• Sleep Medicine and Psychophysiology
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• v.19 no.2
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• pp.77-83
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• 2012

Objectives: Recent studies have reported a correlation between obstructive sleep apnea syndrome (OSA) and depression. In attempt to verify the suggestion that eveningness is related to depression, we examined the effect of morningness-eveningness on their depressive mood in patinets with OSA. Methods: The examination was based on the medical records and polysomnography reports of 211 OSA patients. Information was gathered from the patients who filled out the H$\ddot{o}$rne and Ostberg questionnaire (HOQ), profile of mood states-Korean version (K-POMS), and Epworth sleepiness scale (ESS). We compared mean values of K-POMS total, subscales of K-POMS, ESS, and OSA severity variables among the 3 morningness-eveningness groups (morningness, eveningness, and neither groups). Partial correlation analysis was performed between variables and ANCOVA was performed among the 3 groups after adjustment with age and weight. Results: There were significant negative correlations between HOQ and the followings : K-POMS total, POMS-T (tension-anxiety), POMS-D (depression-dejection), POMS-A (anger-hostility), POMS-F (fatigue-inertia), POMS-C (confusion-bewilderment), spontaneous arousal index, average O2 saturation. There were significant positive correlations between HOQ and the followings : POMS-V (vigor-activity), apnea-hypopnea index, respiratory arousal index, snore time. There were significant negative correlations between POMS-D and the followings : HOQ, POMS-V, stage 1 sleep (%), AHI, TAI (total arousal index), oxygen desaturation index, respiratory arousal index, neck circumference, average O2 desaturation, snore time (%). There were significant positive correlations between POMS-D and K-POMS total, POMS-T, POMS-A, POMS-F, POMS-C, sleep latency, stage 2 sleep (%), heart rate, spontaneous arousal index. There were significant differences in K-POMS total, POMS-T, POMS-D, POMS-F, POMS-C, spontaneous arousal index among the three HOQ groups in ANCOVA. Conclusion: The depressive correlates of OSA patients might be affected, not by excessive daytime sleepiness or OSA severity indexes, but by eveningness circadian characteristics. It would be important to take into account the morningness-eveningness tendency when we manage the depressive mood of OSA patients.

• Sleep Medicine and Psychophysiology
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• v.19 no.2
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• pp.84-88
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• 2012

Introduction: The objective of the present study was to investigate the independent effects of major depressive disorder (MDD) and insomnia on somatization, respectively. Methods: A total of 181 participants (73 males and 108 females ; mean age $41.59{\pm}8.92$) without serious medical problem were recruited from a community and a psychiatric clinic in Republic of Korea. Subjects were divided into 4 groups based on the Structured Clinical Interview for DSM-IV axis I disorder (SCID-IV) and sleep questionnaire : 1) normal controls (n=127), 2) primary insomnia (n=11), 3) MDD without insomnia (n=14), and 4) MDD with insomnia (n=29). All participants were requested to complete the somatization subscores of the Symptom Checklist-90-Revised (SCL-90-R). Results: There were significant between-group differences in somatization score (F=25.30, p<0.001). Subjects with both MDD and insomnia showed higher somatization score compared to normal control (p<0.001), subjects with primary insomnia (p=0.01), or MDD subjects without insomnia (p<0.001). Subjects with primary insomnia had higher somatization score than normal controls (p<0.01), while there was no significant difference between MDD subjects without insomnia and normal controls. In multiple regression, presence of insomnia predicted higher somatization score (beta=0.44, p<0.001), while there was only non-significant association between MDD and somatization (beta=0.14, p=0.08). Conclusion: In the current study, insomnia was associated with somatization independently from major depression. Subjects with primary insomnia showed higher somatization. Within MDD patients, presence of insomnia was related to higher somatization. Our finding suggests that insomnia may partly mediate the relationship between depression and somatization.

