Day-to-day variability of maximum walking distance in MS patients can mislead to relevant changes in the Expanded Disability Status Scale (EDSS): average walking speed is a more constant parameter

Changes in real-world walking speed following 60-day bed-rest

The aim of this work was to explore whether real-world walking speed (RWS) would change as a consequence of 60-day bed-rest. The main hypothesis was that daily RWS would decrease after the bed-rest, with a subsequent recovery during the first days of re-ambulation. Moreover, an exploratory analysis was done in order to understand whether there is an agreement between the loss in RWS after bed-rest and the loss in the maximum oxygen uptake capacity (VO2max), or the loss in maximal vertical jump power (JUMP) respectively. Twenty-four subjects were randomly assigned to one of three groups: a continuous artificial gravity group, an intermittent artificial gravity group, or a control group. The fitted linear mixed effects model showed a significant decrease (p < 0.001) of RWS after the 60-day bed-rest and a subsequent increase (p < 0.001) of RWS during the 14-day recovery period in the study facility. No or little agreement was found between the loss in RWS and the loss in VO2max capacity or the loss in maximal vertical jumping power (RWS vs. VO2max: p = 0.81, RWS vs. JUMP: p = 0.173). Decreased RWS after bed-rest, with a follow-up recovery was observed for all three groups, regardless of the training intervention. This suggests that RWS, also in these settings, was able to reflect a de-conditioning and follow-up recovery process.

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

Background

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

Methods

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

Discussion

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

Inner Retinal Layer Changes Reflect Changes in Ambulation Score in Patients with Primary Progressive Multiple Sclerosis

The establishment of surrogate markers to detect disability progression in persons with multiple sclerosis (PwMS) is important to improve monitoring of clinical deterioration. Optical coherence tomography (OCT) could be such a tool. However, sufficient longitudinal data of retinal neuroaxonal degeneration as a marker of disease progression exist only for PwMS with a relapsing-remitting course (RRMS) so far. In contrast, longitudinal data of retinal layers in patients with primary-progressive MS (PPMS) are inconsistent, and the association of OCT parameters with ambulatory performance in PwMS has rarely been investigated. We aimed to investigate the relative annual rates of change in retinal layers in PwMS (RRMS and PPMS) compared with healthy controls (HC) using OCT and to evaluate their association with ambulatoryfunctionalscore (AS) worsening in PPMS. A retrospective analysis of a longitudinal OCT dataset of the retinal layers of PwMS and HC from two MS centers in Germany was performed. Walking ability was measured over a standardized distance of 500 m, and changes during the observation period were categorized using the AS and the expanded disability status scale (EDSS). 61 HC with 121 eyes and 119 PwMS (PPMS: 57 patients with 108 eyes; RRMS: 62 patients with 114 eyes) were included. The median follow-up time for PwMS was 3 years. The relative annual change of pRNFL (peripapillary retinal nerve fiber layer) and INL (inner nuclear layer) was significantly different in PwMS compared with HC. RRMS and PPMS subgroups did not differ in the annual atrophy rates. In patients with PPMS, worsening of the AS was significantly associated with increased thinning of the TMV (total macular volume), GCIP (ganglion cell and inner plexiform layer), and ONPL (outer nuclear and outer plexiform layer) (all p-value < 0.05, r > 0.30). For every -0.1% decrease in the TMV, GCIP, and ONPL, the risk of a deterioration in the AS increased by 31% (hazard ratio (HR): 1.309), 11% (HR: 1.112), and 16% (HR: 1.161), respectively. In addition, worsening EDSS in PPMS was significantly associated with the relative annual atrophy rates of pRNFL, TMV, and GCIP (all p-value < 0.05). Disability progression in PPMS can be measured using OCT, and increasing annual atrophy rates of the inner retinal layers are associated with worsening ambulation. OCT is a robust and side-effect-free imaging tool, making it suitable for routine monitoring of PwMS.

Smartphone accelerometry for quantifying core stability and developing exercise training progressions in people with multiple sclerosis

BACKGROUND

Core stability exercise programs have become popular in recent years for preserving balance and functional independence in people with multiple sclerosis (PwMS); however, their real impact is not well-known as the main intervention target (i.e., core stability) theoretically responsible for balance or functional improvements is not measured. The objective of this study was to test the reliability of accelerometers integrated into smartphones for quantifying core stability and developing exercise progressions in PwMS.

METHODS

Twenty participants with MS [age: 47.5±8.0 years; height: 1.62±0.07 m; mass: 63.4±10.9 kg; EDSS: 3.0 (1.5-6)] participated voluntarily in this study. CS was assessed in different variations of the front, side, and back bridges and bird-dog exercises by measuring the mean lumbopelvic acceleration in two testing sessions, separated by one week. Relative and absolute reliability of lumbopelvic acceleration of those exercise variations performed by more than 60% of the participants was analyzed by the intraclass correlation coefficient (ICC_3,1), and the standard error of measurement (SEM) and the minimal detectable change (MDC), respectively. Repeated measures ANOVAs were performed to detect a potential learning effect between test-retest assessments. Statistical significance was set at p < 0.05.

RESULTS

Reliability analyses revealed that good to excellent relative and absolute scores (0.85<ICC<0.96; 7.8%≤SEM≤19.2%; 21.6%≤MDC≤53.2%) for the mean lumbopelvic acceleration obtained during 10 of the 12 CS exercise variations performed by more than 60% of the participants. A non-significant between-session learning effect was detected in all the variables considered (all p values >0.05).

CONCLUSION

Smartphone accelerometry seems a low cost, portable and easy-to-use tool to objectively and reliably track core stability changes in PwMS through. However, in spite of the popularity of bridging and bird-dog exercises, only the short and long bridges and the three-point bird-dog positions proved feasible for most participants. Overall, this study provides useful information to evaluate and guide the prescription of core stability exercise programs in PwMS with mild-to-moderate impairment.

The moderating roles of self-efficacy and depression in dual-task walking in multiple sclerosis: A test of self-awareness theory

OBJECTIVE

Multiple sclerosis (MS) is a debilitating neurological disease associated with a variety of psychological, cognitive, and motoric symptoms. Walking is among the most important functions compromised by MS. Dual-task walking (DTW), an everyday activity in which people walk and engage in a concurrent, discrete task, has been assessed in MS, but little is known about how it relates to other MS symptoms. Self-awareness theory suggests that DTW may be a function of the interactions among psychological, cognitive, and motor processes.

METHOD

Cognitive testing, self-report assessments for depression and falls self-efficacy (FSE), and walk evaluations [DTW and single-task walk (STW)] were assessed in seventy-three people with MS in a clinical care setting. Specifically, we assessed whether psychological factors (depression and FSE) that alter subjective evaluations regarding one's abilities would moderate the relationships between physical and cognitive abilities and DTW performance.

RESULTS

DTW speed is related to diverse physical and cognitive predictors. In support of self-awareness theory, FSE moderated the relationship between STW and DTW speeds such that lower FSE attenuated the strength of the relationship between them. DTW costs - the change in speed normalized by STW speed - did not relate to cognitive and motor predictors. DTW costs did relate to depressive symptoms, and depressive symptoms moderated the effect of information processing on DTW costs.

CONCLUSIONS

Findings indicate that an interplay of physical ability and psychological factors - like depression and FSE - may enhance understanding of walking performance under complex, real-world, DTW contexts.

Criterion validity of muscle strain analyses of skeletal muscle function in patients with multiple sclerosis

BACKGROUND

Despite the wide range of existing performance measures to evaluate functional status of patients with multiple sclerosis, the heterogeneous nature of the disease hinders clinical characterization and monitoring of disease severity. Speckle tracking ultrasonography is a non-invasive technique to assess isolated muscle function by evaluating the contractile properties of muscle tissue, i.e. muscle strain. The aim of this study was to investigate whether muscle strain measured by speckle tracking ultrasonography could be a useful quantitative measure of muscle function in patients with multiple sclerosis. The criterion validity of muscle strain was compared to that of validated performance measures of upper and lower extremity function.

