Body-worn motion sensors detect balance and gait deficits in people with multiple sclerosis who have normal walking speed

Non-invasive brain stimulation to assess neurophysiologic underpinnings of lower limb motor impairment in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is a neuroinflammatory disease resulting in axonal demyelination and an amalgamation of symptoms which commonly result in decreased quality of life due to mobility dysfunction and limited participation in meaningful activities.

NEW METHOD

The use of non-invasive brain stimulation (NIBS) techniques, specifically transcranial magnetic and transcranial direct current stimulation, have been essential in understanding the pathophysiological decrements related to disease progression, particularly with regard to motor impairments. Although the research in this area has primarily focused on the upper extremities, new interest has arisen in understanding the neurophysiological underpinnings of lower limb impairment. Therefore, the purpose of this review is to: first, provide an overview of common NIBS techniques used to explore sensorimotor neurophysiology; second, summarize lower limb neuromuscular and mobility impairments typically observed in PwMS; third, review the current knowledge regarding interactions between TMS-assessed neurophysiology and lower limb impairments in PwMS; and fourth, provide recommendations for future NIBS studies based on current gaps in the literature.

RESULTS

PwMS exhibit reduced excitability and increased inhibitory neurophysiologic function which has been related to disease severity and lower limb motor impairments. Comparison with existing methods: Moreover, promising results indicate that the use of repetitive stimulation and transcranial direct current stimulation may prime neural adaptability and prove useful as a therapeutic tool in ameliorating lower limb impairments.

CONCLUSIONS

While these studies are both informative and promising, additional studies are necessary to be conclusive. As such, studies assessing objective measures of lower limb impairments associated with neurophysiological adaptations need further evaluation.

Smartphone- and Smartwatch-Based Remote Characterisation of Ambulation in Multiple Sclerosis During the Two-Minute Walk Test

Leveraging consumer technology such as smartphone and smartwatch devices to objectively assess people with multiple sclerosis (PwMS) remotely could capture unique aspects of disease progression. This study explores the feasibility of assessing PwMS and Healthy Control's (HC) physical function by characterising gait-related features, which can be modelled using machine learning (ML) techniques to correctly distinguish subgroups of PwMS from healthy controls. A total of 97 subjects (24 HC subjects, 52 mildly disabled (PwMSmild, EDSS [0-3]) and 21 moderately disabled (PwMSmod, EDSS [3.5-5.5]) contributed data which was recorded from a Two-Minute Walk Test (2MWT) performed out-of-clinic and daily over a 24-week period. Signal-based features relating to movement were extracted from sensors in smartphone and smartwatch devices. A large number of features (n = 156) showed fair-to-strong (R 0.3) correlations with clinical outcomes. LASSO feature selection was applied to select and rank subsets of features used for dichotomous classification between subject groups, which were compared using Logistic Regression (LR), Support Vector Machines (SVM) and Random Forest (RF) models. Classifications of subject types were compared using data obtained from smartphone, smartwatch and the fusion of features from both devices. Models built on smartphone features alone achieved the highest classification performance, indicating that accurate and remote measurement of the ambulatory characteristics of HC and PwMS can be achieved with only one device. It was observed however that smartphone-based performance was affected by inconsistent placement location (running belt versus pocket). Results show that PwMSmod could be distinguished from HC subjects (Acc. 82.2 ± 2.9%, Sen. 80.1 ± 3.9%, Spec. 87.2 ± 4.2%, F ₁ 84.3 ± 3.8), and PwMSmild (Acc. 82.3 ± 1.9%, Sen. 71.6 ± 4.2%, Spec. 87.0 ± 3.2%, F 1 75.1 ± 2.2) using an SVM classifier with a Radial Basis Function (RBF). PwMSmild were shown to exhibit HC-like behaviour and were thus less distinguishable from HC (Acc. 66.4 ± 4.5%, Sen. 67.5 ± 5.7%, Spec. 60.3 ± 6.7%, F ₁ 58.6 ± 5.8). Finally, it was observed that subjects in this study demonstrated low intra- and high inter-subject variability which was representative of subject-specific gait characteristics.

Cultural bias in motor function patterns: Potential relevance for predictive, preventive, and personalized medicine

Background

Quantification of motor performance has a promising role in personalized medicine by diagnosing and monitoring, e.g. neurodegenerative diseases or health problems related to aging. New motion assessment technologies can evolve into patient-centered eHealth applications on a global scale to support personalized healthcare as well as treatment of disease. However, uncertainty remains on the limits of generalizability of such data, which is relevant specifically for preventive or predictive applications, using normative datasets to screen for incipient disease manifestations or indicators of individual risks.

Objective

This study explored differences between healthy German and Japanese adults in the performance of a short set of six motor tests.

Methods

Six motor tasks related to gait and balance were recorded with a validated 3D camera system. Twenty-five healthy adults from Chiba, Japan, participated in this study and were matched for age, sex, and BMI to a sample of 25 healthy adults from Berlin, Germany. Recordings used the same technical setup and standard instructions and were supervised by the same experienced operator. Differences in motor performance were analyzed using multiple linear regressions models, adjusted for differences in body stature.

Results

From 23 presented parameters, five showed group-related differences after adjustment for height and weight (R ² between .19 and .46, p<.05). Japanese adults transitioned faster between sitting and standing and used a smaller range of hand motion. In stepping-in-place, cadence was similar in both groups, but Japanese adults showed higher knee movement amplitudes. Body height was identified as relevant confounder (standardized beta >.5) for performance of short comfortable and maximum speed walks. For results of posturography, regression models did not reveal effects of group or body stature.

Conclusions

Our results support the existence of a population-specific bias in motor function patterns in young healthy adults. This needs to be considered when motor function is assessed and used for clinical decisions, especially for personalized predictive and preventive medical purposes. The bias affected only the performance of specific items and parameters and is not fully explained by population-specific ethnic differences in body stature. It may be partially explained as cultural bias related to motor habits. Observed effects were small but are expected to be larger in a non-controlled cross-cultural application of motion assessment technologies with relevance for related algorithms that are being developed and used for data processing. In sum, the interpretation of individual data should be related to appropriate population-specific or even better personalized normative values to yield its full potential and avoid misinterpretation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-021-00236-3.

A Multifactorial Model of Multiple Sclerosis Gait and Its Changes Across Different Disability Levels

OBJECTIVE

Mobility assessment is critical in the clinical management of people with Multiple Sclerosis (pwMS). Instrumented gait analysis provides a plethora of metrics for quantifying concurrent factors contributing to gait deterioration. However, a gait model discriminating underlying features contributing to this deterioration is lacking in pwMS. This study aimed at developing and validating such a model.

METHODS

The gait of 24 healthy controls and 114 pwMS with mild, moderate, or severe disability was measured with inertial sensors on the shanks and lower trunk while walking for 6 minutes along a hospital corridor. Twenty out of thirty-six initially explored metrics computed from the sensor data met the quality criteria for exploratory factor analysis. This analysis provided the sought model, which underwent a confirmatory factor analysis before being used to characterize gait impairment across the three disability groups.

RESULTS

A gait model consisting of five domains (rhythm/variability, pace, asymmetry, and forward and lateral dynamic balance) was revealed by the factor analysis, which was able to highlight gait abnormalities across the disability groups: significant alterations in rhythm/variability-, asymmetry-, and pace-based features were present in the mild group, but these were more profound in the moderate and severe groups. Deterioration in dynamic balance-based features was only noted in pwMS with a moderate and severe disability.

