Towards more effective robotic gait training for stroke rehabilitation: a review

A single-center, assessor-blinded, randomized controlled clinical trial to test the safety and efficacy of a novel brain-computer interface controlled functional electrical stimulation (BCI-FES) intervention for gait rehabilitation in the chronic stroke population

BACKGROUND

In the United States, there are over seven million stroke survivors, with many facing gait impairments due to foot drop. This restricts their community ambulation and hinders functional independence, leading to several long-term health complications. Despite the best available physical therapy, gait function is incompletely recovered, and this occurs mainly during the acute phase post-stroke. Therapeutic options are limited currently. Novel therapies based on neurobiological principles have the potential to lead to long-term functional improvements. The Brain-Computer Interface (BCI) controlled Functional Electrical Stimulation (FES) system is one such strategy. It is based on Hebbian principles and has shown promise in early feasibility studies. The current study describes the BCI-FES clinical trial, which examines the safety and efficacy of this system, compared to conventional physical therapy (PT), to improve gait velocity for those with chronic gait impairment post-stroke. The trial also aims to find other secondary factors that may impact or accompany these improvements and establish the potential of Hebbian-based rehabilitation therapies.

METHODS

This Phase II clinical trial is a two-arm, randomized, controlled, longitudinal study with 66 stroke participants in the chronic (> 6 months) stage of gait impairment. The participants undergo either BCI-FES paired with PT or dose-matched PT sessions (three times weekly for four weeks). The primary outcome is gait velocity (10-meter walk test), and secondary outcomes include gait endurance, range of motion, strength, sensation, quality of life, and neurophysiological biomarkers. These measures are acquired longitudinally.

DISCUSSION

BCI-FES holds promise for gait velocity improvements in stroke patients. This clinical trial will evaluate the safety and efficacy of BCI-FES therapy when compared to dose-matched conventional therapy. The success of this trial will inform the potential utility of a Phase III efficacy trial.

TRIAL REGISTRATION

The trial was registered as "BCI-FES Therapy for Stroke Rehabilitation" on February 19, 2020, at clinicaltrials.gov with the identifier NCT04279067.

Robotic exoskeleton-assisted walking rehabilitation for stroke patients: a bibliometric and visual analysis

Objective

This study aimed to conduct a bibliometric analysis of the literature on exoskeleton robot assisted walking rehabilitation for stroke patients in the Web of Science Core Collection over the past decade.

Method

Retrieved literature on exoskeleton robot assisted gait training for stroke hemiplegic patients from the Web of Science Core Collection from 1 January 2014 to 31 January 2024. The search method was topic search, and the types of documents were "article, meeting abstract, review article, early access." CiteSpace was used to analyze the search results from countries, institutions, keywords, cited references and cited authors.

Result

A total of 1,349 articles were retrieved, and 1,034 were ultimately included for visualization analysis. The annual publication volume showed an upward trend, with countries, institutions, and authors from Europe and America in a leading position. The core literature was also published by authors from European and American countries. The keywords were divided into 8 clusters: # 0 soft robotic exit, # 1 robot assisted gain training, # 2 multiple scales, # 3 magnetic rheological brake, # 4 test retest reliability, # 5 electromechanical assisted training, # 6 cerebra salary, and # 7 slow gain. The early research direction focused on the development of exoskeleton robots, verifying their reliability and feasibility. Later, the focus was on the combination of exoskeleton robot with machine learning and other technologies, rehabilitation costs, and patient quality of life.

Conclusion

This study provides a visual display of the research status, development trends, and research hotspots, which helps researchers in this field to grasp the research hotspots and choose future research directions.

Low-force human-human hand interactions induce gait changes through sensorimotor engagement instead of direct mechanical effects

Physical human-robot interactions (pHRI) often provide mechanical force and power to aid walking without requiring voluntary effort from the human. Alternatively, principles of physical human-human interactions (pHHI) can inspire pHRI that aids walking by engaging human sensorimotor processes. We hypothesize that low-force pHHI can intuitively induce a person to alter their walking through haptic communication. In our experiment, an expert partner dancer influenced novice participants to alter step frequency solely through hand interactions. Without prior instruction, training, or knowledge of the expert's goal, novices decreased step frequency 29% and increased step frequency 18% based on low forces (< 20 N) at the hand. Power transfer at the hands was 3-700 × smaller than what is necessary to propel locomotion, suggesting that hand interactions did not mechanically constrain the novice's gait. Instead, the sign/direction of hand forces and power may communicate information about how to alter walking. Finally, the expert modulated her arm effective dynamics to match that of each novice, suggesting a bidirectional haptic communication strategy for pHRI that adapts to the human. Our results provide a framework for developing pHRI at the hand that may be applicable to assistive technology and physical rehabilitation, human-robot manufacturing, physical education, and recreation.

Powered single hip joint exoskeletons for gait rehabilitation: a systematic review and Meta-analysis

BACKGROUND

Gait disorders and as a consequence, robotic rehabilitation techniques are becoming increasingly prevalent as the population ages. In the area of rehabilitation robotics, using lightweight single hip joint exoskeletons are of significance. Considering no prior systematic review article on clinical outcomes, we aim to systematically review powered hip exoskeletons in terms of gait parameters and metabolic expenditure effects.

METHODS

Three databases of PubMed, Scopus, and Web of science were searched for clinical articles comparing outcomes of gait rehabilitation using hip motorized exoskeleton with conventional methods, on patients with gait disorder or healthy individuals. Of total number of 37 reviewed articles, 14 trials were quantitatively analyzed. Analyses performed in terms of gait spatiotemporal parameters like speed (self-speed and maximum speed), step length, stride length, cadence, and oxygen consumption.

RESULTS

Improved clinical outcomes of gait spatiotemporal parameters with hip joint exoskeletons are what our review's findings show. In terms of gait values, meta-analysis indicates that rehabilitation with single hip joint exoskeleton enhanced parameters of maximum speed by 0.13 m/s (0.10-0.17) and step length by 0.06 m (0.05-0.07). For the remaining investigated gait parameters, no statistically significant difference was observed. Regarding metabolic parameters, oxygen consumption was lower in individuals treated with hip exoskeleton (- 1.23 ml/min/kg; range - 2.13 to - 0.32).

CONCLUSION

Although the analysis demonstrated improvement with just specific gait measures utilizing powered hip exoskeletons, the lack of improvement in all parameters is likely caused by the high patient condition heterogeneity among the evaluated articles. We also noted in patients who rehabilitated with the hip exoskeleton, the oxygen cost was lower. More randomized controlled trials are needed to verify both the short- and long-term clinical outcomes, including patient-reported measures.

LEVEL OF EVIDENCE

Level I (systematic review and meta-analysis).

Effects of soft robotic exoskeleton for gait training on clinical and biomechanical gait outcomes in patients with sub-acute stroke: a randomized controlled pilot study

Background

Ankle function impairment is a critical factor impairing normal walking in survivors of stroke. The soft robotic exoskeleton (SRE) is a novel, portable, lightweight assistive device with promising therapeutic potential for gait recovery during post-stroke rehabilitation. However, whether long-term SRE-assisted walking training influences walking function and gait quality in patients following subacute stroke is unknown. Therefore, the primary objective of this study was to assess the therapeutic effects of SRE-assisted walking training on clinical and biomechanical gait outcomes in the rehabilitation of patients with subacute stroke.

Methods

A group patients who had experienced subacute stroke received conventional rehabilitation (CR) training combined with 10-session SRE-assisted overground walking training (30 min per session, 5 sessions/week, 2 weeks) (SRE group, n = 15) compared with the control group that received CR training only (CR group, n = 15). Clinical assessments and biomechanical gait quality measures were performed pre-and post-10-session intervention, with the 10-Minute Walk Test (10MWT) and 6-Minute Walk Test (6MWT) used to define the primary clinical outcome measures and the Functional Ambulation Category, Fugl-Meyer Assessment for Lower Extremity (FMA-LE) subscale, and Berg Balance Scale defined the secondary outcome measures. The gait quality outcome measures included spatiotemporal and symmetrical parameters during walking.