METHODS

This cross-sectional study used baseline data from an explorative observational cohort study (the MUST study). Participants recruited from a hospital outpatient MS clinic underwent speckle tracking ultrasonography of the biceps brachii, supraspinatus, and soleus muscles of the dominant side according to pre-defined submaximal isometric contractions. Participants also completed the Timed 25-Foot Walk Test, the Six Spot Step Test, the 2-minute walking test, the Nine-Hole Peg Test, the 12-item Multiple Sclerosis Walking Scale, and the Oxford Shoulder Score. Gaussian distribution was investigated by visual inspection of normal probability plots and the Shapiro-Wilk test. The Timed 25-Foot Walk Test and Nine-Hole Peg Test were selected as gold standards for function of the lower and upper extremities, respectively. Criterion validity was assessed using Spearman's rank-order correlation coefficient ρ (rho), comparing the muscle strain and performance measures against predefined gold standards. Differences in criterion validity were estimated using squared correlations on the Fischer's Z-scale, with non-parametric bootstrapping to obtain bias-corrected, accelerated bootstrap confidence intervals (95% BCa).

RESULTS

Criterion validity showed good to excellent correlations between the gold standard for lower extremity function and the 2-minute walking test and Six Spot Step Test, and a fair correlation to the 12-item Multiple Sclerosis Walking Scale. No significant correlation was found between the gold standard for upper extremity function and the performance measure. There were no significant correlations between the gold standards and muscle strain.

CONCLUSION

The absence of criterion validity for muscle strain alongside fair to strong criterion validity for the performance measures indicates that speckle tracking ultrasonography assessment of muscle strain is either invalid or evaluates other constructs of multiple sclerosis. Muscle strain assessed by speckle tracking ultrasonography cannot be recommended for the evaluation of treatment effects or disease progression in multiple sclerosis.

The effect of intermittent vs. continuous walking on distance to fatigue in persons with multiple sclerosis

PURPOSE

Previous studies provided evidence that persons with Multiple Sclerosis (pwMS) who walk intermittently experience less fatigue and walk longer distances than when walking continuously. However, total distance pwMS can walk in either condition is unknown. We examined time and distance to fatigability in pwMS comparing intermittent walking (IW) to continuous walking (CW).

MATERIALS AND METHODS

18 pwMS, with Expanded Disability Status Scale median of 4.75 [range = 2-6.5, IQR = 2.5] participated in this randomized crossover study. The IW condition consisted of alternating 30 s treadmill walking and 30 s seated rests. The CW condition consisted of treadmill walking without breaks. Treadmill speed (TS) was determined by an overground 2-min walk test. Walking fatigability was determined by participants walking on the treadmill, until gait fatigue was noted by patient or examiners. Total time and distance to gait fatigue, and subjective fatigue as measured by the Visual analog scale of fatigue were recorded.

RESULTS

Participants had significantly longer duration and distance to fatigue in the IW condition than the CW condition (ps ≤ 0.037). No difference in VASF scores between the two conditions were noted.

CONCLUSION

In this sample, IW allowed pwMS to perform a greater volume of walking and can be an option to improve walking endurance in this population.IMPLICATIONS FOR REHABILITATIONMultiple sclerosis (MS) is a disease that progressively impacts walking, resulting in a decrease in the maximum distance that a person with MS can walk.Intermittent walking has been shown to improve 6-min walk test performance in persons with MS (pwMS) compared to continuous walking, but its effects on longer and shorter walks is not known.The use of distance to fatigue should be considered a viable option for measuring walking fatigability in pwMS as it does not exclude persons based on their ability to complete a 6-min walk, nor would it be too easy for persons with pwMS with mild disability.By using distance to fatigue as an outcome measure, this study provides evidence that intermittent walking results in less fatigability regardless of walking ability.PwMS, regardless of their walking ability, can walk longer distances intermittently than continuously, suggesting that clinical treatment of walking fatigability in pwMS should utilize intermittent rather than continuous walking training.

The utility of wearable devices in assessing ambulatory impairments of people with multiple sclerosis in free-living conditions

BACKGROUND AND OBJECTIVES

Multiple sclerosis (MS) is a progressive inflammatory and neurodegenerative disease of the central nervous system affecting over 2.5 million people globally. In-clinic six-minute walk test (6MWT) is a widely used objective measure to evaluate the progression of MS. Yet, it has limitations such as the need for a clinical visit and a proper walkway. The widespread use of wearable devices capable of depicting patients' activity profiles has the potential to assess the level of MS-induced disability in free-living conditions.

METHODS

In this work, we extracted 96 features in different temporal granularities (from minute-level to day-level) from wearable data and explored their utility in estimating 6MWT scores in a European (Italy, Spain, and Denmark) MS cohort of 337 participants over an average of 10 months' duration. We combined these features with participants' demographics using three regression models including elastic net, gradient boosted trees and random forest. In addition, we quantified the individual feature's contribution using feature importance in these regression models, linear mixed-effects models, generalized estimating equations, and correlation-based feature selection (CFS).

RESULTS

The results showed promising estimation performance with R2 of 0.30, which was derived using random forest after CFS. This model was able to distinguish the participants with low disability from those with high disability. Furthermore, we observed that the minute-level (≤ 8 minutes) step count, particularly those capturing the upper end of the step count distribution, had a stronger association with 6MWT. The use of a walking aid was indicative of ambulatory function measured through 6MWT.

CONCLUSIONS

This study demonstrates the utility of wearables devices in assessing ambulatory impairments in people with MS in free-living conditions and provides a basis for future investigation into the clinical relevance.

Assessing visually guided reaching in people with multiple sclerosis with and without self-reported upper limb impairment

The ability to accurately complete goal-directed actions, such as reaching for a glass of water, requires coordination between sensory, cognitive and motor systems. When these systems are impaired, like in people with multiple sclerosis (PwMS), deficits in movement arise. To date, the characterization of upper limb performance in PwMS has typically been limited to results attained from self-reported questionnaires or clinical tools. Our aim was to characterize visually guided reaching performance in PwMS. Thirty-six participants (12 PwMS who reported upper limb impairment (MS-R), 12 PwMS who reported not experiencing upper limb impairment (MS-NR), and 12 age- and sex-matched control participants without MS (CTL)) reached to 8 targets in a virtual environment while seeing a visual representation of their hand in the form of a cursor on the screen. Reaches were completed with both the dominant and non-dominant hands. All participants were able to complete the visually guided reaching task, such that their hand landed on the target. However, PwMS showed noticeably more atypical reaching profiles when compared to control participants. In accordance with these observations, analyses of reaching performance revealed that the MS-R group was more variable with respect to the time it took to initiate and complete their movements compared to the CTL group. While performance of the MS-NR group did not differ significantly from either the CTL or MS-R groups, individuals in the MS-NR group were less consistent in their performance compared to the CTL group. Together these findings suggest that PwMS with and without self-reported upper limb impairment have deficits in the planning and/or control of their movements. We further argue that deficits observed during movement in PwMS who report upper limb impairment may arise due to participants compensating for impaired movement planning processes.

Test-Retest Reliability and Known-Groups Validity of Trunk Muscle Tests in People With Multiple Sclerosis: A Cross-Sectional, Case-Control Study

OBJECTIVE

Research on muscle performance testing reliability in people with multiple sclerosis (MS) has focused on limb performance while less is known about trunk strength and endurance. This work aims to 1) establish test-retest reliability of trunk flexion, lateral flexion, and extension strength tests, and plank, side bridge, and Biering-Sørensen endurance tests in people with MS and matched healthy controls (HCs); 2) analyze known-groups validity of these tests in people with MS and HCs; 3) to compare groups for side-to-side differences; and 4) to describe the relationships between trunk performance and functional mobility tests.

METHODS

Fifteen people with MS (median Expanded Disability Status Scale = 3) and 15 HCs underwent 2 trunk isometric strength and endurance testing sessions. Mobility was evaluated by Timed Up-and-Go test. Intraclass correlation coefficient, SEM, and minimal detectable change (MDC) were calculated. Between-group differences in trunk performance were tested using the t test for independent measures. Between-group differences in an asymmetry index were analyzed by independent t test. Bivariate correlations between trunk tests and mobility were also examined.

