Publications by authors named "Woon Yoon"

Alzheimer's disease (AD) is a progressive neurodegenerative disease associated with a complex genetic etiology. Besides the apolipoprotein E ε4 (APOE ε4) allele, a few dozen other genetic loci associated with AD have been identified through genome-wide association studies (GWAS) conducted mainly in individuals of European ancestry. Recently, several GWAS performed in other ethnic groups have shown the importance of replicating studies that identify previously established risk loci and searching for novel risk loci.

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While white matter impairments play an integral part in the pathophysiology of schizophrenia and bipolar disorder, the literature on white matter abnormality differences between the two disorders is insufficient. The University of California Los Angeles Consortium for Neuropsychiatric Phenomic LA5c public dataset, including 47 patients with schizophrenia, 47 with bipolar disorder, and 115 healthy controls, was obtained via OpenNeuro. Whole-brain tractography was performed using Unscented Kalman filter-based two-tensor tractography and White Matter Query Language.

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We investigated the association between herpes zoster (HZ) and dementia, and the effects of antiviral therapy on the risk of dementia. We used the National Health Insurance Service-National Sample Cohort in South Korea to identify individuals that were followed from January 1, 2002, to December 31, 2013. Occurrences of HZ and dementia were identified using the relevant diagnostic codes.

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Purpose: Despite a large number of resting-state functional MRI (rsfMRI) studies in schizophrenia, current evidence on the abnormalities of functional connectivity (FC) of resting-state networks shows high variability, and the findings on recent-onset schizophrenia are insufficient compared to those on chronic schizophrenia.

Patients And Methods: We performed a rsfMRI in 46 patients with recent-onset schizophrenia and 22 healthy controls. Group independent component brainmap and dual regression were performed for voxel-wise comparisons between the groups.

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Article Synopsis
  • The study aimed to quantify the number of brain regions with abnormal diffusion measures in patients with schizophrenia using diffusion tensor imaging.
  • Data from 57 schizophrenia patients and 71 healthy participants were analyzed, focusing on 161 brain regions and using Z-scores to classify each region as normal or abnormal.
  • Results indicated that patients showed significantly more abnormal regions with altered diffusivity, suggesting that schizophrenia involves multiple structural brain changes rather than a single region's pathology.
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Objective: Working memory impairments serve as prognostic factors for patients with schizophrenia. Working memory deficits are mainly associated with gray matter (GM) thickness and volume. We investigated the association between GM diffusivity and working memory in controls and individuals with schizophrenia.

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Article Synopsis
  • This study investigated antidepressant prescription patterns for bipolar disorder in Korea using data from 2010, 2011, and 2013.
  • Over the three years, the annual prescription rate of antidepressants increased from 27.3% to 33.6%, with a notable rise in the combination of antidepressants and antipsychotics.
  • Escitalopram was the most commonly prescribed antidepressant, and the need for more empirical evidence to guide treatment in bipolar disorder was emphasized.
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Several studies have produced extensive evidence on white matter abnormalities in schizophrenia (SZ). However, optimum consistency and reproducibility have not been achieved, and reported low white matter tract integrity in patients with SZ varies between studies. A whole-brain imaging study with a large sample size is needed.

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Schizophrenia is a heterogenous neuropsychiatric disorder with varying degrees of altered connectivity in a wide range of brain areas. Network analysis using graph theory allows researchers to integrate and quantify relationships between widespread changes in a network system. This study examined the organization of brain structural networks by applying diffusion MRI, probabilistic tractography, and network analysis to 48 schizophrenia patients and 24 healthy controls.

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We report a case of spontaneous bilateral intracranial vertebral artery dissecting aneurysms with subarachnoid hemorrhage. One dissecting lesion was treated with a coronary balloon-mounted stent (BMS) technique; however, due to differences in access route tortuosity, the other lesion was treated with a self-expandable stent (SES) technique. After 2 months, the angiographic outcome showed complete healing of the dissected segment on the side that was treated with BMS; in contrast, the dissection lesion appeared to be re-growing on the side that was treated with SES.

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The simultaneous recording of electroencephalogram (EEG) and functional magnetic resonance image (fMRI) is a promising tool that is capable of providing high spatiotemporal brain mapping. One of the difficulties to obtain high-quality simultaneous EEG/fMRI data comes from the heartbeat artifact induced in the EEG recorded within fMRI scanner. The purpose of this study was to develop a novel algorithm for removing heartbeat artifact, thus overcoming problems associated with previous methods.

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