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

Age and asymmetry of corticospinal excitability, but not cardiorespiratory fitness, predict cognitive impairments in multiple sclerosis

Background

Cognitive impairment is a disabling and underestimated consequence of multiple sclerosis (MS), with multiple determinants that are poorly understood.

Objectives

We explored predictors of MS-related processing speed impairment (PSI) and age-related mild cognitive impairment (MCI) and hypothesized that cardiorespiratory fitness and corticospinal excitability would predict these impairments.

Methods

We screened 73 adults with MS (53 females; median [range]: Age 48 [21-70] years, EDSS 2.0 [0.0-6.5]) for PSI and MCI using the Symbol Digit Modalities Test and Montréal Cognitive Assessment, respectively. We identified six persons with PSI (No PSI, n = 67) and 13 with MCI (No MCI, n = 60). We obtained clinical data from medical records and self-reports; used transcranial magnetic stimulation to test corticospinal excitability; and assessed cardiorespiratory fitness using a graded maximal exercise test. We used receiver operator characteristic (ROC) curves to discern predictors of PSI and MCI.

Results

Interhemispheric asymmetry of corticospinal excitability was specific for PSI, while age was both sensitive and specific for MCI. MS-related PSI was also associated with statin prescriptions, while age-related MCI was related to progressive MS and GABA agonist prescriptions. Cardiorespiratory fitness was associated with neither PSI nor MCI.

Discussion

Corticospinal excitability is a potential marker of neurodegeneration in MS-related PSI, independent of age-related effects on global cognitive function. Age is a key predictor of mild global cognitive impairment. Cardiorespiratory fitness did not predict cognitive impairments in this clinic-based sample of persons with MS.

Objectively assessed physiological, physical, and cognitive function along with patient-reported outcomes during the first 2 years of Alemtuzumab treatment in multiple sclerosis: a prospective observational study

INTRODUCTION

In persons with multiple sclerosis (pwMS), little evidence exist on the effects of Alemtuzumab on physiological, physical, and cognitive function along with patient-reported outcomes, despite these domains are being rated as highly important. Therefore, our purpose was to perform a prospective observational study to examine these outlined outcomes during the first two years of Alemtuzumab treatment in pwMS.

METHODS

In n = 17 relapsing-remitting pwMS, physiological function [body composition; bone mineral content; muscle strength; aerobic capacity], physical function [6-min walk test (6MWT, primary outcome); timed 25 ft walk test (T25FWT); six spot step test (SSST); 9-step stair ascend (9SSA); timed up and go test (TUG); 5 × sit to stand test (5STS)], cognitive function [selective reminding test (SRT); symbol digit modalities test (SDMT)], and patient-reported outcomes [multiple sclerosis impact scale-29 (MSIS29); 12-item multiple sclerosis walking scale (MSWS12); modified fatigue impact scale (MFIS); hospital anxiety and depression scale (HADS)] were assessed prior to Alemtuzumab treatment initiation as well as 3, 6, 12, and 24 months into the treatment.

RESULTS

Improvements were observed at 24-month follow-up in T25FWT (+ 8%), SSST (+ 10%), SDMT (+ 5.2 points, 53% improved more than the clinical cut-off score) and SRT, whereas the primary outcome 6MWT, and all other remaining outcomes, remained stable throughout the Alemtuzumab treatment period.

CONCLUSION

The present findings suggest that Alemtuzumab treatment in relapsing-remitting pwMS can improve certain domains of physical function (short distance walking) and cognitive function (processing speed, memory), and furthermore stabilize physiological and physical function along with patient-reported outcomes.

TRIAL REGISTRATION

Registered at clinicaltrials.gov: NCT03806387.

Efficacy of high-intensity aerobic exercise on common multiple sclerosis symptoms

OBJECTIVES

Fatigue and walking impairment are disabling symptoms of multiple sclerosis (MS). We investigated the effects of progressive aerobic exercise (PAE) on fatigue, walking, cardiorespiratory fitness (VO₂ max), and quality of life in people with MS (pwMS).

MATERIALS & METHODS

Randomized controlled trial (1:1 ratio, stratified by sex) with a 24-week crossover follow-up and intention-to-treat analysis. Allocation to an exercise (24 weeks of PAE followed by self-guided physical activity) and a waitlist (24 weeks of habitual lifestyle followed by PAE) group. PAE comprised two supervised sessions per week; 30-60 min, 65-95% of maximum heart rate. Fatigue impact (Modified Fatigue Impact Scale; MFIS) and severity (Fatigue Severity Scale; FSS), walking ability (12-item MS Walking Scale; MSWS-12) and capacity (Six-Minute Walk Test; 6MWT, Six Spot Step Test; SSST), quality of life (Short Form 36 health survey; SF-36), and VO₂ max were measured at baseline, 24 weeks, and 48 weeks.

