Robotics for Lower Limb Rehabilitation

A Case Report of Becker Muscular Dystrophy and Stroke Who Successfully Regained Mobility With Robot-Assisted Gait Training

ABSTRACT

A 30-yr-old patient with Becker muscular dystrophy presented with stroke. Background issues of proximal weakness, dilated cardiomyopathy, and reduced endurance challenged the usual goal-setting and formulation of a stroke rehabilitation plan. We discuss the holistic rehabilitation program that this patient underwent, with a focus on the utilization of robot-assisted gait training that eventually led him to successfully regain mobility.

Efficacy of a Soft Robotic Exoskeleton to Improve Lower Limb Motor Function in Children with Spastic Cerebral Palsy: A Single-Blinded Randomized Controlled Trial

PURPOSE

Soft robotic exoskeletons (SREs) are portable, lightweight assistive technology with therapeutic potential for improving lower limb motor function in children with cerebral palsy. To understand the effects of long-term SRE-assisted walking training on children with spastic cerebral palsy (SCP), we designed a study aiming to elucidate the effects of SRE-assisted walking training on lower limb motor function in this population.

METHODS

In this randomized, single-blinded (outcome assessor) controlled trial, forty children diagnosed with SCP were randomized into the routine rehabilitation (RR) group (N = 20) and the SRE group (N = 20) for comparison. The RR group received routine rehabilitation training, and the SRE group received routine rehabilitation training combined with SRE-assisted overground walking training. Assessments (without SRE) were conducted pre- and post-intervention (8 weeks after the intervention). The primary outcome measures included the 10 m walk test (10MWT) and the 6 min walk test (6MWT). Secondary outcome measures comprised the gross motor function measure-88, pediatric balance scale modified Ashworth scale, and physiological cost index.

RESULTS

Both groups showed significant improvements (p < 0.01) across all outcome measures after the 8-week intervention. Between-group comparisons using ANCOVA revealed that the SRE group demonstrated greater improvement in walking speed from the 10MWT (+6.78 m/min, 95% CI [5.74-7.83]; p < 0.001) and walking distance during the 6MWT (+34.42 m, 95% CI [28.84-39.99]; p < 0.001). The SRE group showed greater improvement in all secondary outcome measures (p < 0.001).

CONCLUSIONS

The study findings suggested that the integration of SRE-assisted overground walking training with routine rehabilitation more effectively enhances lower limb motor function in children with SCP compared to routine rehabilitation alone.

Therapeutic robots for post-stroke rehabilitation

Stroke is a prevalent, severe, and disabling health-care issue on a global scale, inevitably leading to motor and cognitive deficits. It has become one of the most significant challenges in China, resulting in substantial social and economic burdens. In addition to the medication and surgical interventions during the acute phase, rehabilitation treatment plays a crucial role in stroke care. Robotic technology takes distinct advantages over traditional physical therapy, occupational therapy, and speech therapy, and is increasingly gaining popularity in post-stroke rehabilitation. The use of rehabilitation robots not only alleviates the workload of healthcare professionals but also enhances the prognosis for specific stroke patients. This review presents a concise overview of the application of therapeutic robots in post-stroke rehabilitation, with particular emphasis on the recovery of motor and cognitive function.

Human-Robot Joint Misalignment, Physical Interaction, and Gait Kinematic Assessment in Ankle-Foot Orthoses

Lower limb exoskeletons and orthoses have been increasingly used to assist the user during gait rehabilitation through torque transmission and motor stability. However, the physical human-robot interface (HRi) has not been properly addressed. Current orthoses lead to spurious forces at the HRi that cause adverse effects and high abandonment rates. This study aims to assess and compare, in a holistic approach, human-robot joint misalignment and gait kinematics in three fixation designs of ankle-foot orthoses (AFOs). These are AFOs with a frontal shin guard (F-AFO), lateral shin guard (L-AFO), and the ankle modulus of the H2 exoskeleton (H2-AFO). An experimental protocol was implemented to assess misalignment, fixation displacement, pressure interactions, user-perceived comfort, and gait kinematics during walking with the three AFOs. The F-AFO showed reduced vertical misalignment (peak of 1.37 ± 0.90 cm, p-value < 0.05), interactions (median pressures of 0.39-3.12 kPa), and higher user-perceived comfort (p-value < 0.05) when compared to H2-AFO (peak misalignment of 2.95 ± 0.64 and pressures ranging from 3.19 to 19.78 kPa). F-AFO also improves the L-AFO in pressure (median pressures ranging from 8.64 to 10.83 kPa) and comfort (p-value < 0.05). All AFOs significantly modified hip joint angle regarding control gait (p-value < 0.01), while the H2-AFO also affected knee joint angle (p-value < 0.01) and gait spatiotemporal parameters (p-value < 0.05). Overall, findings indicate that an AFO with a frontal shin guard and a sports shoe is effective at reducing misalignment and pressure at the HRI, increasing comfort with slight changes in gait kinematics.

