• Sleep Medicine and Psychophysiology
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• v.13 no.1
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• pp.15-21
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• 2006

Introduction: The objective of the present study was to investigate bedtime, rise time and time-in-bed of Korean college students, separately on weekday and on weekend and to compare them. In addition, this study also aimed to evaluate the influence of gender, age and grade on the above sleep parmeters in Korean college students. Methods: Information regarding bedtime and rise time, separately on weekday and on weekend, of Korean college students were obtained by self-administered questionnaire. Questionnaires of 1,825 students (1,416 females and 409 males, age 18-30；mean age $21.1{\pm}2.2$) were used for statistical analyses. Results: Korean college students retired to bed 50 minutes later (00：49 on weekday；01：40 on weekend；t=39.67, p<0.001), rose 1 hour 58 minutes later (07：52 on weekday；09：50 on weekend；t=39.46, p<0.001), and slept 1 hour 8 minutes longer (t=13.33, p<0.001) on weekend. Compared to male students, female students had earlier rise time (t=8.96, p<0.01；t=3.89, p<0.01) and earlier bedtime both on weekday and weekend (t=7.10, p<0.01；t=6.04, p<0.01), and shorter time-in-bed on weekday (t=1.99, p<0.01). In addition, rise time delay and time-in-bed increase on weekend were more prominent in female students than in male students (t=3.41, p<0.01; t=3.68, p<0.01). Grade was correlated with bedtime and rise time on weekday (${\beta}=0.1022$, p<0.01；${\beta}=0.1009$, p<0.01), bedtime and time-in-bed on weekend (${\beta}=0.1096$, p<0.01；${\beta}=-0.0990$, p<0.01), and differences between week-day and weekend of the rise time and the time-in-bed (${\beta}=-0.0906$, p<0.01；${\beta}=-0.1115$, p=0.02). Conclusions: In this study, Korean college students had earlier bedtime/rise time and shorter time-in-bed on weekday than on weekend. These findings suggest that weekday sleep-wake schedule of Korean college students may be advanced relative to their biological sleep-wake cycle and that this discrepancy may be associated with weekday sleep deprivation. In addition, differences of sleep patterns between weekday and weekend were more prominent in female students and students with lower grade. Therefore, discrepancy between weekday sleep-wake schedule and biological sleep-wake cycle, as well as weekday sleep deprivation, might be more serious in female or lower-grade students.

• Journal of Biomedical Engineering Research
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• v.25 no.1
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• pp.11-19
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• 2004

Stage 1 sleep provides important information regarding interpretation of nocturnal polysomnography, particularly sleep onset. It is a short transition period from wakeful consciousness to sleep. Lack of prominent sleep events characterizing stage 1 sleep is a major obstacle in automatic sleep stage scoring. In this study, we attempted to utilize simultaneous EEC and EOG processing and analyses to detect stage 1 sleep automatically. Relative powers of the alpha waves and the theta waves were calculated from spectral estimation. Either the relative power of alpha waves less than 50％ or the relative power of theta waves more than 23％ was regarded as stage 1 sleep. SEM (slow eye movement) was defined as the duration of both eye movement ranging from 1.5 to 4 seconds and regarded also as stage 1 sleep. If one of these three criteria was met, the epoch was regarded as stage 1 sleep. Results f ere compared to the manual rating results done by two polysomnography experts. Total of 169 epochs was analyzed. Agreement rate for stage 1 sleep between automatic detection and manual scoring was 79.3％ and Cohen's Kappa was 0.586 (p＜0.01). A significant portion (32％) of automatically detected stage 1 sleep included SEM. Generally, digitally-scored sleep s1aging shows the accuracy up to 70％. Considering potential difficulties in stage 1 sleep scoring, the accuracy of 79.3％ in this study seems to be robust enough. Simultaneous analysis of EOG provides differential value to the present study from previous oneswhich mainly depended on EEG analysis. The issue of close relationship between SEM and stage 1 sleep raised by Kinnariet at. remains to be a valid one in this study.