Results

After the 10-session intervention, the SRE and CR groups exhibited significant within-group improvements in all clinical outcome measures (p < 0.05). Between-comparison using covariance analyses demonstrated that the SRE group showed greater improvement in walking speed during the 10MWT (p < 0.01), distance walked during the 6MWT (p < 0.05), and FMA-LE scores (p < 0.05). Gait analyses showed that the SRE group exhibited significantly improved spatiotemporal symmetry (p < 0.001) after 10-session training, with no significant changes observed in the CR group.

Conclusion

Compared with CR training, SRE-assisted walking training led to greater improvements in walking speed, endurance, and motor recovery. Our findings provide preliminary evidence that SRE may be considered for inclusion in intensive gait training clinical rehabilitation programs to further improve walking function in patients who have experienced stroke.

Users' experiences of intensive robotic-assisted gait training post-stroke - "a push forward or feeling pushed around?"

PURPOSE

Robotic-assisted gait training (RAGT) is suggested to improve walking ability after stroke. The purpose of this study was to describe experiences of robotic-assisted gait training as part of a gait training intervention among persons in the chronic phase after stroke.

MATERIALS AND METHODS

Semi-structured interviews were performed with 13 participants after a 6-week intervention including treadmill gait training with the Hybrid Assistive Limb® (HAL) exoskeleton. Data were analysed using qualitative content analysis.

RESULTS

Four categories emerged: (1) A rare opportunity for potential improvements describes the mindset before the start of the intervention; (2) Being pushed to the limit represents the experience of engaging in intensive gait training; (3) Walking with both resistance and constraints reveals barriers and facilitators during HAL training; (4) Reaching the end and taking the next step alone illustrates feelings of confidence or concern as the intervention ended.

CONCLUSIONS

The gait training intervention including RAGT was considered demanding but appreciated. Support and concrete, individual feedback was crucial for motivation, whilst the lack of variation was a barrier. Results encourage further development of exoskeletons that are comfortable to wear and stimulate active participation by enabling smoothly synchronised movements performed during task-specific activities in different environments. IMPLICATIONS FOR REHABILITATIONWhen provided in a suitable context, the mental and physical challenges of intensive robotic-assisted gait training can be both inspiring and motivating.Support and engagement along with informative feedback from therapists are suggested crucial for motivation.Intensive task-specific gait training may preferably be performed in an enriched environment and combined with other physiotherapy treatments to stimulate engagement.

Gait pattern after electromechanically-assisted gait training with the Hybrid Assistive Limb and conventional gait training in sub-acute stroke rehabilitation-A subsample from a randomized controlled trial

Introduction

Electromechanically-assisted gait training has been introduced in stroke rehabilitation as a means to enable gait training with a large number of reproducible and symmetrical task repetitions, i.e. steps. However, few studies have evaluated its impact on gait pattern functions. This study includes persons with no independent ambulation function at the start of a 4-week neurorehabilitation period in the sub-acute phase after stroke. The primary aim of the study was to evaluate whether the addition of electromechanically-assisted gait training to conventional training resulted in better gait pattern function than conventional training alone. The secondary aim was to identify correlations between overall gait quality and standardized clinical assessments.

Participants and methods

Seventeen patients with no independent ambulation function who participated in a Prospective Randomized Open Blinded End-point study in the sub-acute phase after stroke were randomized into two groups; one group (n = 7) to undergo conventional training only (CONV group) and the other group (n = 10) to undergo conventional training with additional electromechanically-assisted gait training (HAL group). All patients were assessed with 3D gait analysis and clinical assessments after the 4-week intervention period. Overall gait quality as per the Gait Profile Score (GPS), as well as kinematic, and kinetic and other spatiotemporal metrics were collected and compared between intervention groups. Correlations between biomechanical and clinical outcomes were evaluated.

Results

Both the CONV and HAL groups exhibited similar gait patterns with no significant differences between groups in any kinematic, kinetic parameters or other spatiotemporal metrics. The GPS for the paretic limb had a median (IQR) of 12.9° (7.8°) and 13.4° (4.3°) for the CONV and HAL groups, respectively (p = 0.887). Overall gait quality was correlated with independence in walking, walking speed, movement function and balance. We found no added benefit in gait pattern function from the electromechanically-assisted gait training compared to the conventional training alone.

Discussion

This finding raises new questions about how to best design effective and optimal post-stroke rehabilitation programs in patients with moderate to severe gait impairments to achieve both independent walking and optimal gait pattern function, and about which patients should be in focus in further studies on the efficacy of electromechanically-assisted gait training.

Clinical trial registration

The study was retrospectively registered at ClinicalTrials.gov, identifier (NCT02410915) on April 2015.

Biomechanics of Exoskeleton-Assisted Treadmill Walking

To exploit the benefits of treadmill-based exoskeletons, it is crucial to assess possible deviations from natural walking depending on assistive parameters. This study evaluated the biomechanics of exoskeleton-assisted treadmill walking by comparing it with free gait. Five healthy participants walked freely on a treadmill and with the assistance of the Lokomat gait trainer, while changing Body Weight Support (BWS), Gait Speed (GS), and Guidance Force (GF). Results showed that the hip and knee joint kinematics depended on BWS and GS, while changes due to GF were limited. Moreover, joint kinematics and the activity of related muscles were altered with respect to free gait, for any combination of robot parameters in the case of the ankle, and especially for low GS and with BWS in the case of hip and knee. Overall, walking with the Lokomat can mostly resemble free gait at high speed and without BWS.

Re-learning mental representation of walking after a brain lesion. Effects of a cognitive-motor training with a robotic orthosis

Introduction

Stroke-related deficits often include motor impairments and gait dysfunction, leading to a limitation of social activities and consequently affecting the quality of life of stroke survivors. Neurorehabilitation takes advantage of the contribution of different techniques in order to achieve more benefits for patients. Robotic devices help to improve the outcomes of physical rehabilitation. Moreover, motor imagery seems to play a role in neurological rehabilitation since it leads to the activation of the same brain areas as actual movements. This study investigates the use of a combined physical and cognitive protocol for gait rehabilitation in stroke patients.

Methods

Specifically, we tested the efficacy of a 5-week training program using a robotic orthosis (P.I.G.R.O.) in conjunction with motor imagery training. Twelve chronic stroke patients participated in the study. We evaluated balance and gait performance before and after the training. Six of them underwent fMRI examination before and after the training to assess the effects of the protocol on brain plasticity mechanisms in motor and imagery tasks.

Results

Our results show that the rehabilitation protocol can effectively improve gait performance and balance and reduce the risk of falls in stroke patients. Furthermore, the fMRI results suggest that rehabilitation is associated with cerebral plastic changes in motor networks.

Discussion

The present findings, if confirmed by future research, have the potential to advance the development of new, more effective rehabilitation approaches for stroke patients, improving their quality of life and reducing the burden of stroke-related disability.

New Neuromuscular Training for Peripheral Nerve Disorders Using an Ankle Joint Hybrid Assistive Limb: A Case Series

Peripheral nerve disorder of the lower extremities causes drop foot and disturbs the daily living activities of patients. The ankle joint hybrid assistive limb (HAL) provides voluntary ankle joint training using surface bioelectrical signals from the muscles of the lower extremities. We investigated the neurological effects of ankle joint HAL training in three patients. Sensory nerve action potentials (SNAPs) and compound muscle action potentials (CMAPs) were analyzed for the peroneal and tibial nerves prior to the first ankle joint HAL training session. Integrated surface electromyography EMG signals were recorded before and after the HAL training sessions to evaluate the effects of training for neuromuscular disorders. The patients were hospitalized to receive rehabilitation with HAL training for 2 weeks. The HAL training was performed daily with two 60 min sessions. All cases demonstrated severe neuromuscular impairment according to the result of the CMAP. All integrated EMG measurements of antagonistic muscle activities decreased after the ankle joint HAL training. The manual muscle testing (MMT) scores of each muscle were slightly increased after the HAL intervention for Case 2(tibialis anterior, from 2 to 2+; gastrocnemius muscles, from 2- to 2; extensor digitorum longus, and extensor hallucis longus, from 1 to 3). The MMT scores were also slightly increased except for gastrocnemius muscle for Case 3 (tibialis anterior, extensor digitorum longus, and extensor hallucis longus, from 2- to 2). These two patients demonstrated voluntary muscle contractions and nerve signals in the CMAP before the HAL training. Even though the amplitude of CMAPs was low, the HAL training may provide voluntary ankle joint movements by reducing the antagonistic muscle contraction via computer processing. The HAL training may enhance muscle movement and coordination through motor learning feedback.