Novel use of robot-assisted gait rehabilitation in a patient with stroke and blindness

Robot-assisted gait training (RAGT) is an effective adjunctive treatment for patients with stroke that helps to regain functional mobility and is applied in many rehabilitation units for poststroke neurorecovery. We discuss our successful attempt to apply RAGT in a patient with blindness that impeded his ability to maintain balance during gait training. He initially required two assistants to walk, but after undergoing conventional therapy with adjunctive RAGT, he improved to standby assistance for ambulation. There were also improvements in balance, activity tolerance and quality of life. Low-or-no vision states can affect the pace of recovery poststroke, but RAGT and conventional physiotherapy can possibly be combined in such patients to improve balance and motor outcomes. The Andago robot's safety features of weight support, harnessed suspension and walking mode selection supported our decision and enabled us to apply it safely for this patient.

An advanced bionic knee joint mechanism with neural network controller

In this article, a tensegrity-based knee mechanism is studied for developing a high-efficiency rehabilitation knee exoskeleton. Moreover, the kinematics and dynamics models of the knee mechanism are explored for bringing about further improvement in controller design. In addition, to estimate the performance of the bionic knee joint, based on the limit function of knee patella, the limit position functionality of the bionic knee joint is developed for enhancing the bionic property. Furthermore, to eliminate the noise item and other disturbances that are constantly generated in the rehabilitation process, a noise-tolerant zeroing neural network (NTZNN) algorithm is utilized to establish the controller. This indicates that the controller shows an anti-noise performance; hence, it is quite unique from other bionic knee mechanism controllers. Eventually, the anti-noise performance and the calculation of the precision of the NTZNN controller are verified through several simulation and contrast results.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Evaluation of the improvement of walking ability in patients with spinal cord injury using lower limb rehabilitation robots based on data science

Spinal cord injury (SCI) is a serious disabling injury, and the main factors causing SCI in patients include car accidents, falls from heights, as well as heavy blows and falls. These factors can all cause spinal cord compression or even complete rupture. After SCI, problems with the movement, balance, and walking ability of the lower limbs are most common, and SCI can cause abnormalities in patient's movement, sensation, and other aspects. Therefore, in the treatment of SCI, it is necessary to strengthen the rehabilitation training (RT) of patients based on data science to improve their motor ability and play a positive role in the recovery of their walking ability. This article used lower limb rehabilitation robot (LLRR) to improve the walking ability of SCI patients and applied them to SCI rehabilitation. The purpose is to improve the limb movement function of patients by imitating and assisting their limb movements, thereby achieving pain relief and muscle strength enhancement and promoting rehabilitation. The experimental results showed that the functional ambulation category (FAC) scale scores of Group A and Group B were 0.79 and 0.81, respectively, in the first 10 weeks of the experiment. After 10 weeks of the experiment, the FAC scores of Group A and Group B were 2.42 and 4.36, respectively. After the experiment, the FAC score of Group B was much higher than that of Group A, indicating that Group B was more effective in improving patients' walking ability compared to Group A. This also indicated that LLRR rehabilitation training can enhance the walking ability of SCI patients.

Evidence-based improvement of gait in post-stroke patients following robot-assisted training: A systematic review

BACKGROUND

The recovery of walking after stroke is a priority goal for recovering autonomy. In the last years robotic systems employed for Robotic Assisted Gait Training (RAGT) were developed. However, literature and clinical practice did not offer standardized RAGT protocol or pattern of evaluation scales.

