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Introduction: Poliomyelitis has been considered a statutory notifiable infectious disease in Hong Kong since 1948. Approximately 15% to 80% of patients suffer from post-polio syndrome (PPS) with an increased risk of falling and chronic pain. Most of them relied on the use of knee lock-type orthoses as aids. This study aimed to evaluate the effect of using a custom-fit knee robotic orthosis on their gait performance. Materials and Methods: A case series report was used for this study on a group of individuals suffering from chronic PPS who used orthoses and had a history of falling. A knee robotic orthosis was custom-fit for eight sessions of walking practice. Assessments included laboratory gait analysis, functional measures, and subjective ratings of exertional level. Pain responses were recorded to evaluate the effect of using the knee robotic orthosis on participants' gait performance. Results: Five participants completed the study in using the knee robotic orthosis. All achieved reduction in shoulder tilting and trunk swaying movement on walking at the anterior-posterior and the medial-lateral direction. A total of 80% of the study participants achieved reduction in trunk rotation movement, lower-limb circumduction, and hip hiking movement on the affected side on walking. All study participants were able to demonstrate improvement in their gait symmetry after using the knee robotic orthosis as reflected by the symmetric index improvement of kinematics. The rate of perceived exertion and the visual analog scale of pain in all study participants were reported lower when they used the knee robotic orthosis. However, the 10-m walking time achieved was longer. Conclusions: The knee robotic orthosis had a positive effect on remediating the abnormal kinematics of PPS patients using conventional lock-knee orthosis after eight sessions of training practice. Reduction in the limping gait pattern and improvement in gait symmetry was achieved in using a knee robotic orthosis for walking. The chronic pain response and the physical exertional level on walking were also reduced. However, the walking speed achieved was slower. Clinical Relevance: The application of the knee robotic orthosis for walking assist is new to most of the PPS patients. The positive outcomes achieved merit further research for future clinical practice. [ABSTRACT FROM AUTHOR]

Stroke has a considerable incidence in the world population and would cause sequelae in the upper limbs. One way to increase the efficiency in the rehabilitation process of patients with these sequelae is through robot-assisted therapy. The present study developed a portable robotic orthosis called Pinotti Portable Robotic Exoskeleton (PPRE) and validated its functioning in clinical tests. The static and dynamic parts of the device modules are described. Design issues, such as heavyweight and engine positioning, have been optimized. The implementation of control was through a smartphone application that communicates with a microcontroller to perform desired movements. Four individuals with motor impairment of the upper limbs due to stroke performed clinical tests to validate the device. Participants did not mention pain, discomfort, tingling, and paresthesia. The robotic device showed the ability to perform the flexion and extension movements of the fingers and elbow. The PPRE was confirmed to be adequate and functional at different levels of motor impairment assessed. The orthosis presented advantages over the currently existing devices, concerning its biomechanical functioning, portability, comfort, and versatility. Thus, the apparatus has the great innovative potential to become a device for home use, serving as an aid to the therapist and facilitating the rehabilitation of patients after an injury. In a larger sample, future studies are needed to assess the effect of a robotic orthosis on the level of rehabilitation in individuals with upper limb impairment. [ABSTRACT FROM AUTHOR]

Gait modes, such as level walking, stair ascent/descent, and ramp ascent/descent, show different lower-limb kinematic and kinetic characteristics. Therefore, an accurate detection of these modes is critical for a wearable robot to provide appropriate power assistance. In this paper, a fast gait-mode-detection method based on a body sensor system is proposed. A fuzzy logic algorithm is used to estimate the likelihoods of gait modes in real time. Since the proposed fast gait mode detection makes it possible to select appropriate kinematic and kinetic models for each gait mode, assistive torques required for assisting the human motions can be obtained more naturally and immediately. The proposed methods are all verified by experiments with a lower-limb exoskeletal assistive robot with transparent actuation by series elastic actuators, called the exoskeletal robotic orthosis for walking assistance. Four healthy subjects participated in the experiments. All subjects were asked to perform different gait modes using their normal and simulated abnormal gaits, i.e., blocking the knee joint of one leg during walking. Latency and success rate of gait mode detection are selected as performance criteria. The effectiveness of the proposed gait-mode-based assistive strategy is evaluated using electromyography muscular activities. [ABSTRACT FROM AUTHOR]

In the last decades, wearable powered orthoses have been introduced in the state of the art for lower-limb rehabilitation. Most of these applications are driven by electric motors. Comparing with electric motor actuators, pneumatic artificial muscle (PAM) actuators are compliant because of the elasticity of PAMs. Consequently, for more safety and comfort of lower-limb rehabilitation, a compliant robotic orthosis powered by PAMs is developed. Based on safe control, a new control method, proxy-based sliding mode control (PSMC), was introduced into rehabilitation robotics a few years ago. It combined safety and accuracy of tracking to make it suitable for the safe control of PAM actuators. As the reason of low frequency response of PAM actuators and variable loads caused by different human subjects, the fixed parameters of PSMC makes the tracking performance vary from subject to subject, and lacks robustness. This paper presents a modification of PSMC by using neural network to tune PSMC gains online, and implements both PSMC and modified PSMC control schemes in the robotic orthosis. Experimental results demonstrate that the improved PSMC method performs better on tracking with little degradation on safety for different loads and human subjects. [ABSTRACT FROM AUTHOR]

