Accurate Prediction of Cardiorespiratory Fitness Using Cycle Ergometry in Minimally Disabled Persons With Relapsing-Remitting Multiple Sclerosis

Study protocol: exercise training for treating major depressive disorder in multiple sclerosis

BACKGROUND

Major depressive disorder (MDD) is prevalent, yet sub-optimally treated among persons with multiple sclerosis (MS). We propose that exercise training may be a promising approach for treating depression in persons with MS who have MDD. Our primary hypothesis predicts a reduction in depression severity immediately after an exercise training intervention compared with minimal change in an attention control condition, and the reduction will be maintained during a follow-up period.

METHODS

This study involves a parallel-group, assessor-blinded RCT that examines the effect of a 4-month home-based exercise training intervention on depression severity in a sample of persons with MS who have MDD based on the MINI International Neuropsychiatric Interview. The primary outcomes of depression severity are the Patient Health Questionnaire-9 and Hamilton Depression Rating Scale. Participants (N = 146) will be recruited from within 200 miles of the University of Illinois at Chicago and randomized (1:1) into either a home-based exercise training condition or control condition with concealed allocation. The exercise training and social-contact, attention control (i.e., stretching) conditions will be delivered remotely over a 4-month period and supported through eight, 1:1 Zoom-based behavioral coaching sessions guided by social-cognitive theory and conducted by persons who are uninvolved in screening, recruitment, random assignment, and outcome assessment. We will collect outcome data at 0, 4 and 8 months using treatment-blinded assessors, and data analyses will involve intent-to-treat principles.

DISCUSSION

If successful, the proposed study will provide the first Class I evidence supporting a home-based exercise training program for treating MDD in persons with MS. This is critical as exercise training would likely have positive secondary effects on symptoms, cognition, and quality of life, and provide a powerful, behavioral approach for managing the many negative outcomes of MDD in MS. The program in the proposed research is accessible and scalable for broad treatment of depression in MS, and provides the potential for integration in the clinical management of MS.

TRIAL REGISTRATION

The trial was registered on September 10, 2021 at clinicaltrials.gov with the identifier NCT05051618. The registration occurred before we initiated recruitment on June 2, 2023.

The effect of aerobic exercise alone and in combination with cognitive behavioural therapy on obsessive compulsive disorder: A randomized control study

PURPOSE

Cognitive behavioural therapy (CBT) has been found to be an effective treatment for OCD, but there remains a significant proportion of individuals who fail to show a treatment response. Aerobic exercise has previously been associated with decreases in anxiety and depression, as well as improvements in OCD symptoms in small-scale studies. The purpose of the present research was to use a randomized control trial design to examine the effects of exercise alone and in combination with CBT, on OCD symptoms and secondary symptoms.

METHOD

125 participants were randomly assigned to one of four treatment groups: waitlist control, exercise, CBT, and CBT with exercise. OCD symptom severity was measured at four points over the course of treatment, secondary outcome measures were gathered at three points over treatment.

RESULTS

CBT alone and combined with exercise was associated with significantly greater OCD symptom reduction than exercise alone or the control groups. Total exercise frequency predicted OCD symptom reduction in the groups in which exercise was measured. Group membership did not significantly predict reductions in secondary outcome measures.

CONCLUSION

Exercise frequency, rather than the presence or absence of exercise, appears to predict OCD symptom reduction, as did participation in CBT.

Protocol for an exploratory, randomised, single-blind clinical trial of aerobic exercise to promote remyelination in multiple sclerosis

INTRODUCTION

There is an urgent need for remyelinating therapies that restore function in people with multiple sclerosis (pwMS). Aerobic exercise is a promising remyelinating strategy because it promotes remyelination in animal models both independently and synergistically with medications. Here, in this study, we present an innovative, randomised, single-blind, clinical trial designed to explore: the relationship between demyelination and mobility (part 1), and if 24 weeks of aerobic exercise promotes remyelination in pwMS (part 2).

METHODS AND ANALYSIS

Sedentary participants (n=60; aged 18-64 years) with stable MS will undergo a baseline visit with the following outcomes to assess associations between demyelination and mobility (part 1): spinal cord demyelination (somatosensory-evoked potentials, SSEPs), mobility (6-Minute Timed Walk, Timed 25-Foot Walk, Timed Up and Go, 9-Hole Peg Test) and patient-reported outcomes (PROs). After baseline testing, participants with significantly prolonged SSEP latency will advance to the clinical exercise trial (part 2) and will be randomised 1:1 to active or control conditions for 24 weeks. The active condition will be aerobic stationary cycling three times per week with graded virtual supervision. The control condition will be monthly virtual MS symptom education groups (six sessions). SSEP latency (remyelination endpoint), mobility outcomes and PROs will be measured at 12 and 24 weeks in all clinical trial participants. A subset of 11 active and 11 control participants will undergo a brain MRI with quantitative T₁ myelin water fraction at baseline and 24 weeks (exploratory remyelination endpoint).

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Oregon Health & Science University Institutional Review Board (#21045). Dissemination of findings will include peer-reviewed publications, conference presentations and media releases. The proposed study will inform the feasibility, study design and sample size for a fully powered clinical trial of aerobic exercise to promote remyelination in pwMS.

TRIAL REGISTRATION NUMBER

NCT04539002.

Combined progressive functional exercise effect on contactin-1 and contactin-2 level in mildly disabled persons with multiple sclerosis

BACKGROUND

Although contactin-1 and contactin-2 are known as two proteins involved in axonal regeneration, it is unclear whether these proteins are induced by exercise in persons with multiple sclerosis (PwMS).

OBJECTIVE

The aim of this study was to determine the serum levels of contactin-1 and contactin-2 in PwMS and to investigate the change of these markers with exercise.

