Six-minute walk test for persons with mild or moderate disability from multiple sclerosis: performance and explanatory factors

The relationship between cognitive function and functional capacity, and cognitive reserve and reaction time in patients with multiple sclerosis

BACKGROUND

 Cognitive dysfunction is frequently seen in multiple sclerosis (MS). However, there are conflicting findings regarding the factors it is associated with.

OBJECTIVE

 To investigate the relationship between aerobic capacity, strength, disability, depression, fatigue, and cognitive reserve and function.

METHODS

 The mobile applications Trail Making Test (TMT A-B), Digit Span Test (DST), Visuospatial Memory Test (VSMT), and Tap Fast were used in the cognitive function evaluation. Functional performance was assessed with the 6-minute walk test (6MWT), 5-Time Sit-to-Sand (5STS) test, and grip strength. Cognitive Reserve Index (CRI), Beck Depression Inventory, Fatigue Severity Scale (FSS), and Nottingham Health Profile were also used.

RESULTS

 A significant difference was found between the MS and control groups only in the 6MWT, STS-5, grip strength, TMT, VSMT, and Tap Fast. Good correlation was found between the TMT-A and 6MWT and physical mobility. A fair correlation was shown between grip strength, energy, and pain status. A good correlation was found between TMT-B and 6MWT, and a fair relationship with disability, cognitive reserve, and pain. Good correlation was observed between the DST and 6MWT, left grip strength, pain, and energy status; fair correlations were found between right grip strength, cognitive reserve, and physical mobility. Good correlation was found between the VSMT and energy. A fair relationship between disability, cognitive reserve, and pain was demonstrated. Good correlation was observed between the Tap Fast score and disability, 5STS, FSS, energy, and physical mobility. A fair relationship was found between pain and social isolation.

CONCLUSION

 It has been shown that cognitive performance in MS is related to disability, functional performance, cognitive reserve, fatigue, and general health.

TRIAL REGISTRATION

 NCT06084182.

Exercising with a robotic exoskeleton can improve memory and gait in people with Parkinson's disease by facilitating progressive exercise intensity

People with Parkinson's disease (PwPD) can benefit from progressive high-intensity exercise facilitated with a lower-extremity exoskeleton, but the mechanisms explaining these benefits are unknown. We explored the relationship between exercise intensity progression and memory and gait outcomes in PwPD who performed 8 weeks (2 × per week) of progressive exercise with and without a lower-extremity powered exoskeleton, as the planned exploratory endpoint analysis of an open-label, parallel, pilot randomized controlled trial. Adults 50-85 years old with a confirmed diagnosis of PD participated. Twenty-seven participants randomized to exercise with (Exo = 13) or without (Nxo = 14) the exoskeleton were included in this exploratory endpoint analysis. Detailed exercise logs were kept and actigraphy was used to measure activity count*min-1 (ACPM) during all exercise sessions. Only the Exo group were able to progressively increase their ACPM over the entire 8-week intervention, whereas the Nxo group plateaued after 4 weeks. Exercise intensity progression correlated with change in the memory sub-scale of the SCOPA-COG and change in gait endurance from the 6MWT, consistent with the prevailing hypotheses linking high-intensity interval exercise to improved muscle and brain function via angiogenic and neurotrophic mechanisms. Facilitating high-intensity exercise with advanced rehabilitation technology is warranted for improving memory and gait endurance in PwPD.Registration: ClinicalTrials.gov, NCT03583879 (7/10/2018).

Reliability and validity of the glittre activities of daily living test in fully ambulatory multiple sclerosis patients

BACKGROUND

Evaluation of activities of daily living (ADL) and functional exercise capacity in patients with multiple sclerosis (pwMS) is crucial in demonstrating the effectiveness of interventions.

AIMS

To investigate the reliability and validity of the Glittre ADL Test in pwMS.

METHODS

Twenty-five pwMS and 26 healthy adults were included in this methodological study. The Glittre ADL Test was applied. Six-Minute Walk Test (6MWT) and Nottingham Extended Activities of Daily Living Index (NEADL) were applied for concurrent validity. Expanded Disability Status Scale (EDSS), Fatigue Severity Scale (FSS), Mini Balance Evaluation Systems Test (Mini BESTest), Multiple Sclerosis Quality of Life Scale-54 (MSQoL-54), and Five Times Sit-to-Stand Test (5 STST) were applied for construct validity. The Glittre ADL Test was repeated after 3-6 days for test-retest reliability.

RESULTS

The test-retest reliability of the Glittre ADL Test was excellent (ICC = 0.941). There was strong correlation of the Glittre ADL Test with 6MWT (rho = - 0.710, p < 0.001), NEADL (rho = - 0.841, p < 0.001), EDSS, (rho = 0.836, p = < 0.001), Mini BESTest (rho = 0.792, p < 0.001), and 5 STST scores (rho = 0.720, p < 0.001). There was a moderate correlation between the Glittre ADL Test and the physical health sub-item score of the MSQoL-54 (rho = - 0.591, p = 0.002). No correlation was found between the Glittre ADL Test and FSS (rho = 0.348, p = 0.096). There was a difference in the Glittre ADL Test results between the pwMS and the healthy adults (p = 0.001).

CONCLUSIONS

The Glittre ADL Test has excellent reliability and strong construct and criterion validity for assessing functional exercise capacity and ADL in fully ambulatory pwMS.

TRIAL REGISTRATION

TRN: NCT04182269.

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.

Effect of Nordic Walking Training on Walking Capacity and Quality of Life for People With Multiple Sclerosis

BACKGROUND

Although there is emerging evidence that aerobic training improves walking capacity in persons with multiple sclerosis (MS), data are limited about the potential benefits of Nordic walking (NW) for this population. This study evaluates the effectiveness of outdoor NW training on walking capacity and related quality of life for people with MS compared with cycloergometer and treadmill aerobic training.

METHODS

A single-blinded (evaluator), randomized, 2-arm clinical trial was designed.

RESULTS

A total of 57 patients with MS (38 women and 19 men; mean ± SD age, 51.98 ± 9.93 years; mean ± SD disease duration, 14.75 ± 8.52 years) were included. Both therapeutic modalities improved walking distance as measured by the 6-Minute Walk Test after the training period. The NW group showed significant improvement on the physical and emotional subscales of the Multiple Sclerosis Quality of Life-54 compared with the cycloergometer and treadmill group, which showed improvement only on the physical subscale.

CONCLUSIONS

Both training modalities proved to be of equal benefit in improving the walking capacity of people with MS, but outdoor NW training also seems to have a beneficial effect on the emotional component of health-related quality of life.

Is there a relationship between respiratory function and trunk control and functional mobility in patients with relapsing-remitting multiple sclerosis?

OBJECTIVE

Multiple sclerosis (MS) causes impairment of respiratory function, trunk control, and functional mobility. The purpose of this study was to investigate the relationship between functional mobility and respiratory function and trunk control in MS patients and to compare the findings with those in healthy individuals.

METHODS

Thirty MS patients and 30 healthy subjects were included in this case-control study. All participants were evaluated with a pulmonary function test, maximal inspiratory and expiratory pressure (MIP, MEP), core stability tests, a lumbopelvic stability test (LST), a 2-minute walk test (2MWT), and the Timed Up and Go test (TUG). The disability level of the MS patients was assessed with the Expanded Disability Status Scale (EDSS).

RESULTS

Respiratory function, respiratory muscle strength, trunk control, and functional mobility were lower in the MS patients than in the controls (p < 0.05). TUG values had a significant negative correlation and the 2MWT values had a significant positive correlation with MEP, core stability tests, and the LST (p < 0.05). Of the variance in the 2MWT distance, 69% was explained by the LST, EDSS, and MEP; of the variance in TUG time, 40% was explained by the EDSS and MEP (p < 0.05).

CONCLUSIONS

To preserve and develop functional mobility in MS patients, approaches to increase respiratory function and trunk control should be included in rehabilitation programs.

CLINICALTRIALS.GOV REGISTRATION NUMBER

NCT03826095.

