• Natural Product Sciences
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• v.19 no.2
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• pp.179-185
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• 2013

Polygalae radix (PR) has traditionally been used as a sedative and anti-stress agent in oriental countries for a long time. PR which contains many ingredients is especially rich in saponins. This study was performed to investigate whether ethanol extract of PR enhances pentobarbital-induced sleep behaviors. In addition, possible mechanisms also were investigated. PR inhibited locomotor activity in mice. PR increased sleep rate and sleep time by concomitant administration with sub-hypnotic dose of pentobarbital (28 mg/kg). PR prolonged total sleeping time, and shortened sleep latency induced by pentobarbital (42 mg/kg). In addition, PR increased intracellular chloride concentration in primary cultured neuronal cells. The expression level of glutamic acid decarboxylase (GAD) were increased, and ${\gamma}$-aminobutyric acid $(GABA)_A$ receptors subunits were modulated by PR, especially increasing ${\gamma}$-subunit expression. In conclusion, PR augments penobarbital-induced sleep behaviors through activation of $GABA_A$ receptors and chloride channel complex.

• Journal of Rhinology
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• v.25 no.2
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• pp.69-74
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• 2018

Background and Objectives: Sleep disturbances and excessive daytime sleepiness (EDS) are the major symptoms of obstructive sleep apnea (OSA). This study aimed to investigate clinical implications of insomnia and EDS in patients with OSA using the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS). Materials and Method: We evaluated 131 subjects with suspected OSA who were undergoing polysomnography (PSG) and performing the PSQI and ESS surveys. OSA was diagnosed when the apnea-hypopnea index was five or more. EDS was defined when ESS score was 11 points or higher. Detailed history and questionnaire were used to categorize insomnia. We compared clinical variables and PSG results in subgroups with or without insomnia and EDS. Results: There were no significant differences of PSQI and ESS score between controls and OSA. OSA with insomnia had significantly increased total score (p<0.001) and decreased total sleep time (p=0.001) and sleep efficiency (p=0.001) on the PSQI compared to those without insomnia. OSA with EDS showed significantly increased PSQI score (p=0.022) and decreased total sleep time (p=0.018) on PSG compared to those without EDS. Neither PSQI nor ESS score had a correlation with respiratory variables such as AHI and oxygen saturation. Total sleep time had a significant effect on both insomnia and EDS in patients with OSA. Conclusion: Decreased total sleep time had important effects on subjective symptoms of OSA and comorbid insomnia. Therefore, restoration of decreased sleep time is important in the management of OSA.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.5
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• pp.404-409
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• 2005

This study is to investigate effects of thermal conditions on sleep. Five female university students participated in the sleep experiment. Three temperature levels (22, 26, and $30^{\circ}C$) were given, and relative humidity was maintained to $50\%$. When as subject arrived in the chamber at 9 o'clock in the evening, questionnaire was given to check physical and psychological conditions. After checking conditions, subjects went to bed till 07 : 30 in the morning. Body movement was checked during sleeping. After sleep in the chamber, questionnaire was given to the subject in order to check sleep quality. Subjects evaluated sleep quality by themselves by answering the time they fall asleep and wake up, frequency of wake during sleep, causes of each waking, and feeling after sleep. Sleep quality was rated with 7-point scale. At $30^{\circ}C$ condition, body movement was significantly higher than of other thermal conditions. The best sleep quality was obtained at the $26^{\circ}C$ condition, while the worst sleep was taken at the $30^{\circ}C$ condition.

• Anxiety and mood
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• v.12 no.1
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• pp.21-27
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• 2016

Objective : The aim of this study was to investigate the relationship between subjective sleep problems and various types of traumatic events of patients with depressive disorder. Methods : A total of 411 patients diagnosed with depressive disorders were recruited in this study. The participants filled out Life Time Events Checklist (LEC), Pittsburgh Sleep Quality Index (PSQI), Beck Depression Inventory (BDI), and State-Trait Anxiety Inventory (STAI). We used the independent t-test and analysis of covariance to compare each component of PSQI between depressive patients with and without traumatic experiences. Results : The groups of patients who experienced a serious accident at work, home or during recreational activity, sexual assault, other unwanted or uncomfortable sexual experience, life-threatening illness or injury, and sudden, unexpected death of a near and dear one showed lower scores in a few components of PSQI. Sleep disturbance was a common problem in all five groups. Lower subjective sleep quality and longer sleep latency was observed in three groups. There were no differences in the other components of PSQI among groups. Conclusion : This study showed that various types of traumatic events may have different effects on subjective sleep quality as a consequence of the traumatic event which they had experienced.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.1
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• pp.41-51
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• 2017

This Paper Describes a Method for the Evaluation of Sleep Apnea, Namely, the Peak Signal-to-noise ratio (PSNR) of Wavelet Transformed Electroencephalography (EEG) Data. The Purpose of this Study was to Investigate EEG Properties with Regard to Differences between Sleep Spindles and K-complexes and to Characterize Obstructive Sleep Apnea According to Sleep Stage. We Examined Non-REM and REM Sleep in 20 Patients with OSA and Established a New Approach for Detecting Sleep Apnea Base on EEG Frequency Changes According to Sleep Stage During Sleep Apnea Events. For Frequency Bands Corresponding to A3 Decomposition with a Sampling Applied to the KC and the Sleep Spindle Signal. In this Paper, the KC and Sleep Spindle are Ccalculated using MSE and PSNR for 4 Types of Mother Wavelets. Wavelet Transform Coefficients Were Obtained Around Sleep Spindles in Order to Identify the Frequency Information that Changed During Obstructive Sleep Apnea. We also Investigated Whether Quantification Analysis of EEG During Sleep Apnea is Valuable for Analyzing Sleep Spindles and The K-complexes in Patients. First, Decomposition of the EEG Signal from Feature Data was Carried out using 4 Different Types of Wavelets, Namely, Daubechies 3, Symlet 4, Biorthogonal 2.8, and Coiflet 3. We Compared the PSNR Accuracy for Each Wavelet Function and Found that Mother Wavelets Daubechies 3 and Biorthogonal 2.8 Surpassed the other Wavelet Functions in Performance. We have Attempted to Improve the Computing Efficiency as it Selects the most Suitable Wavelet Function that can be used for Sleep Spindle, K-complex Signal Processing Efficiently and Accurate Decision with Lesser Computational Time.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.4
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• pp.307-312
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• 2007

