• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.20 no.3
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• pp.146-151
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• 2009

Objectives : We conducted this study to investigate the relationship between sleep duration and body mass index (BMI), in Korean children. Methods : We performed a cross-sectional analysis of data collected on 3,639 boys and girls (aged 7-12) in Daegu, Korea. The data included each child's age, sex, weight, height, extracurricular activities, bedtime, wake-up time, sleep latency, total sleep duration, parents' occupations, and parents' educational levels. The relationship between sleep duration and each variable was examined via analysis of variance (ANOVA). Results : The analysis showed an association between short sleep duration and high BMI. Boys showed a graded inverse relationship between sleep duration and BMI. However, there was no significant corresponding result for girls. In the total sample, hours of computer use, time when the computer was turned off, time when the television was turned off, mother's bedtime, and hours of extracurricular activity were associated with longer sleep duration. No association was found between sleep duration and hours of watching television, child's wake-up time, or educational level of the parents. Conclusion : The results of this study show an inverse relationship between a child's sleep duration and BMI；thus, children with shorter sleep duration tend to have higher BMIs.

• Korean Parent-Child Health Journal
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• v.3 no.1
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• pp.46-59
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• 2000

The purpose of this study is to determine whether the NCASA (Nursing Child Assessment Sleep/Activity Record) would be suitable to evaluate and to provide the basic resources for a Korean model of sleep/activity patterns during the first 6 months Korean infants' lives and to provide a basis for nursing intervention for mothers of early infants. The subjects of this study were 94 normal infants from birth to 6 months of age who visited the postpartum care center and two general hospitals located in Pusan from February 1 to April 28, 2000. The method of data collection was through convenient sampling. The instrument of this study was the NCASA translated by the Korean parent Child Health Academic Association. The collected data were analysed by mean, standard deviation, frequency percentage and ANOVA, Post Hoc test by use of SPSS/PC. The conclusions obtained from this study are summarized as follows: 1. The mean amount of daytime sleep was 8.06 hours. The mean amount of nighttime sleep was 6.31 hours. The mean amount of total daily sleep was 14.37 hours. The mean of the longest sleep period was 5.20 hours. The mean regularity of daytime sleep was 25.84%. The mean regularity of nighttime sleep was 77.69%. The mean regularity of total daily sleep was 42.60%. The mean frequency of nighttime wakenings was 2.33 times. 2. The mean amount of daytime activity was 8.25 hours. The mean amount of nighttime activity was 1.39 hours. The mean amount of daily total activity was 9.64 hours. The mean of the longest activity period was 3.80 hours The mean frequency of daytime feeding was 5.69 times. The mean frequency of nighttime feeding was 2.08 times. The mean frequency of total daily feeding was 7.74 times. The mean frequency regularity of feeding was 54.62%. The mean frequency of wakenings was 5.14 times. The mean frequency of crying was 1.90 times. 3. According to an analysis of sleep patterns based on an infant's age, there were some significant differences in the following factors: amount of daytime sleep(p<.001), amount of night time sleep(p<.05), amount of total daily sleep (p<.001), longest sleep period(p<.001), regularity of daytime sleep(p<.001), regularity of nighttime sleep(p<.01), regularity of total daily sleep(p<.001), frequency of nighttime wakenings(p<.001). 4. According to an analysis of activity patterns based on an infant's age, there were some significant differences in the following factors: amount of daytime activity(p<.001), amount of nighttime activity(p<.01), amount of total daily activity(p<.001), longest activity period(p<.05), frequency of nighttime feeding(p<.01), frequency of wakenings(p<.001). 5. The mean amount of a mother's day time was 16.30 hours. The mean amount of a mother's night time was 7.70 hours. In conclusion, the initial irregular sleeping and activity patterns of the early infant became regurized as the infant grew older and estabilished firmer patterns of sleeping and of activity.

