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

Walking performance differs between people with multiple sclerosis who perform distinct types of exercise

Aim: To determine whether walking performance differed between people with multiple sclerosis (MS) who performed distinct types, volumes and intensities of exercise.Materials & methods: Forty-five people with relapsing-remitting MS performed two trials of the 2-min walk test, one at a preferred speed and another at a fast speed. Gait metrics were measured by wireless inertial sensors. Participants reported the type (aerobic, resistance), volume and intensity of exercise performed.Results: Walking speed reserve and gait variability were better in participants who performed combined aerobic and resistance exercises compared with those who performed aerobic-only exercise.Conclusion: Walking performance differs in people with mild MS disability based on the type and volume of exercise performed.

Innovative multidimensional gait evaluation using IMU in multiple sclerosis: introducing the semiogram

Background

Quantifying gait using inertial measurement units has gained increasing interest in recent years. Highly degraded gaits, especially in neurological impaired patients, challenge gait detection algorithms and require specific segmentation and analysis tools. Thus, the outcomes of these devices must be rigorously tested for both robustness and relevancy in order to recommend their routine use. In this study, we propose a multidimensional score to quantify and visualize gait, which can be used in neurological routine follow-up. We assessed the reliability and clinical coherence of this method in a group of severely disabled patients with progressive multiple sclerosis (pMS), who display highly degraded gait patterns, as well as in an age-matched healthy subjects (HS) group.

Methods

Twenty-two participants with pMS and nineteen HS were included in this 18-month longitudinal follow-up study. During the follow-up period, all participants completed a 10-meter walk test with a U-turn and back, twice at M0, M6, M12, and M18. Average speed and seven clinical criteria (sturdiness, springiness, steadiness, stability, smoothness, synchronization, and symmetry) were evaluated using 17 gait parameters selected from the literature. The variation of these parameters from HS values was combined to generate a multidimensional visual tool, referred to as a semiogram.

Results

For both cohorts, all criteria showed moderate to very high test-retest reliability for intra-session measurements. Inter-session quantification was also moderate to highly reliable for all criteria except smoothness, which was not reliable for HS participants. All partial scores, except for the stability score, differed between the two populations. All partial scores were correlated with an objective but not subjective quantification of gait severity in the pMS population. A deficit in the pyramidal tract was associated with altered scores in all criteria, whereas deficits in cerebellar, sensitive, bulbar, and cognitive deficits were associated with decreased scores in only a subset of gait criteria.

Conclusions

The proposed multidimensional gait quantification represents an innovative approach to monitoring gait disorders. It provides a reliable and informative biomarker for assessing the severity of gait impairments in individuals with pMS. Additionally, it holds the potential for discriminating between various underlying causes of gait alterations in pMS.

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

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

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

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

Turning and multitask gait unmask gait disturbance in mild-to-moderate multiple sclerosis: Underlying specific cortical thinning and connecting fibers damage

Multiple sclerosis (MS) causes gait and cognitive impairments that are partially normalized by compensatory mechanisms. We aimed to identify the gait tasks that unmask gait disturbance and the underlying neural correlates in MS. We included 25 patients with MS (Expanded Disability Status Scale score: median 2.0, interquartile range 1.0-2.5) and 19 healthy controls. Fast-paced gait examinations with inertial measurement units were conducted, including straight or circular walking with or without cognitive/motor tasks, and the timed up and go test (TUG). Receiver operating characteristic curve analysis was performed to distinguish both groups by the gait parameters. The correlation between gait parameters and cortical thickness or fractional anisotropy values was examined by using three-dimensional T1-weighted imaging and diffusion tensor imaging, respectively (corrected p < .05). Total TUG duration (>6.0 s, sensitivity 88.0%, specificity 84.2%) and stride velocity during cognitive dual-task circular walking (<1.12 m/s, 84.0%, 84.2%) had the highest discriminative power of the two groups. Deterioration of these gait parameters was correlated with thinner cortical thickness in regional areas, including the left precuneus and left temporoparietal junction, overlapped with parts of the default mode network, ventral attention network, and frontoparietal network. Total TUG duration was negatively correlated with fractional anisotropy values in the deep cerebral white matter areas. Turning and multitask gait may be optimal to unveil partially compensated gait disturbance in patients with mild-to-moderate MS through dynamic balance control and multitask processing, based on the structural damage in functional networks.

An Algorithm for Accurate Marker-Based Gait Event Detection in Healthy and Pathological Populations During Complex Motor Tasks

There is growing interest in the quantification of gait as part of complex motor tasks. This requires gait events (GEs) to be detected under conditions different from straight walking. This study aimed to propose and validate a new marker-based GE detection method, which is also suitable for curvilinear walking and step negotiation. The method was first tested against existing algorithms using data from healthy young adults (YA, n = 20) and then assessed in data from 10 individuals from the following five cohorts: older adults, chronic obstructive pulmonary disease, multiple sclerosis, Parkinson’s disease, and proximal femur fracture. The propagation of the errors associated with GE detection on the calculation of stride length, duration, speed, and stance/swing durations was investigated. All participants performed a variety of motor tasks including curvilinear walking and step negotiation, while reference GEs were identified using a validated methodology exploiting pressure insole signals. Sensitivity, positive predictive values (PPV), F1-score, bias, precision, and accuracy were calculated. Absolute agreement [intraclass correlation coefficient (ICC2,1)] between marker-based and pressure insole stride parameters was also tested. In the YA cohort, the proposed method outperformed the existing ones, with sensitivity, PPV, and F1 scores ≥ 99% for both GEs and conditions, with a virtually null bias (&lt;10 ms). Overall, temporal inaccuracies minimally impacted stride duration, length, and speed (median absolute errors ≤1%). Similar algorithm performances were obtained for all the other five cohorts in GE detection and propagation to the stride parameters, where an excellent absolute agreement with the pressure insoles was also found (ICC2,1=0.817− 0.999). In conclusion, the proposed method accurately detects GE from marker data under different walking conditions and for a variety of gait impairments.

Longitudinal relationships between disability and gait characteristics in people with MS

Longitudinal data are vital in order to understand intra individual gait changes with the progression of multiple sclerosis (MS). Therefore, the primary aim of this study was to explore the relationship between changes in disability with changes in major spatio-temporal parameters of gait in people with MS (PwMS). PwMS (n = 83) completed two gait assessments performed at separate time points (M1, M2). For each individual, the absolute difference between the Expanded Disability Status Scale (EDSS) score, key spatio-temporal parameters of gait, Falls Efficacy Scale International (FES-I), and the 12-item Multiple Sclerosis Walking Scale (MSWS-12), were calculated. The mean time difference between M1 and M2 was 2.5 (SD = 1.7) years. At M2, PwMS presented with shorter strides, a wider base of support, increased perceived mobility difficulties and fear of falling compared with M1. According to the odds ratio (OR) analysis, the odds of experiencing an increase in the EDSS score was significantly higher once the MSWS-12 score increased at M2 compared with M1 (OR = 7.930, p = 0.004). This observation was highlighted specifically in people with mild-moderate MS (OR = 12.427, p < 0.001). The increase in the EDSS score was not associated with changes in key spatio-temporal parameters of gait. The present study provides a better understanding of gait and disease progression in PwMS, highlighting the significant role of the MSWS-12.

