Effect of Transcranial Direct Current Stimulation on an Individual’s Ability to Learn to Control a Brain-Computer Interface

Purpose: Brain-computer interfaces (BCI) are systems which enable direct communication between a brain and an external device by translating electrical brain activity into meaningful output. This technology can be used by individuals with motor impairments to interact and communicate with their external environment. BCIs based upon manipulating the sensorimotor rhythm (SMR) through motor imagery have lengthy learning periods, which present a significant barrier to using this technology. We hypothesize that this learning period will be significantly reduced by transcranial direct current stimulation (tDCS), which temporarily augments cortical excitability.Methods: Participants were assigned into two groups - the experimental group, which received tDCS, and a control group, which received sham stimulation. Following tDCS, the participants used a SMR-based BCI to move a falling ball to hit targets that appeared on the left or right side of screen. The effect of tDCS was assessed by comparing the overall task accuracy and the SMR change during motor imagery between the two groups .Results: The experimental group was significantly more accurate in controlling the BCI than the control group (p = 0.021); however, there was no significant difference between groups in the SMR change upon motor imagery (p = 0.22). Conclusions. tDCS can be used to improve the performance of healthy individuals learning to use an SMR-based BCI.