Evidence from epileptic patients on the role of the right hemisphere in REM sleep.

Eight highly selected epileptic patients found to have lasting right temporal or temporooccipital rhythmic focal activity during night sleep were reassessed following remission which occurred between a few days and 7 years after the initial finding. In polysomnographic EEG recording, when the patients had extensive epileptic discharges in the right temporal and temporo-occipital regions, a prolonged period of REM sleep occurred (34.1 +/- 7.06% of total sleep time). Following remission, however, disproportion had returned to normal (20.4 +/- 1.75%). These results confirm that intensive focal epileptic activity in the temporal and temporooccipital regions of the right hemisphere during sleep facilitate REM sleep thus indicating a dominant role for the right hemisphere in REM sleep and dreaming.