Imre Cikajlo

Universal Haptic Drive: A Robot for Arm and Wrist Rehabilitation

In this paper we present a universal haptic drive (UHD), a device that enables rehabilitation of either arm (“ARM” mode) or wrist (“WRIST” mode) movement in two degrees-of-freedom. The mode of training depends on the selected mechanical configuration, which depends on locking/unlocking of a passive universal joint. Actuation of the device is accomplished by utilizing a series elastic actuation principle, which enables use of off-the-shelf mechanical and actuation components. A proportional force control scheme, needed for implementation of impedance control based movement training, was implemented. The device performance in terms of achievable lower and upper bound of viable impedance range was evaluated through adequately chosen sinusoidal movement in eight directions of a planar movement for the “ARM” mode and in eight directions of a combined wrist flexion/extension and forearm pronation/supination movement for the “WRIST” mode. Additionally, suitability of the universal haptic drive for movement training was tested in a series of training sessions conducted with a chronic stroke subject. The results have shown that reliable and repeatable performance can be achieved in both modes of operation for all tested directions.

Telerehabilitation using virtual reality task can improve balance in patients with stroke

Purpose: The objective of the telerehabilitation is a continuation of the rehabilitation process on patients’ home. The study also compares the balance training in clinical environment with the telerehabilitation approach when the physiotherapists and physicians can follow the progress remotely. Method: In this paper, the preliminary study of the pilot project with virtual reality (VR)-based tasks for dynamic standing frame supported balance training is presented. Six patients with stroke participated in the study. The patients performed the balance training 3 weeks, 2 weeks in the clinical settings and 1 week in the home environment, five times a week, and each time for up to 20 minutes. Objective effectiveness was demonstrated by parameters as track time, number of collisions and the clinical instruments Berg Balance Scale (BBS), Timed Up & Go (TUG), 10-m walk test and standing on the unaffected and affected extremity. The outcomes were compared to the balance training group without VR and telerehabilitation support. A 2-way ANOVA was used to explore the differences between the both stroke groups. Results: In patients who were subject to VR supported balance training, the BBS demonstrated improvement for 15%, the TUG for 29%, the 10-m walk for 26%, stance time on the affected and unaffected extremity for 200 and 67%, respectively. The follow-up demonstrated that the patients preserved the gained functional improvement. The VR task performance time and number of collisions decreased to 45 and 68%, respectively. Besides, no statistical differences were found between the telerehabilitation approach with VR supported balance training and conventional balance training in clinical settings either regarding the overall mean level or regarding the mean improvement. Conclusions: The telerehabilitation approach in VR supported balance training improved balance in stroke patients and had similar effect on patients’ postural functional improvement as conventional balance training in clinical settings. However, when balance training is continued on patient’s home instead of the hospital, it would eventually decrease the number of outpatients’ visits, reduce related costs and enable treatment of larger number of patients. Implications for Rehabilitation People suffering from stroke have severe problems with posture and balance. This study demonstrates that using target based tasks in a virtual environment can improve balance in stroke population. Telerehabilitation offers continuation of balance training in the remote centres or at home. The longer rehabilitation period improves functionality and therefore the quality of life.

Directionally Specific Objective Postural Response Assessment Tool for Treatment Evaluation in Stroke Patients

The aim of the research is to develop an objective evaluation tool for use in stroke rehabilitation clinical practice. Stroke patients are prone to particularly high risk of fall, which may differ for various directions of movement. An apparatus enabling perturbations and postural response assessment in eight directions in transversal plane during standing was used to assess data in seven neurologically intact volunteers and 10 stroke patients before and after the rehabilitation. Ground reaction force and center of pressure were acquired during the perturbation, signal processed and compared to Berg Balance Scale (BBS), a clinical outcome measure of balance. The results of the weight load ratio between the affected and unaffected lower extremity demonstrated objective positive outcomes of the rehabilitation and also correlated with the clinical instrument BBS. Additionally, the center of pressure ratio between the anterior/posterior and medial/lateral peak for each perturbation direction have shown identifiable postural response strategies in selected directions of transverse plane. The directional postural information can be helpful when identifying and evaluating the objective rehabilitation progress which can lead to application of targeted rehabilitation techniques. The directional indicator also demonstrated correlation with the BBS in directions indicating rehabilitation progress. When considering the common use with the clinical instrument, the proposed objective rehabilitation progress evaluation tool may also become helpful in directional fall risk indication. The proposed tool may become a powerful instrument, when the balance training and postural response assessment will move to remote or home environment as a telerehabilitation service.

