[Quantitative analysis of the electroencephalographic activity during human sleep]

Correlation of hormonal changes and EEG activity requires objective measurements to define the behavior of the different frequency bands during sleep. With this purpose, EEG activity of six healthy male volunteers (19-22 years) was recorded throughout all night during spontaneous sleep. The C4-left mastoid EEG combination was channeled to a frequency analyzer with four band pass filters (beta, alpha, theta, and delta) using a one minute averaging interval. Analyzer data were fed to an IBM-1130 computer, programmed with RC filter recursive algorithm. Sleep stages were characterized in the polygraphic record (Rechtshaffen criteria), and identified in the smoothed profile. The latter was computed for mean voltage value of each band during the sleep stages. Differences in the behavior of each band throughout sleep stages were statistically tested. Delta activity showed the highest discriminatory capacity characterized by a statistically different mean voltage value in all sleep stages, with the exception of R-I. The method is proposed for quantitative correlation of the EEG sleep phenomena with another physiological parameters.