• The Journal of the Korea institute of electronic communication sciences
• /
• v.11 no.2
• /
• pp.223-228
• /
• 2016

People try to maintain optimal sleep activity to a changing attitude 20-30 times while sleeping 7-8 hours a day. In order to provide optimal sleep, we need to develop sensing device for apply effective various sleep data acquired through display device that can provide program and information which process and analyze information printed out from sensor and sensing system. In this paper, we analyze sleep pattern to detect the toss and turn while a person's sleeping and we develop a wellness pillow that can be active on sleep health management based on the analyzed data for sleep patterns.

• Sleep Medicine and Psychophysiology
• /
• v.16 no.1
• /
• pp.22-27
• /
• 2009

Regulation of respiration differs significantly between wakefulness and sleep. Respiration during wakefulness is influenced by not only automatic control but also voluntary and behavioral control. Sleep is associated with definite changes in respiratory function. With the onset of sleep, voluntary control of ventilation that overrides automatic control during wakefulness becomes terminated. Also ventilatory response to various stimuli including hypoxemia and hypercapnia is decreased. With these reasons respiration during sleep becomes fragile and unstable so that marked hypoxemia can be happened in patients with lung disease especially during REM sleep. Obstructive sleep apnea may also be developed if upper airway resistance is increased in addition to these blunted ventilatory responses.

• Sleep Medicine and Psychophysiology
• /
• v.6 no.2
• /
• pp.102-109
• /
• 1999

Headaches and sleep problems are common complaints in clinical practice. The relationship of sleep and headache has been extensively studied. Brain systems involved in the regualtion of sleep may also play a role in the initiation of vascular headache. Some of the physiological alterations in sleep, particularly REM sleep, are similar to those described in vascular headache. Clinical studies have documented an association between vascular headache and sleep, and headache is a common symptom of sleep disorders. Sleep and headache are known to be interrelated in several ways. It can be summarized as follows: 1) sleep-related headaches, 2) sleep phase-related headaches, 3) length of sleep(excess, lack, and disruption) and headaches, 4) headache related to sleep associated behavior, 5) sleep disorders and headaches, 6) effects of headaches on sleep, and 7) dreams and headaches. Several mechanisms can be proposed to explain the relationship between sleep and headaches.

• Sleep Medicine and Psychophysiology
• /
• v.27 no.2
• /
• pp.33-40
• /
• 2020

An infant's sleep varies considerably from that of adults in terms of structure, amount, and breathing pattern. After birth, sleep becomes evenly distributed throughout the day and night. Nighttime sleep gradually increases with the maturation of circadian rhythm, and sleep is gradually consolidated. Electroencephalography characteristics change with age, from early and dominant active (REM) sleep in newborns to increasing NREM sleep. Similar to other elements of growth, the upper respiratory tract and ribcage gradually increase in size with age, and respiratory control also improves. With these changes, sleep patterns also change. At this time that various sleep disorders may appear. Improved understanding of age-dependent changes in infant sleep can help determine the etiology and facilitate diagnosis of infant sleep diseases.

• Sleep Medicine and Psychophysiology
• /
• v.29 no.1
• /
• pp.1-3
• /
• 2022

Sleep is associated with Alzheimer's dementia. Many previous researches have shown that inadequate sleep is one of the risk factors that predict Alzheimer's dementia. The causal mechanism of this association is not clear. Slow wave sleep and REM sleep are critical stages in memory consolidation, and by sequential hypothesis both stages are important. Deposition of amyloid beta and tau, the main pathology of Alzheimer's dementia, are also associated with sleep. This review provides the association of sleep and Alzheimer's dementia, and future research is necessary to examine the specific mechanism of this association between sleep and Alzheimer's dementia, which may lead to an early intervention in sleep.