• Sleep Medicine and Psychophysiology
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• v.22 no.2
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• pp.70-76
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• 2015

Background and Objectives: Insomnia is the most prevalent sleep disorder in the general population and is considered to be a disorder of hyperarousal. The aim of this study was to measure the psychophysiological responses in insomnia patients using a biofeedback system, and to compare them with results from normal healthy subjects. Materials and Methods: Eighty patients with primary insomnia (35 males and 45 females, average age $49.71{\pm}12.91years$) and 101 normal healthy controls (64 males and 37 females, average age $27.65{\pm}2.77$) participated in this study. Electromyography (EMG), heart rate (HR), skin conductance (SC), skin temperature (ST), and respiratory rate (RR) were recorded using a biofeedback system during 5 phases (baseline, stress 1, recovery 1, stress 2, recovery 2) of a stress reactivity test, and average values were calculated. Difference in values between the two groups in each corresponding phase was analyzed with independent t-test, and change in values across phases of the stress reactivity test was analyzed with paired t-test (all two-tailed, p<0.05). Results: Compared to normal controls, insomnia patients had higher EMG in all 5 phases (baseline : $7.72{\pm}3.88{\mu}V$ vs. $4.89{\pm}1.73{\mu}V$, t = -6.06, p<0.001 ; stress 1 : $10.29{\pm}5.16{\mu}V$ vs. $6.63{\pm}2.48{\mu}V$, t = -5.84, p<0.001 ; recovery 1 : $7.87{\pm}3.86{\mu}V$ vs. $5.17{\pm}2.17{\mu}V$, t = -5.61, p<0.001 ; stress 2 : $10.22{\pm}6.07{\mu}V$ vs. $6.98{\pm}2.98{\mu}V$, t = -4.37, p<0.001 ; recovery 2 : $7.88{\pm}4.25{\mu}V$ vs. $5.17{\pm}1.99{\mu}V$, t = -5.27, p<0.001). Change in heart rate across phases of the stress reactivity test were higher in normal controls than in insomnia patients (stress 1-baseline : $6.48{\pm}0.59$ vs. $3.77{\pm}0.59$, t = 3.22, p = 0.002 ; recovery 1- stress 1 : $-5.36{\pm}0.0.59$ vs. $-3.16{\pm}0.47$, t = 2.91, p = 0.004 ; stress 2-recovery 1 : $8.45{\pm}0.61$ vs. $4.03{\pm}0.47$, t = 5.72, p<0.001 ; recovery 2-stress 2 : $-8.56{\pm}0.65$ vs. $4.02{\pm}0.51$, t = -5.31, p<0.001). Conclusion: Psychophysiological profiles of insomnia patients in a stress reactivity test were different from those of normal healthy controls. These results suggest that the sympathetic nervous system is more highly activated in insomnia patients.

• Sleep Medicine and Psychophysiology
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• v.23 no.2
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• pp.61-67
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• 2016

Objectives: We aimed to evaluate the effects of mattress type on both objective and subjective sleep quality in healthy good sleepers. Methods: Fifteen healthy good sleepers with a mean age of 30.8 years participated in this study. A randomized crossover trial was carried out using two different mattress types: a standard mattress and a contour coil mattress. After a night of adaptation, all participants were randomized to either a standard mattress or a contour coil mattress. Then, nocturnal polysomnography was conducted for two consecutive nights. Subjective evaluations were obtained using a self-report questionnaire before and after the polysomnographic recording sessions. Results: The polysomnographic showed no differences in total sleep time, sleep stage, or wake time after sleep onset between the two mattress conditions. Of the polysomnographic variables, only sleep onset latency was significantly reduced for the contour coil mattress. Additionally, participants reported better subjective sleep quality when sleeping on the contour coil mattress, according to the questionnaires. Conclusion: The type of mattress might affect not only subjective, but also objective sleep quality, including sleep onset latency.

