Accelerometry as a measure of walking behavior in multiple sclerosis

The relationship between sleep quality and gait in people with multiple sclerosis: A pilot study

Background

Gait deficits are common among people with multiple sclerosis (PwMS). Therefore, investigating factors that may influence walking in PwMS is important. Previous studies in older adults and other neurological populations demonstrated the relationship between sleep quality and gait performance. Despite the fact that the prevalence of poor sleep quality is very high among PwMS, little is known about the effect of sleep quality on gait among PwMS.

Objective

This study aimed to explore the relationship between sleep quality and gait performance in PwMS.

Methods

Forty-one PwMS participated in the study between February 2019 and December 2019. Participants were asked to walk at a self-selected speed over 10 m with an inertial measurement unit (IMU) attached over the back. Walking speed, step length (left and right), and step time were calculated. Sleep was estimated objectively using a wrist-worn triaxle-accelerometer; the derived parameters were sleep efficiency (SE) and the number of awakening after sleep onset (NASO).

Results

SE significantly correlated with step length (p = 0 . 02 ). Furthermore, the NASO significantly correlated with gait speed (p = 0 . 03 ), and step-time (p = 0 . 02 ). These correlations remained significant even after adjusting for age and disease duration.

Conclusion

We observed that when corrected for disease duration and age there were relationships between NASO and SE to gait parameters; these observations warrant further investigations.

Translation and validation of the multiple sclerosis walking scale 12 for the German population - the MSWS-12/D

BACKGROUND

Gait impairment is a relevant problem in persons with multiple sclerosis (pwMS). The Multiple Sclerosis Walking Scale 12 (MSWS-12) is a valid Patient Reported Outcome Measure (PROM) to evaluate walking ability in pwMS. The aim of this study was to provide a linguistically valid translation of MSWS-12 into German language (MSWS-12/D) and to evaluate its psychometric properties.

METHODS

The MSWS-12 was translated in a process modified from guidelines for the cross-cultural adaption of PROMs, and a pre-test was applied in a small sample of 20 pwMS to evaluate comprehensibility and acceptance. Psychometric properties (floor and ceiling effects, internal consistency, construct validity) were then assessed in 124 pwMS seen at academic MS centers. Construct validity was evaluated against Expanded Disability Status Scale (EDSS) and maximum gait speed in the Timed 25-Foot Walk (T25FW).

RESULTS

Although the sample covered a wide spectrum of symptom severity, the majority had rather low levels of disability (EDSS median 2.0) and 6.5% scored EDSS of 0. In this sample, MSWS-12/D showed floor effects (36% with score 0) and for internal consistency, a Cronbach's alpha of 0.98 was calculated. MSWS-12/D score showed a relevant correlation to EDSS (ρ = 0.73) and T25FW speed (r=-0.72).

CONCLUSION

We provide MSWS-12/D as a linguistically valid German version of MSWS-12. Psychometric properties (acceptance, floor and ceiling effects, internal consistency and construct validity) in pwMS were similar to those described for the original version. This indicates that MSWS-12/D can be applied as equivalent to the original version in German speaking pwMS. Results support the relevance of PROMs to capture patient perception of walking ability in addition to performance-based assessments such as maximum walking speed or maximum walking distance.

Wearable Sensor Technologies to Assess Motor Functions in People With Multiple Sclerosis: Systematic Scoping Review and Perspective

BACKGROUND

Wearable sensor technologies have the potential to improve monitoring in people with multiple sclerosis (MS) and inform timely disease management decisions. Evidence of the utility of wearable sensor technologies in people with MS is accumulating but is generally limited to specific subgroups of patients, clinical or laboratory settings, and functional domains.

OBJECTIVE

This review aims to provide a comprehensive overview of all studies that have used wearable sensors to assess, monitor, and quantify motor function in people with MS during daily activities or in a controlled laboratory setting and to shed light on the technological advances over the past decades.

METHODS

We systematically reviewed studies on wearable sensors to assess the motor performance of people with MS. We scanned PubMed, Scopus, Embase, and Web of Science databases until December 31, 2022, considering search terms "multiple sclerosis" and those associated with wearable technologies and included all studies assessing motor functions. The types of results from relevant studies were systematically mapped into 9 predefined categories (association with clinical scores or other measures; test-retest reliability; group differences, 3 types; responsiveness to change or intervention; and acceptability to study participants), and the reporting quality was determined through 9 questions. We followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) reporting guidelines.

RESULTS

Of the 1251 identified publications, 308 were included: 176 (57.1%) in a real-world context, 107 (34.7%) in a laboratory context, and 25 (8.1%) in a mixed context. Most publications studied physical activity (196/308, 63.6%), followed by gait (81/308, 26.3%), dexterity or tremor (38/308, 12.3%), and balance (34/308, 11%). In the laboratory setting, outcome measures included (in addition to clinical severity scores) 2- and 6-minute walking tests, timed 25-foot walking test, timed up and go, stair climbing, balance tests, and finger-to-nose test, among others. The most popular anatomical landmarks for wearable placement were the waist, wrist, and lower back. Triaxial accelerometers were most commonly used (229/308, 74.4%). A surge in the number of sensors embedded in smartphones and smartwatches has been observed. Overall, the reporting quality was good.

CONCLUSIONS

Continuous monitoring with wearable sensors could optimize the management of people with MS, but some hurdles still exist to full clinical adoption of digital monitoring. Despite a possible publication bias and vast heterogeneity in the outcomes reported, our review provides an overview of the current literature on wearable sensor technologies used for people with MS and highlights shortcomings, such as the lack of harmonization, transparency in reporting methods and results, and limited data availability for the research community. These limitations need to be addressed for the growing implementation of wearable sensor technologies in clinical routine and clinical trials, which is of utmost importance for further progress in clinical research and daily management of people with MS.

TRIAL REGISTRATION

PROSPERO CRD42021243249; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=243249.

A Systematic Review of the Validity and Reliability of the Patient-Determined Disease Steps Scale

BACKGROUND

The Patient-Determined Disease Steps (PDDS) scale is a patient-reported measure of disability used by at least 3 North American multiple sclerosis (MS) registries. We conducted a systematic review of the psychometric properties of the PDDS scale as part of a harmonization effort related to disability measures used in MS registries.

METHODS

We searched the EMBASE, Ovid Medline, Scopus, Cochrane Database of Systematic Reviews, CENTRAL, CINAHL Plus, and ClinicalTrials.gov databases from database inception through July 28, 2020. Two reviewers independently screened abstracts and full-text reports for study inclusion and data extraction and assessed study quality and risk of bias. We included studies that assessed the validity or reliability of the PDDS scale. We conducted a meta-analysis to quantitatively summarize the findings.

RESULTS

From the 2476 abstracts screened, 234 articles underwent full-text review, of which 5 met the inclusion criteria. These studies assessed criterion validity, construct validity, and test-retest reliability. In all studies, criterion validity was assessed by correlating the PDDS scale score with the Expanded Disability Status Scale score (pooled r = 0.73; 95% CI, 0.66-0.79). Test-retest reliability was high (pooled intraclass correlation coefficient = 0.96; 95% CI, 0.92-0.99).

CONCLUSIONS

In this systematic review, the PDDS scale demonstrated criterion and construct validity for assessing disability in individuals with MS who have mild to moderate disabilities. This review also supports the test-retest reliability of the PDDS scale, although further studies with larger samples are needed.