METHODS

A total of 60 participants with relapsing-remitting MS were divided into groups by stratified randomization. The progressive functional exercise was applied to the intervention group. Participants in the control group continued the treatments and lives of the routines. Participants' contactin-1 and contactin-2, cognitive performance and aerobic capacities were evaluated.

RESULTS

The comparison of the pre-and post-study values of contactin-1 and contactin-2 showed significant differences only in the intervention group. The contactin-1 and contactin-2 values were similar between the groups before the exercise, whereas a significant difference was found in favor of the intervention group after the exercise. Paced Auditory Serial Addition Test-3 value increased significantly only in the intervention group.

CONCLUSION

With this study, it was shown for the first time that contactin-1 and contactin-2, which play an important role in axonal regeneration and axonal organization, can be increased by exercise.

The pathophysiology of motor fatigue and fatigability in multiple sclerosis

Multiple Sclerosis (MS) is a heterogeneous immune mediated disease of the central nervous system (CNS). Fatigue is one of the most common and disabling symptom of MS. It interferes with daily activities on the level of cognition and motor endurance. Motor fatigue can either result from lesions in cortical networks or motor pathways (“primary fatigue”) or it may be a consequence of detraining with subsequent adaptions of muscle and autonomic function. Programmed exercise interventions are used frequently to increase physical fitness in MS-patients. Studies investigating the effects of training on aerobic capacity, objective endurance and perceived fatigability have yielded heterogenous results, most likely due to the heterogeneity of interventions and patients, but probably also due to the non-uniform pathophysiology of fatigability among MS-patients. The aim of this review is to summarize the current knowledge on the pathophysiology of motor fatigability with special reference to the basic exercise physiology that underlies our understanding of both pathogenesis and treatment interventions.

High-intensity interval training in people with mild multiple sclerosis: a mixed-methods feasibility study

Background/Aims

High-intensity interval training has received increased attention as a mode of exercise, including as a therapy in clinical populations. This study investigated the acceptability of a high-intensity interval training intervention in people with mild multiple sclerosis.

Methods

Participants attended two sessions a week for the 6-week intervention. Each session consisted of 6–10 sets of 60-second high-intensity intervals interspersed with 120 seconds of recovery. The acceptability, intervention adherence and safety of the high-intensity interval training protocol and estimates of treatment effects (fitness, physical activity levels, fatigue and quality of life) were used to determine intervention feasibility. Qualitative interviews were used to explore the acceptability of the intervention.

Results

A total of 11 people with mild multiple sclerosis consented to participate in a 6-week high-intensity interval intervention. One participant dropped out of the intervention. The participants expressed apprehension before the intervention but attendance at the exercise sessions was high (87%). Participants experienced some symptom exacerbation following sessions, although none were serious. Improvements were seen in fitness, physical activity, fatigue and health-related quality of life.

Conclusions

The study findings suggest that high-intensity interval training is acceptable, safe and may offer disease-related benefits for the participants. Participants did experience some symptom exacerbation and further studies are needed to determine the long-term appeal of high-intensity interval training for people with mild multiple sclerosis.

Blood lactate concentrations during rest and exercise in people with Multiple Sclerosis: A systematic review and meta-analysis

BACKGROUND

Multiple Sclerosis (MS) is a chronic disorder which irreversibly damages axons within brain matter. Blood lactate concentration could be a biomarker of MS onset and progression, but no systematic review has yet sought to confirm or dispute the elevation and biomarker potential of blood lactate in people with MS (PwMS) or to consolidate understanding of lactate production during exercise in PwMS.

OBJECTIVE

To perform a systematic review and meta-analysis on blood lactate in PwMS during rest and exertion compared to Healthy Controls (HC) and following chronic exercise intervention.

METHODS

A systematic search of six electronic databases (PubMed, CINAHL, Science Direct, Cochrane Library, SPORTDiscus and PEDro) was performed on 10th April 2020. Mean, standard deviation and sample size for lactate measures at rest and during exercise were pooled to determine overall effect size using a random effects model.  The 20-point Appraisal tool for Cross-Sectional Studies was utilised to assess study quality and inherent risk of bias. To qualify for inclusion, studies had to include human adults (>18 years) with a confirmed clinical diagnosis of MS, be published in English, have undergone peer review, report absolute blood lactate values for data extraction, and if involving testing during/after exercise, to do so during bilateral exercise methods.

RESULTS

18 studies were qualitatively analysed and 15 studies quantitatively analysed. Outcome data was available for 1986 participants (n_MS = 1129). A total of 7 papers tested blood lactate during rest (Lactate_REST), 7 papers tested during sub-maximal intensity exercise (Lactate_SUB-MAX), and 8 papers tested during maximal intensity exercise (Lactate_MAX). Meta analyses showed elevated Lactate_REST and reduced Lactate_MAX in PwMS compared to HC, higher Lactate_MAX in lower EDSS-scoring PwMS compared to higher EDSS-scoring PwMS, and that Lactate_SUB-MAX decreases and Lactate_MAX increases in PwMS following a chronic exercise intervention. Qualitative analysis reported Lactate_REST to be reduced in PwMS following a chronic exercise intervention.