Benefits of a Wearable Cyborg HAL (Hybrid Assistive Limb) in Patients with Childhood-Onset Motor Disabilities: A 1-Year Follow-Up Study

Rehabilitation robots have shown promise in improving the gait of children with childhood-onset motor disabilities. This study aimed to investigate the long-term benefits of training using a wearable Hybrid Assistive Limb (HAL) in these patients. Training using a HAL was performed for 20 min a day, two to four times a week, over four weeks (12 sessions in total). The Gross Motor Function Measure (GMFM) was the primary outcome measure, and the secondary outcome measures were gait speed, step length, cadence, 6-min walking distance (6MD), Pediatric Evaluation of Disability Inventory, and Canadian Occupational Performance Measure (COPM). Patients underwent assessments before the intervention, immediately after the intervention, and at 1-, 2-, 3-month and 1-year follow-ups. Nine participants (five males, four females; mean age: 18.9 years) with cerebral palsy (n = 7), critical illness polyneuropathy (n = 1), and encephalitis (n = 1) were enrolled. After training using HAL, GMFM, gait speed, cadence, 6MD, and COPM significantly improved (all p < 0.05). Improvements in GMFM were maintained one year after the intervention (p < 0.001) and in self-selected gait speed and 6MD three months after the intervention (p < 0.05). Training using HAL may be safe and feasible for childhood-onset motor disabilities and may maintain long-term improvements in motor function and walking ability.

The effect of robot-assisted gait training frequency on walking, functional recovery, and quality of life in patients with stroke

AIM

This study aims to investigate the effects of robot-assisted gait training (RAGT) frequency on walking, functional recovery, QoL and mood.

METHODS

Sixty patients aged 50-75, diagnosed with post-stroke hemiplegia were entered into the retrospective analysis. Participants who scored maximum 3 on the Modified Rankin Scale and were diagnosed with moderate stroke according to The NIH Stroke Scale were included in the study. The participants in group 1 (G1) received only conventional treatment (CT), in group 2 (G2) participants received one session of RAGT per week in addition to the CT program, and group 3 (G3) received two sessions of RAGT per week in addition to the CT program. 6-min walk test (6-MWT), Barthel Index (BI), Stroke-Specific Quality of Life Scale (SSQoL), and Beck Depression Inventory (BDI) were recorded.

RESULTS

Median change in SSQoL of G3 was significantly higher from median change of G1 (p < 0.05), and median change in BDI of G3 was significantly lower than median change of G1 (p < 0.05). Median change in BDI of G3 was also significantly lower from change of G2 (p < 0.05).

CONCLUSION

Two weekly sessions of RAGT in addition to CT exhibit positive effects on QoL and mood but no additional contribution to functional status.

Opportunities and challenges in the development of exoskeletons for locomotor assistance

Exoskeletons can augment the performance of unimpaired users and restore movement in individuals with gait impairments. Knowledge of how users interact with wearable devices and of the physiology of locomotion have informed the design of rigid and soft exoskeletons that can specifically target a single joint or a single activity. In this Review, we highlight the main advances of the past two decades in exoskeleton technology and in the development of lower-extremity exoskeletons for locomotor assistance, discuss research needs for such wearable robots and the clinical requirements for exoskeleton-assisted gait rehabilitation, and outline the main clinical challenges and opportunities for exoskeleton technology.

Effectiveness of Rehabilitation Exercise in Improving Physical Function of Stroke Patients: A Systematic Review

Rehabilitation is a crucial part of recovery for stroke survivors, and numerous studies have examined various exercises and treatments of stroke. In addition, it is very important for patients to choose the timing of rehabilitation and what kind of rehabilitation they will proceed with. The purpose of the current study is to examine research investigating the effects of rehabilitation exercise programs in recovery of physical function in patients with stroke, based on aspects of their physical function, physical strength, and daily activities, and systematically examine their effects. Therefore, through systematic review, we have investigated the effects of interventions in rehabilitation exercise programs for recovery of physical function in patients with stroke. We collected relevant publications through the databases MEDLINE/PubMed and Google scholar. Twenty-one articles were ultimately selected for the analysis. We classified the rehabilitation programs and identified the trends of treatment for stroke survivors. Our review indicated that task-oriented therapy is still dominant, but various types of combined rehabilitations have been attempted. In addition, it was identified that physical and active rehabilitation were required rather than unconditional rest, even at an early stage. Home-based treatment was used for rapid recovery and adaptation to daily life during the mid-term period.

Short and long-term effects of robot-assisted therapy on upper limb motor function and activity of daily living in patients post-stroke: a meta-analysis of randomized controlled trials

Objective

To investigate the effect of robot-assisted therapy (RAT) on upper limb motor control and activity function in poststroke patients compared with that of non-robotic therapy.

Methods

We searched PubMed, EMBASE, Cochrane Library, Google Scholar and Scopus. Randomized controlled trials published from 2010 to nowadays comparing the effect of RAT and control treatment on upper limb function of poststroke patients aged 18 or older were included. Researchers extracted all relevant data from the included studies, assessed the heterogeneity with inconsistency statistics (I² statistics), evaluated the risk of bias of individual studies and performed data analysis.

Result

Forty-six studies were included. Meta-analysis showed that the outcome of the Fugl-Meyer Upper Extremity assessment (FM-UE) (SMD = 0.20, P = 0.001) and activity function post intervention was significantly higher (SMD = 0.32, P < 0.001) in the RAT group than in the control group. Differences in outcomes of the FM-UE and activity function between the RAT group and control group were observed at the end of treatment and were not found at the follow-up. Additionally, the outcomes of the FM-UE (SMD = 0.15, P = 0.005) and activity function (SMD = 0.32, P = 0.002) were significantly different between the RAT and control groups only with a total training time of more than 15 h. Moreover, the differences in outcomes of FM-UE and activity post intervention were not significant when the arm robots were applied to patients with severe impairments (FM-UE: SMD = 0.14, P = 0.08; activity: SMD = 0.21, P = 0.06) or when patients were provided with patient-passive training (FM-UE: SMD = − 0.09, P = 0.85; activity: SMD = 0.70, P = 0.16).

Conclusion

RAT has the significant immediate benefits for motor control and activity function of hemiparetic upper limb in patients after stroke compared with controls, but there is no evidence to support its long-term additional benefits. The superiority of RAT in improving motor control and activity function is limited by the amount of training time and the patients' active participation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12984-022-01058-8.

Is robot-assisted gait training intensity a determinant of functional recovery early after stroke? A pragmatic observational study of clinical care

Gait rehabilitation is a critical factor in functional recovery after a stroke. The aim of this pragmatic observational study was to identify the optimal dose and timing of robot-assisted gait training (RAGT) that can lead to a favourable outcome in a sample of subacute stroke survivors. Subacute patients with stroke who underwent a RAGT within a multidisciplinary rehabilitation program were enrolled. A set of clinical (i.e. age, type of stroke and time since stroke) and rehabilitation stay outcomes (length of stay and RAGT number of sessions) were recorded to evaluate their impact on functional outcome measures by functional independence measure (FIM) or functional ambulation category (FAC). We included 236 patients (62.73 ± 11.82 year old); 38.44% were females, and 59.32% were ischaemic stroke patients. Patients that received at least 14 RAGT sessions, had 15.83% more chance to be responders compared to those that receive less sessions (P = 0.006). Similarly, younger patients (≤60 years) were more prone to be responders (+15.1%). Lastly, an early rehabilitation (<6 weeks) was found to be more efficient (+21.09%) in determining responsiveness (P < 0.001). Becoming newly independent for gait, that refers to a FAC score ≥4, was related with age and RAGT sessions (P = 0.001). In conclusion, a younger age (≤60 years), an early rehabilitation (<6 weeks since stroke) and a higher RAGT dose (at least 14 sessions) were related to a favourable outcome in patients with subacute stroke.

