Statistical comparison of transition sleep variables in depressed and normal subjects

Abstract

SummaryWe present the values for the amount of transitions, for the total stage duration and for the first time of occurrence (latency) of a stage. A test aimed at evaluating probability values for the transition from one sleep stage to another was applied to the hypnograms of ten patients with endogenous depression and of ten normal controls. Sleep data (EEG, EMG, EOG) of each subject were recorded on magnetic tape and paper for three consecutive nights. Following sleep stage classification, portions of hypnograms of 480 min, further divided into sub-periods, were retained for the purpose of the test. The results proved that significant differences between depressed and control subjects exist among the data corresponding to various sleep stages. These findings also provided useful statistical indications in order to reduce the amount of computing needed by an automatic classifier.