CONCLUSION

A conceptual model of gait for disease-specific mobility assessment in pwMS was successfully developed and tested.

SIGNIFICANCE

The new model, built with metrics that represent gait impairment in pwMS, highlighted clinically relevant changes across different disability levels, including those with no clinically observable walking disability. This shows the clear potential as a monitoring biomarker in pwMS.

U-turn speed is a valid and reliable smartphone-based measure of multiple sclerosis-related gait and balance impairment

BACKGROUND

People living with multiple sclerosis (MS) experience impairments in gait and mobility, that are not fully captured with manually timed walking tests or rating scales administered during periodic clinical visits. We have developed a smartphone-based assessment of ambulation performance, the 5 U-Turn Test (5UTT), a quantitative self-administered test of U-turn ability while walking, for people with MS (PwMS).

RESEARCH QUESTION

What is the test-retest reliability and concurrent validity of U-turn speed, an unsupervised self-assessment of gait and balance impairment, measured using a body-worn smartphone during the 5UTT?

METHODS

76 PwMS and 25 healthy controls (HCs) participated in a cross-sectional non-randomised interventional feasibility study. The 5UTT was self-administered daily and the median U-turn speed, measured during a 14-day session, was compared against existing validated in-clinic measures of MS-related disability.

RESULTS

U-turn speed, measured during a 14-day session from the 5UTT, demonstrated good-to-excellent test-retest reliability in PwMS alone and combined with HCs (intraclass correlation coefficient [ICC] = 0.87 [95 % CI: 0.80-0.92]) and moderate-to-excellent reliability in HCs alone (ICC = 0.88 [95 % CI: 0.69-0.96]). U-turn speed was significantly correlated with in-clinic measures of walking speed, physical fatigue, ambulation impairment, overall MS-related disability and patients' self-perception of quality of life, at baseline, Week 12 and Week 24. The minimal detectable change of the U-turn speed from the 5UTT was low (19.42 %) in PwMS and indicates a good precision of this measurement tool when compared with conventional in-clinic measures of walking performance.

SIGNIFICANCE

The frequent self-assessment of turn speed, as an outcome measure from a smartphone-based U-turn test, may represent an ecologically valid digital solution to remotely and reliably monitor gait and balance impairment in a home environment during MS clinical trials and practice.

Technology to Improve Autonomy and Inform Housing Decisions for Older Adults With Memory Problems Who Live at Home in Canada, Sweden, and the Netherlands: Protocol for a Multipronged Mixed Methods Study

BACKGROUND

Understanding the mobility patterns and experiences of older adults with memory problems living at home has the potential to improve autonomy and inform shared decision making (SDM) about their housing options.

OBJECTIVE

We aim to (1) assess the mobility patterns and experiences of older adults with memory problems, (2) co-design an electronic decision support intervention (e-DSI) that integrates users' mobility patterns and experiences, (3) explore their intention to use an e-DSI to support autonomy at home, and (4) inform future SDM processes about housing options.

METHODS

Informed by the Good Reporting of A Mixed Methods Study (GRAMMS) reporting guidelines, we will conduct a 3-year, multipronged mixed methods study in Canada, Sweden, and the Netherlands. For Phase 1, we will recruit a convenience sample of 20 older adults living at home with memory problems from clinical and community settings in each country, for a total of 60 participants. We will ask participants to record their mobility patterns outside their home for 14 days using a GPS tracker and a travel diary; in addition, we will conduct a walking interview and a final debrief interview after 14 days. For Phase 2, referring to results from the first phase, we will conduct one user-centered co-design process per country with older adults with memory issues, caregivers, health care professionals, and information technology representatives informed by the Double Diamond method. We will ask participants how personalized information about mobility patterns and experiences could be added to an existing e-DSI and how this information could inform SDM about housing options. For Phase 3, using online web-based surveys, we will invite 210 older adults with memory problems and/or their caregivers, split equally across the three countries, to use the e-DSI and provide feedback on its strengths and limitations. Finally, in Phase 4, we will triangulate and compare data from all phases and countries to inform a stakeholder meeting where an action plan will be developed.

RESULTS

The study opened for recruitment in the Netherlands in November 2018 and in Canada and Sweden in December 2019. Data collection will be completed by April 2021.

CONCLUSIONS

This project will explore how e-DSIs can integrate the mobility patterns and mobility experiences of older adults with memory problems in three countries, improve older adults' autonomy, and, ultimately, inform SDM about housing options.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04267484; https://clinicaltrials.gov/ct2/show/NCT04267484.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/19244.

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.

Prevalence and patterns of subclinical motor and cognitive impairments in non-disabled individuals with early multiple sclerosis: a multicenter cross-sectional study

BACKGROUND

Motor and cognitive disorders appear early in the course of multiple sclerosis (MS) and develop gradually over time.

OBJECTIVE

To study the frequency and pattern of subtle functional disorders in people with MS (PwMS) with no overt signs of disability in an early phase of the disease and their association with walking impairments in daily activities.

METHODS

In this cross-sectional study, we recruited PwMS with an Expanded Disability Status Scale (EDSS) score ≤ 2.5 and disease duration ≤ 5 years. Participants were assessed with functional scales rating walking endurance (6-Min Walk Test), perceived walking ability (Twelve-item Multiple Sclerosis Walking Scale), balance (Fullerton Advanced Balance scale_short), manual dexterity (Nine Hole Peg Test), fatigue (Fatigue Severity Scale), and cognitive impairments (Brief International Cognitive Assessment).

RESULTS

About 90% of the 82 PwMS (mean [SD] EDSS score 1.5 [0.7] and disease duration 2.2 [1.7] years) showed endurance values below the expected score; almost 30% showed impairment, and for 57%, perceived walking ability score was abnormal. Balance was impaired in 48% of participants, as was manual dexterity (29%) and fatigue (24%), but only a few showed cognitive impairments. Only 11% of PwMS had no abnormal score on the scales used in the assessment. As compared with EDSS score 0 to 1.5, with EDSS score 2 to 2.5, performance was worse for endurance (difference ±61.0 m, p=0.016), perceived walking ability (-11 points, p=0.002), balance (+1.9 points, p=0.005), manual dexterity (-2.8 sec, p=0.004), and fatigue (-1.3 points, p=0.013). Factors that predicted perceived walking ability were balance (B = -1.37, p<0.001) and fatigue (B = 5.11, p<0.001) rather than endurance (B = -0.01, p=048).

CONCLUSION

Even PwMS with no clinical disability and classified as having "no problem walking" present walking and other functional deficits when assessed with specific functional tests. The addition of specific tools could better identify subtle motor and cognitive deficits. Finally, the assessment of balance disorders and fatigue is important to understand individuals' perceived walking impairments in daily activities.

