Therapeutic Robotics: A Technology Push: Stroke rehabilitation is being aided by robots that guide movement of shoulders and elbows, wrists, hands, arms and ankles to significantly improve recovery of patients

Design recommendations for exoskeletons: Perspectives of individuals with spinal cord injury

OBJECTIVE

This study investigated the expectations of individuals with spinal cord injury (SCI) regarding exoskeletons.

DESIGN

The survey consisted out of questions regarding multiple aspects of exoskeleton technology.

SETTING

An online survey was distributed via the monthly newsletter of the Dutch Patient Association for Spinal Cord Injury (SCI).

PARTICIPANTS

Individuals with SCI who are members of the Dutch Patient Association for SCI.

OUTCOME MEASURES

General impression of exoskeleton technology, expectations regarding capabilities and user-friendliness, training expectations and experiences, future perspectives and points of improvement.

RESULTS

The survey was filled out by 95 individuals with SCI, exoskeletons were considered positive and desirable by 74.7%. About 11 percent (10.5%) thought one could ambulate faster, or just as fast, while wearing an exoskeleton as able-bodied people. Furthermore, 18.9% expected not to use a wheelchair or walking aids while ambulating with the exoskeleton. Twenty-five percent believed that exoskeletons could replace wheelchairs. Some main points of improvement included being able to wear the exoskeleton in a wheelchair and while driving a car, not needing crutches while ambulating, and being able to put the exoskeleton on by oneself.

CONCLUSION

Individuals with SCI considered exoskeletons as a positive and desirable innovation. But based on the findings from the surveys, major points of improvement are necessary for exoskeletons to replace wheelchairs in the future. For future exoskeleton development, we recommend involvement of individuals with SCI to meet user expectations and improve in functionality, usability and quality of exoskeletons.

Robot-assisted therapy for upper limb paresis after stroke: Use of robotic algorithms in advanced practice

BACKGROUND

Rehabilitation of stroke-related upper limb paresis is a major public health issue.

OBJECTIVE

Robotic systems have been developed to facilitate neurorehabilitation by providing key elements required to stimulate brain plasticity and motor recovery, namely repetitive, intensive, adaptative training with feedback. Although the positive effect of robot-assisted therapy on motor impairments has been well demonstrated, the effect on functional capacity is less certain.

METHOD

This narrative review outlines the principles of robot-assisted therapy for the rehabilitation of post-stroke upper limb paresis.

RESULTS

A paradigm is proposed to promote not only recovery of impairment but also function.

CONCLUSION

Further studies that would integrate some principles of the paradigm described in this paper are needed.

The effects of robot-assisted gait training combined with non-invasive brain stimulation on lower limb function in patients with stroke and spinal cord injury: A systematic review and meta-analysis

Objective:

This study aimed to investigate the effect of robot-assisted gait training (RAGT) therapy combined with non-invasive brain stimulation (NIBS) on lower limb function in patients with stroke and spinal cord injury (SCI).

Data sources

PubMed, Cochrane Central Register of Controlled Trials, Ovid MEDLINE, and Web of Science were searched.

Study selection

Randomized controlled trials (RCTs) published as of 3 March 2021. RCTs evaluating RAGT combined with NIBS, such as transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS), for lower limb function (e.g., Fugl-Meyer assessment for patients with stroke) and activities (i.e., gait velocity) in patients with stroke and SCI were included.

Data extraction

Two reviewers independently screened the records, extracted the data, and assessed the risk of bias.

Data synthesis

A meta-analysis of five studies (104 participants) and risk of bias were conducted. Pooled estimates demonstrated that RAGT combined with NIBS significantly improved lower limb function [standardized mean difference (SMD) = 0.52; 95% confidence interval (CI) = 0.06–0.99] but not lower limb activities (SMD = −0.13; 95% CI = −0.63–0.38). Subgroup analyses also failed to find a greater improvement in lower limb function of RAGT with tDCS compared to sham stimulation. No significant differences between participant characteristics or types of NIBS were observed.

Conclusion

This meta-analysis demonstrated that RAGT therapy in combination with NIBS was effective in patients with stroke and SCI. However, a greater improvement in lower limb function and activities were not observed using RAGT with tDCS compared to sham stimulation.

The Impact of Cognition on Motor Learning and Skill Acquisition Using a Robot Intervention in Infants With Cerebral Palsy

Background: Cerebral Palsy (CP) is a neurodevelopmental disorder that encompasses multiple neurological disorders that appear in infancy or early childhood and persist through the lifespan of the individual. Early interventions for infants with CP utilizing assisted-motion robotic devices have shown promising effects in rehabilitation of the motor function skills. The impact of cognitive function during motor learning and skill acquisition in infants using robotic technologies is unclear.

Purpose: To assess the impact of cognitive function of infants with and without CP on their motor learning using the Self-Initiated Prone Progression Crawler (SIPPC) robot.

