A Study on EEG Power and Connectivity in a Virtual Reality Bimanual Rehabilitation Training System

The study of neural processes that describe bimanual activity in areas such as neurology and rehabilitation are of high interest, in particular for rehabilitation after brain injury. However, brain processes during bimanual motor rehabilitation are not fully understood during stroke rehabilitation. Hence, it is not clear how to exploit them and their possible advantages in an EEG driven Virtual Reality (VR) training. In this work, VR and EEG were combined to study the neural processes in motor areas during bimanual activity in a serious game, involving two kind of movements: Left to Right (L2R) movement (Right handle forward and Left handle backward movements) and Right to Left (R2L) movement (Right handle backward and Left handle forward movements). 10 right handed healthy people (7 Males, 3 Females, $29.9 \pm 6.21$ years old) participated in this study. As it was expected, differences between rest and bimanual activity conditions (L2R and R2L) were found, surprisingly, on lowest frequency bands, Delta and Theta. More relevant results were found on Delta band at the right Hemisphere and inter-hemispherical relations, specifically for intra-hemispherical connectivity for CPSD relations with p= 0.005 (L2R) and p= 0.02 (R2L), and power quantified with PSD with p= 0.023 (L2R) and p= 0.03 (R2L), while inter-hemispherical connectivity got lower values on resting compared to L2R movement with a p= 0.015. Besides, comparisons between resting and movement in Theta band showed significant results for inter-hemispherical connectivity (p= 0.03, L2R vs Rest, and R2L vs Rest) and differences in power for Left Hemisphere (p= 0.05). Finally, non-significant differences were found in motor cortex between the two kind of bimanual activities tested on this work. These results create an opening scenario to test for mirror effect of bimanual activities from one hemisphere to another on populations with hemi paretic conditions, aiming to apply it in a near future as therapy for Stroke Survivors.