Pilot study: evaluation of the effect of functional electrical stimulation cycling on muscle metabolism in nonambulatory people with multiple sclerosis

Mechanomyography reflects the changes in oxygenated hemoglobin during electrically evoked cycling in individuals with spinal cord injury

BACKGROUND

Functional electrical stimulation (FES) cycling has been reported to enhance muscle strength and improve muscle fatigue resistance after spinal cord injury (SCI). Despite its proposed benefits, the quantification of muscle fatigue during FES cycling remains poorly documented. This study sought to quantify the relationship between the vibrational performance of electrically-evoked muscles measured through mechanomyography (MMG) and its oxidative metabolism through near-infrared spectroscopy (NIRS) characteristics during FES cycling in fatiguing paralyzed muscles in individuals with SCI.

METHODS

Six individuals with SCI participated in the study. They performed 30 min of FES cycling with MMG and NIRS sensors on their quadriceps throughout the cycling, and the signals were analyzed.

RESULTS

A moderate negative correlation was found between MMG root mean square (RMS) and oxyhaemoglobin (O2Hb) [r = -0.38, p = 0.003], and between MMG RMS and total hemoglobin (tHb) saturation [r = -0.31, p = 0.017]. Statistically significant differences in MMG RMS, O2Hb, and tHb saturation occurred during pre- and post-fatigue of FES cycling (p < 0.05).

CONCLUSIONS

MMG RMS was negatively associated with O2Hb and muscle oxygen derived from NIRS. MMG and NIRS sensors showed good inter-correlations, suggesting a promising use of MMG for characterizing metabolic fatigue at the muscle oxygenation level during FES cycling in individuals with SCI.

The effects of hybrid functional electrical stimulation interval training on aerobic fitness and fatigue in people with advanced multiple sclerosis: An exploratory pilot training study

BACKGROUND

Improving aerobic fitness in people with advanced multiple sclerosis (MS) may reduce fatigue, and lower the risk of cardiovascular disease, as has been found for people with mild to moderate MS. Training targeting aerobic fitness can be challenging due to paresis, access to suitable equipment and fatigue. The aim of this study was to investigate whether people with advanced multiple sclerosis could perform functional electrical stimulation (FES) cycling combined with arm crank interval exercise (hybrid FES interval training) training, and its effects on aerobic fitness and fatigue.

METHODS

Hybrid FES interval training was performed 2 d/wk for 12 weeks. Each session consisted of 40 min of continuous FES cycling with arm crank intervals of 30 s work/30 s rest added concurrently for 20 min. The intensity target was a minimum of 60 % of arm crank power and 'hard' measured by rate of perceived exertion (RPE). Attendance, compliance to intensity and time targets, adverse events, and drop outs were measured. Aerobic fitness was assessed by an arm crank maximal test. Fatigue was measured via the Modified Fatigue Impact Scale (MFIS).

RESULTS

Seven participants (6 female; age 57.1 ± 7.8y; Expanded Disability Status Scale 7.1 ± 0.8) with advanced MS attended 80 ± 10.4 % of the scheduled exercise sessions and there were no adverse events or drop outs. Average RPE at the end of each training session was 15.1 ± 2.1, representing vigorous intensity exercise. Aerobic fitness did not change pre- to post-intervention (14.2 ± 5.7 to 14.8 ± 6.0 mL/kg/min [p = 0.43]), and resulted in a small effect size (ES) (0.30). The reduction in fatigue during the intervention (31.0 ± 10.4 to 21.7 ± 11.4 [p = 0.10]), resulted in a moderate to large ES (-0.77).

CONCLUSION

Hybrid FES interval training could be performed 2 days per week for 12 weeks and represented vigorous intensity exercise, but there was no change in aerobic fitness. The reduction in participants' perceptions of fatigue represented a moderate to large ES, indicating hybrid FES interval training might be suitable for people with advanced MS who need exercise equipment appropriate for their condition.

CLINICAL TRIAL REGISTRATION

This study was registered with Australian and New Zealand Clinical Trials Register (U1111-1194-2040).