Usefulness of Mobile Devices in the Diagnosis and Rehabilitation of Patients with Dizziness and Balance Disorders: A State of the Art Review

Objective

The gold standard for objective body posture examination is posturography. Body movements are detected through the use of force platforms that assess static and dynamic balance (conventional posturography). In recent years, new technologies like wearable sensors (mobile posturography) have been applied during complex dynamic activities to diagnose and rehabilitate balance disorders. They are used in healthy people, especially in the aging population, for detecting falls in the older adults, in the rehabilitation of different neurological, osteoarticular, and muscular system diseases, and in vestibular disorders. Mobile devices are portable, lightweight, and less expensive than conventional posturography. The vibrotactile system can consist of an accelerometer (linear acceleration measurement), gyroscopes (angular acceleration measurement), and magnetometers (heading measurement, relative to the Earth’s magnetic field). The sensors may be mounted to the trunk (most often in the lumbar region of the spine, and the pelvis), wrists, arms, sternum, feet, or shins. Some static and dynamic clinical tests have been performed with the use of wearable sensors. Smartphones are widely used as a mobile computing platform and to evaluate the results or monitor the patient during the movement and rehabilitation. There are various mobile applications for smartphone-based balance systems. Future research should focus on validating the sensitivity and reliability of mobile device measurements compared to conventional posturography.

Conclusion

Smartphone based mobile devices are limited to one sensor lumbar level posturography and offer basic clinical evaluation. Single or multi sensor mobile posturography is available from different manufacturers and offers single to multi-level measurements, providing more data and in some instances even performing sophisticated clinical balance tests.

EFFECTS OF WHOLE-BODY VIBRATION ON MUSCLE STRENGTH, BALANCE AND FUNCTIONAL MOBILITY IN PATIENTS WITH MULTIPLE SCLEROSIS: A SYSTEMATIC REVIEW AND META-ANALYSIS

Multiple sclerosis (MS) is a type of degenerative syndrome that causes impaired physical function, decreased walking, imbalance, spasticity, sensory impairment, muscle weakness, fatigue, and demyelination of the central nervous system. The purpose of this review was to critically examine available studies on the efficacy of whole-body vibration (WBV) in patients with MS during rehabilitation training to increase strength, balance, and functional mobility. An organized literature search was performed on databases from various sources, including PubMed, MEDLINE, CINAHL, and EMBASE, to identify relevant randomized clinical trials (RCTs). Eight studies were finally selected based on exclusion and inclusion criteria. Attempts were made to identify factors affecting the improvement in muscle strength, balance, and functional mobility in MS patients as a result of WBV. A meta-analysis was performed if two or more studies measured the same outcome of interest. The meta-analysis found that the WBV intervention showed significant improvement over control groups in Body Balance Score (BBS) (MD = [Formula: see text]2.86, 95%CI = [Formula: see text]5.29 [Formula: see text] 0.43; [Formula: see text], [Formula: see text], heterogeneity ([Formula: see text]%). In addition, walking endurance (6MWT) favored control groups over WBV intervention (MD [Formula: see text], 95%CI [Formula: see text][Formula: see text] 99.41; [Formula: see text] = 2.97, [Formula: see text]). Timed-Up-and-Go Test (TUG) and Expanded Disability Status Scale (EDSS) ([Formula: see text]) had no significant effect on WBV. Restoration of balance and functional mobility appeared to respond better to WBV with additional exercise protocols compared to WBV alone. Although there is evidence of an overall effect of WBV on strength and some measures of balance and mobility, its impact remains inconclusive. Therefore, more robust RCTs examining exposure to WBV on balance and functional mobility in patients with MS are warranted.

Laboratory versus daily life gait characteristics in patients with multiple sclerosis, Parkinson's disease, and matched controls

BACKGROUND AND PURPOSE

Recent findings suggest that a gait assessment at a discrete moment in a clinic or laboratory setting may not reflect functional, everyday mobility. As a step towards better understanding gait during daily life in neurological populations, we compared gait measures that best discriminated people with multiple sclerosis (MS) and people with Parkinson's Disease (PD) from their respective, age-matched, healthy control subjects (MS-Ctl, PD-Ctl) in laboratory tests versus a week of daily life monitoring.

METHODS

We recruited 15 people with MS (age mean ± SD: 49 ± 10 years), 16 MS-Ctl (45 ± 11 years), 16 people with idiopathic PD (71 ± 5 years), and 15 PD-Ctl (69 ± 7 years). Subjects wore 3 inertial sensors (one each foot and lower back) in the laboratory followed by 7 days during daily life. Mann-Whitney U test and area under the curve (AUC) compared differences between PD and PD-Ctl, and between MS and MS-Ctl in the laboratory and in daily life.

RESULTS

Participants wore sensors for 60-68 h in daily life. Measures that best discriminated gait characteristics in people with MS and PD from their respective control groups were different between the laboratory gait test and a week of daily life. Specifically, the toe-off angle best discriminated MS versus MS-Ctl in the laboratory (AUC [95% CI] = 0.80 [0.63-0.96]) whereas gait speed in daily life (AUC = 0.84 [0.69-1.00]). In contrast, the lumbar coronal range of motion best discriminated PD versus PD-Ctl in the laboratory (AUC = 0.78 [0.59-0.96]) whereas foot-strike angle in daily life (AUC = 0.84 [0.70-0.98]). AUCs were larger in daily life compared to the laboratory.

CONCLUSIONS

Larger AUC for daily life gait measures compared to the laboratory gait measures suggest that daily life monitoring may be more sensitive to impairments from neurological disease, but each neurological disease may require different gait outcome measures.

Inertial Sensor Algorithms to Characterize Turning in Neurological Patients With Turn Hesitations

BACKGROUND

One difficulty in turning algorithm design for inertial sensors is detecting two discrete turns in the same direction, close in time. A second difficulty is under-estimation of turn angle due to short-duration hesitations by people with neurological disorders. We aimed to validate and determine the generalizability of a: I. Discrete Turn Algorithm for variable and sequential turns close in time and II: Merged Turn Algorithm for a single turn angle in the presence of hesitations.

METHODS

We validated the Discrete Turn Algorithm with motion capture in healthy controls (HC, n = 10) performing a spectrum of turn angles. Subsequently, the generalizability of the Discrete Turn Algorithm and associated, Merged Turn Algorithm were tested in people with Parkinson's disease (PD, n = 124), spinocerebellar ataxia (SCA, n = 51), and HC (n = 125).

RESULTS

The Discrete Turn Algorithm shows improved agreement with optical motion capture and with known turn angles, compared to our previous algorithm by El-Gohary et al. The Merged Turn algorithm that merges consecutive turns in the same direction with short hesitations resulted in turn angle estimates closer to a fixed 180-degree turn angle in the PD, SCA, and HC subjects compared to our previous turn algorithm. Additional metrics were proposed to capture turn hesitations in PD and SCA.

CONCLUSION

The Discrete Turn Algorithm may be particularly useful to characterize turns when the turn angle is unknown, i.e., during free-living conditions. The Merged Turn algorithm is recommended for clinical tasks in which the single-turn angle is known, especially for patients who hesitate while turning.

