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 an area 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 bit rate, 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; and 2) we did not find an effect of task difficulty on the P300, bit rates, 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 dual-task situation is feasible, but performance is degraded.