[Studies on sleep and wakefulness in very old subjects].

Disturbances of nocturnal sleep and the frequency of prescription of hypnotic drugs are more frequently found in elderly people. The majority of studies on sleep in the elderly have focussed on subjects between 60 and 80 years. Even though the number of people aged 80 to 90 years has clearly increased during recent years, still only rare data are available concerning sleep in this group. The present study investigated sleep, wakefulness, and, in addition, the cognitive functions in a group of seniors not suffering from sleep disturbances, aged 80 to 90 years. The evolution of sleep and sex differences of sleep variables dependent on age with respect to the findings in an 85-year-old woman and an 82-year-old man are discussed. Polysomnographic parameters and subjective estimation of sleep quality were compared. Possible correlations of REM-sleep and the results of the Nürnberger-test-battery were evaluated. Finally, subjective estimation of daytime sleepiness with reference to sleep variables was evaluated.