Neurological disability and its association with walking impairment in multiple sclerosis: brief review

Disability Moderates Dual Task Walking Performance and Neural Efficiency in Older Adults With Multiple Sclerosis

BACKGROUND

Mobility and cognitive impairment are prevalent and co-occurring in older adults with multiple sclerosis (OAMS), yet there is limited research concerning the role of disability status in the cognitive control of gait among OAMS.

OBJECTIVE

We investigated the levels of prefrontal cortex (PFC) activation, using oxygenated hemoglobin (HbO2), during cognitively-demanding tasks in OAMS with lower and higher disability using functional near-infrared spectroscopy (fNIRS) to: (1) identify PFC activation differences in single task walk and cognitively-demanding tasks in OAMS with different levels of disability; and (2) evaluate if disability may moderate practice-related changes in neural efficiency in OAMS.

METHODS

We gathered data from OAMS with lower (n = 51, age = 65 ± 4 years) or higher disability (n = 48, age = 65 ± 5 years), using a cutoff of 3 or more, in the Patient Determined Disease Steps, for higher disability, under 3 different conditions (single-task walk, Single-Task-Alpha, and Dual-Task-Walk [DTW]) administered over 3 counterbalanced, repeated trials.

RESULTS

OAMS who had a lower disability level exhibited decreased PFC activation levels during Single-Task-Walk (STW) and larger increases in PFC activation levels, when going from STW to a cognitively-demanding task, such as a DTW, than those with higher disability. OAMS with a lower disability level exhibited greater declines in PFC activation levels with additional within session practice than those with a higher disability level.

CONCLUSIONS

These findings suggest that disability moderates brain adaptability to cognitively-demanding tasks and demonstrate the potential for fNIRS-derived outcome measures to complement neurorehabilitation outcomes.

Nestorone (segesterone acetate) effects on neuroregeneration

Nestorone® (segesterone acetate) is a progestin with a chemical structure closely related to progesterone with high affinity and selectivity for the progesterone receptor without significant interaction with other steroid receptors. It has been developed for female and male contraception and is FDA-approved in a first long-acting contraceptive vaginal system for female contraception. Its safety has been extensively demonstrated in both preclinical and clinical studies for contraceptive indications. Nestorone was found to display neuroprotective and neuroregenerative activity in animal models of various central nervous system diseases, including multiple sclerosis, stroke, and amyotrophic lateral sclerosis. Reviewed herein are neuroprotective and myelin- regenerating properties of Nestorone in various animal models and its translational potential as a therapeutic agent for debilitating neurological diseases for which limited therapeutic options are available (Table 1).

Leveraging Emerging Technologies to Expand Accessibility and Improve Precision in Rehabilitation and Exercise for People with Disabilities

Physical rehabilitation and exercise training have emerged as promising solutions for improving health, restoring function, and preserving quality of life in populations that face disparate health challenges related to disability. Despite the immense potential for rehabilitation and exercise to help people with disabilities live longer, healthier, and more independent lives, people with disabilities can experience physical, psychosocial, environmental, and economic barriers that limit their ability to participate in rehabilitation, exercise, and other physical activities. Together, these barriers contribute to health inequities in people with disabilities, by disproportionately limiting their ability to participate in health-promoting physical activities, relative to people without disabilities. Therefore, there is great need for research and innovation focusing on the development of strategies to expand accessibility and promote participation in rehabilitation and exercise programs for people with disabilities. Here, we discuss how cutting-edge technologies related to telecommunications, wearables, virtual and augmented reality, artificial intelligence, and cloud computing are providing new opportunities to improve accessibility in rehabilitation and exercise for people with disabilities. In addition, we highlight new frontiers in digital health technology and emerging lines of scientific research that will shape the future of precision care strategies for people with disabilities.

Fall risk is related to cognitive functioning in ambulatory multiple sclerosis patients

BACKGROUND AND AIMS

Patients with multiple sclerosis (PwMS) may suffer severely from falling and gait disturbance. Cognitive dysfunction, a common condition in MS patients, may also increase falling rates, regardless of physical disability. We planned this study to determine the fall rate and risk factors in MS patients, follow patients for falls, and reveal the relationship between falls and cognitive dysfunction.

METHODS

The study was conducted on 124 patients who have RRMS diagnoses. Patients' gait speed, simultaneous gait speed during other tasks, functions of the upper extremity, balance rating, and fear of falling were evaluated with dual-task Timed-Up-and-Go-3 versions (TUG, TUG-C, TUG-M), Timed 25 Foot Walk (T25WFT), Nine Hole Peg Test (9HPT), Berg Balance Scale (BBS) and Falls Efficacy Scale-International (FES-I) tests. Cognitive functions, fatigue levels, and quality of life were measured with the Symbol Digit Modalities Test (SDMT), Fatigue Severity Scale (FSS), and Multiple Sclerosis Quality of Life (MSQoL) test. Two groups were formed as "fallers" and "non-faller patients". We monitored the patients in six months period.

RESULTS

Forty-six patients fell at least once in the last one year before the study began. Fallers were older, less educated, had lower SDMT scores and higher disability scores. Non-faller patients scored lower in FES-I, TUG, and FSS tests. SDMT scores showed statistically significant, linear, positive, and moderate correlation with BBS and 9HPT scores (r = 0.307, p = 0.038, and r = 0.320, p = 0.030, respectively).

CONCLUSION

We determined that advanced age, lower education level, and cognitive dysfunction adversely affect gait speed and balance. Among the fallers, those with lower SDMT and MoCA scores had higher falling rates. We determined that EDSS and BBS scores are predictive factors for falls in patients with MS. In conclusion, patients with cognitive impairment should be closely monitored for the risk of falling. Consideration of falls during follow-up examinations might be predictive of cognitive deterioration in patients with MS.