Reliability and validity of the incremental shuttle walk test in patients with fully ambulatory multiple sclerosis

BACKGROUND

Functional exercise capacity evaluation is crucial to monitor treatment effects and disease progression in people with multiple sclerosis (pwMS). Compared to other tests, the incremental shuttle walking test (ISWT), which more accurately reflects cardiovascular responses, may be more useful for assessing exercise capacity. The aim of the study is to investigate the reliability and validity of the ISWT.

METHODS

Thirty-six pwMS with an Expanded Disability Status Scale (EDSS) score<4.5 between the ages of 25 and 65 were included in the study. The subjects underwent practice (ISWT-p) before undergoing the test-retest protocol in order to rule out the ISWT learning effect (ISWT-1 - ISWT-2). ISWT-1 and ISWT-2 were administered with a 3-7 day interval for test-retest reliability. Six-minutes walking test (6MWT) were applied for concurrent validity. The EDSS, pulmonary function tests, Fatigue Impact Scale (FIS), respiratory muscle strength [maximum inspiratory and expiratory pressure (MIP-MEP)] measurements were made for convergent validity.

RESULTS

ISWT was found to have excellent test-retest reliability with an ICC value of 0.97. The area under the curve value was 0.904 indicating that ISWT has a good performance for predicting disease severity. The moderate correlation between ISWT and 6MWT (rho: 0.68, p<0,001) proved concurrent validity. It was also moderately correlated with EDSS, MEP (rho: -0.58 and 0.47 respectively), weakly correlated with MIP and FIS (rho:0.37 and -0.36, respectively) while not correlated with pulmonary function tests.

CONCLUSION

The ISWT had excellent test-retest reliability, acceptable criterion and construct validity in ambulatory MS patients.

Six-Minute Walk as a Measure of Walking Capacity and Endurance in Patients With Pediatric-Onset Multiple Sclerosis

BACKGROUND AND OBJECTIVES

Despite low levels of disability, youth with pediatric-onset multiple sclerosis (POMS) engage in less physical activity compared with peers. The contribution of walking capacity, endurance, behavior, and MS comorbidities remains relatively undefined and may provide valuable insights into the limitations toward physical activity in youth with MS. The primary objective of this study was to investigate differences in walking capacity, endurance, and real-world behaviors of daily activity between youth with POMS and controls.

METHODS

Youth diagnosed with MS prior to 18 years and aged 21 years or younger were recruited in addition to healthy controls. Participants completed questionnaires to quantify fatigue, depression, and physical activity levels and the timed 2- and 6-minute walk (6MW) as an assessment of walking capacity and endurance. Participants completed questionnaires to quantify fatigue, depression, and physical activity levels. Participants also completed the timed 2- and 6-minute walk (6MW) as an assessment of walking capacity and endurance and were sent home with a waist-worn accelerometer to assess real-world walking behavior.

RESULTS

Forty-five patients with POMS and 85 control participants were enrolled. The POMS cohort had a mean age of 16.9 ± 2.7 years, with a mean disease duration of 2.8 ± 2.6 years. A greater proportion of the POMS cohort was overweight/obese compared with controls (75% vs 33%). Participants with MS walked a significantly shorter distance in 6 minutes compared with controls (1,848 feet vs 2,134 feet, p < 0.0001) and, unlike controls, were unable to accelerate to their peak speed at the end of the 6MW. Body mass index category and MS disease significantly affected 6MW performance. Using continuous accelerometry, participants with MS spent less time in moderate-to-vigorous physical activity compared with controls (20.4 vs 35.4 min/d, p = 0.0003). The POMS cohort reported significantly higher levels of depression and fatigue but self-reported similar levels of daily physical activity as controls.

DISCUSSION

Youth with POMS exhibit slower 6MW performance and less daily engagement in moderate-to-vigorous physical activity, suggesting limitations in functional walking capacity, endurance, and daily activity behavior. Limitations in walking endurance and capacity are most prominent in those youth who are overweight/obese and living with MS.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that, compared with healthy controls, patients with POMS walk shorter distances on the 6MW test, are less able to accelerate to peak speed at the end of the test, and are less physically active.

Using gait robotics to improve symptoms of Parkinson's disease: an open-label, pilot randomized controlled trial

BACKGROUND

People with Parkinson's Disease (PD) have difficulty participating in exercise.

AIM

The primary objective of this pilot randomized controlled trial (RCT) was to determine if 8 weeks (2x per week) of bilateral exoskeleton (Exo) exercise results in positive changes in cognition and participation in adults with PD compared to exercising without an exoskeleton (Nxo) or wait-list control (Con).

DESIGN

Open-label, parallel, pilot randomized controlled trial.

SETTING

Neurorehabilitation clinic in a large urban center.

POPULATION

Adults 50-85 years old with a confirmed diagnosis of PD.

METHODS

Eight weeks of twice-weekly combined aerobic, strength and mobility exercise or wait-list control. Participants were randomly assigned to exercise with no exoskeleton (Nxo), exercise with the exoskeleton (Exo), or waitlist control (Con). Primary endpoints were change in cognitive function (SCOPA-COG) and mood. Secondary endpoints were change in gait speed, six-minute walk test (6MWT), freezing of gait, balance, and PD-specific health and quality of life outcomes. Safety endpoint was analysis of adverse events (AE).

RESULTS

Forty participated in the trial (Exo, N.=13; Nxo, N.=14; Con, N.=13). Significant improvement in the Memory & Learning domain of the SCOPA-COG (P=0.014) and 6MWT (P=0.008) were detected for the Exo group compared to the Nxo and/or Con group. No other statistically significant between-groups effects were found. There were no serious or unanticipated AE.

CONCLUSIONS

Functional exercise with a low-profile overground exoskeleton showed promising results for improving memory and gait endurance in people with PD across HY stages I-IV.

CLINICAL REHABILITATION IMPACT

Exoskeletons can improve participation in high-intensity exercise.

The optimal cutoff score of the 2-min step test and its association with physical fitness in type 2 diabetes mellitus

This study was carried out to evaluate sensitivity, specificity, and test cutoff score to predict cardiorespiratory fitness by using the 2-min step test (2MST) in patients with type 2 diabetes mellites (DM). The association of the 2MST and physical fitness tests including a 6-min walk test (6MWT), a 5 time sit-to-stand test (FTSST), and leg strength in the form of a leg performance test were also investigated. This study was cross-sectional and conducted in 100 type 2 DM patients. Patients were screened through health questionnaires, medical illness, general characteristics, and physical fitness tests; 2MST, 6MWT, FTSST, and leg strength. Blood was collected for assessment of fasting blood sugar and lipid profiles. The number of steps in the 2MST was positively correlated with the distance of the 6MWT (r=0.6995, P<0.0001) and leg strength (r=0.4292, P<0.0001). 2MST was negatively correlated with time to perform the FTSST (r=−0.405, P<0.0001). Moreover, this study established the optimal cutoff score of the 2MST at ≤61 steps with 92.24% sensitivity, and 81.36% specificity to predict cardiorespiratory fitness in type 2 DM patients. Our findings indicate that the 2MST may be used as a predictor for walking capacity, leg strength, and ability to change position from sitting to standing in type 2 DM. In addition, this result may imply that patients with type 2 DM performing the 2MST at less than 61 steps was significantly associated with decreased cardiorespiratory fitness.

Efficacy of Transcranial Direct Current Stimulation (tDCS) on Balance and Gait in Multiple Sclerosis Patients: A Machine Learning Approach

Transcranial direct current stimulation (tDCS) has emerged as an appealing rehabilitative approach to improve brain function, with promising data on gait and balance in people with multiple sclerosis (MS). However, single variable weights have not yet been adequately assessed. Hence, the aim of this pilot randomized controlled trial was to evaluate the tDCS effects on balance and gait in patients with MS through a machine learning approach. In this pilot randomized controlled trial (RCT), we included people with relapsing−remitting MS and an Expanded Disability Status Scale >1 and <5 that were randomly allocated to two groups—a study group, undergoing a 10-session anodal motor cortex tDCS, and a control group, undergoing a sham treatment. Both groups underwent a specific balance and gait rehabilitative program. We assessed as outcome measures the Berg Balance Scale (BBS), Fall Risk Index and timed up-and-go and 6-min-walking tests at baseline (T0), the end of intervention (T1) and 4 (T2) and 6 weeks after the intervention (T3) with an inertial motion unit. At each time point, we performed a multiple factor analysis through a machine learning approach to allow the analysis of the influence of the balance and gait variables, grouping the participants based on the results. Seventeen MS patients (aged 40.6 ± 14.4 years), 9 in the study group and 8 in the sham group, were included. We reported a significant repeated measures difference between groups for distances covered (6MWT (meters), p < 0.03). At T1, we showed a significant increase in distance (m) with a mean difference (MD) of 37.0 [−59.0, 17.0] (p = 0.003), and in BBS with a MD of 2.0 [−4.0, 3.0] (p = 0.03). At T2, these improvements did not seem to be significantly maintained; however, considering the machine learning analysis, the Silhouette Index of 0.34, with a low cluster overlap trend, confirmed the possible short-term effects (T2), even at 6 weeks. Therefore, this pilot RCT showed that tDCS may provide non-sustained improvements in gait and balance in MS patients. In this scenario, machine learning could suggest evidence of prolonged beneficial effects.

