• Sleep Medicine and Psychophysiology
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• v.3 no.1
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• pp.79-84
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• 1996

Kleine-Levin syndrome is a disorder characterized by recurrent episodes of hypersomnia, hyperphagia and hypersexuality that typically occur weeks or months apart. A 17-years-old male showed these episodes and took nocturnal polysomnography(NPSG) and multiple sleep latency test(MSLT). As results of NPSG, sleep latency was 82.5min, sleep efficiency was 82.5min, sleep efficiency was 82.5%, latency and percentage of REM sleep were 106.5min and 14.6% and percentage of slow wave sleep was 12.7%. In 4 times MLST, average of sleep latency and REM latency were 8min 7sec and 5min 20sec with 3 times sleep onset REM period(SOREMP). These findings are consistent with these of Keine-Levin syndrome. And the possible causes and classification of this syndrome were discussed.

• Safety and Health at Work
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• v.15 no.1
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• pp.53-58
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• 2024

Background: As social distancing persists and interest in work-life balance grows, more companies are adopting flexible work policies. While there have been studies on sleep disorders associated with different types of work, such as shift work, research exploring the relationship between flexible work schedules and sleep disorders is still limited, particularly among Korean workers. Methods: We performed a secondary analysis of the 6th Korean Working Conditions Survey, focusing on 31,243 paid workers out of a total of 50,538 participants. We defined flexible workers as those who set their own working hours. Sleep disorders were divided into three categories: 'difficulty falling asleep,' 'frequent waking during sleep,' and 'waking up feeling exhausted and fatigued.' Using scores derived from three specific symptoms, the Minimal Insomnia Symptoms Scale (MISS) was calculated to assess the prevalence of insomnia. We used chi-square tests to analyze demographic and job-related differences. A multivariate logistic regression analysis was employed to identify any relationship between flexible work schedules and sleep disorders. Results: Significant differences were found between flexible and non-flexible workers regarding age, income level, education level, and job type. Flexible workers reported sleep-related symptoms significantly more often. The odds ratio for insomnia was 1.40 (95% CI 1.21-1.61). For males, the odds ratio was 1.68 (1.36-2.08). Conclusion: This study establishes a correlation between flexible work schedules and sleep disorders among Korean salaried workers. Potential causes could include changes in circadian rhythm, increased work demands, and extended working hours. To precisely determine causality and associated diseases, further research is required.

• Sleep Medicine and Psychophysiology
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• v.6 no.2
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• pp.116-125
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• 1999

Objectives: The purpose of this study is to investigate the effect of exercise load on sleep structure and stress hormone secretion during sleep. Methods: Five male physical education students were included in this study after giving their written, informed consents in the Research Institute for Sports Science at the University of Hanyang. All subjects have performed for at least 3 years in a regular aerobic exercises such as football, basketball, and running. The subjects were divided into three groups ; NOE(non-exercise), MDE(middle duration exercise), LDE(long duration excercise). MDE group maintained a total of 120 min exercise, and LDE group maintained a total of 300 min exercise by football, basketball or badminton. All subjects were acclimatized to the experimental sleep condition by spending one night under expermental conditions, including the placement of an intravenous catheter. During the subsequent night(24:00-08:00), somnopolygraphic sleep recordings were obtained, and blood for measuring growth hormone, cortisol, testosterone, and $\beta$-endorphin was collected every 120 min throughout the night. Blood samples were obtained from prominent forearm veins of subjects. Then, the samples were immediately placed in ice and centrifuged within 10 min at 3000 rpm at $4^{\circ}C$. Statistical analyses were performed using the SPSS/$PC^+$. Data were analyzed by one-way ANOVA with repeated measures. Results: No significant differences among groups were observed in sleep latency, total sleep time, stage 2 sleep, and slow wave sleep. However, daytime exercise produced significant changes in stage 1 sleep, REM sleep, stage 2 sleep latency, REM sleep latency and sleep efficiency. Stage 1 sleep, stage 2 sleep latency, and REM sleep latency significantly increased in LDE compared to those of NOE and MDE groups. But the amount of REM sleep significantly decreased in LDE. Sleep efficiency of MDE was higher than those of NOE and LDE. The blood concentrations of growth hormone, testosterone, and cortisol during night sleep were significantly lower in LDE than in NOE. $\beta$-endorphin concentrations in blood during night sleep were not different among groups. Conclusion: The daytime exercise load was significantly related to sleep structure and stress hormone secretion during night sleep. Long duration exercise showed a harmful effect on sleep structure and hormone secretion. However, middle duration exercise had a beneficial effect on sleep structure and hormone secretion during sleep.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.19 no.3
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• pp.156-161
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• 2008

