• Korean Journal of Oriental Medicine
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• v.13 no.3
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• pp.97-103
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• 2007

The object of this study is to evaluate confounding effect of sleeping behavior on heart rate variability (HRV) in healthy volunteers during a randomized clinical trial. From 6 healthy volunteer, we acquired circadian electrocardiography(ECG) with a Holter monitoring device(DigiTrak Plus, Philips). The compatible analytical program, Zymed, was used for calculation of RR intervals of 24h ECG signal. Then, we generated HRV signals and calculated 9 HRV parameters in time domain and frequency domain for every 30 minute with Matlab 6.x software. We also encoded participants' activities as follows; stable condition(1), sleeping behavior(2), eating behavior(3), and undefined condition(4). Using SPSS 12.0, we tested if there was any difference between HRV parameters of day-time and night-time and between those of a subject in stable condition and in sleeping behavior. As a result, one of the most important parameter-LF/HF ratio, which indicates the autonomic balance between sympathetic and parasympathetic nervous systems, as same the other parameters, showed large inter-individual variations in circadian profiles. And, the mean LF/HF ratio of each participant was different between in stable condition and in sleeping behavior (p<.05). Consequently, the effect of sleeping behavior must be considered when one or more of HRV parameters, especially LF/HF ratio, are used as assessment index in clinical studies.

• The KIPS Transactions:PartD
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• v.16D no.1
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• pp.11-26
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• 2009

In order to diagnose cardiovascular disease, we proposed EP-based(emerging pattern- based) classification technique using multi-parametric diagnosis indexes. We analyzed linear/nonlinear features of HRV for three recumbent postures and extracted four diagnosis indexes from ST-segments to apply the multi-parametric diagnosis indexes. In this paper, classification model using essential emerging patterns for diagnosing disease was applied. This classification technique discovers disease patterns of patient group and these emerging patterns are frequent in patients with cardiovascular disease but are not frequent in the normal group. To evaluate proposed classification algorithm, 120 patients with AP (angina pectrois), 13 patients with ACS(acute coronary syndrome) and 128 normal people data were used. As a result of classification, when multi-parametric indexes were used, the percent accuracy in classifying three groups was turned out to be about 88.3%.

• The Journal of Korean Obstetrics and Gynecology
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• v.30 no.3
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• pp.54-64
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• 2017

Objectives: The purpose of this study is to demonstrate Heart Rate Variability characteristics of menopausal patients with insomnia. Methods: From March 1, 2014 to June 20, 2017, Heart Rate Variability was measured in 102 menopausal patients who visited Cheonan Korean Medicine Hospital of Daejeon University. We compared accompanying symptoms and Heart Rate Variability values depending on sleep quality in menopausal women. Results: The accompanying symptoms of menopausal patients were as follows: hot flushes (45.1%), tiredness (25.49%), chest discomfort and palpitations (23.53%), headache (17.65%), arthralgia and muscular pain (17.65%), cold sensitivity of hands and feet (15.69%), urinary frequency (14.71%) and anxiety (10.78%). The frequency of chest discomfort and palpitation was significantly higher in the menopausal insomnia group than in normal sleep group. Comparing Heart Rate Variability between two groups, Standard deviation of the NN interval (SDNN), Total Power (TP), and Low Frequency (LF) values were significantly lower in insomnia group. Conclusions: Chest discomfort and palpitations were more frequent in insomnia patients in menopausal women than normal sleep group, and Standard deviation of the NN interval (SDNN), Total Power (TP), Low Frequency (LF) were significantly lower in HRV values.

• Journal of the Korean Society of School Health
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• v.30 no.3
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• pp.266-273
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• 2017

Purpose: This study was performed to compare the mental health of school age children residing in urban and rural areas and to analyze the correlations between the subjective mental health indicators such as depression and attention deficit-hyperactivity behavior and heart rate variability (HRV) indicators. Methods: For this study, a convenience sample of one hundred and three children was recruited. Depression and attention deficit-hyperactivity behavior were measured using self-reported questionnaires and HRV indicators were measured using an electronic instrument. Results: Among the HRV parameters of the rural children, their normalized LF and the LF / HF were significantly lower than those of the urban children. The RMSSD and the normalized HF were statistically significantly higher. The level of depression showed a significant positive correlation with the normalized LF and LF/HF, but showed a negative correlation with the normalized HF. Also, the level of attention deficit-hyperactivity behavior was significantly correlated with the normalized LF, LF/HF, and the normalized HF. Conclusion: Based on the findings, we expect that HRV indicators can be applied to predict the level of depression and attention deficit-hyperactivity behavior in elementary school children.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.10
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• pp.1427-1434
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• 2021

In this paper, we propose a psychological state estimation process that computes children's attention and tension in response to training stimuli. Joint attention was adopted as the training stimulus required for behavioral intervention, and the Discrete trial training (DTT) technique was applied as the training protocol. Three types of training stimulation contents are composed to check the user's attention and tension level and provided mounted on a character-shaped tabletop robot. Then, the gaze response to the user's training stimulus is estimated with the vision-based head pose recognition and geometrical calculation model, and the nervous system response is analyzed using the PPG and GSR bio-signals using heart rate variability(HRV) and histogram techniques. Through experiments using robots, it was confirmed that the psychological response of users to training contents on joint attention could be quantified.

