• Korean Journal of Biological Psychiatry
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• v.24 no.4
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• pp.188-195
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• 2017

Objectives Schizophrenia is characterized by disturbances in perception and cognition. Attenuated mismatch negativity (MMN) reflects central auditory dysfunction in schizophrenia. The aim of this study is to compare MMN changes before and after treatment in schizophrenia patients and to assess their association with treatment response. Methods Twenty-three schizophrenia patients underwent an oddball paradigm. MMN was calculated by the difference waveforms of the event-related potentials (ERPs) elicited by subtracting standard from deviant stimulus. The clinical symptoms were measured by the Positive and Negative Syndrome Scale (PANSS), the Psychotic Symptom Rating Scale (PSYRATS). Follow-up evaluation was conducted when the PANSS total score decreased by 30% or more (treatment response group) or before discharge (non-response group). Results The treatment response group showed significantly larger MMN amplitude improvement and latency reduction than the non-response group after treatment (Fz ; mean amplitude p = 0.035, FCz ; p = 0.041). The auditory hallucination group showed shorter latency than that of the group without hallucinations. Additionally, auditory hallucination was associated with prolonged MMN latency and shortened after treatment in the auditory hallucination response group (Fz ; p = 0.048). Conclusions These results suggest that the attenuated MMN amplitude reflects the progression of the disease. The increment of MMN amplitude and shortening of latency after treatment may reflect cognitive functional recovery of central auditory sensory processing.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.7 no.2
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• pp.179-189
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• 1996

Objective : This study was conducted to find out the electrophysiological abnormalities of the patients with attention-deficit/hyperactivity disorder(abbr. ADHD) through identifying the profiles of the event-related potentials. Methods : Through measuring event-related potentials of 20 patients with ADHD and 16 normal control children using Oddball paradigm, we evaluated the latencies and amplitudes of each wave form. Results : In the group older than 9 years old, the latencies that reflect selective attention and discriminative capacity of the patients with ADHD were significantly longer than those of normal controls, which suggests that patients with ADHD be more distractible to non-significant stimuli and that they be in lark of sustained attention and discriminative ability. Conclusions : We concluded that the patients with ADHD are more distractible to trivial stimuli than normal children but they lack discriminative, sustained ability of attention.

• 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.

• Anxiety and mood
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• v.17 no.2
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• pp.84-91
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• 2021

Objective : Mismatch negativity (MMN) is known to reflect several abnormalities of cognitive functioning. This study is aimed to investigate the differences in MMN among major depressive disorder (MDD) patients with or without suicidal ideation. Methods : Sixty-seven patients with MDD were recruited into this study. MMN was measured by a 64-channel electroencephalography (EEG) using oddball paradigm over the front-central area. Clinical characteristics were assessed using the Beck Anxiety Inventory (BAI), the Beck Depression Inventory-II (BDI-II), and the Beck Scale for Suicide ideation (SSI-BECK). Patients were divided into two groups, no suicidal ideation (N=12) and suicidal ideation (N=55), depending on the presence of suicide ideation in SSI-BECK questionnaires. Results : The MMN latencies were significantly longer in the MDD patients with suicidal ideation than in the MDD patents without suicidal ideation (p<0.05). The MMN amplitudes were not significantly different between the two groups. Conclusion : Suicidal ideation may be associated with longer MMN latencies, and it suggests that MMN may play a potential role in assessing the suicidal risk among MDD patients.

• Korean Journal of Cognitive Science
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• v.35 no.1
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• pp.49-95
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• 2024

