Characterization of Walking in Mild Parkinson's Disease: Reliability, Validity and Discriminant Ability of the Six-Minute Walk Test Instrumented with a Single Inertial Sensor

Although the 6-Minute Walk Test (6MWT) is among the recommended clinical tools to assess gait impairments in individuals with Parkinson's disease (PD), its standard clinical outcome consists only of the distance walked in 6 min. Integrating a single Inertial Measurement Unit (IMU) could provide additional quantitative and objective information about gait quality complementing standard clinical outcome. This study aims to evaluate the test-retest reliability, validity and discriminant ability of gait parameters obtained by a single IMU during the 6MWT in subjects with mild PD. Twenty-two people with mild PD and ten healthy persons performed the 6MWT wearing an IMU placed on the lower trunk. Features belonging to rhythm and pace, variability, regularity, jerkiness, intensity, dynamic instability and symmetry domains were computed. Test-retest reliability was evaluated through the Intraclass Correlation Coefficient (ICC), while concurrent validity was determined by Spearman's coefficient. Mann-Whitney U test and the Area Under the receiver operating characteristic Curve (AUC) were then applied to assess the discriminant ability of reliable and valid parameters. Results showed an overall high reliability (ICC ≥ 0.75) and multiple significant correlations with clinical scales in all domains. Several features exhibited significant alterations compared to healthy controls. Our findings suggested that the 6MWT instrumented with a single IMU can provide reliable and valid information about gait features in individuals with PD. This offers objective details about gait quality and the possibility of being integrated into clinical evaluations to better define walking rehabilitation strategies in a quick and easy way.

A Newly Developed Exergame-Based Telerehabilitation System for Older Adults: Usability and Technology Acceptance Study

BACKGROUND

Telerehabilitation has gained significance as a tool to deliver and supervise therapy and training as effective as traditional rehabilitation methods yet more accessible and affordable. An exergame-based telerehabilitation system has recently been developed within the scope of the international Continuum-of-Care (COCARE) project. The system comprises training devices for use in clinics (Dividat Senso) and at home (Dividat Senso Flex), an assessment system, and a rehabilitation cockpit, and its focus lies on home-based motor-cognitive training, which is remotely managed by health care professionals (HPs).

OBJECTIVE

This study aims to analyze the usability, acceptance, and enjoyment of the COCARE system from the perspective of primary (older adults [OAs]) and secondary (HPs) end users.

METHODS

At 3 trial sites (located in Switzerland, Italy, and Cyprus), participants engaged in a single-session trial of the COCARE system, including testing of exergames and assessments. Mixed methods encompassing qualitative approaches (eg, think aloud) and quantitative measures (eg, Exergame Enjoyment Questionnaire [EEQ], System Usability Scale [SUS], and Unified Theory of Acceptance and Use of Technology [UTAUT] questionnaire) were used to analyze participants' perceptions of the system and identify potential barriers to its implementation in a home setting. In addition, the associations of performance during gameplay and assessments, demographics, and training motivation (Behavioral Regulation in Exercise Questionnaire-3 [BREQ-3]) with usability, acceptance, and enjoyment were explored.

RESULTS

A total of 45 OAs and 15 HPs participated in this study. The COCARE system achieved good acceptance ratings (OAs: 83%, range 36%-100% and HPs: 81%, range 63.8%-93.3% of the maximum score), and OAs indicated high enjoyment (mean 73.3, SD 12.7 out of 100 points in the EEQ) during the exergame session. The system's usability, assessed with the SUS, received scores of 68.1 (SD 18.8; OAs) and 70.7 (SD 12.3; HPs) out of 100 points, with substantial differences observed between the trial sites. Several requirements for improvement were identified. Commonly mentioned barriers to adoption included the movement-recognition sensitivity of the Senso Flex, its limited markings, and difficulties in understanding certain instructions for assessments and games. Performance in games and assessments showed the highest significant correlations with the SUS (Spearman ρ=0.35, P=.02 to ρ=0.52, P<.001). The BREQ-3 had significant correlations with all usability measures, thereby even large significant correlations with enjoyment (Spearman ρ=0.58; P<.001). Age had moderately significant correlations with the SUS (Spearman ρ=-0.35; P=.02) and the UTAUT total score (ρ=-0.35; P=.02) but no significant correlation with the EEQ. Concerning sex and years of education, no significant correlations were found.

CONCLUSIONS

The study's findings will inform the further development of the COCARE system toward a user-friendly and widely accepted version, enhancing cognitive and physical functions in OAs. Future randomized controlled trials should evaluate the system's feasibility and effectiveness.

Uncovering Subtle Gait Deterioration in People with Early-Stage Multiple Sclerosis Using Inertial Sensors: A 2-Year Multicenter Longitudinal Study

Limited longitudinal studies have been conducted on gait impairment progression overtime in non-disabled people with multiple sclerosis (PwMS). Therefore, a deeper understanding of gait changes with the progression of the disease is essential. The objective of the present study was to describe changes in gait quality in PwMS with a disease duration ≤ 5 years, and to verify whether a change in gait quality is associated with a change in disability and perception of gait deterioration. We conducted a multicenter prospective cohort study. Fifty-six subjects were assessed at baseline (age: 38.2 ± 10.7 years, Expanded Disability Status Scale (EDSS): 1.5 ± 0.7 points) and after 2 years, participants performed the six-minute walk test (6MWT) wearing inertial sensors. Quality of gait (regularity, symmetry, and instability), disability (EDSS), and walking perception (multiple sclerosis walking scale-12, MSWS-12) were collected. We found no differences on EDSS, 6MWT, and MSWS-12 between baseline and follow-up. A statistically significant correlation between increased EDSS scores and increased gait instability was found in the antero-posterior (AP) direction (r = 0.34, p = 0.01). Seventeen subjects (30%) deteriorated (increase of at least 0.5 point at EDSS) over 2 years. A multivariate analysis on deteriorated PwMS showed that changes in gait instability medio-lateral (ML) and stride regularity, and changes in ML gait symmetry were significantly associated with changes in EDSS (F = 7.80 (3,13), p = 0.003, R2 = 0.56). Moreover, gait changes were associated with a decrease in PwMS perception on stability (p < 0.05). Instrumented assessment can detect subtle changes in gait stability, regularity, and symmetry not revealed during EDSS neurological assessment. Moreover, instrumented changes in gait quality impact on subjects' perception of gait during activities of daily living.

Feasibility and Effectiveness of a Personalized Home-Based Motor-Cognitive Training Program in Community-Dwelling Older Adults: Protocol for a Pragmatic Pilot Randomized Controlled Trial

BACKGROUND

Exergame-based motor-cognitive training in older adults has been associated with improvements in physical, cognitive, and psychological functioning. The novel Cocare system (Dividat GmbH), developed through a user-centered design process, allows motor-cognitive training in a telerehabilitation setting. It includes (1) a stationary stepping platform for supervised exergame training (Dividat Senso; Dividat GmbH), (2) a home-based version (Dividat Senso Flex, which is a rollable pressure-sensitive mat; Dividat GmbH), (3) an assessment system (including motor-cognitive tests), and (4) a rehabilitation cockpit for remote training supervision and management.

OBJECTIVE

The aim of this study is to test the feasibility and effectiveness of this novel training system.

METHODS

A total of 180 older adults from Switzerland, Italy, and Cyprus aged ≥60 years with a prescription for rehabilitation are randomly allocated to an intervention group or a control group. Both groups continue with their usual care, whereas participants in the intervention group additionally perform a 2-week supervised exergame training program at rehabilitation centers, followed by a 10-week home training program under remote supervision. The assessment system is used to indicate the start level of each participant, and, in both intervention periods, standardized progression rules are applied. The measures of feasibility include adherence, attrition, exergame enjoyment, willingness to perform such a training program, and the number and types of help requests. Effectiveness is assessed in terms of cognitive and physical functioning, balance confidence, and quality of life.

RESULTS

Data collection started in February 2023 and is ongoing. Final measurements are expected to be performed in January 2024.

CONCLUSIONS

Owing to the user-centered design approach, the Cocare system is expected to be user-friendly and offers several novel features to cover the whole continuum of care. This pragmatic trial will provide valuable information regarding final necessary adaptations and subsequent implementation efforts.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05751551; https://www.clinicaltrials.gov/study/NCT05751551.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/49377.

