SSVEP-Based BCI Performance and Objective Fatigue Under Different Background Conditions

In this paper the influence of different backgrounds was investigated on SSVEP-based BCI performance, with a focus on measuring objective user fatigue. We tested three different backgrounds: a black screen, white noise, and a video, with a BCI spelling application (in which four distinct frequencies were used). We measured information transfer rate (ITR), accuracy, and several parameters which could indicate user fatigue levels. The data were recorded with EEG. The level of comfort before and after the experiment, as well as the subjective level of fatigue were assessed using questionnaires, while the objective evaluation was done using the measured indexes. Eight healthy participants were tested. With the used objective fatigue evaluation method, no significant differences were found between the different background scenarios. Evaluating the study as a whole showed significantly decreased alpha-band activity (p = 0.03) at the end and a significantly increased subjective user fatigue. This experiment was conducted to investigate the level of fatigue caused by SSVEP-based BCIs in noisy environments.