• Sleep Medicine and Psychophysiology
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• v.15 no.1
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• pp.25-32
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• 2008

Objectives: A few studies have compared REM sleep-dependent obstructive sleep apnea syndrome (REM-OSA) with sleep stage non-dependent apnea syndrome (SND-OSA). Despite that REM-OSA might be more common in women than men, no studies have examined the probable characteristics of women patients with obstructive sleep apnea syndrome (OSAS). This study aimed at finding out the characteristics of REM-OSA in women by comparing it with SND-OSA. Methods: Fifty-three subjects diagnosed as OSAS (AHI>5 ; AHI : apnea-hypopnea index) with nocturnal polysomnography at the Center for Sleep and Chronobiology of the Seoul National University Hospital between October 2004 and February 2006 were studied. Of them, 44 subjects with OSAS severity of mild (52 and AHI-NR<15 (AHI-R : AHI during REM sleep, AHI-NR : AHI during non-REM sleep). We compared REM-OSA group with SND-OSA as well as the criteria-determined REM-OSA cases with the visually-determined ones. Results: Among 44 subjects, 28 persons (63.6%) turned out to have REM-OSA by our criteria and 24 persons (54.5%) by visual determination. Statistically significant differences (p<0.05) were found between REM-OSA and SND-OSA groups in AHI, hypopnea index, total sleep time, total wake time, sleep efficiency index, percents of stage 1, 2 and REM sleep, and REM latency. Percent of stage REM sleep (%REM) turned out to have influence on AHI ratio (AHI-R/AHI-NR) (B=0.537, p=0.002). REM-OSA was likely to be diagnosed in milder severity of OSAS (${\chi}^2=13.117$, p<0.001) and those with higher %REM (${\chi}^2=11.325$, p=0.001). There was no significant difference between the criteria-determined and the visually-determined cases of REM-OSA. Conclusion: We suggest that REM-OSA and SND-OSA patients be differentiated in terms of pathophysiology and treatment strategies. Visual determination of REM-OSA might be useful as the screening procedure of REM-OSA. Further studies on women with OSAS and REM-OSA need to be done.

• Sleep Medicine and Psychophysiology
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• v.14 no.1
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• pp.33-41
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• 2007

Objectives: It has been known that the contents of dreams change according to neuro-developmental differences in sex, progression of age and various environments, unlike the established psychoanalytic theory. To investigate the changes, we collected "most recent dream report" and analyzed the contents of dreams by using Hall/Van de Castle System. Method: Most recent dream reports were gathered from age 12-14 years old, 2,673 middle school students (1,544 male 1,129 female) and analyzed those reports using Hall/Van de Castle System. The data were sorted in SAS and dream SAT. Result: There were prominent differences between male and female middle school students in Male/Female Percentage (male/ female；56%/35%), Familiarity Percentage (57%/69%), Aggression/Friendliness Percentage (79%/65%), Befriender Percentage (50%/33%), Physical Aggression Percentage (90%/70%), Indoor Setting Percentage (40%/55%), Negative Emotion Percentage (56%/68%) and Torso/Anatomy Percentage (51%/36%). There were significant differences in Male/Female Percentage (65%/44%), Friendliness, Physical Aggression and Self Negativity Percentage in male and there were significant differences in Friendliness, Familiarity and Friends Percent in female between 1st and 2nd grade. But, it showed much similar dream patterns between 2nd and 3rd grade in both gender. In male, Aggression/Character Index with male character is significantly increased by 2nd grade (1st/ 2nd/ 3rd；0.48/ 1.04/0.98), In female, Friendliness/Character Index with male character had significantly decreased by 2nd grade (0.38/ 0.19/0.20). Conclusion: There were apparent differences between age 12-14 years old male and female. Male adolescents have differences mostly in categories related with aggression, but female adolescents have differences in categories related with environment or character. It shows that developmental level of male are slower than female as of yet and male needs more active interpersonal relationship to find identity. Otherwise, the influences of passive attitude and actual circumferential environment are reflected in female's dream. There are no prominent differences among ages, but age 12-13 years old adolescents shows significant differences in interacting with the other gender. It means that circumferential environment and interpersonal relationship affect the contents of dreams and also the cognitive development related to age and sex. Afterwards, the development of dreams could be better understood through the neurocognitive study and dream analysis between other ages and nations.