CONCLUSIONS

Lactate_REST is elevated in PwMS compared to HC. Lactate_MAX is lower in PwMS compared to HC and lower still in higher compared to lower EDSS-scoring groups of PwMS. Chronic exercise interventions have the potential to reduce Lacatate_SUB-MAX for a given power output and increase Lactate_MAX in PwMS compared to baseline values. Lactate_REST may be reduced in PwMS following a chronic exercise intervention but more research is required for confirmation. The results of this review were limited by small sample sizes and number of studies available for each testing condition, limited data available for potentially confounding/correlating factors (eg. VO₂ and power output) as well as heterogeneity of methodology adopted across studies, often due to lactate testing being a secondary outcome measure. PLS: Lactate levels in the blood are different during rest and at intense exercise levels in people with Multiple Sclerosis (MS) compared to healthy counterparts, with people with MS showing a smaller jump in lactate during intense exercise from a higher resting level. After exercising for at least 3 months, blood lactate levels during exercise may become more similar to the levels seen in people without Multiple Sclerosis, but more research is required to give a clearer picture of this. We can hopefully use blood lactate in future to measure the progression of MS in an individual as well as the effectiveness of their exercise programme.

Simplified indices of exercise tolerance in patients with multiple sclerosis and healthy subjects: A case-control study

Among patients with multiple sclerosis (MS), the impairment of exercise tolerance is closely related to disability. Maximal oxygen uptake (VO_2max ) is the gold standard to assess exercise tolerance in healthy subjects (HS). Among patients with MS, the accuracy of VO_2max measurement is often impaired because the patients are unable to reach the maximal exercise intensity due to interdependent factors linked to the disease (such as pathological fatigue, pain, lack of exercise habit, and lack of mobility). This study assesses the accuracy of simplified indices for assessing exercise tolerance, which are more suitable in patients with MS. They are simple in the way they are either measurable during submaximal exercise (oxygen uptake efficiency slopes (OUES), physical working capacity at 75% of maximal heart rate (PWC_75% ), oxygen consumption at a respiratory exchange ratio of 1 (VO₂ @RER1)) or not based on gas exchange analysis (peak work rate (PWR)-based predictive equation and PWC_75% ). All indices were significantly lower in the MS group compared to the HS group (P < .001). OUES appeared highly correlated (r > .70, P < .001) with VO_2peak , in both groups, without difference between groups. PWR-based prediction of VO_2peak showed a standard error of the estimate of 315 mL min^-1 in HS and 176 mL min^-1 in MS. PWC_75% did not correlate to VO_2peak in neither group. These findings suggest an impairment of exercise tolerance functions in mildly disabled persons with MS, independently from other factors. Submaximal indices involving gas exchange analysis or peakWR-based estimation of VO_2peak are usable to accurately assess exercise tolerance.

Do subcortical gray matter volumes and aerobic capacity account for cognitive-motor coupling in multiple sclerosis?

BACKGROUND

There is evidence of cognitive-motor coupling in multiple sclerosis (MS) such that the slowing of cognitive processing speed correlates with the worsening of walking speed and endurance.

OBJECTIVE

The current study first established the presence of cognitive-motor coupling and second examined the possibility that volumes of subcortical gray matter (SGM) structures and aerobic capacity might explain the coupling of cognitive and motor functions in persons with MS.

METHODS

We included data from 62 persons with clinically definite MS who underwent assessments of cognitive processing speed, walking performance, and aerobic capacity, and completed magnetic resonance imaging (MRI) within 7 days of the aforementioned assessments.

RESULTS

The strong correlations between cognitive processing speed and walking performance were attenuated in magnitude and not statistically significant when controlling for aerobic capacity alone and aerobic capacity and SGM volumes together. The associations between cognitive processing speed and walking performance remained statistically significant when controlling for SGM volumes alone.

CONCLUSION

Aerobic capacity may be an important target for neurorehabilitation-based approaches for managing co-occurring cognitive and motor dysfunction in MS.

The 2-minute walk test is not a valid method to determine aerobic capacity in persons with Multiple Sclerosis

BACKGROUND:

Walking tests, like the 2-minute fast walk test, are simple, inexpensive performance-based tests, and therefore seem attractive to estimate the aerobic fitness in people with chronic diseases.

OBJECTIVE:

To determine the criterion validity of the 2-minute fast walk test for estimating aerobic capacity in patients with Multiple Sclerosis (MS), by comparing it with the peak oxygen uptake (VO2peak in mL/kg/min) as measured by Cardiopulmonary Exercise Testing (CPET) on a cycle ergometer.

METHODS:

The 2 min fast walk test was performed on a marked indoor trajectory, using a static start protocol. Aerobic capacity (VO2peak, in mL/kg/min) was derived from CPET on a cycle ergometer. Criterion validity was tested by means of Pearson’s correlation coefficient and should be at least 0.70 for a good criterion validity of the 2 min walk test. Linear regression analysis was applied to more precisely estimate VO2peak.

RESULTS:

In total 141 people with severe MS-related fatigue (mean age 47.0 years (range 23–68 years), 73% women, median disease duration 7.8 years (range 0.3 – 28.7 years)) performed both tests. The distance walked in two minutes ranged from 52.0 to 290.0 m (mean 175.1 m, sd 44.9 m), while the VO2peak varied between 11.31 and 40.28 mL/kg/min (mean 22.52 mL/kg/min, sd 6.07 mL/kg/min). The correlation between the 2 min walk test and VO2peak was 0.441 (95% CI: 0.309–0.570). The absolute residual error in estimated VO2peak was 5.47 mL/kg/min.

CONCLUSIONS:

Due to the poor correlation found between the 2 min walk test and VO2peak, the 2-min walk test cannot be recommended as a valid alternative for estimating aerobic capacity in 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.

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.

Body mass index and cardiorespiratory fitness in persons with multiple sclerosis

OBJECTIVE

This study examined body fatness and its association with cardiorespiratory fitness (CRF) in persons with multiple sclerosis (pwMS) accounting for disability status.