Changes in trunk and head acceleration during the 6-minute walk test and its relation to falls risk for adults with multiple sclerosis

For persons with multiple sclerosis (MS), the general decline in neuromuscular function underlies diminished balance, impaired gait and consequently, increased risk of falling. During gait, optimal control of head motion is an important feature which is achieved partly through control of the trunk-neck region to dampen gait-related oscillations. The primary aim of this study was to examine the effect performing a 6-minute walk test (6MWT) has on head, neck and trunk accelerations in individuals with MS. This was addressed using a repeated measures generalized linear model. We were also interested in assessing whether the 6MWT has an impact on a person's falls risk and specific physiological measures related to falls. Finally the relation between the amplitude (i.e., mean RMS) of head and trunk accelerations and falls risk was examined using linear regression. The main results were that over the course of the 6MWT, individuals progressively slowed down coupled with a concurrent increase in gait-related upper body accelerations (p's > 0.05). Despite the increased acceleration, no significant changes in attenuation from the trunk to the head were observed, indicating that persons were able to maintain an optimal level of control over these oscillations. Performing the 6MWT also had a negative impact on posture, with falls risk significantly increasing following this test (p > 0.05). Interestingly, the overall falls risk values were strongly linked with vertical accelerations about the trunk and head, but not average walking speed during the 6MWT. Overall, performing the 6MWT leads to changes in walking speed, upper body acceleration patterns and increases in overall falls risk.

Urinary incontinence and impaired physical function are associated with expiratory muscle weakness in patients with multiple sclerosis

PURPOSE

Patients with multiple sclerosis (MS) with respiratory muscle weakness could have physical function impairments, given the functional/biomechanical link of the trunk stabilising system. Thus, clinicians could employ new treatment strategies targeting respiratory muscles to improve their physical function. This study pretends to evaluate the relationship between respiratory muscle strength, pulmonary function and pelvic floor function, and also to correlate these variables with physical function (gait function, disability and quality of life) in patients with MS.

METHODS

41 patients participated in this descriptive cross-sectional study. Respiratory muscle strength [maximal respiratory pressures (MIP/MEP)], pulmonary function (forced spirometry), pelvic floor function [urinary incontinence (UI)], physical function [Timed Up & Go (TUG) test, Barthel index and health status questionnaire (SF-12)] were evaluated.

RESULTS

Respiratory muscle strength and pulmonary function were moderately related to UI (MIP: rho = -0.312; MEP: rho = -0.559). MEP was moderately related to physical function (TUG: rho = -0.508; Barthel index: rho = 0.418). Patients with and without expiratory muscle weakness showed differences in UI, pulmonary and physical function.

CONCLUSION

Patients with MS with greater deterioration in pulmonary function and respiratory muscle strength, especially expiratory muscles, showed greater deterioration in UI and physical function. Expiratory muscle weakness had a negative impact on urinary, physical and pulmonary function.Implications for rehabilitationPulmonary function is associated with urinary incontinence and gait functionality in patients with multiple sclerosis (MS).Expiratory muscle weakness is associated with impaired urinary and physical function in patients with MS.The inclusion of respiratory muscle training to the rehabilitation programs of patients with MS could improve their pelvic floor disorders and physical function.

Inter-Session Reliability of Functional Near-Infrared Spectroscopy at the Prefrontal Cortex While Walking in Multiple Sclerosis

Many established technologies are limited in analyzing the executive functions in motion, especially while walking. Functional near-infrared spectroscopy (fNIRS) fills this gap. The aim of the study is to investigate the inter-session reliability (ISR) of fNIRS-derived parameters at the prefrontal cortex while walking in people with multiple sclerosis (MS) and healthy control (HC) individuals. Twenty people with MS/HC individuals walked a 12 m track back and forth over 6 min. The primary outcomes were the absolute and relative reliability of the mean, slope coefficient (SC), and area under the curve (A) of the oxy-/deoxyhemoglobin concentrations (HbO/HbR) in the Brodmann areas (BA) 9/46/10. The SC and the A of HbO exhibited a fair ISR in BA10 in people with MS. For the mean and A of the HbR, almost all areas observed revealed a fair ISR. Overall, the ISR was better for HbR than HbO. A fair to excellent ISR was found for most BA of the prefrontal cortex in HC individuals. In total, the ISR of the analyzed fNIRS-derived parameters was limited. To improve the ISR, confounders such as fatigue and mind wandering should be minimized. When reporting the ISR, the focus should be on the mean/A rather than SC.

Explanatory factors of balance confidence in persons with multiple sclerosis: Beyond the physical functions

BACKGROUND

Balance confidence is considered a psychological element of falls and balance-demanding activities. The relationship of balance confidence with physical factors has been investigated; however, psychosocial correlates are not well known. The aim was to investigate the relationship between balance confidence and physical and psychosocial factors and to reveal the determinants of balance confidence in persons with MS (pwMS).

METHODS

A total of 445 pwMS were enrolled in the study. Balance confidence was assessed with the Activities-Specific Balance Confidence (ABC) Scale. Psychosocial-based measures included the Modified Fatigue Impact Scale (MFIS), Epworth Sleepiness Scale (ESS), Beck Depression Scale (BDI), and Symbol Digit Modalities Test (SDMT). The Godin Leisure-Time Exercise Questionnaire (GLTEQ), Timed 25-Foot Walk (T25FW), Six-Minute Walk Test (6MWT), and Single Leg Stance Test (SLS) were used to assess physical functions.

RESULTS

There was a significant correlation between the ABC score and all physical and psychosocial measures (p<0.05). Hierarchical linear regression analyses indicated that psychosocial factors were significantly associated with ABC accounting for 41% of the variance. The addition of physical variables explained an additional 35% of variance over psychosocial variables. The MFIS, SDMT, BDI, T25FW, 6MWT, and SLS were significantly predictive of the ABC.

CONCLUSION

This study emphasizes the importance of considering both physical and psychosocial factors for understanding balance confidence in pwMS. Besides, intervention strategies for enhancing balance confidence should aim to improve fatigue, depression, and cognition in addition to physical components.

Center-Based Group and Home-Based Individual Exercise Programs Have Similar Impacts on Gait and Balance in People With Multiple Sclerosis: A Randomized Trial

BACKGROUND

Group and home-based exercises to improve function in people with multiple sclerosis (MS) are common but have little underpinning evidence.

OBJECTIVE

To determine the comparative effectiveness of a center-based group versus home-based individual 8-week exercise program to improve gait and balance in people with MS.

DESIGN

Prospective, randomized controlled trial.

SETTING

Community center-based and home-based exercise program.

PARTICIPANTS

Fifty people with MS were randomized and completed allocated intervention (n = 26 center, n = 24 home), 47 completed post-assessment and 44 follow-up assessment.

METHODS

The center- and home-based groups completed an 8-week progressive functional and balance training exercise program. The center-based groups of four to six were supervised by a physiotherapist. The home-based group was provided with telephone support.

MAIN OUTCOME MEASUREMENTS

The primary outcome was gait speed (10-meter walk test). Secondary outcomes were gait endurance (6-minute walk test) and balance (Berg Balance Scale). Outcome assessments were conducted at baseline, immediately postintervention and at 8-week follow-up.