This study was performed to evaluate sleep efficiencies and conditions for comfortable sleep based on the analysis of sleep efficiency and MST under four thermals conditions ($22^{\circ}C,\;24^{\circ}C,\;26^{\circ}C,\;30^{\circ}C$). Five female subjects who have similar life cycle and sleep patterns were participated for the sleep experiment. Their age was from 20 to 22 years old. They were healthy, and had regular sleep with consistent bed and wakeup time. It was checked whether they had a good sleep before the night of experiment. Experiments were performed in an environmental chamber using thermo-hygrostat. The physiological signal (EEG) for sleep stage were obtained from C3-A2 and C4-Al electrode sites. Sleep stages were classified, then SWS latency and SWS/TST were calculated for the evaluation for sleep efficiencies on thermal conditions. As results, mean skin temperature for comfort sleeping was $34.5{\sim}35.4^{\circ}C$. Considering sleep efficiency and mean skin temperature, indoor room temperature of upper limit was $28.1^{\circ}C$.

• Sleep Medicine and Psychophysiology
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• v.4 no.1
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• pp.89-95
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• 1997

The authors studied 5 cases of idiopathic CNS hypersomnia who visited Division of Sleep Studies, Seoul National University Hospital in 1995. Detailed medical history was taken and nocturnal polysomnography(NPSG), multiple sleep latency test(MSLT) and human leukocyte antigen(HLA) typing were performed. Neither cataplexy nor hypnagogic hallucination was reported in all cases and in NPSGs, there were tendencies of increased sleep period time and decreased slow wave sleep time. In MSLT, all the subjects showed average sleep latencies less than 8 minutes without sleep-onset rapid eye movement period(SOREMP). In HLA typing, some correlation between idiopathic CNS hypersomnia and HLA DR4 was observed. In contrast to previous reports, overall treatment response with methylphenidate was remarkable. Therefore, the authors suggest that patients suspected of idiopathic CNS hypersomnia be actively evaluated and treated with rather optimistic perspective.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2007.11a
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• pp.195-203
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• 2007

In this paper, an analytic model of sleep model operation in the IEEE 802.16e is investigated. A mobile subscribe. station (MSS) goes to sleep mode after negotiations with the base station (BS) and wakes up periodically for a short interval to check whether there is downlink traffic to it. If the arrival of traffic is notified, an MSS returns to wake mode. Otherwise, it again enters increased sleep interval which is double as the previous one. In order to consider the situation more practically, we propose the sleep mode starting threshold, during which MSS should await packets before it enters the sleep mode. By modifying the M/G/1 with multiple vacations model, energy consumption ratio(ECR) and average packet response time are calculated. Our analytic model provides potential guidance in determining the optimal parameters values such as sleep mode starting threshold, minimal sleep and maximal sleep window.

• Sleep Medicine and Psychophysiology
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• v.18 no.2
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• pp.72-75
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• 2011

Sleep disorders such as insomnia, obstructive sleep apnea (OSA), and restless legs syndrome (RLS) are very common disorders and may cause significant burden in terms of individual as well as societal aspects. Sleep insufficiency from such sleep disorders may cause deleterious effects on daily work life and may be associated with other major medical or psychiatric disorders including cardiovascular disease, diabetes mellitus, depression, and anxiety disorder. Various motor or occupational accident may result from the sleep problems. In addition, recent researches provide the method to evaluate the lost productivity time in terms of absenteeism and presenteeism. Moreover, several studies on cost-effectiveness of treatment of sleep disorders show that it is cost-effective.

• Sleep Medicine and Psychophysiology
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• v.16 no.1
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• pp.5-9
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• 2009

Relatively little is known about the neurobiology of insomnia, despite its wide prevalence and broad medical impact. Although much is still to be learned about the pathophysiology of the disorder, identification, systematic assessment, and appropriate treatment are clearly beneficial to patients. Recent research, using quantitative EEG, polysomnography (PSG), multiple sleep latency test (MSLT) and neuroimaging techniques, suggests that some broad areas can be identified as possible pathophysiological models. Sleep-wake homeostat model hypothesizes a failure in homeostatic regulation of sleep, an attenuated increase in sleep drive with time awake, and/or defective sensing of sleep need. Circadian clock model hypothesizes a dysfunctional circadian clock, resulting in changes in the timing of sleep-wake propensity that are incompatible with normal sleep. Intrinsic sleep-wake state mechanism model suggests that abnormal function of insomnia comprises the systems responsible for expression of the sleep states themselves. Extrinsic over-ride mechanism (stress-response) model suggests that insomnia reflects the consequences of overactivity of one of the systems considered "extrinsic" to normal sleep-wake control. Many current therapies for insomnia are based on these physiological models. Several attempts have been made to create a physiological model that would explain this disorder and could be used as a foundation for treatment. However, it appeared that no model can fully explain and clarify all aspects of insomnia. Future research should be necessary to expand our knowledge on the biological dimensions of insomnia.