Reflex Locomotion Therapy for Balance, Gait, and Fatigue Rehabilitation in Subjects with Multiple Sclerosis

This study evaluates the effects of a rehabilitation program based on reflex locomotion therapy (RLT) on balance, gait, and fatigue in patients with multiple sclerosis (MS). Twenty-three patients diagnosed with MS participated in this study. Reversal design was carried out. The assessment tools included the Berg Balance Scale (BBS), the Performance Oriented Mobility Assessment (POMA), the Fatigue Severity Scale (FSS) and the instrumental analysis of the gait recorded by Vicon Motion System^®. We analyzed spatio-temporal parameters and kinematic variables of the hip, knee, and ankle joints. Additionally, the Client Satisfaction Questionnaire (CSQ-8) was administrated. We did find a significant improvement in balance and gait tools after the RLT period. Regarding instrumental analysis, the statistical analysis of spatio-temporal parameters showed a significant improvement in stride length, double support, and velocity after the RLT period. Concerning kinematic parameters, the analysis showed improvements in hip and knee range of motion (ROM) after RLT period. RLT could improve gait and balance in patients with MS. The patients reported a high level of satisfaction with the therapy received.

Outcome measures used in trials on gait rehabilitation in multiple sclerosis: A systematic literature review

Background

Multiple Sclerosis (MS) is associated with impaired gait and a growing number of clinical trials have investigated efficacy of various interventions. Choice of outcome measures is crucial in determining efficiency of interventions. However, it remains unclear whether there is consensus on which outcome measures to use in gait intervention studies in MS.

Objective

We aimed to identify the commonly selected outcome measures in randomized controlled trials (RCTs) on gait rehabilitation interventions in people with MS. Additional aims were to identify which of the domains of the International Classification of Functioning, Disability and Health (ICF) are the most studied and to characterize how outcome measures are combined and adapted to MS severity.

Methods

Pubmed, Cochrane Central, Embase and Scopus databases were searched for RCT studies on gait interventions in people living with MS according to PRISMA guidelines.

Results

In 46 RCTs, we identified 69 different outcome measures. The most used outcome measures were 6-minute walking test and the Timed Up and Go test, used in 37% of the analyzed studies. They were followed by gait spatiotemporal parameters (35%) most often used to inform on gait speed, cadence, and step length. Fatigue was measured in 39% of studies. Participation was assessed in 50% of studies, albeit with a wide variety of scales. Only 39% of studies included measures covering all ICF levels, and Participation measures were rarely combined with gait spatiotemporal parameters (only two studies).

Conclusions

Selection of outcome measures remains heterogenous in RCTs on gait rehabilitation interventions in MS. However, there is a growing consensus on the need for quantitative gait spatiotemporal parameter measures combined with clinical assessments of gait, balance, and mobility in RCTs on gait interventions in MS. Future RCTs should incorporate measures of fatigue and measures from Participation domain of ICF to provide comprehensive evaluation of trial efficacy across all levels of functioning.

A Preliminary Investigation of the Effects of Obstacle Negotiation and Turning on Gait Variability in Adults with Multiple Sclerosis

Many falls in persons with multiple sclerosis (PwMS) occur during daily activities such as negotiating obstacles or changing direction. While increased gait variability is a robust biomarker of fall risk in PwMS, gait variability in more ecologically related tasks is unclear. Here, the effects of turning and negotiating an obstacle on gait variability in PwMS were investigated. PwMS and matched healthy controls were instrumented with inertial measurement units on the feet, lumbar, and torso. Subjects completed a walk and turn (WT) with and without an obstacle crossing (OW). Each task was partitioned into pre-turn, post-turn, pre-obstacle, and post-obstacle phases for analysis. Spatial and temporal gait measures and measures of trunk rotation were captured for each phase of each task. In the WT condition, PwMS demonstrated significantly more variability in lumbar and trunk yaw range of motion and rate, lateral foot deviation, cadence, and step time after turning than before. In the OW condition, PwMS demonstrated significantly more variability in both spatial and temporal gait parameters in obstacle approach after turning compared to before turning. No significant differences in gait variability were observed after negotiating an obstacle, regardless of turning or not. Results suggest that the context of gait variability measurement is important. The increased number of variables impacted from turning and the influence of turning on obstacle negotiation suggest that varying tasks must be considered together rather than in isolation to obtain an informed understanding of gait variability that more closely resembles everyday walking.

Predicting Multiple Sclerosis From Gait Dynamics Using an Instrumented Treadmill: A Machine Learning Approach

OBJECTIVE

Multiple Sclerosis (MS) is a neurological condition which widely affects people 50-60 years of age. While clinical presentations of MS are highly heterogeneous, mobility limitations are one of the most frequent symptoms. This study examines a machine learning (ML) framework for identifying MS through spatiotemporal and kinetic gait features.

METHODS

In this study, gait data during self-paced walking on an instrumented treadmill from 20 persons with MS and 20 age, weight, height, and gender-matched healthy older adults (HOA) were obtained. We explored two strategies to normalize data and minimize dependence on subject demographics; size-normalization (standard body size-based normalization) and regress-normalization (regression-based normalization using scaling factors derived by regressing gait features on multiple subject demographics); and proposed an ML based methodology to classify individual strides of older persons with MS (PwMS) from healthy controls. We generalized both across different walking tasks and subjects.

RESULTS

We observed that regress-normalization improved the accuracy of identifying pathological gait using ML when compared to size-normalization. When generalizing from comfortable walking to walking while talking, gradient boosting machine achieved the optimal subject classification accuracy and AUC of 94.3 and 1.0, respectively and for subject generalization, a multilayer perceptron resulted in the best accuracy and AUC of 80% and 0.86, respectively, both with regression-normalized data.

CONCLUSION

The integration of gait data and ML may provide a viable patient-centric approach to aid clinicians in monitoring MS.

SIGNIFICANCE

The results of this study have future implications for the way regression normalized gait features may be clinically used to design ML-based disease prediction strategies and monitor disease progression in PwMS.

