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

Development and Validation of the Novel Exergame-Integrated Robotic Stepper Device for Seated Lower Limb Rehabilitation

Seated rehabilitation is essential in early-stage recovery for patients who can sit but cannot stand or walk. Robotic-based lower limb rehabilitation provides precise, task-specific training for recovery, but its application in seated exercises remains limited, creating a significant gap in early-stage rehabilitation. This study presents a novel exergame-integrated robotic stepper for seated bilateral and multi-joint lower limb rehabilitation. Twenty healthy participants performed seated stepping exercises across eight modes: passive (G0), three-level assistive(G1-G3), active (G4), and three-level resistive (G5-G7). Results demonstrated a strong correlation between the stepper's tilt angle and the ankle, knee, and hip joints. The device maintained consistent ROM for these joints across all modes, ensuring reliable joint engagement regardless of resistance or assistance levels. Weight shift increased progressively from passive (G0) to high resistance (G7), with higher shifts observed as assistance decreased and resistance increased. In assistive modes, a significant increase of 47.16% in weight shift was observed at low assistance (G3) (p <0.0167). In resistive modes, weight shift increased significantly by 86.08% in medium resistance (G6) and by 129.7% at high resistance (G7) (p <0.0167). Muscle activation significantly increased progressively from passive (G0) to high resistance (G7), with greater activations observed as assistance levels decreased and resistance levels increased (p <0.0083). These findings indicate that robotic stepper can be a versatile tool in progressive stroke rehabilitation, effectively adapting to different rehabilitation needs, from early-stage support to muscle strengthening.

Biomechanical characteristics and neuromuscular action control mechanism of single-dual-task walking-conversion training in stroke patients

Background and purposeThis study aimed to explore the biomechanical characteristics of patients with stroke and neuromuscular action control mechanisms in single-dual-task walking-conversion training.Materials and methodsPatients with stroke from four centers were enrolled and randomly divided into the cognitive combined treadmill-walking and exercise combined treadmill-walking groups (n = 30 per group). The gait spatiotemporal parameters, walking function, and fall risk of the two experimental groups were compared before and after 4 and 6 weeks of training. Surface electromyography (sEMG) and functional near-infrared spectroscopy (fNIRS) were performed to analyze neuromuscular action control mechanisms in different task phases.ResultsAfter 6 weeks of training, the gait spatiotemporal parameters, walking function, integral electromyogram (iEMG) values, and root mean square (RMS) of the affected lower limb muscles of the two experimental groups significantly improved (P < 0.01), while the fall risk was reduced (P < 0.01). fNIRS analysis showed that in both the single- and dual-task phases, HbO signal concentrations in the brain functional regions of the two experimental groups significantly increased after training (P < 0.01). These indicators were not significantly different between the two experimental groups after 6 weeks of training (P > 0.05). In addition, during the dual-task phase, the blood oxygen signal concentrations and functional connectivity in the functional brain regions of the two experimental groups were lower than those of healthy controls.ConclusionCognitive or motor tasks combined with treadmill-walking training can promote the recovery of physical function in patients with stroke.Clinical trial registration: This study was registered in the Chinese Clinical Trial Registry (ChiCTR; registration number: ChiCTR2200060864).

Clinicians' Perceptions and Potential Applications of Robotics for Task Automation in Critical Care: Qualitative Study

BACKGROUND

Interest in integrating robotics within intensive care units (ICUs) has been propelled by technological advancements, workforce challenges, and heightened clinical demands, including during the COVID-19 pandemic. The integration of robotics in ICUs could potentially enhance patient care and operational efficiency amid existing challenges faced by health care professionals, including high workload and decision-making complexities.

OBJECTIVE

This qualitative study aimed to explore ICU clinicians' perceptions of robotic technology and to identify the types of tasks that might benefit from robotic assistance. We focused on the degree of acceptance, perceived challenges, and potential applications for improving patient care in 5 Southeastern US hospitals between January and August 2023.

METHODS

A qualitative study through semistructured interviews and questionnaires was conducted with 15 ICU clinicians (7 nurses, 6 physicians, and 2 advanced practice providers) from 5 hospitals in the Southeast United States. Directed content analysis was used to categorize and interpret participants' statements, with statistical tests used to examine any role-based differences in how they viewed robotic integration.

RESULTS

Among the 15 participants, 73% (11/15) were female, with an average of 6.4 (SD 6.3) years of ICU experience. We identified 78 distinct tasks potentially suitable for robotic assistance, of which 50 (64%) involved direct patient care (eg, repositioning patients and assisting with simple procedures), 19 (24%) concerned indirect patient care (eg, delivering supplies and cleaning), 6 (8%) addressed administrative tasks (eg, answering call lights), and 3 (4%) were classified as mixed direct and indirect (eg, sitting with a patient to keep them calm). Most participants supported the automation of routine, noncritical tasks (eg, responding to nurse calls and measuring glucose levels), viewing this strategy as a way to alleviate workload and enhance efficiency. Conversely, high-complexity tasks requiring nuanced clinical judgment (eg, ventilator settings) were deemed unsuitable for full automation. Statistical analysis revealed no significant difference in how nurses, physicians, and advanced practice providers perceived these tasks (P=.22).

CONCLUSIONS

Our findings indicate a significant opportunity to use robotic systems to perform noncomplex tasks in ICUs, thereby potentially improving efficiency and reducing staff burden. Clinicians largely view robots as supportive tools rather than substitutes for human expertise. However, concerns persist regarding privacy, patient safety, and the loss of human touch, particularly for tasks requiring high-level clinical decision-making. Future research should involve broader, more diverse clinician samples and investigate the long-term impact of robotic assistance on patient outcomes while also incorporating patient perspectives to ensure ethical, patient-centered adoption of robotic technology.

Effect and optimal exercise prescription of robot-assisted gait training on lower extremity motor function in stroke patients: a network meta-analysis

OBJECTIVE

This study aimed to evaluate the effectiveness of robot-assisted gait training (RAGT) and explore the optimal exercise prescription using a network meta-analysis approach.

DATA SOURCES

A comprehensive search was conducted on randomized controlled trials comparing robotic and conventional rehabilitation published up to January 2024 in PubMed, Web of Science, Cochrane Library, Embase, CNKI, VIP, Wanfang, and SinoMed databases.

REVIEW METHODS

The evaluation parameters included Fugl-Meyer Assessment of Lower Extremity (FMA-LE), Functional Ambulation Category (FAC), Berg Balance Scale (BBS), and 6-Minute Walk Test (6MWT). Two investigators independently performed study screening, data extraction, and bias evaluation. Data were merged, analyzed, and plotted using Review Manager 5.4.1 and Stata 18.0 software.

RESULTS

A total of 21 articles involving 822 subjects were included in the analysis. RAGT positively influenced FMA-LE score (MD = 3.74, 95%CI 3.02-4.46, P < 0.05), FAC score (MD = 0.31, 95%CI 0.1-0.53, P < 0.05), BBS score (MD = 3.63, 95%CI 2.46-4.80, P < 0.05), and 6MWT score (MD = 23.73, 95%CI 15.31-32.14, P < 0.05). Surface under the cumulative ranking curve (SUCRA) values indicated that an exercise time of 40-60 min/training (97.4%), exercise frequency of 2-5 times/week (87.6%), and exercise duration of 8-12 weeks (78.1%) were most effective in improving the FMA-LE score.

CONCLUSIONS

RAGT can effectively improve lower limb motor function, walking function, balance function, and walking endurance in stroke patients. For optimal improvement in FMA-LE score, an exercise time of 40-60 min/training, exercise frequency of 2-5 times/week, and exercise duration of 8-12 weeks are recommended.

Effect of using home-based dynamic intermittent pneumatic compression therapy during periods of physical activity on functional and vascular health outcomes in chronic stroke: A randomized controlled clinical trial

BACKGROUND

Intermittent pneumatic compression (IPC) therapy may benefit stroke patients by eliciting more intensive training sessions that may result in better health, mobility and ultimately quality of life. The purpose of this randomized controlled trial was to assess the effect of using a home-based IPC device on functional outcomes and vascular health in individuals with chronic stroke.

METHODS

Thirty-one stroke survivors (64.3 ± 14.3y; 4.3 ± 2.7y since stroke) completed pre- and post-intervention assessments of functional capacity (six-minute walk test [6MWT], timed-up-and-go, 10m walk test), vascular health (pulse wave analysis, carotid-femoral pulse wave velocity), and physical activity. Following the pre-assessment, individuals were randomly assigned to either a daily, 12-week, home-based IPC group, or to a usual care control (CON) group. Outcomes were assessed using analysis of covariance (ANCOVA), controlling for age and any baseline differences.

RESULTS

Following ANCOVA, a significant increase in 6MWT walking distance was observed post-assessment for the IPC (Mean ±  SD [95%CI]; 188 ±  19 m [177-199m]) but not the CON group (167 ±  19 m [157-178m]) (p <  0.05). A significant reduction in peripheral systolic blood pressure was reported at the post-assessment for the IPC group (136.2 ±  8.0 mmHg [131.9-140.4 mmHg]) but not for CON (142.2 ±  8.0 mmHg [138.1-144.6 mmHg]) (p <  0.05). Similar findings were observed for central systolic blood pressure. Physical activity levels significantly increased at the post-assessment for IPC (1857 ±  879 MET·min-1·week-1 [1390-2325 MET·min-1·week-1]) but not for the CON group (1161 ± 879 MET·min-1·week-1 [677-1645 MET·min-1·week-1]), while for time spent sitting, a significantly greater reduction was observed at the post-assessment for the IPC group (396 ±  86 mins [350-442 mins]) compared to CON (486 ± 86 mins [439-534 mins]) (both p <  0.05).

