THE DIVISION of sleep into stages by Loomis et al1 and the delineation of the low voltage electroencephalogram (EEG), rapid eye movement (REM) period of sleep associated with dreaming by Aserinsky and Kleitman2 and Dement and Kleitman3 have enabled a detailed analysis of the EEG and neurophysiological activity during sleep. These advances in the understanding of normal sleep have served as a new impetus for research concerned with seizure activity during sleep, but the results have not been consistent. Inconsistency is especially noted in reports concerned with the occurrence of interictal discharges during the various sleep stages. Since most of the reports are in abstract form, comparison of results is difficult. Batini et al4 found in children that 3 cycles per second (cps) spike and wave complexes were present only at the beginning of sleep and in stage 4. Delange et al5 found an