Surface-Electromyography-Based Co-Contraction Index for Monitoring Upper Limb Improvements in Post-Stroke Rehabilitation: A Pilot Randomized Controlled Trial Secondary Analysis

Persons post-stroke experience excessive muscle co-contraction, and consequently the arm functions are compromised during the activities of daily living. Therefore, identifying instrumental outcome measures able to detect the motor strategy adopted after a stroke is a primary clinical goal. Accordingly, this study aims at verifying whether the surface electromyography (sEMG)-based co-contraction index (CCI) could be a new clinically feasible approach for assessing and monitoring patients' motor performance. Thirty-four persons post-stroke underwent clinical assessment and upper extremity kinematic analysis, including sEMG recordings. The participants were randomized into two treatment groups (robot and usual care groups). Ten healthy subjects provided a normative reference (NR). Frost's CCI was used to quantify the muscle co-contraction of three different agonist/antagonist muscle pairs during an object-placing task. Persons post-stroke showed excessive muscle co-contraction (mean (95% CI): anterior/posterior deltoid CCI: 0.38 (0.34-0.41) p = 0.03; triceps/biceps CCI: 0.46 (0.41-0.50) p = 0.01) compared to NR (anterior/posterior deltoid CCI: 0.29 (0.21-0.36); triceps/biceps CCI: 0.34 (0.30-0.39)). After robot therapy, persons post-stroke exhibited a greater improvement (i.e., reduced CCI) in proximal motor control (anterior/posterior deltoid change score of CCI: -0.02 (-0.07-0.02) p = 0.05) compared to usual care therapy (0.04 (0.00-0.09)). Finally, the findings of the present study indicate that the sEMG-based CCI could be a valuable tool in clinical practice.

Machine learning based estimation of dynamic balance and gait adaptability in persons with neurological diseases using inertial sensors

Poor dynamic balance and impaired gait adaptation to different contexts are hallmarks of people with neurological disorders (PwND), leading to difficulties in daily life and increased fall risk. Frequent assessment of dynamic balance and gait adaptability is therefore essential for monitoring the evolution of these impairments and/or the long-term effects of rehabilitation. The modified dynamic gait index (mDGI) is a validated clinical test specifically devoted to evaluating gait facets in clinical settings under a physiotherapist's supervision. The need of a clinical environment, consequently, limits the number of assessments. Wearable sensors are increasingly used to measure balance and locomotion in real-world contexts and may permit an increase in monitoring frequency. This study aims to provide a preliminary test of this opportunity by using nested cross-validated machine learning regressors to predict the mDGI scores of 95 PwND via inertial signals collected from short steady-state walking bouts derived from the 6-minute walk test. Four different models were compared, one for each pathology (multiple sclerosis, Parkinson's disease, and stroke) and one for the pooled multipathological cohort. Model explanations were computed on the best-performing solution; the model trained on the multipathological cohort yielded a median (interquartile range) absolute test error of 3.58 (5.38) points. In total, 76% of the predictions were within the mDGI's minimal detectable change of 5 points. These results confirm that steady-state walking measurements provide information about dynamic balance and gait adaptability and can help clinicians identify important features to improve upon during rehabilitation. Future developments will include training of the method using short steady-state walking bouts in real-world settings, analysing the feasibility of this solution to intensify performance monitoring, providing prompt detection of worsening/improvements, and complementing clinical assessments.

Dynamic balance during walking in people with multiple sclerosis: A cross-sectional study

Dynamic balance disorders are common impairments in People with Multiple Sclerosis (PwMS) leading to gait disorders and a higher risk of falling. However, the assessment of dynamic balance is still challenging and instrumented indexes provide objective and quantitative data of CoM movement and Base of Support, which are considered that are two key factors describing dynamic balance. This study aims at validating recent instrumented indexes based on the inverted pendulum model and characterizing dynamic balance disorders in PwMS. We clinically assessed 20 PwMS and we collected instrumented gait data through an optoelectronic system. Data from 20 Healthy Subjects (HS) were also considered as normative reference. Margin of Stability by HoF (MoS_Hof) and by Terry (MoS_Terry) at midstance, and Foot Placement Estimator (D_FPE) at heel strike were calculated in mediolateral (ML) and anteroposterior (AP) directions, for both less affected and most affected sides for PwMS and for dominant and non-dominant side for HS. MoS_HOF well discriminated between PwMS and HS, followed by MoS_TERRY in ML direction (Mos_HOF: PwMS = 130.0 ± 27.2 mm, HS = 106.5 ± 18.6 mm, p < 0.001, MoS_TERRY: PwMS = 75.1 ± 24.3 mm, HS = 56.5 ± 23.4 mm, p < 0.02). MoS_HOF and MoS_TERRY discriminated between sides in both directions in PwMS. D_FPE did not discriminate between groups and sides. Moderate correlations were found between all three indexes and clinical balance scales (from r = 0.02 to r = 0.66), energy recovery (from r = -0.77 to r = -0.11), single stance time (from r = -0.11 to r = 0.80) and step length (from r = -0.83 to r = -0.20). MoS_HOF resulted in the best index to describe dynamic balance disorders in PwMS: they keep CoM position far from the lateral and as close as possible to the anterior boundary of the Base of Support as preventive strategies to control balance perturbations. Furthermore, PwMS seem to use different preventive strategies in accordance with the specific lower limb impairments. This alters the physiological gait mechanisms increasing the energy expenditure and decreasing gait quality and dynamic balance.

Association of 7-Day Profiles of Motor Activity in Marital Dyads with One Component Affected by Parkinson's Disease

(1) Background: A noticeable association between the motor activity (MA) profiles of persons living together has been found in previous studies. Social actigraphy methods have shown that this association, in marital dyads composed of healthy individuals, is greater than that of a single person compared to itself. This study aims at verifying the association of MA profiles in dyads where one component is affected by Parkinson's disease (PD). (2) Methods: Using a wearable sensor-based social actigraphy approach, we continuously monitored, for 7 days, the activities of 27 marital dyads including one component with PD. (3) Results: The association of motor activity profiles within a marital dyad (cross-correlation coefficient 0.344) is comparable to the association of any participant with themselves (0.325). However, when considering the disease severity quantified by the UPDRS III score, it turns out that the less severe the symptoms, the more associated are the MA profiles. (4) Conclusions: Our findings suggest that PD treatment could be improved by leveraging the MA of the healthy spouse, thus promoting lifestyles also beneficial for the component affected by PD. The actigraphy approach provided valuable information on habitual functions and motor fluctuations, and could be useful in investigating the response to treatment.

Older adults' needs and requirements for a comprehensive exergame-based telerehabilitation system: A focus group study

Introduction

Telerehabilitation in older adults using information and communication technologies (ICTs) provides therapy, which is potentially equally effective as traditional rehabilitation, yet more accessible. This study aimed to analyze the needs and requirements of older adults (OA) and healthcare-professionals (HP) toward ICTs and telerehabilitation in general as well as toward a specific novel exergame-based telerehabilitation system (COCARE system, Dividat).

Materials and methods

The COCARE telerehabilitation system enables individual training based on exergames, as well as an assessment system and a digital centralized case management. Six focus groups with in total 34 participants were conducted. A mixed-methods approach was used comprising questionnaires and semi-structured interviews.

Results

Both OA and HP would engage to an exergame-based telerehabilitation program. Major motivating factors are the relevance of such a training for health and the entertainment component of exergames. Main requirements are simplification of the system, variety, a personalized training, a constantly available contact person, and comprehensive instructions for use. Besides, HP praised the system's motivational effect, but remained concerned about risk of falls and social isolation.

Conclusion

ICTs for telerehabilitation are accepted by OA and HP but should be adapted hardware- and software-wise to address OA' age-stemming vulnerabilities (e.g., risk of falls) and low ICT literacy.

Balance Impairments in People with Early-Stage Multiple Sclerosis: Boosting the Integration of Instrumented Assessment in Clinical Practice

The balance of people with multiple sclerosis (PwMS) is commonly assessed during neurological examinations through clinical Romberg and tandem gait tests that are often not sensitive enough to unravel subtle deficits in early-stage PwMS. Inertial sensors (IMUs) could overcome this drawback. Nevertheless, IMUs are not yet fully integrated into clinical practice due to issues including the difficulty to understand/interpret the big number of parameters provided and the lack of cut-off values to identify possible abnormalities. In an attempt to overcome these limitations, an instrumented modified Romberg test (ImRomberg: standing on foam with eyes closed while wearing an IMU on the trunk) was administered to 81 early-stage PwMS and 38 healthy subjects (HS). To facilitate clinical interpretation, 21 IMU-based parameters were computed and reduced through principal component analysis into two components, sway complexity and sway intensity, descriptive of independent aspects of balance, presenting a clear clinical meaning and significant correlations with at least one clinical scale. Compared to HS, early-stage PwMS showed a 228% reduction in sway complexity and a 63% increase in sway intensity, indicating, respectively, a less automatic (more conscious) balance control and larger and faster trunk movements during upright posture. Cut-off values were derived to identify the presence of balance abnormalities and if these abnormalities are clinically meaningful. By applying these thresholds and integrating the ImRomberg test with the clinical tandem gait test, balance impairments were identified in 58% of PwMS versus the 17% detected by traditional Romberg and tandem gait tests. The higher sensitivity of the proposed approach would allow for the direct identification of early-stage PwMS who could benefit from preventive rehabilitation interventions aimed at slowing MS-related functional decline during neurological examinations and with minimal modifications to the tests commonly performed.

Walking With Horizontal Head Turns Is Impaired in Persons With Early-Stage Multiple Sclerosis Showing Normal Locomotion

Background

Turning the head while walking (an action often required during daily living) is particularly challenging to maintain balance. It can therefore potentially reveal subtle impairments in early-stage people with multiple sclerosis who still show normal locomotion (NW-PwMS). This would help in identifying those subjects who can benefit from early preventive exercise aimed at slowing the MS-related functional decline.