CONCLUSIONS

The observed improvements in functional mobility, cardiovascular health, increased physical activity and reduced sedentary time demonstrates important clinical implications of 'home-based' IPC therapy as a clinical training aid for stroke rehabilitation. Home-based IPC therapy could serve as an adjunct to conventional rehabilitation, however, further research is needed to determine whether IPC therapy can sustain or improve function over time for individuals in the chronic stage of recovery.

Kinematics, kinetics, and muscle activations during human locomotion over compliant terrains

Walking on compliant terrains, like carpets, grass, and soil, presents a unique challenge, especially for individuals with mobility impairments. In contrast to rigid-ground walking, compliant surfaces alter movement dynamics and increase the risk of falls. Understanding and modeling gait control across such soft and deformable surfaces is thus crucial for maintaining daily mobility. However, access to the necessary equipment for modeling compliant surface walking is limited. Therefore, in this paper, we present the first publicly available biomechanics dataset of 20 individuals walking on terrains of varying compliance, using a unique robotic device, the Variable Stiffness Treadmill 2 (VST 2), designed to simulate walking on adjustable compliant terrain. VST 2 provides a consistent and reproducible environment for studying the biomechanics of walking on such surfaces within laboratory settings. The goal of this dataset is to provide insights into the muscular, kinematic, and kinetic adaptations that occur when humans walk on compliant terrain in order to design better controllers for prosthetic limbs, improve rehabilitation protocols, and develop adaptive assistive devices that can enhance mobility on compliant surfaces.

Effect of a Multicomponent Exercise Intervention on Recovery of Walking Ability in Stroke Survivors: A Systematic Review With Meta-analysis

OBJECTIVE

To evaluate whether multicomponent exercise (MCE) is more effective than single exercise in improving walking ability in patients with stroke.

DESIGN

A systematic review and meta-analysis.

DATA SOURCES

A systematic search of PubMed, Embase, Web of Science, Cochrane Library, and CINAHL from the establishment of each database to February 2024 was performed. A combination of medical subject headings and free-text terms relating to stroke and exercise were searched.

STUDY SELECTION

Randomized controlled trials treating stroke survivors with MCE were included. The control groups received conventional treatments such as conventional treatment or no intervention or sham training; the experimental groups received MCE. The outcome measures were walking endurance, gait speed, and balance ability.

DATA EXTRACTION

The data extraction form was completed by 2 independent reviewers. The risk of bias was assessed using the Cochrane Risk of Bias Tool for randomized controlled trials. Review manager 5.4 software was used for data analysis. Subgroup analysis and sensitivity analysis were used to supplement the results with higher heterogeneity. The preferred reporting project for systematic reviews and meta-analyses 2020 guidelines were followed.

DATA SYNTHESIS

Twelve studies were included. Meta-analyses found that compared with the control group, the MCE significantly affected gait speed (mean difference=0.11; 95% CI, 0.06-0.16; I2=0%), but the effect on balance ability was not statistically significant. Subgroup analysis showed that MCE (≥60min) was effective in improving walking endurance. These results suggest that MCE improves walking endurance and walking speed in patients with stroke.

CONCLUSIONS

MCE helps improve the gait speed of stroke survivors. Prolonging the MCE time may have a better effect on improving the walking endurance of patients with stroke.

Comparing effects of wearable robot-assisted gait training on functional changes and neuroplasticity: A preliminary study

Robot-assisted gait training (RAGT) is a promising technique for improving the gait ability of elderly adults and patients with gait disorders by enabling high-intensive and task-specific training. Gait functions involve multiple brain regions and networks. Therefore, RAGT is expected to affect not just gait performance but also neuroplasticity and cognitive ability. The purpose of this preliminary study was to verify the feasibility of the proposed RAGT design and to assess and compare the effect sizes of various measurement variables, including physical, cognitive, and neuroimaging induced by RAGT. Twelve healthy adults without any neurological or musculoskeletal disorders participated in this study. All participants wore a wearable exoskeleton robot and underwent 10 RAGT sessions. Functional data related to physical and cognitive abilities and neuroimaging data obtained from a magnetic resonance imaging (MRI) scanner and a functional near-infrared spectroscopy (fNIRS) device were acquired before and after the training sessions to assess the effect sizes of variables affected by RAGT. All participants underwent 10 sessions of RAGT without any adverse incidents, and the feasibility of the proposed RAGT design, consisting of preferred speed walking, fast speed walking, inclined walking, and squats, was validated. Variables related to physical and cognitive abilities significantly improved, but those related to neuroplasticity did not. The effect size of physical ability was "very large," whereas that of cognitive ability was "medium-to-large." The effect sizes of functional and structural neuroplasticity showed "medium" and "very small," respectively. The effect size of the RAGT varied depending on the measured variables, with the effect size being the greatest for physical ability, followed by cognitive ability, functional neuroplasticity, and structural neuroplasticity. The proposed RAGT design affects cognitive and neuroplastic effects beyond the physical effect directly affected by RAGT. This study highlights that while RAGT can positively influence cognitive outcomes beyond physical benefits, more intensive interventions may be required to elicit significant neuroplastic changes. This preliminary study offers useful information for researchers interested in designing robot-assisted training by investigating the potential extent of neuroplastic effects. Trial registration: KCT0006738.

The Association of Interlimb Coordination and Temporal Symmetry With Walking Function and Motor Impairment After Stroke

OBJECTIVE

Interlimb coordination during walking is impaired after stroke, with unknown effects on walking function. This cross-sectional study determined associations of interlimb coordination and temporal symmetry with walking function and motor impairment.

DESIGN

During walking, participants wore wireless sensors to detect heel strikes. We calculated interlimb coordination as the phase coordination index and temporal symmetry as the ratio of contralesional (i.e., paretic) to ipsilesional (i.e., nonparetic) stance times. Associations with walking speed (10-meter walk test), walking endurance (6-min walk test), dynamic balance (Mini-Balance Evaluation Systems Test), and motor impairment (Fugl-Meyer Lower Extremity assessment) were assessed.

RESULTS

Fifty-six individuals with chronic stroke were tested. Worse interlimb coordination was correlated with slower comfortable ( R = -0.38, P = 0.004) and maximal ( R = -0.36, P = 0.006) walking speed and worse motor function ( R = -0.45, P = 0.001). Worse temporal symmetry was correlated with worse motor function ( R = 0.39, P = 0.004). Interlimb coordination had stronger associations than temporal symmetry with comfortable ( R = -0.38 vs. 0.08) and maximal walking speeds ( R = -0.36 vs. 0.12).

CONCLUSIONS

Poor interlimb coordination was associated with slow walking and motor impairment and had stronger associations with walking speeds than temporal symmetry did. Interlimb coordination may provide unique insights into walking function and a target for walking rehabilitation after stroke.

Real-Time Gait Intention Recognition for Active Control of Unilateral Knee Exoskeleton

Real-time gait estimation is important for the synchrony control of robotic exoskeleton to provide walking assistance. However, for stroke patients with hemiplegic paralysis, the gait pattern is very complex. Accurate and timely gait intention recognition is therefore difficult. To achieve human-robot synchrony control for an unilateral knee exoskeleton, a gait intention recognizer coupling the adaptive frequency oscillator (AFO) and back propagation neural networks (BPNN) is proposed in this paper. The BPNN is trained with gait data of healthy subjects and stroke patients to improve the accuracy of recognized gait pattern, which is then imported into flexible interaction module to provide appropriate assistance. To evaluate the performance of gait intention recognition, three stroke patients were recruited to conduct level ground walking tests. The kinematic and biomechanical data were captured in each test and processed for the evaluation. Experimental results demonstrate the effectiveness of gait intention recognition and movement assistance.

The efficacy of exoskeleton robotic training on ambulation recovery in patients with spinal cord injury: A meta-analysis

Objective: To discuss the efficacy of exoskeleton robotic training on ambulation recovery in patients with spinal cord injury (SCI).Methods: PubMed, Embase, and Cochrane Central Register of Controlled Trials were searched systematically from their inception to April 2022 for studies on exoskeleton robotic training in patients with SCI. The language was restricted to English. The retrieved studies were screened to select eligible clinical trials. Meta-analysis was performed using Review Manager 5.4.Results: Eleven randomized clinical trials (RCTs) involving 456 participants were included in the meta-analysis. The results of the meta-analysis showed that exoskeleton robotic training was more effective in improving FIM [SMD = 0.58, 95%CI = (0.07, 1.10), P = 0.03], LEMS [MD = 4.64, 95%CI = (3.58, 5.70), P<0.05], MAS [MD = 0.76, 95%CI = (0.48, 1.03), P<0.05] and BBS [MD = -3.11, 95%CI =  (-12.59, 6.36), P<0.05] in patients with SCI, compared to conventional gait training(CGT). Subgroup analysis showed that the exoskeleton robotic could significantly improve the walking endurance and walking speed of patients with a duration of injury within 6 months. The sensitivity of inverted funnel plot analysis is low, suggesting that the analysis results of this study are relatively stable.Conclusion: Exoskeleton robotic training improves ambulation in patients with SCI, especially for patients with a course of injury within six months.

