Effect of perioperative pain neuroscience education in people undergoing surgery for lumbar radiculopathy: a multicentre randomised controlled trial.

BACKGROUND: Perioperative education should be improved to decrease unfavourable outcomes after lumbar surgery. This trial aimed to compare effectiveness in terms of pain, quality of life, pain cognition, surgical experience, healthcare use, work resumption, and cost-effectiveness of perioperative pain neuroscience education (PPNE) vs traditional biomedical education (perioperative biomedical education [PBE]) in people undergoing surgery for lumbar radiculopathy. METHODS: In this multicentre RCT (ClinicalTrials.gov: NCT02630732), patients undergoing surgery for lumbar radiculopathy in three Belgian hospitals were randomised to receive PPNE or PBE. Both groups received one preoperative and one postoperative one-to-one education session and a booklet (balanced interventions), with an essentially different content (PPNE: biopsychosocial; PBE: biomedical). Pain was the primary outcome (Visual Analogue Scales+quantitative sensory testing). Assessments were at 3 days, 6 weeks, and 6 and 12 months after surgery. RESULTS: Between March 2016 and April 2020, participants were randomly assigned to PPNE (n=58) or PBE (n=62). At 12 months, PPNE did not lead to significantly better pain outcomes, but it did result in more favourable 36-item Short Form Health Survey physical component (additional increase: 46.94; 95% confidence interval [CI]: 14.16-79.73; medium effect), Tampa Scale of Kinesiophobia (additional decrease: 3.15; 95% CI: 0.25-6.04; small effect), and Pain Catastrophising Scale (additional decrease: 6.18; 95% CI: 1.97-10.39; medium effect) scores. Females of the PPNE group showed higher probability for work resumption (95% vs 60% in the PBE group). PPNE was cost-effective compared with PBE (incremental costs: €-2732; incremental quality-adjusted life years: 0.012). CONCLUSIONS: Perioperative pain neuroscience education showed superior clinical and cost-effectiveness than perioperative biomedical education in people undergoing surgery for lumbar radiculopathy. CLINICAL TRIAL REGISTRATION: NCT02630732.

Experimental Pain Measurements Do Not Relate to Pain Intensity and Pain Cognitions in People Scheduled for Surgery for Lumbar Radiculopathy.

OBJECTIVE: The present cross-sectional study aims to unravel associations of pain intensity and cognitions with quantitative sensory testing in people scheduled for surgery for lumbar radiculopathy. Additionally, insight will be provided into the presence of dysfunctional nociceptive processing and maladaptive pain cognitions in this population. DESIGN: Cross-sectional study. SETTING: Data from three hospitals in Belgium. SUBJECTS: The final sample comprised 120 participants with lumbar radiculopathy scheduled for surgery, included between March 2016 and April 2019. METHODS: Self-reported pain intensity was assessed on a visual analog scale, and pain cognitions were assessed with self-reported questionnaires (Pain Catastrophizing Scale, Tampa Scale for Kinesiophobia, and Pain Vigilance and Awareness Questionnaire). Quantitative sensory testing (detection thresholds, pain thresholds, temporal summation, and conditioned pain modulation) was evaluated, as well. RESULTS: Evidence was found for the presence of an impaired inhibitory response to nociceptive stimuli and maladaptive pain cognitions in this population. Kinesiophobia was found to be present to a maladaptive degree in the majority of the patients (n = 106 [88%]). Significant, but weak, associations between electrical pain thresholds at the sural nerves and leg pain intensity (sural nerve symptomatic side: r = -0.23; P = 0.01; non-symptomatic side: r = -0.22; P = 0.02) and kinesiophobia levels (sural nerve non-symptomatic side: r = -0.26; P = 0.006) were identified. CONCLUSIONS: Electrical detection thresholds and correlates for endogenous nociceptive facilitation and inhibition were not found to be related to any of the pain cognitions or to pain intensity in people scheduled to undergo surgery for lumbar radiculopathy.

Genetic and epigenetic regulation of Catechol-O-methyltransferase in relation to inflammation in chronic fatigue syndrome and Fibromyalgia.