• Journal of the Korean Operations Research and Management Science Society
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• v.32 no.4
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• pp.89-99
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• 2007

In this paper, an analytic model of a sleep mode operation in the IEEE 802.16e is investigated. A mobile subscriber 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/l 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.11 no.1
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• pp.10-16
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• 2004

Sleep is associated with definite changes in respiratory function in normal human beings. During sleep, there is loss of voluntary control of breathing and a decrease in the usual ventilatory response to both low oxygen and high carbon dioxide levels. Especially, rapid eye movement (REM) sleep is a distinct neurophysiological state associated with significant changes in breathing pattern and ventilatory control as compared with both wakefulness and non-rapid eye movement (NREM) sleep. REM sleep is characterized by erratic, shallow breathing with irregularities both in amplitude and frequency owing to marked reduction in intercostal and upper airway muscle activity. These blunted ventilatory responses during sleep are clinically important. They permit marked hypoxemia that occurs during REM sleep in patients with lung or chest wall disease. In addition, sleep-disordered breathing (SDB) is more frequent and longer and hypoventilation is more pronounced during REM sleep. Although apneic episodes are most frequent and severe during REM sleep, most adults spend less than 20 to 25% of total sleep time in REM sleep. It is, therefore, possible for patients to have frequent apneas and hypopneas during REM sleep and still have a normal apnea-hypopnea index if the event-rich REM periods are diluted by event-poor periods of NREM sleep. In this review, we address respiratory physiology according to sleep stage, and the clinical implications of SDB and hypoventilation aggravated during REM sleep.

• Korean Journal of Clinical Laboratory Science
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• v.39 no.3
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• pp.264-270
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• 2007

Obstructive sleep apnea syndrome (OSAS) is defined by sleep apnea with decreased oxygen saturation, excessive snoring with daytime sleepiness, and frequent awakening during the night time sleep. The present study was performed to investigate how apnea-hypopnea, that possibly causes breathing disturbance during sleep, can affect sleep pattern in patients with OSAS. We included 115 patients (92 men, 23 women) who underwent a polysomnography from January 2006 to May 2007. As the frequency of sleep apnea-hypopnea increases, the proportion of non-rapid eye movement (REM) sleep (p<0.001), and stage I sleep (p<0.001) increased, while that of stage II sleep (p<0.001), stage III and IV sleep (p<0.01), and REM sleep (p<0.05) decreased. Furthermore, sleep apnea-hypopnea was closely correlated with REM sleep (r=0.314, p<0.001), stage I sleep (r=0.719, p<0.001), stage II sleep (p=-0.342, p<0.05), stage III and IV sleep (r=-0.414, p<0.001), and REM sleep (r=-0.342, p<0.05). Stage I sleep could account for the 51% of the variance of apnea-hyponea. Our study shows sleep apnea-hypopnea affects sleep pattern in pattern with OSAS significantly, and the change of stage I sleep is the most important factor in estimating the disturbance of sleep pattern.

• Sleep Medicine and Psychophysiology
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• v.23 no.2
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• pp.68-76
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• 2016

Objectives: To find evidence that sleep is necessary for normal brain function, thus indicating that declines in both sleep quality and quantity are related to worse performance of many daily tasks and deteriorated physical functions. The present study investigates the relationships of balance control and reaction time with sleep quality. Methods: 58 healthy (male 20, female 38) volunteers with informed consent participated in this study. The Self-reported Pittsburgh Sleep Quality Index (PSQI) was used to evaluate sleep quality and relevant factors, and the subjects were divided into groups A (PSQI < 5) and B ($PSQI{\geq}5$) based on this index. Static balance control and reaction time to visual stimuli were conducted to assess their relationship with sleep quality. Results: Group B exhibited excessive daytime sleepiness significantly more often compared to group A. Static balance control did not markedly change relative to sleep quality, but reaction time and error to visual stimuli were significantly increased in group B compared to group A. Conclusion: These findings indicate that a decline in sleep quality can result in delayed reactions, as well as decreased accuracy of these reactions. They also suggest that low sleep quality may be associated with changes in physical functions, including balance control through reduced selective attention.

• Korean Parent-Child Health Journal
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• v.3 no.2
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• pp.1-17
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• 2000

