Analysis of the pain in multiple sclerosis patients

The Assessment of the Prevalence and Disability Severity of Musculoskeletal Pain in Patients With Multiple Sclerosis in Saudi Arabia

Background Multiple sclerosis (MS) is an autoimmune disease of the nervous system that causes chronic demyelination over time and may lead to physical disability. MS-related pain may be musculoskeletal, paroxysmal, or persistently neurogenic in nature. The most common type of pain is musculoskeletal discomfort, which is typically brought on by muscle weakening, stiffness, and generalized imbalance as the condition progresses. Pain often manifests after prolonged immobilization of muscles, tendons, and ligaments. Aim We aimed to evaluate the prevalence and severity of musculoskeletal pain (MSP) among MS patients in Saudi Arabia. Methodology A quantitative cross-sectional study was conducted. Patients with confirmed MS in Saudi Arabia were invited to participate in the study during the duration from April 2022 to May 2022. Data were collected using an electronic collection tool. The study tool was checked to ensure the content validity and clarity of the Arabic and English versions. Results A total of 360 MS patients were included. Patients' ages ranged from 18 to 65 years with a mean age of 34.9±13.2 years old. Exactly 229 (63.6%) patients were females. A total of 104 (28.9%) patients complained of relapsing-remitting MS, 34 (9.4%) complained of primary progressive MS, and 16 (4.4%) complained of secondary progressive MS. A total of 138 (38.3%) patients had the disease for less than five years, and 14 (3.9%) had the disease for more than 21 years. Exactly 124 (34.4%) MS patients complained of high disability due to MSP, while 236 (65.6%) had low disability. Conclusions This study demonstrates that one out of each three patients with MS complained of pain with high disability associated with pain. Old age, comorbidities, long disease duration, and a family history of MS were significant determinants of associated disability severity.

Symptom Interconnectivity in Multiple Sclerosis: A Narrative Review of Potential Underlying Biological Disease Processes

Introduction

Fatigue, cognitive impairment, depression, and pain are highly prevalent symptoms in multiple sclerosis (MS). These often co-occur and may be explained by a common etiology. By reviewing existing literature, we aimed to identify potential underlying biological processes implicated in the interconnectivity between these symptoms.

Methods

A literature search was conducted to identify articles reporting research into the biological mechanisms responsible for the manifestation of fatigue, cognitive impairment, depression, and pain in MS. PubMed was used to search for articles published from July 2011 to July 2021. We reviewed and assessed findings from the literature to identify biological processes common to the symptoms of interest.

Results

Of 693 articles identified from the search, 252 were selected following screening of titles and abstracts and assessing reference lists of review articles. Four biological processes linked with two or more of the symptoms of interest were frequently identified from the literature: (1) direct neuroanatomical changes to brain regions linked with symptoms of interest (e.g., thalamic injury associated with cognitive impairment, fatigue, and depression), (2) pro-inflammatory cytokines associated with so-called ‘sickness behavior,’ including manifestation of fatigue, transient cognitive impairment, depression, and pain, (3) dysregulation of monoaminergic pathways leading to depressive symptoms and fatigue, and (4) hyperactivity of the hypothalamic–pituitary-adrenal (HPA) axis as a result of pro-inflammatory cytokines promoting the release of brain noradrenaline, serotonin, and tryptophan, which is associated with symptoms of depression and cognitive impairment.

Conclusion

The co-occurrence of fatigue, cognitive impairment, depression, and pain in MS appears to be associated with a common set of etiological factors, namely neuroanatomical changes, pro-inflammatory cytokines, dysregulation of monoaminergic pathways, and a hyperactive HPA axis. This association of symptoms and biological processes has important implications for disease management strategies and, eventually, could help find a common therapeutic pathway that will impact both inflammation and neuroprotection.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40120-022-00368-2.