Objectives: The purpose of this study was to investigate the prevalence of sleep problems in Korean elementary school children and the differences in sleep problems elated to their school grade and gender. Methods : One public elementary school in Dae-gu, Korea as randomly selected. And, parents who agreed to participate this study were asked to complete a modified version of Tucson Children's Assessment of Sleep Apnea screening questionnaire (TuCASA). Results: The most common sleep problem was 'falling asleep in vehicle (44.2%)' and the prevalence rate of this problem differed by school grade. The prevalence rate of falling asleep while watching TV before 8 P.M. (8.0%), daytime fatigue (21.9%) and nocturnal enuresis during the past 6 months (5.3%) were significantly differed by school grade. The prevalence rate of falling asleep while doing home work, falling sleep during a lesson, snoring and bruxism were 12.6%, 1.0%, 26.7% and 13.2% respectively. Although these rates did not show any differences between grades, snoring as more in boys and daytime fatigue was more in girls. Conclusion: This study demonstrates that many elementary school children may have various sleep problems. Lower grade elementary schoolers had sleep problems which related to euro-developmental factors, whereas higher grade elementary schoolers had sleep problems related to sleep deprivation and stress. Finally, more female schooler showed signs of fatigue or sleepiness than male schoolers.

• Journal of Oral Medicine and Pain
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• v.40 no.2
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• pp.63-71
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• 2015

Purpose: To investigate the relationship between headache and sleep by evaluating sleep quality, daytime sleepiness, and specific features related to sleep-disordered breathing (SDB). Methods: One hundred one subjects with headache and 118 healthy controls were enrolled. To collect various information on headache attacks, headache group completed self-reported questionnaire about the characteristics of headache attacks and the migraine disability assessment (MIDAS) questionnaire. The subjective quality of sleep was evaluated in all of the subjects using the Pittsburgh sleep quality index (PSQI) and Epworth sleepiness scale (ESS). In addition, the following specific features of sleep were evaluated in 28 subjects selected randomly from each group: apnea-hypopnea index (AHI), prevalence of SDB, nocturnal oxygen saturation (SaO2), and oxygen desaturation index (ODI) as measured using a portable monitoring device. Results: The global PSQI and the prevalence of poor sleeping (global PSQI >5), ESS scores and the prevalence of daytime sleepiness (ESS score >10) were significantly higher in the headache group (both p<0.0001, respectively). The mean scores on the numerical rating scale and the MIDAS were significantly higher in the poor-sleeper group than in the good-sleeper group (p=0.0347 and p=0.0016, respectively). The global PQSI and prevalence of daytime sleepiness were significantly higher in the chronic-headache group than in the acute-headache group (p=0.0003 and p=0.0312, respectively). Conclusions: There is a significant association between headache and sleep. Especially, severity and chronicity of headache were significantly associated with sleep quality and daytime sleepiness.

• Safety and Health at Work
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• v.12 no.3
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• pp.311-316
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• 2021

Background: The present study investigated the association between two domains of physical activity (occupational physical activity [OPA] and leisure-time physical activity [LTPA]) and sleep duration. Methods: We investigated 3,421 paid workers from the Korea National Health and Nutrition Examination Survey, 2014-2015. Sleep duration was categorized into three categories (short for less than 5 h, optimal for 5-9 h, and long for more than 9 h). OPA and LTPA were defined in terms of answers to relevant questions. Odds ratios were calculated for sleep duration according to each physical activity domain using multinomial logistic regression models. Results: There were 464 subjects (13.6%) who showed short sleep duration, and 169 subjects (4.9%) who showed long sleep duration. Prevalence of OPA and LTPA was higher in male workers than in female workers (for OPA: 3.67% and 1.76%, respectively, p = 0.0108; for LTPA: 16.14% and 6.07%, respectively, p < 0.0001). The odds ratio of OPA for long sleep duration in female workers was 3.35 (95% confidence interval, 1.37-8.21). Otherwise, LTPA was not associated with sleep duration in female paid workers, nor both physical activity domains in male paid workers. Conclusion: Female paid workers with work-related physical activity were at risk of oversleeping. These findings also suggested that physical activity has distinct associations with sleep duration according to the physical activity domains and sex.

• Korean Journal of Psychosomatic Medicine
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• v.31 no.2
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• pp.173-175
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• 2023

Enuresis nocturia is more prevalent in children than in adults. Using polysomnography (PSG), we investigated the causes of adult enuresis nocturia in a 20-year-old female patient with nighttime bedwetting. In spite of normal urological examinations, her detailed medical history disclosed frequent sleep paralysis and urination during dreams. During PSG, two electromyograms were attached to her anus to assess the tone of her bladder's sphincter while she slept. During REM sleep, the EMG tone of the mandible decreased, but the anal and bladder sphincter tones did not. The polysomnogram revealed moderate obstructive sleep apnea. Consequently, she was diagnosed with adult parasomnia (nocturnal enuresis) overlap syndrome with OSA. This study demonstrates the value of PSG with simultaneous anal tone EMG for diagnosing NREM parasomnia and nocturnal enuresis.

