Clinical perspective on pain in multiple sclerosis

Mechanisms of pain in aging and age-related conditions: Focus on caregivers

Pain is a complex, subjective experience that can significantly impact quality of life, particularly in aging individuals, by adversely affecting physical and emotional well-being. Whereas acute pain usually serves a protective function, chronic pain is a persistent pathological condition that contributes to functional deficits, cognitive decline, and emotional disturbances in the elderly. Despite substantial progress that has been made in characterizing age-related changes in pain, complete mechanistic details of pain processing mechanisms in the aging patient remain unknown. Pain is particularly under-recognized and under-managed in the elderly, especially among patients with Alzheimer's disease (AD), Alzheimer's disease-related dementias (ADRD), and other age-related conditions. Furthermore, difficulties in assessing pain in patients with AD/ADRD and other age-related conditions may contribute to the familial caregiver burden. The purpose of this article is to discuss the mechanisms and risk factors for chronic pain development and persistence, with a particular focus on age-related changes. Our article also highlights the importance of caregivers working with aging chronic pain patients, and emphasizes the urgent need for increased legislative awareness and improved pain management in these populations to substantially alleviate caregiver burden.

Electrical stimulation therapy for pain and related symptoms in multiple sclerosis: A systematic review and meta-analysis

BACKGROUND

The effectiveness of electrical stimulation therapy (EST) for pain, depression, fatigue, disability, and quality of life in multiple sclerosis (MS) remains uncertain. This study aims to analyze and discuss the efficacy of various EST treatments in alleviating pain among MS patients.

METHODS

The primary search was conducted using PubMed, Web of Science, Cochrane Library, Embase, and the Cumulative Index of Nursing and Allied Health Literature databases until September 25, 2023. Randomized controlled trials (RCTs) including patients with MS pain receiving EST compared with other therapies were included. Pain intensity, quality of life, and neuropsychiatric symptoms were reported. The mean difference (MD) with 95 % confidence intervals (CIs) was estimated separately for outcomes to understand the mean effect size.

RESULTS

Ten RCTs containing 315 participants were included. The pooled data from 8 trials including 267 participants showed that the EST was superior in alleviating pain (MD = -1.75, 95 % CI -2.85--0.64, P = 0.002, I2=73 %) evaluated by the visual analog scale. In subgroup analysis, medium-term EST treatment showed the highest effect size compared to short-term and long-term treatment (MDmedium-term = -2.17, 95 % CI -3.51--0.84, P = 0.001, I2 = 0 %). However, no significant differences were found in terms of pain-related quality of life, depression, fatigue, and pain-related disability. No adverse events related to EST were reported. A high risk of bias was identified in three of the ten included studies.

CONCLUSIONS

EST is effective and safe for alleviating pain in MS, but it should be noted that limited sample sizes and methodological issues were present in the included studies. More robust assessment criteria and high-quality RCTs are required for patients with MS.

TRIAL REGISTRATION

CRD42023406787. (https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=406787).

The MoxFo initiative - outcomes: Outcome measures in studies of exercise training in multiple sclerosis; scoping review of reviews and classification according to the ICF framework

BACKGROUND

The number of published studies of exercise training in multiple sclerosis (MS) has grown exponentially with increasing numbers of outcomes capturing exercise effects. This has complicated the selection of relevant indicators and interpretation of intervention effects.

OBJECTIVES

The Outcomes subgroup of the MoXFo initiative aimed to (1) identify outcome measures and biomarkers in studies of exercise training in MS; (2) systematically map retrieved outcomes to International Classification of Functioning, Disability and Health (ICF) categories; (3) identify gaps where relevant ICF categories have been omitted.

METHODS

Electronic databases and registers were searched from 2010 to July 2020 to identify systematic reviews or meta-analyses of controlled trials of exercise training on any outcome in MS. Retrieved outcomes/biomarkers were mapped to the corresponding ICF category.

RESULTS

Eighty-one review articles reporting 235 different outcomes were included. The outcomes corresponded to 15 chapters and 45 categories within the ICF. Outcomes mapped primarily to body function (30 categories) and activities and participation (9 categories) components. Few outcomes mapped to body structures (2 categories) or environmental factors (1 category).

CONCLUSION

This sets the stage to develop a resource for researchers/clinicians that will aid in the selection of appropriate outcomes/biomarkers when examining exercise effects in MS.