• Sleep Medicine and Psychophysiology
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• v.14 no.1
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• pp.20-25
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• 2007

The present study compared the actigraphic indices between both wrist actigraphies (WATGs), and the sleep estimates between each WATG and nocturnal polysomnography (NPSG) to assess their differences and consistencies. We studied 22 right-handed subjects (mean age $43.9{\pm}13.3\;years$, M：F=14：8) with untreated primary sleep disorders (primary insomnia=8, simple snorer=2, obstructive sleep apnea=12) undergone by overnight both WATGs and NPSG, simultaneously. Comparison and correlation were analyzed between right and left wrist actigraphic data. In the sleep estimates of both WATGs and NPSG, each WATG was compared and correlated with NPSG in sleep period time (SPT), total sleep time (TST), sleep latency (SL), sleep efficiency (SE) and wake time (WT). Sleep indices between both WATGs showed significant positive correlations with no correlations in SL and fragmentation index (FI). There were no differences in sleep indices between both WATGs. SPTs of both WATGs, SL of left WATG, and TST of right WATG showed positively significant correlations, and SE of right WATG did negatively significant correlation in sleep indices between each WATG and NPSG. As each WATG was compared to PSG, SPTs of both WATGs and WT of right WATG were decreased, and TST and SE of right WATG and SL of left WATG were increased. Inconsistent SL and FI between both WATGs indicate that the activities between both WATGs can differentially happen during wake or arousal. Inconsistent sleep estimates between each WATG and NPSG may indicate the limited usefulness in measuring and analyzing one-night sleep by using WATG.

• Sleep Medicine and Psychophysiology
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• v.21 no.1
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• pp.21-28
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• 2014

Objective: Few studies have evaluated the personality characteristics of patients with obstructive sleep apnea (OSA) and simple snoring. We investigated the personality characteristics of OSA and simple snoring patients and compared differences in personality between the two groups using the Eysenck Personality Questionnaire (EPQ). Materials and Methods: Two hundred and thirty-seven patients who were suspected to have OSA or simple snoring participated in this study. A self-questionnaire which included the EPQ was administered to all participants. All subjects underwent polysomnography in a sleep laboratory and those with an apnea-hypopnea index (AHI) ${\geq}5$ were included in the OSA group, while those with an AHI <5 were included in the simple snoring group. Results: OSA patients had significantly lower scores for Psychoticism (F=4.563, p=0.034) than simple snorers. There were no significant differences in Extraversion (F=3.029, p=0.083), Lie (F=0.398, p=0.529), or Neuroticism (F=3.367, p=0.068) scores between the two groups. In the correlation analysis of the OSA group, AHI was positively correlated with Extraversion score (r= 0.16, p=0.029) and negatively correlated with Lie score (B=-0.31, p<0.001). Using multiple stepwise linear regression analysis with the four EPQ parameter scores as dependent variables, Lie score was associated with older age (B=0.14, p<0.001) and lower AHI (B=-0.05, p<0.001), Psychoticism score was associated with higher Pittsburgh Sleep Quality Index (PSQI ; B=0.14, p<0.001), Neuroticism score was associated with higher PSQI (B=0.34, p=0.001) and female sex (B=3.15, p=0.003), and Extraversion score was associated with younger age (B=-0.08, p=0.020) and higher body mass index (B=0.26, p=0.023). Conclusion: This study suggests that patients with OSA are significantly less prone to psychotic personality characteristics than those with simple snoring. Among OSA patients, higher AHI was correlated with low falsehood and high extraversion tendencies.