Clinical perspective on pain in multiple sclerosis

Pain is an important and frequent symptom in multiple sclerosis (MS), which leads to a low quality of life, increased disability level, and lack of employment and mental health. Recently, studies have shown increased interest in pain in MS and there is a growing evidence of its prevalence. However, the literature suffers from lack of experimental studies focusing on pain reduction. This topical review summarizes the current knowledge about pain in MS with its definitions, assessments, treatments and rehabilitation within a holistic perspective.

Somatosensory impairments in patients with multiple sclerosis: association with dynamic postural control and upper extremity motor function

Purpose: We planned this study to bring attention to the somatosensory impairments in patients with multiple sclerosis (PwMS) and to investigate relationship of somatosensory impairments with dynamic postural stability and upper extremity motor function.Methods: Seven males and 23 females, 30 patients with mean EDSS 2.9 (SD = 1.4), aged between 18 and 65 years (mean = 41.43 ± 14.90 years) were included in this clinical study. Light touch sensorial assessment was made with Semmes Weinstein monofilament test and proprioception by distal proprioception test. Hand strength was measured by the Jamar dynamometer, fine motor skill was examined with nine-hole peg test, functional reach test in sitting and standing position was applied. Nottingham Extended Activities of Daily Living Scale (NEADLS) was used to measure everyday activities.Results: We found a negative and moderate correlation between FRT in standing and light touch of the middle of the heel (right: -0.515), metatarsal bone (right r: 0.453, left r: -0.426), and medial of the foot (right r: -0.462). There was a negative and moderate correlation between NEADLS and light touch of the metatarsal bone (right r: -0.564, left r: -0.472), medial of the foot (right r: -0.531, left r: -0.479), and lateral of the foot (right r: -0.526). We found a positive and moderate correlation between proprioception of the ankle (right r: 0.421 left r: 0.588) and NEADLS.Conclusions: We found impairment in light touch and proprioception and, associations between sensorial functions and dynamic postural stability in PwMS. Also impaired sensorial functions cause dependent patients in daily living activities. In the assessment of balance and falling risk, independency in daily living activities; foot light touch and proprioception sense should be taken into account, hence it may provide guidance in planning rehabilitation programmes.Abbreviations: MS: multiple sclerosis; PwMS: patients with multiple sclerosis; VAS: visual analogue scale; FRT: functional reach test; 9-HPT: Nine-hole peg test; EDSS: The Expanded Disability Status Scale; NEADLS: Nottingham Extended Activities of Daily Living Scale.

Effectiveness of monopolar dielectric transmission of pulsed electromagnetic fields for multiple sclerosis-related pain: a pilot study

INTRODUCTION

Pain is highly prevalent in patients with multiple sclerosis (MS); it is chronic in 50% of cases and is classified as nociceptive, neuropathic, or mixed-type. Pain affects quality of life, sleep, and the activities of daily living. Electrotherapy is an interesting alternative or complementary treatment in the management of pain in MS, with new innovations constantly appearing.

MATERIAL AND METHODS

This study evaluates the effectiveness of treatment with monopolar dielectric transmission of pulsed electromagnetic fields (PEMF) for pain associated with MS. We performed a randomised, placebo-controlled clinical trial including 24 patients, who were assessed with the Brief Pain Inventory, the Multiple Sclerosis International Quality of Life questionnaire, the Beck Depression Inventory, and the Modified Fatigue Impact Scale.

RESULTS

Statistically significant improvements were observed in maximum and mean pain scores, as well as in the impact of pain on work, personal relationships, and sleep and rest. Not significant differences were found between the treatment and placebo groups.

CONCLUSIONS

Treatment with PEMF may be effective in reducing pain in patients with MS, although further research is necessary to confirm its effectiveness over placebo and to differentiate which type of pain may be more susceptible to this treatment.