Effectiveness of combined robotics and virtual reality on lower limb functional ability in stroke survivors: A systematic review of randomized controlled trials

Lower limb impairments are common consequences of stroke. Robotics and virtual reality (VR) play crucial roles in improving lower limb function post-stroke. This review aims to assess the effects of combined robot and VR interventions on lower limb functional ability poststroke and to provide recommendations for future studies in the rehabilitation field. PubMed, SCOPUS, CINAHL, MEDLINE, EMBASE, and Web of Science were searched from inception to March 1, 2024. Randomized controlled trials (RCTs) involving patients with a stroke, administering combined robot and VR compared with passive (i.e., rest) or active (any intervention), and including at least one outcome evaluating lower limb function (i.e., balance, gait, mobility, muscle tone, muscle strength, range of motion) or activities of daily living were selected. The Cochrane Collaboration tool was employed to evaluate the risk of bias in the included studies. Nine studies met the eligibility criteria. In total, 364 stroke survivors (Mean age 55.62 years) were involved in this review. According to the Cochrane Collaboration tool, five studies were classified as "high quality," "moderate quality" (n=3), and "low quality" (n=1). There are mixed findings on the effects of combined robot and VR on lower limb functional ability in stroke survivors. The evidence for the effects of combined robot and VR on lower limb functional ability post-stroke is promising. Further trials with long-term follow-up are strongly warranted to understand the immediate and long-term effect of combined robot and VR intervention on various lower limb impairments and to define the optimal treatment protocols.

Virtual Obstacle Avoidance Strategy: Navigating through a Complex Environment While Interacting with Virtual and Physical Elements

Robotic walking devices can be used for intensive exercises to enhance gait rehabilitation therapies. Mixed Reality (MR) techniques may improve engagement through immersive and interactive environments. This article introduces an MR-based multimodal human-robot interaction strategy designed to enable shared control with a Smart Walker. The MR system integrates virtual and physical sensors to (i) enhance safe navigation and (ii) facilitate intuitive mobility training in personalized virtual scenarios by using an interface with three elements: an arrow to indicate where to go, laser lines to indicate nearby obstacles, and an ellipse to show the activation zone. The multimodal interaction is context-based; the presence of nearby individuals and obstacles modulates the robot's behavior during navigation to simplify collision avoidance while allowing for proper social navigation. An experiment was conducted to evaluate the proposed strategy and the self-explanatory nature of the interface. The volunteers were divided into four groups, with each navigating under different conditions. Three evaluation methods were employed: task performance, self-assessment, and observational measurement. Analysis revealed that participants enjoyed the MR system and understood most of the interface elements without prior explanation. Regarding the interface, volunteers who did not receive any introductory explanation about the interface elements were mostly able to guess their purpose. Volunteers that interacted with the interface in the first session provided more correct answers. In future research, virtual elements will be integrated with the physical environment to enhance user safety during navigation, and the control strategy will be improved to consider both physical and virtual obstacles.

iP3T: an interpretable multimodal time-series model for enhanced gait phase prediction in wearable exoskeletons

Introduction

Wearable exoskeletons assist individuals with mobility impairments, enhancing their gait and quality of life. This study presents the iP3T model, designed to optimize gait phase prediction through the fusion of multimodal time-series data.

Methods

The iP3T model integrates data from stretch sensors, inertial measurement units (IMUs), and surface electromyography (sEMG) to capture comprehensive biomechanical and neuromuscular signals. The model's architecture leverages transformer-based attention mechanisms to prioritize crucial data points. A series of experiments were conducted on a treadmill with five participants to validate the model's performance.

Results

The iP3T model consistently outperformed traditional single-modality approaches. In the post-stance phase, the model achieved an RMSE of 1.073 and an R2 of 0.985. The integration of multimodal data enhanced prediction accuracy and reduced metabolic cost during assisted treadmill walking.

Discussion

The study highlights the critical role of each sensor type in providing a holistic understanding of the gait cycle. The attention mechanisms within the iP3T model contribute to its interpretability, allowing for effective optimization of sensor configurations and ultimately improving mobility and quality of life for individuals with gait impairments.

Sensing and Control Strategies Used in FES Systems Aimed at Assistance and Rehabilitation of Foot Drop: A Systematic Literature Review

Functional electrical stimulation (FES) is a rehabilitation and assistive technique used for stroke survivors. FES systems mainly consist of sensors, a control algorithm, and a stimulation unit. However, there is a critical need to reassess sensing and control techniques in FES systems to enhance their efficiency. This SLR was carried out following the PRISMA 2020 statement. Four databases (PubMed, Scopus, Web of Science, Wiley Online Library) from 2010 to 2024 were searched using terms related to sensing and control strategies in FES systems. A total of 322 articles were chosen in the first stage, while only 60 of them remained after the final filtering stage. This systematic review mainly focused on sensor techniques and control strategies to deliver FES. The most commonly used sensors reported were inertial measurement units (IMUs), 45% (27); biopotential electrodes, 36.7% (22); vision-based systems, 18.3% (11); and switches, 18.3% (11). The control strategy most reported is closed-loop; however, most of the current commercial FES systems employ open-loop strategies due to their simplicity. Three main factors were identified that should be considered when choosing a sensor for gait-oriented FES systems: wearability, accuracy, and affordability. We believe that the combination of computer vision systems with artificial intelligence-based control algorithms can contribute to the development of minimally invasive and personalized FES systems for the gait rehabilitation of patients with FDS.

Stroke rehabilitation: from diagnosis to therapy

Stroke remains a significant global health burden, necessitating comprehensive and innovative approaches in rehabilitation to optimize recovery outcomes. This paper provides a thorough exploration of rehabilitation strategies in stroke management, focusing on diagnostic methods, acute management, and diverse modalities encompassing physical, occupational, speech, and cognitive therapies. Emphasizing the importance of early identification of rehabilitation needs and leveraging technological advancements, including neurostimulation techniques and assistive technologies, this manuscript highlights the challenges and opportunities in stroke rehabilitation. Additionally, it discusses future directions, such as personalized rehabilitation approaches, neuroplasticity concepts, and advancements in assistive technologies, which hold promise in reshaping the landscape of stroke rehabilitation. By delineating these multifaceted aspects, this manuscript aims to provide insights and directions for optimizing stroke rehabilitation practices and enhancing the quality of life for stroke survivors.

Exoskeleton rehabilitation robot training for balance and lower limb function in sub-acute stroke patients: a pilot, randomized controlled trial

PURPOSE

This pilot study aimed to investigate the effects of REX exoskeleton rehabilitation robot training on the balance and lower limb function in patients with sub-acute stroke.

METHODS

This was a pilot, single-blind, randomized controlled trial. Twenty-four patients with sub-acute stroke (with the course of disease ranging from 3 weeks to 3 months) were randomized into two groups, including a robot group and a control group. Patients in control group received upright bed rehabilitation (n = 12) and those in robot group received exoskeleton rehabilitation robot training (n = 12). The frequency of training in both groups was once a day (60 min each) for 5 days a week for a total of 4 weeks. Besides, the two groups were evaluated before, 2 weeks after and 4 weeks after the intervention, respectively. The primary assessment index was the Berg Balance Scale (BBS), whereas the secondary assessment indexes included the Fugl-Meyer Lower Extremity Motor Function Scale (FMA-LE), the Posture Assessment Scale for Stroke Patients (PASS), the Activities of Daily Living Scale (Modified Barthel Index, MBI), the Tecnobody Balance Tester, and lower extremity muscle surface electromyography (sEMG).

RESULTS

The robot group showed significant improvements (P < 0.05) in the primary efficacy index BBS, as well as the secondary efficacy indexes PASS, FMA-LE, MBI, Tecnobody Balance Tester, and sEMG of the lower limb muscles. Besides, there were a significant differences in BBS, PASS, static eye-opening area or dynamic stability limit evaluation indexes between the robotic and control groups (P < 0.05).

CONCLUSIONS

This is the first study to investigate the effectiveness of the REX exoskeleton rehabilitation robot in the rehabilitation of patients with stroke. According to our results, the REX exoskeleton rehabilitation robot demonstrated superior potential efficacy in promoting the early recovery of balance and motor functions in patients with sub-acute stroke. Future large-scale randomized controlled studies and follow-up assessments are needed to validate the current findings.

CLINICAL TRIALS REGISTRATION

URL: https://www.chictr.org.cn/index.html.Unique identifier: ChiCTR2300068398.