Toward a remote assessment of walking bout and speed: application in patients with multiple sclerosis

Gait speed as a powerful biomarker of mobility is mostly assessed in controlled environments, e.g. in the clinic. With wearable inertial sensors, gait speed can be estimated in an objective manner. However, most of the previous works have validated the gait speed estimation algorithms in clinical settings which can be different than the home assessments in which the patients demonstrate their actual performance. Moreover, to provide comfort for the users, devising an algorithm based on a single sensor setup is essential. To this end, the goal of this study was to develop and validate a new gait speed estimation method based on a machine learning approach to predict gait speed in both clinical and home assessments by a sensor on the lower back. Moreover, two methods were introduced to detect walking bouts during daily activities at home. We have validated the algorithms in 35 patients with multiple sclerosis as it often presents with mobility difficulties. Therefore, the robustness of the algorithm can be shown in an impaired or slow gait. Against silver standard multi-sensor references, we achieved a bias close to zero and a precision of 0.15 m/s for gait speed estimation. Furthermore, the proposed machine learning-based locomotion detection method had a median of 96.8% specificity, 93.0% sensitivity, 96.4% accuracy, and 78.6% F1-score in detecting walking bouts at home. The high performance of the proposed algorithm showed the feasibility of the unsupervised mobility assessment introduced in this study.

Gait Pattern in People with Multiple Sclerosis: A Systematic Review

The aim of the present systematic review was to describe the gait pattern in people with multiple sclerosis (MS) by compiling the main findings obtained from studies using three-dimensional capture systems of human movement. The search was carried out in PubMed, Web of Science, Physiotherapy Evidence Database (PEDro), and the Cumulative Index to Nursing and Allied Health (CINAHL) databases. Studies that used three-dimensional gait analysis systems and that analyzed spatiotemporal, kinematic, kinetic, or electromyographic parameters, were included. The quality of the studies was assessed using the Critical Review Form-Quantitative Studies scale. 12 articles were included with 523 (342 women and 181 men) people with a diagnosis of MS. The present work suggests that people with MS have a decrease in speed and stride length, as well as an increase in double-stance intervals during gait. Likewise, it is common to observe a decrease in hip extension during the stance period, a decrease in knee flexion in the swing period, a decrease in ankle dorsiflexion in the initial contact and a decrease in ankle plantar flexion during the pre-swing phase. The subjects with MS decrease the hip extensor moment and the ankle power during the stance period of walking.

Axonal loss in major sensorimotor tracts is associated with impaired motor performance in minimally disabled multiple sclerosis patients

Multiple sclerosis is a neuroinflammatory disease of the CNS that is associated with significant irreversible neuro-axonal loss, leading to permanent disability. There is thus an urgent need for in vivo markers of axonal loss for use in patient monitoring or as end-points for trials of neuroprotective agents. Advanced diffusion MRI can provide markers of diffuse loss of axonal fibre density or atrophy within specific white matter pathways. These markers can be interrogated in specific white matter tracts that underpin important functional domains such as sensorimotor function. This study aimed to evaluate advanced diffusion MRI markers of axonal loss within the major sensorimotor tracts of the brain, and to correlate the degree of axonal loss in these tracts to precise kinematic measures of hand and foot motor control and gait in minimally disabled people with multiple sclerosis. Twenty-eight patients (Expanded Disability Status Scale < 4, and Kurtzke Functional System Scores for pyramidal and cerebellar function ≤ 2) and 18 healthy subjects underwent ultra-high field 7 Tesla diffusion MRI for calculation of fibre-specific measures of axonal loss (fibre density, reflecting diffuse axonal loss and fibre cross-section reflecting tract atrophy) within three tracts: cortico-spinal tract, interhemispheric sensorimotor tract and cerebello-thalamic tracts. A visually guided force-matching task involving either the hand or foot was used to assess visuomotor control, and three-dimensional marker-based video tracking was used to assess gait. Fibre-specific axonal markers for each tract were compared between groups and correlated with visuomotor task performance (force error and lag) and gait parameters (stance, stride length, step width, single and double support) in patients. Patients displayed significant regional loss of fibre cross-section with minimal loss of fibre density in all tracts of interest compared to healthy subjects (family-wise error corrected p-value < 0.05), despite relatively few focal lesions within these tracts. In patients, reduced axonal fibre density and cross-section within the corticospinal tracts and interhemispheric sensorimotor tracts were associated with larger force tracking error and gait impairments (shorter stance, smaller step width and longer double support) (family-wise error corrected p-value < 0.05). In conclusion, significant gait and motor control impairments can be detected in minimally disabled people with multiple sclerosis that correlated with axonal loss in major sensorimotor pathways of the brain. Given that axonal loss is irreversible, the combined use of advanced imaging and kinematic markers could be used to identify patients at risk of more severe motor impairments as they emerge for more aggressive therapeutic interventions.

Influence of Multiple Sclerosis on Spatiotemporal Gait Parameters: A Systematic Review and Meta-Regression

OBJECTIVE

To quantify the effect of multiple sclerosis (MS) on spatiotemporal gait characteristics accounting for disability severity and fall classification.

DATA SOURCES

MEDLINE (1946-August 2018), Allied and Complementary Medicine Database (1985-2018 August), and PsycINFO (1806-August 2018) were searched for terms on MS and gait.

STUDY SELECTION

Dual independent screening was conducted to identify observational, cross-sectional studies that compared adults with MS grouped according to Expanded Disability Status Scale (EDSS) level or fall history, reported on spatiotemporal gait characteristics, and were published in English. The search retrieved 5891 results, of which 12 studies satisfied the inclusion criteria.

DATA EXTRACTION

Two authors worked independently to extract and verify data on publication details, study methodology, participant characteristics, gait outcomes, conclusions, and limitations. Risk of bias was assessed using the QualSyst critical appraisal tool. A random-effects meta-regression and meta-analysis were conducted on pooled data.

DATA SYNTHESIS

All studies received quality ratings of very good to excellent and collectively examined 1513 individuals with MS. With every 1-point increase in EDSS, significant changes (P<.05) were observed in gait speed (-0.12 m/s; 95% confidence interval (CI), 0.08-0.15), step length (-0.04 m; 95% CI, 0.03-0.05), step time (+0.04 seconds; 95% CI, 0.02-0.06), step time variability (+0.009 seconds; 95% CI, 0.003-0.016), stride time (+0.08 seconds; 95% CI, 0.03-0.12), cadence (-4.4 steps per minute; 95% CI, 2.3-6.4), stance phase duration (+0.8% gait cycle; 95% CI, 0.1-1.5), and double support time (+3.5% gait cycle; 95% CI, 1.5-5.4). Recent fallers exhibited an 18% (95% CI, 13%-23%) reduction in gait speed compared with nonfallers (P<.001).

CONCLUSIONS

This review provides the most accurate reference values to-date that can be used to assess the effectiveness of MS gait training programs and therapeutic techniques for individuals who differ on disability severity and fall classification. Some gait adaptations could be part of adopting a more cautious gait strategy and should be factored into the design of future interventions.

