Walking endurance in multiple sclerosis: Meta-analysis of six-minute walk test performance

Cross-sectional, comparative study of health-related quality of life across the adult lifespan in multiple sclerosis

PURPOSE

This study examines the independent and interactive effects of age and multiple sclerosis (MS) on health-related quality of life (HRQOL).

MATERIALS AND METHODS

The sample included persons with MS (n = 207) and healthy controls (HCs; n = 99) divided into three age groups (young, middle-aged, and older adults) who completed a battery of questionnaires, including the 36-item Short-Form Health Survey (SF-36) as a measure of HRQOL. The SF-36 yielded scores for the Physical Component Summary (PCS) (i.e. physical HRQOL) and Mental Component Summary (MCS) (i.e. mental HRQOL). The data were analyzed using two-way MANOVA.

RESULTS

There was no interaction between age and disease status on HRQOL, but there were significant main effects of age and disease status on HRQOL. HRQOL was significantly lower in participants with MS than HCs, regardless of age. Physical HRQOL was lower, whereas mental HRQOL was higher across age groups.

CONCLUSION

The findings suggest that future research should develop behavioral and rehabilitation approaches that are applicable for improving HRQOL across the lifespan in persons with MS, particularly for physical HRQOL in older adults with MS.

Walking and physical performance in black and white adults with multiple sclerosis controlling for social determinants of health

BACKGROUND

There is evidence for reduced walking and physical performance in persons with multiple sclerosis (MS) compared with healthy controls (HCs). There is further evidence suggesting increased overall mobility disability in Black persons with MS compared with White counterparts, yet little is known about the interplay of social determinants of health (SDOH) when considering differences in walking and physical performance.

PURPOSE

This cross-sectional, comparative study examined differences in walking and physical performance in Black and White persons with MS and HCs (MS Status), statistically controlling for SDOH.

METHODS

The study sample consisted of 208 persons with MS (141 White participants and 67 Black participants) and 95 HCs (59 White participants and 36 Black participants). Walking and physical function were measured using timed 25-foot walk (T25FW), six-minute walk (6MW), timed-up-and-go (TUG), and short physical performance battery (SPPB). We examined the differences in the walking and physical functions as a function of MS Status (MS vs. HCs) and Race (Black vs. White) using Multivariate Analysis of Covariance, controlling for age, sex, marital status and SDOH (i.e., education, employment, income).

RESULTS

There were no significant interactions between MS Status and Race on the outcomes, and the main effects of MS Status and Race remained statistically significant, controlling for SDOH and covariates. The main effects indicated significant lower T25FW (F = 34.6, p < .001, Ƞp2 = 0.11), 6MW (F = 58.5, p < .001, Ƞp2 = 0.18), TUG (F = 22.1, p < .001, Ƞp2 = 0.08), and SPPB (F = 25.2, p < .001, Ƞp2 = 0.09) performance for MS than HCs, and lower T25FW (F = 15.5, p < .001, Ƞp2 = 0.05), 6MW (F = 11.6, p < .001, Ƞp2 = 0.04), and TUG (F = 4.1, p < .05, Ƞp2 = 0.02) performance in Black than White samples.

CONCLUSIONS

We conclude that MS Status and Race independently influence walking and physical performance even after accounting for SDOH, and Black persons with MS have compromised walking and physical performance, perhaps necessitating focal rehabilitation.

Comorbid Conditions and Physical Function in Adults With Multiple Sclerosis

OBJECTIVE

We examined the total number of comorbid conditions as a correlate of physical function in persons with multiple sclerosis (MS). We further identified the presence of common comorbid conditions and examined physical function outcomes based on presence or absence of the comorbid conditions in persons with MS.

DESIGN

Cross-sectional, comparative study.

SETTING

University-based laboratory.

PARTICIPANTS

Two hundred seven persons with MS (N=207) completed the study.

MAIN OUTCOME MEASURES

Participants provided demographic, clinical, and comorbidity information. Participants then completed the 6-minute walk (6MW), timed 25-foot walk (T25FW), timed Up and Go (TUG), and short physical performance battery (SPPB).

INTERVENTIONS

Not applicable.

RESULTS

The number of comorbid conditions was associated with 6MW, T25FW, TUG, and SPPB scores (all P≤.001). Persons with MS who had hypertension performed worse on the 6MW, T25FW, TUG, and SPPB than persons without hypertension. Persons who had osteoarthritis performed worse on the 6MW, T25FW, and SPPB than persons without osteoarthritis.

CONCLUSIONS

The results demonstrate that persons who report more comorbid conditions have worse physical function, and this may largely be associated with hypertension or osteoarthritis. There are opportunities for the design of behavioral interventions that target physical activity and/or diet for improving physical function via comorbid conditions in persons with MS.

Between-Day Reliability of the Gait Characteristics and Their Changes During the 6-Minute Walking Test in People With Multiple Sclerosis

BACKGROUND

Gait characteristics and their changes during the 6-minute walking test (6MWT) in people with multiple sclerosis (pwMS) have been described in the literature, which one may refer to as walking fatigability in the body function level of the International Classification of Functioning, Disability, and Health. However, whether these metrics are reliable is unknown.

OBJECTIVE

To investigate the between-day reliability of the gait characteristics and their changes in pwMS and healthy controls (HCs).

METHODS

Forty-nine pwMS (EDSS 4.82 ± 1.22 and 54.7 ± 9.36 years) and 23 HCs (50.6 ± 6.1 years) performed the 6MWT, as fast as possible but safely while wearing Inertial Measurement Units. Gait characteristics were measured in the pace, rhythm, variability, asymmetry, kinematics, coordination, and postural control domains and were obtained in intervals of 1 minute during the 6MWT. In addition, gait characteristics change in the last minute compared with the first minute were calculated for all gait variables using a fatigability index (ie, distance walking index). The intraclass correlation coefficient (ICC), Bland-Altman Plots, and Standard error of measurement were applied to investigate reliability.