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.

Exercise and Sports Science Australia (ESSA) position statement on exercise for people with mild to moderate multiple sclerosis

OBJECTIVES

Multiple sclerosis (MS), the most common chronic and progressive neurological condition of the central nervous system, affects 26,000 Australian adults. Exercise training has beneficial effects on MS-related impairments including reduced muscular strength, poor aerobic capacity and impaired mobility, and in consequence can improve quality of life. This Position Statement provides evidence-based recommendations for exercise prescription and delivery of exercise training for people with MS with mild to moderate disability.

DESIGN AND METHODS

Synthesis of published works within the field of exercise training in MS.

RESULTS

Exercise provides many benefits to people with MS. There is strong evidence that resistance and aerobic training, performed 2 to 3 times per week at a moderate intensity, are safe and can improve muscle strength, cardiorespiratory fitness, balance, fatigue, functional capacity, mobility and quality of life in people with MS with mild to moderate disability (Expanded Disease Severity Scale (EDSS) ≤ 6.5). However, the evidence for those with severe disability (EDSS >6.5) is less clear. The effects of exercise on MS pathogenesis, central nervous structures and other outcomes such as depression and cognitive impairment, have not been adequately investigated. Effective exercise interventions to improve balance, joint contractures and reduce falls in people with MS are also urgently needed as well as investigations of long-term (≥1 year) effects of exercise training.

CONCLUSIONS

Resistance and aerobic training exercises are effective to alleviate some characteristic signs and symptoms in MS and should be supplemented by balance exercise to prevent falls. Exercise training programs should be prescribed and delivered by qualified exercise professionals. It is important to recognise and accommodate exercise-associated complications such as fatigue and heat sensitivity.

Brain and Muscle: How Central Nervous System Disorders Can Modify the Skeletal Muscle

It is widely known that nervous and muscular systems work together and that they are strictly dependent in their structure and functions. Consequently, muscles undergo macro and microscopic changes with subsequent alterations after a central nervous system (CNS) disease. Despite this, only a few researchers have addressed the problem of skeletal muscle abnormalities following CNS diseases. The purpose of this review is to summarize the current knowledge on the potential mechanisms responsible for changes in skeletal muscle of patients suffering from some of the most common CSN disorders (Stroke, Multiple Sclerosis, Parkinson’s disease). With this purpose, we analyzed the studies published in the last decade. The published studies show an extreme heterogeneity of the assessment modality and examined population. Furthermore, it is evident that thanks to different evaluation methodologies, it is now possible to implement knowledge on muscle morphology, for a long time limited by the requirement of muscle biopsies. This could be the first step to amplify studies aimed to analyze muscle characteristics in CNS disease and developing rehabilitation protocols to prevent and treat the muscle, often neglected in CNS disease.

Effects of Functional Electrical Stimulation Cycling on Fatigue and Quality of Life in People with Multiple Sclerosis Who Are Nonambulatory

BACKGROUND

Functional electrical stimulation (FES) cycling provides an exercise opportunity for people with multiple sclerosis (MS) who are nonambulatory. This study evaluated the efficacy of FES cycling for reducing fatigue and improving quality of life in people with MS who are nonambulatory and compared outcomes with those in a control group that did not take part in FES cycling.

METHODS

Adults with MS with self-reported Expanded Disability Status Scale scores of 7.0 to 8.5 were randomized into a training group (n = 12) or a control group (n = 9). The training group performed FES cycling for 30 minutes, two to three times a week for 12 weeks. The primary outcome was safety, measured as the number and type of adverse events and any increase in symptoms. Other outcomes collected before and after the intervention were scores on the modified Ashworth Scale, manual muscle test, 5-item Modified Fatigue Impact Scale (MFIS-5), Fatigue Scale for Motor and Cognitive Functions (FSMC), Medical Outcomes Study Pain Effects Scale, Patient Health Questionnaire-9 (PHQ-9), Multiple Sclerosis Quality of Life-54 (MSQOL-54), and Exercise Self-Efficacy Scale.