MATERIALS AND METHODS

This study involved a secondary data analysis from a previous study of 62 pwMS. Body fatness was indirect measured as body mass index (BMI), and CRF was measured as peak oxygen consumption from an incremental exercise test with spirometry. Participants were allocated into 3 different groups based on established BMI categories (ie, normal, overweight, and obese), and data were analyzed using SPSS.

RESULTS

The average BMI was 27.0 (6.7) kg/m² , and CRF was 19.5 (7.2) mL/kg/min. There was an inverse correlation (pr = -.38 [-.57; -.14]; P = .003) between BMI and CRF controlling for age, sex, disease duration, and disability level. ANCOVA with linear contrast analysis revealed a statistical significant reduction in CRF between groups of different BMI categories; normal weight 20.8 (0.85); overweight 19.8 (1.13); and obese 16.9 (1.73) mL/kg/min; F (2, 55) = 3.33, P = .043; η²  = .11.

CONCLUSIONS

The findings suggest that BMI has a negative impact on CRF in pwMS, with a marked reduction in CRF for those classified as obese compared to those in the normal and overweight category.

High intensity interval training for people with multiple sclerosis: A systematic review

BACKGROUND

Aerobic high intensity interval training (HIIT) is safe in the general population and more efficient in improving fitness than continuous moderate intensity training. The body of literature examining HIIT in multiple sclerosis (MS) is expanding but to date a systematic review has not been conducted. The aim of this review was to investigate the efficacy and safety of HIIT in people with MS.

METHODS

A systematic search was carried out in September 2017 in EMBASE, MEDline, PEDro, CENTRAL and Web of Science Core collections using appropriate keywords and MeSH descriptors. Reference lists of relevant articles were also searched. Articles were eligible for inclusion if they were published in English, used HIIT, and included participants with MS. Quality was assessed using the PEDro scale. The following data were extracted using a standardised form: study design and characteristics, outcome measures, significant results, drop-outs, and adverse events.

RESULTS

Seven studies (described by 11 articles) were identified: four randomised controlled trials, one randomised cross-over trial and two cohort studies. PEDro scores ranged from 3 to 8. Included participants (n = 249) were predominantly mildly disabled; one study included only people with progressive MS. Six studies used cycle ergometry and one used arm ergometry to deliver HIIT. One study reported six adverse events, four which could be attributed to the intervention. The other six reported that there were no adverse events. Six studies reported improvements in at least one outcome measure, however there were 60 different outcome measures in the seven studies. The most commonly measured domain was fitness, which improved in five of the six studies measuring aspects of fitness. The only trial not to report positive results included people with progressive and a more severe level of disability (Extended Disability Status Scale 6.0-8.0).

CONCLUSION

HIIT appears to be safe and effective in increasing fitness in people with MS and low levels of disability. Further research is required to explore the effectiveness of HIIT in people with progressive MS and in those with higher levels of disability.

Prediction of oxygen uptake during walking in ambulatory persons with multiple sclerosis

People with multiple sclerosis (MS) have an increased rate of gross oxygen uptake (gross-VO2) during treadmill walking, and their gross-VO2 may further vary with walking impairment. This study attempted to develop an equation for predicting gross-VO2 from walking speed and an index of walking impairment in persons with MS and examine its accuracy. Gross-VO2 was measured with open-circuit spirometry in 43 persons with MS (47 +/- 9 yr; 38 women) during five treadmill walking trials, each lasting 6 min, at 2.0, 2.5, 3.0, 3.5, and 4.0 mph (0.89, 1.12, 1.34, 1.56, and 1.79 m/s). The 12-Item Multiple Sclerosis Walking Scale (MSWS-12) and the single-item Patient Determined Disease Steps scale (PDDS) provided indices of walking impairment. Multilevel modeling with random intercepts and slopes showed significant effects of speed and MSWS-12 on gross-VO2 (p </= 0.014; R(2) = 0.70). PDDS was not a significant predictor. Gross-VO2 estimated by the regression equation did not differ from actual gross-VO2 across speeds. Mean absolute prediction error across speeds was 9.1%. The Bland-Altman plot indicated zero mean difference between actual and predicted gross-VO2 with modest 95% confidence intervals. Therefore, speed and MSWS-12 score are jointly highly predictive of gross-VO2 during treadmill walking in persons with MS.

Aberrant peak lactate response in MS

BACKGROUND

The peak blood lactate response to an exhaustive exercise test in a number of chronic conditions has been shown to differ from that seen in healthy, untrained individuals. However, this has not been investigated for patients with multiple sclerosis (MS).

OBJECTIVE

The main objective was to determine and compare the peak blood lactate response to exercise and the maximal workload between two groups of MS patients with different illness severity.

METHODS

Twenty-five patients with a relapsing-remitting disease course (Group RR) and 41 patients with a secondary- or primary chronic progressive disease course (group CP) performed an exhaustive incremental bicycle ergometry. Peak blood lactate, maximal workload, peak oxygen consumption and maximal heart rate were measured.

RESULTS

The peak blood lactate levels and maximal workload differed significantly between the groups (group CP < group RR; p < 0.001). Furthermore spiroergometric peak performance markers in both groups were significantly lower than predicted for healthy age and sex matched untrained groups.

CONCLUSION

A reduced peak blood lactate response to exercise is a novel finding for MS patients. This calls into doubt if the lactate performance tests and lactate thresholds used for healthy individuals can be transferred to MS patients.