Combined upper limb and breathing exercise programme for pain management in ambulatory and non-ambulatory multiple sclerosis individuals: part II analyses from feasibility study

PURPOSE

The present small semi-controlled feasibility study investigated a possible efficacy of a combined upper limb and breathing exercise programme in managing pain in ambulatory and non-ambulatory patients with EDSS from 0.0-8.0.

METHOD

People with MS (N = 19) were enrolled in this single-blind randomized controlled study and divided into 2 groups: exercise group (5 ambulatory, 5 non-ambulatory; Expanded Disability Status Scale (EDSS), 1.0-8.0) and related control group that performed no exercise (4 ambulatory, 5 non-ambulatory; EDSS, 1.0-7.5). The exercise group performed combined upper limb and breathing exercises in a group led by a physiotherapist (2 days/week, 60 min/session) accompanied by independent home exercises (3 days/week, ≥ 20 min/session). Participants underwent measures of pain level (visual analogue scale) for physical pain, functional independence of daily activities (Barthel index) and handgrip strength (HGS) for dominant (D) and non-dominant (ND) hand evaluated by a dynamometer before and after the 4-week period by the blinded assessor.

RESULTS

The VAS for pain showed statistically significant group-by-time interaction only in non-ambulatory (p = .049) individuals, but with large intervention effects on both subgroups (ambulatory, p = .159; non-ambulatory, d = 0.97). Functional independence in daily activities (Barthel index) showed statistically non-significant group-by-time interaction in ambulatory (p = .195, d = 0.89) and non-ambulatory (p = .102, d = 1.64) individuals, but despite the absence of statistical significance, there were large intervention effects. Handgrip strength was significantly improved for both hands in ambulatory (D, p = .012; d = 2.07; ND, p = .025, d = 1.77) and only non-dominant hand in non-ambulatory individuals (D, p = .288, d = 0.83; ND, p = .012, d = 2.21).

CONCLUSION

This small pilot study provides preliminary proof-of-concept data supporting low-intensity upper limb and breathing exercise programme for potential reduction of pain and improvement of functional independence in both ambulatory and non-ambulatory individuals with MS in a larger sample and that strengthening the upper limbs might be an additional pain relief mechanism.

TRIAL REGISTRATION

NTC03222596.

Effectiveness of monopolar dielectric transmission of pulsed electromagnetic fields for multiple sclerosis-related pain: A pilot study

INTRODUCTION

Pain is highly prevalent in patients with multiple sclerosis (MS); it is chronic in 50% of cases and is classified as nociceptive, neuropathic, or mixed-type. Pain affects quality of life, sleep, and the activities of daily living. Electrotherapy is an interesting alternative or complementary treatment in the management of pain in MS, with new innovations constantly appearing.

MATERIAL AND METHODS

This study evaluates the effectiveness of treatment with monopolar dielectric transmission of pulsed electromagnetic fields (PEMF) for pain associated with MS. We performed a randomised, placebo-controlled clinical trial including 24 patients, who were assessed with the Brief Pain Inventory, the Multiple Sclerosis International Quality of Life questionnaire, the Beck Depression Inventory, and the Modified Fatigue Impact Scale.

RESULTS

Statistically significant improvements were observed in maximum and mean pain scores, as well as in the impact of pain on work, personal relationships, and sleep and rest. Not significant differences were found between the treatment and placebo groups.

CONCLUSIONS

Treatment with PEMF may be effective in reducing pain in patients with MS, although further research is necessary to confirm its effectiveness over placebo and to differentiate which type of pain may be more susceptible to this treatment.

Peripheral neuropathy in patients with multiple sclerosis

OBJECTIVES

To determine the prevalence and severity of neuropathic pain, sudomotor dysfunction and abnormal vibration perception in patients with MS.

METHODS

73 patients with MS and 32 age-matched healthy controls underwent assessment of expanded disability severity score (EDSS), DN4 to assess neuropathic pain, electrochemical skin conductance (ESC) to assess sudomotor function and vibration perception threshold (VPT).