RESULTS

Eighty-six pwMS were enrolled. Following PAE between-group differences showed reductions in MFIS_total (-5.3 [95% CI: -10.9;0.4], point estimate >clinical relevance), MFIS_physical subscore (-2.8 [-5.6;-0.1]), and MFIS_psychosocial subscore (-0.9 [-1.6;-0.2]), and an increase in VO₂ max (+3.5 ml O₂ /min/kg [2.0;5.1]). MSWS-12 (-5.9 [-11.9; 0.2]) and 6MWT (+14 m [-5;33]) differences suggested potential small walking improvements. No changes observed in FSS, SSST, or SF-36.

CONCLUSIONS

In a representative sample of pwMS, PAE induced a clinically relevant reduction in fatigue impact, whereas small and no effects were seen for walking and quality of life, respectively. The results need confirmation in a future trial due to the study limitations.

Cardiorespiratory fitness and free-living physical activity are not associated with cognition in persons with progressive multiple sclerosis: Baseline analyses from the CogEx study

BACKGROUND

Aerobic exercise training (physical activity for improving cardiorespiratory fitness) represents a promising approach for managing cognitive impairment in multiple sclerosis (MS). However, there is limited evidence that levels of physical activity and fitness are associated with cognition in progressive MS.

OBJECTIVE

We examined associations among cardiorespiratory fitness, moderate-to-vigorous physical activity (MVPA), and cognitive performance in a large, international progressive MS sample.

METHODS

Two hundred forty European and North American persons with progressive MS underwent cardiorespiratory fitness measurement on a recumbent stepper, wore an ActiGraph GT3X + accelerometer for 7 days for measuring MVPA, and underwent the Brief International Cognitive Assessment in MS.

RESULTS

Cardiorespiratory fitness was not significantly correlated with Symbol Digit Modalities Test (SDMT; r = -0.01; r = -0.04), California Verbal Learning Test-II (CVLT-II; r = 0.05; r = 0.05), or Brief Visuospatial Memory Test-Revised (BVMT-R; r = -0.14; r = -0.14) z-scores controlling for age, sex, and education. MVPA and SDMT (r = 0.05), CVLT-II (r = -0.07), and BVMT-R (r = 0.01) z-scores were not significantly correlated.

CONCLUSION

Cardiorespiratory fitness and MVPA were not associated with cognition in this large progressive MS sample, yet these outcomes represent critical manipulation checks for documenting the success of the CogEx trial. This highlights the importance of examining other exercise-related mechanisms-of-action for improving cognition in progressive MS.

Cortical diffusion kurtosis imaging and thalamic volume are associated with cognitive and walking performance in relapsing-remitting multiple sclerosis

BACKGROUND

In multiple sclerosis (MS), pronounced neurodegeneration manifests itself as cerebral gray matter (GM) atrophy, which is associated with cognitive and physical impairments. Microstructural changes in GM estimated by diffusion kurtosis imaging (DKI) may reveal neurodegeneration that is undetectable by conventional structural MRI and thus serve as a more sensitive marker of disease progression.

OBJECTIVE

The primary objective was to investigate the relationships between morphological and diffusional properties in cerebral GM and physical and cognitive performance in relapsing-remitting MS (RRMS) patients. A secondary objective was to investigate the relationship between GM microstructure and white matter (WM) injury, estimated by the volume of WM lesions.

METHODS

Sixty-seven RRMS patients performed the brief repeatable battery of neuropsychological tests (BRB-N), the 6-minute walk test (6MWT), the six spot step test (SSST), and underwent MRI scans using structural and DKI protocols. GM volumetrics and DKI measurements were analyzed in the cortex and deep GM structures using a general linear model with demographics, physical- and cognitive performance as covariates.

RESULTS

Mean diffusivity (MD) in the cortex was associated with the SSST, 6MWT, information processing, global cognitive performance, and volume of WM lesions. In addition, thalamic volume was associated with SSST (r² = 0.21, 6MWT (r² = 0.18), information processing (r² = 0.21), and WM lesion volume (r² = 0.60).

CONCLUSION

Cortical diffusion and thalamic volume are associated with walking and cognitive performance in RRMS patients and are highly affected by the presence of WM lesions.

Do baseline cognitive status, participant specific characteristics and EDSS impact changes of cognitive performance following aerobic exercise intervention in multiple sclerosis?