• Science of Emotion and Sensibility
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• v.14 no.4
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• pp.645-652
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• 2011

This study examined changes of both psychological and physiological emotional responses according to change of the PMV (predicted mean vote) in the heating and the cooling air conditions. For this purpose, the changes of PMV were induced by the heating and cooling operations of the HVAC (heating, ventilation, and air conditioning) systems. In addition, positive/negative and arousal/relaxation were measured as the participant's psychological emotional responses, and HR (heart rate) was measured as the participant's physiological emotional responses. As a result, in same range of the PMV, both psychological and physiological emotional-responses were changed by air conditioning. It is suggested that occupant's emotional responses would depend on the operational conditions of heating and cooling in indoor thermal environments, and both psychological and physiological emotional response should be considered when occupants try to match the indoor thermal environments to their thermal expectations.

• Journal of Digital Convergence
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• v.12 no.10
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• pp.577-585
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• 2014

The cosmetic and stimulating effects of lemon oil have been widely proven in the fields of beauty therapy and psychology therapy. But the lemon oil's proper effects on the anti asthma and the anti inflammation have not rarely been verified. This study was conducted to find out the lemon oil's effects on the anti asthma and anti inflammation in the OVA-induced allergic asthma mice model. OVA-induced allergic asthma mice were divided into 4 groups consisting of normal group, control group, positive control group and experimental group. 0.3% of lemon oil was nebulized to experimental group for 3 weeks on a basis of 3 times per week and 30 min each time. After 6 weeks from the initial experiment, the degree of hyper activeness of respiratory system, the hematological change, the amount of the cytokein in serum, the change of airway organization were evaluated. The results showed that lemon oil controled effectively the hyper activeness of respiratory system and restricted the multiplication of cells in acidophil in terms of statistical significance. It also turned out that lemon oil restricted effectively the infection of airway reaction and the hyper sensitiveness of respiratory system by controlling the creation of histamine(cytokein) and IgE.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.407-421
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• 2016

This paper reports a meta-analysis of sixteen studies that evaluated the efficacy of cognitive behavioral therapy (CBT) for persistent primary insomnia. PubMed, Cochrane Library, EMBASE, CINAHL and several Korean databases were searched between January 2015 and June 2015. The main search strategy involved the terms that indicate CBT-I (Cognitive Behavioral Therapy-Insomnia) and presence of insomnia. Methodological quality was assessed using Cochrane's Risk of Bias. Data were analyzed by the RevMan 5.3 program of Cochrane Library. Sixteen clinical trials met the inclusion criteria, resulting in a total of 1503 participants. Stimulus control, sleep restriction, sleep hygiene education, and cognitive restructuring were the main treatment components. CBT-I was conducted for a mean of 5.4 weeks, 5.5 sessions, and an average of 90 minutes per session. The effects of CBT-i on total sleep time (d=-0.31), sleep onset latency (d=-0.29), awakening time after sleep onset (d=-0.55), sleep efficiency (d=-0.70), insomnia severity (d=-0.77) and sleep belief (d=-0.64) were significant. Overall, we found a range from small to moderate effect size. CBT-I also was effective for anxiety (d=-0.30) and depression (d=-0.35). The findings demonstrate that CBT-I interventions will lead to the improvement of both sleep quality and quantity in patients with insomnia.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.2
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• pp.101-106
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• 1987

A pot experiment was conducted to find out the effectiveness of ammonium sulfate absorbed Zeolite on the yield of rice and the changes of some plant nutrients under the condition of two levels of water percolation. The results were as follows: 1. Unhulled rice yield was increased in the plot of the percolation of 10 mm/day than the percolation of 30 mm/day due to the increase of panicle number and ripening ratio. 2. $NH^+_4-N$, $K^+$ and $SiO_2$ concentration in soil leachates were lower in the percolation rate of 10 mm/day than in the early stage of rice growth were decreased by the application of Zeolite 1.0 T/10a. 3. Plant uptakes of K and N in the harvesting stage were more accelerated in the percolation of 10 mm/day comparing with the percolation of 30 mm/day, and the silica uptake of plant was the reverse against the case of former elements. 4. The optimum rates of Zeolite for maximum yield were about 1T/10a.

