• Korean Journal of Biological Psychiatry
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• v.7 no.2
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• pp.180-185
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• 2000

Objective : The present study was designed to compare Global Field Power Measurement and conventional method in P300 determination. Method : The subjects were composed of patients(N=20) with schizophrenia by DSM-IV and normal controls(N=20). The auditory event related potential P300 was measured by "oddball paradigm". P300 components were determined by Global Field Power Measurement and conventional method at 5 electrodes(Fz, Cz, Pz, $T_3$, $T_4$). Results : P300 amplitudes of patients were smaller than those of controls across all electrodes and in both methods, but there was no differential power in P300 determination between two methods. Asymmetry of auditory event-related potential P300 was not shown between patients with schizophrenia and normal controls. Conclusion : It is implicated that it depends on clinical situations and research purposes what method of P300 determination will be more appropriate for patients with schizophernia.

• Journal of Biomedical Engineering Research
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• v.30 no.4
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• pp.306-310
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• 2009

The purpose of this study is to observe the change in gamma-band cortical activities (GBAs) due to task difficulty. Event-related potential and gamma-band activity were investigated using electroencephalograms recorded during auditory oddball tasks with two difficulty levels. For more difficult task, the amplitude of P300 decreased and the peak latency of P300 was delayed significantly compared to easier task. The induced GBA decreased considerably during the P300 latency period and the peak latency of the induced GBA was delayed for more difficult task. The results imply that the difficulty-related change in cortical information processing may be implemented as a change in the strength of local neuronal association.

• Journal of information and communication convergence engineering
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• v.8 no.2
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• pp.234-237
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• 2010

P300 component of the event-related potential(ERP) has been studied for theoretical, empirical, and clinical applications. Nowadays the 1-, 2-, and 3-stimulus oddball paradigms are used for eliciting P300 component of EEG in the auditory stimulus experiments. In this paper, we used a method to add one more stimulus to the 3-stimulus auditory paradigm. The adding stimulus has not the same volume but the same tone of the target stimulus. The 4-stimulus oddball paradigm to use two targets is used to elicit the P300 event-related potentials. In 4-stimulus oddball paradigm, an infrequent non-target (p=0.10) is presented in addition to two infrequent targets (p=0.10) and a frequent standard (p=0.70). Two target stimuli elicited a P300 component with a parietal maximum distribution. The amplitude of the P300 in target 2 was larger than that in target 1 and the latency of the P300 in target 2 was longer than that in target 1. The P300 component due to target 2 stimuli was larger than that due to target 1 stimuli. The experimental results approve that the 4-stimulus oddball paradigm can elicit P300 component clearly. The results are compared with the results of the traditional oddball paradigm.

• Sleep Medicine and Psychophysiology
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• v.10 no.2
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• pp.108-112
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• 2003

Objectives: The purpose of this study is to investigate the psychophysiological effects of total sleep deprivation by using auditory event-related potentials. Methods: Twenty four healthy college students (18 men, 6 women) participated in this study. The subjects remained awake for 37 hours under continuous surveillance. In the morning and the evening of two consecutive study days, auditory event-related potentials were checked. Results: The latencies of P300 and N200 were significantly prolonged (p<0.001) and their amplitudes decreased (p<0.05) as a consequence of sleep deprivation. The amplitude of P200 was significantly increased during sleep deprivation (p<0.05). However, there was no significant change in the latency and amplitude of N100. Conclusion: Among the components of auditory event-related potentials, P300 and N200 are good indicators of sleep-deprived status. Further investigation is necessary to elucidate the neurophysiological mechanisms of these findings.

• Journal of Biomedical Engineering Research
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• v.41 no.1
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• pp.22-27
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• 2020

Auditory stimuli are commonly used in various electroencephalogram experiments, also in EEG-based brain-computer interface systems. However, using conventional earphones that blocks the ear canal attenuates or even blocks external environmental sound which might cause loss of crucial information from surroundings. Instead, bone-conductive earphones are able to deliver sound through vibration without blocking the ear canal. To investigate the feasibility of the bone-conductive earphones for auditory-stimuli based experiments, we compared N100 event-related potential features as well the event-related spectral perturbation and inter-trial coherence of auditory steady-state response between conventional and bone-conductive earphones. The results showed no significant differences between bone conduction and conventional earphones regardless of distinct sound pressures. This result shows that bone conductive earphones can be used for auditory experiments when the environmental sound is crucial to the user.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.22 no.4
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• pp.211-218
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• 2011

