INTRODUCTION: Detrended fluctuation analysis (DFA) is used as a way of studying nonlinearity of EEG. In this study, DFA is applied on sleep EEG of normal subjects to look into its nonlinearity in terms of EEG channels and sleep stages. METHOD: Twelve healthy young subjects (age: 23.8+/-2.5 years old, male:female=7:5) have undergone nocturnal polysomnography (nPSG). EEG from nPSG was classified in terms of its channels and sleep stages and was analyzed by DFA. Scaling exponents (SEs) yielded by DFA were compared using linear mixed model analysis. RESULTS: Scaling exponents (SEs) of sleep EEG were distributed around 1 showing long term temporal correlation and self-similarity. SE of C3 channel was bigger than that of O1 channel. As sleep stage progressed from stage 1 to slow wave sleep, SE increased accordingly. SE of stage REM sleep did not show significant difference when compared with that of stage 1 sleep. CONCLUSION: SEs of Normal sleep EEG showed nonlinear characteristic with scale-free fluctuation, long-range temporal correlation, self-similarity and self-organized criticality. SE from DFA differentiated sleep stages and EEG channels. It can be a useful tool in the research with sleep EEG.
Electroencephalography* ; Polysomnography ; Sleep Stages ; Sleep, REM

INTRODUCTION: Excessive daytime sleepiness and cataplexy are key features of narcolepsy. Modafinil is psychostimulant used in the treatment of narcolepsy. In this study, we evaluated effects of modafinil on nocturnal sleep structure and sleep latency in multiple sleep latency test and clinical features. METHODS: Twelve narcoleptic patients (7 male, age: 22.9 +/- 2.6 yrs) were participated in the study. All of them had done nocturnal polysomnography (nPSG), multiple sleep latency test (MSLT), clinical symptoms scales and have repeated same procedure after taking 200 mg of modafinil. We have done linear mixed model analysis to describe effects of group, medication and nap time on these measures. RESULTS: Modafinil did not affect clinical scales except PSQI which had been reduced after medication. In this study, Modafinil reduced total sleep time, sleep efficiency and increased wake after sleep onset and percent of arousal during sleep in nocturnal polysomnography and prolonged mean sleep latency in multiple sleep latency tests in both group. DISCUSSION: Modafinil has stimulant effect of central nervous system but its effect on night sleep is less than other psychostimulants such as methylphenidate. We ascertained that modafinil affected total sleep time, sleep efficiency and percent of wake during sleep but did not effect on sleep structure. Modafinil was effective in the management of day time sleepiness. Modafinil can enhance alertness of control group without day time sleepiness.
Arousal ; Cataplexy ; Central Nervous System ; Humans ; Male ; Methylphenidate ; Narcolepsy* ; Polysomnography ; Weights and Measures

Transhiatal gastric transpositions were performed in two case of long gap esophageal atresia without tracheoesophageal fistula. The patients were a 12 months old female and an 18 months old male. Stamm type gastrostomies were performed at other hospitals in both cases. The stomach was mobilized preserving the right gastric artery, the right gastroepiploic artery and spleen. The proximal and distal esophageal pouches were excised by transcervical and transhiatal route, respectively. The mobilized stomach was pulled up to the neck through esophageal hiatus and posterior mediastinal route. The esophagogastrostomy, the only one anastomosis of this procedure, was performed in the neck. There was no clinical evidence of anastomotic leakage, stricture, regurgitation, difficulty of gastric emptying, hoarseness or respiratory problem. Transhiatal gastric transposition seems to be a safe and easy alternative surgical procedure for esophageal replacement in long gap esophageal atresia.
Anastomotic Leak ; Arteries ; Constriction, Pathologic ; Esophageal Atresia* ; Female ; Gastric Emptying ; Gastroepiploic Artery ; Gastrostomy ; Hoarseness ; Humans ; Infant ; Male ; Neck ; Spleen ; Stomach ; Tracheoesophageal Fistula

