Systematically developed pilot randomized controlled trial of exercise and cognition in persons with multiple sclerosis

Impact of physical activity, physical fitness and exercises on cognitive impairment in patients with multiple sclerosis: A review of evidence and underlying mechanisms

Cognitive impairment in persons with MS (pwMS) occurs commonly, early and independently of other clinical features of the disease. MS-related cognitive impairment is mainly characterized by weakening of information processing speed, working memory and episodic memory. Much evidence, based on both neuropsychological and neuroimaging outcomes, highlights successful cognitive rehabilitation interventions. In this context, promotion of physical activity and exercise training could be a dual, motor and cognitive, rehabilitation method. The aim of this article is, firstly, to review existing evidence regarding the effects of exercise on cognition among pwMS, and secondly, to explore the possible mechanisms of action of the cognitive-motor coupling.

Effects of walking interventions in persons with multiple sclerosis-A systematic review

OBJECTIVE

The aim of the present systematic review was to investigate the effects of voluntary walking interventions in persons with multiple sclerosis (pwMS). For this purpose, we developed a framework to describe the components of walking interventions.

DATA SOURCES

Two databases (MEDLINE/PubMed and EMBASE) were searched in January 2023.

STUDY SELECTION

Included studies enrolled pwMS and evaluated walking interventions with a duration of 2 weeks or longer. Further, they evaluated at least one walking-related outcome. Both RCTs and non-controlled studies were enrolled.

DATA EXTRACTION

Data were extracted using a customized spreadsheet, which included detailed information on patient characteristics, interventions, outcomes, and results. Based on the extracted results, the effect sizes (ES, Hedge's g) of the walking interventions were calculated if possible. The methodological quality of the included studies and their reporting was determined using the TESTEX evaluation tool.

DATA SYNTHESIS

Data from a total of n = 200 pwMS was included from N = 7 RCT´s (from 3 we used within-group data) and N = 5 single-group studies. On average 91.7 ± 9.9 % of the planned walking sessions were attended, 8.7 ± 10.5 % of the participants dropped out, and very few adverse events occurred. Walking interventions improved walking performance during short distance walk tests (ES ranging from -0.21 to -0.72, "walking time") and long distance walk tests (ES ranging from 0.27 to 0.72, "walking distance").

CONCLUSIONS

Voluntary walking interventions appear to be safe and effective at improving walking performance in pwMS. However, well-powered walking intervention studies are needed to confirm these promising effects. The simplicity of walking interventions makes them highly relevant for ambulatory pwMS.

Leveraging Emerging Technologies to Expand Accessibility and Improve Precision in Rehabilitation and Exercise for People with Disabilities

Physical rehabilitation and exercise training have emerged as promising solutions for improving health, restoring function, and preserving quality of life in populations that face disparate health challenges related to disability. Despite the immense potential for rehabilitation and exercise to help people with disabilities live longer, healthier, and more independent lives, people with disabilities can experience physical, psychosocial, environmental, and economic barriers that limit their ability to participate in rehabilitation, exercise, and other physical activities. Together, these barriers contribute to health inequities in people with disabilities, by disproportionately limiting their ability to participate in health-promoting physical activities, relative to people without disabilities. Therefore, there is great need for research and innovation focusing on the development of strategies to expand accessibility and promote participation in rehabilitation and exercise programs for people with disabilities. Here, we discuss how cutting-edge technologies related to telecommunications, wearables, virtual and augmented reality, artificial intelligence, and cloud computing are providing new opportunities to improve accessibility in rehabilitation and exercise for people with disabilities. In addition, we highlight new frontiers in digital health technology and emerging lines of scientific research that will shape the future of precision care strategies for people with disabilities.

Effect of different types of exercise on fitness in people with multiple sclerosis: A network meta-analysis

BACKGROUND

It is assumed that people with multiple sclerosis (MS) who participate in programs of physical exercise improve their physical fitness.

OBJECTIVE

The aim of this network meta-analysis (NMA) was to analyze the effect of different types of exercise on muscular fitness and cardiorespiratory fitness (CRF) among people with MS and to determine the best type of exercise according to disease severity.

METHODS

MEDLINE, the Physiotherapy Evidence Database, the Cochrane Library, SPORTDiscus, Scopus, and Web of Science were searched from inception to April 2022 to identify randomized controlled trials (RCTs) concerning the effect of physical exercise on fitness in people with MS. We ranked the types of physical exercise by calculating the surface under the cumulative ranking (SUCRA).

RESULTS

We included 72 RCTs involving 2543 MS patients in this NMA. A ranking of five types of physical exercise (aerobic, resistance, combined [aerobic and resistance], sensorimotor training, and mind-body exercises) was achieved. Combined and resistance training had the highest effect sizes (0.94, 95% CI 0.47, 1.41, and 0.93, 95% CI 0.57, 1.29, respectively) and the highest SUCRA (86.2% and 87.0%, respectively) for muscular fitness. The highest effect size (0.66, 95% CI 0.34, 0.99) and SUCRA (86.9%) for CRF was for aerobic exercise.

CONCLUSIONS

Combined and resistance training seem to be the most effective exercises to improve muscular fitness and aerobic exercise for CRF in people with MS.

Complexity and pitfalls in maximal exercise testing for persons with multiple sclerosis

BACKGROUND AND PURPOSE

Valid measurements of cardiorespiratory fitness in persons with multiple sclerosis (pwMS) are essential during inpatient rehabilitation for a precise evaluation of the current health status, for defining appropriate exercise intensities, and for evaluation of exercise intervention studies. We aim (i) to examine the proportion of pwMS who attain the American College of Sports Medicine (ACSM) criteria for maximal effort during graded cardiopulmonary exercise testing (CPET) and (ii) to provide insight into participant characteristics that limit maximal exercise performance.

METHODS

This cross-sectional study comprises a retrospective examination of ACSM criteria for maximal effort during graded CPET of n = 380 inpatient pwMS (mean age = 48 ± 11 years, 66% female). Chi-squared or Fisher's exact tests were conducted to compare differences in the distribution of criteria achieved. Participants' characteristics were examined as potential predictors using binary logistic regression.

RESULTS

Only 60% of the overall sample attained a respiratory exchange ratio ≥ 1.10. With regard to the definition applied, only 24% or 40% of the participants achieved an oxygen consumption plateau, and 17% or 50% attained the heart rate criterion. Forty-six percent met at least two of three criteria. Disability status, gender, disease course, and body mass index were associated with the attainment of maximal effort.

CONCLUSIONS

Our findings suggest that a relevant proportion of inpatient pwMS do not attain common criteria utilized to verify maximal oxygen consumption. Identified predictors for criteria attainment can be used to create models to predict cardiorespiratory fitness and to optimize CPET protocols in restrictive groups of pwMS.

Feasibility of remotely delivered and supported aerobic walking exercise training for cognitive processing speed impairment in fully-ambulatory persons with multiple sclerosis

PURPOSE

The current pilot, single-blind, randomized controlled trial (RCT) examined the feasibility of remotely-delivered and supported aerobic walking exercise training compared with an active control condition on cognitive processing speed (CPS) in 19 fully-ambulatory persons with multiple sclerosis (pwMS) who were pre-screened for impaired CPS.