Objectives

To analyze if the assessment of walking with horizontal head turns (WHHT) through inertial sensors can discriminate between healthy subjects (HS) and NW-PwMS and between NW-PwMS subgroups. To assess if the discriminant ability of the instrumented WHHT is higher compared to clinical scores. To assess the concurrent validity of the sensor-based metrics.

Methods

In this multicenter study, 40 HS and 59 NW-PwMS [Expanded Disability Status Scale (EDSS) ≤ 2.5, disease duration ≤ 5 years] were tested. Participants executed Item-6 of the Fullerton Advanced Balance scale-short (FAB-s) wearing three inertial sensors on the trunk and ankles. The item required to horizontally turn the head at a beat of the metronome (100 bpm) while walking. Signals of the sensors were processed to compute spatiotemporal, regularity, symmetry, dynamic stability, and trunk sway metrics descriptive of WHHT.

Results

Mediolateral regularity, anteroposterior symmetry, and mediolateral stability were reduced in NW-PwMS vs. HS (p ≤ 0.001), and showed moderate discriminant ability (area under the receiver operator characteristic curve [AUC]: 0.71–0.73). AP symmetry and ML stability were reduced (p ≤ 0.026) in EDSS: 2–2.5 vs. EDSS: 0–1.5 subgroup (AUC: 0.69–0.70). The number of NW-PwMS showing at least one abnormal instrumented metric (68%) was larger (p ≤ 0.002) than the number of participants showing abnormal FAB-s-Item6 (32%) and FAB-s clinical scores (39%). EDSS: 2–2.5 subgroup included more individuals showing abnormal instrumented metrics (86%) compared to EDSS: 0–1.5 subgroup (57%). The instrumented metrics significantly correlated with FAB-s-Item6 and FAB-s scores (|Spearman's r_s| ≥ 0.37, p < 0.001), thus demonstrating their concurrent validity.

Conclusion

The instrumented assessment of WHHT provided valid objective metrics that discriminated, with higher sensitivity than clinical scores, between HS and NW-PwMS and between EDSS subgroups. The method is a promising tool to complement clinical evaluation, and reveal subclinical impairments in persons who can benefit from early preventive rehabilitative interventions.

The effect of music-induced emotion on visual-spatial learning in people with Parkinson's disease: A pilot study

INTRODUCTION

Emotional states have been shown to influence cognitive processes including visual-spatial learning. Parkinson's Disease (PD), besides manifesting with the cardinal motor symptoms, presents cognitive and affective disturbances. Here we aimed at investigating whether manipulation of the emotional state by means of music was able to influence the performance of a visual-spatial learning task in a group of PD participants.

METHODS

Ten PD patients and 11 healthy elderly (ELD) were asked to perform a visual-spatial learning task while listening two musical pieces evoking a neutral emotion or fear. Targets were presented on a screen in a preset order over four blocks and subjects were asked to learn the sequence order by attending to the display. At the end of each block, participants were asked to verbally recall the sequence and a score was assigned (Verbal Score, VS).

RESULTS

Analysis of variance-type statistic test on the VS disclosed a significant effect of Music and sequence Blocks (p = 0.01 and p < 0.001, respectively) and a significant interaction between Group and sequence Blocks. Sequence learning occurred across the training period in both groups, but PD patients were slower than ELD and at the end of the training period learning performance was worse in PD with respect to ELD. In PD patients, like in ELD, fear-inducing music has a detrimental effect on visual-spatial learning performances, which are slower and decreased.

CONCLUSION

These findings confirm an impairment in visual-spatial learning in PD and indicates that the emotional state influences this learning ability similarly to healthy controls.

The Falls Efficacy Scale International is a valid measure to assess the concern about falling and its changes induced by treatments

OBJECTIVE

To test with the Rasch analysis the psychometric properties of the Falls Efficacy Scale International, a questionnaire for measuring concern about falling.

DESIGN

Longitudinal observational study, before-after rehabilitation.

SETTING

Inpatient rehabilitation.

SUBJECTS

A total of 251 neurological patients with balance impairment.

INTERVENTIONS

Physiotherapy and occupational therapy aimed at reducing the risk of falling.

MAIN MEASURES

Participants (median age, first-third quartile: 74.0, 65.5-80.5 years; stroke and polyneuropathy: 43% and 21% of the sample, respectively) received a balance assessment (Falls Efficacy Scale International included) pre- and post-rehabilitation. Rasch analysis was used to evaluate the Falls Efficacy Scale International. Differential item functioning, which assesses the measures' stability in different conditions (e.g. before vs. after treatment) and in different groups of individuals, was tested for several variables.

RESULTS

Patients suffered a moderate balance impairment (Mini-BESTest median score; first-third quartile: 15; 11-19), mild-moderate concern about falling (Falls Efficacy Scale International: 28; 21-37) and motor disability (Functional Independence Measure, motor domain: 70.0; 57.0-76.5). Falls Efficacy Scale International items fitted the Rasch model (range of infit and outfit mean square statistics: 0.8-1.32 and 0.71-1.45, respectively) and the questionnaire's reliability was satisfactory (0.87). No differential item functioning was found for treatment, gender, age and balance impairment. Differential item functioning was found for diagnosis and disability severity, but it is shown that it is not such as to bias measures.

CONCLUSIONS

Falls Efficacy Scale International ordinal scores can be turned into interval measures, i.e. measures of the type of temperature. Being differential item functioning-free for treatment, these measures can be safely used to compare concern about falling before and after rehabilitation, such as when interested in assessing the rehabilitation effectiveness.

Strategies for maintaining dynamic balance in persons with neurological disorders during overground walking

Maintaining a stable gait requires a dynamic balance control, that can be altered in persons with Multiple Sclerosis (MS), Stroke (ST), and Parkinson's disease (PD). The understanding of the strategy for Center of Mass (CoM) positioning adopted by patients during walking is important to be able to program treatments aimed at improving gait control and preventing falls. Forty-four persons with a mild-to-moderate neurological disorder (20 with MS, 14 with ST, 10 with PD) underwent clinical examination and gait analysis. Ten Healthy Subjects (HS) walking at matched speed provided the normative data. Dynamic balance was assessed using the margin of stability (MoS). It was calculated as the distance between the extrapolated Center of Pressure and the extrapolated CoM at mid-stance. The MoS values for lower limbs were calculated in patients and compared with speed-matched values of HS. Persons with neurological disorder showed increased MoS in the medio-lateral direction with respect to HS. Within-group comparison analysis showed a symmetry between lower limbs in HS (Mean (95%CI) [mm], dominant vs non-dominant limb, 43.3 (31.9-54.6) vs 42.9 (28.8-56.9)) and PD (less affected vs more affected limb, 71.1 (59.8-82.5) vs 72.5 (58.5-86.6)), while a significant asymmetry was found in MS (54.4 (46.4-62.4) vs 81.1 (71.2-91.1)) and ST (52.1 (42.6-61.7) vs 74.7 (62.8-86.6)) participants. The history of falls was comparable among PD, MS, and ST groups, and the MoS in the frontal plane showed a strong correlation with these records. Objective assessment of MoS revealed pathology-specific strategies showing different impacts in MS, ST, and PD on the ability to control CoM information to manage the balance between limbs during gait. MoS evaluation will provide useful information to address a tailored rehabilitation program and to monitor disease progression.

Instrumentally assessed gait quality is more relevant than gait endurance and velocity to explain patient-reported walking ability in early-stage multiple sclerosis

BACKGROUND AND PURPOSE

People with multiple sclerosis (PwMS) often report walking limitations even when the gold standard Expanded Disability Status Scale (EDSS) indicates normal walking endurance/autonomy. The present multicenter study on early-stage PwMS aims at analyzing which aspects are associated with patient-reported walking limitations measured with the 12-item Multiple Sclerosis Walking Scale (MSWS-12).

METHODS

Eighty-two PwMS (EDSS ≤ 2.5) were assessed using the Fullerton Advanced Balance Scale-short (FAB-s), the Fatigue Severity Scale (FSS) and the 6-min Walk Test (6MWT), the latter administered also to 21 healthy subjects. Participants performed the 6MWT wearing three inertial sensors on ankles and trunk. Instrumented metrics describing gait velocity (stride length and frequency) and quality (regularity, symmetry, instability) were computed from sensor data. Fatigue (FSS), balance (FAB-s), walking endurance (6MWT) and instrumented metrics were entered in a multiple regression model with MSWS-12 as dependent variable.

RESULTS

Gait symmetry, gait instability, fatigue and balance were significantly associated with self-rated walking ability, whilst walking endurance and velocity were not. Fatigue, balance, gait symmetry and instability were more impaired in participants reporting mild-to-moderate (MS_MM-PWL , 25 ≤ MSWS-12 < 75) compared to those reporting none-to-minimal (MS_nm-PWL , 0 ≤ MSWS-12 ≤ 25) perceived walking limitations. Compared to healthy subjects, gait symmetry and stability were reduced in MS_nm-PWL and MS_MM-PWL , even in those participants with EDSS ≤ 1.5.