OBJECTIVE: The purpose of this paper is to study the possible differences in clinical and polysomnographic findings, depending on the presence or absence of subjective complaints of abnormal sleep behavior, in patients with RWA on polysomnography. METHOD: We reviewed patient records and polysomnographic data of patients referred to the Sleep Laboratory at Seoul National University Hospital from June 1996 through October 2002. We defined the manifest RBD group (n=32) as patients having both complaints of abnormal sleep behavior and RWA on polysomnography. The latent RBD group (n=20) consisted of patients who exhibited RWA on polysomnography but did not complain of abnormal sleep behavior. The clinical characteristics and polysomnographic findings between the two groups were compared and analyzed. RESULTS: Fifty-two subjects had RWA, as detected by polysomnography (42 males and 10 females, mean age of 55.1+/-19.1 years). Subjects in the manifest RBD group were significantly older than those in the latent RBD group (61.59+/-13.5 vs. 44.70+/-2.76 years, independent t-test, p<0.01). More subjects in the manifest RBD group exhibited abnormal REM behavior on polysomnography than did subjects in the latent RBD group (81.3 vs. 50.0%, Fisher's exact test, p<0.05). No significant differences between the groups were found in the prevalence of brain disorders and primary sleep disorders, gender proportion, and sleep architecture. CONCLUSION: No difference in sleep architecture was found between the manifest and the latent RBD groups. Only age and the presence of abnormal sleep behavior on polysomnography differentiated the two groups. We suggest that RWA on polysomnography without complaints of abnormal sleep behavior may be early manifestation of manifest RBD. Attention to RWA on polysomnography is necessary to help prevent full-blown RBD from developing.
Brain Diseases ; Female ; Humans ; Male ; Mental Disorders* ; Polysomnography ; Prevalence ; REM Sleep Behavior Disorder ; Seoul ; Sleep Wake Disorders ; Sleep, REM*

OBJECTIVE: The purpose of this study is to investigate the prevalence rate of OSA in subjects whose main sleep complaint is insomnia and to find differential factors of OSA in these insomniac subjects. METHOD: We reviewed the medical records and polysomnographic findings of patients referred to the Sleep Laboratory at Seoul National University Hospital from January 1996 to December 2002. Four-hundred and seventy subjects complained of insomnia as their main sleep problem (235 males and 235 females, mean age 53.6+/-12.4 years). First, we investigated the prevalence rate of OSA in these insomniac patients. Second, we compared the clinical and demographic characteristics of the OSA-associated group with those of the non-associated group. Third, we examined whether the degree or presence of differential factors within the OSA group correlate with severity of OSA, as determined by the respiratory disturbance index (RDI). RESULTS: Among 470 insomniac subjects, 125 subjects (26.6%) were diagnosed as OSA by nocturnal polysomnography. OSA-associated subjects were significantly older (58.4+/-12.3 years vs. 51.8+/-11.2 years, p<0.01), and had significantly higher body mass index (BMI) (23.4+/-3.3 kg/m2 vs. 22.5+/-3.1 kg/m2, p=0.44) than non-associated subjects. The OSA-associated group had more subjects with male gender (64.0 % vs. 44.9 %, p<0.01), hypertension (20.0 % vs. 9.3 %, p<0.01) or snoring (96.0 % vs. 63.5 %, p<0.01). Within the OSA-associated group, age had a significant positive correlation with RDI (p=0.01). CONCLUSION: We found that a considerable portion of patients complaining of insomnia as their main sleep problem were diagnosed as OSA. Snoring, old age, male gender, obesity, and comorbid hypertension were found to be differential factors of OSA in insomniac patients. We suggest that diagnostic efforts including nocturnal polysomnography are needed for insomniac patients with any of the above risk factors of OSA.
Body Mass Index ; Female ; Humans ; Hypertension ; Male ; Medical Records ; Obesity ; Polysomnography ; Prevalence ; Risk Factors ; Seoul ; Sleep Apnea, Obstructive* ; Sleep Initiation and Maintenance Disorders* ; Snoring

