Fz theta divided by Pz alpha as an index of task load during a PC-based air traffic control simulation

In this investigation 21 students were trained to perform a highly simplified PCbased air traffic control (ATC) approach sequencing task simultaneously with a secondary (auditory) oddball task. Task load was manipulated by varying the number of aircraft on screen. Besides task load, time-on-task effects were investigated by monitoring the ATC task performance during two hours. The effects of the manipulations were assessed using subjective (RSME), performance and physiological (EEG spectral power, ERP P300) measures. An index based on EEG spectral power in alpha and theta ranges was calculated by dividing the power of the Fz theta band by the power of the Pz alpha band. The index was tested with regard to its sensitivity for task load and time-on-task effects. The results provide support for Fz theta divided by Pz alpha as an index of task load.