• Tuberculosis and Respiratory Diseases
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• v.49 no.6
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• pp.715-723
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• 2000

Background : Obstructive sleep apnea syndrome (OSAS) affects systemic blood pressure and cardiac function. The development of cardiovascular dysfunction including the changes of systemic blood pressure and cardiac rhythm, suggests that recurrent hypoxia and arousals from sleep may increase a sympathetic nervous system activity. Continuous positive airway pressure (CPAP) therapy has been found to be an effective treatment of OSAS. However, only a few studies have investigated the cardiovascular and sympathetic effects of CPAP therapy. We evaluated influences of nasal CPAP therapy on the cardiovascular system and the sympathetic activity in patients with OSAS. Methods : Thirteen patients with OSAS underwent CPAP therapy and were monitored using polysomnography, blood pressure, heart rate, presence of arrhythmia and the concentration of plasma catecholamines, before and with CPAP therapy. Results: The apnea-hypopnea index (AHI) was significant1y decreased (p<0.01) and the lowest arterial oxygen saturation level was elevated significantly after applying CPAP (p<0.01). Systolic blood pressure tended to decrease after CPAP but without statistical significance. Heart rates during sleep were not significantly different after CPAP. However, the frequency and number of types of arrhythmia decreased and sinus bradytachyarrhythmia disappeared after CPAP. Although there was no significant difference in the level of plasma epinephrine concentration, plasma norepinephrine concentration significantly decreased after CPAP (p<0.05). Conclusion : CPAP therapy decreased the apnea-hypopnea index, hypoxic episodes and plasma norepinephrine concentration. In addition, it decreased the incidence of arrhythmia and tended to decrease the systemic blood pressure. These results indicate that CPAP may play an important role in the prevention of cardiovascular complications in patients with OSAS.

• Sleep Medicine and Psychophysiology
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• v.27 no.2
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• pp.51-55
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• 2020

In this paper, we reviewed domestic and foreign cases and evaluation methods for validation of sleep products for development of the domestic sleep industry. Foreign companies and organizations are trying to verify products relatively systematically for demonstration purposes, but they are using different methods depending on the institution, and standardized validation guidelines have not been established. In Korea, there has been little evaluation including objective verification for sleep products. Sleep-wake evaluation for validation of sleep products requires expert evaluation of the product and of the product effectiveness by users, and subjective and objective sleep-wake evaluations and circadian rhythm evaluation methods can be used. For more accurate verification, experimental designs such as randomization method, control product utilization method, and cross-experiment design can be used.

• Sleep Medicine and Psychophysiology
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• v.26 no.1
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• pp.16-22
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• 2019

Objectives: The objective of this study was to investigate the correlation between insufficient sleep and visuospatial memory in adolescents using a computerized neurocognitive function test. Methods: A total of 103 high school students (26 males and 77 females; mean age $17.11{\pm}8.50years$) without a serious psychiatric problem was recruited. All subjects were requested to complete a self-report questionnaire about weekday total sleep time and weekend total sleep time. The epworth sleepiness scale (ESS) and the beck depression inventory (BDI) were administered to measure daytime sleepiness and symptoms of depression. Seven subsets of the Cambridge Neuropsychological test automated battery were examined to assess visuospatial memory. Results: After controlling for age, sex, ESS, and BDI, longer weekend total sleep time was correlated with poor performance on delayed matching to sample (r = -0.312, p = 0.002) and immediate recall on pattern recognition memory (r = -0.225, p = 0.025). Increased weekend catch-up sleep time was correlated with poor performance of delayed matching to sample (r = -0.236, p = 0.018), immediate recall on pattern recognition memory (r = -0.220, p = 0.029), and delayed recall on pattern recognition memory (r = -0.211, p = 0.036) after controlling for age, sex, ESS, and BDI. Conclusion: This study showed that increased weekend catch-up sleep time reflecting insufficient weekday sleep were associated with poor performance in delayed recall tasks of visual memory. This finding suggests that insufficient sleep during adolescence might produce a decline of visuospatial memory.

