“…As discussed in the drowsy driver example, monitoring real-time mental workload and vigilance is of particular importance in safety-critical environments (Lin C. T. et al, 2010 ; Khan and Hong, 2015 ; Aricò et al, 2017 ). Non-invasive BCIs that detect drops in attention level and increased mental fatigue can be utilized in a broad range of operational environments and application domains including aviation (Aricò et al, 2016 ; Hou et al, 2017 ) and industrial workspaces (Schultze-Kraft et al, 2012 ) where safety and efficiency are important, as well as educational and healthcare setups where the system can provide feedback from learners to a teacher (Ko et al, 2017 ; Spüler et al, 2017 ), evaluate sustained attention in e-learning platforms (Chen et al, 2017 ), and execute attention training for clinical patients who suffer from attention deficit hyperactivity disorder (ADHD) (Lim et al, 2019 ). It is even suggested that detection of attention level can be employed in a hybrid BCI system in which an attention classifier is integrated with other BCI algorithms in order to confirm users' focus on the BCI task and validate the produced response, thereby yielding a more reliable and robust performance (Diez et al, 2015 ).…”