OBJECTIVE

This systematic review aimed to summarize the available evidence on the use of RAGT in post-stroke, following the CICERONE Consensus indications.

METHODS

The literature search was conducted on PubMed, Cochrane Library and PEDro, including studies with the following criteria: 1) adult post-stroke survivors with gait disability in acute/subacute/chronic phase; 2) RAGT as intervention; 3) any comparators; 4) outcome regarding impairment, activity, and participation; 5) both primary studies and reviews.

RESULTS

Sixty-one articles were selected. Data about characteristics of patients, level of disability, robotic devices used, RAGT protocols, outcome measures, and level of evidence were extracted.

CONCLUSION

It is possible to identify robotic devices that are more suitable for specific phase disease and level of disability, but we identified significant variability in dose and protocols. RAGT as an add-on treatment seemed to be prevalent. Further studies are needed to investigate the outcomes achieved as a function of RAGT doses delivered.

Effects of robotic-assisted gait training on motor function and walking ability in children with thoracolumbar incomplete spinal cord injury

BACKGROUND: Spinal cord injury (SCI) results in neurological dysfunction of the spinal cord below the injury. OBJECTIVE: To explore the immediate and long-term effects of robotic-assisted gait training (RAGT) on the recovery of motor function and walking ability in children with thoracolumbar incomplete SCI. METHODS: Twenty-one children with thoracolumbar incomplete SCI were randomly divided into the experimental (n = 11) and control groups (n = 10). The control group received 60 min of conventional physical therapy, and the experimental group received 30 min of RAGT based on 30 minutes of conventional physical therapy. Changes in walking speed and distance, physiological cost index (PCI), lower extremity motor score (LEMS), SCI walking index and centre-of-pressure (COP) envelope area score were observed in both groups of children before and after eight weeks of training. The primary outcome measures were the 10-metre walk test (10MWT) and six-minute walk distance (6MWD) at preferred and maximal speeds. In addition, several other measures were assessed, such as postural control and balance, lower limb strength and energy expenditure. RESULTS: Compared with control group, the self-selected walk speed (SWS), maximum walking speed (MWS), 6MWD, PCI, LEMS, COP, and Walking Index for Spinal Cord injury II (WISCI II) of experimental group were improved after treatment. The 6MWD, PCI, COP, and WISCI II after eight weeks of treatment were improved in experimental group. All indicators were not identical at three different time points when compared between two groups. Pairwise comparisons in experimental group suggested that the SWS, MWS, 6MWD, PCI, LEMS, COP, and WISCI II after treatment were higher than those before treatment. The 6MWD, LEMS, COP, and WISCI II after treatment were higher than at the one-month follow-up appointment. The SWS, PCI, LEMS, COP, and WISCI II at the eight-week follow-up appointment were improved. CONCLUSION: Robotic-assisted gait training may significantly improve the immediate motor function and walking ability of children with thoracolumbar incomplete SCI.

Consensus Paper: Ataxic Gait

The aim of this consensus paper is to discuss the roles of the cerebellum in human gait, as well as its assessment and therapy. Cerebellar vermis is critical for postural control. The cerebellum ensures the mapping of sensory information into temporally relevant motor commands. Mental imagery of gait involves intrinsically connected fronto-parietal networks comprising the cerebellum. Muscular activities in cerebellar patients show impaired timing of discharges, affecting the patterning of the synergies subserving locomotion. Ataxia of stance/gait is amongst the first cerebellar deficits in cerebellar disorders such as degenerative ataxias and is a disabling symptom with a high risk of falls. Prolonged discharges and increased muscle coactivation may be related to compensatory mechanisms and enhanced body sway, respectively. Essential tremor is frequently associated with mild gait ataxia. There is growing evidence for an important role of the cerebellar cortex in the pathogenesis of essential tremor. In multiple sclerosis, balance and gait are affected due to cerebellar and spinal cord involvement, as a result of disseminated demyelination and neurodegeneration impairing proprioception. In orthostatic tremor, patients often show mild-to-moderate limb and gait ataxia. The tremor generator is likely located in the posterior fossa. Tandem gait is impaired in the early stages of cerebellar disorders and may be particularly useful in the evaluation of pre-ataxic stages of progressive ataxias. Impaired inter-joint coordination and enhanced variability of gait temporal and kinetic parameters can be grasped by wearable devices such as accelerometers. Kinect is a promising low cost technology to obtain reliable measurements and remote assessments of gait. Deep learning methods are being developed in order to help clinicians in the diagnosis and decision-making process. Locomotor adaptation is impaired in cerebellar patients. Coordinative training aims to improve the coordinative strategy and foot placements across strides, cerebellar patients benefiting from intense rehabilitation therapies. Robotic training is a promising approach to complement conventional rehabilitation and neuromodulation of the cerebellum. Wearable dynamic orthoses represent a potential aid to assist gait. The panel of experts agree that the understanding of the cerebellar contribution to gait control will lead to a better management of cerebellar ataxias in general and will likely contribute to use gait parameters as robust biomarkers of future clinical trials.

