OBJECTIVE: The abacus, first used in Asian countries more than 800 years ago, enables efficient arithmetic calculation via visuo-spatial configuration. We investigated whether abacus-trained children performed better on cognitive tasks and demonstrated higher levels of arithmetic abilities compared to those without such training. METHODS: We recruited 75 elementary school children (43 abacus-trained and 32 not so trained). Attention, memory, and arithmetic abilities were measured, and we compared the abacus with the control group. RESULTS: Children who had learned to use an abacus committed fewer commission errors and showed better arithmetic ability than did controls. We found no significant differences between children with and without abacus training in other areas of attention. CONCLUSION: We speculate that abacus training improves response inhibition via neuroanatomical alterations of the areas that regulate such functions. Further studies are needed to confirm the association between abacus training and better response inhibition.
Asian Continental Ancestry Group ; Case-Control Studies* ; Child ; Cognitive Science ; Humans ; Mathematics ; Memory

PURPOSE: Osteoarticular infections in children and adolescents are important because it can cause functional compromise if appropriate treatment is delayed. Therefore, this study was designed to describe the clinical presentations and causative organisms of osteoarticular infections in children and adolescents in order to propose early diagnosis method and an appropriate empiric antimicrobial therapy. METHODS: Forty-two medical records were reviewed retrospectively, which were confirmed as osteomyelitis (OM) or septic arthritis (SA) at Department of Pediatrics or Orthopedic Surgery in patients under 18 years old of Ewha Womans University Mokdong Hospital from March 2008 to March 2015. RESULTS: We identified 21 cases of OM, 13 cases of SA and 8 cases of OM with SA. There were 31 males and 11 females and mean age was 7.1 years old. The most common symptoms were pain and tenderness of involved site. Major involved bones were femur (10 cases, 34.5%), tibia (7 cases, 24.1%) and major involved joints were hip (9 cases, 42.9%), and knee (5 cases, 23.8%). Increased serum C-reactive protein and erythrocyte sedimentation rate were observed in 37 cases (88.1%) respectively. Magnetic resonance imaging was performed in 40 cases among 42 cases and was used to demonstrate osteoarticular infections and other adjacent infections. Nine cases (23.7%) among 38 cases and 20 cases (50.0%) among 40 cases were positive in blood culture and infected site culture respectively. The most common causative organism was Staphylococcus aureus, which was represented in 22 cases (75.9%), of which nine cases (40.9%) were resistant to methicillin. CONCLUSIONS: S. aureus was the most common causative organism of osteoarticular infections in children and adolescents and the proportion of MRSA was high in this study. Therefore, we recommend vancomycin as the first empiric antimicrobial therapy and suggest that further study is necessary to elucidate an appropriate guideline for treatment which takes into account MRSA proportion.
Adolescent* ; Arthritis, Infectious ; Blood Sedimentation ; C-Reactive Protein ; Child* ; Early Diagnosis ; Female ; Femur ; Hip ; Humans ; Joints ; Knee ; Magnetic Resonance Imaging ; Male ; Medical Records ; Methicillin ; Methicillin-Resistant Staphylococcus aureus ; Orthopedics ; Osteomyelitis ; Pediatrics ; Retrospective Studies* ; Staphylococcus aureus ; Tibia ; Vancomycin

Purpose: To examine the refractive errors, retinal manifestations, and genotype in tuberous sclerosis complex (TSC) patients in a Korean population. Materials and Methods: A total of 98 patients with TSC were enrolled in Severance Hospital for a retrospective cohort study. The number of retinal astrocytic hamartoma and retinal achromic patch within a patient, as well as the size, bilaterality, and morphological type were studied. In addition, the refractive status of patients and the comorbidity of intellectual disability and epilepsy were also examined. Results: Retinal astrocytic hamartoma was found in 37 patients, and bilateral invasion was observed in 20 patients (54%). TSC1 mutation was associated with myopia (p=0.01), while TSC2 mutation was associated with emmetropia (p=0.01). Retinal astrocytic hamartoma was categorized into three morphological types and examined as follows: type I (87%), type II (35%), and type III (14%). Single invasion of retinal astrocytic hamartoma was identified in 32% of the patients, and multiple invasions in 68%. The TSC1/ TSC2 detection rate was 91% (41/45). Among them, TSC1 variant was detected in 23 patients (54%), whereas TSC2 variant was detected in 18 patients (40%). The results showed that TSC2 mutations are correlated with a higher rate of retinal astrocytic hamartoma involvement (all p<0.05), and multiple and bilateral involvement of retinal hamartomas (all p<0.05). However, the size of retinal astrocytic hamartomas, comorbidity of epilepsy, or intellectual disability did not show correlation with the genetic variant. Conclusion TSC1 variant patients were more myopic, while TSC2 variant patients showed association with more extensive involvement of retinal astrocytic hamartoma.