Variable structure pantograph mechanism with spring suspension system for comprehensive upper-limb haptic movement training.

Numerous haptic devices have been developed for upper-limb neurorehabilitation, but their widespread use has been largely impeded because of complexity and cost. Here, we describe a variable structure pantograph mechanism combined with a spring suspension system that produces a versatile rehabilitation robot, called Universal Haptic Pantograph, for movement training of the shoulder, elbow, and wrist. The variable structure is a 5-degree-of-freedom (DOF) mechanism composed of 7 joints, 11 joint axes, and 3 configurable joint locks that reduce the number of system DOFs to between 0 and 3. The resulting device has eight operational modes: Arm, Wrist, ISO (isometric) 1, ISO 2, Reach, Lift 1, Lift 2, and Steer. The combination of available work spaces (reachable areas) shows a high suitability for movement training of most upper-limb activities of daily living. The mechanism, driven by series elastic actuators, performs similarly in all operational modes, with a single control scheme and set of gains. Thus, a single device with minimal setup changes can be used to treat a variety of upper-limb impairments that commonly afflict veterans with stroke, traumatic brain injury, or other direct trauma to the arm. With appropriately selected design parameters, the developed multimode haptic device significantly reduces the costs of robotic hardware for full-arm rehabilitation while performing similarly to that of single-mode haptic devices. We conducted case studies with three patients with stroke who underwent clinical training using the developed mechanism in Arm, Wrist, and/or Reach operational modes. We assessed outcomes using Fugl-Meyer Motor Assessment and Wolf Motor Function Test scores showing that upper-limb ability improved significantly following training sessions.

DEVELOPMENT OF A GAIT RE-EDUCATION SYSTEM IN INCOMPLETE SPINAL CORD INJURY

OBJECTIVE The aim of the paper is to present the development of a system for swing phase restoration in patients with incomplete spinal cord injury. METHODS The functional electrical stimulation based gait re-education system comprises a sensory system, a system providing cognitive feedback and a motor augmentation system facilitating and correcting the movement of the swinging extremity. Mathematical algorithms estimate swing quality and classify the swing phase of walking into 3 levels, termed cognitive feedback, which is provided to the patient as an auditory signal. A single-channel peroneal functional electrical stimulation was applied as a motor augmentation system to provide the patient with the motor assistance required. The important novelty of the proposed system is that motor assistance is provided only at the level that enables the patient to perform a good swing. RESULTS The developed system was tested in a patient with incomplete spinal cord injury, with C4-5 lesion, whilst walking on a treadmill. The results show that the automated sensory-driven functional electrical stimulation augmentation system, providing only the minimal assistance required based on the subjects performance, is a viable approach that successfully releases a therapist from the task of delivering properly timed stimulation of adequate intensity in assisting the swing phase of walking.

FES Rehabilitative Systems for Re-Education of Walking in Incomplete Spinal Cord Injured Persons.

Objective. The aim of the paper is to present various relatively simple functional electrical stimulation (FES) systems that affect neural circuits and reflex behavior by providing necessary peripheral input to the lower extremities of incomplete spinal cord injured (SCI) persons.