Accelerometer measured physical activity and sedentary time in individuals with multiple sclerosis versus age matched controls: A systematic review and meta-analysis

BACKGROUND

People with Multiple Sclerosis (PwMS) find it more difficult to engage in physical activity (PA) than healthy controls. Accelerometers can be used to measure sedentary time and free-living physical activity, understanding the differences between PwMS and controls can help inform changes such as interventions to promote a more active lifestyle. This in turn will help prevent secondary conditions and reduce symptom progression.

OBJECTIVE

To conduct a systematic review and meta-analysis on accelerometer measured sedentary behavior and physical activity between PwMS and healthy controls.

METHODS

A systematic search of five databases (PubMed, Web of Science, Ovid, Science Direct and CINAHIL) from inception until 22nd November 2019. Inclusion criteria was (1) included a group of participants with a definite diagnosis of multiple sclerosis of any type; (2) have 3 or more days of PA monitoring using accelerometers during free living conditions; (3) include age matched healthy controls; (4) assess adults over the age of 18; (5) reported data had to have been reported in a manner suitable for quantitative pooling including: percent of time spent sedentary, minutes per day of sedentary, light, moderate, vigorous activity (moderate and vigorous totaled together), steps per day or counts per day.

RESULTS

Initial search produced 9021 papers, after applying inclusion criteria 21 eligible papers were included in the study. One paper was a longitudinal study from which only baseline data was included. One paper was a reliability and validity study, with data for PwMS versus controls in the validity section. All other papers are cross sectional, with one being a pilot study and another a random control study. One paper used two devices in unison, only one set of data is included in the statistics. Outcome data was available for 1098 participants, 579 PwMS and 519 healthy controls. Significant differences were seen in all categories tested: (1) sedentary time (min/day), standard mean difference -0.286, P = 0.044, n = 4 studies; (2) relative sedentary time (%/day), standard mean difference -0.646, P = 0.000, n = 5 studies; (3) LPA (min/day), standard mean difference 0.337, P = 0.039, n = 5 studies; (4) relative LPA (%/day), standard mean difference 0.211, P = 0.152, n = studies; (5) MVPA (min/day), standard mean difference 0.801, P = 0.000, n = 8 studies; (6) relative MVPA (%/day), mean difference 0.914, P = 0.000, n = 5 studies; (7) step count, standard mean difference 0.894, P = 0.000, n = 8 studies; (8) activity count, standard mean difference 0.693, P = 0.000, n = 13 studies.

CONCLUSION

PwMS are more sedentary and engage in less LPA, MVPA, steps per day and accelerometer counts per day than healthy controls when measured using accelerometers during free-living conditions.

Objective and subjective measures of daily physical activity in persons with Multiple Sclerosis beginning a rehabilitation regime: A cross-sectional study

INTRODUCTION

Fatigue, and balance and gait disorders can impact on physical activity (PA) levels in persons with Multiple Sclerosis (pwMS). To date, several studies have examined PA in pwMS during daily life, but little is known about PA levels in pwMS during a rehabilitation period. The present study investigated PA levels (daily steps, light physical activity (LPA), and moderate-vigorous physical activity (MVPA)) in inpatient and outpatients with MS during their rehabilitation period and described the relationship between objectively measured PA and levels of disability, quality of life, fatigue, and self-efficacy.

METHODS

In this exploratory cross-sectional study, we examined 40 pwMS during their inpatient or outpatient rehabilitation regime. Participants included in the study (N = 34) wore a Fitbit Versa tracker for one week recording daily steps, minutes of LPA, and minutes of MVPA (primary outcomes). They underwent a clinical assessment of physical activity levels (Godin Leisure-Time Exercise Questionnaire(GLTEQ)), fatigue (Fatigue Severity Scale(FSS)), walking ability (10 Meter Walk Test(10MWT), 2-Min Walk Test(2MWT), 12-item Multiple Sclerosis Walking scale(MSWS-12)), quality of life (12-Item Short Form Survey (SF-12)), and self-efficacy (Self-Efficacy in Multiple Sclerosis scale (SEMS)) (secondary outcomes). Multiple linear regressions (MLR) models were used to test whether the demographic difference between the two groups influenced the estimation of objective variables measured by Fitbit. Finally, correlations between objectively measured physical activity and subjective clinical scales were estimated with Spearman correlations.

RESULTS

Our sample consisted of 21 females and 13 males with a mean (interquartile range) age of 52 (20) years and an Expanded Disability Status scale(EDSS) score of 6.0 (1.50) points; baseline characteristics of inpatients (N = 18) and outpatients (N = 16) differed statistically only in EDSS levels (p-value = 0.008) and use of assistive devices (p=0.007). The whole sample performed (mean±standard deviation) 3969±2190 steps per day, with no significant difference between inpatients (3318±1515) and outpatients (4660±2606). No statistical difference was found between the groups in LPA (p-value=0.064). A significant difference in MVPA (p-value < 0.001) was found between inpatients and outpatients, 1.52±3.98 and 14.69±11.56 min per day, respectively. Significant correlations were found between FSS and MVPA both in the whole sample (r(32)= -0.62, p < 0.001) and in the outpatients group (r(14) = -0.66, p = 0.005), and between 10MWT and daily steps (whole sample:(r(32) = 0.48, p = 0.005), outpatients:(r(14)= -0.51, p = 0.05)).

CONCLUSIONS

PwMS in our study overall engaged in reduced and less intense levels of daily PA with respect to the guidelines with inpatients performing almost no vigorous activities. Considering the importance of PA in improving physical and mental well-being, clinicians and researchers should develope strategies to increase daily PA of PwMS during their rehabilitation programs and daily life.

Gait Variability to Phenotype Common Orthopedic Gait Impairments Using Wearable Sensors

Mobility impairments are a common symptom of age-related degenerative diseases. Gait features can discriminate those with mobility disorders from healthy individuals, yet phenotyping specific pathologies remains challenging. This study aims to identify if gait parameters derived from two foot-mounted inertial measurement units (IMU) during the 6 min walk test (6MWT) can phenotype mobility impairment from different pathologies (Lumbar spinal stenosis (LSS)-neurogenic diseases, and knee osteoarthritis (KOA)-structural joint disease). Bilateral foot-mounted IMU data during the 6MWT were collected from patients with LSS and KOA and matched healthy controls (N = 30, 10 for each group). Eleven gait parameters representing four domains (pace, rhythm, asymmetry, variability) were derived for each minute of the 6MWT. In the entire 6MWT, gait parameters in all four domains distinguished between controls and both disease groups; however, the disease groups demonstrated no statistical differences, with a trend toward higher stride length variability in the LSS group (p = 0.057). Additional minute-by-minute comparisons identified stride length variability as a statistically significant marker between disease groups during the middle portion of 6WMT (3rd min: p ≤ 0.05; 4th min: p = 0.06). These findings demonstrate that gait variability measures are a potential biomarker to phenotype mobility impairment from different pathologies. Increased gait variability indicates loss of gait rhythmicity, a common feature in neurologic impairment of locomotor control, thus reflecting the underlying mechanism for the gait impairment in LSS. Findings from this work also identify the middle portion of the 6MWT as a potential window to detect subtle gait differences between individuals with different origins of gait impairment.

Methodological heterogeneity biases physical activity metrics derived from the Actigraph GT3X in multiple sclerosis: A rapid review and comparative study

BACKGROUND

Physical activity (PA) is reduced in persons with multiple sclerosis (MS), though it is known to aid in symptom and fatigue management. Methods for measuring PA are diverse and the impact of this heterogeneity on study outcomes is unclear. We aimed to clarify this impact by comparing common methods for deriving PA metrics in MS populations.

