Detection of Foot Motor Imagery Using the Coefficient of Determination for Neurorehabilitation Based on BCI Technology

A motor imagery based brain-computer interface (BCI) translates the subject's motor imagination of a body part into a control signal through real-time detection of particular features in the electroencephalography (EEG) signal. This type of BCIs might restore motor function by inducing brain plasticity to restore normal brain function. The purpose of this study was to investigate the feasibility of using the coefficient of determination (r(2)) as an estimator of event-related desynchronization (ERD) during foot motor imagery, in order to design a neurorehabilitation tool based on motor imagery BCI. 8-channels of EEG were recorded from three healthy subjects for different tasks: actual and imagined movement of both feet, imagined movement of left/right foot. The coefficient was computed for each situation, and its spatial distribution for a determined frequency value was represented in topography maps. The results showed that the r(2) is a reliable indicator of ERD related to foot motor imagery for all subjects. These findings suggest that in near future the design of a neurorehabilitation tool based on foot motor imagery using this coefficient is possible.