Neurophysiology of robot-mediated training and therapy: a perspective for future use in clinical populations

Glial Cell Reprogramming in Ischemic Stroke: A Review of Recent Advancements and Translational Challenges

Ischemic stroke, the second leading cause of death worldwide and the leading cause of long-term disabilities, presents a significant global health challenge, particularly in aging populations where the risk and severity of cerebrovascular events are significantly increased. The aftermath of stroke involves neuronal loss in the infarct core and reactive astrocyte proliferation, disrupting the neurovascular unit, especially in aged brains. Restoring the balance between neurons and non-neuronal cells within the perilesional area is crucial for post-stroke recovery. The aged post-stroke brain mounts a fulminant proliferative astroglial response, leading to gliotic scarring that prevents neural regeneration. While countless therapeutic techniques have been attempted for decades with limited success, alternative strategies aim to transform inhibitory gliotic tissue into an environment conducive to neuronal regeneration and axonal growth through genetic conversion of astrocytes into neurons. This concept gained momentum following discoveries that in vivo direct lineage reprogramming in the adult mammalian brain is a feasible strategy for reprogramming non-neuronal cells into neurons, circumventing the need for cell transplantation. Recent advancements in glial cell reprogramming, including transcription factor-based methods with factors like NeuroD1, Ascl1, and Neurogenin2, as well as small molecule-induced reprogramming and chemical induction, show promise in converting glial cells into functional neurons. These approaches leverage the brain's intrinsic plasticity for neuronal replacement and circuit restoration. However, applying these genetic conversion therapies in the aged, post-stroke brain faces significant challenges, such as the hostile inflammatory environment and compromised regenerative capacity. There is a critical need for safe and efficient delivery methods, including viral and non-viral vectors, to ensure targeted and sustained expression of reprogramming factors. Moreover, addressing the translational gap between preclinical successes and clinical applications is essential, emphasizing the necessity for robust stroke models that replicate human pathophysiology. Ethical considerations and biosafety concerns are critically evaluated, particularly regarding the long-term effects and potential risks of genetic reprogramming. By integrating recent research findings, this comprehensive review provides an in-depth understanding of the current landscape and future prospects of genetic conversion therapy for ischemic stroke rehabilitation, highlighting the potential to enhance personalized stroke management and regenerative strategies through innovative approaches.

Combined robot-assisted therapy virtual reality for upper limb rehabilitation in stroke survivors: a systematic review of randomized controlled trials

BACKGROUND

Upper limb impairments are among the most common consequences following a stroke. Recently, robot-assisted therapy (RT) and virtual reality (VR) have been used to improve upper limb function in stroke survivors.

OBJECTIVES

This review aims to investigate the effects of combined RT and VR on upper limb function in stroke survivors and to provide recommendations for researchers and clinicians in the medical field.

METHODS

We searched PubMed, SCOPUS, REHABDATA, PEDro, EMBASE, and Web of Science from inception to March 28, 2024. Randomized controlled trials (RCTs) involving stroke survivors that compared combined RT and VR interventions with either passive (i.e., sham, rest) or active (i.e., traditional therapy, VR, RT) interventions and assessed outcomes related to upper limb function (e.g., strength, muscle tone, or overall function) were included. The Cochrane Collaboration tool was used to evaluate the methodological quality of the included studies.

RESULTS

Six studies were included in this review. In total, 201 patients with stroke (mean age 57.84 years) were involved in this review. Four studies were considered 'high quality', while two were considered as 'moderate quality' on the Cochrane Collaboration tool. The findings showed inconsistent results for the effects of combined RT and VR interventions on upper limb function poststroke.

CONCLUSION

In conclusion, there are potential effects of combined RT and VR interventions on improving upper limb function, but further research is needed to confirm these findings, understand the underlying mechanisms, and assess the consistency and generalizability of the results.

May the force be with you: exploring force discrimination in chimpanzees using the force-feedback device

While force-feedback devices have been developed in areas such as virtual reality, there have been very few comparative cognitive studies in nonhuman animals using these devices. In addition, although cross-modal perception between vision and touch has been actively studied in nonhuman primates for several decades, there have been no studies of their active haptic perception. In this study, we attempted to train force discrimination in chimpanzees using a force-feedback device modified from a trackball. Chimpanzees were given different levels of force feedback (8.0 vs. 0.5 N) when moving the on-screen cursor to the target area by manipulating the trackball and were required to select one of two choice stimuli based on the force cue. The experiment was conducted using a trial-block procedure in which the same force stimulus was presented for a fixed number of trials, and the force stimulus was changed between blocks. The block size was progressively reduced from ten trials. Four chimpanzees were trained, but none reached the learning criterion (80% or more correct responses under the condition that the force stimuli were presented randomly). However, a detailed analysis of the chimpanzees' performance before and after the trial-block switching revealed that their choice behavior could not be explained by a simple win-stay/lose-shift strategy, suggesting that the switching of the force stimuli affected the chimpanzees' choice behavior. It was also found that the chimpanzees performed better when switching from small to large force stimuli than when switching from large to small force stimuli. Although none of the chimpanzees in this study acquired force discrimination, future studies using such force-feedback devices will provide new insights for understanding haptic cognition in nonhuman primates from a comparative cognitive perspective.

Rehabilitation Training after Spinal Cord Injury Affects Brain Structure and Function: From Mechanisms to Methods

Spinal cord injury (SCI) is a serious neurological insult that disrupts the ascending and descending neural pathways between the peripheral nerves and the brain, leading to not only functional deficits in the injured area and below the level of the lesion but also morphological, structural, and functional reorganization of the brain. These changes introduce new challenges and uncertainties into the treatment of SCI. Rehabilitation training, a clinical intervention designed to promote functional recovery after spinal cord and brain injuries, has been reported to promote activation and functional reorganization of the cerebral cortex through multiple physiological mechanisms. In this review, we evaluate the potential mechanisms of exercise that affect the brain structure and function, as well as the rehabilitation training process for the brain after SCI. Additionally, we compare and discuss the principles, effects, and future directions of several rehabilitation training methods that facilitate cerebral cortex activation and recovery after SCI. Understanding the regulatory role of rehabilitation training at the supraspinal center is of great significance for clinicians to develop SCI treatment strategies and optimize rehabilitation plans.

Utilizing mobile robotics for pelvic perturbations to improve balance and cognitive performance in older adults: a randomized controlled trial

Late-life balance disorders remain a severe problem with fatal consequences. Perturbation-based balance training (PBT), a form of rehabilitation that intentionally introduces small, unpredictable disruptions to an individual's gait cycle, can improve balance. The Tethered Pelvic Assist Device (TPAD) is a cable-driven robotic trainer that applies perturbations to the user's pelvis during treadmill walking. Earlier work showcased improved gait stability and the first evidence of increased cognition acutely. The mobile Tethered Pelvic Assist Device (mTPAD), a portable version of the TPAD, applies perturbations to a pelvic belt via a posterior walker during overground gait, as opposed to treadmill walking. Forty healthy older adults were randomly assigned to a control group (CG, n = 20) without mTPAD PBT or an experimental group (EG, n = 20) with mTPAD PBT for a two-day study. Day 1 consisted of baseline anthropometrics, vitals, and functional and cognitive measurements. Day 2 consisted of training with the mTPAD and post-interventional cognitive and functional measurements. Results revealed that the EG significantly outperformed the CG in several cognitive (SDMT-C and TMT-B) and functional (BBS and 4-Stage Balance: one-foot stand) measurements while showcasing increased confidence in mobility based on FES-I. To our knowledge, our study is the first randomized, large group (n = 40) clinical study exploring new mobile perturbation-based robotic gait training technology.

Effects of Training with a Powered Exoskeleton on Cortical Activity Modulation in Hemiparetic Chronic Stroke Patients: A Randomized Controlled Pilot Trial

OBJECTIVES

To investigate the effects of exoskeleton-assisted gait training in stroke patients.

DESIGN

Prospective randomized controlled trial.

SETTING

Rehabilitation department in a single tertiary hospital.

PARTICIPANTS

Thirty (N=30) chronic stroke patients with Functional Ambulatory Category scale (FAC) between 2 and 4.

INTERVENTION

Patients were randomly assigned to 1 of 2 groups: training with Healbot G, a wearable powered exoskeleton (Healbot G group; n=15), or treadmill training (control group; n=15). All participants received 30 minutes of training, 10 times per week, for 4 weeks.

OUTCOME MEASUREMENTS

The primary outcome was oxyhemoglobin level changes, representing cortical activity in both motor cortices using functional near-infrared spectroscopy. The secondary outcomes included FAC, Berg Balance Scale, Motricity Index for the lower extremities (MI-Lower), 10-meter walk test, and gait symmetry ratio (spatial step and temporal symmetry ratio).