BACKGROUND: Catechol-O-methyltransferase (COMT) has been shown to influence clinical pain, descending modulation, and exercise-induced symptom worsening. COMT regulates nociceptive processing and inflammation, key pathophysiological features of Chronic Fatigue Syndrome and Fibromyalgia (CFS/FM). We aimed to determine the interactions between genetic and epigenetic mechanisms regulating COMT and its influence on inflammatory markers and symptoms in patients with CFS/FM. METHODS: A case-control study with repeated-measures design was used to reduce the chance of false positive and increase the power of our findings. Fifty-four participants (28 patients with CFS/FM and 26 controls) were assessed twice within 4 days. The assessment included clinical questionnaires, neurophysiological assessment (pain thresholds, temporal summation, and conditioned pain modulation), and blood withdrawal in order to assess rs4818, rs4633, and rs4680 COMT polymorphisms and perform haplotype estimation, DNA methylation in the COMT gene (both MB-COMT and S-COMT promoters), and cytokine expression (TNF-α, IFN-γ, IL-6, and TGF-ß). RESULTS: COMT haplotypes were associated with DNA methylation in the S-COMT promoter, TGF-ß expression, and symptoms. However, this was not specific for one condition. Significant between-group differences were found for increased DNA methylation in the MB-COMT promoter and decreased IFN-γ expression in patients. DISCUSSION: Our results are consistent with basic and clinical research, providing interesting insights into genetic-epigenetic regulatory mechanisms. MB-COMT DNA methylation might be an independent factor contributing to the pathophysiology of CFS/FM. Further research on DNA methylation in complex conditions such as CFS/FM is warranted. We recommend future research to employ a repeated-measure design to control for biomarkers variability and within-subject changes.

The Effect of a Pain Educational Video Upon Child Pain-Related Memory and the Moderating Role of Parental Pain- and Non-Pain-Attending Verbalizations: An Experimental Lab-Based Study.

OBJECTIVES: Early memories of pain contribute to fear and may underlie the maintenance and development of chronic pain into adulthood. Accordingly, understanding determinants that may impact children's pain memory development is key. This study examined (a) the effect of a brief engaging pain educational video in healthy children before undergoing an experimental pain task upon children's recalled pain intensity and pain-related fear and (b) the moderating role of parental pain- and non-pain-attending verbalizations before and after the pain task. METHODS: Seventy-seven children (8-15 years old) participated in an experimental heat pain task, including actual heat pain stimuli delivered through a thermode on their forearm. Children were randomized to the experimental group (i.e., watching a pain educational video) or the control group (i.e., no video). Children's recalled pain intensity and pain-related fear were elicited 2 weeks later. RESULTS: Findings showed that recalled pain intensity (but not recalled pain-related fear) of children who watched the pain educational video was significantly lower compared to the control group (p = .028). Further, parental pain-attending verbalizations before the pain task moderated the impact of the video upon children's recalled pain intensity (p = .038). Specifically, children in the control group, but not the experimental group, whose parents used less pain-attending verbalizations recalled higher pain intensity, whereas children whose parents used more pain-attending verbalizations recalled lower pain intensity. CONCLUSIONS: As children's pain memories have important implications for pain assessment, treatment, and health across the lifespan, these findings might have important implications for the prevention of development or maintenance of maladaptive pain-related outcomes.

Health-related quality of life deviations from population norms in patients with lumbar radiculopathy: associations with pain, pain cognitions, and endogenous nociceptive modulation.