RESULTS

There was no statistically significant difference between groups in gait speed post training, with a mean difference of 0.01 m/s, 95% CI -0.36 to 0.37. There were no group effects, time effects, or interactions for gait speed, endurance, or balance. In both groups, gait speed improved to a level that met minimal clinically important differences.

CONCLUSIONS

Gait speed, endurance, and balance did not statistically improve in either group; however, gait speed changes met minimally important differences.

Effect of 4 Weeks of Foot Orthosis Intervention on Ambulatory Capacities and Posture in Normal-Weight and Obese Patients

BACKGROUND

Several works have shown the benefits of foot orthosis intervention on postural stability in healthy individuals and patients with foot malalignment. However, the effects of foot orthoses on the daily ambulatory activities explored by the Six-Minute Walk Test (6MWT) were never examined. We hypothesized that foot orthoses could increase the gait distance and attenuate the post-6MWT posture alterations already reported in healthy individuals.

METHODS

In ten normal-weight (NW) and ten obese patients with foot malalignment and/or abnormal foot arch, we examined the benefits of 4 weeks of custom-molded orthosis intervention (D30) on 6MWT gait distance, fatigue sensation scores, ankle plantarflexion force, and post-6MWT sway of the center of pressure (COP) measured by a pedobarographic platform. Data were compared with those measured in two control-matched groups of ten NW and ten obese individuals, explored at study inclusion and at D30.

RESULTS

At study inclusion, the post-6MWT changes in COP surface and the medial and lateral COP deviations were significantly higher in obese participants who needed to wear the foot orthoses compared with obese control subjects. The foot orthosis intervention significantly improved the ambulatory performances of NW and obese individuals during the 6MWT, attenuated the bodily fatigue sensation after the 6MWT, and reduced the post-6MWT COP deviations, with the benefits of insoles being significantly accentuated in obese participants.

CONCLUSIONS

Four weeks of foot orthosis intervention significantly increases gait distance and is an effective means to reduce postural sway after walking.

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

BACKGROUND

The 6-minute walk (6 MW) is the most commonly applied measure of endurance walking capacity in persons with multiple sclerosis (MS); however, we are not aware of a quantitative synthesis of 6 MW performance in MS.

RESEARCH QUESTION

We undertook a meta-analysis quantifying the overall magnitude of difference in 6 MW performance between MS and healthy controls (HCs), and then within MS as a function of disability status. We further examined possible moderator variables of 6 MW performance.

METHODS

The systematic search was conducted for articles that included the 6 MW in persons with MS and involved comparison groups (i.e., HCs or MS disability subgroups (i.e., mild vs moderate-to-severe disability status)). The mean and standard deviation of the distance traveled during the 6 MW as well as sample sizes were entered into Comprehensive Meta-Analysis software and we estimated the overall effect size (Cohen's d) using a random effects model and examined categorical variables as possible moderators (e.g., instruction protocol, provision of encouragement, method of distance measurement, and course description).

RESULTS

Thirty-four studies met inclusion criteria with a total sample size of 3204 persons (MS: 2683; HC: 521) yielding 42 total comparisons. Persons with MS walked a shorter distance than HCs (mean difference = -177.2 ± 19.1 m) with a large effect size (d = - 1.87). Persons with mild disability walked further than those with moderate-to-severe disability (mean difference = 185.19 ± 9.2 m) with a large effect (d = 1.83). The categorical variables of provision of encouragement and course layout moderated the effect of MS and course layout moderated the effect of disability status on 6 MW performance.

SIGNIFICANCE

This meta-analysis of 6 MW performance defines mean difference in 6 MW performance in MS compared with HCs and provides an estimate of the disease-related effect of MS on endurance walking capacity for application within clinical research and practice.

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

Background

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

Methods

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

Results

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

Conclusions

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

Two-minute versus 6-minute walk distances during 6-minute walk test in neuromuscular disease: Is the 2-minute walk test an effective alternative to a 6-minute walk test?

Functional tests such as Motor Function Measure-32 (MFM-32), supine to stand, ascend/descend stairs permit the assessment of task-specific motor function in neuromuscular disease (NMD). The 6-min walk test (6MWT), though functional, is primarily used to assess endurance and disease progression in children with neuromuscular disorders. Barriers to 6MWT administration, in this population, can include reduced attention span due to age and inability to tolerate test length due to weakness. We propose task-specific functional deficits are related to endurance. Additionally, the 2-min walk test (2MWT) could effectively replace the 6MWT in this population. Seventy-seven participants, ages 5-18, with a variety of neuromuscular disorders performed the 6MWT, timed functional tests (TFT), and the MFM-32. Correlation and paired t-test analyses were used to compare the distance walked in the first 2 min (2MWD) to the distance walked in the entire 6 min (6MWD) and to the functional outcome measures above. The 2MWD strongly correlated with 6MWD and the other outcome measures. Paired t-test analysis also showed that the 2MWD did not differ from the distance walked in the last 2 min of the 6MWT. Although equivalence testing could not reject the claim that this difference exceeded the upper practical limit of 9.5 m, it only showed a modest overestimation of the 4-6MWD compared with the 2MWD. Together, our results support the ability of the 2MWD to predict the 6MWD, specifically in the pediatric neuromuscular disease population.

Dalfampridine benefits ambulation but not cognition in multiple sclerosis

Background:

Impaired cognition and ambulation are common in multiple sclerosis (MS). Dalfampridine is the first Food and Drug Administration (FDA)–approved medication to treat impaired ambulation in MS. Dalfampridine may benefit patients with cognitive impairment, given its effects on saltatory conduction and the association between cognitive and motor function.

Objective:

To examine the effects of dalfampridine on cognition in MS. To determine if the anticipated improved cognition is grounded in dalfampridine’s effects on ambulation.

Methods:

Adults with MS were randomized to dalfampridine ( n = 45) or placebo ( n = 16) for 12 weeks. Cognition and motor function were assessed at baseline and end-point.

Results:

T25FW and 6-minute walk (6MW) performance improved at end-point in the treatment group but not in the placebo group ( p < 0.05). Our primary outcome, performance on the Symbol Digit Modalities Test, did not improve. About 30% ( n = 12) of the dalfampridine group demonstrated ⩾20% improved ambulation and were categorized “responders.” Among “responders”, Symbol Digit Modalities test performance did not improve. However, performance on the Paced Auditory Serial Addition Test improved among “responders” ( p < 0.05).

Conclusion:

Dalfampridine benefits timed ambulation but not cognition. Some improvement among ambulation “responders” is consistent with prior reports of cognition-motor coupling in MS ( ClinicalTrials.gov #: NCT02006160).

Evaluation of the Keeogo exoskeleton for assisting ambulatory activities in people with multiple sclerosis: an open-label, randomized, cross-over trial

Background

Although physical activity and exercise is known to benefit people with multiple sclerosis (MS), the ability of these individuals to participate in such interventions is difficult due to the mobility impairments caused by the disease. Keeogo is a lower-extremity powered exoskeleton that may be a potential solution for enabling people with MS to benefit from physical activity and exercise.

Methods

An open-label, randomized, cross-over trial was used to examine the immediate performance effects when using the device, and the potential benefits of using the device in a home setting for 2 weeks. Clinical performance tests with and without the device included the 6 min walk test, timed up and go test and the 10-step stair test (up and down). An activity monitor was also used to measure physical activity at home, and a patient-reported questionnaire was used to determine the amount and extent of home use. Generalized linear models were used to test for trial effects, and correlation analysis used to examine relationships between trial effects and usage.

Results

Twenty-nine patients with MS participated. All measures showed small decrements in performance while wearing the device compared to not wearing the device. However, significant improvements in unassisted (Rehab effect) performance were found after using the device at home for 2 weeks, compared to 2 weeks at home without the device, and participants improved their ability to use the device over the trial period (Training effect). Rehab and Training effects were related to the self-reported extent that participants used Keeogo at home.

Conclusions

Keeogo appears to deliver an exercise-mediated benefit to individuals with MS that improved their unassisted gait endurance and stair climbing ability. Keeogo might be a useful tool for delivering physical activity interventions to individuals with mobility impairment due to MS.