RESULTS

All trunk tests showed good-to-excellent relative reliability in both groups (intraclass correlation coefficient > 0.71). Regarding absolute reliability, strength tests were associated with low intersession variability in both groups (MDC: MS, 11.23%-36.45%; HCs, 26.60%-31.98%). Conversely, endurance tests showed higher variability scores in people with MS (MDC: MS, 69.55%-116.50%; HCs, 29.57%-54.40%). People with MS displayed significantly lower trunk performance. Likewise, the asymmetry index showed significantly higher scores in people with MS for endurance assessment but not in strength tests. Significant correlations were detected in people with MS between Timed Up-and-Go and several trunk tests (r = 0.63-0.70).

CONCLUSIONS

SEM and MDC scores revealed similar consistency and variability between groups for strength tests, whereas higher variability was observed for endurance tests in people with MS. Trunk strength tests are reliable and present discriminant validity to distinguish mildly disabled people with MS from HCs. Conversely, the high measurement error and variability of the endurance tests may hinder their application in intervention programs.

IMPACT

Determining the reliability and validity of the tests currently used to assess trunk function is of the greatest importance for people with MS (who show not only impaired trunk function but also wide fluctuations in performance), as it requires consistent and accurate measurements that are sensitive enough to detect minimal changes induced by rehabilitation.

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

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

Assessment of Multiple Sclerosis Disability Progression Using a Wearable Biosensor: A Pilot Study

Background: The evaluation of walking activity of people with multiple sclerosis (pwMS) is desirable. We evaluate the power of the correlation of motor parameters detected by the accelerometer in the Samsung Gear S2 smartwatch with multiple sclerosis (MS) disability measures and patient reported outcomes (PROs). Methods: We enrolled 25 relapsing remitting MS patients. We assessed disability with the expanded disability status scale, two-minute walking test (2MWT), timed 25-foot walk test (T25FWT), and nine-hole peg test. We collected PROs measuring fatigue, ambulatory ability, depression, quality of life, and bladder/bowel function. Participants were asked to wear the accelerometer for a period of 30 days. Results: The Spearman’s rank correlation coefficient showed a moderate negative correlation between the patient-determined disease steps (PDDS) score with the mean steps/day, a strong negative correlation between the PDDS score with the maximum number of daily steps (MNDS) and a moderate negative correlation between the fatigue severity scale score and MNDS. A moderate negative correlation between MNDS and the 2MWT and a moderate negative correlation between MNDS and the T25FW was found. Conclusion: Our results suggest that motor parameters derived from the accelerometer could be a reliable measure of motor disability in pwMS.

Safety, Feasibility, and Efficacy of an Eccentric Exercise Intervention in People with Multiple Sclerosis with Ankle Contractures

Background

The primary aim of this study was to investigate the safety and feasibility of an eccentric exercise program for people with multiple sclerosis (MS) who have ankle contractures, ie, reduced ankle range of motion (ROM). Secondary aims were to explore the efficacy of this eccentric exercise on ankle joint ROM and functional mobility.

Methods

Five adults with MS with ankle contractures (three women and two men; mean ± SD age, 50.8 ± 9.4; MS duration, 7.6 ± 5.6 years) completed two eccentric exercise training sessions (10-45 minutes) per week for 12 weeks. The training involved walking backward downhill on an inclined treadmill (gradient, 10°-14°) at a self-selected pace. The intervention was assessed for safety (adverse events), feasibility (recruitment rates, adherence rates, enjoyment levels, difficulty, and discomfort), and clinical outcomes, including passive/active ankle ROM and distance walked in 6 minutes.

Results

There were no adverse events during or after the eccentric exercise training. There was a 100% adherence rate. All participants enjoyed the training and experienced low levels of muscle soreness/discomfort. The training program improved passive/active ankle ROM in all participants; however, improvements did not translate to improvements in walking for all participants.

Conclusions

Walking backward and downhill is a safe and feasible training modality for people with MS with ankle contractures. Clinical outcomes (greater passive/active ankle ROM) after this eccentric exercise training were evident. However, translation to clinically meaningful changes in walking function requires further examination.

Simple Smartphone-Based Assessment of Gait Characteristics in Parkinson Disease: Validation Study

Background

Parkinson disease (PD) is a common movement disorder. Patients with PD have multiple gait impairments that result in an increased risk of falls and diminished quality of life. Therefore, gait measurement is important for the management of PD.

Objective

We previously developed a smartphone-based dual-task gait assessment that was validated in healthy adults. The aim of this study was to test the validity of this gait assessment in people with PD, and to examine the association between app-derived gait metrics and the clinical and functional characteristics of PD.

Methods

Fifty-two participants with clinically diagnosed PD completed assessments of walking, Movement Disorder Society Unified Parkinson Disease Rating Scale III (UPDRS III), Montreal Cognitive Assessment (MoCA), Hamilton Anxiety (HAM-A), and Hamilton Depression (HAM-D) rating scale tests. Participants followed multimedia instructions provided by the app to complete two 20-meter trials each of walking normally (single task) and walking while performing a serial subtraction dual task (dual task). Gait data were simultaneously collected with the app and gold-standard wearable motion sensors. Stride times and stride time variability were derived from the acceleration and angular velocity signal acquired from the internal motion sensor of the phone and from the wearable sensor system.

Results

High correlations were observed between the stride time and stride time variability derived from the app and from the gold-standard system (r=0.98-0.99, P<.001), revealing excellent validity of the app-based gait assessment in PD. Compared with those from the single-task condition, the stride time (F_1,103=14.1, P<.001) and stride time variability (F_1,103=6.8, P=.008) in the dual-task condition were significantly greater. Participants who walked with greater stride time variability exhibited a greater UPDRS III total score (single task: β=.39, P<.001; dual task: β=.37, P=.01), HAM-A (single-task: β=.49, P=.007; dual-task: β=.48, P=.009), and HAM-D (single task: β=.44, P=.01; dual task: β=.49, P=.009). Moreover, those with greater dual-task stride time variability (β=.48, P=.001) or dual-task cost of stride time variability (β=.44, P=.004) exhibited lower MoCA scores.

Conclusions

A smartphone-based gait assessment can be used to provide meaningful metrics of single- and dual-task gait that are associated with disease severity and functional outcomes in individuals with PD.

Potential of Timed 25-Foot Walk Values in Predicting Maximum Walking Distance in Persons with Multiple Sclerosis

Background

Expanded Disability Status Scale (EDSS) scores of 4.0 or greater are determined primarily by maximum walking distance (MWD). Estimation of MWD by persons with multiple sclerosis (MS) is often used due to the impracticality of formally walking a person with MS in a clinic setting. Previous studies have demonstrated discrepancies between estimated and actual MWDs. Whether Timed 25-Foot Walk test (T25FW) values can be used to predict MWD is currently unknown. This study aimed to determine whether T25FW time is predictive of MWD in persons with MS.

Methods

This study is a post hoc analysis of a previously described prospective cohort study. Persons with MS with an EDSS score of 3.5 to 5.5 were included. The participant's T25FW values and MWD were measured.

Results

Of the 38 adult participants (mean age, 50.8 years; 27 women [71%]), 24 (63%) had relapsing-remitting MS. The median EDSS score was 4.5 (range, 3.5-5.5). The T25FW times were divided into seven categories (<5.0, 5.0-5.9, 6.0-6.9, 7.0-7.9, 8.0-8.9, 9.0-9.9, and ≥10.0 seconds). The MWDs were divided into corresponding EDSS score categories: ≥500, 300-499, 200-299, 100-199, and ≤99 m. Ordinal logistic regression, when controlled for age, found the T25FW categories to be predictive of EDSS score (χ² = 17.630, df = 7, P = .014).

Conclusions

The T25FW value may be used as a surrogate estimate of MWD. Further studies are needed to confirm the reliability of the T25FW in predicting MWD.

Effects of Intensive Voice Treatment (The Lee Silverman Voice Treatment [LSVT LOUD]) in Subjects With Multiple Sclerosis: A Pilot Study

AIM

The rehabilitation of voice disorders is an unmet need in multiple sclerosis (MS). The Lee Silverman Voice Treatment (LSVT LOUD) is a well-documented and effective speech treatment, developed to treat voice disorders in Parkinson Disease. The purpose of the present study was to examine the viability of applying the LSVT LOUD to individuals with MS and verify short- and long-term improvements in acoustic and perceptual voice parameters.

