EEG, Consciousness, and Sleep

During an 8-hour sleep period, 21 normal, male, alpha-dominant adults were presented with information via tape recorder. Whether subjects heard and later recalled the information correlated with their EEG patterns. The probability of remembering and responding to meaningful auditory stimulation increased as waking alpha activity increased near the stimulation. Absence of alpha did not indicate unconsciousness, but presence of delta did, with unconsciousness directly related to delta amplitude and inversely related to delta frequency. Several seconds of EEG scored by eye reliably measured consciousness state. Awakening from sleep due to auditory stimulation could produce patterns along a consciousness continuum based on alpha and delta amounts.

Study at a glance

Abstract

Monopolar occipital and vertex EEGs were taken from 21 normal, male, alpha-dominant adults during an 8-hour sleep. Information was presented by means of a tape recorder during this period. Subjects reported if they heard the information during stimulation and were later tested, upon rising, to see if they could recall it. These two variables were correlated with electroencephalographic patterns occurring during the information presentation. The following conclusions were drawn: (1) the probability of remembering and responding to meaningful auditory stimulation increased as the quantity and quality of waking alpha within the immediate vicinity increased; (2) the absence of alpha does not mean unconsciousness; (3) the presence of delta is an indication of unconciousness; unconciousness is directly related to delta amplitude and inversely related to delta frequency; (4) Several seconds of EEG scored by eye is a reliable measure of the state of conciousness; and (5) Awakening from sleep or the borderline of sleep as a result of auditory stimulation may lead to patterns showing special stimulus effects which fall along a consciousness continuum relative to the amount of alpha and delta within a pattern.