Devices for Gait and Balance Rehabilitation: General Classification and a Narrative Review of End Effector-Based Manipulators

Gait and balance have a direct impact on patients’ independence and quality of life. Due to a higher life expectancy, the number of patients suffering neurological disorders has increased exponentially, with gait and balance impairments being the main side effects. In this context, the use of rehabilitation robotic devices arises as an effective and complementary tool to recover gait and balance functions. Among rehabilitation devices, end effectors present some advantages and have shown encouraging outcomes. The objective of this study is twofold: to propose a general classification of devices for gait and balance rehabilitation and to provide a review of the existing end effectors for such purposes. We classified the devices into five groups: treadmills, exoskeletons, patient-guided systems, perturbation platforms, and end effectors. Overall, 55 end effectors were identified in the literature, of which 16 were commercialized. We found a disproportionate number of end effectors capable of providing both types of rehabilitation (2/55) and those focused on either balance (21/55) or gait (32/55). The analysis of their features from a mechanical standpoint (degrees of freedom, topology, and training mode) allowed us to identify the potential of parallel manipulators as driving mechanisms of end effector devices and to suggest several future research directions.

Technological Advances in Stroke Rehabilitation: Robotics and Virtual Reality

Robotic technology and virtual reality (VR) have been widely studied technologies in stroke rehabilitation over the last few decades. Both technologies have typically been considered as ways to enhance recovery through promoting intensive, repetitive, and engaging therapies. In this review, we present the current evidence from interventional clinical trials that employ either robotics, VR, or a combination of both modalities to facilitate post-stroke recovery. Broadly speaking, both technologies have demonstrated some success in improving post-stroke outcomes and complementing conventional therapy. However, more high-quality, randomized, multicenter trials are required to confirm our current understanding of their role in precision stroke recovery.

Robot-assisted support combined with electrical stimulation for the lower extremity in stroke patients: a systematic review

Objective. The incidence of stroke rising, leading to an increased demand for rehabilitation services. Literature has consistently shown that early and intensive rehabilitation is beneficial for stroke patients. Robot-assisted devices have been extensively studied in this context, as they have the potential to increase the frequency of therapy sessions and thereby the intensity. Robot-assisted systems can be combined with electrical stimulation (ES) to further enhance muscle activation and patient compliance. The objective of this study was to review the effectiveness of ES combined with all types of robot-assisted technology for lower extremity rehabilitation in stroke patients.Approach. A thorough search of peer-reviewed articles was conducted. The quality of the included studies was assessed using a modified version of the Downs and Black checklist. Relevant information regarding the interventions, devices, study populations, and more was extracted from the selected articles.Main results. A total of 26 articles were included in the review, with 23 of them scoring at least fair on the methodological quality. The analyzed devices could be categorized into two main groups: cycling combined with ES and robots combined with ES. Overall, all the studies demonstrated improvements in body function and structure, as well as activity level, as per the International Classification of Functioning, Disability, and Health model. Half of the studies in this review showed superiority of training with the combination of robot and ES over robot training alone or over conventional treatment.Significance. The combination of robot-assisted technology with ES is gaining increasing interest in stroke rehabilitation. However, the studies identified in this review present challenges in terms of comparability due to variations in outcome measures and intervention protocols. Future research should focus on actively involving and engaging patients in executing movements and strive for standardization in outcome values and intervention protocols.

The effects of visual skills training on cognitive and executive functions in stroke patients: a systematic review with meta-analysis

The visual system and associated skills are of particular importance in stroke rehabilitation. The process of neuroplasticity involved in restoring cognitive function during this period is mainly based on anatomical and physiological mechanisms. However, there is little evidence-based knowledge about the effects of visual skills training that could be used to improve therapeutic outcomes in cognitive rehabilitation. A computerized systematic literature search was conducted in the PubMed, Medline, and Web of Science databases from 1 January 1960 to 11 Febuary 2024. 1,787 articles were identified, of which 24 articles were used for the calculation of weighted standardized mean differences (SMD) after screening and eligibility verification. The findings revealed moderate effects for global cognitive function (SMD = 0.62) and activities of daily living (SMD = 0.55) as well as small effects for executive function (SMD = 0.20) - all in favor of the intervention group. The analyses indicate that the results may not be entirely robust, and should therefore be treated with caution when applied in practice. Visual skills training shows positive effects in improving cognitive and executive functions, especially in combination with high cognitive load and in an early phase of rehabilitation. An improvement in activities of daily living can also be observed with this type of intervention. The high heterogeneity of the studies and different treatment conditions require the identification of a relationship between certain visual skills and executive functions in future research.

Concurrent ankle-assisted movement, biofeedback, and proprioceptive stimulation reduces lower limb motor impairment and improves gait in persons with stroke

BACKGROUND

Persons with stroke live with residual sensorimotor impairments in their lower limbs (LL), which affects their gait.

PURPOSE

We investigated whether these residual impairments and resulting gait deficits can be reduced through concurrently applied assisted movement, biofeedback, and proprioceptive stimulation.

METHODS

A robotic device provided impairment-oriented training to the affected LL of 24 persons with stroke (PwS) with moderate-to-severe LL impairment. Participants were given 22-30 training sessions over 2-3 months. During training, the interventional device cyclically dorsiflexed and plantarflexed the ankle at 5 deg/s through ±15 deg for 30 min while the participant assisted with the imposed movement. Concurrently, participants received visual biofeedback of assistive joint torque or agonist EMG while mechanical vibration was applied to the currently lengthening (i.e. antagonist) tendon.

RESULTS

Sensorimotor impairment significantly decreased over the training period, which was sustained over 3 months, based on the Fugl-Meyer Assessment (FMA-LL) (p < .001), modified Ashworth scale in dorsiflexors (p < .05), and an ankle strength test (dorsiflexors and plantarflexors) (p < .05). Balance and gait also improved, based on the Tinetti Performance Oriented Mobility Assessment (POMA) (p < .05).

CONCLUSION

Impairment-oriented training using a robotic device capable of applying assisted movement, biofeedback, and proprioceptive stimulation significantly reduces LL impairment and improves gait in moderately-to-severely impaired PwS.

ROBOT-ASSISTED TARGETED GAIT TRAINING

Background

Millions of people are affected yearly by "runner's knee" and osteoarthritis, which is thought to be related to impact force. Millions are also affected by chronic falling, who are usually both difficult to identify and train. While at first glance, these topics seem to be entirely disconnected, there appears to be a need for a device that would address both issues. This paper proposes and investigates the use of the Variable Stiffness Treadmill (VST) as a targeted training device for the different populations described above.

Materials and Methods

The VST is the authors' unique robotic split-belt treadmill that can reduce the vertical ground stiffness of the left belt, while the right belt remains rigid. In this work, heart rate and energy expenditure are measured for healthy subjects in the challenging asymmetric environment created by the VST and compared to a traditional treadmill setting.

Results

This study shows that this asymmetric environment results in an increase in heart rate and energy expenditure, an increase in activity in the muscles about the hip and knee, and a decrease in impact force at heel strike.

Conclusions

Compliant environments, like those created on the VST, may be a beneficial tool as they can: reduce high-impact forces during running and walking, significantly engage the muscles surrounding the hip and knee allowing for targeted training and rehabilitation, and assist in identifying and training high fall-risk individuals.

Effect of robot-assisted gait training on motor dysfunction in Parkinson's patients:A systematic review and meta-analysis

BACKGROUND

Robot-assisted gait training (RAGT) has been reported to treat motor dysfunction in patients with Parkinson's disease (PD) in the last few years. However, the benefits of RAGT for treating motor dysfunction in PD are still unclear.

OBJECTIVES

To investigate the efficacy of RAGT for motor dysfunction in PD patients.

METHODS

We searched PubMed, Web of Science, Cochrane Library, Embase, CNKI, Wanfang, Chinese Biomedical Literature Database (CBM), and Chinese VIP Database for randomized controlled trials investigating RAGT to improve motor dysfunction in PD from the databases' inception dates until September 1, 2022. The following outcome indexes were employed to evaluate motor dysfunction: the Berg Balance Scale (BBS), Activities-specific Balance Confidence Scale (ABC), 10-Meter Walk Test gait speed (10-MWT), gait speed, stride length, cadence Unified Parkinson Disease Rating Scale Part III (UPDRS III), 6-Minute Walk Test (6MWT), and the Timed Up and Go test (TUG). The meta-analysis was performed using the proper randomeffect model or fixed-effect model to evaluate the difference in efficacy between the RAGT and the control groups. The Cochrane Risk of Bias Tool was used for the included studies and Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) was used to interpret the certainty of the results.

RESULTS

The results consisted of 17 studies comprising a total of 670 participants. Six hundred and seven PD patients with motor dysfunction were included: 335 in the RAGT group and 335 in the control group. This meta-analysis results established that when compared with the control group, robot-assisted gait training improved the BBS results of PD patients (MD: 2.80, 95%CI: 2.11-3.49, P< 0.00001), ABC score (MD: 7.30, 95%CI: 5.08-9.52, P< 0.00001), 10-MWT (MD: 0.06, 95%CI: 0.03-0.10, P= 0.0009), gait speed (MD: 3.67, 95%CI: 2.58-4.76, P< 0.00001), stride length (MD: 5.53, 95%CI: 3.64-7.42, P< 0.00001), cadence (MD: 4.52, 95%CI: 0.94-8.10, P= 0.01), UPDRS III (MD: -2.16, 95%CI: -2.48--1.83, P< 0.00001), 6MWT (MD: 13.87, 95%CI: 11.92-15.82, P< 0.00001). However, RAGT did not significantly improve the TUG test result of patients with PD (MD =-0.56, 95% CI: -1.12-0.00, P= 0.05). No safety concerns or adverse reactions among robot-assisted gait training patients were observed.