Abstract: Robot assisted gait training may help in producing rapid improvements in functional gait parameters. This paper presents new experimental results with an intrinsically compliant robotic gait training orthosis. The newly developed robotic orthosis has 6 degrees of freedom (DOFs). A trajectory tracking controller based on the boundary layer augmented sliding control (BASMC) law was implemented to guide the subject’s limbs on physiological gait trajectories. The compliance of the robotic orthosis sagittal plane hip and knee joints was also controlled, independently of the trajectory tracking control. The robotic orthosis and the control scheme were evaluated on three neurologically intact subjects walking on a treadmill. A maximum trajectory tracking error of 10° was recorded at the hip and knee sagittal plane joints. The results showed that subjects can walk in the robotic orthosis with comfort and the BASMC law was able to guide the subject’s limbs on reference physiological trajectories. [Copyright &y& Elsevier]

Abstract: A new intrinsically compliant robotic orthosis powered by pneumatic muscle actuators (PMA) was developed for treadmill training of neurologically impaired subjects. The robotic orthosis has hip and knee sagittal plane rotations actuated by antagonistic configuration of PMA. The orthosis has passive mechanisms to allow vertical and lateral translations of the trunk and a passive hip abduction/adduction joint. A foot lifter having a passive spring mechanism was used to ensure sufficient foot clearance during swing phase. A trajectory tracking controller was implemented to evaluate the performance of the robotic orthosis on a healthy subject. The results show that the robotic orthosis is able to perform the treadmill training task by providing sufficient torques to achieve physiological gait patterns and a realistic stepping experience. The orthosis is a new addition to the rapidly advancing field of robotic orthoses for treadmill training. [Copyright &y& Elsevier]

Highlights: [•] We propose a new anticipatory assistance-as-needed robotic control algorithm. [•] The control algorithm adapts its behavior to the patient dysfunctional profile. [•] The algorithm anticipates to trajectory deviations to encourage neural plasticity. [•] We validated the proposed algorithm throughout a robotic simulator. [ABSTRACT FROM AUTHOR]

Lower limb rehabilitation robots based on linkage-based mechanisms have recently drawn significant attention in the field due to their numerous advantages. The control of previously proposed linkage-based gait rehabilitation robotic orthoses has been achieved using constant speed control without consideration for the interaction forces. However, such an approach can be harmful to people with stroke since the level of disability varies among individuals, and it may cause potential injuries when excessive force is applied by the robot. To overcome this limitation and improve the rehabilitation process, it is necessary to recognize the force exerted by the person during walking and adjust the robot's assistive torque accordingly, to provide synchronized motion. Thus, in this work, a human-cooperative approach based on a stiffness control strategy for the six-bar linkage-based gait rehabilitation robot is presented. The proposed methodology can serve as a solid foundation for developing a human-cooperative approach for linkage-based lower limb rehabilitation robotic orthoses. The control was validated and tested with eight healthy human subjects. As a result, customized robotic assistance with this mechanism can be provided during training to meet the individual needs of stroke patients, which can lead to increased engagement and contribution, thus improving treatment outcomes. [ABSTRACT FROM AUTHOR]

This paper presents newly developed algorithms for automatic adaptation of motion for a robotic rehabilitation device. The algorithms adapt the gait pattern of patients that walk on a treadmill. Three different algorithms were developed. The first one is based on inverse dynamics and online minimization of the human-machine interaction torque. The second one is based on direct dynamics and estimation of the desired variation in the gait-pattern acceleration. The third algorithm is based on impedance control and direct adaptation of the gait pattern angular trajectories. The algorithms were tested and compared in computer simulations and actual experiments on healthy subjects and patients. In simulations, all algorithms have adapted the gait pattern toward the desired one, which led to a greater than 40% reduction of interaction torques. The impedance-control-based algorithm performed best in the experiments. [ABSTRACT FROM AUTHOR]

Abstract--Recent studies have confirmed that regular treadmill training can improve walking capabilities in incomplete spinal cord-injured subjects. At the beginning of this training the leg movements of the patients have to be assisted by physiotherapists during gait on the moving treadmill. The physical capabilities and the individual experience of the therapists usually limit this training. A driven gait orthosis (DGO) has been developed that can move the legs of a patient in a physiological way on the moving treadmill. The orthosis is adjustable in size so different patients can use it. Actuators at the knee and hip joints are controlled by a position controller. With the DGO the legs of patients with different degrees of paresis and spasticity could be trained for more than half an hour, and physiological gait patterns were obtained. [ABSTRACT FROM AUTHOR]

Recent studies have confirmed that regular treadmill training can improve walking capabilities in incomplete spinal cord-injured subjects. At the beginning of this training the leg movements of the patients have to be assisted by physiotherapists during gait on the moving treadmill. The physical capabilities and the individual experience of the therapists usually limit this training. A driven gait orthosis (DGO) has been developed that can move the legs of a patient in a physiological way on the moving treadmill. The orthosis is adjustable in size so different patients can use it. Actuators at the knee and hip joints are controlled by a position controller. With the DGO the legs of patients with different degrees of paresis and spasticity could be trained for more than half an hour, and physiological gait patterns were obtained. [ABSTRACT FROM AUTHOR]

In severely affected stroke survivors, cortico-muscular control is disturbed and volitional upper limb movements often absent. Mental rehearsal of the impaired movement in conjunction with sensory feedback provision are suggested as promising rehabilitation exercises. Knowledge about the underlying neural processes, however, remains vague. In male and female chronic stroke patients with hand paralysis, a brain-computer interface controlled a robotic orthosis and turned sensorimotor β-band desynchronization during motor imagery (MI) of finger extension into contingent hand opening. Healthy control subjects performed the same task and received the same proprioceptive feedback with a robotic orthosis or visual feedback only. Only when proprioceptive feedback was provided, cortico-muscular coherence (CMC) increased with a predominant information flow from the sensorimotor cortex to the finger extensors. This effect (1) was specific to the β frequency band, (2) transferred to a motor task (MT), (3) was proportional to subsequent corticospinal excitability (CSE) and correlated with behavioral changes in the (4) healthy and (5) poststroke condition; notably, MIrelated enhancement of β-band CMC in the ipsilesional premotor cortex correlated with motor improvements after the intervention. In the healthy and injured human nervous system, synchronized activation of motor-related cortical and spinal neural pools facilitates, in accordance with the communication-through-coherence hypothesis, cortico-spinal communication and may, thereby, be therapeutically relevant for functional restoration after stroke, when voluntary movements are no longer possible. [ABSTRACT FROM AUTHOR]

