Virtual reality-enhanced walking in people post-stroke: effect of optic flow speed and level of immersion on the gait biomechanics.

BACKGROUND: Optic flow-the apparent visual motion experienced while moving-is absent during treadmill walking. With virtual reality (VR), optic flow can be controlled to mediate alterations in human walking. The aim of this study was to investigate (1) the effects of fully immersive VR and optic flow speed manipulation on gait biomechanics, simulator sickness, and enjoyment in people post-stroke and healthy people, and (2) the effects of the level of immersion on optic flow speed and sense of presence. METHODS: Sixteen people post-stroke and 16 healthy controls performed two VR-enhanced treadmill walking sessions: the semi-immersive GRAIL session and fully immersive head-mounted display (HMD) session. Both consisted of five walking trials. After two habituation trials (without and with VR), participants walked three more trials under the following conditions: matched, slow, and fast optic flow. Primary outcome measures were spatiotemporal parameters and lower limb kinematics. Secondary outcomes (simulator sickness, enjoyment, and sense of presence) were assessed with the Simulator Sickness Questionnaire, Visual Analogue Scales, and Igroup Presence Questionnaire. RESULTS: When walking with the immersive HMD, the stroke group walked with a significantly slower cadence (-3.69strides/min, p = 0.006), longer stride time (+ 0.10 s, p = 0.017) and stance time for the unaffected leg (+ 1.47%, p = 0.001) and reduced swing time for the unaffected leg (- 1.47%, p = 0.001). Both groups responded to the optic flow speed manipulation such that people accelerated with a slow optic flow and decelerated with a fast optic flow. Compared to the semi-immersive GRAIL session, manipulating the optic flow speed with the fully immersive HMD had a greater effect on gait biomechanics whilst also eliciting a higher sense of presence. CONCLUSION: Adding fully immersive VR while walking on a self-paced treadmill led to a more cautious gait pattern in people post-stroke. However, walking with the HMD was well tolerated and enjoyable. People post-stroke altered their gait parameters when optic flow speed was manipulated and showed greater alterations with the fully-immersive HMD. Further work is needed to determine the most effective type of optic flow speed manipulation as well as which other principles need to be implemented to positively influence the gait pattern of people post-stroke. TRIAL REGISTRATION NUMBER: The study was pre-registered at ClinicalTrials.gov (NCT04521829).

Proportion of falls reported in persons with Parkinson's disease: A meta-analysis.

OBJECTIVE: Falls can be highly debilitating and have an important negative impact on the quality of life of patients with Parkinson's disease (PD). The aim of this systematic review and meta-analysis is to provide an up-to-date overview of the prevalence of ≥1 fall and ≥2 falls in idiopathic PD. DATA SOURCES: MEDLINE, Web of Science, Embase and Cinahl databases were systematically searched until 04 July 2022 for prospective studies reporting fall prevalence in persons with idiopathic PD. METHODS: Pooled prevalence rates with 95% confidence intervals (CIs) were computed using random-effects models. Heterogeneity among studies was assessed using the I2 statistic. RESULTS: A total of 54 studies (7546 participants) were included, and random-effects meta-analysis yielded a pooled proportional fall rate of 0.48 (95% CI [0.43-0.52], I2 = 93%, 46 studies, 6874 participants) for classification 1 (≥1 fall) and a pooled proportional fall rate of 0.32 (95% CI [0.27-0.37], I2 = 78%, 31 studies, 5672 participants) for classification 2 (≥2 falls). Subgroup analysis on the classification of falls, and length and method of monitoring falls did not reveal significant differences and did not reduce between-study variability. CONCLUSION: Pooled estimates suggest that one in two persons with PD fall at least once, and one in three fall at least twice within the registered time period. Substantial variability remains after pooling fall prevalence rates according to the length and method of monitoring. Therefore, no recommendations can be made concerning these methodological aspects. Future research on falls in PD is encouraged to implement best practice recommendations to monitor and report fall data.

Effects of Oral Levodopa on Balance in People with Idiopathic Parkinson's Disease.