CONCLUSION

Even though RAGT can improve balance function, walking function, and gait performance and has demonstrated positive results in several studies, there is currently insufficient compelling evidence to suggest that it can improve all aspects of lower motor function.

Effects of robot-assisted walking training on balance, motor function, and ADL depending on severity levels in stroke patients

BACKGROUND

Despite the explosive increase in interest regarding Robot-Assisted Walking Training (RAWT) for stroke patients, very few studies have divided groups according to the severity levels of patients and conducted studies on the effects of RAWT.

OBJECTIVE

The purpose of this study was to present a definite basis for physical therapy using the robot-assisted walking device through a more detailed comparison and analysis and to select the optimal target of RAWT.

METHODS

This study was designed as a prospective and randomized controlled trial to investigate the effect of RAWT on balance, motor function, and Activities of Daily Living (ADL) depending on severity levels in stroke patients. 100 participants were randomly divided into study and control groups in equal numbers. The study group was 49 and the control group was 47. One from the study group and three from the control group were eliminated. The study period is four weeks in total, and RAWT is performed five times a week for 40 minutes only for study group. During the same period, all group members had 30 minutes of Conventional Physiotherapy (CP) five times a week.

RESULTS

The results of this study clearly confirmed that RAWT combined with CP produces more significant improvement in patients with stroke than the CP alone. And they indicated that RAWT had a more considerable effect in the poor or fair trunk control group for trunk balance and in the high fall risk group for balance. In motor function, RAWT showed its value in the severe and marked motor impairment group. The total or severe dependence group in ADL experienced more improvements for RAWT.

CONCLUSION

This study can be concluded that the lower the level of physical functions, the more effective it responds to RAWT. As demonstrated in the results of this study, the potential of current robotic technology appears to be greatest at very low functional levels of stroke patients. Patients with low functional levels among stroke patients may benefit from robot rehabilitation.

The effect of the Lokomat® robotic-orthosis system on lower extremity rehabilitation in patients with stroke: a systematic review and meta-analysis

Background

The Lokomat® is a device utilized for gait training in post-stroke patients. Through a systematic review, the objective was to determine whether robot-assisted gait training with the Lokomat® is more effective in enhancing lower extremity rehabilitation in patients with stroke in comparison to conventional physical therapy (CPT).

Methods

In this study, a systematic search was conducted in various databases, including CINAHL, MEDLINE, PubMed, Embase, Cochrane Library, Scopus, Web of Science, and Physiotherapy Evidence Database (PEDro), as well as bibliographies of previous meta-analyses, to identify all randomized controlled trials that investigated the use of Lokomat® devices in adult stroke patients. The study aimed to derive pooled estimates of standardized mean differences for six outcomes, namely, Fugl-Meyer Assessment lower-extremity subscale (FMA-LE), Berg Balance Scale (BBS), gait speed, functional ambulation category scale (FAC), timed up and go (TUG), and functional independence measure (FIM), through random effects meta-analyses.

Results

The review analyzed 21 studies with a total of 709 participants and found that the use of Lokomat® in stroke patients resulted in favorable outcomes for the recovery of balance as measured by the BBS (mean difference = 2.71, 95% CI 1.39 to 4.03; p < 0.0001). However, the FAC showed that Lokomat® was less effective than the CPT group (mean difference = -0.28, 95% CI -0.45 to 0.11, P = 0.001). There were no significant differences in FMA-LE (mean difference = 1.27, 95% CI -0.88 to 3.42, P = 0.25), gait speed (mean difference = 0.02, 95% CI -0.03 to 0.07, P = 0.44), TUG (mean difference = -0.12, 95% CI -0.71 to 0.46, P = 0.68), or FIM (mean difference = 2.12, 95% CI -2.92 to 7.16, P = 0.41) between the Lokomat® and CPT groups for stroke patients.

Conclusion

Our results indicate that, with the exception of more notable improvements in balance, robot-assisted gait training utilizing the Lokomat® was not superior to CPT based on the current literature. Considering its ability to reduce therapists' work intensity and burden, the way in which Lokomat® is applied should be strengthened, or future randomized controlled trial studies should use more sensitive assessment criteria.

Efficacy of Robot-Assisted and Virtual Reality Interventions on Balance, Gait, and Daily Function in Patients With Stroke: A Systematic Review and Network Meta-analysis

OBJECTIVE

This study aimed to evaluate the comparative effectiveness and ranking of robot-assisted training, virtual reality, and robot-assisted rehabilitation combined with virtual reality in improving balance, gait, and daily function in patients with stroke.

DATA SOURCES

PubMed, EMBASE, the Cochrane Library, Physiotherapy Evidence Database, CINAHL, Web of Science, and ProQuest Dissertations and Theses abstracting and indexing databases were comprehensively searched to include randomized controlled trials published through August 31, 2022.

STUDY SELECTION

Randomized controlled trials comparing robot-assisted training, virtual reality, robot-assisted rehabilitation combined with virtual reality, and conventional therapy to assess the effects on balance, gait, and daily function of patients with stroke.

DATA EXTRACTION

The risk of bias was assessed using the Cochrane Risk of Bias tool and the methodological quality of the studies was assessed using the Physiotherapy Evidence Database scale. A network meta-analysis of random effects models was performed for direct and indirect effects. Data were analyzed using Stata SE 17.0 and R 4.2.1.

DATA SYNTHESIS

A total of 52 randomized controlled trials involving 1,559 participants were included in this study. Based on the ranking probabilities, robot-assisted rehabilitation combined with virtual reality was most effective in improving balance (surface under the cumulative ranking curve [SUCRA]=82.0%; mean difference [MD]=4.10; 95% confidence interval [CI], 0.43 to 7.67). Virtual reality was most effective in improving velocity (SUCRA=97.8%; MD=-0.15; 95% CI, -0.24 to -0.06) and daily function (SUCRA=92.1%; MD=-7.85; 95% CI, -15.18 to -1.07).

CONCLUSIONS

Compared to robot-assisted training and conventional therapy, robot-assisted training combined virtual reality was most likely the best intervention for balance, and virtual reality might be the most helpful in improving daily function for patients after stroke. Further studies are needed to clarify the specific efficacy of robot-assisted training combined with virtual reality and virtual reality on gait.

Prefrontal activation in response to a plantar contact task under open and closed eye conditions in patients with cerebral infarction

Objective

This study investigates the effect of a bilateral (paralyzed side, healthy side) plantar contact task on dorsolateral prefrontal activation in patients recovering from cerebral infarction under open and closed eye conditions.

Methods

We selected 10 patients with cerebral infarction, admitted to the neurorehabilitation center of Beijing Rehabilitation Hospital, affiliated with Capital Medical University, from January 2019 to July 2020, who met our established criteria. Under open-eye and closed-eye conditions, the paralyzed and healthy sides performed the plantar contact tasks separately. The dorsolateral prefrontal region was monitored simultaneously with functional near-infrared spectroscopy (fNIRS), and activation was analyzed according to the curve-type changes of oxyhemoglobin and deoxyhemoglobin changes in the dorsolateral prefrontal cortex with 560 near-infrared monitoring channels.

Results

After stratifying the data based on the eyes-open and eyes-closed conditions, some degree of heterogeneity was observed between the layers. Under the eyes-closed condition, the Pearson χ2 was 0.142, with a p value of 0.706, indicating no significant impact of the eyes-closed condition on the activation of the dorsolateral prefrontal cortex during the plantar task, whether performed on the paralyzed or the healthy side.In contrast, the Pearson χ2 value was 15.15 for the eyes-open condition, with a p value of 0.002. This suggests that carrying out the plantar task, either on the paralyzed or the healthy side, with eyes open significantly influenced the activation of the dorsolateral prefrontal cortex. Furthermore, activation of the dorsolateral prefrontal cortex was 1.55 times higher when the task was executed with the paralyzed side compared to the healthy side. This implies that the paralyzed side was more likely to activate the dorsolateral prefrontal lobe when performing the plantar contact task under eyes-open conditions.

Conclusion

Observations via fNIRS revealed that the plantar contact task elicited dorsolateral prefrontal cortex activation. Moreover, the activation effect was intensified when performed on the paralyzed side under eyes-open conditions. Therapeutic methods that leverage these findings-namely cognitive-motor therapies that promote the recovery of motor functions by activating cognitive control brain regions via perception (information construction)-may hold promise.

Investigating the Effect of Novel Gamified Stepper on Lower Limb Biomechanics in Seated Healthy Subjects

The present study introduces a new gamified stepper device designed for bilateral lower limb rehabilitation, which is combined with a 3-D exergame. To the best of our knowledge, this is the initial study to utilize the stepping exercise for seated lower limb rehabilitation. The device comprises a stepping mechanism and a magnetic encoder. The modified stepper facilitates the bilateral training in the lower limb within its workspace. The magnetic encoder provides real-time rotational angle data during the exercise. A task-specific exergame platform was created and integrated with the device to enhance user compliance and engagement with the exercise. Experiments were conducted with ten healthy individuals with no history of lower limb injury to evaluate the system's feasibility for providing bilateral training and the effectiveness of the exergame platform. Participants were asked to perform bilateral lower limb exercise with a metronome and gamified stepper device in a seated position. Lower limb range of motion (ROM) and EMG activations were recorded during the exercises. The results indicate that the device was capable of providing cyclical ROM training with reduced muscle activation of the lower limb, and the exergame platform increased motivation to continue the exercises. This study can serve as the foundation for developing a robotic version of the proposed stepper device.

