A Prototype Real-Time System for Assessing Vigilance Levels and for Alerting the Subject with Sound Stimulation

A Prototype Real-Time System for Assessing Vigilance Levels and for Alerting the Subject with Sound Stimulation

  This paper presents a prototype real-time system that assesses the vigilance level of a subject and alerts the subject with sound stimulation when the assessed vigilance level is below a predetermined threshold. An acceleration property of saccadic eye movement, which is measured with a limbus eye tracker, is used as an index of the vigilance level. The algorithms for computing the index and for triggering sound stimulation according to the index value were implemented in a digital signal processor for realizing a real-time system. The developed system was evaluated through eye tracking tasks. The results indicated that the developed system stably assessed the vigilance level and stimulated the subject as designed when necessary. Although more precise and wide investigation is necessary to make a conclusion, we could confirm quantitatively that the system was able to arouse the subject by using sound stimulation. These results indicate a feasibility of the developed system not only for vigilance monitoring and subject stimulating, but also for exploring quantitatively effective conditions of stimulation to arouse the subject.