Fall-related functional impairments in patients with neurological gait disorder

Falls are common in patients with neurological disorders and are a primary cause of injuries. Nonetheless, fall-associated gait characteristics are poorly understood in these patients. Objective, quantitative gait analysis is an important tool to identify the principal fall-related motor characteristics and to advance fall prevention in patients with neurological disorders. Fall incidence was assessed in 60 subjects with different neurological disorders. Patients underwent a comprehensive set of functional assessments including instrumented gait analysis, computerized postural assessments and clinical walking tests. Determinants of falls were assessed by binary logistic regression analysis and receiver operator characteristics (ROC). The best single determinant of fallers was a step length reduction at slow walking speed reaching an accuracy of 67.2% (ROC AUC: 0.669; p = 0.027). The combination of 4 spatio-temporal gait parameters including step length and parameters of variability and asymmetry were able to classify fallers and non-fallers with an accuracy of 81.0% (ROC AUC: 0.882; p < 0.001). These findings suggest significant differences in specific spatio-temporal gait parameters between fallers and non-fallers among neurological patients. Fall-related impairments were mainly identified for spatio-temporal gait characteristics, suggesting that instrumented, objective gait analysis is an important tool to estimate patients' fall risk. Our results highlight pivotal fall-related walking deficits that might be targeted by future rehabilitative interventions that aim at attenuating falls.

Pilot trial of speed-intensive gait training on balance and walking in people with multiple sclerosis

Background/Aims

Diminished walking speed and endurance is commonly experienced by individuals with multiple sclerosis. Speed-intensive gait training has led to improvements in walking speed and endurance in other neurological populations; however, its effect in persons with multiple sclerosis is unknown. This pilot study examined the feasibility, safety and efficacy of speed-intensive gait training in a sample of people with multiple sclerosis.

Methods

A total of eight participants (five women, median Expanded Disability Status Scale 3.5) underwent a 6-week, twice weekly speed-intensive gait training programme. Walking speed and endurance, balance and fatigue were measured pre- and post-intervention.

Results

Speed-intensive gait training was feasible, with excellent adherence and safety. It proved effective, with improvements in walking speed (P=0.05), walking endurance (P=0.036) and balance (P=0.041) without an increase in fatigue.

Conclusions

The intermittent design of speed-intensive gait training may enable individuals with multiple sclerosis to achieve higher training volumes than traditional models. Although further study is warranted, rehabilitation clinicians should consider adding speed-intensive gait training as an intervention to improve walking and balance in this patient group.

Fampridine-induced changes in walking kinetics are associated with clinical improvements in patients with multiple sclerosis

Gait dysfunction is common in patients with multiple sclerosis (PwMS). Treatment with prolonged-release fampridine (PR-fampridine) improves walking ability in some PwMS. Associated fampridine-induced changes in the walking pattern are still poorly understood but may provide a better understanding of the mechanisms underlying the beneficial drug effects. 61 PwMS were treated with PR-fampridine in a randomized, monocentric, double-blind and placebo-controlled clinical trial with crossover design (FAMPKIN). Drug-induced improvements in walking speed (Timed-25-Foot Walk; T25FW) and endurance (6-Minute Walk Test; 6MWT) were quantified. In this sub-study of the FAMPKIN trial, fampridine-induced changes in kinetic gait patterns were analyzed by pressure-based foot print analysis during treadmill walking. Vertical ground reaction forces were analyzed during different gait phases. Kinetic data of 44 PwMS was eligible for analysis. During double-blind treatment with PR-fampridine, patients performed significantly better in the T25FW and 6MWT than during placebo treatment (p < 0.0001 for both). At the group level (n = 44), there were no significant changes of gait kinetics under PR-fampridine vs. placebo. However, we found relevant changes of walking kinetics regarding forces during loading, single limb and pre-swing phase in a patient sub-group (n = 8). Interestingly, this sub-group demonstrated superior responsiveness to PR-fampridine in the clinical walking tests compared to those patients without any fampridine-induced changes in kinetics (n = 36). Our results demonstrate fampridine-induced changes in gait kinetics in a sub-group of PwMS. These gait pattern changes were accompanied by improved clinical walking performance under PR-fampridine. These results shed some light on the biomechanical changes in walking patterns underlying enhanced fampridine-induced gait performance.

Hair cortisol concentration, cognitive, behavioral, and motor impairment in multiple sclerosis

Multiple sclerosis (MS) is an autoimmune neurodegenerative disease that is characterized by the demyelinated inflammatory processes that occur within the central nervous system. Hypothalamus-pituitary-adrenal axis (HPA axis) dysfunctions have been associated with the triggering or increase in MS symptoms. We thus aimed at evaluating motor and behavioral functions, planning skills, processing speed, and their relationship with stress through measuring hair cortisol concentration from patients with MS. The sample was composed of 40 volunteers that were clinically diagnosed with MS, along with 33 healthy adults. Evaluations included: Clinical Evaluation Form, Mini-Mental State Exam, Hamilton Depression Rating Scale, Multiple Sclerosis Functional Composite Measure, Expanded Disability Status Scale, Berg Balance Scale, Perceived Stress Scale, Zoo Map task, and a hair sample to analyze cortisol levels in the last 30 days. MS patients showed highly elevated hair cortisol levels in comparison to the control group (p = 0.048). All groups presented some degree of depressive and anxiety symptoms, aside from considerable perceived stress levels. The MS group presented deficits in gait, balance, manual skills and processing speed, and this was particularly so in individuals with moderate impairments when compared to control group (p < 0.001). Individuals with MS spent less time planning on ZooMap1 (p = 0.024) and made more mistakes (p < 0.001). No correlation was found between hair cortisol and the symptoms we assessed. However, depressive symptoms and anxiety were related to perceived stress, and higher hair cortisol suggests a change in levels in the HPA axis in MS. Nevertheless, future studies will be necessary to further understand how basal hair cortisol is related to MS symptoms.

Analysis of Spatial and Temporal Step Parameters During Crutch-Assisted Gait as a Dual-Task: A Pilot Study

The main objective was to analyze the changes in the spatial and temporal step parameters during a dual-task: walking with a forearm crutch to partially unload the body weight of the subject. The secondary objective was to determine the influence of the use of the crutch with the dominant or nondominant hand in the essential gait parameters. Seven healthy subjects performed gait without crutches (GWC) and unilateral assisted gait (UAG) with the crutch carried out by dominant hand (dominant crutch (DC)) and nondominant hand (nondominant crutch (NDC)). Gait was recorded using a Vicon System; the GCH System 2.0 and the GCH Control Software 1.0 controlled the loads. The variables were step length, step period, velocity, step width, and step angle. The Wilcoxon signed-rank test compared GWC and UAG while also analyzing the parameters measured for both legs with DC and NDC in general and in each subject. Wilcoxon test only found significant differences in 1 of the 15 general comparisons between both legs. In the analysis by subject, step length, step period, and velocity showed significant differences between GWC and UAG. These parameters obtained less differences in DC. The effect of a forearm crutch on UAG caused a reduction in step length and velocity, and an increase in step period. However, it did not entail changes in step angle and step width. UAG was more effective when the DC carried the crutch. The unloading of 10% body weight produced an assisted gait which closely matched GWC.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Influence of the load exerted over a forearm crutch in spatiotemporal step parameters during assisted gait: pilot study

