Walking naturally after spinal cord injury using a brain-spine interface.

A spinal cord injury interrupts the communication between the brain and the region of the spinal cord that produces walking, leading to paralysis1,2. Here, we restored this communication with a digital bridge between the brain and spinal cord that enabled an individual with chronic tetraplegia to stand and walk naturally in community settings. This brain-spine interface (BSI) consists of fully implanted recording and stimulation systems that establish a direct link between cortical signals3 and the analogue modulation of epidural electrical stimulation targeting the spinal cord regions involved in the production of walking4-6. A highly reliable BSI is calibrated within a few minutes. This reliability has remained stable over one year, including during independent use at home. The participant reports that the BSI enables natural control over the movements of his legs to stand, walk, climb stairs and even traverse complex terrains. Moreover, neurorehabilitation supported by the BSI improved neurological recovery. The participant regained the ability to walk with crutches overground even when the BSI was switched off. This digital bridge establishes a framework to restore natural control of movement after paralysis.

Kinesiology Taping in Duchenne Muscular Dystrophy: Acute Effects on Performance, Gait Characteristics, and Balance.

AIM: This study was aimed to investigate the acute effects of kinesiology taping (KT) on physical performance, gait characteristics, and balance in early-stage Duchenne Muscular Dystrophy (DMD). METHOD: Forty-five children at early functional level of DMD were included. 6-minute walk test (6MWT), and timed performance tests were performed; gait characteristics, and balance were assessed before and one hour after taping. KT was applied to bilateral quadriceps and tibialis anterior muscles. The comparison of assessments was performed by using Wilcoxon Signed Ranks test. RESULTS: Significant increase in the distance of 6MWT, decrease in the duration of descending 4 steps, and 10 m walk timed performance tests, improvements in all of the gait characteristics, and balance were determined after taping (p < .05). CONCLUSIONS: KT has positive acute effects on performance and gait of children with DMD at early functional level which encourages therapists to use KT as a complementary approach in rehabilitation programs.

A Review of Functional Electrical Stimulation Treatment in Spinal Cord Injury.

Functional electrical stimulation (FES) has been widely adopted to elicit muscle contraction in rehabilitation training after spinal cord injury (SCI). Conventional FES modalities include stimulations coupled with rowing, cycling, assisted walking and other derivatives. In this review, we studied thirteen clinical reports from the past 5 years and evaluated the effects of various FES aided rehabilitation plans on the functional recovery after SCI, highlighting upper and lower extremity strength, cardiopulmonary function, and balder control. We further explored potential mechanisms of FES using the Hebbian theory and lumbar locomotor central pattern generators. Overall, FES can be used to improve respiration, circulation, hand strength, mobility, and metabolism after SCI.

Distributed Repetitive Learning Control for Cooperative Cadence Tracking in Functional Electrical Stimulation Cycling.

Closed-loop control of functional electrical stimulation coupled with motorized assistance to induce cycling is a rehabilitative strategy that can improve the mobility of people with neurological conditions (NCs). However, robust control methods, which are currently pervasive in the cycling literature, have limited effectiveness due to the use of high stimulation intensity leading to accelerated fatigue during cycling protocols. This paper examines the design of a distributed repetitive learning controller (RLC) that commands an independent learning feedforward term to each of the six stimulated lower-limb muscle groups and an electric motor during the tracking of a periodic cadence trajectory. The switched controller activates lower limb muscles during kinematic efficient regions of the crank cycle and provides motorized assistance only when most needed (i.e., during the portions of the crank cycle where muscles evoke a low torque output). The controller exploits the periodicity of the desired cadence trajectory to learn from previous control inputs for each muscle group and electric motor. A Lyapunov-based stability analysis guarantees asymptotic tracking via an invariance-like corollary for nonsmooth systems. The switched distributed RLC was evaluated in experiments with seven able-bodied individuals and five participants with NCs. A mean root-mean-squared cadence error of 3.58 ± 0.43 revolutions per minute (RPM) (0.07 ± 7.35% average error) and 4.26 ± 0.84 RPM (0.1 ± 8.99% average error) was obtained for the healthy and neurologically impaired populations, respectively.

