Exoskeleton Training Research Articles

Upper limb motor improvement in chronic stroke after combining botulinum toxin A injection and multi-joints robot-assisted therapy: a case report.

Spasticity is one of the major complications after stroke. Botulinum toxin type A (BoNT-A) injection is commonly used to manage focal spasticity. However, it is uncertain whether BoNT-A can improve activities of daily living function of paretic arm. The recovery of functions of the affected arm is also the aim of robotic upper limb (UL) therapy. The motorized exoskeleton assists the patient in a large 3D work environment by promoting movement for the UL (shoulder, elbow, wrist, hand). The combination of the BoNT-A injection and the robotic therapy might enhance functional recovery after stroke. We reported the case of a chronic stroke patient in which the injection of BoNT-A was combined with multi-joint exoskeleton training. The patient showed improvement in the motor control of the UL, supporting the feasibility of this approach.

O-08 Brain connectivity modulation after exoskeleton gait in chronic stroke survivors: a pilot study

Background Restoration of independent gait after stroke is a principal goal of survivors. Exoskeleton overground gait training provides trunk support and inter-limb coordination based on fine-tuning of the robot control parameters. The aim of our study was to identify short-term plasticity based on electroencephalography (EEG) data induced by a single trial of exoskeleton gait training in unilateral hemiplegic stroke survivors. Material and methods 64-channel EEG was recorded before gait (T0), after overground walking (T1) and after overground exoskeleton (EksoGT) gait training (T2) in 9 stroke survivors. Relative power and coherence were estimated for alpha1 (8–10 Hz), alpha2 (10.5–12.5 Hz) and beta (13–30 Hz) frequency ranges. Graph analysis assessed network model properties: node strength (S) and betweenness centrality (BC). Results Left-hemisphere stroke subjects showed S decrease over anterior and posterior cortex in alpha1, alpha2 and beta at T1 and T2. BC decreased at vertex at T1 and T2 in alpha2 and beta. Right-hemisphere stroke subjects displayed power decrease after exoskeleton walking in alpha2 over CPZ and CP2, and in beta over left contralateral sensorimotor cortex (cSM) and right ipsilateral prefrontal cortex (iPFC). S increased in alpha1 and alpha2 over cSM and iPFC at T2; BC decreased in alpha2 over iPFC at T2 compared to T1. Conclusions A single session of tailored exoskeleton training provides short-term neuroplastic modulation in chronic stroke. Right-hemisphere stroke subjects re-establish a more physiological activation network; a similar reorganization does not take place in left-hemisphere stroke subjects, supporting the role of lateralization in limb control and stroke recovery.

Dissociating motor learning from recovery in exoskeleton training post-stroke

BackgroundA large number of robotic or gravity-supporting devices have been developed for rehabilitation of upper extremity post-stroke. Because these devices continuously monitor performance data during training, they could potentially help to develop predictive models of the effects of motor training on recovery. However, during training with such devices, patients must become adept at using the new “tool” of the exoskeleton, including learning the new forces and visuomotor transformations associated with the device. We thus hypothesized that the changes in performance during extensive training with a passive, gravity-supporting, exoskeleton device (the Armeo Spring) will follow an initial fast phase, due to learning to use the device, and a slower phase that corresponds to reduction in overall arm impairment. Of interest was whether these fast and slow processes were related.MethodsTo test the two-process hypothesis, we used mixed-effect exponential models to identify putative fast and slow changes in smoothness of arm movements during 80 arm reaching tests performed during 20 days of exoskeleton training in 53 individuals with post-acute stroke.ResultsIn line with our hypothesis, we found that double exponential models better fit the changes in smoothness of arm movements than single exponential models. In contrast, single exponential models better fit the data for a group of young healthy control subjects. In addition, in the stroke group, we showed that smoothness correlated with a measure of impairment (the upper extremity Fugl Meyer score - UEFM) at the end, but not at the beginning, of training. Furthermore, the improvement in movement smoothness due to the slow component, but not to the fast component, strongly correlated with the improvement in the UEFM between the beginning and end of training. There was no correlation between the change of peaks due to the fast process and the changes due to the slow process. Finally, the improvement in smoothness due to the slow, but not the fast, component correlated with the number of days since stroke at the onset of training – i.e. participants who started exoskeleton training sooner after stroke improved their smoothness more.ConclusionsOur results therefore demonstrate that at least two processes are involved in in performance improvements measured during mechanized training post-stroke. The fast process is consistent with learning to use the exoskeleton, while the slow process independently reflects the reduction in upper extremity impairment.

