The changes of electroencephalogram(EEG) in patients with dementia are most commonly studied by analyzing power or magnitude in certain traditionally defined frequency bands. However because of the absence of on identified metric which quantifies the complex amount of information, there are many limitations in using such a linear method. According to chaos theory, irregular signals of EEG cal also result from low dimensional deterministic chaos. Chaotic nonlinear dynamics in the EEG can be studied by calculating the correlation dimension. The authors have analyzed EEG epochs from three patients with dementia of Alzheimer type and three matched control subject. The result showed that patients with dementia of Alzheimer type had significantly lower correlation dimension than non-demented controls on 12 channels. Topographic analysis showed that the correlation dimensions were significantly lower in patients with Alzheimer's disease on frontal, temporal, central, and occipital head regions. These results show that brains of patients with dementia with dementia of Alzheimer type have a decreased complexity of electrophysiological behavior. We conclude that the nonlinear analysis such as calculating correlation dimension can be a promising tool for detecting changes in the complexity of brain dynamics.
Alzheimer Disease ; Brain ; Dementia* ; Electroencephalography* ; Head ; Humans ; Nonlinear Dynamics*

No abstract available.
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Background: With the ultimate goal of developing chatbot content to address consumer inquiries about pressure injuries (PIs), this study analyzed consumer perceptions of PI using big data. Methods: This study collected text data, with PI as the central word, from three search engines (Naver, Daum, Google) from January 2019 through December 2022, using Textom version 4.5. The words were refined through text mining, keyword analysis, and TF-IDF (term frequency-inverse document frequency) analysis. N-gram analysis and centrality visualization were conducted using Ucinet 6.0. The keywords and frequencies were clustered based on the frequency of words used in CONCOR (convergence of iteration correlation) analysis. Results: Consumers for PI showed a high perception of common sites for PI, concept of PI, healthcare facility for PI, PI products, PI care, PI-related life, and PI-related disease. Conclusion Development of chatbot content customized to consumers’ needs, based on seven clusters associated with consumers’ perception of PI obtained through extensive data analysis with PI as the central word, is expected to make a significant contribution to improving consumers’ understanding of PI and enhancing the quality of PI management.

OBJECT: It seemed worthwhile to estimate nonlinear measures of the electroencephalogram (EEG) in schizophrenic patients, because nonlinear measures might serve as indicators of the specific brain function in schizophrenia. METHOD: Previous studies which estimated the chaoticity in the brain of schizophrenia with nonlinear methods recorded the EEGs at limited electrodes, so we tried to record EEGs from 16 channels for nonlinear analysis in 19 patients with Schizophrenia and 8 healthy control subjects. We employed a new method to calculate the nonlinear invariant measures. For limited noisy data, this algorithm was strikingly faster and more accurate than previous ones. RESULTS: Our results showed that the schizophrenic patients had lower values of the largest positive Lyapunov exponent at the left inferior frontal and anterior temporal head regions compared with normal controls. CONCLUSIONS: These results suggest that the nonlinear analysis of the EEGs such as the estimation of the largest positive Lyapunov exponent seems to be a useful tool in analyzing EEG data to explore the neurodynamics of the brain of schizophrenic patients.
Brain ; Electrodes ; Electroencephalography* ; Head ; Humans ; Nonlinear Dynamics* ; Schizophrenia*

Accurate transfer of the maxillo-mandibular relationship to an articulator (i.e., mounting) is critical in prosthetic treatment procedures. In the current study, a PubMed search was performed to review the influencing factors for the maxillo-mandibular relationship’s accuracy. The search included digital mounting as well as conventional gypsum cast mounting. The results showed that a greater amount of displacement was introduced during positioning the maxillary and mandibular models to interocclusal records rather than the dimensional change of registration material. Most intraoral scanners resulted in an accurate reproduction of the maxillo-mandibular relationship for posterior quadrant scanning;however, the accuracy was declined as the scan area increased to a complete arch scan. The digital mounting accuracy was also influenced by the image processing algorithms and software versions, especially for complete arch scans.

Purpose: Fluid therapy for diarrhea-induced dehydration inadvertently increases emergency department length of stay (EDLOS). To prevent this delay, we investigated the usefulness of triage using point-of-care (POC) lactate in infants with diarrhea. Methods: This study was performed on infants with diarrhea who visited the emergency department from January 2019 through December 2020. According to the POC lactate concentration and the Korean Triage and Acuity Scale (KTAS) level, the infants were separately divided into the low (< 2 mmol/L), moderate (2-3.9), and high (≥ 4) lactate groups and the mild (KTAS 4-5) and severe (1-3) groups, respectively. Using these 2 group designations, we compared variables regarding the emergency medicine resource use and outcomes. To predict the prolonged EDLOS (≥ median value) we performed logistic regression and receiver operating characteristic analyses. Results: A total of 540 infants were included. The median of EDLOS was 169 minutes (interquartile range, 103-220). Fluid therapy was more frequently performed in the high lactate group than in the low-moderate lactate groups (85.0% vs. 60.4%-73.6%; P = 0.025). The high lactate and severe groups respectively showed higher rates of hospitalization (40.0% vs. 3.8%-7.6% [P < 0.001] and 10.9% vs. 1.4% [P = 0.015]), and longer median EDLOS (259 minutes vs. 147-178 [P < 0.001] and 185 vs. 131 [P = 0.001]) compared to the low-moderate lactate and mild groups. Compared to the KTAS, lactate is more strongly associated with the prolonged EDLOS (lactate, adjusted odds ratio, 4.80 [95% confidence interval, 1.87-15.34] vs. KTAS, 3.52 [1.90-6.54]). The areas under curve for lactate and for the KTAS were 0.66 (0.60-0.73) and 0.62 (0.55-0.69), respectively (P = 0.058). Conclusion In infants with diarrhea, POC lactate can be a predictor of emergency medicine resource use and outcomes.