METHODS

A single subject design was performed in a consecutive sample of 8 subjects with MS. The subjects' voice was recorded with PRAAT software for 5 days at baseline during the 16  treatment sessions, and at follow-up (FU) 6/12 months later. PRAAT provided data on sustained /a/ (SPL/a/) voice intensity and maximum phonation time (MPT/a/) of sustained /a/, and on functional sentences voice intensity. In addition, self-assessment questionnaire Voice Handicap Index, the perceptual GIRBAS scale and intensity of monologue were collected at first day of baseline, post-treatment and at FU. In the treatment phase each subject received treatment according to LSVT LOUD protocol. Visual analysis calculated for daily acoustic variables was used to determine baseline stability and analyse changes following treatment. The Wilcoxon test was used to assess statistically significant differences between baseline and post treatment.

RESULTS

All participants completed the LSVT LOUD programme; one participant dropped out at FU. Improvements in acoustic analysis were found: SPL/a/ improved on average (± standard deviation) 11.64 ± 4.19 dB with 7 subjects showing statistically significant improvement (P < 0.05); MPT/a/ improved on average 1.2 ± 1.53seconds, while intensity of functional sentences improved on average 8.11 ± 3.46  dB with 4 and 5 subjects showed statistically significant improvement, respectively. Intensity of monologue improved 14.90 ± 3.33 dB. Acoustic values are maintained or increased at FU respect to baseline. All subjects improved perceptual ratings at Voice Handicap Index and results were maintained at FU. These changes were associated with improvements on five parameters on the GIRBAS scale at post-treatment, however no further improvement were observed at FU.

CONCLUSION

Intensive LSVT LOUD treatment is a viable approach to treat hypophonia in MS. LSVT LOUD improved both quantitative-instrumental and perceptive-subjective assessments. Randomised controlled trials are needed to provide a firm support on the effectiveness of LSVT LOUD in MS.

Smartphone Accelerometry: A Smart and Reliable Measurement of Real-Life Physical Activity in Multiple Sclerosis and Healthy Individuals

Background: Mobility impairment is common in persons with multiple sclerosis (pwMS) and can be assessed with clinical tests and surveys that have restricted ecological validity. Commercial research-based accelerometers are considered to be more valuable as they measure real-life mobility. Smartphone accelerometry might be an easily accessible alternative.

Objective: To explore smartphone accelerometry in comparison to clinical tests, surveys, and a wrist-worn ActiGraph in pwMS and controls.

Methods: Sixty-seven pwMS and 70 matched controls underwent mobility tests and surveys. Real-life data were collected with a smartphone and an ActiGraph over 7 days. We explored different smartphone metrics in a technical validation course and computed afterward correlation between ActiGraph (steps per minute), smartphone accelerometry (variance of vector magnitude), clinical tests, and surveys. We also determined the ability to separate between patients and controls as well as between different disability groups.

Results: Based on the technical validation, we found the variance of the vector magnitude as a reliable estimate to discriminate wear time and no wear-time of the smartphone. Due to a further association with different activity levels, it was selected for real-life analyses. In the cross-sectional study, ActiGraph correlated moderately (r = 0.43, p < 0.05) with the smartphone but less with clinical tests (rho between |0.211| and |0.337|). Smartphone data showed stronger correlations with age (rho = −0.487) and clinical tests (rho between |0.565| and |0.605|). ActiGraph only differed between pwMS and controls (p < 0.001) but not between disability groups. At the same time, the smartphone showed differences between pwMS and controls, between RRMS and PP-/SPMS, and between participants with/without ambulatory impairment (all p < 0.001).

Conclusions: Smartphone accelerometry provides better estimates of mobility and disability than a wrist-worn standard accelerometer in a free-living context for both controls and pwMS. Given the fact that no additional device is needed, smartphone accelerometry might be a convenient outcome of real-life ambulation in healthy individuals and chronic diseases such as MS.

Sempere Á, Vera-Garcia FJ, Barbado D. Understanding the Deterioration of Gait, Postural Control, Lower Limb Strength and Perceived Fatigue Across the Disability Spectrum of People with Multiple Sclerosis

Disability progression is a prominent feature of multiple sclerosis (MS). However, little is known about the extent to which physical condition parameters and perceived fatigue evolve during the disease. We analyzed how strength, balance, core stability and perceived fatigue differ among different cohorts of people with MS (PwMS) with different disability degrees and how these contribute to patients' gait speed and functional mobility. Sixty-three PwMS divided into three groups according to the "Expanded Disability Status Scale" (MS1: EDSS ≤ 1.5; MS2: 2 ≤ EDSS ≤ 3.5; MS3: 4 ≤ EDSS ≤ 6) and 22 healthy controls (HC) participated in this study. MS1 showed lower balance and hip strength compared to HC. MS2 showed lower balance, core stability, gait speed, and functional mobility than MS1. MS3 showed lower gait speed, functional mobility, balance, and knee flexion strength than MS2. No between-group differences were observed in perceived fatigue. Relative weight analysis showed that strength, balance and core stability explained 60%-70% of the variance in gait speed and functional mobility. The decline of each parameter did not evolve at the same rate across the different stages of the disease, being knee flexion strength and balance the most influential factors in the disability progression. Overall, these results provide useful information to guide exercise prescription at different stages of MS.

Ecological Momentary Assessment of Head Motion: Toward Normative Data of Head Stabilization

Head stabilization is fundamental for balance during locomotion but can be impaired in elderly or diseased populations. Previous studies have identified several parameters of head stability with possible diagnostic value in a laboratory setting. Recently, the ecological validity of measures obtained in such controlled contexts has been called into question. The aim of this study was to investigate the ecological validity of previously described parameters of head stabilization in a real-world setting. Ten healthy subjects participated in the study. Head and trunk movements of each subject were recorded with inertial measurement units (IMUs) for a period of at least 10 h. Periods of locomotion were extracted from the measurements and predominant frequencies, root mean squares (RMSs) and bout lengths were estimated. As parameters of head stabilization, attenuation coefficients (ACs), harmonic ratios (HRs), coherences, and phase differences were computed. Predominant frequencies were distributed tightly around 2 Hz and ACs, HRs, and coherences exhibited the highest values in this frequency range. All head stability parameters exhibited characteristics consistent with previous reports, although higher variances were observed. These results suggest that head stabilization is tuned to the 2 Hz fundamental frequency of locomotion and that previously described measures of head stability could generalize to a real-world setting. This is the first study to address the ecological validity of these measures, highlighting the potential use of head stability parameters as diagnostic tools or outcome measures for clinical trials. The low cost and ease of use of the IMU technology used in this study could additionally be of benefit for a clinical application.

Optical Boundaries for LED-Based Indoor Positioning System

Overlap of footprints of light emitting diodes (LEDs) increases the positioning accuracy of wearable LED indoor positioning systems (IPS) but such an approach assumes that the footprint boundaries are defined. In this work, we develop a mathematical model for defining the footprint boundaries of an LED in terms of a threshold angle instead of the conventional half or full angle. To show the effect of the threshold angle, we compare how overlaps and receiver tilts affect the performance of an LED-based IPS when the optical boundary is defined at the threshold angle and at the full angle. Using experimental measurements, simulations, and theoretical analysis, the effect of the defined threshold angle is estimated. The results show that the positional time when using the newly defined threshold angle is 12 times shorter than the time when the full angle is used. When the effect of tilt is considered, the threshold angle time is 22 times shorter than the full angle positioning time. Regarding accuracy, it is shown in this work that a positioning error as low as 230 mm can be obtained. Consequently, while the IPS gives a very low positioning error, a defined threshold angle reduces delays in an overlap-based LED IPS.

Can we trust self-reported walking distance when determining EDSS scores in patients with multiple sclerosis? The Danish MS hospitals rehabilitation study

Background:

In multiple sclerosis (MS), the Expanded Disability Status Scale (EDSS) reflects disease severity. Although parts of the EDSS are dependent on actual walking distance, self-reported statements are often applied.

Objectives:

The purpose of the present study was, therefore, to compare self-reported walking distance to actual walking distance to outline how this influences EDSS scoring.

Methods:

MS patients with EDSS 4.0–7.5 ( n = 273) were included from the Danish MS hospitals rehabilitation study ( n = 427). All patients subjectively classified their maximal walking distance according to one of seven categories (>500; 300–499; 200–299; 100–199; 20–99; 5–19; 0–4 m). Subsequently, actual maximal walking distance was assessed and EDSS was determined from both self-reported walking distance (EDSSself-report) and actual walking distance (EDSSactual).

