OBJECTIVE: Among various methods developed to quantitatively explore electroencephalograms (EEG), we focused on a wavelet method that was known to yield robust results under nonstationary conditions. The aim of this study was thus to introduce the wavelet method and demonstrate its potential use in clinical sleep studies. METHOD: This study involved artificial EEG specifically designed to validate the wavelet method. The method was performed to obtain time-dependent spectral power and phase angles of the signal. Synchrony of multichannel EEG was analyzed by an order parameter of the instantaneous phase. The standard methods, such as Fourier transformation and coherence, were also performed and compared with the wavelet method. The method was further validated with clinical EEG and ERP samples available as pilot studies at academic sleep centers. RESULT: The time-frequency plot and phase synchrony level obtained by the wavelet method clearly showed dynamic changes in the EEG waveforms artificially fabricated. When applied to clinical samples, the method successfully detected changes in spectral power across the sleep onset period and identified differences between the target and background ERP. CONCLUSION: Our results suggest that the wavelet method could be an alternative and/or complementary tool to the conventional Fourier method in quantifying and identifying EEG and ERP biomarkers robustly, especially when the signals were nonstationary in a short time scale (1-100 seconds).
Biomarkers ; Electroencephalography ; Fourier Analysis ; Pilot Projects

No abstract available.

No abstract available.
Genetics* ; Hyperaldosteronism*

No abstract availalbe.
Heart Failure* ; Heart*

Sleep is an essential process maintaining the life cycle of the human. In parallel with physiological, cognitive, subjective, and behavioral changes that take place during the sleep, there are remarkable changes in the electroencephalogram (EEG) that reflect the underlying electro-physiological activity of the brain. However, analyzing EEG and relating the results to clinical observations is often very hard due to the complexity and a huge data amount. In this article, I introduce several linear and non-linear tools, developed to analyze a huge time series data in many scientific researches, and apply them to EEG to characterize various sleep states. In particular, the spectral analysis, detrended fluctuation analysis (DFA), and synchrony analysis are administered to EEG recorded during nocturnal polysomnography (NPSG) processes and daytime multiple sleep latency tests (MSLT). I report that 1) sleep stages could be differentiated by the spectral analysis and the DFA; 2) the gradual transition from Wake to Sleep during the sleep onset could be illustrated by the spectral analysis and the DFA; 3) electrophysiological properties of narcolepsy could be characterized by the DFA; 4) hypnic jerks (sleep starts) could be quantified by the synchrony analysis.
Brain ; Electroencephalography ; Humans ; Hypogonadism ; Life Cycle Stages ; Mitochondrial Diseases ; Narcolepsy ; Ophthalmoplegia ; Polysomnography ; Sleep Stages

PURPOSE: Recently, two tests are commercially available for the identification of latent tuberculosis infection (LTBI): tuberculin skin test (TST) and interferon-gamma release assay (IGRA). Due to its false positiveness, TST tends to be preferred by IGRA until now. In our study, we simultaneously performed both TST and QuantiFERON(R)-TB Gold In-Tube (QFT-GIT) and compared their results. METHODS: TST and QFT-GIT were done for the diagnosis of LTBI among children who visited pediatric out-patient clinic at St. Vincent's Hospital, The Catholic University of Korea from February of 2007 to May of 2008. The study group was stratified into two groups in terms of whether there was intrafamilial contact or not. RESULTS: Out of total 35 children, 29 were tuberculosis (TB)-exposed cases and the remainders were diagnosed as clinical pulmonary TB. Among these 29 children, TST was positive 38.9% (7/18) for the intrafamilial and 45.5% (5/11) for the non-intrafamilial, and at the same time, the result for QFT-GIT was positive 5.6% (1/18) and 9.1% (1/11), respectively which implies that TST was more sensitive than QFT-GIT. Among 29 TB-exposed cases, 26 initially went through TST and QFT-GIT together on their first visit to out-patient clinic, and 15 continued the follow-up tests. Out of total 41 cases collected, the agreement (known as kappa value) was 0.063 which was relatively low. Including 6 cases with pulmonary TB who were all positive for TST and only 5 being positive for QFT-GIT, the final kappa value was 0.334. CONCLUSION: In our study, the agreement for TST and QFT-GIT was low, and the majorities were almost the cases of positive TST. In current situation with lacking a gold standard test and limited data on children to adolescents, this result is quite alarming that the recent trend tends to replace TST by QFT-GIT when diagnosing LTBI.
Adolescent ; Child ; Follow-Up Studies ; Humans ; Interferon-gamma Release Tests ; Korea ; Latent Tuberculosis ; Outpatients ; Skin ; Skin Tests ; Tuberculin ; Tuberculosis