BACKGROUND

Assisted gait with forearm crutches is frequently performed during the recovery of musculoskeletal injuries of the lower limb. The amount of body weight applied to the crutch or crutches depends on the pathology and the treatment phase. The transition from assisted gait with two crutches to a single crutch is usually recommended when the subject is able to load the 50% of the body weight upon the affected member. An altered assisted gait will cause biomechanic alterations and, therefore, longer treatments and relapses. The aim of this study was to analyze the influence of 10, 25 and 50% of body weight applied to a forearm crutch during a unilateral assisted gait in the spatial and temporal step parameters to determine the load that produces alterations in gait biomechanics and the load that does not.

METHODS

Eleven healthy subjects performed normal gait (NG) and assisted gait with a forearm crutch, in which the applied loads were: comfortable (C), 25 and 50% of their body weight. Vicon System was employed for gait recording. GCH System 2.0 and GCH Control Software 1.0 controlled the loads. The variables were: step length, step period, velocity, step width and step angle. Friedman test compared all the gait modalities: NG and the different loads. Wilcoxon signed-rank test analyzed ipsilateral and contralateral step parameters to the crutch globally and for each subject.

RESULTS

Friedman test showed significant differences between NG, C, 25 and 50%, especially for step period and velocity. Wilcoxon test had significant differences only in 4 of the 20 general comparisons between ipsilateral and contralateral steps to the crutch. In the analysis by subjects, step length, step period and velocity showed 79/132, 110/132 and 58/66 significant differences, respectively.

CONCLUSIONS

The increase in the load exerted over a forearm crutch produced an increase in the step period, accompanied by a reduction of step length and gait velocity. Step width and step angle were not modified. The unloading of 25 and 50% of body weight on a single crutch is incorrect from the biomechanical point of view. Two crutches should be employed when the body weight to unload exceeds 10%.

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

BACKGROUND

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

OBJECTIVE

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

DESIGN

This was a cross-sectional, observational study.

METHODS

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

RESULTS

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

LIMITATIONS

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

CONCLUSIONS

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

Effects of Rhythmic Auditory Cueing in Gait Rehabilitation for Multiple Sclerosis: A Mini Systematic Review and Meta-Analysis

Rhythmic auditory cueing has been shown to enhance gait performance in several movement disorders. The "entrainment effect" generated by the stimulations can enhance auditory motor coupling and instigate plasticity. However, a consensus as to its influence over gait training among patients with multiple sclerosis is still warranted. A systematic review and meta-analysis was carried out to analyze the effects of rhythmic auditory cueing in studies gait performance in patients with multiple sclerosis. This systematic identification of published literature was performed according to PRISMA guidelines, from inception until Dec 2017, on online databases: Web of science, PEDro, EBSCO, MEDLINE, Cochrane, EMBASE, and PROQUEST. Studies were critically appraised using PEDro scale. Of 602 records, five studies (PEDro score: 5.7 ± 1.3) involving 188 participants (144 females/40 males) met our inclusion criteria. The meta-analysis revealed enhancements in spatiotemporal parameters of gait i.e., velocity (Hedge's g: 0.67), stride length (0.70), and cadence (1.0), and reduction in timed 25 feet walking test (-0.17). Underlying neurophysiological mechanisms, and clinical implications are discussed. This present review bridges the gaps in literature by suggesting application of rhythmic auditory cueing in conventional rehabilitation approaches to enhance gait performance in the multiple sclerosis community.

Free-living and laboratory gait characteristics in patients with multiple sclerosis

Background

Wearable sensors offer the potential to bring new knowledge to inform interventions in patients affected by multiple sclerosis (MS) by thoroughly quantifying gait characteristics and gait deficits from prolonged daily living measurements. The aim of this study was to characterise gait in both laboratory and daily life conditions for a group of patients with moderate to severe ambulatory impairment due to MS. To this purpose, algorithms to detect and characterise gait from wearable inertial sensors data were also validated.

Methods

Fourteen patients with MS were divided into two groups according to their disability level (EDSS 6.5–6.0 and EDSS 5.5–5.0, respectively). They performed both intermittent and continuous walking bouts (WBs) in a gait laboratory wearing waist and shank mounted inertial sensors. An algorithm (W-CWT) to estimate gait events and temporal parameters (mean and variability values) using data recorded from the waist mounted sensor (Dynaport, Mc Roberts) was tested against a reference algorithm (S-REF) based on the shank-worn sensors (OPAL, APDM). Subsequently, the accuracy of another algorithm (W-PAM) to detect and classify WBs was also tested. The validated algorithms were then used to quantify gait characteristics during short (sWB, 5–50 steps), intermediate (iWB, 51–100 steps) and long (lWB, >100 steps) daily living WBs and laboratory walking. Group means were compared using a two-way ANOVA.

Results

W-CWT compared to S-REF showed good gait event accuracy (0.05–0.10 s absolute error) and was not influenced by disability level. It slightly overestimated stride time in intermittent walking (0.012 s) and overestimated highly variability of temporal parameters in both intermittent (17.5%–58.2%) and continuous walking (11.2%–76.7%). The accuracy of W-PAM was speed-dependent and decreased with increasing disability. The ANOVA analysis showed that patients walked at a slower pace in daily living than in the laboratory. In daily living gait, all mean temporal parameters decreased as the WB duration increased. In the sWB, the patients with a lower disability score showed, on average, lower values of the temporal parameters. Variability decreased as the WB duration increased.

Conclusions

This study validated a method to quantify walking in real life in people with MS and showed how gait characteristics estimated from short walking bouts during daily living may be the most informative to quantify level of disability and effects of interventions in patients moderately affected by MS. The study provides a robust approach for the quantification of recognised clinically relevant outcomes and an innovative perspective in the study of real life walking.

Profiling walking dysfunction in multiple sclerosis: characterisation, classification and progression over time

Gait dysfunction is a common and relevant symptom in multiple sclerosis (MS). This study aimed to profile gait pathology in gait-impaired patients with MS using comprehensive 3D gait analysis and clinical walking tests. Thirty-seven patients with MS walked on the treadmill at their individual, sustainable speed while 20 healthy control subjects walked at all the different patient's paces, allowing for comparisons independent of walking velocity. Kinematic analysis revealed pronounced restrictions in knee and ankle joint excursion, increased gait variability and asymmetry along with impaired dynamic stability in patients. The most discriminative single gait parameter, differentiating patients from controls with an accuracy of 83.3% (χ2 test; p = 0.0001), was reduced knee range of motion. Based on hierarchical cluster and principal component analysis, three principal pathological gait patterns were identified: a spastic-paretic, an ataxia-like, and an unstable gait. Follow-up assessments after 1 year indicated deterioration of walking function, particularly in patients with spastic-paretic gait patterns. Our findings suggest that impaired knee/ankle control is common in patients with MS. Personalised gait profiles and clustering algorithms may be promising tools for stratifying patients and to inform patient-tailored exercise programs. Responsive, objective outcome measures are important for monitoring disease progression and treatment effects in MS trials.