The Preference-Based Multiple Sclerosis Index: an assessment of its psychometric properties and translation into Turkish

PURPOSE

To translate Preference-Based Multiple Sclerosis Index (PBMSI) into Turkish, investigate its psychometric properties and differences between its two scoring algorithms: PBMSI-Rating Scale (PBMSI-RS) and PBMSI-Standard Gamble (PBMSI-SG).

METHODS

An expert committee supervised the translation process. Psychometric properties were evaluated in 104 people with multiple sclerosis. Exploratory common factor analysis was used to investigate structural validity. Convergent validity was assessed by formulating hypotheses about correlations between PBMSI and other HRQL measures, disability level, walking-related measures, and MS symptoms. Known-groups validity was assessed against different measures of disability and walking capacity. Test-retest reliability was assessed by calculating the intraclass correlation coefficient (ICC), standard error of measurement (SEM), and minimal detectable change (MDC95%).

RESULTS

Factor analysis revealed one factor (Eigenvalue = 2.46). PBMSI-RS and PBMSI-SG correlated significantly with other measures (p < .001). Both could differentiate between individuals with different levels of disability and walking capacity (p < .05, d  ≥  0.50). Relative test-retest reliability was moderate for PBMSI-RS (ICC = 0.75) and good for PBMSI-SG (ICC = 0.83). SEM and MDC95% values were 0.16 and 0.44 for PBMSI-RS and 0.10 and 0.28 for PBMSI-SG, respectively.

CONCLUSION

Turkish version of PBMSI has good psychometric properties to assess health-related quality of life in people with multiple sclerosis. PBMSI-SG should be preferred over PBMSI-RS.IMPLICATIONS FOR REHABILITATIONHealth-related quality of life is often used as a primary or secondary endpoint in multiple sclerosis research.The Preference-Based Multiple Sclerosis Index is the first preference-based health-related quality of life measure developed in multiple sclerosis using patient preferences.Preference-Based Multiple Sclerosis Index was translated to Turkish and demonstrated good psychometric properties, including structural, convergent, known-groups validity, internal consistency, and test-retest reliability.Professionals working in the field of multiple sclerosis research and rehabilitation may benefit from using the Preference-Based Multiple Sclerosis Index as it is a short and psychometrically robust instrument.

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.

The reliability and validity of the Figure of 8 walk test in mildly disabled persons with multiple sclerosis

BACKGROUND

Figure of 8 Walk Test (F8WT) assesses the multidirectional and adaptive requirements of both straight and curved path walking. The study aimed to examine the reliability, validity, and minimal detectable change (MDC) of the F8WT in patients with Multiple Sclerosis (pwMS).

METHODS

45 mildly disabled pwMS (10 male, 35 female) were included in the study. Reliability of F8WT test was evaluated with Intraclass Correlation Coefficient (ICC). MDC estimates were calculated using baseline data. The correlation between the F8WT and Berg Balance Scale (BBS), The Timed Up and Go test (TUG), The Timed 25-Foot Walk Test (T25FW), The Four Square Step Test (FSST) was used for the validity.

RESULTS

The intra-rater (ICC 0.980-0.983) and inter-rater (ICC 0.976-0.985) reliability of the F8WT was determined to be excellent. MDC values for intra-rater were 1.04-1.08 s, and MDC values for inter-rater were 1.16-0.99 s. The correlation with F8WT and BBS (p = 0.000, r = -0.702), TUG (p = 0.000, r = 0.854), T25FW (p = 0.000, r = 0.784), FSST (p = 0.000, r = 0.748) was found to be statistically significant.

CONCLUSION

The F8WT has good reliability and validity in mildly disabled pwMS. According to the MDC results, small differences in pwMS can be adequately detected with F8WT. Therefore, it may be a clinically suitable test for detecting balance and walking.

Systematic review of participant characteristics in theory-based behavior change interventions for physical activity in multiple sclerosis: are we missing those with the greatest potential for lifelong benefits?

PURPOSE

This study examined participant characteristics, particularly disease duration, in theory-based physical activity behavior change trials in multiple sclerosis (MS) and summarized theoretical frameworks and changes in physical activity outcomes.

MATERIALS AND METHODS

PubMed, CINAHL, Embase, and Scopus were searched to identify potential trials. One reviewer screened titles and abstracts, and two reviewers then independently screened full-text articles based on predetermined eligibility criteria. Data were extracted by one reviewer and checked by a second reviewer.

RESULTS

Among 33 trials reviewed, only one trial reported a mean disease duration of less than five years (i.e., 4.5 years) for the sample. The remaining trials included samples with a mean disease duration of 6.7 years or longer. The most common theories used were Social Cognitive Theory, Trans-theoretical Model, and Motivational Interviewing. The effects on physical activity were heterogeneous; device-measured outcomes increased in 41.4% of studies, self-reported outcomes improved in 72.4%. Adherence (≥80%) was reported in 34.5% of studies.

CONCLUSIONS

There is little focus on persons with MS in the early disease course in physical activity behavior change interventions. Future research should include comprehensive theoretical approaches for more homogeneous effects across outcome measures when targeting those in the early stage and all MS populations.IMPLICATIONS FOR REHABILITATIONTheory-based physical activity behavior change interventions have not included persons with multiple sclerosis (MS) in the early disease course (<5 years since diagnosis).Disease duration has not been a criterion used to include or exclude participants in the reviewed theory-based behavior change interventions for physical activity in people with MS.The theory-based behavior change interventions in this review positively affected short-term physical activity levels in people with 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.

Effects of vibration training on motor and non-motor symptoms for patients with multiple sclerosis: A systematic review and meta-analysis

Background

Vibration therapy is one of the rehabilitation programs that may be effective in treating both motor and non-motor symptoms in Multiple Sclerosis patients. We conducted a comprehensive systematic review and meta-analysis to assess the effects of vibration therapy on motor and non-motor symptoms (functional mobility, balance, walking endurance, gait speed, fatigue, and quality of life) of this population.