The Dresden Protocol for Multidimensional Walking Assessment (DMWA) in Clinical Practice

Walking impairments represent one of the most debilitating symptom areas for people with multiple sclerosis (MS). It is important to detect even slightest walking impairments in order to start and optimize necessary interventions in time to counteract further progression of the disability. For this reason, a regular monitoring through gait analysis is highly necessary. At advanced stages of MS with significant walking impairment, this assessment is also necessary to optimize symptomatic treatment, choose the most suitable walking aid and plan individualized rehabilitation. In clinical practice, walking impairment is only assessed at higher levels of the disease using e.g., the Expanded Disability Status Scale (EDSS). In contrast to the EDSS, standardized functional tests such as walking speed, walking endurance and balance as well as walking quality and gait-related patient-reported outcomes allow a more holistic and sensitive assessment of walking impairment. In recent years, the MS Center Dresden has established a standardized monitoring procedure for the routine multidimensional assessment of gait and balance disorders. In the following protocol, we present the techniques and procedures for the analysis of gait and balance of people with MS at the MS Center Dresden. Patients are assessed with a multidimensional gait analysis at least once a year. This enables long-term monitoring of walking impairment, which allows early active intervention regarding further progression of disease and improves the current standard clinical practice.

Optimization of IMU Sensor Placement for the Measurement of Lower Limb Joint Kinematics

There is an increased interest in using wearable inertial measurement units (IMUs) in clinical contexts for the diagnosis and rehabilitation of gait pathologies. Despite this interest, there is a lack of research regarding optimal sensor placement when measuring joint kinematics and few studies which examine functionally relevant motions other than straight level walking. The goal of this clinical measurement research study was to investigate how the location of IMU sensors on the lower body impact the accuracy of IMU-based hip, knee, and ankle angular kinematics. IMUs were placed on 11 different locations on the body to measure lower limb joint angles in seven participants performing the timed-up-and-go (TUG) test. Angles were determined using different combinations of IMUs and the TUG was segmented into different functional movements. Mean bias and root mean square error values were computed using generalized estimating equations comparing IMU-derived angles to a reference optical motion capture system. Bias and RMSE values vary with the sensor position. This effect is partially dependent on the functional movement analyzed and the joint angle measured. However, certain combinations of sensors produce lower bias and RMSE more often than others. The data presented here can inform clinicians and researchers of placement of IMUs on the body that will produce lower error when measuring joint kinematics for multiple functionally relevant motions. Optimization of IMU-based kinematic measurements is important because of increased interest in the use of IMUs to inform diagnose and rehabilitation in clinical settings and at home.

Gait Characteristics Harvested During a Smartphone-Based Self-Administered 2-Minute Walk Test in People with Multiple Sclerosis: Test-Retest Reliability and Minimum Detectable Change

The measurement of gait characteristics during a self-administered 2-minute walk test (2MWT), in persons with multiple sclerosis (PwMS), using a single body-worn device, has the potential to provide high-density longitudinal information on disease progression, beyond what is currently measured in the clinician-administered 2MWT. The purpose of this study is to determine the test-retest reliability, standard error of measurement (SEM) and minimum detectable change (MDC) of features calculated on gait characteristics, harvested during a self-administered 2MWT in a home environment, in 51 PwMS and 11 healthy control (HC) subjects over 24 weeks, using a single waist-worn inertial sensor-based smartphone. Excellent, or good to excellent test-retest reliability were observed in 58 of the 92 temporal, spatial and spatiotemporal gait features in PwMS. However, these were less reliable for HCs. Low SEM% and MDC% values were observed for most of the distribution measures for all gait characteristics for PwMS and HCs. This study demonstrates the inter-session test-retest reliability and provides an indication of clinically important change estimates, for interpreting the outcomes of gait characteristics measured using a body-worn smartphone, during a self-administered 2MWT. This system thus provides a reliable measure of gait characteristics in PwMS, supporting its application for the longitudinal assessment of gait deficits in this population.

Balance Deficits due to Cerebellar Ataxia: A Machine Learning and Cloud-Based Approach

Cerebellar ataxia (CA) refers to the disordered movement that occurs when the cerebellum is injured or affected by disease. It manifests as uncoordinated movement of the limbs, speech, and balance. This study is aimed at the formation of a simple, objective framework for the quantitative assessment of CA based on motion data. We adopted the Recurrence Quantification Analysis concept in identifying features of significance for the diagnosis. Eighty-six subjects were observed undertaking three standard neurological tests (Romberg's, Heel-shin and Truncal ataxia) to capture 213 time series inertial measurements each. The feature selection was based on engaging six different common techniques to distinguish feature subset for diagnosis and severity assessment separately. The Gaussian Naive Bayes classifier performed best in diagnosing CA with an average double cross-validation accuracy, sensitivity, and specificity of 88.24%, 85.89%, and 92.31%, respectively. Regarding severity assessment, the voting regression model exhibited a significant correlation (0.72 Pearson) with the clinical scores in the case of the Romberg's test. The Heel-shin and Truncal tests were considered for diagnosis and assessment of severity concerning subjects who were unable to stand. The underlying approach proposes a reliable, comprehensive framework for the assessment of postural stability due to cerebellar dysfunction using a single inertial measurement unit.

Short Bouts of Gait Data and Body-Worn Inertial Sensors Can Provide Reliable Measures of Spatiotemporal Gait Parameters from Bilateral Gait Data for Persons with Multiple Sclerosis

Wearable devices equipped with inertial sensors enable objective gait assessment for persons with multiple sclerosis (MS), with potential use in ambulatory care or home and community-based assessments. However, gait data collected in non-controlled settings are often fragmented and may not provide enough information for reliable measures. This paper evaluates a novel approach to (1) determine the effects of the length of the walking task on the reliability of calculated measures and (2) identify digital biomarkers for gait assessments from fragmented data. Thirty-seven participants (37) diagnosed with relapsing-remitting MS (EDSS range 0 to 4.5) executed two trials, walking 20 m each, with inertial sensors attached to their right and left shanks. Gait events were identified from the medio-lateral angular velocity, and short bouts of gait data were extracted from each trial, with lengths varying from 3 to 9 gait cycles. Intraclass correlation coefficients (ICCs) evaluate the degree of agreement between the two trials of each participant, according to the number of gait cycles included in the analysis. Results show that short bouts of gait data, including at least six gait cycles of bilateral data, can provide reliable gait measurements for persons with MS, opening new perspectives for gait assessment using fragmented data (e.g., wearable devices, community assessments). Stride time variability and asymmetry, as well as stride velocity variability and asymmetry, should be further explored as digital biomarkers to support the monitoring of symptoms of persons with neurological diseases.

Body-Worn Sensors Are a Valid Alternative to Forceplates for Measuring Balance in Children

Aims

Clinical evaluation of balance has relied on forceplate systems as the gold standard for postural sway measures. Recently, systems based on wireless inertial sensors have been explored, mostly in the adult population, as an alternative given their practicality and lower cost. Our goal was to validate body-worn sensors against forceplate balance measures in typically developing children during tests of quiet stance.

Methods

18 participants (8 males) 7 to 17 years old performed a quiet stance test standing on a forceplate while wearing 3 inertial sensors. Three 30-second trials were performed under 4 conditions: firm surface with eyes open and closed, and foam surface with eyes open and closed. Sway area, path length, and sway velocity were calculated.

Results

We found 20 significant and 8 non-significant correlations. Variables found to be significant were represented across all conditions, except for the foam eyes closed condition.

Conclusions

These results support the validity of wearable sensors in measuring postural sway in children. Inertial sensors may represent a viable alternative to the gold standard forceplate to test static balance in children.

