SLEEP 2011 Abstract Supplement

A. Basic Science XI. Sleep Deprivation
0292
THE EFFECT OF SLEEP RESTRICTION AND DRIVING
SIMULATION WORKLOAD ON THE PSYCHOMOTOR
VIGILANCE TEST
James BC 1 , Reynolds A 1 , Knott P 1 , Reid-Dicks I 1 , Harmer L 1 , Reid KJ 2 ,
Banks S 1
1
Centre for Sleep Research, University of South Australia, Adelaide,
SA, Australia, 2 Department of Neurobiology and Physiology,
Northwestern University, Chicago, IL, USA
Introduction: Few studies have investigated the effects of workload
and sleep restriction on vigilant attention. The aim of the current study
was to examine the impact of both 4 days of sleep restriction and cognitive
workload on the Psychomotor Vigilance Test (PVT).
Methods: Participants in this preliminary study (N=10) were healthy
males (age range 23-32), with an average Body Mass Index (BMI) of
23.58kg/m2. They completed a controlled laboratory based sleep restriction
protocol of 2 nights of baseline (B1 & B2, 10h time in bed for sleep
[TIB]; 1000h-800h) followed by 4 nights of sleep restriction (SR1-4,
4h TIB a night; 400h-800h) and 1 night for recovery (10h TIB; 1000h-
800h). Participants remained in the laboratory for the entire study, food
intake, lighting and activity were strictly controlled. Testing was conducted
3 times each day at 900h, 1200h, and 1500h, and included a 10
minute Psychomotor Vigilance Test (PVT) directly before and after a,
40 minute York Driving simulation. Sleep was recorded with polysomnography.
A mixed model repeated measures ANOVA was conducted to
examine the effect of sleep restriction and driving task workload on PVT
lapses (number >500 milliseconds).
Results: Sleep restriction (F=8.03, p=0.01) increased PVT lapses before
and after the driving task (F= 8.02, p=0.03). However the interaction
effect was not statistically significant (F=0.59, p=0.58). Lane position
(F=2.24, p=0.14), road position (F=1.24, p=0.31) and crash status
(F=2.79, p=0.11) on the York driving task were not found to be significantly
affected by 4 nights of sleep restriction.
Conclusion: While driving performance was not significantly impaired
by 4 nights of sleep restriction, sleep restriction and workload associated
with the 40 minute driving task increased PVT lapses. They did not,
however, act synergistically to potentiate deficits in PVT performance.
Support (If Any): This study was supported by a University of South
Australia Women in Science grant and in part through an international
collaboration with the Sleep and Performance Centre, Washington State
University Spokane.
0293
SLEEP, SLEEPINESS AND BEHAVIOR IN FRENCH NAVY
SHIFT WORKERS: EVIDENCE FOR A DIFFERENTIAL
VULNERABILITY
Rabat A 2 , Chaumet G 2 , Schmid B 2 , Coste O 2 , Mateo-Champion M 1
1
Neurology and sleep department, “Font Pré” Hospital, Toulon, France,
2
Operational Environment Department, Military Biomedical Research
Institute, Toulon, France
Introduction: Preliminary field studies in French military unit have
shown that fatigue and sleepiness are complex concepts that cover two
different operational situations. For some navy soldiers, fatigue and
sleepiness seem mainly linked to a shift work situation whereas for the
others it seems mainly due to working conditions (workload). However
such studies do not allow determining neither the physiological consequences
of these two situations nor the factors responsible for. Here we
investigate in a controlled environment (sleep laboratory) fatigue and
sleepiness due to shift work condition.
Methods: 39 shift workers underwent a polysomnography and a multiple
sleep latency test (MSLT) before (S1) and just after a military deployment
(S2). Chronotype, subjective sleepiness, sleep quality, fatigue,
and cognitive performance (PVT, Iowa Gambling Task) were also eval-
uated during these two sessions. All subjects carried out actimeter during
the whole experiment.
Results: Preliminary results from 16 young subjects (24.7 years old
± 4.2) confirm the shift workers status with a chronic sleep restriction
(Total sleep time < 6 hour/day). After the deployment there is an increase
of subjective fatigue (Pichot: 15 versus 9.5, p < 0.01) with diurnal
sleepiness (MLST, S1 = 12 min; S2 = 10.2 min, p < 0.05). There is no
modification of sleep quantity (S1=538, S2=530 min p > 0.80) and quality.
Interestingly, we observe resistant (R) and vulnerable (V) subjects
profiles for performance in PVT (Lapses # for R, S1=9.2, S2=4.7, p >
0.17 and V, S1=7.5, S2=16.6, p < 0.01) with parallel modification of
sleepiness (MSLT for R, S1= 11.6, S2=10.5 p > 0.5 and for V, S1=12.3,
S2=9.6, p < 0.01). After the deployment, we also have 2 profiles in the
gambling task: risky and cautious behavior. They are respectively associated
with long lasting sleepiness (MSLT < 10 min in S1 & S2) or no
sleepiness (S1=14 and S2=11 min).
Conclusion: These preliminary results are in accordance with field studies
showing cognitive deficits and risky decision behavior in navy soldiers
who complaint from fatigue, sleepiness and sleep quality. We show
here that in chronic sleep restriction induced by shift working some
French navy soldiers are vulnerable in terms of objective sleepiness, attention
processes and risky behavior and others are resistant. Determinants
of this vulnerability are key question for our future studies.
Support (If Any): Grants from the General Delegation of Arming
#10ca707
0294
LOCAL, USE-DEPENDENT CHANGES IN THE WAKING EEG
AFTER PROLONGED WAKEFULNESS
Hung C 1 , Sarasso S 1 , Ferrarelli F 1,2 , Riedner BA 1 , Cirelli C 1 , Tononi G 1
1
Psychiatry, University of Wisconsin-Madison, Madison, WI, USA,
2
Psychiatry, Catholic University of the Sacred Heart, Rome, Italy
Introduction: In humans, prolonged wakefulness is commonly associated
with increased sleepiness and impairment in behavioral performance.
Previous work has shown that sustained wakefulness is associated with
a progressive, homeostatic increase in EEG power density in the theta/
alpha frequency range. In this study we investigated whether specific
behavioral manipulations targeting distinct cortical areas could locally
regulate these changes during prolonged wakefulness.
Methods: Sixteen subjects (right-handed, 22+/-2.7y, 7 females) participated
in two prolonged wakefulness experiments (24-h). During each
experiment, subjects were exposed to six 2-h bouts of either audiobook
listening (AB) or driving simulator playing (DS). These tasks were chosen
as previous imaging studies showed that speech listening tasks and
driving simulation tasks involve different cortical areas, with the former
activating the left fronto-temporal cortices and the latter activating
occipito-parietal networks. Resting waking high density EEG (256
channels) with eyes open was recorded for 4 min before and after each
task bout, preceded by subjective sleepiness evaluation and a 10-min
psychomotor vigilance test (PVT).
Results: After 24-h prolonged wakefulness, both tasks induced a global
homeostatic increase in the resting waking EEG power in the theta/alpha
frequency (6-9 Hz), concurrent with increased subjective sleepiness and
PVT reaction times (p