Interim guidelines for the assessment and treatment of pain in children with multiple sclerosis

Introduction

Pain in multiple sclerosis (MS) is common, but literature on pain in children with MS remains scarce. Pain has physical, psychological, and social implications in MS, and both comprehensive assessment and interdisciplinary management approaches are needed. We sought to develop an interdisciplinary interim guideline for the assessment and management of pain in children with MS.

Methods and materials

We convened a modified Delphi panel composed of 13 experts in pediatric and adult MS neurology, physiotherapy, pain, patient lived-experience, advanced practice nursing, psychology, physiatry, and MS research. A survey was sent to panelists for anonymous completion. The panel discussed survey themes extracted by the panel chair. The process was repeated twice.

Results

Thirteen assessment and treatment recommendations were produced regarding pain in children with MS.

Discussion

Future studies will assess implementation of these pain assessment and treatment guidelines in the clinical setting.

Clinical application of transcranial magnetic stimulation in multiple sclerosis

Multiple sclerosis (MS) is a common chronic, autoimmune-mediated inflammatory and neurodegenerative disease of the central nervous system. The treatment of MS has enormous progress with disease-modifying drugs, but the complexity of the disease course and the clinical symptoms of MS requires personalized treatment and disease management, including non-pharmacological treatment. Transcranial magnetic stimulation (TMS) is a painless and non-invasive brain stimulation technique, which has been widely used in neurological diseases. In this review, we mainly focus on the progress of physiological assessment and treatment of TMS in MS.

Effectiveness of non-pharmacological rehabilitation interventions in pain management in patients with multiple sclerosis: Systematic review and meta-analysis

BACKGROUND

Multiple sclerosis (MS) is a progressive inflammatory and autoimmune neurological disease caused by inflammation and demyelination of the central nervous system. Pain is a typical symptom of central nervous system demyelination, affecting 63% of adults with MS. Recently, the role of non-pharmacological pain management in patients is growing because the non-pharmacological interventions are considered safe, affordable, easy, and accessible. However, to date, no systematic reviews or meta-analyses have comprehensively examined the therapeutic effects of the variety of non-pharmacological therapeutic interventions in the management of pain in patients with MS.

OBJECTIVE

The study aimed to conduct a systematic review with meta-analysis to assess the effectiveness of the non-pharmacological rehabilitation interventions in pain management in patients with MS.

METHODS

A comprehensive search using PubMed, Cochrane, and Science Direct databases was performed and included all randomized controlled trials, randomized cross-over trials, and quasi-experimental trials assessing the effect of non-pharmacological interventions for managing pain in patients with MS. This study was conducted according to PRISMA guidelines of a systematic review and pair-wise meta-analysis. Meta-analyses were performed by calculating the standardized mean difference at a 95% confidence interval using Review Manager software.

RESULTS

Twenty-nine papers were included in the systematic review, and only 22 of them were included in the meta-analysis. The pooled analysis showed a significant effect of neuromodulation and transcranial direct current stimulation on pain intensity reduction in patients with MS (SMD -0.51, 95% CI -0.51 to -0.09, P = 0.02), (SMD -0.67, 95% CI -1.18 to -0.16 P = 0.01), respectively. The analysis showed significant improvement in pain intensity in patient with MS after mind-body therapies (SMD -0.45, 95% CI -0.82 to -0.7, P = 0.02), mindfulness (SMD -0.55, 95% CI -0.96 to -0.14, P = 0.009), hypnosis (SMD -0.88, 95% CI -1.30 to -0.46, P = 0.0001), trigger point therapies (SMD -0.83, 95% CI -1.65 to -0.01, P = 0.05) and cognitive behavioral therapy (SMD -0.64, 95% CI -1.18 to -0.11, P = 0.02). However, there is no significant effect of relaxation therapy on pain reduction in patients with MS (SMD -0.82, 95% CI -1.94 to 0.31, P = 0.15).

CONCLUSIONS

The results indicated that the majority of the non-pharmacological rehabilitation interventions showed potential therapeutic effects in reducing pain intensity in patients with MS.

Brain Under Fatigue – Can Perceived Fatigability in Multiple Sclerosis Be Seen on the Level of Functional Brain Network Architecture?

Background

Fatigue is one of the most common symptoms of multiple sclerosis (MS), significantly affecting the functioning of the patients. However, the neural underpinnings of physical and mental fatigue in MS are still vague. The aim of our study was to investigate the functional architecture of resting-state networks associated with fatigue in patients with MS.