BACKGROUND: Balance impairment is a frequent cause of morbidity and mortality in people with Parkinson's disease (PD). As opposed to the effects of appendicular motor symptoms, the effects of Levodopa on balance impairment in idiopathic PD are less clear. OBJECTIVE: To review the literature on the effects of oral Levodopa on clinical balance test performance, posturography, step initiation, and responses to perturbation in people with idiopathic PD (PwPD). METHODS: A systematic search of three scientific databases (Pubmed, Embase, and Web of Science) was conducted in accordance with PRISMA guidelines. For the pilot meta-analysis, standardized mean differences with 95% confidence intervals were calculated using an inverse variance random effects model. Data not suitable for implementation in the meta-analysis (missing means or standard deviations, and non-independent outcomes) were analyzed narratively. RESULTS: A total of 2772 unique studies were retrieved, of which 18 met the eligibility criteria and were analyzed, including data of 710 idiopathic PwPD. Levodopa had a significant positive effect on the Berg Balance Scale, the Push and Release test, and jerk and frequency parameters during posturography. In contrast, some significant negative effects on velocity-based sway parameters were found during posturography and step initiation. However, Levodopa had no significant effect on most step initiation- and all perturbation parameters. CONCLUSION: The effects of Levodopa on balance in PwPD vary depending on the outcome parameters and patient inclusion criteria. A systematic approach with well-defined outcome parameters, and prespecified, sensitive and reliable tests is needed in future studies to unravel the effects of oral Levodopa on balance.

Skeletal Muscle Changes in the First Three Months of Stroke Recovery: A Systematic Review.

BACKGROUND: Rehabilitation is important in the first months after a stroke for recovery of functional ability, but it is also challenging, since distinct recovery trajectories are seen. Therefore, studying the early changes in muscle characteristics over time (e.g. muscle strength, muscle mass and muscle volume), which are known to be associated with functional abilities, may deepen our understanding of underlying recovery mechanisms of stroke survivors. OBJECTIVE: This systematic review aims to describe the longitudinal changes in skeletal muscles, including muscle strength, muscle mass and muscle volume, during the first 3 months post-stroke. METHODS: Electronic searches were conducted in Medline, Scopus and CENTRAL. Longitudinal cohort studies or controlled interventional trials that report data about patients in the first 3 months after stroke were identified. Skeletal muscle characteristics should be measured at least twice within 3 months post-stroke by objective, quantitative assessment methods (e.g. dynamometry, ultrasound, computed tomography). Effect sizes were calculated as Hedges' g using standardized mean differences. RESULTS: A total of 38 studies (1,097 subjects) were found eligible. Results revealed an mean increase on the paretic side for upper and lower limb muscle strength (small to moderate effect sizes), whereas muscle thickness decreased (moderate to large effect sizes). Similar, but smaller, effects were found on the non-paretic side. There were insufficient data available to draw conclusions about lean muscle mass and muscle cross-sectional area. No studies aimed at investigating distinct trajectories of the muscle changes. CONCLUSION: Muscle strength and thickness changes during the first 3 months after stroke in both the paretic and non-paretic side. Future studies should aim to understand "how" the stroke-induced muscle strength changes are achieved. Exploring existing data from longitudinal studies, by using cluster analyses, such as pattern recognition, could add to the current knowledge-base.

Physiological responses and perceived exertion during robot-assisted treadmill walking in non-ambulatory stroke survivors.

PURPOSE: To examine physiological responses and perceived exertion during robot-assisted treadmill walking in non-ambulatory stroke survivors; compare these outcomes with aerobic exercise recommendations; and investigate the effect of robotic assistance. MATERIALS AND METHODS: Twelve non-ambulatory stroke survivors (67 ± 11 years-old, 84 ± 38 d post-stroke) participated. Subjects walked three times 20 min (1 session/day) in the Lokomat: once with conventional exercise parameters, once with 60% robotic assistance and once with 100% robotic assistance. Gas exchange and heart rate were monitored continuously. Perceived exertion was assessed every 3 min during walking. RESULTS: During conventional robot-assisted treadmill walking, net perceived exertion (0-14 scale) significantly increased between minute 6 (median = 2, interquartile range = 4) and 18 (median = 5, interquartile range = 4). Net physiological responses did not significantly change over time. Throughout exercise, percentage of predicted heart rate reserve was significantly below the 40% threshold (medians: 11-14%) and percentage of predicted maximum heart rate reached the 55% threshold (medians: 59-60%). Perceived exertion reached the 11-point threshold halfway. Net physiological responses and perceived exertion did not significantly differ between 60% and 100% robotic assistance. CONCLUSIONS: The assistance level that non-ambulatory stroke survivors require at their highest tolerable walking speed seems too high to sufficiently stress the cardiorespiratory system during robot-assisted treadmill walking.Implications for rehabilitationThe exercise intensity of 20-minute conventional robot-assisted treadmill walking can be low, and might be too low to challenge the cardiorespiratory system of non-ambulatory stroke survivors.Lowering the level of robotic assistance from 100% to 60% does not seem to increase the exercise intensity of 20-minute robot-assisted treadmill walking.