Efficacy of Overground Robotic Gait Training on Balance in Stroke Survivors: A Systematic Review and Meta-Analysis

Strokes often lead to a deficit in motor control that contributes to a reduced balance function. Impairments in the balance function severely limit the activities of daily living (ADL) in stroke survivors. The present systematic review and meta-analysis primarily aims to explore the efficacy of overground robot-assisted gait training (o-RAGT) on balance recovery in individuals with stroke. In addition, the efficacy on ADL is also investigated. This systematic review identified nine articles investigating the effects of o-RAGT on balance, four of which also assessed ADL. The results of the meta-analysis suggest that o-RAGT does not increase balance and ADL outcomes more than conventional therapy in individuals after stroke. The data should not be overestimated due to the low number of studies included in the meta-analysis and the wide confidence intervals. Subgroup analyses to investigate the influence of participant’s characteristics and training dosage were not performed due to lack of data availability. Further well-designed randomized controlled trials are needed to investigate the efficacy of o-RAGT on balance in individuals with stroke.

Stance Phase Gait Training Post Stroke Using Simultaneous Transcranial Direct Current Stimulation and Motor Learning-Based Virtual Reality-Assisted Therapy: Protocol Development and Initial Testing

Gait deficits are often persistent after stroke, and current rehabilitation methods do not restore normal gait for everyone. Targeted methods of focused gait therapy that meet the individual needs of each stroke survivor are needed. Our objective was to develop and test a combination protocol of simultaneous brain stimulation and focused stance phase training for people with chronic stroke (>6 months). We combined Transcranial Direct Current Stimulation (tDCS) with targeted stance phase therapy using Virtual Reality (VR)-assisted treadmill training and overground practice. The training was guided by motor learning principles. Five users (>6 months post-stroke with stance phase gait deficits) completed 10 treatment sessions. Each session began with 30 min of VR-assisted treadmill training designed to apply motor learning (ML)-based stance phase targeted practice. During the first 15 min of the treadmill training, bihemispheric tDCS was simultaneously delivered. Immediately after, users completed 30 min of overground (ML)-based gait training. The outcomes included the feasibility of protocol administration, gait speed, Timed Up and Go (TUG), Functional Gait Assessment (FGA), paretic limb stance phase control capability, and the Fugl−Meyer for lower extremity coordination (FMLE). The changes in the outcome measures (except the assessments of stance phase control capability) were calculated as the difference from baseline. Statistically and clinically significant improvements were observed after 10 treatment sessions in gait speed (0.25 ± 0.11 m/s) and FGA (4.55 ± 3.08 points). Statistically significant improvements were observed in TUG (2.36 ± 3.81 s) and FMLE (4.08 ± 1.82 points). A 10-session intervention combining tDCS and ML-based task-specific gait rehabilitation was feasible and produced clinically meaningful improvements in lower limb function in people with chronic gait deficits after stroke. Because only five users tested the new protocol, the results cannot be generalized to the whole population. As a contribution to the field, we developed and tested a protocol combining brain stimulation and ML-based stance phase training for individuals with chronic stance phase deficits after stroke. The protocol was feasible to administer; statistically and/or clinically significant improvements in gait function across an array of gait performance measures were observed with this relatively short treatment protocol.

A Robot-Assisted Therapy to Increase Muscle Strength in Hemiplegic Gait Rehabilitation

This study examines the feasibility of using a robot-assisted therapy methodology based on the Bobath concept to perform exercises applied in conventional therapy for gait rehabilitation in stroke patients. The aim of the therapy is to improve postural control and movement through exercises based on repetitive active-assisted joint mobilization, which is expected to produce strength changes in the lower limbs. As therapy progresses, robotic assistance is gradually reduced and the patient's burden increases with the goal of achieving a certain degree of independence. The relationship between force and range of motion led to the analysis of both parameters of interest. The study included 23 volunteers who performed 24 sessions, 2 sessions per week for 12 weeks, each lasting about 1 h. The results showed a significant increase in hip abduction and knee flexion strength on both sides, although there was a general trend of increased strength in all joints. However, the range of motion at the hip and ankle joints was reduced. The usefulness of this platform for transferring exercises from conventional to robot-assisted therapies was demonstrated, as well as the benefits that can be obtained in muscle strength training. However, it is suggested to complement the applied therapy with exercises for the maintenance and improvement of the range of motion.

Development of a New Ankle Joint Hybrid Assistive Limb

Foot and ankle disabilities (foot drop) due to common peroneal nerve palsy and stroke negatively affect patients’ ambulation and activities of daily living. We developed a novel robotics ankle hybrid assistive limb (HAL) for patients with foot drop due to common peroneal nerve palsy or stroke. The ankle HAL is a wearable exoskeleton-type robot that is used to train plantar and dorsiflexion and for voluntary assistive training of the ankle joint of patients with palsy using an actuator, which is placed on the lateral side of the ankle joint and detects bioelectrical signals from the tibialis anterior (TA) and gastrocnemius muscles. Voluntary ankle dorsiflexion training using the new ankle HAL was implemented in a patient with foot drop due to peroneal nerve palsy after lumbar surgery. The time required for ankle HAL training (from wearing to the end of training) was approximately 30 min per session. The muscle activities of the TA on the right were lower than those on the left before and after ankle HAL training. The electromyographic wave of muscle activities of the TA on the right was slightly clearer than that before ankle HAL training in the resting position immediately after ankle dorsiflexion. Voluntary ankle dorsiflexion training using the novel robotics ankle HAL was safe and had no adverse effect in a patient with foot drop due to peroneal nerve palsy.

Identification of Lower-Limb Motor Tasks via Brain–Computer Interfaces: A Topical Overview

Recent engineering and neuroscience applications have led to the development of brain–computer interface (BCI) systems that improve the quality of life of people with motor disabilities. In the same area, a significant number of studies have been conducted in identifying or classifying upper-limb movement intentions. On the contrary, few works have been concerned with movement intention identification for lower limbs. Notwithstanding, lower-limb neurorehabilitation is a major topic in medical settings, as some people suffer from mobility problems in their lower limbs, such as those diagnosed with neurodegenerative disorders, such as multiple sclerosis, and people with hemiplegia or quadriplegia. Particularly, the conventional pattern recognition (PR) systems are one of the most suitable computational tools for electroencephalography (EEG) signal analysis as the explicit knowledge of the features involved in the PR process itself is crucial for both improving signal classification performance and providing more interpretability. In this regard, there is a real need for outline and comparative studies gathering benchmark and state-of-art PR techniques that allow for a deeper understanding thereof and a proper selection of a specific technique. This study conducted a topical overview of specialized papers covering lower-limb motor task identification through PR-based BCI/EEG signal analysis systems. To do so, we first established search terms and inclusion and exclusion criteria to find the most relevant papers on the subject. As a result, we identified the 22 most relevant papers. Next, we reviewed their experimental methodologies for recording EEG signals during the execution of lower limb tasks. In addition, we review the algorithms used in the preprocessing, feature extraction, and classification stages. Finally, we compared all the algorithms and determined which of them are the most suitable in terms of accuracy.

Effect of Reciprocating Gait Orthosis with Hip Actuation on Upper Extremity Loading during Ambulation in Patient with Spinal Cord Injury: A Single Case Study

Reciprocating gait orthosis (RGO) is a traditional passive orthosis that provides postural stability and allows for independent upright ambulation with the assistance of walking aids, such as crutches, canes, and walkers. Previous follow-up studies of patients with RGOs have indicated a high frequency of nonusage. One of the main reasons for avoiding the use of RGOs is the excessive upper extremity loading induced by walking aids. The purpose of this study was to investigate the effect of hip actuation on the upper extremity loading induced by crutches when ambulating with an RGO. One female individual with a chronic complete spinal cord injury classified as ASIA A participated in this study. We compared the upper extremity loading during ambulation when individualized hip assistive forces were applied on the RGO (POWERED condition) and when wearing the RGO without actuation (RGO condition). Upper extremity loading was assessed by measuring the forces acting on the crutches. Compared with the RGO condition, the average upper extremity loading per unit distance and per unit time were lower for the POWERED condition by 15.21% (RGO: 0.307 ± 0.056 and POWERED: 0.260 ± 0.034 %bw·m−1) and by 21.19% (RGO: 0.120 ± 0.020 and POWERED: 0.094 ± 0.011 %bw·s−1), respectively. We believe that a substantial reduction in upper extremity loading during ambulation provided by hip actuation holds promise to promote long-term RGO use and enable patients with paraplegia to perform frequent and intensive rehabilitation training. As this is a single case study, subsequent studies should aim to verify this effect through a higher number of patients and to different injury levels.

