• Sleep Medicine and Psychophysiology
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• v.17 no.1
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• pp.21-27
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• 2010

Objectives: It is well established that primary insomnia affects the activity of autonomic nervous system. We tried to know how the activity of autonomic nervous system during night sleep changes by analyzing correlation between heart rate variability (HRV) index and the variables related with sleep structure in primary insomnia. Methods: Thirty three subjects (mean age: $36.2{\pm}14.2$ years, male:female=15:18) who were diagnosed with primary insomnia were selected for the study. Nocturnal polysomnography (NPSG) was carried out on each subject and correlation was analyzed between high frequency/low frequency ratio (LF/HF ratio), one of HRV indices and the variables related with sleep structure which were calculated from NPSG. Results: When age and sex were controlled, LF/HF ratio showed negative correlations with slow wave sleep and stage 2 sleep, respectively ($r_p$=-0.43, p=0.01; $r_p$=-0.37, p=0.04). On the other hands LF/HF ratio showed a positive correlation with arousal index ($r_p$=0.65, p<0.001). The activity of autonomic nervous system responded differentially depending on the change of sleep structure in primary insomnia. Especially the increase of arousal index and the decrease of slow wave sleep and stage 2 sleep which are the components of non-REM sleep provoked hyperactivity of sympathetic nervous system. Conclusion: This study suggests that the typical change of sleep structure in primary insomnia can negatively impact on cardiovascular system.

• Korean Journal of Psychosomatic Medicine
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• v.19 no.2
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• pp.74-82
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• 2011

Objective:The aim of this study was to evaluate the relationship between sustained attention deficits in Attention-Deficit/Hyperactivity Disorder(ADHD) children and short-term Heart Rate Variability(HRV) parameters. In addition, we evaluate the relationship between The ADHD rating scale(ARS), the computerized ADHD diagnostic system(ADS) and Parenting stress index- short form(PSI-SF). Methods:This study was performed in the department of children and Adolescent psychiatry, Korea university Guro hospital from august 2008 to January 2009. We evaluated HRV parameters by short-term recordings of 5 minutes. K-ARS and ADS are used for screening and identifying ADHD children. Intelligence was measured using Korean educational Developmental Institute-wechsler Intelligence Scale for Children. The caregivers Complete Parenting Stress Index scale for evaluation parent stress. Results:The low frequency(LF) was significantly correlated with response variability of ADS. However, the other variables of ARS and ADS were not significantly correlated with LF. Hyperactivity subscale of ARS was significantly correlated with parental distress subscale and difficult child subscale of PSI-SF and inattention subscale of ARS was also significantly correlated with dysfunctional interaction and difficult child subscale of PSI-SF. Conclusion:The LF, 0.10-Hz component of HRV is known to measure effort allocation. This study shows that the LF component of HRV is significantly correlated with the response variability of ADS. This means that more severe symptoms of ADHD were correlated with the increase in the LF that means decreased effort allocation. These results also support the clinical usability of HRV in the assessment of ADHD. Furthermore, PSI-SF is correlated with hyperactivity and inattention variables of ARS.

• Korean Journal of Biological Psychiatry
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• v.8 no.1
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• pp.20-36
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• 2001

The debate about whether depressive disorders should be divided into categories or arrayed along a continuum has gone for decade, without resolution. In our review, there is more evidence consistent with the spectrum concept than there is with the idea that depressive disorders constitute discrete clusters marked by relatively discontinuous boundaries. First, "depression spectrum", "is there a common genetic factors in bipolar and unipolar affective disorder", "threshold model of depression" and "bipolar spectrum disorder" are reviewed. And, a new subtype of depression is so called SeCA depression that is a stressor-precipitated, cortisol-induced, serotonin-related, anxiety/aggression-driven depression. SeCA depression is discussed. But, there is with the idea that depressive disorders constitute discrete subtypes marked by relatively discontinuous boundaries. This subtypes of depressive disorder were reviewed from a variety of theoretical frames of reference. The following issues are discussed ; Dexamethasone suppression test(DST), TRH stimulation test, MHPG, Temperament Character Inventory(TCI), and heart rate variability(HRV).