RESULTS

Twelve participants completed the study and were analyzed. Six participants completed training with no adverse events. The MFIS-5 (Cohen's d = 0.60), FSMC (Cohen's d = 0.37), and PHQ-9 (Cohen's d = 0.67) scores and the physical health composite of the MSQOL-54 (Cohen's d = 1.48) improved for the training group compared with the control group (n = 6).

CONCLUSIONS

Functional electrical stimulation cycling is safe for people with MS who are nonambulatory and may reduce fatigue and improve measurements of quality of life.

Safety and Feasibility of Various Functional Electrical Stimulation Cycling Protocols in Individuals With Multiple Sclerosis Who Are Nonambulatory

Objective

To examine the safety, feasibility, and response to functional electrical stimulation (FES) cycling protocols requiring differing levels of effort in people with multiple sclerosis (MS) who are nonambulatory.

Design

Pilot study with pre-post intervention testing.

Setting

Outpatient clinic setting of a long-term acute care hospital.

Participants

Individuals (N=10) with MS (6 men; mean age 58.6±9.86y) who use a wheelchair for community mobility. Participants’ Expanded Disability Status Scale score ranged from 6.5 to 8.5 (median 7.5).

Intervention

Participants performed 3 or 4 FES cycling protocols requiring different levels of volitional effort during 6-8 testing sessions.

Main Outcome Measures

The primary outcome was safety, measured by adverse events and increase in MS symptoms, all assessed throughout, immediately post- and 1 day postsession. FES cycling performance for each protocol was also recorded. Exploratory outcome measures collected before and after all testing sessions included functional assessment of MS, MS Impact Scale, Exercise Self Efficacy Scale, Patient Health Questionnaire-9 item, and the Zarit Caregiver Burden Scale.

Results

All participants (4 women, 6 men) completed all testing sessions. There were no serious adverse events or differences in vitals or symptoms between protocols. Two participants had an isolated episode of mild hypotension. Changes in pain, spasticity, and fatigue were minimal. Five participants were able to cycle for 30 minutes and completed interval training protocols requiring increasing difficulty. The remainder cycled for <3 minutes and completed a rest interval protocol. There was modest improvement on the exploratory outcome measures.

Conclusions

People with MS who use a wheelchair for community mobility can safely perform FES cycling requiring more effort than previously reported research. Therefore, the individuals may experience greater benefits than previously reported. Further study is required to better understand the potential benefits for optimizing function and improving health in people with MS.

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People with multiple sclerosis who are nonambulatory can safely perform functional electrical stimulation (FES) cycling using parameters requiring more effort.

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FES cycling may offer an opportunity for increased exercise stimulus or neuromuscular training if individuals are adequately challenged using an appropriate cycling protocol.

Accessible exercise equipment and individuals with multiple sclerosis: Aerobic demands and preferences

BACKGROUND

Although exercise training has benefits for individuals with multiple sclerosis (MS), research regarding the type of exercise equipment that requires the greatest aerobic demand, and consumer-based preferences, is lacking.

OBJECTIVE

To determine the aerobic demands of various pieces of accessible exercise equipment and consumer-based preferences on several domains.

METHODS

Ten individuals with moderate-severity MS had their VO2 measured during 10 minutes of moderate-intensity arm ergometry (AE), body-weight support treadmill training (BWSTT), recumbent arm-leg exercise (NuStep), FES-arm exercise (RT300), FES-leg exercise (RT300) and FES arm-leg exercise (RT200). VO2peak test was also measured on the NuStep and the RT200. Equipment preferences were determined by questionnaire after moderate exercise sessions.

RESULTS

AE required a lower VO2 compared to the NuStep (p = 0.02), and FES-arm exercise required a lower VO2 compared to the NuStep (p = 0.01) and FES arm-leg exercise (p = 0.04). There was no difference in VO2peak when using the NuStep or FES arm-leg exercise. AE was perceived as safer than BWSTT, but otherwise there were no preferences for any equipment.

