Effects of aging on EEG sleep in depression.

Many of the same electroencephalographic sleep measures which differentiate between normals and depressed patients have also shown differences among age groups within a normal population. The present study examines sleep measures in 87 inpatients with a major depressive syndrome, examining the specific sleep variables which are correlated with age between 18 and 60 years. REM latency shows a distinct decline with age, an effect not well demonstrated in normals. Thus, REM latency may differ from variables which measure aspects of awakening and which show a clear age trend in normal subjects. Since many sleep measures are greatly skewed or have truncated distributions, the present paper provides several alternative styles of measurement which allow comparisons to be made easily and also facilitate multivariate testing.