Methods

A systematic search of PubMed, Embase, the Cochrane Library, Web of Science, Physiotherapy Evidence Database, Scopus, Google Search Engine, and the China National Knowledge Infrastructure (CNKI). Two reviewers independently assessed the study quality.

Results

Fourteen studies with 393 participants were finally included in the meta-analysis. The pooled results showed that vibration therapy had a significant advantage over the control intervention in improving balance function [mean difference (MD) = 2.04, 95% confidence interval (CI): 0.24-3.84, P = 0.03], and walking endurance (SMD = 0.34, 95% CI: 0.07-0.61, P = 0.01). Meanwhile, the degree of disability subgroup analysis revealed that the Expanded Disability Status Scale (EDSS) score (3.5-6) significantly improved functional mobility (MD: -1.18, 95% CI: -2.09 to 0.28, P = 0.01) and balance function (MD: 3.04, 95% CI: 0.49-5.59, P = 0.02) compared with the control group, and the EDSS (0-3.5) were more beneficial in walking endurance. The duration subgroup analysis indicated a significant difference in the effect of the duration (<4 weeks) on enhancing walking endurance (SMD: 0.46, 95% CI: 0.04-0.87, P = 0.03). However, no significant improvement was found in functional mobility, gait speed, fatigue, and quality of life.

Conclusion

Vibration therapy may improve balance function and walking endurance, and the degree of disability and duration of intervention may affect outcomes. The evidence for the effects of vibration therapy on functional mobility, gait speed, fatigue, and quality of life remains unclear. More trials with rigorous study designs and a larger sample size are necessary to provide this evidence.

Systematic Review Registration

PROSPERO, https://www.crd.york.ac.uk/prospero/#recordDetails, identifier: CRD42022326852.

Changes in Gait Characteristics During and Immediately After the 6-Minute Walk Test in Persons With Multiple Sclerosis: A Systematic Review

OBJECTIVE

There is limited information about gait patterns during prolonged walking in people with multiple sclerosis (PwMS). The aim of this review was to report on gait metrics during and immediately after the 6-Minute Walk Test (6MWT) in PwMS with different levels of disability.

METHODS

The systematic search was performed in 3 databases (PubMed, Web of Science, and SCOPUS) using keywords related to multiple sclerosis and 6MWT. Studies that reported on quantitative gait outcomes before and after the 6MWT or multiple time points during the 6MWT were included. The Hedges g effect size (ES) was calculated to determine the magnitude of change in each gait parameter.

RESULTS

Fourteen studies (n = 534 PwMS; n = 166 healthy controls) were eligible. Five studies investigated gait parameters prior to and immediately after the 6MWT. Nine studies collected gait measures during the 6MWT. Speed (ES = -0.43 to 0.19), cadence (ES = -0.46 to 0.16), step length (ES = -0.46 to 0.14), stability (ES = -0.35 to 0.33), and regularity (ES = -0.25 to -0.15) decreased in most studies. In the majority of included studies, step time (ES = 0 to 0.35), stance period (ES = 0.12 to 0.58), double support phase (ES = 0.03 to 0.62), variability (ES = -0.19 to 1.13), and asymmetry (ES = -0.79 to 0.62) increased following the 6MWT. The kinetic and kinematic (mainly in dorsiflexion angle [ES = -0.08 to -0.36]) features of gait were also negatively changed after 6 minutes of walking. Walking speed, cadence, step length, stride length, and stride time after 6MWT at a comfortable speed all increased. Changes in the majority of spatiotemporal parameters were more pronounced in PwMS with moderate-to-severe disability compared with PwMS with mild disability.

CONCLUSION

Most quantitative gait parameters deteriorated during the 6MWT, especially in PwMS with moderate-to-severe disability.

IMPACT

The deterioration of gait patterns should be considered when designing therapeutic interventions to increase sustained walking capacity.

Dietary intake and characteristics in persons with multiple sclerosis

BACKGROUND

Despite growing interest in diet and dietary interventions in persons with multiple sclerosis (PwMS), few studies have examined dietary intake and characteristics within this population. The objectives of this study were to prospectively describe and compare nutrition assessment parameters related to the diet, including daily food intake, nutrient intake, eating behaviours, and other dietary characteristics (i.e., specific diets, food preparation, and food security) between PwMS and controls without multiple sclerosis (MS).

METHODS

This study used a cross-sectional design in 60 PwMS and 60 matched controls. All participants completed a 3-day food intake record and questionnaires. Dietary intake was analysed with and without supplements using ESHA Food Processor SQL. Differences in dietary intake by group and supplement intake were examined using mixed-model ANOVAs.

RESULTS

There were differences in average daily micronutrient intake between groups for vitamins D, B12, and C, omega 3 fatty acids, and phosphorous. Through supplement use, PwMS consumed significantly more vitamin D, omega 3 fatty acids, vitamin B12, vitamin C, magnesium, manganese, and zinc than controls. There was no difference in dietary behaviours or other dietary characteristics between groups.

CONCLUSIONS

Results suggest that dietary intake was similar in persons with and without MS. The few differences in dietary intake between groups were mostly accounted for by supplement intake in PwMS. Further studies are needed to continue exploring dietary intake in PwMS.

Transcutaneous Spinal Cord Stimulation Enhances Walking Performance and Reduces Spasticity in Individuals with Multiple Sclerosis

Gait dysfunction and spasticity are common debilitating consequences of multiple sclerosis (MS). Improvements of these motor impairments by lumbar transcutaneous spinal cord stimulation (tSCS) have been demonstrated in spinal cord injury. Here, we explored for the first time the motor effects of lumbar tSCS applied at 50 Hz for 30 min in 16 individuals with MS and investigated their temporal persistence post-intervention. We used a comprehensive protocol assessing walking ability, different presentations of spasticity, standing ability, manual dexterity, and trunk control. Walking ability, including walking speed and endurance, was significantly improved for two hours beyond the intervention and returned to baseline after 24 h. Muscle spasms, clonus duration, and exaggerated stretch reflexes were reduced for two hours, and clinically assessed lower-extremity muscle hypertonia remained at improved levels for 24 h post-intervention. Further, postural sway during normal standing with eyes open was decreased for two hours. No changes were detected in manual dexterity and trunk control. Our results suggest that transcutaneous lumbar SCS can serve as a clinically accessible method without known side effects that holds the potential for substantial clinical benefit across the disability spectrum of MS.