Objectives : Intellectual impairment in children with attention-deficit hyperactivity disorder (ADHD) is often associated with relatively severe cognitive dysfunction. This study was designed to investigate cognitive function using auditory and visual event-related potential P300 in children with ADHD with relatively higher and lower IQ. Methods : A total of 20 children aged 6-12 years with DSM-IV-TR diagnosis of ADHD-combined type were recruited. For 10 children with lower IQ (${\leq}$100) and 10 children with higher IQ (>100), auditory and visual P300 using oddball paradigm (target 0.2, standard 0.8, in probability) were employed. Results : No significant differences were found in P300 amplitude and latency between ADHD children with higher and lower IQ in both modalities. However, auditory P300 amplitude in the right parietal area (P8 electrode) was negatively correlated with verbal IQ in ADHD subjects (R=-.50, p<.05). Visual P300 amplitude in the left parietal area (P3 electrode) was positively correlated with performance IQ in ADHD subjects (R=.57, p<.01). Conclusion : This study suggests intellectual impairment, as evidenced by lower IQ, could not be associated with cognitive dysfunction reflected in event-related potential P300 in ADHD children. However, cognitive function reflected in intellectual subcomponents and P300 might be processed in a stimulus modality-specific and asymmetric pattern.

• Korean Journal of Biological Psychiatry
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• v.13 no.3
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• pp.137-143
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• 2006

One of the most widely recognized neurophysiologic endophenotypes for schizophrenia is deficient gating or inhibition of the P50 component of the auditory event-related potential(ERP). A deficit in P50 sensory gating refers to a dysfunction in the mechanism responsible for modulating the brain's sensitivity of filtering out irrelevant or background stimuli, perhaps as a result of dysfunction in inhibitory neural circuits. In this paper, we review the neuronal and genetic aspects as well as medication effects on P50 in schizophrenia.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2002.11a
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• pp.148-152
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• 2002

This study is to develop the Alzheimers disease (AD) detection and analysis system using event-related potential (ERP) of AD patients. We recorded ERP in an auditory oddball paradigm in mild AD (n=25), severe AD (n=12), age-matched normal aged controls (n=17), and young controls (n=7). The amplitude and latency of target P300 components were compared among 4 groups. The relationship between P300 measures and neuro psychological test (K-DRS) scores were evaluated by correlations. The latency of P300 was prolonged in AD and the effects were correlated with the severity of dementia. The P300 amplitude was not affected significantly in AD. Theres no difference between normal aged group and young group. These results suggest that the P300 component is specifically affected by Alzheimer type dementia.

• Korean Journal of Biological Psychiatry
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• v.11 no.1
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• pp.40-48
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• 2004

Objective:Event-related potentials(ERPs) are electrical changes recorded at the surface of the scalp in response to stimulus presentation, and their latency and amplitude change according to cognitive processes. Through past studies of the auditory ERP in schizophrenia, the P300 has been reported to be statistically smaller and delayed in schizophrenia than comparison groups. However, studies of the visual ERP have not been systematically examined. The present study was designed to investigate the visual P300 in patients with schizophrenia and normal controls and to compare the pattern of P300 between them. Methods:The subjects were composed of patients(N=22) with schizophrenia by DSM-IV and normal controls(N=22). The visual ERPs were measured by the visual continuous performance test. P300 amplitude and latency measured on 5 scalp electrodes(Fz, Cz, Pz, $T_7$, $T_8$) were compared between patients and controls. Results:The P300 latencies measured on Fz, Cz, Pz, and $T_7$ electrodes were significantly longer in patients than controls(p<0.05). The P300 amplitudes in patients were smaller than controls. However, the difference between them was not statistically significant. Conclusion:Analysis of the visual ERPs showed that the P300 latency is significantly delayed and the P300 amplitude is slightly smaller in patients than controls. These results are similar to established studies of the auditory P300 in schizophrenia.

• Sleep Medicine and Psychophysiology
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• v.1 no.1
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• pp.87-98
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• 1994

Objectives: To examine a defect in inhibitory gating of auditory evoked response in schizophrenics, to compare P3 latency and amplitude in negative and positive schizophrenics, and to assess the association of P3 with family history of the psychiatric disorders, electroconvulsive therapy, and clinical features. Methods: 54 schizophrenics(male 31, female 23) and 75 controls(male 33, female 42) were tested with event-related potential paradigm designed to elicit P3 response and Frankfurter Beschwerde Fragebogen. Results: In schizophrenics, the latency of P3 was significantly more delayed and the amplitude of P3 was significantly more reduced than in the controls. Significant differences in P3 latency and amplitude between negative and positive schizophrenics were not found. And significant difference in the P3 latency and amplitude between schizophrenics with family histories of psychiatric disorder and those without family histories of psychiatric disorder was not found also. The P3 latency and amplitude was not significantly related with electroconvulsive therapy and other clinical features such as age, duration of illness, onset of inllness, number of admission, and doses of antipsychotics etc. Conclusion: These results suggested that schizophrenics had a dysfunction in the process of selective attention and that P3 was not significantly related with family history of the psychiatric disorders, positive and negative symptoms, electro1convulsive therapy, and clinical features in schizophrenics.