Trial registration

ClinicalTrials.gov: NCT02904382. Registered 19 September 2016 - Retrospectively registered.

Gait pattern changes after six-minute walk test in persons with multiple sclerosis

OBJECTIVE

To examine the effect of induced fatigue on spatiotemporal gait parameters in persons with multiple sclerosis (PwMS) by using 6-min walk test (6MWT).

METHODS

A cross-sectional study with a control group (25 healthy persons) was performed. Fifty-six PwMS (37 female) were divided into three groups according to their level of disability, as measured by the expanded disability status scale (EDSS): mild (n = 23, EDSS = 1.0-3.5), moderate (n = 19, EDSS = 4.0-5.5), and severe (n = 12, EDSS = 6.0-6.5). Spatiotemporal gait parameters were measured by the GAITRite electronic walkway before and after 6MWT performance. In addition, to determine the level of fatigue in PwMS, the participants completed the questionnaire modified fatigue impact scale (MFIS) before performing the 6MWT. Statistical analyses were performed to compare intragroup and intergroup differences.

RESULTS

Fatigue level was lower in the mild (37.6 ± 20.5) versus moderate (54.3 ± 17.2) versus severe (53.6 ± 12.9) groups (p < 0.05). Significant differences were found among all the groups in terms of the distance walked during the 6MWT (p = 0.001) and of the spatiotemporal gait parameters: gait velocity (cm/s), cadence (steps/min), and step length (cm) decreased and, on the contrary, step time (sec), stance, and double support time (% gait cycle) increased when EDSS scores were higher (p < 0.05). The percentage of change (%) in the spatiotemporal gait parameters, after 6MWT performance, was statistically significant in the moderate and severe groups: gait velocity (-8.8%, -25.9%) and step length (-6.5%, -13.4%) decreased, whereas step time (3.0%, 15.0%), double support time (8.8%, 19.1%), step time asymmetry (32.1%, 64.0%), and single support asymmetry (60.0%, 74.7%) increased (p < 0.05).

CONCLUSIONS

Gait pattern worsen after performing a walking-induced fatigue test, such as 6MWT, in moderate-severe PwMS (EDSS ≥ 4.0). Identifying these gait alterations will allow physiotherapists to determine specific therapeutic objectives.

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

Background

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

Methods

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

Results

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

Conclusions

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

Exploring cued and non-cued motor imagery interventions in people with multiple sclerosis: a randomised feasibility trial and reliability study

Background

Motor imagery (MI) is increasingly used in neurorehabilitation to facilitate motor performance. Our previous study results demonstrated significantly improved walking after rhythmic-cued MI in people with multiple sclerosis (pwMS). The present feasibility study was aimed to obtain preliminary information of changes in walking, fatigue, quality of life (QoL) and MI ability following cued and non-cued MI in pwMS. The study further investigated the feasibility of a larger study and examined the reliability of a two-dimensional gait analysis system.

Methods

At the MS-Clinic, Department of Neurology, Medical University of Innsbruck, Austria, 15 adult pwMS (1.5–4.5 on the Expanded Disability Status Scale, 13 females) were randomised to one of three groups: 24 sessions of 17 min of MI with music and verbal cueing (MVMI), with music alone (MMI), or non-cued (MI). Descriptive statistics were reported for all outcomes. Primary outcomes were walking speed (Timed 25-Foot Walk) and walking distance (6-Minute Walk Test). Secondary outcomes were recruitment rate, retention, adherence, acceptability, adverse events, MI ability (Kinaesthetic and Visual Imagery Questionnaire, Time-Dependent MI test), fatigue (Modified Fatigue Impact Scale) and QoL (Multiple Sclerosis Impact Scale-29). The reliability of a gait analysis system used to assess gait synchronisation with music beat was tested.

Results

Participants showed adequate MI abilities. Post-intervention, improvements in walking speed, walking distance, fatigue, QoL and MI ability were observed in all groups. Success of the feasibility criteria was demonstrated by recruitment and retention rates of 8.6% (95% confidence interval, CI 5.2, 13.8%) and 100% (95% CI 76.4, 100%), which exceeded the target rates of 5.7% and 80%. Additionally, the 83% (95% CI 0.42, 0.99) adherence rate surpassed the 67% target rate. Intra-rater reliability analysis of the gait measurement instruments demonstrated excellent Intra-Class Correlation coefficients for step length of 0.978 (95% CI 0.973, 0.982) and step time of 0.880 (95% CI 0.855, 0.902).

Conclusion

Results from our study suggest that cued and non-cued MI are valuable interventions in pwMS who were able to imagine movements. A larger study appears feasible, however, substantial improvements to the methods are required such as stratified randomisation using a computer-generated sequence and blinding of the assessors.

Trial registration

ISRCTN ISRCTN92351899. Registered 10 December 2015.

Electronic supplementary material

The online version of this article (10.1186/s40945-018-0045-0) contains supplementary material, which is available to authorized users.

Motor unit discharge characteristics and walking performance of individuals with multiple sclerosis

Walking performance of persons with multiple sclerosis (MS) is strongly influenced by the activation signals received by lower leg muscles. We examined the associations between force steadiness and motor unit discharge characteristics of lower leg muscles during submaximal isometric contractions with tests of walking performance and disability status in individuals who self-reported walking difficulties due to MS. We expected that worse walking performance would be associated with weaker plantar flexor muscles, worse force steadiness, and slower motor unit discharge times. Twenty-three individuals with relapsing-remitting MS (56 ± 7 yr) participated in the study. Participants completed one to three evaluation sessions that involved two walking tests (25-ft walk and 6-min walk), a manual dexterity test (grooved pegboard), health-related questionnaires, and measurement of strength, force steadiness, and motor unit discharge characteristics of lower leg muscles. Multiple regression analyses were used to construct models to explain the variance in measures of walking performance. There were statistically significant differences (effect sizes: 0.21-0.60) between the three muscles in mean interspike interval (ISI) and ISI distributions during steady submaximal contractions with the plantar flexor and dorsiflexor muscles. The regression models explained 40% of the variance in 6-min walk distance and 47% of the variance in 25-ft walk time with two or three variables that included mean ISI for one of the plantar flexor muscles, dorsiflexor strength, and force steadiness. Walking speed and endurance in persons with relapsing-remitting MS were reduced in individuals with longer ISIs, weaker dorsiflexors, and worse plantar flexor force steadiness. NEW & NOTEWORTHY The walking endurance and gait speed of persons with relapsing-remitting multiple sclerosis (MS) were worse in individuals who had weaker dorsiflexor muscles and greater force fluctuations and longer times between action potentials discharged by motor units in plantar flexor muscles during steady isometric contractions. These findings indicate that the control of motor unit activity in lower leg muscles of individuals with MS is associated with their walking ability.

Psychometric properties of measures of gait quality and walking performance in young people with Cerebral Palsy: A systematic review

Availability of outcome measures (OMs) with robust psychometric properties is an essential prerequisite for the evaluation of interventions designed to address gait deterioration in young people with Cerebral Palsy (CP). This review evaluates evidence for the reliability, validity and responsiveness of outcome measures of gait quality and walking performance in young people with CP. A systematic search was performed in MEDLINE, CINAHL, PubMed and Scopus. Articles that met the eligibility criteria were selected. Methodological quality of studies was independently rated by two raters using the modified COnsensus-based Standard for the selection of health status Measurement INstruments checklist. Strength of evidence was rated using standardised guidelines. Best evidence synthesis was scored according to Cochrane criteria. Fifty-one articles reporting on 18 distinct OMs were included for review. Best evidence synthesis indicated a moderate to strong evidence for the reliability for OMs of walking performance but conflicting evidence for the reliability of OMs of gait quality. The evidence for responsiveness for all OMs included in this review was rated as 'unknown'. The limitations of using the modified COSMIN scoring for small sample sizes are acknowledged. Future studies of high methodological quality are needed to explore the responsiveness of OMs assessing gait quality and walking performance in young people with CP.