RESULTS

Patients with MS had a higher DN4 score (p < 0.001) with 14% fulfilling the criteria for neuropathic pain elevated VPT (p < 0.001) and lower ESC on the feet (p < 0.001) and hands (p < 0.001) compared to control participants. ESC on the feet (32% of MS patients) and hands (30% of MS patients) were lower, and DN4 (77% of MS patients) and VPT (64% of MS patients) were greater than 2SD of the healthy control values, respectively. EDSS correlated with the number of relapses (r = 0.564, p < 0.001), VPT (r = -0.457, < 0.001) and ESC on the feet (r = -0.268, p = 0.023).

CONCLUSIONS

Patients with multiple sclerosis have evidence of sudomotor dysfunction and elevated vibration perception, which were associated with neurological disability from MS.

CaMKIIα Mediates the Effect of IL-17 To Promote Ongoing Spontaneous and Evoked Pain in Multiple Sclerosis

Pain is a common and severe symptom in multiple sclerosis (MS), a chronic inflammatory and demyelinating disease of the CNS. The neurobiological mechanism underlying MS pain is poorly understood. In this study, we investigated the role of Ca²⁺/calmodulin-dependent protein kinase IIα (CaMKIIα) in driving chronic pain in MS using a mouse experimental autoimmune encephalomyelitis (EAE) model. We found that spinal CaMKIIα activity was enhanced in EAE, correlating with the development of ongoing spontaneous pain and evoked hypersensitivity to mechanical and thermal stimuli. Prophylactic or acute administration of KN93, a CaMKIIα inhibitor, significantly reduced the clinical scores of EAE and attenuated mechanical allodynia and thermal hyperalgesia in EAE. siRNA targeting CaMKIIα reversed established mechanical and thermal hypersensitivity in EAE mice. Furthermore, CaMKIIαT286A point mutation mice showed significantly reduced EAE clinical scores, an absence of evoked pain, and ongoing spontaneous pain when compared with littermate wild-type mice. We found that IL-17 is responsible for inducing but not maintaining mechanical and thermal hyperalgesia that is mediated by CaMKIIα signaling in EAE. Together, these data implicate a critical role of CaMKIIα as a cellular mechanism for pain and neuropathy in multiple sclerosis and IL-17 may act upstream of CaMKIIα in the generation of pain.SIGNIFICANCE STATEMENT Pain is highly prevalent in patients with multiple sclerosis (MS), significantly reducing patients' quality of life. Using the experimental autoimmune encephalomyelitis (EAE) model, we were able to study not only evoked hyperalgesia, but also for the first time to demonstrate spontaneous pain that is also experienced by patients. Our study identified a role of spinal CaMKIIα in promoting and maintaining persistent ongoing spontaneous pain and evoked hyperalgesia pain in EAE. We further demonstrated that IL-17 contributes to persistent pain in EAE and functions as an upstream regulator of CaMKIIα signaling. These data for the first time implicated CaMKIIα and IL-17 as critical regulators of persistent pain in EAE, which may ultimately offer new therapeutic targets for mitigating pain in multiple sclerosis.

Pain in People with Multiple Sclerosis: Associations with Modifiable Lifestyle Factors, Fatigue, Depression, Anxiety, and Mental Health Quality of Life

Background

People with multiple sclerosis (MS) often experience pain, which can interfere with mobility, employment, and quality of life (QOL).

Methods

This cross-sectional study explored associations between pain, demographic, disease, and modifiable lifestyle factors in an international sample of people with MS recruited online.