CONCLUSION

Instrumentally assessed gait quality aspects (symmetry and instability) are associated with patient-reported walking ability in early-stage PwMS and seem sensitive biomarkers to detect subtle impairments even in the earliest stages of the disease (EDSS ≤ 1.5). Future studies should assess their ability to follow walking change due to MS progression or pharmacological/rehabilitation 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.

Sequentially applied myoelectrically controlled FES in a task-oriented approach and robotic therapy for the recovery of upper limb in post-stroke patients: A randomized controlled pilot study

BACKGROUND

Functional recovery of the plegic upper limb in post-stroke patients may be enhanced by sequentially applying a myoelectrically controlled FES (MeCFES), which allows the patient to voluntarily control the muscle contraction during a functional movement, and robotic therapy which allows many repetitions of movements.

OBJECTIVE

Evaluate the efficacy of MeCFES followed by robotic therapy compared to standard care arm rehabilitation for post-stroke patients.

METHODS

Eighteen stroke subjects (onset ⩾ 3 months, age 60.1 ± 15.5) were recruited and randomized to receive an experimental combination of MeCFES during task-oriented reaching followed by robot therapy (MRG) or same intensity conventional rehabilitation care (CG) aimed at the recovery of the upper limb (20 sessions/45 minutes). Change was evaluated through Fugl-Meyer upper extremity (FMA-UE), Reaching Performance Scale and Box and Block Test.

RESULTS

The experimental treatment resulted in higher improvement on the FMA-UE compared with CG (P= 0.04), with a 10-point increase following intervention. Effect sizes were moderate in favor of the MRG group on FMA-UE, FMA-UE proximal and RPS (0.37-0.56).

CONCLUSIONS

Preliminary findings indicate that a combination of MeCFES and robotic treatment may be more effective than standard care for recovery of the plegic arm in persons > 3 months after stroke. The mix of motor learning techniques may be important for successful rehabilitation of arm function.

Improved Gait of Persons With Multiple Sclerosis After Rehabilitation: Effects on Lower Limb Muscle Synergies, Push-Off, and Toe-Clearance

Introduction: Persons with MS (PwMS) have markedly reduced push-off and toe-clearance during gait compared to healthy subjects (HS). These deficits may result from alterations in neuromotor control at the ankle. To optimize rehabilitation interventions for PwMS, a crucial step is to evaluate if and how altered neuromotor control, as represented by muscle synergies, improves with rehabilitation. In this study we investigated changes in ankle motor control and associated biomechanical parameters during gait in PwMS, occurring with increase in speed after gait rehabilitation. Methods: 3D motion and EMG data were collected while 11 PwMS (age 50.3 + 11.1; EDSS 5.2 + 1.2) walked overground at self-selected speed before (T0) and after 20 sessions (T1) of intensive treadmill training. Muscle synergies were extracted using non-negative matrix factorization. Gait parameters were computed according to the LAMB protocol. Pearson's correlation coefficient was used to evaluate the similarity of motor modules between PwMS and HS. To assess differences in distal module activations representing neuromotor control at the ankle [Forward Propulsion (FPM) and Ground Clearance modules (GCM)], each module's activation timing was integrated over 100% of the gait cycle and the activation percentage index (API) was computed in six phases. Ten age matched HS provided two separate speed-matched normative datasets for T0 and T1. For speed independent comparison for the PwMs Z scores were calculated for all their gait variables. Results: In PwMS velocity increased significantly from T0 to T1 (0.74-0.90 m/s, p < 0.05). The activation profiles (API) of FPM and GCM of PwMS improved in pre-swing (p < 0.05): FPM (Mean [95% CI] [%]: T0: 12.5 [5.7-19.3] vs. T1: 9.0 [2.7-15.3]); GCM (T0: 26.7 [18.2-35.3] vs. T1: 24.5 [18.2-30.7]). This was associated with an increase in toe clearance (80.3 to 103.6 mm, p < 0.05) and a higher ankle power peak in pre-swing (1.53-1.93 W/kg, p < 0.05). Conclusion: Increased gait speed of PwMS after intensive gait training was consistent with improvements in spatio-temporal gait parameters. The most important finding of this study was the re-organization of distal leg modules related to neurophysiological changes induced by rehabilitation. This was associated with an improved ankle performance.

Haptic vs sensorimotor training in the treatment of upper limb dysfunction in multiple sclerosis: A multi-center, randomised controlled trial

BACKGROUND

In multiple sclerosis (MS) exercise improves upper limb functions, but it is unclear what training types are more effective.

OBJECTIVE

This study compares robot-assisted training based on haptic or sensorimotor exercise.

METHODS

41clinically definite MS subjects with upper limb impairment were randomised into two groups: (i) Haptic and (ii) Sensorimotor. Subjects in the Haptic performed a robot-assisted training protocol designed to counteract incoordination and weakness. The task -interaction with a virtual mass-spring system against a resistive load- requires coordination skills. Task difficulty and magnitude of resistive load were automatically adjusted to the individual impairment. Subjects in the Sensorimotor performed reaching movements under visual control; the robot generated no forces. Both groups underwent eight training sessions (40 min/session, 2 sessions/week). Treatment outcome were 9HPT and ARAT scores.

RESULTS

The average 9HPT score decreased from 74±9 s to 61±8 s for the Haptic and from 49±6 s to 44±6 s. We found a significant Treatment (p=.0453) and Time differences (p=.005), but no significant Treatment×Time interactions although we found that the absolute change was only significant in the Haptic group (p=.011). We observed no significant changes in the ARAT score. Participants tolerated treatments well with a low drop-out rate. In the subjects evaluated at after 12 week (11 subject in sensory-motor and 17 in haptic group) no retention of the effect was found.

CONCLUSIONS

Task oriented training may improve upper limb function in persons with MS especially in prevalent pyramidal impaired subjects without maintain the effects after three months.

CLINICAL TRIAL REGISTRATION NUMBER

NCT02711566 (clinicaltrial.gov).

Effects of robot therapy on upper body kinematics and arm function in persons post stroke: a pilot randomized controlled trial

BACKGROUND

Robot-based rehabilitation for persons post-stroke may improve arm function and daily-life activities as measured by clinical scales, but its effects on motor strategies during functional tasks are still poorly investigated. This study aimed at assessing the effects of robot-therapy versus arm-specific physiotherapy in persons post-stroke on motor strategies derived from upper body instrumented kinematic analysis, and on arm function measured by clinical scales.

METHODS

Forty persons in the sub-acute and chronic stage post-stroke were recruited. This sample included all those subjects, enrolled in a larger bi-center study, who underwent instrumented kinematic analysis and who were randomized in Center 2 into Robot (R_Group) and Control Group (C_Group). R_Group received robot-assisted training. C_Group received arm-specific treatment delivered by a physiotherapist. Pre- and post-training assessment included clinical scales and instrumented kinematic analysis of arm and trunk during a virtual untrained task simulating the transport of an object onto a shelf. Instrumented outcomes included shoulder/elbow coordination, elbow extension and trunk sagittal compensation. Clinical outcomes included Fugl-Meyer Motor Assessment of Upper Extremity (FM-UE), modified Ashworth Scale (MAS) and Functional Independence Measure (FIM).

RESULTS

R_Group showed larger post-training improvements of shoulder/elbow coordination (Cohen's d = - 0.81, p = 0.019), elbow extension (Cohen's d = - 0.71, p = 0.038), and trunk movement (Cohen's d = - 1.12, p = 0.002). Both groups showed comparable improvements in clinical scales, except proximal muscles MAS that decreased more in R_Group (Cohen's d = - 0.83, p = 0.018). Ancillary analyses on chronic subjects confirmed these results and revealed larger improvements after robot-therapy in the proximal portion of FM-UE (Cohen's d = 1.16, p = 0.019).

CONCLUSIONS

Robot-assisted rehabilitation was as effective as arm-specific physiotherapy in reducing arm impairment (FM-UE) in persons post-stroke, but it was more effective in improving motor control strategies adopted during an untrained task involving vertical movements not practiced during training. Specifically, robot therapy induced larger improvements of shoulder/elbow coordination and greater reduction of abnormal trunk sagittal movements. The beneficial effects of robot therapy seemed more pronounced in chronic subjects. Future studies on a larger sample should be performed to corroborate present findings.

TRIAL REGISTRATION

www.ClinicalTrials.gov NCT03530358. Registered 21 May 2018. Retrospectively registered.

Human kinematic, kinetic and EMG data during different walking and stair ascending and descending tasks

This paper reports the kinematic, kinetic and electromyographic (EMG) dataset of human locomotion during level walking at different velocities, toe- and heel-walking, stairs ascending and descending. A sample of 50 healthy subjects, with an age between 6 and 72 years, is included. For each task, both raw data and computed variables are reported including: the 3D coordinates of external markers, the joint angles of lower limb in the sagittal, transversal and horizontal anatomical planes, the ground reaction forces and torques, the center of pressure, the lower limb joint mechanical moments and power, the displacement of the whole body center of mass, and the surface EMG signals of the main lower limb muscles. The data reported in the present study, acquired from subjects with different ages, represents a valuable dataset useful for future studies on locomotor function in humans, particularly as normative reference to analyze pathological gait, to test the performance of simulation models of bipedal locomotion, and to develop control algorithms for bipedal robots or active lower limb exoskeletons for rehabilitation.