RESULTS

Compared to the control group, during the entire training session, the pre-training and post-training mean cortical activity, and the amount of increment between pre- and post-training were significantly higher in the Healbot G group (∆mean ± SD; pre-training, 0.245±0.119, post-training, 0.697±0.429, between pre- and post-training, 0.471±0.401μmol, P<.001). There was no significant difference in cortical activity between affected- and unaffected hemispheres after Healbot G training. FAC (∆mean ± SD; 0.35 ± 0.50, P=.012), MI-Lower (∆mean ± SD; 7.01 ± 0.14, P=.001), and spatial step gait symmetry ratio (∆mean ± SD; -0.32 ± 0.25, P=.049) were improved significantly in the Healbot G group.

CONCLUSION

Exoskeleton-assisted gait training induces cortical modulation effect in both motor cortices, a balanced cortical activation pattern with improvements in spatial step symmetry ratio, walking ability, and voluntary strength.

Overground Robotic Exoskeleton Training for Patients With Stroke on Walking-Related Outcomes: A Systematic Review and Meta-analysis of Randomized Controlled Trials

OBJECTIVE

This review aims to evaluate the effectiveness of solely overground robotic exoskeleton (RE) training or overground RE training with conventional rehabilitation in improving walking ability, speed, and endurance among patients with stroke.

DATA SOURCES

Nine databases, 5 trial registries, gray literature, specified journals, and reference lists from inception until December 27, 2021.

STUDY SELECTION

Randomized controlled trials adopting overground robotic exoskeleton training for patients with any phases of stroke on walking-related outcomes were included.

DATA EXTRACTION

Two independent reviewers extracted items and performed risk of bias using the Cochrane Risk of Bias tool 1 and certainty of evidence using the Grades of Recommendation Assessment, Development, and Evaluation.

DATA SYNTHESIS

Twenty trials involving 758 participants across 11 countries were included in this review. The overall effect of overground robotic exoskeletons on walking ability at postintervention (d=0.21; 95% confidence interval [CI], 0.01, 0.42; Z=2.02; P=.04) and follow-up (d=0.37; 95% CI, 0.03, 0.71; Z=2.12; P=.03) and walking speed at postintervention (d=0.23; 95% CI, 0.01, 0.46; Z=2.01; P=.04) showed significant improvement compared with conventional rehabilitation. Subgroup analyses suggested that RE training should combine with conventional rehabilitation. A preferable gait training regime is <4 times per week over ≥6 weeks for ≤30 minutes per session among patients with chronic stroke and ambulatory status of independent walkers before training. Meta-regression did not identify any effect of the covariates on the treatment effect. The majority of randomized controlled trials had small sample sizes, and the certainty of the evidence was very low.

CONCLUSION

Overground RE training may have a beneficial effect on walking ability and walking speed to complement conventional rehabilitation. Further large-scale and long-term, high-quality trials are recommended to enhance the quality of overground RE training and confirm its sustainability.

Feasibility and Efficacy of the Newly Developed Robotic Hybrid Assistive Limb Shoulder Exercises in Patients with C5 Palsy during the Acute Postoperative Phase

Background and Objectives: Although postoperative C5 palsy is a frequent complication of cervical spine surgery, no effective therapeutic rehabilitation approach has been established for postoperative C5 palsy. The purpose of this study was to find evidence confirming the effectiveness and feasibility of robotic Hybrid Assistive Limb (HAL) shoulder exercises for C5 palsy. Materials and Methods: In this before-after, uncontrolled case series clinical study, we performed a mean of 11.7 shoulder training sessions using a shoulder HAL immediately after the onset of C5 palsy in seven shoulders of six patients who developed postoperative C5 palsy and had difficulty raising their shoulder during the acute postoperative phase of cervical spine surgery. Shoulder HAL training was introduced as early as possible after evaluating the general condition of all inpatients who developed C5 palsy. Patients underwent shoulder abduction training using shoulder HAL on an inpatient and outpatient basis at 2-week or 1-month intervals. Adverse events associated with shoulder HAL training were investigated. The shoulder abduction angle and power without the shoulder HAL were evaluated before shoulder HAL usage, at every subsequent session, and upon completion of all sessions. Results: Severe adverse events due to shoulder HAL training were not reported. After completion of all shoulder HAL sessions, all patients showed improved shoulder elevation, while shoulder abduction angle and power improved over time. Conclusions: Shoulder elevation training with HAL in patients in the acute stage of postoperative C5 palsy has the potential to demonstrate improvement in shoulder joint function with a low risk of developing severe adverse events.

The effectiveness of robotic-assisted upper limb rehabilitation to improve upper limb function in patients with cervical spinal cord injuries: a systematic literature review

Background

Spinal Cord Injury (SCI) damages corticospinal tracts and descending motor pathways responsible for transmitting signals from the brain to the spinal cord, leading to temporary or permanent changes in sensation, motor function, strength, and body function below the site of injury. Cervical SCI (cSCI), which leads to tetraplegia, causes severe functional upper limb (UL) impairments that increase falls risk, limits independence, and leads to difficulties with activities of daily living (ADLs). Robotic therapy (RT) has been developed in recent decades as a new treatment approach for people with cervical spinal cord injuries (cSCI). The present review aimed to explore current available evidence and studies regarding the effectiveness of RT for individuals with cSCI in improving UL function, identify current research gaps and future research directions.

Method

This review was conducted by searching PubMed, CINAHL, Medline, Embase, and APA PsycInfo for relevant studies published from January 2010 to January 2022. Selected studies were analyzed with a focus on the patients' self-perception of limited UL function and level of independence in activities of daily living. In addition, the JBI Critical Appraisal checklist was used to assess study quality.

Results

A total of 7 articles involving 87 patients (74 males and 13 females) were included in the analysis, with four studies utilizing exoskeleton and three studies utilizing end-effector robotic devices, respectively. The quality of these studies varied between JBI Critical Appraisal scores of 4 to 8. Several studies lacked blinding and a control group which affected internal validity. Nevertheless, four out of seven studies demonstrated statistically significant improvements in outcome measurements on UL function and strength after RT.

Conclusion

This review provided mixed evidence regarding the effectiveness of RT as a promising intervention approach to improve upper limb function in participants with cSCI. Although RT was shown to be safe, feasible, and reduces active therapist time, further research on the long-term effects of UL RT is still needed. Nevertheless, this review serves as a useful reference for researchers to further develop exoskeletons with practical and plausible applications toward geriatric orthopaedics.

Utilizing Mobile Robotics for Pelvic Perturbations to Improve Balance and Cognitive Performance in Older Adults: A Randomized Controlled Trial

Late-life balance disorders remain a severe problem with fatal consequences. Perturbation-based balance training (PBT), a form of rehabilitation that intentionally introduces small, unpredictable disruptions to an individual's gait cycle, can improve balance. The Tethered Pelvic Assist Device (TPAD) is a cable-driven robotic trainer that applies perturbations to the user's pelvis during treadmill walking. Earlier work showcased improved gait stability and the first evidence of increased cognition acutely. The mobile Tethered Pelvic Assist Device (mTPAD), a portable version of the TPAD, applies perturbations to a pelvic belt via a posterior walker during overground gait, as opposed to treadmill walking. Forty healthy older adults were randomly assigned to a control group (CG, n = 20) without mTPAD PBT or an experimental group (EG, n = 20) with mTPAD PBT for a two-day study. Day 1 consisted of baseline anthropometrics, vitals, and functional and cognitive measurements. Day 2 consisted of training with the mTPAD and post-interventional cognitive and functional measurements. Results revealed that the EG significantly outperformed the CG in cognitive and functional tasks while showcasing increased confidence in mobility. Gait analysis demonstrated that the mTPAD PBT significantly improved mediolateral stability during lateral perturbations. To our knowledge, our study is the first randomized, large group (n = 40) clinical study exploring new mobile perturbation-based robotic gait training technology.

The identification of interacting brain networks during robot-assisted training with multimodal stimulation

Objective.Robot-assisted rehabilitation training is an effective way to assist rehabilitation therapy. So far, various robotic devices have been developed for automatic training of central nervous system following injury. Multimodal stimulation such as visual and auditory stimulus and even virtual reality technology were usually introduced in these robotic devices to improve the effect of rehabilitation training. This may need to be explained from a neurological perspective, but there are few relevant studies.Approach.In this study, ten participants performed right arm rehabilitation training tasks using an upper limb rehabilitation robotic device. The tasks were completed under four different feedback conditions including multiple combinations of visual and auditory components: auditory feedback; visual feedback; visual and auditory feedback (VAF); non-feedback. The functional near-infrared spectroscopy devices record blood oxygen signals in bilateral motor, visual and auditory areas. Using hemoglobin concentration as an indicator of cortical activation, the effective connectivity of these regions was then calculated through Granger causality.Main results.We found that overall stronger activation and effective connectivity between related brain regions were associated with VAF. When participants completed the training task without VAF, the trends in activation and connectivity were diminished.Significance.This study revealed cerebral cortex activation and interacting networks of brain regions in robot-assisted rehabilitation training with multimodal stimulation, which is expected to provide indicators for further evaluation of the effect of rehabilitation training, and promote further exploration of the interaction network in the brain during a variety of external stimuli, and to explore the best sensory combination.