Introduction/Background Gait training is one of the main objectives in rehabilitation of motor incomplete spinal cord injury (SCI). There are different modalities of locomotion training, being the robotic orthosis among them, and offering until now, positive outcomes. However there is still a lack of evidence of the optimal training characteristics. Objective To determine the effect of two different training programs with robotic gait orthosis for patients with chronic motor incomplete SCI. Material and method Study design: randomized, blinded to the observer, clinical trial. Patients from the National Institute of Rehabilitation (INR) with motor incomplete SCI, with at least 6 months of evolution and who were able to walk, were eligible. Patients were randomly assigned to either one of the two different training groups: 30 minutes or 60 minutes training group. Both groups received a training period of six weeks, five days a week. Assessments of gait pattern analysis with the GaitRite instrument, functional assessment with Spinal Cord Independence measure (SCIM), walking index for spinal cord injury (WISCI) and quality of life with life satisfaction questionnaire (Lisat-9); repeating such evaluations in a 6 and 12 months follow-up. Results In total, 12 participants were studied. After 30 training sessions with the robotic orthosis, both groups had significant improvements in gait as well as in SCIM, LISAT-9 and WISCI. No significant differences between groups were found. Conclusion Robotic orthosis gait training has a positive effect improving gait pattern in incomplete SCI. Until now, there are no significant differences between a 30 minutes and a 60 minutes-training program. [ABSTRACT FROM AUTHOR]

It is a common hypothesis in the field of robot-assisted gait rehabilitation that the active involvement and voluntary participation of neurologically impaired subjects in the robotic gait training process may enhance the outcomes of such therapy. An adaptive seamless assist-as-needed (AAN) control scheme was developed for the robotic gait training. The AAN control scheme learns in real time the disability level of human subjects based on the trajectory tracking errors and adapts the robotic assistance accordingly. The overall AAN control architecture works on the basis of a robust adaptive control approach. The performance of seamless AAN control scheme was evaluated during treadmill training with a compliant robotic orthosis having six degrees of freedom. Two experiments, namely, trajectory following experiment and the AAN experiment were carried out to evaluate the performance of seamless adaptive AAN control scheme. It was found that the robotic orthosis is capable of guiding the subjects’ limbs on reference trajectories during the trajectory following experiment. Also, a variation in robotic assistance was recorded during the AAN experiment based on the voluntary participation of human subjects. This work is an advance on the current state of the art in the compliant actuation of robotic gait rehabilitation orthoses in the context of seamless AAN gait training. [ABSTRACT FROM AUTHOR]

This work presents the design and implementation of a reference path generator for a virtual version of a robotic orthosis based on a semi-parametric model of a neuromusculoskeletal system. The proposed generator is used to regulate the movements of the mentioned virtual orthosis (VO) as a preliminary stage in designing rehabilitation strategies. The generator considers a differential neural network (DNN) identifier, which predicts the angular positions and velocities of specific articulations in the upper limb using the raw electromyographic (EMG) signals as input. The DNN-based model is validated using experimental data from the elbow joint and the Biceps Brachii muscle collected from ten healthy participants. To regulate the movements of the VO, a controller based on the sliding mode considers the motion restrictions of the articulation of the extremity intervened by the orthosis. The proposed controller guarantees that the VO reaches a set point following a reference path related to the rEMG while the motion constraints are satisfied. The functionality of the proposed path generator was tested with a VO device. The results showed that the VO followed the angular movements of the elbow. All these results confirm the applicability of the proposed semi-parametric path generator based on a DNN. • A path generator based on a semi-parametric DNN identifier. • A path generator to obtain position and velocity from upper limb articulations. • A sliding modes controller to ensure the fulfillment of state constraints. • A novel tool to regulate the motion of orthotic systems. [ABSTRACT FROM AUTHOR]

Background and Objectives: While body weight support (BWS) intonation is vital during conventional gait training of neurologically challenged subjects, it is important to evaluate its effect during robot assisted gait training. In the present research we have studied the effect of BWS intonation on muscle activities during robotic gait training using dynamic simulations. Methods: Two dimensional (2-D) musculoskeletal model of human gait was developed conjointly with another 2-D model of a robotic orthosis capable of actuating hip, knee and ankle joints simultaneously. The musculoskeletal model consists of eight major muscle groups namely; soleus (SOL), gastrocnemius (GAS), tibialis anterior (TA), hamstrings (HAM), vasti (VAS), gluteus maximus (GLU), uniarticular hip flexors (iliopsoas, IP), and Rectus Femoris (RF). BWS was provided at levels of 0, 20, 40 and 60% during the simulations. In order to obtain a feasible set of muscle activities during subsequent gait cycles, an inverse dynamics algorithm along with a quadratic minimization algorithm was implemented. Results: The dynamic parameters of the robot assisted human gait such as joint angle trajectories, ground contact force (GCF), human limb joint torques and robot induced torques at different levels of BWS were derived. The patterns of muscle activities at variable BWS were derived and analysed. For most part of the gait cycle (GC) the muscle activation patterns are quite similar for all levels of BWS as is apparent from the mean of muscle activities for the complete GC. Conclusions: Effect of BWS variation during robot assisted gait on muscle activities was studied by developing dynamic simulation. It is expected that the proposed dynamic simulation approach will provide important inferences and information about the muscle function variations consequent upon a change in BWS during robot assisted gait. This information shall be quite important while investigating the influence of BWS intonation on neuromuscular parameters of interest during robotic gait training. [ABSTRACT FROM AUTHOR]

