Advances in network science and computer engineering have enabled brain connectivity analysis using clinical big data such as brain magnetic resonance imaging (MRI), electroencephalography (EEG), or magnetoencephalography (MEG). Resting-state functional connectivity analysis aims to reveal the characteristics of functional brain network in various diseases and normal brain maturation using resting-state EEG. Simplified sequence of resting-state functional connectivity analysis methods will be reviewed in this article. The outcomes from EEG resting-state connectivity analysis are comprised of connectivity itself of the specific condition and the network topology measure which describe the characteristics of specific connectivity. An increasing number of studies report the differences in the functional connection itself, global network measures including segregation (connectedness), integration (efficiency), and importance of specific nodes (centrality or node degree). Several issues that are relevant in the resting-state connectivity analysis are obtaining good quality EEG for analysis, consideration of particular features of EEG signal, understanding different types of association measures, and statistics for comparison of connectivities. Well-designed and carefully analyzed EEG resting-state connectivity analysis can provide useful information for patient care in pediatric neurology.
Brain ; Electroencephalography* ; Magnetic Resonance Imaging ; Magnetoencephalography ; Neurology ; Patient Care

Magnetoencephalography (MEG) records the magnetic field generated by electrical activity of cortical neurons. The signal is not distorted or attenuated, and it is contactless recording that can be performed comfortably even for longer than an hour. It has excellent and decent temporal resolution, especially when it is combined with the patient's own brain magnetic resonance imaging (magnetic source imaging). Data of MEG and electroencephalography are not mutually exclusive and it is recorded simultaneously and interpreted together. MEG has been shown to be useful in detecting the irritative zone in both lesional and nonlesional epilepsy surgery. It has provided valuable and additive information regarding the lesion that should be resected in epilepsy surgery. Better outcomes in epilepsy surgery were related to the localization of the irritative zone with MEG. The value of MEG in epilepsy surgery is recruiting more patients to epilepsy surgery and providing critical information for surgical planning. MEG cortical mapping is helpful in younger pediatric patients, especially when the epileptogenic zone is close to the eloquent cortex. MEG is also used in both basic and clinical research of epilepsy other than surgery. MEG is a valuable diagnostic modality for diagnosis and treatment, as well as research in epilepsy.
Brain ; Electroencephalography ; Epilepsy* ; Humans ; Magnetic Fields ; Magnetic Resonance Imaging ; Magnetoencephalography* ; Neurons ; Pediatrics

Lethal neonatal rigidity and multifocal seizure syndrome (RMFSL) is a severe autosomal recessive epileptic encephalopathy characterized by rigidity, intractable multifocal seizures, microcephaly, apnea, and bradycardia immediately after birth. RMFSL is related to a mutation in breast cancer 1-associated ataxia telangiectasia mutated activation-1 protein (BRAT1). We report a case of a female infant born to non-consanguineous Korean parents who developed hypertonia, dysmorphic features, progressive encephalopathy with refractory seizures at birth, and worsening intermittent apnea, leading to intubation and death at 137 days of age. The initial repeated electroencephalographic findings were normal; however, a pattern of focal seizures emerged at 35 days of life. Rapid trio whole-exome sequencing revealed heterozygous mutations c.1313_1314delAG p.(Gln438Argfs*51) and c.1276C>T p. (Gln426*) in BRAT1. After genetic counseling for pregnancy planning, a preimplantation genetic diagnosis for targeted BRAT1 mutations was successfully performed, and a healthy baby was born. To our knowledge, this is the first reported case of a Korean patient with compound heterozygous mutations in BRAT1. An early and accurate genetic diagnosis can help provide timely treatment to patients and indicate the need for reproductive counseling for parents for family planning.

Purpose: Congenital myasthenic syndrome (CMS) is a clinically and genetically heterogeneous group of disorders characterized by impaired neuromuscular transmission. This study aims to provide the clue for early diagnosis and improved therapeutic strategies in CMS. Materials and Methods: Through the targeted panel sequencing including twenty CMS causative genes, eleven patients were genetically confirmed and enrolled in this study. A retrospective medical record review was carried out for the clinical and laboratory data analysis. Results: The age of patients ranged from 5 to 23 years, with the median age of 16 years. The peak age at onset of symptoms was the neonatal period. Seven out of the eleven patients were symptomatic at birth. The most commonly reported initial finding was generalized hypotonia with poor sucking and crying. Mean time to accurate diagnosis was 9.3±5.0 years. Total fifteen different variants in seven genes associated with CMS (DOK7, AGRN, RAPSN, CHRNE, COLQ, SLC5A7, and GFPT1) were identified. Conclusion We describe the clinical and genetic characteristics of CMS patients and treatment outcome in a single tertiary center. High clinical suspicion and timely molecular diagnosis is particularly important for the tailored therapy to maximize clinical improvement in CMS.

