The organization of rapid eye movement activity during rapid eye movement sleep is impaired in the elderly.

Rapid eye movement activity (REMA) during rapid eye movement activity (REM) sleep was studied in eight elderly subjects and six young adults as a control group. Beyond global quantitative features (REMA density), we evaluated the organizational aspects of REMA, that is its occurrence in burst mode, still largely unknown in the aged. REMA density in the elderly is not significantly different than that of young adults. By contrast, the duration of REMA bursts is reduced in the elderly, as well as the 'burst state-to-burst-state' probability, i.e. the probability for successive inter-REMA time intervals to be part of the same REMA burst. These results show that global aspects of the quantitative features of REMA are preserved in the elderly, whereas their organizational aspects are impaired. These data are consistent with the hypothesis that aging is associated with a difficulty in maintaining physiological processes over time.