Clinical Feasibility of Applying Immersive Virtual Reality during Robot-Assisted Gait Training for Individuals with Neurological Diseases: A Pilot Study.

Background: Immersive virtual reality has the potential to motivate and challenge patients who need and want to relearn movements in the process of neurorehabilitation.

Objective: The aim of this study was to evaluate the feasibility and user acceptance of an innovative immersive virtual reality system (head-mounted display) used in combination with robot-assisted gait training in subjects suffering from neurological diseases.

Methods: Fifteen participants suffering from cerebrovascular accident or spinal cord injury completed a single session of immersive virtual reality using a head-mounted display during a Lokomat gait session.

Cross-step detection using center-of-pressure based algorithm for real-time applications.

Background: Gait event detection is crucial for assessment, evaluation and provision of biofeedback during rehabilitation of walking. Existing online gait event detection algorithms mostly rely on add-on sensors, limiting their practicality. Instrumented treadmills offer a promising alternative by utilizing the Center of Pressure (CoP) signal for real-time gait event detection.

Real-Time Gait Event Detection with Adaptive Frequency Oscillators from a Single Head-Mounted IMU.

Accurate real-time gait event detection is the basis for the development of new gait rehabilitation techniques, especially when utilizing robotics or virtual reality (VR). The recent emergence of affordable wearable technologies, especially inertial measurement units (IMUs), has brought forth various new methods and algorithms for gait analysis. In this paper, we highlight some advantages of using adaptive frequency oscillators (AFOs) over traditional gait event detection algorithms, implemented a real-time AFO-based algorithm that estimates the gait phase from a single head-mounted IMU, and validated our method on a group of healthy subjects.

Harnessing Energy of a Treadmill for Push-Off Assistance During Walking: a Proof of Concept study.

Various approaches in ankle exoskeleton design and control have recently been proposed and implemented, but few have been able to produce devices suitable for rehabilitation in clinical environment. In a recent in-silico study, we proposed a novel device: Ankle Exoskeleton using Treadmill Actuation for Push-off assistance (AN-EXTRA-Push). Using a brake and an elastic tendon, it harnesses energy of a moving treadmill during stance phase, then releases it during push-off to aid with plantarflexion torque generation.

Harnessing Energy of a Treadmill for Push-Off Assistance During Walking: Feasibility Study.

Regaining efficient push-off is a crucial step in restitution of walking ability in impaired individuals. Inspired by the elastic nature of ankle plantarflexor muscle-tendon complex, we propose a novel rehabilitation device: Ankle Exoskeleton using Treadmill Actuation for Push-off assistance (AN-EXTRA-Push). Using a brake and an elastic tendon, it harnesses energy of a moving treadmill during stance phase, then releases it during push-off to aid with plantarflexion torque generation.

Toward improving the specificity of perturbation-based training through assessment of dynamic balancing responses: a series of N-of-1 studies in subacute stroke.

Perturbation-based balance training (PBT) has been shown to improve reactive balancing abilities in chronic stroke. To inform future investigations in the subacute phase of stroke, the objective of this series of N-of-1 studies was to investigate the range of balancing responses to unexpected mechanical perturbations applied to the pelvis during walking on an instrumented treadmill before and after PBT training. Three subacute stroke subjects were assessed on each occasion with clinical tests and biomechanical measurements following perturbations applied in forward, backward, inward and outward directions.

High-density electromyography biofeedback during robotic wrist exercises for reducing co-activation of antagonist muscles: a case report.

High-density (HD) electrodes have been introduced in research and diagnostic electromyography. Recent advances in technology offer an opportunity for using the HDEMG signal as biofeedback in stroke rehabilitation. The purpose of this case study was to test the feasibility of using two 5 × 13 electrode arrays for providing real-time HDEMG biofeedback and the preliminary outcome of combining HDEMG biofeedback with robotic wrist exercises over 4 weeks in a person who suffered a stroke 26 months earlier.