RESULTS

Reliability of gait characteristics, minute-by-minute, and for their changes (ie, using the fatigability index) ranged from poor to excellent (pwMS: ICC 0.46-0.96; HC: ICC 0.09-0.97 and pwMS: ICC 0-0.72; HC: ICC 0-0.77, respectively).

CONCLUSION

Besides coordination, at least 1 variable of each gait domain showed an ICC of moderate or good reliability for gait characteristics changes in both pwMS and HC. These metrics can be incorporated into future clinical trials and research on walking fatigability.Clinical Trial Registration: NCT05412043.

Progression events defined by home-based assessment of motor function in multiple sclerosis: protocol of a prospective study

Background

This study relates to emerging concepts of appropriate trial designs to evaluate effects of intervention on the accumulation of irreversible disability in multiple sclerosis (MS). Major starting points of our study are the known limitations of current definitions of disability progression by rater-based clinical assessment and the high relevance of gait and balance dysfunctions in MS. The study aims to explore a novel definition of disease progression using repeated instrumental assessment of relevant motor functions performed by patients in their home setting.

Methods

The study is a prospective single-center observational cohort study with the primary outcome acquired by participants themselves, a home-based assessment of motor functions based on an RGB-Depth (RGB-D) camera, a camera that provides both depth (D) and color (RGB) data. Participants are instructed to perform and record a set of simple motor tasks twice a day over a one-week period every 6 months. Assessments are complemented by a set of questionnaires. Annual research grade assessments are acquired at dedicated study visits and include clinical ratings as well as structural imaging (MRI and optical coherence tomography). In addition, clinical data from routine visits is provided semiannually by treating neurologists. The observation period is 24 months for the primary endpoint with an additional clinical assessment at 27 month to confirm progression defined by the Expanded Disability Status Scale (EDSS). Secondary analyses aim to explore the time course of changes in motor parameters and performance of the novel definition against different alternative definitions of progression in MS. The study was registered at Deutsches Register für Klinische Studien (DRKS00027042).

Discussion

The study design presented here investigates disease progression defined by marker-less home-based assessment of motor functions against 3-month confirmed disease progression (3 m-CDP) defined by the EDSS. The technical approach was chosen due to previous experience in lab-based settings. The observation time per participant of 24, respectively, 27 months is commonly conceived as the lower limit needed to study disability progression. Defining a valid digital motor outcome for disease progression in MS may help to reduce observation times in clinical trials and add confidence to the detection of progression events in MS.

Automatic Assessment of the 2-Minute Walk Distance for Remote Monitoring of People with Multiple Sclerosis

The aim of this study was to investigate the feasibility of automatically assessing the 2-Minute Walk Distance (2MWD) for monitoring people with multiple sclerosis (pwMS). For 154 pwMS, MS-related clinical outcomes as well as the 2MWDs as evaluated by clinicians and derived from accelerometer data were collected from a total of 323 periodic clinical visits. Accelerometer data from a wearable device during 100 home-based 2MWD assessments were also acquired. The error in estimating the 2MWD was validated for walk tests performed at hospital, and then the correlation (r) between clinical outcomes and home-based 2MWD assessments was evaluated. Robust performance in estimating the 2MWD from the wearable device was obtained, yielding an error of less than 10% in about two-thirds of clinical visits. Correlation analysis showed that there is a strong association between the actual and the estimated 2MWD obtained either at hospital (r = 0.71) or at home (r = 0.58). Furthermore, the estimated 2MWD exhibits moderate-to-strong correlation with various MS-related clinical outcomes, including disability and fatigue severity scores. Automatic assessment of the 2MWD in pwMS is feasible with the usage of a consumer-friendly wearable device in clinical and non-clinical settings. Wearable devices can also enhance the assessment of MS-related clinical outcomes.

The effect of balance, walking capacity, and fear of falling on the level of community integration in individuals with Multiple Sclerosis: A cross-sectional study

BACKGROUND

Social participation levels of individuals with Multiple Sclerosis (iwMS) are lower than those of healthy individuals.

OBJECTIVE

This study aimed to evaluate to which extent the walking capacity, balance, and fear of falling (FoF) affect the community integration levels of iwMS.

METHODS

Thirty-nine iwMS were evaluated for their participation levels [The Community Integration Questionnaire (CIQ)], walking capacity [The Six-Minute Walk Test (6MWT)], balance [Kinesthetic Ability Trainer (SportKAT®)], and FoF [The Modified Falls Efficacy Scale (MFES)]. Correlation and regression analyses were performed to detect the effects of SportKAT®, 6MWT, and MFES on CIQ.

RESULTS

CIQ scores were significantly correlated with 6MWT (p = .043) and MFES (p = .005) scores, while CIQ was not related with static (for two feet test p = .356, for right single-leg stance test p = .412, for left single-leg stance test p = .730) and dynamic balance (for clockwise test p = .097, for counterclockwise test p = .540) measured with the SportKAT®. It was found that CIQ could be predicted by 6MWT and MFES at the level of 16% and 25%, respectively.

CONCLUSION

FoF and walking capacity are associated with community integration in iwMS. Therefore, physiotherapy and rehabilitation programs of iwMS should be combined with treatment goals to increase community integration, balance, and gait and decrease the disability and FoF from an early stage. Comprehensive studies examining other factors that may impact participation in iwMS with different levels of disability are needed.

