• Journal of Yeungnam Medical Science
• /
• v.7 no.2
• /
• pp.89-96
• /
• 1990

The purpose of this article was to determine the discriminant function analysis of the Korean Wechsler Intelligence Scale(KWIS) for 110 normal controls and 98 schizophrenics. Of special interest was to verify the clinical discriminant power of two subtests of the KWIS(Vacabulary and Digit Symbols) and Zung' s Self-rating Anxiety Scale(SAS). Four major hypotheses were postulated. The normal control group would show higher scores than the schizophrenics ; mean scores on both Vocabulary and Digit Symbol. The mean difference in Digit Symbol between the two groups would be greater than that in the Vacabulary. There would be no significant relation among Digit Symbol. Vacabulary. and Anxiety. The most powerful discriminant power would be expected from subtest of Digit Symbol. The mean discriminant scores were - 1.34425 for the control subjects. 1.34425 for the schizophrenics. The correctly discriminated percentage was 89.1% for the control subjects. 90.8% for the schizophrenics. From the findings it was concluded that both Digit Symbol and Vocabulary scales had strong diagnostic value but the former was more powerful than the latter. However. the Anxiety scales had less diagnostic value.

• Journal of Preventive Medicine and Public Health
• /
• v.27 no.3 s.47
• /
• pp.487-504
• /
• 1994

A cross-sectional study was performed to evaluate the effects of chronic low-dose solvent on neurobehavioral performance of 118 male car painters. A control group of 113 workers matched for age was selected from different sections of the factory. The mean age and the mean duration of employment were 33 years and 6.7 years in both groups. Mean years of education were 11.4 years in car painters and 11.8 years in controls. Each worker completed a medical and occupational questionnaire and four tests of Swedish performance evaluation system. These included simple reaction time, symbol digit, digit span and finger tapping speed. Althougth the mean duration of employment was 6.7 years, comparison of mean performance showed a significantly poorer performance on simple reaction time (p<0.05), symbol digit(p<0.01) and digit span(p<0.05) in car painters. In univariate analysis, age and educational level contributed to poorer performance on symbol digit and digit span. Smoking appeared to slow finger tapping speed in car painters. Performance of four tests of car painters exposed to high level of solvent was poorer than that of car painters exposed to low level. In multiple regression models, controlling for age, alcohol, smoking and shift work, solvent exposure was found to be associated with performance of simple reaction time, symbol digit and digit span and exposure to high level of solvent was related to poorer performance of symbol digit and digit span.

• Journal of Preventive Medicine and Public Health
• /
• v.31 no.4 s.63
• /
• pp.692-707
• /
• 1998

Aim. A neurobehavioral test for workers exposed to organic solvents in the workplace can be affected by many factors : age, education, motivation, ethnicity, etc. To apply more suitable neurobehavioral test for Korean workers, we evaluated the validity of several items of computerized and traditional neurobehavioral tests. Methods. We have applied eleven tests : four items of computerized neurobehavioral test(Swedish Performance Evaluation System) including Addition, Symbol-Digit, Dig-it Span, and Finger tapping speed, and seven items of traditional neurobehavioral test consisting of Addition, Digit-Symbol, Digit Span, Benton visual retention test, Pursuit aiming, Pegboard, and Tapping. These tests were performed on 96 workers exposed to solvents, and 100 reference workers. The concurrent and construct validities were evaluated by group difference, correlation with age, educational level, hippuric acid level, neurotoxic symptom, current exposure level, multitrait-multimethod matrix, fator analysis, and discriminant analysis. Results. Statistically significant differences were observed between the workers exposed to solvents and referents in computerized Symbol-Digit, Finger tapping speed, traditional Digit-Symbol and Pegboard. The computerized Symbol-Digit, traditional Digit-Symbol, Addition, Benton visual retention test, and Pegboard were found to be related to the age. The performance of computerized Symbol-Digit, Addition, and traditional Digit-Symbol were found to be related to the educational level significantly. The computerized Symbol-Digit, Finger tapping speed, and traditional Digit-Symbol were found to be related to hippuric acid, and neurotoxic symptom. The discriminability of Finger tapping speed, and Pegboard was better than the other tests. In discriminant analysis, the model with two variables, the computerized Symbol-Digit and Pegboard, classified almost 70 percent of the workers correctly. Conclusions. These results suggest that the computerized Symbol-Digit, Finger tapping speed, and Pegboard are more satisfactory for our purpose, and the Addition, Tapping, Benton visual retention test, and Pursuit aiming are less valid than other items. These may allow the reasonable selection of core neurobehavioral tests for workers exposed to solvents in Korea.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.3
• /
• pp.1387-1394
• /
• 2011

In this paper, a low-area symbol timing offset synchronization structure for WLAN Modem is proposed. Using CSD(Canonic Signed Digit) coefficients and CSS(Common Sub-expression Sharing) technique for the filter implementation, efficient structure for multiplication block can be obtained. Function simulation for proposed structure is done by using the preamble with timing offset. Through Verilog-HDL coding and synthesis, it is shown that the proposed symbol timing offset synchronization structure can be implemented with low-area semiconductor.

• Korean Journal of Biological Psychiatry
• /
• v.6 no.2
• /
• pp.235-239
• /
• 1999

Objectives : The purpose of this study was to evaluate the difference of depressive symptoms and attention between estrogen user and non-user in postmenopausal women. Methods : 30 Estrogen users and 30 non-users were participated in this study. They were all menopausal for at least 1 year and have 12 or more education years. We used BDI(Beck depression inventory), digit span and digit symbol to evaluate depressive symptoms and attention in both groups. We also measured the plasma estradiol level and identified the correlation between estradiol level and BDI, digit span and digit symbol. Results : The demographic data was not different between both groups. Estrogen users scored higher than non-users in digit span(forward) and lower than non-users in BDI. The correlation between estradiol level and BDI, digit span and digit symbol was not significant. Conclusion : Estrogen replacement therapy was effective in alleviating depressive symptoms but ineffective in improving attention in postmenopausal women.