Ankle dorsiflexion training with a newly developed Hybrid Assistive Limb for a patient with foot drop caused by common peroneal nerve palsy: a case report

[Purpose] An ankle disorder (foot drop) caused by common peroneal nerve palsy or cerebrovascular accident (stroke) interferes with patients’ ability to walk and hinders in activities of daily living. A new robotic ankle, the Hybrid Assistive Limb, has been developed for the treatment of foot drop caused by common peroneal nerve palsy or sequelae of stroke. The purpose in this study was to report and examine the efficacy and feasibility of a case who was treated with voluntary ankle dorsiflexion training with the ankle Hybrid Assistive Limb. [Participant and Method] A 60-year-old man with foot drop due to peroneal nerve palsy that occurred without a contributory cause was treated via ankle dorsiflexion training with the use of a new robotic ankle, the “Ankle Hybrid Assistive Limb”. [Results] Following total ankle rehabilitation training with the Ankle Hybrid Assistive Limb, improvements in ankle dorsiflexor strength, gait, and sensory function of the lower leg and foot were observed. [Conclusion] The newly developed ankle Hybrid Assistive Limb could be an effective training tool for foot drop caused by common peroneal nerve palsy.

The effect of pelvic movements of a gait training system for stroke patients: a single blind, randomized, parallel study

BACKGROUND

Aging societies lead to higher demand for gait rehabilitation as age-related neurological disorders such as stroke and spinal cord injury increase. Since conventional methods for gait rehabilitation are physically and economically burdensome, robotic gait training systems have been studied and commercialized, many of which provided movements confined in the sagittal plane. For better outcomes of gait rehabilitation with more natural gait patterns, however, it is desirable to provide pelvic movements in the transverse plane. In this study, a robotic gait training system capable of pelvic motions in the transverse plane was used to evaluate the effect of the pelvic motions on stroke patients.

METHOD

Healbot T, which is a robotic gait training system and capable of providing pelvic movements in the transverse plane as well as flexion/extension of the hip and knee joints and adduction/abduction of the hip joints, is introduced and used to evaluate the effect of the pelvic movement on gait training of stroke patients. Gait trainings in Healbot T with and without pelvic movements are carried out with stroke patients having hemiparesis.

EXPERIMENT

Twenty-four stroke patients with hemiparesis were randomly assigned into two groups and 23 of them successfully completed the experiment except one subject who had dropped out due to personal reasons. Pelvis-on group was provided with pelvic motions whereas no pelvic movement was allowed for pelvis-off group during 10 sessions of gait trainings in Healbot T. Electromyography (EMG) signals and interaction forces as well as the joint angles of the robot were measured. Gait parameters such as stride length, cadence, and walking speed were measured while walking on the ground without assistance of Healbot T after gait training on 1st, 5th, and 10th day.

RESULT

Stride length significantly increased in both groups. Furthermore, cadence and walking speed of the pelvis-on group were increased by 10.6% and 11.8%. Although interaction forces of both groups except the thighs showed no differences, EMG signals from gluteus medius of the pelvis-on group increased by 88.6% during stance phase. In addition, EMG signals of biceps femoris, gastrocnemius medial, and gastrocnemius lateral of the pelvis-on group increased whereas EMG signals of the pelvis-off group except gastrocnemius lateral showed no difference after gait trainings.

CONCLUSION

Gait training using a robotic gait training system with pelvic movements was conducted to investigate the effects of lateral and rotational pelvic movements in gait training of stroke patients. The pelvic movements affected to increase voluntary muscle activation during the stance phase as well as cadence and walking speed.

CLINICAL TRIAL REGISTRATION

KCT0003762, 2018-1254, Registered 28 October 2018, https://cris.nih.go.kr/cris/search/search_result_st01_kren.jsp?seq=14310&ltype=&rtype=.

Neglected physical human-robot interaction may explain variable outcomes in gait neurorehabilitation research

[Figure: see text].

Efficacy of a Novel Exoskeletal Robot for Locomotor Rehabilitation in Stroke Patients: A Multi-center, Non-inferiority, Randomized Controlled Trial

Objective: To investigate the efficacy and safety of a novel lower-limb exoskeletal robot, BEAR-H1 (Shenzhen Milebot Robot Technology), in the locomotor function of subacute stroke patients. Methods: The present study was approved by the ethical committee of the First Affiliated Hospital of Nanjing Medical University (No. 2019-MD-43), and registration was recorded on the Chinese Clinical Trial Registry with a unique identifier: ChiCTR2100044475. A total of 130 patients within 6 months of stroke were randomly divided into two groups: the robot group and the control group. The control group received routine training for walking, while in the robot group, BEAR-H1 lower-limb exoskeletal robot was used for locomotor training. Both groups received two sessions daily, 5 days a week for 4 weeks consecutively. Each session lasted 30 min. Before treatment, after treatment for 2 weeks, and 4 weeks, the patients were assessed based on the 6-minute walking test (6MWT), functional ambulation scale (FAC), Fugl-Meyer assessment lower-limb subscale (FMA-LE), and Vicon gait analysis. Results: After a 4-week intervention, the results of 6MWT, FMA-LE, FAC, cadence, and gait cycle in the two groups significantly improved (P < 0.05), but there was no significant difference between the two groups (P > 0.05). The ratio of stance phase to that of swing phase, swing phase symmetry ratio (SPSR), and step length symmetry ratio (SLSR) was not significantly improved after 4 weeks of training in both the groups. Further analyses revealed that the robot group exhibited potential benefits, as the point estimates of 6MWT and Δ6MWT (post-pre) at 4 weeks were higher than those in the control group. Additionally, within-group comparison showed that patients in the robot group had a significant improvement in 6MWT earlier than their counterparts in the control group. Conclusions: The rehabilitation robot in this study could improve the locomotor function of stroke patients; however, its effect was no better than conventional locomotor training.

Deep-Learning-Based Emergency Stop Prediction for Robotic Lower-Limb Rehabilitation Training Systems

Robotic lower-limb rehabilitation training is a better alternative for the physical training efforts of a therapist due to advantages, such as intensive repetitive motions, economical therapy, and quantitative assessment of the level of motor recovery through the measurement of force and movement patterns. However, in actual robotic rehabilitation training, emergency stops occur frequently to prevent injury to patients. However, frequent stopping is a waste of time and resources of both therapists and patients. Therefore, early detection of emergency stops in real-time is essential to take appropriate actions. In this paper, we propose a novel deep-learning-based technique for detecting emergency stops as early as possible. First, a bidirectional long short-term memory prediction model was trained using only the normal joint data collected from a real robotic training system. Next, a real-time threshold-based algorithm was developed with cumulative error. The experimental results revealed a precision of 0.94, recall of 0.93, and F1 score of 0.93. Additionally, it was observed that the prediction model was robust for variations in measurement noise.

Effect of robotic-assisted gait training on objective biomechanical measures of gait in persons post-stroke: a systematic review and meta-analysis

BACKGROUND

Robotic-Assisted Gait Training (RAGT) may enable high-intensive and task-specific gait training post-stroke. The effect of RAGT on gait movement patterns has however not been comprehensively reviewed. The purpose of this review was to summarize the evidence for potentially superior effects of RAGT on biomechanical measures of gait post-stroke when compared with non-robotic gait training alone.

METHODS

Nine databases were searched using database-specific search terms from their inception until January 2021. We included randomized controlled trials investigating the effects of RAGT (e.g., using exoskeletons or end-effectors) on spatiotemporal, kinematic and kinetic parameters among adults suffering from any stage of stroke. Screening, data extraction and judgement of risk of bias (using the Cochrane Risk of bias 2 tool) were performed by 2-3 independent reviewers. The Grading of Recommendations Assessment Development and Evaluation (GRADE) criteria were used to evaluate the certainty of evidence for the biomechanical gait measures of interest.

RESULTS

Thirteen studies including a total of 412 individuals (mean age: 52-69 years; 264 males) met eligibility criteria and were included. RAGT was employed either as monotherapy or in combination with other therapies in a subacute or chronic phase post-stroke. The included studies showed a high risk of bias (n = 6), some concerns (n = 6) or a low risk of bias (n = 1). Meta-analyses using a random-effects model for gait speed, cadence, step length (non-affected side) and spatial asymmetry revealed no significant differences between the RAGT and comparator groups, while stride length (mean difference [MD] 2.86 cm), step length (affected side; MD 2.67 cm) and temporal asymmetry calculated in ratio-values (MD 0.09) improved slightly more in the RAGT groups. There were serious weaknesses with almost all GRADE domains (risk of bias, consistency, directness, or precision of the findings) for the included outcome measures (spatiotemporal and kinematic gait parameters). Kinetic parameters were not reported at all.