CONCLUSIONS

For individuals with moderate-severity MS, arm-only exercise requires less aerobic demands than combined arm-leg exercise at a moderate intensity. Perceived risks may be greater when exercise requires a transfer, upright positioning, or assistance.

Functional Electrical Stimulation Cycling Exercise for People with Multiple Sclerosis

PURPOSE OF REVIEW

There has been substantial interest in the role of exercise for managing impairments, limitations, and disability progression among persons with multiple sclerosis (MS). Despite established benefits of exercise training for persons who have mild-to-moderate MS, the ability to deliver exercise to persons who experience higher disability remains challenging. One promising approach for exercise in this population is functional electrical stimulation (FES) cycling. This review provides a summary of the current evidence for FES cycling as an exercise training modality in persons with MS with respect to prescription, safety, tolerability, and acute and chronic effects.

RECENT FINDINGS

We searched the literature for studies involving FES cycling exercise in persons with MS published in English up until July 2019. Eight studies were retrieved: two studies examined acute effects, two studies examined chronic effects, and four studies reported on both acute and chronic effects of FES cycling exercise. The overall quality of the studies was low, with only one, small, randomized controlled trial (RCT). There is limited but promising evidence for the application of FES cycling exercise among persons with MS who have moderate-to-severe disability. Participants were capable of engaging in regular FES cycling exercise (~ 30 min, 2-3×/week), with few, mild adverse events experienced. Preliminary evidence from small, mostly uncontrolled trials supports the potential benefits of FES cycling on physiological fitness, walking mobility, and symptoms of fatigue and pain. High-quality RCTs of FES cycling exercise are necessary for providing recommendations for integrating exercise training in the management of advanced MS.

Evaluating functional electrical stimulation (FES) cycling on cardiovascular, musculoskeletal and functional outcomes in adults with multiple sclerosis and mobility impairment: A systematic review

BACKGROUND

People with Multiple Sclerosis (PwMS) are at an increased risk of diseases associated with low levels of physical activity (PA). Deconditioning may lead to an acceleration in the development of secondary complications from MS, impairing physical function and exacerbating disease progression. Functional Electrical Stimulation (FES) Cycling may provide a suitable lower limb exercise intervention for PwMS with mobility impairment. The effects of FES cycling on cardiovascular, musculoskeletal and functional outcomes for PwMS with mobility impairment are yet to be investigated to date.

OBJECTIVE

The objective of this review was to systematically examine the outcomes of PwMS with mobility impairment following FES cycling intervention.

METHODS

A systematic search of four electronic databases (MEDLINE, Web of Science, CINAHL and PEDro) from their inception to 8th January 2019 was performed. Inclusion criteria was (1) include human participants with definite diagnosis of MS (2) participants had to be aged 18 years or older (3) include participants with mobility impairment (determined as an average participant EDSS ≥ 6.0) (4) evaluate FES cycling as an intervention study.

RESULTS

Initial searches found 1163 studies. 9 of which met the full inclusion criteria: 5 pre-post studies with no control group, 2 randomised controlled trials (RCTs), 1 retrospective study and 1 case study. Two studies had the same participant group and intervention but reported different outcomes. Outcome data was available for n = =76 unique participants, with n = =82 completing a FES cycling intervention. Of the n = =4 papers with clear dropout rates, pooled dropout rate was 25.81%. Two papers reported non-significant improvements in aerobic capacity following a FES cycling intervention. Four papers reported no change in lower limb strength and two papers reported significant reductions in spasticity post training. Four studies failed to provide information regarding adverse events with the other studies reporting n = =10 adverse events across 36 participants.

CONCLUSION

Findings suggest FES cycle training may reduce CVD risk alongside trends for a reduction in spasticity post training, however the low quality of the literature precludes any definitive conclusions. FES cycle training appears to be well tolerated in PwMS with mobility impairment, with no serious adverse events.