Maximum inspiratory pressure as a clinically meaningful trial endpoint for neuromuscular diseases: a comprehensive review of the literature

Respiratory muscle strength is a proven predictor of long-term outcome of neuromuscular disease (NMD), including amyotrophic lateral sclerosis, Duchenne muscular dystrophy, and spinal muscular atrophy. Maximal inspiratory pressure (MIP), a sensitive measure of respiratory muscle strength, one of several useful tests of respiratory muscle strength, is gaining interest as a therapeutic clinical trial endpoint for NMD. In this comprehensive review we investigate the use of MIP as a measure of respiratory muscle strength in clinical trials of therapeutics targeting respiratory muscle, examine the correlation of MIP with survival, quality of life, and other measures of pulmonary function, and outline the role of MIP as a clinically significantly meaningful outcome measure. Our analysis supports the utility of MIP for the early evaluation of respiratory muscle strength, especially of the diaphragm, in patients with NMD and as a surrogate endpoint in clinical trials of therapies for NMD.

Effect of the 6-minute walk test on plantar loading and capability to produce ankle plantar flexion forces

The six-minute walk test (6MWT) is used to evaluate the ambulatory capacity of patients suffering from respiratory disorders, obesity or neuromuscular diseases. Our primary aim was to evaluate the effects of the 6MWT on the postural sway and the ankle plantar flexion forces in healthy subjects. We measured the ankle plantar flexion forces and the plantar contact area before and after a 6MWT in normal weight and overweight subjects with no history of respiratory, cardiac, and neuromuscular disorders. A post-6MWT sensation of bodily fatigue was evaluated by Multidimensional Fatigue Inventory (MFI) and Pichot fatigue scales. A computerized pedobarographic platform was used to collect the mean plantar contact area, the changes of the center of pressure (CoP) surface and its medial and lateral deviations. In a limited number of subjects, the reproducibility of all the measurements was explored. In both groups, the 6MWT elicited a sensation of bodily fatigue. It also significantly reduced the ankle plantar flexion forces, and increased both the mean plantar contact area and the CoP surface, the changes being not apparent after 10min. The post-6MWT lateral CoP deviations were accentuated in normal weight subjects, while an increase in medial CoP deviations occurred in overweight ones. The 6MWT-induced changes in the plantar flexion force and pedobarographic variables were reproducible. Because this study clearly showed some post-6MWT alterations of the subjects' posture sway of our subjects, we questioned the possible mechanisms occurring that could explain the altered muscle force and the transient destabilization of posture after the 6MWT.

Does the six-minute walk test measure walking performance or physical fitness in persons with multiple sclerosis?

BACKGROUND

There is psychometric evidence that supports the six-minute walk (6MW) as a measure of walking performance, whereas other psychometric data support it as a submaximal measure of physical fitness in persons with MS.

OBJECTIVE

The current cross-sectional study compared measures of walking performance and physical fitness as head-to-head predictors of 6MW distance in a sample of persons with MS across the disability spectrum.

METHODS

All participants completed the 6MW test, as well as other measures of walking performance (i.e., timed-25 foot walk, gait velocity captured by a GaitRite electronic walkway) and physical fitness (i.e., peak aerobic capacity, lower limb muscular strength).

RESULTS

6MW distance was strongly associated with measures of walking performance and physical fitness, though the correlations were significantly stronger for measures of walking performance than physical fitness (z >  4.04, p <  0.01). Walking performance explained a large portion of variance in 6MW distance (R2 >  0.85), and measures of physical fitness explained minimal variance in 6MW distance over-and-above that of measures of walking performance (ΔR2 <  0.06).

CONCLUSIONS

The current results suggest that 6MW distance is primarily a measure of walking performance rather than aerobic and muscular fitness in MS.

Are Changes in Gait and Balance Across the Disease Step Rating Scale in Multiple Sclerosis Statistically Significant and Clinically Meaningful?

OBJECTIVES

To explore differences in gait endurance, speed, and standing balance in people with multiple sclerosis (MS) across the Disease Step Rating Scale, and to determine if differences are statistically significant and clinically meaningful.

DESIGN

Observational study.

SETTING

Community rehabilitation - primary health care center.

PARTICIPANTS

Community-dwelling people with MS (N=222; mean age, 48±12y; 32% men).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Participants were categorized using the Disease Step Rating Scale. Demographics and clinical measures of gait endurance (6-minute walk test [6MWT]), gait speed (10-m walk test [10MWT] and 25-foot walk test [25FWT]), and balance (Berg Balance Scale [BBS]) were recorded in 1 session. Differences in these parameters across categories of the Disease Step Rating Scale were explored, and clinically meaningful differences were identified.

RESULTS

The 6MWT showed a greater number of significant differences across adjacent disease steps in those with less disability (P<.001), whereas the 10MWT and 25FWT demonstrated more significant changes in those with greater disability (P<.001). The BBS demonstrated significant differences across the span of the Disease Step Rating Scale categories (P<.001). Differences in gait and balance between adjacent Disease Step Rating Scale categories met most previously established levels of minimally detectable change and all minimally important change scores.

CONCLUSIONS

Our findings support the Disease Step Rating Scale is an observational tool that can be used by health professionals to categorize people with MS, with the categories reflective of statistically significant and clinically meaningful differences in gait and balance performance.

Factors associated with the 6-minute walk test in nursing home residents and community-dwelling older adults

[Purpose] The main objective of this study was to determine the contributions and extent to which certain physical measurements explain performance in the 6-minute walk test in healthy older adults living in a geriatric nursing home and for older adults dwelling in the community. [Subjects] The subjects were 122 adults aged 65 and older with no cognitive impairment who were independent in their daily activities. [Methods] The 6-minute walk test, age, body mass index, walking speed, chair stand test, Berg Balance Scale, Timed Up-and-Go test, rectus femoris cross-sectional area, Short Physical Performance Battery, and hand-grip strength were examined. [Results] Strong significant associations were found between mobility, lower-limb function, balance, and the 6-minute walk test. A stepwise multiple regression on the entire sample showed that lower-limb function was a significant and independent predictor for the 6-minute walk test. Additionally, lower-limb function was a strong predictor for the 6-minute walk test in our nursing home group, whereas mobility was found to be the best predictor in our community-dwelling group. [Conclusion] Better lower-limb function, balance, and mobility result in a higher distance covered by healthy older adults. Lower-limb function and mobility appeared to best determine walking performance in the nursing home and community-dwelling groups, respectively.

Sit-to-stand biomechanics of individuals with multiple sclerosis

BACKGROUND

It is unclear how people with multiple sclerosis, who often have compromised strength and balance, compare to healthy controls during sit-to-stand movements. The purpose of this study was to compare sit-to-stand biomechanics among three groups: people with multiple sclerosis who exhibit leg weakness, people with multiple sclerosis who have comparable strength to controls, and healthy controls.

METHODS

Twenty-one individuals with multiple sclerosis (n=10 exhibiting leg weakness: n=11 exhibiting comparable strength to controls), and 12 controls performed five sit-to-stand trials while kinematic data and ground reaction forces were captured. ANOVAs followed by Tukey's post-hoc tests (α=0.05) were used to determine group and limb differences for leg strength, movement time, and sagittal-plane joint kinematics and kinetics.

FINDINGS

Persons with multiple sclerosis exhibiting leg weakness displayed decreased leg strength, greater trunk flexion, faster trunk flexion velocity and decreased knee extensor power compared to the other two groups (p<0.05; d≥0.87), and slower rise times compared to controls(p<0.03; d≥1.17). No differences were found between controls and the multiple sclerosis-comparable strength group. Across all 3 groups, leg strength was moderately correlated with trunk kinematics and knee extensor velocities, moments and powers of the sit-to-stand (p≤0.05).

INTERPRETATION

Participants with multiple sclerosis exhibiting leg weakness took longer to stand and appeared to use a trunk-flexion movement strategy when performing the sit-to-stand. The majority of group differences appear to be a result of leg extension weakness. Treatment that includes leg strengthening may be necessary to improve sit-to-stand performance for people with multiple sclerosis.

Prevalence of Walking-Related Motor Fatigue in Persons With Multiple Sclerosis: Decline in Walking Distance Induced by the 6-Minute Walk Test

OBJECTIVE

To investigate the individual occurrence of walking-related motor fatigue in persons with multiple sclerosis (PwMS), according to disability level and disease phenotype.Study design This was a cross-sectional, multinational study.Participants They were 208 PwMS from 11 centers with Expanded Disability Status Scale (EDSS) scores up to 6.5.