Background: Transfemoral amputation is a serious intervention that alters the locomotion pattern, leading to secondary disorders and reduced quality of life. The outcomes of current gait rehabilitation for TFAs seem to be highly dependent on factors such as the duration and intensity of the treatment and the age or etiology of the patient. Although the use of robotic assistance for prosthetic gait rehabilitation has been limited, robotic technologies have demonstrated positive rehabilitative effects for other mobility disorders and may thus offer a promising solution for the restoration of healthy gait in TFAs. This study therefore explored the feasibility of using a bilateral powered hip orthosis (APO) to train the gait of community-ambulating TFAs and the effects on their walking abilities.Methods: Seven participants (46-71 years old with different mobility levels) were included in the study and assigned to one of two groups (namely Symmetry and Speed groups) according to their prosthesis type, mobility level, and prior experience with the exoskeleton. Each participant engaged in a maximum of 12 sessions, divided into one Enrollment session, one Tuning session, two Assessment sessions (conducted before and after the training program), and eight Training sessions, each consisting of 20 minutes of robotically assisted overground walking combined with additional tasks. The two groups were assisted by different torque-phase profiles, aiming at improving symmetry for the Symmetry group and at maximizing the net power transferred by the APO for the Speed group. During the Assessment sessions, participants performed two 6-min walking tests (6mWTs), one with (Exo) and one without (NoExo) the exoskeleton, at either maximal (Symmetry group) or self-selected (Speed group) speed. Spatio-temporal gait parameters were recorded by commercial measurement equipment as well as by the APO sensors, and metabolic efficiency was estimated via the Cost of Transport (CoT). Additionally, kinetic and kinematic data were recorded before and after treatment in the NoExo condition.Results: The one-month training protocol was found to be a feasible strategy to train TFAs, as all participants smoothly completed the clinical protocol with no relevant mechanical failures of the APO. The walking performance of participants improved after the training. During the 6mWT in NoExo, participants in the Symmetry and Speed groups respectively walked 17.4% and 11.7% farther and increased walking speed by 13.7% and 17.9%, with improved temporal and spatial symmetry for the former group and decreased energetic expenditure for the latter. Gait analysis showed that ankle power, step width, and hip kinematics were modified towards healthy reference levels in both groups. In the Exo condition metabolic efficiency was reduced by 3% for the Symmetry group and more than 20% for the Speed group.Conclusions: This study presents the first pilot study to apply a wearable robotic orthosis (APO) to assist TFAs in an overground gait rehabilitation program. The proposed APO-assisted training program was demonstrated as a feasible strategy to train TFAs in a rehabilitation setting. Subjects improved their walking abilities, although further studies are required to evaluate the effectiveness of the APO compared to other gait interventions. Future protocols will include a lighter version of the APO along with optimized assistive strategies. [ABSTRACT FROM AUTHOR]

Human hands and fingers are of significant importance in people's capacity to perform daily tasks (touching, feeling, holding, gripping, writing). However, about 1.5 million people around the world are suffering from injuries, muscle and neurological disorders, a loss of hand function, or a few fingers due to stroke. This paper focuses on newly developed finger orthotics, which is thin, adaptable to the length of each finger and low energy costs. The aim of the study is to design and control a new robotic orthosis using for daily rehabilitation therapy. Kinematic and dynamic analysis of orthosis was calculated and the joint regulation of orthosis was obtained. The Lagrange method was used to obtain dynamics, and the Denavit–Hartenberg (D–H) method was used for kinematic analysis of hand. In order to understand its behavior, the robotic finger orthotics model was simulated in MatLab/Simulink. The simulation results show that the efficiency and robustness of proportional integral derivative (PID) controller are appropriate for the use of robotic finger orthotics. [ABSTRACT FROM AUTHOR]

BACKGROUND: Due to physical and psychosocial issues associated with long-term sitting in a wheelchair, devising new ways to facilitate upright mobility is a key issue in rehabilitation medicine. Wearable Power-Assist Locomotor (WPAL) is a motorized orthosis and is developed for providing independent and comfortable walking for paraplegic patients. METHODS: The WPAL consists of a wearable robotic orthosis and custom walker. To facilitate alternate usage with a wheelchair, the wearable robotic orthosis is based on a medial system with motors located at the bilateral hip, knee and ankle joints to reduce the increase in heart rate during gait. The gait parameters include stride length, toe clearance height, swing time, double support time, etc. (gait speed: up to 1.3 km/h). Independent gait with the walker can be learned through a five-stage gait exercise sequence. The first two stages are stepping and gait exercises with parallel bars. The third stage is gait exercise on treadmill. The subsequent two stages are gait exercise with walker. RESULTS: Seven motor-complete paraplegic patients (spinal cord functional levels: T6-T12) participated. Through a series of exercises, all users achieved independent gait on a level floor (Functional Ambulation Categories: 4). The mean duration and distance of consecutively walking were 14.1 ± 11.4 minutes and 165.6 ± 202.6 m, respectively. The most competent user was able to walk continuously for as long as 40 minutes and 640 m whereas only for 6 minutes and 107 m with a conventional orthosis. CONCLUSIONS: These results suggest that WPAL might be useful device for supporting upright walking in persons with paraplegia. [ABSTRACT FROM AUTHOR]