Measures of dynamic balance during level walking in healthy adult subjects: Relationship with age, anthropometry and spatio-temporal gait parameters

The maintenance of balance in dynamic conditions (e.g. during walking) is a necessary requirement that motor control must reach to avoid falls. However, this is a challenging situation, since to ensure the forward progression of the body, the center of mass must stay outside the base of support in the sagittal plane, and simultaneously remain inside the lateral borders in the frontal plane. Deviation from normative data of healthy subjects in dynamic balance could be used to quantify gait stability, fall risk and to provide hints for rehabilitation. However, normative data can be influenced by age, sex, anthropometry and spatio-temporal gait parameters, and such differences among subjects and leg side can hamper accurate assessment. The aims of this study were to investigate, in a group of healthy subjects: (1) possible asymmetry in dynamic balance maintenance strategies between leg sides, (2) the influence of age, sex and anthropometry on stability and (3) its dependence by spatio-temporal gait parameters. A total of 34 healthy subjects aged between 21 and 71 years, and ranging from 50.1 to 101.6 kg of body mass and from 155.0 to 188.9 cm of height were assessed on spatio-temporal and dynamic balance parameters (Foot Placement Estimator at heel strike and Margin of Stability at mid-stance) during self-selected gait. No parameter showed differences between legs. Dynamic balance parameters were influenced by sex, age, body mass and height mainly in the frontal plane. These measures were also correlated with gait speed and stride length both in the antero-posterior and medio-lateral directions. In addition also cadence and step width influenced the stability in the sagittal and frontal planes, respectively. The findings of this study confirm the symmetry in motor control of dynamic balance during self-selected gait in healthy subjects. Sex, anthropometry and spatio-temporal gait parameters have a significant effect on stability parameters, and this should be taken into account in dynamic balance studies.

How Tool-Use Shapes Body Metric Representation: Evidence From Motor Training With and Without Robotic Assistance

Previous evidence has shown that tool-use can reshape one's own body schema, extending peripersonal space and modulating the representation of related body parts. Here, we investigated the role of tool action in shaping the body metric representation, by contrasting two different views. According to a first view, the shaping would rely on the mere execution of tool action, while the second view suggests that the shaping induced by tool action on body representation would primarily depend on the representation of the action goals to be accomplished. To this aim, we contrasted a condition in which participants voluntarily accomplish the movement by representing the program and goal of a tool action (i.e., active tool-use training) with a condition in which the tool-use training was produced without any prior goal representation (i.e., passive tool-use training by means of robotic assistance). If the body metric representation primarily depends on the coexistence between goal representation and bodily movements, we would expect an increase of the perceived forearm length in the post- with respect to the pre-training phase after the active training phase only. Healthy participants were asked to estimate the midpoint of their right forearm before and after 20 min of tool-use training. In the active condition, subjects performed "enfold-and-push" movements using a rake to prolong their arm. In the passive condition, subjects were asked to be completely relaxed while the movements were performed with robotic assistance. Results showed a significant increase in the perceived arm length in the post- with respect to the pre-training phase only in the active task. Interestingly, only in the post-training phase, a significant difference was found between active and passive conditions, with a higher perceived arm length in the former than in the latter. From a theoretical perspective, these findings suggest that tool-use may shape body metric representation only when action programs are motorically represented and not merely produced. From a clinical perspective, these results support the use of robots for the rehabilitation of brain-damaged hemiplegic patients, provided that robot assistance during the exercises is present only "as-needed" and that patients' motor representation is actively involved.

WITHDRAWN: Assessment of the inter-laboratory repeatability of gait analysis measurements in patients with multiple sclerosis

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Instrumented Version of the Modified Dynamic Gait Index in Patients With Neurologic Disorders

BACKGROUND

Gait instability is common in adults with neurologic disorders and the modified Dynamic Gait Index (mDGI) was recently introduced to assess dynamic balance. However, instrumental assessment is needed to provide quantitative measures.

OBJECTIVE

To develop and validate an instrumented version of the mDGI.

DESIGN

Cross-sectional study.

SETTING

Clinical setting.

PARTICIPANTS

Thirty adults with neurologic disorders (10 with multiple sclerosis, 10 with Parkinson disease, and 10 with stroke) and 20 healthy volunteers.

METHODS

Participants were assessed with the Timed Up and Go test (TUG) and with the mDGI. During the assessment of mDGI, data were collected by a single Inertial Measurement Unit (IMU) positioned on the sternum. Principal component analysis (PCA) was performed on the instrumented data extracting eight PC scores (ImPC) describing dynamic balance. The instrumented overall score (ImDGI) was then calculated as the sum of the mPCs. PCA revealed two components associated with stride features and regularity (ImDGI_Gait_Pattern) and trunk movements (ImDGI_Trunk_Sway). Spearman coefficients were calculated between mDGI and ImDGI, whereas Mann-Whitney (U) and Kruskal-Wallis (H) tests assessed differences between groups and neurologic conditions.

MAIN OUTCOME MEASUREMENTS

ImDGI.

RESULTS

ImDGI did not show ceiling effects, and good correlations were found between ImDGI and mDGI (r = .84), and TUG (r = .84) for people with neurologic disorders (P < .001). Significant differences among pathologies (H test₍₂₎ =12.5, P = .002) and between healthy participants and adults with neurologic disorders (U test = 47.0, P = .001) were found. ImDGI_Trunk_Sway discriminated between people using or not using walking aids and among the three pathologies (H₍₂₎ = 10.0, P = .007).

CONCLUSIONS

The ImDGI test seems to provide valid measures to objectively assess dynamic balance in neurologic conditions and possibly quantify balance deficits also in adults with neurologic disorders.

The LAMB gait analysis protocol: Definition and experimental assessment of operator-related variability

Gait analysis has demonstrated to efficaciously support clinical investigations. The patterns of the outcome variables (joint angles, moments and powers) are characterized by an intrinsic and extrinsic variability. Particularly, extrinsic variability is induced by operator-dependent differences in markers' placement, with errors propagating non-linearly to alter outcome variable patterns. The aims of this study are (1) to consider a specific gait analysis protocol named LAMB and provide a description of its procedures, (2) to experimentally assess the between-operator and within-operator variability induced by operator-dependent marking of required anatomical landmarks and (3) to evidence how such inaccuracies propagates to the gait analysis kinematic and kinetic outcome variables. Six expert gait analysis operators performed LAMB anatomical landmarks marking on three healthy adult participants; moreover, one operator repeated three times the marking on one participant. The participants then performed a set of locomotor tasks including stair negotiation and heel- and toe-walking. An anatomical calibration approach let to register each marking and to compute, starting from one single raw data set, a set of outcome variables for each marking/operator. The between-operator variability of gait analysis outcome was assessed in terms of mean absolute variability to quantify offsets and minimal correlation coefficient to quantify patterns' similarity. The results evidence average minimal correlation coefficient ranging from 0.857 for moments to 0.907 for angles and average mean absolute variability accounted for few degrees in angular variables (worst between-operator mean absolute variability is 7.3°), while dynamic variables mean absolute variability, relative to the variable range, was below 5% for moment and below 10% for powers. The variability indexes are comparable to those related to previously published protocols and are independent from the considered task, thus suggesting that the LAMB is a reliable protocol suitable for the analysis of different locomotor tasks.

Predictors of mobility domain of health-related quality of life after rehabilitation in Parkinson's disease: a pilot study

Background

Parkinson’s disease impacts health-related quality of life (HRQoL), however no studies inquired on predictors of HRQoL changes after rehabilitation. This study assessed the relationship between mobility domain of HRQoL measured by Parkinson’s Disease Questionnaires-39 (PDQ-39) and clinical-demographic characteristics and developed a model predicting changes after rehabilitation.

Methods

Subjects with Parkinson’s disease underwent rehabilitation treatment and completed the following predictors: 10-m walking test (10MWT), Timed Up and Go (TUG), Berg Balance scale (BBS), Activities-specific Balance Confidence scales (ABC), Freezing of Gait (FOGQ) and PDQ-39. Two general linear models were calculated to predict the relationship between HRQoL at baseline and to predict HRQoL changes after rehabilitation.

Results

Forty-two subjects (age 74.9 ± 7.3 years, Hoehn&Yahr 2.8 ± 0.6) completed the baseline evaluation. The first model (multiple R² = 0.59, F = 5.86, P < 0.001) showed that ABC (B = − 0.51, CI = − 0.86 to 0.15, R² = 0.41, P = 0.005) and FOGQ (B = 2.38, CI = 1.03 to 3.73, R² = 0.07, P = 0.001) were statistically significant predictors of mobility aspect of HRQoL at baseline. Thirty seven subjects completed the rehabilitation sessions, data were entered in the second model (multiple R² = 0.40, F = 4.24, P < 0.004) showing that gender (B = − 5.12, CI = − 9.86 to − 0.39, R² = 0.23, P = 0.034), Hoehn&Yahr (B = 10.93, CI = + 3.27 to + 18.61, R² = 0.22, P = 0.006) and PDQ-39 mobility at baseline (B = − 0.38, CI = − 0.63 to − 0.14, R² = 0.55, P = 0.002) were statistically significant predictors of changes of the mobility aspect of HRQoL.