METHODS

The percentage change in distance walked (distance walked index, DWI) was calculated between minute 6 and 1 (DWI(6-1)) of the 6-Minute Walk Test (6MWT). Its magnitude was used to classify participants into 4 subgroups: (1) DWI(6-1)[≥5%], (2) DWI(6-1)[5%; -5%], (3) DWI(6-1)[-5%; > -15%], and (4) DWI(6-1)[≤-15%]. The latter group was labeled as having walking-related motor fatigue. PwMS were stratified into 5 subgroups based on the EDSS (0-2.5, 3-4, 4.5-5.5, 6, 6.5) and 3 subgroups based on MS phenotype (relapsing remitting [RR], primary progressive [PP], and secondary progressive [SP]).

RESULTS

The DWI6-1was ≥5% in 16 PwMS (7.7%), between 5% and -5% in 70 PwMS (33.6%), between -5% and -15% in 58 PwMS (24%), and ≤-15% in 64 PwMS (30.8%). The prevalence of walking-related motor fatigue (DWI(6-1)[≤-15%]) was significantly higher among the progressive phenotype (PP = 50% and SP = 39%; RR = 15.6%) and PwMS with higher disability level (EDSS 4.5-5.5 = 48.3%, 6 = 46.3% and 6.5 = 51.5%, compared with EDSS 0-2.5 = 7.8% and 3-4 = 16.7%;P< .05). Stepwise multiple regression analysis indicated that EDSS, but not MS phenotype, explained a significant part of the variance in DWI(6-1)(R(2)= 0.086;P< .001).

CONCLUSION

More than one-third of PwMS showed walking-related motor fatigue during the 6MWT, with its prevalence greatest in more disabled persons (up to 51%) and in those with progressive MS phenotype (up to 50%). Identification of walking-related motor fatigue may lead to better-tailored interventions.

Ecological validity of walking capacity tests in multiple sclerosis

Background

Ecological validity implicates in how far clinical assessments refer to real life. Short clinical gait tests up to ten meters and 2- or 6-Minutes Walking Tests (2MWT/6MWT) are used as performance-based outcomes in Multiple Sclerosis (MS) studies and considered as moderately associated with real life mobility.

Objective

To investigate the ecological validity of 10 Meter Walking Test (10mWT), 2MWT and 6MWT.

Methods

Persons with MS performed 10mWT, 6MWT including 2MWT and 7 recorded days by accelerometry. Ecological validity was assumed if walking tests represented a typical walking sequence in real-life and correlations with accelerometry parameters were strong.

Results

In this cohort (n=28, medians: age=45, EDSS=3.2, disease duration=9 years), uninterrupted walking of 2 or 6 minutes occurred not frequent in real life (2.61 and 0.35 sequences/day). 10mWT correlated only with slow walking speed quantiles in real life. 2MWT and 6MWT correlated moderately with most real life walking parameters.

Conclusion

Clinical gait tests over a few meters have a poor ecological validity while validity is moderate for 2MWT and 6MWT. Mobile accelerometry offers the opportunity to control and improve the ecological validity of MS mobility outcomes.

Measures of respiratory function correlate with fatigue in ambulatory persons with multiple sclerosis

PURPOSE

This article examines the association between measures of respiratory muscle function and fatigue in individuals with mild-to-moderate disability multiple sclerosis (MS).

METHODS

This was a cross-sectional study of 37 ambulatory volunteers with MS (28 F/9 M, 52.7 ± 10.2 years, Expanded Disability Status Scale [EDSS] = 3.5 ± 1.9). No patients withdrew from the study. Primary outcome variables included measures of respiratory function: maximal inspiratory (MIP) and expiratory pressures (MEP), forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁), maximal voluntary ventilation (MVV₁₂); and a self-reported measure of fatigue: the Modified Fatigue Impact Scale (MFIS). Secondary measures included 6-min walking test (6MWT), a timed stair climb, the Short Form (SF)-36, the Epworth Sleepiness Scale and the Physical Activity and Disability Scale (PADS).

RESULTS

Significant correlations were shown between expiratory muscle strength (MEP) and the MFIS total (p < 0.03, r = -0.362) and between MEP and physical fatigue scores (p < 0.03, r = -0.360), as well as between MVV₁₂ percent predicted (respiratory muscle endurance) and both the 6MWT (p = 0.045, r = 0.346) and the Epworth Sleepiness Scale (p = 0.006, r = 0.447).

CONCLUSIONS

Respiratory muscle performance is correlated with perceived fatigue (MFIS), whereas respiratory endurance correlated to reductions in physical function and sleep quality among individuals with mild-to-moderate severity MS. Implications for Rehabilitation Multiple sclerosis (MS) results in peripheral and respiratory muscle weakness and affected individuals report fatigue as one of their most disabling symptoms. Expiratory muscle strength was correlated with self-reported physical fatigue, while respiratory muscle endurance was correlated with functional performance and sleepiness. Respiratory muscle strength was not correlated with lung spirometry testing. These findings highlight the importance of considering the effects of respiratory muscle weakness when evaluating causes of fatigue among individuals with mild-to-moderate MS.

Walking Distance as a Predictor of Falls in People With Multiple Sclerosis

Background and Purpose

People with multiple sclerosis (PwMS) experience falls, usually when walking and transferring. The aim was to investigate if walking distance and patient overestimate of walking distance are predictors of falls in PwMS.

Methods

A prospective study was conducted, with a single test occasion followed by prospective registration of falls for 3 months. All PwMS in Region Örebro County with a previously registered Expanded Disability Status Scale score between 3.0 and 7.0 in the Swedish MS Registry were invited to participate (n = 149). Altogether, data from 49 PwMS being relapse free for at least 3 months and with a confirmed Expanded Disability Status Scale between 1.5 and 7.0 upon study entry were analysed.

Results

Twenty‐two PwMS (45%) fell during the study period, providing information of 66 falls. Walking distance or overestimate of one's walking distance, as compared with test results, did not predict falls in this MS sample.

Discussion

Walking and standing activities are associated with numerous falls in PwMS. Our data do not clearly support routine measurements of walking distance in assessing individual fall risk. © 2015 The Authors. Physiotherapy Research International published by John Wiley & Sons, Ltd.

Dorsiflexion assist orthosis reduces the physiological cost and mitigates deterioration in strength and balance associated with walking in people with multiple sclerosis

OBJECTIVE

To evaluate the effect of wearing a dorsiflexion assist orthosis (DAO) on walking distance, physiological cost, fatigue, and strength and balance measures after a modified 6-minute walk test (6MWT) in people with multiple sclerosis (MS).

DESIGN

Randomized crossover trial.

SETTING

Hospital Movement Laboratory.

PARTICIPANTS

People with moderate MS and Expanded Disability Status Scale score of 3.7±0.7 (N=34; 26 women).

INTERVENTIONS

Modified 6MWT with and without a DAO worn on the weaker leg.

MAIN OUTCOME MEASURES

Distance walked, perceived fatigue, and the physiological cost of walking were compared between walking conditions. Pre- and postwalk changes in knee extensor and ankle dorsiflexor isometric strength and standing postural sway with eyes open and closed were compared between walking conditions.

RESULTS

There were no differences in distance walked or perceived fatigue between the 2 walking conditions. However, there was a reduced physiological cost of walking (P<.05), a smaller reduction in knee extensor strength (P<.05), and a smaller increase in standing postural sway with eyes open (P<.01) after walking while wearing the DAO compared with walking without wearing the DAO.

CONCLUSIONS

Despite not increasing walking distance or reducing perceived fatigue, the DAO reduced the physiological cost of walking and maintained knee strength and standing balance, which may have important implications for physical rehabilitation in people with MS. Further trials are required to determine whether the beneficial effects of wearing a DAO found here are maintained for longer periods.

Does fatigue occur in MS patients without disability?

BACKGROUND

Motor dysfunction and fatigue are the most common impairments that are associated with multiple sclerosis (MS). Walk tests and scales demonstrate the presence of fatigue in patients with MS with different levels of disability.