METHODS

First, a rapid review of existing literature identified methods for calculating PA in studies which used the Actigraph GT3X in populations with MS. We then compared methods in a prospective study on 42 persons with MS [EDSS 4.5 (3.5-6)] during a voluntary course of inpatient neurorehabilitation. Mixed-effects linear regression identified methodological factors which influenced PA measurements. Non-parametric hypothesis tests, correlations, and agreement statistics assessed overall and pairwise differences between methods.

RESULTS

In the rapid review, searches identified 421 unique records. Sixty-nine records representing 51 eligible studies exhibited substantial heterogeneity in methodology and reporting practices. In a subsequent comparative study, multiple methods for deriving six PA metrics (step count, activity counts, total time in PA, sedentary time, time in light PA, time in moderate to vigorous PA), were identified and directly compared. All metrics were sensitive to methodological factors such as the selected preprocessing filter, data source (vertical vs. vector magnitude counts), and cutpoint. Additionally, sedentary time was sensitive to wear time definitions. Pairwise correlation and agreement between methods varied from weak (minimum correlation: 0.15, minimum agreement: 0.03) to perfect (maximum correlation: 1.00, maximum agreement: 1.00). Methodological factors biased both point estimates of PA and correlations between PA and clinical assessments.

CONCLUSIONS

Methodological heterogeneity of existing literature is high, and this heterogeneity may confound studies which use the Actigraph GT3X. Step counts were highly sensitive to the filter used to process raw accelerometer data. Sedentary time was particularly sensitive to methodology, and we recommend using total time in PA instead. Several, though not all, methods for deriving light PA and moderate to vigorous PA yielded nearly identical results. PA metrics based on vertical axis counts tended to outperform those based on vector magnitude counts. Additional research is needed to establish the relative validity of existing methods.

Muscle architecture and its relationship with lower extremity muscle strength in multiple sclerosis

This study was planned to determine the muscle architecture (pennation angle, muscle fiber length, and muscle thickness) and its relationship to lower extremity muscle strength in patients with Multiple Sclerosis (pwMS). The muscle architecture (pennation angle, muscle fiber length, and muscle thickness) and lower extremity muscle strength were assessed in 33 pwMS [13 Relapsing-Remitting MS (RRMS), 5 Primary Progressive MS (PPMS), 5 Secondary Progressive MS (SPMS), and 11 matched healthy controls (HC)]. Muscle architecture features were assessed with ultrasonography and muscle strength were assessed with a digital hand-held dynamometer. The rectus femoris muscle thickness and pennation angle, gastrocnemius muscle thickness, and the tibialis anterior pennation angle were significantly lower in pwMS compared to HC (p < 0.05). The strength of hip flexors, hip extensors, knee extensors, foot plantar, and foot dorsi flexors were lower in pwMS. In PPMS group, muscle strength of hip flexors was lower than RRMS and SPMS groups, and muscle strength of foot dorsi flexors was lower than RRMS (p < 0.05). In pwMS, positive correlations were found, between knee flexor strength and biceps femoris pennation angle. Also knee extensor strength and rectus femoris fiber length and muscle thickness were correlated positively (p < 0.05). According to our results the muscle architecture is affected in MS. The determination of architectural changes of lower extremity muscles may guide the arrangement of optimal strength exercises in functional rehabilitation programs.ClinicalTrials: NCT03766698.

The Relationship Between Walking Speed and the Energetic Cost of Walking in Persons With Multiple Sclerosis and Healthy Controls: A Systematic Review

BACKGROUND

Persons with multiple sclerosis (pwMS) experience walking impairments, characterized by decreased walking speeds. In healthy subjects, the self-selected walking speed is the energetically most optimal. In pwMS, the energetically most optimal walking speed remains underexposed. Therefore, this review aimed to determine the relationship between walking speed and energetic cost of walking (Cw) in pwMS, compared with healthy subjects, thereby assessing the walking speed with the lowest energetic cost. As it is unclear whether the Cw in pwMS differs between overground and treadmill walking, as reported in healthy subjects, a second review aim was to compare both conditions.

METHOD

PubMed and Web of Science were systematically searched. Studies assessing pwMS, reporting walking speed (converted to meters per second), and reporting oxygen consumption were included. Study quality was assessed with a modified National Heart, Lung and Blood Institute checklist. The relationship between Cw and walking speed was calculated with a second-order polynomial function and compared between groups and conditions.

RESULTS

Twenty-nine studies were included (n = 1535 pwMS) of which 8 included healthy subjects (n = 179 healthy subjects). PwMS showed a similar energetically most optimal walking speed of 1.44 m/s with a Cw of 0.16, compared with 0.14 mL O₂/kg/m in healthy subjects. The most optimal walking speed in treadmill was 1.48 m/s, compared with 1.28 m/s in overground walking with a similar Cw.

CONCLUSION

Overall, the Cw is elevated in pwMS but with a similar energetically most optimal walking speed, compared with healthy subjects. Treadmill walking showed a similar most optimal Cw but a higher speed, compared with overground walking.

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.

What gait features influence the amount and intensity of physical activity in people with multiple sclerosis?

Although the mutual relationship between ambulation and physical activity (PA) in people with multiple sclerosis (pwMS) has been described in several studies, there is still a lack of detailed information about the way in which specific aspects of the gait cycle are associated with amount and intensity of PA. This study aimed to verify the existence of possible relationships among PA parameters and the spatio-temporal parameters of gait when both are instrumentally assessed.Thirty-one pwMS (17F, 14 M, mean age 52.5, mean Expanded Disability Status Scale (EDSS) score 3.1) were requested to wear a tri-axial accelerometer 24 hours/day for 7 consecutive days and underwent an instrumental gait analysis, performed using an inertial sensor located on the low back, immediately before the PA assessment period. Main spatio-temporal parameters of gait (i.e., gait speed, stride length, cadence and duration of stance, swing, and double support phase) were extracted by processing trunk accelerations. PA was quantified using average number of daily steps and percentage of time spent at different PA intensity, the latter calculated using cut-point sets previously validated for MS. The existence of possible relationships between PA and gait parameters was assessed using Spearman rank correlation coefficient rho.Gait speed and stride length were the parameters with the highest number of significant correlations with PA features. In particular, they were found moderately to largely correlated with number of daily steps (rho 0.62, P< .001), percentage of sedentary activity (rho = -0.44, P < .001) and percentage of moderate-to-vigorous activity (rho = 0.48, P < .001). Small to moderate significant correlations were observed between PA intensity and duration of stance, swing and double support phases.The data obtained suggest that the most relevant determinants associated with higher and more intense levels of PA in free-living conditions are gait speed and stride length. The simultaneous quantitative assessment of gait parameters and PA levels might represent a useful support for physical therapists in tailoring optimized rehabilitative and training interventions.

Performance fatigability during gait in adults with Charcot-Marie-Tooth disease

BACKGROUND

Fatigue is common in people with Charcot-Marie-Tooth (pwCMT) disease. However, no studies have characterized performance fatigability during gait in this population. Characterizing performance fatigability during gait, and assessing its relation to life satisfaction could improve understanding and treatment of mobility challenges in pwCMT.

RESEARCH QUESTIONS

How do gait outcomes change with fatigue in pwCMT? Do these changes relate to life satisfaction?

METHODS

31 pwCMT completed a 6-minute, fast-as-possible walk while gait outcomes were captured via inertial sensors. Gait outcomes were separated into six sequential bins of equal size. The mean value, variability, and asymmetry (step time only) of outcomes were calculated for each bin. Perceived fatigue and general life satisfaction were assessed via questionnaire.