Results

Substantial pain, of moderate/severe intensity and interfering at least moderately with work/household or enjoyment of life in the past 4 weeks, was reported by 682/2,362 (28.9%). Substantial pain was associated with fatigue (odds ratio (OR): 6.7, 95% confidence interval (CI): 4.9,9.3), depression (OR:4.0, 95% CI:3.2,5.1), anxiety (OR:2.4, 95% CI:1.9,2.9), and lower mental health QOL (Mean Difference: −14.7, 95% CI:−16.6,−12.8). Regression analyses showed that smoking (OR: 2.0, 95% CI:1.35,2.87) and obesity (OR:2.1, 95% CI: 1.5,2.8), moderate alcohol use (OR: 0.7, 95% CI:0.5,0.9), moderate (OR 0.7, 95% CI: 0.55,0.98) or high (OR 0.6, 95% CI: 0.4,0.8) physical activity level, and healthy diet (OR 0.8, 95% CI: 0.75,0.95, per 10 points) were associated with substantial pain.

Conclusion

Our results show clear associations with modifiable lifestyle factors and substantial pain in MS. These factors are already considered in the prevention and management of pain in other populations but have not previously been considered in MS. Conversely, pain and associated common MS comorbidities, such as depression, anxiety, and fatigue, may hamper efforts to start or maintain healthy behaviors. Strategies to overcome these barriers need to be considered. Further research should clarify the direction of these associations.

Hippotherapy for patients with multiple sclerosis: A multicenter randomized controlled trial (MS-HIPPO)

Background:

Evidence-based complementary treatment options for multiple sclerosis (MS) are limited.

Objective:

To investigate the effect of hippotherapy plus standard care versus standard care alone in MS patients.

Methods:

A total of 70 adults with MS were recruited in five German centers and randomly allocated to the intervention group (12 weeks of hippotherapy) or the control group. Primary outcome was the change in the Berg Balance Scale (BBS) after 12 weeks, and further outcome measures included fatigue, pain, quality of life, and spasticity.

Results:

Covariance analysis of the primary endpoint resulted in a mean difference in BBS change of 2.33 (95% confidence interval (CI): 0.03–4.63, p = 0.047) between intervention ( n = 32) and control ( n = 38) groups. Benefit on BBS was largest for the subgroup with an Expanded Disability Status Scale (EDSS) ⩾ 5 (5.1, p = 0.001). Fatigue (−6.8, p = 0.02) and spasticity (−0.9, p = 0.03) improved in the intervention group. The mean difference in change between groups was 12.0 ( p < 0.001) in physical health score and 14.4 ( p < 0.001) in mental health score of Multiple Sclerosis Quality of Life-54 (MSQoL-54).

Conclusion:

Hippotherapy plus standard care, while below the threshold of a minimal clinically important difference, significantly improved balance and also fatigue, spasticity, and quality of life in MS patients.

Oral Palmitoylethanolamide Treatment Is Associated with Reduced Cutaneous Adverse Effects of Interferon-β1a and Circulating Proinflammatory Cytokines in Relapsing-Remitting Multiple Sclerosis

Palmitoylethanolamide (PEA) is an endogenous lipid mediator known to reduce pain and inflammation. However, only limited clinical studies have evaluated the effects of PEA in neuroinflammatory and neurodegenerative diseases. Multiple sclerosis (MS) is a chronic autoimmune and inflammatory disease of the central nervous system. Although subcutaneous administration of interferon (IFN)-β1a is approved as first-line therapy for the treatment of relapsing-remitting MS (RR-MS), its commonly reported adverse events (AEs) such as pain, myalgia, and erythema at the injection site, deeply affect the quality of life (QoL) of patients with MS. In this randomized, double-blind, placebo-controlled study, we tested the effect of ultramicronized PEA (um-PEA) added to IFN-β1a in the treatment of clinically defined RR-MS. The primary objectives were to estimate whether, with um-PEA treatment, patients with MS perceived an improvement in pain and a decrease of the erythema width at the IFN-β1a injection site in addition to an improvement in their QoL. The secondary objectives were to evaluate the effects of um-PEA on circulating interferon-γ, tumor necrosis factor-α, and interleukin-17 serum levels, N-acylethanolamine plasma levels, Expanded Disability Status Scale (EDSS) progression, and safety and tolerability after 1 year of treatment. Patients with MS receiving um-PEA perceived an improvement in pain sensation without a reduction of the erythema at the injection site. A significant improvement in QoL was observed. No significant difference was reported in EDSS score, and um-PEA was well tolerated. We found a significant increase of palmitoylethanolamide, anandamide and oleoylethanolamide plasma levels, and a significant reduction of interferon-γ, tumor necrosis factor-α, and interleukin-17 serum profile compared with the placebo group. Our results suggest that um-PEA may be considered as an appropriate add-on therapy for the treatment of IFN-β1a-related adverse effects in RR-MS.