• Journal of Biomedical Engineering Research
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• v.25 no.6
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• pp.565-573
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• 2004

In this paper, we proposed a heart activity control model for simulation of the aortic sinus baroreceptor, which was the most representative baroreceptor sensing the variance of pressure in the cardiovascular system. And then, the heart activity control model composed electric circuit model of the cardiovascular system with baroreflex control and time delay sub-model to observe the effect of time delay in heart period and stroke volume under the regulation of baroreflex in the aortic sinus. The mechanism of time delay in the heart activity baroreflex control model is as follows. A control function is conduct sensing pressure information in the aortic sinus baroreceptor to transmit the efferent nerve through central nervous system. As simulation results of the proposed model, we observed three patterns of the cardiovascular system variability by the time delay. First of all, if the time delay over 2.5 second, aortic pressure and stroke volume and heart rate was observed non-periodically and irregularly. However, if the time delay from 0.1 second to 0.25 second, the regular oscillation was observed. And then, if time delay under 0.1 second, then heart rate and aortic pressure-heart rate trajectory were maintained in stable state.

• Sleep Medicine and Psychophysiology
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• v.25 no.1
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• pp.15-20
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• 2018

Objectives: This study was designed to assess the change of heart rate variability (HRV) at resting, upright, and psychological stress states in depressive disorder patients. Methods: HRV was measured at resting, upright, and psychological stress states in 62 depressive disorder patients. We used visual analogue scale (VAS) score to assess tension and stress severity. Beck depression inventory (BDI) and state trait anxiety inventories I and II (STAI-I and II) were used to assess depression and anxiety severity, respectively. Differences between HRV indices and VAS score were evaluated using paired t-tests. Gender difference analysis was conducted with ANCOVA. Results: SDNN (standard deviation of normal to normal intervals), LF/HF (low frequency/high frequency), and VLF (very low frequency) were significantly increased, while NN50 and pNN50 were significantly decreased in the upright position compared to resting state. SDNN, RMSSD (root mean square of the differences of successive normal to normal intervals), and VLF were significantly increased, while pNN50 was significantly decreased in the psychological stress state compared to resting state. SDNN, NN50, and pNN50 were significantly lower in an upright position compared to a state of psychological stress, and LF, HF, and LF/HF showed no significant differences Conclusion: The LF/HF ratio was significantly increased after physical stress in depressive disorder. However, the LF/HF ratio was not significantly increased after psychological stress, and the change in LF/HF ratio after physical stress and psychological stress did not significantly differ from each other. Significant increase in SDNN, NN50, and pNN50 in an upright posture compared to psychological stress suggests that depressive patients react more sensitively to physical stress than psychological stress.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1979-1980
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• 2008

본 논문은 심혈관질환을 예방하기 위한 심박변이도 검사(HRV), 압맥파 검사(PTG), 용적맥파 검사(SDPTG), 사지혈압 검사(BPD), 맥파전달속도 검사(PWV)를 통해 심혈관의 상태를 분석하고 질병을 예방하는데 도움이 될 수 있도록 측정하고 진단 할 수 있는 심혈관 질환에 대한 통합 진단 시스템을 개발하였다. 본 논문에서 개발된 진단 시스템을 통해서 나오는 결과에 대한 소개하였다.

• The Korean Journal of Pain
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• v.19 no.2
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• pp.202-206
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• 2006

Background: Stellate ganglion block (SGB) might be associated with changes in the blood pressure (BP) and heart rate (HR). The heart rate variability (HRV) shows the balance state between sympathetic and parasympathetic activities of the heart. The changes in these parameters of the HRV were studied to evaluate the possible mechanism of SGB in changing the BP. Methods: SGB was performed on 26 patients, using a paratracheal technique at the C6 level, and 8 ml of 1% mepivacaine injected. The success was confirmed by check the Horner's syndrome. The BP, HR and HRV were measured before and 5, 15, 30, 45 and 60 minutes after the SGB. Results: The increases in the BP from the baseline throughout the study period were statistically, but not clinically significant. The HR and LF/HF (low frequency/high frequency) ratio were increased at 5 and 45 min, respectively, after the administration of the SGB. In a comparison of left and right SGB, no significant differences were found in the BP, HR and HRV. A correlation analysis showed that an increased BP was significantly related with the changes in the LF/HF ratio and LF at 15 and 30 minutes, respectively, after the SGB. Dividing the patients into two groups; an increased BP greater and less than 20% of that at the baseline INC and NOT groups, respectively, hoarseness occurred more often in the INC group (P = 0.02). Conclusions: It was concluded that SGB itself does not clinically increase the BP and HR in normal hemodynamic patients. However, the loss of balance between the sympathetic and parasympathetic nerve system, attenuation of the baroreceptor reflex and hoarseness are minor causes of the increase in the BP following SGB; therefore, further studies will be required.