RESULTS

Of the five mean gait outcomes measured, four showed statistically significant changes over the 6-minute fast-as-possible walk: velocity (reduced; p = 0.008); cadence (reduced; p < 0.001), step time (increased; p < 0.001), and trunk ROM (increased; p = 0.032). Of the four variability and one asymmetry outcomes, only stride length variability changed during the walking task (p = 0.015), decreasing from bins 1-2, and remaining stable for bins 2-6. Changes in velocity, cadence, step time were related to general life satisfaction (0.038 < ps<0.04), but not perceived fatigue (ps>0.343).

SIGNIFICANCE

pwCMT exhibit statistically significant changes in mean gait outcomes, but not variability outcomes, across a 6-minute, fast-as-possible walking bout. Changes correlated to life satisfaction, suggesting performance fatigability during gait could be a target for rehabilitation for pwCMT. Perceived fatigue did not correlate to gait fatigue, underscoring the differentiation between perceived fatigue and performance fatigability.

Telehealth in Multiple Sclerosis Clinical Care and Research

Purpose of Review

The COVID-19 pandemic has provided us with a unique opportunity to experiment with telehealth and evaluate its benefits and limitations. This review discusses the impact of telehealth on multiple sclerosis (MS) care and research in adults and children.

Recent Findings

Telehealth visits for MS patients have been shown to reduce missed workdays and costs for patients. Brief telephone-based counseling may be associated with better adherence to disease-modifying therapy, although results of multiple home-based tele-rehabilitation for people with MS have been equivocal. Overall, patients and providers have reported high levels of satisfactions with telehealth. Several remote disability measures and numerous other technological tools have emerged for use in remote MS research and care. Major challenges of telehealth include limitations to performing a complete neurologic exam and disparities in access to telehealth amongst vulnerable populations with limited access to virtual platforms.

Summary

Following the rapid expansion of telehealth during the pandemic, it is highly likely that we will continue to embrace the benefits of this valuable tool. Future directions for improving telehealth should include more evidence-based research on the diagnostic accuracy in neuroimmunology and reducing disparities in the access to telehealth.

Anwendung von Wearables bei Multipler Sklerose

Wearables sind mit Sensoren ausgestattete Geräte oder Funktionskleidung, welche im Bereich der Multiplen Sklerose bis dato v. a. zur Messung von Bewegung in Form von Accelerometern in Verwendung sind. Im Gegensatz zu technisch aufwendigen Ganganalysesystemen und neurologischen Funktionstests können solche Wearables im Alltag einfach eingesetzt werden und bieten die Möglichkeit Ausmaß, Geschwindigkeit und Dauer von Bewegung auch über längere Zeiträume zu erfassen. Zusätzlich können auch spezifischere Parameter wie Schrittlänge, Bewegungsumfang einzelner Gelenke sowie physiologische und pathologische Bewegungsmuster dokumentiert werden. Die durch Accelerometer erhobenen Informationen korrelieren gut mit der körperlichen Aktivität im Alltag, kardiorespiratorischen Biomarkern der Bewegung, dem Ausmaß der Behinderung aber auch mit technisch aufwendigen Ganganalysen.

Insofern werden Wearables in Zukunft eine immer wichtigere Rolle spielen, wenn es darum geht, die Beweglichkeit als einen der wichtigsten Faktoren der Lebensqualität von Personen mit MS im Alltag reliabel und einfach zu messen.

Does gait bout definition influence the ability to discriminate gait quality between people with and without multiple sclerosis during daily life?

BACKGROUND

There is currently no consensus about standardized gait bout definitions when passively monitoring walking during normal daily life activities. It is also not known how different definitions of a gait bout in daily life monitoring affects the ability to distinguish pathological gait quality. Specifically, how many seconds of a pause with no walking indicates an end to one gait bout and the start of another bout? In this study, we investigated the effect of 3 gait bout definitions on the discriminative ability to distinguish quality of walking in people with multiple sclerosis (MS) from healthy control subjects (HC) during a week of daily living.

METHODS

15 subjects with MS and 16 HC wore instrumented socks on each foot and one Opal sensor over the lower lumbar area for a week of daily activities for at least 8 h/day. Three gait bout definitions were based on the length of the pause between the end of one gait bout and start of another bout (1.25 s, 2.50 s, and 5.0 s pause). Area under the curve (AUC) was used to compare gait quality measures in MS versus HC.

RESULTS

Total number of gait bouts over the week were statistically significantly different across bout definitions, as expected. However, AUCs of gait quality measures (such as gait speed, stride length, stride time) discriminating people with MS from HC were not different despite the 3 bout definitions.

SIGNIFICANCE

Quality of gait measures that discriminate MS from HC during daily life are not influenced by the length of a gait bout, despite large differences in quantity of gait across bout definitions. Thus, gait quality measures in people with MS versus controls can be compared across studies using different gait bout definitions with pause lengths ≤5 s.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

IMPACT

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

The Two-Minute Walk Test in Persons with Multiple Sclerosis: Correlations of Cadence with Free-Living Walking Do Not Support Ecological Validity

The two-minute walk test (2MWT) is a frequently used walking capacity test in persons with multiple sclerosis (pwMS). However, less is known about its relevance with regards to walking capacity during free-living walking performance. Therefore, the ecological validity of the 2MWT was tested by 1. computing free-living minutes with the same intensity (cadence) as during the 2MWT and 2. investigating the relationship between 2MWT cadence and minutes with the same cadence during free-living walking. 20 pwMS aged 44.2 ± 12.2 (Expanded Disability Status Scale (EDSS) score of 3.1 ± 1.4) performed a 2MWT and wore an accelerometer for seven days. The number of pwMS reaching 100%, 90%, 80% or 70% of 2MWT cadence for at least one minute a day and minutes/day with at least 100%, 90%, 80% and 70% of 2MWT cadence during free-living walking was calculated. Six participants reached 100% of the 2MWT cadence for at least one minute/day during free-living walking. A total of 80% 2MWT cadence was the first intensity category that was reached by all participants during free-living walking. No significant correlation was found between cadence in the 2MWT and minutes in which this cadence was reached during free-living walking. Ecological validity with regard to walking intensity could not be confirmed in our study sample.

Gait analysis in neurological populations: Progression in the use of wearables

Gait assessment is an essential tool for clinical applications not only to diagnose different neurological conditions but also to monitor disease progression as it contributes to the understanding of underlying deficits. There are established methods and models for data collection and interpretation of gait assessment within different pathologies. This narrative review aims to depict the evolution of gait assessment from observation and rating scales to wearable sensors and laboratory technologies and provide limitations and possible future directions in the field of gait assessment. In this context, we first present an extensive review of current clinical outcomes and gait models. Then, we demonstrate commercially available wearable technologies with their technical capabilities along with their use in gait assessment studies for various neurological conditions. In the next sections, a descriptive knowledge for existing inertial and EMG based algorithms and a sign based guide that shows the outcomes of previous neurological gait assessment studies are presented. Finally, we state a discussion for the use of wearables in gait assessment and speculate the possible research directions by revealing the limitations and knowledge gaps in the literature.

Device-Measured Physical Activity and Cognitive Processing Speed Impairment in a Large Sample of Persons with Multiple Sclerosis

OBJECTIVE

There is accumulating evidence regarding the beneficial effects of physical activity (PA) on cognitive processing speed in persons with multiple sclerosis (MS). However, one overarching limitation of this research is that researchers have not recruited samples who have the actual problem of being studied (i.e., cognitive processing speed impairment). This study examined associations between device-measured PA and cognitive processing speed in a large sample of persons with MS overall and between those with and without cognitive processing speed impairment.

