SLEEP PHASIC EVENTS IN DYSTHYMIC PATIENTS - A COMPARATIVE-STUDY WITH NORMAL CONTROLS

Among psychiatric entities, dysthymic patients provide a good model fo r studies on minor disturbances in sleep organization because they pre sent borderline abnormalities in their night sleep that concern mainly slow wave sleep. A study on sleep phasic events was performed to eval uate abnormalities in sleep microstructure. Therefore, for all subject s-normal controls and dysthymic patients-the following phasic activiti es were scored: K-complexes, vertex sharp transients, posterior occipi tal transients, delta paroxysms, theta bursts, microarousals, and awak enings. Furthermore, other sleep EEG patterns, such as REM with spindl es, and intermediate stages, were assessed. The following results were obtained: 1) dysthymic patients have less K-complexes and vertex shar p transients, with lower densities of these events; 2) they have a red uced number of microarousals, with an increased rate of awakenings; 3) patients present a higher incidence of other events such as theta bur sts, POSTs, REM with spindles, and intermediate stages. These results suggest that the analysis of phasic events is useful for the discrimin ation between normal and pathologic sleep, even when there are only mi nor differences in terms of macrostructure.