Methods: Statistical analysis was conducted on the data obtained from a randomized control trial in which the movement learning strategies in infants with or at risk for CP was assessed during a 16-week SIPPC robot intervention. Cognitive function was measured by the Bayley scales of Infant and Toddler Development–Third edition (Bayley-III) and motor function was measured by the Movement Observation Coding Scheme (MOCS). The infants were categorized into three distinct groups based on their cognitive scores at baseline: “above average” (n₁ = 11), “below average” (n₂ = 10), and “average” (n₃ = 26). Tri-weekly averages of the MOCS scores (observations at five time points) were used for the analyses. This study involved computing descriptive statistics, data visualization, repeated measures analysis of variances (rmANOVA), and survival analyses.

Results: The descriptive statistics were calculated for the MOCS and Bayley III scores. The repeated measures ANOVAs revealed that there was a statistically significant effect of time (p < 0.0001) on scores of all subscales of the MOCS. A statistically significant effect of interaction between group and time (p < 0.05) was found in MOCS scores of subscales 1 and 2. The survival analyses indicated that infants in different cognition groups significantly differed (p < 0.0001) in their ability to achieve the crawling milestone within the 16-week intervention period.

Conclusion: The findings in this study reveal the key movement strategies required to move the SIPPC robot, assessed by the MOCS, vary depending on the infants’ cognition. The SIPPC robot is well-matched to cognitive ability of infants with CP. However, lower cognitive ability was related to delayed improvement in their motor skills.

Robot-Assisted Therapy and Constraint-Induced Movement Therapy for Motor Recovery in Stroke: Results From a Randomized Clinical Trial

Background: Stroke is one of the leading causes of adult disability, and up to 80% of stroke survivors undergo upper extremity motor dysfunction. Constraint-Induced Movement Therapy (CIMT) and Robot-Assisted Therapy (RT) are used for upper limb stroke rehabilitation. Although CIMT and RT are different techniques, both are beneficial; however, their results must be compared. The objective is to establish the difference between RT and CIMT after a rehabilitation program for chronic stroke patients.

Method: This is a randomized clinical trial, registered at ClinicalTrials.gov (ID number NCT02700061), in which patients with stroke received sessions of RT or CIMT protocol, combined with a conventional rehabilitation program for 12 weeks. The primary outcome was measured by Wolf Motor Function Test (WMFT) and Fugl-Meyer Assessment—Upper Limb (FMA-UL). Activities of daily living were also assessed.

Results: Fifty one patients with mild to moderate upper limb impairment were enrolled in this trial, 25 women and 26 men, mean age of 60,02 years old (SD 14,48), with 6 to 36 months after stroke onset. Function significantly improved regardless of the treatment group. However, no statistical difference was found between both groups as p-values of the median change of function measured by WMFT and FMA were 0.293 and 0.187, respectively.

Conclusion: This study showed that Robotic Therapy (RT) was not different from Constraint-Induced Movement Therapy (CIMT) regardless of the analyzed variables. There was an overall upper limb function, motor recovery, functionality, and activities of daily living improvement regardless of the interventions. At last, the combination of both techniques should be considered in future studies.

Review: How Can Intelligent Robots and Smart Mechatronic Modules Facilitate Remote Assessment, Assistance, and Rehabilitation for Isolated Adults With Neuro-Musculoskeletal Conditions?

Worldwide, at the time this article was written, there are over 127 million cases of patients with a confirmed link to COVID-19 and about 2.78 million deaths reported. With limited access to vaccine or strong antiviral treatment for the novel coronavirus, actions in terms of prevention and containment of the virus transmission rely mostly on social distancing among susceptible and high-risk populations. Aside from the direct challenges posed by the novel coronavirus pandemic, there are serious and growing secondary consequences caused by the physical distancing and isolation guidelines, among vulnerable populations. Moreover, the healthcare system's resources and capacity have been focused on addressing the COVID-19 pandemic, causing less urgent care, such as physical neurorehabilitation and assessment, to be paused, canceled, or delayed. Overall, this has left elderly adults, in particular those with neuromusculoskeletal (NMSK) conditions, without the required service support. However, in many cases, such as stroke, the available time window of recovery through rehabilitation is limited since neural plasticity decays quickly with time. Given that future waves of the outbreak are expected in the coming months worldwide, it is important to discuss the possibility of using available technologies to address this issue, as societies have a duty to protect the most vulnerable populations. In this perspective review article, we argue that intelligent robotics and wearable technologies can help with remote delivery of assessment, assistance, and rehabilitation services while physical distancing and isolation measures are in place to curtail the spread of the virus. By supporting patients and medical professionals during this pandemic, robots, and smart digital mechatronic systems can reduce the non-COVID-19 burden on healthcare systems. Digital health and cloud telehealth solutions that can complement remote delivery of assessment and physical rehabilitation services will be the subject of discussion in this article due to their potential in enabling more effective and safer NMSDK rehabilitation, assistance, and assessment service delivery. This article will hopefully lead to an interdisciplinary dialogue between the medical and engineering sectors, stake holders, and policy makers for a better delivery of care for those with NMSK conditions during a global health crisis including future pandemics.