Muscle changes after stroke and their impact on recovery: time for a paradigm shift? Review and commentary.

In stroke rehabilitation there is a growing body of evidence that not all patients have the same potential to recover. Understanding the processes that give rise to the heterogeneous treatment responses in stroke survivors will lay foundations for any conceivable advance in future rehabilitation interventions. This review was set out to shine new light on the debate of biomarkers in stroke rehabilitation by linking fundamental insights from biogerontological sciences to neurorehabilitation sciences. In particular, skeletal muscle changes and inflammation are addressed as two potential constructs from which biomarkers for stroke rehabilitation can be derived. Understanding the interplay between these constructs as well as their relation to recovery could enhance stroke rehabilitation in the future. The rationale for the selection of these constructs is three-fold: first, recent stroke literature emphasizes the importance of identifying muscle wasting (also called stroke-induced muscle wasting) in stroke patients, a concept that is widely investigated in geriatrics but less in the stroke population. Second, insights from transdisciplinary research domains such as gerontology have shown that inflammation has severe catabolic effects on muscles, which may impede rehabilitation outcomes such as gait recovery. Last, it has been proven that (high-intensity) muscle strengthening exercises have strong anti-inflammatory effects in a non-stroke population. Therefore, an evidence-based rationale is presented for developing research on individual changes of muscle and inflammation after a stroke.

The use of shoulder orthoses post-stroke: effects on balance and gait. A systematic review.

INTRODUCTION: Since there is no clear conclusion concerning the use of arm slings in the prevention or reduction of shoulder subluxation or shoulder pain in stroke patients, it seems important to explore other potentially beneficial effects. Earlier research already suggested that the upper limb might play a considerable role in efficient balance and gait in stroke patients. Therefore, the aim of this systematic review was to investigate the effects of wearing an arm sling on balance and/or gait in stroke patients. This information could support the decision-making concerning the use of shoulder orthoses after stroke. EVIDENCE ACQUISITION: Four electronic databases (Pubmed/MEDLINE, Embase, Web of Science and CINAHL/EBSCO) were searched until April 8th, 2019. Search alerts were set and followed until January 2020 to assure no new eligible articles were published. Reference lists of included studies were hand searched. All studies examining the effect of wearing an upper limb orthosis on balance and gait in stroke patients were included. Two reviewers independently identified eligible studies and extracted data. The methodological quality of included trials was assessed using the QualSyst assessment tool for quantitative studies. Prospero registration number: CRD42019130282. EVIDENCE SYNTHESIS: Ten studies, examining 283 stroke patients with moderate to low level of upper limb impairment, were included in the quantitative synthesis of the results. The pooled mean time since stroke was 21.88±9.03 months. Only minor effects on balance or gait related outcome parameters could be detected in favor of wearing an arm sling. However, these changes did not exceed the minimal clinical important difference (MCID). CONCLUSIONS: So far no strong evidence is available regarding a potential benefit of wearing an arm sling on balance and gait for stroke patients. However, further research with longer intervention periods, can be useful to determine if stroke patients in the early phases after stroke or with persistent UL paresis might possibly benefit from wearing an arm sling.

Energy consumption and cost during walking with different modalities of assistance after stroke: a systematic review and meta-analysis.