Ranking Importance of Exoskeleton Design Aspects

The objective of this research project was to determine what a conglomerate of professionals consider as the most important metrics to consider when designing an exoskeleton for training. Over 400 researchers, engineers, and scientists were polled in a ranked order survey covering more than 50 different aspects in engineering design. These aspects were identified from a cogent literature review for consideration. While there are a slew of papers covering the results of exoskeleton designs as posture support mechanisms, rehabilitation mechanisms, tools to assist or replace body functions, and human performance augmentation, few cover what aspects were considered in the engineering design phase.

Effects of Exoskeleton Training Intervention on Net Loading Force in Chronic Spinal Cord Injury.

The goal of this study was to understand the rehabilitative effects of longitudinal overground exoskeleton training $( >100$ hours) on gait mechanics, especially foot loading, for gains in walking speed in an individual with chronic motorincomplete SCI. Biomechanical measures included: normalized plantar loading forces, walking speed and bilateral weight transfer ratio during walking in the EksoGT $^{\mathrm{ TM}}$ exoskeleton. Longitudinal training with a robotic exoskeleton yielded improvements in clinical outcomes (AIS classification, ISNCSCI motor scores and 10MWT) and provided functional gains in terms of biomechanical outcomes (plantar forces, weight transfer point) to increase overall walking speed.

Mechanisms for improving walking speed after longitudinal powered robotic exoskeleton training for individuals with spinal cord injury.

The goal of this study was to establish strideparameter gait models correlated to speed on individuals with chronic SCI and able-bodied controls walking with a powered robotic exoskeleton (EksoGT $^{\mathrm{ TM}}$). Longitudinal exoskeleton training $( >100$ hours) across eight individuals with SCI resulted in a 30% increase in walking speed. A simple linear regression between step length, stride length for given speed were very tightly correlated along a line of best fit $( \mathrm {p}<$.001). The temporal parameters of stride time, stance time and double support time depicted a non-linear exponentially decaying relationship for given walking speed. The research findings indicate that although longitudinal exoskeleton training reduces the temporal parameters, increases in spatial parameters are only marginal.

Hybrid Assistive Limb Exoskeleton HAL in the Rehabilitation of Chronic Spinal Cord Injury: Proof of Concept; the Results in 21 Patients.

The use of mobile exoskeletons is becoming more and more common in the field of spinal cord injury (SCI) rehabilitation. The hybrid assistive limb (HAL) exoskeleton provides a tailored support depending on the patient's voluntary drive. After a pilot study in 2014 that included 8 patients with chronic SCI, this study of 21 patients with chronic SCI serves as a proof of concept. It was conducted to provide further evidence regarding the efficacy of exoskeletal-based rehabilitation. Functional assessment included walking speed, distance, and time on a treadmill, with additional analysis of functional mobility using the following tests: 10-meter walk test (10MWT), timed up and go (TUG) test, 6-minute walk test (6MWT), and the walking index for SCI II (WISCI-II) score. After a training period of 90 days, all 21 patients significantly improved their functional and ambulatory mobility without the exoskeleton. Patients were assessed by the 6MWT, the TUG test, and the 10MWT, which also indicated an increase in the WISCI-II score along with significant improvements in HAL-associated walking speed, distance, and time. Although, exoskeletons are not yet an established treatment in the rehabilitation of spinal cord injuries, the devices will play a more important role in the future. The HAL exoskeleton training enables effective, body weight-supported treadmill training and is capable of improving ambulatory mobility. Future controlled studies are required to enable a comparison of the new advances in the field of SCI rehabilitation with traditional over-ground training.

