Multiple sclerosis-related fatigue lacks a unified definition: A narrative review

Dalfampridine in the treatment of primary fatigue in patients with multiple sclerosis: a randomized clinical trail

INTRODUCTION

Fatigue is a highly prevalent debilitating symptom among patients with multiple sclerosis (PwMS), which markedly affects the quality of life. The present study aimed to evaluate the effect of extended-release fampridine on fatigue in PwMS.

METHODS

This was a randomized, double-blind clinical trial on 77 PwMS with a complaint of fatigue, aged over 18 years old, randomized to extended-release fampridine (n = 44) or placebo (n = 35) for 12 weeks. Fatigue and motor function were assessed at baseline and end point.

RESULTS

A total of 88 patients were recruited, of whom 77 were analyzed. 80.5% were female, with a median age of 38. 87% were diagnosed with relapsing-remitting MS (RRMS) with a median disease duration of 96 months. Fingolimod (37.7%) was considered the most frequently used DMT, followed by ani-CD20s (32.5%). The total median MFIS score was 43.5 and 37 in the fampridine and placebo groups which were not significantly different (p > 0.05). After 12 weeks, the total MFIS improved in both groups compared to the baseline, which was significant in the active group (p = 0.04). However, the final end point total MFIS was still comparable between the two groups (p = 0.11).

CONCLUSION

The present study revealed a positive short-term effect of extended-release fampridine on MFIS in PwMS. However, this effect was not significantly superior to the placebo.

Possible Role of Fibrinaloid Microclots in Postural Orthostatic Tachycardia Syndrome (POTS): Focus on Long COVID

Postural orthostatic tachycardia syndrome (POTS) is a common accompaniment of a variety of chronic, inflammatory diseases, including long COVID, as are small, insoluble, 'fibrinaloid' microclots. We here develop the argument, with accompanying evidence, that fibrinaloid microclots, through their ability to block the flow of blood through microcapillaries and thus cause tissue hypoxia, are not simply correlated with but in fact, by preceding it, may be a chief intermediary cause of POTS, in which tachycardia is simply the body's exaggerated 'physiological' response to hypoxia. Similar reasoning accounts for the symptoms bundled under the term 'fatigue'. Amyloids are known to be membrane disruptors, and when their targets are nerve membranes, this can explain neurotoxicity and hence the autonomic nervous system dysfunction that contributes to POTS. Taken together as a system view, we indicate that fibrinaloid microclots can serve to link POTS and fatigue in long COVID in a manner that is at once both mechanistic and explanatory. This has clear implications for the treatment of such diseases.

The role of clinical neurophysiology in the definition and assessment of fatigue and fatigability

Though a common symptom, fatigue is difficult to define and investigate, occurs in a wide variety of neurological and systemic disorders, with differing pathological causes. It is also often accompanied by a psychological component. As a symptom of long-term COVID-19 it has gained more attention. In this review, we begin by differentiating fatigue, a perception, from fatigability, quantifiable through biomarkers. Central and peripheral nervous system and muscle disorders associated with these are summarised. We provide a comprehensive and objective framework to help identify potential causes of fatigue and fatigability in a given disease condition. It also considers the effectiveness of neurophysiological tests as objective biomarkers for its assessment. Among these, twitch interpolation, motor cortex stimulation, electroencephalography and magnetencephalography, and readiness potentials will be described for the assessment of central fatigability, and surface and needle electromyography (EMG), single fibre EMG and nerve conduction studies for the assessment of peripheral fatigability. The purpose of this review is to guide clinicians in how to approach fatigue, and fatigability, and to suggest that neurophysiological tests may allow an understanding of their origin and interactions. In this way, their differing types and origins, and hence their possible differing treatments, may also be defined more clearly.

Management of multiple sclerosis fatigue in the digital age: from assessment to treatment

Fatigue is one of the most disabling symptoms of Multiple Sclerosis (MS), affecting more than 80% of patients over the disease course. Nevertheless, it has a multi-faceted and complex nature, making its diagnosis, evaluation, and treatment extremely challenging in clinical practice. In the last years, digital supporting tools have emerged to support the care of people with MS. These include not only smartphone or table-based apps, but also wearable devices or novel techniques such as virtual reality. Furthermore, an additional effective and cost-efficient tool for the therapeutic management of people with fatigue is becoming increasingly available. Virtual reality and e-Health are viable and modern tools to both assess and treat fatigue, with a variety of applications and adaptability to patient needs and disability levels. Most importantly, they can be employed in the patient's home setting and can not only bridge clinic visits but also be complementary to the monitoring and treatment means for those MS patients who live far away from healthcare structures. In this narrative review, we discuss the current knowledge and future perspectives in the digital management of fatigue in MS. These may also serve as sources for research of novel digital biomarkers in the identification of disease activity and progression.