PURPOSE: The primary goal of this study was to compare the health-related quality of life (HRQoL) of people with lumbar radiculopathy to age- and sex-adjusted population norms. Additionally, it aimed to explore the associations between the HRQoL difference scores and measures related to pain cognitions, pain intensity, and endogenous nociceptive modulation. METHODS: Using answers from the Short Form 36-item Health Survey and UK population norms, SF-6D difference scores were calculated. A one-sample t test was used to assess the SF-6D difference scores. Univariate and multivariate regression analyses were used to assess the associations between SF-6D difference scores and pain intensity [Visual Analogue Scale (VAS) for back and leg pain], pain cognitions [Pain Catastrophizing Scale (PCS), Tampa Scale for Kinesiophobia (TSK), Pain Vigilance and Awareness Questionnaire (PVAQ)], and correlates for endogenous nociceptive modulation using quantitative sensory testing. RESULTS: One hundred and twenty people with lumbar radiculopathy scheduled for surgery were included in this study. The mean SF-6D difference score of - 0.26 [SD = 0.09] was found to be significantly less than 0 [95%CI: - 0.27 to - 0.24]. Univariate analyses showed a significant influence from PCS, TSK, and PVAQ on the SF-6D difference scores. The final multivariate regression model included PCS and PVAQ, with only PCS maintaining a statistically significant regression coefficient [b = - 0.002; 95% CI: - 0.004 to - 0.001]. CONCLUSION: People diagnosed with lumbar radiculopathy report significantly lower HRQoL scores when compared with age- and sex-adjusted UK norm values. Even though all examined pain cognitions were found to have a significant association, pain catastrophizing showed the most significant relation to the SF-6D difference scores. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov Identifier No. NCT02630732. Date of registration: November 25, 2015.

The Impact of Parental Presence on Their Children During Painful Medical Procedures: A Systematic Review.

OBJECTIVE: Whether parental presence during their children's painful medical procedures is advantageous with regard to children's pain-related outcomes is questionable. Research on this topic is equivocal, and additional questions, such as whether levels of parental involvement may play a role as well, remain to be addressed. The purpose of this systematic review is to summarize and critically appraise the literature on the impact of parental presence vs absence during their children's painful medical procedures on the child's pain-related outcomes. METHODS: The review protocol was registered on Prospero (ID CRD42018116614). A systematic search in PubMed, Web of Science, and PsycArticles resulted in 22 eligible studies incorporating 2,157 participants. Studies were considered eligible if they included children (≤18 years old) undergoing a painful medical procedure and compared parental presence and/or involvement with parental absence during the procedure. RESULTS: The children's pain-related outcomes included self-reported pain intensity, self-reported fear, anxiety and distress, observed pain-related behavior, and physiological parameters. Overall, evidence points in the direction of beneficial effects of parental presence vs absence with regard to children's self-reported pain intensity and physiological parameters, whereas mixed findings were recorded for children's self-reported fears, anxiety and distress, and observed pain-related behaviors. CONCLUSIONS: To provide clear recommendations on how to involve the parent during the procedure, as well as for which type of children and parents parental presence has the best effects, further research is needed, as indicated in this review.

Convergent Validity of the Central Sensitization Inventory in Chronic Whiplash-Associated Disorders; Associations with Quantitative Sensory Testing, Pain Intensity, Fatigue, and Psychosocial Factors.

OBJECTIVE: Central sensitization is present in different pain conditions, including chronic whiplash-associated disorders. In the absence of a gold standard method of assessment to determine the presence of central sensitization, quantitative sensory testing is currently understood as an optimal proxy. Laboratory sensory testing is, however, not feasible in clinical practice, and the Central Sensitization Inventory was developed as an alternative. The aim of the current study was to evaluate the convergent validity of the Central Sensitization Inventory in chronic whiplash-associated patients by determining the association between the Central Sensitization Inventory and quantitative sensory testing, pain intensity, fatigue, and psychosocial factors. METHODS: A total of 125 chronic whiplash-associated patients completed multiple questionnaires and were subjected to pressure pain thresholds and temporal summation. RESULTS: . The Central Sensitization Inventory showed a strong association with constructs of general psychopathology, anxiety, distress, depression, and somatization in chronic whiplash-associated disorders. Moderate correlations were found with fatigue and intrusive and avoidant phenomena after a variety of traumatic events. No significant association was found between the Central Sensitization Inventory and pressure pain thresholds and temporal summation, nor between the Central Sensitization Inventory and other pain measurements. CONCLUSIONS: Overall, we found that the Central Sensitization Inventory is better in identifying the psychosocial factors related to central sensitization in chronic whiplash-associated disorders than the central nervous system adaptations. Thus, the convergent validity of the Central Sensitization Inventory appears to be only partially present in chronic whiplash-associated disorders.

Electrical (Pain) Thresholds and Conditioned Pain Modulation in Patients with Low Back-Related Leg Pain and Patients with Failed Back Surgery Syndrome: A Cross-Sectional Pilot Study.