CONCLUSION

There were few relevant studies and the review synthesis revealed a very low certainty in current evidence for employing RAGT to improve gait biomechanics post-stroke. Further high-quality, robust clinical trials on RAGT that complement clinical data with biomechanical data are thus warranted to disentangle the potential effects of such interventions on gait biomechanics post-stroke.

Adjustment effect during shoulder abduction training with the Hybrid Assistive Limb in a patient with postoperative C5 palsy

Standard shoulder rehabilitation procedures for patients with postoperative C5 palsy have not yet been established. We applied a wearable robot suit hybrid assistive limb (HAL) for a patient with postoperative C5 palsy and conducted shoulder abduction training with HAL. A 65-year-old woman was diagnosed with postoperative C5 palsy after undergoing cervical spine surgery. Five days after surgery, shoulder abduction training with HAL was initiated. The shoulder abduction angle and power and trapezius and deltoid activities were evaluated. Ten rehabilitation sessions were conducted until 82 days after surgery. Shoulder abduction training was safely and effectively performed from the first session. Her shoulder abduction angle and power improved at every session, and she could fully elevate her arm without any compensatory motion after the 10th session. Shoulder HAL training suppressed the muscular activity of the trapezius and activated that of the deltoid, especially in the earlier stages of rehabilitation. Moreover, it had an adjustment effect for obtaining normal shoulder motion, which might have promoted smoother arm elevation using errorless motor learning. These findings suggest that HAL is a useful tool for shoulder rehabilitation in patients with postoperative C5 palsy.

Staged treatment protocol for gait with hybrid assistive limb in the acute phase of patients with stroke

Hybrid Assistive Limb (HAL) is a wearable human assistant cyborg-type robot that helps lower-leg movement based on bioelectrical signals detected from the voluntary movement of the person wearing it. In this study, we developed a novel staged HAL treatment protocol for patients with acute stroke. The Regain Program for Gait with HAL (RPG-HAL) was formulated in four steps, based on the severity of limb paralysis. Twenty-one patients with acute stroke received a combination treatment of RPG-HAL and conventional rehabilitation. The feasibility and safety of RPG-HAL were evaluated based on changes in physical function and activities of daily living (ADL). RPG-HAL yielded improvement in gait speed, cadence, step length, and functional ambulation category (FAC). The effect size was >0.8 in all measurements. FAC (1.90) and Barthel Index (BI) (1.92) exhibited the highest scores. Twelve out of 14 patients with FAC 0 before RPG-HAL reached the upper FAC. Thus, earlier intervention using RPG-HAL as improving physical function, ADL, and gait ability in patients with stroke.

The Metabolic Cost of Exercising With a Robotic Exoskeleton: A Comparison of Healthy and Neurologically Impaired People

While neuro-recovery is maximized through active engagement, it has been suggested that the use of robotic exoskeletons in neuro-rehabilitation provides passive therapy. Using oxygen consumption (VO₂) as an indicator of energy expenditure, we investigated the metabolic requirements of completing exercises in a free-standing robotic exoskeleton, with 20 healthy and 12 neurologically impaired participants (six with stroke, and six with multiple sclerosis (MS)). Neurological participants were evaluated pre- and post- 12 weeks of twice weekly robotic therapy. Healthy participants were evaluated in, and out of, the exoskeleton. Both groups increased their VO₂ level from baseline during exoskeleton-assisted exercise (Healthy: mean change in VO₂ = 2.10 ± 1.61 ml/kg/min, p =< 0.001; Neurological: 1.38 ± 1.22, p = 0.002), with a lower predicted mean in the neurological sample (-1.08, 95%CI -2.02, -0.14, p = 0.02). Healthy participants exercised harder out of the exoskeleton than in it (difference in VO₂ = 3.50, 95%CI 2.62, 4.38, p =< 0.001). There was no difference in neurological participants' predicted mean VO₂ pre- and post- 12 weeks of robotic therapy 0.45, 95%CI -0.20, 1.11, p = 0.15), although subgroup analysis revealed a greater change after 12 weeks of robotic therapy in those with stroke (MS: -0.06, 95%CI -0.78, 0.66, p = 0.85; stroke: 1.00, 95%CI 0.3, 1.69, p = 0.01; difference = 1.06, p = 0.04). Exercise in a free-standing robotic exoskeleton is not passive in healthy or neurologically impaired people, and those with stroke may derive more benefit than those with MS.

A biomechanical comparison of powered robotic exoskeleton gait with normal and slow walking: An investigation with able-bodied individuals

BACKGROUND

Overground lower-limb robotic exoskeletons are assistive devices used to facilitate ambulation and gait rehabilitation. Our understanding of how closely they resemble comfortable and slow walking is limited. This information is important to maximise the effects of gait rehabilitation. The aim was to compare the 3D gait parameters of able-bodied individuals walking with and without an exoskeleton at two speeds (self-selected comfortable vs. slow, speed-matched to the exoskeleton) to understand how the user's body moved within the device.

METHODS

Eight healthy, able-bodied individuals walked along a 12-m walkway with and without the exoskeleton. Three-dimensional whole-body kinematics inside the device were captured. Temporal-spatial parameters and sagittal joint kinematics were determined for normal and exoskeleton walking. One-way repeated measures ANOVAs and statistical parametric mapping were used to compare the three walking conditions (P < .05).

FINDINGS

The walking speeds of the slow (0.44[0.03] m/s) and exoskeleton (0.41[0.03] m/s) conditions were significantly slower than the comfortable walking speed (1.54[0.07] m/s). However, time in swing was significantly greater (P < .001, d = -3.64) and double support was correspondingly lower (P < .001, d = 3.72) during exoskeleton gait than slow walking, more closely resembling comfortable speed walking. Ankle and knee angles were significantly reduced in the slow and exoskeleton conditions. Angles were also significantly different for the upper body.

INTERPRETATION

Although the slow condition was speed-matched to exoskeleton gait, the stance:swing ratio of exoskeleton stepping more closely resembled comfortable gait than slow gait. The altered upper body kinematics suggested that overground exoskeletons may provide a training environment that would also benefit balance training.

Robot-assisted Gait Training Using Welwalk in Hemiparetic Stroke Patients: An Effectiveness Study with Matched Control

OBJECTIVE

Although studies on the efficacy of the rehabilitation robot are increasing, there are few reports using the robot for gait training in the actual clinical setting. This study aimed to investigate the effectiveness of gait training using Welwalk in hemiparetic stroke patients in a real clinical setting.

MATERIALS AND METHODS

This prospective study included 36 hemiparetic stroke patients who underwent gait training using Welwalk. We examined the walking ability improvement efficiency using Functional Independence Measure (FIM)-walk as the primary outcome, which was compared with that of 36 patients (matched control group) who underwent conventional rehabilitation. Other outcomes were the actual gait training period using Welwalk, raw FIM-walk score, lower extremity motor functions score in Stroke Impairment Assessment Set at discharge, and duration from stroke onset until discharge.

RESULTS

The improvement efficiency of the FIM-walk was significantly higher in the Welwalk group than in the matched control group (control 0.48 ± 0.31, Welwalk 0.80 ± 0.38, p-value < 0.001). The mean gait training period using Welwalk was 5 weeks. No significant differences were found in other outcomes between the Welwalk group and the matched control group.

CONCLUSION

This study demonstrated the effectiveness of gait training using Welwalk on the improvement efficiency of the FIM-walk in hemiparetic stroke patients in an actual clinical setting.