Haptic floor for virtual balance training

Replacing the traditional balance training task with tasks in virtual environment in subjects after stroke was a step toward independent rehabilitation. The virtual reality supported balance training relieved the physiotherapist from strenuous work, besides, also enabled rehabilitation treatment on individuals home and functional balance ability assessment. However, adding a haptic floor to the virtual reality balance training enhanced the approach to the postural response training and assessment. We have developed a two degrees of freedom, position controlled, haptic floor plates providing postural perturbations according to the collisions with obstacles in the virtual environment. The subject generated a postural response to stabilize the body during balance training. Such task represents for the subject with stroke a serious challenge. However, the standing frame prevented the possibility to fall. The virtual reality supported balance training with haptic floor was so far carried out in healthy individuals and tested in single subject after stroke. A basic response characteristic of haptic floor was examined. The preliminary results demonstrated a sufficient dynamics of the haptic floor and great acceptability among the participating subjects. Thus the additional haptic feedback in goal based balance training may contribute to the improvement of subjects functional balance and postural abilities and so increase the quality of life. However, to confirm the clinical applicability of the haptic floor in balance training and evaluation of postural responses, a further study including clinical tests within a larger group of stroke population should be carried out.

Virtual reality task for telerehabilitation dynamic balance training in stroke subjects

The paper presents a virtual reality based dynamic balance training. The telerehabilitation balance training in stroke subject took place in smarthome, simulating a home environment. Virtual environment was designed as a game in web-explorer enabling the medical professionals to remotely supervise and control the balance training. In preliminary testing a right-side hemiparetic subject participated and demonstrated high motivation, high level of learning and accomplished the therapy with promising clinical outcomes. The subject performed the therapy five times a week, each time for 17 to 20 minutes for four weeks. The results were evaluated by objective game parameter as track time, number of hits and clinical instruments Berg Balance Scale, Timed Up&Go and 10m Walk tests. The outcomes indicate similar progress to those obtained in the clinical environment.

Design and Test of a Novel Closed-Loop System That Exploits the Nociceptive Withdrawal Reflex for Swing-Phase Support of the Hemiparetic Gait

A novel closed-loop system for improving gait in hemiparetic patients by supporting the production of the swing phase using electrical stimulations evoking the nociceptive withdrawal reflex was designed. The system exploits the modular organization of the nociceptive withdrawal reflex and its stimulation site- and gait-phase modulation in order to evoke movements of the hip, knee, and ankle joints during the swing phase. A modified model reference adaptive controller (MRAC) was designed to select the best stimulation parameters from a set of 12 combinations of four electrode locations on the sole of the foot and three different stimulation onset times between heel-off and toe-off. It was hypothesized that the MRAC system would result in a better walking pattern compared with an open-loop preprogrammed fixed pattern of stimulation (FPS) controller. Thirteen chronic or subacute hemiparetic subjects participated in a study to compare the performance of the two control schemes. Both control schemes resulted in a more functional gait compared to no stimulation (P <; 0.05) with a weighted joint angle peak change of 4.0 ± 1.6 (mean ± Standard deviation) degrees and 3.1 ± 1.4 degrees for the MRAC and FPS schemes, respectively. This indicates that the MRAC scheme performed better than the FPS scheme (P <; 0.001) in terms of reaching the control target.

FES Gait Re-education: The Swing Phase Estimation

This paper presents the use of multiple sensors for walking assessment and provision of cognitive feedback during early re‐education of incomplete spinal cord injured (SCI) humans. The paper is focused on the swing phase estimation as an important part of the Functional Electrical Stimulation (FES) gait re‐education system for incomplete spinal cord injured persons. The proposed sensory system comprises four accelerometers, one gyro placed at the shank of the paretic leg, and two goniometers placed at the knee and ankle joints, respectively. The data from the sensors are input in the mathematical algorithm applied for swing quality estimation. The output from the algorithm is a numerical value. The calculated output is divided into three levels, each defining the swing quality in terms of good, sufficient, and poor. This information is provided to the patient as an auditory signal. The patient is taught to maximize his efforts to improve the quality of walking, that is, to move the more affected leg in a way that will generate the auditory output corresponding to the level “good”.