AGING AND CHANGES IN PHASIC EVENTS DURING SLEEP

Changes in phasic events in the elderly are reviewed. Such phasic even ts may in part be determined by the macrostructure of sleep (sleep sta ges). Therefore, a brief description of sleep architecture and EEG mor phology in the aged person is given. Second, there is a marked variabi lity among individuals in the number of spindles and K-complexes and m ore so in older individuals than in younger. However, there is an over all decrease in these events with age. The characteristics of these ev ents (amplitude, frequency content, and distribution) change simultane ously. Third, the number of rapid eye movement occurring during REM sl eep decreases with aging, but important gender differences exist, in t hat women generally maintain a higher REM density. The degree of chang es in phasic events might correlate with mental deterioration (sleep c ognition theory), but physical factors might also be the underlying re ason for the observed changes. Whether these changes are indicative of the individual's ability to maintain sleep remains to be determined.