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.

Patent Review of Lower Limb Rehabilitation Robotic Systems by Sensors and Actuation Systems Used

Robotic systems for lower limb rehabilitation are essential for improving patients' physical conditions in lower limb rehabilitation and assisting patients with various locomotor dysfunctions. These robotic systems mainly integrate sensors, actuation, and control systems and combine features from bionics, robotics, control, medicine, and other interdisciplinary fields. Several lower limb robotic systems have been proposed in the patent literature; some are commercially available. This review is an in-depth study of the patents related to robotic rehabilitation systems for lower limbs from the point of view of the sensors and actuation systems used. The patents awarded and published between 2013 and 2023 were investigated, and the temporal distribution of these patents is presented. Our results were obtained by examining the analyzed information from the three public patent databases. The patents were selected so that there were no duplicates after several filters were used in this review. For each patent database, the patents were analyzed according to the category of sensors and the number of sensors used. Additionally, for the main categories of sensors, an analysis was conducted depending on the type of sensors used. Afterwards, the actuation solutions for robotic rehabilitation systems for upper limbs described in the patents were analyzed, highlighting the main trends in their use. The results are presented with a schematic approach so that any user can easily find patents that use a specific type of sensor or a particular type of actuation system, and the sensors or actuation systems recommended to be used in some instances are highlighted.

Stimulation enhancement effect of the combination of exoskeleton-assisted hand rehabilitation and fingertip haptic stimulation

Introduction

Providing stimulation enhancements to existing hand rehabilitation training methods may help stroke survivors achieve better treatment outcomes. This paper presents a comparison study to explore the stimulation enhancement effects of the combination of exoskeleton-assisted hand rehabilitation and fingertip haptic stimulation by analyzing behavioral data and event-related potentials.

Methods

The stimulation effects of the touch sensations created by a water bottle and that created by cutaneous fingertip stimulation with pneumatic actuators are also investigated. Fingertip haptic stimulation was combined with exoskeleton-assisted hand rehabilitation while the haptic stimulation was synchronized with the motion of our hand exoskeleton. In the experiments, three experimental modes, including exoskeleton-assisted grasping motion without haptic stimulation (Mode 1), exoskeleton-assisted grasping motion with haptic stimulation (Mode 2), and exoskeleton-assisted grasping motion with a water bottle (Mode 3), were compared.

Results

The behavioral analysis results showed that the change of experimental modes had no significant effect on the recognition accuracy of stimulation levels (p = 0.658), while regarding the response time, exoskeleton-assisted grasping motion with haptic stimulation was the same as grasping a water bottle (p = 0.441) but significantly different from that without haptic stimulation (p = 0.006). The analysis of event-related potentials showed that the primary motor cortex, premotor cortex, and primary somatosensory areas of the brain were more activated when both the hand motion assistance and fingertip haptic feedback were provided using our proposed method (P300 amplitude 9.46 μV). Compared to only applying exoskeleton-assisted hand motion, the P300 amplitude was significantly improved by providing both exoskeleton-assisted hand motion and fingertip haptic stimulation (p = 0.006), but no significant differences were found between any other two modes (Mode 2 vs. Mode 3: p = 0.227, Mode 1 vs. Mode 3: p = 0.918). Different modes did not significantly affect the P300 latency (p = 0.102). Stimulation intensity had no effect on the P300 amplitude (p = 0.295, 0.414, 0.867) and latency (p = 0.417, 0.197, 0.607).

Discussion

Thus, we conclude that combining exoskeleton-assisted hand motion and fingertip haptic stimulation provided stronger stimulation on the motor cortex and somatosensory cortex of the brain simultaneously; the stimulation effects of the touch sensations created by a water bottle and that created by cutaneous fingertip stimulation with pneumatic actuators are similar.

Feasibility of an Intelligent Algorithm Based on an Assist-as-Needed Controller for a Robot-Aided Gait Trainer (Lokomat) in Neurological Disorders: A Longitudinal Pilot Study

Most robotic gait assisted devices are designed to provide constant assistance during the training without taking into account each patient's functional ability. The Lokomat offers an assist-as-needed control via the integrated exercise "Adaptive Gait Support" (AGS), which adapts the robotic support based on the patient's abilities. The aims of this study were to examine the feasibility and characteristics of the AGS during long-term application. Ten patients suffering from neurological diseases underwent an 8-week Lokomat training with the AGS. They additionally performed conventional walking tests and a robotic force measurement. The difference between robotic support during adaptive and conventional training and the relationship between the robotic assessment and the conventional walking and force tests were examined. The results show that AGS is feasible during long-term application in a heterogeneous population. The support during AGS training in most of the gait phases was significantly lower than during conventional Lokomat training. A relationship between the robotic support level determined by the AGS and conventional walking tests was revealed. Moreover, combining the isometric force data and AGS data could divide patients into clusters, based on their ability to generate high forces and their level of motor control. AGS shows a high potential in assessing patients' walking ability, as well as in providing challenging training, e.g., by automatically adjusting the robotic support throughout the whole gait cycle and enabling training at lower robotic support.

Is Leg-Driven Treadmill-Based Exoskeleton Robot Training Beneficial to Poststroke Patients: A Systematic Review and Meta-analysis

OBJECTIVE

The aim of the study is to systematically review the effects of leg-driven treadmill-based exoskeleton robot training on balance and walking ability in poststroke patients.

DESIGN

The PubMed, Cochrane Library, Embase, Web of Science, Medline, CNKI, VIP, and Wanfang databases were searched from inception to August 2021. The literature quality was evaluated using Cochrane Handbook. Primary outcomes include the Functional Ambulation Category Scale and Berg Balance Scale, and secondary outcomes include the 10 meter walk test, 6 minute walk test, and gait assessment cadence were analyzed.

RESULTS

Seventeen randomized controlled trials were included in the systematic review, 15 studies in meta-analysis. Primary outcomes showed no significant difference in the Functional Ambulation Category Scale score; subgroup with the exoskeleton robot + conventional therapy of the Berg Balance Scale score was significantly increased; secondary outcomes showed no significance in 6 minute walk test or 10 meter walk test. The cadence score increased for the subgroup with an onset of more than 6 mos in the treatment group. The control group performed better than the subgroup with an onset of less than 6 mos.

CONCLUSIONS

Leg-driven treadmill-based exoskeleton robot training can improve balance function in poststroke patients and is beneficial for patients with an onset of greater than 6 mos. However, there is no evidence to support the efficacy of walking ability.

Robot-assisted rehabilitation training improves knee function and daily activity ability in older adults following total knee arthroplasty

To evaluate the effects of robot-assisted rehabilitation training on knee function and the daily activity ability of older adults following total knee arthroplasty (TKA). Eighty-eight patients who underwent TKA were randomly assigned to a robot-assisted rehabilitation or traditional therapy group. The patients in the control group were treated with traditional manual rehabilitation therapy, while the patients in the experimental group were subjected to the robot-assisted rehabilitation program. Range of motion of the knee joint, Hospital for Special Surgery Knee Rating Score, and the modified Barthel Index were assessed on the first or second day after TKA (preintervention) and the discharge day (postintervention). Additionally, the length of hospital stay and related hospitalization expenses of the two groups were collected on the discharge day. Improvements in the active range of motion (p < 0.001), passive range of motion (p = 0.001), Hospital for Special Surgery Knee Rating Score (p < 0.001), and modified Barthel Index score (p = 0.004) were significantly better in the robot-assisted rehabilitation group than in the traditional therapy group. Interestingly, the length of hospital stay in the experimental group (9 days) was shorter than that in the control group (13 days), and the total cost of hospitalization was lower (p = 0.002). The robot-assisted rehabilitation training program is an effective intervention that significantly improves the daily activity ability and knee function of older adults following TKA.

Control strategies used in lower limb exoskeletons for gait rehabilitation after brain injury: a systematic review and analysis of clinical effectiveness

BACKGROUND

In the past decade, there has been substantial progress in the development of robotic controllers that specify how lower-limb exoskeletons should interact with brain-injured patients. However, it is still an open question which exoskeleton control strategies can more effectively stimulate motor function recovery. In this review, we aim to complement previous literature surveys on the topic of exoskeleton control for gait rehabilitation by: (1) providing an updated structured framework of current control strategies, (2) analyzing the methodology of clinical validations used in the robotic interventions, and (3) reporting the potential relation between control strategies and clinical outcomes.

METHODS

Four databases were searched using database-specific search terms from January 2000 to September 2020. We identified 1648 articles, of which 159 were included and evaluated in full-text. We included studies that clinically evaluated the effectiveness of the exoskeleton on impaired participants, and which clearly explained or referenced the implemented control strategy.