The Compact Wheelchair Roller Dynamometer

The equipment for evaluating the propulsion of a wheelchair is very complex and expensive. To validate a new dynamometer prototype for assessing the propulsion capacity of wheelchairs, 21 healthy subjects (age: 20.9±2.4 yr; weight: 68.9±7.9 kg; height: 174.0±7.1 cm; BMI: 22.7±2.5 kg·m ⁻² ) who do not normally require wheelchairs performed a sprint protocol for 20 s after a 1-min warm-up. The power and rotation data acquired by the prototype (both right and left sides) were compared with those of a reference system via high-speed videography (240 fps). The results showed high levels of accordance (95% CI), excellent values for the intraclass correlation coefficient (ICC: .99; P <0.00), no significant differences in the rotation ( P =0.91) and power ( P =0.94) between the methods. The proposed equipment met the validation criteria and thus can be applied as a new tool for assessing wheelchair propulsion.

Cross-validation of oxygen uptake prediction during walking in ambulatory persons with multiple sclerosis

BACKGROUND

An equation for predicting the gross oxygen uptake (gross-VO2) during walking for persons with multiple sclerosis (MS) has been developed. Predictors included walking speed and total score from the 12-Item Multiple Sclerosis Walking Scale (MSWS-12).

OBJECTIVE

This study examined the validity of this prediction equation in another sample of persons with MS.

METHODS

Participants were 18 persons with MS with limited mobility problems (42 ± 13 years; 14 women). Participants completed the MSWS-12. Gross-VO2 was measured with open-circuit spirometry during treadmill walking at 2.0, 3.0, and 4.0 mph (0.89, 1.34, and 1.79 m·s(-1)).

REULTS

Absolute percent error was small: 8.3 ± 6.1% , 8.0 ± 5.6% , and 12.2 ± 9.0% at 2.0, 3.0, and 4.0 mph, respectively. Actual gross-VO2 did not differ significantly from predicted gross-VO2 at 2.0 and 3.0 mph, but was significantly higher than predicted gross-VO2 at 4.0 mph (p <  0.001). Bland-Altman plots indicated nearly zero mean difference between actual and predicted gross-VO2 with modest 95% confidence intervals at 2.0 and 3.0 mph, but there was some underestimation at 4.0 mph.

CONCLUSIONS

Speed and MSWS-12 score provide valid prediction of gross-VO2 during treadmill walking at slow and moderate speeds in ambulatory persons with MS. However, there is a possibility of small underestimation for walking at 4.0 mph.

Effect of Exercise Training on Fitness in Multiple Sclerosis: A Meta-Analysis

OBJECTIVE

To provide a quantitative synthesis of randomized controlled trials (RCTs) examining the effect of exercise training on muscular and cardiorespiratory fitness in persons with multiple sclerosis (MS).

DATA SOURCES

Three electronic databases, PubMed, Google Scholar, and Web of Science, were searched for all relevant articles published up until October 2014.

STUDY SELECTION

Keywords included exercise or aerobic or strength or resistance training or cardiorespiratory and multiple sclerosis. Trials examining the effect of exercise training on muscular and/or cardiorespiratory fitness parameters were included.

DATA EXTRACTION

The initial search yielded 1501 articles; of these, 62 were reviewed in detail, and 20 RCTs met the inclusion criteria and provided enough data to compute effect sizes (ESs) (Cohen d). The meta-analyses was conducted using a random effects model to compute the overall or mean ES per fitness parameter.

DATA SYNTHESIS

The mean ES was .27 (SE=.05; 95% confidence interval [CI], .17-.38; z=5.05; P<.001) for muscular fitness outcomes and .47 (SE=.09; 95% CI, .30-.65; z=5.4; P<.001) for cardiorespiratory fitness outcomes. The weighted mean ES was not heterogeneous for muscular (Q13=11.09, P=.60, I(2)=.00) or cardiorespiratory (Q9=7.83, P=.55, I(2)=.00) fitness outcomes.

CONCLUSIONS

The cumulative evidence supports that exercise training is associated with changes in muscular (small in magnitude) and cardiorespiratory (moderate in magnitude) fitness outcomes in persons with MS. Such an indication of magnitude is important for clinical research and practice by providing an evidence-based estimate of the actual benefit that exercise training confers on physiological fitness.

Aerobic capacity in persons with multiple sclerosis: a systematic review and meta-analysis

BACKGROUND

Aerobic capacity (VO2max) is a strong health and performance predictor and is regarded as a key physiological measure in the healthy population and in persons with multiple sclerosis (PwMS). However, no studies have tried to synthesize the existing knowledge regarding VO2max in PwMS.

OBJECTIVES

The objectives of this study were to (1) systematically review the psychometric properties of the VO2max test; (2) systematically review the literature on VO2max compared with healthy populations; (3) summarize correlates of VO2max; and (4) to review and conduct a meta-analysis of longitudinal exercise studies evaluating training-induced effects on VO2max in PwMS.

DATA SOURCES AND STUDY SELECTION

A systematic literature search of six databases (PubMed, EMBASE, Cochrane Library, PEDro, CINAHL and SPORTDiscus) was performed. To be included, the study had to (1) enrol participants with definite MS according to defined criteria; (2) assess aerobic capacity (VO2max) by means of a graded exercise test to voluntary exhaustion; (3) had undergone peer review; and (4) be available in English, Danish or Dutch.

STUDY APPRAISAL AND SYNTHESIS METHODS

The psychometric properties of the VO2max test in PwMS were reviewed with respect to reliability, validity and responsiveness. Simple Pearson correlation analysis was used to assess the relation between key study characteristics and the reported mean VO2max. The methodological quality of the intervention studies was evaluated using the original 11-item Physiotherapy Evidence Database (PEDro) scale. A random coefficient model was used to summarize individual, weighted, standardized effects of studies that assessed the effects of exercise on aerobic capacity in PwMS.