METHODS

Feasibility was assessed in the domains of process (e.g., recruitment), resource (e.g., monetary costs), management (e.g., time requirements), and scientific outcomes (i.e., treatment effect). Fully-ambulatory, but CPS-impaired pwMS were randomly assigned into either 16-weeks of home-based aerobic walking exercise or home-based stretching and range-of-motion activities. Both conditions involved delivery of informational newsletters and one-on-one, online video chats with a behavior coach. Participants across both conditions tracked their activity using highly accurate wearable motion sensors. Treatment-blinded assessors administered the Symbol Digit Modalities Test (SDMT) remotely before and after the 16-week study period.

RESULTS

The study was cost-effective, accessible, and acceptable. The intervention further was safe. Adherence and compliance rates across both conditions exceeded 80%. There was an overall moderate effect for change in SDMT score between the conditions (d = 0.42). The intervention was associated with a 4.8-point improvement in SDMT scores (d = 0.70; 10% increase) compared with a 1-point improvement for the control condition (d = 0.09; 2% increase).

CONCLUSIONS

This remotely-delivered and supported aerobic walking exercise training intervention was safe and feasible for fully-ambulatory, CPS-impaired pwMS. The pattern of results, including the promising effects on CPS, support the design and implementation of an appropriately-powered RCT on this approach for managing CPS impairment in a large MS sample.

The effect of exercise on cognitive function in people with multiple sclerosis: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

A growing body of research examining the effect of exercise on cognitive function in people with multiple sclerosis (MS), while findings of available studies were conflicting. We aimed to explore the effect of exercise on cognitive function in MS patients.

METHODS

For this systematic review and meta-analysis, we searched PubMed, Web of Science, EBSCO, Cochrane, and Scopus electronic databases, through July 18, 2022. Cochrane risk assessment tool was used to evaluate the methodological quality of the included literature.

RESULTS

Twenty-one studies with a total of 23 experimental groups and 21 control groups met the inclusion criteria. There was a significant effect of exercise on improving cognitive function in MS patients, while the effect size was small (Cohen's d = 0.20, 95% CI 0.06-0.34, p < 0.001, I² = 39.31%). Subgroup analysis showed that exercise significantly improved memory (Cohen's d = 0.17, 95% CI 0.02-0.33, p = 0.03, I² = 7.59%). In addition, multicomponent training, exercise conducted 8 weeks and 10 weeks, up to 60 min per session, 3 times or more per week, 180 min or more per week increased cognitive function significantly. Furthermore, a worse basal MS status (defined by the Expanded Disability Status Scale) and an older age were associated with greater improvement in cognitive function.

CONCLUSION

MS patients are recommended to participate in at least three multicomponent training sessions per week, with each session lasting up to 60 min, and the exercise goal of 180 min per week can be achieved by increasing the frequency of exercise. Exercise lasting 8 or 10 weeks is best for cognitive function improvement. Additionally, a worse basal MS status, or the older the age, the greater effect on cognitive function.

Upper-lower limb and breathing exercise program for improving sleep quality and psychological status in multiple sclerosis: a pilot randomized controlled trial

PURPOSE

To examine the feasibility and possible effect of an 8-week exercise program on sleep quality, insomnia and psychological distress in individuals with multiple sclerosis (MS).

METHODS

Twenty-four individuals with MS were recruited into a controlled pre-post feasibility study and divided into 2 groups: exercise (n = 13; Expanded Disability Status Scale (EDSS): 1.0-7.5) and a related control group with no exercise (n = 11; EDSS: 1.0-7.0). The exercise group performed combined upper limb, lower limb and breathing exercises in a controlled group (2d/week, 60 min/session) for 8 weeks. Participants were administered measures to evaluate sleep quality (Pittsburgh Sleep Quality Index, PSQI), insomnia severity (Insomnia Severity Index, ISI), psychological distress (Clinical Outcomes in Routine Evaluation-Outcome Measure, CORE-OM) and additionally impact of fatigue (Modified Fatigue Impact Scale, MFIS) after 8-weeks.

RESULTS

Insomnia severity measured with ISI (F(1;22)=5.95, p = 0.023, η p 2 = 0.213, 90% CI = 0.02-0.42) and psychological distress measured with the CORE-OM (F(1;22)=4.82, p = 0.039, η p 2 = 0.179, 90% CI = 0.01-0.40) showed statistically significant group-by-time interaction. Sleep quality measured with the PSQI showed statistically significant group-by-time interaction only in an aspect of daytime sleep dysfunction (F(1;22)=5.33, p = 0.031, η p 2 = 0.195, 90% CI = 0.01-0.40). The fatigue impact measured with the MFIS showed statistically significant group-by-time interaction in physical (F(1;22)=6.80, p = 0.016, η p 2 = 0.236, 90% CI = 0.02-0.44) and cognitive aspects (F(1;22)=9.12, p = 0.006, η p 2 = 0.293, 90% CI = 0.05-0.49), and total score (F(1;22)=11.29, p = 0.003, η p 2 = 0.339, 90% CI = 0.08-0.52).

CONCLUSIONS

Our 8-week program reduced insomnia severity, psychological distress and some aspects of fatigue (physical; cognitive; total), and improved sleep quality in an aspect of daytime sleep dysfunction in a small group of individuals with MS. Good feasibility and significant positive changes from baseline warrant further exploratory work.

Repeated forms, testing intervals, and SDMT performance in a large multiple sclerosis dataset

BACKGROUND

The Symbol Digit Modalities Test (SDMT), the most reliable and sensitive measure of cognition in people with multiple sclerosis (PwMS), is increasingly used in clinical trials and care.

OBJECTIVES

We aimed to establish how SDMT performance is influenced by repeating forms and frequency of use in PwMS.

METHODS

A retrospective analysis was completed on a large database of PwMS (n = 740) with multiple SDMT administrations. Change in SDMT performance was analyzed, accounting for frequency of tests and utilization of alternate- versus same-form conditions.

RESULTS

SDMT administrations ranged from 2 to 14 per subject over a mean (SD) of 5.9 (4.5) years. Accounting for demographics, the mixed effects model revealed a significant main effect of SDMT exposures (1.8 point improvement per repetition, p = 0.001) and an interaction between time since previous SDMT and whether the same test form was administered in the previous administration (estimate=-1.1, p = 0.037). As well, SDMT decline is observed when testing intervals exceed two years (F = 9.69, p<0.001).

CONCLUSION

Improvements in SDMT performance with repeated exposure, likely reflecting practice effects, were greatest when repeating the same SDMT form over briefer intervals. We recommend the use of alternate forms or analogous versions of timed symbol-digit coding particularly where samples are saturated with many administrations.

Participant characteristics of existing exercise studies in persons with multiple sclerosis - A systematic review identifying literature gaps

BACKGROUND

Exercise is a cornerstone in rehabilitation of persons with multiple sclerosis (pwMS), which is known to elicit beneficial effects on various symptoms and to have a potential disease-modifying effect. However, it remains to be elucidated if the existing MS exercise literature covers the full age and disability span of pwMS.

OBJECTIVE

To systematically review MS exercise studies and provide a detailed mapping of the demographic and clinical characteristics of the included pwMS.

METHODS

A systematic review of MS exercise studies were performed using MEDLINE and EMBASE. From the resulting MS exercise studies, mean sample characteristics were extracted.

RESULTS

4576 records were identified, from which 202 studies were included. Of these, 166 studies (82.2%) enrolled pwMS aged 35-54 years, 10.9% enrolled pwMS <35 years, and 6.9% enrolled pwMS ≥55 years (only 1.5% enrolled pwMS ≥60 years). A total of 118 studies (58.4%) reported Expanded Disability Status Scale (EDSS), with 88.1% of included pwMS having an EDSS between 2.0 and 6.5, while only one study enrolled pwMS with an EDSS ≥7.0. Finally, 80% of the studies included pwMS having a disease duration of 5-14.5 years.

