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...

/pdf/effects-of-robot-assisted-therapy-on-upper-limb-recovery-1qb9tf8d78.pdf

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.

Movement analysis with the driven gait orthosis Lokomat

Locomotor activity in spinal man

Ein System fur die Armtherapie verfugt uber mehrere Antriebe. Ein erster Antrieb (11) und ein zweite Antrieb (26) legen die Position eines Oberarmrotationsmoduls (16, 17) fest, wobei mit einer Manschette (10) ein Oberarm eines Benutzers fixierbar ist. Das Oberarmrotationsmodul (16, 17) ist zweiteilig und ein dritter Rotationsantrieb (29) ist vorgesehen, um die besagte innen angeordnete (17), im geschlossenen Zustand im wesentlichen hohlzylindrische Oberarmmanschette (10) um ihre Hauptachse relativ zum ausseren Teil (16) des Oberarmrotationsmoduls (16, 17) zu drehen. Das Oberarmrotationsmodul (16, 17) ist uber ein quer drehbares Ellbogenrotationsmoduls (20, 21) mit einem ahnlich zum erstgenannten ausgestalteten Handgelenkrotationsmoduls (20, 21) verbunden. Damit ist eine interne und externe Schulter-Rotation, die Flexion bzw. Extension des Ellenbogens und die Pro/Supination des Unterarms moglich, die durch die verschiedenen Antriebe als Relativbewegung der Manschetten (8, 9 und 10) zueinander bewirkt wird.

System und verfahren für die kooperative armtherapie sowie rotationsmodul dafür

Gerät, um die Höhe eines Gewichts sowie eine auf dieses Gewicht wirkende Entlastungskraft zu regulieren

Based on observations of the locomotor capacity of spinalized cat, recent studies indicate that spinal locomotor centres can also be activated and trained in complete and incomplete paraplegic patients. Patients with incomplete paraplegia profit from the training program so that their walking ability on a stationary surface improved. This article reviews the training effects on the locomotor pattern underlying this new approach.

Gery Colombo

Papers

Movement analysis with the driven gait orthosis Lokomat

Locomotor activity in spinal man

System und verfahren für die kooperative armtherapie sowie rotationsmodul dafür

Gerät, um die Höhe eines Gewichts sowie eine auf dieses Gewicht wirkende Entlastungskraft zu regulieren

Locomotor training in paraplegic patients