The influence of sleep deprivation on the contingent negative variation.

The physiological functions (contingent negative variation (CNV), critical nicker fusion frcyueney (CFF), oral temperature. blood pressure and heart rate) of five subjects were measured every three hours in 36-hour sleep deprivation and twice after the recovery night. The subjects 'Nere given tasks (UchidaKraepelin test. etc.) and were made to fill out a self-rating yuestionnaire of suhjective symptoms and thc Stanford sleepiness scale (SSS) hefore every mcasurement. The CI\V area decreased sharply at and after 3:00 of the second day. and dropped to its minimum at 9:00 of the same day and still did not increase aiter the recovery night. The numher of suhjective symptoms reached its maximum at 6:00 and 9:00 of the second day. A close correlation was found hetween the numher of suhjectivc symptoms and the eNV area during sleep deprivation. The SSS was at its maximum at 6:00 of the second day and a good correlation was found hetween the SSS and the CNV area. The correlation hetween the C~V area and Crr and hetween the CNV area and oral temperature was slight. The CNV is meaningful as an index which objectively indicates the drop in arousal level caused hy sleep deprivation.