Gait Adaptation Using a Cable-Driven Active Leg Exoskeleton (C-ALEX) With Post-Stroke Participants

Individuals with chronic hemiparesis post-stroke exhibit gait impairments that require functional rehabilitation through training. Exoskeletal robotic assistive devices can provide a user with continuous assistance but impose movement restrictions. There are currently devices that allow unrestricted movement but provide assistance only intermittently at specific points of the gait cycle. Our design, a cable-driven active leg exoskeleton (C-ALEX), allows the user both unrestricted movement and continuous force assistance throughout the gait cycle to assist the user in new walking patterns. In this study, we assessed the ability of C-ALEX to induce a change in the walking patterns of ten post-stroke participants using a single-session training protocol. The ability of C-ALEX to accurately provide forces and torques in the desired directions was also evaluated to compare its design performance to traditional rigid-link designs. Participants were able to reach 91% ± 12% of their target step length and 89% ± 13% of their target step height. The achieved step parameters differed significantly from participant baselines ( ). To quantify the performance, the forces in each cable's out of the plane movements were evaluated relative to the in-plane desired cable tension magnitudes. This corresponded to an error of under 2Nm in the desired controlled joint torques. This error magnitude is low compared to the system command torques and typical adult biological torques during walking (2-4%). These results point to the utility of using non-restrictive cable-driven architectures in gait retraining, in which future focus can be on rehabilitating gait pathologies seen in stroke survivors.

Effects of innovative hip-knee-ankle interlimb coordinated robot training on ambulation, cardiopulmonary function, depression, and fall confidence in acute hemiplegia

BACKGROUND

While Walkbot-assisted locomotor training (WLT) provided ample evidence on balance and gait improvements, the therapeutic effects on cardiopulmonary and psychological elements as well as fall confidence are unknown in stroke survivors.

OBJECTIVE

The present study aimed to compare the effects of Walkbot locomotor training (WLT) with conventional locomotor training (CLT) on balance and gait, cardiopulmonary and psychological functions and fall confidence in acute hemiparetic stroke.

METHODS

Fourteen patients with acute hemiparetic stroke were randomized into either the WLT (60 min physical therapy + 30 min Walkbot-assisted gait training) or CLT (60 min physical therapy + 30 min gait training) groups, 7 days/week over 2 weeks. Clinical outcomes included the Berg Balance Scale (BBS), Functional Ambulation Category (FAC), heart rate (HR), Borg Rating of Perceived Exertion (BRPE), Beck Depression Inventory-II (BDI-II), and the activities-specific balance confidence (ABC) scale. The analysis of covariance (ANCOVA) was conducted at P < 0.05.

RESULTS

ANCOVA showed that WLT showed superior effects, compared to CLT, on FAC, HR, BRPE, BDI-II, and ABC scale (P < 0.05), but not on BBS (P = 0.061).

CONCLUSIONS

Our results provide novel, promising clinical evidence that WLT improved balance and gait function as well as cardiopulmonary and psychological functions, and fall confidence in acute stroke survivors who were unable to ambulate independently.

[Modern aspects of the pathophysiology of walking disorders and their rehabilitation in post-stroke patients]

The problem of rehabilitation of post-stroke patients with motor deficit remains relevant with growing prevalence of disability and decreasing mortality, despite all measures aimed at stroke prevention and morbidity reduction. One of the most common consequences of stroke is gait impairment as a result of spastic paresis of the lower limb (decreased gait velocity, shortened step, excessive loading of intact limb etc.), which leads to significant maladaptation, increased risk of falls, decrease in quality of life. The article presents a detailed review of motor action in normal and pathologic conditions, analysis of neuronal structures involved into a movement act in healthy individuals and in stroke patients, current aspects of gait pathophysiology, characteristics of post-stroke gait (speed and asymmetry of gain, balance control impairment). A separate paragraph is devoted to gait recovery after stroke with analysis of existing and developing strategies of rehabilitation, aimed at the improvement of vertical posture, balance control and movement, condition, tone and functioning of skeletal muscles. Authors also analyze new research information on the efficacy of botulinum toxin preparations and programs of Guided Self-Rehabilitation Contracts (GSC), present the results of clinical trials demonstrating the efficacy of combination of these two methods.

A Review of Robot-Assisted Lower-Limb Stroke Therapy: Unexplored Paths and Future Directions in Gait Rehabilitation

Stroke affects one out of every six people on Earth. Approximately 90% of stroke survivors have some functional disability with mobility being a major impairment, which not only affects important daily activities but also increases the likelihood of falling. Originally intended to supplement traditional post-stroke gait rehabilitation, robotic systems have gained remarkable attention in recent years as a tool to decrease the strain on physical therapists while increasing the precision and repeatability of the therapy. While some of the current methods for robot-assisted rehabilitation have had many positive and promising outcomes, there is moderate evidence of improvement in walking and motor recovery using robotic devices compared to traditional practice. In order to better understand how and where robot-assisted rehabilitation has been effective, it is imperative to identify the main schools of thought that have prevailed. This review intends to observe those perspectives through three different lenses: the goal and type of interaction, the physical implementation, and the sensorimotor pathways targeted by robotic devices. The ways that researchers approach the problem of restoring gait function are grouped together in an intuitive way. Seeing robot-assisted rehabilitation in this unique light can naturally provoke the development of new directions to potentially fill the current research gaps and eventually discover more effective ways to provide therapy. In particular, the idea of utilizing the human inter-limb coordination mechanisms is brought up as an especially promising area for rehabilitation and is extensively discussed.

A randomized controlled study incorporating an electromechanical gait machine, the Hybrid Assistive Limb, in gait training of patients with severe limitations in walking in the subacute phase after stroke

Early onset, intensive and repetitive, gait training may improve outcome after stroke but for patients with severe limitations in walking, rehabilitation is a challenge. The Hybrid Assistive Limb (HAL) is a gait machine that captures voluntary actions and support gait motions. Previous studies of HAL indicate beneficial effects on walking, but these results need to be confirmed in blinded, randomized controlled studies. This study aimed to explore effects of incorporating gait training with HAL as part of an inpatient rehabilitation program after stroke. Thirty-two subacute stroke patients with severe limitations in walking were randomized to incorporated HAL training (4 days/week for 4 weeks) or conventional gait training only. Blinded assessments were carried out at baseline, after the intervention, and at 6 months post stroke. The primary outcome was walking independence according to the Functional Ambulation Categories. Secondary outcomes were the Fugl-Meyer Assessment, 2-Minute Walk Test, Berg Balance Scale, and the Barthel Index. No significant between-group differences were found regarding any primary or secondary outcomes. At 6 months, two thirds of all patients were independent in walking. Prediction of independent walking at 6 months was not influenced by treatment group, but by age (OR 0.848, CI 0.719-0.998, p = 0.048). This study found no difference between groups for any outcomes despite the extra resources required for the HAL training, but highlights the substantial improvements in walking seen when evidence-based rehabilitation is provided to patients, with severe limitations in walking in the subacute stage after stroke. In future studies potential subgroups of patients who will benefit the most from electromechanically-assisted gait training should be explored.

Single-stride exposure to pulse torque assistance provided by a robotic exoskeleton at the hip and knee joints

Robot assisted gait retraining is an increasingly common method for supporting restoration of walking function after neurological injury. Gait speed, an indicator of walking function, is correlated with propulsive force, a measure modulated by the posture of the trailing limb at push-off. With the ultimate goal of improving efficacy of robot assisted gait retraining, we sought to directly target gait propulsion, by exposing subjects to pulses of joint torque applied at the hip and knee joints to modulate push-off posture. In this work, we utilized a robotic exoskeleton to apply pulses of torque to the hip and knee joints, during individual strides, of 16 healthy control subjects, and quantified the effects of this intervention on hip extension and propulsive impulse during and after application of these pulses. We observed significant effects in the outcome measures primarily at the stride of pulse application and generally no after effects in the following strides. Specifically, when pulses were applied at late stance, we observed a significant increase in propulsive impulse when knee and/or hip flexion pulses were applied and a significant increase in hip extension angle when hip extension torque pulses were applied. When pulses were applied at early stance, we observed a significant increase in propulsive impulse associated with hip extension torque.

Robotic orthoses for gait rehabilitation: An overview of mechanical design and control strategies

The application of robotic devices in providing physiotherapies to post-stroke patients and people suffering from incomplete spinal cord injuries is rapidly expanding. It is crucial to provide valid rehabilitation for people who are experiencing abnormality in their gait performance; therefore, design and development of newer robotic devices for the purpose of facilitating patients' recovery is being actively researched. In order to advance the traditional gait treatment among patients, exoskeletons and orthoses were introduced over the last two decades. This article presents a thorough review of existing robotic gait rehabilitation devices. The latest advancements in the mechanical design, types of control and actuation are also covered. The study comprehends discussions on robotic rehabilitation devices developed both for the training on treadmill and over-ground training. The assist-as-needed strategy for the gait training is particularly emphasized while reviewing various control strategies applied to these robotic devices. This study further reviews experimental investigations and clinical assessments of different control strategies and mechanism designs of robotic gait rehabilitation devices using experimental and clinical trials.