No Abstract Available.
Retinal Detachment* ; Retinal Perforations* ; Retinaldehyde*

We have retrospectively analyzed the clinical and radiological outcome in 22 cervical spondylotic myeloradiculopathy patients who underwent combined front anterior decompression and fusion) and back (open door laminoplasty) surgery between Mar. 1991 and Jan. 1995. Clinical symptoms were evaluated by Japanese Orthopaedic Association(JOA) score and the recovery rate. Plain radiogram and MIR were taken before and after surgery, and then the cervical curvature, change of body to canal ratio and the A-P compression ratio of the cord were measured and compared to the clinical symptoms. Results : The mean JOA score increased from 10.1±3.3 preoperatively to 14.7±1.4 at the final follow-up with a mean recovery rate of 64.4%. No patients deteriorated as a result of the combined procedure. Post-op. radiograms showed an increasement of body to ratios (average 0.69±0.09 pre-op. to 1.0±0.13 post-op.) and maintenance or recovery of cervical Lordosis. On MRI, the A-P compression ratios of the cord were increased with recovery of subarachnoid space after the operation in most cases (average 38.4±7.6 pre-op. to 55.7±7.2 post-op.). Conclusion : This combined procedure safely and effectively resulted in decompression of the spinal cord and good functional recovery in patients with 1) anterior and posterior pathology, 2) narrow spinal canal and large spondylotic bar or herniated disc encroaching the spinal canal more than 5mm, 3) narrow spinal canal and kyphotic deformity, 4) narrow spinal canal and segmental instability, 5) multisegmental cord compression and severe radiculopathy.
Animals ; Asian Continental Ancestry Group ; Congenital Abnormalities ; Decompression ; Follow-Up Studies ; Humans ; Intervertebral Disc Displacement ; Lordosis ; Magnetic Resonance Imaging ; Pathology ; Radiculopathy ; Retrospective Studies ; Spinal Canal ; Spinal Cord ; Subarachnoid Space

No abstract available.
Jaw*

BACKGROUND: Methylmalonic aciduria can be caused by inherited defects in the methylmalonyl-CoA mutase enzyme, Inherited defects in the metabolism of vitamin Bl2 and acquired or inherited vitamin Bl2 deficiency. Quantitation of urinary methylmalonic acid (MMA) is very useful In diagnosis of methylmalonic acidemia and cobalamin deficiency. We evaluated a quantitation method of urinary MMA and determined reference values. METHODS: The method involved stable isotope dilution gas chromatographymass spectrometry (GC-MS) with (methyl 2H3)-MMA as the internal standard. We determined the detection limit, linearity and periodic variations of the assay. Urinary MMA levels were measured in 70 individuals of ages newborn to 58 years with no metabolic disorders. RESULTS: The lower limit of detection calculated from blank runs (mean+/-3SD) was 2.62nmo1/m1. One control urine tramp)e analyzed 23 times within 3 weeks game results of 7.83+/-1.09 (mean+/-SD, CV=13.8%) nmol/mL. The linearity at four different concentrations of MMA was acceptable (R2=0.9992). The concentration of urinary MMA in 70 individuals was 2.33+/-2.19 mmol/mol creatinine (mean+/-SD). Age related reference values which decreased with age were also reported (p=1.23x10-9). CONCLUSIONS: The described method is sensitive, specific and noninvasive, which is considered the gold standard method for measuring MMA. The method could be used as a screening test for cobalamin deficiency and inherited methyl malonic acidemia. On the basis of the narrow range of normal concentration, it is expected that the method would readily detect mild cobalamin deficiency.
Chromatography, Gas* ; Creatinine ; Diagnosis ; Gas Chromatography-Mass Spectrometry* ; Humans ; Infant, Newborn ; Limit of Detection ; Mass Screening ; Metabolism ; Methylmalonic Acid* ; Methylmalonyl-CoA Mutase ; Reference Values ; Spectrum Analysis ; Vitamin B 12 ; Vitamins