Test–Retest Reliability of Attention Network Test Scores in Schizophrenia / 정신신체의학

OBJECTIVES: Although the Attention Network Test(ANT) has been widely used to assess selective attention including alerting, orienting, and conflict processing, data on its test-retest reliability are lacking for clinical population. The objective of the current study was to investigate test-retest reliability of the ANT in healthy controls and patients with schizophrenia. METHODS: Fourteen patients with schizophrenia and 23 healthy controls participated in the study. They are tested with ANT twice with 1 week interval. Test–retest reliability was analyzed with Pearson and Intra-class correlations. RESULTS: Patients with schizophrenia showed high test–retest correlations for mean reaction time, orienting effect, and conflict effect. Also, they showed moderate to high test-retest correlations for mean accuracy and moderate test-retest correlations for alerting effect and conflict error rate. On the other hand, healthy controls revealed high test–retest correlations for mean reaction time and moderate to high test-retest correlations for conflict error rate. In addition, they revealed moderate test-retest correlations for alert effect, orienting effect, and conflict effect. CONCLUSIONS: The mean reaction time, alerting effect, orienting effect, conflict effect, and conflict error rate of ANT showed acceptable test–retest reliabilities in healthy controls as well as patient with schizophrenia. Therefore, the analyses of these reliable measures of ANT are recommended for case-control studies in patients with schizophrenia.

The Quality Control Program for Industrial Hygiene Laboratories in Korea

In 1992, the quality control program was introduced in Republic of Korea to improve the reliability of the work environment monitoring, which was introduced in the 1980s. The commission entrusted by the Ministry of Employment and Labor, the Occupational Safety and Health Research Institute has conducted the program for industrial hygiene laboratories including designated monitoring institutions and spontaneously participating agencies. The number of institutions that participated in the program has increased from 30 to 161. The initial conformance ratio in the participants was 43% (organic solvents) and 52% (metals). Thereafter, the conformance ratio increased rapidly and it has remained in a stable state at more than 89% since 1996. As subject materials, 13 kinds of organic solvents and 7 kinds of metals were used. To improve the capability of measurement and analysis of private institutions, educational courses were conducted annually. An assessment at the actual sites of participants was additionally introduced into the program in 2013. Thus, the program turned into a system that administrates the overall process of participants. For the future, the scope of target materials will be extended through additional items. Thus, the reliability of the results of the work environment monitoring is expected to increase accordingly.

Repolarization Heterogeneity of Magnetocardiography Predicts Long-Term Prognosis in Patients with Acute Myocardial Infarction

PURPOSE: Magnetocardiography (MCG) has been proposed as a noninvasive, diagnostic tool for risk-stratifying patients with acute myocardial infarction (AMI). This study evaluated whether MCG predicts long-term prognosis in AMI. MATERIALS AND METHODS: In 124 AMI patients (95 males, mean age 60±11 years), including 39 with ST-elevation myocardial infarction, a 64-channel MCG was performed within 2 days after AMI. During a mean follow-up period of 6.1 years, major adverse cardiac events (MACE) were evaluated. RESULTS: MACE occurred in 31 (25%) patients, including 20 revascularizations, 8 deaths, and 3 re-infarctions. Non-dipole patterns were observed at the end of the T wave in every patients. However, they were observed at T-peak in 77% (24/31) and 54% (50/93) of patients with and without MACE, respectively (p=0.03). Maximum current, field map angles, and distance dynamics were not different between groups. In the multivariate analysis, patients with non-dipole patterns at T-peak had increased age- and gender-adjusted hazard ratios for MACE (hazard ratio 2.89, 95% confidence interval 1.20–6.97, p=0.02) and lower cumulative MACE-free survival than those with dipole patterns (p=0.02). CONCLUSION: Non-dipole patterns at T-peak were more frequently observed in patients with MACE and were related to poor long-term prognosis. Thus, repolarization heterogeneity measured by MCG may be a useful predictor for AMI prognosis.