• Korean Journal of Psychosomatic Medicine
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• v.20 no.1
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• pp.59-65
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• 2012

Objectives : The present study takes part of the agricultural district cohort study of a certain county located in Gyeonggido and aims to investigate the difference of the heart rate variability(HRV) according to the social support level. Methods : We used data from 1727 participants of a health promotion program who are older than 40 years old. A physical examination, as well as a one-to-one interview to obtain sociodemographic characteristics, was performed with each participant. In addition, the participants completed the Medical Outcomes Study-Social Support Survey(MOS-SSS) for their the social support level to be assessed, and their HRV were measured to evaluate their autonomic function. The entire group was divided in two groups according to its MOS-SSS points to facilitate the research. Those who were evaluated as the high 25%(432 persons) were denominated as high social support (HSS) group and those who were evaluated as the low 25%(425 persons) were denominated as poor social support(PSS) group. Results : The two groups showed significant differences on the sociodemographic factor such as mean age and gender composition(p<0.05). Comparing the indices related to the HRV, the HSS group had the following values higher than the PSS group : SDNN(F=4.938, p=0.027), TP(F=8.088, p=0.005), VLF(F=6.220, p=0.013) LF (F=3.873, p=0.049). Conclusion : According to the research, the PSS group showed dysfunction on their autonomic nervous system comparing to the HSS group. The social support helps an individual overcome difficulties, helps the adaptation during the changes of circumstances and in stressful situations it serves like a buffer. Based on that, it's possible to define that a low social support level gave an impact on the autonomic function. Also, using the fact that the HRV can evaluate the autonomic function in an objective view, it was possible to visualize that it has a potential to be used as an assistant factor to evaluate the social support.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.4021-4030
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• 2015

Pulse wave is the physiological responses through the autonomic nervous system such as ECG. It is relatively convenient because it can measure the signal just by applying a sensor on a finger. So, it can be usefully employed in the field of U-Healthcare. The objects of this study are acquiring the PPG (Photoplethysmography) one of the way of measuring the pulse waves in non-invasive way using the CMOS image sensor on a smartphone camera, developing the portable system judging stressful or not, and confirming the applicability in the field of u-Healthcare. PPG was acquired by using image data from smartphone camera without separate sensors and analyzed. Also, with that image signal data, HRV (Heart Rate Variability) and stress index were offered users by just using smartphone without separate host equipment. In addition, the reliability and accuracy of acquired data were improved by developing additional hardware device. From these experiments, we can confirm that measuring heart rate through the PPG, and the stress index for analysis the stress degree using the image of a smartphone camera are possible. In this study, we used a smartphone camera, not commercialized product or standardized sensor, so it has low resolution than those of using commercialized external sensor. However, despite this disadvantage, it can be usefully employed as the u-Healthcare device because it can obtain the promising data by developing additional external device for improvement reliability of result and optimization algorithm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.547-554
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• 2014

In this study, have researched 'a' index from three sound sources, effects on subject and finding optimal 'a' index, which can improve subject's stability, concentration and productivity. Check the health status of subjects who were selected 5 male and 5 female university students, and the period of this experiment was about two months. It were measured each subject's EEG, HRV and vibra image to analyze transition of stability, concentration, stress and heart beat. The results was measured in an environmental test room of temperature $25[^{\circ}C]$, the relative humidity 50 [%], illuminance 1,000 [lux] and air current speed 0.02[m/sec] with 'a' index of three sound sources which are a=1.106, a=1.749 and a=2.227. Results in a=1.106 compared to before exposure, relative $S{\alpha}$ wave, relative $L{\beta}$ wave and relative $M{\beta}$ wave have been revitalized, asymmetry index, stress and HRV have been decreased. Thus, to increase stability, concentration and productivity, also to decrease stress, changes in sound source of a=1.106 was found to be the most effective.