• Journal of the Korean Society of Safety
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• v.30 no.2
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• pp.56-62
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• 2015

The purpose of this study was to identify the relationship between the index of Electrocardiography(LF/HF) and the occurrence of drowsiness driving while driving in a simulated situation. Participants were 31 undergraduate students with an experience in driving and they participated 30 minutes driving under enough sleep condition and 1 hour under the sleep deprivation condition. The Euro Truck Simulator II was used for driving simulation task and ECG and perceived drowsiness of each participants were measured during two driving conditions. Perceived sleepiness recorded by the checklist every 10 minutes and ECG data extracted before and after 15 seconds of every 10 minutes to verify the relationship between two variables. The results showed that the level of perceived sleepiness under sleep deprivation condition was higher than that under the enough sleep condition, and the level of LF/HF under sleep deprivation condition was lower than that under the enough sleep condition. In addition, the result of analysis of repeated measure ANOVA for ECG indicated that authentic sleepiness revealed in 20 minutes after the start of driving under the sleep deprivation condition. However, the result of perceived drowsiness indicated that authentic sleepiness revealed in 30 minutes after the start of driving. These result suggest that the time difference between biological and perceived response on drowsiness may be exist. Finally, the significant negative correlation between the LF/HF level and perceived drowsiness was observed. These findings suggest that ECG(LF/HF) can be an possible index to measure drowsiness driving.

• The Journal of Pediatrics of Korean Medicine
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• v.24 no.3
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• pp.106-120
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• 2010

Objectives: Sanjointang has been clinically used much for treating sleeplessness. However, the effects of Sanjointang in artificial sleep deprivation situations are not known. The purpose of this study is to evaluate the heart rate, left ventricular systolic pressure, left ventricular diastolic pressure, +dp/dt maximum, -dp/dt maximum, and -dp/dt / +dp/dt ratio which are related to the hemodynamic functions of the heart by using sleep-deprived Sparague-Dawley rats, in order to clarify the impact of Sanjointang on hemodynamic functions of the heart of sleep deprived rats. Methods: Eighteen hearts were removed from the male Sparague-Dawley rats weighting about 180g were perfused by the Langendorff technique with modified 37 Krebs-Henseleit's buffer solution at a constant perfusion pressure (60mmHg). They were randomly assigned to one of the following three groups, 1) Normal group (those which did not have sleep deprivation and received normal saline administration), 2) Control group (sleep deprived and normal saline administered), 3) Sample group (sleep deprived and Sanjointang was administered). Control and sample groups rats were deprived 96 hours of sleep by using the modified multiple platform technique. Heart rate, left ventricular systolic pressure, left ventricular diastolic pressure, +dp/dt maximum, -dp/dt maximum, -dp/dt / +dp/dt ratio were evaluated at baseline after the administration of either normal saline or Sanjointang. Results: The heart rate and -dp/dt / +dp/dt ratio was significantly decreased in rats with 96 hours of sleep deprived significantly decreased. The change in the heart rate after administering Sanjointang did not show any significant difference. The left ventricular systolic pressure of the removed heart significantly decreased due to Sanjointang administration, while the left ventricular diastolic pressure significantly increased (p<0.05). The +dp/dt maximum and -dp/dt maximum both significantly decreased in the removed heart after administering Sanjointang. (p<0.05). There was no significant difference observed in the -dp/dt / +dp/dt ratio after administering Sanjointang. Conclusions: According to the results above, sleep deprivation significantly decreases heart rate and -dp/dt / +dp/dt ratio. This is considered as a result of exhaustion due to accumulation of fatigue. Meanwhile, Sanjointang reduced left ventricular systolic pressure and raised left ventricular diastolic pressure, and relieved the contractility and relaxation of the myocardium. Consequently, this reduces the burden of the heart and creates a relatively stabilized heart condition similar to a sleeping condition.

• The Korean Journal of Physiology and Pharmacology
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• v.26 no.6
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• pp.415-425
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• 2022

Memory formation in the hippocampus is formed and maintained by circadian clock genes during sleep. Sleep deprivation (SD) can lead to memory impairment and neuroinflammation, and there remains no effective pharmacological treatment for these effects. Myricetin (MYR) is a common natural flavonoid that has various pharmacological activities. In this study, we investigated the effects of MYR on memory impairment, neuroinflammation, and neurotrophic factors in sleep-deprived rats. We analyzed SD-induced cognitive and spatial memory, as well as pro-inflammatory cytokine levels during SD. SD model rats were intraperitoneally injected with 10 and 20 mg/kg/day MYR for 14 days. MYR administration significantly ameliorated SD-induced cognitive and spatial memory deficits; it also attenuated the SD-induced inflammatory response associated with nuclear factor kappa B activation in the hippocampus. In addition, MYR enhanced the mRNA expression of brain-derived neurotropic factor (BDNF) in the hippocampus. Our results showed that MYR improved memory impairment by means of anti-inflammatory activity and appropriate regulation of BDNF expression. Our findings suggest that MYR is a potential functional ingredient that protects cognitive function from SD.