The Effect of Bilateral Eye Movements on Face Recognition in Patients with Schizophrenia / 정신신체의학

OBJECTIVES: The deficit of recognition memory has been found as one of the common neurocognitive impairments in patients with schizophrenia. In addition, they were reported to fail to enhance the memory about emotional stimuli. Previous studies have shown that bilateral eye movements enhance the memory retrieval. Therefore, this study was conducted in order to investigate the memory enhancement of bilaterally alternating eye movements in schizophrenic patients. METHODS: Twenty one patients with schizophrenia participated in this study. The participants learned faces (angry or neutral faces), and then performed a recognition memory task in relation to the faces after bilateral eye movements and central fixation. Recognition accuracy, response bias, and mean response time to hits were compared and analysed. Two-way repeated measure analysis of variance was performed for statistical analysis. RESULTS: There was a significant effect of bilateral eye movements condition in mean response time(F=5.812, p<0.05) and response bias(F=10.366, p<0.01). Statistically significant interaction effects were not observed between eye movement condition and face emotion type. CONCLUSIONS: Irrespective of the emotional difference of facial stimuli, recognition memory processing was more enhanced after bilateral eye movements in patients with schizophrenia. Further study will be needed to investigate the underlying neural mechanism of bilateral eye movements-induced memory enhancement in patients with schizophrenia.

EEG Source Imaging in Partial Epilepsy in Comparison with Presurgical Evaluation and Magnetoencephalography

BACKGROUND AND PURPOSE: The aim of this study was to determine the usefulness of three-dimensional (3D) scalp EEG source imaging (ESI) in partial epilepsy in comparison with the results of presurgical evaluation, magnetoencephalography (MEG), and electrocorticography (ECoG). METHODS: The epilepsy syndrome of 27 partial epilepsy patients was determined by presurgical evaluations. EEG recordings were made using 70 scalp electrodes, and the 3D coordinates of the electrodes were digitized. ESI images of individual and averaged spikes were analyzed by Curry software with a boundary element method. MEG and ECoG were performed in 23 and 9 patients, respectively. RESULTS: ESI and MEG source imaging (MSI) results were well concordant with the results of presurgical evaluations (in 96.3% and 100% cases for ESI and MSI, respectively) at the lobar level. However, there were no spikes in the MEG recordings of three patients. The ESI results were well concordant with MSI results in 90.0% of cases. Compared to ECoG, the ESI results tended to be localized deeper than the cortex, whereas the MSI results were generally localized on the cortical surface. ESI was well concordant with ECoG in 8 of 9 (88.9%) cases, and MSI was also well concordant with ECoG in 4 of 5 (80.0%) cases. The EEG single dipoles in one patient with mesial temporal lobe epilepsy were tightly clustered with the averaged dipole when a 3 Hz high-pass filter was used. CONCLUSIONS: The ESI results were well concordant with the results of the presurgical evaluation, MSI, and ECoG. The ESI analysis was found to be useful for localizing the seizure focus and is recommended for the presurgical evaluation of intractable epilepsy patients.

Online Learning for Classification of Alzheimer Disease based on Cortical Thickness and Hippocampal Shape Analysis / 대한의료정보학회지

OBJECTIVES: Mobile healthcare applications are becoming a growing trend. Also, the prevalence of dementia in modern society is showing a steady growing trend. Among degenerative brain diseases that cause dementia, Alzheimer disease (AD) is the most common. The purpose of this study was to identify AD patients using magnetic resonance imaging in the mobile environment. METHODS: We propose an incremental classification for mobile healthcare systems. Our classification method is based on incremental learning for AD diagnosis and AD prediction using the cortical thickness data and hippocampus shape. We constructed a classifier based on principal component analysis and linear discriminant analysis. We performed initial learning and mobile subject classification. Initial learning is the group learning part in our server. Our smartphone agent implements the mobile classification and shows various results. RESULTS: With use of cortical thickness data analysis alone, the discrimination accuracy was 87.33% (sensitivity 96.49% and specificity 64.33%). When cortical thickness data and hippocampal shape were analyzed together, the achieved accuracy was 87.52% (sensitivity 96.79% and specificity 63.24%). CONCLUSIONS: In this paper, we presented a classification method based on online learning for AD diagnosis by employing both cortical thickness data and hippocampal shape analysis data. Our method was implemented on smartphone devices and discriminated AD patients for normal group.