Minimal Contact Robotic Stroke Rehabilitation on Risk of COVID-19, Work Efficiency and Sensorimotor Function

Patients with hemiparetic stroke undergo direct, labor-intensive hands-on conventional physical therapy to improve sensorimotor function, spasticity, balance, trunk stability, and activities of daily living (ADLs). Currently, direct, intensive hands-on therapeutic modalities have increased concerns during the coronavirus (COVID-19) global pandemic. We developed an innovative Walkbot to mitigate the issues surrounding conventional hands-on physical therapy. We aimed to compare the effects of minimal-contact robotic rehabilitation (MRR) and full-contact conventional rehabilitation (FCR) on static and dynamic balance, trunk stability, ADLs, spasticity, and cognition changes in patients with hemiparetic stroke. A total of 64 patients with hemiparetic stroke (mean age = 66.38 ± 13.17; 27 women) underwent either MRR or FCR three times/week for 6 weeks. Clinical outcome measurements included the Trunk Impairment Scale (TIS), the Berg Balance Scale (BBS), the modified Ashworth Scale (MAS), the Fugl—Meyer Assessment (FMA), and the modified Barthel Index (MBI) scores. A 2 × 2 repeated analysis of variance (ANOVA) was performed, and an independent t-test was used to determine statistical differences in the physiotherapists’ work efficiency and COVID-19 transmission risk. The ANOVA showed that MRR had effects superior to those of FCR on the TIS, the BBS, the FMA, and the MBI (p < 0.05), but not on the MAS (p = 0.230). MRR showed a greater decrease on the physiotherapist’s work efficiency and COVID-19 transmission risk (p < 0.05). Our results provide clinical evidence that robot-assisted locomotor training helps maximize the recovery of sensorimotor function, abnormal synergy, balance, ADLs, and trunk stability, and facilitates a safer environment and less labor demand than conventional stroke rehabilitation.

Robotic Exoskeleton Gait Training in Stroke: An Electromyography-Based Evaluation

The recovery of symmetric and efficient walking is one of the key goals of a rehabilitation program in patients with stroke. The use of overground exoskeletons alongside conventional gait training might help foster rhythmic muscle activation in the gait cycle toward a more efficient gait. About twenty-nine patients with subacute stroke have been recruited and underwent either conventional gait training or experimental training, including overground gait training using a wearable powered exoskeleton alongside conventional therapy. Before and after the rehabilitation treatment, we assessed: (i) gait functionality by means of clinical scales combined to obtain a Capacity Score, and (ii) gait neuromuscular lower limbs pattern using superficial EMG signals. Both groups improved their ability to walk in terms of functional gait, as detected by the Capacity Score. However, only the group treated with the robotic exoskeleton regained a controlled rhythmic neuromuscular pattern in the proximal lower limb muscles, as observed by the muscular activation analysis. Coherence analysis suggested that the control group (CG) improvement was mediated mainly by spinal cord control, while experimental group improvements were mediated by cortical-driven control. In subacute stroke patients, we hypothesize that exoskeleton multijoint powered fine control overground gait training, alongside conventional care, may lead to a more fine-tuned and efficient gait pattern.