METHOD

Three hundred eighty-five persons with MS underwent the oral Symbol Digit Modalities Test (SDMT) and wore an accelerometer for 7 days for PA measurement. We divided the overall sample into subsamples with (n = 140) and without (n = 245) cognitive processing speed impairment based on age, sex, and education-adjusted SDMT Z-scores.

RESULTS

After controlling for age and disability status, higher levels of device-measured PA were significantly associated with faster cognitive processing speed overall, and the association was significantly stronger among persons with MS who presented with cognitive processing speed impairment.

CONCLUSIONS

This examination provides initial cross-sectional support for informing the development of PA interventions as a possible approach for managing MS-related cognitive processing speed impairment. This highlights the importance of developing purposefully designed trials involving PA interventions for targeting cognitive processing speed as a primary end point among persons with MS with impaired cognitive processing speed.

Clinically Assessed Walking Capacity Versus Real-World Walking Performance in People with Multiple Sclerosis

Background

Ecological validity is an important psychometric property when assessing function. How a person with multiple sclerosis (MS) performs in clinical settings and in natural environments can be quite different. Walking is the most frequently assessed and recommended way to maintain health in a progressive disease such as MS. The objective was to estimate the extent to which clinical tests of walking capacity differ from real-world walking performance in people with MS.

Methods

Ninety-eight women and 27 men with MS were assessed using the 6-Minute Walk Test (6MWT) and wore an accelerometer for 7 consecutive days. Mean number of steps, mean number of steps at a brisk cadence or faster, and cumulative time per week spent walking at a brisk cadence or faster were regressed on 6MWT categories using quantile (median) regression. Contiguous steps were grouped into bouts of less than 5 minutes and 5 minutes or longer, and number of bouts 5 minutes or longer was regressed on 6MWT categories using a zero-inflated Poisson model.

Results

A total of 869 patient-days of accelerometer data were available. Mean total number of steps per day was greater for people with higher walking capacity (6MWT distance, ≥600 m). However, this group spent a small proportion of time walking at higher cadence bands. Compared with people with 6MWT distance of at least 600 m, people walking less than 500 m had approximately half the rate of walking bouts of 5 minutes or longer. Positive mood and fewer exercise barriers predicted more walking bouts of at least 5 minutes.

Conclusions

Study participants with MS spent a small proportion of time walking at a health-promoting intensity.

Wearable sensors can reliably quantify gait alterations associated with disability in people with progressive multiple sclerosis in a clinical setting

Gait disability in people with progressive multiple sclerosis (MS) is difficult to quantify using existing clinical tools. This study aims to identify reliable and objective gait-based biomarkers to monitor progressive multiple sclerosis (MS) in clinical settings. During routine clinical visits, 57 people with secondary progressive MS and 24 healthy controls walked for 6 minutes wearing three inertial motion sensors. Fifteen gait measures were computed from the sensor data and tested for between-session reliability, for differences between controls and people with moderate and severe MS disability, and for correlation with Expanded Disability Status Scale (EDSS) scores. The majority of gait measures showed good to excellent between-session reliability when assessed in a subgroup of 23 healthy controls and 25 people with MS. These measures showed that people with MS walked with significantly longer step and stride durations, reduced step and stride regularity, and experienced difficulties in controlling and maintaining a stable walk when compared to controls. These abnormalities significantly increased in people with a higher level of disability and correlated with their EDSS scores. Reliable and objective gait-based biomarkers using wearable sensors have been identified. These biomarkers may allow clinicians to quantify clinically relevant alterations in gait in people with progressive MS within the context of regular clinical visits.

A wearable sensor identifies alterations in community ambulation in multiple sclerosis: contributors to real-world gait quality and physical activity

People with multiple sclerosis (pwMS) often suffer from gait impairments. These changes in gait have been well studied in laboratory and clinical settings. A thorough investigation of gait alterations during community ambulation and their contributing factors, however, is lacking. The aim of the present study was to evaluate community ambulation and physical activity in pwMS and healthy controls and to compare in-lab gait to community ambulation. To this end, 104 subjects were studied: 44 pwMS and 60 healthy controls (whose age was similar to the controls). The subjects wore a tri-axial, lower back accelerometer during usual-walking and dual-task walking in the lab and during community ambulation (1 week) to evaluate the amount, type, and quality of activity. The results showed that during community ambulation, pwMS took fewer steps and walked more slowly, with greater asymmetry, and larger stride-to-stride variability, compared to the healthy controls (p < 0.001). Gait speed during most of community ambulation was significantly lower than the in-lab usual-walking value and similar to the in-lab dual-tasking value. Significant group (pwMS /controls)-by-walking condition (in-lab/community ambulation) interactions were observed (e.g., gait speed). Greater disability was associated with fewer steps and reduced gait speed during community ambulation. In contrast, physical fatigue was correlated with sedentary activity, but was not related to any of the measures of community ambulation gait quality including gait speed. This disparity suggests that more than one mechanism contributes to community ambulation and physical activity in pwMS. Together, these findings demonstrate that during community ambulation, pwMS have marked gait alterations in multiple gait features, reminiscent of dual-task walking measured in the laboratory. Disease-related factors associated with these changes might be targets of rehabilitation.

The Coefficient of Variation of Step Time Can Overestimate Gait Abnormality: Test-Retest Reliability of Gait-Related Parameters Obtained with a Tri-Axial Accelerometer in Healthy Subjects

The aim of this study was to investigate whether variation in gait-related parameters among healthy participants could help detect gait abnormalities. In total, 36 participants (21 men, 15 women; mean age, 35.7 ± 9.9 years) performed a 10-m walk six times while wearing a tri-axial accelerometer fixed at the L3 level. A second walk was performed ≥1 month after the first (mean interval, 49.6 ± 7.6 days). From each 10-m data set, the following nine gait-related parameters were automatically calculated: assessment time, number of steps, stride time, cadence, ground force reaction, step time, coefficient of variation (CV) of step time, velocity, and step length. Six repeated measurement values were averaged for each gait parameter. In addition, for each gait parameter, the difference between the first and second assessments was statistically examined, and the intraclass correlation coefficient (ICC) was calculated with the level of significance set at p < 0.05. Only the CV of step time showed a significant difference between the first and second assessments (p = 0.0188). The CV of step time also showed the lowest ICC, at <0.50 (0.425), among all parameters. Test-retest results of gait assessment using a tri-axial accelerometer showed sufficient reproducibility in terms of the clinical evaluation of all parameters except the CV of step time.

Physical activity and peak oxygen consumption are associated with walking in multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system with a prevalence of nearly 1 million adults in the United States. MS results in declines in physical activity and peak oxygen consumption that might be independently associated with declines in walking performance. Therefore our purpose was to evaluate the association between physical activity and peak oxygen consumption with walking performance in individuals with MS.

METHODS

Fifty individuals with MS between the ages of 18-70 yrs. (Female: 38; 46  ±  12 yrs.; BMI: 28.5  ±  6.4; EDSS: 3.3 [IQR: 2.5-4]) performed a maximal incremental cycle test to assess peak oxygen consumption (VO_2peak), and wore an accelerometer for one week to measure moderate-to-vigorous physical activity (MVPA). Subjects further completed a timed 25-foot walk test (T25FW) and 6-minute walk (6MW) to measure walking performance.

RESULTS

MVPA and VO₂peak were correlated with 6MW and T25FW (p < 0.05). When combined in multivariate regression analyses, VO_2peak and MVPA were both significant contributors of T25FW speed and 6MW, but after controlling for sex and age, MVPA was the only significant contributor (β = 0.32 and β = 0.44, respectively).