Coordinative Motion-Based Bilateral Rehabilitation Training System with Exoskeleton and Haptic Devices for Biomedical Application

According to the neuro-rehabilitation theory, compared with unilateral training, bilateral training is proven to be an effective method for hemiparesis, which affects the most part of stroke patients. In this study, a novel bilateral rehabilitation training system, which incorporates a lightweight exoskeleton device worn on the affected limb; a haptic device (Phantom Premium), which is used for generating a desired tactile feedback for the affected limb; and a VR (virtual reality) graphic interface, has been developed. The use of VR technology during rehabilitation can provide goal directed tasks with rewards and motivate the patient to undertake extended rehabilitation. This paper is mainly focused on elbow joint training, and other independent joints can be trained by easily changing the VR training interface. The haptic device is adopted to enable patients to use their own decision making abilities with a tactical feedback. Integrated with a VR-based graphic interface, the goal-oriented task can help to gradually recovery their motor function with a coordinative motion between two limbs. In particular, the proposed system can accelerate neural plasticity and motor recovery in those patients with little muscle strength by using the exoskeleton device. The exoskeleton device can provide from relatively high joint impedance to near-zero impedance, and can provide a partial assist as the patient requires.

SMART Arm Training With Outcome-Triggered Electrical Stimulation in Subacute Stroke Survivors With Severe Arm Disability: A Randomized Controlled Trial

Background. Stroke survivors with severe upper limb disability need opportunities to engage in task-oriented practice to achieve meaningful recovery. Objective. To compare the effect of SMART Arm training, with or without outcome-triggered electrical stimulation to usual therapy, on arm function for stroke survivors with severe upper limb disability undergoing inpatient rehabilitation. Methods. A prospective, multicenter, randomized controlled trial was conducted with 3 parallel groups, concealed allocation, assessor blinding and intention-to-treat analysis. Fifty inpatients within 4 months of stroke with severe upper limb disability were randomly allocated to 60 min/d, 5 days a week for 4 weeks of (1) SMART Arm with outcome-triggered electrical stimulation and usual therapy, (2) SMART Arm alone and usual therapy, or (3) usual therapy. Assessment occurred at baseline (0 weeks), posttraining (4 weeks), and follow-up (26 and 52 weeks). The primary outcome measure was Motor Assessment Scale item 6 (MAS6) at posttraining. Results. All groups demonstrated a statistically ( P < .001) and clinically significant improvement in arm function at posttraining (MAS6 change ≥1 point) and at 52 weeks (MAS6 change ≥2 points). There were no differences in improvement in arm function between groups (P = .367). There were greater odds of a higher MAS6 score in SMART Arm groups as compared with usual therapy alone posttraining (SMART Arm stimulation generalized odds ratio [GenOR] = 1.47, 95%CI = 1.23-1.71) and at 26 weeks (SMART Arm alone GenOR = 1.31, 95% CI = 1.05-1.57). Conclusion. SMART Arm training supported a clinically significant improvement in arm function, which was similar to usual therapy. All groups maintained gains at 12 months.

An upper-body rehabilitation exoskeleton Harmony with an anatomical shoulder mechanism: Design, modeling, control, and performance evaluation

We present an upper-body exoskeleton for rehabilitation, called Harmony, that provides natural coordinated motions on the shoulder with a wide range of motion, and force and impedance controllability. The exoskeleton consists of an anatomical shoulder mechanism with five active degrees of freedom, and one degree of freedom elbow and wrist mechanisms powered by series elastic actuators. The dynamic model of the exoskeleton is formulated using a recursive Newton–Euler algorithm with spatial dynamics representation. A baseline control algorithm is developed to achieve dynamic transparency and scapulohumeral rhythm assistance, and the coupled stability of the robot–human system at the baseline control is investigated. Experiments were conducted to evaluate the kinematic and dynamic characteristics of the exoskeleton. The results show that the exoskeleton exhibits good kinematic compatibility to the human body with a wide range of motion and performs task-space force and impedance control behaviors reliably.

The Present and Future of Robotic Technology in Rehabilitation

Robotic technology designed to assist rehabilitation can potentially increase the efficiency of and accessibility to therapy by assisting therapists to provide consistent training for extended periods of time, and collecting data to assess progress. Automatization of therapy may enable many patients to be treated simultaneously and possibly even remotely, in the comfort of their own homes, through telerehabilitation. The data collected can be used to objectively assess performance and document compliance as well as progress. All of these characteristics can make therapists more efficient in treating larger numbers of patients. Most importantly for the patient, it can increase access to therapy which is often in high demand and rationed severely in today's fiscal climate. In recent years, many consumer grade low-cost and off-the-shelf devices have been adopted for use in therapy sessions and methods for increasing motivation and engagement have been integrated with them. This review paper outlines the effort devoted to the development and integration of robotic technology for rehabilitation.

A NOVEL MULTI-DOF EXOSKELETON ROBOT FOR UPPER LIMB REHABILITATION

Patients who suffer from stroke have motion function disorders. They need rehabilitation training guided by doctors and trainers. Nowadays, robots have been introduced to help the patients regain their motion function in rehabilitation training. In this paper, a novel multi degree of freedom (DOF) exoskeleton robot, with light weight, including (6[Formula: see text]1) DOFs, named as Rehab-Arm, is proposed and developed for upper limb rehabilitation. The joints of the robot are equipped with micro motors which are capable of actuating each DOF respectively and simultaneously. The medial/lateral rotation of shoulder is realized by a semi-circle guide mechanism for convenience consideration and safety. The robot is used in sitting posture which is attached to a custom made chair. Hence, the robot can be used to assist patients in passive movement with 7 DOFs of the upper limb for rehabilitation. Five adult healthy male subjects participated in the experiment to test the joint movement accuracy of the robot. Finally, subjects can wear Rehab-Arm and move their upper limb, led by micro motors of the robot, to perform task assigned with specific trajectory.