Effect of Training Exercises Incorporating Mechanical Devices on Fatigue and Gait Pattern in Persons with Relapsing-Remitting Multiple Sclerosis

Purpose: The aim of this study was to evaluate the effects of regular exercise incorporating mechanical devices on fatigue, gait pattern, mood, and quality of life in persons with relapsing-remitting multiple sclerosis (RRMS). Method: A total of 55 individuals with RRMS with an Expanded Disability Status Scale (EDSS) score of 0-4.5 and a Fatigue Severity Scale (FSS) score of 4.0 or more were randomly assigned to one of two exercise groups or a control group (n=18). Exercise programmes used aerobic, body weight, coordination, and balance exercises with either whole-body vibration (WBV; n=19; drop-outs, n=3) or the Balance Trainer system (n=18; drop-outs, n=4). Outcome measures included the FSS, Modified Fatigue Impact Scale (MFIS), Beck Depression Inventory (BDI-II), and Multiple Sclerosis International Quality of Life (MusiQoL). Spatiotemporal gait parameters were assessed using the GAITRite electronic walkway. Pre- and post-intervention assessments were performed by a blinded assessor. Intra- and inter-group analysis was performed, using the paired-samples t-test, by calculating the effect size with Cohen's d analysis and one-way analysis of variance, respectively. Results: Significant improvements in fatigue and mood were identified for both intervention groups (p<0.05). Gait parameters also improved significantly in the WBV group: velocity and step length increased (12.8% and 6.5%, respectively; p<0.005), and step time, stance time, double support time, and step length asymmetry decreased (-5.3%, -1.4%, -5.9%, and -43.7%, respectively; p<0.005). Conclusions: The results of this study support the hypothesis that combined training programmes help to reduce fatigue and improve mood in persons with mild to moderate RRMS. WBV combined with a standard exercise programme significantly improves spatiotemporal gait parameters.

Do gait patterns differ in men and women with multiple sclerosis?

BACKGROUND

Multiple Sclerosis (MS) affects men and women differently from several points of view: prevalence, severity of cognitive impairments and disability accumulation. However, it is unknown whether ambulatory dysfunctions are sex-related. This study investigated the existence of differences in spatio-temporal and kinematic parameters of gait in men and women with MS using 3D gait analysis.

METHODS

Gait patterns of 60 people with MS (pwMS, 32F, 28M) with low to moderate disability (average Expanded Disability Status Scale score 3, range 1-5.5) who underwent a gait analysis in the period 2014-2017 were retrospectively analyzed to calculate spatio-temporal parameters of gait and kinematics in the sagittal plane at hip, knee and ankle joints.

RESULTS

Significant differences between the groups were found in kinematics of gait. In particular, men exhibited reduced ankle plantar-flexion, increased knee flexion and hip flexion. In contrast, no differences were found in spatio-temporal parameters normalized by considering individuals' anthropometry.

CONCLUSIONS

The findings of the present study highlight the need to investigate gait dysfunctions in pwMS taking sex into consideration. Such an approach might be useful not only in better understanding the pathophysiology of gait disturbances originated by MS, but also in supporting a better orientation of rehabilitative treatments.

Continuous In-Home Symptom and Mobility Measures for Individuals With Multiple Sclerosis: A Case Presentation

Gait impairment represents one of the most common and disabling symptoms of multiple sclerosis (MS). To identify which temporal or spatial parameters of gait could be used as outcome measures in interventional studies of individuals with MS with different levels of disability, we evaluated characteristics of these parameters in a case study of 3 participants with MS, using 1 case as an exemplar and the other participants as validation. A case study of an exemplar participant was conducted with a 67-year-old woman with secondary progressive MS served as exemplar, with 2 other participants (52 and 55 years old) as validation. The primary outcome measures we used were stride time, stride length, gait velocity, and daily symptoms. Stride length and velocity of gait decreased with increasing pain and fatigue. The step time was significantly longer later in the day, whereas the step length remained the same. Stride length and velocity are associated with the level of fatigue and pain, as well as the time of day. These characteristics and parameters of gait need to be considered in future studies of gait in MS, with particular attention to temporality of occurrence in persons with MS.

Evaluation of Clinical Gait Analysis parameters in patients affected by Multiple Sclerosis: Analysis of kinematics

BACKGROUND

Clinical Gait Analysis is commonly used to evaluate specific gait characteristics of patients affected by Multiple Sclerosis. The aim of this report is to present a retrospective cross-sectional analysis of the changes in Clinical Gait Analysis parameters in patients affected by Multiple Sclerosis.

METHODS

In this study a sample of 51 patients with different levels of disability (Expanded Disability Status Scale 2-6.5) was analyzed. We extracted a set of 52 parameters from the Clinical Gait Analysis of each patient and used statistical analysis and linear regression to assess differences among several groups of subjects stratified according to the Expanded Disability Status Scale and 6-Minutes Walking Test. The impact of assistive devices (e.g. canes and crutches) on the kinematics was also assessed in a subsample of patients.

FINDINGS

Subjects showed decreased range of motion at hip, knee and ankle that translated in increased pelvic tilt and hiking. Comparison between the two stratifications showed that gait speed during 6-Minutes Walking Test is better at discriminating patients' kinematics with respect to Expanded Disability Status Scale. Assistive devices were shown not to significantly impact gait kinematics and the Clinical Gait Analysis parameters analyzed.

INTERPRETATION

We were able to characterize disability-related trends in gait kinematics. The results presented in this report provide a small atlas of the changes in gait characteristics associated with different disability levels in the Multiple Sclerosis population. This information could be used to effectively track the progression of MS and the effect of different therapies.