CONCLUSION

Both higher MVPA and VO_2peak were associated with better walking performance and in a combined model physical activity, but not peak oxygen consumption, remained an independent contributor to walking performance in individuals with MS. These results suggest that improving MVPA is a potential target for interventions to improve walking performance in persons with MS.

Comfortable walking speed and energy cost of locomotion in patients with multiple sclerosis

Comfortable walking speed and energy cost of walking are physiological markers of metabolic activity during gait. People with multiple sclerosis are characterized by altered gait biomechanics and energetics, related to the degree of disability and spasticity, which lead to an increased energy cost of walking. Several studies concerning the energy cost of walking in multiple sclerosis have been published. Nevertheless, differences in protocols and characteristics of the sample have led to different outcomes. The aim of the present meta-analysis is to summarize results from studies with specific inclusion characteristics, and to present data about the comfortable walking speed and the energy cost of walking at that speed. Moreover, a detailed discussion of the potential mechanisms involved in the altered metabolic activity during exercise was included. A total of 19 studies were considered, 12 of which were also part of the quantitative analysis. Despite the strict selection process, high between-group heterogeneity was found for both outcomes. Nevertheless, the overall results suggest a pooled mean comfortable walking speed of 1.12 m/s (95% CI 1.05-1.18) and energy cost of 0.19 mLO₂/kg/m (95% CI 0.17-0.21). These findings support the results of previous studies suggesting that energy cost of walking may be increased by 2-3 times compared to healthy controls (HC), and encourage the use of this marker in association with other parameters of the disease.

Is a Wearable Sensor-Based Characterisation of Gait Robust Enough to Overcome Differences Between Measurement Protocols? A Multi-Centric Pragmatic Study in Patients with Multiple Sclerosis

Inertial measurement units (IMUs) allow accurate quantification of gait impairment of people with multiple sclerosis (pwMS). Nonetheless, it is not clear how IMU-based metrics might be influenced by pragmatic aspects associated with clinical translation of this approach, such as data collection settings and gait protocols. In this study, we hypothesised that these aspects do not significantly alter those characteristics of gait that are more related to quality and energetic efficiency and are quantifiable via acceleration related metrics, such as intensity, smoothness, stability, symmetry, and regularity. To test this hypothesis, we compared 33 IMU-based metrics extracted from data, retrospectively collected by two independent centres on two matched cohorts of pwMS. As a worst-case scenario, a walking test was performed in the two centres at a different speed along corridors of different lengths, using different IMU systems, which were also positioned differently. The results showed that the majority of the temporal metrics (9 out of 12) exhibited significant between-centre differences. Conversely, the between-centre differences in the gait quality metrics were small and comparable to those associated with a test-retest analysis under equivalent conditions. Therefore, the gait quality metrics are promising candidates for reliable multi-centric studies aiming at assessing rehabilitation interventions within a routine clinical context.

Quantifying neurologic disease using biosensor measurements in-clinic and in free-living settings in multiple sclerosis

Technological advances in passive digital phenotyping present the opportunity to quantify neurological diseases using new approaches that may complement clinical assessments. Here, we studied multiple sclerosis (MS) as a model neurological disease for investigating physiometric and environmental signals. The objective of this study was to assess the feasibility and correlation of wearable biosensors with traditional clinical measures of disability both in clinic and in free-living in MS patients. This is a single site observational cohort study conducted at an academic neurological center specializing in MS. A cohort of 25 MS patients with varying disability scores were recruited. Patients were monitored in clinic while wearing biosensors at nine body locations at three separate visits. Biosensor-derived features including aspects of gait (stance time, turn angle, mean turn velocity) and balance were collected, along with standardized disability scores assessed by a neurologist. Participants also wore up to three sensors on the wrist, ankle, and sternum for 8 weeks as they went about their daily lives. The primary outcomes were feasibility, adherence, as well as correlation of biosensor-derived metrics with traditional neurologist-assessed clinical measures of disability. We used machine-learning algorithms to extract multiple features of motion and dexterity and correlated these measures with more traditional measures of neurological disability, including the expanded disability status scale (EDSS) and the MS functional composite-4 (MSFC-4). In free-living, sleep measures were additionally collected. Twenty-three subjects completed the first two of three in-clinic study visits and the 8-week free-living biosensor period. Several biosensor-derived features significantly correlated with EDSS and MSFC-4 scores derived at visit two, including mobility stance time with MSFC-4 z-score (Spearman correlation −0.546; p = 0.0070), several aspects of turning including turn angle (0.437; p = 0.0372), and maximum angular velocity (0.653; p = 0.0007). Similar correlations were observed at subsequent clinic visits, and in the free-living setting. We also found other passively collected signals, including measures of sleep, that correlated with disease severity. These findings demonstrate the feasibility of applying passive biosensor measurement techniques to monitor disability in MS patients both in clinic and in the free-living setting.

Deterioration of specific aspects of gait during the instrumented 6-min walk test among people with multiple sclerosis

Prolonged walking is typically impaired among people with multiple sclerosis (pwMS), however, it is unclear what the contributing factors are or how to evaluate this deterioration. We aimed to determine which gait features become worse during sustained walking and to examine the clinical correlates of gait fatigability in pwMS. Fifty-eight pwMS performed the 6-min walk test while wearing body-fixed sensors. Multiple gait domains (e.g., pace, rhythm, variability, asymmetry and complexity) were compared across each minute of the test and between mild- and moderate-disability patient groups. Associations between the decline in gait performance (i.e., gait fatigability) and patient-reported gait disability, fatigue and falls were also determined. Cadence, stride time variability, stride regularity, step regularity and gait complexity significantly deteriorated during the test. In contrast, somewhat surprisingly, gait speed and swing time asymmetry did not change. As expected, subjects with moderate disability (n = 24) walked more poorly in most gait domains compared to the mild-disability group (n = 34). Interestingly, a group × fatigue interaction effect was observed for cadence and gait complexity; these measures decreased over time in the moderate-disability group, but not in the mild group. Gait fatigability rate was significantly correlated with physical fatigue, gait disability, and fall history. These findings suggest that sustained walking affects specific aspects of gait, which can be used as markers for fatigability in MS. This effect on gait depends on the degree of disability, and may increase fall risk in pwMS. To more fully understand and monitor correlates that reflect everyday walking in pwMS, multiple domains of gait should be quantified.

Three distinct physical behavior types in fatigued patients with multiple sclerosis

Background

Multiple sclerosis often leads to fatigue and changes in physical behavior (PB). Changes in PB are often assumed as a consequence of fatigue, but effects of interventions that aim to reduce fatigue by improving PB are not sufficient. Since the heterogeneous nature of MS related symptoms, levels of PB of fatigued patients at the start of interventions might vary substantially. Better understanding of the variability by identification of PB subtypes in fatigued patients may help to develop more effective personalized rehabilitation programs in the future. This study aimed to identify PB subtypes in fatigued patients with multiple sclerosis based on multidimensional PB outcome measures.

Methods

Baseline accelerometer (Actigraph) data, demographics and clinical characteristics of the TREFAMS-ACE participants (n = 212) were used for secondary analysis. All patients were ambulatory and diagnosed with severe fatigue based on a score of ≥35 on the fatigue subscale of the Checklist Individual Strength (CIS20r). Fifteen PB measures were used derived from 7 day measurements with an accelerometer. Principal component analysis was performed to define key outcome measures for PB and two-step cluster analysis was used to identify PB types.

Results

Analysis revealed five key outcome measures: percentage sedentary behavior, total time in prolonged moderate-to-vigorous physical activity, number of sedentary bouts, and two types of change scores between day parts (morning, afternoon and evening). Based on these outcomes three valid PB clusters were derived.