The Effects of Over-Ground Robot-Assisted Gait Training for Children with Ataxic Cerebral Palsy: A Case Report

Poor balance and ataxic gait are major impediments to independent living in ataxic cerebral palsy (CP). Robot assisted-gait training (RAGT) has been shown to improve the postural balance and gait function in children with CP. However, there is no report on the application of RAGT for children with ataxic CP. Here, we report two cases of children with ataxic CP who underwent over-ground RAGT along with conventional therapy for 4 weeks. Outcome measures including the gross motor function measure (GMFM), pediatric balance scale, pediatric reach scale, one-minute walk test, and Timed Up and Go test were assessed before and after the 4-week intervention. Both cases were well adapted to the RAGT system without any significant adverse event. Improvements in the GMFM after RAGT, compared with that in the GMFM, after intensive conventional therapy have been reported previously. It is noteworthy that over-ground RAGT improved areas of the GMFM that did not improve with conventional therapy. In addition, over-ground RAGT with conventional therapy led to improvements in functional balance and walking capacity. These findings suggest that over-ground RAGT is feasible and may be a potential option for enhancing balance and functional walking capacity in children with ataxic CP.

Cardiac Rehabilitation Early after Sternotomy Using New Assistive VR-Enhanced Robotic Exoskeleton-Study Protocol for a Randomised Controlled Trial

(1) Background and objective: Cardiac rehabilitation (CR) means delivering health education by structured exercises with the means of risk reduction, in a cost-effective manner. Well-conducted CR improves functional capacity, decreases re-hospitalization, and reduces mortality up to 25%. We bring to attention the protocol of a randomised control trial with the aim of validating the prototype of an assistive upper-body robotic exoskeleton system enhanced with a non-immersive virtual reality exergame (CardioVR-ReTone) in patients who undergone cardiac surgery. (2) Methods: Description of the CardioVR-ReTone system and the technical specification, followed by the group selection, randomization and evaluated variables. (3) Expected results: The primary outcome measurement is the modification of life quality at the end of the CR exercise training program. Secondary outcomes will encompass measurements of sternal stability, muscular activity, cardiac response to exercise, pain level and compliance/adherence to CR. (4) Conclusions: Implementing these novel features of the CardioVR-ReTone system, addressability, and efficacy of CR, so problematic in certain situations and especially in cardiac surgery, will be greatly facilitated, being independent of the skills and availability of the rehabilitation therapist.

Effectiveness of Adjunct Robotic Therapy With a Patient-Guided Suspension System for Stroke Rehabilitation Using a 7-Days-a-Week Model of Care: A Comparison With Conventional Rehabilitation

Objective

To determine and compare the effectiveness of robotic therapy with a patient-guided suspension system for stroke rehabilitation using a 7-days-a-week model of care with that of conventional rehabilitation.

Design

Retrospective cohort study.

Setting

Inpatient rehabilitation unit of an acute general hospital.

Participants

A total of 100 consecutive patients with stroke (N=100) admitted within a 7-month period who fulfilled the criteria to undergo robotic therapy with a patient-guided suspension system were enrolled in this study.

Interventions

Patients either underwent robotic therapy in addition to conventional therapy (robotic group) or conventional therapy only (control group). There were 50 patients in each cohort.

Main Outcome Measures

FIM and its derivatives (FIM gain and FIM efficiency); Berg Balance Scale (BBS), functional ambulation category (FAC); modified Rankin Scale (mRS); and National Institutes of Health Stroke Scale.

Results

The average FIM gains in both groups were statistically significant (P<.01). The robotic group had greater improvement in FAC scores (1.24 vs 0.78, P=.007). However, other measurements such as FIM efficiency, BBS, and mRS were not significantly different between the 2 groups. The robotics group reported high patient satisfaction rates, with most patients finding the intervention both beneficial and desirable.

Conclusions

Adjunct robotic therapy has the potential to increase the efficacy of stroke rehabilitation. However, further studies are needed to strengthen the evidence.