Locomotor Strategy to Perform 6-Minute Walk Test in People with Multiple Sclerosis: A Prospective Observational Study

Two-thirds of people with Multiple Sclerosis (PwMS) have walking disabilities. Considering the literature, prolonged tests, such as the 6 min walk test, better reflect their everyday life walking capacities and endurance. However, in most studies, only the distance traveled during the 6MWT was measured. This study aims to analyze spatio-temporal (ST) walking patterns of PwMS and healthy people in the 6MWT. Participants performed a 6MWT with measures of five ST variables during three 1 min intervals (initial: 0'-1', middle: 2'30″-3'30″, end: 5'-6') of the 6MWT, using the GAITRite system. Forty-five PwMS and 24 healthy people were included. We observed in PwMS significant changes between initial and final intervals for all ST parameters, whereas healthy people had a rebound pattern but the changes between intervals were rather negligible. Moreover, ST variables' changes were superior to the standard measurement error only for PwMS between initial and final intervals for all ST parameters. This result suggests that the modification in PwMS' walking pattern is effectively due to their walking ability and not to a measurement, and suggests that PwMS could not manage their walking efficiently compared to healthy people, who could maintain their rhythm throughout the 6MWT. Further studies are needed to detect these patterns changes in the early evolution of the disease, identify clinical determinants involved in PwMS' walking pattern, and investigate whether interventions can positively impact this pattern.

Physical function across the lifespan in adults with multiple sclerosis: An application of the Short Physical Performance Battery

BACKGROUND

Multiple sclerosis (MS) typically has its onset in early and middle adulthood, but the population is steadily becoming more dominated by older adults. One of the primary consequences of both MS and aging involves declines of lower extremity physical function and mobility. This cross-sectional study compared physical function status based on Short Physical Performance Battery (SPPB) summary and component scores between persons with MS and healthy controls across 6 age groups. We further examined associations between SPPB summary scores and component scores as well as associations between summary scores and measures of physical and cognitive function for identifying the strongest correlates of SPPB summary scores.

METHODS

The study involved secondary analysis of cross-sectional data from multiple studies. Ambulatory adults with MS who were relapse-free for the last 30 days were recruited, and controls were recruited based on similar criteria to adults with MS except without the diagnosis of MS or relapses. The sample of 345 persons with MS and 174 controls completed questionnaires regarding demographic and clinical information and underwent assessments of physical and cognitive function including the SPPB, 6-Minute Walk, Timed 25-Foot Walk, Symbol Digit Modalities Test, California Verbal Learning Test-Second Edition, and Brief Visuospatial Memory Test-Revised.

RESULTS

The two-way ANOVA indicated a main effect of MS status (F(5,500)=34.74, p<.01, η²=0.065), a main effect of age (F(1,500)=3.88, p<.01, η²=0.037), and no MS status by age interaction (F(5,500)=1.20, p=.31, η²=0.012) on SPPB scores. The bivariate correlation analysis indicated that summary SPPB scores were associated with component SPPB scores in the overall samples of persons with MS (r_s=0.71 to 0.83) and controls (r_s=0.42 to 0.91) as well as within most age groups of MS (r_s=0.63 to 0.91) and controls (r_s=0.34 to 1.00). The associations between SPPB scores and physical function outcomes were larger in the sample of persons with MS (r_s=-0.72 to 0.76) than controls (r_s=-0.47 to 0.48). SPPB scores were further significantly associated with scores on cognitive outcomes in persons with MS (r_s=0.31 to 0.43), whereas these associations were weaker in controls (r_s=0.09 to 0.32). Overall, the associations between SPPB scores and physical function outcomes were stronger than the associations between SPPB scores and cognitive function outcomes.

CONCLUSION

Overall, MS status and aging have additive effects on physical function, and the summary SPPB score may be driven by a specific component within each age group. SPPB scores may be driven more by mobility rather than cognition, and are consistent with cognitive-motor coupling in MS. The novelty of this study provides evidence of worsening physical function based on the application of the SPPB and its scores across the lifespan in persons with MS and controls, and this has important implications particularly given the increasing prevalence of older adults with MS.

Energy expenditure and perceived effort during uphill and downhill walking in people with multiple sclerosis

BACKGROUND

Walking on different slopes is a common daily activity for many ambulatory people with multiple sclerosis (pwMS) AIM: Investigate energy expenditure measures of walking on level, uphill and downhill slopes in pwMS.

DESIGN

Observational case-control study.

SETTING

Sheba Multiple Sclerosis Center, Tel-Hashomer, Israel.

POPULATION

Eighteen pwMS; 10 women and 8 men, aged 39.7 (SD=6.8), mean EDSS was 2.9 (SD=1.2) and 23 healthy adults; 8 women and 15 men, aged 37.1 (S.D.=5.3).

METHODS

Energy expenditure values were obtained via a metabolic device during four conditions: sitting, comfortable walking, uphill and downhill walking. Each walking trial, obtained on a treadmill, lasted 6-min and were separated by10-min recovery intervals.

RESULTS

For both pwMS and healthy controls, the O2 rate and O2 cost was higher during uphill walking compared to level walking and lower during downhill walking compared with level walking. O2 rate and net O2 cost during uphill walking was lower in pwMS compared with the healthy controls. The most demanding effort was during uphill walking, with pwMS rating it more demanding compared with the healthy controls.

CONCLUSIONS

Perceived effort of walking on different slopes is not consistent with changes in the energy expenditure values in pwMS.

CLINICAL REHABILITATION IMPACT

pwMS describe the effort of walking on different slopes higher than normal, regardless of the energy expenditure values.

Psychometric properties of the Chinese (Cantonese) version of the Upper Extremity Functional Index in people with chronic stroke

Objective

To culturally adapt and examine the psychometric properties of the Chinese (Cantonese) version of the Upper Extremity Functional Index (C-UEFI) in people with chronic stroke.

Design

Cross-sectional study.

Settings

University-affiliated neurorehabilitation research laboratory.

Participants

The participants (N = 151) were people with chronic stroke (N = 101) and healthy controls (n = 50).

Main outcome measures

We assessed the C-UEFI, Fugl-Meyer Assessment for Upper Extremity (FMA-UE), Wolf Motor Function Test (WMFT), Six-Minute Walk Test (6MWT), Motor Activity Log (MAL), Activity-Specific Balance Confidence (ABC) scale, Lawton Instrumental Activities of Daily Living (IADL) scale, Survey of Activities and Fear of Falling in the Elderly (SAFFE), Stroke Impact Scale (SIS) and Community Integration Measure (CIM) as outcome measures.