Alteration of muscle activity during voluntary rehabilitation training with single-joint Hybrid Assistive Limb (HAL) in patients with shoulder elevation dysfunction from cervical origin

Shoulder elevation, defined here as arm raising, being essential for activities of daily living, dysfunctions represent a substantial burden in patients' lives. Owing to the complexity of the shoulder joint, the tightly coordinated muscular activity is a fundamental component, and neuromuscular impairments have devastating effects. A single-joint shoulder type version of the Hybrid Assistive Limb (HAL) allowing motion assistance based on the intention of the user via myoelectric activation has recently been developed, and its safety was demonstrated for shoulder rehabilitation. Yet, little is known about the physiological effects of the device. This study aims to monitor the changes in muscle activity and motion during shoulder HAL rehabilitation in several patients suffering from shoulder elevation dysfunction from cervical radicular origin. 8 patients (6 males, 2 females, mean age 62.4 ± 9.3 years old) with weakness of the deltoid muscle resulting from a damage to the C5 nerve root underwent HAL-assisted rehabilitation. We combined surface electromyography and three-dimensional motion capture to record muscular activity and kinematics. All participants showed functional recovery, with improvements in their Manual Muscle Testing (MMT) scores and range of motion (ROM). During training, HAL decreased the activity of deltoid and trapezius, significantly more for the latter, as well as the coactivation of both muscles. We also report a reduction of the characteristic shrugging compensatory motion which is an obstacle to functional recovery. This reduction was notably demonstrated by a stronger reliance on the deltoid rather than the trapezius, indicating a muscle coordination tending toward a pattern similar to healthy individuals. Altogether, the results of the evaluation of motion and muscular changes hint toward a functional recovery in acute, and chronic shoulder impairments from cervical radicular origin following shoulder HAL rehabilitation training and provide information on the physiological effect of the device.

A Tenodesis-Induced-Grip exoskeleton robot (TIGER) for assisting upper extremity functions in stroke patients: a randomized control study

PURPOSE

This study was aimed toward developing a lightweight assisting tenodesis-induced-grip exoskeleton robot (TIGER) and to examine the performance of the TIGER in stroke patients with hemiplegia.

METHODS

This was a single-blinded, randomized control trial with pre-treatment, immediate post-treatment, and 12-week follow-up assessments. Thirty-four stroke patients were recruited and randomized to either an experimental or control group, where each participant in both groups underwent 40 min of training. In addition to a 20-min bout of regular task-specific motor training, each participant in the experimental group received 20 min of TIGER training, and the controls received 20 min of traditional occupational therapy in each treatment session. Primary outcomes based on the Fugl-Meyer Motor Assessment of Upper Extremity (FMA-UE) were recorded.

RESULTS

Thirty-two patients (94.1%) completed the study: 17 and 15 patients in the experimental and control groups, respectively. Significant beneficial effects were found on the total score (ANCOVA, p = 0.006), the wrist score (ANCOVA, p = 0.037), and the hand score (ANCOVA, p = 0.006) for the FMA-UE in the immediate post-treatment assessment of the participants receiving the TIGER training.

CONCLUSION

The TIGER has beneficial effects on remediating upper limb impairments in chronic stroke patients. Clinical trial registration: ClinicalTrials.gov; identifier NCT03713476Implications for rehabilitationBased on use-dependent plasticity concepts, robot training with the more distal segments of the upper extremities has a beneficial effect in patients with chronic stroke.A novel lightweight assisting tenodesis-induced-grip exoskeleton robot (TIGER) system using a mechanism involving musculotendinous coordination of the wrist and hand was proposed in this study.Between-group differences in changes in the upper limb motor performance were observed in the experimental group as compared to patients in the control group. For patients with chronic stroke, receiving 20 min of TIGER training in conjunction with 20 min of task-specific motor training led to clinically important changes in motor control and functioning of the affected upper limb.

sEMG-Based Gain-Tuned Compliance Control for the Lower Limb Rehabilitation Robot during Passive Training

The lower limb rehabilitation robot is a typical man-machine coupling system. Aiming at the problems of insufficient physiological information and unsatisfactory safety performance in the compliance control strategy for the lower limb rehabilitation robot during passive training, this study developed a surface electromyography-based gain-tuned compliance control (EGCC) strategy for the lower limb rehabilitation robot. First, the mapping function relationship between the normalized surface electromyography (sEMG) signal and the gain parameter was established and an overall EGCC strategy proposed. Next, the EGCC strategy without sEMG information was simulated and analyzed. The effects of the impedance control parameters on the position correction amount were studied, and the change rules of the robot end trajectory, man-machine contact force, and position correction amount analyzed in different training modes. Then, the sEMG signal acquisition and feature analysis of target muscle groups under different training modes were carried out. Finally, based on the lower limb rehabilitation robot control system, the influence of normalized sEMG threshold on the robot end trajectory and gain parameters under different training modes was experimentally studied. The simulation and experimental results show that the adoption of the EGCC strategy can significantly enhance the compliance of the robot end-effector by detecting the sEMG signal and improve the safety of the robot in different training modes, indicating the EGCC strategy has good application prospects in the rehabilitation robot field.

Relation between Cortical Activation and Effort during Robot-Mediated Walking in Healthy People: A Functional Near-Infrared Spectroscopy Neuroimaging Study (fNIRS)

Force and effort are important components of a motor task that can impact rehabilitation effectiveness. However, few studies have evaluated the impact of these factors on cortical activation during gait. The purpose of the study was to investigate the relation between cortical activation and effort required during exoskeleton-mediated gait at different levels of physical assistance in healthy individuals. Twenty-four healthy participants walked 10 m with an exoskeleton that provided four levels of assistance: 100%, 50%, 0%, and 25% resistance. Functional near-infrared spectroscopy (fNIRS) was used to measure cerebral flow dynamics with a 20-channel (plus two reference channels) device that covered most cortical motor regions bilaterally. We measured changes in oxyhemoglobin (HbO2) and deoxyhemoglobin (HbR). According to HbO2 levels, cortical activation only differed slightly between the assisted conditions and rest. In contrast, bilateral and widespread cortical activation occurred during the two unassisted conditions (somatosensory, somatosensory association, primary motor, premotor, and supplementary motor cortices). A similar pattern was seen for HbR levels, with a smaller number of significant channels than for HbO2. These results confirmed the hypothesis that there is a relation between cortical activation and level of effort during gait. This finding should help to optimize neurological rehabilitation strategies to drive neuroplasticity.

Machine learning predicts clinically significant health related quality of life improvement after sensorimotor rehabilitation interventions in chronic stroke

Health related quality of life (HRQOL) reflects individuals perceived of wellness in health domains and is often deteriorated after stroke. Precise prediction of HRQOL changes after rehabilitation interventions is critical for optimizing stroke rehabilitation efficiency and efficacy. Machine learning (ML) has become a promising outcome prediction approach because of its high accuracy and easiness to use. Incorporating ML models into rehabilitation practice may facilitate efficient and accurate clinical decision making. Therefore, this study aimed to determine if ML algorithms could accurately predict clinically significant HRQOL improvements after stroke sensorimotor rehabilitation interventions and identify important predictors. Five ML algorithms including the random forest (RF), k-nearest neighbors (KNN), artificial neural network, support vector machine and logistic regression were used. Datasets from 132 people with chronic stroke were included. The Stroke Impact Scale was used for assessing multi-dimensional and global self-perceived HRQOL. Potential predictors included personal characteristics and baseline cognitive/motor/sensory/functional/HRQOL attributes. Data were divided into training and test sets. Tenfold cross-validation procedure with the training data set was used for developing models. The test set was used for determining model performance. Results revealed that RF was effective at predicting multidimensional HRQOL (accuracy: 85%; area under the receiver operating characteristic curve, AUC-ROC: 0.86) and global perceived recovery (accuracy: 80%; AUC-ROC: 0.75), and KNN was effective at predicting global perceived recovery (accuracy: 82.5%; AUC-ROC: 0.76). Age/gender, baseline HRQOL, wrist/hand muscle function, arm movement efficiency and sensory function were identified as crucial predictors. Our study indicated that RF and KNN outperformed the other three models on predicting HRQOL recovery after sensorimotor rehabilitation in stroke patients and could be considered for future clinical application.

