• Journal of the Korea Convergence Society
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• v.9 no.1
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• pp.387-392
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• 2018

The aim of this study was to determine the statistical significance of heart rate variability(HRV) between sleep stages, Apnea-hypopnea index(AHI) and age in patients with obstructive sleep apnea(OSA). This study evaluated the main parameters of HRV over time domain and frequency domain in 40 patients with sleep apnea. The non-REM(sleep stage) was statistically validated by comparing the AHI degree of the three groups(mild, moderate, severe) of sleep apnea patients. The NN50(p=0.043), pNN50(p=0.044), VLF peak(p=0.022), LF/HF(p=0.028) were statistically significant in the R-R interval of patients with sleep apnea from the control group (p<0.05). The LF / HF (p = 0.045) and HF power (p = 0.0395) parameters between the non-RAM sleep (sleep 2 phase) and REM sleep in patients with sleep apnea were statistically significant in the control group(p<0.05). We may be able to provide a basis for understanding the correlation among AHI, sleep stage and age and heart rate variability in patients with obstructive sleep apnea.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.131-132
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• 2008

본 연구에서는 백서(SD rat)을 통하여 출혈량을 제어하여, 일정만 프로토클 내에서 통합 시스템으로 생리적 데이터를 획득하고, 출혈량에 따른 생리적 변화를 관찰하는데 목적이 있나 외상 환자의 사망 원인 중에서 높이 차지하고 있는 출혈성 쇼크의 효과석인 조기 피로 및 치료 효과 예후의 객관적 판정에 도움을 주고자, 컨트롤이 용이한 백서 11마리로부터 출혈성 쇼크와 상관관계가 높다고 알려진 자율 신경계의 생체 신호 변화 특성인 심전도, 혈압, 체온, 호흡 등의 계측 방법으로 측정하고 정량적으로 분석하였다. 그 결과 출혈전과 출혈중, 출혈후 각각의 생체 신호 변화를 살펴보았으며, 호흡수와 심박수, 심박변이도의 변화를 알 수 있었다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.641-642
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• 2006

The purpose of this work is to investigate the effect of work load on heart rate variability (HRV) which is widely used marker of the autonomic nervous system activity. Average heart rate, rating of perceived exertion, and the power spectrum of heart rate variability were investigated in seven healthy males during exercise at various work loads. The subjects were divided into two groups according to the average heart rate during exercise, group 1 with lower heart rate and group 2 with higher heart rate. HF component showed decrease followed by increase with workload. Accordingly, the LF/HF ratio showed increase followed by decrease with workload. The peak in LF/HF ratio of group 1 was at the lower workload than that of group 2.

• Annals of Clinical Neurophysiology
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• v.16 no.2
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• pp.49-54
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• 2014

Heart rate variability is significantly associated with cardiovascular complications in various neurological disorders with cardiac impairment. Measures of spontaneous heart rate variability might be different from provocating tests of heart rate variability such as deep breathing and Valsava maneuver. Methods for analysis are divided into time domain methods and frequency domain methods. There are standard deviation of NN interval, standard deviation of average NN interval, root mean square of the successive differences, NN50, and pNN50 in time domain methods. Frequency domain bands can be divided into very low, low, and high frequency. Each variables are influenced by sympathetic and/or parasympathetic activity.

• Journal of the Korean Society of Radiology
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• v.12 no.3
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• pp.321-328
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• 2018

The purpose of this study was to investigate factors affecting the heart rate, to analyze the relevance and to use it as a management index of factors of increase in heart rate. A total of 204 adults from November, 2016 to March, 2017 who responded to a personal questionnaire among the adults who underwent coronary computed tomography scans for health screening, were the target of the investigation. In the study, there was a statistically significant difference (p <.05) between the heart rate and the gender, CACS, Stenosis and the forces affecting cardiovascular disease. CACS, Stenosis had a statistically significant difference (p <.05) compared with the other groups in the group with a heart rate of 80 bpm or more, the ability to influence cardiovascular disease was different from that of other groups There was a meaning difference in the heart rate below 60 bpm group compared (p <.05). In conclusion, it is important and desirable to maintain heart rate below 60 bpm in order to prevent having cardiovascular disease history, and below 80 bpm to prevent CACS and stenosis.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.1
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• pp.1-9
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• 2009

In this paper, a 2.4 GHz doppler radar system consisting of a doppler radar sensor and a baseband module were designed to detect heart beat and respiration signal without direct skin contact. The doppler radar system emits RF signal of 2.4 GHz toward human chest, and then detects phase modulation of the reflected signal so as to investigate cardiopulmonary activities. The heartbeat and respiration signals acquired from I/Q channels of the doppler radar system are applied to the pre-processing circuit, the amplification circuit, and the offset circuit of the baseband module. The designed system was tested on mouse, rabbit and mankind, which have different range of heart rates and respiration signals, to evaluate detection accuracy of the system. ECG acquisition system and respiration transducer were used to generate the reference signal. In our experiments, a performance of detection were found to be high in the case that the subject stays still. In this paper, we confirmed that non-contact heart beat and respiration detection using the doppler radar has the possibility and limitation according to distance, cardiopulmonary activities, range of heart rates and respiration.