A Framework for Measuring the Progress in Exoskeleton Skills in People with Complete Spinal Cord Injury.

For safe application of exoskeletons in people with spinal cord injury at home or in the community, it is required to have completed an exoskeleton training in which users learn to perform basic and advanced skills. So far, a framework to test exoskeleton skills is lacking. The aim of this study was to develop and test the hierarchy and reliability of a framework for measuring the progress in the ability to perform basic and advanced skills. Twelve participants with paraplegia were given twenty-four training sessions in 8 weeks with the Rewalk-exoskeleton. During the 2nd, 4th, and 6th training week the Intermediate-skills-test was performed consisting of 27 skills, measured in an hierarchical order of difficulty, until two skills were not achieved. When participants could walk independently, the Final-skills-test, consisting of 20 skills, was performed in the last training session. Each skill was performed at least two times with a maximum of three attempts. As a reliability measure the consistency was used, which was the number of skills performed the same in the first two attempts relative to the total number. Ten participants completed the training program. Their number of achieved intermediate skills was significantly different between the measurements XF2(2) = 12.36, p = 0.001. Post-hoc analysis revealed a significant increase in the median achieved intermediate skills from 4 [1–7] at the first to 10.5 [5–26] at the third Intermediate-skills-test. The rate of participants who achieved the intermediate skills decreased and the coefficient of reproducibility was 0.98. Eight participants met the criteria to perform the Final-skills-test. Their median number of successfully performed final skills was 16.5 [13–20] and 17 [14–19] skills in the first and second time. The overall consistency of >70% was achieved in the Intermediate-skills-test (73%) and the Final-skills-test (81%). Eight out of twelve participants experienced skin damage during the training, in four participants this resulted in missed training sessions. The framework proposed in this study measured the progress in performing basic and advanced exoskeleton skills during a training program. The hierarchical ordered skills-test could discriminate across participants' skill-level and the overall consistency was considered acceptable.

Gait training after spinal cord injury: safety, feasibility and gait function following 8 weeks of training with the exoskeletons from Ekso Bionics.

Prospective quasi-experimental study, pre- and post-design. Assess safety, feasibility, training characteristics and changes in gait function for persons with spinal cord injury (SCI) using the robotic exoskeletons from Ekso Bionics. Nine European rehabilitation centres. Robotic exoskeleton gait training, three times weekly over 8 weeks. Time upright, time walking and steps in the device (training characteristics) were recorded longitudinally. Gait and neurological function were measured by 10 Metre Walk Test (10 MWT), Timed Up and Go (TUG), Berg Balance Scale (BBS), Walking Index for Spinal Cord Injury (WISCI) II and Lower Extremity Motor Score (LEMS). Fifty-two participants completed the training protocol. Median age: 35.8 years (IQR 27.5-52.5), men/women: N = 36/16, neurological level of injury: C1-L2 and severity: AIS A-D (American Spinal Injury Association Impairment Scale). Time since injury (TSI) < 1 year, N = 25; > 1 year, N = 27. No serious adverse events occurred. Three participants dropped out following ankle swelling (overuse injury). Four participants sustained a Category II pressure ulcer at contact points with the device but completed the study and skin normalized. Training characteristics increased significantly for all subgroups. The number of participants with TSI < 1 year and gait function increased from 20 to 56% (P = 0.004) and 10MWT, TUG, BBS and LEMS results improved (P < 0.05). The number of participants with TSI > 1 year and gait function, increased from 41 to 44% and TUG and BBS results improved (P < 0.05). Exoskeleton training was generally safe and feasible in a heterogeneous sample of persons with SCI. Results indicate potential benefits on gait function and balance.