Involvement of the Rostromedial Prefrontal Cortex in Human-Robot Interaction: fNIRS Evidence From a Robot-Assisted Motor Task

Assistive exoskeleton robots are being widely applied in neurorehabilitation to improve upper-limb motor and somatosensory functions. During robot-assisted exercises, the central nervous system appears to highly attend to external information-processing (IP) to efficiently interact with robotic assistance. However, the neural mechanisms underlying this process remain unclear. The rostromedial prefrontal cortex (rmPFC) may be the core of the executive resource allocation that generates biases in the allocation of processing resources toward an external IP according to current behavioral demands. Here, we used functional near-infrared spectroscopy to investigate the cortical activation associated with executive resource allocation during a robot-assisted motor task. During data acquisition, participants performed a right-arm motor task using elbow flexion-extension movements in three different loading conditions: robotic assistive loading (ROB), resistive loading (RES), and non-loading (NON). Participants were asked to strive for kinematic consistency in their movements. A one-way repeated measures analysis of variance and general linear model-based methods were employed to examine task-related activity. We demonstrated that hemodynamic responses in the ventral and dorsal rmPFC were higher during ROB than during NON. Moreover, greater hemodynamic responses in the ventral rmPFC were observed during ROB than during RES. Increased activation in ventral and dorsal rmPFC subregions may be involved in the executive resource allocation that prioritizes external IP during human-robot interactions. In conclusion, these findings provide novel insights regarding the involvement of executive control during a robot-assisted motor task.

Electromechanical and Robotic Devices for Gait and Balance Rehabilitation of Children with Neurological Disability: A Systematic Review

In the last two decades, a growing interest has been focused on gait and balance robot-assisted rehabilitation in children with neurological disabilities. Robotic devices allow the implementation of intensive, task-specific training fostering functional recovery and neuroplasticity phenomena. However, limited attention has been paid to the protocols used in this research framework. This systematic review aims to provide an overview of the existing literature on robotic systems for the rehabilitation of gait and balance in children with neurological disabilities and their rehabilitation applications. The literature search was carried out independently and synchronously by three authors on the following databases: MEDLINE, Cochrane Library, PeDro, Institute of Electrical and Electronics Engineers, ScienceDirect, and Google Scholar. The data collected included three subsections referring to clinical, technical, and regulatory aspects. Thirty-one articles out of 81 found on the primary literature search were included in the systematic review. Most studies involved children with cerebral palsy. Only one-third of the studies were randomized controlled trials. Overall, 17 devices (nine end-effector systems and eight exoskeletons) were investigated, among which only 4 (24%) were bore the CE mark. Studies differ on rehabilitation protocols duration, intensity, and outcome measures. Future research should improve both rehabilitation protocols’ and devices’ descriptions.

Upper Limb Robotic Rehabilitation for Patients with Cervical Spinal Cord Injury: A Comprehensive Review

The upper extremities limitation represents one of the essential functional impairments in patients with cervical spinal cord injury. Electromechanics assisted devices and robots are increasingly used in neurorehabilitation to help functional improvement in patients with neurological diseases. This review aimed to systematically report the evidence-based, state-of-art on clinical applications and robotic-assisted arm training (RAT) in motor and functional recovery in subjects affected by cervical spinal cord injury. The present study has been carried out within the framework of the Italian Consensus Conference on "Rehabilitation assisted by robotic and electromechanical devices for persons with disability of neurological origin" (CICERONE). PubMed/MEDLINE, Cochrane Library, and Physiotherapy Evidence Database (PEDro) databases were systematically searched from inception to September 2021. The 10-item PEDro scale assessed the study quality for the RCT and the AMSTAR-2 for the systematic review. Two different authors rated the studies included in this review. If consensus was not achieved after discussion, a third reviewer was interrogated. The five-item Oxford CEBM scale was used to rate the level of evidence. A total of 11 studies were included. The selected studies were: two systematic reviews, two RCTs, one parallel-group controlled trial, one longitudinal intervention study and five case series. One RCT was scored as a high-quality study, while the systematic review was of low quality. RAT was reported as feasible and safe. Initial positive effects of RAT were found for arm function and quality of movement in addition to conventional therapy. The high clinical heterogeneity of treatment programs and the variety of robot devices could severely affect the generalizability of the study results. Therefore, future studies are warranted to standardize the type of intervention and evaluate the role of robotic-assisted training in subjects affected by cervical spinal cord injury.

Abnormal synergistic gait mitigation in acute stroke using an innovative ankle-knee-hip interlimb humanoid robot: a preliminary randomized controlled trial

Abnormal spasticity and associated synergistic patterns are the most common neuromuscular impairments affecting ankle–knee–hip interlimb coordinated gait kinematics and kinetics in patients with hemiparetic stroke. Although patients with hemiparetic stroke undergo various treatments to improve gait and movement, it remains unknown how spasticity and associated synergistic patterns change after robot-assisted and conventional treatment. We developed an innovative ankle–knee–hip interlimb coordinated humanoid robot (ICT) to mitigate abnormal spasticity and synergistic patterns. The objective of the preliminary clinical trial was to compare the effects of ICT combined with conventional physical therapy (ICT-C) and conventional physical therapy and gait training (CPT-G) on abnormal spasticity and synergistic gait patterns in 20 patients with acute hemiparesis. We performed secondary analyses aimed at elucidating the biomechanical effects of Walkbot ICT on kinematic (spatiotemporal parameters and angles) and kinetic (active force, resistive force, and stiffness) gait parameters before and after ICT in the ICT-C group. The intervention for this group comprised 60-min conventional physical therapy plus 30-min robot-assisted training, 7 days/week, for 2 weeks. Significant biomechanical effects in knee joint kinematics; hip, knee, and ankle active forces; hip, knee, and ankle resistive forces; and hip, knee, and ankle stiffness were associated with ICT-C. Our novel findings provide promising evidence for conventional therapy supplemented by robot-assisted therapy for abnormal spasticity, synergistic, and altered biomechanical gait impairments in patients in the acute post-stroke recovery phase.

Trial Registration: Clinical Trials.gov identifier NCT03554642 (14/01/2020).

State of the art and challenges for the classification of studies on electromechanical and robotic devices in neurorehabilitation: a scoping review

INTRODUCTION

The rapid development of electromechanical and robotic devices has profoundly influenced neurorehabilitation. Growth in the scientific and technological aspects thereof is crucial for increasing the number of newly developed devices, and clinicians have welcomed such growth with enthusiasm. Nevertheless, improving the standard for the reporting clinical, technical, and normative aspects of such electromechanical and robotic devices remains an unmet need in neurorehabilitation. Accordingly, this study aimed to analyze the existing literature on electromechanical and robotic devices used in neurorehabilitation, considering the current clinical, technical, and regulatory classification systems.

EVIDENCE ACQUISITION

Within the CICERONE Consensus Conference framework, studies on electromechanical and robotic devices used for upper- and lower-limb rehabilitation in persons with neurological disabilities in adulthood and childhood were reviewed. We have conducted a literature search using the following databases: MEDLINE, Cochrane Library, PeDro, Institute of Electrical and Electronics Engineers, Science Direct, and Google Scholar. Clinical, technical, and regulatory classification systems were applied to collect information on the electromechanical and robotic devices. The study designs and populations were investigated.

EVIDENCE SYNTHESIS

Overall, 316 studies were included in the analysis. More than half (52%) of the studies were randomised controlled trials (RCTs). The population investigated the most suffered from strokes, followed by spinal cord injuries, multiple sclerosis, cerebral palsy, and traumatic brain injuries. In total, 100 devices were described; of these, 19% were certified with the CE mark. Overall, the main type of device was an exoskeleton. However, end-effector devices were primarily used for the upper limbs, whereas exoskeletons were used for the lower limbs (for both children and adults).

CONCLUSIONS

The current literature on robotic neurorehabilitation lacks detailed information regarding the technical characteristics of the devices used. This affects the understanding of the possible mechanisms underlying recovery. Unfortunately, many electromechanical and robotic devices are not provided with CE marks, strongly hindering the research on the clinical outcomes of rehabilitation treatments based on these devices. A more significant effort is needed to improve the description of the robotic devices used in neurorehabilitation in terms of the technical and functional details, along with high-quality RCT studies.

TeachBot: Towards teaching robotics fundamentals for human-robot collaboration at work

The shortage of skilled workers who can use robots is a crucial issue hampering the growth of manufacturing industries. We present a new type of workforce training system, TeachBot, in which a robotic instructor delivers a series of interactive lectures using graphics and physical demonstration of its arm movements. Furthermore, the TeachBot allows learners to physically interact with the robot. This new human-computer interface, integrating oral and graphical instructions with motion demonstration and physical touch, enables to create engaging training materials. Effective learning takes place when the learner simultaneously interacts with an embodiment of new knowledge. We apply this “Learning by Touching” methodology to teach basic concepts, e.g. how a shaft encoder and feedback control work. In a pilot randomized control test with a small number of human subjects, we find suggestive evidence that Learning by Touching enhances learning effectiveness in this robotic context for adult learners. Students whose learning experience included touching the robot as opposed to watching it delivers the lessons showed gains in their ability to integrate knowledge about robotics. The “touching” group showed statistically significant gains in self-efficacy, which is an important antecedent to further learning and successful use of new technologies, as well as gains in knowledge about robotic concepts that trend toward significance.