CONCLUSION

Exercise studies in pwMS included primarily middle-aged (35-54 years) pwMS having an EDSS of 2.0-6.5 and a disease duration of 5-14.5 years. Few exercise studies were identified in young and older pwMS, in pwMS with mild disability and severe disability, and in pwMS having shorter or longer disease durations. These findings highlight the need for further investigation of exercise in these specific subgroups of pwMS as benefits of exercise might not generalize across subpopulations.

IL-6 and TNF-α responses to acute and regular exercise in adult individuals with multiple sclerosis (MS): a systematic review and meta-analysis

Background

In both the general population and people with multiple sclerosis (PwMS), physical exercise is associated with improved mental well-being. Moreover, there is evidence of the possible protection of physical activity against disease progression in multiple sclerosis (MS). However, the question arises if acute or regular exercise has any impact on the immune system in PwMS. To answer this question, we performed a systematic review and meta-analysis on both plasma and serum cytokine levels (IL-6 and TNF-α) before and after acute and regular exercise among PwMS and compared to healthy controls.

Method

We performed an online search via PubMed, EMBASE, SCOPUS, Web of Science, and Cochrane Library till September 2021 to identify original studies on IL-6 and TNF-α changes after acute and regular exercise in PwMS and controls. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), 11 original studies were included in the meta-analysis. Sensitivity analyses were used to identify the origins of heterogeneity. R 4.0.4 was used to perform the meta-analysis of IL-6 and TNF-α levels before and after acute and regular exercise in PwMS, compared to controls. This study does not qualify for a clinical trial number.

Results

IL-6 levels did neither increase nor decrease after acute and regular exercise in PwMS, and compared to controls (pre- vs. post-intervention: Standardized Mean Difference (SMD) -0.09, 95% CI [−0.29; 0.11], p-value = 0.37, PwMS vs. Control: SMD −0.08, 95% CI [−0.33; 0.16], p-value = 0.47). In PwMS, TNF-α levels decreased after regular exercise and when TNF-α levels of both acute and regular exercise were pooled (pre- vs. post-intervention: SMD −0.51, 95% CI [-0.91; 0.11], p-value = 0.01, PwMS vs. Control: SMD −0.23, 95% CI [−0.66; 0.18], p-value = 0.26). TNF-α levels did neither increase nor decrease after acute and regular exercise in PwMS, when compared to controls.

Conclusion

This systematic review and meta-analysis show that exercise does not lead to significant changes in peripheral levels of IL-6 in PwMS in contrast to the observed response in healthy subjects and other medical contexts. However, regular exercise had a specific anti-inflammatory effect on blood TNF-α levels in PwMS. It remains to be investigated why PwMS display this different exercise-induced pattern of cytokines.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40001-022-00814-9.

Exercise-induced increase in blood-based brain-derived neurotrophic factor (BDNF) in people with multiple sclerosis: A systematic review and meta-analysis of exercise intervention trials

Background

Exercise training may affect the blood levels of brain-derived neurotrophic factor (BDNF), but meta-analyses have not yet been performed comparing pre- and post-intervention BDNF concentrations in patients with multiple sclerosis (PwMS).

Objective

To perform a meta-analysis to study the influence of exercise on BDNF levels and define components that modulate them across clinical trials of exercise training in adults living with multiple sclerosis (MS).

Method

Five databases (PubMed, EMBASE, Cochrane Library, PEDro database, CINAHL) were searched up to June 2021. According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, we included 13 articles in the meta-analysis, including 271 subjects. To investigate sources of heterogeneity, subgroup analysis, meta-regression, and sensitivity analysis were conducted. We performed the meta-analysis to compare pre- and post-exercise peripheral levels of BDNF in PwMS.

Results

Post-exercise concentrations of serum BDNF were significantly higher than pre-intervention levels (Standardized Mean Difference (SMD): 0.33, 95% CI: [0.04; 0.61], p-value = 0.02). Meta-regression indicated that the quality of the included studies based on the PEDro assessment tool might be a source of heterogeneity, while no significant effect was found for chronological age and disease severity according to the expanded disability status scale.

Conclusion

This systematic review and meta-analysis shows that physical activity increases peripheral levels of BDNF in PwMS. More research on the effect of different modes of exercise on BDNF levels in PwMS is warranted.

Systematic Review of Exercise Studies in Persons with Multiple Sclerosis: Exploring the Quality of Interventions According to the Principles of Exercise Training

INTRODUCTION

The objective of this systematic review is to explore the application and reporting of (i) the principles of exercise training in exercise trials, (ii) the components of exercise prescription, and (iii) the adherence towards the prescribed programmes in randomised controlled trials (RCTs) in persons with multiple sclerosis (pwMS).

METHODS

The MEDLINE, CINAHL, SPORTDiscus, PubMed and Embase electronic databases were searched from 1 January 2000 to 16 October 2020. RCTs comprising at least 3 weeks of aerobic and/or resistance exercise intervention in pwMS that reported at least one physiological outcome and were published in peer-reviewed journals were eligible for inclusion.

RESULTS

Out of 52 RCTs included in this review, 58 intervention arms were examined. None applied more than four principles of exercise training. Specificity was addressed by 85%, progression by 33%, overload by 59%, initial values by 26%, reversibility by 0% and diminishing returns by 2% of trials. Fifty-two percent of trials reported all components of exercise prescription, and 3% of trials reported the level of adherence to the prescribed exercise.

CONCLUSION

This systematic review reveals that exercise training principles were not respected in the majority of included RCTs. The weak quality of reported exercise interventions limits the interpretation of the studies' results and potentially leads to an underestimation of 'exercise as medicine' in pwMS. Also, the vague descriptions of exercise prescription and adherence impede the reproducibility of results. Future studies must attend to all principles of exercise training and provide transparent information on the prescribed and performed programmes to develop specific and valid exercise recommendations for pwMS.

SYSTEMATIC REVIEW REGISTRATION

CRD42020162671, 28/04/2020, PROSPERO.

Functional connectivity pre-post exercise intervention in individuals with relapsing-remitting multiple sclerosis

OBJECTIVE

Exercise interventions have emerged as a promising approach for managing symptoms associated with multiple sclerosis (MS). However, changes in brain function underlying exercise-related improvements in symptoms of MS have not been fully investigated, and in no instances have they been investigated using a graph theory approach. For the first time, the effects of an exercise intervention on functional brain network connectivity were examined using graph theory analyses of resting-state functional MRI (fMRI) data among individuals with relapsing-remitting MS (RRMS).

METHODS

Resting-state fMRI data were obtained from 10 participants before and after 12 weeks of a speeded walking intervention. Functional connectivity data were preprocessed in Data Processing Assistant for Resting-State fMRI Advanced (DPARSF A version 4.2) and analyzed in GraphVar2.02 to compute global and local graph theory metrics. To examine differences in graph metrics before and after the intervention, one-sample permutation tests were performed.

RESULTS

There were no significant pre to post exercise intervention changes in global metrics. Changes in local metrics (i.e. clustering coefficient, local efficiency, degree centrality and betweenness centrality) were mixed, with both increases and decreases observed.

CONCLUSION

Following a 12-week speeded walking exercise intervention, there were no significant increases or decreases in global graph metrics and results at the level of local metrics were equivocal in individuals with RRMS. Further research with experimental designs that include baseline and longitudinal follow-up, as well as larger sample sizes, is needed to understand the underlying mechanisms of symptom improvement following exercise in RRMS.

