Cognitive fatigability is a quantifiable distinct phenomenon in multiple sclerosis

Effects of power training in older patients with multiple sclerosis on neurodegeneration, neuromuscular function, and physical function. A study protocol for the "power training in older multiple sclerosis patients (PoTOMS) randomized control trial

Introduction

Approximately one-third of all persons with multiple sclerosis (pwMS) are older, i.e., having an age ≥60 years. Whilst ageing and MS separately elicit deteriorating effects on brain morphology, neuromuscular function, and physical function, the combination of ageing and MS may pose a particular challenge. To counteract such detrimental changes, power training (i.e., a type of resistance exercise focusing on moderate-to-high loading at maximal intended movement velocity) presents itself as a viable and highly effective solution. Power training is known to positively impact physical function, neuromuscular function, as well as brain morphology. Existing evidence is promising but limited to young and middle-aged pwMS, with the effects of power training remaining to be elucidated in older pwMS.

Methods

The presented 'Power Training in Older MS patients (PoTOMS)' trial is a national, multi-center, parallel-group, randomized controlled trial. The trial compares 24 weeks of usual care(n = 30) to 24 weeks of usual care and power training (n = 30). The primary outcome is whole brain atrophy rate. The secondary outcomes include changes in brain micro and macro structures, neuromuscular function, physical function, cognitive function, bone health, and patient-reported outcomes.

Ethics and dissemination

The presented study is approved by The Regional Ethics Committee (reference number 1-10-72-222-20) and registered at the Danish Data Protection Agency (reference number 2016-051-000001). All study findings will be published in scientific peer-reviewed journals and presented at relevant scientific conferences independent of the results. The www.clinicaltrials.gov identifier is NCT04762342.

Fatigue and cognitive fatigability in patients with chronic pain

OBJECTIVES

Fatigue is common in patients with chronic pain. Still, there is a lack of studies examining objectively measurable cognitive aspects of fatigue: cognitive fatigability (CF). We aimed to investigate the presence of CF in patients with chronic pain and its relation to self-rated fatigue, attention, pain characteristics, sleep disturbance, depression, and anxiety.

METHODS

Two hundred patients with chronic pain and a reference group of 36 healthy subjects underwent a comprehensive neuropsychological test battery, including measurement of CF with the Wechsler Adult Intelligence Scale-III Coding subtest, and self-assessment of trait and state fatigue.

RESULTS

The patients with chronic pain did not show more CF as compared to the reference group. There was an association between CF and processing speed on a test of sustained and selective attention in the chronic pain group, while self-rated fatigue measures and pain characteristics were not associated with CF. Self-rated fatigue measures were highly correlated with self-rated pain intensity, spreading of pain, depression, anxiety, and sleep disturbance.

CONCLUSIONS

The findings highlight the distinction between objective and subjective aspects of fatigue in chronic pain, and that the underlying causes of these different aspects of fatigue need to be studied further.

Slowing processing speed is associated with cognitive fatigue in newly diagnosed multiple sclerosis patients

OBJECTIVE

To further investigate objective measures of cognitive fatigue (CF), defined as the inability to sustain performance over time, in newly diagnosed multiple sclerosis (MS) patients, by conducting a performance analysis on the Paced Auditory Serial Addition Test (PASAT) based on the type of errors (omissions vs. incorrect responses) committed.

METHOD

Sixty-two newly diagnosed patients with MS (pwMS) and 41 healthy controls (HC) completed the PASAT. Analysis of the change in performance during the test was performed by comparing the number of correct responses, incorrect responses, and omissions in the 1^st versus the 3^rd tertile of the PASAT.

RESULTS

A significant decline in accuracy over time was observed to be related to an increment in the number of omissions, significantly more pronounced in pwMS than in HC. No change in the number of incorrect responses throughout the PASAT was observed for either group.

CONCLUSIONS

CF can be detected even in newly diagnosed pwMS and might objectively manifest as a progressive increase in omissions during a sustained highly demanding task (i.e., PASAT). This pattern may reflect slowed processing speed and increased fatigue in pwMS. Focusing on omissions on the PASAT instead of correct responses only may improve its specificity as an objective measure of CF.