RESULTS

A total of 40 studies, covering 165 healthy controls and 1,137 PwMS, fulfilled the inclusion criteria. VO2max testing in PwMS can be considered a valid measure of aerobic capacity, at least in PwMS having low-to-mild disability, and an ∼10% change between two tests performed on separate days can be considered the smallest reliable change (with 95% certainty) in VO2max in PwMS. The average body-weight-adjusted VO2max was significantly lower in PwMS (25.5 ± 5.2 mL·kg(-1)·min(-1)) compared with healthy controls (30.9 ± 5.4 mL·kg(-1)·min(-1)). The analysis of VO2max correlates revealed associations with a variety of outcomes covering all levels of the International Classification of Functioning, Disability and Health (ICF) model. The meta-analysis showed that aerobic training in PwMS may improve VO2max by as much as 3.5 mL·kg(-1)·min(-1).

CONCLUSIONS

A valid and reliable test can be performed, in at least ambulant PwMS, by the gold standard whole-body maximal exercise test. Aerobic capacity in PwMS is impaired compared with healthy people, and is significantly associated with factors on all levels of the ICF model, including disease severity. Aerobic training can improve aerobic capacity in PwMS to a degree that is associated with secondary health benefits.

Effects of vigorous walking exercise on core body temperature and inhibitory control in thermosensitive persons with multiple sclerosis

Aim: Acute, moderate intensity aerobic exercise might improve cognition in multiple sclerosis (MS), but it is unknown if increases in core body temperature (Ctemp) that negates those effects in thermosensitive persons with MS. Materials & methods: Fourteen fully ambulatory, thermosensitive persons with MS completed 20-min bouts of vigorous intensity treadmill walking exercise and seated quiet rest in a randomized, counterbalanced order. Ctemp was measured throughout each experimental condition. Inhibitory control (i.e., an executive function) was measured immediately prior to and following each condition. Results: Ctemp was elevated (˜0.6°C) with vigorous exercise versus quiet rest (p < 0.05). There further were pre-to-post improvements in inhibitory control for vigorous exercise versus quiet rest (ηp 2 = 0.29). Conclusion: Exercise-related increases in Ctemp do not nullify the potential acute exercise benefits on inhibitory control in MS.

Effects of Single Bouts of Walking Exercise and Yoga on Acute Mood Symptoms in People with Multiple Sclerosis

BACKGROUND

Little is known about the acute or immediate effects of walking exercise and yoga on mood in people with multiple sclerosis (MS). Such an examination is important for identifying an exercise modality for inclusion in exercise-training interventions that yields mood benefits in MS. We examined the effects of single bouts of treadmill walking and yoga compared with a quiet, seated-rest control condition on acute mood symptoms in MS.

METHODS

Twenty-four participants with MS completed 20 minutes of treadmill walking, yoga, or quiet rest in a randomized, counterbalanced order with 1 week between sessions. Participants completed the Profile of Mood States questionnaire before and immediately after each condition. Total mood disturbance (TMD) and the six subscales of the Profile of Mood States were analyzed using repeated-measures analysis of variance and paired-samples t tests.

RESULTS

There was a significant condition × time interaction on TMD scores (ηp (2) = 0.13). Walking and yoga conditions yielded comparable reductions in TMD scores. There was a significant condition × time interaction on vigor (ηp (2) = 0.23) whereby walking but not yoga yielded an improvement in vigor. There was a significant main effect of time on anger, confusion, depression, and tension (P < .05) but not on fatigue.

CONCLUSIONS

Walking and yoga yielded similar improvements in overall acute mood symptoms, and walking improved feelings of vigor. These effects should be further investigated in long-term exercise-training studies.

Step-rate cut-points for physical activity intensity in patients with multiple sclerosis: The effect of disability status

BACKGROUND

Evaluating the relationship between step-rate and rate of oxygen uptake (VO2) may allow for practical physical activity assessment in patients with multiple sclerosis (MS) of differing disability levels.

AIMS

To examine whether the VO2 to step-rate relationship during over-ground walking differs across varying disability levels among patients with MS and to develop step-rate thresholds for moderate- and vigorous-intensity physical activity.

MATERIALS AND METHODS

Adults with MS (N=58; age: 51 ± 9 years; 48 women) completed one over-ground walking trial at comfortable speed, one at 0.22 m · s(-1) slower, and one at 0.22 m · s(-1) faster. Each trial lasted 6 min. VO2 was measured with portable spirometry and steps with hand-tally. Disability status was classified as mild, moderate, or severe based on Expanded Disability Status Scale scores.

RESULTS

Multi-level regression indicated that step-rate, disability status, and height significantly predicted VO2 (p<0.05). Based on this model, we developed step-rate thresholds for activity intensity that vary by disability status and height. A separate regression without height allowed for development of step-rate thresholds that vary only by disability status.

CONCLUSION

The VO2 during over-ground walking differs among ambulatory patients with MS based on disability level and height, yielding different step-rate thresholds for physical activity intensity.

Aerobic fitness is associated with inhibitory control in persons with multiple sclerosis

Cognitive impairment is highly prevalent, disabling, and poorly managed in persons with multiple sclerosis (MS). Aerobic fitness might be a target of exercise training interventions for improving cognition in this population. It is unknown if the well-established pattern of associations between higher aerobic fitness and better inhibitory control in the general population exists among persons with MS. The current cross-sectional study examined the effects of aerobic fitness (VO2peak) on inhibitory control, using a modified flanker task, in 28 persons with MS and 28 healthy controls matched by age, sex, and body mass index. This involved performing bivariate correlations and hierarchical linear regression analyses on measures of aerobic fitness and inhibitory control. Persons with MS demonstrated lower VO2peak (d = -0.45), slower (d = 0.62-0.84), and less accurate (d = -0.60 to 0.71) performance on the flanker task than controls. VO2peak was similarly associated with reaction time measures of inhibitory control in the MS and control samples (ρ = -0.40 to 0.54). VO2peak (p < .01), but not group (p ≥ .08) (MS vs. control), predicted reaction time on the flanker task, irrespective of age, sex, and education. This supports the development of aerobic exercise interventions for improving reaction time on tasks of inhibitory control in persons with MS, much like what has been successfully undertaken in the general population.