• Clinical and Experimental Pediatrics
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• v.54 no.1
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• pp.29-35
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• 2011

Purpose: Korean adolescents have severe nighttime sleep deprivation and daytime sleepiness because of their competitive educational environment. However, daytime sleep patterns and sleepiness have never been studied using age-specific methods, such as the pediatric daytime sleepiness scale (PDSS). We surveyed the daytime sleepiness of Korean adolescents using a Korean translation of the PDSS. Methods: We distributed the 27-item questionnaire, including the PDSS and questions related to sleep pattern, sleep satisfaction, and emotional state, to 3,370 students in grades 5-12. Results: The amount of nighttime sleep decreased significantly with increasing age. During weekday nights, $5-6^{th}$ graders slept for $7.95{\pm}1.05h$, $7-9^{th}$ graders for $7.57{\pm}1.05h$, and $10-12^{th}$ graders for $5.78{\pm}1.13h$. However, the total amounts of combined daytime and nighttime sleep during weekdays were somewhat greater, $8.15{\pm}1.12h$ for $5-6^{th}$ graders, $8.17{\pm}1.20h$ for $7-9^{th}$ graders, and $6.87{\pm}1.40h$ for $10-12^{th}$ graders. PDSS scores increased with age, $11.89{\pm}5.56$ for $5-6^{th}$ graders, $16.57{\pm}5.57$ for $7-9^{th}$ graders, and $17.71{\pm}5.24$ for $10-12^{th}$ graders. Higher PDSS scores were positively correlated with poor school performance and emotional instability. Conclusion: Korean teenagers sleep to an unusual extent during the day because of nighttime sleep deprivation. This negatively affects school performance and emotional stability. A Korean translation of the PDSS was effective in evaluating the severity of daytime sleepiness and assessing the emotional state and school performance of Korean teenagers.

• Sleep Medicine and Psychophysiology
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• v.8 no.2
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• pp.129-137
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• 2001

Objectives: The purpose of this study is to investigate the effects of 38-hour sleep deprivation on fine motor performance. The Motor Performance Series (MPS) in the Vienna Test System (computerized neurocognitive function tests) was used in this study. Methods: Twenty four subjects participated in this study. Subjects had no past history of psychiatric disorders and physical illness. Subjects had normal sleep-waking cycle without current sleep disturbances and were all right-handed (Annett's Hand Preference Questionnaire: above +9 points). To minimize the learning effects, familiarization with the Vienna Test System was performed one day before the study. Subjects were to get up at 6:00 in the morning after getting enough sleep according to his or her usual sleep-wake cycle. After awakening, subjects remained awake for 38 hours under continuous surveillance. During two consecutive study days, the subjects tested MPS at 7 AM and 7 PM each day, which means the MPS was done four times in total. During the experiment, anything that could affect the subjects' sleep such as coffee, tea, alcohol, a nap, tiring sports, and all medications were prohibited. Results: In MPS, the fine motor functions of both hands decreased after 38 hours of sleep deprivation. The decrement in motor performance was prominent in the dominant right hand. In the right hand, the total number of tapping was reduced (p<.005), and the number of misses (p<.05) and the length of misses (p<.05) of line tracking, the total length of inserting a short pin (p<.01), the total length of inserting a long pin (p<.05), and the number of misses in aiming (p<.05) increased. Such performance decrement was distinct in the morning sessions. Conclusions: These results suggest that fine motor performance decrement during sleep deprivation is predominant in the right hand, which exerts maximal motor function. The finding of decrement in motor function in tapping during sleep deprivation also suggested that the time required for exhaustion of muscles is shortened during sleep deprivation. More deterioration of motor performance was shown in the morning, which could be explained as circadian rhythm effects.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.2
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• pp.43-49
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• 2010

Autonomic nervous system (ANS) acts as a control system functioning largely below the level of consciousness, and controls visceral functions. The activity of the ANS has been assessed by means of the heart rate variability (HRV). It has been reported that HRV is dependent on sex, age, body mass index, and smoking, etc. However, the effects of posture and sleep deprivation on HRV have rarely been reported. Objective of our work was to find out which posture is appropriate for stable HRV. We measured the number of sleep deprivation and HRV using power spectrum in six stages for 30 minutes. Increased low frequency (LF) power and high frequency (HF) power indicate enhanced sympathetic and parasympathetic activity, respectively. We determined the LF/HF ratio to minimize individual difference. It was found that sleep deprivation by awakening up subjects was affected by posture, which resulted in changes of LF/HF. Although LF/HF varied with time, it was more stable in sitting than in supine. In conclusion, we recommend sitting posture when measuring HRV because of less sleep deprivation resulting in less variation in LF/HF.