Results

The C-UEFI items demonstrated good test-retest reliability (intraclass correlation coefficient [ICC]_{3, 1} = 0.872) and excellent internal consistency (Cronbach's α = 0.922). People with chronic stroke had poorer C-UEFI scores than the healthy controls. The overall C-UEFI mean score of 101 people with stroke was significantly correlated with the mean scores of the FMA-UE, WMFT, MAL, ABC scale, IADL scale, SAFFE, SIS and CIM and the distance covered in the 6MWT. The C-UEFI cut-off score to distinguish between people with chronic stroke and healthy older adults according to upper extremity function was 57.5 out of 59 (sensitivity: 88.1%; specificity: 84%). The C-UEFI had good content validity, with an acceptable fit to the two-factor structure model.

Conclusions

The C-UEFI is reliable and valid for assessing functional recovery of upper extremity activity in Chinese people with chronic stroke.

Comparing the use of mathematical calculation to a measuring wheel to determine distance walked in three different course configurations of the 6 minute Walk Test in healthy adults

INTRODUCTION

A recent clinical practice guideline set forth recommendations for the administration of the 6 Minute Walk Test, including course set-up and using mathematical calculation to obtain the distance walked. In clinical practice and research, however, deviations from these protocols exist.

PURPOSE

To assess for differences in total distance walked between use of mathematical calculation and a measuring wheel during three different course configurations of the 6 Minute Walk Test.

METHODS

Fifty healthy adults (18 males, 32 females) completed this study. The mean age was 37.04 (13.76) years ranging from 23 to 61 years. Each participant completed three course configurations of the 6 Minute Walk Test: a 12-meter straight walkway representing the Academy of Neurologic Physical Therapy Core Set of Outcome Measures Clinical Practice Guideline protocol, a 30-meter straight walkway, representing the American Thoracic Society's recommended protocol, and a 1.2-meter by 12-meter rectangular walkway, of which the Core Set of Outcome Measures Clinical Practice Guideline was derived. For mathematical calculation, the total number of laps counted, and this total number was multiplied by the distance of one lap with any partial lap added. Additionally, a research assistant followed behind each participant with a measuring wheel to capture distance walked.

RESULTS

For all configurations, there were statistically significant differences between mathematical calculation and a measuring wheel, with mathematical calculation producing significantly less total distance. Additionally, there were statistically significant differences between all course configurations, despite the method of measurement.

CONCLUSION

Adhering to 6 Minute Walk Test protocols, including the method of measuring the distance, is imperative to accurately interpret results and compare to existing data.Key messagesDespite recommendations for standardized administration of the 6 Minute Walk Test, deviations exist, including the method of which to obtain the total distance walked; either by use of mathematical calculation or a measuring wheel.In three different 6 minute walk test course configurations, including the American Thoracic Society's recommended protocol and the Academy of Neurologic Physical Therapy recommended protocol, the measuring wheel resulted in significantly larger distances than use of the mathematical calculation.Despite the measuring wheel able to account for the turns during the 6 Minute Walk Test, it is imperative for clinicians to utilize standardized procedures such as using mathematical calculation, in order to accurately track progress and compare to existing data, of which mathematical calculation was used to derive.

No association between body composition and walking outcomes in multiple sclerosis

BACKGROUND

One major concern of excess body weight is diminished physical function. The excess body weight associated with obesity can bring about challenges for physical function, particularly walking performance, among persons living with the consequences of a chronic, neurological disease. There is evidence that persons with multiple sclerosis (MS) have significantly reduced walking performance compared with controls; however, the relationship between body composition and walking outcomes has not been well-defined in persons with MS. To that end, the study examined the associations between body composition metrics and a comprehensive battery of walking outcomes in persons with MS recruited across a wide distribution of body mass index.

METHODS

Ambulatory participants with MS (n=64) underwent an assessment of neurological disability status using the Expanded Disability Status Scale (EDSS) and body composition metrics (i.e., percent body fat, fat mass, lean mass, bone mineral content and density) using dual-energy x-ray absorptiometry. Participants then completed the Timed 25-Foot Walk (T25FW), Timed Up and Go (TUG), 6-Minute Walk (6MW), and 12-Item Multiple Sclerosis Walking Scale (MSWS-12). We examined Spearman rank-order bivariate correlations among percent body fat, fat mass, lean mass, bone mineral content and density, T25FW, TUG, 6MW, MSWS-12, and EDSS.

RESULTS

Body composition metrics were not significantly associated with T25FW (rs=-.11, .12), TUG (rs=-.04, .11), 6MW (rs=-.01, .20), and MSWS-12 (rs=-.16, .03). Of note, body composition metrics were not correlated with disability status based on EDSS (rs=-.11, .03). Body composition metrics were not associated with walking outcomes even after controlling for EDSS.

CONCLUSION

Our data indicated that worse body composition profiles are not necessarily associated with worse walking performance, greater perception of MS-related walking impairment, or more severe disability status in MS. Future research may consider examining other health-related or disease outcomes of overweight or obesity in MS. Overall, our findings suggest that optimization of body composition may not be a target of interventions for improving walking outcomes, and future research might explore other factors that influence lower physical function in MS.

Functional Performance, Leg Muscle Strength, and Core Muscle Endurance in Multiple Sclerosis Patients With Mild Disability: A Cross-Sectional Study

This study aimed to investigate the relationship of sit-to-stand and walking performance with leg muscle strength and core muscle endurance in people with multiple sclerosis (PwMS) with mild disabilities. In this study, 49 PwMS (Expanded Disability Status Scale score = 1.59 ± 0.79) and 26 healthy controls were enrolled. The functional performances, including sit-to-stand and walking performances, were evaluated with the five-repetition sit-to-stand test, timed up and go test, and 6-min walking test. The PwMS finished significantly slower five-repetition sit-to-stand, timed up and go, and 6-min walking test than the healthy controls. In addition, the significant contributors were the weakest trunk lateral flexor endurance for five-repetition sit-to-stand; the Expanded Disability Status Scale score, and the weakest hip adductor muscle for timed up and go; the weakest hip extensor muscles strength for 6-min walking test. The functional performances in PwMS, even with mild disabilities, were lower compared with healthy controls. Decreases in both leg muscle strength and core muscle endurance are associated with lower functional performance in PwMS.

