• Anxiety and mood
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• v.20 no.1
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• pp.8-16
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• 2024

Objective : The purpose of this study is to compare the signal obtained from the frontal 2-electrodes EEG with that obtained from the temporal, central, and parietal 2 electrodes. Methods : EEGs were recorded in a total of 67 patients with major depressive disorder (MDD), 104 patients with schizophrenia (SCZ), and 29 patients with Alzheimer's disease (AD). For each disease group, there were healthy controls (HC) that were paired accordingly (HC1=69, HC2=104, HC3=27). The following measurements were compared across electrodes: band power, alpha peak frequency (APF), APF power, alpha asymmetry (AA), and Kolmogorov complexity (KC). Results : Statistically significant differences were found in band power measured from frontal electrodes compared to electrodes placed in other locations. Specifically, the power of theta waves was measured higher in the temporal electorodes, alpha 1 and alpha 2 waves in the parietal, beta 1 and beta 2 in the central, and gamma waves in the temporal electrodes. Both SCZ and AD patients showed increased theta power in all electrodes. In SCZ patients, APF decreased in the central and temporal electrodes, but the APF power analysis showed no difference between the patients and controls. Additionally, AD patients exhibited increased AA in the central EEG, while SCZ patients showed decreased KC in the parietal and temporal electrodes. Conclusion : Depending on the electrode location, sensitive EEG frequencies differed. Compared with signals from other electrodes, frontal EEG in MDD patients revealed generally constant signal values, though the temporo-parieto-central electrodes appeared to be more reliable in SCZ and AD patients.

• Journal of Korea Multimedia Society
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• v.6 no.1
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• pp.167-175
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• 2003

In this paper, a new electrode configuration and EOG removal method are proposed in order to measure EEG effectively on the frontal lobe and remove EOG in the measured raw EEG. The method of measuring EEG is proposed using four electrodes and a ground electrode on the frontal lobe with a reference electrode at the left earlobe. And also, the separation method using ICA is proposed for EOG removal from the measured EEG, Through the experiments of measuring EEG it was demonstrated that a subject can attach the electrodes by himself easily to measure his own EEG without any assistant and the proposed methods were suitable for removing EOG signal from the measured EEG.

• Psychiatry investigation
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• v.15 no.11
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• pp.1087-1093
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• 2018

Objective Posttraumatic stress disorder (PTSD) is distinct from anxiety disorders in its etiology and clinical symptomatology, and was reclassified into trauma- and stressor-related disorders in DSM-5. This study aimed to find neurophysiological correlates differentiating PTSD from anxiety disorders using resting-state quantitative electroencephalography (qEEG). Methods Thirty-six patients with either PTSD or acute stress disorder and 79 patients with anxiety disorder were included in the analysis. qEEG data of absolute and relative powers and patients' medication status on the day of qEEG examination were obtained. Electrodes were grouped into frontal, central, and posterior regions to analyze for regional differences. General linear models were utilized to test for group differences in absolute and relative powers while controlling for medications. Results PTSD patients differed from those with anxiety disorders in overall absolute powers [F(5,327)=2.601, p=0.025]. Specifically, overall absolute delta powers [F(1,331)=4.363, p=0.037], and overall relative gamma powers [F(1,331)=3.965, p=0.047] were increased in PTSD group compared to anxiety disorder group. Post hoc analysis regarding brain regions showed that the increase in absolute delta powers were localized to the posterior region [F(1,107)=4.001, p=0.048]. Additionally, frontal absolute gamma powers [F(1,107)=4.138, p=0.044] were increased in PTSD group compared to anxiety disorder group. Conclusion Our study suggests increased overall absolute delta powers and relative gamma powers as potential markers that could differentiate PTSD from anxiety disorders. Moreover, increased frontal absolute gamma and posterior delta powers might pose as novel markers of PTSD, which may reflect its distinct symptomatology.

• The Korean Journal of Physiology
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• v.2 no.1
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• pp.53-58
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• 1968

In order to study the electrocardiogram of small animals authors deviced a fixing apparatus in the ventral resting position of rabbit and an attaching electrodes. Normal electrocardiograms of 8 adult rabbits were studied with author's improved fixing apparatus and electrodes. Leads taken were the standard limb lead, augmented unipolar leads and the unipolar precordial leads. The total numbers of various leads were eleven altogether. Results obtained in this study may be summarized as follows: 1. The details of the methods used to record and measure the six standard frontal plane leads and the five precordial leads of the rabbit electrocardiogram in the ventral resting position were described. The fixing apparatus of rabbits in ventral position are shown in Figure 1 and the attaching electrodes are shown in Figure 2. 2. The electrocardiographic changes in ventral position were more stable than in dorsal position in each lead. 3. The analysis of the amplitude, duration and other values of various waves are shown in Table 1 and Figure 3. 4. The electrocardiogram of rabbits showed decreased heart rate in ventral position than dorsal one. 5. The mean electrical axis of QRS complex in ventral position were +44.12 degrees and in dorsal position were +25.5 degrees.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.3
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• pp.6-12
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• 1983

