Polygraphic sleep criteria as predictors of successful aging: An exploratory longitudinal study

Background: A cohort of 57 elderly healthy volunteers (34 male, 23 female) was studied in a sleep laboratory or? four consecutive nights when their av erage age was 63.5 +/- 3.7 years. Thirty subjects (20 male, 10 female) were assessed 14 years later,. 21 had either died in the meantime or were very, ill, and 6 did not participate for other reasons. Methods: Two operationalizations of successful aging were applied: survival in relatively good health (30 survivors vs. 21 nonsurvivors), and cognitiv e competence as assessed in the survivors by means of tests of cognitive fu nction. Results: Whereas none of the sleep characteristics determined at baseline d istinguished the survivors from the nonsurvivors, several parameters [REM ( rapid eye movement) sleep latency, REM density, and NREM (non-REM) shifts] were significantly correlated with one or more measures of cognitive functi oning at follow-lip. These polygraphic sleep parameters also distinguished a subgroup of cognitively fully competent subjects fr-om those who, accordi ng to their performance in tests of cognitive function, could be considered as mildly demented Conclusions: While the REM latency and density findings support the theory of a functional link between brain cholinergic activity, timing, and densit y of REM sleep and cognitive functioning, the positive association between the number of NREM shifts at baseline and cognitive performance 14 years la ter is difficult to explain. It is suggested that the findings of the prese nt study, in particular the potential predictive value of REM latency and R EM density for cognitive functioning in the old, Meed replication in other subject samples followed for similar lime periods. (C) 1999 Society of Biol ogical Psychiatry.