Restless legs syndrome severity associated with reduced physical function in adults with multiple sclerosis

BACKGROUND

Restless legs syndrome (RLS) is a sleep disorder that occurs in approximately 26 % of adults with multiple sclerosis (MS) and may be associated with reduced physical function.

RESEARCH QUESTION

The present study examined the relationship between RLS symptomology (i.e., overall severity, frequency, and occurrence) and physical function outcomes in adults with MS who had RLS.

METHODS

Participants (N = 22) with MS who had RLS came into the laboratory for a single session wherein a rater performed a brief neurological examination for scoring the Expanded Disability Status Scale (EDSS) and completed a demographics questionnaire, the International Restless Legs Syndrome Study Group Scale (IRLS), and the Restless Legs Syndrome Scale-6 (RLS-6) followed by the Short Physical Performance Battery (SPPB) and the Six-minute Walk Test (6 MW).

RESULTS

Bivariate Spearman's rho correlation analyses indicated total IRLS had a strong, negative association with total distance traveled during the 6 MW (ρ = -0.50) and a moderate association with SPPB scores (ρ = -0.43), but not EDSS scores (ρ = 0.28). RLS severity during the day while active had strong, negative associations with total distance traveled during the 6 MW (ρ = -0.61) and SPPB scores (ρ = -0.52), but not EDSS scores (ρ = 0.13).

SIGNIFICANCE

We observed associations between worse overall RLS severity and RLS severity during the day while active with reduced performance during the 6 MW and lower SPPB scores. The management of RLS may offer an opportunity for mitigating reductions in physical function in adults with MS who have RLS.

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.

Study Protocol: Strategies and Techniques for the Rehabilitation of Cognitive and Motor Deficits in Patients with Multiple Sclerosis

MS clinical features vary between patients. In approximately 60% of cases, cognitive deficits are associated with motor disabilities, with consequences on both walking and maintaining balance and cognitive efficiency. Multimodal programs are very infrequent for MS patients and cognitive rehabilitation is not provided by the Italian health system, which only favors access to motor rehabilitation. Dual-task studies showed how motor and cognitive skills are closely associated. Therefore, physiotherapy exercises may favor an indirect improvement in cognition. The aim of this study is to understand which rehabilitative approach may increase both cognitive and motor efficiency, avoiding the waste of time and resources. In this multi-site single-blind parallel controlled clinical trial, we will compare three rehabilitative approaches: cognitive training, motor training and combined cognitive–motor training. We also aim to evaluate: whether self-perception and objective improvement correspond; the impact of each rehabilitation program on patients’ QoL, mood and self-perception; and long-term effects. A total of 60 patients will be randomly assigned to one of the three treatments for two 45-min sessions/week for 12 weeks. All participants will undergo a complete cognitive, motor, clinical assessment together with mood, self-perception, and QoL questionnaires before, immediately after and 6 months after the training period.

Acute Thermoregulatory and Cardiovascular Response to Submaximal Exercise in People With Multiple Sclerosis

Background

Heat sensitivity occurs in a high percentage of people with multiple sclerosis (PwMS), in response to environmental or exercise-induced increase in body temperature. However, the kinetic and magnitude of adaptation of the internal load and of the core body temperature (CBT) to a submaximal continuous exercise has been poorly addressed in PwMS; this may be relevant for the brief exercise bouts usually occurring in normal daily life. The aim of this work was to evaluate whether multiple sclerosis influences the acute adaptation of the internal load, the CBT and the perceptual load in response to a constant submaximal work step.

Methods

CBT has been continuously monitored (0.5 Hz) by a validated wearable heat-flux sensor and electrocardiography was recorded (250 Hz) by a wearable device during a standard 6-minute walk test (6MWT) in 14 PwMS (EDSS, 4.7 ± 1.2; disease duration: 13.0 ± 10.2 years; m ± SD) and 14 age, sex and BMI-matched healthy subjects (HS). The rate of perceived exertion (RPE) of the lower limbs was assessed during the 6MWT by the Borg scale (6-20).

Results

As expected, PwMS walked a significantly shorter distance (361 ± 98 m) than the HS group (613 ± 62 m, p<0.001 vs PwMS). However, the kinetics of adaptation of CBT and the magnitude of CBT change from baseline did not differ between groups. Similarly, heart rate (HR) kinetics and HR change from baseline were comparable between groups during the 6MWT. Finally, lower limbs RPE gradually increased during the exercise test, but without significant differences between groups.

Conclusion

The internal load, the metabolic heat production, and the perceptive load due to a standard submaximal walking exercise seems to be preserved in PwMS, suggesting a comparable acute heat production and dissipation during exercise. Therefore, it is unlikely that the different distance achieved during the 6MWT may be caused by altered thermoregulatory responses to exercise. Rather, this appears to be a consequence of the known increased energy cost of locomotion in PwMS.

Implications of lower extremity muscle power and force for walking and fatigability in multiple sclerosis - An exploratory pilot-study

BACKGROUND

Limitations in physical function are common in Multiple Sclerosis (MS), yet it is neither clear how muscle power implicates physical function and walking-fatigability. This pilot-study aims to investigate (1) deficits in muscle power/force alongside walking in persons with MS; (2) associations between muscle power/force and physical functions and (3) the impact of prolonged walking in muscle power/force.

METHODS

30 relapse-remitting persons with MS and 28 healthy controls performed chair rise and plantar flexion on a force platform before and after 12-minutes of intermittent walking to measure lower extremity muscle power/force. GaitRite measured walking speed. The percentage change in distance walked was also calculated. Persons with MS were classified into subgroups according to walking-fatigability and mobility disability status (Patient Determined Disease Steps).