Development of Six-DOF Human Ankle Motion Control Device Using Stewart Platform Structure for Fall Prevention

[abstFig src='/00280005/06.jpg' width='300' text='Developed device' ] According to a worldwide WHO survey, about one-third of people at the age of 65 or older experience at least one fall a year, which may result in a severe injury. Meanwhile, the population of the developed world is increasingly aging, and fall incidents can be therefore considered as a global problem. The causes of falls include the weakening of the tibialis anterior and gastrocnemius muscles that respectively play important roles in the dorsal and plantar flexion of the foot, and deterioration of the functions necessary to recover balance from perturbations during gait. Such dysfunctions are treated with rehabilitation provided by physical therapists and with special gait training in which the patient is subjected to perturbations. Although devices for rehabilitation and gait training have been developed, they are problematic since they only allow the ankle joint to move at a low number of degrees of freedom (DOF). In this study, we developed an ankle foot orthosis to provide six-DOF control of the ankle joint using a parallel link mechanism known as a Stewart platform. The Stewart platform construction makes it possible to provide six-DOF control. Since the ankle foot orthosis can be applied to walking, it can assist walking or gait training. In one of our prior studies, we proposed a force control method for the device, and verified its accuracy. In the present study, we improved the attachment method and introduced a pressure sensor to the previous version of the device to allow implementation of a new method that enables control adapted to the human gait. In addition, we conducted four experiments to verify whether it is possible to reproduce the physical therapist’s rehabilitation manipulations without limiting the ankle joint’s DOF, provide arbitrary walking assist action, and impart perturbations to the subject during gait. The first experiment verified the device’s accuracy in reproducing motion, the second confirmed the dispersion of the reproduced motion, the third assessed the walking-assist performance to prevent trips, and the fourth ascertained whether it is possible to make the subject lose balance by the imparted perturbation. The results demonstrated that the motions can be reproduced with high accuracy and with low dispersion and that the ankle joint motions can be controlled adaptively to fit the subject’s gait, suggesting the usefulness of the proposed device.

CONTROL OF FOREARM MODULE IN UPPER-LIMB REHABILITATION ROBOT FOR REDUCTION AND BIOMECHANICAL ASSESSMENT OF PRONATOR HYPERTONIA OF STROKE PATIENTS

Spastic hypertonia causes loss of range of motion (ROM) and contractures in patients with post-stroke hemiparesis. The pronation/supination of the forearm is an essential functional movement in daily activities. We developed a special module for a shoulder-elbow rehabilitation robot for the reduction and biomechanical assessment of pronator/supinator hypertonia of the forearm. The module consisted of a rotational drum driven by an AC servo motor and equipped with an encoder and a custom-made torque sensor. By properly switching the control algorithm between position control and torque control, a hybrid controller able to mimic a therapist’s manual stretching movements was designed. Nine stroke patients were recruited to validate the functions of the module. The results showed that the affected forearms had significant increases in the ROM after five cycles of stretching. Both the passive ROM and the average stiffness were highly correlated to the spasticity of the forearm flexor muscles as measured using the Modified Ashworth Scale (MAS). With the custom-made module and controller, this upper-limb rehabilitation robot may be able to aid physical therapists to reduce hypertonia and quantify biomechanical properties of the muscles for forearm rotation in stroke patients.

Development of Stewart platform type ankle-foot device for trip prevention support

This paper presents an ankle-foot device using a Stewart platform, which is a type of parallel-link mechanism, for trip prevention support. The developed device can reproduce the input motions of the ankle joint in six degrees of freedom by controlling six pneumatic cylinders at the same time. The root mean square errors of the 3-D position and rotation angle of the reproduced motions with the input motions (dorsiflexion and plantar flexion) were 6.3 mm and 3.0°, respectively. Verification experiments for trip prevention support performance were conducted by comparing motions in each walking condition measured using a motion capture system. The experimental results showed that the minimum foot clearance during mid-swing and initial swing increased significantly by the trip prevention support offered by the developed device. The developed device can perform passive exercises for ankle rehabilitation and support walking for trip prevention.