We would like to correct the degree for the 2nd author.

OBJECTIVES: Prenatal testosterone is known to influence both cerebral laterality and 2nd to 4th digit ratio (2D : 4D). Epigenetic changes are thought to play some role in it. We studied sex-related differences between 2D : 4D and cerebral laterality in patients with schizophrenia and controls to examine the effects of prenatal testosterone in the development of schizophrenia. METHODS: Forty one men (18 schizophrenic patients and 23 controls) and 40 women (17 schizophrenic patients and 23 controls) were recruited from one psychiatric hospital in Korea. The 2D : 4D and electroencephalographic (EEG) coherence in 19 channels (66 pairs of interhemispheric coherence and 54 pairs of intrahemispheric coherence) were measured. The sex-related statistical analyses between 2D : 4D and EEG coherence in controls and patients with schizophrenia were performed using multiple regression. RESULTS: In male patients, the relationship between 2D : 4D and right intrahemispheric EEG coherence showed mainly positive correlation in delta and theta frequency bands, while it showed negative correlation in male controls. In female patients, the relationship between 2D : 4D and interhemispheric EEG coherence showed stronger positive correlation in alpha and beta frequency bands, while it showed weaker positive correlation in female controls. CONCLUSIONS: Low prenatal testosterone may play certain roles in altered correlation between 2D : 4D and cerebral laterality in schizophrenia and the development of schizophrenia by epigenetic mechanism.
Electroencephalography ; Epigenomics ; Female ; Hospitals, Psychiatric ; Humans ; Korea ; Male ; Schizophrenia* ; Testosterone

OBJECTIVES: Cerebral laterality is thought to be an important marker for neurodevelopment. Prenatal testosterone could influence both cerebral laterality and 2nd to 4th finger length ratio(2D:4D). EEG coherence and 2D:4D were examined to investigate the relationship between prenatal testosterone level and cerebral laterality. METHODS: EEG was recorded in 24 healthy subjects in the eyes closed resting state. Differences in 2D:4D finger ratio were used to discriminate "masculine finger type" and "feminine finger type" groups. The 2D:4D ratio was lower and greater than one for the "masculine finger type" group and "feminine finger type" group, respectively. We used coherence analysis to estimate the cortical functional connectivity. RESULTS: There were statistically meaningful relationships among cerebral functional connectivity, sex and finger ratio. Man and masculine finger type group showed higher intra-hemispheric coherence than those of woman and feminine finger type group. Woman and feminine finger type group showed higher inter-hemispheric coherence than those of man and masculine finger type group. CONCLUSIONS: These results imply that prenatal testosterone might act as important determinants of cerebral laterality. Further examination of the relationship between 2D:4D and EEG coherence in schizophrenia could give some clues for the neurodevelopmental hypothesis of schizophrenia genesis.
Electroencephalography ; Eye ; Female ; Fingers ; Humans ; Schizophrenia ; Testosterone

OBJECTIVES: Sex hormones exposure during the prenatal period has an effect on cerebral lateralization. Male brains are thought to be more lateralized than female brains. Bipolar disorder was known to show abnormalities in cerebral laterality whose characteristics could be estimated by electroencephalography (EEG) coherences. We studied sex-related differences of EEG coherences between healthy controls and patients with bipolar disorder to examine the sex effects in the genesis of bipolar disorder. METHODS: Participants were 25 patients with bipolar disorder (11 male, 14 female) and 46 healthy controls (23 male, 23 female). EEG was recorded in the eyes closed resting state. To examine dominant EEG coherence associated with sex differences in both groups within five frequency bands (delta, theta, alpha, beta, and gamma) across several brain regions, statistical analyses were performed using analysis of covariance. RESULTS: Though statistically meaningful results were not found, some remarkable findings were noted. Healthy control females showed more increased interhemispheric coherences than control males in gamma frequency band. There were no differences in the intrahemispheric coherences between the healthy control males and females. In patients with bipolar disorder, female dominant pattern in interhemispheric coherences was attenuated compared with healthy control. CONCLUSIONS: Sex differences of EEG coherences, which could be a marker for cerebral laterality, were attenuated in patients with bipolar disorder compared with healthy controls. These results imply that abnormal sex hormone exposure during early development might play some role in the pathogenesis of bipolar disorder.
Bipolar Disorder* ; Brain ; Electroencephalography* ; Female ; Gonadal Steroid Hormones ; Humans ; Male ; Sex Characteristics