Volitional modulation and neurofeedback of sensorimotor oscillatory activity is currently being evaluated as a strategy to facilitate motor restoration following stroke. Knowledge on the interplay between this regional brain self-regulation, distributed network entrainment and handedness is, however, limited. In a randomized cross-over design, twenty-one healthy subjects (twelve right-handers [RH], nine left-handers [LH]) performed kinesthetic motor imagery of left (48 trials) and right finger extension (48 trials). A brain-machine interface turned event-related desynchronization in the beta frequency-band (16–22 Hz) during motor imagery into passive hand opening by a robotic orthosis. Thereby, every participant subsequently activated either the dominant (DH) or non-dominant hemisphere (NDH) to control contralateral hand opening. The task-related cortical networks were studied with electroencephalography. The magnitude of the induced oscillatory modulation range in the sensorimotor cortex was independent of both handedness (RH, LH) and hemispheric specialization (DH, NDH). However, the regional beta-band modulation was associated with different alpha-band networks in RH and LH: RH presented a stronger inter- hemispheric connectivity, while LH revealed a stronger intra- hemispheric interaction. Notably, these distinct network entrainments were independent of hemispheric specialization. In healthy subjects, sensorimotor beta-band activity can be robustly modulated by motor imagery and proprioceptive feedback in both hemispheres independent of handedness. However, right and left handers show different oscillatory entrainment of cortical alpha-band networks during neurofeedback. This finding may inform neurofeedback interventions in future to align them more precisely with the underlying physiology. [ABSTRACT FROM AUTHOR]

Standard brain stimulation protocols modify human motor cortex excitability by modulating the gain of the activated corticospinal pathways. However, the restoration of motor function following lesions of the corticospinal tract requires also the recruitment of additional neurons to increase the net corticospinal output. For this purpose, we investigated a novel protocol based on brain state- dependent paired associative stimulation. Motor imagery (MI)-related electroencephalography was recorded in healthy males and females for brain state-dependent control of both cortical and peripheral stimulation in a brain-machine interface environment. State-dependency was investigated with concurrent, delayed, and independent stimulation relative to the Ml task. Specifically, sensorimotor event-related desynchronization (ERD) in the jU-band (16 -22 Hz) triggered peripheral stimulation through passive hand opening by a robotic orthosis and transcranial magnetic stimulation to the respective cortical motor representation, either synchronously or subsequently. These MI-related paradigms were compared with paired cortical and peripheral input applied independent of the brain state. Cortical stimulation resulted in a significant increase in corticospinal excitability only when applied brain state-dependently and synchronously to peripheral input. These gains were resistant to a depotentiation task, revealed a nonlinear evolution of plasticity, and were mediated via the recruitment of additional corticospinal neurons rather than via synchronization of neuronal firing. Recruitment of additional corticospinal pathways may be achieved when cortical and peripheral inputs are applied concurrently, and during J3-ERD. These findings resemble a gating mechanism and are potentially important for developing closed-loop brain stimulation for the treatment of hand paralysis following lesions of the corticospinal tract. [ABSTRACT FROM AUTHOR]

In accordance with strict requirements of portability, cheapness, and modularity, an innovative assistive device for hand disabilities has been developed and validated. This robotic orthosis is designed to be a low-cost, portable hand exoskeleton to assist people with physical disabilities in their everyday lives. Referring to hand opening disabilities, the authors have developed a methodology which, by starting from the geometrical characteristics of the patient's hand, defines the novel kinematic mechanism that better fits to the finger trajectories. The authors have validated the proposed novel mechanism by carrying out a Hand Exoskeleton System (HES) prototype, based on a single-phalanx mechanism, cable driven. The testing phase of the real prototype with a patient is currently on going. [ABSTRACT FROM PUBLISHER]

Passive dynamic walking models are capable of capturing basic properties of walking behaviours and can generate stable human-like walking without any actuation on inclined surfaces. The passive compass gait model is among the simplest of such models, consisting of a planar point mass and two stick legs. A number of different actuation methods have been proposed both for this model and its more complex extensions to eliminate the need for a sloped ground, balancing collision losses using gravitational potential energy. In this study, we introduce and investigate an extended model with series-elastic actuation at the ankle towards a similar goal, realizing stable walking on level ground. Our model seeks to capture the basic structure of how humans utilize toe push-off prior to leg liftoff, and is intended to eventually be used for controlling the ankle joint in a lower-body robotic orthosis. We derive hybrid equations of motion for this model, and show numerically through Poincaré analysis that it can achieve asymptotically stable walking on level ground for certain choices of system parameters. We then study the bifurcation regimes of period doubling with this model, leading up to chaotic walking patterns. Finally, we show that feedback control on the initial extension of the series ankle spring can be used to improve and extend system stability. [ABSTRACT FROM AUTHOR]

Self-regulation of sensorimotor oscillations is currently researched in neurorehabilitation, e.g. for priming subsequent physiotherapy in stroke patients, and may be modulated by neurofeedback or transcranial brain stimulation. It has still to be demonstrated, however, whether and under which training conditions such brain self-regulation could also result in motor gains. Thirty-two right-handed, healthy subjects participated in a three-day intervention during which they performed 462 trials of kinesthetic motor-imagery while a brain–robot interface (BRI) turned event-related β-band desynchronization of the left sensorimotor cortex into the opening of the right hand by a robotic orthosis. Different training conditions were compared in a parallel-group design: (i) adaptive classifier thresholding and contingent feedback, (ii) adaptive classifier thresholding and non-contingent feedback, (iii) non-adaptive classifier thresholding and contingent feedback, and (iv) non-adaptive classifier thresholding and non-contingent feedback. We studied the task-related cortical physiology with electroencephalography and the behavioral performance in a subsequent isometric motor task. Contingent neurofeedback and adaptive classifier thresholding were critical for learning brain self-regulation which, in turn, led to behavioral gains after the intervention. The acquired skill for sustained sensorimotor β-desynchronization correlated significantly with subsequent motor improvement. Operant learning of brain self-regulation with a BRI may offer a therapeutic perspective for severely affected stroke patients lacking residual hand function. [ABSTRACT FROM AUTHOR]