Results:

In 145 patients (53%), self-reported walking distance was misclassified when compared to the actual walking distance. Misclassification was more frequent in patients using walking aids (64% vs. 44%, p < 0.05) and in patients with primary progressive MS (69%, p < 0.05). Misclassification of walking distance corresponded to incorrect EDSS scores (EDSSself-report vs EDSSactual) of ⩾0.5 point in 24%.

Conclusion:

In MS patients with EDSS 4.0–7.5, 53% misclassified their walking distance yielding incorrect EDSS scores in 24%. Therefore, correct EDSS determination must be based on measurement of actual walking distance.

Remote Monitoring in the Home Validates Clinical Gait Measures for Multiple Sclerosis

Background: The timed 25-foot walk (T25FW) is widely used as a clinic performance measure, but has yet to be directly validated against gait speed in the home environment. Objectives: To develop an accurate method for remote assessment of walking speed and to test how predictive the clinic T25FW is for real-life walking. Methods: An AX3-Axivity tri-axial accelerometer was positioned on 32 MS patients (Expanded Disability Status Scale [EDSS] 0-6) in the clinic, who subsequently wore it at home for up to 7 days. Gait speed was calculated from these data using both a model developed with healthy volunteers and individually personalized models generated from a machine learning algorithm. Results: The healthy volunteer model predicted gait speed poorly for more disabled people with MS. However, the accuracy of individually personalized models was high regardless of disability (R-value = 0.98, p-value = 1.85 × 10-22). With the latter, we confirmed that the clinic T25FW is strongly predictive of the maximum sustained gait speed in the home environment (R-value = 0.89, p-value = 4.34 × 10-8). Conclusion: Remote gait monitoring with individually personalized models is accurate for patients with MS. Using these models, we have directly validated the clinical meaningfulness (i.e., predictiveness) of the clinic T25FW for the first time.

What We Learned from The History of Multiple Sclerosis Measurement: Expanded Disability Status Scale

Multiple Sclerosis (MS) is often seen in young adults and known to cause both physical and cognitive disability, and it is quite important to make an objective assessment of the physical-cognitive disability status of the patients. The first scale that assesses the physical disability in MS cases, the Disability Status Scale (DSS) elaborated in 1983 and transformed into the Expanded DSS (EDSS). It has been in use since 1983 without much change, which is one of its most significant advantages. It includes all functional systems (although with some shortcomings) that may be affected in MS and reflects the clinical status as a number, which is quite valuable. Although there may be differences between EDSS practitioners, it has been in use for more than 30 years and it can objectively display the difference between a patient's clinical picture 20 years ago and today, which can be said for only a small number of scales. This shows the importance of using the same scale for diseases that require long-term monitoring such as MS. In conclusion; it is a consensus that EDSS will not undergo major changes so that its greatest advantage can be preserved. Also, the consensus in the available literature is that EDSS will never lose its value.

Validity and Reliability of Four Clinical Gait Measures in Patients with Multiple Sclerosis

BACKGROUND

The gold standards for assessing ambulation are the Expanded Disability Status Scale (EDSS) and the Timed 25-Foot Walk (T25FW) test. In relation with these measures, we assessed the reliability and validity of four clinical gait measures: the Timed Up and Go (TUG) test, the Dynamic Gait Index (DGI), the 2-Minute Walk Test (2MWT), and the 6-Minute Walk Test (6MWT). Patient self-report of gait was also assessed using the 12-item Multiple Sclerosis Walking Scale (MSWS-12).

METHODS

Individuals 20 years or older with a diagnosis of multiple sclerosis (MS) and an EDSS score of 2.0 to 6.5 completed the MSWS-12, T25FW test, TUG test, DGI, 2MWT, and 6MWT. All the tests were repeated 2 weeks later at the same time of day to establish their reliability and concurrent validity. Predictive validity was established using the EDSS.

RESULTS

Forty-two patients with MS were included. All measures showed high test-retest reliability. The TUG test, 2MWT, and 6MWT were significantly correlated with the T25FW test (Spearman ρ = -0.902, -0.919, and -0.905, respectively). The EDSS was also significantly correlated with all the walking tests. The MSWS-12 demonstrated the highest correlation to the EDSS (ρ = 0.788).

CONCLUSIONS

The TUG test, the DGI, the 2MWT, and the 6MWT exhibited strong psychometric properties and were found to be significant predictors of the EDSS score. Use of these tests to prospectively monitor the effects of medical and rehabilitation treatment should be considered in the comprehensive care of patients with MS.

Instrumented balance and walking assessments in persons with multiple sclerosis show strong test-retest reliability

BACKGROUND

There is a need for objective movement assessment for clinical research trials aimed at improving gait and balance in persons with multiple sclerosis (PwMS). Wireless inertial sensors can accurately measure numerous walking and balance parameters but these measures require evaluation of reliability in PwMS. The current study determined the test-retest reliability of wireless inertial sensor measures obtained during an instrumented standing balance test and an instrumented Timed Up and Go test in PwMS.

METHODS

Fifteen PwMS and 15 healthy control subjects (HC) performed an instrumented standing balance and instrumented Timed Up and Go (TUG) test on two separate days. Ten instrumented standing balance measures and 18 instrumented TUG measures were computed from the wireless sensor data. Intraclass correlation coefficients (ICC) were calculated to determine test-retest reliability of all instrumented standing balance and instrumented TUG measures. Correlations were evaluated between the instrumented standing balance and instrumented TUG measures and self-reported walking and balance performance, fall history, and clinical disability.

RESULTS

For both groups, ICCs for instrumented standing balance measures were best for spatio-temporal measures, while frequency measures were less reliable. All instrumented TUG measures exhibited good to excellent (ICCs > 0.60) test-retest reliability in PwMS and in HC. There were no correlations between self-report walking and balance scores and instrumented TUG or instrumented standing balance metrics, but there were correlations between instrumented TUG and instrumented standing balance metrics and fall history and clinical disability status.

CONCLUSIONS

Measures from the instrumented standing balance and instrumented TUG tests exhibit good to excellent reliability, demonstrating their potential as objective assessments for clinical trials. A subset of the most reliable measures is recommended for measuring walking and balance in clinical settings.

The EDSS-Plus, an improved endpoint for disability progression in secondary progressive multiple sclerosis

BACKGROUND

The Expanded Disability Status Scale (EDSS) has wide scientific and regulatory precedent but limited ability to detect clinically relevant disability progression in secondary progressive multiple sclerosis (SPMS) patients, partly due to a lack of meaningful measurement of short-distance ambulatory and upper-extremity function.

OBJECTIVE

To present a rationale for a composite endpoint adding the timed 25-foot walk (T25FW) and 9-Hole Peg Test (9HPT) to EDSS for SPMS disability progression assessment.

METHODS

Using the International Multiple Sclerosis Secondary Progressive Avonex Clinical Trial (IMPACT) placebo arm ( n = 215) data, we analyzed disability progression using a novel progression endpoint, "EDSS-Plus," defined as progression on ⩾1 of 3 components (EDSS, T25FW, and/or 9HPT) confirmed ⩾24 weeks apart and with a ⩾20% minimum threshold change for T25FW and 9HPT.

RESULTS

Over 2 years, subjects classified as T25FW, 9HPT (dominant hand), or 9HPT (non-dominant hand) progressors worsened on average by 103.4%, 69.0%, and 59.2%, respectively, while non-progressors' times remained largely unchanged. Using EDSS-Plus, 59.5% of the patients had 24-week confirmed disability progression versus 24.7% (EDSS), 41.9% (T25FW), and 34.4% (9HPT (either hand)) on each component alone.

CONCLUSION

The 24-week confirmed minimum worsening of ⩾20% for T25FW and 9HPT clearly separates SPMS progressors from non-progressors. We propose that EDSS-Plus may represent an improved endpoint to identify SPMS disability progression.

Effects of Intermittent Versus Continuous Walking on Distance Walked and Fatigue in Persons With Multiple Sclerosis: A Randomized Crossover Trial

BACKGROUND AND PURPOSE

Fatigue is a common, disabling symptom experienced by persons with multiple sclerosis (MS). Evidence shows that intermittent exercise is associated in improved performance and negligible fatigue. The purpose of this study was to examine whether subjects with MS walk greater distances with less fatigue under intermittent (INT) or continuous (CONT) walking condition.