OBJECTIVE

To evaluate objective and subjective fatigue in MS patients without disability.

METHODS

Were selected MS patients with relapsing remitting clinical course, from 18 to 55 years old and EDSS 0 to 1.5; controls were paired for age, gender, body mass index, and physical activity level. Fatigue caused by pulmonary diseases, anemia, diabetes, thyroid disease, psychiatry diseases (except depression), and orthopedic and rheumatologic diseases are excluded. All participants performed the 6-minute walk test (6MWT), the MS Functional Composite (MSFC), and completed the Modified Fatigue Impact Scale (MFIS) and the Beck Depression Inventory. A multivariate model was applied to identify the variables associated with fatigue.

RESULTS

54 individuals were selected (31 patients; 23 controls). In the MSFC and 6MWT, no significant difference was observed between the groups. A MFIS total score indicated fatigue in 35% of the patients, 42% in the physical domain, 25.8% in the cognitive domain, and 29% in the psychosocial domain, which differed from the controls in all comparisons. Fatigue was associated with MS, low-physical activity, and mood disorders.

CONCLUSIONS

Fatigue occurs in patients with MS in the absence of motor dysfunction and is associated with the disease itself, the sedentary lifestyle, and mood disorders. The 6MWT is not useful to demonstrate motor fatigue in subjects without neurological disability.

Is walking capacity in subjects with multiple sclerosis primarily related to muscle oxidative capacity or maximal muscle strength? A pilot study

Background and Purpose. Walking capacity is reduced in subjects with multiple sclerosis (MS). To develop effective exercise interventions to enhance walking capacity, it is important to determine the impact of factors, modifiable by exercise intervention (maximal muscle strength versus muscle oxidative capacity), on walking capacity. The purpose of this pilot study is to discriminate between the impact of maximal muscle strength versus muscle oxidative capacity on walking capacity in subjects with MS. Methods. From 24 patients with MS, muscle oxidative capacity was determined by calculation of exercise-onset oxygen uptake kinetics (mean response time) during submaximal exercise bouts. Maximal muscle strength (isometric knee extension and flexion peak torque) was assessed on dynamometer. All subjects completed a 6-minute walking test. Relationships between walking capacity (as a percentage of normal value) and muscle strength (of knee flexors and extensors) versus muscle oxidative capacity were assessed in multivariate regression analyses. Results. The expanded disability status score (EDSS) showed a significant univariate correlation (r = −0.70, P < 0.004) with walking capacity. In multivariate regression analyses, EDSS and mean response time, but not muscle strength, were independently related to walking capacity (P < 0.05). Conclusions. Walking distance is, next to disability level and not taking neurologic symptoms/deficits into account, primarily related to muscle oxidative capacity in subjects with MS. Additional study is needed to further examine/verify these findings.

Gait and six-minute walk performance in persons with multiple sclerosis

The six-minute walk (6 MW) has been established as a clinic-based, performance measure of walking endurance that reflects community ambulation in multiple sclerosis (MS). Consequently, identifying the contribution of variables to 6 MW performance may provide targets for improving real-life walking in MS, and these variables may differ as a function of disability. This study examined cadence and stride length as gait variables that explain differences in 6 MW performance between persons with MS and controls, and by level of disability. 256 community-residing persons with MS and 49 non-MS controls performed a standard 6 MW test and completed 2 trials of comfortable walking on an electronic walkway for quantifying gait. Regression analyses indicated that cadence and stride length explain differences in 6 MW performance between MS and controls, and by level of disability in MS. The contribution of cadence and stride length to walking endurance differed as a function of disability, such that cadence and to a greater extent stride length explained variance in 6 MW performance in mild MS, whereas cadence and stride length explained approximately an equivalent amount of variance in 6 MW performance in moderate-to-severe MS. We provide evidence for intervention strategies that are specific to disability level to improve walking endurance in MS.

Gait impairment and optimizing mobility in multiple sclerosis

Multiple sclerosis (MS) is an immune-mediated disease that causes demyelination and degeneration within the brain and spinal cord. This may result in many impairments, including impaired ambulation, muscle weakness, abnormal tone, visual disturbances, decreased sensation, and fatigue. Rehabilitation helps patients with MS maximize independence by helping to manage and minimize impairments. Deficits seen in ambulation should be addressed to improve energy efficiency and reduce falls. Compensation through appropriate prescription of assistive devices, bracing, and wheelchairs will help improve safety. Rehabilitation can make a significant impact on achieving and maintaining quality of life and independence.

The association between multiple sclerosis-related fatigue and balance as a function of central sensory integration

BACKGROUND

Fatigue and impaired upright postural control (balance) are the two most common complaints in persons with multiple sclerosis (MS), with limited evidence on how they are related.

OBJECTIVE

To examine the relationship between symptomatic fatigue and balance as a function of central sensory integration in persons with multiple sclerosis.

MATERIALS AND METHODS

Seventeen persons with relapsing-remitting MS were enrolled in this cross-sectional study. Primary measurements included fatigue (modified fatigue impact scale - MFIS); balance (dynamic posturography, sensory organization testing - SOT); and walking capacity (six-minute walk test - 6MWT).

RESULTS

Fatigue scores were significantly associated with balance: MFIS total (r=-0.78; p<0.001), physical subscale (r=-0.77; p<0.001), cognitive subscale (r=-0.75; p=0.001) and psychosocial subscale (r=-0.53; p=0.030) scores. MFIS total score was a significant predictor of balance (p≤0.001), accounting for 62% of the variability in SOT composite scores. Significant differences in fatigue (d=1.75; p=0.005) and balance (d=1.74; p=0.005) were found for participants who had cerebellar and brainstem involvement compared to those without.

CONCLUSIONS

Symptomatic fatigue is significantly related to balance and is a significant predictor of balance as a function of central sensory integration in persons with MS. Fatigue and balance are associated with cerebellar and brainstem involvement. This study provides early evidence supporting the theory that for those persons with MS who struggle to maintain steady balance during tasks that stimulate the central sensory integration process, complaints of significant levels of fatigue are probable.

An exploration of impaired walking dynamics and fatigue in multiple sclerosis

Background

Physical disability in multiple sclerosis (MS) is frequently characterized by impaired ambulation. Although walking tests have been successfully employed to assess walking ability in MS patients, data analytic procedures have predominantly relied on result-oriented parameters (e.g. total distance covered during a given amount of time), whereas process-oriented, dynamic walking patterns have mostly been ignored. This is striking, since healthy individuals have been observed to display a stereotypical U-shaped pattern of walking speed during timed walking, characterized by relatively high speed during the initial phase, subsequent slowing and final acceleration. Objective of the current study was to test the utility of the 6 min Walk (6MW) and the 12 min Walk (12MW) for revealing putatively abnormal temporal dynamic features of walking in MS.

Methods

A group of 37 MS patients was divided into subgroups with regard to their level of disability analyzed with the Expanded Disability Status Scale (EDSS; Mild MS Group, n = 20, EDSS 0 – 3.5; Moderate MS Group, n = 17, EDSS 4 – 5). Subsequently, both groups were compared to age-matched healthy controls (n = 25) on both tests with regard to result-oriented characteristics (mean walking speed), as well as dynamic features (mean decline in walking speed, degree of observed U-shape).

Results

Both MS groups showed a significantly lower mean walking speed than healthy controls, independent of test duration. Compared to controls, the Moderate MS Group also slowed down more rapidly throughout both tests. The same pronounced decline in walking speed was observed for the Mild MS Group in case of the 12MW. Additionally, for both MS groups an attenuated U-shaped velocity pattern was observed relative to controls in the 6MW. Patients' subjective fatigue scores were more strongly correlated with the decline in walking speed than with the common parameter of mean walking speed in the 6MW.

Conclusions

MS patients display abnormal dynamics in their walking patterns. A pronounced linear decline in walking speed can be identified with the 12MW even in MS patients with seemingly mild disability. Similarly, the 6MW can be used to assess an abnormal walking profile. Particularly the linear decline in walking speed on this test shows a more robust association with subjective fatigue than mean walking speed. Dynamic walking parameters may hence represent valuable clinical features, serving as surrogate measures of motor fatigue. Future studies are needed to verify their prognostic value.