Conclusions

Balance confidence and Freezing of Gait are associated with the mobility aspect of HRQoL. Changes in mobility domain of HRQoL (as assessed by PDQ-39) are likely to be greater in males, in people at higher stages of the disease and in people with more severe limitation in mobility domain of HRQoL (as assessed by PDQ-39) before rehabilitation. Results might be different when considering different outcomes or different measures for the same outcome (performance mobility test instead of self-report questionnaires). Further investigations are needed to better understand other components of HRQoL in addition to mobility.

Trial registration

NCT02713971 registered March 8, 2016.

Instrumental Assessment of Stair Ascent in People With Multiple Sclerosis, Stroke, and Parkinson's Disease: A Wearable-Sensor-Based Approach

Stair ascent is a challenging daily-life activity highly related to independence. This task is usually assessed with clinical scales suffering from partial subjectivity and limited detail in evaluating different task aspects. In this paper, we instrumented the assessment of stair ascent in people with multiple sclerosis (MS), stroke (ST), and Parkinson's disease (PD) to analyze the validity of the proposed quantitative indexes and characterize subjects' performances. Participants climbed 10 steps wearing a magneto-inertial sensor [magneto-inertial measurement unit (MIMU)] at sternum level. Gait pattern features (step frequency, symmetry, regularity, and harmonic ratios), and upper trunk sway were computed from MIMU signals. Clinical modified dynamic gait index (mDGI) and mDGI-Item 8 "Up stairs" were administered. Significant correlations with clinical scores were found for gait pattern features ( ) and trunk pitch sway ( ) demonstrating their validity. Instrumental indexes showed alterations in the three pathological groups compared to healthy subjects and significant differences, not clinically detected, among MS, ST, and PD. MS showed the worst performance, with alterations of all gait pattern aspects and larger trunk pitch sway. ST showed worsening in gait pattern features but not in trunk motion. PD showed fewer alterations consisting in reduced step frequency and trunk yaw sway. These results suggest that the use of an MIMU provided valid objective indexes revealing between-group differences in stair ascent not detected by clinical scales. Importantly, the indexes include upper trunk measures, usually not present in clinical tests, and provide relevant hints for tailored rehabilitation.

Counteracting Postural Perturbations Through Body Weight Shift: a Pilot Study Using a Robotic Platform in Subjects with Parkinson's Disease

Abnormalities of body-weight transfer occur during several motor tasks in people with Parkinson's disease (PwPD). In this study, a novel robotic paradigm for assessment and training of dynamic balance was developed and applied to twelve healthy subjects (HS) and ten PwPD to verify its feasibility and to assess the capability of PwPD to counteract postural perturbations through body-weight shifts. At variance with other robotic paradigms, subjects had to react as fast as possible to the perturbation, bringing the platform back to the horizontal and keeping it until the end of the task. Four randomized perturbations, obtained varying the platform equilibrium angle from 0° to ±6° in sagittal (backward, forward) and frontal (right, left) planes, were repeated 3 times. Compared to HS, PwPD showed, in all perturbation directions, increased delay in counteraction phase onset (p<=0.01), prolonged time to stabilize the platform (p<=0.02), and higher deviation of the final plate inclination from the horizontal (p<=0.04), the deviation being larger during sagittal perturbations. PwPD showed also larger (p=0.01) postural sway around the stabilization angle following frontal perturbations. Results are in keeping with known hypo- and bradykinesia as well as proprioceptive and kinesthetic impairments in PD. We suggest that the proposed approach is feasible and might be included in balance evaluation and training in PD.

The Dominant-Subthalamic Nucleus Phenomenon in Bilateral Deep Brain Stimulation for Parkinson's Disease: Evidence from a Gait Analysis Study

Background

It has been suggested that parkinsonian [Parkinson’s disease (PD)] patients might have a “dominant” (DOM) subthalamic nucleus (STN), whose unilateral electrical stimulation [deep brain stimulation (DBS)] could lead to an improvement in PD symptoms similar to bilateral STN-DBS.

Objectives

Since disability in PD patients is often related to gait problems, in this study, we wanted to investigate in a group of patients bilaterally implanted for STN-DBS: (1) if it was possible to identify a subgroup of subjects with a dominant STN; (2) in the case, if the unilateral stimulation of the dominant STN was capable to improve gait abnormalities, as assessed by instrumented multifactorial gait analysis, similarly to what observed with bilateral stimulation.

Methods

We studied 10 PD patients with bilateral STN-DBS. A clinical evaluation and a kinematic, kinetic, and electromyographic (EMG) analysis of overground walking were performed—off medication—in four conditions: without stimulation, with bilateral stimulation, with unilateral right or left STN-DBS. Through a hierarchical agglomerative cluster analysis based on motor Unified Parkinson’s Disease Rating Scale scores, it was possible to separate patients into two groups, based on the presence (six patients, DOM group) or absence (four patients, NDOM group) of a dominant STN.

Results

In the DOM group, both bilateral and unilateral stimulation of the dominant STN significantly increased gait speed, stride length, range of motion of lower limb joints, and peaks of moment and power at the ankle joint; moreover, the EMG activation pattern of distal leg muscles was improved. The unilateral stimulation of the non-dominant STN did not produce any significant effect. In the NDOM group, only bilateral stimulation determined a significant improvement of gait parameters.

Conclusion

In the DOM group, the effect of unilateral stimulation of the dominant STN determined an improvement of gait parameters similar to bilateral stimulation. The pre-surgical identification of these patients, if possible, could allow to reduce the surgical risks and side effects of DBS adopting a unilateral approach.

Multidisciplinary Rehabilitation is Efficacious and Induces Neural Plasticity in Multiple Sclerosis even when Complicated by Progressive Multifocal Leukoencephalopathy

A 48-year-old woman with multiple sclerosis (MS), treated with natalizumab for more than one year without clinical and magnetic resonance imaging (MRI) signs of disease activity, was diagnosed with definite progressive multifocal leukoencephalopathy (PML). She presented with subacute motor deficit of the right upper limb (UL), followed by involvement of the homolateral leg and urinary urgency. The patient was treated with steroids and plasma exchange. On follow-up MRI scans, the PML lesion remained stable and no MS rebounds were observed, but the patient complained of a progressive worsening of the right UL motor impairment, becoming dependent in most activities of daily living. A cycle of multidisciplinary rehabilitation (MDR) was then started, including daily sessions of UL robot therapy and occupational therapy. Functional MRI (fMRI) was acquired before and at the end of the MDR cycle using a motor task which consisted of 2 runs: in one run the patient was asked to observe while the second one consisted of hand grasping movements. At the end of the rehabilitation period, both the velocity and the smoothness of arm trajectories during robot-based reaching movements were significantly improved. After MDR, compared with baseline, fMRI showed significantly increased functional activation within the sensory-motor network in the active, motor task, while no significant differences were found in the observational task. MDR in MS, including robot-assisted UL training, seems to be clinically efficacious and to have a significant impact on brain functional reorganization on a short-term, even in the presence of superimposed tissue damage provoked by PML.

Investigation of Anticipatory Postural Adjustments during One-Leg Stance Using Inertial Sensors: Evidence from Subjects with Parkinsonism

The One-Leg Stance (OLS) test is a widely adopted tool for the clinical assessment of balance in the elderly and in subjects with neurological disorders. It was previously showed that the ability to control anticipatory postural adjustments (APAs) prior to lifting one leg is significantly impaired by idiopathic Parkinson’s disease (iPD). However, it is not known how APAs are affected by other types of parkinsonism, such as frontal gait disorders (FGD). In this study, an instrumented OLS test based on wearable inertial sensors is proposed to investigate both the initial anticipatory phase and the subsequent unipedal balance. The sensitivity and the validity of the test have been evaluated. Twenty-five subjects with iPD presenting freezing of gait (FOG), 33 with iPD without FOG, 13 with FGD, and 32 healthy elderly controls were recruited. All subjects wore three inertial sensors positioned on the posterior trunk (L4–L5), and on the left and right frontal face of the tibias. Participants were asked to lift a foot and stand on a single leg as long as possible with eyes open, as proposed by the mini-BESTest. Temporal parameters and trunk acceleration were extracted from sensors and compared among groups. The results showed that, regarding the anticipatory phase, the peak of mediolateral trunk acceleration was significantly reduced compared to healthy controls (p < 0.05) in subjects with iPD with and without FOG, but not in FGD group (p = 0.151). Regarding the balance phase duration, a significant shortening was found in the three parkinsonian groups compared to controls (p < 0.001). Moreover, balance was significantly longer (p < 0.001) in iPD subjects without FOG compared to subjects with FGD and iPD subjects presenting FOG. Strong correlations between balance duration extracted by sensors and clinical mini-BESTest scores were found (ρ > 0.74), demonstrating the method’s validity. Our findings support the validity of the proposed method for assessing the OLS test and its sensitivity in distinguishing among the tested groups. The instrumented test discriminated between healthy controls and people with parkinsonism and among the three groups with parkinsonism. The objective characterization of the initial anticipatory phase represents an interesting improvement compared to most clinical OLS tests.