• Sleep Medicine and Psychophysiology
• /
• v.13 no.2
• /
• pp.45-51
• /
• 2006

Obstructive sleep apnea (OSA) syndrome disrupts normal sleep. However, there were few studies to evaluate the asymmetric distribution, the one of the important factors of normal sleep in OSA subjects. We hypothesized that asymmetry would be broken in OSA patients. 49 male subjects with the complaint of heavy snoring were studied with polysomnography. We divided them into two groups based on the apnea-hypopnea index (AHI) fifteen: 13 simple snoring group (SSN, average AHI $5.9{\pm}4.4$) and 32 OSA group (average AHI $47.3{\pm}23.9$). We compared split sleep variables between the first half and the second half of sleep within each group with paired t-test for the evaluation of asymmetry. Changes of sleep architecture of OSA were higher stage 1 sleep% (S1), total arousal index (TAI), AHI, and mean heart rate (HR) and lower stage 2 sleep% (S2), REM sleep%, and mean arterial O2 saturation (SaO2) than SSN subjects. SWS and wake time after sleep onset (WASO) were not different between two groups. In split-night analysis, OSA subjects showed higher S2, slow wave sleep% (SWS), spontaneous arousal index (SAI), and mean HR in the first half, and higher REM sleep% and mean SaO2 in the second half. Those were same pattern as in SSN subjects. Mean apnea duration and longest apnea duration were higher in the second half only in the OSA. No differences of AHI, ODI, WASO, and S1 were found between the first and the second half of sleep in both groups. TAI was higher in the first half only in the SSN. SWS and WASO seemed to be influenced sensitively by simple snoring as well as OSA. Unlike our hypothesis, asymmetric distributions of major sleep architecture variables were preserved in OSA group. Losing asymmetry of TAI might be related to pathophysiology of OSA. We need more studies that include large number of subjects in the future.

• Sleep Medicine and Psychophysiology
• /
• v.8 no.2
• /
• pp.113-120
• /
• 2001

Objectives: Obstructive sleep apnea syndrome is common and may produce various symptoms and serious complications. A substantial number of research articles on obstructive sleep apnea syndrome have been published in Korea. However, we found such limitations as lack of sufficient sample size and lack of polysomnography-proven cases. Therefore, we aimed at studying clinical features and sleep structure in a sufficient number of Korean patients with obstructive sleep apnea syndrome diagnostically confirmed with polysomnography. Methods: We studied 801 subjects referred to the Division of Sleep Studies, Seoul National University Hospital, who were diagnosed as having obstructive sleep apnea syndrome with polysomnography. Subjects were excluded if they had central sleep apnea syndrome, periodic limb movement disorder, narcolepsy or REM sleep behavior disorder. Foreign patients were also excluded. First of all, we studied the clinical features of the subjects. Secondly, we compared sleep-related parameters of the study subjects with those of age/sex-matched normal values. Thirdly, correlations of respiratory disturbance index (RDI) with each of the sleep-related parameters were calculated. Results: Among the 801 subjects, 668 were male subjects (83.4%) and 133 female subjects (16.4%). Their mean age was 46.6 years (${\pm}13.5$). The mean body mass index (BMI) was 25.8 (${\pm}3.8$) and subjects with BMI was over 28.0 accounted for 22.8% of the total. Fifty subjects (6.2%) were found to take benzodiazepines. Mean RDI and mean nocturnal oxygen saturation of all subjects was 31.2 (${\pm}24.4$) and 94.5% (${\pm}3.6$), respectively. In comparison with normal values, the subjects showed longer sleep latency, lower sleep efficiency, decreased total slow wave sleep % (TSWS %), and decreased total REM sleep % (TREM %)(p<0.01 in all). RDI had a negative correlation with each TSWS % and TREM % (p<0.01, p<0.01). However, RDI did not have significant correlation with either sleep latency or sleep efficiency. Conclusion: In this study, 6.2% of patients diagnosed as having obstructive sleep apnea syndrome were found to take benzodiazepines, although they are generally considered to be of litte benefit or even dangerous because of the respiratory suppressing effect. The proportion of obese subjects was only 22.8% and Korean patients with obstructive sleep apnea syndrome seem to be less obese than those described in foreign journals. This study also suggests that the severity of obstructive sleep apnea syndrome may have a more significant effect on sleep architecture defined as TSWS % and TREM % than on sleep efficiency.