The visual evoked potentials were measured using 19 electrodes attached to the scalp in 5 normal and 4 abnormal subjects during visual stimulation and these data were sampled for computer processing with 500 Hz sampling frequency. The center of potential distributions and its time-dependent locus were estimated from these potential distributions using weighting matrix which was determined by the electrodes' position coordinates. In normal subjects these estimated electrical signals were shown to propagate from the frontal lobe to the occipital lobe of the cortex following the known visual pathway. In abnormal subjects, there were significant differences in these estimated propagation pathway. The relationships among this model, the point source model and the dipole source model were analyzed.

• Biomolecules & Therapeutics
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• v.7 no.3
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• pp.242-248
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• 1999

Diazepam, a benzodiazepine (BDZ) agonist, produces sedation and flumazenil, a BDZ antagonist, blocks these actions. The aim of this study was to examine the effects of BDZs on cortical electroencephalogram (EEG) in rats. The recording electrodes were implanted over the frontal and parietal cortices bilaterally, and the reference and ground electrodes over cerebellum under ketamine anesthesia. To assess the effects of diazepam and flumazenil, rats were injected with diazepam (1 mgHg, i.p.) and/or flumazenil ( 1 mg/kg, i.p.), and the EEG was recorded before and after drugs. Normal awake had theta peak in the spectrum and low amplitude waves, while normal sleep showed large amplitude of slow waves. The powers of delta, theta and alpha bands were increased during sleep compared with during awake. Diazepam reduced the mobility of the rat and induced sleep with intermittent fast spindles and large amplitude of slow activity, and it produced broad peak over betaL band and increased the power of gamma band, which were different from EEG patterns in normal sleep. Saline injection awakened rats and abolished fast spindles for a short period about 2-5 min from EEG pattern during diazepam-induced sleep. Flumazenil blocked both diazepam-induced sleep and decreased the slow activities of delta, theta, alpha and betaL, but not of gamma activity for about 10 min or more. This study may indicate that decrease in power of betaL and betaH bands can be used as the measure of central action of benzodiazepines, and that the EEG parameters of benzodiazepines have to be measured without control over the behavioral state by experimenter.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.430-440
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• 2021

The purpose of this study was to analyze the degree of depression, cognitive function, communication ability, and the quantitative electroencephalogram (EEG) in elderly individuals with hearing loss and to investigate their inter-relationship. Hearing-impaired elderly participants, aged 60 years or older (37 men and 26 women) who visited the S Hearing Rehabilitation Center in Y City from June 20, 2020, to September 3, 2020, participated voluntarily after a recruitment announcement.The participants' overall characteristics, depression, and cognitive functions were evaluated with a structured questionnaire. The Word Recognition Score (WRS) was evaluated with an audiometer using the Korean Standard Monosyllabic Word Lists for Adults (KS-MWL-A). The quantitative EEG was measured with dry electrodes using a 2-channel EEG on the frontal lobes Fp1 and Fp2. The results are summarized as follows: Communication ability showed a positive correlation with the left-right symmetry of the frontal lobes (**p<.01) and a negative correlation with right-brain mental distraction and stress (*p<.05). In the difference WRS test for each group, the left-right symmetry of the frontal lobes (**p<.01) showed the greatest correlation with communication ability. Our results suggest that the left-right symmetry of the frontal lobes can be a biomarker indicative of the communication ability of older people with hearing impairments.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.12 no.1
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• pp.25-50
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• 2001