Purpose: To evaluate the accuracy of the Kane formula for intraocular lens (IOL) power calculation in comparison with existing formulas by incorporating optional variables into calculation. Materials and Methods: This retrospective review consisted of 78 eyes of patients who had undergone uneventful phacoemulsification with intraocular implantation at Severance Hospital in Seoul, Korea between February 2020 and January 2021. The Kane formula was compared with six of the existing IOL formulas (SRK/T, Hoffer-Q, Haigis, Holladay1, Holladay2, Barrett Universal II) based on the mean absolute error (MAE), median absolute error (MedAE), and the percentages of eyes within prediction errors of ±0.25D, ±0.50D, and ±1.00D. Results: The Barrett Universal II formula demonstrated the lowest MAEs (0.26±0.17D), MedAEs (0.28D), and percentage of eyes within prediction errors of ±0.25D, ± 0.50D, and ±1.00D, although there was no statistically significant difference between Barrett Universal II-SRK/T (p=0.06), and Barrett Universal II-Kane formula (p<0.51). Following the Barrett Universal II formula, the Kane formula demonstrated the second most accurate formula with MAEs (0.30±0.19D) and MedAEs (0.28D). However, no statistical difference was shown between Kane-Barrett Universal II (p=0.51) and Kane-SRK/T (p=0.14). Conclusion Although slightly better refractory outcome was noted in the Barrett Universal II formula, the performance of the Kane formula in refractive prediction was comparable in IOL power calculation, marking its superiority over many conventional IOL formulas, such as HofferQ, Haigis, Holladay1, and Holladay2.

OBJECTIVES: Many studies have demonstrated comorbidities and overlapping symptoms in attention-deficit hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD). The purpose of this study was to examine the functional impairment in subjects with ADHD, ODD, and in those with both ADHD and ODD. METHODS: 172 male subjects, aged 6 to 15 years old, were enrolled in this study. Based on diagnoses made by applying the Kiddie-Schedule for Affective Disorders and Schizophrenia-Present and Lifetime (K-SADS-PL), the subjects were categorized into four groups: ADHD group (n=64), ODD group (n=17), ADHD+ODD group (n=28), and control group (n=63). The Child and Adolescent Functioning Impairment Scale (CAFIS) was used to measure the functional impairment of the subjects. CAFIS consists of four subscales : Family relationship, Teacher relationship, Peer relationship, and Academic achievement scales. A high CAFIS score implies high functional impairment. Analysis of covariance was conducted to compare the scores between the four groups. RESULTS: Both the ODD and the ADHD+ODD groups had significantly high scores for Parent relationship compared to that of the ADHD group. Compared to the control group, both the ADHD and the ADHD+ODD group had significantly higher scores for Peer relationship and Academic achievement, whereas, the ODD group showed no significant difference from the control group on those two subscales. CONCLUSION The present study showed that subjects with ADHD and ODD have different functional impairment characteristics. The subjects' relationships with their parents were worsened by the presence of ODD. Peer relationships and Academic achievements were significantly affected by the presence of ADHD.

OBJECTIVES: Kikuchi-Fujimoto disease (KFD) is characterized by lymphadenopathy and fever, and is usually self-limited. This study analyzed the clinical characteristics of pediatric patients with KFD. METHODS: This retrospective, observational, single-center study was conducted in South Korea from March 2008 to October 2015. KFD was diagnosed based on clinical, radiological or histological findings and excluded when there were any other causes of lymphadenopathy. Medical records were reviewed for clinical and laboratory manifestations. RESULTS: A total of 35 cases were included. The mean patient age was 12.1±2.9 years (range, 5 to 17 years); the male-to-female ratio was 1:0.8. The main clinical manifestations were cervical lymphadenopathy and fever in 34 cases (97%). The mean duration of fever was 12.2±8.3 days (range, 2 to 37 days). We noted enlargement of lymph nodes in the cervical, mesenteric (n=5, 14%), axillary (n=2, 6%), and inguinal (n=1, 3%) regions. Hepatosplenomegaly, loss of appetite, and rash were observed. On laboratory examinations, elevation of ferritin, leukopenia, and positivity for anti-nuclear antibodies were frequently observed. Twelve patients underwent biopsy and 23 cases were diagnosed by radiological findings. The mean duration of hospitalization for all cases was 7.9±2.9 days (range, 3 to 13 days) and steroids were administered in 10 cases. KFD recurrence was observed in 2 cases (5.7%) with the time to relapse of 7 months and 4 years. There were no cases with systemic lupus erythematous or other autoimmune disease. CONCLUSION: KFD should be considered in pediatric patients with lymphadenopathy and prolonged fever. Patients with KFD should be monitored for recurrence and the development of autoimmune disease.
Adolescent* ; Antibodies ; Appetite ; Autoimmune Diseases ; Biopsy ; Child* ; Exanthema ; Ferritins ; Fever ; Histiocytic Necrotizing Lymphadenitis* ; Hospitalization ; Humans ; Korea ; Leukopenia ; Lymph Nodes ; Lymphatic Diseases ; Medical Records ; Pediatrics ; Recurrence ; Retrospective Studies ; Steroids