Clinical assessment, management, and rehabilitation of walking impairment in MS: an expert review

INTRODUCTION

One of the most common and life-altering consequences of Multiple Sclerosis (MS) is walking impairment. The distance, speed, and Gait pattern functions are components of the International Classification of Functioning, Disability, and Health (ICF) and are also predictors of dependency in terms of daily living activities in patients with MS (pwMS).

AREAS COVERED

This article provides an overview of walking impairment in pwMS, with focus on the assessment of gait and the rehabilitation approaches.

EXPERT OPINION

The authors recommend that pwMS undergo gait assessment integrating the ICF perspective using validated clinical outcome measures that cover spatiotemporal gait parameters. Moreover, assessment of walking speed with short walking capacity tests such as the timed 25-foot walk (T25FW) or the 10-m walk test (10 MWT) and tests for walking distance with middle distance tests such as the 2-min walk test (2MWT) and the 6-min walk test (6MWT). This review further highlights strategies that may restore walking function including pharmacological symptomatic treatment and non-pharmacological rehabilitation approaches such as exercise and task-specific training providing an appraisal of mobility targeted therapies to be considered when planning multidisciplinary comprehensive-care of pwMS. Finally, new and novel strategies such as motor imagery and rhythmic auditory stimulation have been developed to improve walking speed and distance in pwMS.

Fifteen Years of Wireless Sensors for Balance Assessment in Neurological Disorders

Balance impairment is a major mechanism behind falling along with environmental hazards. Under physiological conditions, ageing leads to a progressive decline in balance control per se. Moreover, various neurological disorders further increase the risk of falls by deteriorating specific nervous system functions contributing to balance. Over the last 15 years, significant advancements in technology have provided wearable solutions for balance evaluation and the management of postural instability in patients with neurological disorders. This narrative review aims to address the topic of balance and wireless sensors in several neurological disorders, including Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, stroke, and other neurodegenerative and acute clinical syndromes. The review discusses the physiological and pathophysiological bases of balance in neurological disorders as well as the traditional and innovative instruments currently available for balance assessment. The technical and clinical perspectives of wearable technologies, as well as current challenges in the field of teleneurology, are also examined.

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.

Structural Neural Correlates of Impaired Postural Control in People with Secondary Progressive Multiple Sclerosis

BACKGROUND

Secondary progressive multiple sclerosis (SPMS) is characterized by worsening of postural control and brain atrophy. However, little is known about postural deficits and their neuroanatomical correlates in this population. We aimed to determine the neuroanatomical correlates of postural deficits in people with SPMS and whether posture control deteriorates concomitantly with the brain and spinal cord atrophy in 2 years in SPMS.

METHODS

This study is a post hoc analysis of data from 27 people with SPMS (mean ± SE age, 58.6 ± 1.1 years). Participants had magnetic resonance imaging (MRI) of the brain and cervical spinal cord followed by sway testing using inertial sensors during standing with eyes open (EO) and eyes closed without (EC) and with (ECC) a cognitive task. Partial correlations investigated relationships between postural control and MRI measures at baseline and 2 years.

RESULTS

At baseline, sway measures were inversely related to cortical thickness and cord cross-sectional area (CSA) during the EO task but only to cord CSA with EC (P < .05). After 2 years, the percentage change in sway amplitude and dispersion during EO tasks significantly related to the percentage decline in cord CSA (P < .01).

CONCLUSIONS

Cortical and spinal cord inputs are essential for regulation of postural control during standing with EO in SPMS. Without visual input, people with SPMS preferentially rely on somatosensory inputs from the spinal cord for maintaining postural control. Postural deficits related to cord atrophy over 2 years, suggesting that postural control may be a surrogate marker of disease progression in people with SPMS.

Demonstration of the Effect of Centre of Mass Height on Postural Sway Using Accelerometry for Balance Analysis

The effect of center of mass (COM) height on stand-still postural sway analysis was studied. For this purpose, a measurement apparatus was set up that included an accelerometry device attached to a rod: three plumb lines, positioned at 50, 75 and 100 cm to an end of the rod, each supported a plumb bob. Using a vice mechanism, the rod was inclined from vertical (0 degree inclination) in steps of 5 degrees to 90 degrees. For each inclination, the corresponding inclination angle was manually measured by a protractor and the positions of the three plumb bobs on the ground surface were also manually measured using a tape measure. Algebraic operations were used to calculate the inclination angle and the associated displacements of the plumb bobs on the ground surface from the accelerometry data. For each inclination angle, the manual and accelerometry calculated ground displacement were close. The height of COM, where the measurement was taken, affected the projected displacement on the ground surface. The COM height had a nonlinear double-effect relationship with sway as it can affect both the angle and projected sway. Normalization of the COM height was used to reduce this effect for comparison purposes.

The immediate effect of stroboscopic visual training on information-processing time in people with multiple sclerosis: an exploratory study

Stroboscopic visual training (SVT) is a form of training aimed at improving visual and perceptual performance by having individuals perform activities under conditions of intermittent vision. The efficacy of SVT has never been examined in people with multiple sclerosis (PwMS), therefore, our aim was to examine the immediate effect of SVT on cognitive function, gait and static balance performance in PwMS. This assessor-blinded, randomized crossover study included 26 PwMS, 16 females, mean age 47.9 and median EDSS score 4.5. Participants attended two sessions: SVT and control training. Exercises for both the SVT and control sessions were based on ball-catching tasks. Training sessions were identical in length (40-50 min) and type of exercise drills. The difference between the two practice regimes was that the SVT session was performed wearing stroboscopic glasses and the control training was performed with similar glasses without lenses. Cognition was evaluated by a computerized software (Mindstreams^®, NeuroTrax Corp., NY). Gait and balance were evaluated via wearable accelerometers (APDM, Oregon, USA). Outcome measures were collected twice during a single session, prior to training and immediately afterward. Information processing speed (p = 0.003) increased at the post-evaluation compared with baseline, solely in the SVT session. No differences between pre-post evaluations were observed for other cognitive scores following the SVT session. No differences between pre-post measurements were noted for gait and balance following the SVT session. The present study's results justify performing future RCT studies to examine the effects of a longer SVT program on cognition in PwMS.

The Warrior Athlete Part 2-Return to Duty in the US Military: Advancing ACL Rehabilitation in the Tactical Athlete

Rehabilitation following an anterior cruciate ligament reconstruction is a crucial component of the healing and recovery process and full return to duty/play in the tactical modern-day warfighter. The burden of anterior cruciate ligament injuries and subsequent loss of readiness in these military warfighters highlights one of the most significant gaps in musculoskeletal injury care today. Emphasis must be placed on early weight-bearing and range of motion (ROM), namely in this athlete population, to best facilitate a timely care and recovery process. Preoperative rehabilitation should commence immediately following the diagnosis of an anterior cruciate ligament tear, because one of the best predictors of postoperative ROM is preoperative ROM. Recent advances in rehabilitation technology such as Alter-G treadmills, inertial measurement units, and blood flow restriction therapy systems, have demonstrated success in the early rehabilitation of tactical athletes. Alter-G treadmills allow for early weight-bearing with reduced impact and progression in ROM following operative management, while inertial measurement units have been applied to tailoring rehabilitation protocols specifically to an athlete's unique functional deficits. When used in conjunction with a fined tune rehabilitation protocol, implemented by a well versed clinical team, these treatment techniques can greatly expedite the return to duty process and limit long-term complications.

