DYNAMICS OF SLOW-WAVE ACTIVITY IN NARCOLEPTIC PATIENTS UNDER BED RESTCONDITIONS

Following a baseline night recording, 9 narcoleptic subjects and 9 sex - and age-matched control subjects were maintained on 16 h of diurnal sleep deprivation. Thereafter subjects were submitted to a 32 h bed re st protocol in a sound- and light-attenuated room. The EEG was recorde d and processed by a Fast Fourier Transform. Narcoleptics did not diff er from controls in total sleep time over the whole 32 h, but spent mo re time sleeping during the daytime (DT). In both groups slow wave act ivity (SWA) showed an exponential decaying trend during the first nigh t (N1); a similar exponential trend during the second night (N2) was e vident only in controls. In controls SWA showed a circadian-circasemid ian distribution that was hardly detectable in narcoleptics, Narcolept ics showed an ultradian distribution of SWA with periodic emergence ev ery 4 h during DT and N2. Our data confirm that a homeostatic mechanis m is evident in narcoleptics when stimulated by diurnal sleep deprivat ion, while circadian and circasemidian mechanisms are less evident dur ing DT and N2. These findings suggest a different coupling between hom eostatic sleep regulating processes and circadian drives to sleep in n arcoleptics. Ultradian drives to sleep seem to be predominant in these patients, thus probably acting as a means for the avoidance of stress ful attempts to counteract a weaker waking state maintenance mechanism .