REM sleep in primary depression: a computerized analysis

REM sleep in 35 inpatients with primary depression was automatically analyzed for 7 consecutive nights during placebo administration. For the total night of sleep, as well as each individual REM period, the number of REMs, their total voltage integral over time, the sum of their durations and the average REM size were automatically calculated. Validity of these automated REM measures was established by significant correlations with manually scored REM measures. Changes in REM sleep across the night were also investigated. Similar to findings in normal subjects, REM time did not change from REM period to REM period. Average REM size increased significantly from REM period 2-3 and 3-4. Contrary to what is seen in normal subjects, REM frequency was high during the first REM period, significantly decreased from the first to second REM period and then remained constant. Finally, a significant inverse correlation between REM frequency for the first REM period and REM latency was noted. This pattern of REM sleep is interpreted as indicating a high pressure for phasic REM at the beginning of the night which is dissipated by the first REM period.