Monitoring System for Elderly People Using Passive RFID Tags

<div class=""abs_img""><img src=""[disp_template_path]/JRM/abst-image/00260005/14.jpg"" width=""200"" />

Monitoring system using RFID tags</div> This paper presents amonitoring systemthat uses passive RFID tags for detection of unexpected loitering and falling of elderly people in nursing homes. This system, which is superior to a video camera in terms of privacy, incorporates tag readers set on ceilings beside a bed and under doors. The system combines the following two methods. The first method targets caregivers and non-senile elderly persons. Each wears an RFID shoulder tag. However, some senile elderly people who are not wearing RFID tags might wander. Therefore, the second method described for this system is based on a phenomenon by which electric waves are attenuated by water. Several RFID tags are put on the floor. Then the presence of a person at that spot is inferred from the number of RFID tags that are responding. Experimental results obtained for a person beside a bed and passing through a door confirm the effectiveness of this system. </span>

PNEUMATIC PLANAR REHABILITATION ROBOT FOR POST-STROKE PATIENTS

Cerebrovascular accident or stroke in aging population is the primary cause of disability and the second leading cause of death in many countries, including Spain. Arm impairment is common and the recovery is partly dependent on the intensity and frequency of rehabilitation intervention. However, physical therapy resources are often limited, so methods of supplementing traditional physiotherapy, such as robot assisted therapy, are essential. This paper describes design, development and control aspects of a planar robot driven by pneumatic swivel modules for upper-limb rehabilitation of post-stroke patients. Moreover, first experimental results with one post-stroke patient are presented to show the benefits of using the proposed system.

On the role of auditory feedback in robot-assisted movement training after stroke: review of the literature

The goal of this paper is to address a topic that is rarely investigated in the literature of technology-assisted motor rehabilitation, that is, the integration of auditory feedback in the rehabilitation device. After a brief introduction on rehabilitation robotics, the main concepts of auditory feedback are presented, together with relevant approaches, techniques, and technologies available in this domain. Current uses of auditory feedback in the context of technology-assisted rehabilitation are then reviewed. In particular, a comparative quantitative analysis over a large corpus of the recent literature suggests that the potential of auditory feedback in rehabilitation systems is currently and largely underexploited. Finally, several scenarios are proposed in which the use of auditory feedback may contribute to overcome some of the main limitations of current rehabilitation systems, in terms of user engagement, development of acute-phase and home rehabilitation devices, learning of more complex motor tasks, and improving activities of daily living.

Cartesian stiffness for wrist joints: analysis on the Lie group of 3D rotations and geometric approximation for experimental evaluation

This paper is concerned with the analysis and the numerical evaluation from experimental measurements of the static, Cartesian stiffness of wrist joints, in particular the human wrist. The primary aim is to extend from Euclidean spaces to so(3), the group of rigid body rotations, previous methods for assessing the end-point stiffness of the human arm, typically performed via a robotic manipulandum. As a first step, the geometric definition of Cartesian stiffness from current literature is specialised to the group so(3). Emphasis is placed on the choice of the unique, natural, affine connection on so(3) which guarantees symmetry of the stiffness matrix in presence of conservative fields for any configuration, also out of equilibrium. As the main contribution of this study, a coordinate-independent approximation based on the geometric notion of geodesics is proposed which provides a working equation for evaluating stiffness directly from experimental measurements. Finally, a graphical representation of the stiffness is discussed which extends the ellipse method often used for end-point stiffness visualisation and which is suitable to compare stiffness matrices evaluated at different configurations.

A large clinical study on the ability of stroke patients to use an EEG-based motor imagery brain-computer interface

Brain-computer interface (BCI) technology has the prospects of helping stroke survivors by enabling the interaction with their environ ment through brain signals rather than through muscles, and restoring motor function by inducing activity-dependent brain plasticity. This paper presents a clinical study on the extent of detectable brain signals from a large population of stroke patients in using EEG-based motor imagery BCI. EEG data were collected from 54 stroke patients whereby finger tapping and motor imagery of the stroke-affected hand were performed by 8 and 46 patients, respectively. EEG data from 11 patients who gave further consent to perform motor imagery were also collected for second calibration and third independent test sessions conducted on separate days. Off-line accuracies of classifying the two classes of EEG from finger tapping or motor imagery of the stroke-affected hand versus the EEG from background rest were then assessed and compared to 16 healthy subjects. The mean off-line accuracy of detecting motor imagery by the 46 patients (mu=0.74) was significantly lower than finger tapping by 8 patients (mu=0.87, p=0.008), but not significantly lower than motor imagery by healthy subjects (mu=0.78, p=0.23). Six stroke patients performed motor imagery at chance level, and no correlation was found between the accuracies of detecting motor imagery and their motor impairment in terms of Fugl-Meyer Assessment (p=0.29). The off-line accuracies of the 11 patients in the second session (mu=0.76) were not significantly different from the first session (mu=0.72, p=0.16), or from the on-line accuracies of the third independent test session (mu=0.82, p=0.14). Hence this study showed that the majority of stroke patients could use EEG-based motor imagery BCI.

Measurement of passive ankle stiffness in subjects with chronic hemiparesis using a novel ankle robot

Our objective in this study was to assess passive mechanical stiffness in the ankle of chronic hemiparetic stroke survivors and to compare it with those of healthy young and older (age-matched) individuals. Given the importance of the ankle during locomotion, an accurate estimate of passive ankle stiffness would be valuable for locomotor rehabilitation, potentially providing a measure of recovery and a quantitative basis to design treatment protocols. Using a novel ankle robot, we characterized passive ankle stiffness both in sagittal and in frontal planes by applying perturbations to the ankle joint over the entire range of motion with subjects in a relaxed state. We found that passive stiffness of the affected ankle joint was significantly higher in chronic stroke survivors than in healthy adults of a similar cohort, both in the sagittal as well as frontal plane of movement, in three out of four directions tested with indistinguishable stiffness values in plantarflexion direction. Our findings are comparable to the literature, thus indicating its plausibility, and, to our knowledge, report for the first time passive stiffness in the frontal plane for persons with chronic stroke and older healthy adults.

