Movement Anticipation and EEG: Implications for BCI-Contingent Robot Therapy

Abstract

Brain-computer interfacing is a technology that has the potential to improve patient engagement in robot-assisted rehabilitation therapy. For example, movement intention reduces mu (8-13 Hz) oscillation amplitude over the sensorimotor cortex, a phenomenon referred to as event-related desynchronization (ERD). In an ERD-contingent assistance paradigm, initial BCI-enhanced robotic therapy studies have used ERD to provide robotic assistance for movement. Here we investigated how ERD changed as a function of audio-visual stimuli, overt movement from the participant, and robotic assistance. Twelve unimpaired subjects played a computer game designed for rehabilitation therapy with their fingers using the FINGER robotic exoskeleton. In the game, the participant and robot matched movement timing to audio-visual stimuli in the form of notes approaching a target on the screen set to the consistent beat of popular music. The audio-visual stimulation of the game alone did not cause ERD, before or after training. In contrast, overt movement by the subject caused ERD, whether or not the robot assisted the finger movement. Notably, ERD was also present when the subjects remained passive and the robot moved their fingers to play the game. This ERD occurred in anticipation of the passive finger movement with similar onset timing as for the overt movement conditions. These results demonstrate that ERD can be contingent on expectation of robotic assistance; that is, the brain generates an anticipatory ERD in expectation of a robot-imposed but predictable movement. This is a caveat that should be considered in designing BCIs for enhancing patient effort in roboticallyassisted therapy.

Spatial-Frequency Feature Learning and Classification of Motor Imagery EEG Based on Deep Convolution Neural Network

“…Via MI-based BCI system, users can control robots or external machines merely by movement imagination, without the intervention of peripheral nerve. Due to its great potential application value in motor function rehabilitation [8], motor function assistance, and so forth, MI-based BCI system has been widely concerned.…”

Experimental Study on Upper-Limb Rehabilitation Training of Stroke Patients Based on Adaptive Task Level: A Preliminary Study

“…How to stimulate the enthusiasm of the subject to the greatest extent is one of the main considered issues throughout the design of the rehabilitation system. Many training or controlling strategies have been adopted to improve training motivation, such as varied training tasks, vivid visual feedback or virtual reality, friendly interaction, and intelligent control methods [21–23]. However, the training task is usually appointed in advance during the robot-aided motion exercise.…”

Volition-adaptive control for gait training using wearable exoskeleton: preliminary tests with incomplete spinal cord injury individuals

“…These BMI based systems have proved to improve the motor cortex ability of physically impaired patients while being trained for a long-term [ 68 – 70 ]. In the present study, the BMI system is used as a volitional order to trigger the gait movement, ensuring the user involvement in therapy and to train the motor cortex [ 71 ]. It allowed processing the brain activity of the subjects in order to detect when they wanted to move, and start accordingly the movement of the exoskeleton.…”