Sex Differences in Slow-Wave Activity in Response to Sleep Deprivation Roseanne Armitage, Carlyle Smith*, Sandra Thompson* and Robert Hoffmann
Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas, USA *Department of Psychology, Trent University, Peterborough, Ontario, CANADA

A sleep deprivation paradigm was utilized as a means of assessing sex differences in slow-wave sleep regulation. Quantitative EEG activity was evaluated in 16 healthy young adults (8 men and 8 women) during baseline and in recovery sleep after 40 hours of total sleep deprivation. Significant increases in slow-wave activity (SWA) incidence, amplitude and power were evident in the first half of recovery sleep, particularly in the first NREM period. However, sex differences were also evident in SWA response to sleep deprivation. Women showed a more dramatic increase in SWA in comparison to men. This sex difference was robust and evident in both central parietal EEG regardless of whether data were analyzed by NREM period or independent of sleep stage. These findings suggest that slow-wave sleep regulatory mechanisms and associated homeostatic processes may differ between men and women under biological "challenge" conditions.