• Annals of Clinical Neurophysiology
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• v.13 no.2
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• pp.80-86
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• 2011

Background: A dry-type electrode is an alternative to the conventional wet-type electrode, because it can be applied without any skin preparation, such as a conductive electrolyte. However, because a dry-type electrode without electrolyte has high electrode-to-skin impedance, an impedance-converting amplifier is typically used to minimize the distortion of the bioelectric signal. In this study, we developed an active dry electroencephalography (EEG) electrode using an impedance converter, and compared its performance with a conventional Ag/AgCl EEG electrode. Methods: We developed an active dry electrode with an impedance converter using a chopper-stabilized operational amplifier. Two electrodes, a conventional Ag/AgCl electrode and our active electrode, were used to acquire EEG signals simultaneously, and the performance was tested in terms of (1) the electrode impedance, (2) raw data quality, and (3) the robustness of any artifacts. Results: The contact impedance of the developed electrode was lower than that of the Ag/AgCl electrode ($0.3{\pm}0.1$ vs. $2.7{\pm}0.7\;k{\Omega}$, respectively). The EEG signal and power spectrum were similar for both electrodes. Additionally, our electrode had a lower 60-Hz component than the Ag/AgCl electrode (16.64 vs. 24.33 dB, respectively). The change in potential of the developed electrode with a physical stimulus was lower than for the Ag/AgCl electrode ($58.7{\pm}30.6$ vs. $81.0{\pm}19.1\;{\mu}V$, respectively), and the difference was close to statistical significance (P=0.07). Conclusions: Our electrode can be used to replace Ag/AgCl electrodes, when EEG recording is emergently required, such as in emergency rooms or in intensive care units.

• Journal of Pharmacopuncture
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• v.22 no.3
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• pp.166-170
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• 2019

Objectives: Attentional and memory functions are important aspects of neural plasticity that, theoretically, should be amenable to pharmacopuncture treatments. A previous study from our laboratory suggested that quantitative electroencephalographic (qEEG) measurements of theta/beta ratio (TBR), an index of attentional control, may be indicative of academic performance in a first-semester medical school course. The present study expands our prior report by extracting and analyzing data on frontal theta and beta asymmetries. We test the hypothesis that the amount of frontal theta and beta asymmetries (fTA, fBA), are correlated with TBR and academic performance, thereby providing novel targets for pharmacopuncture treatments to improve cognitive performance. Methods: Ten healthy male volunteers were subjected to 5-10 min of qEEG measurements under eyes-closed conditions. The qEEG measurements were performed 3 days before each of first two block examinations in anatomy-physiology, separated by five weeks. Amplitudes of the theta and beta waveforms, expressed in ${\mu}V$, were used to compute TBR, fTA and fBA. Significance of changes in theta and beta EEG wave amplitude was assessed by ANOVA with post-hoc t-testing. Correlations between TBR, fTA, fBA and the raw examination scores were evaluated by Pearson's product-moment coefficients and linear regression analysis. Results: fTA and fBA were found to be negatively correlated with TBR (P<0.03, P<0.05, respectively) and were positively correlated with the second examination score (P<0.03, P=0.1, respectively). Conclusion: Smaller fTA and fBA were associated with lower academic performance in the second of two first-semester medical school anatomy-physiology block examination. Future studies should determine whether these qEEG metrics are useful for monitoring changes associated with the brain's cognitive adaptations to academic challenges, for predicting academic performance and for targeting phamacopuncture treatments to improve cognitive performance.

• Journal of the Korean Society for information Management
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• v.41 no.1
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• pp.261-282
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• 2024

This study proposed and evaluated electroencephalography (EEG)-based and eye-tracking-based methods to determine relevance by utilizing users' implicit relevance feedback while navigating content in a digital library. For this, EEG/eye-tracking experiments were conducted on 32 participants using video, image, and text data. To assess the usefulness of the proposed methods, deep learning-based artificial intelligence (AI) techniques were used as a competitive benchmark. The evaluation results showed that EEG component-based methods (av_P600 and f_P3b components) demonstrated high classification accuracy in selecting relevant videos and images (faces/emotions). In contrast, AI-based methods, specifically object recognition and natural language processing, showed high classification accuracy for selecting images (objects) and texts (newspaper articles). Finally, guidelines for implementing a digital library interface based on EEG, eye-tracking, and artificial intelligence technologies have been proposed. Specifically, a system model based on implicit relevance feedback has been presented. Moreover, to enhance classification accuracy, methods suitable for each media type have been suggested, including EEG-based, eye-tracking-based, and AI-based approaches.

