Reduced pressure pain thresholds in response to exercise in chronic fatigue syndrome but not in chronic low back pain: an experimental study

Objective The aims of this study were to examine (i) base line pressure pain thresholds in patients with chronic fatigue syndrome and those with chronic low back pain compared with healthy subjects, (ii) the change in mean pain threshold in response to exercise, and (iii) associations with exercise induced increase in nitric oxide Participants Twenty six patients with chronic fatigue syndrome suffering of chronic pain, 21 patients with chronic low back pain and 31 healthy subjects Methods Participants underwent a submaximal aerobic exercise protocol on a bicycle ergometer, preceded and followed by venous blood sampling (nitric oxide) and algometry (hand arm calf low back) Results Patients with chronic fatigue syndrome presented overall lower pain thresholds compared with healthy sub jects and patients with chronic low back pain (p<0 05) No significant differences were found between healthy subjects and patients with chronic low back pain After submaximal aerobic exercise, mean pain thresholds decreased in patients with chronic fatigue syndrome and increased in the others (p<0 01) At baseline nitric oxide levels were significantly higher in the chronic low back pain group After controlling for body mass index no significant differences were seen be tween the groups at baseline or in response to exercise Nitric oxide was not related to pain thresholds in either group Conclusion The results suggest hyperalgesia and abnormal central pain processing during submaximal aerobic exercise in chronic fatigue syndrome, but not in chronic low back pain Nitric oxide appeared to be unrelated to pain processin

Can pacing self-management alter physical behaviour and symptom severity in chronic fatigue syndrome? : a case series

Given the lack of evidence in support of pacing self-management for patients with chronic fatigue syndrome (CFS), we examined whether physical behavior and health status of patients with CFS Would improve in response to a pacing self-management program. We performed an observational study of pacing self-management in seven CFS patients using a single-case study design. Stages A1 and A2 (7-day assessment periods) of the A1-B-A2 design corresponded to the baseline and posttreatment measurements of physical behavior (real-time activity monitoring) and health status (self-reported measures), respectively. Stage B (3 weeks of treatment) consisted of three individual treatment sessions of pacing self-management. When comparing pre- versus posttreatment data, we found that the patients' ability to perform daily activities and the severity of their symptom complexes were improved (p = 0.043). Concentration difficulties, mood swings, muscle weakness, and intolerance to bright light improved as well. A statistically significant decrease in the mean time spent doing light activity (<3 metabolic equivalents) was observed, but a change in the way physical activity was spread throughout the day was not. We found that 3 weeks of pacing self-management was accompanied by a modest improvement in symptom severity and daily functioning. The outcome of the present study calls for a randomized controlled clinical trial to examine the effectiveness of pacing self-management for people with CFS

Influence of shoulder pain on muscle function: implications for the assessment and therapy of shoulder disorders

Shoulder pain is often a challenging clinical phenomenon because of the potential mismatch between pathology and the perception of pain. Current evidence clearly emphasizes an incomplete understanding of the nature of shoulder pain. Indeed, the effective diagnosis and treatment of shoulder pain should not only rely upon a detailed knowledge of the peripheral pathologies that may be present in the shoulder, but also on current knowledge of pain neurophysiology. To assess and treat shoulder pain, a comprehensive understanding of the way in which pain is processed is essential. This review reflects modern pain neurophysiology to the shoulder and aims to answer the following questions: why does my shoulder hurt? What is the impact of shoulder pain on muscle function? What are the implications for the clinical examination of the shoulder? And finally, what are the clinical implications for therapy? Despite the increasing amount of research in this area, an in-depth understanding of the bidirectional nociception-motor interaction is still far from being achieved. Many questions remain, especially related to the treatment of nociception-motor interactions

Can exercise limits prevent post-exertional malaise in chronic fatigue syndrome? An uncontrolled clinical trial.