Effectiveness of robotic-assisted therapy for upper extremity function in children and adolescents with cerebral palsy: a systematic review protocol

INTRODUCTION

The application of advanced technologies in paediatric rehabilitation to improve performance and enhance everyday functioning shows considerable promise. The aims of this systematic review are to investigate the effectiveness of robotic-assisted therapy for upper extremity function in children and adolescents with cerebral palsy and to extend the scope of intervention from empirical evidence.

METHODS AND ANALYSIS

Multiple databases, including MEDLINE (Ovid), PubMed, CINAHL, Scopus, Web of Science, Cochrane Library and IEEE Xplore, will be comprehensively searched for relevant randomised controlled trials and non-randomised studies. The grey literature will be accessed on the ProQuest Dissertations & Theses Global database, and a hand search from reference lists of previous articles will be performed. The papers written in English language will be considered, with no limitation on publication date. Two independent reviewers will identify eligible studies, evaluate the level of evidence (the Oxford Centre for Evidence-Based Medicine) and appraise methodological quality and risk of bias (the Standard quality assessment criteria for evaluating primary research papers from a variety of fields (QualSyst tool); the Grading of Recommendations Assessment, Development and Evaluation). Data will be appropriately extracted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline. A narrative synthesis will be provided to summarise the results, and a meta-analysis will be conducted if there is sufficient homogeneity across outcomes.

PROSPERO REGISTRATION NUMBER

CRD42020205818.

ETHICS AND DISSEMINATION

Ethical approval is not required for this study. The findings will be disseminated via a peer-reviewed journal and international conferences.

Effects of a Soft Robotic Hand for Hand Rehabilitation in Chronic Stroke Survivors

OBJECTIVES

Soft robotic hands are proposed for stroke rehabilitation in terms of their high compliance and low inherent stiffness. We investigated the clinical efficacy of a soft robotic hand that could actively flex and extend the fingers in chronic stroke subjects with different levels of spasticity.

METHODS

Sixteen chronic stroke subjects were recruited into this single-group study. Subjects underwent 20 sessions of 1-hour EMG-driven soft robotic hand training. Training effect was evaluated by the pre-training and post-training assessments with the clinical scores: Action Research Arm Test(ARAT), Fugl-Meyer Assessment for Upper Extremity(FMA-UE), Box-and-Block test(BBT), Modified Ashworth Scale(MAS), and maximum voluntary grip strength.

RESULTS

For all the recruited subjects (n = 16), significant improvement of upper limb function was generally observed in ARAT (increased mean=2.44, P = 0.032), FMA-UE (increased mean=3.31, P = 0.003), BBT (increased mean=1.81, P = 0.024), and maximum voluntary grip strength (increased mean=2.14 kg, P < 0.001). No significant change was observed in terms of spasticity with the MAS (decreased mean=0.11, P = 0.423). Further analysis showed subjects with mild or no finger flexor spasticity (MAS<2, n = 9) at pre-training had significant improvement of upper limb function after 20 sessions of training. However, for subjects with moderate and severe finger flexor spasticity (MAS=2,3, n = 7) at pre-training, no significant change in clinical scores was shown and only maximum voluntary grip strength had significant increase.

CONCLUSION

EMG-driven rehabilitation training using the soft robotic hand with flexion and extension could be effective for the functional recovery of upper limb in chronic stroke subjects with mild or no spasticity.

Robot-Assisted Therapy for Upper Extremity Motor Impairment After Stroke: A Systematic Review and Meta-Analysis

OBJECTIVE

The purpose of this study was to review the effects of robot-assisted therapy (RT) for improving poststroke upper extremity motor impairment.

METHODS

The PubMed, Embase, Medline, and Web of Science databases were searched from inception to April 8, 2020. Randomized controlled trials that were conducted to evaluate the effects of RT on upper extremity motor impairment poststroke and that used Fugl-Meyer assessment for upper extremity scores as an outcome were included. Two authors independently screened articles, extracted data, and assessed the methodological quality of the included studies using the Physiotherapy Evidence Database (PEDro) scale. A random-effects meta-analysis was performed to pool the effect sizes across the studies.

RESULTS

Forty-one randomized controlled trials with 1916 stroke patients were included. Compared with dose-matched conventional rehabilitation, RT significantly improved the Fugl-Meyer assessment for upper extremity scores of the patients with stroke, with a small effect size (Hedges g = 0.25; 95% CI, 0.11-0.38; I2 = 45.9%). The subgroup analysis revealed that the effects of unilateral RT, but not that of bilateral RT, were superior to conventional rehabilitation (Hedges g = 0.32; 95% CI, 0.15-0.50; I2 = 55.9%). Regarding the type of robot devices, the effects of the end effector device (Hedges g = 0.22; 95% CI, 0.09-0.36; I2 = 35.4%), but not the exoskeleton device, were superior to conventional rehabilitation. Regarding the stroke stage, the between-group difference (ie, RT vs convention rehabilitation) was significant only for people with late subacute or chronic stroke (Hedges g = 0.33; 95% CI, 0.16-0.50; I2 = 34.2%).

CONCLUSION

RT might be superior to conventional rehabilitation in improving upper extremity motor impairment in people after stroke with notable upper extremity hemiplegia and limited potential for spontaneous recovery.

Converging Robotic Technologies in Targeted Neural Rehabilitation: A Review of Emerging Solutions and Challenges

Recent advances in the field of neural rehabilitation, facilitated through technological innovation and improved neurophysiological knowledge of impaired motor control, have opened up new research directions. Such advances increase the relevance of existing interventions, as well as allow novel methodologies and technological synergies. New approaches attempt to partially overcome long-term disability caused by spinal cord injury, using either invasive bridging technologies or noninvasive human-machine interfaces. Muscular dystrophies benefit from electromyography and novel sensors that shed light on underlying neuromotor mechanisms in people with Duchenne. Novel wearable robotics devices are being tailored to specific patient populations, such as traumatic brain injury, stroke, and amputated individuals. In addition, developments in robot-assisted rehabilitation may enhance motor learning and generate movement repetitions by decoding the brain activity of patients during therapy. This is further facilitated by artificial intelligence algorithms coupled with faster electronics. The practical impact of integrating such technologies with neural rehabilitation treatment can be substantial. They can potentially empower nontechnically trained individuals-namely, family members and professional carers-to alter the programming of neural rehabilitation robotic setups, to actively get involved and intervene promptly at the point of care. This narrative review considers existing and emerging neural rehabilitation technologies through the perspective of replacing or restoring functions, enhancing, or improving natural neural output, as well as promoting or recruiting dormant neuroplasticity. Upon conclusion, we discuss the future directions for neural rehabilitation research, diagnosis, and treatment based on the discussed technologies and their major roadblocks. This future may eventually become possible through technological evolution and convergence of mutually beneficial technologies to create hybrid solutions.

The effectiveness of a robotic tilt table on the muscle strength and quality of life in individuals following stroke: a randomised control trial

Background/Aims

Stroke is a common, serious and disabling condition. There is a need for early rehabilitation to cut the long-term ill effects of stroke and to maximise functional recovery. This study aimed to assess the effect of Erigo tilt table training on muscle strength and quality of life in individuals who have survived a stroke.

Methods

A total of 133 patients were recruited and randomly assigned to receive conventional physiotherapy (group A) or Erigo tilt table training (group B). Both groups underwent an intervention programme lasting 30 days. Quality of life and muscle strength were assessed at baseline (day 0), at the end of the intervention (day 30) and at follow up (day 90).

Results

Overall, 110 patients completed the study: 55 in group A and 55 in group B. Quality of life and muscle strength significantly improved between baseline and follow up with both interventions. Group A's quality of life and upper and lower muscle strength scores increased from 75, 0.57 and 1.0 at baseline to 89, 3.0 and 3.5 at follow up, respectively; while group B's scores increased from 75, 1.35 and 1.43 at baseline to 102, 3.0 and 3.64 at follow up. The Erigo tilt table resulted in significantly greater improvements than conventional physiotherapy (P<0.01).

Conclusions

The Erigo tilt-table could be valuable tool in the early rehabilitation of patients with acute hemiplegia as it improves muscle strength and quality of life to a greater extent than conventional physiotherapy.