Gait initiation is impaired in subjects with Parkinson's disease in the OFF state: Evidence from the analysis of the anticipatory postural adjustments through wearable inertial sensors

People with Parkinson's disease (PD) typically demonstrate impaired anticipatory postural adjustments (APAs) that shift the body center of mass forward (imbalance) and over the stance leg (unloading) prior to gait initiation. APAs are known to be smallest when people with PD are in their OFF-medication state compared to ON-medication or healthy controls. The aim of this pilot study is to validate a previously developed method for the assessment of gait initiation on PD patients in OFF state with body-worn, inertial sensors. Ten subjects with mild-to-moderate idiopathic PD and twelve healthy controls of similar age performed three gait initiation trials. The spatio-temporal parameters of APAs were extracted from three wearable sensors, placed on the shins and on the lower back, and validated with two force plates. Temporal parameters extracted from sensors and force plates, as well as the trunk medio-lateral acceleration and the correspondent displacement of the center of pressure, were significantly correlated. Subjects with PD showed hypometric adjustments in the medio-lateral direction (p-value<0.003) and increased duration of the unloading phase (p-value=0.04). The unloading phase was significantly longer than the imbalance (p-value=0.003) only in subjects with PD. The validity of the method of quantifying APAs from inertial sensors was confirmed in PD subjects by comparison with force plates. Sensitivity in discriminating PD patients from healthy controls was proven by both spatial and temporal parameters. Objective measures of gait initiation deficits with wearable technology provides valuable instrument for the assessment of gait initiation in clinical environments.

Wearable Sensor-Based Biofeedback Training for Balance and Gait in Parkinson Disease: A Pilot Randomized Controlled Trial

OBJECTIVES

To analyze the feasibility and efficacy of a novel system (Gamepad [GAMing Experience in PArkinson's Disease]) for biofeedback rehabilitation of balance and gait in Parkinson disease (PD).

DESIGN

Randomized controlled trial.

SETTING

Clinical rehabilitation gym.

PARTICIPANTS

Subjects with PD (N=42) were randomized into experimental and physiotherapy without biofeedback groups.

INTERVENTIONS

Both groups underwent 20 sessions of training for balance and gait. The experimental group performed tailored functional tasks using Gamepad. The system, based on wearable inertial sensors, provided users with real-time visual and acoustic feedback about their movement during the exercises. The physiotherapy group underwent individually structured physiotherapy without feedback.

MAIN OUTCOME MEASURES

Assessments were performed by a blinded examiner preintervention, postintervention, and at 1-month follow-up. Primary outcomes were the Berg Balance Scale (BBS) and 10-m walk test (10MWT). Secondary outcomes included instrumental stabilometric indexes and the Tele-healthcare Satisfaction Questionnaire.

RESULTS

Gamepad was well accepted by participants. Statistically significant between-group differences in BBS scores suggested better balance performances of the experimental group compared with the physiotherapy without biofeedback group both posttraining (experimental group-physiotherapy without biofeedback group: mean, 2.3±3.4 points; P=.047) and at follow-up (experimental group-physiotherapy without biofeedback group: mean, 2.7±3.3 points; P=.018). Posttraining stabilometric indexes showed that mediolateral body sway during upright stance was significantly reduced in the experimental group compared with the physiotherapy without biofeedback group (experimental group-physiotherapy without biofeedback group: -1.6±1.5mm; P=.003). No significant between-group differences were found in the other outcomes.

CONCLUSIONS

Gamepad-based training was feasible and superior to physiotherapy without feedback in improving BBS performance and retaining it for 1 month. After training, 10MWT data were comparable between groups. Further development of the system is warranted to allow the autonomous use of Gamepad outside clinical settings, to enhance gait improvements, and to increase transfer of training effects to real-life contexts.

Comparison of upright balance in stroke, Parkinson and multiple sclerosis

OBJECTIVE

Multiple sclerosis (MS), Parkinson's disease (PD) and stroke (ST) subjects show balance impairments due to damage of the balance control system. The objective of the study was to assess the impact of MS, PD and ST on upright posture in eyes open condition and when visual and/or proprioceptive inputs are altered.

MATERIALS AND METHODS

A total of 188 subjects with MS (n = 80), PD (n = 58) and ST (n = 50), mean age (SD), 57.9 (14.6) years, and 32 healthy subjects (HS) aged 53.7 (15.7) years were assessed by a stabilometric platform in a cross-sectional study.

RESULTS

Compared to HS, MS showed large deviations from normal performances with respect to magnitude (P < 0.001) and regularity (P < 0.05) of body sway irrespective of the altered sensory information. Similarly to MS, PD showed large and abnormal levels of body sway (P < 0.001) and postural tremor (P < 0.05), while ST was the least impaired except for an asymmetrical distribution of body weight between legs (P < 0.001). Finally, the MS group compared to PD and ST showed the largest body instability after eye closure (P < 0.05) and when visual and proprioceptive inputs were removed (P < 0.05). PD showed instability mainly after the alteration of proprioceptive inputs (P < 0.05), while ST showed the smallest increase of body instability when sensory inputs were reduced.

DISCUSSION

Objective assessment revealed pathology-specific balance disorders and showed the differential impact of MS, PD and ST on the ability to use sensory information for balance control.

Hilbert-Huang transform based instrumental assessment of intention tremor in multiple sclerosis

OBJECTIVE

This paper describes a method to extract upper limb intention tremor from gyroscope data, through the Hilbert-Huang transform (HHT), a technique suitable for the study of nonlinear and non-stationary processes. The aims of the study were to: (i) evaluate the method's ability to discriminate between healthy controls and MS subjects; (ii) validate the proposed procedure against clinical tremor scores assigned using Fahn's tremor rating scale (FTRS); and (iii) compare the performance of the HHT-based method with that of linear band-pass filters.

APPROACH

HHT was applied on gyroscope data collected on 20 MS subjects and 13 healthy controls (CO) during finger-to-nose tests (FNTs) instrumented with an inertial sensor placed on the hand. The results were compared to those obtained after traditional linear filtering. The tremor amplitude was quantified with instrumental indexes (TIs) and clinical FTRS ratings.

MAIN RESULTS

The TIs computed after HHT-based filtering discriminated between CO and MS subjects with clinically-detected intention tremor (MS_T). In particular, TIs were significantly higher in the final part of the movement (TI2) with respect to the first part (TI1), and, for all components (X, Y, Z), MS_T showed a TI2 significantly higher than in CO subjects. Moreover, the HHT detected subtle alterations not visible from clinical ratings, as TI2 (Z-component) was significantly increased in MS subjects without clinically-detected tremor (MS_NT). The method's validity was demonstrated by significant correlations between clinical FTRS scores and TI2 related to X (rs = 0.587, p = 0.006) and Y (rs = 0.682, p < 0.001) components. Contrarily, fewer differences among the groups and no correlation between instrumental and clinical indexes emerged after traditional filtering.

SIGNIFICANCE

The present results supported the use of the HHT-based procedure for a fully-automated quantitative and objective measure of intention tremor in MS, which can overcome the limitations of clinical scales and provide supplementary information about this sign.

A new instrumented method for the evaluation of gait initiation and step climbing based on inertial sensors: a pilot application in Parkinson's disease

Background

Step climbing is a demanding task required for personal autonomy in daily living. Anticipatory Postural Adjustments (APAs) preceding gait initiation have been widely investigated revealing to be hypometric in Parkinson’s disease (PD) with consequences in movement initiation. However, only few studies focused on APAs prior to step climbing. In this work, a novel method based on wearable inertial sensors for the analysis of APAs preceding gait initiation and step climbing was developed to further understand dynamic balance control. Validity and sensitivity of the method have been evaluated.

Methods

Eleven PD and 20 healthy subjects were asked to perform two transitional tasks from quiet standing to level walking, and to step climbing respectively. All the participants wore two inertial sensors, placed on the trunk (L2-L4) and laterally on the shank. In addition, a validation group composed of healthy subjects and 5 PD patients performed the tasks on two force platforms. Correlation between parameters from wearable sensors and force platforms was evaluated. Temporal parameters and trunk acceleration from PD and healthy subjects were analyzed.

Results

Significant correlation was found for the validation group between temporal parameters extracted from wearable sensors and force platforms and between medio-lateral component of trunk acceleration and correspondent COP displacement. These results support the validity of the method for evaluating APAs prior to both gait initiation and step climbing. Comparison between PD subjects and a subgroup of healthy controls confirms a reduction in PD of the medio-lateral acceleration of the trunk during the imbalance phase in the gait initiation task and shows similar trends during the imbalance and unloading phase of the step climbing task. Interestingly, PD subjects presented difficulties in adapting the medio-lateral amplitude of the imbalance phase to the specific task needs.

Conclusions

Validity of the method was confirmed by the significant correlation between parameters extracted from wearable sensors and force platforms. Sensitivity was proved by the capability to discriminate PD subjects from healthy controls. Our findings support the applicability of the method to subjects of different age. This method could be a possible valid instrument for a better understanding of feed-forward anticipatory strategies.

