A brain-computer interface (BCI) is a hardware and software communications system that permits cerebral activity alone to control computers or external devices. The immediate goal of BCI research is to provide communications capabilities to severely disabled people who are totally paralyzed or 'locked in' by neurological neuromuscular disorders, such as amyotrophic lateral sclerosis, brain stem stroke, or spinal cord injury. Here, we review the state-of-the-art of BCIs, looking at the different steps that form a standard BCI: signal acquisition, preprocessing or signal enhancement, feature extraction, classification and the control interface. We discuss their advantages, drawbacks, and latest advances, and we survey the numerous technologies reported in the scientific literature to design each step of a BCI. First, the review examines the neuroimaging modalities used in the signal acquisition step, each of which monitors a different functional brain activity such as electrical, magnetic or metabolic activity. Second, the review discusses different electrophysiological control signals that determine user intentions, which can be detected in brain activity. Third, the review includes some techniques used in the signal enhancement step to deal with the artifacts in the control signals and improve the performance. Fourth, the review studies some mathematic algorithms used in the feature extraction and classification steps which translate the information in the control signals into commands that operate a computer or other device. Finally, the review provides an overview of various BCI applications that control a range of devices.

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Brain Computer Interfaces, a Review

Objective. The aim of the study was to present a systematic review of studies that investigate the effects of robot-assisted therapy on motor and functional recovery in patients with stroke. Method...

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Effects of Robot-Assisted Therapy on Upper Limb Recovery After Stroke: A Systematic Review

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

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

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.

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Treadmill training of paraplegic patients using a robotic orthosis

In contrast to peripheral nerves, central axons do not regenerate. Partial injuries to the spinal cord, however, are followed by functional recovery. We investigated the anatomical basis of this recovery and found that after incomplete spinal cord injury in rats, transected hindlimb corticospinal tract (CST) axons sprouted into the cervical gray matter to contact short and long propriospinal neurons (PSNs). Over 12 weeks, contacts with long PSNs that bridged the lesion were maintained, whereas contacts with short PSNs that did not bridge the lesion were lost. In turn, long PSNs arborize on lumbar motor neurons, creating a new intraspinal circuit relaying cortical input to its original spinal targets. We confirmed the functionality of this circuit by electrophysiological and behavioral testing before and after CST re-lesion. Retrograde transynaptic tracing confirmed its integrity, and revealed changes of cortical representation. Hence, after incomplete spinal cord injury, spontaneous extensive remodeling occurs, based on axonal sprout formation and removal. Such remodeling may be crucial for rehabilitation in humans.

The injured spinal cord spontaneously forms a new intraspinal circuit in adult rats.

Task-oriented repetitive movements can improve muscular strength and movement coordination in patients with impairments due to neurological or orthopedic lesions. The application of robotics and automation technology can serve to assist, enhance, evaluate, and document neurological and orthopedic rehabilitation of the lower and upper extremities. This review presentation will give an overview of patient-cooperative techniques to the robot-aided gait rehabilitation of paralyzed patients. Patient-cooperative means that the technical system considers the patient intention and efforts rather than imposing any predefined movement or inflexible strategy. It is hypothesized that cooperative approaches have the potential to improve the therapeutic outcome compared to classical rehabilitation strategies. Three new cooperative strategies are presented in this review. In all three strategies the patient's movement effort is detected and processed in three different ways. First, the data is used to offer the patient an increased freedom of movement by a certain amount of robot compliance. Second, the robot behavior is adapted to the patient movement efforts. In the third strategy the recorded movement data are displayed to the patient in order to improve the patient efforts by biofeedback principles.

Cooperative strategies for robot-aided gait neuro-rehabilitation

While robotic rehabilitation devices are gaining popularity in research and clinical use, a possible drawback of these devices is the reduced physical interaction between the therapist and the patient compared to manual training. To compensate for this lack, the device has to assess the patient's movements and provide (bio-)feedback to the patient. Furthermore, it could deliver instructions and increase motivation. The design and implementation of an immersive virtual environment for robot-assisted gait training are described that delivers feedback and increases motivation. Subjects can navigate through exchangeable virtual environments by modulating their performance of the left and right leg. Preliminary tests show usability with control subjects. Clinical tests are still required to show applicability in the clinical routine and to test for therapeutic efficacy.

Combining Immersive Virtual Environments with Robot-Aided Gait Training

Abstract Aufgabenorientierte, repetitive Bewegungen können die motorische Erholung bei Patienten mit inkompletter Querschnittlähmung, Halbseitenlähmung oder orthopädischen Verletzungen verbessern. Dieser Artikel stellt die Technik des neuen Therapieroboters ARMin vor. ARMin unterstützt das Training von funktionellen Bewegungen und Aktivitäten des täglichen Lebens der oberen Extremitäten.

ARMin – Roboter für die Bewegungstherapie der oberen Extremitäten (ARMin – Robot for Movement Therapy of the Upper Extremities)

of EP1586291A device for adjusting the height of and relief force acting on a weight is especially provided to be used for walking therapy of paraparetic or hemiparetic patients within a locomotion training means. Said weight of the patient is supported by a cable (11, 30). A first cable length adjustment means (1) provides an adjustment of the length of the cable (11) to define the height of said suspended weight. A second cable length adjustment means (2) provides an adjustment of the length of the cable (11) to define the relief force acting on the suspended weight. This allows a quick and reliable determination and adjustment of the height for different patients and of the relief force within the training program of every patient.

Device for adjusting the height of and the relief force acting on a weight

A device for adjusting the height of and relief force acting on a weight is especially provided to be used for walking therapy of paraparetic or hemiparetic patients within a locomotion training means. Said weight of the patient is supported by a cable. A first cable length adjustment means provides an adjustment of the length of the cable to define the height of said suspended weight. A second cable length adjustment means provides an adjustment of the length of the cable to define the relief force acting on the suspended weight. This allows a quick and reliable determination and adjustment of the height for different patients and of the relief force within the training program of every patient.

Gery Colombo

Papers

Cooperative strategies for robot-aided gait neuro-rehabilitation

Combining Immersive Virtual Environments with Robot-Aided Gait Training

ARMin – Roboter für die Bewegungstherapie der oberen Extremitäten (ARMin – Robot for Movement Therapy of the Upper Extremities)

Device for adjusting the height of and the relief force acting on a weight

Device and process for adjusting the height of and the relief force acting on a weight