• Sleep Medicine and Psychophysiology
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• v.21 no.1
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• pp.14-20
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• 2014

Objectives: Several studies suggest that nocturia may be related to obstructive sleep apnea syndrome (OSAS). The mechanism by which OSAS develops nocturia has not been determined. The present study aimed to determine the prevalence of nocturia among adults with OSAS and to identify factors that may be predictive in this regard. Methods: Retrospective review of clinical and polysomnographic data obtained from patients evaluated at the sleep clinics of the St. Paul's Hospital between 2009 and 2012. The urinary symptoms were assessed on the basis of the International Prostate Symptom Score (IPSS). Pathologic nocturia was defined as two or more urination events per night. OSAS was defined as apnea-hypopnea index (AHI) ${\geq}5$. A multivariate analysis using logistic regression was performed to examine the relationship between polysomnographic variables and the presence of pathologic nocturia, while controlling for confounding factor. Results: A total of 161 men >18 years of age (mean age $46.7{\pm}14.1$), who had been referred to a sleep laboratory, were included in the present study. Among these, 27 patients with primary snoring and 134 patients with obstructive sleep apnea were confirmed by polysomnography. Nocturia was found in 53 patients with OSAS (39.6%) and 8 patients with primary snoring (29.6%). The AHI was higher in patients with nocturia than in those without nocturia (p=0.001). OSAS patients with nocturia had higher arousal index (p=0.044), and lower nadir oxyhemoglobin saturation (p=0.001). Multiple regression analysis showed that age (${\beta}$=0.227, p=0.003), and AHI (${\beta}$=0.258, p=0.001) were associated with nocturia, and that the presence of pathologic nocturia was predicted by age (OR 1.04 ; p=0.004) and AHI (OR 1.02 ; p=0.001). Conclusion: Nocturia is common among patients with OSAS. The strongest predictors of nocturia are age and AHI in patients with OSAS.

• Sleep Medicine and Psychophysiology
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• v.21 no.1
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• pp.5-13
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• 2014

Objectives: Depression, sleep complaints and cognitive impairments are commonly observed in the elderly. Elderly subjects with depressive symptoms have been found to show both poor cognitive performances and sleep disturbances. However, the relationship between sleep complaints and cognitive dysfunction in elderly depression is not clear. The aim of this study is to identify the association between sleep disturbances and cognitive decline in late-life depression. Methods: A total of 282 elderly people who underwent nocturnal polysomnography in a sleep laboratory were enrolled in the study. The Korean version of the Neuropsychological Assessment Battery developed by the Consortium to Establish a Registry for Alzheimer's Disease (CERAD-K) was applied to evaluate cognitive function. Depressive symptoms were assessed with the geriatric depression scale (GDS) and subjective sleep quality was measured using the Pittsburg sleep quality index (PSQI). Results: The control group ($GDS{\leq}9$) when compared with mild ($10{\leq}GDS{\leq}16$) and severe ($17{\leq}GDS$) depression groups, had significantly different scores in the Trail making test part B (TMT-B), Benton visual retention test part A (BVRT-A), and Stroop color and word test (SCWT)(all tests p<0.05). The PSQI score, REM sleep duration, apnea-hypopnea index and oxygen desaturation index were significantly different across the three groups (all indices, p<0.05). A stepwise multiple regression model showed that educational level, age and GDS score were predictive for both TMT-B time (adjusted $R^2$=35.6%, p<0.001) and BVRT-A score (adjusted $R^2$=28.3%, p<0.001). SCWT score was predicted by educational level, age, apnea-hypopnea index (AHI) and GDS score (adjusted $R^2$=20.6%, p<0.001). Poor sleep quality and sleep structure alterations observed in depression did not have any significant effects on cognitive deterioration. Conclusion: Older adults with depressive symptoms showed mild sleep alterations and poor cognitive performances. However, we found no association between sleep disturbances (except sleep apnea) and cognitive difficulties in elderly subjects with depressive symptoms. It is possible that the impact of sleep disruptions on cognitive abilities was hindered by the confounding effect of age, education and depressive symptoms.