Wide Skis As a Potential Knee Injury Risk Factor in Alpine Skiing.

Alpine skis with wider waist widths have recently become more popular. With such skis, the contact point of the ground reaction force during ski turns is displaced more medially from beneath the sole of the outer ski, which may present an increased risk of injury. The aim of this study was to investigate knee joint kinetics, kinematics, and lower limb muscle activation as a function of changes of the ski waist width in a laboratory setting.

Movement strategy and EMG activities of the upper extremity at assisted reaching exercise with a 7 DOF collaborative robot.

Recovering of upper extremity functions is important for stroke patients to perform various tasks in daily life. For better rehabilitation outcomes and accurate measurement, robot assisted exercises have been developed. However, there are limited number of studies related to arm muscles activities corresponding to task complexity.

Biomechanics of In-Stance Balancing Responses Following Outward-Directed Perturbation to the Pelvis During Very Slow Treadmill Walking Show Complex and Well-Orchestrated Reaction of Central Nervous System.

Multiple strategies may be used when counteracting loss of balance during walking. Placing the foot onto a new location is not efficient when walking speed is very low. Instead medio-lateral displacement of center-of-pressure, rotation of body segments to produce a lateral ground-reaction-force, and pronounced braking of movement in the plane of progression is used.

Assessment of dynamic balancing responses following perturbations during slow walking in relation to clinical outcome measures for high-functioning post-stroke subjects.

Background: Generating appropriate balancing reactions in response to unexpected loss of balance during walking is important to prevent falls. The purpose of this study was to assess dynamic balancing responses following pushes to the pelvis in groups of post-stroke and healthy subjects.

Methods: Forty-one post-stroke subjects and forty-three healthy subjects participated in the study.

Estimation of Muscle Co-Activations in Wrist Rehabilitation After Stroke is Sensitive to Motor Unit Distribution and Action Potential Shapes.

We evaluated different muscle excitation estimation techniques, and their sensitivity to Motor Unit (MU) distribution in muscle tissue. For this purpose, the Convolution Kernel Compensation (CKC) method was used to identify the MU spike trains from High-Density ElectroMyoGrams (HDEMG). Afterwards, Cumulative MU Spike Train (CST) was calculated by summing up the identified MU spike trains.

Information and communication technology used by people with lower limb loss in Slovenia.

World demography is changing as the population ages and there are more people with disabilities having problems to stay independently at home. Innovative technologies could help extend the independence of older people living at home. As part of a collaborative project, we investigated ownership and use of information and communication technologies (ICT) among older people with lower limb loss (LLL) using questionnaires and retrospective analysis.

Emulation of hill walking and turning on Balance Assessment Robot: A preliminary study.

Gait training after stroke is often associated with rehabilitation robotics and virtual environment in order to simulate practice of different functional gait tasks. Changing direction, walking up and down the slope are important skills that need to be practiced. The aim of this preliminary study was to compare inclined treadmill walking and turning conditions with its emulations on a recently developed Balance Assessment Robot for Treadmill walking (BART) on a basis of ground reaction forces (GRF) and lower extremity electromyography (EMG).

Influence of Treadmill Speed and Perturbation Intensity on Selection of Balancing Strategies during Slow Walking Perturbed in the Frontal Plane.

Background: Common understanding is that adequate foot placement (stepping strategy) is crucial in maintaining stability during walking at normal speed. The aim of this study was to investigate strategies that humans use to cope with lateral perturbations during very slow walking.

Methods: Ten healthy individuals underwent an experimental protocol whereby a set of perturbations directed inward (medially to a stance leg) and outward (laterally to a stance leg) of three intensities ( = 5%, = 10%, and = 15% of body weight), applied at three instances of a stance phase, were delivered in random order to the pelvis using a balance assessment robot while walking on a treadmill at three walking speeds ( = 0.

