• Sleep Medicine and Psychophysiology
• /
• v.14 no.2
• /
• pp.86-91
• /
• 2007

Background: Actigraphy is a reliable and valid method for assessing sleep in normal, healthy populations, but it may be less reliable and valid for detecting disturbed sleep in patients. In this study, we attempted to assess the utility of actigraphy in the estimation of sleep quality in patients with obstructive sleep apnea syndrome (OSAS), a major sleep disorder. Method: We analyzed the data of patients who underwent polysomnography (PSG) and actigraphy simultaneously for one night at the Center for Sleep and Chronobiology, Seoul National University Hospital from November 2004 to March 2006. Eighty-nine subjects with OSAS alone and 21 subjects with OSAS and periodic limb movement disorder (PLMD) were included for final data analyses between groups. Polysomnographic and actigraphic data were also compared. Results: In subjects with mild OSAS (RDI<15), modretae ($15{\leq}RDI$<30), and OSAS with PLMD, PSG and actigraphy did not show significant difference in total sleep time and sleep efficiency. However in severe ($30{\leq}RDI$) OSAS subjects, PSG and actigraphy showed significant difference in total sleep time and sleep efficiency. In all patients, no correlations were found between sleep parameters from PSG and from those using actigraphy. Conclusions: We suggest that in severe OSAS patients, PSG is the diagnostic tool. In mild and moderate cases, actigraphy might be used as a screening tool.

• Sleep Medicine and Psychophysiology
• /
• v.14 no.2
• /
• pp.92-98
• /
• 2007

Objectives: Obstructive sleep apnea syndrome (OSAS) is the most common form of sleep-disordered breathing and often presents with comorbid depressive symptoms. In this study, we evaluated the relationship between depressive symptoms and sleep parameters as measured by nocturnal polysomnography (NPSG) and simultaneous wrist actigraphy. Methods: Two hundred sixty-four subjects with clinically suspected cases of OSAS underwent one-night polysomnography, while simultaneously wearing a wrist actigraphy device. They also completed two questionnaires；the Epworth Sleepiness Scale-Korean version (ESS-K) and the Beck Depression Inventory (BDI). Of the cases studied, 105 subjects were proven by NSPG to have OSAS without other sleep disorders. NPSG and wrist actigraphy data from the subjects were analyzed. Pearson correlation and paired t-test were used in order to evaluate the relationship between depressive symptoms and sleep-parameters. Results: Mean age of the subjects was $46.1{\pm}13.1$ years. Means of the ESS-K score and BDI scores were $10.9{\pm}4.7$ and $12.8{\pm}8.1$, respectively. NPSG sleep parameters significantly differed from those of wrist actigraphy. There was no correlation found between subjects' respiratory disturbance index (RDI) and BDI scores. When directly comparing sleep parameters between subjects who were more depressed versus subjects who were less depressed, both total sleep time and sleep efficiency were decreased in the more depressed. A correlation between RDI and ESS-K scores was also found in the more depressed group. Conclusions: Although our findings suggest that there is no relationship between RDI and depressive symptoms, there are other significant differences in the sleep parameters between subjects who are more depressed versus those without depression. We recommend that patients with depression should also be evaluated for clinical symptoms of OSAS.

• Korean Journal of Psychosomatic Medicine
• /
• v.25 no.2
• /
• pp.166-175
• /
• 2017

Objectives: Shiftwork is known to be one of the common causes of sleep and health problems and finally causes the decreased quality of life. The purpose of this study was to investigate the sleep patterns of shift-working and daytime psychiatric nurses using actigraphy and compare it with subjective assessment for sleep. Methods : Twenty-three shift-working and 25 daytime nurses were enrolled. They rated their sleep quality using Pittsburgh Sleep Quality Index(PSQI) and other self-rating scales were measured for psychosocial aspects. Actigraphy was applied to the subjects for a total of 7 days to measure the sleep parameters. They also wrote sleep diaries during the period of wearing actigraphy. Sleep-related parameters of actigraphy, global score and components of PSQI, and the results of other self-rating scales were compared between shift-working and daytime nurses. Results : Although the global score of PSQI did not show significant difference, the PSQI components showed significant differences between two groups: the shift-working nurses showed lower sleep quality, more sleep disturbance and hypnotic medication use, and worsened daytime dysfunction than daytime nurses. The shift-working nurses showed significantly shorter total time in bed and total sleep time, lower sleep efficiency, and longer average awakening time than those of daytime nurses in actigraphy. Conclusions : The results showed that shift-working nurses experienced more sleep disturbances in both subjective and objective aspects of sleep than daytime nurses. This study also suggests that actigraphy may be useful to measure the objective aspects of sleep that are difficult to assess with subjective questionnaires alone.

• Journal of the Korea Convergence Society
• /
• v.9 no.11
• /
• pp.83-90
• /
• 2018

Recently, many people have suffered from insomnia, labor loss, cognitive decline, and mental illness. The solution to this problem is almost entirely cognitive therapy or medication, but it is not recommended in the long term due to side effects and dependency problems. Therefore, in this paper, we propose a neuro feedback system based on portable EEG that helps induce sleeping. We design and evaluate the EEG classifier, which is the most important function to implement the system, and propose an optimized classifier modeling method for various factors that can affect performance. When using the proposed classifier, we could distinguish 97.9% of awakening and sleep phase in portable EEG.

