercise intolerance. Importantly, this was a confirmatory study of a previously published pilot study that found a prevalence rate for POTS of 29% in a smaller sample (n=63) of CFS patients [2]. Another significant finding is the differences in fatigue severity, depressive thoughts, and daytime hypersomnolence between CFS patients with and without POTS, providing evidence for the clinical importance of POTS in CFS. © 2013 The Association for the Publication of the Journal of Internal Medicine.