Effects of training with a neuro-mechano stimulator rehabilitation bicycle on functional recovery and paired-reflex depression of the soleus in individuals with incomplete paralysis: a proof-of-principle study.

Aim: The present study describes the training effects of a novel motorized bicycle-like device for individuals with incomplete spinal cord injury. Methods: Participants were five individuals with motor incomplete spinal cord injury (56 ± 7 years). Four of five participants received two 30-min sessions of training: one with, and one without, mechanical stimulation on the plantar surface of the foot; soleus paired H-reflex depression was examined before and after each session. Three of five participants received 24 sessions of 30-min of training (long-training). Following the long-training, balance, walking and spasticity improvements were assessed using validated clinical outcome measures, in addition to the H-reflex assessment. Results: One cycling session with mechanical stimulation yielded 14% and 32% more reflex depression in participants with moderate spasticity (n = 2/4). The same trend was not observed in non-spastic participants (n = 2/4). All participants who participated in the long-training had spasticity and showed reduced spasticity, improved walking speed, endurance and balance. Conclusions: Overall, participants with spasticity showed increased soleus H-reflex suppression after one training session with mechanical stimulation and reduced spasticity scores after long training. We interpret this as evidence that the training influenced both presynaptic and postsynaptic inhibitory mechanisms acting on soleus motoneurons. Therefore, this training has the potential to be a non-invasive complementary therapy to reduce spasticity after incomplete spinal cord injury.

Neuromodulation for Functional Electrical Stimulation.

This article describes the application of neuromodulation in different ways to motor recovery, to replace lost function, or to improve function of organ systems for those who have experienced spinal cord injury or stroke. Multiple devices have been developed and are currently available for use whereas others are still in the experimental stage. Multiple uses of neuromodulation are described.

Rehabilitative devices for a top-down approach.

INTRODUCTION: In recent years, neurorehabilitation has moved from a 'bottom-up' to a 'top down' approach. This change has also involved the technological devices developed for motor and cognitive rehabilitation. It implies that during a task or during therapeutic exercises, new 'top-down' approaches are being used to stimulate the brain in a more direct way to elicit plasticity-mediated motor re-learning. This is opposed to 'Bottom up' approaches, which act at the physical level and attempt to bring about changes at the level of the central neural system. AREAS COVERED: In the present unsystematic review, we present the most promising innovative technological devices that can effectively support rehabilitation based on a top-down approach, according to the most recent neuroscientific and neurocognitive findings. In particular, we explore if and how the use of new technological devices comprising serious exergames, virtual reality, robots, brain computer interfaces, rhythmic music and biofeedback devices might provide a top-down based approach. EXPERT COMMENTARY: Motor and cognitive systems are strongly harnessed in humans and thus cannot be separated in neurorehabilitation. Recently developed technologies in motor-cognitive rehabilitation might have a greater positive effect than conventional therapies.

A technical concept of a computer game for patients with Parkinson's disease - a new form of PC-based physiotherapy.

Background: At present, there are no meaningful and sophisticated computer games that simultaneously allow the treatment of movement disorders such as Parkinson's syndrome. In particular, there are no systems to consider the severity of the disease and the physical skills of the patient. Methods: A computer game using the Microsoft Kinect as markerless sensor for the 3 D recognition of the patient's movement was developed to support the rehabilitation. The scenario of a basketball game was created after determining that the movement like throwing a ball and the correct posture of the body are important. A study based on system usability was performed with 15 patients to evaluate the system. Results: The technical feasibility of a computer-assisted training system for supporting patients with Parkinson's disease has been demonstrated. No markers on the patient are required for movement detection and allow a user-friendly handling. Regarding the usability study, the patients were accepting of such a system and its at-home use and symptoms like 'freezing' and the Pisa syndrome can be treated. Conclusions: The physiotherapist can be assisted by the developed rehabilitation system. An objective measurement of the patient's training progress delivers valuable information to adjust the training sessions for every patient individually. Due to its modular character, the system can also be applied to other diseases or sports injuries and offers the basis for further development.