Progress in progestin-based therapies for neurological disorders

Hormone therapy, primarily progesterone and progestins, for central nervous system (CNS) disorders represents an emerging field of regenerative medicine. Following a failed clinical trial of progesterone for traumatic brain injury treatment, attention has shifted to the progestin Nestorone for its ability to potently and selectively transactivate progesterone receptors at relatively low doses, resulting in robust neurogenetic, remyelinating, and anti-inflammatory effects. That CNS disorders, including multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), spinal cord injury (SCI), and stroke, develop via demyelinating, cell death, and/or inflammatory pathological pathways advances Nestorone as an auspicious candidate for these disorders. Here, we assess the scientific and clinical progress over decades of research into progesterone, progestins, and Nestorone as neuroprotective agents in MS, ALS, SCI, and stroke. We also offer recommendations for optimizing timing, dosage, and route of the drug regimen, and identifying candidate patient populations, in advancing Nestorone to the clinic.

Feasibility and initial efficacy of a high-intensity interval training program using adaptive equipment in persons with multiple sclerosis who have walking disability: study protocol for a single-group, feasibility trial

Background

There is considerable evidence for the efficacy of moderate-intensity continuous exercise benefitting clinically relevant outcomes in persons with multiple sclerosis (MS). However, persons with MS who have walking disability (pwMS-wd) are severely deconditioned and may achieve superior benefits by engaging in high-intensity interval training (HIIT), especially while utilizing adaptive equipment, such as recumbent arm/leg stepping (RSTEP). The proposed study will assess the feasibility of a 12-week, RSTEP HIIT program in pwMS-wd. The secondary aim will examine changes in aerobic fitness, physical activity, ambulation, upper arm function, cognition, fatigue, and depression as clinically relevant efficacy outcomes following the 12-week, RSTEP HIIT intervention.

Methods

The study will recruit 15 pwMS-wd. Feasibility will be measured via process, resource, management, and scientific outcomes throughout the entirety of the research study. The secondary, clinically relevant outcomes will consist of a neurological exam, aerobic capacity, physical activity, ambulation, cognition, upper arm function, fatigue, and depression. Outcomes will be assessed at baseline (T1), midpoint (T2, following 6 weeks), and post-intervention (T3, following 12 weeks). The intervention will involve 12 weeks of supervised, individualized HIIT sessions two to three times per week. The individual HIIT sessions will each involve 10 cycles of 60-s intervals at the wattage associated with 90% VO_2peak followed by 60 s of active recovery intervals at 15 W, totaling 20 min in length plus 5-min warm-up and cool-down periods.

Discussion

The feasibility design of the proposed study will provide experience and preliminary data for advancing towards a proof-of-concept study comparing HIIT to moderate-intensity continuous RSTEP for improving clinically relevant outcomes in a randomized control trial design. The results will be disseminated via manuscripts for publication and a report for distribution among the National Multiple Sclerosis Society.

Trial registration

ClinicalTrials.gov NCT04416243. Retrospectively registered on June 4, 2020

Social cognitive theory as a guide for exercise engagement in persons with multiple sclerosis who use wheelchairs for mobility

Multiple sclerosis (MS) is an immune-mediated neurodegenerative disease of the brain, optic nerves and spinal cord. Among persons with MS, 30% experience significant mobility impairment that requires use of a wheelchair for mobility. Exercise is an evidence-based second-line therapy that can improve mobility; however, little research has focused on individuals that use wheelchairs for mobility. Framed by social cognitive theory (SCT), we conducted a formative qualitative study examining exercise status and perceptions among 20 persons with MS who use wheelchairs for mobility. Using deductive, semantic thematic analysis, we coded for SCT variables (i.e. self-efficacy, knowledge, outcome expectations, barriers and facilitators) and identified participants as regular or inconsistent exercisers. In total, 12 participants were classified as regular exercisers and 8 inconsistent exercisers. Regular exercisers more frequently reported high self-efficacy, consistent exercise knowledge and numerous facilitators. All participants reported some positive outcome expectations and several barriers and facilitators. These findings can inform future intervention studies supporting exercise behavior change through SCT. Strategies such as increasing self-efficacy, imparting instructional materials, shaping realistic outcome expectations and providing tools directed toward overcoming barriers and identifying facilitators may work to support the exercise endeavor of persons with MS who use wheelchairs for mobility.

Gait asymmetry, and bilateral coordination of gait during a six-minute walk test in persons with multiple sclerosis

Gait impairments in persons with multiple sclerosis (pwMS) leading to decreased ambulation and reduced walking endurance remain poorly understood. Our objective was to assess gait asymmetry (GA) and bilateral coordination of gait (BCG), among pwMS during the six-minute walk test (6MWT), and determine their association with disease severity. We recruited 92 pwMS (age: 46.6 ± 7.9; 83% females) with a range of clinical disability, who completed the 6MWT wearing gait analysis system. GA was assessed by comparing left and right swing times, and BCG was assessed by the phase coordination index (PCI). Several functional and subjective gait assessments were performed. Results show that gait is more asymmetric and less coordinated as the disease progresses (p < 0.0001). Participants with mild MS showed significantly better BCG as reflected by lower PCI values in comparison to the other two MS severity groups (severe: p = 0.001, moderate: p = 0.02). GA and PCI also deteriorated significantly each minute during the 6MWT (p < 0.0001). GA and PCI (i.e., BCG) show weaker associations with clinical MS status than associations observed between functional and subjective gait assessments and MS status. Similar to other neurological cohorts, GA and PCI may be important parameters to assess and target in interventions among pwMS.