Effects of Treatment Intensity in Upper Limb Robot-Assisted Therapy for Chronic Stroke

Background and Objectives. Robot-assisted therapy (RT) is a current promising intervention in stroke rehabilitation, but more research is warranted for examining its efficacy and the dose–benefit relation. The authors investigated the effects of higher intensity versus lower intensity RT on movements of forearm pronation–supination and wrist flexion–extension relative to conventional rehabilitation (CR) in patients poststroke for a mean of 21 months. Methods. In this pilot study, 18 patients with initial mean Fugl-Meyer Assessment (FMA) of 37 to 44 for the upper extremity were randomized to higher intensity RT, lower intensity RT, or CR intervention for 4 weeks. The dose of the higher intensity RT was twice the number of repetitions in the lower intensity RT. Outcome measures at pretreatment and posttreatment were administered to patients to evaluate beneficial and adverse effects of interventions. Primary outcomes were the FMA and Medical Research Council scale. Results. There were significant differences in motor function ( P = .04) and daily performance ( P = .03) among the 3 groups. The higher intensity RT group showed better improvement in motor function, muscle strength, performance of daily activities, and bimanual ability than the other 2 groups. The intensive RT intervention did not induce higher levels of an oxidative DNA biomarker. Conclusions. Higher intensity of RT that assists forearm and wrist movements may lead to greater improvement in motor ability and functional performance in stroke patients. A sample size of only 20 to 25 in each arm of a larger randomized controlled trial is needed to confirm the findings for similar subjects.

Clinical study of neurorehabilitation in stroke using EEG-based motor imagery brain-computer interface with robotic feedback

This clinical study investigates the ability of hemiparetic stroke patients in operating EEG-based motor imagery brain-computer interface (MI-BCI). It also assesses the efficacy in motor improvements on the stroke-affected upper limb using EEG-based MI-BCI with robotic feedback neurorehabilitation compared to robotic rehabilitation that delivers movement therapy. 54 hemiparetic stroke patients with mean age of 51.8 and baseline Fugl-Meyer Assessment (FMA) 14.9 (out of 66, higher = better) were recruited. Results showed that 48 subjects (89%) operated EEG-based MI-BCI better than at chance level, and their ability to operate EEG-based MI-BCI is not correlated to their baseline FMA (r=0.358). Those subjects who gave consent are randomly assigned to each group (N=11 and 14) for 12 1-hour rehabilitation sessions for 4 weeks. Significant gains in FMA scores were observed in both groups at post-rehabilitation (4.5, 6.2; p=0.032, 0.003) and 2-month post-rehabilitation (5.3, 7.3; p=0.020, 0.013), but no significant differences were observed between groups (p=0.512, 0.550). Hence, this study showed evidences that a majority of hemiparetic stroke patients can operate EEG-based MI-BCI, and that EEG-based MI-BCI with robotic feedback neurorehabilitation is effective in restoring upper extremities motor function in stroke.

Pediatric anklebot

In this paper we present the alpha-prototype of a novel pediatric ankle robot. This lower-extremity robotic therapy module was developed at MIT to aid recovery of ankle function in children with cerebral palsy ages 5 to 8 years old. This lower-extremity robotic module will commence pilot testing with children with cerebral palsy at Blythedale Childrens Hospital (Valhalla, NY), Bambino Gesu Children's Hospital (Rome, Italy), Riley Children's Hospital (Indianapolis, IN). Its design follows the same guidelines as our upper-extremity robots and adult anklebot designs, i.e. it is a low friction, backdriveable device with intrinsically low mechanical impedance. We show the ankle robot characteristics and stability range. We also present pilot data with healthy children to demonstrate the potential of this device.

Physically interactive robotic technology for neuromotor rehabilitation

Robotic technology can provide innovative responses to the severe challenges of providing cost-effective care to restore sensory-motor function following neurological and biomechanical injury. It may be deployed at several points on a continuum of care, to provide precisely controlled sensory-motor therapy to ameliorate disability and promote recovery of function, or to provide assistance to compensate for functions that cannot be recovered, or to replace limbs lost irretrievably. This chapter reviews recent progress using robotic technology to capitalize on neural plasticity and promote recovery after neurological injury such as stroke (cerebral vascular accident), research on brain-computer interfaces as a source of control signals for assistive technologies, and research on high-performance multiple-degree-of-freedom upper-extremity prosthetic limbs.