Methods

The sum of 107 high-functioning patients underwent a resting-state scanning session and filled out the 9-item Fatigue Severity Scale (FSS). Based on the FSS score, we identified patients with different levels of fatigue using the cluster analysis. The low-fatigue group consisted of n = 53 subjects, while the high-fatigue group n = 48. The neuroimaging data were analyzed in terms of functional connectivity (FC) between various resting-state networks as well as amplitude of low-frequency fluctuation (ALFF) and fractional amplitude of low-frequency fluctuations (fALFF).

Results

Two-sample t-test revealed between-group differences in FC of posterior salience network (SN). No differences occurred in default mode network (DMN) and sensorimotor network (SMN). Moreover, differences in fALFF were shown in the right middle frontal gyrus and right superior frontal gyrus, however, no ALFF differences took place.

Conclusion

Current study revealed significant functional network (FN) architecture between-group differences associated with fatigue. Present results suggest the higher level of fatigue is related to deficits in awareness as well as higher interoceptive awareness and nociception.

In-Depth Characterization of Somatic and Orofacial Sensitive Dysfunctions and Interfering-Symptoms in a Relapsing-Remitting Experimental Autoimmune Encephalomyelitis Mouse Model

Among the many symptoms (motor, sensory, and cognitive) associated with multiple sclerosis (MS), chronic pain is a common disabling condition. In particular, neuropathic pain symptoms are very prevalent and debilitating, even in early stages of the disease. Unfortunately, chronic pain still lacks efficient therapeutic agents. Progress is needed (i) clinically by better characterizing pain symptoms in MS and understanding the underlying mechanisms, and (ii) preclinically by developing a more closely dedicated model to identify new therapeutic targets and evaluate new drugs. In this setting, new variants of experimental autoimmune encephalomyelitis (EAE) are currently developed in mice to exhibit less severe motor impairments, thereby avoiding confounding factors in assessing pain behaviors over the disease course. Among these, the optimized relapsing-remitting EAE (QuilA-EAE) mouse model, induced using myelin oligodendrocyte glycoprotein peptide fragment (35–55), pertussis toxin, and quillaja bark saponin, seems very promising. Our study sought (i) to better define sensitive dysfunctions and (ii) to extend behavioral characterization to interfering symptoms often associated with pain during MS, such as mood disturbances, fatigue, and cognitive impairment, in this optimized QuilA-EAE model. We made an in-depth characterization of this optimized QuilA-EAE model, describing for the first time somatic thermal hyperalgesia associated with mechanical and cold allodynia. Evaluation of orofacial pain sensitivity showed no mechanical or thermal allodynia. Detailed evaluation of motor behaviors highlighted slight defects in fine motor coordination in the QuilA-EAE mice but without impact on pain evaluation. Finally, no anxiety-related or cognitive impairment was observed during the peak of sensitive symptoms. Pharmacologically, as previously described, we found that pregabalin, a treatment commonly used in neuropathic pain patients, induced an analgesic effect on mechanical allodynia. In addition, we showed an anti-hyperalgesic thermal effect on this model. Our results demonstrate that this QuilA-EAE model is clearly of interest for studying pain symptom development and so could be used to identify and evaluate new therapeutic targets. The presence of interfering symptoms still needs to be further characterized.

Prioritizing progressive MS rehabilitation research: A call from the International Progressive MS Alliance

Background:

People with multiple sclerosis (MS) experience myriad symptoms that negatively affect their quality of life. Despite significant progress in rehabilitation strategies for people living with relapsing-remitting MS (RRMS), the development of similar strategies for people with progressive MS has received little attention.

Objective:

To highlight key symptoms of importance to people with progressive MS and stimulate the design and implementation of high-quality studies focused on symptom management and rehabilitation.

Methods:

A group of international research experts, representatives from industry, and people affected by progressive MS was convened by the International Progressive MS Alliance to devise research priorities for addressing symptoms in progressive MS.

Results:

Based on information from the MS community, we outline a rationale for highlighting four symptoms of particular interest: fatigue, mobility and upper extremity impairment, pain, and cognitive impairment. Factors such as depression, resilience, comorbidities, and psychosocial support are described, as they affect treatment efficacy.

Conclusions:

This coordinated call to action—to the research community to prioritize investigation of effective symptom management strategies, and to funders to support them—is an important step in addressing gaps in rehabilitation research for people affected by progressive MS.