Controlling a Tactile ERP-BCI in a Dual-Task

When using Brain Computer Interfaces (BCIs) to control a game, the BCI may have to compete with gaming tasks for the same perceptual and cognitive resources. We investigated (1) if and to what extent event related potentials (ERPs) and ERP-BCI performance are affected in a dual-task situation, and (2) if these effects are a function of the level of difficulty of a concurrent task. Ten participants performed an ERP-BCI task that involved attending to a target location in sequences of tactile stimuli. The ERP-BCI task was performed either in isolation or secondary to a visual n-back task with two levels of difficulty. We observed (1) a decreased P300 and BCI bitrates, and an increased level of subjective mental effort for both dual-task conditions compared to the BCI-only condition. The decreased classification accuracies were still well above chance, but arguably too low for effective BCI control. Furthermore, (2) we did not find an effect of task difficulty on the P300, bitrates, and subjective mental effort. We discuss reallocation of attention caused by a concurrent task, but unaffected by task difficulty, and the role of task priority. Concluding, control of a tactile ERP-BCI in a dualtask situation is feasible, but performance is degraded.