Effects of walking exercise training on learning and memory and hippocampal neuroimaging outcomes in MS: A targeted, pilot randomized controlled trial

PURPOSE

The current pilot study involved a single-blind, randomized controlled trial (RCT) on the effects of treadmill walking exercise training compared with an active control condition on learning and memory (L/M) and hippocampal neuroimaging outcomes in 11 fully-ambulatory persons with multiple sclerosis (MS) who demonstrated impairments in new learning.

METHODS

The study protocol is registered at clinicaltrials.gov: NCT03319771 (February 2018). Eleven fully-ambulatory persons with MS-related impairments in new learning were randomly assigned into either 12-weeks of supervised, treadmill walking exercise training or 12-weeks of low-intensity resistive exercise (active control condition). Participants underwent neuropsychological tests of L/M and hippocampal neuroimaging before and after the 12-week study period; outcomes were administered by treatment-blinded assessors.

RESULTS

There were moderate-to-large intervention effects on measures of verbal L/M (η_p² = 0.11, d = 0.63, 95% CI: -0.61, 1.83), whereby those in the intervention condition demonstrated improvement in California Verbal Learning Test-II (CVLT-II) scores compared with the control condition. There were smaller effects on a composite L/M measure (η_p² = 0.02, d = 0.28, 95% CI: -0.93, 1.46). There were large intervention effects on normalized hippocampal volume (η_p² = 0.36, d = 1.13, 95% CI: 0.09, 2.82), whereby hippocampal volume was preserved in the intervention condition, compared with hippocampal atrophy in the control condition. By comparison, there were no intervention effects on hippocampal resting-state functional connectivity.

CONCLUSIONS

Collectively, this study provides initial proof-of-concept data for further examining treadmill walking exercise training as a possible behavioral approach for managing L/M impairment and preserving hippocampal volume as common and debilitating manifestations of MS.

Aerobic reserve capacity in multiple sclerosis-Preliminary evidence

OBJECTIVES

Aerobic reserve capacity reflects the available energy for performing everyday life tasks, and it has been studied in older adult populations. This preliminary study examined proof of concept and measurement of aerobic reserve capacity in multiple sclerosis (MS).

MATERIALS & METHODS

Twenty-one fully ambulatory people with MS performed a maximal, cardiopulmonary exercise test (CPET). We calculated aerobic reserve capacity based on the difference between peak aerobic power (VO_2peak ) and first stage oxygen consumption (VO₂ ). Participants completed assessments for disability (Expanded Disability Status Scale, EDSS), cognition (Symbol Digit Modalities Test, SDMT), mood (Beck Depression Inventory, BDI), walking endurance (six-minute walk distance, 6MWD), walking speed (Timed Twenty-Foot Walk, T25FW), impact of MS (Multiple Sclerosis Impact Scale, MSIS-29), and anthropometric measurements (height and weight).

RESULTS

Aerobic reserve capacity was 9.3 ± 3.7 ml/kg/min. Aerobic reserve capacity was positively associated with VO_2peak (ρ = .67, p < .01), time to exhaustion (ρ = .63, p < .01), and SDMT (ρ = .51, p < .05). Aerobic reserve capacity was negatively associated with BMI (ρ = -.62, p < .01) and RHR (ρ = -0.47, p < .05).

CONCLUSION

We provide preliminary evidence that aerobic reserve capacity is a feasible outcome derived from maximal CPET (eg, modified Balke protocol) in MS. Aerobic reserve capacity was associated with clinically relevant outcomes and could become an important outcome for rehabilitation in future research.

A pilot randomized controlled trial of robotic exoskeleton-assisted exercise rehabilitation in multiple sclerosis

BACKGROUND

Co-occurring mobility and cognitive impairments are common, debilitating, and poorly-managed with pharmacological therapies in persons with multiple sclerosis (MS). Exercise rehabilitation (ER), particularly walking ER, has been suggested as one of the best approaches for managing these manifestations of MS. However, there is a focal lack of efficacy of ER on mobility and cognitive outcomes in persons with MS who present with substantial neurological disability. Such severe neurological disability oftentimes precludes the ability for participation in highly-intensive and repetitive ER that is necessary for eliciting adaptations in mobility and cognition. To address such a concern, robotic exoskeleton-assisted ER (REAER) might represent a promising intervention approach for managing co-occurring mobility and cognitive impairments in those with substantial MS disability who might not benefit from traditional ER.

METHODS

The current pilot single-blind, randomized controlled trial (RCT) compared the effects of 4-weeks of REAER with 4-weeks of conventional gait training (CGT) as a standard-of-care control condition on functional mobility (timed up-and-go; TUG), walking endurance (six-minute walk test; 6MWT), cognitive processing speed (CPS; Symbol Digit Modalities Test; SDMT), and brain connectivity (thalamocortical resting-state functional connectivity (RSFC) based on fMRI) outcomes in 10 persons with substantial MS-related neurological disability.

RESULTS

Overall, compared with CGT, 4-weeks of REAER was associated with large improvements in functional mobility (η_p²=.38), CPS (η_p²=.53), and RSFC between the thalamus and ventromedial prefrontal cortex (η_p²=.72), but not walking endurance (η_p²=.01). Further, changes in RSFC were moderately associated with changes in TUG, 6MWT, and SDMT performance, respectively, whereby increased thalamocortical RSFC was associated with improved functional mobility, walking endurance, and CPS (|ρ|>.36).

CONCLUSION

The current pilot RCT provides initial support for REAER as an approach for improving functional mobility and CPS, perhaps based on adaptive and integrative central nervous system plasticity, namely increases in RSFC between the thalamus and ventromedial prefrontal cortex, in a small sample of persons with substantial MS disability. Such a pilot trial provides proof-of-concept data for the design and implementation of an appropriately-powered RCT of REAER in a larger sample of persons with MS who present with co-occurring impairments in both mobility and cognitive functioning.

A pilot study of the impact of an exercise intervention on brain structure, cognition, and psychosocial symptoms in individuals with relapsing-remitting multiple sclerosis

BACKGROUND

Despite pharmacological treatment, many individuals with multiple sclerosis (MS) continue to experience symptoms and medication side effects. Exercise holds promise for MS, but changes in brain structure following exercise have not been thoroughly investigated, and important cognitive and psychosocial variables are rarely primary outcomes. The aim of this pilot study was to investigate whether a 12-week exercise intervention would improve white matter integrity in the brain, or cognition, symptoms of fatigue, and depressed mood for individuals with relapsing-remitting MS (RRMS).

METHOD

Thirteen participants completed 12 weeks of speeded walking. Baseline and post-intervention testing included 3T diffusion tensor imaging (DTI) to assess white matter and neuropsychological testing to assess cognition, fatigue, and mood. Image pre-processing and analyses were performed in functional magnetic resonance imaging of the Brain Software Library.

RESULTS

Post-intervention, there were no significant changes in white matter compared to baseline. Post-intervention, individuals with RRMS performed significantly better on the Symbol Digit Modalities Test (SDMT), reported fewer perceived memory problems, and endorsed less fatigue. Performance was not significantly different on Trails or Digit Span, and there were no significant changes in reports of mood.

CONCLUSION

Although 12 weeks of speeded walking did not improve white matter integrity, exercise may hold promise for managing some symptoms of RRMS in the context of this study population.