&lt;b&gt;Objective&lt;/b&gt;: It was hypothesized that the use of exercise limits prevents symptom increases and worsening of their health status following a walking exercise in people with Chronic Fatigue Syndrome (CFS). &lt;b&gt;Design&lt;/b&gt;: An uncontrolled clinical trial (semi-experimental design). &lt;b&gt;Setting&lt;/b&gt;: Outpatient clinic of a university department. &lt;b&gt;Subjects&lt;/b&gt;: 24 patients with CFS. &lt;b&gt;Interventions&lt;/b&gt;: Subjects undertook a walking test with the two concurrent exercise limits. Each subject walked at an &lt;i&gt;intensity&lt;/i&gt; where the maximum heart rate was determined by heart rate corresponding to the respiratory exchange ratio =1.0 derived from a previous sub-maximal exercise test and for a duration calculated from how long each patient felt they were able to walk. &lt;b&gt;Main outcome measures&lt;/b&gt;: The Short Form 36 Health Survey or SF-36, the CFS Symptom List, and the CFS-Activities and Participation Questionnaire were filled in prior to, immediately and 24 hours post-exercise. &lt;b&gt;Results&lt;/b&gt;: The fatigue increase observed immediately post-exercise (p=0.006) returned to pre-exercise levels 24 hours post-exercise. The increase in pain observed immediately post-exercise was retained at 24 hours post-exercise (p=0.03). Fourteen of 24 subjects experienced a clinically meaningful change in bodily pain (change of SF-36 bodily pain score ³10). Six of 24 participants indicated that the exercise bout had slightly worsened their health status, and 2 of 24 had a clinically meaningful decrease in vitality (change of SF-36 vitality score ³20). There was no change in activity limitations/participation restrictions. &lt;b&gt;Conclusion&lt;/b&gt;: It was shown that the use of exercise limits (limiting both the intensity and duration of exercise) prevents important health status changes following a walking exercise in people with CFS, but was unable to prevent short-term symptom increases

Cognitive performance is related to central sensitization and health-related quality of life in patients with chronic whiplash-associated disorders and fibromyalgia

Background: 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. Objectives: (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. Study Design: A case-control study was conducted. Setting: The present study took place at the University Hospital Brussels, the University of Brussels, and the University of Antwerp. Methods: Fifty-nine patients (16 chronic WAD patients, 21 FM patients, and 22 pain-free volunteers) filled out the Short Form 36 item Health Survey (SF-36), a self-reported psychosocial questionnaire, to assess health-related QoL. Next, they were subjected to various pain measurements (pressure hyperalgesia, deep-tissue hyperalgesia, temporal summation [TS], and conditioned pain modulation [CPM]). Finally, participants completed a battery of performance-based cognitive tests (Stroop task, psychomotor vigilance task [PVT], and operation span task [OSPAN]). Results: Significant cognitive impairment, bottom-up sensitization, and decreased health-related QoL were demonstrated in patients with chronic WAD and FM compared to healthy controls (P < 0.017). CPM was comparable between the 3 groups. Cognitive performance was significantly related to central pain modulation (deep-tissue hyperalgesia, TS, CPM) as well as to self-reported health-related QoL (P < 0.05). Decreased cognitive performance was related to deficient central pain modulation in healthy controls. Further, significant correlations between decreased cognitive performance and reduced health-related QoL were revealed among all study groups. Additionally, FM patients showed correlations between cognitive impairment and increased health-related QoL. Remarkably, impaired selective attention and working memory were related to less TS, whereas impaired sustained attention was correlated with dysfunctional CPM in FM patients. Limitations: Based on the current cross-sectional study no firm conclusions can be drawn on the causality of the relations. Conclusion: In conclusion, this paper has demonstrated significant cognitive deficits, signs of CS, and reduced health-related QoL in chronic WAD and FM patients compared to healthy individuals. Significant relations between cognitive performance and CS as well as health-related QoL were demonstrated. These results provide preliminary evidence for the clinical importance of objectively measured cognitive deficits in patients with chronic WAD and FM

Author Response

In conclusion, it is key for physical therapists to acknowledge that an important subgroup of patients with OA develop hyperexcitability of the central nervous system and that CS plays a crucial role in the pain reported by these patients. Recent studies published in wellrespected journals support our argument