RESULTS

(1) We found that assistive control (100% of exoskeletons) that followed rule-based algorithms (72%) based on ground reaction force thresholds (63%) in conjunction with trajectory-tracking control (97%) were the most implemented control strategies. Only 14% of the exoskeletons implemented adaptive control strategies. (2) Regarding the clinical validations used in the robotic interventions, we found high variability on the experimental protocols and outcome metrics selected. (3) With high grade of evidence and a moderate number of participants (N = 19), assistive control strategies that implemented a combination of trajectory-tracking and compliant control showed the highest clinical effectiveness for acute stroke. However, they also required the longest training time. With high grade of evidence and low number of participants (N = 8), assistive control strategies that followed a threshold-based algorithm with EMG as gait detection metric and control signal provided the highest improvements with the lowest training intensities for subacute stroke. Finally, with high grade of evidence and a moderate number of participants (N = 19), assistive control strategies that implemented adaptive oscillator algorithms together with trajectory-tracking control resulted in the highest improvements with reduced training intensities for individuals with chronic stroke.

CONCLUSIONS

Despite the efforts to develop novel and more effective controllers for exoskeleton-based gait neurorehabilitation, the current level of evidence on the effectiveness of the different control strategies on clinical outcomes is still low. There is a clear lack of standardization in the experimental protocols leading to high levels of heterogeneity. Standardized comparisons among control strategies analyzing the relation between control parameters and biomechanical metrics will fill this gap to better guide future technical developments. It is still an open question whether controllers that provide an on-line adaptation of the control parameters based on key biomechanical descriptors associated to the patients' specific pathology outperform current control strategies.

Dynamic analysis and control of a hybrid lower limb rehabilitation robot to reduce human-robot interaction forces

This study presents a model of cooperation between two planar manipulators including an orthosis and a programmable plate in form of a hybrid lower limb rehabilitation robot, which was designed and built at the University of Guilan. The aims of cooperation are to distribute the power required to move between the cooperative manipulators and also reduce the interaction forces between orthosis and leg. The cooperation is performed with two modes using the adjustment of the plate forces, a constant force in the vertical direction (CFV) and variant force proportional to orthosis torque (VFPOT). Kinematic and dynamic analysis of the hybrid lower limb rehabilitation robot and its control are also discussed in this study. The performance and effectiveness of the proposed hybrid robot are demonstrated on a healthy person in real-time. Each walking trial lasted 60 s and repeated 20 times for every mode. The walking speed was considered to be 1.5 km/h and weight compensator was adjusted with a constant weight unloading level of 70%. The results show that the VFPOT mode leads to a 45% reduction in the driving torque of the hip and knee joints compared to orthosis-only. This reduction is expected to reduce interaction force at the connection straps. So, it provides more patient comfort and safety, which can be effective in improving the time and process of rehabilitation.

Case report: A novel approach of closed-loop brain stimulation combined with robot gait training in post-stroke gait disturbance

Most post-stroke patients have long-lasting gait disturbances that reduce their daily activities. They often show impaired hip and knee joint flexion and ankle dorsiflexion of the lower limbs during the swing phase of gait, which is controlled by the corticospinal tract from the primary motor cortex (M1). Recently, we reported that gait-synchronized closed-loop brain stimulation targeting swing phase-related activity in the affected M1 can improve gait function in post-stroke patients. Subsequently, a gait-training robot (Orthobot^®) was developed that could assist lower-limb joint movements during the swing phase of gait. Therefore, we investigated whether gait-synchronized closed-loop brain stimulation combined with robot-assisted training targeting the swing phase could enhance the recovery of post-stroke gait disturbance. A 57-year-old female patient with chronic post-stroke hemiparesis underwent closed-loop brain stimulation combined with robot-assisted training for 10 min 2 years after left pons infarction. For closed-loop brain stimulation, we used transcranial oscillatory electrical current stimulation over the lesioned M1 foot area with 1.5 mA of DC offset and 0-3 mA of sine-wave formed currents triggered by the paretic heel contact to set the maximum current just before the swing phase (intervention A; two times repeated, A1 and A2). According to the N-of-1 study design, we also performed sham stimulation (intervention B) and control stimulation not targeting the swing phase (intervention C) combined with robot-assisted training in the order of A1-B-A2-C interventions. As a result, we found larger improvements in gait speed, the Timed Up and Go test result, and muscle strength after the A1 and A2 interventions than after the B and C interventions. After confirming the short-term effects, we performed an additional long-term intervention twice a week for 5 weeks, for a total of 10 sessions. Gait parameters also largely improved after long-term intervention. Gait-synchronized closed-loop brain stimulation combined with robot-assisted training targeting the swing phase of gait may promote the recovery of gait function in post-stroke patients. Further studies with a larger number of patients are necessary.

Comparison of theoretical and experimental models for knee flexion/extension using a cable-driven robot

To support and facilitate the rehabilitation of patients with physical limitations and aid the therapist, several robotic structures are being studied. Among the structures, the cable-driven robots stand out. The cable-driven robots are structures actuated by cables and have the advantages of being flexible and reconfigurable for each patient. The objective of this paper is to develop a theoretical model for knee flexion/extension force and moment using a cable-driven robot. The proposed model is necessary for elaborating a referential to which diagnosis can be made and the improvement of the patient evaluated. The presented theoretical model was validated through experiments with twelve sedentary and healthy volunteers. The first procedure tested ten subjects in three thigh angles for knee flexion motion; the second procedure tested two subjects in flexion and extension for the same thigh angle. The results show the validity of the model for 88.58% of the tests in an ANOVA analysis with a 99% confidence interval. The similarity of data for different gender, ages, and intrinsic factors was noted, implying that the model is representative and independent of the subject’s individuality. Differences between flexion and extension values were observed, which need to be studied in the future.

Using robot-assisted stiffness perturbations to evoke aftereffects useful to post-stroke gait rehabilitation

Stroke is a major global issue, affecting millions every year. When a stroke occurs, survivors are often left with physical disabilities or difficulties, frequently marked by abnormal gait. Post-stroke gait normally presents as one of or a combination of unilaterally shortened step length, decreased dorsiflexion during swing phase, and decreased walking speed. These factors lead to an increased chance of falling and an overall decrease in quality of life due to a reduced ability to locomote quickly and safely under one's own power. Many current rehabilitation techniques fail to show lasting results that suggest the potential for producing permanent changes. As technology has advanced, robot-assisted rehabilitation appears to have a distinct advantage, as the precision and repeatability of such an intervention are not matched by conventional human-administered therapy. The possible role in gait rehabilitation of the Variable Stiffness Treadmill (VST), a unique, robotic treadmill, is further investigated in this paper. The VST is a split-belt treadmill that can reduce the vertical stiffness of one of the belts, while the other belt remains rigid. In this work, we show that the repeated unilateral stiffness perturbations created by this device elicit an aftereffect of increased step length that is seen for over 575 gait cycles with healthy subjects after a single 10-min intervention. These long aftereffects are currently unmatched in the literature according to our knowledge. This step length increase is accompanied by kinematics and muscle activity aftereffects that help explain functional changes and have their own independent value when considering the characteristics of post-stroke gait. These results suggest that repeated unilateral stiffness perturbations could possibly be a useful form of post-stroke gait rehabilitation.

Three-Dimensional Gait Analysis and sEMG Measures for Robotic-Assisted Gait Training in Subacute Stroke: A Randomized Controlled Trial

Background

The efficacy of robotic-assisted gait training (RAGT) should be considered versatilely; among which, gait assessment is one of the most important measures; observational gait assessment is the most commonly used method in clinical practice, but it has certain limitations due to the deviation of subjectivity; instrumental assessments such as three-dimensional gait analysis (3DGA) and surface electromyography (sEMG) can be used to obtain gait data and muscle activation during walking in stroke patients with hemiplegia, so as to better evaluate the rehabilitation effect of RAGT.

Objective

This single-blind randomized controlled trial is aimed at analyzing the impact of RAGT on the 3DGA parameters and muscle activation in patients with subacute stroke and evaluating the clinical effect of improving walking function of RAGT.

Methods

This randomized controlled trial evaluated the improvement of 4-week RAGT on patients with subacute stroke by 3DGA and surface electromyography (sEMG), combined with clinical scales: experimental group (n = 18, 20 sessions of RAGT) or control group (n = 16, 20 sessions of conventional gait training). Gait performance was evaluated by the 3DGA, and clinical evaluations based on Fugl-Meyer assessment for lower extremity (FMA-LE), functional ambulation category (FAC), and 6-minute walk test (6MWT) were used. Of these patients, 30 patients underwent sEMG measurement synchronized with 3DGA; the cocontraction index in swing phase of the knee and ankle of the affected side was calculated.

Results

After 4 weeks of intervention, intragroup comparison showed that walking speed, temporal symmetry, bilateral stride length, range of motion (ROM) of the bilateral hip, flexion angle of the affected knee, ROM of the affected ankle, FMA-LE, FAC, and 6MWT in the experimental group were significantly improved (p < 0.05), and in the control group, significant improvements were observed in walking speed, temporal symmetry, stride length of the affected side, ROM of the affected hip, FMA-LE, FAC, and 6MWT (p < 0.05). Intergroup comparison showed that the experimental group significantly outperformed the control group in walking speed, temporal symmetry of the spatiotemporal parameters, ROM of the affected hip and peak flexion of the knee in the kinematic parameters, and the FMA-LE and FAC in the clinical scale (p < 0.05). In patients evaluated by sEMG, the experimental group showed a noticeable improvement in the cocontraction index of the knee (p = 0.042), while no significant improvement was observed in the control group (p = 0.196), and the experimental group was better than the control group (p = 0.020). No noticeable changes were observed in the cocontraction index of the ankle in both groups (p > 0.05).

