Yeon Hak Chung

Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is a distinct CNS demyelinating disorder that differs from multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD). However, diagnosing MOGAD remains challenging due to the need to clinically exclude similar conditions and the variability in assay results. Wh...

Background and Purpose Treatments for neuromyelitis optica spectrum disorder (NMOSD) such as eculizumab, ravulizumab, satralizumab, and inebilizumab have significantly advanced relapse prevention, but they remain expensive. Rituximab is an off-label yet popular alternative that offers a cost-effective solution, but its real-world efficacy needs bet...

Importance A proportion of people with myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) have a relapsing disease course and persistent anti–myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG) seropositivity. Few studies have investigated whether treatment of the first MOGAD attack is associated with the long-term d...

Background and purpose: Fatigue is common in demyelinating disorders of the central nervous system (CNS), including multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). We aimed to validate the usefulness of the Functional Assessment of Chronic Illness...

Introduction: Although the relationship between migraine and multiple sclerosis (MS) has been reported, the risk of migraine in MS and neuromyelitis optica spectrum disorder (NMOSD) is unclear. Therefore, this study investigated the risk of migraine in the Korean MS and NMOSD populations. Methods: This study analyzed claims data from 1492 patien...

Mutations in the SACS gene are associated with autosomal recessive spastic ataxia of Charlevoix-Saguenay disease (ARSACS) or complex clinical phenotypes of Charcot-Marie-Tooth disease (CMT). This study aimed to identify SACS mutations in a Korean CMT cohort with cerebellar ataxia and spasticity by whole exome sequencing (WES). As a result, eight pa...

Background The risk–benefit relationship of immunosuppressive therapies (ISTs) for elderly patients with neuromyelitis optica spectrum disorder (NMOSD) is not well established. This study aimed to investigate the safety and efficacy of IST in elderly patients with NMOSD. Methods This retrospective study analysed IST efficacy and safety in 101 pati...

Mutations in the SACS gene are associated with autosomal recessive spastic ataxia of Charlevoix-Saguenay disease (ARSACS) or complex clinical phenotypes of Charcot-Marie-Tooth disease (CMT). This study aimed to identify SACS mutations in a Korean CMT cohort with cerebellar ataxia and spasticity. As a result, eight pathogenic SACS mutations in four...

Background: During the coronavirus disease 2019 (COVID-19) pandemic, patients with myasthenia gravis (MG) were more susceptible to poor outcomes owing to respiratory muscle weakness and immunotherapy. Several studies conducted in the early stages of the COVID-19 pandemic reported higher mortality in patients with MG compared to the general populat...

Background We investigated the risks of depression/anxiety in patients with multiple sclerosis (pwMS) or patients with neuromyelitis optica spectrum disorder (pwNMOSD). Objectives MS/NMOSD cohorts were collected from Korean National Health Insurance Service, using the International Classification of Diseases-10th and information on Rare Intractabl...

This study evaluates the antibody responses to SARS-CoV-2 vaccines in patients with neuroimmunological disorders (pwNID) who are receiving immunomodulating treatments, compared to healthy individuals. It included 25 pwNID with conditions such as optic neuritis, neuromyelitis optica spectrum disorder, multiple sclerosis, myasthenia gravis, and polym...

Background. Acute sensorineural hearing loss (SNHL) is a rare development in the central nervous system (CNS) demyelinating diseases such as aquaporin-4-IgG-positive neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). Methods. We retrospectively reviewed consecutive patients wi...

Background and purpose: Anti-neurofascin-155 (NF155) antibody is one of the autoantibodies associated with autoimmune nodopathy. We aimed to determine the clinical features of South Korean patients with anti-NF155-antibody-positive autoimmune nodopathy. Methods: The sera of 68 patients who fulfilled the diagnostic criteria for chronic inflammato...

Background: Serum levels of neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) reflect the disease activity and disability in central nervous system (CNS) demyelinating diseases. However, the clinical significance of NfL and GFAP in idiopathic transverse myelitis (iTM), an inflammatory spinal cord disease with unknown under...

Multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) are autoimmune inflammatory disorders of the central nervous system (CNS) with similar characteristics. The differential diagnosis between MS and NMOSD is critical for initiating early effective therapy. In this study, we developed a deep learning model to differentiate betw...

Objective Lateral temporal lobe epilepsy (LTLE) has been diagnosed in only a small number of patients; therefore, its surgical outcome is not as well-known as that of mesial temporal lobe epilepsy. We aimed to evaluate the long-term (5 years) and short-term (2 years) surgical outcomes and identify possible prognostic factors in patients with LTLE....

Background The detection of myelin oligodendrocyte glycoprotein autoantibodies (MOG-Ab) is essential for the diagnosis of MOG-Ab-associated disease (MOGAD). The clinical implications of different epitopes recognized by MOG-Ab are largely unknown. In this study, we established an in-house cell-based immunoassay for detecting MOG-Ab epitopes and exam...

Background: Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is a CNS autoimmune disease affecting the brain, spinal cord, and optic nerve. The neutrophil-to-lymphocyte ratio (NLR) is related to autoimmune disease activity. However, the clinical implication of index ratios such as the NLR is unclear in patients with MOGAD....

Background and purpose: Fingolimod (FTY) inhibits lymphocyte egress from lymphoid organs to cause lymphopenia, but the clinical implications of FTY-induced lymphopenia are not fully understood. We aimed to determine the frequency and severity of lymphopenia during FTY treatment among Korean patients with multiple sclerosis (MS), and its associatio...

Objectives Many patients with obstructive sleep apnea syndrome (OSAS) have nocturia. However, the predictive index of nocturia in patients with OSAS is currently not well known. We aimed to investigate the prevalence of nocturia in patients with OSAS and determine the factors that could predict nocturia in these patients. Methods In this retrospec...

Background : To determine the validity and reliability of the Korean version of the Modified Fatigue Impact Scale (MFIS-K) questionnaire for patients with multiple sclerosis (MS). Methods : We prospectively enrolled 52 patients with MS and 102 healthy controls. Subjects were asked to complete the Korean version of Fatigue Severity Scale (FSS) and...

Multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) are two representative chronic inflammatory demyelinating disorders of the central nervous system. We aimed to determine and compare the alterations of white matter (WM) connectivity between MS, NMOSD, and healthy controls (HC). This study included 68 patients with relapsing...

Neurocysticercosis (NCC) is the most common central nervous system parasite infection, frequently produces seizure, headache, or hydrocephalus as clinical manifestations. Cerebral vasculitis is an infrequent complication of the clinical phenotype of NCC. Moreover, NCC involving basal cerebral arteries, including distal internal carotid artery or mi...