• Tuberculosis and Respiratory Diseases
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• v.45 no.2
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• pp.404-415
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• 1998

Background: Sleep apnea syndrome, which occurs in 1~4 % of the adult population, frequently has different cardiovascular complications such as hypertension, ischemic heart disease, cardiac arrythmia as well as sleep-wake disorder such as excessive daytime hypersomnolence or insomnia. Mortality and vascular morbidity are reported to be significantly higher in sleep apnea syndrome patients than in normal population. According to the recent studies, autonomic dysfunction as well as hypoxemia, hypercapneic acidosis, and increased respiratory effort, may playa role in the high prevalence of cardiovascular complications in patients with sleep apnea syndrome. However the cause and mechanism of autonomic neuropathy in patients with sleep apnea syndrome are not well understood. We studied the existence of autonomic neuropathy in patients with sleep apnea syndrome and factors which influence the pathogenesis of autonomic neuropathy. Method: We used the cardiovascular autonomic neuropathy(CAN) test as a method for evaluation of autonomic neuropathy. The subjects of this study were 20 patients who diagnosed sleep apnea syndrome by polysomnography and 15 persons who were normal by polysomnography. Results: Body mass index and resting systolic blood pressure were higher in sleep apnea group than control group. Apnea index(Al), respiratory disturbance index(RDI) and snoring time percentage were significantly higher in sleep apnea group compared with control group. But there were no significant differences in saturation of oxygen and sleep efficiency in two groups. In the cardiac autonomic neuropathy test, the valsalva ratio was significantly low in sleep apnea group compared with control group but other tests had no differences between two groups. The CAN scores and corrected QT(QTc) interval were calculated significantly higher in sleep apnea group, but there were no significant correlations between CAN scores and QTc interval. There were no significant data of polysomnography to correlate to the CAN score. It meant that the autonomic neuropathy in patients with sleep apnea was affected by other multiple factors. Conclusion: The cardiovascular autonomic neuropathy test was a useful method for the evaluation of autonomic neuropathy in patients with sleep apnea syndrome and abnormalities of cardiovascular autonomic neuropathy were observed in patients with sleep apnea syndrome. However, we failed to define the factors that influence the pathogenesis of autonomic neuropathy of sleep apnea syndrome. This study warrants futher investigations in order to define the pathogenesis of autonomic neuropathy in patients with sleep apnea syndrome.

• Journal of Preventive Medicine and Public Health
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• v.46 no.6
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• pp.329-335
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• 2013

Objectives: To comprehensively examine the relationship between current sleep duration and past suicidal idea or attempt among Korean adolescents. Methods: Data came from the 2009 Korea Youth Risk Behavior Web-based Survey with 75 066 participants (with the participation rate of 97.6%) in 800 middle and high schools. Binary logistic regression was conducted by gender and depressed mood to identify significant factors for suicidal ideation/attempt. The dependent variable was the log odds of suicidal ideation/attempt, while the independent/control variables were sleep duration and other demographic, socio-economic and health-related factors. Results: A negative association between sleep duration and suicidal ideation or attempt was weaker for those with depressed mood than for those without such experience in Korea for Year 2009. The odds ratio of suicidal ideation/attempt regarding less than 4 hours of sleep compared to 6 to 7 hours of sleep, was smaller in a group with depressed mood than in a group without such experience, for example, 1.64 (95% confidence interval [CI], 1.29 to 2.08) vs. 2.06 (95% CI, 1.34 to 3.17) for men's suicidal ideation, 2.50 (95% CI, 1.69 to 3.69) vs. 3.89 (95% CI, 1.74 to 8.66) for men's suicidal attempt. A negative association between age (or self-rated health) and suicidal ideation/attempt was also weaker for those with depressed mood than for those without such experience in the nation for the year. Conclusions: There was a negative association between sleep duration and suicidal ideation/attempt in Korea for Year 2009 and this association was weaker for those with depressed mood than for those without such experience. Based on the findings of this study, adolescents' better mental health and longer, more comfortable sleep might help to prevent their suicidal ideation and attempt in Korea.

• Korean Journal of Biological Psychiatry
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• v.21 no.2
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• pp.74-80
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• 2014