• Sleep Medicine and Psychophysiology
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• v.17 no.1
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• pp.41-49
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• 2010

Unlike the case of adult obstructive sleep apnea syndrome (OSAS), there was no consistent finding on the changes of sleep architecture in childhood OSAS. Further understanding of the sleep electroencephalogram (EEG) should be needed. Non-linear analysis of EEG is particularly useful in giving us a new perspective and in understanding the brain system. The objective of the current study is to compare the sleep architecture and the scaling exponent (${\alpha}$) from detrended fluctuation analysis (DFA) on sleep EEG between OSAS and normal children. Fifteen normal children (8 boys/7 girls, 6.0${\pm}4.3$2.2 years old) and twelve OSAS children (10 boys/2 girls, 6.4${\pm}4.3$3.4 years old) were studied with polysomnography (PSG). Sleep-related variables and OSAS severity indices were obtained. Scaling exponent of DFA were calculated from the EEG channels (C3/A2, C4/A1, O1/A2, and O2/A1), and compared between normal and OSAS children. No difference in sleep architecture was found between OSAS and normal controls except stage 1 sleep (%) and REM sleep latency (min). Stage 1 sleep (%) was significantly higher and REM latency was longer in OSAS group (9.3${\pm}4.3$4.3%, 181.5${\pm}4.3$59.9 min) than in controls (5.6${\pm}4.3$2.8%, 133.5${\pm}4.3$42.0 min). Scaling exponent (${\alpha}$) showed that sleep EEG of OSAS children also followed the 'longrange temporal correlation' characteristics. Value of ${\alpha}$ increased as sleep stages increased from stage 1 to stage 4. Value of ${\alpha}$ from C3/A2, C4/A1, O1/A2, O2/A1 were significantly lower in OSAS than in control (1.36${\pm}4.3$0.05 vs. 1.41${\pm}4.3$0.04, 1.37${\pm}4.3$0.04 vs. 1.41${\pm}4.3$0.04, 1.37${\pm}4.3$0.05 vs. 1.41${\pm}4.3$0.05, and 1.36${\pm}4.3$0.07 vs. 1.41${\pm}4.3$0.05, p<0.05). Higher stage 1 sleep (%) in OSAS children was consistent finding with OSAS adults. Lower $'{\alpha}'$ in OSAS children suggests decrease of self-organized criticality or the decreased piling-up energy of brain system during sleep in OSAS children.

• Sleep Medicine and Psychophysiology
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• v.24 no.1
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• pp.12-18
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• 2017

Adequate amount and quality of sleep are important for metabolic control in patients with type 2 diabetes. Too short or too long sleep time disrupts glycemic control in both prediabetes and type 2 diabetic patients. Circadian misalignment such as shift work is also associated with an increased risk of developing type 2 diabetes. Clinicians should pay attention to the sleep problems and circadian patterns of patients. However, the pathophysiologic mechanism of the association between sleep and diabetes is likely to be complex and bidirectional. The underlying mechanism remains poorly understood, and further research is warranted.

• Sleep Medicine and Psychophysiology
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• v.9 no.1
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• pp.9-13
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• 2002

Alzheimer's disease (AD) is one of the most common and devastating dementing disorders of old age. Most AD patients showed significant alternation of sleep structure as well as cognitive deficit. Typical findings of sleep architecture in AD patients include lower sleep efficiency, higher stage 1 percentage, and greater frequency of arousals. The slowing of EEG activity is also noted. Abnormalities in REM sleep are of particular interest in AD because the cholinergic system is related to both REM sleep and AD. Several parameters representing REM sleep structure such as REM latency, the amount of REM sleep, and REM density are change in patients with AD. Especially, measurements of EEG slowing during tonic REM sleep can be used as an EEG marker for early detection of possible AD. In addition, a structural defect in the suprachiasmatic nucleus is suggested to cause various chronobiological alternations in AD. Most of alternations related to sleep make sleep disturbances common and disruptive symptoms of AD. In this article, the author reviewed the alternation of sleep structure and circadian rhythm in AD patients.