METHODS

Twenty-seven subjects with MS (median Extended Disability Severity Scale 3.5, interquartile range 1.6) walked in the CONT (ie, 6 uninterrupted minutes) and INT (ie, three 2-minute walking bouts) conditions in a randomized crossover. Distance was measured for the entire 6-minute walking period and each 2-minute increment. Fatigue was measured as the difference in a visual analog scale of fatigue (ΔVAS-F) immediately preceding and following each trial.

RESULTS

Participants walked greater distances in the INT condition compared to the CONT condition (P = 0.005). There was a significant interaction of walking condition and time (P < 0.001), indicating that the distances walked in the INT condition changed across time. ΔVAS-F was significantly lower in the INT condition than in the CONT condition (P = 0.036).

DISCUSSION AND CONCLUSION

Subjects with MS walked farther, and with less fatigue, when walking intermittently rather than continuously. Persons with MS may be able to tolerate a greater dose of walking training if the walking bouts are intermittent. Further study to determine the benefits of a walking exercise program using intermittent walking is recommended.Video Abstract available for additional insights from the authors (Supplemental Digital Content 1, http://links.lww.com/JNPT/A103).

Treatment Optimization in Multiple Sclerosis

The treatment of multiple sclerosis has finally become possible with the advent of the current disease-modifying therapies (DMTs) that have had a significant impact on those living with this disease. Though demonstrating clear efficacy on a number of short-term outcome measures, unfortunately, these agents are not “cures” and many patients with multiple sclerosis continue to experience disease activity in spite of treatment. Clinicians are becoming more comfortable initiating therapy with DMTs, but it is now important to focus attention on monitoring the results of the chosen therapy and deciding whether or not a patient is responding well to treatment. At present, however, clinicians lack criteria for defining optimal versus suboptimal responses to DMTs as well as evidence-based guidelines on how to improve treatment outcomes. Using a recently published model as a framework, The Canadian Multiple Sclerosis Working Group developed practical recommendations on how neurologists can assess the status of patients on DMTs and decide when it may be necessary to modify treatment in order to optimize outcomes. The Canadian Multiple Sclerosis Working Group's recommendations are based on monitoring relapses, neurological progression and MRI activity. Other possible causes of suboptimal treatment responses or treatment failure are also considered.

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.

Spatial and temporal characteristics of gait as outcome measures in multiple sclerosis (EDSS 0 to 6.5)

BACKGROUND

Gait impairment represents one of the most common and disabling symptom of multiple sclerosis. Quantification of the gait is an important aspect of clinical trials. In order to identify which temporal or spatial parameters of gait could be used as outcome measures in interventional studies of patients with different levels of disability, we evaluated characteristics of these parameters in MS patients across the whole spectrum of mobility from EDSS 0 to 6.5.

METHODS

This is a cross-sectional study of spatial and temporal parameters of gait at self selected speed and at fast speed of walking in 284 patients with multiple sclerosis (108 men, mean age 38 years ± SD 10.8 years, range 18-64) divided into seven levels of disability (EDSS 0 to 1.5, EDSS 2.0 to 2.5, EDSS 3.0 to 3.5, EDSS 4.0 to 4.5, EDSS 5.0 to 5.5, EDSS 6.0, EDSS 6.5).

RESULTS

The velocity of gait decreases with increasing EDSS levels. Hovewer, the spatio-temporal parameters of gait that are involved in this process differ across the EDSS levels. The step length is decreased at higher EDSS levels up to the EDSS 6.0, but was not different between EDSS 6.0 and 6.5. The step time is significantly longer at EDSS 6.0 and 6.5, while the step length remains the same at those levels. The increase in percentage of double support time becomes statistically significant at EDSS 3.0-3.5 and continues to increase until EDSS 6.5. Variability of step time, step length or step width did not show significant difference between studied EDSS levels.

CONCLUSIONS

There is no single spatio-temporal parameter of gait (other than velocity of gait) that would show significant differences among all levels of EDSS. The step length reflects shortening of steps at lower EDSS levels (2.0 to 6.0), and percentage of double support time better reflects changes at higher EDSS levels 3.0 - 6.5. Gait variability is not associated with disability in MS and therefore would not be a suitable outcome measure. These observations have to be considered when designing gait experiments with temporal and spatial parameters of gait as outcomes.

A 3meter Timed Tandem Walk is an early marker of motor and cerebellar impairment in fully ambulatory MS patients

BACKGROUND

Mobility assessment in Multiple Sclerosis (MS) is crucial for trials and individual patient counseling. Up to now, standard tests as the Timed 25-Foot Walk (T25FW) are restricted by floor effects in mildly disabled patients. The 3-meter Timed Tandem Walk (TTW) as a possibly more sensitive measure has not been investigated yet.

OBJECTIVE

To investigate sensitivity and specificity of the TTW and T25FW to detect mild clinical impairment in a large cohort of MS patients.

METHODS

We extracted T25FW, TTW and EDSS from our UMC patient database (2009-2012). After randomization into an explorative (n = 497) and validation (n = 228) cohort, we calculated change rates and performed ROC analyses of gait tests and EDSS including Functional System Scores.

RESULTS

Between disability stages of EDSS 0-2.5 and EDSS 3.0-4.0, the mean TTW difference was 4s (T25FW = 0.9s). The accuracy to separate between EDSS groups was moderate but identical for both tests (ROC-AUC T25FW = 0.79, TTW = 0.80, p = 0.4). TTW had a higher sensitivity and specificity to differentiate between asymptomatic and symptomatic patients concerning FS motor/cerebellar scores (ROC-AUC T25FW = 0.71, TTW = 0.75, p < 0.05). All hypotheses could be validated in the second cohort.

CONCLUSION

A 3-m Timed Tandem Walk is a standardized test that is easy to implement to detect impairment of the motor or cerebellar system in fully ambulatory MS patients. Based on the complex-task character, TTW is a potential new outcome measure for MS mobility in mildly disabled patients and can act as easily accessible and significant additional information in patient counseling.

A passive exoskeleton can push your life up: application on multiple sclerosis patients

In the present study, we report the benefits of a passive and fully articulated exoskeleton on multiple sclerosis patients by means of behavioral and electrophysiological measures, paying particular attention to the prefrontal cortex activity. Multiple sclerosis is a neurological condition characterized by lesions of the myelin sheaths that encapsulate the neurons of the brain, spine and optic nerve, and it causes transient or progressive symptoms and impairments in gait and posture. Up to 50% of multiple sclerosis patients require walking aids and 10% are wheelchair-bound 15 years following the initial diagnosis. We tested the ability of a new orthosis, the “Human Body Posturizer”, designed to improve the structural and functional symmetry of the body through proprioception, in multiple sclerosis patients. We observed that a single Human Body Posturizer application improved mobility, ambulation and response accuracy, in all of the tested patients. Most importantly, we associated these clinical observations and behavioral effects to changes in brain activity, particularly in the prefrontal cortex.

Cross-cultural adaptation and validation of the 12-item Multiple Sclerosis Walking Scale (MSWS-12) for the Brazilian population

Gait impairment is reported by 85% of patients with multiple sclerosis (MS) as main complaint. In 2003, Hobart et al. developed a scale for walking known as The 12-item Multiple Sclerosis Walking Scale (MSWS-12), which combines the perspectives of patients with psychometric methods.

OBJECTIVE

This study aimed to cross-culturally adapt and validate the MSWS-12 for the Brazilian population with MS.

METHODS

This study included 116 individuals diagnosed with MS, in accordance with McDonald's criteria. The steps of the adaptation process included translation, back-translation, review by an expert committee and pretesting. A test and retest of MSWS-12/BR was made for validation, with comparison with another scale (MSIS-29/BR) and another test (T25FW).

RESULTS

The Brazilian version of MSWS-12/BR was shown to be similar to the original. The results indicate that MSWS-12/BR is a reliable and reproducible scale.

CONCLUSIONS

MSWS-12/BR has been adapted and validated, and it is a reliable tool for the Brazilian population.