Does disability level impact the relationship of muscle strength to walking performance in people with multiple sclerosis? a cross-sectional analysis

BACKGROUND AND PURPOSE

Strength training can improve muscle weakness in people with multiple sclerosis (MS), but does not consistently improve walking. Disability level may impact the relationship of muscle weakness and walking performance in people with MS, but few studies have investigated the impact of disability on the relationship of strength and walking. The purpose of this study was to compare the relationships of strength in lower body and trunk muscles to walking performance between mild and moderate disability groups in people with MS.

METHODS

Data from 36 participants with MS who had mild disability (Expanded Disability Status Scale - EDSS 0 to 3.5) and 36 participants who had moderate disability (EDSS 4.0 to 5.5) were analyzed. Hand-held dynamometry measured strength in eight muscle groups from the ankle, knee, hip, and trunk. Timed 25-Foot Walk (T25FW) and 6-Minute Walk Test (6MWT) measured walking speed and endurance, respectively. Pearson correlations and beta coefficients (ß) were reported for each bivariate relationship of muscle strength to T25FW and 6MWT from both mild and moderate disability groups. Linear regression was then used to compare differences in beta coefficients (Δß) between disability groups for the relationship of each muscle variable to T25FW and 6MWT. A positive Δß indicated a stronger relationship of strength to walking performance in the mild disability group, while a negative Δß favored the moderate disability group.

RESULTS

Overall, there were stronger Pearson correlations between muscle strength variables to T25FW and 6MWT in the mild (r = 0.57 to 0.77) compared to moderate disability group (r = 0.10 to 0.54). The mild disability group had significantly greater beta coefficients for T25FW with ankle dorsiflexion (Δß = 0.67, 95%CI: 0.27-1.07), knee extension (Δß = 0.68, 95%CI: 0.28-1.08), and hip abduction (Δß = 0.77, 95%CI: 0.01-1.52); and for 6MWT with knee extension (Δß = 0.47, 95%CI: 0.06 to 0.88).

DISCUSSION AND CONCLUSION

For people with MS, muscle strength in the lower extremity and trunk may be a more important contributor to T25FW in mild versus moderate disability, but not for 6MWT. While more studies are needed, these results may help to inform rehabilitation intervention when prioritizing strength training to improve walking.

Quantifying muscle fatigue during walking in people with multiple sclerosis

BACKGROUND

This study aimed to examine muscle fatigue in lower leg muscles in of people with multiple sclerosis and healthy controls, and whether muscle fatigue coincided with potential changes in gait.

METHODS

In this case-control study, people with multiple sclerosis (n = 8; 3male; mean age (SD) = 49.7 (9.6) yr) and age-matched healthy controls (n = 10; 4male; mean age (SD) = 47.4 (8.7) yr) walked on a treadmill for 12-min at self-paced speed. Muscle fatigue was indirectly quantified by a decrease in median frequency and increase in root mean square of surface electromyographic recordings of lower leg muscles. Walking speed, ankle push-off power and net ankle work were calculated from marker positions and force plate data using inverse dynamic calculations.

RESULTS

People with multiple sclerosis showed larger decreases in median frequency of soleus (most affected leg: p = 0.003; least affected leg: p = 0.009) and larger increases in root mean square of soleus (most and least affected leg: p = 0.037), gastrocnemius medialis (most affected leg: p = 0.003; least affected leg: p = 0.005) and lateralis (most and least affected leg: p < 0.001) compared to controls. Walking speed (p = 0.001), ankle push-off power (most affected leg: p = 0.018; least affected leg: p = 0.001) and net work around the ankle (most affected leg: p = 0.046; least affected leg: p = 0.001) were lower in people with multiple sclerosis compared to controls, but increased in both groups.

INTERPRETATION

The results yield preliminary evidence that soleus muscles of people with multiple sclerosis fatigue during prolonged walking. Changes in electromyography of gastrocnemius muscles could however be related to muscle fatigue, changes in gait or a combination.

Functional Electrical Stimulation Cycling Exercise for People with Multiple Sclerosis

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

Muscle Dysfunction and Walking Impairment in Women with Multiple Sclerosis

Background

Recent evidence suggests that skeletal muscle dysfunction is involved in disability progression in people with multiple sclerosis (MS). However, the relationship between muscle dysfunction and walking impairments in MS remains unclear. Thus, the cross-sectional relationships between muscle-specific oxidative capacity and walking endurance in women with MS were evaluated.

Methods

Twenty women with MS (11 African American, 9 white) were tested. Muscle oxidative capacity of the medial gastrocnemius was measured using near-infrared spectroscopy after electrical stimulation. Muscle endurance was evaluated using accelerometer-based mechanomyography during electrical stimulation. Muscle strength was measured during maximal voluntary plantarflexion using handheld dynamometry. Walking function was measured using the Timed 25-Foot Walk test and the 6-Minute Walk Test (6MWT).

Results

Reduced muscle oxidative capacity (R ² = 0.68-0.71, P < .01) and muscle endurance (R ² = 0.59-0.78, P < .01) were associated with lower Timed 25-Foot Walk time and 6MWT distance. Muscle strength was weakly correlated to 6MWT distance (R ² = 0.21, P = .02). No differences in muscle function or clinical outcome measures were found between African American and white subgroups. Women with moderate-to-severe disability (Expanded Disability Status Scale [EDSS] score, 5.0-6.5) had significantly reduced muscle oxidative capacity, muscle endurance, and walking ability compared with women with mild disability (EDSS score, 2.5-4.5).

