SLEEP 2011 Abstract Supplement

A. Basic Science XI. Sleep Deprivation
0289
EFFECTS OF COGNITIVE WORKLOAD AND SLEEP
RESTRICTION ON THE MAINTENANCE OF WAKEFULNESS
TEST
Arroyo S, Goel N, Dinges DF
Division of Sleep and Chronobiology, Department of Psychiatry,
University of Pennsylvania School of Medicine, Philadelphia, PA, USA
Introduction: The Maintenance of Wakefulness Test (MWT) measures
the ability to resist sleep in an environment of decreased stimulation.
Sleep deprivation reduces MWT sleep latency onset, but it is not known
if cognitive work affects the MWT. This study investigated the effects of
high cognitive workload (HW) versus low cognitive workload (LW) on
MWT sleep latency following both sleep restriction (SR) and no sleep
restriction (NSR).
Methods: As part of a larger experiment, N=47 healthy adults
(33.1±8.9y; 21 females) completed 3 baseline nights (8h TIB), followed
by 5 SR nights (4h TIB) or NSR nights (8h TIB) in a laboratory setting.
Subjects were randomized to 1 of 4 experimental conditions: HW+SR
(N=16); HW+NSR (N=15); LW+SR (N=10); LW+NSR (N=6). The
HW vs. LW conditions differed in duration of cognitive testing each
day (LW=½HW). Modified 30-min single-trial MWTs were conducted
at 1445h-1600h after baseline night 3 (B3) and after SR1, SR4 and SR5
nights or equivalent NSR nights. Sleep latency was defined as time to
the first microsleep (10s EEG theta) or 30 min if no sleep occurred.
One-way and mixed-model (night×condition) ANOVAs compared differences
among conditions; paired t-tests compared B3 to SR5/NSR5
within each group.
Results: MWT latencies for the 4 groups did not differ at B3. Latencies
decreased significantly from B3 to SR5 (p=0.006) in the sleep restriction
conditions. The day x condition interaction (p=0.003) indicated the
HW+SR group had a greater decrease in MWT latency (p