Objectives More than half of the elders suffer from chronic sleep disturbances. Moreover, sleep disturbances are more prevalent in patients with depressive disorder than in community dwelling elderly. In this study, we aim to estimate the risk factors of poor sleep quality and its effect on quality of life in patients with late life depression. Methods This study included 159 depressive patients aged 65 years or older who completed Pittsburgh Sleep Quality Index (PSQI). A global PSQI score of 5 or greater indicates a poor sleeper. Structural diagnostic interviews were performed using the Korean version of Mini International Neuropsychiatric Interview (MINI). Depression was evaluated by the Korean form of Geriatric Depression Scale (KGDS). Global cognition was assessed by Mini-Mental State Examination in the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease assessment packet. Quality of life was evaluated by the Korean version of Short-Form 36-Item Health Survey (SF-36). Results The frequencies of poor sleepers were 90.5% in major depressive disorder, 71.8% in minor depressive disorder, 47.1% in subsyndromal depressive disorder, and 73.0% in all types of depressive disorders. Multivariate logistic regression analysis indicated that female [odds ratio (OR) = 2.83, 95% confidence interval (CI) = 1.20-6.67] and higher KGDS score (OR = 1.13, 95% CI = 1.05-1.21) were risk factors of poor sleep quality in patients with late life depression. In the analysis of ANCOVA adjusted for age, gender, education and KGDS score, the mean scores of vitality mental health and mental component summary of SF-36 were lower in poor sleepers than in good sleepers. Conclusions Poor sleepers among patients with late life depression are very common and are associated with female and higher KGDS scores. Poor sleep quality causes a significant negative effect on mental health quality. So researchers and clinicians should be more vigilant in the evaluation and treatment of sleep disturbances in patients with late life depression.

• Annals of Occupational and Environmental Medicine
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• v.35
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• pp.47.1-47.14
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• 2023

Background: This study aimed to examine the impact of chronotype on depressive symptoms and explore the mediating effects of sleep quality, pre-sleep cognitive arousal, and social jetlag in a sample of wage earners. Methods: A total of 3,917 waged workers were surveyed online in July 2022. Logistic regression and mediation analysis were used to assess the relationship between chronotype (morningness, intermediate, and eveningness) and depressive symptoms (Patient Health Questionnaire ≥ 5), and the mediating effects of Insomnia Severity Index (ISI), Pittsburgh Sleep Quality Index (PSQI), and Pre-Sleep Arousal Scale (PSAS). All analyses were adjusted for age, education level, income level, marital status, coffee consumption, alcohol consumption, physical activity, occupation, employment status, and working hours to calculate odds ratios (ORs). Results: The chronotypes of all the participants were divided into morningness (4.7%), intermediate (93.5%), and eveningness (1.8%). Multiple logistic regression analysis showed an increased risk of depression in the eveningness chronotype (OR: 2.96; 95% confidence interval [CI]: 1.51, 5.86). Regarding the mediation analysis, ISI mediated 28.44% (95% CI: 16.39-40.5), PSQI for 31.25% (95% CI: 19.36, 43.15), and PSAS-Cognitive Score (PSAS-C) for 23.58% (95% CI: 10.66, 36.50) of the association between chronotype and depressive symptoms. However, social jetlag did not significantly mediate this relationship. (percentage mediated = 0.75%, 95% CI: -3.88, 5.39) Conclusions: Evening chronotypes exhibit an increased risk of depressive symptoms, which ISI, PSQI, and PSAS-C partially mediated. This suggests that interventions to improve sleep quality and maintain adequate sleep habits may effectively prevent and treat depression in employees with an eveningness chronotype.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.3 s.303
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• pp.47-52
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• 2005

Obstructive Sleep Apnea (OSA) is a representative symptom of sleep disorder caused by the obstruction of upper airway. Because OSA causes not only excessive daytime sleepiness and fatigue, hypertension and arrhythmia but also cardiac arrest and sudden death during sleep in the severe case, it is very important to detect the occurrence and the frequency of OSA. OSA is usually diagnosed through the laboratory-based Polysomnography (PSG) which is uncomfortable and expensive. Therefore researches to improve the disadvantages of PSG are needed and studies for the detection of OSA using only one or two parameters are being made as alternatives to PSG. In this paper, we developed an algorithm for the detection of OSA based on Heart Rate Variability (HRV). The proposed method is applied to the ECG data sets provided from PhysioNet which consist of learning set and training set. We extracted features for the detection of OSA such as average and standard deviation of 1 minute R-R interval, power spectrum of R-R interval and S-peak amplitude from data sets. These features are applied to the input of neural network. As a result, we obtained sensitivity of $89.66\%$ and specificity of $95.25\%$. It shows that the features suggested in this study are useful to detect OSA.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.2
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• pp.75-80
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• 2020

There are so many low power MAC protocols for wireless sensor network. IEEE802.15.4 among them has disadvantage of a large power consumption for synchronization. To save power consumption it use the superframe operation alternating sleep mode and awake mode. But latency is longer result from superframe operation. B-MAC can have shorter latency according to check interval. But transmitter consumes more power because of long preamble. And receiver is suffering from overhearing. In this paper, we use the adaptive check interval scheme[1] of B-MAC for enhancing the power consumption. Its maximum throughput and minimum delay is evaluated by comparing the proposed scheme with a typical single channel IEEE802.15.4.