Conclusions

Patients with severe MS-related fatigue show three distinct and homogeneous PB subtypes. These PB subtypes, based on a unique set of PB outcome measures, may offer an opportunity to design more individually-tailored interventions in rehabilitation.

Trial registration

Clinical trial registration no ISRCTN 82353628, ISRCTN 69520623 and ISRCTN 58583714.

Electronic supplementary material

The online version of this article (10.1186/s12984-019-0573-1) contains supplementary material, which is available to authorized users.

Ecological validity of walking capacity tests following rehabilitation in people with multiple sclerosis

Background

Walking capacity tests are commonly used to evaluate interventions aiming at reducing walking impairment in people with multiple sclerosis (pwMS). However, their ecological validity has recently been questioned. The aim of the present study was to investigate the ecological validity of the 2- and 6-minutes walking tests (2MWT and 6MWT) and the timed 25-foot walk (T25FW) after 28 days of multidisciplinary inpatient rehabilitation (MIR) in pwMS using accelerometry.

Methods

PwMS wore an accelerometer on 7 consecutive days within a 14-day period prior to MIR, performed 2/6MWT and T25FW at the beginning and at the end of MIR, followed by another 7 consecutive days of accelerometry.

Results

Significant improvements in 2/6MWT and T25FW after MIR in a cohort of 76 pwMS (mean age = 47.9, SD 8.3 years) were overall correlated to a significant gain in everyday life mobility (total steps/day). However, the correlation was strongly dependent on pre-existing walking disability defined by EDSS and only pwMS with “mild” walking impairment (EDSS 2–3.5) were able to transfer benefits measurable by walking capacity tests into improved everyday life mobility, while pwMS with “moderate to severe” walking disability (EDSS 4–6.5) were not.

Conclusion

Ecological validity of changes in walking capacity tests following MIR is strongly dependent on pre-existing walking impairment.

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

Background

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

Methods

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

Results

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

Conclusions

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

Trial registration

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

The Role of Wearable Devices in Multiple Sclerosis

Multiple sclerosis (MS) is the most common neurological disorder in young adults. The prevalence of walking impairment in people with MS (pwMS) is estimated between 41% and 75%. To evaluate the walking capacity in pwMS, the patient reported outcomes (PROs) and performance-based tests (i.e., the 2-minute walk test, the 6-minute walk test, the Timed 25-Foot Walk Test, the Timed Up and Go Test, and the Six Spot Step Test) could be used. However, some studies point out that the results of both performance-based tests and objective measures (i.e., by accelerometer) could not reflect patient reports of walking performance and impact of MS on daily life. This review analyses different motion sensors embedded in smartphones and motion wearable device (MWD) that can be useful to measure free-living walking behavior, to evaluate falls, fatigue, sedentary lifestyle, exercise, and quality of sleep in everyday life of pwMS. Caveats and limitations of MWD such as variable accuracy, user adherence, power consumption and recharging, noise susceptibility, and data management are discussed as well.

Inertial sensors versus standard systems in gait analysis: a systematic review and meta-analysis

INTRODUCTION

The increasing popularity of inertial sensors in clinical practice is not supported by precise information on their reliability or guidelines for their use in rehabilitation. The authors investigated the state of the literature concerning the use of inertial sensors for gait analysis in both healthy and pathological adults comparing traditional systems. Furthermore, trying to define directions for clinicians.

EVIDENCE ACQUISITION

In accordance with the PRISMA statement, authors searched in PubMed, Web of Science and Scopus all paper published from January 1st, 2005 until December 31st, 2017. They included both healthy and pathological adults' subjects as population, wearable or inertial sensors used for gait analysis and compared with classical gait analysis performed in a Motion Lab as intervention and comparison, gait parameters as outcomes. Considering the methodological quality, authors focused on: sample; description of the study; type of gait analysis used for comparison; type of sensor; sensor placement on the body; gait task requested.

EVIDENCE SYNTHESIS

From a total of 888 articles, 16 manuscripts were selected and 7 of them were considered for meta-analysis for different gait parameters. Demographic data, tested devices, reference systems, test procedures and outcomes were analyzed.

CONCLUSIONS

Our results show a good agreement between inertial sensors and classical gait analysis for some gait parameters, supporting their use as a solution for capturing kinematic information over an extended space and time and even outside a laboratory in real-life conditions. Authors can support the use of portable inertial sensors for a practical gait analysis in clinical setting with good reliability. It will then be the experience of the clinician to direct the decision-making process.

e-Health and multiple sclerosis: An update

e-Health (or digital healthcare) is becoming increasingly relevant in multiple sclerosis (MS) clinical management. We aim to review and discuss current status and future perspective of e-health in people with multiple sclerosis (pwMS). The first part of this review describes how information on MS can be conveyed through the Web and digital media. The second part illustrates recent advances in digital technology that can improve clinical management and in motor and cognitive rehabilitation of pwMS. Finally, this review advocates future development of the "digital case manager" as a new figure to coordinate clinical management and care of pwMS. The digital revolution is changing the medical approach to MS in terms of information conveying and sharing, rehabilitation, and healthcare management.

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.

Clinical outcome measures for progressive MS trials

Treatment options for progressive multiple sclerosis remain the main unmet need of the field. As the understanding of multiple sclerosis (MS) pathogenesis improves, new pathways and molecules will be tested for potential reparative, remyelinating, or neuroprotective effects. The clinical outcomes used will determine successful demonstration of beneficial treatment effects to regulatory agencies, clinicians, and persons with MS. This review focuses on clinical outcome measures including the Expanded Disability Status Scale, Multiple Sclerosis Functional Composite, and novel composite measures of disability. The paper also covers cognitive outcomes and screening tests for use in clinical trials. The growing importance of patient-reported outcomes and their suitability for clinical trials is also presented. The review aims to create consensus in regard to these topics and suggestions for future research.

Real-world walking in multiple sclerosis: Separating capacity from behavior

BACKGROUND

Habitual physical activity (HPA) measurement addresses the impact of MS on real-world walking, yet its interpretation is confounded by the competing influences of MS-associated walking capacity and physical activity behaviors.

OBJECTIVE

To develop specific measures of MS-associated walking capacity through statistically sophisticated HPA analysis, thereby more precisely defining the real-world impact of disease.

METHODS

Eighty-eight MS and 38 control subjects completed timed walks and patient-reported outcomes in clinic, then wore an accelerometer for 7days. HPA was analyzed with several new statistics, including the maximum step rate (MSR) and habitual walking step rate (HWSR), along with conventional methods, including average daily steps. HPA statistics were validated using clinical walking outcomes.

RESULTS

The six-minute walk (6MW) step rate correlated most strongly with MSR (r=0.863, p<10^-25) and HWSR (r=0.815, p<10^-11) rather than average daily steps (r=0.676, p<10^-11). The combination of MSR and HWSR correlated more strongly with the 6MW step rate than either measure alone (r=0.884, p<10^-14). The MSR overestimated the 6MW step rate (μ=10.4, p<10^-7), whereas the HWSR underestimated it (μ=-18.2, p<10^-19).

CONCLUSIONS

Conventional HPA statistics are poor measures of capacity due to variability in activity behaviors. The MSR and HWSR are valid, specific measures of real-world capacity which capture subjects' highest step rate and preferred step rate, respectively.

Wearable biosensors to monitor disability in multiple sclerosis

Purpose of review

Biosensors capable of measuring physiologic and kinetic parameters associated with disability are being applied to the study of people with multiple sclerosis (MS). We review the use of biosensors in people with MS with an emphasis on measuring/monitoring disability and understanding knowledge gaps between biosensor data and clinical care.

