Systematic Trends Across the Night in Human Sleep Cycles.

The durations of successive sleep cycles, defined according to NREM (stage 2) or REM onsets, were subjected to trend analysis in three groups of normal subjects and in a group of elderly patients with chronic brain syndrome (CBS). NREM sleep cycles showed consistent curvilinear trends for all groups except that the trend in children was distinguished by a lengthy first NREM cycle. REM sleep cycles showed quite similar curvilinear trends for the three normal age groups with the middle two cycles being longer than the first and fourth. In the CBS patients, REM sleep cycles did not show a significant trend across the night. Real-time cycles (i.e., with time awake included) manifested trends quite similar to those excluding waking. The trends in sleep cycle durations are normative characteristics of sleep which may not be apparent on a single night. A more constant cycle was found in the CBS elderly and may indicate brain pathology. Sleep cycle trends, along with such other temporal characteristics as the decline in stage 4, may provide clues to the metabolic processes which underlie the sleep EEG. They also provide a more exact basis for investigation of hypothesized biorhythm correlates of NREM-REM cycles. [ABSTRACT FROM AUTHOR]

Copyright of Psychophysiology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)