Fatigue and Human Performance: An Updated Framework

Fatigue has been defined differently in the literature depending on the field of research. The inconsistent use of the term fatigue complicated scientific communication, thereby limiting progress towards a more in-depth understanding of the phenomenon. Therefore, Enoka and Duchateau (Med Sci Sports Exerc 48:2228-38, 2016, [3]) proposed a fatigue framework that distinguishes between trait fatigue (i.e., fatigue experienced by an individual over a longer period of time) and motor or cognitive task-induced state fatigue (i.e., self-reported disabling symptom derived from the two interdependent attributes performance fatigability and perceived fatigability). Thereby, performance fatigability describes a decrease in an objective performance measure, while perceived fatigability refers to the sensations that regulate the integrity of the performer. Although this framework served as a good starting point to unravel the psychophysiology of fatigue, several important aspects were not included and the interdependence of the mechanisms driving performance fatigability and perceived fatigability were not comprehensively discussed. Therefore, the present narrative review aimed to (1) update the fatigue framework suggested by Enoka and Duchateau (Med Sci Sports Exerc 48:2228-38, 2016, [3]) pertaining the taxonomy (i.e., cognitive performance fatigue and perceived cognitive fatigue were added) and important determinants that were not considered previously (e.g., effort perception, affective valence, self-regulation), (2) discuss the mechanisms underlying performance fatigue and perceived fatigue in response to motor and cognitive tasks as well as their interdependence, and (3) provide recommendations for future research on these interactions. We propose to define motor or cognitive task-induced state fatigue as a psychophysiological condition characterized by a decrease in motor or cognitive performance (i.e., motor or cognitive performance fatigue, respectively) and/or an increased perception of fatigue (i.e., perceived motor or cognitive fatigue). These dimensions are interdependent, hinge on different determinants, and depend on body homeostasis (e.g., wakefulness, core temperature) as well as several modulating factors (e.g., age, sex, diseases, characteristics of the motor or cognitive task). Consequently, there is no single factor primarily determining performance fatigue and perceived fatigue in response to motor or cognitive tasks. Instead, the relative weight of each determinant and their interaction are modulated by several factors.

Development of a behavioural intervention for cognitive fatigability in multiple sclerosis: Protocol for a pilot and feasibility study

Background

Up to 90% of people with multiple sclerosis (PwMS) subjectively report fatigue as one of their worst symptoms. Fatigability is an objectively measured component of fatigue. Cognitive fatigability (CF) is a breakdown in task performance following sustained cognitive effort. There is a paucity of interventions targeting CF in MS. The prior success of behavioural interventions at improving subjective fatigue suggests that their adaptation may yield similar results for CF. Given the relationship between CF, sleep quality, and mood, a behavioural intervention targeting these factors, such as cognitive behavioural therapy (CBT), is warranted. Given the multidimensional nature of fatigue, a multifaceted approach targeting lifestyle factors and coping (e.g., fatigue management education supplemented by CBT for insomnia and exercise) might prove efficacious.

Aim

We describe a protocol for a pilot feasibility study to design and implement a multi-dimensional behavioural intervention to improve CF in PwMS.

Methods

Stage 1: development of a multi-dimensional group-based videoconference-delivered behavioural intervention based on a previously successful fatigue management program for PwMS. A facilitator manual will be drafted. Course material will focus on four themes: body (sleep and physical activity), mood (impact of depression and anxiety), mind (cognitive contributions), and context (pacing and communication). Stage 2: a needs assessment survey will be completed by 100 PwMS for input on what factors are important contributors to their CF. Modifications will be made to the course material and manual. Stage 3: the facilitator-delivered intervention will include 20 PwMS. After baseline assessment, participants will attend weekly 70-min videoconference group sessions for 8 weeks, including homework assignments. Follow-up assessment will re-evaluate outcomes. Stage 4: analysis and dissemination of results. The primary outcome is improvement in CF. Additional feasibility outcomes will determine if a randomized control trial (RCT) is pursued. Stage 5: refine the intervention based on outcomes and feedback from participants. Determining which aspects participants felt were most effective will help inform RCT design.