Basing on strict requirements of portability, low cost and modularity, an assistive device for hand-opening impairment, characterized by an innovative mechanism, has been developed and tested by the authors. This robotic orthosis is designed to be a low-cost and portable hand exoskeleton to assist people with hand-opening impairment in their everyday lives. The mechanism has been especially studied for this kind of applications and presents some interesting features in terms of limited encumbrances and costs. Concerning the hand-opening impairment, the authors have also developed a methodology which, starting from the geometrical characteristics of the patient’s hand, properly defines the novel kinematic mechanism that better fits the finger trajectories. The authors have tested and validated the proposed approach by building a functional Hand Exoskeleton System (HES) prototype. The preliminary testing phase of the prototype with a single subject is concluded; currently, a group of subjects is testing the proposed HES methodology in collaboration with a rehabilitation center. [ABSTRACT FROM AUTHOR]

Background: There is a need for alternative treatment options for tremor patients who do not respond well to medications or surgery, either due to side effects or poor efficacy, or that are excluded from surgery. The study aims to evaluate feasibility of a voluntary-driven, speed-controlled tremor rejection approach with individuals with pathological tremor. The suppression approach was investigated using a robotic orthosis for suppression of elbow tremor. Importantly, the study emphasizes the performance in relation to the voluntary motion.Methods: Nine participants with either Essential Tremor (ET) or Parkinson's disease (PD) were recruited and tested off medication. The participants performed computerized pursuit tracking tasks following a sinusoid and a random target, both with and without the suppressive orthosis. The impact of the Tremor Suppression Orthosis (TSO) at the tremor and voluntary frequencies was determined by the relative power change calculated from the Power Spectral Density (PSD). Voluntary motion was, in addition, assessed by position and velocity tracking errors.Results: The suppressive orthosis resulted in a 94.4% mean power reduction of the tremor (p < 0.001) - a substantial improvement over reports in the literature. As for the impact to the voluntary motion, paired difference tests revealed no statistical effect of the TSO on the relative power change (p = 0.346) and velocity tracking error (p = 0.283). A marginal effect was observed for the position tracking error (p = 0.05). The interaction torque with the robotic orthosis was small (0.62 Nm) when compared to the maximum voluntary torque that can be exerted by adult individuals at the elbow joint.Conclusions: Two key contributions of this work are first, a recently proposed approach is evaluated with individuals with tremor demonstrating high levels of tremor suppression; second, the impact of the approach to the voluntary motion is analyzed comprehensively, showing limited inhibition. This study also seeks to address a gap in studies with individuals with tremor where the impact of engineering solutions on voluntary motion is unreported. This study demonstrates feasibility of the wearable technology as an effective treatment that removes tremor with limited impediment to intentional motion. The goal for such wearable technology is to help individuals with pathological tremor regain independence in activities affected by the tremor condition. Further investigations are needed to validate the technology. [ABSTRACT FROM AUTHOR]

Brain–robot interfaces (BRI) are studied as novel interventions to facilitate functional restoration in patients with severe and persistent motor deficits following stroke. They bridge the impaired connection in the sensorimotor loop by providing brain-state dependent proprioceptive feedback with orthotic devices attached to the hand or arm of the patients. The underlying neurophysiology of this BRI neuromodulation is still largely unknown. We investigated changes of corticospinal excitability with transcranial magnetic stimulation in thirteen right-handed healthy subjects who performed 40 min of kinesthetic motor imagery receiving proprioceptive feedback with a robotic orthosis attached to the left hand contingent to event-related desynchronization of the right sensorimotor cortex in the β-band (16–22 Hz). Neural correlates of this BRI intervention were probed by acquiring the stimulus–response curve (SRC) of both motor evoked potential (MEP) peak-to-peak amplitudes and areas under the curve. In addition, a motor mapping was obtained. The specificity of the effects was studied by comparing two neighboring hand muscles, one BRI-trained and one control muscle. Robust changes of MEP amplitude but not MEP area occurred following the BRI intervention, but only in the BRI-trained muscle. The steep part of the SRC showed an MEP increase, while the plateau of the SRC showed an MEP decrease. MEP mapping revealed a distributed pattern with a decrease of excitability in the hand area of the primary motor cortex, which controlled the BRI, but an increase of excitability in the surrounding somatosensory and premotor cortex. In conclusion, the BRI intervention induced a complex pattern of modulated corticospinal excitability, which may boost subsequent motor learning during physiotherapy. [ABSTRACT FROM AUTHOR]