• Korean Journal of Psychosomatic Medicine
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• v.21 no.1
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• pp.55-61
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• 2013

Objectives : Alzheimer's disease(AD) and mild cognitive impairment(MCI) affect several nervous structures involved with the autonomic nervous system. Association between neuropsychiatric deficits and heart rate variability has been observed. But cardiac autonomic function in AD has been scarcely studied and the results reported are conflicting. We investigated autonomic function in normal control, MCI, AD using heart rate variability(HRV) technique. Methods : Time and frequency-domain variability of 5-min R-R interval series was comparatively evaluated in 26 normal control subjects, 22 MCI subjects and 34 AD subjects. Analysis of variance(ANOVA) was used to compare the differences across groups. Correlations between MMSE-KC and HRV components were performed using Pearson's correlation coefficient. Results : No significant difference was observed among the groups in time, frequency-domain analysis of HRV(p>0.05). HRV were not found to be significantly correlated with the degree of cognitive impairment. Conclusions : There were no differences in HRV with MCI, AD subjects when compared with normal controls. Further investigation is required to use HRV technique as noninvasive parameters of MCI and AD.

• Korean Journal of Psychosomatic Medicine
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• v.28 no.1
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• pp.81-88
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• 2020

Objectives : This study aimed to compare autonomic nervous system (ANS) dysregulation and differential relationships with clinical severities between anxiety disorder, depressive disorder, and trauma·stressor related disorder using heart rate variability (HRV) parameters. Methods : We conducted a retrospective chart review of outpatients from 2017 to 2018 in Stress Clinic of National Center for Mental Health. Total 473 patients were included; 166 anxiety disorder; 184 depressive disorder ; 123 trauma·stressor related disorder. Parameters of 5-min analysis of HRV were compared in three groups. Additionally, we investigated the differential association of each parameters with Clinical Global Impression-Severity Scale (CGI-S) across each group. Results : No significant differences were found in all HRV parameters between the three groups. However, significant group interactions by CGI-S were found in standard deviation of all RR intervals (SDNN) and the square root of the mean squared differences of successive normal-to-normal intervals (RMSSD) (SDNN, p=0.017 ; RMSSD, p=0.034). A negative relationship between CGI-S and SDNN, RMSSD has been found in anxiety disorder and depressive disorder. However, a positive relationship between CGI-S and SDNN, RMSSD has been found in trauma·stressor related disorder. Conclusions : Despite of no significant differences of each HRV parameter, our findings suggested the differential associations of HRV parameters with clinical severity among anxiety disorder, depressive disorder and trauma·stressor related disorder. In trauma·stressor related disorder, the clinical severity and degree of ANS dysregulation may differ, so more aggressive treatment is suggested.

• Science of Emotion and Sensibility
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• v.20 no.3
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• pp.169-180
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• 2017

Individuals with high trait anxiety try to suppress their anger expression, thus there are limits in measuring their anger using subjective behavioral evaluation. In order to overcome this limitation, this study attempted to identify the difference in the autonomic nervous system responses induced by anger in individuals with high trait anxiety. Participants were divided into two groups, anxiety and control groups. Electrocardiogram (ECG), respiration (RESP), electrodermal activity (EDA), and skin temperature (SKT) were measured while participants were presented with an anger-inducing stimulus. Heart rate (HR), standard deviation of NN interval (SDNN), root mean square of successive difference (RMSSD), low frequency (LF), high frequency (HF), LF/HF ratio, respiration rate (RR), skin conductance level (SCL), and maximum skin temperature (maxSKT) were calculated before and after presenting the stimulus. Anxiety group reported greater anger by the anger-inducing stimulus compared to the control group. Anxiety group also showed significant increase in SDNN and LF, and decrease in HF, LF/HF ratio, and RR. These results suggest that the autonomic nervous system responses may be used as objective indicators of anger experiences in individuals with high trait anxiety.

• Journal of the Korea Society of Computer and Information
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• v.15 no.10
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• pp.105-112
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• 2010

In this paper, the bio-signals, such as EEG, ECG were measured with a sensor and their characters were drawn out and analyzed. With results from the analysis, four emotion of rest, concentration, tension and depression were inferred. In order to assess one's emotion, the characteristic vectors were drawn out by applying various ways, including the frequency analysis of the bio-signals like the measured EEG and HRV. RBFN, a neural network of the complex structure of unsupervised and supervised learning, was applied to classify and infer the deducted information. Through experiments, the system suggested in this thesis showed better capability to classify and infer than other systems using a different neural network. As follow-up research tasks, the recognizance rate of the measured bio-signals should be improved. Also, the technology which can be applied to the wired or wireless sensor measuring the bio-signals more easily and to wearable computing should be developed.