Objectives : The detrended fluctuation analysis is one of the nonlinear methods for the investigation of biological time series. It quantifies the fractal scaling properties and is known to be useful in the evaluation of long-range correlations in time series. The heart rate variability(HRV) of obstructive sleep apnea syndrome (OSAS) patients during nighttime was analyzed by detrended fluctuation analysis to assess its relationship with the severity of the symptoms. Methods : Fifty nine untreated male OSAS patients with moderate to severe symptoms(mean age=45.4${\pm}$11.7 years, apnea-hypopnea index, AHI${\geq}$15) underwent nocturnal polysomnography. Moderate(AHI=15-30, N=22) and severe(AHI>30, N=37) OSAS patients were compared for the indices derived from detrended fluctuation analysis and frequency domain analysis of HRV. Results : In the detrended fluctuation analysis, the alpha values were 0.75${\pm}$0.11 and 0.82${\pm}$0.07 for the severe and the moderate OSAS groups respectively. The difference was significant(p<.01). The alpha value had negative correlation with AHI(r=-.425, p=.001). Negative correlation coefficients were also found in the relationships between the alpha values and very low frequency(VLF)(r=-.425, p=.001), low frequency(LF)(r=-.633, p= <.001) and the LF/HF ratio(r=-.305, p=.019) respectively. LF/HF ratio(p=.005) was higher in the severe OSAS group compared to that of the moderate OSAS group. Conclusion : In this study, the detrended fluctuation analysis showed the significant difference between the two OSAS groups classified according to their severity of symptoms. The scaling exponent showed the negative correlation with AHI and indicies of frequency domain analysis. This result suggests that detrended fluctuation analysis can be helpful to estimate the severity of OSAS.

Objectives : The purpose of this study was to develop the Korean version of the Social Functioning Scale (KSFS) in the patients with schizophrenia. Methods : KSFS was administered to 90 schizophrenic patients and 80 their parents and 90 normal controls for examining the reliability and validity. Results : Data analysis showed statistically significant reliabilities and validities of KSFS. The test-retest reliability, rater vs. self-report reliability, and internal consistency for total scores of KSFS were 0.93, 0.44 and 0.94 respectively. Evidence for discriminant validity of KSFS comes from the results that the mean scores of schizophrenic patients were significantly higher than those of normal controls. Construct validity was assessed by calculating the 7 inter-areas correlations of the KSFS, and all areas were statistically significant. Significant correlations between the total scores of KSFS and those of SOFAS lend support for the concurrent validity of this instrument. Factor analyses were performed and two factors were extracted accounting for 63.7% of the variance. Sensitivity was assessed indirectly via the distribution and range of scores on the SFS. The normal control group showed a distribution around a higher mean with a moderate positive skew. Conclusion : KSFS was found to be a valid, reliable, and sensitive instrument which can be used to evaluate the degree of social functioning in the patients with schizophrenia.

Objectives : Depression is a common psychiatric disorder in cancer patients. The Brief Edinburgh Depression Scale(BEDS), which is an abbreviated version of the Edinburgh Depression Scale, may serve as a useful tool in screening for the depression in patients with the medical illnesses. This report investigated the reliability and validity of the Korean Version of the BEDS(K-BEDS) for the depression in cancer patients. Methods : One-hundred cancer patients were enrolled in this study. All subjects completed the K-BEDS, the Hospital Anxiety Depression Scale(HADS), and the Karnofsky Performance Status Scale(KPSS). Reliability, validity and Receiver Operating Characteristic(ROC) curve analysis measures were assessed. Results : The K-BEDS showed good internal consistency(Cronbach ${\alpha}$=0.77) and test-retest reliability(0.94, p<0.001). All item-total correlations were above 0.3. Also, it revealed moderate correlation with the depression subscale of the HADS(r=0.617), but no correlation with the KPSS. Exploratory factor analysis produced only one factor, accounting for 47.1% of the total variance. The most valid cutoff value to screen for depression was a total score of 5 on the K-BEDS, which showed sensitivity of 62.5% and specificity of 86.4% with a positive predictive value of 4.60 and a negative predictive value of 0.43.

Objectives : The serotonin transporter gene(SLC6A4) is one of the most widely studied candidate genes in autism spectrum disorder(ASD), but there have been conflicting results from studies into the association between SLC6A4 and ASD. The aim of this study was to evaluate the association between single nucleotide polymorphisms(SNPs) in the SLC6A4 gene and ASD in the Korean population. Methods : We selected 12 SNPs in SLC6A4 and observed the genotype of 151 Korean ASD trios. We tested the family-based association for each individual polymorphism and haplotype by using the standard TDT method in Haploview(http://www.broad.mit.edu/mpg/haploview/). Results : Through transmission-disequilibrium testing and haplotype analysis, we could not find any statistically significant transmitted allele or haplotype. In addition, a case-control association test with Korean HapMap data did not reveal any statistical significance. Conclusion : Although serotonin-related genes must be considered candidate genes for ASD, we suggest that common SNPs of SLC6A4 are not important markers for associations with Korean ASD.

Marchiafava-Bignami disease(MBD) is a rare complication of chronic alcoholism characterized by symmetrical demyelination of the corpus callosum. We report a case of MBD in a Korean patient having chronic alcohol dependence. The patient exhibited mental depression, weakness of all four limbs and dysarthria. Laboratory data showed mild hyponatremia. Magnetic resonance imaging(MRI) revealed unusual symmetrical resolving lesions of the putamen in addition to the typically observed lesion of the corpus callosum. The neurologic disturbances were gradually improved with the normalization of low plasma sodium levels. Marked improvement of abnormal MRI findings was noted after thiamine supplement, though the patient still exhibited severe cognitive impairment.