FINDINGS

Higher deficits in muscle power compared to force were observed in persons with MS vs. healthy controls particularly in persons with MS having higher disability. Muscle power and force were associated with walking capacity, mobility disability and subjective fatigue, but not with percentage change in distance walked. Persons with MS slowed down over the course of the 12-min intermittent walking, whereas decrements in walking speed and muscle power/force (derived from chair rise) were observed in persons with MS presenting walking-fatigability only.

INTERPRETATION

Muscle power and force are impaired in persons with MS and appear to be critical for physical function in MS. This exploratory pilot study further suggests that muscle power/force from chair rise could contributes to walking-fatigability which therefore offer future treatment targets.

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.

Outcome measures assisting treatment optimization in multiple sclerosis

Objective

To review instruments used to assess disease stability or progression in persons with multiple sclerosis (pwMS) that can guide clinicians in optimizing therapy.

Methods

A non-systematic review of scientific literature was undertaken to explore modalities of monitoring symptoms and the disease evolution of MS.

Results

Multiple outcome measures, or tools, have been developed for use in MS research as well as for the clinical management of pwMS. Beginning with the Expanded Disability Status Scale, introduced in 1983, clinicians and researchers have developed monitoring modalities to assess all aspects of MS and the neurological impairment it causes.

Conclusions

Much progress has been made in recent decades for the management of MS and for the evaluation of disease progression. New technology, such as wearable sensors, will provide new opportunities to better understand changes in function, dexterity, and cognition. Essential work over the decades since EDSS was introduced continues to improve our ability to treat this debilitating disease.

Sex-Based Differences in Oxygen Cost of Walking and Energy Equivalents in Minimally Disabled People with Multiple Sclerosis and Controls

Background: Elevated oxygen cost of walking and energy equivalents are reported for highly and moderately disabled people with multiple sclerosis (MS). However, less is known about minimally impaired individuals. Moreover, no sex-based data on the metabolic rates of people with MS are available. In this cross-sectional study, the metabolic rates and temporospatial parameters of gait during overground walking in minimally disabled people with MS versus matched controls were quantified and whether sex-based differences occur was examined.

Methods: Sixty-nine minimally impaired adults with MS (37, relapsing-remitting MS [RRMS]; 32, clinically isolated syndrome [CIS]) and 25 matched controls completed two 6-minute walking bouts at comfortable and fast speeds. The oxygen cost of walking, energy equivalents, and respiratory exchange ratio were recorded through breath-by-breath open-circuit spirometry. Gait analysis was performed via a portable electronic walkway.

Results: At comfortable but not at fast speed, men with RRMS showed higher oxygen cost of walking than men with CIS (+17.9%, P = .04) and male controls (+21.3%, P = .03). In the RRMS group, men showed higher oxygen cost of walking (+19.2%, P = .04) and energy equivalents (+19.2%, P = .02) than women. Elevated oxygen cost of walking and energy equivalents in men were paralleled by significantly larger base of support and step time asymmetry during walking.

Conclusions: Metabolic demands are elevated while walking in minimally disabled people with RRMS. Furthermore, higher energy demands occur in men, probably due to increased step symmetry and base of support. Clinicians are advised to follow energy expenditure metrics collected while walking because they can indicate a decrease in fitness, even in the early phase of MS.

Measuring Outdoor Walking Capacities Using Global Positioning System in People with Multiple Sclerosis: Clinical and Methodological Insights from an Exploratory Study

We aimed at showing how Global Positioning System (GPS) along with a previously validated speed processing methodology could be used to measure outdoor walking capacities in people with multiple sclerosis (MS). We also deal with methodological issues that may occur when conducting such measurements, and explore to what extent GPS-measured outdoor walking capacities (maximal walking distance [MWD_GPS] and usual walking speed) could be related to traditional functional outcomes (6-min total walking distance) in people with MS. Eighteen people with MS, with an Expanded Disability Status Scale score ≤6, completed a 6-min walking test and an outdoor walking session (60 min maximum) at usual pace during which participants were wearing a DG100 GPS receiver and could perform several walking bouts. Among the 12 participants with valid data (i.e., who correctly completed the outdoor session with no spurious GPS signals that could prevent the detection of the occurrence of a walking/stopping bout), the median (90% confidence interval, CI) outdoor walking speed was 2.52 km/h (2.17; 2.93). Ten participants (83% (56; 97)) had ≥1 stop during the session. Among these participants, the median of MWD_GPS was 410 m (226; 1350), and 40% (15; 70) did not reach their MWD_GPS during the first walking bout. Spearman correlations of MWD_GPS and walking speed with 6-min total walking distance were, respectively, 0.19 (-0.41; 0.95) and 0.66 (0.30; 1.00). Further work is required to provide guidance about GPS assessment in people with MS.

Evaluation of Prolonged Walking in Persons with Multiple Sclerosis: Reliability of the Spatio-Temporal Walking Variables during the 6-Minute Walk Test

Background: Walking disorders represent the most disabling condition in persons with Multiple Sclerosis (PwMS). Several studies showed good reliability of the 6-min walk test (6MWT) (i.e., especially distance traveled), but little is known about the reliability of the Spatio-temporal (ST) variables in the 6MWT. Objective: To evaluate the test-retest reliability of ST variables and perceived exertion during the 6MWT in PwMS and comparable healthy persons. Methods: We explored three 1-min intervals (initial: 0′–1′, middle: 2′30″–3′30″, end: 5′–6′) of the 6MWT. Six ST variables and perceived exertion were measured (respectively, using the GAITRite system and the Borg Scale). These measurements were performed twice, 1 week apart. The test-retest effects were assessed using the intraclass correlation coefficient (ICC) or the weighted kappa. Results: Forty-five PwMS and 24 healthy persons were included. The test-retest reliability of ST variables values was good-to-excellent for PwMS (ICC range: 0.858–0.919) and moderate-to-excellent for healthy persons (ICC range: 0.569–0.946). The test-retest reliability values of perceived exertion were fair for PwMS (weighted kappa range: 0.279–0.376) and substantial for healthy persons (weighted kappa range: 0.734–0.788). Conclusion: The measurement of ST variables during these 6MWT intervals is reliable and applicable in clinical practice and research to adapt rehabilitation care in PwMS.