• Sleep Medicine and Psychophysiology
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• v.1 no.2
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• pp.188-192
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• 1994

The author reports a 32 years old female patient with late luteal phase dysphoric disorder who received evening bright light treatment for 7 consecutive days during the late luteal phase of menstrual cycle. After the treatment, beneficial clinical effects were observed. This result suggests that bright light can be an alternative treatment for LLPDD. However, the placebo effects should be ruled out completely. Further controlled studies with more patients will be needed.

• Sleep Medicine and Psychophysiology
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• v.26 no.2
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• pp.67-74
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• 2019

Anger is a multi-dimensional concept ranging from feeling irritable to violent aggression. A growing body of literature suggests the relevance of sleep in regard to anger. The current study aims to review previous studies on the association between anger and diverse aspects of sleep including sleep disruption, chronotype, sleep disorders and sleep deprivation. An association between sleep and anger has been observed starting in the early stage of life, with sleep of infants or toddlers affecting emotional and behavioral aspects of anger. However, the association between anger and sleep is not clear in adolescents and might be due to the effects of psychosocial factors on both sleep and anger during adolescence. Subjective but not objective sleep disturbances of adults have been also associated with anger. Evening types showed more anger, which might be mediated by psychological characteristics or social jet lag of evening people. Increased anger has also been found in those with insomnia, sleep apnea, or experimental sleep-deprivation. Previous studies have reported that diverse sleep disturbances are related to anger. Future study assessing the various sleep or circadian indices and considering the multidimensional aspects of anger are needed.

• Sleep Medicine and Psychophysiology
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• v.1 no.2
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• pp.125-144
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• 1994

Recently excessive daytime sleepiness was found to have relations with various social, occupational, and health problems. This condition is common symptom of several sleep disorders, among which sleep apnea syndrome is most contributive. It is essential to assess daytime sleepiness exactly for the diagnosis of such sleep disorders. Multiple sleep latency test which is a valid and objective measurement technique of sleepiness is time and cost consuming, and so there is increasing need of scales measuring general level of daytime sleepiness which are quick and simple to perform for clinical and research purpose. And also, there have been a lot of sleep researches viewing sleep as a chronobiological process, especially in the study of circadian type of shift workers. In these studies they used various techniques of multiple demensions to assess sleepiness or circadian rhythm which concerns various psychological variables. Of these measurement techniques circadian type questionnaires might have some problems in their psychometric properties. So some of these morningness-eveningness questionnaires have been revised and more valid scales are being suggested by different authors. The author briefly reviewed various measurement techniques of sleepiness and circadian rhythm and introduced recently developed scales which are more valid allegedly, and finally discussed psychometric properties of these morningness-eveningness questionnaires.

• Sleep Medicine and Psychophysiology
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• v.4 no.1
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• pp.66-76
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• 1997

Objectives : The purpose of this study is to analyse sleep habits and sleep disorders in the elderly population ased 65-84 years. Methods : Epidemiological survey was performed at home by means of semi structured interviews in the city of Pusan, Korea. Subjects were randomly selected. The questionnaire consisted of 128 items including demographic findings, sleep habits, sleep disorders, somatic illnesses, and psychological distresses. Results : (1) The mean retiring time was 10.28 h (SD 1.30 h) and the mean wake-up time was 5.24 h (SD 1.33 h). The mean duration of sleep was 5.63 h (SD 1.80 h). The mean sleep onset time was 44.51 min. The mean frequency of daytime napping was 2.49 (SD 3.23). The subjects reported they woke up an average of 2.05 (SD 1.59) times per night. All of the above results were not related to age or gender. However, the mean frequency of difficulty in initiating/maintaining sleep was 2.2 times for men and 3.2 times for women (p<0.05). (2) The prevalence of insomnia was 57.7% and was not related to age or gender. Difficulty in initiating sleep was the most commonly reported insomnia complaint(52.4%). Early morning awakening was reported by 50.0% of patients and difficulty in maintaining sleep was reported by 45.1% of them. Worrying in bed and physical pain were strong contributing factor to insomnia. Conclusions : The results of our study showed several characteristics of sleep habits in the elderly. Sleep disorder in old age is not inevitable or trivial. Since sleep disturbance in older adults is common and distressing, it has implications for general health and well-being. Active concern and therapeutic intervention for the sleep habits and sleep disorders in the elderly are needed.