Purpose: To compare anterior biometry measurements using placido-scanning-slit topography, rotating Scheimpflug tomography, and swept-source optical coherence tomography. Methods: A retrospective review consisted of 80 eyes of 49 participants who underwent anterior chamber depth (ACD), central corneal thickness (CCT), and keratometry examination on the same day. We used placido-scanning-slit topography (ORBscan II), rotating Scheimpflug tomography (Pentacam HR), and swept-source optical coherence tomography (CASIA SS1000). The intraclass correlation coefficients and Bland-Altman plots were used to evaluate the agreement and differences between measurements. Results: The mean ACD values were 2.88 ± 0.43, 2.82 ± 0.50, and 2.68 ± 0.44 mm; and the mean CCT values were 536.96 ± 31.19, 543.79 ± 31.04, and 561.41 ± 32.60 μm; and the mean keratometry (Km) were 43.81 ± 1.69, 43.81 ± 1.77, and 44.65 ± 1.95 diopters; as measured by CASIA SS-1000, Pentacam HR, and ORBscan II, respectively. Among the three devices, ACD was deepest to shallowest in the order of CASIA SS-1000, Pentacam HR, and ORBscan II (p < 0.05). The CCT was thickest to thinnest in the order of ORBscan II, Pentacam HR, and CASIA SS-1000 (p < 0.05). No significant differences in Km values were examined between CASIA SS-1000 and Pentacam HR, whereas ORBscan II overestimated Km with a statistically significant difference compared to the other two devices. Conclusions High level of agreement was found between CASIA SS-1000 and Pentacam HR for anterior parameters, including ACD, CCT, and Km, suggesting interchangeability. However, ORBscan II measurements differed considerably with the measurements obtained from the other two devices; therefore, it should not be used interchangeably. However, further studies with repeatability test should be considered in order to elucidate the reliability of each device.

Purpose: We investigated the feasibility of preoperative 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/ computed tomography (CT) radiomics with machine learning to predict microsatellite instability (MSI) status in colorectal cancer (CRC) patients. Materials and Methods: Altogether, 233 patients with CRC who underwent preoperative FDG PET/CT were enrolled and divided into training (n=139) and test (n=94) sets. A PET-based radiomics signature (rad_score) was established to predict the MSI status in patients with CRC. The predictive ability of the rad_score was evaluated using the area under the receiver operating characteristic curve (AUROC) in the test set. A logistic regression model was used to determine whether the rad_score was an independent predictor of MSI status in CRC. The predictive performance of rad_score was compared with conventional PET parameters. Results: The incidence of MSI-high was 15 (10.8%) and 10 (10.6%) in the training and test sets, respectively. The rad_score was constructed based on the two radiomic features and showed similar AUROC values for predicting MSI status in the training and test sets (0.815 and 0.867, respectively; p=0.490). Logistic regression analysis revealed that the rad_score was an independent predictor of MSI status in the training set. The rad_score performed better than metabolic tumor volume when assessed using the AUROC (0.867 vs. 0.794, p=0.015). Conclusion Our predictive model incorporating PET radiomic features successfully identified the MSI status of CRC, and it also showed better performance than the conventional PET image parameters.

Background: The persistent coronavirus disease 2019 (COVID-19) pandemic has had direct and indirect effects on mortality, making it essential to analyze excess mortality to fully understand the impact of the pandemic. In this study, we constructed a mathematical model using number of deaths from Statistics Korea and analyzed excess mortality between 2020 and 2022 according to age, sex, and dominant severe acute respiratory syndrome coronavirus 2 variant period. Methods: Number of all-cause deaths between 2010 and 2022 were obtained from the annual cause-of-death statistics provided by Statistics Korea. COVID-19 mortality data were acquired from the Korea Disease Control and Prevention Agency. A multivariate linear regression model with seasonal effect, stratified by sex and age, was used to estimate the number of deaths in the absence of COVID-19. The estimated excess mortality rate was calculated. Results: Excess mortality was not significant between January 2020 and October 2021.However, it started to increase monthly from November 2021 and reached its highest point during the omicron-dominant period. Specifically, in March and April 2022, during the omicron BA.1/BA.2-dominant period, the estimated median values for excess mortality were the highest at 17,634 and 11,379, respectively. Both COVID-19-related deaths and excess mortality increased with age. A notable increase in excess mortality was observed in individuals aged ≥ 65 years. In the context of excess mortality per 100,000 population based on the estimated median values in March 2022, the highest numbers were found among males and females aged ≥ 85 years at 1,048 and 910, respectively. Conclusion This study revealed that the prolonged COVID-19 pandemic coupled with its high transmissibility not only increased COVID-19-related deaths but also had a significant impact on overall mortality rates, especially in the elderly. Therefore, it is crucial to concentrate healthcare resources and services on the elderly and ensure continued access to healthcare services during pandemics. Establishing an excess mortality monitoring system in the early stages of a pandemic is necessary to understand the impact of infectious diseases on mortality and effectively evaluate pandemic response policies.