Reliability and responsiveness of cardiopulmonary exercise testing in fatigued persons with multiple sclerosis and low to mild disability

Background

Peak oxygen uptake (VO₂peak) via cardiopulmonary exercise testing is considered the gold standard for testing aerobic capacity in healthy participants and people with various medical conditions. The reliability and responsiveness of cardiopulmonary exercise testing outcomes in persons with MS (PwMS) have not been extensively studied.

Objective

(1) to investigate the reliability of cardiopulmonary exercise parameters in PwMS; (2) to determine the responsiveness, in terms of the smallest detectable change (SDC), for each parameter.

Design

Two repeated measurements of cardiopulmonary exercise outcomes were obtained, with a median time interval of 16 days.

Methods

Thirty-two PwMS suffering from subjective fatigue performed cardiopulmonary exercise tests on a cycle ergometer, to voluntary exhaustion. We calculated the reliability, in terms of the intra-class correlation coefficient (ICC [2,k]; absolute agreement), and the measurement error, in terms of standard error of measurement (SEM) and SDC at individual (SDC_individual) and group level (SDC_group).

Results

The ICC for VO₂peak was 0.951, with an SEM of 0.131 L∙min⁻¹ and an SDC_individual of 0.364 L∙min⁻¹. When corrected for bodyweight, the ICC of VO₂peak was 0.933, with an SEM of 1.7 mL∙kg⁻¹∙min⁻¹ and in an SDC_individual of 4.6 mL∙kg⁻¹∙min⁻¹.

Limitations

Generalization of our study results is restricted to fatigued PwMS with a low to mild level of disability.

Conclusions

At individual level, cardiopulmonary exercise testing can be used reliably to assess physical fitness in terms of VO₂peak, but less so to determine significant changes. At group level, VO₂peak can be reliably used to determine physical fitness status and establish change over time.

Cardiorespiratory fitness and its association with thalamic, hippocampal, and basal ganglia volumes in multiple sclerosis

Background

There is little known about cardiorespiratory fitness and its association with volumes of the thalamus, hippocampus, and basal ganglia in multiple sclerosis (MS). Such inquiry is important for identifying a possible behavioral approach (e.g., aerobic exercise training) that might change volumes of deep gray matter (DGM) structures associated with cognitive and motor functions in MS.

Purpose

This study examined the association between cardiorespiratory fitness and volumes of the thalamus, hippocampus, and basal ganglia in MS.

Method

We enrolled 35 persons with MS who underwent a maximal exercise test for measuring cardiorespiratory fitness as peak oxygen consumption (VO_2peak) and brain MRI. Volumes of the thalamus, hippocampus, caudate, putamen, and pallidum were calculated from 3D T1-weighted structural brain images. We examined associations using partial (pr) correlations controlling for demographic and clinical variables.

Results

VO_2peak was significantly associated with composite scaled volumes of the caudate(pr = .47, p < .01), putamen (pr = .44, p < .05), pallidum (pr = .40, p < .05), and hippocampus (pr = .42, p < .05), but not thalamus (pr = .31, p = .09), when controlling for sex, age, disability, and duration of MS.

Conclusion

Our results provide novel evidence that cardiorespiratory fitness is associated with volumes of DGM structures that are involved in motor and cognitive functions in MS.

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We examine the association between cardiorespiratory fitness and deep gray matter structures in multiple sclerosis.

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Cardiorespiratory fitness was positively associated with volumes of basal ganglia nuclei in multiple sclerosis.

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Researchers should examine aerobic exercise training for improving brain health in multiple sclerosis.

Validity of maximal exercise testing in people with multiple sclerosis and low to moderate levels of disability

BACKGROUND

Cardiopulmonary exercise testing can be considered the gold standard for assessing cardiorespiratory fitness. Little is known about the criteria for maximal exercise testing in people with multiple sclerosis (MS) and how these criteria behave across different levels of neurological disability.

OBJECTIVE

The study objectives were to determine the criteria for maximal exercise testing across various levels of disability and to assess concomitant subgroup differences in measures related to the participant, disease, and function.

DESIGN

This was a cross-sectional study.

METHODS

Cardiopulmonary exercise testing was conducted with a sample of 56 participants with MS. Analysis of variance was used to assess the criteria in participants with MS and low, mild, and moderate levels of disability.

RESULTS

Mean peak oxygen consumption (V̇o2peak) was 21.4 (SD=7.1) mL·kg(-1)·min(-1). An oxygen consumption (V̇o2) plateau was seen in 37.5% of participants. A respiratory exchange ratio of 1.10 or greater was achieved by 69.6% of the participants, a maximal heart rate within 90% of their age-predicted maximal heart rate was achieved by 48.2% of the participants, and 23.2% of the participants perceived their exertion to be 18 or greater on the Borg Scale of Perceived Exertion (scores of 6-20). The values for achieved heart rate and incidence of a V̇o2 plateau were significantly lower in participants with moderate levels of disability than in those with mild levels of disability.

LIMITATIONS

The primary limitations of this study were its cross-sectional nature and relatively small sample of participants with moderate levels of disability.

CONCLUSION

The findings suggest that the outcome of cardiopulmonary exercise testing in people with MS and low to mild levels of disability (Expanded Disability Status Scale scores of ≤4.0) is a valid measure of cardiorespiratory fitness, whereas the outcome in people with moderate levels of disability (Expanded Disability Status Scale scores of >4.0) is most likely symptom limited.