Dosage and Effectiveness of Aerobic Training on Cardiorespiratory Fitness, Functional Capacity, Balance, and Fatigue in People With Multiple Sclerosis: A Systematic Review and Meta-Analysis

OBJECTIVES

To evaluate the benefits of aerobic training (AT) programs on cardiorespiratory fitness, functional capacity, balance, and fatigue in individuals with multiple sclerosis (MS) and to identify the optimal dosage of AT programs for individuals with MS via a systematic review with meta-analysis.

DATA SOURCES

Two electronic databases were searched until March 2020 (PubMed-Medline and Web of Science).

STUDY SELECTION

Studies examining the effect of AT program on cardiorespiratory fitness, functional capacity, balance, and fatigue were included.

DATA EXTRACTION

After applying the inclusion and exclusion criteria, we included 43 studies. A total sample of 1070 individuals with MS (AT group, n=680; control group, n=390) were analyzed.

DATA SYNTHESIS

The AT group demonstrated a significant increase in cardiorespiratory fitness (standardized mean difference [SMD], 0.29; P=.002), functional capacity (timed Up and Go Test: SMD, -1.14; P<.001; gait speed: SMD, -1.19; P<.001; walking endurance: SMD, 0.46; P<.001), and balance (SMD, 3.49; P<.001) after training. Fatigue perception also decreased (SMD, -0.45; P<.001). However, no significant differences were observed when compared with the control group in either cardiorespiratory fitness (SMD, 0.14; P=.19) or fatigue perception. Nevertheless, we observed significant differences between the AT and control groups in balance (P=.02), gait speed (P=.02), and walking endurance (P=.03), favoring the participants who performed AT. Regarding the subgroup analysis, no significant differences were observed between subgroups in any of the variables studied except for gait speed, for which a greater increase in posttraining was observed when the AT program applied the continuous method (χ²=7.75; P=.005) and the exercises were performed by walking (χ²=9.36; P=.002).

CONCLUSIONS

Aerobic training improves gait speed, walking endurance, and balance. Cardiorespiratory fitness and fatigue perception also improved after AT, but we found no differences with the control group. In addition, subgroup analysis suggested that training using continuous and walking methods could optimize gait speed.

Behavior Change Techniques in Physical Activity Interventions for Multiple Sclerosis

OBJECTIVE

To identify and summarize the behavior change techniques (BCTs) included in behavior change interventions for promoting physical activity in persons with multiple sclerosis (MS).

DATA SOURCES

PubMed, PsycINFO, Cumulative Index to Nursing and Allied Health Complete, Scopus, and Embase were initially searched in November 2019, and data extraction began in June 2020.

STUDY SELECTION

The inclusion criteria for studies were: adults older than 18 years with diagnosed MS, English language, clinical trial designs (ie, pre-post or randomized controlled trials), group or individual interventions, and home or community-based settings wherein physical activity was defined as a primary or secondary outcome. Exclusion criteria for studies included protocol manuscripts pending results, case studies, studies focused on populations with multiple chronic diseases, and interventions targeting multiple behaviors. Two researchers completed screening for study selection, and a third researcher served as a referee. Of the initially identified 8681 studies, 54 studies met selection criteria.

DATA EXTRACTION

Data extraction was completed by 3 researchers. Each article was coded by 2 of the 3 researchers, and a fourth researcher resolved discrepancies. Data extracted from each paper included study title, authors, country, year, sample size, study design, intervention details, physical activity outcomes, and BCTs.

DATA SYNTHESIS

Thirty-eight unique behavior change interventions were identified, and 53 of the 93 possible BCTs were included across the studies. The mean number of BCTs per study was 15, and studies and effect sizes across studies ranged from 0.04-1.49.

CONCLUSIONS

This review provides a comprehensive overview of BCTs as the active ingredients in behavior change interventions targeting physical activity in MS. Results from this study provide a compendium for future intervention development for increasing physical activity and improving overall health in MS.

Efficacy of high-intensity aerobic exercise on cognitive performance in people with multiple sclerosis: A randomized controlled trial

BACKGROUND

Cognitive impairment is highly prevalent in multiple sclerosis (MS). Progressive aerobic exercise (PAE) represents a promising approach toward preservation or even improvement of cognitive performance in people with MS (pwMS).

OBJECTIVE

To investigate the effects of PAE on the cognitive domains of information processing, learning and memory, and verbal fluency in pwMS.

METHODS

This randomized controlled trial included an exercise (n = 43, 24 weeks of supervised PAE, followed by self-guided physical activity) and a waitlist group (n = 43, 24 weeks of habitual lifestyle, followed by supervised PAE). Assessments included the Brief Repeatable Battery of Neuropsychological tests (BRB-N), self-reported mood, and cardiorespiratory fitness. Published reference data were used to compute Z-scores for BRB-N scores. Cognitive impairment was defined as one or more Z-scores ⩽ -1.5SD.

RESULTS

No between-group changes in the total group were observed in BRB-N scores following PAE. In the cognitively impaired subgroup (43% of the total group) the between-group point estimate suggested a potential clinical relevant improvement in the Symbol Digit Modalities Test (95% CI overlapping zero). Cardiorespiratory fitness increased in the total group and the cognitively impaired subgroup.

CONCLUSION

In the present representative MS group, 24 weeks of supervised PAE had no effect on any cognitive domain in the total group but potentially improved processing speed in the cognitively impaired subgroup.

Combined exercise training improves cognitive functions in multiple sclerosis patients with cognitive impairment: A single-blinded randomized controlled trial

BACKGROUND

Cognitive impairment is common in patients with multiple sclerosis (MS). The effects of different exercise trainings on cognitive functions in patients with MS are promising. However, the effects are not yet clear in MS patients with cognitive impairment. This study aimed to investigate the effect of combined exercise training on different cognitive functions in MS patients with cognitive impairment.

METHODS

Relapsing-remitting and mild disabled MS patients with cognitive impairment were randomly assigned to two groups: Exercise Group (EG, n:17) and the Control Group (CG, n:17). The EG received a combined exercise training consisting of aerobic and Pilates training in three sessions per week for 8 weeks while the CG performed the relaxation exercises at home. Cognitive functions, walking capacity, fatigue, mood, and quality of life were assessed at baseline and after eight weeks using the Brief Repeatable Battery of Neuropsychological Tests (BRB-N), Six-Minute Walk Test (6-MWT), Fatigue Impact Scale (FIS), Beck's Depression Inventory (BDI) and MS Quality of Life-54 (MSQoL-54), respectively.

RESULTS

This study showed significant group-by-time interactions on long-term verbal memory, walking capacity, cognitive fatigue, and physical quality of life in favor of the EG (p<0.003). Moreover, verbal memory, visuospatial memory, verbal fluency, information processing speed, walking capacity, fatigue, and quality of life improved in the EG (p<0.05) while only verbal memory increased in the CG (p<0.05). Furthermore, the change in visuospatial memory was associated with the change in mental quality of life (r:0.352, p: 0.041) while the change in verbal fluency (r: -0.362, p:0.035) and processing speed (r: -0.356, p:0.039) were associated with the change in mood.

CONCLUSION

Combined exercise training has beneficial effects on different cognitive functions in mild disabled RRMS patients with cognitive impairment. In addition, there is a mutual relationship in improvements in cognitive functions, mood, and quality of life after exercise.

Exercise training and cognitive performance in persons with multiple sclerosis: A systematic review and multilevel meta-analysis of clinical trials

BACKGROUND

Cognitive impairment is common, debilitating, and poorly managed in persons with multiple sclerosis (pwMS). Exercise training might have positive effects on cognitive performance in pwMS, yet the overall magnitude, heterogeneity, and potential moderators remain unclear.

