A preliminary quantitative EEG study on Augmented Reality Guidance of Manual Tasks

Augmented reality (AR) head mounted displays (HMDs) combine user's natural view of the real world with virtual data. Thus, they might be particularly suited to guide manual tasks as in computer-aided-surgery. However, the typical focal plane of commercial devices is outside the user's peripersonal space (i.e. the space containing reachable objects), limiting the performance of manual-task guidance. Specifically, known issues such as the "vergence-accomodation-conflict" and the "focus-rivalry" may lead to visual fatigue and mental workload worsening task performance. Here, we exploit EEG recordings during a "connecting-the-dots" task performed with and without AR to study the effects of mental workload associated with AR-related visual fatigue. First, we quantify the reduction of users' performance based on starting and end points gap errors. Then, we investigate the effects on AR usage on cortical activity through the analysis of EEG power and Frontal Alpha Asymmetry (FAA) index. Although preliminary, EEG power results suggest that mental workload associated with AR usage may derive from enhanced difficulty associated with the task.