• Sleep Medicine and Psychophysiology
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• v.9 no.2
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• pp.106-114
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• 2002

Objectives: Daytime sleepiness is a common symptom and is associated with sleep behavior, sleep deprivation, and night shift, etc. It is also one of the most important symptoms of sleep disorders like obstructive sleep apnea (OSA). According to our survey on Korean literature, a few studies have dealt with daytime sleepiness, and we have not been able to locate any study comparing normal subjects with polysomnography-proven sleep disorder patients regarding daytime sleepiness. We aimed at comparing daytime sleepiness among normal healthy daytime workers, medical students being expected to have daytime sleepiness due to chronic sleep deprivation, and patients having sleep disorders diagnosed with polysomnography. We also studied the association between subjective daytime sleepiness and objective polysomnographic findings in patients with sleep disorders. Methods: One hundred three hospital workers, 137 medical students, and patients with sleep disorders were studied. Sleep disorders included OSA, periodic limb movements in sleep (PLMS), insomnia, and narcolepsy. The degree of subjective sleepiness in each group was measured by the Korean version of Epworth sleepiness scale and compared. The relationship between polysomnographic findings reflecting severity of sleep disorder in each patient group and subjective sleepiness was analyzed. As for patients with narcolepsy, the relationship between the mean sleep latency and subjective sleepiness was studied. Results: There was a significant difference of ESS score (F=68.190, dF=5.752, p<0.001) among daytime workers, medical students, and sleep disorder patients. In OSA patient group, the degree of the sleepiness had no significant correlation either with mean O2 satuaration (p=0.062) or with RDI (p=0.807). In PLMS patient group, there was no correlation between periodic limb movement index (PLMI) and subjective sleepiness (p=0.761). In narcolepsy patient group, the subjective sleepiness had no correlation with mean sleep latency measured with MSLT (p=0.055). Conclusion: We found a significant difference of subjective sleepiness among daytime workers, medical students, and patients with sleep disorders. However, no consistent correlation was found between severity of subjective sleepiness and objective polysomnographic findings reflecting severity of each sleep disorder. This research confirms that the evaluation of subjective sleepiness is important clinically, but it cannot substitute the objective measures such as nocturnal polysomnography and MSLT.

• Sleep Medicine and Psychophysiology
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• v.5 no.1
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• pp.103-110
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• 1998

Objectives : High co-morbidity of periodic limb movements during sleep(PLMS) and obstructive sleep apnea syndrome(OSAS) is well known and their incidences tend to increase in the elderly. Previous studies have inconsistently rep0l1ed increase or no change of periodic limb movement index(PLMI) by nasal continuous positive airway pressure(CPAP) in OSAS without analyzing possible variables affecting PLMI. We attempted to examine PLMI change evoked during CPAP titration and also factors affecting it in OSAS. Methods : Twenty-nine OSAS patients(M:F=26:3, mean age: $51.6{\pm}10.6\;yrs$) without other sleep disorders except for PLMS were selected, based on the nocturnal (baseline) polysomnograhy. Another night of noctumal polysomnography was performed for CPAP pressure titration. We compared between those two nights PLMI, mean and lowest $SaO_2$, and sleep variables. We also calculated PLMI differences between baseline and CPAP nights, named as delta PLMI (value of CPAP night PLMI minus value of baseline night PLMI). Correlations were calculated between delta PLMI and factors such as age, body mass index, applied CPAP pressure, baseline night values of respiratory disturbance index, mean and lowest $SaO_2$, and sleep parameter differences between baseline and CPAP nights. Results : Decrease of RDI(p<.01) and increase in mean and lowest $SaO_2$ (p<.05, p<.01) were observed during CPAP night. No sleep parameters showed significant change except for the decrease of total stage 1 sleep%(p<.01) during CPAP night. Ten out of 29 patients showed PLMI increase, while the other 19 patients showed either no change(n=14) or even PLMI decrease(n=5) during CPAP night. The 10 patients showing PLMI increase during CPAP night showed a significant positive correlation between delta PLMI and baseline night RDI(p<.05), which meant that PLMI increase was found to be more prominent in higher RDI patients than in lower RDI ones. There were no significant correlations between delta PLMI and other factors in the other 19 patients. Conclusions : We suggest that during the baseline night PLMS would have been underscored and/or masked due to the overlapping of PLMS and apneas/hypopneas or the arousals induced by apneas/hypopneas. Despite its still unknown mechanism, the CPAP application may unmask PLMS and increase PLMI in a subgroup of OSAS patients. It needs to be evaluated further whether the chronic CPAP use sustains the above finding.