Using Body-Worn Sensors to Detect Changes in Balance and Mobility After Acute Aerobic Exercise in Adults with Multiple Sclerosis

Background

Current mobility and functional assessments do not capture the subtle changes in balance and gait that may predispose people with multiple sclerosis (MS) to falling. The purpose of this study was to use clinical and instrumented measures to examine the effects of an acute bout of aerobic exercise on balance and gait in individuals with MS.

Methods

Ten adults with MS performed 15 minutes of moderate-intensity recumbent cycling or 15 minutes of rest. Exercise and rest visit order was randomized and separated by 1 week. Balance and mobility were assessed before, immediately after, and 2 hours after each test condition.

Results

There were no significant differences across measurement periods for Timed 25-Foot Walk test times or Brief Balance Evaluation Systems Test scores. Significant improvements in mean sway radius and sway velocity when standing on foam and in percentage of stance stride time variability were found immediately after exercise compared with immediately after rest.

Conclusions

This study lends further evidence that individuals with MS can safely engage in single bouts of aerobic exercise without detrimental short-term effects on function and may actually receive some short-term benefit regarding standing postural sway and gait variability. Future research should examine the dose-dependent relationship of varying types, intensities, or timing of exercise necessary to elicit short-term functional benefit and long-term health outcomes.

Biosensors to monitor MS activity

Advances in wearable and wireless biosensing technology pave the way for a brave new world of novel multiple sclerosis (MS) outcome measures. Our current tools for examining patients date back to the 19th century and while invaluable to the neurologist invite accompaniment from these new technologies and artificial intelligence (AI) analytical methods. While the most common biosensor tool used in MS publications to date is the accelerometer, the landscape is changing quickly with multi-sensor applications, electrodermal sensors, and wireless radiofrequency waves. Some caution is warranted to ensure novel outcomes have clear clinical relevance and stand-up to the rigors of reliability, reproducibility, and precision, but the ultimate implementation of biosensing in the MS clinical setting is inevitable.

Wearable-based Temporal Parameters of Gait in Circuitous Routes under Dual-Task Conditions

12 young adults were requested to walk along a circuitous path including turns, slaloms, stair ascending and descending, while wearing an inertial sensor placed on the back at the lumbar level. The path was completed under two conditions: with no additive cognitive task, and while performing a cognitive task and texting on a smartphone. Different temporal global parameters of gait were extracted from the inertial sensor data, to check for differences driven by the presence of the cognitive task. Regularity, durations, and temporal characteristics of gait resulted significantly affected from the presence of the additional task, and this effect was only in part due to a modification coming from the decrease in walking speed.

Does Instructor Experience Impact Balance and Health-Related Quality of Life in Healthy Older Adult Participants following a Tai Chi for Arthritis Program?

Tai chi improves balance in older adults; however, the level of instructor expertise on balance outcomes is not known. Older adults (mean age 72.6 ± 4.2 yrs.) were taught for 6 months by experienced (n = 15) or novice (n = 11) instructors. Both groups had large standardized response means (SRM) for the Four-Square-Step-Test. Only the experienced group had moderate to large SRMs (range 0.439-0.741) in all sway measures under challenge (standing with eyes closed on foam). Participants taught by experienced instructors had greater balance gains; the experience of instructors should be considered in future studies and community referrals.

Use of Wearable Sensor Technology in Gait, Balance, and Range of Motion Analysis

More than 8.6 million people suffer from neurological disorders that affect their gait and balance. Physical therapists provide interventions to improve patient’s functional outcomes, yet balance and gait are often evaluated in a subjective and observational manner. The use of quantitative methods allows for assessment and tracking of patient progress during and after rehabilitation or for early diagnosis of movement disorders. This paper surveys the state-of-the-art in wearable sensor technology in gait, balance, and range of motion research. It serves as a point of reference for future research, describing current solutions and challenges in the field. A two-level taxonomy of rehabilitation assessment is introduced with evaluation metrics and common algorithms utilized in wearable sensor systems.

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.

[Enhancing monitoring of disease progression-remote sensoring in multiple sclerosis]

BACKGROUND

As a result of innovations in the digitalization of healthcare new technologies, such as remote sensoring are gaining in importance for the collection of real-life data in addition to the regular medical examination. This enables a closer view into the daily lives of patients with multiple sclerosis and a more detailed monitoring of disease progression.

OBJECTIVE

This article gives a summary of sensor-based measurement technologies in the field of multiple sclerosis RESULTS: A wide variety of sensor-based measurement technologies are already available, which largely focus on gait analysis and mobility. Furthermore, there are many innovative approaches for a sensor-based collation of the multifocal symptoms of multiple sclerosis, for example technologies focus on the area of stress surveillance, the autonomic nervous system, GPS tracking and sleep monitoring.

DISCUSSION

Despite the existence of many already available technologies, the aim is now to find a practical way to integrate them into the daily routine of patient monitoring, which includes standardized data collection, evaluation and interpretation. Only at this point a perspective benefit for treating physicians and patients can be achieved.

Reference value for the TUGT in healthy older people: A systematic review and meta-analysis

The timed up and go test (TUGT) was recently proposed as a strong predictor of adverse outcomes. Few reviews have been conducted to identify a standard for the TUGT in healthy older people, and the aims of this study were to explore the source of heterogeneity and evaluate the range of reference values for the TUGT in healthy people over 60 years old stratified by age and sex. The VIP, EMBASE, Web of Science and PubMed databases were searched from January 1, 2000, to December 31, 2018. A subgroup analysis and meta-regression were used to assess heterogeneity. Thirty-four eligible studies were included. The mean TUGT results for the total population, males and females in the sample were 9.21 s [95% CI (9.11, 9.31)], 9.33 s [95% CI (7.82, 11.08)] and 8.87 s [95% CI (8.40, 9.38)], respectively. The mean TUGT results for older people in their 60 s, 70 s, and 80 s were 7.91 s [95% CI (6.62, 9.20)], 8.67 s [95% CI (7.23, 10.12)] and 11.68 s [95% CI (8.11, 15.26)], respectively. The meta-regression analysis results showed that the heterogeneity was related to age (P < 0.01). Age affects the results of the TUGT, and it is necessary to take age into consideration when conducting stratified physical evaluations for the evaluation of older people individuals' physical fitness.

Changes in standing stability with balance-based torso-weighting with cerebellar ataxia: A pilot study

Objectives

People with cerebellar ataxia have few options to improve the standing stability they need for function. Strategic placement of light weights on the torso using the balance‐based torso‐weighting (BBTW) method has improved stability and reduced falls in people with multiple sclerosis, but has not been tested in cerebellar ataxia. We examined whether torso‐weighting increased standing stability and/or functional movement in people with cerebellar ataxia.

Methods

Ten people with cerebellar ataxia and 10 matched controls participated in this single‐session quasi‐experimental pilot study. People with ataxia performed the Scale for the Assessment and Rating of Ataxia (SARA) prior to clinical testing. All participants donned inertial sensors that recorded postural sway; stopwatches recorded duration for standing and mobility tasks. All participants stood for up to 30 s on firm and foam surfaces with eyes open then eyes closed, and performed the Timed Up and Go (TUG) test. Light weights (0.57–1.25 kg) were strategically applied to a vest‐like garment. Paired t tests compared within‐group differences with and without BBTW weights. Independent t tests assessed differences from controls. All t tests were one‐tailed with alpha set at .05.

