Stage 4 Sleep in Schizophrenia

Abstract

THE stage 4 EEG (employing the Dement and Kleitman¹nomenclature) of sleep, as measured in our laboratory, consists of high-voltage (over 50V) slow (under 4 cycles per second) activity occurring with a stipulated density (over 16 waves per 20second epoch, or over 50% of the epoch occupied by such slow waves). Stage 3 EEG represents a lesser density (10 to 16 waves per 20-second epoch) of this slow-wave activity. Stage 3 and 4 EEG constitute, along with spindles and K-complexes, the distinguishing features of nonrapid eye-movement (NREM) or slow-wave sleep. Both stage 3 and 4 EEG are maximal during the first few hours of sleep¹and their distributions across the night may usefully be described as a function of the successive sleep cycles.² Stage 4 EEG reaches its highest level in early childhood³and then shows a hyper