Purpose: To estimate pooled rates of gross and net energy consumption (ml/kg/min and J/kg/min) and energy cost (ml/kg/m and J/kg/m) during level surface walking with different assistance modalities post-stroke.Materials and Methods: Four databases were searched using keywords related to stroke, walking, and energy requirements. Three independent reviewers screened 3296 records and included 42 studies in quantitative analysis.Results: Pooled rates without significant important heterogeneity were identified for: gross energy consumption during unassisted overground walking at comfortable walking speed (10.55 ml/kg/min; 95% CI [9.93-11.16]), gross energy consumption during treadmill walking with rigid exoskeleton assistance (7.08 ml/kg/min; 95% CI [6.52-7.65]), gross energy cost during unassisted overground walking in patients with chronic stroke (0.24 ml/kg/m; 95% CI [0.28-0.48]), gross energy cost during unassisted treadmill walking in patients with subacute stroke (0.45 ml/kg/m; 95% CI 0.45-0.45]), and net energy cost during overground walking with assistive devices and orthoses in patients with chronic stroke (4.12 J/kg/m, 95% CI [3.55-4.69]).Conclusions: Walking, unassisted and with the use of assistive devices and lower limb orthoses, induces low- to moderate-intensity exercise as recommended by exercise guidelines for stroke survivors. Future studies should explore whether bodyweight-supported or robot-assisted walking can also reach moderate-intensity.Implications for RehabilitationTo induce sufficient cardiorespiratory stress during gait rehabilitation (i.e., moderate-intensity), therapists should train ambulatory patients with stroke without any assistance or if needed with the help of assistive devices or lower limb orthoses.For severely impaired patients who cannot walk independently, therapists could use bodyweight support systems, exoskeletons, or end-effectors to induce low-intensity aerobic exercise.

The Effect of Optic Flow Speed on Active Participation During Robot-Assisted Treadmill Walking in Healthy Adults.

This study aimed to investigate: 1) the effect of optic flow speed manipulation on active participation during robot-assisted treadmill walking (RATW), 2) the influence of the type of virtual environment, and 3) the level of motion sickness and enjoyment. Twenty-eight healthy older adults were randomized in two groups: "stimulus rich" Park group (50% male, 61± 6 year) and "stimulus poor" Hallway group (43% male, 62± 5 year). Subjects walked in the Lokomat with immersive virtual reality (VR) with a matched, slow and fast optic flow speed, each lasting 7 minutes. Active participation was measured by continuously assessing the human-machine interaction torques at the hip and knee joints and muscle activity of the Vastus Medialis and Biceps Femoris. Motion sickness and enjoyment were assessed with the Simulator Sickness Questionnaire (SSQ) and Physical Activity Enjoyment Scale (PACES) respectively. In both groups optic flow speed manipulation in both directions led to a decrease in bilateral hip interaction torques towards flexion at the end of the stance phase compared to matched speed. In the Hallway group, walking with slow optic flow elicited 32% more muscle activity of the Vastus Medialis. There were no significant differences between both groups for the SSQ and PACES. Optic flow speed manipulation appears to have only a small effect on the active participation of healthy people during RATW. The type of virtual environment did not affect their activity, motion sickness or enjoyment. However, the addition of immersive VR during RATW was well tolerated and enjoyable. Further research with patients is necessary.

Validity and Reproducibility of Inertial Physilog Sensors for Spatiotemporal Gait Analysis in Patients With Stroke.

Spatiotemporal gait analysis can provide quantitative information to assess treatment outcomes in stroke survivors. Therefore, clinicians need a portable, easy-to-use and low-cost tool that accurately and reliably measures spatiotemporal gait parameters. This paper examined the concurrent validity and reproducibility of the Gait Up gait analysis package for the spatiotemporal gait analysis in subacute stroke survivors. Twenty-five subacute stroke survivors participated in two walking tests. Spatiotemporal gait parameters were synchronously measured by 2 foot-worn inertial sensors (Physilog) and three-dimensional motion capturing (Vicon). Intraclass correlation coefficients, standard errors of measurement, smallest detectable changes, limits of agreement, and the Bland-Altman plots were calculated for the paretic and non-paretic side. After removing a consistent outlier (i.e., data of the paretic side of subject 36 who dragged his foot), agreement between both devices was good to excellent for paretic and non-paretic gait cycle time, cadence, stride length, stride velocity, and double support and moderate for paretic and non-paretic stance and swing. The Bland-Altman plots supported these findings. Test-retest reliability was good to excellent for most parameters, except paretic stance and swing. In conclusion, the Gait Up gait analysis package is a valid and reliable tool to measure paretic and non-paretic gait cycle time, cadence, stride length, and stride velocity in subacute patients with stroke, who do not exhibit severe dragging of the paretic foot. However, the algorithm should be improved for the analysis of paretic stance and swing phase.

Virtual reality during gait training: does it improve gait function in persons with central nervous system movement disorders? A systematic review and meta-analysis.