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.

Measurement and Analysis of Gait Pattern during Stair Walk for Improvement of Robotic Locomotion Rehabilitation System

Background

Robotic locomotion rehabilitation systems have been used for gait training in patients who have had a stroke. Most commercialized systems allow patients to perform simple exercises such as balancing or level walking, but an additional function such as stair-walk training is required to provide a wide range of recovery cycle rehabilitation. In this study, we analyzed stair-gait patterns and applied the result to a robotic rehabilitation system that can provide a vertical motion of footplates.

Methods

To obtain applicable data for the robotic system with vertically movable footplates, stair-walk action was measured using an optical marker-based motion capture system. The spatial position data of joints during stair walking was obtained from six healthy adults who participated in the experiment. The measured marker data were converted into joint kinematic data by using an algorithm that included resampling and normalization. The spatial position data are represented as angular trajectories and the relative displacement of each joint on the anatomical sagittal plane and movements of hip joints on the anatomical transverse plane.

Results

The average range of motion (ROM) of each joint was estimated as (−6.75°, 48.69°) at the hip, (8.20°, 93.78°) at the knee, and (−17.78°, 11.75°) at the ankle during ascent and as (6.41°, 31.67°) at the hip, (7.38°, 91.93°) at the knee, and (−24.89°, 24.18°) at the ankle during descent. Additionally, we attempted to create a more natural stair-gait pattern by analyzing the movement of the hip on the anatomical transverse plane. The hip movements were estimated to within ±1.57 cm and ±2.00 cm for hip translation and to within ±2.52° and ±2.70° for hip rotation during stair ascent and stair descent, respectively.

Conclusions

Based on the results, standard patterns of stair ascent and stair descent were derived and applied to a lower-limb rehabilitation robot with vertically movable footplates. The relative trajectory from the experiment ascertained that the function of stair walking in the robotic system properly worked within a normal ROM.

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.

Prediction Method of Walking Speed at Swing Phase using Soleus Electromyogram Signal at Previous Stance Phase

A recent research has proposed a prediction method of walking speed with soleus electromyogram (EMG) signal activation level at push-off phase. However, the prediction of walking speed at low speed is inaccurate and the coefficients of determination (R² values) of the used linear regression model is low. In this study, we propose a new method for predicting walking speed during swing phase with soleus EMG signal activation levels at pre-load and push-off phases, and square root value is used as a feature. The proposed method is verified by walking experiment with 5 nondisabled subjects. (R² values) of the new method is improved by 10.3 % than that of the method used in the previous study. And the proposed method improves accuracy mainly at low speed and precision at high speed to predict a correct walking speed throughout walking speed range. Thus, the proposed method enhances the performance of the prediction model of walking speed without being biased in the range of high or low speed. The proposed method has potential to be used to control the gait speed of a lower-limb exoskeleton according to wearer's gait intention.

Factors That Contribute to the Use of Stroke Self-Rehabilitation Technologies: A Review

Background

Stroke is increasingly one of the main causes of impairment and disability. Contextual and empirical evidence demonstrate that, mainly due to service delivery constraints, but also due to a move toward personalized health care in the comfort of patients’ homes, more stroke survivors undergo rehabilitation at home with minimal or no supervision. Due to this trend toward telerehabilitation, systems for stroke patient self-rehabilitation have become increasingly popular, with many solutions recently proposed based on technological advances in sensing, machine learning, and visualization. However, by targeting generic patient profiles, these systems often do not provide adequate rehabilitation service, as they are not tailored to specific patients’ needs.

Objective

Our objective was to review state-of-the-art home rehabilitation systems and discuss their effectiveness from a patient-centric perspective. We aimed to analyze engagement enhancement of self-rehabilitation systems, as well as motivation, to identify the challenges in technology uptake.

Methods

We performed a systematic literature search with 307,550 results. Then, through a narrative review, we selected 96 sources of existing home rehabilitation systems and we conducted a critical analysis. Based on the critical analysis, we formulated new criteria to be used when designing future solutions, addressing the need for increased patient involvement and individualism. We categorized the criteria based on (1) motivation, (2) acceptance, and (3) technological aspects affecting the incorporation of the technology in practice. We categorized all reviewed systems based on whether they successfully met each of the proposed criteria.

Results

The criteria we identified were nonintrusive, nonwearable, motivation and engagement enhancing, individualized, supporting daily activities, cost-effective, simple, and transferable. We also examined the motivation method, suitability for elderly patients, and intended use as supplementary criteria. Through the detailed literature review and comparative analysis, we found no system reported in the literature that addressed all the set criteria. Most systems successfully addressed a subset of the criteria, but none successfully addressed all set goals of the ideal self-rehabilitation system for home use.

Conclusions

We identified a gap in the state-of-the-art in telerehabilitation and propose a set of criteria for a novel patient-centric system to enhance patient engagement and motivation and deliver better self-rehabilitation commitment.

A review of cable-driven rehabilitation devices

Purpose: To conduct a survey on the research and development of cable-driven rehabilitation devices (CDRDs). Method: This review searches in the databases of PubMed, IEEE Xplore Digital Library, Science Direct, and Google Scholar using various combinations of the following keywords: cable, wire, rehabilitation, assistance, therapy, training, robot, elastic, and pneumatic. Searches in the above databases for references cited by the above-searched references are also conducted to include a larger context of CDRDs. Results: CDRDs are classified into four categories, namely, serial exoskeleton-based, parallel exoskeleton-based, serial end-effector-based, and parallel end-effector-based CDRDs. Each category of CDRDs are further grouped based on the part of the human body to be rehabilitated. All four categories of CDRDs are examined and compared and their advantages and shortcomings are discussed based on popular rehabilitation requirements on weight, adaptability, versatility, misalignment, and safety. Open issues of CDRDs are also discussed.Conclusions: Each category of CDRDs has its own advantages and shortcomings. The selection of a CDRD highly depends on the specific application. Regarding the convenience of setting up a CDRD for rehabilitation, parallel CDRDs usually have better adaptability than serial ones. However, uncertainties come with parallel CDRDs, which makes the control of parallel CDRDs more challenging. Moreover, the strategy of inherent safety has a great potential to further improve the safety of CDRDs.Implications for rehabilitationCDRDs (and general RRDs) can deliver high-intensity training while therapists usually cannot. With up-to-date human-robot interaction techniques (e.g., virtual reality), CDRDs are more interesting and motivating to trainees than conventional manual rehabilitation therapies. CDRDs also provide financial benefits in the long-run. Currently existing RRDs available for clinical practice are mainly designed for the rehabilitation of shoulders, elbows, and knees. Parallel exoskeleton-based CDRDs can also be used for the rehabilitation of many other parts of trainees. Thus, CDRDs extend the coverage of RRDs in rehabilitation. Owing to their simple structures and light weights, CDRDs can be portable and used for rehabilitation at home. In this way, CDRDs can improve the duration and intensity of rehabilitation for those with limited access to rehabilitation institutes. As well known, the higher intensity of training leads to a higher rate of recovery.

Development of KIINCE: A kinetic feedback-based robotic environment for study of neuromuscular coordination and rehabilitation of human standing and walking

Introduction

The objective of this article is to introduce the robotic platform KIINCE and its emphasis on the potential of kinetic objectives for studying and training human walking and standing. The device is motivated by the need to characterize and train lower limb muscle coordination to address balance deficits in impaired walking and standing.

Methods

The device measures the forces between the user and his or her environment, particularly the force of the ground on the feet (F) that reflects lower limb joint torque coordination. In an environment that allows for exploration of the user’s capabilities, various forms of real-time feedback guide neural training to produce F appropriate for remaining upright. Control of the foot plate motion is configurable and may be user driven or prescribed. Design choices are motivated from theory of motor control and learning as well as empirical observations of F during walking and standing.

Results

Preliminary studies of impaired individuals demonstrate the feasibility and potential utility of patient interaction with kinetic immersive interface for neuromuscular coordination enhancement.

Conclusion

Applications include study and rehabilitation of standing and walking after injury, amputation, and neurological insult, with an initial focus on stroke discussed here.