Patterns of attention deficit in relapsing and progressive phenotypes of multiple sclerosis

Behavioral aspects and underlying pathology of attention deficit in multiple sclerosis (MS) remain unknown. This study aimed to clarify impairment of attention and its relationship with MS-related fatigue. Thirty-four relapse-remitting MS (RRMS), 35 secondary-progressive MS (SPMS) and 45 healthy controls (HC) were included. Results of psychophysics tasks (attention network test (ANT) and Posner spatial cueing test) and fatigue assessments (visual analogue scale and modified fatigue impact scale (MFIS)) were compared between groups. In ANT, attentional network effects were not different between MS phenotypes and HC. In Posner task, RRMS or SPMS patients did not benefit from valid cues unlike HC. RRMS and SPMS patients had less gain in exogenous trials with 62.5 ms cue-target interval time (CTIT) and endogenous trials with 250 ms CTIT, respectively. Total MFIS was the predictor of gain in 250 ms endogenous blocks and cognitive MFIS predicted orienting attentional effect. Executive attentional effect in RRMS patients with shorter disease duration and orienting attentional effect in longer diagnosed SPMS were correlated with MFIS scores. The pattern of attention deficit in MS differs between phenotypes. Exogenous attention is impaired in RRMS patients while SPMS patients have deficit in endogenous attention. Fatigue trait predicts impairment of endogenous and orienting attention in MS.

What we know about fatigue self-management programs for people living with chronic conditions: A scoping review

OBJECTIVE

The significant impact of fatigue on the lives of patients with chronic conditions has demanded a response. One response has been the development and testing of self-management programs. Little is known about what these programs have in common or how they differ. This scoping review compared the key components of fatigue self-management programs.

METHODS

Scoping review methodology was employed. Databases of CINAHL, Academic Search Premier, PsycINFO, Cochrane and Medline were searched to identify relevant sources.

RESULTS

Included fatigue programs were compared using a three-component framework: 1) self-management strategies; 2) active patient participation; and 3) self-management support. Although all programs included some aspects of these components, the extent varied with only a few domains of these components found across all programs.

CONCLUSION

The three self-management components employed in this study showed potential benefits in identifying similarities and differences across fatigue programs with comparable and distinct underlying theories. This three-component framework could facilitate identification of domains associated with positive outcomes.

PRACTICE IMPLICATIONS

It is essential that authors of programs provide detailed descriptions to enable inter-program comparison. The three-component framework chosen for this review was capable of describing and comparing fatigue self-management programs, paving the way for more effective interventions.

Non-invasive brain stimulation therapy on neurological symptoms in patients with multiple sclerosis: A network meta analysis

OBJECTIVE

The aim of the study was to evaluate non-invasive brain stimulation (NIBS) [including transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (tES)] on neurological symptoms in patients with multiple sclerosis (PwMS).

METHOD

We searched PubMed, Embase, Cochrane Library, Web of Science and Ovid MEDLINE until February 2022. And we evaluated the included studies for methodological quality by the Cochrane bias risk assessment tool and assessed the studies' certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework. We performed network meta analysis (NMA) by using Stata 15 and ranked the results of the NMA by using the surface under the cumulative ranking curve (SUCRA) ranking chart.

RESULT

Twenty seven clinical trials were finally included (N = 596, 66.4% women). For the immediate effects, rTMS over M1 yielded the most optimal scheme for fatigue reduction among all the interventions compared to the sham stimulation groups [MD = -0.85, 95% CI (-1.57, -0.14)] (SUCRA = 82.6%). iTBS over M1 yielded the most signifcant reduced pain level than the sham groups did [MD = -1.26, 95% CI (-2.40, -0.11)] (SUCRA = 98.4%). tDCS over F3 was the best protocol of NIBS to improve quality of life (QOL) [MD = 1.41, 95% CI = (0.45,2.36)] (SUCRA = 76.7%), and iTBS over M1 may significantly reduce spasticity compared to sham stimulation [MD = -1.20, 95% CI = (-1.99, -0.41)] (SUCRA = 90.3%). Furthermore, rTMS, tRNS, and tDCS on certain areas may improve PwMS accuracy, response time, manual dexterity, pain relief and QOL, but does not show statistically significant differences. The evidence assessed using GRADE is very low.

CONCLUSION

Based on the NMA and SUCRA ranking, we can conclude that symptoms including fatigue, pain, spasticity, and QOL can be improved by following NIBS protocol after treatment. Nonetheless, most of the included studies lack a good methodology, and more high-quality randomized clinical trials are needed.