Distribution of delta activity across nonrapid eye movement sleep episodes in healthy young men

• Published in: Sleep (New York, N.Y.) N.Y.), 1997-04, Vol.20 (4), p.313-320
• Main Authors: PREUD'HOMME, X. A, LANQUART, J.-P, MENDLEWICZ, J, LINKOWSKI, P
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Biological and medical sciences; Cerebral Cortex - physiology; Delta Rhythm; Fourier Analysis; Fundamental and applied biological sciences. Psychology; Humans; Male; Polysomnography; Reference Values; Signal Processing, Computer-Assisted; Sleep Stages - physiology; Sleep. Vigilance; Vertebrates: nervous system and sense organs
• ISSN: 0161-8105; 1550-9109
• DOI: 10.1093/sleep/20.4.313

The distribution of delta activity across successive nonrapid eye movement (NREM) sleep episodes and its night-to-night stability across three consecutive nights were investigated by studying delta power with spectral analysis in 31 healthy young men. Repeated-measures analysis of variance (ANOVA) with polynomial contrast was applied to grouped data of absolute delta power and three indexes: (1) the rate of delta power per NREM episode to its duration, 2) the standardized rate for the last NREM episode, and 3) the logarithm of the standardized rate. A significant linear decrease across NREM episodes was observed for each variable in each successive night. In addition, using night as a second within-subjects factor, no night effect was observed. Yet, the subsequent analysis of the logarithmic data yielded greater F values in all three nights' data as well as a linear function that accounted for a greater proportion of total variance than the analysis of the nonlogarithmic data. Since a linear decline for the logarithm of a variable implies an exponential distribution for that variable, we conclude that delta activity is distributed exponentially across NREM episodes, and this finding shows a remarkable night-to-night stability.