OBJECTIVE: When evaluating sensory dysfunctions and pain mechanisms in patients with low back pain (LBP), a specific subgroup of patients with radicular symptoms is often excluded. Comparative studies that evaluate sensory sensitivity in patients with a dominant nociceptive and neuropathic pain component are rarely performed. Therefore, the goal of this study was to examine differences in electrical thresholds and conditioned pain modulation (CPM) between patients with low back-related leg pain (LBRLP) and patients with failed back surgery syndrome (FBSS). DESIGN: Cross-sectional study. SETTING: University Hospital Brussels. SUBJECTS: Twenty-one patients with LBRLP and 21 patients with FBSS were included. METHODS: Electrical detection thresholds (EDTs), electrical pain thresholds (EPTs), and CPM were evaluated on the symptomatic and nonsymptomatic sides. Within- and between-group differences were evaluated for all parameters. RESULTS: No between-group differences were found for EDT and EPT at both sides. On the nonsymptomatic side, a significantly lower CPM effect was found in the FBSS group (P = 0.04). The only significant within-group difference was an increased EDT at the symptomatic side in patients with FBSS (P = 0.01). CONCLUSIONS: LBP patients with a primary neuropathic pain component revealed altered detection sensitivity at the symptomatic side, without severe indications for altered nociceptive processing, compared with LBP patients without a dominant neuropathic pain component. Endogenous modulation is functioning in LBP patients, although it is possible that it might only be functioning partially in patients with a dominant neuropathic pain component.

Electroencephalography During Nociceptive Stimulation in Chronic Pain Patients: A Systematic Review.

BACKGROUND: With its high temporal resolution, electroencephalography (EEG), a technique that records electrical activity of cortical neuronal cells, is a potentially suitable technique to investigate human somatosensory processing. By using EEG, the processing of (nociceptive) stimuli can be investigated, along with the functionality of the nociceptive pathway. Therefore, it can be applied in chronic pain patients to objectify whether changes have occurred in nociceptive processing. Typically, so-called event-related potential (ERP) recordings are used, where EEG signals are recorded in response to specific stimuli and characterized by latency and amplitude. OBJECTIVE: To summarize whether differences in somatosensory processing occur between chronic pain patients and healthy controls, measured with ERPs, and determine whether this response is related to the subjective pain intensity. DESIGN: Systematic review. SETTING AND METHODS: PubMed, Web of Science, and Embase were consulted, and 18 case-control studies were finally included. SUBJECTS: The chronic pain patients suffered from tension-type headache, back pain, migraine, fibromyalgia, carpal tunnel syndrome, prostatitis, or complex regional pain syndrome. RESULTS: Chronic neuropathic pain patients showed increased latencies of the N2 and P2 components, along with a decreased amplitude of the N2-P2 complex, which was also obtained in FM patients with small fiber dysfunction. The latter also showed a decreased amplitude of the N2-P3 and N1-P1 complex. For the other chronic pain patients, the latencies and the amplitudes of the ERP components did not seem to differ from healthy controls. One paper indicated that the N2-P3 peak-to-peak amplitude correlates with the subjective experience of the stimulus. CONCLUSIONS: Differences in ERPs with healthy controls can mostly be found in chronic pain populations that suffer from neuropathic pain or where fiber dysfunction is present. In chronic pain populations with other etiological mechanisms, limited differences were found or agreed upon across studies.

The Association of Psychosocial Factors and Exercise-Induced Hypoalgesia in Healthy People and People With Musculoskeletal Pain: A Systematic Review.