Primary hypokalemic periodic paralysis (HOKPP) is an autosomal dominant disorder manifesting as recurrent periodic flaccid paralysis and concomitant hypokalemia. HOKPP is divided into type 1 and type 2 based on the causative gene. Although 2 different ion channels have been identified as the molecular genetic cause of HOKPP, the clinical manifestations between the 2 groups are similar. We report the cases of 2 patients with HOKPP who both presented with typical clinical manifestations, but with mutations in 2 different genes (CACNA1Sp.Arg528His and SCN4A p.Arg672His). Despite the similar clinical manifestations, there were differences in the response to acetazolamide treatment between certain genotypes of SCN4A mutations and CACNA1S mutations. We identified p.Arg672His in the SCN4A gene of patient 2 immediately after the first attack through a molecular genetic testing strategy. Molecular genetic diagnosis is important for genetic counseling and selecting preventive treatment.
Acetazolamide ; Genetic Counseling ; Genotype ; Humans ; Hypokalemia ; Hypokalemic Periodic Paralysis ; Ion Channels ; Molecular Biology ; Paralysis

Primary hypokalemic periodic paralysis (HOKPP) is an autosomal dominant disorder manifesting as recurrent periodic flaccid paralysis and concomitant hypokalemia. HOKPP is divided into type 1 and type 2 based on the causative gene. Although 2 different ion channels have been identified as the molecular genetic cause of HOKPP, the clinical manifestations between the 2 groups are similar. We report the cases of 2 patients with HOKPP who both presented with typical clinical manifestations, but with mutations in 2 different genes (CACNA1Sp.Arg528His and SCN4A p.Arg672His). Despite the similar clinical manifestations, there were differences in the response to acetazolamide treatment between certain genotypes of SCN4A mutations and CACNA1S mutations. We identified p.Arg672His in the SCN4A gene of patient 2 immediately after the first attack through a molecular genetic testing strategy. Molecular genetic diagnosis is important for genetic counseling and selecting preventive treatment.
Acetazolamide ; Genetic Counseling ; Genotype ; Humans ; Hypokalemia ; Hypokalemic Periodic Paralysis ; Ion Channels ; Molecular Biology ; Paralysis

Japanese encephalitis is one of the leading causes of acute encephalitis in Asia. But in Korea, the number of Japanese encephalitis cases has dropped considerably due to mass vaccination and vector control. Especially, there were no case reports under the age of 9 years during the last ten years. We will describe a case of a previously healthy 7-month old boy who presented with fever and seizure. The patient was diagnosed with Japanese encephalitis, based on the cerebrospinal fluid and serum antibody analyses for the Japanese encephalitis virus. Typical brain magnetic resonance image findings of Japanese encephalitis were observed. The patient received extensive conservative treatment including high dose intravenous corticosteroid treatment and immunoglobulin. In spite of severe hemodynamic instability, the patient survived, and he is currently in a vegetative state with respiratory assist by a home ventilator. Although the incidence of Japanese encephalitis dropped dramatically in Korea, pediatricians should always consider the diagnosis as one of the possibilities for patients with encephalitis, especially if the patient is not immunized for JEV. Since there is no specific treatment for JEV, timely and comprehensive conservative care is critical to reduce the mortality and morbidity.
Asia ; Asian Continental Ancestry Group* ; Brain ; Cerebrospinal Fluid ; Diagnosis ; Encephalitis ; Encephalitis Virus, Japanese ; Encephalitis, Japanese* ; Fever* ; Hemodynamics ; Humans ; Immunoglobulins ; Incidence ; Infant* ; Korea ; Male ; Mass Vaccination ; Mortality ; Persistent Vegetative State ; Seizures* ; Ventilators, Mechanical

