Interictal epileptiform discharges and phasic phenomena of REM sleep

The objective of this study was to assess the effect of phasic rapid eye movement (REM) sleep events on interictal epileptiform discharges (IEDs). Twelve patients with focal epilepsy and IEDs during REM sleep were examined by video-EEG monitoring. The number of IEDs was calculated in different REM sleep episodes according to the rate of rapid eye movements. A negative correlation was identified between the occurrence of rapid eye movements and IEDs, indicating that the suppression of propagation of IEDs during REM sleep is enhanced by phasic REM sleep events, probably as a result of phasic activation of cholinergic neurons of the ponto-mesencephalic tegmentum. This study demonstrates that the degree of EEG desynchronization and IEDs is influenced by REM density.