Conclusions

Reductions in muscle function in people with MS are related to declines in walking function across all levels of disability. Muscle dysfunction is not differentially related to walking impairment in African American and white women with MS.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

Rationale and design of the STEP for MS Trial: Comparative effectiveness of Supervised versus Telerehabilitation Exercise Programs for Multiple Sclerosis

BACKGROUND

We propose a Phase III trial that compares the effectiveness of an exercise training program delivered in a facility-based setting with direct, in-person supervision or a home-based setting with remote supervision via telerehabilitation for improving walking performance in persons with multiple sclerosis(MS) who have walking dysfunction and mobility disability.

METHODS/DESIGN

The study was developed with stakeholder engagement and is a multi-site trial that follows a 2-stage, randomized choice design. The trial compares the effectiveness of a 16-week evidence-based, individualized exercise program delivered in a supervised, facility-based setting versus a remotely coached/guided, home-based setting using telerehabilitation in physically inactive and cognitively intact people with MS who have walking dysfunction and mobility disability(N = 500). The primary outcome is walking speed. The secondary outcomes are walking endurance, disability status, and patient-reported outcomes of physical activity, walking impairment, fatigue, and quality of life. The components of the exercise program itself are similar between the groups and follow the Guidelines for Exercise in MS protocol. This includes a program manual, exercise prescription, exercise equipment, social-cognitive theory materials including newsletters, logs, and calendars, and one-on-one behavioral coaching by exercise specialists with background in MS. The main difference between groups is the coaching approach and setting for delivering the exercise training program. The outcomes will be collected by treatment-blinded assessors at baseline(week 0), mid-intervention(week 8), post-intervention(week 16), and follow-up(week 52).

DISCUSSION

The proposed study will provide evidence for the effectiveness of a novel, widely-scalable program for delivering exercise training in persons with MS who have walking dysfunction and mobility disability.

Integrated Cognitive and Neuromotor Rehabilitation in Multiple Sclerosis: A Pragmatic Study

Background: Few studies examined the effects of combined motor and cognitive rehabilitation in patients with multiple sclerosis (MS). The present prospective, multicenter, observational study aimed to determine the efficacy of an integrated cognitive and neuromotor rehabilitation program versus a traditional neuromotor training on walking, balance, cognition and emotional functioning in MS patients.

Methods: Sixty three MS patients were selected and assigned either to the Integrated Treatment Group (ITG; n = 32), receiving neuropsychological treatment (performed by ERICA software and paper–pencil tasks) complemented by conventional neuromotor rehabilitation, or to the Motor Treatment Group (n = 31) receiving neuromotor rehabilitation only. The intervention included two 60-min sessions per week for 24 weeks. At baseline and at end of the training all patients underwent a wide-range neuropsychological, psychological/emotional, and motor assessment.

Results: At baseline the two groups did not differ for demographic, neuropsychological, psychological/emotional, and motor features significantly. After rehabilitation, only ITG group significantly (p-corrected for False Discovery Rate) improved on test tapping spatial memory, attention and cognitive flexibility, as well as on scales assessing depression and motor performance (balance and gait). A regression analysis showed that neuropsychological and motor improvement was not related to improvements in fatigue and depression.

Conclusion: The present study demonstrated positive effects in emotional, motor, and cognitive aspects in MS patients who received an integrated cognitive and neuromotor training. Overall, results are supportive of interventions combining motor and cognitive training for MS.

Contributions of Ankle, Knee, Hip, and Trunk Muscle Function to Gait Performance in People With Multiple Sclerosis: A Cross-Sectional Analysis

BACKGROUND

The relative importance of lower extremity and trunk muscle function to gait in people with multiple sclerosis (MS) is unknown.

OBJECTIVE

This study aimed to investigate the association of lower extremity and trunk muscle function with gait performance in people who have MS and mild-to-moderate disability.

DESIGN

This was a cross-sectional, observational study.

METHODS

Participants were people who had an Expanded Disability Status Scale score of ≤ 5.5. Eleven lower extremity and trunk muscles were assessed using handheld dynamometry or endurance tests. Gait performance was assessed with the Timed 25-Foot (7.62 m) Walk (T25FW) and 6-Minute Walk Test (6MWT). Regression analysis was used to quantify the association between gait outcomes and muscle variables.

RESULTS

Seventy-two participants with MS and a mean Expanded Disability Status Scale score of 3.5 (SD = 1.14) were enrolled. Adjusted for age and sex, the multivariate model including hip abduction, ankle plantar flexion, trunk flexion, and knee flexion explained 57% of the adjusted variance in the T25FW; hip abduction, ankle plantar flexion, and trunk flexion explained 61% of the adjusted variance in the 6MWT. The strongest predictors were ankle plantar flexion endurance for the T25FW and hip abduction strength for the 6MWT: a 1-SD increase in ankle plantar flexion (15.2 heel-raise repetitions) was associated with a 0.33-second reduction in the T25WT (95% CI = - 0.71 to - 0.14 seconds); a 1-SD increase in normalized hip abduction strength (0.14 kg/body mass index) was associated with a 54.4-m increase in the 6MWT (28.99 to 79.81 m).

LIMITATIONS

Different measurement scales for independent variables were included because the muscle function assessment used either force or endurance.

CONCLUSIONS

For the major muscles in the lower extremity and trunk, hip abduction, ankle plantar flexion, trunk flexion, and knee flexion were the strongest predictors of gait performance.

Psychometric Properties of a Clinical Strength Assessment Protocol in People with Multiple Sclerosis

BACKGROUND

Strength training in people with multiple sclerosis (MS) is an important component of rehabilitation, but it can be challenging for clinicians to quantify strength accurately and reliably. This study investigated the psychometric properties of a clinical strength assessment protocol using handheld dynamometry and other objective, quantifiable tests for the lower extremities and trunk in people with MS.