The Impact of Robotic Rehabilitation on the Motor System in Neurological Diseases. A Multimodal Neurophysiological Approach

Motor disability is a key feature of many neurological diseases, influencing the social roles of affected patients and their ability to perform daily life activities. Current rehabilitation capacities are overwhelmed by the age-related increase of motor dysfunctions seen, for example, in stroke, extrapyramidal or neuromuscular diseases. As the patient to rehabilitation personnel ration increases, robotic solutions might establish the possibility to rapidly satisfy the increasing demand for rehabilitation. This paper presents an inaugural exploratory study which investigates the interchangeability of a novel experimental robotic rehabilitation device system with classical physical therapy, using a multimodal neurophysiological assessment of the motor system-quantitative electroencephalogram (EEG), motor conduction times and turn/amplitude analysis. Preliminary results show no significant difference between the two methods; however, a significant effect of the therapy was found on different pathologies (beneficial for vascular and extrapyramidal, or limited, and only on preventing reduction of joint movements in neuromuscular).

Wearable Physiological Monitoring System Based on Electrocardiography and Electromyography for Upper Limb Rehabilitation Training

Secondary injuries are common during upper limb rehabilitation training because of uncontrollable physical force and overexciting activities, and long-time training may cause fatigue and reduce the training effect. This study proposes a wearable monitoring device for upper limb rehabilitation by integrating electrocardiogram and electromyogram (ECG/EMG) sensors and using data acquisition boards to obtain accurate signals during robotic glove assisting training. The collected ECG/EMG signals were filtered, amplified, digitized, and then transmitted to a remote receiver (smart phone or laptop) via a low-energy Bluetooth module. A software platform was developed for data analysis to visualize ECG/EMG information, and integrated into the robotic glove control module. In the training progress, various hand activities (i.e., hand closing, forearm pronation, finger flexion, and wrist extension) were monitored by the EMG sensor, and the changes in the physiological status of people (from excited to fatigue) were monitored by the ECG sensor. The functionality and feasibility of the developed physiological monitoring system was demonstrated by the assisting robotic glove with an adaptive strategy for upper limb rehabilitation training improvement. The feasible results provided a novel technique to monitor individual ECG and EMG information holistically and practically, and a technical reference to improve upper limb rehabilitation according to specific treatment conditions and the users' demands. On the basis of this wearable monitoring system prototype for upper limb rehabilitation, many ECG-/EMG-based mobile healthcare applications could be built avoiding some complicated implementation issues such as sensors management and feature extraction.

Feasibility of Robot-assisted Rehabilitation in Poststroke Recovery of Upper Limb Function Depending on the Severity

The single-joint Hybrid Assistive Limb (HAL-SJ) robot is an exoskeleton-type suit developed for the neurorehabilitation of upper limb function. Several studies have addressed the usefulness of the robot; however, the appropriate patient selection remains unclear. In this study, we evaluated the effectiveness of the HAL-SJ exoskeleton in improving upper limb function in the subacute phase after a stroke, as a function of the severity of arm paralysis. Our analysis was based on a retrospective review of 35 patients, treated using the HAL-SJ exoskeleton in the subacute phase after their stroke, between October 2014 and December 2018. The severity of upper limb impairment was quantified using the Brunnstrom recovery stage (BRS) as follows: severe, BRS score 1–2, n = 10; moderate, BRS 3–4, n = 12; and mild, BRS 5–6, n = 13. The primary endpoint was the improvement in upper limb function, from baseline to post-intervention, measured using the Fugl-Meyer assessment upper limb motor score (ΔFMA-UE; range 0–66). The ΔFMA-UE score was significant for all three severity groups (P <0.05). The magnitude of improvement was greater in the moderate group than in the mild group (P <0.05). The greatest improvement was attained for patients with a moderate level of upper limb impairment at baseline. Our findings support the feasibility of the HAL-SJ to improve upper limb function in the subacute phase after a stroke with appropriate patient selection. This study is the first report showing the effect of robot-assisted rehabilitation using the HAL-SJ, according to the severity of paralysis in acute stroke patients with upper extremity motor deficits.

A case report on intensive, robot-assisted rehabilitation program for brainstem radionecrosis

INTRODUCTION

Radiotherapy is a valid treatment option for nasopharyngeal carcinoma. However, complications can occur following irradiation of the closest anatomical structures, including brainstem radionecrosis (BRN). The rehabilitation is poorly described in patients with BRN, despite its usefulness in improving functional independence in patients with brain tumors. We aimed at testing the usefulness of intensive, robot-assisted neurorehabilitation program to improve functional independence in a 57-year-old male with BRN.

PATIENT CONCERNS

A 57-year-old male diagnosed with a nasopharyngeal carcinoma, received a radiation total dose of 72 Gy. Owing to the appearance of a severe symptomatology characterized by dysphagia, hearing loss, and left sided hemiparesis, the patient was hospitalized to be provided with intensive pharmacological and neurorehabilitation treatment.

DIAGNOSIS

Follow-up brain magnetic resonance imaging disclosed no residual cancer, but some brainstem lesions compatible with BRN areas were appreciable.

INTERVENTION

The patient underwent a 2-month conventional, respiratory, and speech therapy. Given that the patient only mildly improved, he was provided with intensive robot-aided upper limb and gait training and virtual reality-based cognitive rehabilitation for other 2 months.

OUTCOMES

The patient reported a significant improvement in functional independence, spasticity, cognitive impairment degree, and balance.

CONCLUSION

Our case suggests the usefulness of neurorobotic intensive rehabilitation in BRN to reduce functional disability. Future studies should investigate whether an earlier, even multidisciplinary rehabilitative treatment could lead to better functional outcome in patients with BRN.

Increased gait variability during robot-assisted walking is accompanied by increased sensorimotor brain activity in healthy people

BACKGROUND

Gait disorders are major symptoms of neurological diseases affecting the quality of life. Interventions that restore walking and allow patients to maintain safe and independent mobility are essential. Robot-assisted gait training (RAGT) proved to be a promising treatment for restoring and improving the ability to walk. Due to heterogenuous study designs and fragmentary knowlegde about the neural correlates associated with RAGT and the relation to motor recovery, guidelines for an individually optimized therapy can hardly be derived. To optimize robotic rehabilitation, it is crucial to understand how robotic assistance affect locomotor control and its underlying brain activity. Thus, this study aimed to investigate the effects of robotic assistance (RA) during treadmill walking (TW) on cortical activity and the relationship between RA-related changes of cortical activity and biomechanical gait characteristics.

METHODS

Twelve healthy, right-handed volunteers (9 females; M = 25 ± 4 years) performed unassisted walking (UAW) and robot-assisted walking (RAW) trials on a treadmill, at 2.8 km/h, in a randomized, within-subject design. Ground reaction forces (GRFs) provided information regarding the individual gait patterns, while brain activity was examined by measuring cerebral hemodynamic changes in brain regions associated with the cortical locomotor network, including the sensorimotor cortex (SMC), premotor cortex (PMC) and supplementary motor area (SMA), using functional near-infrared spectroscopy (fNIRS).

RESULTS

A statistically significant increase in brain activity was observed in the SMC compared with the PMC and SMA (p < 0.05), and a classical double bump in the vertical GRF was observed during both UAW and RAW throughout the stance phase. However, intraindividual gait variability increased significantly with RA and was correlated with increased brain activity in the SMC (p = 0.05; r = 0.57).

CONCLUSIONS

On the one hand, robotic guidance could generate sensory feedback that promotes active participation, leading to increased gait variability and somatosensory brain activity. On the other hand, changes in brain activity and biomechanical gait characteristics may also be due to the sensory feedback of the robot, which disrupts the cortical network of automated walking in healthy individuals. More comprehensive neurophysiological studies both in laboratory and in clinical settings are necessary to investigate the entire brain network associated with RAW.

Computer Methods for Automatic Locomotion and Gesture Tracking in Mice and Small Animals for Neuroscience Applications: A Survey

Neuroscience has traditionally relied on manually observing laboratory animals in controlled environments. Researchers usually record animals behaving freely or in a restrained manner and then annotate the data manually. The manual annotation is not desirable for three reasons; (i) it is time-consuming, (ii) it is prone to human errors, and (iii) no two human annotators will 100% agree on annotation, therefore, it is not reproducible. Consequently, automated annotation for such data has gained traction because it is efficient and replicable. Usually, the automatic annotation of neuroscience data relies on computer vision and machine learning techniques. In this article, we have covered most of the approaches taken by researchers for locomotion and gesture tracking of specific laboratory animals, i.e. rodents. We have divided these papers into categories based upon the hardware they use and the software approach they take. We have also summarized their strengths and weaknesses.