• Sleep Medicine and Psychophysiology
• /
• v.24 no.1
• /
• pp.5-11
• /
• 2017

The use of alcohol is associated with the development and worsening of sleep disorder. Alcohol is generally known to have a sedative effect, but it has an arousal or sedative effect depending on the timing and drinking dose and directly affects REM sleep physiology. Alcohol acts on the central nervous system (CNS) to interfere with the sleep-wake cycle and to affect sleep-related hormone secretion. In addition, the ingestion of alcohol pre-sleep is associated with deterioration and development of sleep related breathing disorders (SBD). The increase in resistance of the upper respiratory tract and the decrease in sensitivity of the CNS respiratory center and the respiratory muscles are major mechanisms of alcohol-induced SBD, and result in snoring or apnea in healthy men or aggravating apnea in patients with OSA. Sleep-related restless leg syndrome and circadian rhythm disorders are common in alcohol use disorder patients. This review provides an assessment of scientific studies that investigated on the impact of alcohol ingestion on nocturnal sleep physiology and sleep disorders.

• Sleep Medicine and Psychophysiology
• /
• v.7 no.1
• /
• pp.43-50
• /
• 2000

Objectives: Obstructive sleep apnea syndrome(OSAS) is known to be associated with the changes of autonomic nervous system (ANS). Nasal continuous positive airway pressure(nCPAP) treatment was found to correct abnormal ANS changes in OSAS but it remains to be further clarified. We aimed to assess the effects of nCPAP on ANS manifested on electrocardiogram, using spectrum analysis in the subjects with OSAS. Methods: Digital polysomnography was performed in 18 patients with OSAS(mean age $43.7{\pm}16.6$ years ; 17 males, 1 female ; mean respiratory disturbance index (RDI) $48.6{\pm}20.9$) for one baseline and another CPAP nights. From each night, 300 continuous beats of ECGs without artifact were chosen from both stage 2 sleep and REM sleep and they were used for power spectrum analysis. We compared between baseline and CPAP nights the heart rate variability including VLF(very low frequency power), LF (low frequency power), HF(high frequency power), R-R means, R-R variance, and LF/HF ratio, using Wilcoxon signed ranks test. Results: In all patients, nCPAP proved to be effective in relieving apneas and snoring. During nCPAP night compared with baseline night, decreases in VLF(p<0.05), LF(p<0.01), and R-R variance(p<0.05) were found in stage 2 sleep, and decreased LF(p<0.05) was found in REM sleep. No significant differences in each sleep stage were found in other variables between the two nights. Conclusion: Our findings suggest that OSAS increases the activity of sympathetic nervous system and nCPAP application effectively decreases the activity. And nCPAP does not appear to influence the parasympathetic nervous activity in OSAS.

• Sleep Medicine and Psychophysiology
• /
• v.30 no.1
• /
• pp.9-12
• /
• 2023

Periodic limb movements during sleep (PLMS) are prevalent in various sleep disorders, such as restless legs syndrome (RLS), periodic limb movements disorder, obstructive sleep apnea (OSA), REM sleep behavior disorder (RBD), and narcolepsy. PLMS has been hypothesized to be related to the decline of dopaminergic transmission. In RLS, PLMS is suggested to be related to iron deficiency and symptom severity. PLMD is a rare sleep disorder, and the role of PLMS in PLMD has not been clearly investigated yet. PLMS in OSA, which remain after proper PAP therapy, may need further management. The clinical relevance of PLMS in RBD and narcolepsy have not been investigated thoroughly and need further studies. Whether PLMS are to be considered as a mere symptom of individual sleep disorders or not can be elucidated through studies investigating the efficacy of therapeutic approaches to reduce PLMS in various sleep disorders.