PURPOSE

Cognitive impairment is a common symptom of multiple sclerosis (MS). Physical exercise represents a promising non-pharmacological therapy option, however, potential predictors for successful cognitive improvements mediated by exercise remain to be elucidated in order to optimize targeted exercise training regimens. One of the most promising exercise training regime in this context is high-intensity interval training (HIIT). Against this backdrop, this study i) analysed the effects of a three-week HIIT compared to moderate continuous exercise on cognitive performance and ii) investigated potential predictors for changes of cognitive performance following a three-week aerobic exercise intervention.

METHODS

Datasets of two randomized controlled trials (RCT) were pooled, resulting in a total sample size of n = 130 persons with MS (pwMS) who either performed HIIT or moderate intensity continuous (MCT) exercise 3-5x/ week for three weeks. Cognitive performance was assessed with the Brief International Cognitive Assessment for MS. I) Potential within (time) and interaction (time x group) effects for cognitive performance were investigated with univariate analyses of covariance (ANCOVA). II) Potential predictors for changes of cognitive performance were assessed by multiple linear regression models.

RESULTS

ANCOVA revealed significant time effects for all cognitive outcomes and a time x group interaction for verbal learning (p=.045), with HIIT inducing superior effects compared to moderate continuous exercise (MCT). Cognitive status (impaired/intact cognition) (p= .008) and exercise regime (HIIT/moderate continuous) (p=.040) influenced changes of verbal learning. Cognitive status (p=.006) and EDSS (p=.048) affected changes of visuospatial memory in pwMS. The models accounted for 5.4% and 7.7% of the variance.

CONCLUSION

Cognitive status, exercise regime and EDSS potentially impact changes of specific cognitive domains following aerobic exercise. Further predictors for changes of cognitive performance following an aerobic exercise intervention need to be investigated as current results accounted only for a limited amount of variance. RCTs that investigate effects of physical exercise on cognitive performance should include only pwMS with impaired baseline cognitive performance. To better understand the impact of exercise on cognitive performance, it is furthermore recommendable to include cognitive assessments in clinical routine.

Efficacy of High-Intensity Aerobic Exercise on Brain MRI Measures in Multiple Sclerosis

OBJECTIVE

To determine whether 24 weeks of high-intensity progressive aerobic exercise (PAE) affects brain MRI measures in people with multiple sclerosis (MS).

METHODS

We conducted a randomized, controlled, phase 2 trial (with a crossover follow-up) including an exercise group (supervised PAE followed by self-guided physical activity) and a waitlist group (habitual lifestyle followed by supervised PAE). Mildly to severely impaired patients with MS aged 18-65 years were randomized (1:1). The primary outcome was percentage brain volume change (PBVC) after 24 weeks, analyzed using the intention-to-treat principle.

RESULTS

Eighty-six participants were recruited. PBVC did not change over the intervention period (mean between-group change +0.12%, 95% confidence interval [CI] -0.27 to 0.51, p = 0.55). In contrast, cardiorespiratory fitness (+3.5 mL O₂/min/kg, 2.0 to 5.1, p < 0.01) and annualized relapse rate (0.00, 0.00-0.07 vs +0.45, 0.28 to 0.61, p < 0.01) improved in the exercise group.

CONCLUSION

These findings do not support a neuroprotective effect of PAE in terms of total brain atrophy in people with MS and it did not lead to a statistically significant difference in gray matter parenchymal fraction. PAE led to improvements in cardiorespiratory fitness and a lower relapse rate. While these exploratory findings cautiously support PAE as a potential adjunct disease-modifying treatment in MS, further investigations are warranted.

CLINICALTRIALSGOV IDENTIFIER

NCT02661555.

CLASSIFICATION OF EVIDENCE

This study provides Level I evidence that 24 weeks of high-intensity PAE did not elicit disease-modifying effects in PBVC in people with MS. Exploratory analyses showed that PAE may reduce relapse rate.

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.

Correlations of health status indicators with perceived neuropsychological impairment and cognitive processing speed in multiple sclerosis

BACKGROUND

Comorbidity and health behaviours may explain heterogeneity regarding cognitive performance in multiple sclerosis. Patient-reported cognitive difficulties have impact but do not consistently correlate with objective cognitive performance. Our study aims to investigate whether health status indicators including comorbidities, body mass index, physical activity, smoking, sleeping behaviour and consumption patterns for fish, alcohol and caffeinated drinks are associated with measures of subjective and objective cognitive performance.

METHODS

Survey data on self-reported cognitive performance, assessed with the MS Neuropsychological Screening Questionnaire (MSNQ), were related to the presence of arterial hypertension, diabetes mellitus, cardiovascular and chronic renal diseases, hypercholesterolemia, depression based on 2-question screening tool, health and consumption behaviors. We included the Symbol Digit Modalities Test when available within 6 months as an objective, performance-based metric of cognitive processing speed. We investigated the interrelation between all variables with a Spearman correlation matrix and corrected for multiple testing. Regression models were built and controlled for age, sex and phenotype.

