Extreme Sleepiness: Quantification of EOG and Spectral EEG Parameters

Abstract

Our earlier research has shown considerable increases of and intercorrelations between subjective sleepiness, alpha, theta, and delta power density of the EEG as well as slow rolling eye movements (SEM) during night-time, monotonous work tasks. The purpose of the present methodological study was to establish EEG-EOG criteria for extreme behavioral sleepiness. Medilog tape-recorders were used to record EEG and EOG on 5 males and 5 females during a 45 min visual vigilance test. Performance on the test was also recorded on the tape as well as experimenter-scored dozing off episodes (from TV supervision). The EEG was subjected to computerized spectral analysis in 7.5 s epochs, and the EOG was scored visually for slow eye movements in the same epochs. The epochs immediately preceding a hit, miss and dozing off differed significantly. There was most power density in the alpha, theta and delta bands and most SEM activity before dozing off episodes and least before hits. The power density and the SEM activity were significantly increased one whole minute before dozing off events and missed signals compared to hits. Just prior to the ultimate sleepiness, i.e., the dozing off, the SEM activity and the delta and theta power density were further increased, while alpha power density was at its maximum during the last three epochs before the dozing off. The response patterns of all subjects were rather homogeneous. In conclusion, behavioral sleepiness is systematically reflected in spectral EEG and EOG parameters and the results support attempts to use these variables to indicate sleepiness in active subjects in real life situations.

Vigilance, alertness, or sustained attention: physiological basis and measurement

“…These features are also seen with sleep deprivation. During and following sleep deprivation there is a progressive increase in absolute power and in relative theta and delta power in the EEG background, accompanied by an increase in slow eye movements, and correlated with subjective sleepiness (Caldwell, 2002;Cajochen et al, 1995;Lorenzo, 1995;Smith, 2002;Torsvall and Akerstedt, 1988b). This EEG slowing gradually increases until the sleep deprived subject dozes off (Torsvall and Akerstedt, 1988b).…”

Effects of marijuana on neurophysiological signals of working and episodic memory

“…Before each interval, blood pressure and pulse were recorded with a wrist blood pressure monitor, and subjects documented their subjective feelings on a 16-question visual analog scale and the Karolinska sleepiness scale (Torsvall and Åkerstedt 1988).…”

Lapses in alertness: Brain-evoked responses to task-irrelevant auditory probes.

“…Belyavin and Wright (1987) reported that changes in amplitudes in theta (4-7 Hz) and beta (14-21 Hz) EEG bands could be used to predict changes in performance on a simple vigilance task, while delta (1-3 Hz) and beta band levels were best predictors of fluctuations in performance on a more difficult discrimination task. Torsvall and Akerstedt (1988) observed that slow eye movements and a large increase in alpha EEG precede dozing off during performance of a simple behavioral task. Ogilvie, Simons, Kuderian, MacDonald, and Rustenburg (1991), using an auditory response task at the beginning of all-night sleep sessions, have recently claimed that power in all EEG bands increases when sleep-related lapses first occur.…”