Polygraph examination, statement validity analysis and P300-based concealed information test are major three examination tools, which are use to determine a person's truthfulness and credibility in criminal procedure. Although polygraph examination is most common in criminal procedure, but it has little admissibility of evidence due to the weakness of scientific basis. In 1990s to support the weakness of scientific basis about polygraph, Farwell and Donchin proposed the P300-based concealed information test technique. The P300-based concealed information test has two strong points. First, the P300-based concealed information test is easy to conduct with polygraph. Second, the P300-based concealed information test has plentiful scientific basis. Nevertheless, the utilization of P300-based concealed information test is infrequent, because of the quantity of probe stimulus. The probe stimulus contains closed information that is relevant to the crime or other investigated situation. In tradition P300-based concealed information test protocol, three or more probe stimuli are necessarily needed. But it is hard to acquire three or more probe stimuli, because most of the crime relevant information is opened in investigative situation. In addition, P300-based concealed information test uses oddball paradigm, and oddball paradigm makes imbalance between the number of probe and irrelevant stimulus. Thus, there is a possibility that the unbalanced number of probe and irrelevant stimulus caused systematic underestimation of P300 amplitude of irrelevant stimuli. To overcome the these two limitation of P300-based concealed information test, one-probe P300-based concealed information test protocol is explored with various machine learning algorithms. According to this study, parameters of the modified one-probe protocol are as follows. In the condition of female and male face stimuli, the duration of stimuli are encouraged 400ms, the repetition of stimuli are encouraged 60 times, the analysis method of P300 amplitude is encouraged peak to peak method, the cut-off of guilty condition is encouraged 90% and the cut-off of innocent condition is encouraged 30%. In the condition of two-syllable word stimulus, the duration of stimulus is encouraged 300ms, the repetition of stimulus is encouraged 60 times, the analysis method of P300 amplitude is encouraged peak to peak method, the cut-off of guilty condition is encouraged 90% and the cut-off of innocent condition is encouraged 30%. It was also conformed that the logistic regression (LR), linear discriminant analysis (LDA), K Neighbors (KNN) algorithms were probable methods for analysis of P300 amplitude. The one-probe P300-based concealed information test with machine learning protocol is helpful to increase utilization of P300-based concealed information test, and supports to determine a person's truthfulness and credibility with the polygraph examination in criminal procedure.

• 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.

• Annals of Clinical Neurophysiology
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• v.3 no.2
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• pp.136-142
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• 2001

Background : Nervous system dysfunction is a major complication of end stage renal disease. Although severe neurologic symptoms are partially or completely reversed by adequate hemodialysis, even optimally dialyzed patients will usually not return to normal neurocognitive function. To investigate the influence of chronic renal failure and hemodialysis on higher cognitive function electrophysiologically, we studied auditory P300 event-related potentials in 14 hemodialysis patients and 14 age- and sex-matched normal healthy controls. Methods : The subjects consisted of 14 patients(M: 6, F: 8) with chronic renal failure(CRF) for 1 to 10 years and 14 age- and sex-matched healthy controls(M: 5, F: 9). For the reliability of study, patients with diabetes mellitus, abnormal brain CT findings, or low mini-mental state score(below 20) were excluded. Event related potentials(ERPs) for hemodialysis patients were performed at pre- and post-hemodialysis. To obtain ERPs, subjects underwent 2-tone auditory discrimination test(oddball paradigm). Results : Although the age(control: $48.79{\pm}10.31years$, CRF: $51.21{\pm}7.61years$) and mini-mental state score(control: $27.00{\pm}1.71points$, predialysis CRF: $25.07{\pm}3.58points$) were not different in normal control and CRF groups significantly(P>0.05), P300 latencies at Cz(control: $288.11{\pm}17.36msec$, predialysis CRF: $332.35{\pm}42.34msec$) were significantly delayed(P<0.05)and the duration of Trail making test A was significantly prolonged(control: $64.2{\pm}24.2sec$, CRF: $118.9{\pm}101sec$) in CRF group. P300 latencies between pre- and post-hemodialysis CRF patients(predialysis CRF: $332.35{\pm}42.34msec$, postdialysis CRF: $325.82{\pm}38.69msec$) were not significantly different. The P300 latency was not related with the duration of CRF(Spearman's correlation test, r=0.25, P>0.05) and the frequency of hemodialysis(Spearman's correlation test, r=0.28, P>0.05). Conclusions : From these results, we suggest that P300 latency is valuable in evaluating cognitive brain dysfunction in patients with CRF and hemodialysis does not have a significant effect on cognitive brain dysfunction in patients with CRF.