Current State and Future Prospects of EEG and fNIRS in Robot-Assisted Gait Rehabilitation: A Brief Review

Gait and balance impairments are frequently considered as the most significant concerns among individuals suffering from neurological diseases. Robot-assisted gait training (RAGT) has shown to be a promising neurorehabilitation intervention to improve gait recovery in patients following stroke or brain injury by potentially initiating neuroplastic changes. However, the neurophysiological processes underlying gait recovery through RAGT remain poorly understood. As non-invasive, portable neuroimaging techniques, electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) provide new insights regarding the neurophysiological processes occurring during RAGT by measuring different perspectives of brain activity. Due to spatial information about changes in cortical activation patterns and the rapid temporal resolution of bioelectrical changes, more features correlated with brain activation and connectivity can be identified when using fused EEG-fNIRS, thus leading to a detailed understanding of neurophysiological mechanisms underlying motor behavior and impairments due to neurological diseases. Therefore, multi-modal integrations of EEG-fNIRS appear promising for the characterization of neurovascular coupling in brain network dynamics induced by RAGT. In this brief review, we surveyed neuroimaging studies focusing specifically on robotic gait rehabilitation. While previous studies have examined either EEG or fNIRS with respect to RAGT, a multi-modal integration of both approaches is lacking. Based on comparable studies using fused EEG-fNIRS integrations either for guiding non-invasive brain stimulation or as part of brain-machine interface paradigms, the potential of this methodologically combined approach in RAGT is discussed. Future research directions and perspectives for targeted, individualized gait recovery that optimize the outcome and efficiency of RAGT in neurorehabilitation were further derived.

The effect of stride length on lower extremity joint kinetics at various gait speeds

Robot-assisted training is a promising tool under development for improving walking function based on repetitive goal-oriented task practice. The challenges in developing the controllers for gait training devices that promote desired changes in gait is complicated by the limited understanding of the human response to robotic input. A possible method of controller formulation can be based on the principle of bio-inspiration, where a robot is controlled to apply the change in joint moment applied by human subjects when they achieve a gait feature of interest. However, it is currently unclear how lower extremity joint moments are modulated by even basic gait spatio-temporal parameters. In this study, we investigated how sagittal plane joint moments are affected by a factorial modulation of two important gait parameters: gait speed and stride length. We present the findings obtained from 20 healthy control subjects walking at various treadmill-imposed speeds and instructed to modulate stride length utilizing real-time visual feedback. Implementing a continuum analysis of inverse-dynamics derived joint moment profiles, we extracted the effects of gait speed and stride length on joint moment throughout the gait cycle. Moreover, we utilized a torque pulse approximation analysis to determine the timing and amplitude of torque pulses that approximate the difference in joint moment profiles between stride length conditions, at all gait speed conditions. Our results show that gait speed has a significant effect on the moment profiles in all joints considered, while stride length has more localized effects, with the main effect observed on the knee moment during stance, and smaller effects observed for the hip joint moment during swing and ankle moment during the loading response. Moreover, our study demonstrated that trailing limb angle, a parameter of interest in programs targeting propulsion at push-off, was significantly correlated with stride length. As such, our study has generated assistance strategies based on pulses of torque suitable for implementation via a wearable exoskeleton with the objective of modulating stride length, and other correlated variables such as trailing limb angle.

Human social motor solutions for human-machine interaction in dynamical task contexts

Multiagent activity is commonplace in everyday life and can improve the behavioral efficiency of task performance and learning. Thus, augmenting social contexts with the use of interactive virtual and robotic agents is of great interest across health, sport, and industry domains. However, the effectiveness of human-machine interaction (HMI) to effectively train humans for future social encounters depends on the ability of artificial agents to respond to human coactors in a natural, human-like manner. One way to achieve effective HMI is by developing dynamical models utilizing dynamical motor primitives (DMPs) of human multiagent coordination that not only capture the behavioral dynamics of successful human performance but also, provide a tractable control architecture for computerized agents. Previous research has demonstrated how DMPs can successfully capture human-like dynamics of simple nonsocial, single-actor movements. However, it is unclear whether DMPs can be used to model more complex multiagent task scenarios. This study tested this human-centered approach to HMI using a complex dyadic shepherding task, in which pairs of coacting agents had to work together to corral and contain small herds of virtual sheep. Human-human and human-artificial agent dyads were tested across two different task contexts. The results revealed (i) that the performance of human-human dyads was equivalent to those composed of a human and the artificial agent and (ii) that, using a "Turing-like" methodology, most participants in the HMI condition were unaware that they were working alongside an artificial agent, further validating the isomorphism of human and artificial agent behavior.

Brain-machine interfaces for rehabilitation in stroke: A review

BACKGROUND

Motor paralysis after stroke has devastating consequences for the patients, families and caregivers. Although therapies have improved in the recent years, traditional rehabilitation still fails in patients with severe paralysis. Brain-machine interfaces (BMI) have emerged as a promising tool to guide motor rehabilitation interventions as they can be applied to patients with no residual movement.

OBJECTIVE

This paper reviews the efficiency of BMI technologies to facilitate neuroplasticity and motor recovery after stroke.

METHODS

We provide an overview of the existing rehabilitation therapies for stroke, the rationale behind the use of BMIs for motor rehabilitation, the current state of the art and the results achieved so far with BMI-based interventions, as well as the future perspectives of neural-machine interfaces.

RESULTS

Since the first pilot study by Buch and colleagues in 2008, several controlled clinical studies have been conducted, demonstrating the efficacy of BMIs to facilitate functional recovery in completely paralyzed stroke patients with noninvasive technologies such as the electroencephalogram (EEG).

CONCLUSIONS

Despite encouraging results, motor rehabilitation based on BMIs is still in a preliminary stage, and further improvements are required to boost its efficacy. Invasive and hybrid approaches are promising and might set the stage for the next generation of stroke rehabilitation therapies.

Translational effects of robot-mediated therapy in subacute stroke patients: an experimental evaluation of upper limb motor recovery

Robot-mediated therapies enhance the recovery of post-stroke patients with motor deficits. Repetitive and repeatable exercises are essential for rehabilitation following brain damage or other disorders that impact the central nervous system, as plasticity permits to reorganize its neural structure, fostering motor relearning. Despite the fact that so many studies claim the validity of robot-mediated therapy in post-stroke patient rehabilitation, it is still difficult to assess to what extent its adoption improves the efficacy of traditional therapy in daily life, and also because most of the studies involved planar robots. In this paper, we report the effects of a 20-session-rehabilitation project involving the Armeo Power robot, an assistive exoskeleton to perform 3D upper limb movements, in addition to conventional rehabilitation therapy, on 10 subacute stroke survivors. Patients were evaluated through clinical scales and a kinematic assessment of the upper limbs, both pre- and post-treatment. A set of indices based on the patients' 3D kinematic data, gathered from an optoelectronic system, was calculated. Statistical analysis showed a remarkable difference in most parameters between pre- and post-treatment. Significant correlations between the kinematic parameters and clinical scales were found. Our findings suggest that 3D robot-mediated rehabilitation, in addition to conventional therapy, could represent an effective means for the recovery of upper limb disability. Kinematic assessment may represent a valid tool for objectively evaluating the efficacy of the rehabilitation treatment.

Stroke lesion location influences the decoding of movement intention from EEG

Recent studies have demonstrated the efficacy of brain-machine interfaces (BMI) for motor rehabilitation after stroke, especially for those patients with severe paralysis. However, a cerebro-vascular accident can affect the brain in many different manners, and lesions in diverse areas, even from significantly different volumes, can lead to similar or equal motor deficits. The location of the insult influences the way the brain activates when moving or attempting to move a paralyzed limb. Since the essence of a rehabilitative BMI is to precisely decode motor commands from the brain, it is crucial to characterize how lesion location affects the measured signals and if and how it influences BMI performance. This paper compares the performances of an electroencephalography (EEG)-based movement intention decoder in two groups of severely paralyzed chronic stroke patients: 14 with subcortical lesions and 14 with mixed (i.e., cortical and subcortical) lesions. We show that the lesion location influences the performance of the BMI when decoding the movement attempts of the paretic arm. The obtained results underline the need for further developments for a better individualization of BMI-based rehabilitative therapies for stroke patients.

Exoskeleton-Robot Assisted Therapy in Stroke Patients: A Lesion Mapping Study

Background: Technology-supported rehabilitation is emerging as a solution to support therapists in providing a high-intensity, repetitive and task-specific treatment, aimed at improving stroke recovery. End-effector robotic devices are known to positively affect the recovery of arm functions, however there is a lack of evidence regarding exoskeletons. This paper evaluates the impact of cerebral lesion load on the response to a validated robotic-assisted rehabilitation protocol.

Methods: Fourteen hemiparetic patients were assessed in a within-subject design (age 66.9 ± 11.3 years; 10 men and 4 women). Patients, in post-acute phase, underwent 7 weeks of bilateral arm training assisted by an exoskeleton robot combined with a conventional treatment (consisting of simple physical activity together with occupational therapy). Clinical and neuroimaging evaluations were performed immediately before and after rehabilitation treatments. Fugl-Meyer (FM) and Motricity Index (MI) were selected to measure primary outcomes, i.e., motor function and strength. Functional independance measure (FIM) and Barthel Index were selected to measure secondary outcomes, i.e., daily living activities. Voxel-based lesion symptom mapping (VLSM) was used to determine the degree of cerebral lesions associated with motor recovery.

