The chief complaint of individuals deprived of REM and slow wave sleep (SWS) is sleepiness.  Inhibitions may be somewhat loosened.  One report cited the expression of “ideas and thoughts which were quite lewd”.

    The frequency of stimulation required depriving individuals of each stage of sleep increased as the period of deprivation went on.  One study reported that the amount of stimulation required to deprive a participant of stage 4 was four times as much as than the amount of stimulation required to REM deprive a person. The number of epochs of requiring stimulation to deprive a person of stage 4 was the greatest during the first third of the night.  Later in the night, more epochs of stimulation were required to deprive a person with REM.

The authors propose the question of the relative importance of REM and stage 4 based upon the results of the deprivation.  They conclude that the greater amount of stimulation required to achieve stage 4 deprivation may indicate greater need for stage 4, while the longer recovery period for REM deprivation may indicate greater importance.

    There are serious methodological problems that confound any valid comparison of the effects of REM and stage 4 deprivation.  The method used to prevent a participant from going into stage 4 was the sounding of a tone.  The tone was continually presented until the EEG of the person became more frequent, showing a stage of sleep other than stage 4.  The participants were not awakened when they entered stage 4.  In contrast, REM was prevented by waking the participant.  The independent variable is confounded with the awakenings from the REM deprivations.

    The greater number of epochs of stimulation needed to deprive a person of stage 4 may be a result of the fact that the sleep of the person was not terminated in order to achieve the deprivation, which allowed the person to re-attempt to enter that stage of sleep more quickly.  In addition, the frequency of the stimulation over the course of the night for each type of deprivation is consistent with the overall sleep cycle, and may not be a result of sleep deprivation.  In a typical night of sleep, all of the slow wave sleep is experienced within the first 4.5 hours.  The rest of the night is typically stages 1, 2, and REM.