Comparison of Convolutive Kernel Compensation and Non-Negative Matrix Factorization of Surface Electromyograms.

We compared non-negative matrix factorization (NMF) and convolution kernel compensation techniques for high-density electromyogram decomposition. The experimental data were recorded from nine healthy persons during controlled single degree of freedom (DOF) wrist flexion-extension, supination-pronation, and ulnar-radial deviation movements. We assembled the identified motor units and NMF components into three groups.

Feasibility of robot-based perturbed-balance training during treadmill walking in a high-functioning chronic stroke subject: a case-control study.

Background: For stroke survivors, balance deficits that persist after the completion of the rehabilitation process lead to a significant risk of falls. We have recently developed a balance-assessment robot (BAR-TM) that enables assessment of balancing abilities during walking. The purpose of this study was to test feasibility of using the BAR-TM in an experimental perturbed-balance training program with a selected high-functioning stroke survivor.

The effect of haptic interaction between balance assessment robot and pelvis on muscle activation of leg muscles.

Admittance control is considered as a promising paradigm in rehabilitation that provides us with means to establish well controlled and adjustable interaction and cooperation between rehabilitation devices and patients. Recently we developed balance assessment robot (BAR) for studying postural responses during walking as well as for pelvis manipulation during walking that implements admittance control as a mean of interaction with user. In this study we evaluated the characteristics of transparent haptic interaction and investigated whether transparent haptic interaction induces adaptations in muscle activation patterns with respect to free walking.

A novel robot-assisted training approach for improving gait symmetry after stroke.

Gait asymmetry as a consequence of hemiparesis is known as a serious long-term disability, where typical compensatory gait movements are used by stroke subjects in order to cope with their daily activities. This study presents a gait symmetry training approach consisting of the adaptive robot assistance with the combination of the visual feedback integrated in Balance Assessment Robot for treadmill walking (BAR-TM). The support algorithm is based on gait temporal parameters that change the level of assistive support, which was triggered at different gait subphase events.

Robot-supported assessment of balance in standing and walking.

Clinically useful and efficient assessment of balance during standing and walking is especially challenging in patients with neurological disorders. However, rehabilitation robots could facilitate assessment procedures and improve their clinical value. We present a short overview of balance assessment in clinical practice and in posturography.

An effective balancing response to lateral perturbations at pelvis level during slow walking requires control in all three planes of motion.

In this study we investigated balancing responses to lateral perturbations during slow walking (0.85m/s). A group of seven healthy individuals walked on an instrumented treadmill while being perturbed at the level of waist at left heel strike in outward and inward lateral directions.

The comparison of stepping responses following perturbations applied to pelvis during overground and treadmill walking.

Background: Treadmills are used frequently in rehabilitation enabling neurologically impaired subjects to train walking while being assisted by therapists. Numerous studies compared walking on treadmill and overground for unperturbed but not also perturbed conditions.

Objective: The objective of this study was to compare stepping responses (step length, step width and step time) during overground and treadmill walking in a group of healthy subjects where balance assessment robots applied perturbing pushes to the subject's pelvis in sagittal and frontal planes.

Overground gait training using a motorized assistive device in patients with severe disabilities after stroke.

Regaining of the patient's ability to walk after stroke is an important goal of rehabilitation programmes. The ultimate goal of gait rehabilitation is to empower patients for overground walking. We have previously developed a prototype of a therapist-controlled mobile platform with compliant pelvis support mechanism that enables balance training during overground walking (device E-go).

A novel robot for imposing perturbations during overground walking: mechanism, control and normative stepping responses.

Background: The most common approach to studying dynamic balance during walking is by applying perturbations. Previous studies that investigated dynamic balance responses predominantly focused on applying perturbations in frontal plane while walking on treadmill. The goal of our work was to develop balance assessment robot (BAR) that can be used during overground walking and to assess normative balance responses to perturbations in transversal plane in a group of neurologically healthy individuals.