BACKGROUND: Exercise, a cornerstone in current treatments for people with musculoskeletal pain, elicits a phenomenon called exercise-induced hypoalgesia (EIH), which may result in reduced pain intensity and/or increased pain thresholds. However, EIH can be impaired in patients with musculoskeletal pain, and psychosocial factors may play a mediating role in EIH. OBJECTIVE: The aim of this study was to systematically review the scientific literature regarding the association between psychosocial factors and EIH in healthy people and people with musculoskeletal pain. METHODS: An extensive search in databases including Medline Ovid, Embase, Web of Science, PsycINFO Ovid, and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) EBSCOhost was carried out. Two reviewers independently carried out study selection, data extraction, and critical appraisal. Included studies analyzed the association or effect of psychosocial factors on EIH in adults with or without musculoskeletal pain. RESULTS: Nine cross-sectional studies were included, 6 involving healthy people and 4 involving people with musculoskeletal pain; 1 study included both. Overall risk of bias was high. Different types of exercise bouts, psychosocial factors, and/or outcome measures were used across studies. In healthy people and people with musculoskeletal pain, most studies did not find an association between psychosocial factors and EIH. However, 1 study involving musculoskeletal pain and 2 studies with healthy people did find a significant association. CONCLUSION: Due to poor quality and heterogeneity between studies, no conclusions can be drawn regarding whether psychosocial factors are associated with EIH or not. This review includes recommendations and directions for further research to investigate the role of psychosocial factors on EIH.

When Environment Meets Genetics: A Clinical Review of the Epigenetics of Pain, Psychological Factors, and Physical Activity.

Epigenetic mechanisms represent a link between the environment and gene function. Recent research shows how early life stress, inflammation, and physical activity can influence gene expression through epigenetic mechanisms. Epigenetic changes-such as DNA methylation and microRNA interference-can be measured in humans and might soon become important biological markers. Epigenetic marks can accompany clinical assessment to measure the effectiveness of various interventions, such as exercise therapy. In addition, epigenetics is improving the understanding of important underlying mechanisms related to the central nervous system, the opioidergic system, and stress responses. Epigenetics is closing a gap in our explanatory abilities and should be implemented to broaden the field of rehabilitation sciences, promote a mechanism-based clinical reasoning, and develop new treatments. In the present review, we focused on epigenetic mechanisms related to pain, psychological factors (such as fear and anxiety), and physical activity, translating relevant findings from these 3 different, yet related, areas of cardinal importance for clinicians.

Hyperexcitability of the Central Nervous System in Children with Chronic Pain: A Systematic Review.

Objective: Hyperexcitability of the central nervous system plays an important role in the development and maintenance of chronic pain in adults. This knowledge has led to improved treatment strategies within this population. In children, however, research on the presence of central hyperexcitability is scarce. To further investigate this topic in children with chronic pain, there is a need for a clear literature overview. Design: Systematic review. Methods: The literature search was performed using the electronic databases PubMed and Web of Science. An article was considered eligible if it included children (age two to 12 years) diagnosed with chronic pain. Articles had to report original research outcomes related to central hyperexcitability, and a comparison with a healthy control group was necessary. Characteristics of the study sample, the assessment, and conclusions regarding central hyperexcitability were extracted from each included article. Results: Twelve case-control studies were included with moderate to good methodological quality (510 children with chronic pain and 670 healthy controls). After summarizing the articles' results on indices of central hyperexcitability, we concluded that secondary hyperalgesia might be present in children with recurrent abdominal pain, juvenile fibromyalgia, and juvenile idiopathic arthritis. Preliminary evidence exists for altered cortical nociceptive processing in children with migraine and recurrent abdominal pain. Conclusion: Based on the results of this review, central hyperexcitability might be present in in several pediatric chronic pain conditions. Further research on other manifestations of central hyperexcitability (e.g., bottom-up and top-down mechanisms and nociceptive brain changes) is necessary to provide firm evidence about its presence in children with chronic pain.

Association Between Symptoms of Central Sensitization and Cognitive Behavioral Factors in People With Chronic Nonspecific Low Back Pain: A Cross-sectional Study.

OBJECTIVE: The objective of this cross-sectional study was to analyze the relationship between symptoms of central sensitization (CS) and important cognitive behavioral and psychosocial factors in a sample of patients with chronic nonspecific low back pain. METHODS: Participants with chronic nonspecific low back pain for at least 3 months were included in the study. They completed several questionnaires and a functional test. Pearson's correlation was used to analyze associations between symptoms of CS and pain behavior, functioning, pain, pain catastrophizing, kinesiophobia, and illness perceptions. Additionally, a between-group analysis was performed to compare patients with and without clinically relevant symptoms of CS. RESULTS: Data from 38 participants were analyzed. Significant associations were found between symptoms of CS and all other outcomes, especially current pain (r = 0.510, P = .001), mean pain during the past 7 days (r = 0.505, P = .001), and pain catastrophizing (r = 0.518, P = .001). Patients with clinically relevant symptoms of CS scored significantly worse on all outcomes compared with persons without relevant symptoms of CS, except on functioning (P = .128). CONCLUSIONS: Symptoms of CS were significantly associated with psychosocial and cognitive behavioral factors. Patients exhibiting a clinically relevant degree of symptoms of CS scored significantly worse on most outcomes, compared with the subgroup of the sample with fewer symptoms of CS.