Recent findings

Accelerometers are available to the public and may be able to help the clinician understand a patient's degree of disability. Further studies with wearable biosensors capable of measuring other physiologic features, such as vital signs, are needed and are likely to contribute to our understanding of MS.

Summary

Wearable biosensors can improve our understanding of disability, response to treatment, and natural history of MS.

Mobility measures differentiate falls risk status in persons with multiple sclerosis: An exploratory study

BACKGROUND

Falls are of great concern among persons with multiple sclerosis (MS).

OBJECTIVE

To examine differences in metrics of mobility, postural control, and cognition in persons with MS with distinct fall risk status; and to investigate predictors of fall risk group membership using discriminant analysis.

METHODS

Forty-seven persons with MS completed the Activities-Balance Confidence (ABC) Scale and underwent a battery of assessments of mobility, balance, and cognition. Participants further wore an accelerometer for 7 days as an assessment of steps/day. Participants were allocated into fall risk groups based on ABC scale scores (increased fall risk (IFR); and normal fall risk (NFR)). We examined univariate differences between groups using ANOVA, and discriminant function analysis (DFA) identified the significant multivariate predictors of FR status.

RESULTS

After controlling for disability level, the IFR group had significantly (p < 0.05) worse scores on measures of mobility (i.e., MSWS-12, 6 MW, and steps/day) compared to the NFR group. DFA identified MSWS-12 and 6 MW scores as significant (p < 0.05) predictors of fall risk group membership. Those two variables collectively explained 55% of variance in fall risk grouping.

CONCLUSIONS

The findings suggest that mobility should be the focus of rehabilitation programs in persons with MS, especially for those at IFR.

The Performance Scales disability measure for multiple sclerosis: use and sensitivity to clinically important differences

BACKGROUND

In 1993, the Performance Scales© was created to assess multi-dimensional disability in multiple sclerosis (MS). This tool has been used in a variety of settings and study designs internationally. The present work provides an overview of the history and psychometric characteristics of the Performance Scales©, reviews its use over the past two decades, and summarizes its responsiveness to subgroup differences.

METHODS

A Google Scholar and Ovid search yielded 230 articles citing the Performance Scales©, of which 82 studies used the tool in empirical research. Twelve articles provided sufficient information to enable computation of effect sizes. Forest plots were used to show effect sizes for the overall summary score and by domain by patient demographics, MS disease trajectory, and treatment adherence.

RESULTS

The Performance Scales© evidenced sensitivity to clinically important differences by disease trajectory and age (for selected domains). In contrast, groups distinguished by patient adherence to disease-modifying therapies and ethnicity were relatively small.

CONCLUSIONS

The Performance Scales© has been used in a large number of studies since its development, suggesting that this psychometrically sound tool is acknowledged to be a useful tool for MS clinical research. It is recommended that future work include the entire measure, so that the whole-person impact of MS can be characterized and considered in MS outcome research.

Minimum number of days required for a reliable estimate of daily step count and energy expenditure, in people with MS who walk unaided

BACKGROUND AND PURPOSE

The purpose of this study was to examine the minimum number of days needed to reliably estimate daily step count and energy expenditure (EE), in people with multiple sclerosis (MS) who walked unaided.

METHODS

Seven days of activity monitor data were collected for 26 participants with MS (age=44.5±11.9years; time since diagnosis=6.5±6.2years; Patient Determined Disease Steps=≤3). Mean daily step count and mean daily EE (kcal) were calculated for all combinations of days (127 combinations), and compared to the respective 7-day mean daily step count or mean daily EE using intra-class correlations (ICC), the Generalizability Theory and Bland-Altman.

RESULTS

For step count, ICC values of 0.94-0.98 and a G-coefficient of 0.81 indicate a minimum of any random 2-day combination is required to reliably calculate mean daily step count. For EE, ICC values of 0.96-0.99 and a G-coefficient of 0.83 indicate a minimum of any random 4-day combination is required to reliably calculate mean daily EE. For Bland-Altman analyses all combinations of days, bar single day combinations, resulted in a mean bias within ±10%, when expressed as a percentage of the 7-day mean daily step count or mean daily EE.

CONCLUSIONS

A minimum of 2days for step count and 4days for EE, regardless of day type, is needed to reliably estimate daily step count and daily EE, in people with MS who walk unaided.

Validity of the timed 25-foot walk as an ambulatory performance outcome measure for multiple sclerosis

The Multiple Sclerosis Outcome Assessments Consortium (MSOAC) includes representatives from advocacy organizations, Food and Drug Administration (FDA), European Medicines Agency (EMA), National Institute of Neurological Disorders and Stroke (NINDS), academic institutions, and industry partners along with persons living with multiple sclerosis (MS). One of the MSOAC goals is acceptance and qualification by regulators of performance outcomes that are highly reliable and valid, practical, cost-effective, and meaningful in MS. This article addresses the history, application, and psychometric properties of one such MSOAC metric of ambulation or walking namely, the timed 25-foot walk (T25FW). The T25FW has strong reliability over both brief and long periods of time in MS across a large range of disability levels. The outcome of walking speed from the T25FW has obvious real-world relevance and has correlated strongly with other measures of walking and lower extremity function. The T25FW is responsive for capturing intervention effects in pharmacological and rehabilitation trials and has an established value for capturing clinically meaningful change in ambulation. Directions for future research involve validating clinically meaningful improvements on the T25FW as well as determining whether 20% change is clinically meaningful across the disability spectrum. Researchers might further consider synchronizing accelerometers and motion sensors with the T25FW for capturing walking speed in everyday life and the patient's real environment.

Monitoring gait in multiple sclerosis with novel wearable motion sensors

BACKGROUND

Mobility impairment is common in people with multiple sclerosis (PwMS) and there is a need to assess mobility in remote settings. Here, we apply a novel wireless, skin-mounted, and conformal inertial sensor (BioStampRC, MC10 Inc.) to examine gait characteristics of PwMS under controlled conditions. We determine the accuracy and precision of BioStampRC in measuring gait kinematics by comparing to contemporary research-grade measurement devices.

METHODS

A total of 45 PwMS, who presented with diverse walking impairment (Mild MS = 15, Moderate MS = 15, Severe MS = 15), and 15 healthy control subjects participated in the study. Participants completed a series of clinical walking tests. During the tests participants were instrumented with BioStampRC and MTx (Xsens, Inc.) sensors on their shanks, as well as an activity monitor GT3X (Actigraph, Inc.) on their non-dominant hip. Shank angular velocity was simultaneously measured with the inertial sensors. Step number and temporal gait parameters were calculated from the data recorded by each sensor. Visual inspection and the MTx served as the reference standards for computing the step number and temporal parameters, respectively. Accuracy (error) and precision (variance of error) was assessed based on absolute and relative metrics. Temporal parameters were compared across groups using ANOVA.

RESULTS

Mean accuracy±precision for the BioStampRC was 2±2 steps error for step number, 6±9ms error for stride time and 6±7ms error for step time (0.6-2.6% relative error). Swing time had the least accuracy±precision (25±19ms error, 5±4% relative error) among the parameters. GT3X had the least accuracy±precision (8±14% relative error) in step number estimate among the devices. Both MTx and BioStampRC detected significantly distinct gait characteristics between PwMS with different disability levels (p<0.01).

CONCLUSION

BioStampRC sensors accurately and precisely measure gait parameters in PwMS across diverse walking impairment levels and detected differences in gait characteristics by disability level in PwMS. This technology has the potential to provide granular monitoring of gait both inside and outside the clinic.