Comparison of visual and haptic feedback during training of lower extremities

We compared the effects of visual and haptic modalities on the adaptation capabilities of healthy subjects to the virtual environment. The visual cueing (only the reference motion is presented) and visual feedback (the reference motion as well as the current tracking deviation are presented) were provided by a real-time visualization of a virtual teacher and a virtual self - avatar, using optical measurements. The subjects had to track the virtual teacher during stepping-in-place movements. The haptic feedback was provided by the actuated gait orthosis Lokomat programmed with the same stepping movements employing an impedance control algorithm. Both setups included auditory cueing. The stepping task was performed by engaging different modalities separately as well as combined. The results showed that (1) visual feedback alone yielded better tracking of the virtual teacher than visual cueing alone, (2) haptic feedback alone yielded better tracking than any visual modality alone, (3) haptic feedback and visual feedback combined yielded better tracking than haptic feedback alone, and (4) haptic feedback combined with visual cueing did not improve tracking performance compared to haptic feedback alone. In general, we observed a better task performance with the haptic modality compared to visual modality.

A clinical study of motor imagery-based brain-computer interface for upper limb robotic rehabilitation

Non-invasive EEG-based motor imagery brain-computer interface (MI-BCI) holds promise to effectively restore motor control to stroke survivors. This clinical study investigates the effects of MI-BCI for upper limb robotic rehabilitation compared to standard robotic rehabilitation. The subjects are hemiparetic stroke patients with mean age of 50.2 and baseline Fugl-Meyer (FM) score 29.7 (out of 66, higher = better) randomly assigned to each group respectively (N = 8 and 10). Each subject underwent 12 sessions of 1-hour rehabilitation for 4 weeks. Significant gains in FM scores were observed in both groups at post-rehabilitation (4.9, p = 0.001) and 2-month post-rehabilitation (4.9, p = 0.002). The experimental group yielded higher 2-month post-rehabilitation gain than the control (6.0 versus 4.0) but no significance was found (p = 0.475). However, among subjects with positive gain (N = 6 and 7), the initial difference of 2.8 between the two groups was increased to a significant 6.5 (p = 0.019) after adjustment for age and gender. Hence this study provides evidence that BCI-driven robotic rehabilitation is effective in restoring motor control for stroke.

Stochastic estimation of human arm impedance under nonlinear friction in robot joints: a model study

The basic assumption of stochastic human arm impedance estimation methods is that the human arm and robot behave linearly for small perturbations. In the present work, we have identified the degree of influence of nonlinear friction in robot joints to the stochastic human arm impedance estimation. Internal model based impedance control (IMBIC) is then proposed as a means to make the estimation accurate by compensating for the nonlinear friction. From simulations with a nonlinear Lugre friction model, it is observed that the reliability and accuracy of the estimation are severely degraded with nonlinear friction: below 2 Hz, multiple and partial coherence functions are far less than unity; estimated magnitudes and phases are severely deviated from that of a real human arm throughout the frequency range of interest; and the accuracy is not enhanced with an increase of magnitude of the force perturbations. In contrast, the combined use of stochastic estimation and IMBIC provides with accurate estimation results even with large friction: the multiple coherence functions are larger than 0.9 throughout the frequency range of interest and the estimated magnitudes and phases are well matched with that of a real human arm. Furthermore, the performance of suggested method is independent of human arm and robot posture, and human arm impedance. Therefore, the IMBIC will be useful in measuring human arm impedance with conventional robot, as well as in designing a spatial impedance measuring robot, which requires gearing.

Books

This book provides a wealth of information regarding the theory and practice of evaluating joint motion and muscle length. Chapters are arranged into five sections: 1 - history, basic principles and relevance of joint motion and muscle length assessment, 2 - the upper limb, 3 - the head, neck and trunk, 4 - the lower limb, and 5 - appendices, which contain sample data recording forms and a summary of the research on normative range of motion. Each chapter in sections 2 to 4 is focused on an anatomical area. These chapters provide detailed information on how to evaluate joint range of motion (or muscle length), as well as the anatomy and kinesiology theory that underpins these assessments. For example, chapter 3, ‘Measurement of ROM of the shoulder’ contains information regarding the anatomy, osteokinematics and arthrokinematics of the glenohumeral, sternoclavicular, acromioclavicular and scapulothoracic joints. Limits to motion are discussed and research is presented regarding the motion required to undertake functional activities. Techniques used to evaluate shoulder range of motion are described in detail, and include the patient position, stabilization, examiner action, goniometer alignment, alternative starting positions, and documentation procedures. Photographs are provided to increase the clarity of these descriptions. The chapters on muscle length assessment follow a similar format and all chapters are exhaustively referenced.

Robot-assisted task-specific training in cerebral palsy

Our goal was to examine the feasibility of applying therapeutic robotics to children and adults with severe to moderate impairment due to cerebral palsy (CP). Pilot results demonstrated significant gains for both groups. These results suggest that robot-mediated therapy may be an effective tool to ameliorate the debilitating effects of CP and provide new opportunities for reducing impairment and improving coordination.

Raised corticomotor excitability of M1 forearm area following anodal tDCS is sustained during robotic wrist therapy in chronic stroke

PURPOSE

Anodal transcranial direct current stimulation (tDCS) can transiently increase corticomotor excitability of intrinsic hand muscles and improve upper limb function in patients with chronic stroke. As a preliminary study, we tested whether increased corticomotor excitability would be similarly observed in muscles acting about the wrist, and remain present during robotic training involving active wrist movements, in six chronic stroke patients with residual motor deficit.