Study of the effectiveness of hippotherapy on the symptoms of multiple sclerosis - Outline of a randomised controlled multicentre study (MS-HIPPO)

Background

Hippotherapy is a form of therapeutic riding which is used in the treatment of neurological and muscular disorders. Until now there has not been any high-quality randomised study that has proven its effectiveness.

Objective

The aims of this study are to evaluate whether hippotherapy (as add-on to physiotherapy and/or pharmacotherapy) is superior to the standard treatment (physiotherapy and/or pharmacotherapy as prior to the study) in terms of balance function and other patient relevant outcomes in patients with multiple sclerosis.

Methods

The MS-HIPPO study is a prospective, randomised, examiner-blinded, controlled multicentre study. Patients were randomised to one of two groups: 12 weeks of hippotherapy accompanied by physiotherapy and/or pharmacotherapy (intervention) or 12 weeks of physiotherapy and/or pharmacotherapy as prior to the study (control). The primary endpoint is the change in balance function, as measured by the Berg Balance Scale (BBS). The treatment comparison is evaluated using a covariance analysis with baseline BBS, centre, age, gender and EDSS as covariates. Secondary endpoints include fatigue, quality of life, pain intensity and spasticity.

Results and conclusions

The described study is the first randomised study evaluating the benefits of hippotherapy for patients with multiple sclerosis. In 5 national centres ten study physicians will screen potential participants. The expected results will help to improve the knowledge on non-pharmaceutical therapeutic options in this field.

The Prevalence of Pain in Adults with Multiple Sclerosis: A Multicenter Cross-Sectional Survey

OBJECTIVE

Examination of prevalence, intensity and associations of pain in persons with multiple sclerosis (MS).

DESIGN

Multicenter, international cross-sectional survey.

SETTING

Patients were recruited from seven MS centers: in Serbia (Clinic of Neurology, Clinical Center of Serbia, Belgrade; Clinic of Neurology, Military Medical Academy, Belgrade; Clinic of Neurology, Clinical Center Kragujevac; Clinic of Neurology, Clinical Center Nis; Department of Neurology, General Hospital-Uzice), in Republic of Srpska-Bosnia and Herzegovina (Clinic of Neurology, Clinical Center Banja Luka) and in Croatia (University Department of Neurology, Sestre Milosrdnice University Hospital Center, Zagreb).

SUBJECTS

Six hundred and fifty consecutive MS patients diagnosed according to the Revised McDonald criteria (2005), from the aforementioned centers, over the period of 6 months.

METHODS

A semistructured questionnaire was administered during a face-to-face interview with neurologists who also performed Expanded Disability Status Scale (EDSS), the Hamilton Rating Scale for Depression (HDRS) and Hamilton Rating Scale for Anxiety (HARS). To recognize predictive factors for the presence of pain, the linear regression analysis was used.

RESULTS

Lifetime prevalence of pain was 66.5% (point prevalence = 44.3%). The prevalence of the comorbidity of pain and depression was 29.1%. Older age (P < 0.001), primary-progressive MS (P = 0.034), higher EDSS score (P = 0.008), higher scores of HDRS (P < 0.001), and HARS (P < 0.001) were significantly associated with pain. Finally, in our multivariate linear regression analysis, anxiety (P < 0.001) was the independent predictor of pain.

