Multimodal target detection using single trial evoked EEG responses in single and dual-tasks.

The detection of event-related potentials in the electroencephalogram signal is a common way for creating a brain-computer interface (BCI). Successful detection of evoked responses can be enhanced by the user selectively attending to specific stimuli presented in the BCI task. Because BCI users need a system that performs well in a variety of contexts, even ones that may impair selective attention, it is critical to understand how single trial detection is affected by attention. We tested 16 participants using a rapid serial visual/auditory presentation paradigm under three conditions, one in which they detected the presence of a visual target, one in which they detected the presence of an auditory target, and one in which they detected both visual and auditory targets. The behavioral performance indicates that the visual task was more difficult than the auditory task. Consistent with the higher behavioral difficulty of the visual task, single trial performance showed no difference between single and dual-task for the visual target detection (mean=0.76). However, the area under the curve for the auditory target detection was significantly lower than the dual-task (mean=0.81 for single task, 0.75 for dual-task). The results support the conclusion that single-trial target detection is impaired when attention is divided between multiple tasks.