BACKGROUND: During gait training in persons with central nervous system (CNS) movement disorders, virtual reality (VR) can offer added value by providing task-specific gait training in more interactive and motivating environments. OBJECTIVE: To summarize current evidence for the effectiveness of VR-enhanced gait training in persons with CNS movement disorders. METHODS: PubMed, Web of Science and CENTRAL were systematically searched for studies using VR during walking to improve gait outcomes (spatiotemporal, functional, kinematic and kinetic). Meta-analyses were performed to estimate pooled effects. RESULTS: Eighteen studies with in total 337 patients were included (12 studies with people post-stroke, 4 with multiple sclerosis, 1 with Parkinson's disease, 1 with traumatic brain injury). Spatiotemporal and functional parameters significantly improved in each population after the VR training. Compared to gait training without VR, differences in favor of VR were found for spatiotemporal and functional parameters only in people post-stroke. CONCLUSION: VR-enhanced gait training is an effective method to improve spatiotemporal and functional parameters in persons with CNS movement disorders. Current evidence supports that, in comparison to training without VR, for people post-stroke VR-enhanced gait training is more effective to improve gait function. Future research regarding other outcome measures and other CNS movement disorders is necessary.

Physiological Responses and Perceived Exertion During Robot-Assisted and Body Weight-Supported Gait After Stroke.

INTRODUCTION: Physiological responses are rarely considered during walking after stroke and if considered, only during a short period (3-6 minutes). The aims of this study were to examine physiological responses during 30-minute robot-assisted and body weight-supported treadmill and overground walking and compare intensities with exercise guidelines. METHODS: A total of 14 ambulatory stroke survivors (age: 61 ± 9 years; time after stroke: 2.8 ± 2.8 months) participated in 3 separate randomized walking trials. Patients walked overground, on a treadmill, and in the Lokomat (60% robotic guidance) for 30 minutes at matched speeds (2.0 ± 0.5 km/h) and matched levels of body weight support (BWS; 41% ± 16%). Breath-by-breath gas analysis, heart rate, and perceived exertion were assessed continuously. RESULTS: Net oxygen consumption, net carbon dioxide production, net heart rate, and net minute ventilation were about half as high during robot-assisted gait as during body weight-supported treadmill and overground walking ( P < .05). Net minute ventilation, net breathing frequency, and net perceived exertion significantly increased between 6 and 30 minutes (respectively, 1.8 L/min, 2 breaths/min, and 3.8 units). During Lokomat walking, exercise intensity was significantly below exercise recommendations; during body weight-supported overground and treadmill walking, minimum thresholds were reached (except for percentage of heart rate reserve during treadmill walking). CONCLUSION: In ambulatory stroke survivors, the oxygen and cardiorespiratory demand during robot-assisted gait at constant workload are considerably lower than during overground and treadmill walking at matched speeds and levels of body weight support. Future studies should examine how robotic devices can be Future studies should examine how robotic devices can be exploited to induce aerobic exercise.

Male and female opinions about orthotic devices of the lower limb: A multicentre, observational study in patients with central neurological movement disorders.

BACKGROUND AND OBJECTIVE: Because user-satisfaction and acceptance may partly determine the grade of compliance to an orthotic device (OD), the aim of this multicentre observational study was to inquire the reasons for acceptance and the user-satisfaction of an OD of the lower limb in male and female central neurological movement disorders (CNMD) patients. METHODS: Persons with CNMD having at least one prescribed OD of the lower limb were included. Two questionnaires were used: the MIRAD-ACCORT-II (reasons for acceptance) and a modified version of the D-QUEST 2.0 (user-satisfaction). Descriptive analyses were performed and to analyse the differences between the males' and females' answers Chi2- and Mann-Whitney U tests were used. RESULTS: Twenty-six stroke and 23 multiple sclerosis patients participated (53% males). "Comfort", "safety", "effectiveness" and "ease of use" were reported as most important aspects. 86% of the patients were (very) satisfied about their OD. Only for the aspect safety, compared to males, significant more females reported that if the OD is not safe enough they will not use it. CONCLUSION: For both, males and females, aspects related to comfort and functionality were reported as much more important than the esthetical aspects, and in general they are quite satisfied with the OD and the process of providing the OD. Orthopaedic technicians and health care providers can take these aspects into account when developing, constructing and providing OD's.

What is the opinion of patients with multiple sclerosis and their healthcare professionals about lower limb orthoses? A qualitative study using focus group discussions.