Effects of Treadmill Training on Muscle Oxidative Capacity and Endurance in People with Multiple Sclerosis with Significant Walking Limitations

Background

Exercise can improve muscle function and mobility in people with multiple sclerosis (MS). However, the effects of exercise training on skeletal muscle oxidative capacity and endurance in people with MS remain unclear, and few studies have evaluated muscle plasticity in people with MS who have moderate-to-severe disability. The present study evaluated the effects of treadmill training on muscle oxidative capacity and muscle endurance and examined the relationship to walking function in people with MS who have moderate-to-severe disability.

Methods

Six adults (mean ± SD age, 50 ± 4.9 years) with MS (Expanded Disability Status Scale score, 6.0-6.5) performed treadmill training for 24 minutes approximately twice per week for approximately 8 weeks (16 sessions total) using an antigravity treadmill system. The following measures were taken before and after the intervention phase: muscle oxidative capacity in the medial gastrocnemius using near-infrared spectroscopy after 15 to 20 seconds of electrical stimulation; muscle endurance in the medial gastrocnemius using accelerometer-based mechanomyography during 9 minutes of twitch electrical stimulation in three stages (3 minutes per stage) of increasing frequency (2, 4, and 6 Hz); and walking function using the 2-Minute Walk Test.

Results

Mean ± SD muscle oxidative capacity increased from 0.64 ± 0.19 min^-1 to 1.08 ± 0.52 min^-1 (68.2%). Mean ± SD muscle endurance increased from 80.9% ± 15.2% to 91.5% ± 4.8% at 2 Hz, from 56.3% ± 20.1% to 76.6% ± 15.8% at 4 Hz, and from 29.2% ± 13.1% to 53.9% ± 19.4% at 6 Hz of stimulation in the gastrocnemius. There were no significant improvements in walking function.

Conclusions

Treadmill training can improve muscle oxidative capacity and endurance in people with MS who have moderate-to-severe levels of disability.

Case Report: Effect of Antigravity Treadmill Training on Muscle Oxidative Capacity, Muscle Endurance, and Walking Function in a Person with Multiple Sclerosis

Background

Exercise training can improve skeletal muscle metabolism in persons with multiple sclerosis (MS). However, quantification of exercise-mediated improvements in muscle metabolism has been limited, particularly in people with high levels of disability. We evaluated the effect of 9 weeks of antigravity treadmill training on muscle oxidative capacity and muscle endurance and assessed the relationship to walking function in a person with MS.

Methods

One person with MS (Expanded Disability Status Scale score, 6.5) performed treadmill training for 24 minutes approximately twice weekly for 9 weeks (16 sessions) using an antigravity treadmill system. Before and after the intervention phase, we measured muscle oxidative capacity in the medial gastrocnemius using near-infrared spectroscopy after 15 to 20 seconds of electrical stimulation; muscle endurance in the medial gastrocnemius using accelerometer-based mechanomyography during 9 minutes of twitch electrical stimulation in three stages (3 minutes per stage) of increasing frequency (2, 4, and 6 Hz); muscle strength (plantarflexion) using a maximal voluntary contraction; and walking function using the Timed 25-Foot Walk test and the 2-Minute Walk Test.

Results

Muscle oxidative capacity increased from 0.73 min^-1 to 1.08 min^-1 (48%). Muscle endurance increased from 75.9% to 84.0% at 2 Hz, from 67.8% to 76.2% at 4 Hz, and from 13.5% to 44.7% at 6 Hz. Maximal voluntary contraction decreased by 0.68 kg (15%), Timed 25-Foot Walk test speed decreased by 0.19 ft/s (20%), and 2-Minute Walk Test distance increased by 65 m (212%).

Conclusions

Muscle oxidative capacity and muscle endurance, as well as walking function, improved in a person with MS after training on an antigravity treadmill.