• Annals of Clinical Neurophysiology
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• v.1 no.1
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• pp.1-9
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• 1999

Since Hans Berger reported the first paper on the human electroencephalogram in 1920s, huge technological advance have made it possible to use a number of electrophysiological approaches to neurological diagnosis in clinical neurology. In majority of the neurology training hospitals they have facilities of electroencephalography(EEG), electromyography(EMG), evoked potentials(EP), polysomnography(PSG), electronystagmography(ENG) and, transcranial doppler(TCD) ete. Clinicials and electrophysiologists should understand the technologic characteristics and general applications of each electrophysiological studies to get useful informations with using them in clinics. It is generally agreed that items of these tests are selected under the clinical examination, the tests are performed by the experts, and the test results are interpretated under the clinical background. Otherwise these tests are sometimes useless and lead clinicians to misunderstand the lesion site, the nature of disease, or the disease course. In this sense the clinical utility of neurophysiological tests could be summerized in the followings. First, the abnormal functioning of the nervous system and its environments can be demonstrated when the history and neurological examinations are equivocal. Second, the presence of clinically unsuspected malfunction in the nervous system can be revealed by those tests. Finally the objective changes can be monitored over time in the patient's status. Also intraoperative monitoring technique becomes one of the important procedures when the major operations in the posterior fossa or in the spinal cord are performed. In 1996, the Korean Society for Clinical Neurophysiology(KSCN) was founded with the hope that it will provide the members with the comfortable place for discussing their clinical and academic experience, exchanging new informations, and learning new techniques of the neurophysiological tests. The KSCN could collaborate with the International Federation of Clinical Neurophysiology(IFCN) to improve the level of the clinical neurophysiologic field in Korea as will as in Asian region.1 In this paper the clinical neurophysiological tests which are commonly used in clinical neurology and which will be delt with and educated by the KSCN in the future will be discussed briefly in order of EEG, EMG, EP, PSG, TCD, ENG, and Intraoperative monitoring.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.8
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• pp.3925-3932
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• 2013

Emotion is closely related to the life of human, so has effect on many parts such as concentration, learning ability, etc. and makes to have different behavior patterns. The purpose of this paper is to extract important features based on physiological signals to recognize negative emotion. In this paper, after acquisition of electrocardiography(ECG), electroencephalography(EEG), skin temperature(SKT) and galvanic skin response(GSR) measurements based on physiological signals, we designed an accurate and fast algorithm using combination of linear discriminant analysis(LDA) and genetic algorithm(GA), then we selected important features. As a result, the accuracy of the algorithm is up to 96.4% and selected features are Mean, root mean square successive difference(RMSSD), NN intervals differing more than 50ms(NN50) of heart rate variability(HRV), ${\sigma}$ and ${\alpha}$ frequency power of EEG from frontal region, ${\alpha}$, ${\beta}$, and ${\gamma}$ frequency power of EEG from central region, and mean and standard deviation of SKT. Therefore, the features play an important role to recognize negative emotion.

• Korean Journal of Biological Psychiatry
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• v.14 no.1
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• pp.42-47
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• 2007

Objectives : Studies have reported differences between depressed adults and controls in quantitative measures of EEG alpha asymmetry, but, there are few using Korean subjects. So, the present study compared EEG regional alpha asymmetries of patients having major depressive disorder(MDD) and normal controls. Methods : The subjects in this study were 11 unmedicated unipolar depressed patients and 11 non-depressed, age matched controls. Resting EEG(eyes closed and eyes open) was recorded from each participant using 8 scalp electrodes. Beck Depression Inventory(BDI), 17-item Hamilton Depression Rating Scale(HDRS), Zung's Self-Rating Depression Scale(SDS) and Spielberger's State-Trait Anxiety Inventory(STAI) were used to evaluate depression and anxiety symptoms. Results : The severities of depression measured by self-report questionnaires were positively associated with those of anxiety(state and trait) ; The subjects were both anxious and depressed. Anxious-depressed patients differed from controls in alpha asymmetry at T4 channels. They showed evidence of greater activation over right than left temporal site. Conclusion : These findings are consistent with the previousely reported alpha asymmetry of depressed patients with an anxiety disorder. The failure to find the evidence of reduced right parietal activity in depression is presumed to be due to opposing effects of comorbid anxiety on parietotemporal activity.

• Science of Emotion and Sensibility
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• v.16 no.1
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• pp.75-84
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• 2013

The underlying changes in biological processes that are associated with reported changes in mental and physical health in response to yoga breathing ($pr{\bar{a}}n{\bar{a}}y{\bar{a}}ma$) have not been systematically explored yet. In this study, the effects of a yoga breathing program on prefrontal EEG were tested with middle-aged women. Participants were collected as volunteers and controlled into two groups. Two channel EEG was recorded in the prefrontal region (Fp1, Fp2) from the yoga breathing group (n=17) and control group (n=17). QEEG quotients were transformed from the EEGs and analyzed by the ANOVAs on gain scores. As a result, ${\alpha}/{\delta}$ (left, right) and CQ (correlation quotient) for yoga breathing participants were significantly decreased compared to control group (p<.05). ${\alpha}/{\beta}_H+{\alpha}/{\delta}$ (left, right) were increased significantly (p<.05). For those significantly changed QEEG quotients, the interaction effects of Group x prefrontal alpha (${\alpha}$) and beta (${\beta}$) asymmetry were tested. Only the ${\alpha}$ asymmetry showed main effect on the gain score of ${\alpha}/{\beta}_H+{\alpha}/{\delta}$ (right) with F (1, 34)＝5.694 (p<.05). Pearson's correlation coefficient between ${\alpha}$ asymmetry and gain score of ${\alpha}/{\beta}_H+{\alpha}/{\delta}$ (right) was .374 (p<.05). The gain score of ${\alpha}/{\beta}_H+{\alpha}/{\delta}$ (right) was increased for the right ${\alpha}$ dominance of yoga breathing group. On the contrary it was decreased for the left ${\alpha}$ dominance of yoga breathing group as well as the control regardless of the dominance. The result of this study implies that yoga breathing increases stress resistance and is effective in the management of physical stress. Emotionally relaxed people may have greater instantaneous stress reduction after yoga breathing. Moreover, yoga breathing could be also beneficial for depressed who may be more vulnerable to stress.