In the spine or in the brain? Recent advances in pain neuroscience applied in the intervention for low back pain.

Conservative, surgical and pharmacological strategies for chronic low back pain (CLBP) management offer at best modest effect sizes in reducing pain and related disability, indicating a need for improvement. Such improvement may be derived from applying contemporary pain neuroscience to the management of CLBP. Current interventions for people with CLBP are often based entirely on a "biomedical" or "psychological" model without consideration of information concerning underlying pain mechanisms and contemporary pain neuroscience. Here we update readers with our current understanding of pain in people with CLBP, showing that CLBP is not limited to spinal impairments, but is also characterised by brain changes, including functional connectivity reorganisation in several brain regions and increased activation in brain regions of the so-called 'pain matrix' (or 'pain connectome'). Indeed, in a subgroup of the CLBP population brain changes associated with the presence of central sensitisation are seen. Understanding the role of these brain changes in CLBP improves our understanding not only of pain symptoms, but also of prevalent CLBP associated comorbidities such as sleep disturbances and fear avoidance behaviour. Applying contemporary pain neuroscience to improve care for people with CLBP includes identifying relevant pain mechanisms to steer intervention, addressing sleep problems and optimising exercise and activity interventions. This approach includes cognitively preparing patients for exercise therapy using (therapeutic) pain neuroscience education, followed by cognition-targeted functional exercise therapy.

Twiddler's Syndrome and Neuromodulation-Devices: A Troubled Marriage.

OBJECTIVE: The occurrence of Twiddler's syndrome in subjects with neurostimulator devices is poorly understood and might be influenced by age, sex, BMI, use of medication or psychologic disorders. METHODS: Two hundred thiry-five patients who received a neuromodulator were included in this retrospective study in a period between 2008 and 2015. The subjects were divided into a group of Twiddler's syndrome patients (TS) and a group of non-Twiddler's patients (NTS). Outcome measures were gender, age at implantation, type of neuromodulation, use of antipsychotics, antidepressants and opioids, the presence of other psychologic disorders and BMI. RESULTS: Both groups differ significantly in age (p = 0.024), weight (p = 0.001) and BMI (p = 0.001). No statistical difference was found in the type of neuromodulation (p = 0.537), gender (p = 0.368), the use of antipsychotics (p = 0.071), antidepressants (p = 0.097), and opioids (p = 1). Forward stepwise logistic regression of all variables showed that age of implementation (p = 0.029), the use of antipsychotics (p = 0.022) and BMI (p = 0.001) were statistically significant for predicting Twiddler's syndrome. CONCLUSION: Twiddler's syndrome is an uncommon complication of neuromodulation implantable devices. Younger age, use of antipsychotics, and high BMI are risk factors that can be used to facilitate rapid diagnosis and treatment.

Effectiveness of a fine motor skills rehabilitation program on upper limb disability, manual dexterity, pinch strength, range of fingers motion, performance in activities of daily living, functional independency, and general self-efficacy in hand osteoarthritis: A randomized clinical trial.