• Sleep Medicine and Psychophysiology
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• v.19 no.2
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• pp.68-76
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• 2012

Objectives: Sleep disorders cause changes of autonomic nervous system (ANS) which affect cardiovascular system. Primary insomnia (PI) makes acceleration of sympathetic nervous system (SNS) tone by sleep deficiency and arousal. Obstructive sleep apnea syndrome (OSAS) sets off SNS by frequent arousals and hypoxemias during sleep. We aimed to compare the changes of heart rate variability (HRV) indices induced by insomnia or sleep apnea to analyze for ANS how much to be affected by PI or OSAS. Methods: Total 315 subjects carried out nocturnal polysomnography (NPSG) were categorized into 4 groups - PI, mild, moderate and severe OSAS. Severity of OSAS was determined by apnea-hypopnea index (AHI). Then we selected 110 subjects considering age, sex and valance of each group's size [Group 1 : PI (mean age=$41.50{\pm}13.16$ yrs, AHI <5, n=20), Group 2 : mild OSAS (mean age=$43.67{\pm}12.11$ yrs, AHI 5-15, n=30), Group 3 : moderate OSAS (mean age $44.93{\pm}12.38$ yrs, AHI 16-30, n=30), Group 4 : severe OSAS (mean age=$45.87{\pm}12.44$ yrs, AHI >30, n=30)]. Comparison of HRV indices among the four groups was performed with ANCOVA (adjusted for age and body mass index) and Sidak post-hoc test. Results: We found statistically significant differences in HRV indices between severe OSAS group and the other groups (PI, mild OSAS and moderate OSAS). And there were no significant differences in HRV indices among PI, mild and moderate OSAS group. In HRV indices of PI and severe OSAS group showing the most prominent difference in the group comparisons, average RR interval were $991.1{\pm}27.1$ and $875.8{\pm}22.0$ ms (p=0.016), standard deviation of NN interval (SDNN) was $85.4{\pm}6.6$ and $112.8{\pm}5.4$ ms (p=0.022), SDNN index was $57.5{\pm}5.2$ and $87.6{\pm}4.2$ (p<0.001), total power was $11,893.5{\pm}1,359.9$ and $18,097.0{\pm}1,107.2ms^2$(p=0.008), very low frequency (VLF) was $7,534.8{\pm}1,120.1$ and $11,883.8{\pm}912.0ms^2$ (p=0.035), low frequency (LF) was $2,724.2{\pm}327.8$ and $4,351.6{\pm}266.9ms^2$(p=0.003). Conclusions: VLF and LF which were correlated with SNS tone showed more increased differences between severe OSAS group and PI group than other group comparisons. We could suggest that severe OSAS group was more influential to increased SNS activity than PI group.

• Clinical and Experimental Pediatrics
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• v.50 no.11
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• pp.1097-1103
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• 2007

Purpose : Acute symptomatic seizure is defined as a temporary seizure together with acute systemic, metabolic, or toxic insult in association with an acute central nervous system insult. And unprovoked seizure is defined as seizure without provocating factors. We studied the risk factors of unprovoked seizures after acute symptomatic seizure in children. Methods : We retrospectively reviewed the records of one hundred and ten children with acute symptomatic seizures who were admitted to the pediatric department of Chungbuk National University Hospital between January, 1998 and December, 2003. We analyzed overall risk factors of unprovoked seizures after acute symptomatic seizures involving etiology, incidence, type of seizure, duration and neuroimaging. Results : We analyzed records of 110 children with acute symptomatic seizures aged from 1 month to 17 years. 24 children had unprovoked seizures (21.8%) after acute symptomatic seizures. Causes in order of frequency were encephalopathy, central nervous system infection, brain tumor, cerebrovascular disease. The risk of unprovoked seizure was significantly greater for those with status epilepticus (68.4%) than without status epilepticus, with partial seizure (64.7%) than generalized seizure. And the risk of unprovoked seizure was strongly associated with abnormal finding of electroencephalogram (79.1%) and neuroimaging (41.6%). Conclusion : In conclusion, the leading cause of subsequent unprovoked seizure in children with acute symptomatic seizure was encephalopathy and age specific incidence was high in the group aged 24-72 months. The risk for subsequent unprovoked seizure was greater for those with partial seizure, status epilepticus, abnormal finding of neuroimaging and electroencephalography.