• Sleep Medicine and Psychophysiology
• /
• v.12 no.1
• /
• pp.39-44
• /
• 2005

Objectives: Much attention has been paid to sleep apnea syndrome (SAS) in the elderly because of its high prevalence. It is expected that SAS in the elderly has both similarities and differences compared to SAS in the young or middle-aged populations. The aim of this study was to elucidate the characteristics and consequences of SAS in the elderly. Methods: In this study we included 210 young or middle-aged adults between 23 and 59 years (20 women and 190 men) and 65 older adults between 60 and 83 years of age (16 women and 49 men). Respiratory disturbance indices (RDIs) of the study subjects were more than 5 in an overnight polysomnography. They completed the Epworth Sleepiness Scale (ESS) and Pittsburgh Sleep Quality Index (PSQI). Informations about body mass index (BMI), neck, waist, and hip measurements, and blood pressure were obtained. Results: No difference was observed between older adults with SAS (older SAS) and adults aged under 60 with SAS (SAS aged under 60) in RDI, apnea index, % time of oxygen saturation less than 90%, and PSQI. Obstructive apnea index and oxygen desaturation index (ODI) were lower in older SAS. Compared to SAS aged under 60, lowest oxygen saturation and central apnea index were higher in older SAS, but they were statistically not significant. BMI and neck circumference were significantly lower in older SAS compared to SAS aged under 60. Diastolic blood pressure was lower in older SAS compared to SAS aged under 60 with no difference in systolic blood pressure. Older SAS showed lower scores in ESS than SAS aged under 60. Significant correlation was observed between RDI and BMI in SAS aged under 60, but not in the case of older SAS. The relationships between RDI and neck circumference, systolic and diastolic pressure, and ESS were similar. Conclusions: The elderly with SAS were not over-weight and there was no relationship between body weight and the severity of SAS. Also, the behavioral and cardiovascular effects of SAS were not marked in the elderly, which might be partly explained by decreased ODI and relatively higher lowest oxygen saturation in older SAS. The normal aging process, aside from increased body weight, might contribute to the development of SAS in the elderly with modest complications.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.6
• /
• pp.126-134
• /
• 2015

A sleep disorder is being recognized as one of the major health issues related to high levels of stress. At the same time, interests about quality of sleep are rapidly increasing. However, diagnosing sleep disorder is not a simple task because patients should undergo polysomnography test, which requires a long time and high cost. To solve this problem, an accelerometer embedded wrist-worn device is being considered as a simple and low cost solution. However, conventional methods determine a state of user to "sleep" or "wake" according to whether values of individual section's accelerometer data exceed a certain threshold or not. As a result, a high miss-classification rate is observed due to user's intermittent movements while sleeping and tiny movements while awake. In this paper, we propose a novel method that resolves the above problems by employing a dynamic classifier which evaluates a similarity between the neighboring data scores obtained from SVM classifier. A performance of the proposed method is evaluated using 50 data sets and its superiority is verified by achieving 88.9% accuracy, 88.9% sensitivity, and 88.5% specificity.

• Sleep Medicine and Psychophysiology
• /
• v.2 no.1
• /
• pp.73-81
• /
• 1995

Objective : Patients with sleep apnea should be diagnosed with polysomnography(PSG). However, it is not easy to recommend PSG for all patients suspected with sleep apnea in practice. Therefore, we tried to develop the screening test for referral of PSG. Method : 140 patients with snoring and sleep apnea syndrome were studied by the PSG. Sleep apnea questionnaire. Zung's scale for depression. Stanford Sleepiness Scale(SSS), insomnia scale and neuropsychological test were administered. Also, blood pressure, height, weight and neck circumference were measured and some histories were taken. Correlations between respiratory disturbance index(RDI) and various parameters mentioned above and discriminant coefficients of the parameters to RDI were computed. And, we investigated sensitivities of screening tests for selection of the patients with RDI above 20. Results : Using six parameters(neck circumference, systolic blood pressure before sleep, degree of alcohol drinking, frequency of breath-holding during sleep, degree of dry mouth during sleep, sleep apnea score), the patients with RDI above 20 could be discriminated in 92.8% sensitivity. In case of more than two among six parameters(neck circumference of above 40cm, systolic blood pressure of above 125mmHg, frequent alcohol drinking, frequent breath-holding during sleep, frequent dry mouth during sleep, sleep apnea score of above 35), same patients could be discriminated in 87.6% sensitivity. And, in case of more than one among four parameters(neck circumference of above 40cm. systolic blood pressure of above 125mmHg, frequent alcohol drinking, body weight of above 80kg), discrimination sensitivity was 83.5%. Conclusions : Patients with RDI above 20 could be discriminated by above parameters with high sensitivity. Therefore, the screening test using above parameters can be applied in selection of the patients with sleep apnea for PSG in practice.