STUDY DESIGN: A randomized clinical trial. INTRODUCTION: Rehabilitation treatments for improving fine motor skills (FMS) in hand osteoarthritis (HOA) have not been well explored yet. PURPOSE OF THE STUDY: To assess the effectiveness of a rehabilitation program on upper limb disability, independence of activities of daily living (ADLs), fine motor abilities, functional independency, and general self-efficacy in older adults with HOA. METHODS: About 45 adults (74-86 years) with HOA were assigned to an experimental group for completing an FMS intervention or a control group receiving conventional occupational therapy. Both interventions were performed 3 times/wk, 45 minutes each session, during 8 weeks. Upper limb disability, performance in ADLs, pinch strength, manual dexterity, range of fingers motion, functional independency, and general self-efficacy were assessed at baseline, immediately after treatment, and after 2 months of follow-up. RESULTS: FMS group showed significant improvements with a small effect size on manual dexterity (P ≤ .034; d ≥ 0.48) and a moderate-high effect on range of index (P ≤ .018; d ≥ 0.58) and thumb (P ≤ .027; d ≥ 0.39) motion. The control group showed a significant worse range of motion over time in some joints at the index (P ≤ .037; d ≥ 0.36) finger and thumb (P ≤ .017; d ≥ 0.55). CONCLUSIONS: A rehabilitation intervention for FMS may improve manual dexterity and range of fingers motion in HOA, but its effects on upper limb disability, performance in ADLs, pinch strength, functionality, and self-efficacy remain uncertain. Specific interventions of the hand are needed to prevent a worsening in range of finger motion. LEVEL OF EVIDENCE: 1b.

Abnormal Pain Response to Visual Feedback During Cervical Movements in Chronic Whiplash: An Experimental Study.

BACKGROUND: Whiplash-associated disorders (WAD) are a debilitating condition. In chronic WAD, sensorimotor incongruence exacerbates symptoms. Sensorimotor incongruence occurs when somatosensory input and predicted motor output are in conflict, which can trigger pain. On the other hand, there is evidence that visual feedback can decrease pain in certain chronic pain conditions. Therefore, the aim of this study was to examine the effect of visual feedback and sensorimotor incongruence on pain thresholds in chronic WAD. METHODS: Sixty-four participants (healthy controls and patients with chronic WAD) were subjected to six experimental conditions. Participants watched correct real-time or modified visual feedback of the neck or hand (without movement as well as during repetitive neck lateroflexion). Sensorimotor incongruence was induced by manipulating visual feedback. Pressure pain thresholds were measured at baseline and during each condition. RESULTS: Marked between-group differences were observed. Visual feedback of the neck-correct or modified-did not influence pain thresholds in chronic WAD. In contrast, healthy controls had significantly higher pain thresholds when provided with the correct or modified visual feedback. When a movement of the neck was added during visual feedback, patients with chronic WAD showed no significant difference in pain thresholds, while an increase in pain thresholds was found in the healthy control group. CONCLUSION: In contrast to the healthy controls, visual feedback and sensorimotor incongruence did not alter pain thresholds in patients with chronic WAD. These findings suggest an abnormal pain response to visual feedback and somatosensory incongruence as well as failing mechanisms of pain inhibition in chronic WAD.

Pain following cancer treatment: Guidelines for the clinical classification of predominant neuropathic, nociceptive and central sensitization pain.

BACKGROUND: In addition to fatigue, pain is the most frequent persistent symptom in cancer survivors. Clear guidelines for both the diagnosis and treatment of pain in cancer survivors are lacking. Classification of pain is important as it may facilitate more specific targeting of treatment. In this paper we present an overview of nociceptive, neuropathic and central sensitization pain following cancer treatment, as well as the rationale, criteria and process for stratifying pain classification. MATERIAL AND METHODS: Recently, a clinical method for classifying any pain as either predominant central sensitization pain, neuropathic or nociceptive pain was developed, based on a large body of research evidence and international expert opinion. We, a team of 15 authors from 13 different centers, four countries and two continents have applied this classification algorithm to the cancer survivor population. RESULTS: The classification of pain following cancer treatment entails two steps: (1) examining the presence of neuropathic pain; and (2) using an algorithm for differentiating predominant nociceptive and central sensitization pain. Step 1 builds on the established criteria for neuropathic pain diagnosis, while Step 2 applies a recently developed clinical method for classifying any pain as either predominant central sensitization pain, neuropathic or nociceptive pain to the cancer survivor population. CONCLUSION: The classification criteria allow identifying central sensitization pain following cancer treatment. The recognition of central sensitization pain in practice is an important development in the integration of pain neuroscience into the clinic, and one that is relevant for people undergoing and following cancer treatment.

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.

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.

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

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.