Conclusion

The long-term goal is to ensure that PwMS have access to effective interventions in real-world settings to improve quality of life and enhance their ability to participate in cognitively demanding activities that they enjoy.

Italian translation and validation of fatigue symptoms and impacts questionnaire in relapsing multiple sclerosis (FSIQ-RMS)

BACKGROUND

Fatigue is a disabling symptom of multiple sclerosis (MS) and impacts on daily life. The Fatigue Symptoms and Impacts Questionnaire-Relapsing Multiple Sclerosis (FSIQ-RMS) is a new 20-item tool that investigates the aspects of fatigue in MS. It concerns motor, cognitive, social, and emotional aspects of fatigue. We aim at validating the Italian version of FSIQ-RMS in an Italian population of MS patients and demonstrate its reliability and construct validity.

METHODS

We included patients with diagnosis of MS, age between 18 and 70 years with ability to participate in a 90-min interview. Each patient completed the Italian version of FSIQ-RMS and Fatigue Severity Scale (FSS) at the same time. Construct validity was explored by the exploratory factor analysis; reliability was assessed with Cronbach's alpha; and test-retest stability was examined through intraclass correlation coefficient (ICC). Concurrent validity was calculated using Pearson's correlation.

RESULTS

We enrolled 171 patients (126 female and 45 male), 83% with relapsing MS (RMS), and 17% with secondary progressive MS (SPMS). Italian FSIQ-RMS showed a Cronbach's alpha of 0.92; ICC was 0.96. Pearson's correlation coefficient between FSIQ-RMS and FSS total score was statistically significant (p < 0.01); FSIQ-RMS inversely correlated also with BMI and positively with EDSS.

CONCLUSION

The Italian version of FSIQ-RMS has excellent psychometric properties and can be used in research and clinical setting to evaluate physical, cognitive, and social fatigue in both RMS and SPMS.

Effects of a 6-Min Treadmill Walking Test on Dual-Task Gait Performance and Prefrontal Hemodynamics in People With Multiple Sclerosis

Fatigue is one of the most limiting symptoms in people with multiple sclerosis (pwMS) and can be subdivided into trait and state fatigue. Activity-induced state fatigue describes the temporary decline in motor and/or cognitive performance (motor and cognitive performance fatigability, respectively) and/or the increase in the perception of fatigue (perceived fatigability) in response to motor or cognitive tasks. To the best of our knowledge, the effects of a 6-min walk test (6MWT), which was often used to assess motor performance fatigability in pwMS, on motor-cognitive dual-task performance (i.e., walking + arithmetic task) and prefrontal cortex (PFC) hemodynamics are not well-known. This is of importance, since daily activities are often performed as multitasks and a worse dual-task walking performance is associated with an increased risk of falling. Consequently, we investigated the effect of a fast 6MWT (comfort velocity + 15%) performed on a treadmill on motor-cognitive performance fatigability (spatio-temporal gait parameters/accuracy during the arithmetic task) and perceived fatigability measures (rating of perceived exhaustion; RPE) as well as PFC hemodynamics recorded during dual-task walking in pwMS and healthy controls (HCs). Twenty pwMS (48.3 ± 9.0 years; 13 females/7 males; expanded disability status scale 2.7 ± 1.0, first diagnosis 13.8 ± 8.8 years) and 24 HC with similar age and sex (48.6 ± 7.9 years; 17 females/7 males) were included. Only cognitive performance fatigability (increased error rate) during dual-task walking was found after the fast 6MWT on the treadmill in pwMS. However, the changes in gait parameters did not indicate motor performance fatigability, although both the groups reported perceived fatigability (increased RPE) after the fast 6MWT. Moreover, no change in the PFC activation was detected in both groups. Our results suggest that the intensity and/or duration of the fast 6MWT was not sufficient to induce motor performance fatigability in pwMS. These factors should be addressed by future studies on this topic, which should also consider further parameters, e.g., muscular oxygenation and/or myoelectrical activity, to verify that exercise intensity and/or duration was appropriate to induce motor performance fatigability in pwMS.