The impact of physical functions on depressive symptoms in people with multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is an immune-mediated disease that affects the central nervous system. The impact of MS transcends physical functions and extends to psychological impairment. Approximately 50% of people with MS develop depressive symptoms during their lifetime and depressive symptoms may predict impairment of physical functions. However, prediction of depressive symptoms based on objective measures of physical functions is still necessary.

OBJECTIVE

To compare physical functions between people with MS presenting depressive symptoms or not and to identify predictors of depressive symptoms using objective measures of physical functions.

METHODS

Cross-sectional study including 26 people with MS. Anxiety and/or depressive symptoms were assessed by the Beck Depression Inventory-II (BDI-II) and by the Hospital Anxiety and Depression Scale (HADS). Outcomes of physical functions included: the Nnnine-hole Ppeg Ttest (NHPT), knee muscle strength, balance control, the Timed Up and Go Test (TUG), and the 6-minute walk test (6MWT). Perceived exertion was measured using the Borg scale.

RESULTS

The frequency of depressive symptoms was 42% in people with MS. Balance control during a more challenging task was impaired in people with MS who presented depressive symptoms. Balance could explain 21-24% of the variance in depressive symptoms. 6MWT and TUG presented a trend of significance explaining 16% of the variance in the BDI-II score.

CONCLUSIONS

Impairment in physical functions consists in a potential predictor of depressive symptoms in people with MS. Exercise interventions aiming at the improvement of physical functions, together with the treatment of depressive symptoms and conventional medical treatment, are suggested.

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

OBJECTIVES

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

DATA SOURCES

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

STUDY SELECTION

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

DATA EXTRACTION

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

DATA SYNTHESIS

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

CONCLUSIONS

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

Cognitive Processing Speed Impairment Does Not Influence the Construct Validity of Six-Spot Step Test Performance in People With Multiple Sclerosis

OBJECTIVE

There is evidence supporting the construct validity of Six-Spot Step Test (SSST) performance as a functional mobility measure in people with multiple sclerosis (MS); however, it is unknown if cognitive processing speed impairment confounds the construct validity of SSST performance in MS, as this test seemingly requires intact cognitive processing. The objective of this study was to examine the influence of cognitive processing speed impairment on the construct validity and precision of SSST performance as a functional mobility measure in MS.

METHODS

Participants (N = 213) completed the SSST, timed 25-foot walk, 6-Minute Walk Test, Timed "Up and Go" Test, Multiple Sclerosis Walking Scale-12, device-measured steps per day, and Late-Life Function and Disability Inventory, Patient-Determined Disease Steps, and the Symbol-Digit Modalities Test as a cognitive processing speed measure. The overall sample was divided into subsamples with (n = 75) and without (n = 138) cognitive processing speed impairment based on normative Symbol-Digit Modalities Test data. Correlations between SSST performance with other mobility outcomes in the overall sample and cognitive processing speed impairment subsamples were examined and compared. SSST performance was compared relative to other mobility measures for differentiating MS walking function levels in people with and without cognitive processing speed impairment.

RESULTS

SSST performance was significantly and strongly correlated with most mobility outcomes in the overall sample and cognitive processing speed impairment subsamples. The magnitudes of correlations between SSST performance with most mobility outcomes were not statistically different among subsamples. Cognitive processing speed impairment did not diminish the relative precision of SSST performance for differentiating walking function levels.

CONCLUSION

The presence of cognitive processing speed impairment is not a source of invalidity or imprecision when interpreting SSST performance as a functional mobility measure among people with MS.

IMPACT

The SSST is a high-quality endpoint for inclusion in interventions targeting mobility in MS, regardless of cognitive processing speed status. This information is critical for rehabilitation research and clinical practice given that mobility and cognitive impairment are highly prevalent, co-occurring, and disabling in MS.

Rehabilitation Improves Mitochondrial Energetics in Progressive Multiple Sclerosis: The Significant Role of Robot-Assisted Gait Training and of the Personalized Intensity

Abnormal levels of pyruvate and lactate were reported in multiple sclerosis (MS). We studied the response of markers of mitochondrial function to rehabilitation in relation to type, intensity and endurance performance in severely disabled MS patients. Forty-six progressive MS patients were randomized to receive 12 walking sessions of robot-assisted gait training (RAGT, n = 23) or conventional overground therapy (CT, n = 23). Ten healthy subjects were also studied. Blood samples were collected to determine lactate, pyruvate, and glutathione levels and lactate/pyruvate ratio pre–post rehabilitation. In vivo muscle metabolism and endurance walking capacity were assessed by resting muscle oxygen consumption (rmVO₂) using near-infrared spectroscopy and by six-minute walking distance (6MWD), respectively. The levels of mitochondrial biomarkers and rmVO₂, altered at baseline with respect to healthy subjects, improved after rehabilitation in the whole population. In the two groups, an enhanced response was observed after RAGT compared to CT for lactate (p = 0.012), glutathione (<0.001), lactate/pyruvate ratio (p = 0.08) and rmVO₂ (p = 0.07). Metabolic biomarkers and 6MWD improvements were exclusively correlated with a training speed markedly below individual gait speed. In severely disabled MS patients, rehabilitation rebalanced altered serum metabolic and muscle parameters, with RAGT being more effective than CT. A determinable slow training speed was associated with better metabolic and functional recovery. Trial Registration: ClinicalTrials.gov NCT02421731.

Reliability of the six-minute walk test in individuals with stroke: systematic review and meta-analysis

PURPOSE

The six-minute walking test (6MWT) is a simple and widely used measure of functional capacity. The aim of this systematic review is to summarize findings on reliability of 6MWT in subjects who have had a stroke.