OBJECTIVE

This three-level meta-analysis aims to identify the effects of exercise training and those of exercise modalities on global and domain-specific cognitive performance in pwMS.

METHODS

MEDLINE, PsycInfo, SportDiscus, CENTRAL, and EMBASE were screened for randomized and non-randomized clinical trials from inception to 27 January 2020, yielding 3091 articles. Based on titles and abstracts, 75 articles remained in the selection process. After full-text evaluation, 13 studies were finally selected (PROSPERO pre-registered).

RESULTS

The pooled effect of exercise training on the global cognitive performance was null (g = 0.04, 95% confidence interval (CI): -0.11 to 0.18) and no significant differences were displayed among domains. Heterogeneity within studies was null (I(2)2= 0.0%) and between studies was low (I(3)2= 25.1%). None of the moderators (exercise modalities, age, Expanded Disability Status Scale (EDSS), supervision, cognitive domains) reached significance. However, the exercise volume explained most of the overall heterogeneity (slope = 4.651 × 10^-5, R(2)2 = 100%, R(3)2 = 52.34%).

CONCLUSION

These results do not support the efficacy of exercise training on global or domain-specific cognitive performance in pwMS. Future studies are needed to determine whether higher training dose are beneficial.

Treatment and management of cognitive dysfunction in patients with multiple sclerosis

Cognitive impairment is a common and devastating manifestation of multiple sclerosis (MS). Although disease-modifying therapies have been efficacious for reducing relapse rates in MS, such treatments are ineffective for treating cognitive dysfunction. Alternative treatment approaches for mitigating cognitive problems are greatly needed in this population. To date, cognitive rehabilitation and exercise training have been identified as possible candidates for treating MS-related cognitive impairment; however, cognitive dysfunction is still often considered to be poorly managed in patients with MS. This Review provides a comprehensive overview of recent developments in the treatment and management of cognitive impairment in people with MS. We describe the theoretical rationales, current states of the science, field-wide challenges and recent advances in cognitive rehabilitation and exercise training for treating MS-related cognitive impairment. We also discuss future directions for research into the treatment of cognitive impairment in MS that should set the stage for the inclusion of cognitive rehabilitation and exercise training into clinical practice within the next decade.

Feasibility study of a 10-week community-based program using the WalkWithMe application on physical activity, walking, fatigue and cognition in persons with Multiple Sclerosis

BACKGROUND

People with Multiple Sclerosis (pwMS) show diverse symptoms, such as fatigue and decline in motor and cognitive function. Physical activity shows to have a positive impact on many of these symptoms. However, many pwMS lead sedentary lives. Objectives of this study were to evaluate the feasibility of prolonged use of the WalkWithMe, a personalized mobile application that supports pwMS in walking at home, and its effect on physical activity, walking, fatigue and cognition in persons with MS.

METHODS

Nineteen pwMS were enrolled in a 10-week home-based intervention with the WalkWithMe application after setting personal goals based on baseline testing values, where twelve patients completed the program. Before and after the intervention, motor (6MWT, T25FW, 5-STS, NHPT) and cognitive function (PASAT and SDMT) were evaluated, together with the patient reported impact on walking, physical activity, quality of life and fatigue by MSWS-12, IPAQ, SF-36, MSIS-29, MFIS and FSS, respectively.

RESULTS

Significant improvement was seen for some parts of self-reported physical activity and quality of life (IPAQ: walking, p = 0.04, leisure, p = 0.02; SF-36: physical functioning, p = 0.02), cognition (SDMT, p = 0.01), cognitive fatigability (PASAT, p = 0.05), lower limb strength (5-STS, p = 0.05) and dominant hand function (NHPT, p = 0.002).

CONCLUSION

This feasibility study was successful at improving categories of self-reported physical activity, lower limb functional strength, hand function and cognition, but results need to be interpreted with caution, given the small and not always clinically relevant changes. Larger sample sizes in a controlled experimental design are needed to confirm these results.

Protocol for a systematically-developed, phase I/II, single-blind randomized controlled trial of treadmill walking exercise training effects on cognition and brain function in persons with multiple sclerosis

Slowed cognitive processing speed (CPS) is a common and debilitating consequence of multiple sclerosis (MS) that is notoriously difficult to treat. As such, we undertook a systematic line of research that indicated that supervised, progressive treadmill walking exercise (TMWX) training might improve CPS and brain functioning among fully-ambulatory persons with MS. The current study will be the first adequately-powered, single-blind randomized controlled trial (RCT) that examines the efficacy of 12-weeks of TMWX training compared with an active control condition on CPS, thalamocortical brain connectivity (based on resting-state fMRI), and exploratory functional outcomes in 88 fully-ambulatory persons with MS who present with slowed CPS. The intervention condition involves supervised, progressive TMWX training 3 times/week over 12-weeks; this initially involves 15-min of light-to-moderate intensity TMWX that progresses up to 40-min of vigorous intensity TMWX. The active control condition involves supervised, minimal intensity, stretching-and-resistance exercise that will be delivered on the same frequency as the intervention condition. The primary study outcomes involve Symbol Digit Modalities Test performance (i.e., CPS) and fMRI-based measures of thalamocortical resting-state functional connectivity. Exploratory study outcomes involve measures of community participation, activities of daily living, quality of life, and functional mobility. All study outcomes will be administered before and after the 12-week study period by treatment-blinded assessors. If successful, the current study will provide the first Class I evidence for the effects of TMWX training as an approach for improving CPS and its neural correlate, and possibly mitigating the impact of slowed CPS on functional outcomes in MS.

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.

Will behavioral treatments for cognitive impairment in multiple sclerosis become standards-of-care?

Cognitive impairment is common and debilitating in persons with multiple sclerosis (MS), and further is poorly-managed by pharmacotherapy. Cognitive rehabilitation and exercise training have been identified as promising behavioral approaches for managing MS-related cognitive impairment based on systematic reviews and meta-analyses. However, each body of literature is associated with similar sets of methodological shortcomings, as has been identified by periodic systematic reviews and meta-analyses. Thus, there is little generalizability or transportability research supporting either behavioral approach for managing cognitive dysfunction in this population under real-world conditions (i.e., as a standard-of-care). To that end, this paper aims to catalyze the advancement of cognitive rehabilitation and exercise training research in MS, respectively, towards the successful implementation of generalizability/transportability trials. This first involves critical examinations of the respective cognitive rehabilitation and exercise training literatures in MS from a chronological perspective, with particular emphasis on how the fields have each evolved in response to systematic reviews and meta-analyses. Accordingly, the current paper then provides a roadmap for harmonizing research in those areas to systematically and efficiently inform the development of generalizability/transportability trials for behavioral approaches to manage MS-related cognitive dysfunction. This involves the recognition of overlapping facilitators and impediments for progress in each field, including considerations for the implementation of neuroimaging. Ultimately, the provision of such a framework aims to shorten the timeline for research to influence clinical practice and improve the lives of cognitively-impaired persons with MS.

Response heterogeneity in fitness, mobility and cognition with exercise-training in MS

BACKGROUND

Exercise-training is a beneficial approach for improving function in persons with multiple sclerosis (MS). However, it is unlikely that every participant who engages in an exercise-training intervention will demonstrate similar benefits. Identifying factors that may influence the accrual of specific exercise-training benefits can aid in the development of optimized rehabilitation interventions for improving specific outcomes in MS.

OBJECTIVE

This study described possible response heterogeneity in physical fitness, mobility and cognitive outcomes with exercise-training and identified baseline performance, compliance and demographic/clinical outcomes as possible predictors of exercise-related changes in those outcomes.