OBJECTIVE: The aim of this study was to collect patients' and healthcare professionals' opinions about lower limb orthoses (LL-orthoses): 1) the positive and negative aspects; 2) the differences in wearing them according to location; and 3) their recommendations for future modifications. METHODS: Four focus group discussions were performed, with in total twenty patients with MS with a prescribed LL-orthosis and seven healthcare professionals. Audiotaped discussions were transcribed and qualitatively processed (NVivo11). RESULTS: Healthcare professionals and patients state that a LL-orthosis improves gait and reduces the risk of falling. Some negative aspects were indicated like stigmatization, difficulties to put on and off the LL-orthosis and the aesthetic aspects. Several patients mentioned that they did not get enough or no correct information about the adaptability and use of the orthoses. Opinions regarding differences in wearing according to location (e.g. in and outside the rehabilitation center) were diverse. Recommendations for future changes were e.g. more refined and firmer orthoses. CONCLUSIONS: The opinions collected are interesting for taking into account in the process of construction and delivering of LL-orthoses. Future research should focus on the opinions concerning different types of LL-orthosis in relation with the severity of the limitations of the patients.

Effect of Transcutaneous Electric Nerve Stimulation on Pain after Total Knee Arthroplasty: A Blind Randomized Controlled Trial.

Transcutaneous electric nerve stimulation (TENS) has proven to be effective for postsurgical pain relief. However, there is a lack of well-constructed clinical trials investigating the effect of TENS after total knee arthroplasty (TKA). In addition, previous investigations reported that low- and high-frequency TENSs produced analgesic tolerance after 4 or 5 days of treatment. The aim of this study is to explore the effect of burst TENS on pain during hospitalization after TKA and to investigate whether burst TENS produces analgesic tolerance after 4 or 5 days of treatment. This stratified, triple blind, randomized controlled trial was approved by the University Hospital Brussels. Sixty-eight subjects were screened for eligibility before surgery; 54 were found eligible and 53 were included in the analyses. Patients were allocated to either a burst TENS or sham burst TENS group. TENS was applied daily during continuous passive mobilization. Knee pain intensity, knee range of motion, and analgesic consumption were assessed daily. Patients received burst TENS (N = 25) or sham burst TENS (N = 28). No significant differences in knee pain intensity were found between the groups (p > 0.05). Within the TENS and the sham TENS groups, the difference in knee pain before and after treatment did not evolve over time (p > 0.05). This study found no effects of burst TENS compared with sham burst TENS on pain during hospitalization after TKA.

Metabolic Effects Induced by a Kinematically Compatible Hip Exoskeleton During STS.

OBJECTIVE: Show the benefit of kinematically compatible joint structures in exoskeletons for improving their performance in reducing metabolic consumption. METHODS: Subjects were fitted with a hip exoskeleton, with misalignment compensation for all degrees of freedom and were instructed to perform recurring sit-to-stand motions for 5 min. This was executed three times: Unequipped (i.e., not wearing the exoskeleton), assisted, and unassisted. During each trial, oxygen consumption and muscle activity were monitored. RESULTS: An increased oxygen consumption was observed between the unequipped and the unassisted trial. During the assisted trial, oxygen consumption was reduced to levels seen in the unequipped state. Muscle activity increased for rectus femoris and tibialis anterior and decreased for biceps femoris and gluteus maximus. CONCLUSION: Oxygen consumption only increases in accordance with the added mass. No added penalty was seen related to increased inertia or hindrance of natural motion patterns. This indicates that the mechanism operates as intended. The increased muscle activity can be explained by the nature of the actuation system, which is not optimized for sit-to-stand tasks. A more targeted actuation system can easily reduce muscle activity, and therefore, induce a reduced oxygen consumption, below unequipped levels. SIGNIFICANCE: Because the benefits induced by using these systems are independent of user capabilities or deficiencies, it is applicable in a wide range of exoskeleton applications. The design presented here, allows for the realization of compact and light devices, that have a minimal impact on the metabolic cost of their user. This allows to maximally exploit the metabolically beneficial effects of a well-designed actuation system.

Bilateral, Misalignment-Compensating, Full-DOF Hip Exoskeleton: Design and Kinematic Validation.

A shared design goal for most robotic lower limb exoskeletons is to reduce the metabolic cost of locomotion for the user. Despite this, only a limited amount of devices was able to actually reduce user metabolic consumption. Preservation of the natural motion kinematics was defined as an important requirement for a device to be metabolically beneficial. This requires the inclusion of all human degrees of freedom (DOF) in a design, as well as perfect alignment of the rotation axes. As perfect alignment is impossible, compensation for misalignment effects should be provided. A misalignment compensation mechanism for a 3-DOF system is presented in this paper. It is validated by the implementation in a bilateral hip exoskeleton, resulting in a compact and lightweight device that can be donned fast and autonomously, with a minimum of required adaptations. Extensive testing of the prototype has shown that hip range of motion of the user is maintained while wearing the device and this for all three hip DOFs. This allowed the users to maintain their natural motion patterns when they are walking with the novel hip exoskeleton.