The Vienna FES Interview Protocol - A mixed-methods protocol to elucidate the opinions of various individuals responsible for the provision of FES exercise

Functional Electrical Stimulation (FES) is the production of electrically elicited muscle contractions to perform a function or task. It has been used as a method to regain lost body functions or support weak body functions, and as such, has been clinically available since the early seventies. Some methods are applied routinely while others have not been translated to the bedside, or are still largely restricted to laboratory use. Progress in this field might be achieved by a strong cooperation of patients, clinicians, therapists and engineers. A better insight into multiple perspectives may help in understanding the shortcomings of current FES technology. This will help direct future research efforts into design of systems and potential application in relevant populations. In addition, these findings can assist with the translation of FES technology into a community context. We outline an interview protocol designed for use at the 12th Vienna International Workshop on Functional Electrical Stimulation where the mentioned experts from the field of FES met.

Cardiorespiratory demand of acute voluntary cycling with functional electrical stimulation in individuals with multiple sclerosis with severe mobility impairment

Exercise training is one strategy for improving cardiorespiratory fitness (CRF) in multiple sclerosis (MS); however, few modalities are accessible for those with severe mobility impairment. Functional electrical stimulation (FES) cycling is an adapted exercise modality with the potential for improving CRF in people with severe MS. The objective of this study was to characterize the cardiorespiratory response of acute voluntary cycling with FES in people with MS with severe mobility impairment, and to compare this response to passive leg cycling. Eleven participants with MS that required assistance for ambulation completed a single bout of voluntary cycling with FES or passive leg cycling. Oxygen consumption, heart rate (HR), work rate (WR), and ratings of perceived exertion (RPE) were recorded throughout the session. For the FES group, mean exercising oxygen consumption was 8.7 ± 1.8 mL/(kg·min)^-1, or 63.5% of peak oxygen consumption. Mean HR was 102 ± 9.7 bpm, approximately 76.4% of peak HR. Mean WR was 27.0 ± 9.2 W, or 57.3% of peak WR, and median RPE was 13.5 (interquartile range = 5.5). Active cycling with FES was significantly (p < 0.05) more intense than passive leg cycling based on oxygen consumption, HR, WR, and RPE during exercise. In conclusion, voluntary cycling with FES elicited an acute response that corresponded with moderate-to vigorous-intensity activity, suggesting that active cycling with FES can elicit a sufficient stimulus for improving CRF.

The effect of exercise training in adults with multiple sclerosis with severe mobility disability: A systematic review and future research directions

INTRODUCTION

There is evidence for the benefits of exercise training in persons with multiple sclerosis (MS). However, these benefits have primarily been established in individuals with mild-to-moderate disability (i.e., Expanded Disability Status Scale [EDSS] scores 1.0-5.5), rather than among those with significant mobility impairment. Further, the approaches to exercise training that have been effective in persons with mild-to-moderate MS disability may not be physically accessible for individuals with mobility limitations. Therefore, there is a demand for an evidence-base on the benefits of physically accessible exercise training approaches for managing disability in people with MS with mobility impairment.

OBJECTIVE

To conduct a systematic review of the current literature pertaining to exercise training in individuals with multiple sclerosis (MS) with severe mobility disability.

METHODS

Four electronic databases (PubMed, EMBASE, OvidMEDLINE, and PsychINFO) were searched for relevant articles published up until October 2016. The review focused on English-language studies that examined the effect of exercise training in people with MS with severe mobility disability, characterized as the need for assistance in ambulation or EDSS score ≥ 6.0. The inclusion criteria involved full-text articles that: (i) included participants with a diagnosis of MS; (ii) included primarily participants with a reported EDSS score ≥ 6.0 and/or definitively described disability consistent with this level of neurological impairment; and (iii) implemented a prospective, structured exercise intervention. Data were analyzed using a descriptive approach and summarized by exercise training modality (conventional or adapted exercise training), and by outcome (disability, physical fitness, physical function, and symptoms and participation).