METHODS

Two independent investigators conducted an extensive search in multidisciplinary electronic databases from inception to August 2019, and selected complete original studies on the reliability of the 6MWT used to assess individuals with stroke. Two reviewers independently extracted data and evaluated methodological quality. Outcome for meta-analysis was reliability, measured by intraclass correlation coefficient (ICC). In addition, standard error of measurement (SEM) and minimal detectable change (MDC) were recorded.

RESULTS

Of the 241 potentially relevant articles screened, 6 met inclusion criteria and 5 of them were included in meta-analysis. Combined correlation coefficient of .98 (confidence interval .98-.99) was found for test-retest reliability. Only one study investigated inter-rater and intra-rater reliability. SEM and MDC values were rarely reported.

CONCLUSIONS

The 6MWT has high test-retest reliability, when used to assess individuals with stroke. Other types of reliability and SEM and MDC need further investigations in populations with a stroke.

Nordic walking for people with relapsing-remittent multiple sclerosis: A case series study

BACKGROUND

Patients with multiple sclerosis (MS) show fatigue, impaired gait and decreased functional mobility, which lead to a low quality of life (QoL). Low-cost and easy to perform exercise modalities having a positive impact on the aforementioned symptoms are needed. The performance of Nordic Walking (NW) could be a useful rehabilitation strategy but, to our knowledge, no study has been published in this regard as yet. This case series study aims at providing information regarding the usefulness and impact of a three-month NW program on self-perceived fatigue, functional mobility, physical fitness and QoL on a group of people with mild relapsing-remitting MS.

METHODS

A case series study with multiple assessments was performed. Three data collection points at 1-week intervals for three weeks were done at baseline. The intervention consisted of a 12-weeks NW program with a total of four measurement occasions, one every three weeks. The Fatigue Severity Scale (FSS), the Timed up and Go test (TUG), the 6-Minute Walk test (6MWT) and the Multiple Sclerosis Impact Scale (MSIS-29), were used to assess the outcomes of the program on the participants' self-perceived fatigue, functional mobility, physical fitness and QoL, respectively.

RESULTS

Of the 14 participants who volunteered for the study, five completed at least 80% of the planned sessions and were included in the final analysis. The intervention did not have a clinical significant impact on the participants' fatigue while its impact on their QoL showed mixed results. Positive trends were found for all the participants in their functional mobility and physical fitness. Regarding functional mobility, clinically important changes were observed in three participants. None of the observed changes in physical fitness achieved clinical significance.

CONCLUSION

A 12-week Nordic walking program did not appear to be particularly feasible and had little impact on the functional levels on a group of people with mild relapsing-remitting MS. Given that beneficial effects were seen in some participants, and taken into account the low adherence rate observed, future studies should explore the feasibility of NW programs performed under different environmental conditions (i.e. outdoors) and including motivational strategies aimed at increasing participation.

Clinical assessment, management, and rehabilitation of walking impairment in MS: an expert review

INTRODUCTION

One of the most common and life-altering consequences of Multiple Sclerosis (MS) is walking impairment. The distance, speed, and Gait pattern functions are components of the International Classification of Functioning, Disability, and Health (ICF) and are also predictors of dependency in terms of daily living activities in patients with MS (pwMS).

AREAS COVERED

This article provides an overview of walking impairment in pwMS, with focus on the assessment of gait and the rehabilitation approaches.

EXPERT OPINION

The authors recommend that pwMS undergo gait assessment integrating the ICF perspective using validated clinical outcome measures that cover spatiotemporal gait parameters. Moreover, assessment of walking speed with short walking capacity tests such as the timed 25-foot walk (T25FW) or the 10-m walk test (10 MWT) and tests for walking distance with middle distance tests such as the 2-min walk test (2MWT) and the 6-min walk test (6MWT). This review further highlights strategies that may restore walking function including pharmacological symptomatic treatment and non-pharmacological rehabilitation approaches such as exercise and task-specific training providing an appraisal of mobility targeted therapies to be considered when planning multidisciplinary comprehensive-care of pwMS. Finally, new and novel strategies such as motor imagery and rhythmic auditory stimulation have been developed to improve walking speed and distance in pwMS.

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 association between gait variability with the energy cost of walking depends on the fall status in people with multiple sclerosis without mobility aids

BACKGROUND

Falls, gait variability and increased energy cost of walking are common in people with multiple sclerosis (PwMS). However, no studies have as yet examined this triple association in PwMS or in other neurological populations.

RESEARCH QUESTION

Does a relationship exist between gait variability, falls and the energy cost of gait in PwMS?

METHODS

This cross sectional study included 88 PwMS (50 women), mean age 39.8 (S.D = 13.0) and mean disease duration of 6.2 (SD = 8.2) years since diagnosis. Energy expenditure during walking was collected via a portable metabolic device (COSMED K5, COSMED Srl, Roma, Italy). Gait variability was measured by an electronic walkway (GAITRite™). Participants were divided into groups based on fall history (fallers and non-fallers). Differences between groups in terms of energy expenditure measures and gait variability metrics were determined by the analysis of variance test. The relationship between gait variability and energy cost of walking was examined by the Pearson's correlation coefficient test.

RESULTS

Thirty-three PwMS were classified as fallers and 55 as non-fallers. Non-significant differences between groups were observed in the energy expenditure measures, including cost of walking. Fallers demonstrated higher step length variability compared with non-fallers (4.58 (S.D. = 2.42 vs. 3.40 (S.D. = 1.40); p-value = 0.005). According to the Pearson's correlation coefficient analysis, a significant relationship was found between step length variability and energy cost of walking in the non-fallers group (Rho = 0.372, P-value = 0.006) and the total group (Rho = 0.296, p-value = 0.005), but not in those PwMS with a history of falls.

SIGNIFICANCE

We demonstrated a significant relationship between increased gait variability and energy expenditure while walking only in MS patients without a history of falls. This is important as there is evidence of the clinical relevance of increased gait variability, poor fitness level and high risk of falling in the MS population.