Advances in Automation Technologies for Lower Extremity Neurorehabilitation: A Review and Future Challenges.

The world is experiencing an unprecedented, enduring, and pervasive aging process. With more people who need walking assistance, the demand for lower extremity gait rehabilitation has increased rapidly over the years. The current clinical gait rehabilitative training requires heavy involvement of both medical doctors and physical therapists, and thus, are labor intensive, subjective, and expensive. To address these problems, advanced automation techniques, especially along with the proliferation of smart sensing and actuation devices and big data analytics platforms, have been introduced into this field to make the gait rehabilitation convenient, efficient, and personalized. This survey paper provides a comprehensive review on recent technological advances in wearable sensors, biofeedback devices, and assistive robots. Empowered by the emerging networking and computing technologies in the big data era, these devices are being interconnected into smart and connected rehabilitation systems to provide nonintrusive and continuous monitoring of physical and neurological conditions of the patients, perform complex gait analysis and diagnosis, and allow real-time decision making, biofeedback, and control of assistive robots. For each technology category, a detailed comparison among the existing solutions is provided. A thorough discussion is also presented on remaining open problems and future directions to further improve the safety, efficiency, and usability of the technologies.

Position and torque control via rehabilitation robot and functional electrical stimulation.

Two common rehabilitation therapies for individuals possessing neurological conditions are functional electrical stimulation (FES) and robotic assistance. This paper focuses on combining the two rehabilitation strategies for use on the biceps brachii muscle group. FES is used to elicit muscle contractions to actuate the forearm and a rehabilitation robot is used to challenge the muscle group in its efforts. Two controllers were developed and implemented to accomplish the multifaceted objective, both of which achieve global exponential stability for position and torque tracking as proven through a Lyapunov stability analysis. Experiments performed on one able bodied individual demonstrate an average RMS error of 5.8 degrees for position tracking and 0.40 Newton-meters for torque tracking.

Event-based control for sit-to-stand transition using a wearable exoskeleton.

Sit-to-stand transition is an essential step in a lower limb rehabilitation therapy, mainly for assisting the patient to transit from wheel chair to the next level of therapy. A mixed stiffness-damping control adaptation is proposed for this task which will help in reaching the final position with a constant velocity. A combination of control model is proposed to ensure the initiation and the final stage of the transition, such as to ensure stability and to maintain the equilibrium. The combined control model helps in reaching the goal position with equal participation from the user. For patient studies, such as with paraplegic patients, a combinational control model with muscle stimulation can be included to provide a complete assistance. The role of muscle stimulation and joint movement assistance is also considered in this control model. Further, final stage of this transition must ensure keeping or helping the user to maintain the upright position.

Neurostimulation Strategy for Stress Urinary Incontinence.

We have developed a percutaneously implantable and wireless microstimulator (NuStim) to exercise the pelvic floor muscles for the treatment of stress urinary incontinence. It produces a wide range of charge-regulated electrical stimulation pulses and trains of pulses using a simple electronic circuit that receives power and timing information from an externally generated RF magnetic field. The complete system was validated in vitro and in vivo in preclinical studies demonstrating that the NuStim can be successfully implanted into an effective, low threshold location, and the implant can be operated chronically to produce effective and well-tolerated contractions of skeletal muscle.

Hybrid Assistive Neuromuscular Dynamic Stimulation Therapy: A New Strategy for Improving Upper Extremity Function in Patients with Hemiparesis following Stroke.