The Effect of Bilateral Eye Movements on Emotional Face Recognition Memory Task / 신경정신의학

OBJECTIVES: Previous studies have shown that bilateral eye movements enhance episodic memory retrieval. However, few studies on the effect of bilateral eye movements on emotional memory have been reported. Therefore, this study was conducted in order to investigate the differences in memory retrieval between neutral and angry stimuli after bilaterally alternating eye movements. METHODS: Twenty seven healthy right-handed subjects participated in this study. The participants learned faces (angry or neutral face), and then performed a recognition memory task in relation to the faces after bilateral eye movements and central fixation. Recognition accuracy, response bias, and mean response time to hits were compared and analyzed. Two-way repeated measure analysis of variance was performed for statistical analysis. RESULTS: There was a significant effect of bilateral eye movement conditions in recognition accuracy (F=13.833, p<0.01). Statistically significant interaction effects were observed between eye movement condition and face emotion type (F=6.253, p=0.02). CONCLUSION: In this study, recognition memory for angry faces was more enhanced than that for neutral faces after bilateral eye movements. This finding suggests that bilateral eye movements can improve recognition memory for emotional stimuli more than that for neutral stimuli.

The Effect of Bilateral Eye Movements on Emotional Face Recognition Memory Task / 신경정신의학

OBJECTIVES: Previous studies have shown that bilateral eye movements enhance episodic memory retrieval. However, few studies on the effect of bilateral eye movements on emotional memory have been reported. Therefore, this study was conducted in order to investigate the differences in memory retrieval between neutral and angry stimuli after bilaterally alternating eye movements. METHODS: Twenty seven healthy right-handed subjects participated in this study. The participants learned faces (angry or neutral face), and then performed a recognition memory task in relation to the faces after bilateral eye movements and central fixation. Recognition accuracy, response bias, and mean response time to hits were compared and analyzed. Two-way repeated measure analysis of variance was performed for statistical analysis. RESULTS: There was a significant effect of bilateral eye movement conditions in recognition accuracy (F=13.833, p<0.01). Statistically significant interaction effects were observed between eye movement condition and face emotion type (F=6.253, p=0.02). CONCLUSION: In this study, recognition memory for angry faces was more enhanced than that for neutral faces after bilateral eye movements. This finding suggests that bilateral eye movements can improve recognition memory for emotional stimuli more than that for neutral stimuli.

The Effect of Bilaterally Alternating Auditory Stimulations on the Episodic Memory Retrieval / 신경정신의학

OBJECTIVES: Previous research has shown that bilaterally alternating eye movements enhance episodic memory retrieval. This effect has been considered an important mechanism of the therapeutic effects of eye movement desensitization and reprocessing (EMDR) treatment. We conducted this study in order to test the hypothesis that bilaterally alternating auditory stimuli would also have similar effects on episodic memory retrieval. METHODS: Thirty eight right-handed subjects participated in this study. Subjects learned words, and then received bilaterally alternating auditory stimuli (as experimental stimuli) or unilateral auditory stimuli (as control stimuli). Subsequently, they performed recognition memory task. Recognition accuracy, response bias, and mean response to hits were used for evaluation of episodic memory retrieval. Repeated measures analysis of variance was performed for statistical analysis. RESULTS: There was no significant effect of experimental conditions in recognition accuracy, the response bias, and mean response time to hits. CONCLUSION: Unlike the previous positive results of bilaterally alternating eye movements, we did not observe an enhancing effect of bilaterally alternating auditory stimuli compared to unilateral auditory stimuli on episodic memory retrieval. This result suggests the possibility that the therapeutic mechanisms of EMDR might differ according to modalities of bilateral stimulation.