METHODS

This study determined discriminant validity between 25 participants with MS and 25 controls and between participants with MS who had higher versus lower disability; test-retest reliability across 7 to 10 days; and response stability. The protocol included handheld dynamometry measurements of ankle dorsiflexion, knee flexion and extension; hip flexion, extension, abduction, and adduction; and trunk lateral flexion. Muscular endurance tests were used to measure trunk extension, trunk flexion, and ankle plantarflexion.

RESULTS

The protocol discriminated between participants with MS and controls for all muscles tested (P < .001-.003). The protocol also discriminated between low- and moderate-disability groups (P = .001-.046) for 80% of the muscles tested. Test-retest reliability intraclass correlation coefficients were high (0.81-0.97). Minimal detectable change as a percentage of the mean was 13% to 36% for 85% of muscles tested.

CONCLUSIONS

This study provides evidence for the discriminant validity, test-retest reliability, and response stability of a strength assessment protocol in people with MS. This protocol may be useful for tracking outcomes in people with MS for clinical investigations and practice.

The walking speed reserve in low disabled people with multiple sclerosis: Does it provide greater insight in detecting mobility deficits and risk of falling than preferred and fast walking speeds?

The extent of an increase from a preferred walking speed (PWS) to a fast walking speed (FWS) is defined as the walking speed reserve (WSR). The WSR is unique as it reflects an individual's ability to increase their walking speed on demand. The primary objective of this study was to examine whether the WSR was more advantageous than the PWS and FWS in terms of reflecting mobility deficits and risk of falling associated with multiple sclerosis (MS). The patient group included 235 people with MS (PwMS) (139 women) with a mean age of 43.6 (SD = 13.6) years. The WSR, PWS and FWS (m/s) were: 0.47 (SD = 0.29), 0.98 (SD = 0.28) and 1.45 (SD = 0.47), respectively. Significant correlation scores were found between the WSR and all clinical walking and balance outcome measures; Pearson's rho ranged from 0.240 to 0.517. However, stronger correlation scores were found between the PWS, FWS and all clinical walking and balance outcome measures with the Pearson's rho ranging from 0.415 to 0.797. In terms of fall status, non-significant differences were observed between the fallers (n = 133) and non-fallers' (n = 102) groups with respect to the WSR scores. We found that the PWS and FWS were more instructive measures for assessing mobility deficits and fall status in PwMS than the WSR. Nevertheless, we do not rule out the possibility that the WSR score may be a preferred predictor of other adverse events related to MS, such as lower limb muscle weakness, spasticity and aerobic capacity.

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

INTRODUCTION

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Self-efficacy and Walking Performance in Persons With Multiple Sclerosis

BACKGROUND AND PURPOSE

Impairment of walking function is a prevalent and burdensome feature of multiple sclerosis (MS), and represents a primary focus of rehabilitation research and clinical care. Research examining self-efficacy as a correlate of walking performance in MS is lacking; self-efficacy represents a theory-based, modifiable target of rehabilitation approaches for improving walking outcomes. This cross-sectional study examined the association between self-efficacy and walking performance in persons living with MS.

METHODS

The sample included 69 persons with MS who completed the Multiple Sclerosis Self-Efficacy (MSSE) Scale and Exercise Self-Efficacy (EXSE) Scale and undertook the Timed 25-Foot Walk (T25FW) and the 6-Minute Walk (6MW) tests. The data were analyzed using the Pearson product moment correlation coefficients and linear regression.

RESULTS

Correlation analysis indicated that function subscale scores on the MSSE correlated more strongly with T25FW (r = 0.55) than did the control subscale (r = 0.40) and EXSE (r = 0.38) scores, and both function (r = 0.67) and control (r = 0.53) subscale scores on the MSSE correlated more strongly with 6MW than did EXSE scores (r = 0.40). Linear regression analyses indicated that (1) function MSSE subscale, but not control subscale, explained significant variance in T25FW speed and 6MW distance and (2) function MSSE subscale, but not EXSE, explained significant variance in T25FW speed and 6MW distance.

DISCUSSION AND CONCLUSIONS

We provide the first evidence of an association between self-efficacy, particularly for functioning with MS, and objective walking performance in MS. Future research to replicate and extend these results can inform rehabilitation efforts that target improvement of walking performance in persons with MS.Digital Abstract available for more insights from the authors (see Slides, Supplemental Digital Content 1, http://links.lww.com/JNPT/A171).

Cognitive Motor Interference in Multiple Sclerosis: Insights From a Systematic Quantitative Review

OBJECTIVE

To synthesize the evidence for differences in cognitive motor interference (CMI) between persons with multiple sclerosis (MS) and those without MS by using systematic review and meta-analysis.

DATA SOURCES

EMBASE, PubMed, ScienceDirect, Scopus, SPORTDiscus, and Web of Science. Our focused literature search was informed by past systematic reviews of CMI during walking in MS.

STUDY SELECTION

The key terms searched included Multiple sclerosis and synonyms of motor function (eg, Gait disorders, Gait, Walking, Balance, or Fall) and motor and cognitive functions (eg, Cognitive motor interference or Thinking).

DATA EXTRACTION

From the 116 abstract-identified articles, 13 experimental studies were selected for the final analysis and were rated using the Quality Assessment of Diagnostic Accuracy Studies tool. A meta-analysis was performed for all considered outcomes.

DATA SYNTHESIS

The results yielded a small overall effect size (ES) of .08 (SE=.17; 95% confidence interval, -.25 to .40; z=.49; P>.05), which indicated a nonsignificant minimal difference in CMI between persons with MS and those without MS. The moderator analysis for motor task (mobility task: ES, .22; postural task: ES, -.11) was not significantly different between persons with MS and those without MS. The moderator analysis for cognitive task (verbal fluency task: ES, .66; mental tracking task: ES, .04; discrimination and decision-making task: ES, -.30) resulted in a significant difference in CMI between persons with MS and those without MS (P<.05).

CONCLUSIONS

We provide evidence that overall there is a minimal difference in CMI between persons with MS and those without MS.