• The Journal of Korean Medicine
• /
• v.43 no.2
• /
• pp.61-74
• /
• 2022

Objectives: This study aimed to explore the short-term effects of bilateral masticatory training using an intraoral device on memory and concentration, which is an advanced form of Gochi, compared to the unilateral form with gum. Methods: Thirty young healthy participants (age, 16-30 years) were screened and randomly assigned to one of two sequences in a crossover design. The participants assigned to sequence A (n=15) performed bilateral mastication using an intraoral device with a total of 300 taps, followed by unilateral mastication using gum with the same number of repetitions and frequency, separated by a 7-day washout period. A reverse order was used for sequence B. The primary and secondary outcomes were the digit span test result and the symbol digit modality test and the word list recall results, respectively, which were conducted before and after each intervention. Results: Symbol digit modality test scores increased by 12.03±8.33 with bilateral mastication, which was significantly higher than that obtained with chewing gum (5.17 points;95% confidence interval: 0.99, 9.34; p<0.05). Changes in the digit span test and word list recall scores were not significantly different between the two groups. In the digit span test forward, symbol digit modality test, and word list recall test, bilateral mastication was not inferior to unilateral mastication in improving memory and concentration. Conclusions: Bilateral masticatory exercises using an intraoral device are not inferior to unilateral mastication with gum for improving memory in healthy young individuals. Further research is needed to determine the efficacy of bilateral masticatory training on cognitive function.

• Journal of Yeungnam Medical Science
• /
• v.14 no.2
• /
• pp.314-328
• /
• 1997

A cross-sectional study was performed to evaluate the effects of chronic exposure to low-dose solvent on neurobehavioral performance of 48 male workers exposed to organic solvents. A control group of 50 workers was selected from same factories. Each worker completed a medical and occupational questionnaire and four tests of Neurobehavioral Core Test Battery. These included Benton visual retention test, digit symbol, digit span, and pursuit aiming. Comparison of mean performance showed a significantly poorer performance on digit symbol, digit span, and pursuit aiming. In univariate analysis, age contributed to poor performance on Benton visual retention test and educational level was found to reduce the performance on symbol digit in both groups. Amount of alcohol intake was found to reduce the performance on digit symbol and smoking appeared to slow pursuit aiming in the exposure group. In multiple regression analysis, controlling for age, educational level, alcohol, and smoking, Solvent exposure was found to be associated with performance of digit span, and number of correct dot of pursuit aiming. Age on Benton visual retention, educational level on digit symbol, arid smoking on pursuit aiming were found to be a significant factors on each test items. This study suggest that short-term memory, and perception can be affected easily by chronic exposure of organic solvents which air concentration levels were under the Threshold Limit Value.

• Journal of Preventive Medicine and Public Health
• /
• v.30 no.1 s.56
• /
• pp.171-179
• /
• 1997

This study was performed to see whether neurobehavioral tests was affected by the exposure-free time in the workers chronically exposed to organic solvents. Thirty-four female workers were participated and four items among neurobehavioral core test battery of World Health Organization, including digit span, Santa Ana Dexterity, digit symbol and Benton Visual Retention, were administered to the workers. Test was conducted three times-preshift on Monday, preshift on Weekday and during shift on Weekday-per person and the interval of tests was 2 weeks. Digit span forward, Santa Ana Dexterity, digit symbol, and Benton Visual Retention showed significant decrements by performing time, especially during shift on Week-day versus preshift on Monday and preshift on Weekday. In addition, the score at preshift on Weekday was significantly lower than preshift on Monday, in preferred Santa Ana Dexterity and digit symbol. Generally, those who were exposed to high concentration, over 50 years and under 6 years of education showed marked decrease of score at during shift. So, it would be desirable that neurobehavioral test is conducted at preshift on Monday and items related to short term memory could be considerable to be done at preshift on Weekday.

• Journal of Preventive Medicine and Public Health
• /
• v.26 no.2 s.42
• /
• pp.210-221
• /
• 1993

In order to evaluate the confounding factors of neurobehavioral tests and the neurobehavioral effects in the workers exposed to organic solvents, NCTB was carried out on 100 workers. 46 workers had never been exposed to neurotoxic substances, and the others were being exposed to the solvents, mainly toluene. Simple reaction time, digit symbol, Santa Ana dexterity test and persuit aiming were different with age in non exposure group. Simple reaction time was carried out well in males, and digit symbol and persuit aiming were in females. There was no difference at educational level when the subject was educated over 12 years. Santa Ana dexterity and Benton visual test differed according to exposure level to toluene, however simple reaction time didn't. The acute neurotoxic effect was not excluded in this study. But, NCTB could be used to evaluate and prevent neurobehavioral changes in workers exposed to neurotoxic solvents in Korea.

• Journal of Yeungnam Medical Science
• /
• v.14 no.1
• /
• pp.183-196
• /
• 1997

An experimental study was performed to investigate. The subjects drank (0.5g/kg ethanol and performed 7 items of SPES(simple reaction time, color word stress, digit classification, finger tapping speed, numerical ability, symbol digit coding, memory digit span). 20 students of medical college participated in the study during August, 1996. After ethanol intake, performance of 4 items(simple reaction time, digit classification, finger tapping speed, symbol digit coding) significantly showed to be decreased. The function of perception-response speed and steady movement were found to be more sensitive to ethanol than that of short-term memory, numerical ability and specification of color. No significant association were found between smoking, alcohol drinking, BMI(body mass index) and the effects of ethanol on neurobehavioral performance.