Results

Duration of standing for people with ataxia was significantly longer with weighting (p = .004); all controls stood for the maximum time of 120 s with and without weights. More severe ataxia according to SARA was moderately correlated with greater improvement in standing duration with BBTW (Pearson r = .54). Tasks with more sensory challenges (eyes closed, standing on firm surface) showed less body sway with weighting. Duration for the TUG was unchanged by torso‐weighting in people with ataxia.

Conclusion

Strategic weighting improved standing stability but not movement speed in people with ataxia. BBTW has potential for improving stability and response to challenging sensory conditions in this population. Future studies should further examine gait stability measures along with movement speed.

Fall Risk Prediction in Multiple Sclerosis Using Postural Sway Measures: A Machine Learning Approach

Numerous postural sway metrics have been shown to be sensitive to balance impairment and fall risk in individuals with MS. Yet, there are no guidelines concerning the most appropriate postural sway metrics to monitor impairment. This investigation implemented a machine learning approach to assess the accuracy and feature importance of various postural sway metrics to differentiate individuals with MS from healthy controls as a function of physiological fall risk. 153 participants (50 controls and 103 individuals with MS) underwent a static posturography assessment and a physiological fall risk assessment. Participants were further classified into four subgroups based on fall risk: controls, low-risk MS (n = 34), moderate-risk MS (n = 27), high-risk MS (n = 42). Twenty common sway metrics were derived following standard procedures and subsequently used to train a machine learning algorithm (random forest - RF, with 10-fold cross validation) to predict individuals' fall risk grouping. The sway-metric based RF classifier had high accuracy in discriminating controls from MS individuals (>86%). Sway sample entropy was identified as the strongest feature for classification of low-risk MS individuals from healthy controls. Whereas for all other comparisons, mediolateral sway amplitude was identified as the strongest predictor for fall risk groupings.

Quantitative Synthesis of Timed 25-Foot Walk Performance in Multiple Sclerosis

OBJECTIVE

To provide a meta-analysis of articles that have included the timed 25-foot walk (T25FW) in persons with multiple sclerosis (MS), quantify differences in T25FW scores between those with MS and controls without MS, and quantify differences between categories of disability status and clinical disease courses within MS.

DATA SOURCES

The literature search was conducted using 4 databases (Google Scholar, PubMed, Cumulative Index to Nursing and Allied Health, EBSCO Host). We searched reference lists of published articles to identify additional articles.

STUDY SELECTION

A systematic literature search identified articles reporting average T25FW performance in seconds between those with MS and controls without MS, between those with MS who had mild and moderate and/or severe disability status, and between relapsing-remitting and progressive clinical courses of MS.

DATA EXTRACTION

Information was extracted and categorized based on reported data: comparisons of controls without MS and MS, comparisons of mild and moderate and/or severe MS based on study-defined Expanded Disability Status Scale groups, and comparisons of relapsing-remitting and progressive MS clinical courses.

DATA SYNTHESIS

We performed a random effects meta-analysis to quantify differences between groups as estimated by effect sizes (ESs). We expressed the differences in Cohen d as well as the original units of the T25FW (ie, seconds).

CONCLUSIONS

There was a large difference in T25FW performance in MS compared with controls without MS (ES=-0.93, mean difference=2.4s, P<.01). Persons with moderate and/or severe disability walked substantially slower compared with mild disability (ES=-1.02, mean difference=5.4s, P<.01), and persons with progressive courses of MS walked substantially slower than relapsing-remitting MS (ES=-1.4, mean difference=13.4s, P<.01).

Comparison of a Low-Cost Miniature Inertial Sensor Module and a Fiber-Optic Gyroscope for Clinical Balance and Gait Assessments

Objective

To investigate whether a microelectromechanical system (MEMS) inertial sensor module is as accurate as fiber-optic gyroscopes when classifying subjects as normal for clinical stance and gait balance tasks.

Methods

Data of ten healthy subjects were recorded simultaneously with a fiber-optic gyroscope (FOG) system of SwayStar™ and a MEMS sensor system incorporated in the Valedo® system. Data from a sequence of clinical balance tasks with different angle and angular velocity ranges were assessed. Paired t-tests were performed to determine significant differences between measurement systems. Cohen's kappa test was used to determine the classification of normal balance control between the two sensor systems when comparing the results to a reference database recorded with the FOG system. Potential cross-talk errors in roll and pitch angles when neglecting yaw axis rotations were evaluated by comparing 2D FOG and 3D MEMS recordings.

Results

Statistically significant (α=0.05) differences were found in some balance tasks, for example, “walking eight tandem steps” and various angular measures (p < 0.03). However, these differences were within a few percent (<2.7%) of the reference values. Tasks with high dynamic velocity ranges showed significant differences (p=0.002) between 2D FOG and 3D MEMS roll angles but no difference between 2D FOG and 2D MEMS roll angles. An almost perfect agreement could be obtained for both 2D FOG and 2D MEMS (κ=0.97) and 2D FOG and 3D MEMS measures (κ=0.87) when comparing measurements of all subjects and tasks.

Conclusion

MEMS motion sensors can be used for assessing balance during clinical stance and gait tasks. MEMS provides measurements comparable to values obtained with a highly accurate FOG. When assessing pitch and roll trunk sway measures without accounting for the effect of yaw, it is recommended to use angle and angular velocity measures for stance, and only angular velocity measures for gait because roll and pitch velocity measurements are not influenced by yaw rotations, and angle errors are low for stance.

Wearable Inertial Sensors to Assess Standing Balance: A Systematic Review

Wearable sensors are de facto revolutionizing the assessment of standing balance. The aim of this work is to review the state-of-the-art literature that adopts this new posturographic paradigm, i.e., to analyse human postural sway through inertial sensors directly worn on the subject body. After a systematic search on PubMed and Scopus databases, two raters evaluated the quality of 73 full-text articles, selecting 47 high-quality contributions. A good inter-rater reliability was obtained (Cohen's kappa = 0.79). This selection of papers was used to summarize the available knowledge on the types of sensors used and their positioning, the data acquisition protocols and the main applications in this field (e.g., "active aging", biofeedback-based rehabilitation for fall prevention, and the management of Parkinson's disease and other balance-related pathologies), as well as the most adopted outcome measures. A critical discussion on the validation of wearable systems against gold standards is also presented.

Reliability and validity of the timed 360° turn test in people with multiple sclerosis

Objectives: To investigate (1) the intrarater, interrater, and test-retest reliability of the timed 360° turn test in people with Multiple Sclerosis (MS); (2) the minimum detectable change in the timed 360° turn test times; (3) the concurrent and discriminant validity of the timed 360° turn test times; and (4) the cut-off times that best discriminate people with MS from healthy people and fallers from non-fallers with MS.Method: Sixty-one people with MS (Expanded Disability Status Scale, EDSS, 0-6.5) and 34 healthy people were recruited in this cross-sectional study. The timed 360° turn test was administered along with the Timed Up and Go Test, Berg Balance Scale, Four Square Step Test, and EDSS by two independent raters.Results: The timed 360° turn test showed good intrarater, interrater, and test-retest reliability. Minimal detectable changes were 1.49 s and 1.53 s for the dominant and non-dominant sides, respectively. The timed 360° turn test was strongly correlated with other outcome measures. Significant differences in 360° turn times were found between people with MS and healthy people and between fallers and non-fallers with MS (p < .001 and p < .001, respectively). The cut-off times of 2.65 s on the dominant side and 2.42 s on the non-dominant best discriminated people with MS from healthy people, while 3.65 s on the dominant side and 3.75 s on the non-dominant best discriminated fallers from non-fallers with MS.Conclusions: The timed 360° turn test is a simple and reliable tool for assessing turning ability in MS.