CONCLUSIONS

We confirmed high prevalence of pain, affecting approximately more than half of patients during the course of MS. Pain in MS is associated with disability, depression and, especially with anxiety, which has significant implications for treatment.

Chronic Pain in Multiple Sclerosis Patients: Utility of Sensory Quantitative Testing in Patients with Fibromyalgia Comorbidity

BACKGROUND

Lower thermal and discomfort thresholds may predispose multiple sclerosis (MS) patients to chronic pain, but a possible effect of fibromyalgia (FM) comorbidity has never been investigated. Aims were to investigate the thermal and discomfort thresholds in the evaluation of pain intensity between MS patients with FM (PFM+) and MS patients with pain not associated to FM (PFM-).

METHODS

One hundred thirty three MS patients were investigated for chronic pain. FM was assessed according to the 1990 ACR diagnostic criteria. An algometer was used to measure the thresholds in the patients and 60 matched healthy subjects.

RESULTS

Chronic pain was present in 88 (66.2%) patients; 12 (13.6%) had neuropathic pain, 22 (17.3%) were PFM+ and 65 (48.9%) PFM-. PFM+ were predominantly female (p = 0.03) and had a greater EDSS (p = 0.01) than NoP; no other significant differences emerged than PFM-. The thresholds were lower in MS patients than controls (p < 0.01), mainly in the PFM+. FM severity influenced the thermal threshold (p < 0.001), while the female gender influenced the discomfort threshold (p < 0.001).

CONCLUSION

Thermal and discomfort thresholds were lower in patients than controls and were the lowest in PFM+. Their more severely impaired thermal threshold supports a neurophysiological basis of such association.

Chronic pain in multiple sclerosis: is there also fibromyalgia? An observational study

Background

Chronic pain is common in persons with multiple sclerosis (MS), but the co-morbidity of fibromyalgia (FM) has yet to be investigated in MS. Objectives of the study were to evaluate, among the various types of chronic pain, the frequency of FM in MS and its impact on MS patients’ health-related quality of life (HRQoL).

Material/Methods

133 MS patients were investigated for the presence and characterization of chronic pain within 1 month of assessment. A rheumatologist assessed the presence FM according to the 1990 ACR diagnostic criteria. Depression, fatigue, and HRQoL were also assessed by means of specific scales.

Results

Chronic pain was present in 66.2% of patients (musculoskeletal in 86.3%; neuropathic in 13.7%; absent in 33.8% [called NoP]). Pain was diagnosed with FM (PFM+) in 17.3% of our MS patients, while 48.9% of them had chronic pain not FM type (PFM−); the prevalence of neuropathic pain in these 2 sub-groups was the same. PFM+ patients were prevalently females and had a higher EDSS than NoP. The PFM+ patients had a more pronounced depression than in the NoP group, and scored the worst in both physical and mental QoL.

Conclusions

In our sample of MS patients we found a high prevalence of chronic pain, with those patients displaying a higher disability and a more severe depression. Moreover, FM frequency, significantly higher than that observed in the general population, was detected among the MS patients with chronic pain. FM occurrence was associated with a stronger impact on patients’ QoL.

Cytokine-related and histological biomarkers for neuropathic pain assessment

SUMMARY Neuropathic pain (NP) is a disabling condition that may occur following a disease or a lesion of the somatosensory nervous system. With an estimated prevalence of up to 8.2% in the general population, NP is common, and robust and objective diagnostic tools are warranted for pain assessment and follow-up. In the last years research has focused on defining biochemical and histological markers for this purpose, and possible systemic (blood, cerebrospinal fluid) and local (skin and nerve) targets have been investigated in a number of different NP disorders. This article focuses on an update giving an overview over some potential biomarkers for the diagnosis of NP, and will discuss their clinical relevance.

