Night sleep structural alteration as a function of individual strategy of adapting to 520-day isolation

Abstract

The purpose of the study was to establish a relationship between trends in sleep alteration and individual adaptation to stress factors in the 520-day isolation study. Psychological evaluations using a battery of motivation tests, Sobchik’s modification of the Luscher personality test, and Mirror coordinograph made it possible to differentiate groups responding to the stress according to the pattern “control” (G-1) or “search” (G-2) manifested in individual styles of behavior and operator’s activity. The two groups exhibited different dynamics of the night sleep structure. Difficulties with falling asleep in G-1 arose on the eve of “landing onto Mars” and end of the experiment, whereas in G-2 they were evident prior to the end only. In addition, the micro- and segmental sleep structures were more stable in G-1, suggesting the integrity of somnogenic mechanisms despite difficult sleep initiation.