Using Fourier transformation and wavelet analysis, we compared the auditory event-related potentials of the patients with attention deficit-hyperactivity disorders(abbr. ADHD, 13 boys) and normal control children(8 boys). Amplitudes of the event-related potentials which were calculated via Fourier transformation were compared between the groups and between conditions(non-target versus target) in each group. To the non-target stimuli, the patients with ADHD showed significantly greater amplitudes across almost all of the electrode sites and frequencies. To the target stimuli, the incidents which ADHD patients showed much higher amplitudes than normal controls significantly decreased, while those of the reverse results increased significantly. These results were consistent with the comparison results about negative difference wave(abbr. Nd wave) using Fourier transformation. In summary, it was proved that non-target stimulus which should be ignored elicited more robust electrical response from the patients with ADHD than normal children, but the target stimulus which reguired active processing did much less electrical activity in the patients. For the patients, they showed much inhibited electrical response to the target stimuli in some electrodes and frequency ranges. Normal children were more strongly stimulated by the target stimuli in almost all electrodes and frequency ranges than the patients, but less in prefrontal leads and frontal leads. Wavelet analysis results proved that early responses(0-300msec) to the nontarget stimuli of the patients were significantly greater than the normal controls in prefrontal, anterior frontal, some parts of temporal, and occipital lobes and that late response(300-370msec) were significantly lesser than normal children in parietal and central electrodes. Target stimuli elicited significantly higher electrical activity in both group than non-target stimuli did. Prefrontal and frontal lobes showed stronger responses in the patients than normal children irrespective of stimulus condition, but parietal and temporal lobes did higher activities in normal children than the patients only to the target stimuli. In conclusion, the patients with ADHD showed much greater responses to the stimuli which should be ignored, but failed to activated the necessary processes to the target stimuli. Also, we found that the frequency-dimension analysis and wavelet analysis were useful for the signal processing such as event related potentials.

• Journal of Korean Neurosurgical Society
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• v.30 no.11
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• pp.1300-1307
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• 2001

Purposes : This study reports the possible causes of seizure recurrence in patients underwent previous epilepsy surgery, and surgical strategy for resection of the additional epileptogenic zone locating at the distant area to the site of first resection. Methods : A total of 10 patients with previous surgery due to intractable epilepsy were studied. Five of these underwent standard temporal lobectomy, four extratemporal resection, and one corticoamygdalectomy. Seizure outcome of these were class III-IV. Evaluation methods for reoperation included MRI, 3D-surface rendering of MRI, PET, prologned video-EEG recording with surface electrodes and subdural grid electrodes. Additional resection was done in the frontal lobe in two, in the temporal lobe in three, in the parietal lobe in two, and in the supplementary sensori-motor area in two. Tumor in the superior frontal gyrus in the left hemisphere was removed in one patient. Extent of resection was decided based on the results of ictal subdural grid EEGs and MRI findings. Awake anesthesia and electrocortical stimulation were performed in the two patients for defining the eloquent area. Results : Histopathologic findings revealed extratemporal cortical dysplasia in six, hippocampal sclerosis and cortical dysplasia of the temporal neocortex in one, neuronal gliosis in two, and meningioma in one. Previous pathology of the five patients with cortical dysplasia in the second operation was hippocampal sclerosis plus cortical dysplasia of the temporal neocortex. After reoperation, seizure outcomes were class I in six, class II in three, class III in one at the mean follow-up period of 17.5 months. Characteristically, patients in class II-III after reoperation showed histopathologic findings of hippocampal sclerosis plus temporal neocortical cortical dysplasia plus extratemporal cortical dysplasia. Conclusions : Seizure recurrence after epilepsy surgery was related with the presence of an additional epileptogenic zone distant to the site of first operation, and the majority of the histopathology of the surgical specimens was cortical dysplasia. In particular, hippocampal sclerosis plus temporal neocortical cortical dysplasia was highly related with seizure recurrence in patients with previous operation. In these patients, multimodal evaluation methods were necessary in defining the additional epileptogenic zone.

• Journal of Life Science
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• v.22 no.2
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• pp.192-199
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• 2012

This study investigated the effects of Lavandula angustifolia (L. angustifolia) aroma on the brain electrical activity evaluated by electroencephalogram (EEG) in female adults with sleep disorders. The subjects were 28 healthy female adults and their sleep disorders were classified by the Pittsburgh Sleep Quality Index. EEG electrodes were attached at the frontal (F3, F4), temporal (T3, T4), occipital (O1, O2), parietal (P3, P4), reference, and ground regions according to the International 10-20 system. Subjects were exposed to the L. angustifolia aroma for 3 min. Results showed that L. angustifolia aroma decreased the occipital and parietal alpha powers, and increased the frontal theta power and occipital beta power in subjects with good sleep quality. On the other hand, L. angustifolia aroma increased the theta power in the all cranial regions after aroma treatment in subjects with poor sleep quality. In conclusion, L. angustifolia aroma diminishes a state of wakefulness in the brain and helps individuals to fall asleep. Therefore, L. angustifolia aroma may have beneficial effect for female adults with sleep disorders.