SLEEP 2011 Abstract Supplement

B. Clinical Sleep Science II. Sleep Disorders – Circadian Rhythms
persons variables could be found which have a positive effect on negative
results of shift work. Out of this individual industrial strategies of
prevention can be deduced and implemented.
0479
SLEEP DISORDERS AND DEPRESSION IN SHIFT WORKERS
IN COMPARISON WITH DAY WORKERS
Maghsoudipour M 1 , Saberi H 2
1
University of Social Welfare and Rehabilitation Sciences, Tehran,
Islamic Republic of Iran, 2 Kashan University of Medical Sciences,
Kashan, Islamic Republic of Iran
Introduction: Shift work refers to a job schedule in which employees
work hours other than the standard hours or a schedule other than
the standard workweek. To evaluate the effect of shift work on Iranian
workers’ health we studied the workers of Granite Behseram Company.
Methods: A cross sectional study was performed to identify frequency
of psychosomatic and sleep disorders in day workers and shift workers
in Granite Behseram Company. The information on 156 workers about
sleep disorders was gathered using Epworth Sleepiness Scale (ESS),
CCNY ( for insomnia), and SDQ. We also used Beck Questionnaire for
evaluation of depression. Specific chart was designed to determine if
gastrointestinal problems existed. Data was analysed using Chi-square
test.
Results: Of 156 workers with a mean age of 33.0 ± 5.3, 65 workers
(41.7%)were day workers and 91 (58.3%) were shift workers. All the
workers were male. Sleep disorders, insomnia, excessive daytime sleepiness
and depression were more prevalent in shift workers although it
was not significant. Occupational accidents were significantly higher
in shift workers (p=0.01). Among gastrointestinal problems, abdominal
cramps was the only symptom significantly higher in shift workers
(p=0.03).
Conclusion: Although psychosomatic and sleep disorders were not significantly
higher in shift workers, more prevalent accidents necessitate
new strategies to prevent injuries.
0480
PHYSIOLOGICAL CHARACTERISTICS OF PATIENTS WITH
CIRCADIAN RHYTHM SLEEP DISORDER (FREE-RUNNING
TYPE)
Kitamura S 1 , Hida A 1 , Watanabe M 1 , Enomoto M 1 , Aritake-Okada S 2,3 ,
Moriguchi Y 1 , Kamei Y 1 , Mishima K 1
1
Department of Psychophysiology, National Institute of Mental
Health, National Center of Neurology and Psychiatry, Tokyo, Japan,
2
Department of Somnology, Tokyo Medical University, Tokyo, Japan,
3
Research Fellow of the Japan Society for the Promotion of Science,
Tokyo, Japan
Introduction: Most behavioral and physiological function in living
organisms on earth exhibit 24-hour period. The central circadian pacemaker
in mammals resides in the suprachiasmatic nuclei (SCN) of the
anterior hypothalamus. The intrinsic period (τ) generated by the pacemaker
is not exactly 24 h and the biological clock therefore needs to be
entrained to the 24-hour day. Disorganized circadian system could cause
various diseases including sleep disorders. Circadian rhythm sleep disorder,
free-running type (CRSD-FRT) is one of the CRSD characterized
by the sleep timing that occur 30min-1h delay each day. Little is known
about the mechanism underlying CRSD-FRT. In this study, we examined
rhythmic characteristics of physiological functions in CRSD-FRT
patients and controls.
Methods: Rhythmic characteristics of physiological functions (core
body temperature and plasma melatonin etc.) of six CRSD-FRT patients
diagnosed according to ICSD-2 criteria (mean age 34.17(SD 12.59),
range 17-56 yrs, 66.7 %female) were examined under a 28-h forced
desynchrony protocol. The intrinsic circadian period was estimated by
temperature minimum (nadir) and corticosteroid maximum (acrophase)
and dim-light melatonin onsets (DLMO) between CRs before and after
FD.
Results: Patients with CRSD-FRT showed the longer intrinsic circadian
periods than healthy subjects with the intermediate chronotype, the period
length of CRSD-FRT was similar to that of some evening chronotype.
Conclusion: These findings indicate that not only the intrinsic circadian
period but also other functions (ability of entrainment to the environment,
homeostatic sleep regulation) might have pathogenic significance
in CRSD-FRT.
0481
BLIND FREE-RUNNERS CAN SPONTANEOUSLY
ENTRAIN TO UNKNOWN ZEITGEBERS FOR UP TO 345
CONSECUTIVE DAYS
Emens J, Laurie A, Lewy A
Psychiatry, Oregon Health & Science University, Portland, OR, USA
Introduction: The biological clock is no longer synchronized to the
24-hour day in the majority blind individuals lacking light perception,
resulting in recurrent insomnia and daytime somnolence as the timing of
the clock (circadian phase) drifts in and out of synchrony with the timing
of sleep. We have previously described a pattern of relative coordination
(RC) in such blind free-runners (BFRs) wherein the drift in phase
to a later, or earlier, time regularly slows and accelerates in response to
weak time cues, but entrainment to the 24-hour day does not occur. We
describe here four BFRs who, after a period of free-running with RC,
spontaneously had circadian periods that were indistinguishable from
24-hours which we define as transient entrainment.
Methods: Subjects were 20 BFRs lacking conscious light perception
(11 F, 9 M; 9-78 y.o.). Saliva samples were collected every 1-2 h for
14-25 h at the Oregon Health & Science University Clinical and Translational
Research Center (CTRC) or at home approximately every 2
weeks. Melatonin concentrations were measured by radioimmunoassay
(ALPCO) and the salivary melatonin onsets (MOs) were assessed using
a 3 pg/ml threshold. Circadian period was calculated by linear regression
through a series of MOs. As we have done previously, entrainment was
defined as a period, based on at least 4 MOs, >= 23.96 h and