EDSS variability before randomization may limit treatment discovery in primary progressive MS

Background:

Baseline Expanded Disability Status Scale (EDSS) is usually based on a single measurement. Here we evaluated whether using a baseline EDSS derived from two pre-treatment measurements improves the detection of progression events and the ability to demonstrate a therapeutic effect in delaying MS disability progression.

Methods:

Real data from OLYMPUS, a phase II/III randomized, placebo-controlled trial of rituximab in patients with primary progressive multiple sclerosis (PPMS), as well as simulated data were analyzed. Several definitions of baseline EDSS were used to capture sustained disability progression (SDP) events. Variations in the EDSS were estimated by linear mixed-effect models.

Results:

Selecting the higher of two baseline EDSS scores lowered the number of SDP events in both treatment groups, so decreasing sensitivity, and reduced the number of false SDP events, so increasing specificity. Conversely, selecting the lower of two baseline scores increased sensitivity but decreased specificity. Increased power (~7% based on the simulation study) was observed when the average of screening and Week 0 EDSS scores was used for baseline.

Conclusion:

Baseline EDSS derived from two pre-treatment EDSS measurements may enhance the ability of detecting a therapeutic effect in slowing disability progression in PPMS. This strategy could be implemented in future clinical trials of patients with MS.

Motor fatigue measurement by distance-induced slow down of walking speed in multiple sclerosis

Background and rationale

Motor fatigue and ambulation impairment are prominent clinical features of people with multiple sclerosis (pMS). We hypothesized that a multimodal and comparative assessment of walking speed on short and long distance would allow a better delineation and quantification of gait fatigability in pMS. Our objectives were to compare 4 walking paradigms: the timed 25-foot walk (T25FW), a corrected version of the T25FW with dynamic start (T25FW⁺), the timed 100-meter walk (T100MW) and the timed 500-meter walk (T500MW).

Methods

Thirty controls and 81 pMS performed the 4 walking tests in a single study visit.

Results

The 4 walking tests were performed with a slower WS in pMS compared to controls even in subgroups with minimal disability. The finishing speed of the last 100-meter of the T500MW was the slowest measurable WS whereas the T25FW⁺ provided the fastest measurable WS. The ratio between such slowest and fastest WS (Deceleration Index, DI) was significantly lower only in pMS with EDSS 4.0–6.0, a pyramidal or cerebellar functional system score reaching 3 or a maximum reported walking distance ≤4000 m.

Conclusion

The motor fatigue which triggers gait deceleration over a sustained effort in pMS can be measured by the WS ratio between performances on a very short distance and the finishing pace on a longer more demanding task. The absolute walking speed is abnormal early in MS whatever the distance of effort when patients are unaware of ambulation impairment. In contrast, the DI-measured ambulation fatigability appears to take place later in the disease course.

Minimally important clinical difference of the Timed 25-Foot Walk Test: results from a randomized controlled trial in patients with multiple sclerosis

BACKGROUND

Limited data define what constitutes a clinically significant change on the Timed 25-Foot Walk (T25FW) in multiple sclerosis (MS); however, most studies suggest a value of ≥20%. Analyses were undertaken to estimate the minimally important clinical difference (MICD) in walking speed as measured by the T25FW in patients with MS.

METHODS

Data from MS-F203, a randomized trial of dalfampridine extended release tablets, 10 mg twice daily (prolonged-release/sustained-release fampridine outside the US) in patients with MS, were used to calculate the MICD, as an absolute and percentage value, for the T25FW test. Both anchor- (using the Clinician Global Impression [CGI]) and distribution-based (2.77 × standard error of measurement or 0.50 standard deviation units) approaches were used. Using the anchor-based estimations, the proportion of patients in the dalfampridine and placebo groups achieving at least a MICD in MS-F203 was determined.

RESULTS

A correlation between change in T25FW speed during and CGI at the end of double-blind period was found (Spearman r = -0.39, p < 0.0001). Irrespective of treatment group, participants categorized 'minimally improved' by the CGI had a mean improvement in T25FW speed of 0.36 feet/second or a 17.2% relative change from an average baseline walking speed of 2.1 feet/second (effect size = 0.49); values representing MICDs. MICD estimates of 0.35 and 0.37 feet/second were generated using distribution-based approaches. In MS-F203, a greater proportion of patients receiving dalfampridine achieved ≥0.36 feet/second (12/72 vs. 78/224, p = 0.007) and a 17.2% (11/72 vs. 87/224, p = 0.0005) improvement in T25FW speed compared to placebo.

LIMITATIONS

MICD estimates from this analysis may not apply to patients with different disease characteristics from MS-F203. A different anchor may result in a different MICD estimation.

CONCLUSION

Our MICD estimate for an improvement in T25FW is close to previous estimates of 20% change. Dalfampridine may improve walking speed in a considerable proportion of patients by a clinically relevant amount.

Effect of time of day on walking capacity and self-reported fatigue in persons with multiple sclerosis: a multi-center trial

BACKGROUND

Many persons with multiple sclerosis (PwMS) report increased fatigue in the afternoon and evening compared with the morning. It is commonly accepted that physical capacity also decreases as time of day progresses, potentially influencing the outcomes of testing.

OBJECTIVE

The objective of this article was to determine whether self-reported fatigue level and walking capacity are influenced by time of day in PwMS.

METHODS

A total of 102 PwMS from 8 centers in 5 countries, with a diverse level of ambulatory dysfunction (Expanded Disability Status Scale [EDSS] <6.5), participated. Patients performed walking capacity tests and reported fatigue level at three different time points (morning, noon, afternoon) during 1 day. Walking capacity was measured with the 6-Minute Walk Test (6MWT) and the 10-m walk test performed at usual and fastest speed. Self-reported fatigue was measured by the Rochester Fatigue Diary (RFD). Subgroups with mild (EDSS 1.5-4.0, n = 53) and moderate (EDSS 4.5-6.5, n = 49) ambulatory dysfunction were formed, as changes during the day were hypothesized to depend on disability status.

RESULTS

Subgroups had different degree of ambulatory dysfunction (p < 0.001) but reported similar fatigue levels. Although RFD scores were affected by time of day with significant differences between morning and noon/afternoon (p < 0.0001), no changes in walking capacity were found in any subgroup. Additional analyses on subgroups distinguished by diurnal change in self-reported fatigue failed to reveal analogous changes in walking capacity.

CONCLUSIONS

Testing of walking capacity is unaffected by time of day, despite changes in subjective fatigue.

Association between walking speed and age in healthy, free-living individuals using mobile accelerometry--a cross-sectional study

CONTEXT

Walking speed is a fundamental parameter of human motion and is increasingly considered as an important indicator of individuals' health status.

OBJECTIVE

To evaluate the relationship of gait parameters, and demographic and physical characteristics in healthy men and women.

DESIGN, SETTING, AND PARTICIPANTS

Recruitment of a subsample (n = 358) of male and female blood donors taking part in the Cambridge CardioResource study. Collection of demographic data, measurement of physical characteristics (height, weight and blood pressure) and assessment of 7-day, free-living activity parameters using accelerometry and a novel algorithm to measure walking speed. Participants were a median (interquartile range[IQR]) age of 49 (16) years; 45% women; and had a median (IQR) BMI of 26 (5.4).

MAIN OUTCOME MEASURE

Walking speed.

RESULTS

In this study, the hypothesis that walking speed declines with age was generated using an initial 'open' dataset. This was subsequently validated in a separate 'closed' dataset that showed a decrease of walking speed of -0.0037 m/s per year. This is equivalent to a difference of 1.2 minutes, when walking a distance of 1 km aged 20 compared to 60 years. Associations between walking speed and other participant characteristics (i.e. gender, BMI and blood pressure) were non-significant. BMI was negatively correlated with the number of walking and running steps and longest non-stop distance.

CONCLUSION

This is the first study using accelerometry which shows an association between walking speed and age in free-living, healthy individuals. Absolute values of gait speed are comparable to published normal ranges in clinical settings. This study highlights the potential use of mobile accelerometry to assess gait parameters which may be indicative of future health outcomes in healthy individuals.

