A Comparison Study of Egocentric and Allocentric Visual Feedback for Motor-Imagery Brain-Computer Interfaces

Motor imagery (MI) based brain-computer interfaces (BCIs) have been studied as applications for the improving rehabilitation and recovery, as well as augmenting existing function. MI BCI systems typically provide feedback in an egocentric rather than an allocentric reference frame. This study aims to see if presenting stimuli in an allocentric reference frame is comparable to presenting egocentric stimuli. We used dynamic visual stimuli in egocentric and allocentric reference frames to induce motor imagery in a virtual reality (VR) environment. Eight participants imagined grasping actions with their left and right hands while observing egocentric or allocentric stimuli. The allocentric and egocentric reference frame tasks had comparable inter-rater agreement and precision, indicating that allocentric visual feedback is as effective as egocentric one for MI BCI.