METHODS

Transcranial magnetic stimulation (TMS) generated motor evoked potentials (MEP) in the flexor carpi radialis (FCR) and provided a measure of corticomotor excitability and short-interval cortical inhibition (SICI) before and immediately after a period of tDCS (1 mA, 20 min, anode and TMS applied to the lesioned hemisphere), and robotic wrist training (1hr).

RESULTS

Following tDCS, the same TMS current strength evoked an increased MEP amplitude (mean 168 +/- 22%SEM; p < 0.05), that remained increased after robot training (166 +/- 23%; p < 0.05). Conditioned MEPs were of significantly lower amplitude relative to unconditioned MEPs prior to tDCS (62 +/- 6%, p < 0.05), but not after tDCS (89 +/- 14%, p = 0.40), or robot training (91 +/- 8%, p = 0.28), suggesting that the increased corticomotor excitability is associated with reduced intracortical inhibition.

CONCLUSION

The persistence of these effects after robotic motor training, indicates that a motor learning and retraining program can co-exist with tDCS-induced changes in cortical motor excitability, and supports the concept of combining brain stimulation with physical therapy to promote recovery after brain injury.

The effect of repeated measurements using an upper extremity robot on healthy adults

We are expanding the use of the MIT-MANUS robotics to persons with impairments due exclusively to orthopedic disorders, with no neurological deficits. To understand the reliability of repeated measurements of the robotic tasks and the potential for registering changes due to learning is critical. Purposes of this study were to assess the learning effect of repeated exposure to robotic evaluations and to demonstrate the ability to detect a change in protocol in outcome measurements. Ten healthy, unimpaired subjects (mean age = 54.1 +/- 6.4 years) performed six repeated evaluations consisting of unconstrained reaching movements to targets and circle drawing (with and without a visual template) on the MITMANUS. Reaching outcomes were aiming error, mean and peak speed, movement smoothness and duration. Outcomes for circle drawing were axis ratio metric and shoulder- elbow joint angles correlation metric (was based on a two-link model of the human arm and calculated hand path during the motions). Repeated-measures ANOVA (p < or = .05) determined if difference existed between the sessions. Intraclass correlations (R) were calculated. All variables were reliable, without learning across testing sessions. Intraclass correlation values were good to high (reaching, R > or =.80; circle drawing, R > or =.90). Robotic measurement ability to differentiate between similar but distinct tasks was demonstrated as measured by axis ratio metric (p < .001) and joint correlation metric (p = .001). Outcome measures of the MIT-MANUS proved to be reliable yet sensitive to change in healthy adults without motor learning over the course of repeated measurements.

A working model of stroke recovery from rehabilitation robotics practitioners

We reviewed some of our initial insights about the process of upper-limb behavioral recovery following stroke. Evidence to date indicates that intensity, task specificity, active engagement, and focusing training on motor coordination are key factors enabling efficacious recovery. On modeling, experience with over 400 stroke patients has suggested a working model of recovery similar to implicit motor learning. Ultimately, we plan to apply these insights in the development of customized training paradigms to enhance recovery.

Gerontechnology

Gerontechnology can help elderly people to identify and slow down the effects of the age-related modifications of the neural and musculoskeletal systems. The seven articles in this special issue address three main topics: biomechanics and motor control; wearable technologies; and assistive technologies.

The Effects on Kinematics and Muscle Activity of Walking in a Robotic Gait Trainer During Zero-Force Control

"Assist as needed" control algorithms promote activity of patients during robotic gait training. Implementing these requires a free walking mode of a device, as unassisted motions should not be hindered. The goal of this study was to assess the normality of walking in the free walking mode of the LOPES gait trainer, an 8 degrees-of-freedom lightweight impedance controlled exoskeleton. Kinematics, gait parameters and muscle activity of walking in a free walking mode in the device were compared with those of walking freely on a treadmill. Average values and variability of the spatio-temporal gait variables showed no or small (relative to cycle-to-cycle variability) changes and the kinematics showed a significant and relevant decrease in knee angle range only. Muscles involved in push off showed a small decrease, whereas muscles involved in acceleration and deceleration of the swing leg showed an increase of their activity. Timing of the activity was mainly unaffected. Most of the observed differences could be ascribed to the inertia of the exoskeleton. Overall, walking with the LOPES resembled free walking, although this required several adaptations in muscle activity. These adaptations are such that we expect that Assist as Needed training can be implemented in LOPES.

Design and Evaluation of the LOPES Exoskeleton Robot for Interactive Gait Rehabilitation

This paper introduces a newly developed gait rehabilitation device. The device, called LOPES, combines a freely translatable and 2-D-actuated pelvis segment with a leg exoskeleton containing three actuated rotational joints: two at the hip and one at the knee. The joints are impedance controlled to allow bidirectional mechanical interaction between the robot and the training subject. Evaluation measurements show that the device allows both a "patient-in-charge" and "robot-in-charge" mode, in which the robot is controlled either to follow or to guide a patient, respectively. Electromyography (EMG) measurements (one subject) on eight important leg muscles, show that free walking in the device strongly resembles free treadmill walking; an indication that the device can offer task-specific gait training. The possibilities and limitations to using the device as gait measurement tool are also shown at the moment position measurements are not accurate enough for inverse-dynamical gait analysis.