METHODS

Thirty-two persons with MS-related mobility disability completed 6-months of multimodal exercise-training. Physical fitness, mobility and cognitive processing speed (CPS) were measured before and after the 6 months.

RESULTS

There was response heterogeneity in fitness, mobility and cognitive outcomes with multimodal exercise-training. Low baseline aerobic fitness, slow walking speed and slow CPS were associated with greater exercise-related improvements in those respective outcomes.

CONCLUSIONS

Those with MS-related mobility disability who have the lowest aerobic fitness, walking speed and CPS might benefit the most from multimodal exercise-training. This provides critical evidence for informing the development of a precision medicine framework for improving targeted outcomes with exercise-training in MS.

Exploring the feasibility of a mild and short 4-week combined upper limb and breathing exercise program as a possible home base program to decrease fatigue and improve quality of life in ambulatory and non-ambulatory multiple sclerosis individuals

PURPOSE

To evaluate the feasibility of a combined upper limb and breathing exercise for a home-based program and to explore its effect on primary fatigue and quality of life in ambulatory and non-ambulatory individuals with multiple sclerosis (MS) in a short time.

METHOD

Nineteen individuals with MS were assigned into semi-controlled pre-post feasibility study based on Expanded Disability Status Scale (EDSS) status and divided into two groups: exercise (five ambulatory, five non-ambulatory; EDSS 1.0-8.0) and related control with no exercise (four ambulatory, five non-ambulatory; EDSS 1.0-7.5). Exercise group performed combined upper limb and breathing exercise in a controlled group (2 days/week, 60 min/session) accompanied by independent home exercise (3 days/week, ≥ 20 min/session). Participants underwent measures of fatigue impact (Modified Fatigue Impact Scale (MFIS) and quality of life (RAND Medical outcomes study 36-item short-form health survey (SF-36)) before and after a 4-week period.

RESULTS

The MFIS (physical, psychosocial, total) showed statistically significant group-by-time interaction in ambulatory (p = 0.033, d = 1.60; p = 0.039, d = 1.59; p = 0.033, d = 1.62) and non-ambulatory individuals (p = 0.009, d = 2.42; p = 0.018, d = 1.96; p = 0.0008, d = 3.92). Physical functioning (SF-36) showed statistically significant group-by-time interaction in ambulatory (p = 0.014, d = 2.14) but no significance in non-ambulatory (p = 0.368, d = 0.68) individuals. Despite the absent statistical significance, there were large intervention effects on MFIS cognitive scores for ambulatory (d = 1.28) and non-ambulatory (d = 1.47), and on other SF-36 scores for ambulatory (general health: d = 1.76 and pain: d = 1.02) and non-ambulatory (physical limitation: d = 1.03 and emotional well-being: d = 0.94) individuals.

CONCLUSION

Our 4-week program reduced some aspects of fatigue and improved some aspects of quality of life in a small group of ambulatory and non-ambulatory individuals with MS. Good feasibility and significant positive changes from baseline warrant further exploratory work.

TRIAL REGISTRATION

Name of the registry: The Impact of Exercise Training on Living Quality in Multiple Sclerosis. Registration: The study was registered at www.clinicaltrial.gov on July 14, 2017. First participant enrollment: August 28, 2017. URL: 602-01/17-01-147; Trial registration ID: NTC03222596.

Response Heterogeneity With Exercise Training and Physical Activity Interventions Among Persons With Multiple Sclerosis

Multiple sclerosis (MS) is a heterogeneous disease, both in its pathology and symptomology. This poses a challenge for the medical management and rehabilitation of MS; however, physical activity and exercise training are rehabilitation approaches that have demonstrated beneficial effects on many of the burdensome consequences of MS such as mobility impairment and fatigue. Given the heterogeneous course of MS, it is possible that outcomes of physical activity and exercise training interventions demonstrate heterogeneity both in the magnitude and pattern of change, but there has been little focus on response heterogeneity with these interventions among persons with MS. In this narrative review, a search of the existing literature was performed to identify studies that reported individual participant data, which was used to describe the variability in the response to physical activity and exercise training interventions among persons with MS. Inter-individual variability seemingly occurs across outcomes and modalities, which underscores the consideration of factors that might influence response heterogeneity. Factors related to MS disease characteristics, nervous system damage, and the degree of MS-related disability might influence individual responsiveness. Large-scale studies that permit the examination of heterogeneity and its predictors will inform future research on the area of physical activity and exercise training in MS, and lead to the development of individually tailored rehabilitation approaches that will more effectively elicit change.

Rationale and design of a single-blind, randomised controlled trial of exercise training for managing learning and memory impairment in persons with multiple sclerosis

INTRODUCTION

This randomised controlled trial (RCT) examines treadmill walking exercise training effects on learning and memory performance, hippocampal volume, and hippocampal resting-state functional connectivity in persons with multiple sclerosis (MS) who have objective impairments in learning new information.

METHODS AND ANALYSIS

Forty fully ambulatory persons with MS who demonstrate objective learning and memory impairments will be randomly assigned into either the intervention or active control study conditions. The intervention condition involves supervised, progressive treadmill walking exercise training three times per week for a 3-month period. The active control condition involves supervised, progressive low-intensity resistive exercise that will be delivered at the same frequency as the intervention condition. The primary outcome will involve composite performance on neuropsychological learning and memory tests, and the secondary outcomes involve MRI measures of hippocampal volume and resting-state functional connectivity administered before and after the 3-month study period. Outcomes will be administered by treatment-blinded assessors using alternate test forms to minimise practice effects, and MRI data processing will be performed by blinded data analysts.

ETHICS AND DISSEMINATION

This study has been approved by a university institutional review board. The primary results will be disseminated via peer-reviewed publications and the final data will be made available to third parties in applicable data repositories. If successful, the results from this study will eventually inform subsequent RCTs for developing physical rehabilitation interventions (ie, treadmill walking exercise training) for improving learning and memory and its relationship with hippocampal outcomes in larger samples of cognitively impaired persons with MS. The results from this early-phase RCT will further lay preliminary groundwork for ultimately providing clinicians and patients with guidelines for better using chronic treadmill walking exercise for improving cognition and brain health. This approach is paramount as learning and memory impairment is common, burdensome and poorly managed in MS.

TRIAL REGISTRATION NUMBER

NCT03319771; Pre-results.

Cognitive Deficits in Multiple Sclerosis: Recent Advances in Treatment and Neurorehabilitation

PURPOSE OF REVIEW

This article highlights recent progress in research on treatment and neurorehabilitation of cognitive impairment in multiple sclerosis (MS) including pharmacological interventions, physical exercise, and neuropsychological rehabilitation, both in conventional and technology-assisted settings.

RECENT FINDINGS

The most consistent evidence in terms of improvement or preservation of circumscribed cognitive scores in MS patients comes from moderately sampled randomized clinical trials on multimodal approaches that combine conventional or computerized neuropsychological training with psychoeducation or cognitive behavioral therapy. Disease-modifying treatments also appear to have beneficial effects in preventing or attenuating cognitive decline, whereas there is little evidence for agents such as donepezil or stimulants. Finally, physical exercise may yield some cognitive improvement in MS patients. Despite substantial and often promising research efforts, there is a lack of validated and widely accepted clinical procedures for cognitive neurorehabilitation in MS. Development of such approaches will require collaborative efforts towards the design of interventions that are fundamentally inspired by cognitive neuroscience, potentially guided by neuroimaging, and composed of conventional neuropsychological training and cognitive behavioral therapy as well as physical exercise and therapeutic video games. Subsequently, large-scale validation will be needed with meaningful outcome measures reflecting transfer to everyday cognitive function and maintenance of training effects.