A machine learning approach for gait speed estimation using skin-mounted wearable sensors: From healthy controls to individuals with multiple sclerosis

Gait speed is a powerful clinical marker for mobility impairment in patients suffering from neurological disorders. However, assessment of gait speed in coordination with delivery of comprehensive care is usually constrained to clinical environments and is often limited due to mounting demands on the availability of trained clinical staff. These limitations in assessment design could give rise to poor ecological validity and limited ability to tailor interventions to individual patients. Recent advances in wearable sensor technologies have fostered the development of new methods for monitoring parameters that characterize mobility impairment, such as gait speed, outside the clinic, and therefore address many of the limitations associated with clinical assessments. However, these methods are often validated using normal gait patterns; and extending their utility to subjects with gait impairments continues to be a challenge. In this paper, we present a machine learning method for estimating gait speed using a configurable array of skin-mounted, conformal accelerometers. We establish the accuracy of this technique on treadmill walking data from subjects with normal gait patterns and subjects with multiple sclerosis-induced gait impairments. For subjects with normal gait, the best performing model systematically overestimates speed by only 0.01 m/s, detects changes in speed to within less than 1%, and achieves a root-mean-square-error of 0.12 m/s. Extending these models trained on normal gait to subjects with gait impairments yields only minor changes in model performance. For example, for subjects with gait impairments, the best performing model systematically overestimates speed by 0.01 m/s, quantifies changes in speed to within 1%, and achieves a root-mean-square-error of 0.14 m/s. Additional analyses demonstrate that there is no correlation between gait speed estimation error and impairment severity, and that the estimated speeds maintain the clinical significance of ground truth speed in this population. These results support the use of wearable accelerometer arrays for estimating walking speed in normal subjects and their extension to MS patient cohorts with gait impairment.

Gait and balance deterioration over a 12-month period in multiple sclerosis patients with EDSS scores ≤ 3.0

BACKGROUND AND PURPOSE

It is not currently known whether gait and balance measures are responsive to deterioration of motor function in multiple sclerosis (MS) patients with low EDSS scores (≤3.0). The aim of this study was to quantify MS-related gait and balance deterioration over a 12-month period.

METHODS

Thirty-eight participants with MS (33 female, mean age: 41.1 ± 8.3 years), mean time since diagnosis 2.2 ± 4.1 years, EDSS score ≤3.0 and without clinical evidence of gait deterioration, were recruited. Participants performed walking trials and Functional and Lateral Reach Tests. Kinematics of the ankle and knee, and electromyography of the tibialis anterior and medial gastrocnemius muscles were also measured.

RESULTS

Three participants reported relapses with worsening EDSS scores and 4 non-relapsing participants had worse EDSS scores at 12 months. There were significant decreases in mean gait speed, stride length and balance scores, and a significant increase in double support. Marked changes in ankle kinematics, with decreased medial gastrocnemius activity were observed.

CONCLUSION

Gait and balance performance of non-disabled RRMS participants may progressively decline, even in the absence of both acute clinical relapse and change in clinical status measured by the EDSS.

Characterization of annual disease progression of multiple sclerosis patients: A population-based study

Background:

Previous research characterizing factors influencing multiple sclerosis (MS) disease progression has typically been based on time to disease milestones (Kaplan–Meier, Cox hazard regression, etc.). A limitation of these methods is the handling of the often large groups of patients not reaching the milestone.

Objective:

To characterize clinical factors influencing MS disease progression as annual transitions from each Expanded Disability Status Scale (EDSS).

Method:

The annual progression of 11,964 patients from the Swedish MS Registry was analysed with 10 multinomial logistic regressions, that is, one for transition from each full EDSS with explanatory variables age, sex, age at onset, time in current EDSS, highest prior EDSS, MS course and treatment.

Results:

All factors (except sex) investigated had statistically significant impacts on transitions from at least one EDSS. However, significance and size of the effect are dependent on the EDSS state of the patient. Greater age, longer time in a state, highest prior EDSS, having progressive MS and treatment had significant impacts, whereas age at onset had minor impact.

Conclusion:

Our study confirms that established factors associated with MS disease worsening in time to disease milestones also have impacts on annual progression. This approach adds granularity to what EDSS these factors have an influence.

Are static and functional balance abilities related in individuals with Multiple Sclerosis?

BACKGROUND

In people with Multiple Sclerosis (pwMS), balance assessment is essential in estimating the risk of falls, monitoring disease progression and verifying the effectiveness of rehabilitative treatment. Clinical tools and instrumental techniques are available for testing static and dynamic balance, but the relationship between such abilities is still not clear. Having information about this link would be important in properly planning the type and number of tests to administer.

METHODS

One hundred and six pwMS (Expanded Disability Status Scale, EDSS 0-6.5) stratified in three sub-groups (Class 1 EDSS 0-1.5, Class 2 EDSS 2-4 and Class 3 EDSS 4.5-6.5) and 42 healthy controls (HC) participated in the study. All underwent static posturography and instrumented Timed-Up-and-Go (TUG) performed using a wearable inertial sensor. Raw data were processed to extract postural sway features, overall duration of TUG and its main sub-phases (i.e. sit-to-stand, 180° turns and stand-to-sit).

RESULTS

All sway parameters of pwMS of Classes 2 and 3, as well as total TUG duration and time necessary to perform 180° turns, were found significantly higher than HC and Class 1 participants. However, poor correlations were found between sway and TUG parameters. When pwMS are grouped, small/moderate correlations (in the range 0.20-0.41) were found between all sway parameters and total TUG duration.

CONCLUSIONS

Static and dynamic balance in pwMS appear scarcely correlated, although both worsen as disability increases. This implies that they should be separately assessed using specific tests to have a complete view of postural control performance in MS.

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.

Bipedal Hopping Reveals Evidence of Advanced Neuromuscular Aging Among People With Mild Multiple Sclerosis

Measures of walking such as the timed 25-ft walk test (T25FWT) may not be able to detect subtle impairment in lower limb function among people with multiple sclerosis (MS). We examined bipedal hopping to determine to what extent people with mild (Expanded Disease Severity Scale ≤ 3.5) MS (n = 13) would differ compared to age-, gender-, and education-matched controls (n = 9) and elderly participants (n = 13; ≥ 70 years old). We estimated lower limb power (e.g., hop length, velocity), consistency (e.g., variability of hop length, time), and symmetry (ratio of left to right foot). Participants completed the T25FWT and, after a rest, they then hopped using both feet 4 times along the walkway. We found that although all groups scored below the 6 -s cutoff for T25FWT, the elderly group had significantly shorter hop lengths, more variability, and more asymmetry than the controls. The results of the MS group were not significantly different from the elderly or controls in most measures and most of their values fell between the control and elderly groups. Hop length, but not measures of walking predicted Expanded Disease Severity Scale score (R² = .38, p = .02). Bipedal hopping is a potentially useful measure of lower limb neuromuscular performance.

Are Modular Activations Altered in Lower Limb Muscles of Persons with Multiple Sclerosis during Walking? Evidence from Muscle Synergies and Biomechanical Analysis

Background: Persons with Multiple Sclerosis frequently have gait deficits that lead to diminished activities of daily living. Identification of motoneuron activity patterns may elucidate new insight into impaired locomotor coordination and underlying neural systems. The aim of the present study was to investigate muscle synergies, identified by motor modules and their activation profiles, in persons with Multiple Sclerosis (PwMS) during walking compared to those of healthy subjects (HS), as well as, exploring relationship of muscle synergies with walking ability of PwMS.