Lower-Limb Exosuits for Rehabilitation or Assistance of Human Movement: A Systematic Review

Background: The aim of this review is to provide a comprehensive overview of the technological state-of-the-art of exosuits and the clinical results obtained when applied to users with mobility impairment. Methods: Searches are carried out in the COCHRANE, PubMed, IEEE Xplore and MEDLINE databases. Titles, abstracts and full texts are screened for inclusion criteria. Technological and clinical data are extracted. The quality of the studies is evaluated via a study quality assessment tool. Results: 19 studies are identified as relevant. Active (47%) and passive exosuits (53%) are used. Most are used untethered (84%), accommodating the demand of mobility. No study reports power consumption, which is important for dimensioning power systems. Fields of applications are post-stroke (79%), osteoarthritis (16%) and post-trauma (5%). Mostly the ankle joint is addressed (57%), while less studies address multiple joints (21%). The outcomes of clinical evaluations of lower-limb exosuits with patients suffering from mobility impairments are positive in the correction of gait pattern and reducing metabolic energy consumption during hemiparetic walking. Conclusions: Lower-limb exosuits for clinical applications are still facing technological challenges. Fields of application are limited to stroke, osteoarthritis and trauma. While clinical outcomes are overall positive, improvements in the study protocols are suggested.

Hybrid Assistive Limb Functional Treatment for a Patient with Chronic Incomplete Cervical Spinal Cord Injury

Introduction

The hybrid assistive limb (HAL) is a wearable exoskeleton cyborg that assists walking and lower limb movements via real-time actuator control by detecting the wearer’s bioelectric signals on the surface of their skin.

Purpose

The purpose of this study was to report the improvement in walking ability following HAL gait training in a patient with tetraplegia after incomplete cervical spinal cord injury (SCI).

Patient and Methods

A 47-year-old man with traumatic cervical SCI for six months after fall had incomplete tetraplegic SCI grade C as classified according to the American Spinal Cord Injury Association impairment scale and was unable to walk in conventional rehabilitation.

Results

The HAL gait training was received 2 or 3 times per week for 13 sessions. Improvement was observed in gait speed (baseline: 0.12; after training: 0.45 m/sec), step length (baseline: 0.30; after training: 0.45 m), and cadence (baseline: 23.1; after training: 59.6 steps/min) based on a 10-meter walking test; International Standards for Neurological and functional Classification of Spinal Cord Injury (ISNCSCI) motor score (baseline: 59; after training: 76); and walking index for spinal cord injury (WISCI) II score (baseline: 1; after training: 6).

Conclusion

We report the recovery of walking ability in a patient with chronic severe incomplete tetraplegic SCI following the HAL training.

Development of nonmotorized mechanisms for lower limb rehabilitation

This paper concerns with the development of three nonmotorized individual lower limb joints rehabilitation mechanisms based on a four-bar linkage, and mechanical movement transmission from the motion of the patient’s upper limb. Initially, mathematical and computational models are built based on the desired angular motions for the hip, knee, and ankle. A prototype for the knee mechanism was constructed for initial experimental tests. The first test with wooden mannequin show that this prototype is lightweight, has an output movement compatible with the amplitudes, is easy to build and operate, being thus ready for clinical tests with healthy and impaired subjects.

Overground Robot-Assisted Gait Training for Pediatric Cerebral Palsy

The untethered exoskeletal robot provides patients with the freest and realistic walking experience by assisting them based on their intended movement. However, few previous studies have reported the effect of robot-assisted gait training (RAGT) using wearable exoskeleton in children with cerebral palsy (CP). This pilot study evaluated the effect of overground RAGT using an untethered torque-assisted exoskeletal wearable robot for children with CP. Three children with bilateral spastic CP were recruited. The robot generates assistive torques according to gait phases automatically detected by force sensors: flexion torque during the swing phase and extension torque during the stance phase at hip and knee joints. The overground RAGT was conducted for 17~20 sessions (60 min per session) in each child. The evaluation was performed without wearing a robot before and after the training to measure (1) the motor functions using the gross motor function measure and the pediatric balance scale and (2) the gait performance using instrumented gait analysis, the 6-min walk test, and oxygen consumption measurement. All three participants showed improvement in gross motor function measure after training. Spatiotemporal parameters of gait analysis improved in participant P1 (9-year-old girl, GMFCS II) and participant P2 (13-year-old boy, GMFCS III). In addition, they walked faster and farther with lower oxygen consumption during the 6-min walk test after the training. Although participant P3 (16-year-old girl, GMFCS IV) needed the continuous help of a therapist for stepping at baseline, she was able to walk with the platform walker independently after the training. Overground RAGT using a torque-assisted exoskeletal wearable robot seems to be promising for improving gross motor function, walking speed, gait endurance, and gait efficiency in children with CP. In addition, it was safe and feasible even for children with severe motor impairment (GMFCS IV).