Hybrid Assistive Neuromuscular Dynamic Stimulation (HANDS) therapy is one of the neurorehabilitation therapeutic approaches that facilitates the use of the paretic upper extremity (UE) in daily life by combining closed-loop electromyography- (EMG-) controlled neuromuscular electrical stimulation (NMES) with a wrist-hand splint. This closed-loop EMG-controlled NMES can change its stimulation intensity in direct proportion to the changes in voluntary generated EMG amplitudes recorded with surface electrodes placed on the target muscle. The stimulation was applied to the paretic finger extensors. Patients wore a wrist-hand splint and carried a portable stimulator in an arm holder for 8 hours during the daytime. The system was active for 8 hours, and patients were instructed to use their paretic hand as much as possible. HANDS therapy was conducted for 3 weeks. The patients were also instructed to practice bimanual activities in their daily lives. Paretic upper extremity motor function improved after 3 weeks of HANDS therapy. Functional improvement of upper extremity motor function and spasticity with HANDS therapy is based on the disinhibition of the affected hemisphere and modulation of reciprocal inhibition. HANDS therapy may offer a promising option for the management of the paretic UE in patients with stroke.

Smart Gait-Aid Glasses for Parkinson's Disease Patients.

Parkinson's disease (PD) is a chronic progressive disease caused by loss of dopaminergic neurons in the substantia nigra, degenerating the nervous system of a patient over time. Freezing of gait (FOG), which is a form of akinesia, is a symptom of PD. Meanwhile, recent studies show that the gait of PD patients experiencing FOG can be significantly improved by providing the regular visual or auditory patterns for the patients. In this paper, we propose a gait-aid system built upon smart glasses. Our system continuously monitors the gait and so on of a PD patient to detect FOG, and upon detection of FOG it projects visual patterns on the glasses as if the patterns were actually on the floor. Conducting experiments involving ten PD patients, we demonstrate that our system achieves the accuracy of 92.86 % in detecting FOG episodes and that it improves the gait speed and stride length of PD patients by 15.3  âˆ¼  37.2% and 18.7   âˆ¼  31.7%, respectively.

A Portable Sensory Augmentation Device for Balance Rehabilitation Using Fingertip Skin Stretch Feedback.

Neurological disorders are the leading causes of poor balance. Previous studies have shown that biofeedback can compensate for weak or missing sensory information in people with sensory deficits. These biofeedback inputs can be easily recognized and converted into proper information by the central nervous system (CNS), which integrates the appropriate sensorimotor information and stabilizes the human posture. In this study, we proposed a form of cutaneous feedback which stretches the fingertip pad with a rotational contactor, so-called skin stretch. Skin stretch at a fingertip pad can be simply perceived and its small contact area makes it favored for small wearable devices. Taking advantage of skin stretch feedback, we developed a portable sensory augmentation device (SAD) for rehabilitation of balance. SAD was designed to provide postural sway information through additional skin stretch feedback. To demonstrate the feasibility of the SAD, quiet standing on a force plate was evaluated while sensory deficits were simulated. Fifteen healthy young adults were asked to stand quietly under six sensory conditions: three levels of sensory deficits (normal, visual deficit, and visual + vestibular deficits) combined with and without augmented sensation provided by SAD. The results showed that augmented sensation via skin stretch feedback helped subjects correct their posture and balance, especially as the deficit level of sensory feedback increased. These findings demonstrate the potential use of skin stretch feedback in balance rehabilitation.

Movement Performance of Human-Robot Cooperation Control Based on EMG-Driven Hill-Type and Proportional Models for an Ankle Power-Assist Exoskeleton Robot.