Development and validation of a new method to measure walking speed in free-living environments using the actibelt® platform

Walking speed is a fundamental indicator for human well-being. In a clinical setting, walking speed is typically measured by means of walking tests using different protocols. However, walking speed obtained in this way is unlikely to be representative of the conditions in a free-living environment. Recently, mobile accelerometry has opened up the possibility to extract walking speed from long-time observations in free-living individuals, but the validity of these measurements needs to be determined. In this investigation, we have developed algorithms for walking speed prediction based on 3D accelerometry data (actibelt®) and created a framework using a standardized data set with gold standard annotations to facilitate the validation and comparison of these algorithms. For this purpose 17 healthy subjects operated a newly developed mobile gold standard while walking/running on an indoor track. Subsequently, the validity of 12 candidate algorithms for walking speed prediction ranging from well-known simple approaches like combining step length with frequency to more sophisticated algorithms such as linear and non-linear models was assessed using statistical measures. As a result, a novel algorithm employing support vector regression was found to perform best with a concordance correlation coefficient of 0.93 (95%CI 0.92–0.94) and a coverage probability CP1 of 0.46 (95%CI 0.12–0.70) for a deviation of 0.1 m/s (CP2 0.78, CP3 0.94) when compared to the mobile gold standard while walking indoors. A smaller outdoor experiment confirmed those results with even better coverage probability. We conclude that walking speed thus obtained has the potential to help establish walking speed in free-living environments as a patient-oriented outcome measure.

Treatment of walking impairment in multiple sclerosis with dalfampridine

Potassium channel blockade has long been considered a potential therapeutic strategy for treatment of multiple sclerosis (MS) based on the pathophysiology of demyelinated axons. Dalfampridine, which is also known as fampridine or 4-aminopyridine (4-AP), is the potassium channel blocker that has been studied most extensively in MS and other demyelinating neurologic disorders. An extended-release formulation of dalfampridine was recently approved by the US Food and Drug Administration to improve walking in patients with MS. In randomized, double-blind, placebo-controlled trials, with dalfampridine extended release tablets 10 mg taken twice daily, about 12 h apart, walking speed was improved in approximately one-third of treated patients; in these patients, average walking speed on therapy was about 25% above baseline. This improvement was clinically meaningful as assessed by concurrent measurement of patient-reported severity of walking-related disability. Dalfampridine extended release tablets were generally well tolerated, with a range of adverse effects that appear to be related to increases in central nervous system excitation. There is a dose-dependent increase in the occurrence of seizures at doses higher than the recommended 10 mg twice daily.

Dalfampridine: a brief review of its mechanism of action and efficacy as a treatment to improve walking in patients with multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) can cause progressive walking impairment that contributes to disability, loss of independence, and reduced quality of life. Dalfampridine (4-aminopyridine), a voltage-dependent potassium channel blocker, has been shown to improve walking in patients with MS, as demonstrated by an increase in walking speed.

OBJECTIVE

To summarize knowledge about the mechanism of action of dalfampridine in the context of clinical evidence of walking improvement in MS patients.

METHODS

Although this was not a systematic review, which is the primary limitation of this study, searches of PubMed were performed using relevant search terms to identify studies that examined the mechanism of action related to MS and its effects in patients with MS in clinical trials.

RESULTS

Voltage-gated potassium channels represent a family of related proteins that span cell membranes, open and close in response to changes in the transmembrane potential, and help regulate ionic potassium currents. Action potential conduction deficits in demyelinated axons result in part from the exposure after demyelination of the paranodal and internodal potassium channels that are distributed in the axonal membrane. This exposure leads to abnormal currents across the axonal membrane that can slow action potential conduction, result in conduction failure, or affect the axon's capacity for repetitive discharge. While dalfampridine is a broad-spectrum blocker of voltage-dependent potassium channels at millimolar concentrations, studies have shown improvement in action potential conduction in demyelinated axons at concentrations as low as 1 μM, and therapeutic plasma concentrations (associated with improved walking) are in the range of 0.25 µM. However, no specific potassium channel subtype has yet been characterized with significant sensitivity to dalfampridine in this range, and the effects of the drug at this low concentration appear to be quite selective. Improved conduction translates into clinical benefit as measured by objectively and subjectively assessed walking relative to placebo. Such improvements were observed in approximately one third of patients treated with an extended-release formulation of dalfampridine in clinical trials. These patients who responded to dalfampridine had an average increase in walking speed of approximately 25%, and greater improvements than nonresponders on a self-reported subjective measure of walking.

CONCLUSIONS

The extended-release formulation of dalfampridine has been shown in clinical trials to improve walking speed in approximately one third of MS patients with ambulatory impairment. The putative mechanism of action of dalfampridine is restoration of action potential conduction via blockade of an as yet uncharacterized subset of potassium channels in demyelinated axons.

Community walking can be assessed using a 10-metre timed walk test

Background: A decline in mobility is a common feature of multiple sclerosis (MS). Community walking scales are used to categorize patients in their ability to move independently. The first purpose of this study was to determine which specific gait speed corresponded with the categories of the Modified Functional Walking Categories (MFWC). The second purpose was to determine the Minimally Important Change (MIC) in absolute gait speed using the MFWC and Expanded Disability Status Scale (EDSS) as external criteria.

Method: MS patients were measured six times in 6 years. Gait velocity was measured with the 10-metre timed walk test (10-m TWT), the severity of MS was determined with the EDSS, and community walking was assessed with the MFWC. For each category of the MFWC, Receiver Operating Characteristic (ROC) curves were used to find the best possible cut-off point on the 10-m TWT. The MIC in absolute gait speed was determined using a change of one category on the MFWC or one point on the EDSS.

Results: A strong relationship was found between gait speed and the MFWC; all areas under the ROC curves (AUCs) were between 0.74 and 0.86. The MIC in absolute gait speed could not be determined, because the AUCs were below the threshold of 0.70 and changes in gait speed were small.

Conclusions: Gait speed is related to community walking, but an MIC in absolute gait speed could not be determined using a minimally important change on the MFWC or the EDSS as external criteria.

Evaluating walking in patients with multiple sclerosis: which assessment tools are useful in clinical practice?

Walking limitations are among the most visible manifestations of multiple sclerosis (MS). Regular walking assessments should be a component of patient management and require instruments that are appropriate from the clinician's and the patient's perspectives. This article reviews frequently used instruments to assess walking in patients with MS, with emphasis on their validity, reliability, and practicality in the clinical setting. Relevant articles were identified based on PubMed searches using the following terms: "multiple sclerosis AND (walking OR gait OR mobility OR physical activity) AND (disability evaluation)"; references of relevant articles were also searched. Although many clinician- and patient-driven instruments are available, not all have been validated in MS, and some are not sensitive enough to detect small but clinically important changes. Choosing among these depends on what needs to be measured, psychometric properties, the clinical relevance of results, and practicality with respect to space, time, and patient burden. Of the instruments available, the clinician-observed Timed 25-Foot Walk and patient self-report 12-Item Multiple Sclerosis Walking Scale have properties that make them suitable for routine evaluation of walking performance. The Dynamic Gait Index and the Timed Up and Go test involve other aspects of mobility, including balance. Tests of endurance, such as the 2- or 6-Minute Walk, may provide information on motor fatigue not captured by other tests. Quantitative measurement of gait kinetics and kinematics, and recordings of mobility in the patient's environment via accelerometry or Global Positioning System odometry, are currently not routinely used in the clinical setting.

Validation of the "Six Step Spot Test" for gait among patients with multiple sclerosis in Brazil

The clinical manifestations of multiple sclerosis (MS) are variable among patients, and the course of disease is not linear. Different symptoms are presented, with gradual accumulation of disability. These variations are difficult to quantify in clinical practice, and several studies have attempted to create instruments capable of measuring these disabilities. The Six Step Spot Test (SSST) was developed for quantitative evaluation of the lower limbs (LL) over time. Performance in this test reflects the complexity of sensory-motor function, including LL strength, spasticity, coordination and balance, going beyond vision and cognition. The aim of the present study was to validate the SSST in a population of MS patients in Brazil. This prospective study included 75 patients with MS, with EDSS 0 to 6.5 in the study group. Ninety-one healthy subjects were randomly selected for the control group. The results showed that the groups were similar, and that the SSST is a reliable and reproducible test. According to the statistical analysis on the data in this study, the SSST is a valid, reliable and reproducible tool for use in the Brazilian MS patient population.