Comparison of automated REM and slow-wave sleep analysis in young and middle-aged depressed subjects.

A comparison of electroencephalographic sleep measures between young and middle-aged groups of depressed inpatients was conducted with specific interest in the application of automated measures of REM and delta wave sleep. Aside from the expected differences in sleep continuity, increased Stage 1 percent, decreased Stage 2 percent, and decreased REM latency in the middle-aged depressives as compared to the younger depressives, distinct findings from automated analyses were noted in the distribution of REM and delta sleep throughout the night. Although the younger depressed patients showed increased numbers of delta waves, the middle-aged depressives showed greater average REM count. Such changes were more pronounced in the first third of the night. Finally, in the middle-aged depressives, little statistical relationship between manual measures of slow-wave sleep and automated measures of delta sleep was found.