Improved physical fitness correlates with improved cognition in multiple sclerosis

OBJECTIVE

To determine whether there is an association between improvements in objective measures of physical fitness and performance on cognitive tests in people with multiple sclerosis (MS).

DESIGN

Post hoc correlational analysis in which people demonstrating physical improvement were compared with those not demonstrating physical improvement.

SETTING

Individuals with MS residing in the community.

PARTICIPANTS

Adults with clinically confirmed MS (N=88) who participated in a controlled trial of a telephone-based health promotion intervention, chose to work on exercise, and completed the pre- and postintervention assessments.

INTERVENTIONS

Participants were measured for strength (isokinetic dynamometer), aerobic fitness (bicycle ergometer), and cognition (Paced Auditory Serial Addition Test [PASAT], Trail Making Test [TMT]) at baseline and 12 weeks later. Change in fitness was calculated by subtracting each participant's baseline score from the outcome score, and then transforming the difference to a z score. Individuals with a z score ≥1 on any fitness measure were placed in the physically improved group (n=25). All others were in the physically not improved group (n=57).

MAIN OUTCOME MEASURES TMT, PASAT RESULTS

After controlling for covariates (age, sex, ethnicity, education, disease activity, MS type), there was a significant group-by-time interaction, suggesting that cognitive functioning changed over time based on level of fitness. Participants in the physically improved group demonstrated improved performance on measures of executive functioning after 12 weeks of exercise.

CONCLUSIONS

The results of this study lend support to the hypothesis that change in fitness is associated with improved executive functioning in people with MS.

Delayed Recovery of Leg Fatigue Symptoms Following a Maximal Exercise Session in People With Multiple Sclerosis

Background. Fatigue is a chronic symptom for people with multiple sclerosis (PwMS). Objective. Symptoms of fatigue were investigated during and following a single exercise session. Methods. In all, 58 PwMS and 15 healthy, low-active controls performed a cycle ergometer incremental exercise test to voluntary exhaustion. Physiological intensity (expired air and heart rate), perceived breathlessness, and leg fatigue (Rating of Perceived Exertion [RPE] CR-10 Scale) were measured during and for 10 minutes following exercise. Measures of baseline disability (Barthel Index), activity (Physical Activity Scale for the Elderly), vitality (Subjective Vitality Scale), and general fatigue (Fatigue Severity Scale [FSS]) were recorded. Results. PwMS had reduced exercise capacity ( P = .00 to .01), but sensations of breathlessness and leg fatigue were the same at voluntary exercise termination in both groups ( P = .09). PwMS with fatigue (FSS ≥ 4) exhibited reduced exercise capacity ( P = .03 to .05) but reached the same physiological intensity, breathlessness, and leg fatigue symptoms at test termination as nonfatigued peers ( P = .16 to .59). During recovery, there was no difference in observed means between groups, except for leg RPE, which was higher in the MS group ( P = .047) and higher at 3 and 5 minutes after exercise in the fatigued MS group ( P = .02). Physiological markers and breathlessness recovered at the same rate in both groups ( P = .33 to .67). Conclusion. Monitoring leg fatigue symptoms during and through recovery from physical activities may help guide participation in physical activities for PwMS, particularly in people managing high levels of fatigue.

Physical fitness, walking performance, and gait in multiple sclerosis

BACKGROUND

Walking impairment is a prevalent, life-altering feature of multiple sclerosis (MS). There has been recent speculation that physiological deconditioning (i.e., reductions in aerobic capacity, balance, and muscular strength) contributes to walking and gait impairments in MS.

OBJECTIVE

This study examined the associations among aerobic capacity, balance, and lower-limb strength asymmetries, walking performance, and gait kinematics in 31 persons with MS and 31 matched controls.

METHODS

Participants underwent standard assessments of peak aerobic capacity, muscular strength (i.e., asymmetry between knee muscles), and balance. Walking performance was measured using the timed 25-ft walk (T25FW) and six-minute walk (6MW). Gait parameters were captured using a GaitRite™ electronic walkway.

RESULTS

Aerobic capacity, balance, and knee-extensor asymmetry were associated with walking performance and gait in persons with MS (r=.2-.6) and explained differences in walking and gait variables between MS and control groups (∆R(2)=.27-.34). Aerobic capacity and lower-limb strength asymmetries, but not balance, explained significant variance in walking performance and gait kinematics in the MS sample (R(2)=.32-.58).

CONCLUSIONS

Physiological deconditioning explains variability in walking disability in persons with MS and might represent a target of multimodal exercise training interventions for improving mobility outcomes in this population.

The benefits of exercise training in multiple sclerosis

Multiple sclerosis (MS) is an immune-mediated disease characterized by inflammatory demyelination and neurodegeneration within the CNS. This damage of CNS structures leads to deficits of body functions, which, in turn, affect patient activities, such as walking, and participation. The pathogenesis and resulting consequences of MS have been described as concepts within the International Classification of Functioning, Disability and Health (ICF) model--an international standard to describe and measure health and disability. Evidence suggests that exercise training in people with MS has the potential to target and improve many of the components outlined in the ICF model. Although the body of research examining the effects of exercise training on depression, cognition and participatory outcomes is not sufficiently developed, some preliminary evidence is promising. Exercise training is proposed to affect inflammation, neurodegeneration, and CNS structures, but current evidence is limited. In this Review, we discuss evidence from clinical trials that suggests beneficial effects of exercise training on muscle strength, aerobic capacity and walking performance, and on fatigue, gait, balance and quality of life. Issues with current studies and areas of future research are highlighted.