Background: Abnormal upper arm-forearm muscle synergies after stroke are poorly understood. We investigated whether upper arm function primes paralyzed forearm muscles in chronic stroke patients after Brain-Machine Interface (BMI)-based rehabilitation. Shaping upper arm-forearm muscle synergies may support individualized motor rehabilitation strategies. Methods: Thirty-two chronic stroke patients with no active finger extensions were randomly assigned to experimental or sham groups and underwent daily BMI training followed by physiotherapy during four weeks. BMI sessions included desynchronization of ipsilesional brain activity and a robotic orthosis to move the paretic limb (experimental group, n = 16). In the sham group (n = 16) orthosis movements were random. Motor function was evaluated with electromyography (EMG) of forearm extensors, and upper arm and hand Fugl-Meyer assessment (FMA) scores. Patients performed distinct upper arm (e.g., shoulder flexion) and hand movements (finger extensions). Forearm EMG activity significantly higher during upper arm movements as compared to finger extensions was considered facilitation of forearm EMG activity. Intraclass correlation coefficient (ICC) was used to test inter-session reliability of facilitation of forearm EMG activity. Results: Facilitation of forearm EMG activity ICC ranges from 0.52 to 0.83, indicating fair to high reliability before intervention in both limbs. Facilitation of forearm muscles is higher in the paretic as compared to the healthy limb (p<0.001). Upper arm FMA scores predict facilitation of forearm muscles after intervention in both groups (significant correlations ranged from R = 0.752, p = 0.002 to R = 0.779, p = 0.001), but only in the experimental group upper arm FMA scores predict changes in facilitation of forearm muscles after intervention (R = 0.709, p = 0.002; R = 0.827, p<0.001). Conclusions: Residual upper arm motor function primes recruitment of paralyzed forearm muscles in chronic stroke patients and predicts changes in their recruitment after BMI training. This study suggests that changes in upper arm-forearm synergies contribute to stroke motor recovery, and provides candidacy guidelines for similar BMI-based clinical practice. [ABSTRACT FROM AUTHOR]

Noninvasive brain-computer-interfaces (BCI) coupled with prosthetic devices were recently introduced in the rehabilitation of chronic stroke and other disorders of the motor system. These BCI systems and motor rehabilitation in general involve several motor tasks for training. This study investigates the neurophysiological bases of an EEG-oscillation-driven BCI combined with a neuroprosthetic device to define the specific oscillatory signature of the BCI task. Controlling movements of a hand robotic orthosis with motor imagery of the same movement generates sensorimotor rhythm oscillation changes and involves three elements of tasks also used in stroke motor rehabilitation: passive and active movement, motor imagery, and motor intention. We recorded EEG while nine healthy participants performed five different motor tasks consisting of closing and opening of the hand as follows: 1) motor imagery without any external feedback and without overt hand movement, 2) motor imagery that moves the orthosis proportional to the produced brain oscillation change with online proprioceptive and visual feedback of the hand moving through a neuroprosthetic device (BCI condition), 3) passive and 4) active movement of the hand with feedback (seeing and feeling the hand moving), and 5) rest. During the BCI condition, participants received contingent online feedback of the decrease of power of the sensorimotor rhythm, which induced orthosis movement and therefore proprioceptive and visual information from the moving hand. We analyzed brain activity during the five conditions using time-frequency domain bootstrap-based statistical comparisons and Morlet transforms. Activity during rest was used as a reference. Significant contralateral and ipsilateral event-related desynchronization of sensorimotor rhythm was present during all motor tasks, largest in contralateral-postcentral, medio-central, and ipsilateral-precentral areas identifying the ipsilateral precentral cortex as an integral part of motor regulation. Changes in task-specific frequency power compared with rest were similar between motor tasks, and only significant differences in the time course and some narrow specific frequency bands were observed between motor tasks. We identified EEG features representing active and passive proprioception (with and without muscle contraction) and active intention and passive involvement (with and without voluntary effort) differentiating brain oscillations during motor tasks that could substantially support the design of novel motor BCI-based rehabilitation therapies. The BCI task induced significantly different brain activity compared with the other motor tasks, indicating neural processes unique to the use of body actuators control in a BCI context. [ABSTRACT FROM AUTHOR]

It is important to develop a robotic orthosis or exoskeleton that can provide back-drivable and good assistive performances with lightweight structures for overground gait rehabilitation of stroke patients. In this paper, we describe a robotic knee device with a five-bar linkage to allow low-impedance voluntary knee motion within a specified rotation range during the swing phase, and to assist knee extension during the stance phase. The device can provide free motion through the five-bar linkage with 2-degree-of-freedom (DOF) actuation via the patient's shank using a linear actuator, and can assist knee extension at any controlled knee angle while bearing weight via a geared five-bar linkage with 1 DOF actuation of the linear actuator. The kinematic transition between the two modes can be implemented by contact with a circular structure and a linear link, and the resultant range of motion can be determined by the linear actuator. The kinematic weight of the device was optimized using the simple genetic algorithm to reduce the mass. The optimization cost function was based on the sum of the total link lengths and the actuator power. The optimization results reduced the total link length and motor power by 47% and 43%, respectively, compared to the initial design. We expect that the device will facilitate rehabilitation of stroke patients by allowing safe and free overground walking while providing support for stumbling. [ABSTRACT FROM PUBLISHER]

Abstract: Objective. The goal of this study was to compare the muscle activation patterns in various major leg muscles during treadmill ambulation with those exhibited during robotic-assisted walking. Background. Robotic devices are now being integrated into neurorehabilitation programs with promising results. The influence of these devices on altering naturally occurring muscle activation patterns utilized during walking have not been quantified. Methods. Muscle activity measured during 60s of walking was broken up into individual stride cycles, averaged, and normalized. The stride cycle was then broken up into seven distinct phases and the integrated muscle activity during each phase was compared between treadmill and robotic-assisted walking using a multi-factor ANOVA. Results. Significant differences in the spatial and temporal muscle activation patterns were observed across various portions of the gait cycle between treadmill and robotic-assisted walking. Activity in the quadriceps and hamstrings was significantly higher during the swing phase of Lokomat walking than treadmill walking, while activity in the ankle flexor and extensor muscles was reduced throughout most of the gait cycle in the Lokomat. Conclusions. Walking within a robotic orthosis that limits the degrees of freedom of leg and pelvis movement leads to changes in naturally occurring muscle activation patterns. Relevance: An understanding of how robotic-assisted walking alters muscle activation patterns is necessary clinically in order to establish baseline patterns against which subject’s with neurological disorders can be compared. Furthermore, this information will guide further developments in robotic devices targeting gait training. [Copyright &y& Elsevier]

