Effects of a dual-task tracking on eye fixation related potentials (EFRP)

Abstract

The eye fixation related brain potentials (EFRP) associated with the occurrence of fixation pause can be obtained by averaging EEGs at offset of saccades. EFRP is a kind of event-related brain potential (ERP) measurable at the eye movement situation. In this experiment, EFRP were examined concurrently along with performance and subjective measures to compare the effects of tracking difficulty during a dual-task. Twelve participants were assigned four different types of a tracking task for each 5 min. The difficulty of tracking task is manipulated by the easiness to track a target with a trackball and the easiness to give a correct response to the numerical problem. The workload of the each tracking condition is different in the task quality (the difficulty of perceptual motor level and/or cognitive level). As a result, the most prominent positive component with latency of about 100 ms in EFRP was observed under all tracking conditions. The amplitude of the condition with the highest workload was smaller than that of the condition with the lowest workload, while the effects of the task quality and the correspondency with the subjective difficulty in incremental step were not recognized in this experiment. The results suggested that EFRP was an useful index of the excessive mental workload. © Springer-Verlag Berlin Heidelberg 2007.