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Download Blink behaviour based drowsiness detection
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Vigilance score 0 1 2 3 4 EEG content Background of continuous beta waves, no alpha, no theta waves Occurrence of alpha and/or theta waves, in at least two regions of the brain, for less than a cumulative length of 5 second Occurrence of alpha and/or theta waves, in at least two regions of the brain, for less than a cumulative length of 5 second or occurrence of alpha and/or theta waves, in at least two regions of the brain, for more than a cumulative length of 5 second Occurrence of alpha and/or theta waves, in at least two regions of the brain, for more than a cumulative length of 5 second Continuous alpha and/or theta waves Blinks and eye movements Normal blinks and eye movements Normal blinks and eye movements and slow blink (s) or eye movement (s) and normal blinks and eye movements and slow blink (s) or eye movement (s) Slow blinks and eye movements Table 5.1: Objective Sleepiness Scoring (OSS) derived from EEG and blink data (Muzet, 2002). The EEG data is examined either visually or by spectral analysis to detect occurrence of theta, alpha or beta activity. When performing spectral analysis the absolute power values for the different frequency bands are given. Occurrence of low frequencies (< 4 Hz) in the awake EEG is probably due to artefacts and will not be classified as delta activity, as delta activity only occurs during sleep. The regions of the brain are the occipital, temporal, parietal, frontal and central region. To eliminate cases where only localized EEG patterns arise, the activity shall be found in at least two regions of the brain (Muzet, 2002). 18