• The Journal of Internal Korean Medicine
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• v.43 no.1
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• pp.53-67
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• 2022

Objectives: This study aimed to identify the characteristics of the heart rate variability (HRV) index in patients with burning mouth syndrome (BMS) and to evaluate the predictive value of HRV for Korean medical treatment responsiveness to tongue pain in BMS. Methods: Among BMS patients who visited the Oral Diseases Clinic of Kyung Hee University Korean Medicine Hospital from January 1, 2018, to May 31, 2021, we reviewed the clinical records of 217 women aged 50 years and over. HRV and unstimulated saliva flow rate (USFR) measurements were carried out, and all patients were asked to indicate their degree of tongue pain using the visual analog scale (VAS). The subjects were classified into subgroups according to the presence or absence of hyposalivation and VAS improvement, and each subgroup was compared using the HRV index. Logistic regression analysis was conducted to confirm whether cause-effect relationships were present between statistically significant values. Results: BMS patients had lower LF and HF than healthy people. Subgroup analysis demonstrated that there were some statistically significant differences in the HRV index according to salivation rate and degree of pain. In addition, as the LF/HF ratio increased, the pain improvement rate decreased after treatment. Conclusion: The autonomic nerve activity of BMS patients was lower than that of healthy people; however, autonomic balance was not impaired. In addition, tongue pain in BMS patients responded more favorably to Korean medical treatment when patients fell within a normal range of the LF/HF ratio, suggesting that autonomic imbalance could be used as one of the predictable factors in clinical practice.

• Journal of Korean Society of Forest Science
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• v.112 no.4
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• pp.544-553
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• 2023

The purpose of this study was to reveal the thermal comfort and physiological and psychological effects of spending time in broad-leaved forests in suumer. Thirty-one university students (with an average age of 21.4 ± 2.1 years) participated in the study, and a within-subjects experimental design methodology was used. The participants moved to an experimental site (with a crown closure of 76.6%) or a control site (25.9%), sat on a chair to eliminate the impact of movement, and rested for 5 minutes with closed eyes. At this time, thermal comfort, heart rate variability, heart rate, and forehead temperature were continuously measured. After that, blood pressure and pulse rate were measured, and a subjective evaluation was conducted. As a result, spending time at an experimental site showed a statistically significant decrease in the predicted mean vote and the percentage of dissatisfied values, enhancement of parasympathetic nerve activity, decrease of forehead temperature, diastolic blood pressure, heart rate, pulse rate, and improvement of personal thermal sensation (thermal sensation vote and comfort sensation vote). In conclusion, it was found that a forest with high crown closure reduces thermal stress and induces physiological and psychological relaxation.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.2
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• pp.163-170
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• 2016

The purpose of this study was to verify the emotional response of user to LED light colors in healing bed system in cypress tree. Eight colors of LED light were provided including red, orange, yellow, green, blue, indigo, violet and white. And three illumination color temperature were provided including 3,000K, 5,000K, 8,000K. Seven subjects in their twenties were involved without the medical history of eyes and heart disorders. The subjects were exposed to LED lighting during 5 minutes and their emotional response was evaluated through the following: first, at the physiological effect heart rate variability(HRV) was measured during the stimulation; second, at the emotion level the subjects were asked about lighting color and color temperature through a survey. Results, lower color temperature of 3,000K and green color shows high value on HRV. We have found that there is a difference of physiological and emotion level effect depending on color stimulus. This study could be applied to reference data to analysis of a decrease in fatique and charges of brain waves for color stimulus.

• 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 Digital Convergence
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• v.21 no.3
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• pp.33-39
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• 2023

This study is a performance evaluation of a blood sugar monitoring system that combines a PPG sensor, which is an evaluation device for blood glucose monitoring, and a DNN algorithm when monitoring capillary blood glucose. The study is a researcher-led clinical trial conducted on participants from September 2023 to November 2023. PPG-BGMS compared predicted blood sugar levels for evaluation using 1-minute heart rate and heart rate variability information and the DNN prediction algorithm with capillary blood glucose levels measured with a blood glucose meter of the standard personal blood sugar management system. Of the 100 participants, 50 had type 2 diabetes (T2DM), and the average age was 67 years (range, 28 to 89 years). It was found that 100% of the predicted blood sugar level of PPG-BGMS was distributed in the A+B area of the Clarke error grid and Parker(Consensus) error grid. The MARD value of PPG-BGMS predicted blood glucose is 5.3 ± 4.0%. Consequentially, the non-blood-based PPG-BGMS was found to be non-inferior to the instantaneous blood sugar level of the clinical standard blood-based personal blood glucose measurement system.