• Sleep Medicine and Psychophysiology
• /
• v.9 no.1
• /
• pp.24-33
• /
• 2002

Objectives: Nasal continuous positive airway pressure (CPAP) corrected elevated blood pressure (BP) in some studies of obstructive sleep apnea syndrome (OSAS) but not in others. Such inconsistent results in previous studies might be due to differences in factors influencing the effects of CPAP on BP. The factors referred to include BP monitoring techniques, the characteristics of subjects, and method of CPAP application. Therefore, we evaluated the effects of one night CPAP application on BP and heart rate (HR) reactivity using non-invasive beat-to-beat BP measurement in normotensive and hypertensive subjects with OSAS. Methods: Finger arterial BP and oxygen saturation monitoring with nocturnal polysomnography were performed on 10 OSAS patients (mean age $52.2{\pm}12.4\;years$; 9 males, 1 female; respiratory disturbance index (RDI)>5) for one baseline night and another CPAP night. Beat-to-beat measurement of BP and HR was done with finger arterial BP monitor ($Finapres^{(R)}$) and mean arterial oxygen saturation ($SaO_2$) was also measured at 2-second intervals for both nights. We compared the mean values of cardiovascular and respiratory variables between baseline and CPAP nights using Wilcoxon signed ranks test. Delta ($\Delta$) BP, defined as the subtracted value of CPAP night BP from baseline night BP, was correlated with age, body mass index (BMI), baseline night values of BP, BP variability, HR, HR variability, mean $SaO_2$ and respiratory disturbance index (RDI), and CPAP night values of TWT% (total wake time%) and CPAP pressure, using Spearman's correlation. Results: 1) Although increase of mean $SaO_2$ (p<.01) and decrease of RDI (p<.01) were observed on the CPAP night, there were no significant differences in other variables between two nights. 2) However, delta BP tended to increase or decease depending on BP values of the baseline night and age. Delta systolic BP and baseline systolic BP showed a significant positive correlation (p<.01), but delta diastolic BP and baseline diastolic BP did not show a significant correlation except for a positive correlation in wake stage (p<.01). Delta diastolic BP and age showed a significant negative correlation (p<.05) during all stages except for REM stage, but delta systolic BP and age did not. 3) Delta systolic and diastolic BPs did not significantly correlate with other factors, such as BMI, baseline night values of BP variability, HR, HR variability, mean SaO2 and RDI, and CPAP night values of TWT% and CPAP pressure, except for a positive correlation of delta diastolic pressure and TWT% of CPAP night (p<.01). Conclusions: We observed that systolic BP and diastolic BP tended to decrease, increase or remain still in accordance with the systolic BP level of baseline night and aging. We suggest that BP reactivity by CPAP be dealt with as a complex phenomenon rather than a simple undifferentiated BP decrease.

• Journal of Digital Convergence
• /
• v.15 no.9
• /
• pp.311-319
• /
• 2017

The purpose of this study was to examine the relationship between hours of sleep and periodontal diseases among adolescents based on the raw materials of the 5th third-year(2012) national health and nutrition examination survey. The subjects in this study were 593 selected teens who were at the western ages of 12 to 18. SPSS 18.0 for Windows was used to analyze general characteristics, health behavior, oral health care, mental health, and relationship of sleep duration to periodontal disease. As a result, the groups of adolescents who were older and whose household income was larger slept for less hours, and higher toothbrushing frequencies led to more hours of sleep. There were 2.28-fold more periodontal diseases in the group that got five or less hours of sleep than in the group that got eight or more hours of sleep. The above-mentioned findings of the study illustrated that insufficient sleep is linked to periodontal health in adolescence.

• Sleep Medicine and Psychophysiology
• /
• v.1 no.2
• /
• pp.163-171
• /
• 1994

Objectives: Symptoms of sleep apnea consisted of insomnia, excessive sleepiness during daytime, impaired cognitive functions and emotional disturbances. It was not so well known how these symptoms are correlated with various parameters of sleep and respiration, and what kind of psychophysiological processes are involved in development of these symptoms. Methods: In sixty patients with sleep apnea, sleep and respiration were studied by polysomnography of one night, also symptoms of sleep apnea were evaluated with the scales of insomnia, daytime sleepiness, emotional disturbance and cognitive impairment We studied correlations between apnea symptoms, and various parameters of sleep and respiration such as sleep efficiency, number severity of apnea, $O_2$ desaturation and number of snoring. Results: The result showing significant correlations are as follows. The patients with better sleep in insomnia scale showed more number of apnea, particularly more central type, and much more snoring in stage 3 sleep and mild desaturation of $O_2$. Excessive sleepiness during daytime correlated significantly with stage 1 sleep and its snoring, but correlated negatively with stage 2 sleep. However, no significant correlation was found with degree of $O_2$ desaturation. Emotional disturbance was more apparent in the patients with severe $O_2$ desaturation and smaller amounts of stage 4 sleep. Cognitive function was more impaired in cases of more REM sleep and less apnea. Conclusions: Symptoms of sleep apnea may occur through different causes and processes. The evaluation of apnea symptoms may be helpful to understand in some degree the condition of sleep and respiration during sleep in clinical setting.