Use of Imaginary Lower Limb Movements to Control Brain–Computer Interface Systems

Abstract

This review addresses the challenge of using brain–computer interface (BCI) systems controlled by imagining lower limb movements and their use in clinical practice. There are significantly fewer studies in this area than of BCI controlled by imaginary arm movements, partly because of methodological difficulties. This review describes various modifications to BCI, most studies being directed to restoring walking function and fewer to restoring movements at the ankle joint. Restoration of locomotor function by controlling a BCI by imaginary walking to move an avatar in a virtual space is quite often used. In a number of studies, imaginary movements are accompanied by functional electrical stimulation activating the muscles carrying out the imaginary movements or triggering movements of mechanical devices (orthoses, exoskeletons). Finally, fundamentally new integrative approaches are described, such as BCI controlled by imaginary arm movements generating signals triggering movements of the avatar’s leg or an orthosis, with tactile stimulation of the forearm with the stepping rhythm. The literature contains no studies on the challenge of restoring lower limb functions in Russia.