Motivation, expectations, and usability of a driven gait orthosis in stroke patients and their therapists.

BACKGROUND: In the development of efficacious driven gait orthoses (DGO), it is an added value to consider patients' and therapists' perspectives concerning robot-assisted gait training (RAGT). A better understanding of these issues may improve the process of care and outcome. OBJECTIVES: This study aimed to examine stroke patients' motivation and expectations of RAGT, and therapists' expectations and perspectives on the usability of RAGT. Additionally, the differences in expectations between stroke patients and their therapists were analyzed. METHODS: A cross sectional, multi-center, three-group trial was conducted. Included were (1) stroke patients who have experience with RAGT (i.e. the stroke user group), (2) stroke patients who have no experience with RAGT (i.e. the stroke non-user group), and (3) therapists who have experience with RAGT (i.e. the therapist user group). The Intrinsic Motivation Inventory (IMI), Credibility/Expectancy Questionnaire (CEQ), and Usefulness, Satisfaction and Ease of Use Questionnaire (USE) were used. Descriptive statistics and non-parametric Kruskal-Wallis tests were conducted. RESULTS: In total, 46 subjects were assessed (stroke user group: n = 23, stroke non-user group: n = 14, therapist user group: n = 9). IMI subscale scores ranged from 42 to 88%. Mean credibility and expectancy ranged from 80 to 85% and 57 to 72%, respectively, with no significant differences between groups. USE subscale scores ranged from 61 to 72%. CONCLUSIONS: Stroke user group patients seem quite motivated to train with the DGO and both patients and therapists reasonably believe that this training could improve gait functioning. Therapists are moderately satisfied with the usability of the DGO, but there is room for improvement with respect to usefulness and ease of use.

The immediate effects of robot-assistance on energy consumption and cardiorespiratory load during walking compared to walking without robot-assistance: a systematic review.

PURPOSE: The integration of sufficient cardiovascular stress into robot-assisted gait (RAG) training could combine the benefits of both RAG and aerobic training. The aim was to summarize literature data on the immediate effects of RAG compared to walking without robot-assistance on metabolic-, cardiorespiratory- and fatigue-related parameters. METHODS: PubMed and Web of Science were searched for eligible articles till February 2016. Means, SDs and significance values were extracted. Effect sizes were calculated. RESULTS: Fourteen studies were included, concerning 155 participants (85 healthy subjects, 39 stroke and 31 spinal cord injury patients), 9 robots (2 end-effectors, 1 treadmill-based and 6 wearable exoskeletons), and 7 outcome parameters (mostly oxygen consumption and heart rate). Overall, metabolic and cardiorespiratory parameters were lower during RAG compared to walking without robot-assistance (moderate to large effect sizes). In healthy subjects, when no body-weight support (BWS) was provided, RAG with an end-effector device was more energy demanding than walking overground (p > .05, large effect sizes). CONCLUSIONS: Generally, results suggest that RAG is less energy-consuming and cardiorespiratory stressful than walking without robot-assistance, but results depend on factors such as robot type, walking speed, BWS and effort. Additional research is needed to draw firm conclusions. Implications for Rehabilitation Awareness of the energy consumption and cardiorespiratory load of robot-assisted gait (RAG) training is important in the rehabilitation of (neurological) patients with impaired cardiorespiratory fitness and patients who are at risk of cardiovascular diseases. On the other hand, the integration of sufficient cardiometabolic stress in RAG training could combine the effects of both RAG and aerobic training. Energy consumption and cardiorespiratory load during walking with robot-assistance seems to depend on factors such as robot type, walking speed, body-weight support or amount of effort. These parameters could be adjusted in RAG rehabilitation to make RAG more or less energy-consuming and cardiorespiratory stressful. Overall, short duration exoskeleton walking seems less energy-consuming and cardiorespiratory stressful than walking without robot-assistance. This might implicate that the exercise intensity is safe for (neurological) patients at risk of cardiovascular diseases. How this changes in extended walking time is unclear.