No abstract available.
Cushing Syndrome*

Data collection is a major problem in large scale clinical studies, especially muticenter and international trials. Data collection by mailing is too slow and expensive. Furthermore, difficulty in understanding handwritten notes from many investigators could result in potential errors in data entry. We developed web-based data collection system for patterns of care study of radiation oncology to collect data nation-widely and efficiently. We introduced drop-down box, check box, and radio button in data entry form for rapid, convenient and correct data entry. Our system also checks blank item, logical errors and other validity of data in real time. For security, we committed the server to the care of Korea Internet Data Center, implemented secure socket layer for communication between web server and clients, and established two remote backup systems. Participating investigators are satisfied with this system and we are collecting data efficiently. We think that web-based data collection system should be considered in any large scale clinical studies.
Data Collection* ; Humans ; Internet ; Korea ; Logic ; Postal Service ; Radiation Oncology* ; Research Personnel

No abstract available.
Neurofibromatoses* ; Pseudarthrosis* ; Radius*

The tibial pilon fracture has been described as difficult fracture to manage. We have reviewed 23 cases of tibial pilon fractures from Mar. 1987 to Feb. 1993 at our hospital. 1. The fractures were classified into five types according to the system of Ovadia and Beals and the methods of treatment were divided into two groups; 9 cases were treated with Ilizarov device(Group I). 6 cases out of Group I were type 3, 4 and 5. Other methods were performed in 14 cases(Group II). 8 cases out of Group II were type 3, 4, and 5. 2. In type 3, 4 and 5 fractures, there were 86 per cent good and fair radiographic results in Group I and 63 per cent good and fair results in Group II. 3. Satisfactory results were obtained by the treatment of Ilizarov method especially in type 3, 4 and 5 fractures. The advantages of Ilizarov device were its primary reduction with ligamentotaxis, easy open reduction due to proximal and distal stabilization, minimal soft tissue injury and minimal internal fixation.
Ilizarov Technique ; Soft Tissue Injuries

BACKGROUND: Aging is associated with increased cardiovascular risk and firmly established as a risk factor for the development of atherosclerosis. However the exact mechanism of age-related damage to the arterial wall and its relation to the atherosclerotic process are not well known.The endothelium plays an important role for the regulation of vascular tone and the endothelial function is impaired in the presence of risk factors early in the process of atherosclerosis. Assessment of endothelial function appears to be a valuable tool for the diagnosing and therapeutic monitoring of coronary artery disease. Anti-oxidants are known to improve endothelial dysfunction in atherosclerosis patients. The aim of this study was, (1) to evaluate the endothelial function in elderly, (2) to investigate whether vitamin C administration has benefit on the endothelial function in elderly. METHODS: The endothelial function was estimated using venous occlusion plethysmography(VOP) in 7 elderly and 7 young healthy volunteers. The strain guage was connected to plethysmograph to record the forearm volume change. A rapid cuff inflator was used to inflate the arm cuff to 40 mmHg instantaneuosly thus occluding venous return from the forearm. The measurement of forearm volume change was repeated for 7 times each stage. The change of the forearm blood flow(FBF) was measured with the acetylcholine infusion through brachial artery and also with intra-arterial vitamin C. RESULTS: Endothelium-dependent vasodilatation was significantly impaired in the elderly group compared to the young group(321 +/-17% in elderly group vs 509 +/-81%, mean+/-SEM) Forearm blood flow response to acetylcholine was significantly enhanced with inraarterial infusion of vitamin C in elderly group(321+/-17% in elderly group vs 78% in vitamin C) Coinfusion of L-NMMA, an inhibitor of nitric oxide synthase, blunted forearm blood flow response to acetylcholine. CONCLUSIONS: Even though the mechanisms leading to drpressed endothelial function in elderly remains to be elucidated, our study shows that vitamin C result in demonstrable improvement by a mechanism that is probably related to antioxidant activity.
Acetylcholine ; Aged* ; Aging ; Arm ; Ascorbic Acid* ; Atherosclerosis ; Brachial Artery ; Coronary Artery Disease ; Endothelium ; Forearm ; Healthy Volunteers ; Humans ; Nitric Oxide Synthase ; omega-N-Methylarginine ; Risk Factors ; Vasodilation* ; Vitamins*