Comparing Gait Trials with Greedy Template Matching

Gait assessment and quantification have received an increased interest in recent years. Embedded technologies and low-cost sensors can be used for the longitudinal follow-up of various populations (neurological diseases, elderly, etc.). However, the comparison of two gait trials remains a tricky question as standard gait features may prove to be insufficient in some cases. This article describes a new algorithm for comparing two gait trials recorded with inertial measurement units (IMUs). This algorithm uses a library of step templates extracted from one trial and attempts to detect similar steps in the second trial through a greedy template matching approach. The output of our method is a similarity index (SId) comprised between 0 and 1 that reflects the similarity between the patterns observed in both trials. Results on healthy and multiple sclerosis subjects show that this new comparison tool can be used for both inter-individual comparison and longitudinal follow-up.

Extended Timed Up & Go test: Is walking forward and returning back to the chair equivalent gait?

The Timed Up & Go test (TUG) is functional test and is a part of routine clinical examinations. The instrumented Timed Up & Go test enables its segmentation to sub-tasks: sit-to-stand, walking forward, turning, walking back, stand-to-sit, and consequently the computation of task-specific parameters and sub-tasks separately. However, there are no data on whether walking forward parameters differ from the walking back parameters. This study tested the differences between walking forward and walking back in the TUG extended to 10 m for 17 spatio-temporal gait parameters. All parameters were obtained from a GAITRite® pressure sensitive walkway (CIR Systems, Inc.). The differences were assessed for healthy controls and Parkinson's disease (PD) patients. None of investigated parameters exhibited a difference between both gait subtasks for healthy subjects group. Five parameters of interest, namely velocity, step length, stride length, stride velocity, and the proportion of the double support phase with respect to gait cycle duration, showed a statistically significant difference between gait for walking forward and walking back in PD patients. Therefore, we recommend a separate assessment for walking forward and walking back rather than averaging both gaits together.

Validation of magneto-inertial measuring units for measuring hip joint angles

Camera-based motion capture systems are the current gold standard for motion analysis. However, the use of wireless inertial sensor-based systems is increasing in popularity, largely due to convenient portability. The purpose of this study was to validate the use of wireless inertial sensors for measuring hip joint motion with a functional calibration requiring only one motion (walking) and neutral standing. Data were concurrently collected using a 10-camera motion capture system and a wireless inertial sensor-based system. Hip joint angles were measured for 10 participants during walking, jumping jack, and bilateral squat tasks and for a subset (n = 5) a jump turn task. Camera-based system hip joint angles were calculated from retro-reflective marker positions and sensor-based system angles were calculated in MATLAB using the sensor output quaternions. Most hip joint angles measured with the sensor-based system were within 6° of angles measured with the camera motion capture system. Accurate measurement of motion outside of a laboratory setting has broad implications for diagnosing movement abnormalities, monitoring sports performance, and assessing rehabilitation progress.

The ability of the instrumented tandem walking tests to discriminate fully ambulatory people with MS from healthy adults

BACKGROUND

People with multiple sclerosis (PwMS) experience walking and balance deficits at the initial phases of the disease, even when classified as only minimally disabled. Complex balance tasks, such as tandem walking, are probably more sensitive in detecting mild balance difficulties compared to the standard traditional tests in this population.

RESEARCH QUESTION

The aim was to investigate different types of 3-meter tandem walking tests in fully ambulatory PwMS.

METHODS

This observational case-control study included 50 participants; 25 PwMS, 17 women and 8 men, aged 35.2 (S.D = 8.6) and 25 healthy subjects, 18 women and 7 men, aged 34.3 (S.D = 6.1). The 3-meter tandem walk tests were performed during a single session. Each subject completed a sequence of 3 consecutive tests under 3 different task conditions: normal tandem walking, backward tandem walking and cognitive tandem walking. Tandem walking tests were evaluated via three small, lightweight axial wearable accelerometers (APDM, Oregon, USA).

RESULTS

The mean EDSS for the MS group was 1.6 (S.D = 0.6) indicating minimal disability. PwMS walked slower and at a slower pace, with a prolonged double support and decreased swing phase compared to healthy subjects in normal and backward conditions. In contrast, during the cognitive task, non-significant differences were found in gait measures between the PwMS and the healthy controls. Significant differences were found between task conditions for all participants. All reduced their walking speed and walked at a slower pace in both the cognitive and backward conditions compared to the normal tandem walk condition. However, non-significant scores were found for the condition X group factor.

SIGNIFICANCE

The study provides new insights into the 3-meter tandem walk test. Findings should improve evaluation and training of dynamic balance in fully ambulatory PwMS.

A Survey of Assistive Technologies for Assessment and Rehabilitation of Motor Impairments in Multiple Sclerosis

Multiple sclerosis (MS) is a disease that affects the central nervous system, which consists of the brain and spinal cord. Although this condition cannot be cured, proper treatment of persons with MS (PwMS) can help control and manage the relapses of several symptoms. In this survey article, we focus on the different technologies used for the assessment and rehabilitation of motor impairments for PwMS. We discuss sensor-based and robot-based solutions for monitoring, assessment and rehabilitation. Among MS symptoms, fatigue is one of the most disabling features, since PwMS may need to put significantly more intense effort toward achieving simple everyday tasks. While fatigue is a common symptom across several neurological chronic diseases, it remains poorly understood for various reasons, including subjectivity and variability among individuals. To this end, we also investigate recent methods for fatigue detection and monitoring. The result of this survey will provide both clinicians and researchers with valuable information on assessment and rehabilitation technologies for PwMS, as well as providing insights regarding fatigue and its effect on performance in daily activities for PwMS.

Wearable-based electronics to objectively support diagnosis of motor impairments in school-aged children

Developmental coordination disorder (DCD) and attention-deficit hyperactivity disorder (ADHD) are neuro-developmental disorders, starting in childhood, which can affect the planning of movements and the coordination. We investigated how and in which measure a system based on wearable inertial measurement units (IMUs) can provide an objective support to the diagnosis of motor impairments in school-aged children. The IMUs measured linear and rotational movements of 37 schoolchildren, 7-10yo, 17 patients and 20 control subjects, during the execution of motor exercises, performed under medical and psychiatric supervision, to assess different aspects of the motor coordination. The measured motor parameters showed a high degree of significance in discriminating the ADHD/DCD patients from the healthy subjects, pointing out which motor tasks are worth focusing on. So, medical doctors have a novel key lecture to state a diagnosis, gaining in objectivity with respect to the standard procedures which mainly involve subjective human judgment. Differently to other works, we propose a novel approach in terms of number of used IMUs and of performed motor tasks. Moreover, we demonstrate the meaningful parameters to be considered as more discriminant in supporting the medical diagnosis.