• Journal of Korean Academy of Nursing
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• v.54 no.2
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• pp.139-150
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• 2024

Purpose: This study aimed to identify changes in sleep patterns and fatigue levels during consecutive night shifts among shift nurses and to determine the association between sleep parameters and increased fatigue levels during work. Methods: This prospective observational study employing ecological momentary assessments was conducted using data collected from 98 shift nurses working in Korean hospitals between June 2019 and February 2021. The sleep patterns were recorded using actigraphy. The participants reported their fatigue levels at the beginning and end of each night shift in real time via a mobile link. Linear mixed models were used for the analysis. Results: Nurses spent significantly less time in bed and had shorter sleep durations during consecutive night shifts than on off-duty days, whereas their wake times after sleep onset were much longer on off-duty days than on on-duty days. Fatigue levels were higher on the second and third night-shift days than on the first night-shift days. A shorter time spent in bed and asleep was associated with a greater increase in fatigue levels at the end of the shift than at the beginning. Conclusion: Nurses experience significant sleep deprivation during consecutive night shifts compared with off-duty days, and this sleep shortage is associated with a considerable increase in fatigue levels at the end of shifts. Nurse managers and administrators must ensure sufficient intershift recovery time during consecutive night shifts to increase the time spent in bed and sleeping.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.5
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• pp.291-297
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• 2010

The sleep homeostatic response significantly affects the state of anesthesia. In addition, sleep recovery may occur during anesthesia, either via a natural sleep-like process to occur or via a direct restorative effect. Little is known about the effects of isoflurane anesthesia on sleep homeostasis. We investigated whether 1) isoflurane anesthesia could provide a sleep-like process, and 2) the depth of anesthesia could differently affect the post-anesthesia sleep response. Nine rats were treated for 2 hours with $ad$ $libitum$ sleep (Control), sleep deprivation (SD), and isoflurane anesthesia with delta-wave- predominant state (ISO-1) or burst suppression pattern-predominant state (ISO-2) with at least a 1-week interval. Electroencephalogram and electromyogram were recorded and sleep-wake architecture was evaluated for 4 hours after each treatment. In the post-treatment period, the duration of transition to slow-wave-sleep decreased but slow wave sleep (SWS) increased in the SD group, but no sleep stages were significantly changed in ISO-1 and ISO-2 groups compared to Control. Different levels of anesthesia did not significantly affect the post-anesthesia sleep responses, but the deep level of anesthesia significantly delayed the latency to sleep compared to Control. The present results indicate that a natural sleep-like process likely occurs during isoflurane anesthesia and that the post-anesthesia sleep response occurs irrespective to the level of anesthesia.

• The Korean Journal of Physiology and Pharmacology
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• v.26 no.5
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• pp.297-305
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• 2022

The presence of artificial light enables humans to be active 24 h a day. Many people across the globe live in a social culture that encourages staying up late to meet the demands of various activities, such as work and school. Sleep deprivation (SD) is a severe health problem in modern society. Meanwhile, as with cardiometabolic disease, there was an obvious tendency that coronary heart disease (CHD) to become a global epidemic chronic disease. Specifically, SD can significantly increase the morbidity and mortality of CHD. However, the underlying mechanisms responsible for the effects of SD on CHD are multilayered and complex. Inflammatory response, lipid metabolism, oxidative stress, and endothelial function all contribute to cardiovascular lesions. In this review, the effects of SD on CHD development are summarized, and SD-related pathogenesis of coronary artery lesions is discussed. In general, early assessment of SD played a vital role in preventing the harmful consequences of CHD.

• Sleep Medicine and Psychophysiology
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• v.5 no.1
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• pp.18-33
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• 1998

Sleep and Epilepsy either represent the opposite and independent spectrum of episodic manifestations from brain or closely interact with each other. Sleep or sleep deprivation may provoke epileptic seizures or activate epileptiform discharges in epilepsy patients whereas epilepsy may alter the sleep structure. Sleep stages are also known to influence pathophysiology of seizures in terms of ictogenesis. In this review, the impact of sleep on epilepsy as well as that of epilepsy on sleep are presented. Additionally the interaction between sleep and epilepsy will be discussed. This review will also comment on the differential diagnosis between nocturnal or sleep-related epilepsy and various sleep disorders. Finally, clinical application of the above perspectives of sleep and epilepsy will be suggested for the purpose of a better management of epilepsies.