RESULTS

We used available data from 751 patients with definite MS, including 290 SDMT scores within a time window of 6 months, to study relations between variables. MSNQ and SDMT scores were not significantly correlated. Correlation patterns for subjective and objective performance differed. Age, disease duration and physical disability correlated with SDMT scores only. Regression analyses could be performed for MSNQ scores in 595/751 (79.2%) and for SDMT scores in 234/751 (31.2%) participants. After restricting variables to avoid collinearity and adjusting for the number of variables, regression models explained 15% of the variance for subjective and 14% of the variance for objective cognitive performance. A higher number of physical comorbidities, reporting depressive symptoms, sleeping 9 h or more and daily use of sleeping medication were associated with lower subjective cognitive performance, whereas increasing age was associated with reduced processing speed. These associations persisted after correction for multiple testing.

CONCLUSION

Increasing age is associated with reduced cognitive processing speed whereas comorbidities and sleep behaviors contribute to subjective cognitive performance.

Effect of High-Intensity Exercise on Multiple Sclerosis Function and Phosphorous Magnetic Resonance Spectroscopy Outcomes

PURPOSE

We determined if a high-intensity aerobic exercise program would be safe, improve expected fitness and clinical outcomes, and alter exploratory phosphorous magnetic resonance spectroscopy (P MRS) outcomes in persons with multiple sclerosis (PwMS).

METHODS

This open-label prospective pilot study compared two cohorts of ambulatory PwMS matched for age, sex and V˙O2max. Cohorts underwent 8 wk of high-intensity aerobic exercise (MS-Ex, n = 10) or guided stretching (MS-Ctr, n = 7). Aerobic exercise consisted of four 30-min sessions per week while maintaining ≥70% maximal HR. Changes in cardiorespiratory fitness, clinical outcomes, and P MRS of tibialis anterior (TA) muscle and brain were compared. Cross-sectional P MRS comparisons were made between all MS participants and a separate matched healthy control population.

RESULTS

The MS-Ex cohort achieved target increases in V˙O2max (mean, +12.7%; P = <0.001, between-group improvement, P = 0.03). One participant was withdrawn for exercise-induced syncope. The MS-Ex cohort had within-group improvements in fat mass (-5.8%; P = 0.04), lean muscle mass (+2.6%; P = 0.02), Symbol Digit Modalities Test (+15.1%; P = 0.04), and cognitive subscore of the Modified Fatigue Impact Scale (-26%; P = 0.03), whereas only the physical subscore of the Modified Fatigue Impact Scale improved in MS-Ctr (-16.1%; P = 0.007). P MRS revealed significant within-group increases in MS-Ex participants in TA rate constant of phosphocreatine (PCr) recovery (+31.5%; P = 0.03) and adenosine triphosphate/PCr (+3.2%; P = 0.01), and near significant between-group increases in TA PCr recovery rate constant (P = 0.05) but no significant changes in brain P MRS after exercise. Cross-sectional differences existed between MS and healthy control brain PCr/inorganic phosphate (4.61 ± 0.44, 3.93 ± 0.19; P = 0.0019).

CONCLUSIONS

High-intensity aerobic exercise in PwMS improved expected cardiorespiratory and clinical outcomes but provoked one serious adverse event. The P MRS may serve to explore underlying mechanisms by which aerobic exercise exerts cerebral benefits.

Identifying risk factors for cognitive issues in multiple sclerosis

INTRODUCTION

Cognitive impairment (CI) in Multiple Sclerosis (MS) has progressively regained clinical and research interest and is currently recognized as a debilitating and burdensome problem for these patients. Studying risk and protecting factors that may influence the development and course of CI is currently an area of increasing interest, due to the potential for preventive strategies. Areas covered: In this narrative review the authors briefly addressed the physiopathologic basis, assessment and management of CI in MS and then focused on identifying modifiable and not modifiable risk factors for CI in MS, providing an overview of the current knowledge in the field and indicating avenues for future research. Expert opinion: Improving our understanding of potentially modifiable environmental and lifestyle risk factors or protective factors for CI is important in order to prompt preventive strategies and orient patient counselling and clinical management. To this aim, we need to enhance the current level of evidence linking lifestyle factors to cognition and evaluate some factors that were only preliminary addressed in research. Moreover, we need to explore the role of each factor into the subject cognitive outcome, next to the possible interactions between different environmental factors as well as between environmental and genetic factors.