• Anxiety and mood
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• v.4 no.1
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• pp.3-10
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• 2008

The purpose of this review was to investigate the neurophysiological and neuroimaging characteristics of patients with depression and anxiety reported in previous studies. A literature search was conducted using Medline and psychiatric textbooks. "Electroencephalography (EEG)", "Event Related Potentials (ERP)", "functional neuroimaging", "heart rate variability (HRV)" and "depression or anxiety" were used as key words. A physiological finding indicated that there was a higher degree of relativity with regards to prefrontal dysfunction in patients with depression. Right prefrontal lobe hyperactivity and left prefrontal hypoactivity were consistently observed, and abnormalities were observed in other regions (ACC, hippocampus, amygdala, etc.). Therefore, dysfunctions in these areas are related to depressive symptoms. In patients with anxiety disorder, each emotional condition showed specific activation patterns in different brain regions, such as the prefrontal cortex, occipital lobe, temporal lobe, hippocampus, and limbic system, including the amygdala. However, in the majority of patients with anxiety disorder, the degree of activation was higher in the right hemisphere than in the left hemisphere. The current data supports that there is a difference in brain dysfunction characteristics between depression and anxiety and that the different activations of various brain regions would play a significant role in the pathophysiology of depression and anxiety disorder.

• Clinical and Experimental Pediatrics
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• v.64 no.4
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• pp.180-187
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• 2021

Background: Severe perinatal asphyxia results in multiple organ involvement, neonate hospitalization, and eventual death. Purpose: This study aimed to investigate the predictive factors of death in newborns with hypoxic-ischemic encephalopathy (HIE) receiving selective head cooling. Methods: This cross-sectional descriptive-retrospective study was conducted from 2013 to 2018 in Fatemieh Hospital of Hamadan and included 51 newborns who were admitted to the neonatal intensive care unit with a diagnosis of HIE. Selective head cooling for patients with moderate to severe HIE began within 6 hours of birth and continued for 72 hours. The required data for the predictive factors of death were extracted from the patients' medical files, recorded on a premade form, and analyzed using SPSS ver. 16. Results: Of the 51 neonates with moderate to severe HIE who were treated with selective head cooling, 16 (31%) died. There were significant relationships between death and the need for advanced neonatal resuscitation (P=0.002), need for mechanical ventilation (P=0.016), 1-minute Apgar score (P=0.040), and severely abnormal amplitude-integrated electroencephalography (a-EEG) (P=0.047). Multiple regression of variables or data showed that the need for advanced neonatal resuscitation was an independent predictive factor of death (P=0.0075) and severely abnormal a-EEG was an independent predictive factor of asphyxia severity (P=0.0001). Conclusion: All cases of neonatal death in our study were severe HIE (stage 3). Advanced neonatal resuscitation was an independent predictor of death, while a severely abnormal a-EEG was an independent predictor of asphyxia severity in infants with HIE.

• Journal of People, Plants, and Environment
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• v.24 no.1
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• pp.107-117
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• 2021

Background and objective: The purpose of this study is to investigate the effect of a forest healing program in terms of depression, neuropsychological and physiological benefits for the elderly. Methods: For this purpose, we developed a forest therapy program for the elderly who are vulnerable to dementia and conducted a total of 11 sessions of forest therapy activities in a forest once a week. We measured the changes in depression, resting-state Electroencephalography(EEG) and heart rate variability (HRV) before and after the program. There were 60 subjects aged over 65 yesrs old. 30 subjects participated in the forest therapy program, and the other were in the control group. The Geriatric Depression Scale was used to measure the level of depression, neuroNicle FX2 (Laxtha, Korea) was used to measure the resting-state EEG, and photoplethymogram (ubpulse T1, Laxtha, Korea) was used to measure the HRV. Results: The results showed that the depression index of the experimental group improved with statistical significance after the program (experiment group = 3.267 decrease of the mean). In the EEG measurement, the alpha-peak frequency at rest (experimental group = 0.227 Hz increase of the mean) was improved (mean increase = 0.23 in the experimental group, p < .05). The high frequency of HRV, which represents the parasympathetic nerve activity of the body's autonomous response, was also significantly improved (mean increase = 0.396 in the experimental group, p < .05). Conclusion: The results suggest that the forest therapy program can reduce the cognitive, psychological and physical risk factors of dementia for the elderly at risk of cognitive decline. Therefore, forest therapy activities may be suitable for the prevention of dementia in the elderly.