Effects of stress and relaxation on central pain modulation in chronic whiplash and fibromyalgia patients compared to healthy controls

Background: Compelling evidence has demonstrated that impaired central pain modulation contributes to persistent pain in patients with chronic whiplash associated disorders (WAD) and fibromyalgia (FM). However, there is limited research concerning the influence of stress and relaxation on central pain modulation in patients with chronic WAD and FM. Objectives: The present study aims to investigate the effects of acute cognitive stress and relaxation on central pain modulation in chronic WAD and FM patients compared to healthy individuals. Study Design: A randomized crossover design was employed. Setting: The present study took place at the University of Brussels, the University Hospital Brussels, and the University of Antwerp. Methods: Fifty-nine participants (16 chronic WAD patients, 21 FM, 22 pain-free controls) were enrolled and subjected to various pain measurements. Temporal summation (TS) of pain and conditioned pain modulation (CPM) were evaluated. Subsequently, participants were randomly allocated to either a group that received progressive relaxation therapy or a group that performed a battery of cognitive tests (= cognitive stressor). Afterwards, all pain measurements were repeated. One week later participant groups were switched. Results: A significant difference was found between the groups in the change in TS in response to relaxation (P = 0.008) and cognitive stress (P = 0.003). TS decreased in response to relaxation and cognitive stress in chronic WAD patients and controls. In contrast, TS increased after both interventions in FM patients. CPM efficacy decreased in all 3 groups in response to relaxation (P = 0.002) and cognitive stress (P = 0.001). Limitations: The obtained results only apply for a single session of muscle relaxation therapy and cognitive stress, whereby no conclusions can be made for effects on pain perception and modulation of chronic cognitive stress and long-term relaxation therapies. Conclusions: A single relaxation session as well as cognitive stress may have negative acute effects on pain modulation in patients with FM, while cognitive stress and relaxation did not worsen bottom-up sensitization in chronic WAD patients and healthy persons. However, endogenous pain inhibition, assessed using a CPM paradigm, worsened in chronic WAD and FM patients, as well as in healthy people following both interventions

Dysfunctional endogenous analgesia during exercise in patients with chronic pain : to exercise or not to exercise?

Background: Exercise is an effective treatment for various chronic pain disorders, including fibromyalgia, chronic neck pain, osteoarthritis, rheumatoid arthritis, and chronic low back pain. Although the clinical benefits of exercise therapy in these populations are well established (i.e. evidence based), it is currently unclear whether exercise has positive effects on the processes involved in chronic pain (e.g. central pain modulation). Objectives: Reviewing the available evidence addressing the effects of exercise on central pain modulation in patients with chronic pain. Methods: Narrative review. Results: Exercise activates endogenous analgesia in healthy individuals. The increased pain threshold following exercise is due to the release of endogenous opioids and activation of (supra)spinal nociceptive inhibitory mechanisms orchestrated by the brain. Exercise triggers the release of β-endorphins from the pituitary (peripherally) and the hypothalamus (centrally), which in turn enables analgesic effects by activating μ-opioid receptors peripherally and centrally, respectively. The hypothalamus, through its projections on the periaqueductal grey, has the capacity to activate descending nociceptive inhibitory mechanisms. However, several groups have shown dysfunctioning of endogenous analgesia in response to exercise in patients with chronic pain. Muscle contractions activate generalized endogenous analgesia in healthy, pain-free humans and patients with either osteoarthritis or rheumatoid arthritis, but result in increased generalised pain sensitivity in fibromyalgia patients. In patients having local muscular pain (e.g. shoulder myalgia), exercising non-painful muscles activates generalized endogenous analgesia. However, exercising painful muscles does not change pain sensitivity either in the exercising muscle or at distant locations. Limitations: The reviewed studies examined acute effects of exercise rather than long-term effects of exercise therapy. Conclusions: A dysfunctional response of patients with chronic pain and aberrations in central pain modulation to exercise has been shown, indicating that exercise therapy should be individually tailored with emphasis on prevention of symptom flares. The paper discusses the translation of these findings to rehabilitation practice together with future research avenues