Walking impairs cognitive performance among people with multiple sclerosis but not controls

People with multiple sclerosis (MS) complain of problems completing two tasks simultaneously; sometimes called 'dual-tasking' (DT). Previous research in DT among people with MS has focused on how adding a cognitive task interferes with gait and few have measured how adding a motor task could interfere with cognition. We aimed to determine the extent to which walking affects a concurrent working memory task in people with MS compared to healthy controls. We recruited MS participants (n=13) and controls (n=10) matched by age (±3years), education (±3years) and gender. Participants first completed the cognitive task (subtracting 7's from the previous number) and then again while walking on an instrumented walkway. Although there were no baseline differences in cognition or walking between MS participants and controls, MS participants demonstrated a 52% decrease in number of correct answers during DT (p<0.001). Mental Tracking Rate (% correct answers/min) correlated strongly with MS-related disability measured using the Expanded Disability Status Scale (EDSS; r(11)=-0.68, p<0.01). We propose that compromised mental tracking during walking could be related to limited neural resource capacity and could be a potentially useful outcome measure to detect ecologically valid dual tasking impairments.

Validity of the Timed Up and Go Test as a Measure of Functional Mobility in Persons With Multiple Sclerosis

OBJECTIVE

To examine the validity of the timed Up and Go (TUG) test as a measure of functional mobility in persons with multiple sclerosis (MS) by using a comprehensive framework based on construct validity (ie, convergent and divergent validity).

DESIGN

Cross-sectional study.

SETTING

Hospital setting.

PARTICIPANTS

Community-residing persons with MS (N=47).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Main outcome measures included the TUG test, timed 25-foot walk test, 6-minute walk test, Multiple Sclerosis Walking Scale-12, Late-Life Function and Disability Instrument, posturography evaluation, Activities-specific Balance Confidence scale, Symbol Digits Modalities Test, Expanded Disability Status Scale, and the number of steps taken per day.

RESULTS

The TUG test was strongly associated with other valid outcome measures of ambulatory mobility (Spearman rank correlation, rs=.71-.90) and disability status (rs=.80), moderately to strongly associated with balance confidence (rs=.66), and weakly associated with postural control (ie, balance) (rs=.31). The TUG test was moderately associated with cognitive processing speed (rs=.59), but not associated with other nonambulatory measures (ie, Late-Life Function and Disability Instrument-upper extremity function).

CONCLUSIONS

Our findings support the validity of the TUG test as a measure of functional mobility. This warrants its inclusion in patients' assessment alongside other valid measures of functional mobility in both clinical and research practice in persons with MS.

Thalamus volume and ambulation in multiple sclerosis: a cross-sectional study

Aim: This cross-sectional study examined if subcortical gray matter (SGM) structures accounted for differences in timed 25-foot walk (T25FW) speed between multiple sclerosis (MS) patients and controls. Methods: Subjects underwent brain MRI and completed the T25FW. Volumes of the thalamus, caudate, putamen and pallidum were calculated from 3D T1-weighted structural brain images. T2 lesion volume (T2LV) was determined by using a semiautomated edge detection contouring-thresholding technique. Results: There were differences in T25FW speed, SGM volumes and T2LV between MS and controls. T25FW speed was associated with SGM volumes and T2LV in MS and controls. Thalamic volume partially accounted for the difference in T25FW speed between the MS and controls. Conclusion: The reduction of thalamus volume is associated with compromised ambulation in MS patients.

Exercise Training and Cognitive Rehabilitation

The current review develops a rationale and framework for examining the independent and combined effects of exercise training and cognitive rehabilitation on walking and cognitive functions in persons with multiple sclerosis (MS). To do so, we first review evidence for improvements in walking and cognitive outcomes with exercise training and cognitive rehabilitation in MS. We then review evidence regarding cognitive–motor coupling and possible cross-modality transfer effects of exercise training and cognitive rehabilitation. We lastly present a macro-level framework for considering mechanisms that might explain improvements in walking and cognitive dysfunction with exercise and cognitive rehabilitation individually and combined in MS. We conclude that researchers should consider examining the effects of exercise training and cognitive rehabilitation on walking, cognition, and cognitive–motor interactions in MS and the possible physiological and central mechanisms for improving these functions.

Pallidal and caudate volumes correlate with walking function in multiple sclerosis

BACKGROUND

Walking dysfunction is common in multiple sclerosis (MS). The thalamus and basal ganglia seemingly have important associations with walking performance. The contribution of these subcortical gray matter (SGM) structures for walking dysfunction is poorly understood in MS.

PURPOSE

This study examined associations among volumes of the thalamus and basal ganglia with walking outcomes in MS.

METHOD

We enrolled 61 MS patients who underwent brain MRI and completed the 6-minute walk (6MW) and timed 25-foot walk (T25FW). Volumes of the thalamus, caudate, putamen, and pallidum as well as whole-brain white matter (WM) and gray matter (GM) were calculated from 3D T1-weighted structural brain images. We examined associations using bivariate correlations (r) and partial correlations (pr) that controlled for age, MS clinical course, and whole-brain WM and GM volumes. We further performed hierarchical linear regression (HLR) for identifying the strongest SGM correlate of walking performance.

RESULTS

The 6MW and T25FW correlated significantly with volumes of the thalamus (r's=.382 & .383), caudate (r's=.388 & .416), pallidum (r's=.457 & .457), and putamen (r's=.258 & .293) in bivariate correlations. The 6MW and T25FW remained significantly correlated with caudate (pr's=.243 & .312) and pallidum (pr's=.321 & .345) volumes in partial correlations. Pallidum volume was the strongest SGM correlate of 6MW (β=.39) and T25FW (β=.40) performance in HLR.

CONCLUSION

We provide novel evidence of possible SGM structures, particularly the pallidum and perhaps caudate, as correlates of walking performance in MS.