Effects of Exoskeleton Training Intervention on Net Loading Force Profile for SCI: A Case Study

Effects of Exoskeleton Training Intervention on Net Loading Force Profile for SCI: A Case Study

ARCTiC LawE: An Upper-Body Exoskeleton for Firearm Training

The Armed Robotic Control for Training in Civilian Law Enforcement, or ARCTiC LawE, is an upper-body exoskeleton designed to assist civilian, military, and law enforcement personnel in accurate, precise, and reliable handgun techniques. This exoskeleton training utilizes a laser-based handgun with similar dimensions, trigger pull, and break action to a Glock® 19 pistol, common to both public and private security sectors. The paper aims to train and test subjects with no handgun training/experience both with and without the ARCTiC LawE and compare the results of accuracy, precision, and speed. Ultimately, the exoskeleton greatly impacts sensory motor learning, and the biomechanical implications are confirmed via both performance and physiological measurements. The researchers believe the ARCTiC LawE is a viable substitute for training with live-fire handguns in order to reduce the cost of training time and munitions. They also believe the ARCTiC LawE will increase accuracy and precision for typical law enforcement and military live-fire drills. Additionally, this paper increases the breadth of knowledge for exoskeletons as a tool for training.

The Effectiveness and Safety of Exoskeletons as Assistive and Rehabilitation Devices in the Treatment of Neurologic Gait Disorders in Patients with Spinal Cord Injury: A Systematic Review.

Study Design Systematic review. Clinical Questions (1) When used as an assistive device, do wearable exoskeletons improve lower extremity function or gait compared with knee-ankle-foot orthoses (KAFOs) in patients with complete or incomplete spinal cord injury? (2) When used as a rehabilitation device, do wearable exoskeletons improve lower extremity function or gait compared with other rehabilitation strategies in patients with complete or incomplete spinal cord injury? (3) When used as an assistive or rehabilitation device, are wearable exoskeletons safe compared with KAFO for assistance or other rehabilitation strategies for rehabilitation in patients with complete or incomplete spinal cord injury? Methods PubMed, Cochrane, and Embase databases and reference lists of key articles were searched from database inception to May 2, 2016, to identify studies evaluating the effectiveness of wearable exoskeletons used as assistive or rehabilitative devices in patients with incomplete or complete spinal cord injury. Results No comparison studies were found evaluating exoskeletons as an assistive device. Nine comparison studies (11 publications) evaluated the use of exoskeletons as a rehabilitative device. The 10-meter walk test velocity and Spinal Cord Independence Measure scores showed no difference in change from baseline among patients undergoing exoskeleton training compared with various comparator therapies. The remaining primary outcome measures of 6-minute walk test distance and Walking Index for Spinal Cord Injury I and II and Functional Independence Measure–Locomotor scores showed mixed results, with some studies indicating no difference in change from baseline between exoskeleton training and comparator therapies, some indicating benefit of exoskeleton over comparator therapies, and some indicating benefit of comparator therapies over exoskeleton. Conclusion There is no data to compare locomotion assistance with exoskeleton versus conventional KAFOs. There is no consistent benefit from rehabilitation using an exoskeleton versus a variety of conventional methods in patients with chronic spinal cord injury. Trials comparing later-generation exoskeletons are needed.

Exoskeleton Training Improves Parameters of Physical Activity in a Person with Tetraplegia

The American College of Sports Medicine recommends 30 minutes per day of exercise training to reduce cardio-metabolic risk factors in the general population. We have previously shown that the exoskeleton (Ekso) improves level of physical activity in three persons with spinal cord injury (SCI) following 8 weeks of training. The purpose of the current case report is to determine whether exoskeleton training can improve level of physical activity in a person with a complete C5-C6 tetraplegia.

Clinical effectiveness and safety of powered exoskeleton-assisted walking in patients with spinal cord injury: systematic review with meta-analysis.