BACKGROUND AND PURPOSE: There are few studies that have investigated predictive factors related to migraine prophylaxis of which produced inconsistent results. The aim of this study was to identify factors that can predict the treatment response to topiramate prophylaxis in pediatric patients with migraine. METHODS: One hundred and thirteen patients who were older than 7 years and received topiramate for at least 3 months were recruited from the Seoul National University Bundang Hospital outpatient clinic from 2005 to 2014. A positive response was defined as a reduction of more than 50% in the number of migraine episodes after topiramate treatment. Proposed predictive factors such as migraine characteristics including severity and frequency were assessed, as were other data on sex, disease duration, associated symptoms, family history, and impairment of daily activities. RESULTS: Seventy patients (61.9%) responded to prophylactic treatment with topiramate. Patients who experienced significant impairment in daily activities showed significant benefit from the treatment (p=0.004). Sex, the severity, frequency, and duration of migraine episodes, disease duration, treatment duration, age at onset, and associated symptoms were not significantly related to a response to topiramate treatment. CONCLUSIONS: Migraine characteristics and associated symptoms were not significantly related to a response to topiramate treatment. However, patients with significant impairment in daily activities showed significant benefit from the treatment, and so prophylactic topiramate treatment should be strongly encouraged in this patient group.
Age of Onset ; Humans ; Migraine Disorders* ; Outpatient Clinics, Hospital ; Seoul

PURPOSE: The purpose of this study was to evaluate the efficacy and tolerability of extended-release valproic acid once daily dosing in juvenile myoclonic epilepsy (JME). METHODS: Medical records of patients who received valproic acid monotherapy for the treatment of JME were retrospectively reviewed. Their clinical information regarding age, gender, seizure types, underlying neurologic status, dosing regimen, response to treatment, and adverse events related to valproic acid, were analyzed. Seizure control, compliance, and adverse events rates were compared between the group of once daily dosing and the group of twice daily dosing. RESULTS: Twenty one patients (11 boys and 10 girls) were included in the study. Twelve patients were taking valproic acid extended-release once daily and nine patients were taking twice a day. More than 50% decrease in myoclonic seizure was achieved in all the patients in both groups. Generalized tonic-clonic seizure was controlled in all the patients who were taking once daily while 3 patients (36%, 3/8 patients) in twice daily group had breakthrough generalized tonic clonic seizures during the 2 year period of treatment. However, there were no statistically significant differences in seizure control, compliance, and adverse event rates between the two groups. CONCLUSION: This study demonstrated that valproic acid extended-release once daily dosing was as effective and tolerable as twice daily in the treatment of JME. Once daily dosing of valproic acid would be convenient which improve patient compliance and consequently bring better outcome in treatment of JME.
Compliance ; Humans ; Medical Records ; Myoclonic Epilepsy, Juvenile* ; Patient Compliance ; Retrospective Studies ; Seizures ; Valproic Acid*

This study was performed to assess the usefulness of magnetoencephalography (MEG) as a presurgical evaluation modality in Korean pediatric patients with lesional localization-related epilepsy. The medical records and MEG findings of 13 pediatric patients (6 boys and 7 girls) with localization-related epilepsy, who underwent epilepsy surgery at Seoul National University Children's Hospital, were retrospectively reviewed. The hemispheric concordance rate was 100% (13/13 patients). The lobar or regional concordance rate was 77% (10/13 patients). In most cases, the MEG spike sources were clustered in the proximity of the lesion, either at one side of the margin (nine patients) or around the lesion (one patient); clustered spike sources were distant from the lesion in one patient. Among the patients with clustered spike sources near the lesion, further extensions (three patients) and distal scatters (three patients) were also observed. MEG spike sources were well lateralized and localized even in two patients without focal epileptiform discharges in the interictal scalp electroencephalography. Ten patients (77%) achieved Engel class I postsurgical seizure outcome. It is suggested that MEG is a safe and useful presurgical evaluation modality in pediatric patients with lesion localization-related epilepsy.
Adolescent ; Brain/radionuclide imaging ; Brain Diseases/pathology ; Child ; Child, Preschool ; Epilepsies, Partial/pathology/*surgery ; Female ; Ganglioglioma/pathology ; Humans ; Infant ; Magnetic Resonance Imaging ; *Magnetoencephalography ; Male ; Malformations of Cortical Development/pathology ; Neoplasms, Neuroepithelial/pathology ; Positron-Emission Tomography ; Retrospective Studies ; Seizures/diagnosis