Conclusions

Compared with conventional gait training, RAGT successfully improved part of the spatiotemporal parameters of patients and optimized the motion of the affected lower limb joints and muscle activation patterns during walking, which is crucial for further rehabilitation of walking ability in patients with subacute stroke. This trial is registered with ChiCTR2200066402.

Planar Model for Vibration Analysis of Cable Rehabilitation Robots

Cable robots are widely used in the field of rehabilitation. These robots differ from other cable robots because the cables are rather short and are usually equipped with magnetic hooks to improve the ease of use. The vibrations of rehabilitation robots are dominated by the effects of the hooks and payloads, whereas the cables behave as massless springs. In this paper, a 2D model of the cables of a robot that simulates both longitudinal and transverse vibrations is developed and experimentally validated. Then the model is extended to simulate the vibrations of an actual 3D robot in the symmetry planes. Finally, the calculated modal properties (natural frequencies and modes of vibration) are compared with the typical spectrum of excitation due to the cable’s motion. Only the first transverse mode can be excited during the rehabilitation exercise.

Development of a novel body weight support system for gait rehabilitation

Modern rehabilitation processes for neurological patients have been widely assisted by robotic structures, with continuous research and improvements. The use of robotic assistance in rehabilitation is a consolidated technique for upper limb training sessions. However, human gait robotic rehabilitation still needs further research and development. Based on that, this paper deals with the development of a novel active body weight support (BWS) system integrated with a serious game for poststroke patients. This paper starts with a brief review of the state of the art of applied technologies for gait rehabilitation. Next, it presents the obtained mathematical model followed by multibody synthesis techniques and meta-heuristic optimization to the proposed device. The control of the structure is designed using proportional integral derivative (PID) controllers tuned with meta-heuristic optimization and associated with a suppression function to perform assist-as-needed actions. Then, the prototype is integrated with a serious game designed specifically for this application. Finally, a pilot study is conducted with the structure and healthy volunteers. The results obtained show that the mobility of the novel BWS is as expected and the proposed system potentially offers a novel tool for gait training.

A triple-step controller with linear active disturbance rejection control for a lower limb rehabilitation robot

Lower limb rehabilitation robots (LLRRs) have shown promising potential in assisting hemiplegic patients to recover their motor function. During LLRR-aided rehabilitation, the dynamic uncertainties due to human-robot coupling, model uncertainties, and external disturbances, make it challenging to achieve high accuracy and robustness in trajectory tracking. In this study, we design a triple-step controller with linear active disturbance rejection control (TSC-LADRC) for a LLRR, including the steady-state control, feedforward control, and feedback control. The steady-state control and feedforward control are developed to compensate for the gravity and incorporate the reference dynamics information, respectively. Based on the linear active disturbance rejection control, the feedback control is designed to enhance the control performance under dynamic uncertainties. Numerical simulations and experiments are conducted to validate the effectiveness of TSC-LADRC. The results of simulations illustrate that the tracking errors under TSC-LADRC are obviously smaller than those under the triple-step controller without LADRC (TSC), especially with the change of external loads. Moreover, the experiment results of six healthy subjects reveal that the proposed method achieves higher accuracy and lower energy consumption than TSC. Therefore, TSC-LADRC has the potential to assist hemiplegic patients in rehabilitation training.

G-Exos: A wearable gait exoskeleton for walk assistance

Stroke is the second leading cause of death and one of the leading causes of disability in the world. According to the World Health Organization, 11 million people suffer a stroke yearly. The cost of the disease is exorbitant, and the most widely used treatment is conventional physiotherapy. Therefore, assistive technology emerges to optimize rehabilitation and functional capabilities, but cost, robustness, usability, and long-term results still restrict the technology selection. This work aimed to develop a low-cost ankle orthosis, the G-Exos, a wearable exoskeleton to increase motor capability by assisting dorsiflexion, plantarflexion, and ankle stability. A hybrid system provided near-natural gait movements using active, motor, and passive assistance, elastic band. The system was validated with 10 volunteers with foot drop: seven with stroke, two with incomplete spinal cord injury (SCI), and one with acute inflammatory transverse myelitis (ATM). The G-Exos showed assistive functionality for gait movement. A Friedman test showed a significant difference in dorsiflexion amplitude with the use of the G-Exos compared to gait without the use of the G-Exos [x²₍₃₎ = 98.56, p < 0.001]. In addition, there was also a significant difference in ankle eversion and inversion comparing walking with and without the G-Exos [x²₍₃₎ = 36.12, p < 0.001]. The G-Exos is a robust, lightweight, and flexible assistive technology device to detect the gait phase accurately and provide better human-machine interaction. G-Exos training improved capability to deal with gait disorders, usability, and motor and functional recovery. Wearable assistive technologies lead to a better quality of life and contribute using in activities of daily living.

Efficacy of Robot-Assisted Gait Training Combined with Robotic Balance Training in Subacute Stroke Patients: A Randomized Clinical Trial

Recently, the use of robotic technology in gait and balance rehabilitation of stroke patients has been introduced, with positive results. The purpose of this study was to evaluate the effectiveness of robotic gait and trunk rehabilitation compared to robotic gait training alone on balance, activities, and participation measures in patients with subacute stroke. The study was a randomized, controlled, single blind, parallel group clinical trial. Thirty-six patients with first ischemic or hemorrhagic stroke event were enrolled, and they were randomized in two groups: Gait Group (GG), where they received only robotic treatment for gait rehabilitation through an end-effector system, and Gait/Trunk Group (GTG) where they performed end-effector gait rehabilitation and balance with a robotic platform, 3 times/week for 12 sessions/month. At the end of the study, there was an improvement in balance ability in both groups. Instead, the lower limb muscle strength and muscle tone significantly improved only in the GTG group, where we found a significant reduction in the trunk oscillations and displacement during dynamic exercises more than the GG group. The robotic platform which was added to the gait robotic treatment offers more intense and controlled training of the trunk that positively influences the tone and strength of lower limb muscles.

Detection and assessment of Parkinson's disease based on gait analysis: A survey

Neurological disorders represent one of the leading causes of disability and mortality in the world. Parkinson's Disease (PD), for example, affecting millions of people worldwide is often manifested as impaired posture and gait. These impairments have been used as a clinical sign for the early detection of PD, as well as an objective index for pervasive monitoring of the PD patients in daily life. This review presents the evidence that demonstrates the relationship between human gait and PD, and illustrates the role of different gait analysis systems based on vision or wearable sensors. It also provides a comprehensive overview of the available automatic recognition systems for the detection and management of PD. The intervening measures for improving gait performance are summarized, in which the smart devices for gait intervention are emphasized. Finally, this review highlights some of the new opportunities in detecting, monitoring, and treating of PD based on gait, which could facilitate the development of objective gait-based biomarkers for personalized support and treatment of PD.

Rehabilitation robotics after stroke: a bibliometric literature review

INTRODUCTION

Stroke is the leading cause of long-term disability in developed countries. Due to population aging, the number of people requiring rehabilitation after stroke is going to rise in the coming decades. Robot-mediated neurorehabilitation has the potential to improve clinical outcomes of rehabilitation treatments. A statistical analysis of the literature aims to focus on the main trend of this topic.

AREAS COVERED

A bibliometric survey on post-stroke robotic rehabilitation was performed through a database collection of scientific publications in the field of rehabilitation robotics. By covering the last 20 years, 17429 sources were collected. Relevant patterns and statistics concerning the main research areas were analyzed. Leading journals and conferences which publish and disseminate knowledge in the field were identified. A detailed nomenclature study was carried out. The time trends of the research field were captured. Opinions and predictions of future trends that are expected to shape the near future of the field were discussed.

EXPERT OPINION

Data analysis reveals the continuous expansion of the research field over the last two decades, which is expected to rise considerably in near future. More attention will be paid to the lower limbs rehabilitation and disease/design specific applications in early-stage patients.

Accurate Real-time Phase Estimation for Normal and Asymmetric Gait

An accurate real-time gait phase estimator for normal and asymmetric gait is developed by training and testing a time-delay neural network on gait data collected from six participants during treadmill walking. The trained model can generate smooth and highly accurate predictions of the gait phase with a root mean square error of less than 3.48% and 4.31% in normal and asymmetric gait, respectively. The coefficient of determination between the estimated and target phase is greater than 99% for all subjects with both normal and asymmetric gait. The proposed gait estimator also exhibits precise heel-strike event detection with an RMSE of 2.56% and 3.70% in normal and asymmetric gait, respectively. A spatial impedance controller is then employed and tested based on the estimated gait phase of a new participant. Obtained results confirm that the controller provided assistance in coordination with the user's motion both in normal and asymmetric gait conditions. The estimated gait phase is compared in the case of walking without and with the exoskeleton in passive and active modes, indicating persistent accuracy of the gait phase estimator regardless of the walking conditions.