Mechanisms and pharmacology of neuropathic pain in multiple sclerosis

The neuropathic pain of multiple sclerosis is quite prevalent and severely impacts quality of life. A few randomized, placebo-controlled, blinded clinical trials suggest that cannabis- and anticonvulsant-based treatments provide partial pain relief, but at the expense of adverse events. An even smaller, but emerging, number of translational studies are using rodent models of experimental autoimmune encephalomyelitis (EAE), which exhibit pain-like behaviors resembling those of Multiple sclerosis (MS) patients. These studies not only support the possible effectiveness of anticonvulsants, but also compel further clinical trials with serotonin-norepinephrine reuptake inhibitors, the immunosuppressant drug rapamycin, or drugs which interfere with glutamatergic neurotransmission. Future behavioral studies in EAE models are essential toward a new pharmacotherapy of multiple sclerosis pain.

Validity of an observation method for assessing pain behavior in individuals with multiple sclerosis

CONTEXT

Pain is a common and complex experience for individuals who live with multiple sclerosis (MS) and it interferes with physical, psychological, and social function. A valid and reliable tool for quantifying observed pain behaviors in MS is critical to understand how pain behaviors contribute to pain-related disability in this clinical population.

OBJECTIVES

To evaluate the reliability and validity of a pain behavioral observation protocol in individuals who have MS.

METHODS

Community-dwelling volunteers with MS (N=30), back pain (N=5), or arthritis (N=8) were recruited based on clinician referrals, advertisements, fliers, web postings, and participation in previous research. Participants completed the measures of pain severity, pain interference, and self-reported pain behaviors and were videotaped doing typical activities (e.g., walking and sitting). Two coders independently recorded frequencies of pain behaviors by category (e.g., guarding and bracing) and interrater reliability statistics were calculated. Naïve observers reviewed videotapes of individuals with MS and rated their pain. The Spearman's correlations were calculated between pain behavior frequencies and self-reported pain and pain ratings by naïve observers.

RESULTS

Interrater reliability estimates indicated the reliability of pain codes in the MS sample. Kappa coefficients ranged from moderate (sighing=0.40) to substantial agreements (guarding=0.83). These values were comparable with those obtained in the combined back pain and arthritis sample. Concurrent validity was supported by correlations with self-reported pain (0.46-0.53) and with self-reports of pain behaviors (0.58). Construct validity was supported by a finding of 0.87 correlation between total pain behaviors observed by coders and mean pain ratings by naïve observers.

CONCLUSION

Results support the use of the pain behavior observation protocol for assessing pain behaviors of individuals with MS. Valid assessments of pain behaviors of individuals with MS could lead to creative interventions in the management of chronic pain in this population.

Neurological diseases and pain

Chronic pain is a frequent component of many neurological disorders, affecting 20-40% of patients for many primary neurological diseases. These diseases result from a wide range of pathophysiologies including traumatic injury to the central nervous system, neurodegeneration and neuroinflammation, and exploring the aetiology of pain in these disorders is an opportunity to achieve new insight into pain processing. Whether pain originates in the central or peripheral nervous system, it frequently becomes centralized through maladaptive responses within the central nervous system that can profoundly alter brain systems and thereby behaviour (e.g. depression). Chronic pain should thus be considered a brain disease in which alterations in neural networks affect multiple aspects of brain function, structure and chemistry. The study and treatment of this disease is greatly complicated by the lack of objective measures for either the symptoms or the underlying mechanisms of chronic pain. In pain associated with neurological disease, it is sometimes difficult to obtain even a subjective evaluation of pain, as is the case for patients in a vegetative state or end-stage Alzheimer's disease. It is critical that neurologists become more involved in chronic pain treatment and research (already significant in the fields of migraine and peripheral neuropathies). To achieve this goal, greater efforts are needed to enhance training for neurologists in pain treatment and promote greater interest in the field. This review describes examples of pain in different neurological diseases including primary neurological pain conditions, discusses the therapeutic potential of brain-targeted therapies and highlights the need for objective measures of pain.