RESULTS

Initially, 1164 articles were identified and after removal of duplicates, 530 articles remained. In total, 512 articles did not meet the inclusion criteria. 19 articles were included in the final review. Five studies examined conventional exercise training (aerobic and resistance training), and thirteen studies examined adapted exercise modalities including body-weight support treadmill training (BWSTT), total-body recumbent stepper training (TBRST), and electrical stimulation cycling (ESAC). Outcomes related to mobility, fatigue, and quality of life (QOL) were most frequently reported. Two of five studies examining conventional resistance exercise training reported significant improvements in physical fitness, physical function, and/or symptomatic and participatory outcomes. Nine of 13 studies examining adapted exercise training reported significant improvements in disability, physical fitness, physical function, and/or symptomatic and participatory outcomes.

CONCLUSIONS

There is limited, but promising evidence for the benefits of exercise training in persons with MS with severe mobility disability. Considering the lack of effective therapeutic strategies for managing long-term disability accumulation, exercise training could be considered as an alternative approach. Further research is necessary to optimize the prescription and efficacy of exercise training for adults with MS with severe mobility disability.

Rationale and design of a randomized controlled clinical trial of functional electrical stimulation cycling in persons with severe multiple sclerosis

BACKGROUND

This randomized controlled trial (RCT) will examine the efficacy of supervised functional electrical stimulation (FES) cycling on walking performance and physiological function among persons with multiple sclerosis (MS) with severe mobility disability.

METHODS/DESIGN

This RCT will recruit 16 persons with MS that require unilateral or bilateral assistance for ambulation (i.e., Expanded Disability Status Scale (EDSS) score = 6.0-6.5). Participants will be randomized to one of two conditions: supervised FES cycling or passive cycling. The FES cycling condition will involve mild electrical stimulation that will generate an activation pattern that results in cycling the leg ergometer. The passive cycling condition will not provide any electrical stimulation, rather the movement of the pedals will be controlled by the electrical motor. Both conditions will be delivered 3 days/week for the same duration, over 6 months. Primary outcomes will include walking performance assessed as walking speed, endurance, and agility. Secondary outcomes will include physiological function assessed as cardiorespiratory fitness, muscular strength, and balance. Assessments will take place at baseline, mid-point (3-months), and immediately following the intervention (6-months).

DISCUSSION

This study will lay the foundation for the design of a future RCT by: (1) providing effect sizes that can be included in a power analysis for optimal sample size estimation; and (2) identifying cardiorespiratory fitness, muscular strength, and balance (i.e., physiological function) as mechanisms for the beneficial effects of FES cycling on walking performance. This trial will provide important information on a novel exercise rehabilitation therapy for managing walking impairment in persons with severe MS.

Altered signaling for mitochondrial and myofibrillar biogenesis in skeletal muscles of patients with multiple sclerosis

Patients with multiple sclerosis (pwMS) experience muscle weakness and lowered muscle oxidative capacity. To explore the etiology for the development of such muscle phenotype we studied skeletal muscle adenosine monophosphate (AMP)-activated protein kinase phosphorylation (phospho-AMPKα, governing mitochondrial biogenesis) and mammalian target of rapamycin phosphorylation (phospho-mTOR, governing myofibrillar biogenesis) in pwMS. After assessment of body composition, muscle strength, exercise tolerance, and muscle fiber type, muscle phospho-AMPKα and phospho-mTOR were assessed in 14 pwMS and 10 healthy controls (part 1). Next, an endurance exercise bout was executed by 9 pwMS and 7 healthy subjects, with assessment of changes in muscle phospho-AMPKα and phospho-mTOR (part 2). Increased basal muscle phospho-AMPKα and phospho-mTOR were present in MS (P < 0.01) and independently related to MS. Correlations between muscle phospho-AMPKα or phospho-mTOR and whole-body fat mass, peak oxygen uptake, and expanded disability status scale (P < 0.05) were found. After endurance exercise muscle phospho-AMPKα and phospho-mTOR remained increased in pwMS (P < 0.01). Muscle signaling cascades for mitochondrial and myofibrillar biogenesis are altered in MS and related to the impairment and disability level. These findings indicate a link between muscle signaling cascades and the level of disability and impairment, and thus may open a new area for the development of novel therapies for peripheral muscle impairment in MS.