BackgroundPowered exoskeletons are designed to safely facilitate ambulation in patients with spinal cord injury (SCI). We conducted the first meta-analysis of the available published research on the clinical effectiveness and safety of powered exoskeletons in SCI patients.MethodsMEDLINE and EMBASE databases were searched for studies of powered exoskeleton-assisted walking in patients with SCI. Main outcomes were analyzed using fixed and random effects meta-analysis models.ResultsA total of 14 studies (eight ReWalk™, three Ekso™, two Indego®, and one unspecified exoskeleton) representing 111 patients were included in the analysis. Training programs were typically conducted three times per week, 60–120 minutes per session, for 1–24 weeks. Ten studies utilized flat indoor surfaces for training and four studies incorporated complex training, including walking outdoors, navigating obstacles, climbing and descending stairs, and performing activities of daily living. Following the exoskeleton training program, 76% of patients were able to ambulate with no physical assistance. The weighted mean distance for the 6-minute walk test was 98 m. The physiologic demand of powered exoskeleton-assisted walking was 3.3 metabolic equivalents and rating of perceived exertion was 10 on the Borg 6–20 scale, comparable to self-reported exertion of an able-bodied person walking at 3 miles per hour. Improvements in spasticity and bowel movement regularity were reported in 38% and 61% of patients, respectively. No serious adverse events occurred. The incidence of fall at any time during training was 4.4%, all occurring while tethered using a first-generation exoskeleton and none resulting in injury. The incidence of bone fracture during training was 3.4%. These risks have since been mitigated with newer generation exoskeletons and refinements to patient eligibility criteria.ConclusionPowered exoskeletons allow patients with SCI to safely ambulate in real-world settings at a physical activity intensity conducive to prolonged use and known to yield health benefits.

Exoskeleton Training Improves Level of Physical Activity after Spinal Cord Injury

The American College of Sports Medicine recommends 30 minutes per day of exercise training to reduce cardio-metabolic risk factors in the general population. Greater daily physical activity time is associated with lower chronic disease risk in adults with spinal cord injury (SCI). The purpose of the current case series is to determine whether Exoskeleton training can improve level of physical activity as determined by the duration of walking.

Does tandem walking discriminate better than normal walking among children with DCD, ataxia and healthy controls? A preliminary analysis performed with IMUs on the trunk

[1] Mehrholz J, Haedrich A, Platz T, Kugler J, Pohl M. Electromechanical and robotassisted arm training for improving generic activities of daily living, arm function, and arm muscle strength after stroke. The Cochrane Library; 2012. [2] Frisoli A, ProcopioC, Chisari C, Creatini I, Bonfiglio L, BergamascoM, et al. Positive effects of robotic exoskeleton training of upper limb reaching movements after stroke. J Neuroeng Rehabil 2012;9(1):36. [3] Liao WW, Wu CY, Hsieh YW, Lin KC, Chang WY. Effects of robot-assisted upper limb rehabilitation ondaily function and real-world armactivity in patientswith chronic stroke: a randomized controlled trial. Clin Rehabil 2012;26(2):111–20.

HAL® exoskeleton training improves walking parameters and normalizes cortical excitability in primary somatosensory cortex in spinal cord injury patients.

BackgroundReorganization in the sensorimotor cortex accompanied by increased excitability and enlarged body representations is a consequence of spinal cord injury (SCI). Robotic-assisted bodyweight supported treadmill training (BWSTT) was hypothesized to induce reorganization and improve walking function.ObjectiveTo assess whether BWSTT with hybrid assistive limb® (HAL®) exoskeleton affects cortical excitability in the primary somatosensory cortex (S1) in SCI patients, as measured by paired-pulse somatosensory evoked potentials (ppSEP) stimulated above the level of injury.MethodsEleven SCI patients took part in HAL® assisted BWSTT for 3 months. PpSEP were conducted before and after this training period, where the amplitude ratios (SEP amplitude following double pulses - SEP amplitude following single pulses) were assessed and compared to eleven healthy control subjects. To assess improvement in walking function, we used the 10-m walk test, timed-up-and-go test, the 6-min walk test, and the lower extremity motor score.ResultsPpSEPs were significantly increased in SCI patients as compared to controls at baseline. Following training, ppSEPs were increased from baseline and no longer significantly differed from controls. Walking parameters also showed significant improvements, yet there was no significant correlation between ppSEP measures and walking parameters.ConclusionsThe findings suggest that robotic-assisted BWSTT with HAL® in SCI patients is capable of inducing cortical plasticity following highly repetitive, active locomotive use of paretic legs. While there was no significant correlation of excitability with walking parameters, brain areas other than S1 might reflect improvement of walking functions. EEG and neuroimaging studies may provide further information about supraspinal plastic processes and foci in SCI rehabilitation.