The purpose of this study was to recognized the sleep activity patterns of the normal infants in Korea. The subject were 41 normal infants who were below 8 weeks old and were born in Taegu city and Kyungbuk province. The measuring instrument the sleep activity was NCASA translated by the Korean-parent-child Health Academic Association. The data that were collected from April, 18 1999 to January 1, 2000 were analysed by the SPSS 7.5 program. The results of the study was summarized as follow; 1) The mean amount of total sleeping hours per day was decreased from $16.27{\pm}1.96$ hr at the 1st week, to $15.19{\pm}2.39$ hr at the 2nd week, to $13.66{\pm}2.40$ hr at the 3 week but increased to $16.55{\pm}5.77$ hr at the 4-8 week after birth. 2) The mean frequency of feeding was increased to $9.43{\pm}2.79$ times at the 3rd week but decreased to $7.55{\pm}1.23$ times at the 4-8th week after birth. 3) The regularity of day time sleep was decreased from 50.00% to 19.79% and that of night time sleep was increased from 51.79% to 72.92%. 4) The regularity of feeding was increased from 30.42% at the 1st week to 50.07% at the 2nd week but decreased 26.34% at the 4-8th week after birth. 5) The longest period of day time sleep was decreased to $2.39{\pm}0.42$ hr at the 3rd week but increased $2.47{\pm}0.69$ hr at the 4-8th week after birth. The longest period of night time sleep was decreased to $2.58{\pm}0.67$ hr at the 2nd week but increased to $3.00{\pm}1.32$ at the 3rd week and $4.30{\pm}1.16$ hr at the 4-8th week after birth. 6) At the 1st week, the 2nd week, the 3rd week after birth, the frequency of day time feeding was positively correlated with the frequency of night time feeding($R_{1week}=0.948^{**}$, $R_{2week}=0.927^{**}$, $R_{3week}=0.779^{**})$. At the 4-8th week after birth, the frequency of night time feeding was negatively correlated with the amount of night time sleep ($R_{4week-8week}=0.875^{*}$). On the basis of above findings, the following is suggested; It is need a longitudinal and transcultural study which are designed for children's sleep and feeding.

• Research in Community and Public Health Nursing
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• v.30 no.1
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• pp.79-89
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• 2019

Purpose: The purpose of this paper is to determine effects of auricular acupressure on knee pain, range of motion, and sleep in the elderly with knee osteoarthritis. Methods: This is an experimental study designed with randomization and single-blind in a placebo-control approach. The subjects included the elderly with knee osteoarthritis who were using an elderly welfare facility. In each of the groups, 28 subjects were assigned. For the experimental group, auricular acupressure was applied to five pressure points related to the pain caused by osteoarthritis and sleep. In the case of the placebo-control group, auricular acupressure was applied to other five points than the former. The intervention lasted eight weeks. In order to examine intervention effects of auricular acupressure, joint pain, Pressure Pain Thresholds (PPTs), and extension and flexion range of motion (ROM) were measured weekly. As for the preand post-examinations, pain, sleep quality, and the time-by-sleep stage of the patients with knee osteoarthritis were measured. Results: The VAS scores in the experimental group with auricular acupressure significantly decreased through time (p<.001) and WOMAC also significantly decreased (p<.01) compared with the placebo-control group. However, there were no significant differences in PPTs. The flexion (p<.01) and extension (p<.001) ROMs measured for eight weeks improved over time. Meanwhile, sleep quality improved significantly after the intervention termination (p<.01), but there was no significant difference found in the time-by-sleep stage. Conclusion: Auricular acupressure applied for eight weeks was found to be effective in reducing joint pain, improving knee ROM, and improving sleep quality in patients with degenerative knee arthritis.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.5
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• pp.240-247
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• 2006

Frequent arousals during sleep degrade the quality of sleep and result in sleep fragmentation. Visual inspection of physiological signals to detect the arousal events is cumbersome and time-consuming work. The purpose of this study is to develop an automatic algorithm to detect the arousal events. The proposed method is based on time-frequency analysis and the support vector machine classifier using single channel electroencephalogram (EEG). To extract features, first we computed 6 indices to find out the informations of a subject's sleep states. Next powers of each of 4 frequency bands were computed using spectrogram of arousal region. And finally we computed variations of power of EEG frequency to detect arousals. The performance has been assessed using polysomnographic (PSG) recordings of twenty patients with sleep apnea, snoring and excessive daytime sleepiness (EDS). We could obtain sensitivity of 79.65%, specificity of 89.52% for the data sets. We have shown that proposed method was effective for detecting the arousal events.

• Journal of Families and Better Life
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• v.32 no.2
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• pp.41-52
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• 2014

The present study investigated the sleep patterns 1-to 3-year-old children and examined whether their sleep patterns would predict their early adjustment to daycare centers. The participants were 239 young children attending daycare centers in Seoul. The data on children's sleep patterns were collected by parent report. Children's adjustment to daycare was assessed by daycare providers' reports. The data were analyzed by means of Chi-square test, t-test, Pearson's correlation, ANOVA and discriminant analysis. The results were as follows: Children from dual-earner families had shorter nocturnal sleep duration than those from single-earner families. There was no significant relation between daytime sleep duration and sleep-onset time at night. It was found that children who go to bed earlier were more likely to get sufficient sleep without nocturnal wakefulness. Age and total sleep duration were seen to be significant variables when it came to discriminating between the adjustment versus maladjustment groups.