• Journal of Digital Convergence
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• v.14 no.7
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• pp.225-232
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• 2016

This paper aimed to study on the relevance of mental health and oral health. The subjects were recruited total 3,261 elderly of over 40 years old, using the Sixth Korea National Health and Nutrition Examination Survey(KNHANES). All the collected data were analyzed by chi-square test, t-test, and logistic regression using SPSS 23.0 version. Logistic regression was used to analyze the relationship of sleeping time or stress and the number of remaining teeth, and 95% confidence intervals were computed. Sleeping time odds ratio(OR) of the number of remaining teeth was 1.52 (95% confidence interval: 1.074-2.135) and Stress odds ratio(OR) was 2.39 (95% confidence interval: 1.855-3.090), but there is no statistically significant difference after adjusted age, gender and other variables.

• Journal of Oral Medicine and Pain
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• v.39 no.1
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• pp.10-14
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• 2014

Purpose: The aim of this study is to evaluate the difference between gustatory functions in a sleep disordered breathing (SDB) group and a control group. The pathogenesis of SDB has not been fully understood. Though the precise contributions of neuromuscular and anatomical factors on SDB pathogenesis are still debated, we hypothesized that the gustatory dysfunction could be predisposed to SDB. Methods: All patients were diagnosed as SDB by polysomnography (PSG). On the basis of PSG results, patients were divided into 3 groups: snoring, mixed, and obstructive sleep apnea (OSA). The control group comprised healthy volunteers who were the same age as those of the SDB group and whose breathing was verified as normal using a portable sleep monitor device. The patient group and the control group were evaluated for gustatory functions with an electrogustometry (EGM). The electrical taste thresholds were measured in the anterior, midlateral, and posterior sides of the tongue and soft palatal regions, both sides. To find out the difference in EGM scores, statistical analysis was performed using the Kruskal-wallis and Mann-Whitney U test with 95% confidence interval and p<0.05 significance level. Results: The patients with SDB had higher EGM scores than the control group at all spots tested, except for the right midlateral of the tongue, and there was a statistical significance in the comparison between the control group and the divided SDB groups, respectively. Among the divided SDB groups, the snoring group had the most significant differences in the number of the measured spots, but there was no difference among the snoring, mixed, and OSA groups. Conclusions: These results may suggest that neurologic alterations with sleep disordered breathing could be associated with gustatory dysfunction. In the future, further systemic studies will be needed to confirm this study.

• Journal of Biomedical Engineering Research
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• v.35 no.4
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• pp.95-98
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• 2014

The baroreflex is one kind of homeostatic mechanisms to regulate acute blood pressure (BP) changes by controlling heartbeat interval (HBI). To quantify the effect of baroreflex, we suggested a new approach of analyzing Granger causality between systolic BP (SBP) and HBI. The index defined as baroreflex effectiveness (BRE) was generated by the hypothesis that more effectual baroreflex would be related to more effective Granger causal influence of SBP on HBI. Six obstructive sleep apnea (OSA) patients (apnea-hypopnea index, AHI ${\geq}5$ events/hr) and six normal subjects participated in the study. Their SBP and HBI during nocturnal sleep were obtained from a non-invasive continuous BP measurement device. While the BRE ($mean{\pm}SD$) of normal subjects was $47.0{\pm}4.0%$, OSA patients exhibited the BRE of $34.0{\pm}3.8%$. The impaired baroreflex function of OSA patients can be explained by the physiological mechanism associated with recurrent hypoxic episodes during sleep. Thus, the significantly lower BRE in OSA patients verified the availability of Granger causality analysis to evaluate baroreflex during sleep. Furthermore, the range of BRE obtained from normal subjects was not overlapped with that obtained from OSA patients. It suggests the potential of BRE as a new helpful tool for diagnosing OSA.

• Journal of Sleep Medicine
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• v.15 no.2
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• pp.48-54
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• 2018

Objectives: The aim of this study was to develop a predicting model for the optimal continuous positive airway pressure (CPAP) for obstructive sleep apnea (OSA) patient with obesity by using a machine learning. Methods: We retrospectively investigated the medical records of 162 OSA patients who had obesity [body mass index (BMI) ≥ 25] and undertaken successful CPAP titration study. We divided the data to a training set (90%) and a test set (10%), randomly. We made a random forest model and a least absolute shrinkage and selection operator (lasso) regression model to predict the optimal pressure by using the training set, and then applied our models and previous reported equations to the test set. To compare the fitness of each models, we used a correlation coefficient (CC) and a mean absolute error (MAE). Results: The random forest model showed the best performance {CC 0.78 [95% confidence interval (CI) 0.43-0.93], MAE 1.20}. The lasso regression model also showed the improved result [CC 0.78 (95% CI 0.42-0.93), MAE 1.26] compared to the Hoffstein equation [CC 0.68 (95% CI 0.23-0.89), MAE 1.34] and the Choi's equation [CC 0.72 (95% CI 0.30-0.90), MAE 1.40]. Conclusions: Our random forest model and lasso model ($26.213+0.084{\times}BMI+0.004{\times}$apnea-hypopnea index+$0.004{\times}oxygen$ desaturation index-$0.215{\times}mean$ oxygen saturation) showed the improved performance compared to the previous reported equations. The further study for other subgroup or phenotype of OSA is required.