Results: Robot-assisted rehabilitation was effective in improving upper limb motor function recovery, considering both primary and secondary outcomes. VLSM detected that lesion load in the superior region of the corona radiata, internal capsule and putamen were significantly associated with recovery of the upper limb as defined by the FM scores (p-level < 0.01).

Conclusions: The probability of functional recovery from stroke by means of exoskeleton robotic rehabilitation relies on the integrity of specific subcortical regions involved in the primary motor pathway. This is consistent with previous evidence obtained with conventional neurorehabilitation approaches.

Classification of different reaching movements from the same limb using EEG

OBJECTIVE

Brain-computer-interfaces (BCIs) have been proposed not only as assistive technologies but also as rehabilitation tools for lost functions. However, due to the stochastic nature, poor spatial resolution and signal to noise ratio from electroencephalography (EEG), multidimensional decoding has been the main obstacle to implement non-invasive BCIs in real-live rehabilitation scenarios. This study explores the classification of several functional reaching movements from the same limb using EEG oscillations in order to create a more versatile BCI for rehabilitation.

APPROACH

Nine healthy participants performed four 3D center-out reaching tasks in four different sessions while wearing a passive robotic exoskeleton at their right upper limb. Kinematics data were acquired from the robotic exoskeleton. Multiclass extensions of Filter Bank Common Spatial Patterns (FBCSP) and a linear discriminant analysis (LDA) classifier were used to classify the EEG activity into four forward reaching movements (from a starting position towards four target positions), a backward movement (from any of the targets to the starting position and rest). Recalibrating the classifier using data from previous or the same session was also investigated and compared.

MAIN RESULTS

Average EEG decoding accuracy were significantly above chance with 67%, 62.75%, and 50.3% when decoding three, four and six tasks from the same limb, respectively. Furthermore, classification accuracy could be increased when using data from the beginning of each session as training data to recalibrate the classifier.

SIGNIFICANCE

Our results demonstrate that classification from several functional movements performed by the same limb is possible with acceptable accuracy using EEG oscillations, especially if data from the same session are used to recalibrate the classifier. Therefore, an ecologically valid decoding could be used to control assistive or rehabilitation mutli-degrees of freedom (DoF) robotic devices using EEG data. These results have important implications towards assistive and rehabilitative neuroprostheses control in paralyzed patients.

Robotic-assisted gait training combined with transcranial direct current stimulation in chronic stroke patients: A pilot double-blind, randomized controlled trial

BACKGROUND

Although robotic-assisted gait training (RAGT) is becoming a standard method in stroke rehabilitation, its effect on chronic stroke patients is uncertain.

OBJECTIVE

This study aimed to investigate whether anodal transcranial direct current stimulation (tDCS) enhances the effect of RAGT on functional ambulation in chronic stroke patients.

METHODS

Chronic hemiplegic stroke patients with a Functional Ambulatory Category (FAC) score≤4 were randomly assigned to either the RAGT with anodal tDCS (Anodal) group the sham tDCS (Sham) group. The patients were provided with RAGT for 45 min after allocated tDCS on the leg motor cortex in the impaired hemisphere for 20 min every weekday for 2 weeks. The primary outcome measure was the FAC, and the secondary outcome measures included 10-m walking test, 6-min walking test, Berg Balance Scale, Fugl-Meyer assessment of the lower extremity, Medical Research Council Scale, and motor-evoked potential (MEP) parameters. They were evaluated before treatment (T0), immediately after treatment (T1), and 4 weeks after the end of treatment (T2).

RESULTS

Twenty-one patients were finally included. The percentage of participants who achieved improvement in the FAC score was greater in the Anodal group than in the Sham group, and the difference was significant at T2 (66.7% vs. 12.5%, p = 0.024). In secondary outcome measures, the Anodal group showed greater improvement in the 6-min walking test than the Sham group at T2 (56.49±38.87 vs. 23.59±17.00, p = 0.038). The changes in the MEP parameters were not significantly different between the two groups.

CONCLUSION

This pilot study suggested that anodal tDCS on the leg motor cortex in the impaired hemisphere may facilitate the effect of RAGT on functional ambulation in chronic stroke patients. Larger clinical trials will be needed to confirm the effect of RAGT combined with tDCS in chronic stroke patients based on the present study.

Shaping neuroplasticity by using powered exoskeletons in patients with stroke: a randomized clinical trial

BACKGROUND

The use of neurorobotic devices may improve gait recovery by entraining specific brain plasticity mechanisms, which may be a key issue for successful rehabilitation using such approach. We assessed whether the wearable exoskeleton, Ekso™, could get higher gait performance than conventional overground gait training (OGT) in patients with hemiparesis due to stroke in a chronic phase, and foster the recovery of specific brain plasticity mechanisms.

METHODS

We enrolled forty patients in a prospective, pre-post, randomized clinical study. Twenty patients underwent Ekso™ gait training (EGT) (45-min/session, five times/week), in addition to overground gait therapy, whilst 20 patients practiced an OGT of the same duration. All individuals were evaluated about gait performance (10 m walking test), gait cycle, muscle activation pattern (by recording surface electromyography from lower limb muscles), frontoparietal effective connectivity (FPEC) by using EEG, cortico-spinal excitability (CSE), and sensory-motor integration (SMI) from both primary motor areas by using Transcranial Magnetic Stimulation paradigm before and after the gait training.

RESULTS

A significant effect size was found in the EGT-induced improvement in the 10 m walking test (d = 0.9, p < 0.001), CSE in the affected side (d = 0.7, p = 0.001), SMI in the affected side (d = 0.5, p = 0.03), overall gait quality (d = 0.8, p = 0.001), hip and knee muscle activation (d = 0.8, p = 0.001), and FPEC (d = 0.8, p = 0.001). The strengthening of FPEC (r = 0.601, p < 0.001), the increase of SMI in the affected side (r = 0.554, p < 0.001), and the decrease of SMI in the unaffected side (r = - 0.540, p < 0.001) were the most important factors correlated with the clinical improvement.

CONCLUSIONS

Ekso™ gait training seems promising in gait rehabilitation for post-stroke patients, besides OGT. Our study proposes a putative neurophysiological basis supporting Ekso™ after-effects. This knowledge may be useful to plan highly patient-tailored gait rehabilitation protocols.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT03162263 .

Quantification of Upper Limb Motor Recovery and EEG Power Changes after Robot-Assisted Bilateral Arm Training in Chronic Stroke Patients: A Prospective Pilot Study

Background

Bilateral arm training (BAT) has shown promise in expediting progress toward upper limb recovery in chronic stroke patients, but its neural correlates are poorly understood.

Objective

To evaluate changes in upper limb function and EEG power after a robot-assisted BAT in chronic stroke patients.

Methods

In a within-subject design, seven right-handed chronic stroke patients with upper limb paresis received 21 sessions (3 days/week) of the robot-assisted BAT. The outcomes were changes in score on the upper limb section of the Fugl-Meyer assessment (FM), Motricity Index (MI), and Modified Ashworth Scale (MAS) evaluated at the baseline (T₀), posttraining (T₁), and 1-month follow-up (T₂). Event-related desynchronization/synchronization were calculated in the upper alpha and the beta frequency ranges.

Results

Significant improvement in all outcomes was measured over the course of the study. Changes in FM were significant at T₂, and in MAS at T₁ and T₂. After training, desynchronization on the ipsilesional sensorimotor areas increased during passive and active movement, as compared with T₀.

Conclusions

A repetitive robotic-assisted BAT program may improve upper limb motor function and reduce spasticity in the chronically impaired paretic arm. Effects on spasticity were associated with EEG changes over the ipsilesional sensorimotor network.

Combined transcranial direct current stimulation and robotic upper limb therapy improves upper limb function in an adult with cerebral palsy

BACKGROUND: Robotic therapy can improve upper limb function in hemiparesis. Excitatory transcranial direct current stimulation (tDCS) can prime brain motor circuits before therapy.

OBJECTIVE: We tested safety and efficacy of tDCS plus robotic therapy in an adult with unilateral spastic cerebral palsy (USCP).

METHODS: In each of 36 sessions, anodal tDCS (2 mA, 20 min) was applied over the motor map of the affected hand. Immediately after tDCS, the participant completed robotic therapy, using the shoulder, elbow, and wrist (MIT Manus). The participant sat in a padded chair with affected arm abducted, forearm supported, and hand grasping the robot handle. The participant controlled the robot arm with his affected arm to move a cursor from the center of a circle to each of eight targets (960 movements). Motor function was tested before, after, and six months after therapy with the Wolf Motor Function Test (WMFT) and Fugl-Meyer (FM).

RESULTS: Reaching accuracy on the robot task improved significantly after therapy. The WMFT and FM improved clinically meaningful amounts after therapy. The motor map of the affected hand expanded after therapy. Improvements were maintained six months after therapy.

CONCLUSIONS: Combined tDCS and robotics safely improved upper limb function in an adult with USCP.