Systematic review on wearable lower-limb exoskeletons for gait training in neuromuscular impairments

Gait disorders can reduce the quality of life for people with neuromuscular impairments. Therefore, walking recovery is one of the main priorities for counteracting sedentary lifestyle, reducing secondary health conditions and restoring legged mobility. At present, wearable powered lower-limb exoskeletons are emerging as a revolutionary technology for robotic gait rehabilitation. This systematic review provides a comprehensive overview on wearable lower-limb exoskeletons for people with neuromuscular impairments, addressing the following three questions: (1) what is the current technological status of wearable lower-limb exoskeletons for gait rehabilitation?, (2) what is the methodology used in the clinical validations of wearable lower-limb exoskeletons?, and (3) what are the benefits and current evidence on clinical efficacy of wearable lower-limb exoskeletons? We analyzed 87 clinical studies focusing on both device technology (e.g., actuators, sensors, structure) and clinical aspects (e.g., training protocol, outcome measures, patient impairments), and make available the database with all the compiled information. The results of the literature survey reveal that wearable exoskeletons have potential for a number of applications including early rehabilitation, promoting physical exercise, and carrying out daily living activities both at home and the community. Likewise, wearable exoskeletons may improve mobility and independence in non-ambulatory people, and may reduce secondary health conditions related to sedentariness, with all the advantages that this entails. However, the use of this technology is still limited by heavy and bulky devices, which require supervision and the use of walking aids. In addition, evidence supporting their benefits is still limited to short-intervention trials with few participants and diversity among their clinical protocols. Wearable lower-limb exoskeletons for gait rehabilitation are still in their early stages of development and randomized control trials are needed to demonstrate their clinical efficacy.

Lower limb rehabilitation robotics: The current understanding and technology

BACKGROUND

With the increasing rate of ambulatory disabilities and rise in the elderly population, advance methods to deliver the rehabilitation and assistive services to patients have become important. Lower limb robotic therapeutic and assistive aids have been found to improve the rehabilitation outcome.

OBJECTIVE

The article aims to present the updated understanding in the field of lower limb rehabilitation robotics and identify future research avenues.

METHODS

Groups of keywords relating to assistive technology, rehabilitation robotics, and lower limb were combined and searched in EMBASE, IEEE Xplore Digital Library, Scopus, Web of Science and Google Scholar database.

RESULTS

Based on the literature collected from the databases we provide an overview of the understanding of robotics in rehabilitation and state of the art devices for lower limb rehabilitation. Technological advancements in rehabilitation robotic architecture (sensing, actuation and control) and biomechanical considerations in design have been discussed. Finally, a discussion on the major advances, research directions, and challenges is presented.

CONCLUSIONS

Although the use of robotics has shown a promising approach to rehabilitation and reducing the burden on caregivers, extensive and innovative research is still required in both cognitive and physical human-robot interaction to achieve treatment efficacy and efficiency.

Brain Functional Connectivity in Unconstrained Walking With and Without an Exoskeleton

An exoskeleton is utilized to effectively restore the motor function of amputees' limbs and is frequently employed in motor rehabilitation training during convalescence. Understanding of exoskeleton impact on the brain is required in order to better and more efficiently use the exoskeleton. Almost all previous studies investigated the exoskeleton effect on the brain in a situation with constraints such as predefined walking speed, which could lead to findings differed from that obtained in an unconstrained situation. We, therefore, performed an experiment of unconstrained walking with and without an exoskeleton. Both individual connections and graph metrics were explored and compared among walking conditions. We found that low-order functional connections and associated high-order functional connections mainly between the left centroparietal region and right frontal region were significantly different among walking conditions. Generally speaking, connective strength was enhanced in LOFC and was decreased in aHOFC when assistant force was provided by the exoskeleton. Further, we proposed connection length investigation and revealed the large majority of these connections were long-distance connectivity. Graph metric investigation discovered higher connectivity clustering in the walking with low exoskeleton-aided force compared to the walking without the exoskeleton. This study expanded the existing knowledge of the effect of exoskeleton on the brain and is of implications on new exoskeleton development and exoskeleton-aided rehabilitation training.