Methods: Seventeen PwMS walked at their natural speed while 12 HS walked at slower than their natural speeds in order to provide normative gait values at matched speeds (spatio-temporal, kinematic, and kinetic parameters and electromyography signals). Non-negative matrix factorization was used to identify muscle synergies from eight muscles. Pearson's correlation coefficient was used to evaluate the similarity of motor modules between PwMS and HS. To assess differences in module activations, each module's activation timing was integrated over 100% of gait cycle and the activation percentage was computed in six phases.

Results: Fifty-nine% of PwMS and 58% of HS had 4 modules while the remaining of both populations had 3 modules. Module 2 (related to soleus, medial, and lateral gastrocnemius primarily involved in mid and terminal stance) and Module 3 (related to tibialis anterior and rectus femoris primarily involved in early stance, and early and late swing) were comparable across all subjects regardless of synergies number. PwMS had shorter stride length, longer double support phase and push off deficit with respect to HS (p < 0.05). The alterations of activation timing profiles of specific modules in PwMS were associated with their walking deficits (e.g., the reduction of Module 2 activation percentage index in terminal stance, PwMS 35.55 ± 13.23 vs. HS 50.51 ± 9.13% p < 0.05, and the push off deficit, PwMS 0.181 ± 0.136 vs. HS 0.291 ± 0.062 w/kg p < 0.05).

Conclusion: During gait PwMS have synergies numbers similar to healthy persons. Their neurological deficit alters modular control through modifications of the timing activation profiles rather than module composition. These changes were associated with their main walking impairment, muscle weakness, and prolonged double support.

The use of laboratory gait analysis for understanding gait deterioration in people with multiple sclerosis

Laboratory gait analysis or three-dimensional gait analysis (3DGA), which uses motion capture, force plates and electromyography (EMG), has allowed a better understanding of the underlying mechanisms of gait deterioration in patients with multiple sclerosis (PwMS). This review will summarize the current knowledge on multiple sclerosis (MS)-related changes in kinematics (angles), kinetics (forces) and electromyographic (muscle activation) patterns and how these measures can be used as markers of disease progression. We will also discuss the potential causes of slower walking in PwMS and the implications for 3DGA. Finally, we will describe new technologies and methods that will increase precision and clinical utilization of 3DGA in PwMS. Overall, 3DGA studies have shown that functionality of the ankle joint is the most affected during walking and that compensatory actions to maintain a functional speed may be insufficient in PwMS. However, altered gait patterns may be a strategy to increase stability as balance is also affected in PwMS.

Gait characteristics according to pyramidal, sensory and cerebellar EDSS subcategories in people with multiple sclerosis

Walking deterioration is a common problem in people with multiple sclerosis (PwMS). However, there are only scarce data examining the contribution of specific neurological functional systems on gait performance in multiple sclerosis (MS). Therefore, the objective of the current study was to examine the differences in spatio-temporal parameters of gait according to the pyramidal, cerebellar and sensory functional systems. The cross-sectional study included 289 PwMS with mean disease duration of 8.0 (SD = 8.2) years. Spatio-temporal parameters of gait were studied using an electronic walkway. The sample pool was divided into six groups according to the scores of the pyramidal, cerebellar and sensory functional systems, derived from the expanded disability status scale data. Findings indicated that asymmetry of the step time and asymmetry of the single support were significantly elevated in the pyramidal group compared to the sensory group; 9.4 (SD = 10.6) vs. 3.1 (SD = 6.7), P value = 0.004; 9.3 (SD = 10.4) vs. 2.7 (2.1), P value = 0.001, respectively. Additionally, patients in the pure sensory group walked significantly faster with longer strides and less asymmetry compared to the pyramidal-cerebellar-sensory group. Moreover, patients in the sensory group walked with longer steps/strides and symmetry compared to the patients in the pyramidal-cerebellar group. This study confirms that pyramidal disorders are main contributors of gait impairments in the MS population. Furthermore, patients with sensory impairments have a relatively preserved gait pattern compared to patients affected by the pyramidal system.

Orthotic and therapeutic effect of functional electrical stimulation on fatigue induced gait patterns in people with multiple sclerosis

PURPOSE

To assess the orthotic and therapeutic effects of prolonged use of functional electrical stimulation (FES) on fatigue induced gait patterns in people with Multiple Sclerosis (MS).

METHOD

Thirteen people with MS completed 3D gait analysis with FES off and on, before and after a fatiguing 6-minute walk, at baseline and after 8 weeks of use of FES.

RESULTS

Eleven participants completed all testing. An orthotic effect on gait was not evident on first use of FES. However, therapeutic effects on gait after 8 weeks use were generally positive, including increases in walking speed due to improved neuromuscular control and power generated at the hip and ankle of the more affected limb. The action of FES alone was not sufficient to overcome all fatigue related deficits in gait but there was evidence 8 weeks use of FES can ameliorate some fatigue effects on lower limb kinetics, including benefits to ankle mechanics involved in generating power around push-off during stance.

CONCLUSIONS

Eight-weeks of FES can benefit the gait pattern of people with MS under non-fatigued and fatigued conditions. Implications for rehabilitation In some people with MS prolonged use of FES may be necessary before observing positive orthotic effects. Improvements in the neuromuscular control of the more affected lower limb may develop with prolonged use of FES in people with MS. Only some therapeutic benefits of FES are maintained during fatigued walking in people with MS. FES may be considered as a gait retraining device as well as an orthotic intervention for people with MS.

Gait variability across the disability spectrum in people with multiple sclerosis

BACKGROUND

An alternative method suggested to assess changes in walking in people with multiple sclerosis (PwMS) is evaluating gait variability. This is a credible option since gait variability reflects to some degree the quality of gait control.

OBJECTIVE

Examine the impact of disability on gait variability in PwMS.

METHODS

In this cross-sectional study, the data pool was divided into seven levels of disability based on the Expanded Disability Status Scale (EDSS) score, ranging from 0 to 6.5. Gait variability was studied using an electronic mat.

RESULTS

The final analysis included 381 PwMS (249 women); mean age 44.0years. Non-significant differences were observed between the EDSS subgroups at the lower end of the spectrum (EDSS 0-3.5) in all gait variability parameters. In contrast, PwMS in the EDSS 5.0-5.5 group demonstrated a significant increase in variability of step length (~151%), single support (~93%) and step time (142%) compared with those who scored 0-3.5. Moreover, participants in the EDSS 5.0-5.5 group had elevated step length variability compared to the EDSS 4.0-4.5 group (9.3 (S.E.=2.2) vs. 5.5 (S.E.=0.4), P-value=0.005).

CONCLUSION

We encourage clinicians to follow-up on the gait variability score as it appears to reflect mobility deterioration in PwMS.