System for studying the delta rhythm during sleep and its topographical amplitude distribution

An analogue system of processing all-night sleep EEG records which leads to the representation of sleep cycles by the continuous variation of the amplitude parameter in a given frequency band is described. The curves obtained are analogous to those resulting from more sophisticated computerized analyses. The cycles which they outline are in good concordance with those of the classic hypnogram. Moreover, the simplicity and the rapidity of the processing easily allow its application to multiple EEG channels. A topographical discrimination of the amplitude parameter during sleep was observed in normal subjecttion. The results obtained are illustrated in the case of a normal child and a young normal adult.