Lower-limb exoskeletons for individuals with chronic spinal cord injury: findings from a feasibility study

Objective: To assess the feasibility of conducting a well-powered trial evaluating the neurological and functional effects of using an exoskeleton in individuals with chronic spinal cord injury. Design: A longitudinal, prospective, self-controlled feasibility study. Setting: Specialist Spinal Cord Injuries Centre, UK; 8 months during 2013–2014. Subjects: Individuals with chronic motor complete or incomplete spinal cord injury. Interventions: Enrolled subjects were assigned to 20 exoskeleton (ReWalk™, Argo Medical Technologies Ltd, Yokneam Ilit, Israel) training sessions over a 10-week training period. Main measures: Feasibility measures, clinical and mobility outcome measures and measures appraising subjects’ disability and attitude towards assistive technology were assessed before, during and after the study. Descriptive statistics were applied. Results: Out of 60 candidates, ten (17%) were enrolled and five (8%) completed the training programme. Primary reasons for not enrolling were ineligibility (n = 24, 40%) and limited interest to engage in a 10-week training programme (n = 16, 27%). Five out of ten enrolled subjects experienced grade I/II skin aberrations. While walking speeds were higher and walking distances were longer in all exoskeleton users when compared with non-use, the exoskeleton did generally not meet subjects’ high expectations in terms of perceived benefits. Conclusions: The conduct of a controlled trial evaluating the benefits of using exoskeletons that require a lengthy user-commitment to training of individuals with chronic motor complete or incomplete spinal cord injury comes with considerable feasibility challenges. Vigilance is required for preventing and detecting medical complications in spinal cord injury exoskeleton users.

The Effect of Using a Powered Exoskeleton Training Programme on Joint Range of Motion on Spinal Injured Individuals: A Pilot Study

Paralysis and loss of normal upright function is the most commonly acknowledged ongoing impairment related to spinal cord injury, although numerous co-morbidities exist. The risk and progress of some these conditions may be mitigated by upright function. Over-ground powered exoskeletons have the potential to provide many physical health benefits associated with upright mobility; however research into the specific effects of powered exoskeleton use on the joints does not yet exist. The ReWalkTM enables people with lower limb disabilities to carry out routine ambulatory functions such as walking, standing, sitting, and ascending/descending stairs. Changes in patients’ joint range of motion as a consequence of one week of intensive powered exoskeleton training as part of a physiotherapy programme were investigated.

An assistive controller for a lower-limb exoskeleton for rehabilitation after stroke, and preliminary assessment thereof.

This paper describes a novel controller, intended for use in a lower-limb exoskeleton, to aid gait rehabilitation in patients with hemiparesis after stroke. The controller makes use of gravity compensation, feedforward movement assistance, and reinforcement of isometric joint torques to achieve assistance without dictating the spatiotemporal nature of joint movement. The patient is allowed to self-select walking speed and is able to make trajectory adaptations to maintain balance without interference from the controller. The governing equations and the finite state machine which comprise the system are described herein. The control architecture was implemented in a lower-limb exoskeleton and a preliminary experimental assessment was conducted in which a patient with hemiparesis resulting from stroke walked with assistance from the exoskeleton. The patient exhibited improvements in fast gait speed, step length asymmetry, and stride length in each session, as measured before and after exoskeleton training, presumably as a result of using the exoskeleton.