STUDY DESIGN:: Clinical study on six spinal cord-injured subjects. The performance of two automatic gait-pattern adaptation algorithms for automated treadmill training rehabilitation of locomotion (called DJATA1 and DJATA2) was tested and compared in this study. OBJECTIVES:: To test the performance of the two algorithms and to evaluate the corresponding patient satisfaction. We also wanted to evaluate the motivation of the patients to train with a fixed gait pattern versus training where they can influence and change the gait pattern (gait-pattern adaptation). SETTING:: Spinal Cord Injury Center Paracare, Balgrist, Zürich, Switzerland. METHODS:: The experimental data were collected during six blinded and randomized training trials (comprising three different conditions per algorithm) split into two training sessions per patient. During the experiments, we have recorded the time courses of the six parameters describing the adaptation. Additionally, a special patient questionnaire was developed that allowed us to collect data regarding the quality, perception, speed, and required effort of the adaptation, as well as patients’ opinion that addressed their motivation. The achieved adaptation was evaluated based on the time course of adaptation parameters and based on the patient questionnaire. A statistical analysis was made in order to quantify the data and to compare the two algorithms. RESULTS:: Significant adaptation of the gait pattern took place. The patients were in most cases able to change the gait pattern to a desired one and have always perceived the adaptation. No statistically significant differences were found between the performances of the two algorithms based on the evaluated data. However, DJATA2 achieved better adaptation scores. All patients preferred treadmill training with gait-pattern adaptation. CONCLUSION:: In the future, the patients would like to train with gait-pattern adaptation. Besides the subjective opinion indicating the choice of this training modality, gait-pattern adaptation also might lead to additional improvement of the rehabilitation of locomotion as it increases and promotes active training. SPONSORSHIP:: The work was supported by The Swiss Commission for Technology and Innovation (Project No. 4005.1).Spinal Cord (2003) 41, 657-666. doi:10.1038/sj.sc.3101518 [ABSTRACT FROM AUTHOR]

Case Diagnosis: Cerebellar stroke causing significant alleviation of essential tremor with functional improvement Case Description: The patient was 88 year old male with 20 year history of essential tremor (ET) with large amplitude causing significant impairment in his speech, writing, and eating; unable to eat any liquid type of food without using a straw. The patient presented with dizziness, MRI revealed acute ischemic right cerebellar infarction with right vertebral artery dissection. His propranolol of 160mg/day was discontinued due to bradycardia. On PM&R consultation, the patient only had mild truncal ataxia with minor dysmetria, however, his limb and vocal tremor significantly alleviated with improved writing. The patient was able to bring a cup of water to his mouth without spilling, speak 150 words per minute(60-70 wpm prior) more fluidly with better breath support. Significant alleviation of tremor with improved speech and ADLs continued throughout rehab with initial FIM score being 61, and 81 at discharge. Discussions: This is a rare case in which a patient with disabling tremor was significantly improved after cerebellar infarction. Some fMRI studies showed a relative increase in cerebellar and red nuclear blood flow in some ET patients, as probably in this patient's presentation. Other studies showed that a stereotaxic or vascular lesion involving thalamus, pons, cerebellum can abolish tremor, possibly suggesting pathway between sensory-motor cortical area and cerebellum. Currently, only propranolol and primidone are established as effective for ET, however, 30 to 50% of patients are medically intractable. Psychologic factor and disabling function from ET has a lack of published data as well as poorly understood pathophysiology. Conclusions: Stroke had a treatment role in this ET patient with functional disability. Further research in modulating cerebellar blood flow or pathway and rehabilitation approaches, such as developing (robotic) orthosis and ET specific functional measurement, may provide better outcome of ET patient with functional disability. [ABSTRACT FROM AUTHOR]

BACKGROUND: Robot assisted gait training is a rapidly evolving rehabilitation practice. Various robotic orthoses have been developed during the past two decades for the gait training of patients suffering from neurologic injuries. These robotic orthoses can provide systematic gait training and reduce the work load of physical therapists. Biomechanical gait parameters can also be recorded and analysed more precisely as compared to manual physical therapy. OBJECTIVES: A review of robotic orthoses developed for providing gait training of neurologically impaired patients is provided in this paper. METHODS: Recent developments in the mechanism design and actuation methods of these robotic gait training orthoses are presented. Control strategies developed for these robotic gait training orthoses in the recent years are also discussed in detail. These control strategies have the capability to provide customised gait training according to the disability level and stage of rehabilitation of neurologically impaired subjects. RESULTS: A detailed discussion regarding the mechanism design, actuation and control strategies with potential developments and improvements is provided at the end of the paper. CONCLUSIONS: A number of robotic orthoses and novel control strategies have been developed to provide gait training according to the disability level of patients and have shown encouraging results. There is a need to develop improved robotic mechanisms, actuation methods and control strategies that can provide naturalistic gait patterns, safe human-robot interaction and customized gait training, respectively. Extensive clinical trials need to be carried out to ascertain the efficacy of these robotic rehabilitation orthoses. [ABSTRACT FROM AUTHOR]