Integrative CNS Plasticity With Exercise in MS: The PRIMERS (PRocessing, Integration of Multisensory Exercise-Related Stimuli) Conceptual Framework

There is a proliferation of research examining the effects of exercise on mobility and cognition in the general population and those with neurological disorders as well as focal research examining possible neural mechanisms of such effects. However, there is seemingly a lack of focus on what it is about exercise, in particular, that drives adaptive central nervous system neuroplasticity. We propose a novel conceptual framework (ie, PRIMERS) that describes such adaptations as occurring via activity-dependent neuroplasticity based on the integrative processing of multisensory input and associated complex motor output that is required for the regulation of physiological systems during exercise behavior. This conceptual framework sets the stage for the systematic examination of the effects of exercise on brain connectivity, brain structure, and molecular/cellular mechanisms that explain improvements in mobility and cognition in the general population and persons with multiple sclerosis (MS). We argue that exercise can be viewed as an integrative, systems-wide stimulus for neurorehabilitation because impaired mobility and cognition are common and co-occurring in MS.

Aerobic Capacity Is Not Associated with Most Cognitive Domains in Patients with Multiple Sclerosis-A Cross-Sectional Investigation

(1) Background: Cognitive impairment is highly prevalent in multiple sclerosis (MS). Staying physically fit may be associated with preservation of cognitive performance in persons with MS (pwMS); (2) Objective: To investigate the association between aerobic capacity and the cognitive domains of information processing, learning and memory, and verbal fluency as well as single and composite z-scores of the Brief Repeatable Battery of Neuropsychological tests (BRBNT) in pwMS; (3) Methods: All subjects first performed the BRBNT and then a maximal oxygen consumption (VO₂-max) test on a bicycle ergometer as a measure of aerobic capacity. Simple and multiple (adjusting for age, sex, and education level) regression analyses were performed to evaluate the relationship between aerobic capacity and cognitive performance in different domains. Published international norms were used to compute z-scores for each individual and composite BRBNT score. Furthermore, cognitive impairment was defined as one or more z-scores ≤−1.5 standard deviation (SD) of healthy controls; (4) Results: Eighty-four subjects were included (44.9 ± 9 years, 16.3 ± 2 education years, Expanded Disability Status Scale (EDSS): 2.6 ± 1.4, MS-type (relapsing-remitting, primary progressive, or secondary progressive): 73/6/5, disease duration: 9.9 ± 7 years, VO₂-max: 28.4 ± 7.0 mL O₂/min/kg). No significant associations between aerobic capacity and cognitive performance in the individual BRBNT tests were found, except that a weak relationship was found between aerobic capacity and the composite processing speed z-score (R² = 0.06, p = 0.02). The average global BRBNT z-score (−0.2 ± 0.66) was not associated with aerobic capacity. Comparison of the cognitively impaired group (34.5%) with the nonimpaired group (65.5%) showed lower aerobic capacity in the impaired group (25.9 ± 1 vs. 29.7 ± 1 mLO₂/min/kg, p = 0.02); (5) Conclusions: Limited support was found for an association between performance in most cognitive domains and aerobic capacity in the present MS group with a third of patients showing signs of cognitive impairments.

Interplay Between Age and Neuroinflammation in Multiple Sclerosis: Effects on Motor and Cognitive Functions

Aging is one of the main risk factors for the development of many neurodegenerative diseases. Emerging evidence has acknowledged neuroinflammation as potential trigger of the functional changes occurring during normal and pathological aging. Two main determinants have been recognized to cogently contribute to neuroinflammation in the aging brain, i.e., the systemic chronic low-grade inflammation and the decline in the regulation of adaptive and innate immune systems (immunosenescence, ISC). The persistence of the inflammatory status in the brain in turn may cause synaptopathy and synaptic plasticity impairments that underlie both motor and cognitive dysfunctions. Interestingly, such inflammation-dependent synaptic dysfunctions have been recently involved in the pathophysiology of multiple sclerosis (MS). MS is an autoimmune neurodegenerative disease, typically affecting young adults that cause an early and progressive deterioration of both cognitive and motor functions. Of note, recent controlled studies have clearly shown that age at onset modifies prognosis and exerts a significant effect on presenting phenotype, suggesting that aging is a significant factor associated to the clinical course of MS. Moreover, some lines of evidence point to the different impact of age on motor disability and cognitive deficits, being the former most affected than the latter. The precise contribution of aging-related factors to MS neurological disability and the underlying molecular and cellular mechanisms are still unclear. In the present review article, we first emphasize the importance of the neuroinflammatory dependent mechanisms, such as synaptopathy and synaptic plasticity impairments, suggesting their potential exacerbation or acceleration with advancing age in the MS disease. Lastly, we provide an overview of clinical and experimental studies highlighting the different impact of age on motor disability and cognitive decline in MS, raising challenging questions on the putative age-related mechanisms involved.

Treadmill walking exercise training and brain function in multiple sclerosis: Preliminary evidence setting the stage for a network-based approach to rehabilitation

Exercise training has been identified as a highly promising approach for managing the cognitive consequences of multiple sclerosis (MS). This study represents a secondary analysis of resting-state functional connectivity (RSFC) magnetic resonance imaging data from a pilot treadmill walking exercise training intervention for improving cognitive processing speed (CPS) in MS. There were large intervention effects on RSFC between the thalamus and right superior frontal gyrus (d = 1.92) and left medial frontal gyrus (d = 1.70). There further were moderate-to-large intervention effects on CPS (d = 0.72). Such preliminary data highlight FC within thalamocortical circuitry as a potential target for rehabilitation interventions for improving CPS in cognitively impaired individuals with MS.

Exercise as a Countermeasure to Declining Central Nervous System Function in Multiple Sclerosis

PURPOSE

The decline of central nervous system (CNS) function is a hallmark characteristic of multiple sclerosis (MS) that can manifest as cognitive impairment. We believe that exercise represents a potential behavioral approach for counteracting the declines in CNS structure and associated function among persons with MS (ie, exercise as a countermeasure of CNS decline). This theory is important because disease-modifying drugs represent a first-line approach for modifying the immune system and its effects on the CNS, but these drugs do not generally demonstrate robust improvements in cognitive performance.

METHODS

To the best of our knowledge, this article presents the first argument positioning exercise as a countermeasure for CNS decline in MS.

FINDING

The reviewed research indicates a proliferating body of evidence describing physical fitness, physical activity, and exercise effects on cognitive performance and neuroimaging outcomes (ie, CNS functioning) in MS, with the consistent and strong association between cognitive performance and neuroimaging outcomes in this population as a backdrop.

IMPLICATIONS

We further present a framework and future research directions for better positioning exercise as a possible neuroprotective behavior against declining CNS function in MS.

Exercise therapy in multiple sclerosis and its effects on function and the brain

Exercise therapy is a promising nonpharmacological therapy in people with multiple sclerosis (MS). Although exercise training may induce a transient worsening of symptoms in some MS patients, it is generally considered safe and does not increase the risk of relapses. Exercise training can lead to clinically relevant improvements in physical function, but should be considered an adjunct to specific task-based training. Exercise has also shown positive effects on the brain, including improvements in brain volume and cognition. In summary, exercise therapy is a safe and potent nonpharmacological intervention in MS, with beneficial effects on both functional capacity and the brain.