• Journal of Korean Neurosurgical Society
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• v.61 no.5
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• pp.600-607
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• 2018

Objective : It has been reported in recent studies that 50-80% of patients with cervical disc hernia have concomitant sleep disorders. The aim of this study was to evaluate the quality of sleep before and after surgical treatment in patients with cervical disc hernia and to assess the effects on treatment. Methods : The study included 32 patients performed discectomy and fusion with an intervertebral cage through the right anterior cervical approach. Oswestry Disability Index (ODI), Visual Analog Scale (VAS) and Pittsburgh Sleep Quality Index (PSQI) were applied to all patients preoperatively and at one month postoperatively. Results : The postoperative PSQI total points and all the PSQI subscale points, the ODI and VAS scores were significantly reduced compared to the preoperative values. A positive correlation was determined between the preoperative ODI points and the PSQI total points and sleep duration, sleep latency and daytime functional loss subscale points. A positive correlation was also found between preoperative ODI points and VAS points. A positive correlation was determined between the preoperative VAS points and and the PSQI total points and sleep duration, and sleep latency subscale points. A negative correlation was determined between the postoperative ODI and the daytime functional loss subscale points. Conclusion : The results of the study showed that in patients with cervical disc hernia, sleep quality and daytime functionality were negatively affected by severity of pain that limited daily activities. Bringing the pain under control with surgical treatment was observed to increase sleep quality. It can be concluded that when planning treatment for these patients, it should be taken into consideration that there could be a sleep disorder in addition to the complaints and symptoms such as pain, hypoestesia and loss of strength.

• Journal of Preventive Medicine and Public Health
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• v.47 no.3
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• pp.150-157
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• 2014

Objectives: The decrease or increase in sleep duration has recently been recognized as a risk factor for several diseases, including hypertension and obesity. Many studies have explored the relationship of decreased sleep durations and injuries, but few have examined the relationship between increased sleep duration and injury. The objective of this research is to identify the risk for injury associated with both decreased and increased sleep durations. Methods: Data from the 2010 Community Health Survey were used in this study. We conducted logistic regression with average sleep duration as the independent variable, injury as a dependent variable, and controlling for age, sex, occupation, education, region (cities and provinces), smoking, alcohol use, body mass index, hypertension, diabetes, arthritis, and depression. Seven categories of sleep duration were established: ${\leq}4$, 5, 6, 7, 8, 9, and ${\geq}10$ hours. Results: Using 7 hours of sleep as the reference, the adjusted injury risk (odds ratio) for those sleeping a total of ${\leq}4$ h/d was 1.53; 1.28 for 5 hours, for 1.11 for 6 hours, 0.98 for 8 hours, 1.12 for 9 hours, and 1.48 for ${\geq}10$ hours. The difference in risk was statistically significant for each category except for the 8 and 9 hours. In this study, risk increased as the sleep duration decreased or increased, except for the 8 and 9 hours. Conclusions: This research found that either a decrease or increase in sleep duration was associated with an increased risk for injury. The concept of proper sleep duration can be evaluated by its associated injury risk.

• Journal of Society of Preventive Korean Medicine
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• v.27 no.1
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• pp.89-98
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• 2023

Objectives : This study collected sleep information by wearable device in the Korean medicine Daejeon citizen cohort (KDCC). It was measured based on the sleep record information measured by wearing a Fitbit, and the possibility of clinical use was examined for compliance with objective sleep collection. Based on compliance, the possibility of clinical use was examined. Methods : After surveying personal information and PSQI(Pittsburgh Sleep Quality Index), sleep information was collected by Fitbit for 14 days. Compliance was measured based on sleep record information by Fitbit. Compliance was analyzed by sex, age, BMI(Body Mass Index), and sleep group(deep/poor). Results : The number of participants was 730, and the compliance was 94.3%, and the compliance group was 675(92.5%). The age of the participants varied from 30 to 60 years old, and the average age was 46±6.7 years. There were 218 males and 512 females. Young people have high compliance. Males are more compliance than females. As the BMI score decreased in the 30s, the compliance was higher. The underweight group in all age groups had 100 compliance. The underweight group was all female. The low compliance groups were that 30 years males (obesity level2), 50 years females (overweight group), and 50 years females (obesity level2). There was no significant difference in compliance between deep sleep group and poor sleep group. In deep sleep group, females showed higher compliance. In poor sleep group, males showed higher compliance. The average duration of Fitbit usage among participants was 20.1 days. The compliant group wore the device for an average of 21.3 days, while the non-compliant group wore it for only 5.2 days. Of the compliant group, 86.9% (73.8% of all participants) continued to wear the Fitbit after the recommended 14-day period, and 50.8% wore it for more than 20 days. Conclusions : This study showed the possibility of adaptation for wearing a Fitbit for collecting objective sleep information. It is judged that the compliance is high because it was worn for more than 13.2 days out of the 14 days required. It is considered meaningful because the compliance was measured based on the sleep information by Fitbit, not the questionnaire. As the data on objective sleep time is collected automatically, we believe that the burden on participants after the study period is not significant for a certain period. Compliance may be even higher for cohorts related to illnesses and with doctor's orders, rather than for the general population.