Although the merits of electromyography (EMG)-based control of powered assistive systems have been certified, the factors that affect the performance of EMG-based human-robot cooperation, which are very important, have received little attention. This study investigates whether a more physiologically appropriate model could improve the performance of human-robot cooperation control for an ankle power-assist exoskeleton robot. To achieve the goal, an EMG-driven Hill-type neuromusculoskeletal model (HNM) and a linear proportional model (LPM) were developed and calibrated through maximum isometric voluntary dorsiflexion (MIVD). The two control models could estimate the real-time ankle joint torque, and HNM is more accurate and can account for the change of the joint angle and muscle dynamics. Then, eight healthy volunteers were recruited to wear the ankle exoskeleton robot and complete a series of sinusoidal tracking tasks in the vertical plane. With the various levels of assist based on the two calibrated models, the subjects were instructed to track the target displayed on the screen as accurately as possible by performing ankle dorsiflexion and plantarflexion. Two measurements, the root mean square error (RMSE) and root mean square jerk (RMSJ), were derived from the assistant torque and kinematic signals to characterize the movement performances, whereas the amplitudes of the recorded EMG signals from the tibialis anterior (TA) and the gastrocnemius (GAS) were obtained to reflect the muscular efforts. The results demonstrated that the muscular effort and smoothness of tracking movements decreased with an increase in the assistant ratio. Compared with LPM, subjects made lower physical efforts and generated smoother movements when using HNM, which implied that a more physiologically appropriate model could enable more natural and human-like human-robot cooperation and has potential value for improvement of human-exoskeleton interaction in future applications.

[Functional electrostimulation for drop foot treatment : Clinical outcome]. / Funktionelle Elektrostimulation zur Therapie des neurogenen Fallfußes : Klinisches Outcome.

INTRODUCTION: Neurologic paralysis of the foot due to damage to the central nervous system is primarily caused by a cerebral insult. The ankle-foot orthosis (AFO), which is the classical conservative treatment option, is associated with drawbacks, e.g., increased contractures, limited mobilization from the sitting position, and cosmetic aspects. METHODS: Functional external electrostimulation (FES) is an suitable treatment method for patients with a central lesion and intact peroneal nerve. Based on this method, the neuroprosthesis is a dynamic therapy option in the form of an implantable nerve stimulator (ActiGait® system, Otto Bock, Duderstadt, Germany) which is placed directly on the motor branch of the peroneus nerve and results in active foot lifting. The aim of the present study is to evaluate the clinical effect of the ActiGait® system with regard to its suitability for everyday use by means of gait tests with an emphasis on time-distance parameters and to compare it with the current literature. RESULTS AND CONCLUSION: In this retrospective study, the clinical results after implantation of the ActiGait® system are presented and evaluated. In summary, the implantation of a neuroprosthesis in patients with stroke-related drop foot represents a sensible and promising therapy option.

Assistive Control System for Upper Limb Rehabilitation Robot.

This paper presents an assistive control system with a special kinematic structure of an upper limb rehabilitation robot embedded with force/torque sensors. A dynamic human model integrated with sensing torque is used to simulate human interaction under three rehabilitation modes: active mode, assistive mode, and passive mode. The hereby proposed rehabilitation robot, called NTUH-ARM, provides 7 degree-of- freedom (DOF) motion and runs subject to an inherent mapping between the 7 DOFs of the robot arm and the 4 DOFs of the human arm. The Lyapunov theory is used to analyze the stability of the proposed controller design. Clinical trials have been conducted with six patients, one of which acts as a control. The results of these experiments are positive and STREAM assessment by physical therapists also reveals promising results.

Semiparametric Identification of Human Arm Dynamics for Flexible Control of a Functional Electrical Stimulation Neuroprosthesis.

We present a method to identify the dynamics of a human arm controlled by an implanted functional electrical stimulation neuroprosthesis. The method uses Gaussian process regression to predict shoulder and elbow torques given the shoulder and elbow joint positions and velocities and the electrical stimulation inputs to muscles. We compare the accuracy of torque predictions of nonparametric, semiparametric, and parametric model types. The most accurate of the three model types is a semiparametric Gaussian process model that combines the flexibility of a black box function approximator with the generalization power of a parameterized model. The semiparametric model predicted torques during stimulation of multiple muscles with errors less than 20% of the total muscle torque and passive torque needed to drive the arm. The identified model allows us to define an arbitrary reaching trajectory and approximately determine the muscle stimulations required to drive the arm along that trajectory.