Quantitative assessment of upper limb motor function in Multiple Sclerosis using an instrumented Action Research Arm Test

BACKGROUND

Arm impairment in Multiple Sclerosis (MS) is commonly assessed with clinical scales, such as Action Research Arm Test (ARAT) which evaluates the ability to handle and transport smaller and larger objects. ARAT provides a complete upper limb assessment, as it considers both proximal arm and hand, but suffers from subjectivity and poor sensitivity to mild impairment. In this study an instrumented ARAT is proposed to overcome these limitations and supplement the assessment of arm function in MS.

METHODS

ARAT was executed by 12 healthy volunteers and 21 MS subjects wearing a single inertial sensor on the wrist. Accelerometers and gyroscopes signals were used to calculate the duration of each task and its sub-phases (reaching, manipulation, transport, release and return). A jerk index was computed to quantify movement smoothness. For each parameter, z-scores were calculated to analyze the deviation from normative data. MS subjects were clinically assessed with ARAT score, Nine-Hole Peg test (9HPT) and Fahn Tremor Rating Scale (FTRS).

RESULTS

ARAT tasks executed by MS patients were significantly slower (duration increase: 70%) and less smooth (jerk increase: 16%) with respect to controls. These anomalies were mainly related to manipulation, transport and release sub-movements, with the former showing the greatest alterations. A statistically significant decrease in movement velocity and smoothness was also noticed in patients with normal ARAT score. Z-scores related to duration and jerk were strongly correlated with ARAT rating (r < -0.80, p < 0.001) and 9HPT (r < -0.75, p < 0.001) and were significantly different among MS sub-groups with different levels of arm impairments (p < 0.001). Moreover, Z-score related to manipulation-phase jerk was significantly correlated with the FTRS rating of intention tremor (r = 0.84, p < 0.001).

CONCLUSIONS

The present study showed that the proposed method is able to discriminate between control and MS groups and to reveal subtle arm alterations not detectable from ARAT score. Validity was shown by high correlations between instrumental variables and clinical ratings. These results suggested that instrumented ARAT could be a valid quick and easy-to-use method for a sensitive quantification of arm function in MS. Inclusion of finger-mounted sensors could complement present findings and provide further indications about hand function in MS.

A tailored exercise of manipulation of virtual tools to treat upper limb impairment in Multiple Sclerosis

We developed a robot-assisted rehabilitation protocol, specifically designed to treat cerebellar and motor symptoms in subjects with Multiple Sclerosis. The task consists of controlling a `virtual' tool (a mass-spring system), under the effect of a resistive force. The exercise is designed in such a way that task difficulty and the degree of resistance are automatically adjusted to the individual patients' impairment. The protocol included a total of eight 40 min training sessions (2 sessions/week), and automatic regulation of difficulty and resistance was repeated at the beginning of each session. Preliminary results suggest that subjects improve their performance, both within and between sessions. Moreover, task difficulty and resistance tend to increase across sessions, indicating that subjects gradually improve their ability to deal with more challenging versions of the task.

Multi-finger coordination in healthy subjects and stroke patients: a mathematical modelling approach

Background

Approximately 60% of stroke survivors experience hand dysfunction limiting execution of daily activities. Several methods have been proposed to objectively quantify fingers' joints range of motion (ROM), while few studies exist about multi-finger coordination during hand movements. The present work analysed this aspect, by providing a complete characterization of spatial and temporal aspects of hand movement, through the mathematical modelling of multi-joint finger motion in healthy subjects and stroke patients.

Methods

Hand opening and closing movements were examined in 12 healthy volunteers and 14 hemiplegic stroke survivors by means of optoelectronic kinematic analysis. The flexion/extension angles of metacarpophalangeal (MCPJ) and proximal interphalangeal joints (IPJ) of all fingers were computed and mathematically characterized by a four-parameter hyperbolic tangent function. Accuracy of the selected model was analysed by means of coefficient of determination (R²) and root mean square error (RMSE). Test-retest reliability was quantified by intraclass correlation coefficient (ICC) and test-retest errors. Comparison between performances of healthy controls and stroke subjects were performed by analysing possible differences in parameters describing angular and temporal aspects of hand kinematics and inter-joint, inter-digit coordination.

Results

The angular profiles of hand opening and closing were accurately characterized by the selected model, both in healthy controls and in stroke subjects (R² > 0.973, RMSE < 2.0°). Test-retest reliability was found to be excellent, with ICC > 0.75 and remarking errors comparable to those obtained with other methods. Comparison with healthy controls revealed that hemiparetic hand movement was impaired not only in joints ROM but also in the temporal aspects of motion: peak velocities were significantly decreased, inter-digit coordination was reduced of more than 50% and inter-joint coordination patterns were highly disrupted. In particular, the stereotypical proximal-to-distal opening sequence (reversed during hand closing) found in healthy subjects, was altered in stroke subjects who showed abnormally high delay between IPJ and MCPJ movement or reversed moving sequences.

Conclusions

The proposed method has proven to be a promising tool for a complete objective characterization of spatial and temporal aspects of hand movement in stroke, providing further information for a more targeted planning of the rehabilitation treatment to each specific patient and for a quantitative assessment of therapy's outcome.

Effect of L-dopa and subthalamic nucleus stimulation on arm and leg swing during gait in Parkinson's Disease

The effects of subthalamic nucleus (STN) stimulation and L-dopa administration on the arm and leg swing movements associated with overground walking were studied in a group of patients with idiopathic Parkinson's disease (PD). Ten patients undergoing deep brain stimulation and twenty controls were tested using 3D kinematic motion analysis. Parkinsonian patients under basal conditions walked more slowly and with reduced arm and leg swing compared to controls. Moreover, they displayed significant impairments of the normal interlimb coordination. Both STN stimulation and L-dopa increased the walking speed and the amplitude of arm and leg swing movements. Additional improvements of the coordination between upper and lower limb were documented by reductions of the phase-shift between arm and ipsilateral leg motion, with displacement toward the control range (perfect counterphase). STN stimulation alone and L-dopa alone produced similar effects on the variables analyzed. The combination of the two treatments, instead, yielded additive effects on the gait speed and a slight increase of the upper and lower limb range of motion, in the absence of further improvements in the inter-segmental coordination. Moreover, whereas the increased arm swing could be accounted by the sole adoption of a higher gait speed, both the increment of the leg movement amplitude and the decreased interlimb phase shift appeared to imply an additional effect, possibly related to the treatment. These results may suggest that differential supraspinal controls operate on the neural networks subserving upper and lower limb motion during human walking.

The association between impaired turning and normal straight walking in Parkinson's disease

Turning whilst walking was investigated by gait analysis in a group of Parkinson's Disease (PD) patients with mild clinical impairment and no significant abnormalities in stride parameters and kinematics of steady-state, linear walking. Comparison with age-matched controls demonstrated that patients approached turns with a slower step and completed turning with a greater number of steps. Moreover, the normal cranio-caudal sequence, whereby rotation of the head toward the intended direction of travel is followed by rotation of the trunk, was replaced by nearly simultaneous rotation of head and trunk and decreased relative head excursion after the second turning step. The evidence of abnormal inter-segmental coordination during turning in mildly affected, normally walking patients suggests that task-specific pathophysiological mechanisms, not necessary related to basic locomotor deficits, underlie disturbed directional changes in PD. Furthermore, turning-related neural systems may be more vulnerable to functional impairments associated with PD, as compared with linear walking. Hierarchically higher control levels involved in the turning ability may explain the observed unexpected association.

Unilateral and Bilateral Subthalamic Nucleus Stimulation in Parkinson's Disease: Effects on EMG Signals of Lower Limb Muscles During Walking

The effects of subthalamic nucleus (STN) stimulation on the spatio-temporal organization of locomotor commands directed to lower limb muscles were studied in subjects with idiopathic Parkinson's Disease (PD) by recording the EMG activity produced during steady-state walking in representative thigh (rectus femoris, RF, and semimembranosus, SM) and leg (gatrocnemius medialis, GAM, and tibialis anterior, TA) muscles, under four experimental conditions: basal stimulation OFF, unilateral (right and left) stimulation ON, and bilateral stimulation ON. Locomotor profiles of all of the muscles tested were found to be substantially affected by STN stimulation, either in terms of restoration/enhancement of the main activity bursts or normalization of recruitment timing thereof. Responses showed relatively higher statistical significance in the distal groups (GAM and TA) and, within them, for the EMG components called into action over the ground-contact (ankle dorsiflexors) and midstance (ankle plantarflexors) phases of the stride cycle. In line with data obtained from clinical rating, unilateral stimulation produced less consistent EMG changes compared with bilateral stimulation. However, at variance with clinical effects, which prevailed on the side of the body contralateral to stimulation, EMG responses to unilateral stimulation were usually symmetrical. Results indicate that the impact of STN stimulation on locomotor activation of lower limb muscles in PD is characterized by: 1) substantial effects exhibiting differential topographical (distal versus proximal) and stride-phase (stance versus swing) consistency and 2) absence of the lateralized actions typically observed for the clinical signs of the disease. Interaction with the activity of functionally different executive systems might account for the observed pattern of responsiveness.